The cylindrical antenna with nonreflecting resistive loading

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AMSCO V-PRO MAX 低温 sterilization 系统（仅适用于非美国地区）说明书

AMSCO ® V-PRO ® MAX LOW TEMPERATURESTERILIZATION SYSTEM (For Use Outside U.S.A. Only)Item ________________________Location(s)_______________________________________________The Selections Checked Below Apply To This EquipmentUNIT POWER SUPPLY ❑North America:200-208/230 Vac, 3 phase, 50/60 Hz, 16 Amp ❑Europe/Asia:400 Vac, 3 phase, 50 Hz, 10 Amp ❑Japan:200 Vac, 3 phase, 50/60 Hz, 16 AmpLABELS AND MANUALS ❑French ❑Finnish ❑ Danish ❑Italian ❑Russian ❑ Portuguese ❑German ❑Polish ❑ Hungarian❑Spanish ❑ JapaneseMOUNTING❑Single Door, Cabinet ❑Single Door, Recessed ❑Double Door, CabinetAPPLICATIONThe Amsco V-PRO maX Low Temperature Sterilization System is intended for use in the terminal sterilization of properly prepared (cleaned, rinsed and dried) reusable metal and nonmetal medical devices used in Healthcare Facilities. The STERIS developed low pressure and low temperature Sterilization Cycles are suitable for sterilizing medical devices sensitive to heat and moisture.The Amsco V-PRO maX Low Temperature Sterilization System performs three pre-programmed Sterilization Cycles: the Lumen Cycle (approximately 55 minutes to complete), the Non Lumen Cycle (approximately 28minutes to complete) and the Flexible Cycle (approximately 35 minutes to complete).This sterilization system using the Lumen Cycle can sterilize* the following:1.Lumened and non-lumened instruments with diffusion-restricted spaces such as the hinged portion of forceps and scissors.2.Medical devices (including single, dual and triplechanneled rigid and semi-rigid endoscopes) with the following configurations:1•Single channeled devices with a stainless lumen thatis ≥0.77mm (~1/32") internal diameter (D) and ≤500mm (19-11/16") in length•Dual channeled devices with stainless lumens thatare ≥0.77mm (~1/32") ID and ≤ 527 mm (20-3/4") in length•Triple channeled devices with stainless lumens thatare either:»≥ 1.2 mm (~3/64") ID and ≤ 275 mm (~10-55/64")in length»≥ 1.8 mm (~5/64") ID and ≤ 310 mm (~12-13/64")in length»≥ 2.8 mm (~7/64") ID and ≤ 317 mm (12-31/64") in length1Validation testing for all channel/lumen sizes was conducted using a ma ximum of 20 lumens per loa d. Hospita l loa ds should not exceed this validated number of lumens. Validation studies were performed using a va lida tion loa d consisting of two instrument trays and two pouches for a total weight of 8.91kg (19.65 lb).This sterilization system using the Non Lumen Cycle can sterilize 2 non-lumened instruments including non-lumened rigid, semi-rigid and flexible endoscopes and non-lumened instruments with stainless-steel diffusion-restricted areas such as the hinged portion of forceps or scissors.2Validation studies conducted using validation load of two instrument trays and two pouches for a total weight of 8.91kg (19.65 lb).This sterilization system using the Flexible Cycle can sterilize single or dual lumen surgical flexible endoscopes (such as those used in ENT, Urology and Surgical Care) and bronchoscopes in either of two configurations:1.Two flexible endoscopes with a light cord (if not integral to endoscope) and mat with no additional load.3 The flexible endoscopes may contain either:» A single lumen with an inside diameter of ≥ 1 mm (~3/64") and a length of ≤ 1050 mm (41")»Or two lumens with:•One lumen with an inside diameter of ≥ 1 mm (~3/64") and a length of ≤ 998 mm (39")•And the other lumen with an inside diameter of ≥ 1mm (~3/64") and a length of ≤ 850 mm (33")3The valida tion studies were conducted with two flexible endoscopes, ea ch pa cka ged into a tra y with silicone ma t a nd light cord (if not integra l to endoscope).(Typical - details may vary.)2.One flexible endoscope with a light cord (if not integral toendoscope) and mat and additional non-lumenedinstruments including instruments with diffusion-restricted areas such as the hinged portion of forcepsand scissors.4The flexible endoscope may containeither:» A single lumen with an inside diameter of ≥ 1 mm (~3/64") and a length of ≤ 1050 mm (41")»Or two lumens with:•One lumen with an inside diameter of ≥ 1 mm(~3/64") and a length of ≤ 998 mm (39")•And the other lumen with an inside diameter of≥ 1mm (~3/64") and a length of ≤ 850 mm (33")4The validation studies were conducted with a flexible endoscope in a tray with silicone mat and light cord (if not integral to endoscope). Also included in the load were an additional instrument tray and one pouch for a total weight of 11kg (24lb).DESCRIPTIONThe Amsco V-PRO maX Low Temperature Sterilization System is specifically designed to only process goods using vaporized hydrogen peroxide under vacuum conditions. The process is fully automated, is compatible with a broad range of materials and has rapid Sterilization Cycle times. There are no toxic by-products created by the Sterilization Cycle – only water vapor and oxygen are produced.The Amsco V-PRO maX Low Temperature Sterilization System is NOT intended to process liquids, linens, powders or cellulose materials.The system utilizes specially designed, disposable, multi-use Cartridges (available separately) containing VAPROX® HC Sterilant and is available in either a single door (freestanding or recessed) or double door configuration.Articles to be sterilized are placed on a racking system within the aluminum chamber. An automated control enables the cycle to be started and monitored by the operator. The touch screen is user friendly and easy to operate.System installation requires no plumbing, ventilation or air supply – only a dedicated electrical connection is needed. A power cord is supplied for this connection.STANDARDSThis Amsco V-PRO maX Low Temperature Sterilization System meets the applicable requirements of the following standards, as certified by INTERTEK Testing Services:•Underwriters Laboratories (UL) Standard UL 61010-1, Second Edition•Canadian Standards Association (CSA) CAN/CSA 22.2 No. 61010-1, Second EditionGoverning Directive for the affixing of the CE mark: •Medical Device Directive (MDD) 2007/47/ECStandards applied to demonstrate conformity to the directives:•EN 61010-1•EN 60601-1-2•EN 14937•IEC 61010-2-040Each sterilization system is designed, fabricated, assembled and tested in accordance with all applicable sections of UL and CSA.SIZE (W X H X L)Overall Dimensions:•838 x 1908 x 973 mm (33 x 75-1/8 x 38-5/16")Chamber Size:•432 x 381 x 826 mm (17 x 15 x 32-1/2")Chamber Volume:•136 L (4.8 cubic feet)FEATURESThe chamber and door assembly are aluminum equipped with a silicone rubber gasket for each door and a welded backhead on single door units.Insulation fitted on the chamber wall exterior, door and backhead is 25mm (1") thick (nominal). Insulation is held in place with hook-and-loop closures.Insulation is constructed of asbestos- and chloride-free, oil and water resistant (silicone impregnated) fiberglass.Automatic door locking mechanism keeps the sterilization system door locked during the entire Sterilization Cycle. After cycle completion, air pressure is used to unlock the door. The sterilizer door cannot be opened if either electrical power or air pressure is lost during sterilizer operation. When sterilization system is in Standby mode, there are no door opening restrictions. Chamber heating is achieved through electric strip heaters attached to the chamber sides, bottom wall, door and backhead. Operating temperature is approximately 50°C (122°F)Sterilant cartridge interface only accepts VAPROX HC Sterilant Cartridges (Cups). The system control automatically tracks the amount of VAPROX HC Sterilant used and the Sterilant expiration date. The control prompts the user on the control display when a new Cup is needed.The proprietary Cartridge is equipped with a data matrix code to ensure the correct Cup is used in the sterilization unit and that the Cup contents are not expired; no Cup code (or other information) needs to be entered by the user.Catalytic converter receives outflow from chamber during all cycle phases. Catalytic converter converts hydrogen peroxideinto water vapor and oxygen.CartridgeInterfaceHMI Display PrinterOther Components:The following are furnished to obtain a complete working unit, ready for (but not including) connection to the facility service lines:•Resistive Thermal Detectors (RTDs) are installed for sensing and displaying temperature control of vaporizer and chamber. Signals from all system RTDs, converted into electrical impulses, provide accurate control inputs and readouts throughout the entire cycle.•Pressure Transducers are installed for sensing and displaying chamber pressure control. Signals from allsystem pressure transducers, converted into electricalimpulses, provide accurate control inputs and readouts throughout the entire cycle.•Pneumatic and Solenoid Valves and Switches are used in the sterilization system design to simplify piping andincrease serviceability.•Air Supply and Vacuum Filters are supplied to ensure air entering chamber is HEPA (High Efficiency Particulate Air) filtered (prevent chamber recontamination) and airexhausted from vacuum pump is free of entrapped oil and odor.•Sterilization System Panels are constructed of plastic and stainless steel.•Sterilization System Frame and support system is constructed of welded carbon steel with protective paint.•High Power Vacuum Pump is supplied to produce cycle vacuum pulses that remove air and moisture from thechamber. The direct drive rotary vane pump is quiet(<60dB) with low vibration. A powerful 2.2 kW (3 HP)motor produces a displacement of 90 m3/hr (53 CFM) and helps alleviate moisture sensitivity in the sterilization unit.The Sterilizer operating pressure is from atmosphericpressure down to less than 1 Torr.CONTROL DESCRIPTIONThe Amsco V-PRO maX Low Temperature Sterilization System is equipped with an Allen-Bradley Compact Logix™ (Panel View Plus™ 6 1000 Display1) control system and an impact printer.•Control Display Panel is located on the front of the sterilization unit in the center while facing the unit. Thiscolor touch panel provides user information and allows user inputs. The display is a 640 x 480 pixel resolution,10.4" screen. Use of this panel and associated screens isnormally self-explanatory. The screens are color coded for operator convenience as follows:»Control Screens -»Condition Phase - Green»Sterilize Phase - Blue»Aeration Phase - Violet»Service Screens - Light Blue»Option Screens - Purple»Alarm Screens - RedNOTE: This Sterilization System permits no manual control of the Sterilization Cycles.The Ready, Status, Standby and Cup Empty screensinclude a cup level indicator (similar to a cell phone battery indicator) in the lower right corner (see Typical Operator Screens). For normal operation, each bar representsapproximately four cycles remaining (e.g., four bars means cup contains enough sterilant for 13-16 cycles).•Printer is located on the front of the sterilization unit on the right side while facing the unit. This alphanumeric impact printer provides an easy to read permanent record of the Sterilization Cycle. Printer provides a 5.7cm (2-1/4"), 24-character wide cycle tape and paper take-up.1CompactLogix™ and PanelView™ Plus 6 1000 are trademarks ofAllen-Bradley, a Rockwell Automation Company.p yTypical Operator ScreensCYCLE DESCRIPTIONThe Amsco V-PRO maX Low Temperature Sterilization System is equipped with three pre-programmed Sterilization Cycles: Lumen Cycle (approximately 55 minutes to complete),Non Lumen Cycle (approximately 28 minutes to complete) and Flexible Cycle (approximately 35 minutes to complete). Each Sterilization Cycle proceeds through three phases: CONDITION, STERILIZE and AERATION.•CONDITION – Lumen Cycle: This cycle phase is a set time vacuum pulse to remove air and moisture from thechamber. When setpoint is reached, load is tested foracceptable moisture content. If content is acceptable,cycle proceeds. If not, Condition pulse repeats.Non Lumen Cycle: This cycle phase is a vacuum pulse to remove air and moisture from the chamber. When setpoint is reached, load is tested for acceptable moisture content. If content is acceptable, cycle proceeds. If not, Condition pulse as identified for Lumen Cycle is initiated.Flexible Cycle: This cycle phase is a vacuum pulse toremove air and moisture from the chamber. When setpoint is reached, load is tested for acceptable moisture content. If content is acceptable, cycle proceeds. If not, Condition pulse as identified for Lumen Cycle is initiated.NOTE: If Condition phase fails the second moisture check, the cycle Aborts.•STERILIZE – This cycle phase is a series of four pulses.Each pulse consists of: vacuum pulled to setpoint;VAPROX HC Sterilant vapor drawn into chamber; hold for programmed time; filtered air is introduced to setpoint; hold for programmed time; deep vacuum pulled to setpoint.•AERATION – This cycle phase pulls a vacuum to setpoint and continues to evacuate for programmed time to reduce chamber vapor concentration. Once Aeration phase iscomplete, chamber pressure returns to atmospheric and chamber door is unlocked.PREVENTIVE MAINTENANCECustomers are encouraged to contact STERIS concerning annual maintenance programs. Preventive maintenance, adjustments and replacement of worn parts are provided on a scheduled basis to help ensure optimal equipment performance and help minimize untimely and costly interruptions. STERIS maintains a worldwide staff of well-equipped, factory-trained technicians to provide these services, as well as on-site installation, training, and expert repair services. Contact STERIS for details.CUSTOMER IS RESPONSIBLE FOR COMPLIANCE WITH APPLICABLE LOCAL AND NATIONAL CODES AND REGULATIONS.NOTES1.For general installation information, refer to STERIS GeneralNotes for Sterilizers (drawing 062941-091). This drawing should always accompany the equipment drawing.2.Refer to equipment drawing showing all utility and spacerequirements for actual installation specifications.Clearances shown are minimum required for servicingequipment. Floor surface must be hard and level.3.STERIS recommends maintaining and operatingsterilization system in area where temperature does not exceed 40°C (104°F) and has ventilation systemexchanging area air at least 10 times per hour.4.STERIS recommends a dedicated, grounded electricalcircuit be provided for each unit. Use of an extension cord is not recommended.5.Consult MSDS regarding storage and handling ofVAPROX HC Sterilant Cartridges (Cups).6.Unit weight: Single Door – 386 kg (850 lb) recessed and463kg (1020 lb) free-standing; Double Door – 562kg(1240lb) recessed one wall.7.Heat loss at 21°C (70°F) – Peak=1,046 BTU/hr;Avg.=942BTU/hr.8.Electrical Consumption, per cycle=2.2 kW-hr average;out of cycle=0.7 kW-hr average.9.STERIS assumes no responsibility for changes to theSterilization Unit made necessary through failure to observe the supplied necessary specifications (e.g., incorrect facility power supply). Specifications are subject to change without notice.EQUIPMENT DRAWINGS (REQUIRED FOR INSTALLATION)Equipment DrawingPart NumberEquipment Drawing Title129385-449Single Door, Recessed 129385-450Single Door, Cabinet 129385-451Double Door, CabinetSINGLE DOOR, CABINET MODEL SHOWNDimensions are in inches [mm]Not Fo rI n s t a l l at i o n SIDE VIEW PLAN VIEWFRONT VIEWDrawing is not to scale.Dimensions are typical.30 1/2[775]DOOR SWINGFor Further Information, contact:STERIS Corporation5960 Heisley RoadMentor, OH 44060-1834 • USA440-354-2600 • 800-548-4873This document is intended for the exclusive use of STERIS Customers, includingarchitects or designers. Reproduction in whole or in part by any party other than。

IEEE standard definitions of terms for antennas 145-1993

The Institute of Electrical and Electronics Engineers, Inc. 345 East 47th Street, New York, NY 10017-2394, USA Copyright © 1993 by the Institute of Electrical and Electronics Engineers, Inc. All rights reserved. Published 1993. Printed in the United States of America ISBN 1-55937-317-2
IEEE Std 145-1993
(Revision of IEEE Std 145-1983)
IEEE Standard Deﬁnitions of Terms for Antennas
Sponsor
Antenna Standards Committee of the IEEE Antennas and Propagation Society
Approved March 18, 1993
IEEE Standards Board
Abstract: Definitions of terms in the field of antennas are provided. Keywords: antennas, definitions, propagation, terminology
IEEE Standards documents are adopted by the Institute of Electrical and Electronics Engineers without regard to whether their adoption may involve patents on articles, materials, or processes. Such adoption does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the standards documents.

CHEMICON International, Inc. 鼠抗tau-1单抗产品说明书

MOUSE ANTI-TAU-1MONOCLONAL ANTIBODYCATALOG NUMBER:MAB3420 (formerly Roche Catalog Number 1289977)LOT NUMBER:QUANTITY:100 µgCONCENTRATION: 1 mg/mLSPECIFICITY:MAB3420 binds to all known electrophoretic species of tau in human, rat and bovine brain(one-dimensional SDS-PAGE).BACKGROUND:Cellular and subcellular localization: In situ, anti-tau-1 has a stringent specificity for theaxons of neurons. The antibody does not stain the cell bodies or dendrites of neurons, nordoes it stain any other cell type (4). However, this in vivo intracellular specificity is notmaintained in culture: anti-tau-1 stains the axon, cell bodies, and dendrites of rathippocampal neurons grown in culture (5).The specificity of anti-tau-1 was originally thought to represent the restricted expression oftau to axons. Later studies revealed that this specificity is dependant on the state ofphosphorylation. In dephosphorylated samples (samples treated with alkalinephosphatase) anti-tau-1 stains astrocytes, perineuronal glial cells, and the axons, cellbodies and dendrites of neurons, while in untreated samples, anti-tau-1 stains only axons(6). (The epitope recognized by anti-tau-1 is probably at or near a phosphorylated site.) IMMUNOGEN: Purified denatured bovine microtubule associated proteins.ISOTYPE: IgG2aCLONE NAME: Tau-1 (PC1C6, reference 4)APPLICATIONS:Western blot: Bovine brain microtubule proteins purified by two cycles of assembly anddisassembly (9) are dissolved in SDS-PAGE sample buffer. Five micrograms of themicrotuble preparation per lane is loaded onto a 4% to 20% SDS-PAGE gradient gel alongside molecular weight markers (14.3 – 200 kD). After separation by electrophoresis, theproteins are blotted onto nitrocellulose. Tau is detected as a series of 5 bands (52-68 kD)with approximately 5 ng/mL of anti-tau-1.Immunohistochemistry: 5 µg/mLOptimal working dilutions must be determined by end user.SPECIES REACTIVITIES:Human, rat and bovine.FORMAT:Purified immunoglobulin.PRESENTATION:Liquid. Buffer = 10 mM potassium phosphate, 70 mM NaCl, pH 7.4.STORAGE/HANDLING:Maintain frozen at -20°C in undiluted aliquots for up to 12 months after date of receipt.Avoid repeated freeze/thaw cycles.For research use only; not for use as a diagnostic.REFERENCES: 1. Francon, J. et al. (1982) Eur. J. Biochem. 129: 465.2. Binder, L.I. et al. (1986) Annals of the New York Academy of Sciences 466: 145.3. Goedert, M. et al. (1989) Neuron 3:519.4. Binder, L.I. et al. (1985) J. Cell Biol. 101:1371.5. Dotti, C.G. et al. (1987) Neuroscience 101:1371.6. Papasozomenos, S.C. et al. (1987) Cell Motility and the Cytoskeleton 8:210.7. Wood, J.G. et al. (1986) A 83:4040.8. Grundke, Iqbal et al. (1986) A 83:4913.9. Shelanski, M.L. et al. (1973) A 70:765.10. Hsu, S. et al. (1981) Am. J. Clin. Pathol. 75:734.11. Falini, B. and Taylor, C.R. (1983) Arch. Pathol. Lab. Med. 107:105.12. Harlow, E. and Lane, D. (1988) Antibodies: A Laboratory Manual p. 359, Cold SpringHarbor Laboratory, N.Y.13. Taylor, C.R. (1978) Arch. Pathol. Lab. Med. 102:113.14. Iwata, N., et al., J. Neuroscience (2004) 24:991-998.15. Jiang, H., et al., Cell (2005) 120:123-135.16. Yoshimura, T., et al., Cell (2005) 120:137-149.17. Stagi, M., et al., J. Neuroscience (2005) 25:352-362.18. Cheng, L., et al., J. Neuroscience (2005) 25:395-403.19. Kishi, M., et al., Science (2005) 307:929-932.20. Lee, S., Molecules and Cells (2005) 20:256-262.Immunohistochemistry ProtocolDephosphorylation of tissue sections (optional)Dephosphorylation with alkaline phosphatase is recommended for staining neurofibrillary tangles in Alzheimer’s brain tissue with anti-tau-1 (6). This treatment changes the staining pattern of anti-tau-1 to include cell bodies, dendrites and axons of neurons. In untreated samples, anti-tau-1 stains axons only.1. Incubate tissue sections at +32°C for2.5 hours with constant agitation in the following solution: 100 mM Tris-HCl, pH 8.0; 130 units/mL alkaline phosphatase, 1 mM PMSF, 10 µg/mL pepstatin and 10 µg/mL leupeptin.2. Rinse sections twice, 3 min per rinse, with 100 mM Tris-HCl, pH 8.0.Anti-tau-1 staining1. Block non-specific binding by incubating sections in PBS containing 1% (v/v) normal animal serum, and 0.03%(w/v) Triton X-100. The animal serum should be from the same species as the secondary antibody.2. Rinse 3 times with PBS, 3 min per rinse.3. Incubate sections with anti-tau-1, approximately 5 µg/mL, diluted in PBS containing 1% (v/v) normal animalserum.4. Wash with PBS, changing the solution 3 times over a 3 min period.5. Detect with a standard secondary antibody detection system (10-13).Important Note:During shipment, small volumes of product will occasionally become entrapped in the seal of the product vial. For products with volumes of 200 µL or less, we recommend gently tapping the vial ona hard surface or briefly centrifuging the vial in a tabletop centrifuge to dislodge any liquid in thecontainer’s cap.For research use only; not for use as a diagnostic.* Triton X is a registered trademark of Rohm & Haas, Philadephia, PA, USA.For research use only; not for use as a diagnostic.。

A compact antenna for 4G mobile handset天线

The transmitter and receiver are placed at a distance of 120mm.From Figure 17,it is observed that the variation of group delay for proposed antenna is small across the whole oper-ating band except the two notch bands.The phase of S 21(Fig.18)is relatively linear from 3.11to 10.6GHz excluding the notch bands in face to face mode.This indicates that the antenna has a good time domain characteristics and small pulse distortion.6.CONCLUSIONTo avoid the interference among the UWB and narrow systems,a microstrip feed dual notch UWB antenna has been proposed.The desired stop bands are realized by EBG structures.The input impedance and simulated surface distributions are used to analyze the physical effects of the EBG.The existences of the EBG have little effects on the radiation pattern.Satisfactory per-formances have been observed in respect of BW,radiation pat-tern,gain,group delay,and phase response.Therefore,the proposed antenna is expected a suitable candidate for UWB applications.REFERENCES1.P.Li,J.Liang,and X.Chen,Study of printed elliptical/circular slot antennas for ultra-wide band applications,IEEE Trans Antennas Propag 54(2006),1670–1675.2.K.P.Ray and S.Tiwari,Ultra wideband printed hexagonal monopole antennas,IET Microwaves Antennas Propag 4(2010),437–445.3.X.J.Liao,H.C.Yang,N.Han,and Y.Li,Aperture UWB antenna with triple band-notched characteristics,Electron Lett 47(2011),77–79.4.H.Chen,Y.Ding,and D.S.Cai,A CPW fed UWB antenna with WiMAX/WLAN band notched characteristics,Prog Electromagn Res Lett 25(2011),163–173.5.W.T.Li and Y.Q.Hei,Design of a ultra wide band antenna with multiple band notch characteristics,J Electromagn Waves Appl 26(2012),942–951.6.H.H.Xie,Y.C.Jiao,L.N.Chen,and F.S.Zhang,Omnidirectional horizontally polarized antenna with EBG cavity for gain enhance-ment,Prog Electromagn Res Lett 15(2010),79–87.7.A.Pirhadi,M.Hakkak,and F.Keshmiri,Using electromagnetic band gap superstrate to enhance the bandwidth of probe-fed micro-strip antenna,Prog Electromagn Res 61(2006),215–230.8.R.Makinen,V.Pynttari,J.Heikkinen,and M.Kivikoski,Improve-ment of antenna isolation in hand-held devices using miniaturized electromagnetic band gap structures,Microwave Opt Technol Lett 49(2007),2508–2513.9.M.Yazdi and N.Komjani,Design of a band-notched UWB monop-ole antenna by means of an ebg structure,IEEE Antenna Wireless Propag Lett 10(2011),170–173.10.L.Peng and C.L.Ruan,UWB band-notched monopole antennadesign using electromagnetic-bandgap structures,IEEE Trans Micro-wave Theory Tech 59(2011),1074–1081.11.J.J.Xie,Y.Z.Yin,J.Wang,and S.L.Pan,A novel tri-band circularslot patch antenna with an EBG structure for WLAN/WiMAX appli-cations,J Electromagn Waves Appl 26(2012),493–502.12.J.Xu,C.Miao,G.Yang,L.Cui,J.D.Zhang,Y.X.Ji,and W.Wu,Compact and sharp rejection microstrip UWB BPF with dual narrow notched bands,J Electromagn Waves Appl 25(2011),2464–2474.13.F.Xu,Z.X.Wang,X.Chen,and X.A.Wang,Dual band-notchedUWB antenna based on spiral electromagnetic-band gap structure,Prog Electromagn Res B,39(2012),393–409.14.T.Li,H.Q.Zhai,G.H.Li,and C.H.Liang,Design of compact UWBband-notched antenna by means of electromagnetic-band gap struc-tures,Electron Lett 48(2012),608–609.VC 2014Wiley Periodicals,Inc.A COMPACT ANTENNA FOR 4G MOBILE HANDSETLi Jiu-Sheng and Wu DiSchool of Electronics and Information Engineering,China Jiliang University,Hangzhou 310018,China;Corresponding author:jshli@Received 3February 2014ABSTRACT:In this article,we propose a compact antenna using S-shaped shorted strip and inverted L-shaped shorted strip for 4GmobileFigure 16Measured radiation patterns (a)H-plane and (b)E-plane.[Color ﬁgure can be viewed in the online issue,which is available at]Figure 17Measured groupdelayFigure 18Measured phasehandset.The measured impedance bandwidth defined by VSWR <3of 750MHz (0.66–0.81GHz),2.6GHz (2.25–2.85GHz)and 3.5GHz (3.28–3.97GHz)are obtained,with the peak gains of 3.0/4.7/3.6dBi.The presented antenna has a small size of only 21315mm 2and dem-onstrates omnidirectional radiation patterns,which show good perform-ance for 4G application.The measured results are in agreement withthe simulation.VC 2014Wiley Periodicals,Inc.Microwave Opt Technol Lett 56:2199–2203,2014;View this article online at .DOI 10.1002/mop.28540Key words:4G mobile handset;compact antenna;small size 1.INTRODUCTIONThe personal mobile terminal equipments have been required to operate in multiband to meet a variety of communication serv-ices.It is very important for the antenna of personal mobile communication device to be with small size and many operating bands.In the last two decades,to realize the miniaturization and multifrequency,many design schemes have been proposed by researchers [1–4].More recently,after the release of 4G,it receives much attention and developed widely and rapidly,due to its properties of low-power consumption,support of high data rate and simple configuration.Conversely,with the rapid devel-opment of 4G Era,especially the LTE,a great demand is being given for designing antennas that can support several different services and standards.Study of multifrequency mobile phone antenna for 4G applications is receiving more and more atten-tion [5–7].However,for the design of the mobile phone internal antenna,it is challenge issue to achieve the impedance matching in multiple service bands and reduce the size.A small size antenna for mobile phone internal equipment is very desirable,but still lacking to date.In this article,a new simple antenna consisting of S-shaped shorted strip and inverted L-shaped shorted strip to cover the LTE bands is presented.The proposed antenna can generate multiple resonant modes with the help of the system ground plane by coupling interactions S-shaped shorted strip and inverted L-shaped shorted strip.Three service bands for 4Gapplication are provided:660–810MHz,2.25–2.85GHz,and 3.28–3.97GHz,which can cover LTE 700(698–787MHz),LTE 2300(2305–2400MHz),and LTE 2500(2500–2690MHz).The proposed antenna only occupies a size of 21315mm 2and is easily printed on the top of an FR4substrate,which makes it suitable for practical personal wireless commu-nication mobile handset applications.Details of the proposed antenna’s design and parameter study are presented and dis-cussed in the following sections.2.ANTENNA CONFIGURATION AND DESIGNFigure 1shows the geometry of the proposed simple antenna with S-shaped shorted strip and inverted L-shaped shorted strip for LTE-band operation in the mobile phone.The proposed antenna is printed on one corner of the bottom edge of the sys-tem circuit board with the radiating elements dimensions of 21315mm 2while the ground plane is printed on the back side of the substrate.In this study,a 0.8-mm-thick FR4substrate of rel-ative permittivity of 4.4,loss tangent of 0.024,size 115350mm 2is used as the main circuit board of the mobile phone.The size of the main circuit board is selected for that of a prac-tical 4-inch smart phone.It is fed by a 50-X mini coaxial line connected to the feeding point (point A)of the driven monopole and the display grounding point (point B).The dimension parameters of the radiating element in its planar structure are shown in Figure 2.The radiating element of the proposed antenna only occupies the area of 21315mm 2,which is much smaller than that of using dual parasitic shorted strips for LTE-band operation in Refs.7]and [8].In this section,the presented antenna with various design parameters were constructed,and the numerical results of the radiation characteristics are presented and discussed.The simu-lated results are obtained using the Ansoft simulation software high-frequency structure simulator (HFSS).Figure 3illustrates the return loss of the proposed antenna when the L 1varies from 12to 16mm.From this figure,one sees that the resonant fre-quency at low band becomes from 0.87,0.81to 0.75GHz;note that the resonant frequency at moderate and high band equals 2.6and 3.5GHz,respectively.Obviously,L 1516mm gives the best resonant frequency at low band (0.75GHz),which meet the LTE 700band.Figure 4depicts the return loss of the proposed antenna with various length of L 3.From this figure,one sees that the highest band resonant center frequency shifts from 4.11to 3.27GHz by increasing L 3from 14to 16mm.Figure 1Conﬁguration of the proposedantennaFigure 2Dimension parameters of the radiating elementsFigure5shows that L4mainly influences the return loss and resonant center frequency.With the decrease of L4,the return loss decreases significantly and resonant center frequency at intermediate band changes from2.49to2.66GHz.Obviously, L4513mm gives the best return loss(237dB)and center fre-quency(2.6GHz).The impedance bandwidth operation is of 2.25–2.85GHz to cover LTE2300and LTE2500service bands.The optimized values of proposed antenna design param-eters are as follows:L521mm,W515mm,W155mm, W251mm,W350.5mm,W451.5mm,W554mm, W654mm,L1516mm,L255mm,L3515mm,and L4513mm.The above antenna dimensions are obtained through simulation using commercial HFSS software.3.EXPRIMENT RESULTS AND DISCUSSIONThe proposed antenna is fabricated on an FR4substrate with thickness of0.8mm,relative permittivity of4.4,and loss tan-gent of0.024.In the experiment for testing the fabricated antenna shown in Figure6,the microstrip feedline is connected to a50-X coaxial cable at point A and point B as shown in the figure.The experimental characterization was performed using an Agilent PNA8362B vector network analyzer.Figure7shows the simulated and measured return loss of the fabricated antenna.Generally,a6-dB return loss is acceptable for mobile phone applications.The simulated results obtained using com-mercial HFSS simulation software show good agreement with the measured data.The impedance matching for frequencies over the three wide operating bands including lower band (0.66–0.81GHz),intermediate band(2.25–2.85GHz),and upper band(3.28–3.97GHz)are better than3:1VSWR or6-dB return loss(see the figure),which is generally used as the design spec-ification for practical internal mobile phone antenna applica-tions.The obtained bandwidth covers LTE700(698–787MHz), LTE2300(2305–2400MHz),and LTE2500(2500–2690 MHz),which can meet4G application.The measured result has slight discrepancy with the simulation due to the limitation of coaxial line connecter and its mechanical tolerance,which have been neglected in our simulations.Figure8shows the measured far field radiation patterns including the copolarization and crosspolarization in the H-plane (x-z plane)and E-plane(x-y plane)at the center frequencies of each low,intermediate and high band,0.75,2.6,and3.5GHz, respectively.The main purpose of the radiation patterns isto Figure4Simulated return loss characteristics of the proposed antennafor various L3.[Colorﬁgure can be viewed in the online issue,which isavailable at]Figure5Simulated return loss characteristics of the proposed antennafor various L4.[Colorﬁgure can be viewed in the online issue,which isavailable at]Figure6Photograph of the fabricated antenna.[Colorﬁgure can beviewed in the online issue,which is available at] Figure3Simulated return loss characteristics of the proposed antennafor various L1.[Colorﬁgure can be viewed in the online issue,which isavailable at ]demonstrate that the antenna actually radiates over three LTEfrequency bands.From Figure8,one can see that the corre-sponding maximum gains are of3.0,4.7,and3.6dBi,respec-tively.It can also be seen that the radiation patterns in x-z planeare nearly omnidirectional for the three frequencies.Both theradiation characteristics and the peak gains are degraded in eachband edge as we expected and are satisfying the gain require-ments of the current mobile phones.4.CONCLUSIONA novel simple monopole antenna with a compact size of21315mm2for4G mobile handset has been presented.Theobtained impedance bandwidth across the operating bands canreach about198/833/327MHz for the LTE bands while thepeak gains are about3.0/4.7/3.6dBi.Good radiation characteris-tics for frequencies over the antenna’s LTE bands have alsobeen obtained,which makes the proposed antenna very promis-ing for practical slim mobile phone applications.Furthermore, Figure7Measured and simulated return loss for the fabricated antennaFigure8Measured two-dimensional radiation patterns for the proposed antenna at(a)0.75GHz,(b)2.6GHz,(c)3.5GHz.[Colorﬁgure can be viewed in the online issue,which is available at ]the presented antenna can be easily fabricated and modified to various4G mobile phones as a compact antenna.ACKNOWLEDGMENTSThis research was partially supported by the National Natural Science Foundation of China(No.61131005,No.61379024), Zhejiang Province Natural Science Fund for Distinguished Young Scientists(LR12F05001),and Zhejiang Provincial Qian-jiang Talent Project(2013R10065).REFERENCES1.S.Zuo,Z.Zhang,and J.Yang,Planar meander monopole antennawith parasitic strips and sleeve feed for DVB-H/LTE/GSM850/900 operation in the mobile phone,IEEE Antennas Wireless propag lett 12(2013),27–30.2.Y.Cui and R.Li,A novel broadband planar antenna for2G/3G/LTEbase stations,IEEE Trans Antennas Propag61(2013),2767–2774.3.Y.Yu,U.Kim,W.Seong,and J.Choi,Design of a coupledline feed structure for the wideband characteristic of a mobileinternal antenna,Microwave Opt Technol Lett55(2013),522–526.4.C.Chang,W.Wei,P.Ma,and S.Huang,Simple printed WWANmonopole slot antenna with parasitic shorted strips for slim mobile phone application,Microwave Opt Technol Lett55(2013),2835–2840.5.G.Zhao,A.Wang,W.Leng,B.Chen,and H.Chen,Widebandinternal antenna with coupled feeding for4G mobile phone,Micro-wave Opt Technol Lett55(2013),513–516.6.C.Yang,Y.Jung,and C.Jung,Octaband internal antenna for4Gmobile handset,IEEE Antennas Wireless Propag Lett10(2011), 817–819.7.J.Lu and Z.Lin,Planar compact LTE/WWAN monopole antennafor tablet computer application,IEEE Antennas Wireless Propag Lett12(2013),147–150,2013.8.K.Wong,W.Woi,L.Chou,WWAN/LTE printed loop tablet com-puter antenna and its body SAR analysis,Microwave Opt Technol Lett53(2011),2912–2919.V C2014Wiley Periodicals,Inc.。

2020CSCO胆道系统肿瘤诊疗指南

中国临床肿瘤学会（CSCO）胆道恶性肿瘤诊疗指南GUIDELINES OF CHINESE SOCIETY OF CLINICAL ONCOLOGY （CSCO）BILIARY TRACT CANCER2020.V1.0中国临床肿瘤学会指南工作委员会组织编写人民卫生出版社中国临床肿瘤学会指南工作委员会组长梁后杰沈锋秦叔逵副组长（以姓氏汉语拼音为序）毕锋戴广海李恩孝刘基巍刘秀峰钦伦秀王理伟朱陵君中国临床肿瘤学会（CSCO）胆道恶性肿瘤诊疗指南2020. V1.0组长梁后杰沈锋秦叔逵副组长毕锋戴广海李恩孝刘基巍刘秀峰钦伦秀王理伟朱陵君秘书组郭婧谢赣丰郑怡专家组成员（以姓氏汉语拼音为序）（*主要执笔人）白苇空军军医大学西京医院毕锋*四川大学华西医院陈骏*南京大学医学院附属鼓楼医院陈小兵河南省肿瘤医院陈志宇陆军军医大学西南医院仇金荣海军军医大学东方肝胆外科医院戴广海*解放军总医院邓薇首都医科大学附属北京友谊医院方维佳*浙江大学附属第一医院顾康生安徽医科大学第一附属医院顾艳宏*江苏省人民医院郭婧*青岛大学附属医院郭增清福建省肿瘤医院何宇陆军军医大学西南医院何义富安徽省肿瘤医院黄云中南大学湘雅医院焦洋安徽医科大学第一附属医院李俊海军军医大学东方肝胆外科医院李勇南昌大学第一附属医院李恩孝*西安交通大学第一附属医院李富宇四川大学华西医院梁后杰*陆军军医大学西南医院廖峰*解放军东部战区总医院刘波山东省肿瘤医院刘宏鸣陆军军医大学特色医学中心刘基巍*大连医科大学附属第一医院刘先领中南大学湘雅二医院刘秀峰*解放军东部战区总医院柳江新疆自治区人民医院娄长杰哈尔滨医科大学附属肿瘤医院卢进四川省肿瘤医院陆明北京大学肿瘤医院陆菁菁*北京和睦家医院栾巍内蒙古自治区人民医院罗嘉湖南省肿瘤医院吕红英青岛大学附属医院马虹*华中科技大学协和医院马惠文重庆市肿瘤医院欧娟娟陆军军医大学西南医院彭永海*解放军联勤保障部队第九〇〇医院钦伦秀*复旦大学附属华山医院秦宝丽辽宁省肿瘤医院秦叔逵南京金陵医院秦艳茹郑州大学第一附属医院邱文生*青岛大学附属医院尚培中陆军第八十一集团军医院沈丽达云南省肿瘤医院石焕山东省肿瘤医院寿佳威浙江大学医学院附属邵逸夫医院滕赞中国医科大学附属第一医院田伟军天津医科大学总医院王斌吉林省肿瘤医院王坚上海交通大学附属第六人民医院王欣云南省第一人民医院王馨厦门大学附属中山医院王阿曼大连医科大学附属第一医院王理伟*上海交通大学医学院附属仁济医院王文玲贵州医科大学附属肿瘤医院吴田田北京大学国际医院吴胤瑛西安交通大学第一附属医院谢赣丰*陆军军医大学西南医院许瑞莲深圳市人民医院殷保兵*复旦大学附属华山医院殷先利湖南省肿瘤医院应杰儿浙江省肿瘤医院臧远胜海军医科大学附属长征医院张倜天津医科大学肿瘤医院张翠英内蒙古自治区人民医院张永杰淮安市第二人民医院赵达兰州大学第一医院郑璐陆军军医大学新桥医院郑怡*浙江大学医学院附属第一医院郑振东解放军北部战区总医院周航遵义医学院附属医院周军*北京大学肿瘤医院周俊同济大学附属东方医院周琪重庆市涪陵中心医院周云河南省人民医院周福祥武汉大学中南医院周建炜河南省人民医院朱青四川大学华西医院朱陵君*江苏省人民医院前言基于循证医学证据，兼顾诊疗产品的可及性，积极吸收精准医学新进展，制定中国常见癌症的诊断和治疗指南，是中国临床肿瘤学会（CSCO）的基本任务之一。

ASTM A890 A890M

Designation:A890/A890M–12Standard Speciﬁcation forCastings,Iron-Chromium-Nickel-Molybdenum Corrosion-Resistant,Duplex(Austenitic/Ferritic)for General Application1This standard is issued under theﬁxed designation A890/A890M;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon(´)indicates an editorial change since the last revision or reapproval.1.Scope*1.1This speciﬁcation covers a group of cast duplex stainless steels(austenitic/ferritic).1.2The duplex stainless steel alloys offer a combination of enhanced mechanical properties and corrosion resistance when properly balanced in composition and properly heat treated. Ferrite levels are not speciﬁed,but these alloys will develop a range of approximately30to60%ferrite with the balance austenite.It is the responsibility of the purchaser to determine which grade shall be furnished depending on design and service conditions,mechanical properties,and corrosion-resistant characteristics.N OTE1—Because of the possibility of precipitation of embrittling phases,the grades included in this speciﬁcation are not recommended for service at temperatures above600ºF[315ºC].1.3The values stated in either SI units or inch-pound units are to be regarded separately as standard.The values stated in each system may not be exact equivalents;therefore,each system shall be used independently of the bining values from the two systems may result in non-conformance with the standard.1.3.1Within the text,the SI units are shown in brackets.2.Referenced Documents2.1ASTM Standards:2A370Test Methods and Deﬁnitions for Mechanical Testing of Steel ProductsA732/A732M Speciﬁcation for Castings,Investment,Car-bon and Low Alloy Steel for General Application,and Cobalt Alloy for High Strength at Elevated Temperatures A781/A781M Speciﬁcation for Castings,Steel and Alloy, Common Requirements,for General Industrial UseE29Practice for Using Signiﬁcant Digits in Test Data to Determine Conformance with SpeciﬁcationsE562Test Method for Determining V olume Fraction by Systematic Manual Point CountE1245Practice for Determining the Inclusion or Second-Phase Constituent Content of Metals by Automatic Image Analysis3.Ordering Information3.1Orders for material to this speciﬁcation shall include the following,as required,to describe the material adequately: 3.1.1Description of casting by pattern or drawing number (dimensional tolerance shall be included on the casting draw-ing),3.1.2Speciﬁcation designation and grade including year of issue,3.1.3Options in the speciﬁcation(See9.1),and3.1.4Supplementary requirements desired,including the standards of acceptance.4.Process4.1The steel shall be made by the electric furnace process with or without separate reﬁning such as argon-oxygen-decarburization(AOD).5.Heat Treatment5.1Castings shall be heat treated in accordance with the requirements in Table1.N OTE2—Proper heat treatment of these alloys is usually necessary to enhance corrosion resistance and in some cases to meet mechanical properties.Minimum heat-treat temperatures are speciﬁed;however,it is sometimes necessary to heat-treat at higher temperatures,hold for some1This speciﬁcation is under the jurisdiction of ASTM Committee A01on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.18on Castings.Current edition approved March1,2012.Published April2012.Originallyapproved st previous edition approved in2010as A890/A890M–10.DOI:10.1520/A0890_A0890M-12.2For referenced ASTM standards,visit the ASTM website,,orcontact ASTM Customer Service at service@.For Annual Book of ASTMStandards volume information,refer to the standard’s Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standard. Copyright©ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959,United States. --``,,,``,,,``,,```,``,,`,`,`,,,-`-`,,`,,`,`,,`---minimum time at temperature and then rapidly cool the castings in order to enhance the corrosion resistance and meet mechanical properties.6.Chemical Composition6.1The steel shall conform to the requirements as to chemical composition prescribed in Table2.7.General Requirements7.1Material furnished to this speciﬁcation shall conform to the requirements of Speciﬁcation A781/A781M,including any supplementary requirements that are indicated in the purchase order.Failure to comply with the general requirements of Speciﬁcation A781/A781M constitutes nonconformance with this speciﬁcation.In case of conﬂict between the requirements of this speciﬁcation and Speciﬁcation A781/A781M,this speciﬁcation shall prevail.8.Repair by Welding8.1The composition of the deposited weld metal may be similar to that of the casting or may be suitably alloyed to achieve the desired corrosion resistance and mechanical prop-erties.8.2Weld repairs shall be subject to the same quality standards as are used to inspect the castings.TABLE1Heat Treatment RequirementsGrade Heat Treatment1B,1C Heat to1900°F[1040°C]minimum,hold for sufficient time toheat casting uniformly to temperature,quench in water or rapidcool by other means.2A Heat to2050°F[1120°C]minimum,hold for sufficient time toheat casting uniformly to temperature,quench in water or rapidcool by other means.3A Heat to1950°F[1070°C]minimum,hold for sufficient time toheat casting uniformly to temperature,quench in water or rapidcool by other means.4A Heat to2050°F[1120°C]minimum for sufficient time to heatcasting uniformly to temperature and water quench,or thecasting may be furnace cooled to1850°F[1010°C]minimum,hold for15min minimum and then water quench.A rapid coolby other means may be employed in lieu of water quench.5A Heat to2050°F[1120°C]minimum,hold for sufficient time toheat casting to temperature,furnace cool to1910°F[1045°C]minimum,quench in water or rapid cool by other means.6A Heat to2010°F[1100°C]minimum,hold for sufficient time toheat casting uniformly to temperature,quench in water or coolrapidly by other means.7A Heat to2065°F[1130°C]minimum,hold for sufficient time toheat casting to temperature,furnace cool to1940°F[1060°C]minimum,quench in water or rapid cool by other means.TABLE2Chemical RequirementsGrade1B A1C B2AType25Cr-5Ni-M0-Cu-N25Cr-6Ni-Mo-Cu-N24Cr-10Ni-Mo-NUNS J93372J93373J93345ACI CD4MCuN CD3MCuN CE8MNComposition:Carbon,max0.040.0300.08Manganese,max 1.0 1.20 1.00Silicon,max 1.0 1.10 1.50Phosphorus,max0.040.0300.04Sulfur,max0.040.0300.04Chromium24.5–26.524.0-26.722.5–25.5Nickel 4.7–6.0 5.6-6.78.0–11.0Molybdenum 1.7–2.3 2.9-3.8 3.0–4.5Copper 2.7–3.3 1.40-1.90...Tungsten.........Nitrogen0.10–0.250.22-0.330.10–0.30Grade3A4A5A B6A B7A CType25Cr-5Ni-Mo-N22Cr-5Ni-Mo-N25Cr-7Ni-Mo-N25Cr-7Ni-Mo-N27Cr-7Ni-Mo-Cu-N UNS J93371J92205J93404J93380ACI CD6MN CD3MN CE3MN CD3MWCuNComposition:Carbon,max0.060.030.030.030.030 Manganese,max 1.00 1.50 1.50 1.00 1.00-3.00 Silicon,max 1.00 1.00 1.00 1.00 1.00 Phosphorus,max0.0400.040.040.0300.030Sulfur,max0.0400.0200.040.0250.020Chromium24.0–27.021.0–23.524.0–26.024.0–26.026.0–28.0Nickel 4.0–6.0 4.5–6.5 6.0–8.0 6.5–8.5 6.0–8.0 Molybdenum 1.75–2.5 2.5–3.5 4.0–5.0 3.0–4.0 2.0–3.5 Copper... 1.00,max...0.5–1.0 1.00,max Tungsten.........0.5–1.0 3.0–4.0Nitrogen0.15–0.250.10–0.300.10–0.300.20–0.300.30–0.40 Boron............0.0010-0.0100 Barium............0.0010-0.0100Ce+La............0.005–0.030A CD4MCu has been removed from the standard.CD4MCuN is an acceptable substitute for CD4MCu.B%Cr+3.3%Mo+16%N$40.C%Cr+3.3(%Mo+0.5%W)+30%N$45.--``,,,``,,,``,,```,``,,`,`,`,,,-`-`,,`,,`,`,,`---8.3When post weld/heat treatment is believed necessary for adequate corrosion resistance or impact resistance,Sup-plementary Requirement S33Post Weld/Heat Treatment shall be included in the purchase order.9.Product Marking9.1Castings shall be marked for material identiﬁcation with the speciﬁcation designation and grade.In addition,the manu-facturer’s name or identiﬁcation mark and the pattern number shall be cast or stamped using low-stress stamps on allcastings.Small-size castings may be such that marking must be limited consistent with the available area.The marking of heat numbers on individual castings shall be agreed upon between the manufacturer and the purchaser.Marking shall be in such position as not to injure the usefulness of the casting.10.Keywords10.1austenite;duplex stainless steel;ferrite;stainless steel;steel castingsSUPPLEMENTARY REQUIREMENTSThe following supplementary requirements shall not apply unless speciﬁed in the purchase order.A list of standardized supplementary requirements for use at the option of the purchaser is included in Speciﬁcation A781/A781M .Those that are ordinarily considered suitable for use with this speciﬁca-tion are listed below by title only.Others enumerated in Speciﬁcation A781/A781M may be used with this speciﬁcation upon agreement between the manufacturer and purchaser.S2.Radiographic Examination S3.Liquid Penetrant Examination S5.Examination of Weld Preparation S6.CertiﬁcationS7.Prior Approval of Major Weld Repairs S9.Charpy Impact Test S10.Hardness Test S12.Test ReportS13.Unspeciﬁed ElementsS31.Estimating Ferrite ContentS31.1Ferrite contents shall be determined by point count (Practice E562),by other quantitative metallographic methods such as image analysis (Practice E1245),by measurement of magnetic response,or by other methods upon agreementbetween the manufacturer and the purchaser.Frequency of testing and location of tests shall be by agreement between the manufacturer and the purchaser.S32.Tensile RequirementsS32.1One tensile test shall be made from each heat and shall conform to the tensile requirements speciﬁed in Table S32.1.Test bars shall be poured in special blocks from the same heat as the castings represented.(See S32.4.)S32.2The bar from which the test specimen is removed shall be heat-treated in production furnaces to the same procedure as the castings it represents.S32.3Test specimens may be cut from heat-treated castings,at the producer’s option,instead of from test bars.S32.4Test coupons may be cast integrally or as separate cast blocks in accordance with Figs.1and 2of Speciﬁcation A781/A781M .Tension coupons shall be machined to the form and dimensions of Fig.4of Test Methods and Deﬁnitions A370,except when investment castings are ordered.When investment castings are ordered,the manufacturer may prepareTABLE S32.1Tensile RequirementsGrade Type2A24Cr-10Ni-Mo-N 3A25Cr-5Ni-Mo-N 4A22Cr-5Ni-Mo-N Tensile strength,ksi [MPa],min 95[655]95[655]90[620]Yield strength (0.2%offset),ksi [MPa],min65[450]65[450]60[415]Elongation in 2in.[50mm],%,min A252525Grade Type5A25Cr-7Ni-Mo-N 6A25Cr-7Ni-Mo-N 7A27Cr-7Ni-Mo-Cu-N1B25Cr-5Ni-Mo-Cu-N 1C25Cr-6Ni-Mo-Cu-N Tensile strength,ksi [MPa],min 100[690]100[690]100,000[690]100[690]100[690]Yield strength (0.2%offset),ksi [MPa],min75[515]65[450]75,000[515]70[485]65[450]Elongation in 2in.[50mm],%,min A1825201625AWhen ICI test bars are used in tensile testing as provided for in this speciﬁcation,the gage length to reduced section diameter ratio shall be4:1.--``,,,``,,,``,,```,``,,`,`,`,,,-`-`,,`,,`,`,,`---test specimens in accordance with S3.2of Speciﬁcation A732/ A732M.Testing shall be in accordance with Test Methods and Deﬁnitions A370.S32.5If any specimen shows defective machining or devel-opsﬂaws,it may be discarded and another substituted from the same heat.S32.6To determine conformance with the tension test requirements,an observed value or calculated value shall be rounded off in accordance with Practice E29to the nearest500 psi[5MPa]for yield and tensile strength and to the nearest1% for elongation and reduction of area.S33.Post Weld/Heat TreatmentS33.1Castings shall be heat-treated after major weld re-pairs,but heat treatment after minor weld repairs is not required except upon agreement between the manufacturer and the purchaser.S33.2Weld repairs shall be considered major in the case of a casting that has leaked on hydrostatic testing or when the depth of the cavity after preparation for repair exceeds20%of the actual wall thickness,or1in.[25mm],whichever is smaller,or when the extent of the cavity exceeds approxi-mately10in.2[65cm2].All other weld repairs shall be considered minor.S33.3Post weld heat treatment shall be in accordance with Table1.S34.Prior Approval of Weld MaterialS34.1The purchaser must give approval of all weldﬁller materials to be used prior to any weld repairs.S35.Heat Treatment of Test MaterialS35.1Test material for each heat shall be heat-treated with the castings it represents.SUMMARY OF CHANGESCommittee A01has identiﬁed the location of selected changes to this standard since the last issue (A890/A890M–10)that may impact the use of this standard.(Approved March1,2012.)(1)Added notes on purchaser responsibility to determinesuitability of the material characteristics and maximum servicetemperature.(2)Added Grade7A.Committee A01has identiﬁed the location of selected changes to this standard since the last issue (A890/A890M–99(2007))that may impact the use of this standard.(Approved April1,2010.)(1)Deleted Grade1A(CD4MCu)ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this ers of this standard are expressly advised that determination of the validity of any such patent rights,and the riskof infringement of such rights,are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed everyﬁve years and if not revised,either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters.Your comments will receive careful consideration at a meeting of theresponsible technical committee,which you may attend.If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards,at the address shown below.This standard is copyrighted by ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959, United States.Individual reprints(single or multiple copies)of this standard may be obtained by contacting ASTM at the aboveaddress or at610-832-9585(phone),610-832-9555(fax),or service@(e-mail);or through the ASTM website().Permission rights to photocopy the standard may also be secured from the ASTM website(/COPYRIGHT/).--``,,,``,,,``,,```,``,,`,`,`,,,-`-`,,`,,`,`,,`---。

中科院海洋所博士笔试

中科院海洋所博士笔试英文回答：The research topic for my doctoral dissertation is the development of a novel optical imaging system for the non-invasive detection of early-stage neurodegenerative diseases. This system will utilize advanced optical techniques, such as multiphoton microscopy and optical coherence tomography, to image the morphological and functional changes in the brain that are associated with the onset of neurodegenerative diseases. The goal of this research is to develop a diagnostic tool that can be used to identify and monitor these diseases at an early stage, when treatment is most effective.My research will focus on the development of newoptical imaging techniques that can provide high-resolution images of the brain. These techniques will be used to image the microstructural and functional changes that occur in the brain during the early stages of neurodegenerativediseases. I will also develop image processing and analysis algorithms to extract quantitative information from the images that can be used to diagnose and monitor these diseases.The development of a non-invasive optical imagingsystem for the early detection of neurodegenerativediseases has the potential to revolutionize the way these diseases are diagnosed and treated. This system could provide a much earlier and more accurate diagnosis of these diseases, which could lead to more effective treatment and improved patient outcomes.中文回答：我的博士论文研究课题是开发一种用于无创检测早期神经退行性疾病的新型光学成像系统。

SCI科技论文写作常用句型大全

一．好的论文题目是成功的一半好的论文，每一个部分都需要精雕细琢。

我们先来看看Science, Nature 子刊上用的都是些什么题目，到底这些题目暗含哪些玄机？以下是从2016年发表的论文中随机挑选的一些题目，我将其做了一下简单的分类：?reduction1. Water splitting–biosynthetic system with CO2efficiencies?exceeding?photosynthesis. (Science, 2016, 352, 1210)类似: Scalable water splitting on particulate photocatalyst sheets with a solar-to-hydrogen energy conversion efficiency?exceeding?1%?(Nature Materials 2016,15,611-615)这种题目适合哪类文章？适合于那种性能极其显着的文章（可以创纪录的文章），比如说Nocera et al. 的?Science, 2016, 352, 1210，直接与光合作用进行对比，给人的震撼是非常强的。

这种对比效果能够一下子抓住人们的眼球，吸引着读者进行阅读。

要点：使用这样的题目首先你的实验结果得够牛，你对于实验结果要足够自信，对于背景知识的了解得要足够深。

因为取这样的题目意味着你要真正达到了某一个高度。

如果明明有很多大海在那里，你个小池塘和小水坑进行比较，那么会闹笑话的。

2.1 Quantifying?the promotion of Cu catalysts by ZnO for methanol synthesis (?Science,2016, 352, 969-974.)2.2?Exploring?the origin of high optical absorption in conjugated polymers. (Nature Materials 2016,?DOI:?10.1038/nmat4645?)2.3 Promoting?solution phase discharge in Li–O2 batteries containing weakly solvatingelectrolyte?solutions (Nature Materials 2016, DOI: 10.1038/nmat4629)2.4 Reconstructing?solute-induced phase transformations within individual nanocrystals (NatureMaterials 2016,?doi:10.1038/nmat4620)2.5 Tailoring?the nature and strength of electron–phonon interactions in the SrTiO3(001) 2D electron?liquid (Nature Material, 2016, doi:10.1038/nmat4623)我简单地检索了下Nature Materials上面的文章题目，发现这种类型的题目真的非常多。

Grid cells and cortical representation

Idealists argue that the hexagonal rooms are the necessary shape of absolute space, or at least of our perception of space. The Library of Babel, Jorge Luis Borges The nervous system has evolved to enable adaptive decision making and behaviour in response to changes in the internal and external environment. To permit adaptive responses, nervous systems recreate proper-ties of the internal or external world in activity pat-terns that are referred to as neural representations. Representations can be thought of as dynamic clus-ters of cells, the activity patterns of which correlate with features of the outside world. By recreating the environment in a language that is suitable for brain computation, representations are thought to medi-ate the selection of appropriate action in response to stimulus configurations in the animal’s environment. Given the importance of internal representations in guiding behaviour, understanding their mechanisms has become one of the central goals of contemporary neuroscience.Representations have been studied at multiple lev-els, from the earliest stages of sensory systems, where sensory maps reproduce the spatial organization of the sensory receptors, to the highest levels of associa-tion cortices, where representations bear little resem-blance to activation patterns in the receptor population (BOX 1). The mechanisms underlying the formation of representations at the bottom of the representational hierarchy (near the sensory receptor populations) have been explored extensively, particularly in the visual system. Much less is known about how representations form at higher levels, where representations depend more strongly on intrinsic cortical computations. The aim of this Review is to discuss mechanisms of neuralrepresentation in the medial entorhinal cortex (MEC), which is near the apex of the cortical hierarchy 1, using well-studied representations in the primary visual cortex (V1) as a reference.Place cells and grid cellsThe MEC and the hippocampus are a part of the brain’s neural map of external space 2–4 (BOX 2). Multiple func-tional cell types contribute to this representation. The first spatial cell type to be discovered was the place cell 5,6. Place cells are hippocampal cells that fire selec-tively when animals are at certain locations in the envi-ronment. The description of place cells in the 1970s was followed, more than 30 years later, by the discovery of grid cells , one synapse upstream of place cells, in the MEC 7–9. Grid cells are place-selective cells that fire at multiple discrete and regularly spaced locations 7. These firing locations form a hexagonal pattern that tiles the entire space that is available to the animal 8 (FIG. 1a). Whereas ensembles of place cells change unpredictably from one environment to the next 10,11, the positional relationship between grid cells is maintained, reflecting the structure of space independently of the contextual details of individual environments 12. The rigid struc-ture of the grid map, along with its spatial periodicity, points to grid cells as a part of the brain’s metric for local space 4,12.Place cells and grid cells were discovered in rats, but similar cells have subsequently been reported in mice 13–15, bats 16,17, monkeys 18–21 and humans 22,23, although the bulk of research on entorhinal–hippocampal spa-tial representation is still carried out using rodents. The strong correspondence in each species between entorhinal–hippocampal firing patterns and a measur-able property of the external world — the location of1Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and T echnology, 7491 T rondheim, Norway.2Institute of Neuroscience, University of Oregon, Eugene, Oregon 97403-1254, USA. 3Max Planck Institute of Neurobiology, AmKlopferspitz 18, 82152 Planegg-Martinsried, Germany.Correspondence to E.I.M. e-mail: edvard.moser@ ntnu.nodoi:10.1038/nrn3766 Published online 11 June 2014Entorhinal cortexAn interface between the three-layered hippocampal cortex and six-layeredneocortex. It provides the main cortical input to the dentate gyrus.Place cellA type of hippocampal neuron that typically has a singleenvironmentally specific spatial receptive field. There is no discernible relationship between firing patterns in different environments.Grid cells and cortical representationEdvard I. Moser 1, Yasser Roudi 1, Menno P . Witter 1, Clifford Kentros 1,2, T obias Bonhoeffer 1,3 and May-Britt Moser 1Abstract | One of the grand challenges in neuroscience is to comprehend neural computation in the association cortices, the parts of the cortex that have shown the largest expansion and differentiation during mammalian evolution and that are thought to contribute profoundly to the emergence of advanced cognition in humans. In this Review, we use grid cells in the medial entorhinal cortex as a gateway to understandnetwork computation at a stage of cortical processing in which firing patterns are shaped not primarily by incoming sensory signals but to a large extent by the intrinsic properties of the local circuit.Neuroscience VS 1VI OI H OS 23DaLateral Rostral30 °LStimulus orientationCb Db Grid cellsParahippocampal neurons that have regularly repeatinghexagonally spaced receptive fields. Co-activity patternsremain largely the same across different environments.the animal — makes the spatial representation circuit a powerful experimental model system for understanding neural computation at the highest levels of the association cortices, many synapses away from sensory receptors and motor outputs.Grid cells and sensory inputsThe defining feature of grid cells is their hexagonal fir-ing structure 8. However, grid cells differ in grid spacing (the distance between grid fields), grid orientation (the rotation of grid axes) and grid phase (the x –y locations. The visual stimulus used in thisCA1 SubiculumMEC Layer VI Layer V Layer III Layer IIHippocampalof firing vertices)8,24(FIG. 1b). Grid cells exhibit vari-able degrees of asymmetry24,25, and periodicity may beexpressed more strongly along one axis of the triangu-lar grid than the two others26. Collectively, the variety ofgrid cells defines a map of the animal’s relative position inthe environment7,12. Because grid cells differ in spacing, each place in the local environment is associated with a unique combination of active cells, enabling neurons with access to this combined activity to faithfully read out the animal’s location.The map of grid cells is dynamic, in the sense that acti-vation is driven by the animal’s movement in the envi-ronment3,8. For grid activity to be updated in accordance with ongoing movement, grid cells must have access to sensory signals that correspond to the animal’s change in location. Only a few types of sensory input are suf-ficiently continuous to enable smooth translation of the grid representation. Such inputs include proprioceptive and kinaesthetic feedback as well as vestibular signals and optic flow. Consistent with a primary role for self-motion inputs and a secondary role for inputs from stationary cues, grid cells retain their hexagonal firing pattern after removal of visual or olfactory landmarks8,12. Pairs of grid cells tend to maintain spatial firing relationships across environments, independently of landmark identities12, as expected if the algorithm were based on self-motion.A strong dependence on motion cues might imply a role for grid cells in representations based on path integration, a process whereby animals keep track of their position by integrating linear and angular run-ning speed over time to yield spatial displacement rela-tive to a reference position (for example, the starting position of a path)27–29. Both place cells and grid cells express outcomes of path integration, in the sense that firing fields can often be related to distance of movement from a reference position rather than to inputs from stationary visual cues30–34. Recent work has identified a dedicated cell population for linear representation of running speed within the MEC35. By integrating speed over time, these speed cells may provide grid cells with information about changes in position. A role for speed cells and grid cells in path integration is consistent with the observation that rats with MEC lesions fail to navigate back to a refuge under conditions in which only self-motion cues are informative36,37. However, mechanisms for path inte-gration may exist in multiple brain circuits, as sug-gested by the fact that, in humans, unlike rats, simple self-motion-based navigation is spared by lesions that include the entorhinal cortex37,38.Path integration can only be used to calculate dis-placement from fixed reference positions. Stationary cues are required to associate path-integration coordi-nates with absolute position. The fact that grid phase and grid orientation remain stable across test sessions8, and that grid fields rotate along with external reference points in cylindrical environments8, suggests that grid coordinates are anchored to the external environment. Experiments in compartmentalized mazes suggest that grid maps anchor at many locations and often near sali-ent environmental features32. Frequent anchoring may prevent drift owing to accumulation of path-integration error39. However, the frequency at which grid maps are updated is not known. Grid maps may be re-anchored at regular intervals — for example, on individual cycles of the local theta rhythm — or resetting may occur in response to specific cues in the environment.| Neuroscienceb aGrid scaleGrid orientation Grid phaseG r i d s p a c i n g (c m )Dorsoventral location (rank-ordered)01020Rat: 15708Dorsoventral location (rank-ordered)1020TT9G r i d s p a c i n g (c m )1201003001020TT10Rat: 15314cP r o b a b i l i t ydTT5TT3Theta rhythmOscillatory activity in the range of 6–10 Hz in the local field potential of the hippocampus. It is produced by large and widespread ensembles of hippocampal neurons that oscillate in synchrony.Salt-and-pepper-like organizationCortical architecture in which single cells are tuned for the orientation of a stimulus but show no particular order in their arrangement. This arrangement is seen in the rodent visual cortex.Architecture of the grid mapAlthough grid fields are modulated by sensory inputs, such inputs are not sufficient to explain how the grid pattern itself is formed. The hexagonal grid pattern is not reflected in any of the polysynaptic sensory inputs to the grid cells, suggesting that it arises intrinsically in the MEC or the wider parahippocampal circuit of which the MEC is a part. This possibility justifies a closer look at the functional architecture of the grid cell network.The organization of grid cells is partly topographic and partly non-topographic 8. Grid scale shows topographic organization in the sense that grid cells with small fields and small interfield distances predominate in the dorsal part of the MEC. At more ventral levels, cells with larger grid scales predominate 7,24,40. By contrast, the phase of the grid pat-tern exhibits no discernible large-scale topography 8. Local ensembles of grid cells apparently cover the entire range of grid phases at all MEC locations. The distribution of grid phases is similar to the interspersed or salt-and-pepper-like organization of response properties in several sensory corti-ces, such as odour representations in the piriform cortex 41,42 or orientation maps in the visual cortex of rodents 43–45. However, fine-scale topography of grid phase has not been ruled out. Samples of simultaneously recorded cells are generally small, and the resolution of tetrode recordings does not enable anatomical mapping at a scale of less than 50–100 micrometres 46. Thus, approaches with better ana-tomical resolution need to be developed before estimates of the functional microarchitecture can be made 47,48.The lack of grid-phase topography does not rule out the presence of discrete cell assemblies with unique func-tions. Recent recordings from up to almost 200 grid cells per animal have suggested, in agreement with a small sample of data from an earlier study 25, that grid cells cluster into modules of cells with similar grid scale, grid orientation and grid asymmetry but different grid phase 24 (FIG. 1c). Modules with short grid wavelengths (spacing) predominate at the dorsal end of the MEC. Larger-scale modules are added successively towards the ventral MEC without discarding the shorter wavelengths. The increase in grid scale is discontinuous. If grid modules are sorted by wavelength, from short to long, the average wavelength increases from one module to the next by a factor of 1.4, as in a geometric progression (FIG. 1d). At the same time, the number of cells per module decreases.Figure 1 | Basic properties of grid cells. a | Spatial firing pattern of a grid cell from layer II of the rat medial entorhinal cortex (MEC). The grey trace shows the trajectory of a foraging rat in a 2.2 m wide square enclosure. The locations at which the grid cell spikes are superimposed on the trajectory are shown in black. Each black dot corresponds to one spike. Note the periodic hexagonal pattern of the firing fields of the grid cell. b | Cartoons of firing patterns of pairs of grid cells (shown in blue and green), illustrating the differences between grid scale, grid orientation and grid phase. Lines in left and middle panels indicate two axes of the grid pattern (which define grid orientation); crosses in the panel on the right indicate grid phase (x –y location of grid fields). c | Modular organization of the grid scale. Grid spacing is shown as a function of position along the recording track in the MEC, with cells (represented by grey circles) rank-ordered from dorsal to ventral and one panel per tetrode (TT). On each tetrode, grid spacing increases in discrete steps. d | A schematic showing that the increase in grid scale across modules follows a geometric progression rule. From one module to the next, average grid scale increases by a constant factor (1.4 in this case). Part a is reprinted from Moser, E. I. & Moser, M. B. Grid cells and neural coding in high-end cortices. Neuron 80, 765–774 (2013)229. Copyright (2013), with permission from Elsevier. Part c from REF . 24, Nature Publishing Group.Head direction cells Neurons found throughout parahippocampal areas and in other brain regions (for example, the anterior thalamus) for which the primary feature of the receptive field is the direction in which the animal’s head is pointing.Attractor networkA network with one or more stable firing-rate pattern that is stored in the structure of the synaptic connectivity.Theoretical analyses suggest that such an organizationmay be optimal for obtaining maximal spatial resolutionfrom a minimal number of grid cells49,50. The emergenceof an architecture that maximizes information from alimited pool of neurons is reminiscent of the balancebetween the number of on and off cells in the retina,which has been shown to match the statistical structureof common visual scenes51.The functional coherence of grid cells within mod-ules and their separation from grid cells in other mod-ules raise the possibility that grid networks consist ofanatomically overlapping subnetworks that exhibitstrong intrinsic coupling but weaker coupling to othersubnetworks.Key questions for the future will be todetermine which cells wire together in such networks,at which developmental stage this wiring takes placeand how cells of the same network find each other.For functional maps in the visual cortex, there is moreinformation on these questions: it is now reasonablywell established that activity-dependent mechanismsare involved in forming the map or, in the special caseof rodents, connecting cells with particular responseproperties52–54. The basic organization of connectionsin the visual pathway is established before visual expe-rience as a result of spontaneous correlated activity(retinal and cortical waves)55–58 or by means of gap-junction coupling of clonally related neurons at prenataldevelopmental stages59,60. It remains unknown whetherthe developmental processes underlying the modu-lar architecture of grid cell ensembles rely on similarmechanisms.The entangled nature of grid modules differs from theorganization of representations for continuous variablesin some other cortical systems. For example, in the visualcortex of cats and monkeys, orientation-selective cells areorganized into continuous pinwheel-like structures thatmap orientations successively through the 180-degreeorientation cycle61. Orientation maps in these species aresmooth except at the very centre of the pinwheel62,63 and atthe border between direction-sensitive domains43. Becauseorientation is circular, a pinwheel-like arrangement maybe required for optimal continuity. Other parameters suchas ocular dominance, disparity, spatial frequency and, ofcourse, position in space are mapped continuously acrossthe entire cortical surface64–70. A notable exception is thesalt-and-pepper-like organization of orientation tuningin the rodent visual cortex43–45. Plausible explanations forthis exception lie in the relative scale of the cortical area,the magnification factor and the receptive field scatter,which make an interspersed organization a necessityif all stimulus para m eters are to be represented in eachregion of visual space. If a mouse had functional columnsthe size of those in cats, and not a salt-and-pepper-likeorganization, it would only see one stimulus feature — forexample, one orientation — in any portion of the visualfield. We can only speculate whether a similar explana-tion may hold true for the salt-and-pepper-like repre-sentation of grid phase in the MEC, whether grid phasewould be represented topographically in mammals withlarger MECs and whether topographic representationmatters for the way animals perceive space.Finally, MEC networks do not only consist of gridcells. Grid cells intermingle with head direction cells— cells that fire only if the rat’s head is pointing in acertain direction relative to external cues. These cellswere first found in the adjacent presubiculum71,72 butwere subsequently also recorded in the MEC9. Gridcells and head direction cells further intermingle withborder cells — cells that fire exclusively when the ratis close to a salient border of the environment, such asthe wall of a recording enclosure or the edge of a plat-form73,74 — as well as the aforementioned speed cells,the firing rates of which increase monotonically withrunning speed, independently of the rat’s location orhead direction35. Cells with border-determined firingproperties also exist in the subiculum75,76. Grid cells,head direction cells, border cells and speed cells arefunctionally discrete populations but coexist with cellswith conjunctive properties9,35,74. The mixture of func-tional cell types in the MEC has an interesting analogyin the visual system in visual area V2 — and to a lesserextent V1 — where, at least in primates, cells coding forcolour, disparity, orientation, motion, spatial frequencyand other properties coexist, albeit to a certain extentin certain compartments77. In the visual cortex, as inthe MEC, functional properties are distributed ontodiscrete but intermingled cell types.Attractor networks and mechanismsSeveral properties of grid cells point to local circuitcomputation as the source of the grid pattern. Withinmodules of grid cells, cell assemblies respond withcoherent changes in grid phase, grid orientation andgrid scale when the animal is brought to a differentenvironment12,24 or following interventions that changethe scale of the grid, such as exposure to an unfamil-iar environment25,78,79 or compression of the recordingenclosure24,25. In each case, the relationship between fir-ing fields of cell pairs is conserved despite major changesin the properties of individual cells and without anyobvious relationship to sensory inputs78. These observa-tions are consistent with the idea that grid cells operateas ensembles of interconnected neurons whose activitypatterns move across continua of attractor states (BOX 3;FIG. 2). Attractor models provide powerful workinghypotheses for grid cells, although alternative mecha-nisms, such as interference between theta-frequencymembrane potential oscillations80–82, have also beenexplored4,83. Oscillatory interference models of grid cellshave guided some of the most important experimentalstudies on grid cells, but there is mounting experimentalevidence against simple versions of these models (BOX 4).The focus of this article is therefore on attractor network-based mechanisms.The idea of an attractor network is one of the mostinfluential concepts in theoretical systems neurosci-ence84–87. Attractor networks can be traced back toDonald Hebb88 who argued that co-firing neuronsshould be more strongly connected to each other than tothe rest of the network, thus forming so-called Hebbiancell assemblies. Activating a subset of the neurons insuch an assembly will lead to activation of the rest. TheContinuous attractorAn attractor network in which the collection of attracting points form not a discrete set but a continuum (a ring or a sheet).Mexican hat connectivity The connectivity of networks in which neurons are arranged on a ring or sheet such that the excitatory connections of each neuron decrease progressively with distance, whereas inhibitory connections increase in strength.Stellate cells Morphologically defined as cells with a round soma and dendrites radiating from it in all directions. In the medial entorhinal cortex, stellate cells are the main origin of the projection to the dentate gyrus and CA3.activation may self-sustain by reverberation of activitythrough the strong connections that link neurons withinthe Hebbian assembly.In a seminal theoretical study that paved the way forthe continuous attractor concept, Amari89 showed thatstable localized activity patterns can be maintained innetworks in which neurons are arranged on a ring, suchthat the excitatory connections of each neuron decreaseprogressively with distance on the ring, whereas inhibi-tory connections increase (Mexican hat connectivity).Since this study, continuous attractors have been used tomodel various sensory and non-sensory processes, rang-ing from motor-cortex representations of movement tra-jectories90, orientation selectivity in V1 (REFS 91,92), eyeposition93, directional tuning of head direction cells94,95and the position of an animal in space, as represented bythe firing of hippocampal place cells87,96–99.The fact that grid cells maintain their activity patternafter removal of light or other sensory stimuli points to aself-sustaining mechanism8. Not surprisingly then, soonafter the discovery of grid cells, several continuous attrac-tor models were introduced to explain the formation ofspatially periodic firing3,100,101(FIG. 2). All of these mod-els have two stages. First, cells are arranged on a matrixaccording to grid phase. Localized activity (a ‘bump’) isformed when the network has Mexican hat connectiv-ity; that is, cells with similar grid phases are connectedthrough excitatory connections, or they receive less inhi-bition than those with larger phase differences, whichalways inhibit each other (FIG. 2a,b). Bumps can be formedat multiple network locations, with competitive inter-actions leading to the formation of a hexagonal bumppattern on the network array100,101, or the bump can begenerated at a single location, with periodic firing emerg-ing when the activity bump returns to the same locationin a toroidal matrix3,102. In either case, once local activityis generated, the bump is moved by path integration inresponse to asymmetrical speed and direction inputs tothe grid cells, mirroring a mechanism that was originallyproposed for head direction cells95. When the bump fol-lows the animal’s movement, activity is expressed as agrid pattern in each individual cell.Continuous attractor models with Mexican hat con-nectivity were able to produce grid patterns, but it wassoon found that these models relied on connectivitymatrices that were different from those of key circuits ofthe MEC. The prime challenge is the almost complete lackof excitatory connections between layer II stellate cells, thecell type containing the largest number of grid cells andthe most regular grid patterns9,26,103–105. Paired recordingshave shown that excitatory connections are nearly absentamong stellate cells in adult animals and that stellate cellsare instead strongly connected through fast-spiking inhib-itory interneurons106–108. The inhibition between pairs ofstellate cells seems to be consistent in magnitude — thatis, all-or-none107.In response to the lack of excitatory connectionsbetween stellate cells, it was shown that attractor modelscan function with only inhibitory interconnections107–109(FIG. 2c–f). In the presence of external excitatory drive,neural activity in an inhibitory network self-organizedinto a stable hexagonal pattern. Competitive inhibitoryinteractions drove activity to maximally spaced posi-tions. As in the earlier excitatory models, a path-inte-gration mechanism could be used to move the activitybumps across the neuronal lattice in accordance withthe animal’s movement. The emergence of grid patternsin purely inhibitory networks has also been shown in aprevious study of Mexican hat connectivity in whichinhibition decreased progressively as grid phasesbecame more similar101. The dependence on tonic exter-nal excitatory drive predicted by these models has beenverified in a study in which hippocampal projectionsto the MEC were silenced by infusion of a GABAergicagonist in the hippocampus109. Infusions led to substan-tial drops in the firing rates of grid cells, accompaniedby a progressive loss of grid structure and the appear-ance of directional tuning, as expected when residualexternal inputs take over as determinants of grid cellfiring. Similar disruptions of grid cell firing have beenobserved under other conditions that reduce excitatoryinput to grid cells110,111.The relationship between external excitatory inputand grid structure verifies one prediction of the inhibi-tory models but far from proves any of them. Thesemodels demonstrate that inhibitory connections, suchas those that connect layer II stellate cells, are sufficientfor activity to self-organize into a hexagonal pattern.However, whether this actually is the mechanism of gridcell formation remains to be determined. Per today, in|Neuroscience 0 ms 20 ms40 ms60 ms 100 ms 500 msW 0 = –0.01W 0 = –0.02W 0 = –0.04R = 10R = 15R = 20Strong excitatory inputWeak excitatory inputcdefbPhase diﬀerencePhase diﬀerencePhase diﬀerencethe absence of further theoretical development and new experimental data, the high demands that attrac-tor models put on network connectivity disallow them to be adopted as straightforward explanations of grid cells (BOX 3).Assumptions about recurrent connectivityAttractor models of grid cells require neurons to be connected to each other, directly or indirectly, by way of synaptic weights that depend on the phase differ-ence between neurons 3,100,101,107. Whether developmen-tal processes allow for the complexity of such a wiring scheme is an open question. The salt-and-pepper-like organization of the grid network 8 implies that prefer-ential coupling between phase-matched cells cannot be obtained merely by letting cells connect to their nearest neighbours.One possibility is that grid cells overcome the lack of topography by connecting, directly or indirectly, to cells with similar grid phases irrespective of distance. There is some precedence for connectional specificitybetween distributed but functionally similar neurons in V1 of the visual cortex, where cells that code for spe-cific orientations are frequently connected, whereas cells with different orientation preferences are con-nected more rarely 112–115. If cells with similar grid prop-erties wire together similarly in the MEC, how could they find each other? A study by Li et al.59 used in utero electroporation to label cells from one developmental clone in V1. At adult age, sister neurons from this clone were not only more strongly connected but also more similarly tuned for orientation and direction than ran-domly selected neighbouring neuron pairs. These neu-rons were initially connected by gap junctions, which later gave way to chemical synapses. We do not know whether connectional topography between phase-matched cells within modules in the MEC has a similar developmental origin.The development of lateral connectivity becomes simpler if the connectivity problem is reduced from two dimensions to one. This has been suggested in a two-step model by Grossberg and colleagues 116,117. In theFigure 2 | Excitatory and inhibitory attractor models for grid cells. a –c | A variety of connectivity patterns have beenused in attractor models of grid cells to generate hexagonal firing patterns. These include the Mexican hat connectivity used by Fuhs and Touretzky 100 (part a ), the Mexican hat-like connectivity of Burak and Fiete 101 (part b ) and the step-like inhibitory connectivity used by Couey et al.107 (part c ). The connectivity patterns differ in the complexity of the phase dependence of the synaptic weights. In models with Mexican hat connectivity, cells have progressively decreasing excitatory connections combined with increasing inhibitory connections, whereas the Mexican hat-like connectivitymodel and the step-like connectivity model use purely inhibitory connections, although the inhibitory fields have different shapes. All three connectivity patterns produce a hexagonal grid pattern. d | The step-like connectivity model leads to the spontaneous formation of a hexagonal grid pattern. Successive sheets illustrate the network at different developmental stages (0 to 500 ms), with individual pixels corresponding to individual neurons and neurons arranged according to grid phase in each sheet. Activity of neurons is colour-coded, as indicated by the scale bar. Connection radii R of two example neurons are shown as white and green circles (diameter 2R ). e | Single-neuron activity (red dots) in a circular arena from the simulation in part d . W 0 is the strength of the inhibitory connectivity. It can be seen that W 0 and R control the size of the grid fields and their spacing. f | External excitatory drive is necessary for grid formation. Spike distribution plots (on the left, as in part e ) and directional tuning curves (firing rate as a function of direction, on the right) with strong excitatory output and weak excitatory output. When the external input drops below a critical amount, the activity on the neuronal sheet is vulnerable to distortions, and the hexagonal structure is not detectable in time-averaged plots. At the same time, head direction input becomes the dominant source of input and cells become directional. Parts d and e from REF . 107, Nature Publishing Group. Part f from REF . 109, Nature Publishing Group.。

SPS磁盘产品说明书

SPS DISKS- For in vitro use only - Catalogue No. DS65Our SPS Disks can be used for the presumptive identification of Peptostreptococcus anaerobius based on its sensitivity to sodium polyanetholsulphonate (SPS).Studies performed by Wideman et al. and Graves et al. showed that all strains of Peptostreptococcus anaerobius are inhibited by SPS, while other Gram-positive cocci are resistant to SPS. The identification of P. anaerobius is significant since Wideman et al. found that Peptostreptococcus anaerobius may account for one-fifth to one-third of all Gram-positive cocci encountered in clinical specimens. Our SPS Disks contain 1-mg of sodium polyanetholsulphonate and when used as recommended all strains of Peptostreptococcus anaerobius give zones of inhibition ranging from 12 to 30-mm. Recommended Procedure1.Obtain a pure, overnight culture of the testorganism and make an inoculum suspension equivalent to a 0.5 McFarland standard.2.Swab or streak a sample of the suspension onto anon-selective anaerobic blood agar plate or Wilkins-Chalgren Anaerobic Plate in three directions to give a heavy confluent growth.3.Aseptically place a SPS Disk on the agar surface.4.Incubate anaerobically at 35°C for 48 hours.5.Measure the zone of inhibition around the disk tothe nearest millimeter.Interpretation of ResultsA zone of inhibition ≥12-mm indicates SPS sensitivity (S), while a zone of inhibition <12-mm indicates resistance (R) to SPS.Additional biochemical and/or serological tests should be performed on isolated colonies from pure culture in order to complete identification. •Some strains of P. micros are sensitive to SPS. Microscopic differentiation is possiblesince P. micros appear as tiny cocci whereascells of P. anaerobius appear as largecoccobacilli•To ensure the accuracy of the observed results, always run positive and negativecontrols along with the test organismQuality ControlOrganism Expected Results Peptostreptococcus anaerobiusATCC 27337SSPS-sensitivePeptostreptococcus asaccharolyticusATCC 29743RSPS-resistant Storage and Shelf LifeOur SPS Disks should be stored at 4°C to 8°C, and protected from light. Under these conditions they have a shelf life of 26 weeks from the date of manufacture.References1.Balows A, Hausler WJ Herman KL et al.Manual of clinical microbiology. 5th ed.Washington, DC: ASM, 1991.2.Wideman PA, Vargo VL, Citronbaum D andFinegold SM. J. Clin. Micro. 4 (1976).3.Graves MH, Morello JA and Knocka FE.Appl. Microbiol. 27 (1974).Original: September 2000Revised / Reviewed: October 2014。

APL Nanoscale thermal transport. II. 2003–2012

Nanoscale thermal transport. II. 2003–2012David G. Cahill, Paul V. Braun, Gang Chen, David R. Clarke, Shanhui Fan, Kenneth E. Goodson, Pawel Keblinski, William P. King, Gerald D. Mahan, Arun Majumdar, Humphrey J. Maris, Simon R. Phillpot, Eric Pop, and Li ShiCitation: Applied Physics Reviews 1, 011305 (2014); doi: 10.1063/1.4832615View online: /10.1063/1.4832615View Table of Contents: /content/aip/journal/apr2/1/1?ver=pdfcovPublished by the AIP PublishingArticles you may be interested inA transition in mechanisms of size dependent electrical transport at nanoscale metal-oxide interfacesAppl. Phys. Lett. 103, 252106 (2013); 10.1063/1.4851937Nanoscale spatial resolution probes for scanning thermal microscopy of solid state materialsJ. Appl. Phys. 112, 114317 (2012); 10.1063/1.4767923Thermal transport in nanoclustersAppl. Phys. Lett. 98, 193107 (2011); 10.1063/1.3590265Stochastic thermal transport of nanoparticle suspensionsJ. Appl. Phys. 100, 043507 (2006); 10.1063/1.2245203Nanoscale thermal transportJ. Appl. Phys. 93, 793 (2003); 10.1063/1.1524305APPLIED PHYSICS REVIEWSNanoscale thermal transport.II.2003–2012David G.Cahill,1,a)Paul V .Braun,1Gang Chen,2David R.Clarke,3Shanhui Fan,4Kenneth E.Goodson,5Pawel Keblinski,6William P .King,7Gerald D.Mahan,8Arun Majumdar,9Humphrey J.Maris,10Simon R.Phillpot,11Eric Pop,12and Li Shi 131Department of Materials Science and Engineering and the Frederick Seitz Materials Research Laboratory,University of Illinois,Urbana,Illinois 61801,USA 2Department of Mechanical Engineering,MIT,Cambridge,Massachusetts 02139,USA 3School of Engineering and Applied Sciences,Harvard University,Cambridge,Massachusetts 02138,USA 4Department of Electrical Engineering,Stanford University,Stanford,California 94305,USA 5Department of Mechanical Engineering,Stanford University,Stanford,California 94305,USA 6Department of Materials Science and Engineering,Rensselaer Polytechnic Institute,Troy,New York 12180,USA 7Department of Mechanical Sciences and Engineering,University of Illinois,Urbana,Illinois 61801,USA 8Department of Physics,Penn State University,University Park,Pennsylvania 16802,USA 9Department of Mechanical Engineering,University of California,Berkeley,California 94720,USA 10Department of Physics,Brown University,Providence,Rhode Island 02912,USA 11Department of Materials Science and Engineering,University of Florida,Gainseville,Florida 32611,USA 12Department of Electrical and Computer Engineering,University of Illinois,Urbana,Illinois 61801,USA 13Department of Mechanical Engineering,University of Texas,Autin,Texas 78712,USA(Received 6April 2013;accepted 7August 2013;published online 14January 2014)A diverse spectrum of technology drivers such as improved thermal barriers,higher efﬁciency thermoelectric energy conversion,phase-change memory,heat-assisted magnetic recording,thermal management of nanoscale electronics,and nanoparticles for thermal medical therapies are motivating studies of the applied physics of thermal transport at the nanoscale.This review emphasizes developments in experiment,theory,and computation in the past ten years and summarizes the present status of the ﬁeld.Interfaces become increasingly important on small length scales.Research during the past decade has extended studies of interfaces between simple metals and inorganic crystals to interfaces with molecular materials and liquids with systematic control of interface chemistry and physics.At separations on the order of $1nm,the science of radiative transport through nanoscale gaps overlaps with thermal conduction by the coupling of electronic and vibrational excitations across weakly bonded or rough interfaces between materials.Major advances in the physics of phonons include ﬁrst principles calculation of the phonon lifetimes of simple crystals and application of the predicted scattering rates in parameter-free calculations of the thermal conductivity.Progress in the control of thermal transport at the nanoscale is critical to continued advances in the density of information that can be stored in phase change memory devices and new generations of magnetic storage that will use highly localized heat sources to reduce the coercivity of magnetic media.Ultralow thermal conductivity—thermal conductivity below the conventionally predicted minimum thermal conductivity—has been observed in nanolaminates and disordered crystals with strong anisotropy.Advances in metrology by time-domain thermoreﬂectance have made measurements of the thermal conductivity of a thin layer with micron-scale spatial resolution relatively routine.Scanning thermal microscopy and thermal analysis using proximal probes has achieved spatial resolution of 10nm,temperature precision of 50mK,sensitivity to heat ﬂows of 10pW,and the capability for thermal analysis of sub-femtogram samples.VC 2014Author(s).All article content,except where otherwise noted,is licensed under a Creative Commons Attribution 3.0Unported License.[/10.1063/1.4832615]TABLE OF CONTENTSI.INTRODUCTION ............................2II.THERMAL CONDUCTANCE OFINTERFACES...............................3A.Vibrational thermal energy transport atinterfaces (3)1.Overview............................32.Interfacial thermal transport viamolecular dynamics techniques.........33.Role of interfacial bonding and structure.44.Interfaces in composite materials and nanoparticle suspensions...............5a)Electronic mail:d-cahill@0021-8979/2014/1(1)/011305/45VC Author(s)20141,011305-1APPLIED PHYSICS REVIEWS 1,011305(2014)5.Heated nanoparticles (6)6.Experiment (6)B.Near-field radiation transport across a gap..81.Overview (8)2.Experiment (8)3.Theoretical formalism (10)4.Exact treatment of near-field thermaltransfer in non-planar geometries (11)5.Active modulation and control of nearfield thermal transfer (12)6.Image charge theory (12)III.THERMAL TRANSPORT IN NANOSCALE STRUCTURES AND DEVICES (12)A.Physics of phonon transport (12)B.Nanowires and graphene:Experiment andtheory (17)1.Particle transport description of phonon-boundary scattering (17)2.Wave interference models of phonontransport in silicon nanostructures (19)3.Phonon scattering in graphene andnanotubes (20)C.Applications to information technologyand high-power density electronics (21)1.Data storage (21)2.Nanoscale CMOS and interconnects (23)posite substrates for powerelectronics (26)IV.THERMAL CONDUCTIVITY OFNANOSTRUCTURED MATERIALS (27)A.Doping and point defects (28)B.Grain boundaries (28)C.Anisotropic crystals and naturalsuperlattices (30)V.METROLOGY AND PROCESSING TOOLS (31)A.Time-domain thermoreflectance (31)1.Advances (31)2.Limitations (31)3.Implementation (32)4.Signal analysis and sensitivities (32)5.Forefront issues (34)B.Scanning thermal microscopy (34)C.Nanometer-scale thermal analysis andthermal nano-manufacturing (35)VI.OUTLOOK (36)I.INTRODUCTIONThe relentless decrease in the size of devices and struc-tures,the increase in their operating speeds and frequencies, and the ever more aggressive thermal conditions imposed upon them requires sophisticated understanding and control of thermal transport at the nanoscale.While thermal per-formance itself is a key metric for applications such as ther-mal barrier coatings,nuclear fuels,and materials for thermoelectric energy conversion,there are many other tech-nologies for which the ability to manipulate heat is vital even though the primary goal of the structure is non-thermal. Some examples of technology drivers for the science of nanoscale thermal transport are phase change memory devi-ces,heat assisted magnetic recording,thermal management of wide variety of high power and nanoscale electronic and optoelectronic devices,and the proposed use of intensely heated nanoparticles in medical therapies.The objective of this review is to provide perspectives on new developments in the applied physics of nanoscale thermal transport that have resulted from advances in experiment,theory,and simulation over the past decade;to identify gaps in current state-of-knowledge;and discuss directions for future research.This review is an update to an earlier review,1co-authored by some of the same authors,which surveyed progress in theﬁeld through2002. The topics we have selected emphasize the importance of interfacial phenomena in nanoscale thermal transport and avoid topics that have been extensively reviewed by others in recent years, e.g.,nanostructured thermoelectric materials2–7and the transport properties of isolated gra-phene and carbon nanotubes.8–10We limit our discussion of thermoelectric materials to the lattice thermal conductivity of Si nanowires.Our discussion of carbon allotropes focuses on the effects of interfaces on thermal transport. We also omit discussion of non-linear effects and transport in low-dimensional systems as these topics were recently reviewed by Li and co-workers.11Experimental methods for measuring the transport properties of nanowires were recently reviewed by Weathers and Shi.12Thorough devel-opment of the fundamentals of nanoscale thermal transport are available in recent textbooks.13–16For the purposes of this review,the term nanoscale is interpreted liberally,embracing characteristic dimensions ranging from the atomic up to sub-micron.Another way of envisaging the deﬁnition of nanoscale is the regime in which sub-continuum effects are important;that is,the system can-not be adequately described by bulk transport properties and continuum heat transport equations that do not explicitly consider interfaces.For example,while it has long been rec-ognized that grain boundaries and interphase boundaries pro-vide signiﬁcant thermal resistance,there continues to be signiﬁcant efforts to understand the transport of thermal energy across interfaces.One of the major advances in the past decade has been the extension of experiment and theory to interfaces that involve molecular materials and liquids. Systematic control of the strength of interface bonding has revealed the importance of interface chemistry and physics on heat conduction.We include discussion of radiative transport by ther-mally excited electromagnetic modes in this review because we believe that there is an increasing intersection between the science of near-ﬁeld radiative transport through nano-scale gaps and the thermal conductance of interfaces G between materials when G is small because of weak bonding, interface roughness,or a large mismatch in vibrational den-sity of states.The coupling of electronic and vibrational modes at an interface is usually thought to be limited to atomic scales but recent theory suggests that longer-range coupling across the interface can be signiﬁcant.Heterostructures provide both an approach to reducing thermal conductivity in the cross-plane direction and a labo-ratory for studies of highly anisotropic thermal transport. Anisotropy in engineered superlattices has now been extended to natural superlattice materials,such as those in layered perovskite structures.Anisotropy is most extreme in two-dimensional or near two-dimensional materials,of which carbon-based materials(nanotubes,and most recently graphene)are the most prominent;however,considerable work is now being performed on layered metal chalcogenide systems,such as MoS2and WSe2.Historically,theory and simulation have been able to provide predictions with spatial and time resolutions for which corresponding experimental techniques did not exist or were not fully developed.In the last decade,there have been signiﬁcant improvements in the spatial and temporal re-solution of key techniques,and a much improved ability to determine temperatures and heatﬂow.This is now allowing theory and experiment to be confronted with experimental results at an unprecedented level.Advances in density func-tional theory and high performance computing have reached the point where parameter-free predictions of the thermal conductivities of simple crystals are now possible.We begin our discussion with a review of theory and experiment on the transport of heat at an interface between two materials.In Sec.III,we focus on thermal transport in nanostructures and nanoscale electronic devices.The related topic of low thermal conductivity in nanostructured materi-als,including anisotropic crystals and natural superlattices, is addressed in Sec.IV.We explore issues associated with thermal measurement science and thermal processing at the nanoscale in Sec.V.II.THERMAL CONDUCTANCE OF INTERFACESA.Vibrational thermal energy transport at interfaces1.OverviewA thermal boundary resistance is found for the heatﬂow between two materials in contact along a planar interface. The heatﬂow is perpendicular to the planar interfaceJ Q¼G D T;(1) where D T is the small temperature difference between the two sides of the interface,and G is the boundary conduct-ance;G has the units of power per area per degree.A common interface in thermal transport is between two insulators.Then,the heat is carried only by phonons.The thermal boundary resistance GÀ1from phonons wasﬁrst cal-culated by Khalatnikov.17,18He considered only longitudinal phonons.His calculation is called the acoustic mismatch theory(AMT).It is found to be a good approximation at low temperatures,where G/T3.At room temperatures,it is a poor approximation.Young and Maris19provided theﬁrst theory of G,which included all phonons on both sides of the junction.They derived only the special case that both sides of the interface had face-centered-cubic structures,with the same lattice constant.Pettersson and Mahan20extended the Young-Maris theory to include any kind of lattices on the two sides of the interface,but assumed they were in intimate contact.These theories are based on phonon scattering from the interface atoms.Persson and Ueba21recently derived the phonon-phonon case using surface Green’s functions.That allowed them to consider rough surfaces.Superlattices are periodic arrays of alternating materi-als.One layer in the array will have n-atomic layers of a material,while the alternating layers have m atomic layers. Thermal conductivity can be measured parallel to the layers, or perpendicular to them.For a crystalline superlattice,the thermal conductivity parallel to the layers is typically com-parable to the average of the two bulk materials,as long as the interfaces between the layers do not have a large density of defects.The interesting measurement is for heatﬂow per-pendicular to the layers,which is called the“cross-plane direction.”Hyldgaard and Mahan22originally predicted that the thermal conductivity of a superlattice in the cross-plane direction could be ten times smaller than the values of the bulk materials that makeup the superlattice.This reduction is generally observed.The thermal conductivity is some-times lower in value than a random alloy of the same mate-rial.The large reduction in heatﬂow is due to the numerous interfaces of the superlattice.The thermal boundary resist-ance is a major component of the thermal ter Simkin and Mahan23suggested that a superlattice would have a minimum thermal conductivity as a function of the number of atomic layers within one superlattice layer. Several experiments have tested these ideas.24–28(A sum-mary of experimental studies of superlattices prior to2002 is given in Ref.1.)Until recently all theory and experiments on superlatti-ces were for insulating layers.In this case only phonons carry heat,and the boundary resistance is due to phonon scattering.Recently,there has been experimental work on metal-metal interfaces29and multilayers,30where the elec-trons are the important carriers of heat.Some work has been done also on metal-insulator superlattices.27,312.Interfacial thermal transport via molecular dynamics techniquesModeling and simulation of interfacial heat transport has been the focus of numerous computational efforts in the past decade.The most prominent approach is to use molecu-lar dynamics(MD)simulations where atoms and molecules follow classical dynamics based on the numerical solution of the Newton’s second law of motion.The forces between atoms and molecules are derived from interatomic poten-tials.32In the most popular scheme,equal power,P,heat source,and sink are introduced on both sides of the interface, and when the steady state is established,the interfacial ther-mal conductance,G,is evaluated from the temperature drop at the interface,D T,via G¼P=ðA D TÞ,where A is the inter-facial area.While the heat source-sink method allows deter-mination of the value of the conductance,detailed understanding of the thermal coupling across the interface can be obtained from the equilibrium MD simulations.33,34 Speciﬁcally,a Green-Kubo relationship is employed,whichrelates theﬂuctuating cross interfacial heat power,P(t),to the interfacial conductance via35G¼1Ak B Tð1h PðtÞPð0Þi d t;(2)where h PðtÞPð0Þi is the interfacial heat power autocorrela-tion function.The interfacial heat power can be easily obtained by monitoring the total energy of the material on the one side of the interface,and then taking its time deriva-tive.Also,the upper limit of the integral given by Eq.(2)is in practiceﬁnite as the autocorrelation function decays to zero.In addition to the value of G,the full functional form of h PðtÞPð0Þi provides dynamical information about coupling between molecular vibrations in the two phases forming the interface.36Equilibrium and non-equilibrium MD thermal conductiv-ity techniques characterize either macroscopic or interfacial behavior“integrated”over all vibrations.To explicitly pro-vide information on underlying mechanism of heatﬂow in terms of individual vibrations,recently developed phonon dy-namics MD based techniques have proved to be useful.The basic idea of phonon dynamics simulations37is to generate wave packets of lattice vibrations of a narrow range of fre-quencies and well-deﬁned polarization,using the normal modes of the perfect crystal structure,and then to allow them to propagate through the system.Following the scattering pro-cess,one can decompose the transmitted and reﬂected energy into phonons and thus can identify the nature of the scattering processes and to calculate the transmission coefﬁcient for each phonon.38For example,scattering of high frequency phonons at interfaces involves a mixture of“acoustic scat-tering”where the reﬂected phonon has the same character as the incident phonon and“diffusive scattering”where the cor-relation with the incident phonon wave packet is lost.38 The phonon dynamics technique relates to Green’s func-tions methods.39Both methods enable calculations of the phonon transmission coefﬁcients.However,due to computa-tional limitations and difﬁculties with the correct description of anharmonic effects,Green’s functions calculations were mostly performed on simpliﬁed interfacial models,such as junctions,40or nanowires.41The transmission coefﬁcients for longitudinal acoustic phonons determined by phonon dynam-ics simulations are similar to those obtained from GF calcu-lations for a simple one dimensional chain model of masses connected by springs.37,42Green’s function calculations on fully3-dimensional structures,on the other hand,lump to-gether all phonons at a given frequency,whereas phonon dy-namics simulations can discriminate among different directions and polarizations.3.Role of interfacial bonding and structureThe acoustic mismatch model(AMM)and diffusive mismatch model(DMM)have traditionally provided a basis for understanding interfacial thermal resistance.These mod-els provide prescriptions for calculating the transmission coefﬁcient of a phonon with which the interfacial conduct-ance can be obtained by appropriate summations over all phonons.19,43While both AMM and DMM provide values for transmission coefﬁcients,they calculate them purely based on the bulk properties of the two solids forming the interface;thus they do not account explicitly for the strength of the interfacial bonding.Consequently,MD simulations were used to model the effect of interfacial bonding on the interfacial conductance.In particular,a study of a self-assembled monolayer(SAM)water interface(Fig.1) exposed the relationship between interfacial bonding and interfacial conductance,suggesting a more or less linear rela-tionship between the two and saturation on the conductance at high interfacial bonding.44Interestingly,in this case,the MD results are in quantitative agreement with the experi-ment.45A similar relationship between the interfacial con-ductance and the interfacial bonding strength was observed in a number of MD simulation on interfacial systems,includ-ing hard solid-polymer,42solid-solid,46solid-SAM-solid,47,48 carbon nanotube on silica substrate,49and for gas-solid interfaces.50Within the theoretical treatment,the effect of interfacial bonding on the phonon transmission coefﬁcients and conse-quently on the interfacial thermal conductance can be dem-onstrated via an analysis of a simple model of semi-inﬁnite one-dimensional chains of masses connected by springs.51A calculation based on this model shows that the interfacial phonon transmission coefﬁcient for a typical phonon repre-senting those carrying the majority of the heat strongly increases with increasing interfacial stiffness.46Furthermore, the transmission coefﬁcient saturates at strong bonding at the value coinciding which by the prediction of the AMM.A similar conclusion was reached in the case of a fully3 dimensional model,which developed an analytical extension of the AMM that includes the effects of weak interface bond spring constants.52Analysis of the one dimensional chain junctions and of the extended AMM model shows that in the limit of very weak interfacial bonding the conductanceis FIG.1.The interfacial thermal conductance of a range of SAM-water surfa-ces as a function of[1þcosðhÞ],which measures interfacial adhesion strength,where h is the wetting angle.The experimental data are for interfa-ces between water and surfactant coated surfaces,see Ref.45.Reproduced with permission from Phys.Rev.Lett.102,156101(2009).Copyright2009 American Physical Society.proportional to the square of the bonding strength.However, this scaling has little relevance to real interfaces as it holds only for unrealistically weak bonding.At larger interfacial bonding strength corresponding to van der Waals bonding, the relationship between bonding and the conductance is more-or-less linear,and at even larger bonding strength the conductance saturates.This is also consistent with observa-tions made for3dimensional lattice models.19All of the aboveﬁndings suggest that AMM can be,at least empiri-cally,extended to account explicitly for the strength of the interfacial interactions.The above considerations indicate that when the diffuse phonon scattering is not important,the AMM model predic-tion is an upper limit of the possible conductance associated with strong interfacial bonding.When the diffuse scattering is dominant,the DMM predicts that the interfacial transport is maximized when the vibrational spectra on both sites of the interface are closely matching.This motivated MD simu-lations to explore the potential of enhancing and tuning inter-facial thermal transport beyond the limits set by the inherent mismatch between bulk properties the two materials forming the interface.53In particular,it was demonstrated that an interface between vibrationally mismatched solids can be enhanced by the insertion of an interfacialﬁlm with media-ting vibrational properties,or by intermixing of the two solid at the interfacial region.54Another example of such a media-ting layer is an organic SAM used in the bonding of solids, or solids and liquids.In particular,MD simulations demon-strated that a conﬁned water layer between quartz solids could lead to very good thermal transport properties.55 Possible effects of surface nano-patterning56,57on thermal transport were also explored,generally indicating beneﬁts for thermal conduction due to increased surface area and bet-ter vibrational matching at the interface.4.Interfaces in composite materials and nanoparticle suspensionsInterfaces generally present a resistance to heatﬂow in addition to the resistance of bulk materials forming the inter-face.This,due to high density of interfaces,can be particu-larly limiting to heatﬂow in nanocomposite materials.This effect manifests itself most spectacularly in the case of car-bon nanotube(CNT)and graphene composites.Despite the fact that the reported value of thermal conductivity of CNTs and graphene is2000to6000W mÀ1KÀ1along axial and in-plane direction,58,59while most of the polymers have ther-mal conductivity of less than0.5W mÀ1KÀ1,an addition of nanocarbonﬁllers leads to rather limited thermal conductiv-ity enhancements.MD simulations combined with transient laser heating measurement indicated that the interfacial con-ductance is very low,of the order of20MW mÀ2KÀ1.60,61 The associated resistance is equivalent to the resistance of ten of nanometers the matrix materials.Analysis of the MD results shows that such high resistance is due to weak bond-ing between carbon nanoﬁller and the matrix and very strong bonding within the nanocarbonﬁller.In the context of the composite thermal transport,MD simulation exposed differences in value of the interfacial thermal conductance,depending on the mode of the heat transfer across the interface.In particular,it was found that the graphene-organic matrix cross-plane interfacial thermal resistance determined via thermal relaxation method is about 20MW mÀ2KÀ1(Ref.62)and consistent with experimental laser based pump-probe measurements on CNTs water.60 Such consistency lies in the fact that the relaxation method mimics pump-probe measurements.In fact,in both experi-ment and standard MD simulations,the energy is pump pre-dominantly to high frequency modes.As demonstrated by simulations,before dissipating to the matrix,ﬁrst the energy ﬂows from high to low frequency modes within graphene. Consequently,the interfacial thermal resistance in such ther-mal relaxation can be understood in terms of a sum of inter-nal to the graphene resistance and the“external”resistance associated with the heatﬂow across the interface.In the heat source-sink simulations where the heat is added and removed in the matrix away from the interface the interfacial conductance for the heatﬂow perpendicular to the graphene matrix interface was determined to be about 170MW mÀ2KÀ1,62i.e.,almost order of magnitude higher than that obtained from the relaxation simulations.This high conductance can be related to the“external”resistance alone, and heat canﬂow from the matrix via graphene to the matrix on the other side without employing high frequency modes in graphene.Yet another value of the effective interfacial thermal conductance of about30MW mÀ2KÀ1was calculated for the case of heat entering a high-aspect ratio carbon nanoﬁber in order to propagate along theﬁber.63In these cases,the heat enters theﬁber predominantly via low frequency modes involving vibrations normal to the interface.However,rapid transport along the carbonﬁber is facilitated by acoustic modes with no or little normal the interface displacement. Consequently the heatﬂow in this conﬁguration involves energy redistribution over modes within theﬁber and is thus affected by associated internal to theﬁber thermal resistance.All the cases described above show that interfacial ther-mal transport can involve a complicated process in which the phonons carrying most of the heat across the interface are not necessarily the phonons carrying the heat in the bulk or along theﬁber,which in turn makes phonon-phonon cou-pling within each material forming the interface an important factor.In the context of thermal transport in nanoﬂuids(colloi-dal suspensions of solid nanoparticles in heat transferﬂuids), it was postulated that at the interface an ordered liquid layer might have higher thermal conductivity than bulk liquid.64 Molecular dynamics simulation on simple liquids concluded that such an interfacial layer does not contribute signiﬁcantly to heat transfer.65For strong solid-liquid interactions,typical of those in nanoﬂuids with metallic nanoparticles,a percolat-ing network of amorphous-likeﬂuid structures can emerge. This can facilitate additional thermal conduction paths.66 However,a discernible increase in thermal conductivity is possible only for exceedingly small colloidal particles,lim-ited to a few tens of atoms.Furthermore,interpretation of the cooling rates of Au nanoparticles suspended in water and or-ganic solvents does not appear to require any unusual。

(12)DNA damage and repair(2)

(2) Base excision repair (3) Nucleotide excision repair (4) Mismatch repair (5) Double-strand break repair: Non-homologous end joining &
homologous reconbination
Direct DNA damage reversal
Thymine dimers can be directly converted to unlinked thymines by three means: •exposure to low wavelength UV radiation; •photosensitization by tryptophan or tryptophan containing peptides; •Enzymatically: the photolyase enzyme cleaves cyclobutane bridge and has an antenna and a catalytic chromophore and has a wavelength optimum of 385 nm.
Nucleotide excision in mamalian
Bacterial Mammalian
uvrA
RPA, TFIIH
uvrB
XPA (damage recognition) + XPG (cleavage)
uvrC
XPF + ERCC1
uvrD
TFIIH
•Xeroderma pigmentosum (XP) is a heritable disease characterized by an extreme sensitivity of skin to UV radiation. Cells of XP patients and extracts of those cells are deficient in repair of DNA damage.

天线的阻抗、带宽和Q值

1298IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 53, NO. 4, APRIL 2005Impedance, Bandwidth, and Q of AntennasArthur D. Yaghjian, Fellow, IEEE, and Steven R. Best, Senior Member, IEEEAbstract—To address the need for fundamental universally valid deﬁnitions of exact bandwidth and quality factor ( ) of tuned antennas, as well as the need for efﬁcient accurate approximate formulas for computing this bandwidth and , exact and approximate expressions are found for the bandwidth and of a general single-feed (one-port) lossy or lossless linear antenna tuned to resonance or antiresonance. The approximate expression derived for the exact bandwidth of a tuned antenna differs from previous approximate expressions in that it is inversely proportional to the magnitude 0 ( 0 ) of the frequency derivative of the input impedance and, for not too large a bandwidth, it is nearly equal to the exact bandwidth of the tuned antenna at every frequency 0 , that is, throughout antiresonant as well as resonant frequency of bands. It is also shown that an appropriately deﬁned exact a tuned lossy or lossless antenna is approximately proportional to 0 ( 0 ) and thus this is approximately inversely proportional to the bandwidth (for not too large a bandwidth) of a simply tuned antenna at all frequencies. The exact of a tuned antenna is deﬁned in terms of average internal energies that emerge naturally from Maxwell’s equations applied to the tuned antenna. These internal energies, which are similar but not identical to previously deﬁned quality-factor energies, and the associated are proven to increase without bound as the size of an antenna is decreased. Numerical solutions to thin straight-wire and wire-loop lossy and lossless antennas, as well as to a Yagi antenna and a straight-wire antenna embedded in a lossy dispersive dielectric, conﬁrm the accuracy of the approximate expressions and the inverse relationship between the deﬁned bandwidth and the deﬁned over frequency ranges that cover several resonant and antiresonant frequency bands. Index Terms—Antennas, antiresonance, bandwidth, impedance, quality factor, resonance.I. INTRODUCTIONTHE primary purpose of this paper is twofold: ﬁrst, to deﬁne a fundamental, universally applicable measure of bandwidth of a tuned antenna and to derive a useful approximate expression for this bandwidth in terms of the antenna’s input impedance that holds at every frequency, that is, throughout the entire antiresonant as well as resonant frequency ranges of the antenna; and second, to deﬁne an exact antenna quality factor independently of bandwidth, to derive an approximate expression for this exact , and to show that this is approximately inversely proportional to the deﬁned bandwidth. The average “internal” electric, magnetic, and magnetoelectric energies that we use to deﬁne the exact of a linear antenna are similar though not identical to those of previous authors [1]–[8]. The approximate expression for the bandwidthManuscript received October 2, 2003; revised September 14, 2004. This work was supported by the U.S. Air Force Ofﬁce of Scientiﬁc Research (AFOSR). The authors are with the Air Force Research Laboratory, Hanscom AFB, MA 01731 USA (e-mail: arthur.yaghjian@). Digital Object Identiﬁer 10.1109/TAP.2005.844443and its relationship to are both more generally applicable and more accurate than previous formulas. As part of the derivation of the relationship between bandwidth and , exact expressions for the input impedance of the antenna and its derivative with respect to frequency are found in terms of the ﬁelds of the antenna. The exact of a general lossy or lossless antenna is also re-expressed in terms of two dispersion energies and the frequency derivative of the input reactance of the antenna. The value of the total internal energy, as well as one of these dispersion energies, for an antenna with an asymmetric far-ﬁeld magnitude pattern, and thus the value of for such an antenna, is shown to depend on the chosen position of the origin of the coordinate system to which the ﬁelds of the antenna are referenced. A practical method is found to emerge naturally from the derivations that removes this ambiguity from the deﬁnition of for a general antenna.1 The validity and accuracy of the expressions are conﬁrmed by the numerical solutions to straight-wire and wire-loop, lossy and lossless tuned antennas, as well as to a Yagi antenna and a straight-wire antenna embedded in a frequency dependent dielectric material, over a wide enough range of frequencies to cover several resonant and antiresonant frequency bands. The remainder of the paper, many of the results of which were ﬁrst presented in [9], is organized as follows. Preliminary deﬁnitions required for the derivations of the expressions for impedance, bandwidth, and of an antenna are given in Section II. In Section III, the fractional conductance bandwidth and the fractional matched voltage-standing-wave-ratio (VSWR) bandwidth are deﬁned and determined approximately for a general tuned antenna in terms of the input resistance and magnitude of the frequency derivative of the input impedance of the antenna. It is shown that the matched VSWR bandwidth is the more fundamental measure of bandwidth because, unlike the conductance bandwidth, it exists in general for all frequencies at which an antenna is tuned. (Throughout this paper, we are considering only the bandwidth relative to a change in the accepted power and not to any additional loss of bandwidth caused, for example, by a degradation of the far-ﬁeld pattern of the antenna.) In Section IV, the input impedance, its frequency derivative, the internal energies, and the of a tuned antenna are given in terms of the antenna ﬁelds, and the relationship between bandwidth and is determined. In particular, the frequency derivative of the input reactance is expressed in terms of integrals of the electric and magnetic ﬁelds of the tuned antenna. These integrals of the ﬁelds are then re-expressed in terms of internal1This ambiguity in the values of internal energy and engendered by subtracting the radiation-ﬁeld energy of an antenna with an asymmetric far-ﬁeld magnitude pattern is not mentioned or addressed in [1]–[8], probably because these references concentrate on deﬁning the of individual spherical multipoles which have far-ﬁeld magnitude patterns that are symmetric about the origin.QQ0018-926X/$20.00 © 2005 IEEEYAGHJIAN AND BEST: IMPEDANCE, BANDWIDTH, ANDOF ANTENNAS1299energies used to deﬁne the of the antenna and two dispersion energies: the ﬁrst dispersion energy determined by an integral involving the far ﬁeld and the frequency derivative of the far ﬁeld of the antenna; and the second determined by an integral involving the ﬁelds and the frequency derivative of the ﬁelds within the antenna material. The dependence in the value of the far-ﬁeld dispersion energy on the origin of the coordinate system, and thus the ambiguity in (mentioned above), is removed by the procedure derived in Section IV-E. An apparently new energy theorem proven in Appendix B is used to derive a number of inequalities that the constitutive parameters must satisfy in lossless antenna material. We ﬁnd that the Foster reactance theorem, which states that the frequency derivative of the reactance of a one-port linear, lossless, passive network is always positive, does not hold for antennas (whether or not the antenna is lossless because the radiation from the antenna acts as a loss) [10, Sec. 8-4]. Although the general formula we derive for the bandwidth of an antenna involves the frequency derivative of resistance as well as the frequency derivative of reactance, it is found that the half-power matched VSWR bandwidth of a simply tuned lossy or lossless antenna is approximately equal to for all frequencies if the bandwidth of the antenna is not too large. It is proven in Appendix C that the of an antenna increases extremely rapidly as the maximum dimension of the source region is decreased while maintaining the frequency, efﬁciency, and far-ﬁeld pattern—making supergain above a few dB impractical. It is also shown in Appendix C that the quality factors determined by previous authors [1]–[3] are lower bounds applied to electrically small antennas with for our deﬁned and . nondispersive In Section V, we discuss how the internal energy, , and bandwidth of an antenna would be affected by the presence of mateor . rial with negative values of In Section VI, exact VSWR bandwidths are computed from the magnitude of the reﬂection coefﬁcient versus frequency curves obtained from the numerical solutions to tuned, thin straight-wire and wire-loop lossy and lossless antennas ranging in length from a small fraction of a wavelength to many wavelengths, as well as to a tuned Yagi antenna and a straight-wire antenna embedded in a frequency dependent dielectric material. for these antennas are computed from The exact values of the general expression (80) derived for the of tuned antennas. The exact values of VSWR bandwidth and are compared to the approximate values obtained from the derived approximate formulas in (87) for VSWR bandwidth and . These numerical comparisons conﬁrm that the approximate formulas in (87) of a tuned antenna give much for VSWR bandwidth and more accurate values in antiresonant frequency ranges than the conventional formula (81) (or its absolute value) commonly used to determine bandwidth and quality factor. Before leaving this Introduction, a few remarks about the usefulness of antenna may be appropriate. We can ask why the concept of antenna is introduced when it is the bandwidth of an antenna that has practical importance. One advantage of is that the inverse of the matched VSWR bandwidth of an anis approximated by the value of tenna tuned at the frequency the of the antenna at the single frequency . The bandwidth of some antennas may be much more difﬁcult to directly com-Fig. 1. Schematic of a general transmitting antenna, its feed line, and its shielded power supply.pute, measure, or estimate than the , which is fundamentally deﬁned in terms of the ﬁelds of the antenna, is independent of the characteristic impedance of the antenna’s feed line, and has a number of lower-bound formulas derived in the published literature [1]–[3] (see Appendix C). The simple approximate, yet accurate formulas for exact bandwidth and that are derived in the present paper can be evaluated for an antenna and compared to the lower bounds for to decide if the antenna is nearly optimized with respect to and bandwidth. It is often possible to increase the bandwidth of electrically small antennas by simply restructuring the antenna to reduce its interior ﬁelds and therefore its [11]. Moreover, because the of an antenna is determined by the ﬁelds of the antenna, Maxwell’s equations can be used, as we do in Appendix C, to obtain fundamental limitations on the bandwidth of antennas. Finally, regardless of the utility of the concepts of and bandwidth, it seems quite remarkable that at any frequency of most antennas, the , which is deﬁned in terms of the ﬁelds of a simply tuned one-port linear passive antenna, and the bandwidth, which is deﬁned in terms of the input reﬂection coefﬁcient of the same antenna, are approximately inversely proportional (provided the bandwidth is narrow enough) and that this approximate inverse relationship is given by the simple formulas in (87) below. II. PRELIMINARY DEFINITIONS Consider a general transmitting antenna (shown schematically in Fig. 1) composed of electromagnetically linear materials and fed by a waveguide or transmission line (hereinafter referred to as the “feed line”) that carries just one propagating frequency . (The feed mode at the time-harmonic line is assumed to be composed of perfect conductors separated by a linear, homogeneous, isotropic medium.) The propagating mode in the feed line can be characterized at a reference plane (which separates the antenna from its shielded power supply) , complex current , and complex by a complex voltage deﬁned as input impedance (1) is the input resistance and the real where the real number is the input reactance of the antenna. The voltage number and current can also be decomposed into complex coefﬁcients and of the propagating mode traveling toward (incident) and away (emergent) from the antenna, respectively, such that (2)1300IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 53, NO. 4, APRIL 2005(12) Because the tuning inductor or capacitor is assumed lossless and in series with the antenna, . The frequency , at , deﬁnes a resonant frequency of the antenna which and an antiresonant frequency of the antenna if if .2 For the sake of brevity, we shall sometimes as simply the refer to the resonant or antiresonant frequency “tuned frequency”. Note that we are deﬁning a “tuned antenna” at the frequency as an antenna that has a total input reactance equal to zero at . Therefore, a tuned antenna will not have equal to zero unless the chara reﬂection coefﬁcient acteristic impedance of its feed line is matched to the antenna at the frequency . If an untuned antenna has , it is said to have a natural resonant frequency at if and a natural antiresonant frequency at if . The tangential electric and magnetic ﬁelds on of the feed line can be written in terms the reference plane of the of real electric and magnetic basis ﬁelds and cursingle propagating feed-line mode with voltage rent ; speciﬁcally (13) There may be evanescent modes on the feed line, but the ﬁelds of these evanescent modes are assumed to be negligible on the reference plane . If the dimensional units of and are chosen as (meter) and they are consistent with Maxwell’s equations in the International System of mksA units, then has units of Volts, has units of Amperes, and the characof the feed line can be chosen as a real teristic impedance positive constant independent of frequency with units of Ohms. It then follows that the normalization of the basis ﬁelds may be expressed as a nondimensional number equal to one, that is (14)Fig. 2. Schematic of a general transmitting antenna, its feed line, its shielded power supply, and a series reactance X .with equal to the feed-line characteristic impedance, which can be chosen to be independent of frequency [12, pp. 255–256]. Alternatively, and can be deﬁned in terms of and as(3) The reﬂection coefﬁcient of the antenna is deﬁned as (4) As indicated, the parameters , and , as well as , and , are in general functions of . with a series Assume the antenna is tuned at a frequency (as shown in Fig. 2) comprised of either a posreactance or a positive series capacitance , itive series inductance where and are independent of frequency, to make the total reactance(5) equal to zero at , that is (6) Then the derivative of as with respect to can be written(7) or simply as (8) at the frequency . The equations corresponding to (1)–(4) for the tuned antenna can be written as(9) (10) (11)is the unit normal (pointing toward the antenna) on where simply cuts two wire leads from the plane . If the plane and refer to cona generator at quasistatic frequencies, ventional circuit voltages and currents that do not serve as genuine modal coefﬁcients. In that case, the equations in (11) beequal to the internal recome deﬁnitions of and with sistance of the generator whose internal reactance is tuned to zero. For the TEM mode on a coaxial cable, the basis ﬁelds , as well as the characteristic impedance , are independent of frequency. Also, one of the basis ﬁelds, either or , in addition to , can always be made independent of frequency for feed lines composed of perfect conductors separated by linear, homogeneous, isotropic materials [12, pp. 255–256]. We shall use this fact in deriving (64) below.2These deﬁnitions of resonance and antiresonance come from the behavior of the reactance of series and parallel RLC circuits, respectively, at their natural frequencies of oscillation. At the “resonant frequency” of a series RLC circuit with positive L and C; X > 0 and at the “antiresonant frequency” of a parallel RLC circuit with positive L and C; X < 0.YAGHJIAN AND BEST: IMPEDANCE, BANDWIDTH, ANDOF ANTENNAS1301With the help of (14) we can determine various expressions accepted by the antenna for the total powerdeﬁnes what is commonly called the matched VSWR bandwidth. We shall show that the matched VSWR bandwidth, unlike the conductance bandwidth, is well-deﬁned for all frequencies at which the antenna is tuned to zero reactance. A. Conductance Bandwidth(15) or(16) in (15) denotes the complex conjugate and in (16) is the input conductance of the antenna. The power accepted by the antenna equals the power dissipated by the antenna in the form of power radiated by the antenna plus the power loss in the material of the of the antenna antenna. Deﬁning the radiation resistance and the loss resistance of the antenna as as , we have The superscriptThe conductance bandwidth for an antenna tuned at a freis deﬁned as the difference between the two frequenquency cies at which the power accepted by the antenna, excited by a constant value of voltage , is a given fraction of the power accepted at the frequency . With the help of (9), the conductance at a frequency of an antenna tuned at the frequency can be written as (21) We can immediately see from (21) that there is a problem with using conductance bandwidth, namely, that the derivative of evaluated at equals (22) unless . This means that and thus it is not zero at in general the conductance will not reach a maximum at the frequency . Moreover, in antiresonant frequency ranges where both the resistance and reactance of the antenna are changing rapidly with frequency, the conductance may not possess a maximum and consequently the conductance bandwidth may not exist in these antiresonant frequency ranges. (As we shall show in Section III-B, the matched VSWR bandwidth does not suffer from these limitations.) Well away from the antiresonant frequency ranges of most is much smaller than antennas, we have , the conductance will peak at a frequency much closer to than the bandwidth, and a simple approximate expression for the conductance bandwidth can be found as follows. so that , we Having tuned the antenna at where by taking the can ﬁnd the frequency frequency derivative of the expression for in (21) and setting it equal to zero to get(17) so that (18) The power radiated can also be expressed in terms of the far ﬁelds of the antenna(19) where is a surface in free space surrounding the antenna and its power supply, the solid angle integration element equals with being the usual spherical coordinates of the position vector , and the complex is deﬁned by far electric ﬁeld pattern (20) with being the speed of light in free space. The impedance of free space is denoted by in (19) and is the unit normal out of . The radiation resistance is always equal because the power rato or greater than zero diated by the antenna is always equal to or greater than zero . Also, the loss resistance is equal to or greater if the material of the antenna is passive than zero . III. FORMULAS FOR THE BANDWIDTH OF ANTENNAS The bandwidth of an antenna tuned to zero reactance is often deﬁned in one of two ways. The ﬁrst way deﬁnes what is commonly called the conductance bandwidth and the second way(23) , the functions With their derivatives can be expanded in Taylor series about and (24a) (24b) (24c) (24d) which can be substituted into (23) to obtain for small(25) or (26)1302IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 53, NO. 4, APRIL 2005In resonant frequency ranges well away from antiresonant ranges, we can assume so that (26) reduces to (27) in the peak of the conductance That is, the frequency shift of an antenna tuned at the frequency in a resonant freis given by the simple relationship quency range in (27) involving only the input resistance and the ﬁrst frequency derivatives of the input resistance and reactance of the antenna peaks at a at the tuned frequency . In other words, given by frequency (28) To determine the conductance bandwidth about the shifted at which peaks when the antenna is tuned frequency at which at , we ﬁnd the two frequencies the accepted power is times its value at is given from (21) as (29) provided, as discussed above, we are well within the resonant . The value of the frequency ranges where constant , which lies in the range , is assumed . We can re-express (29) as in (30), shown at the chosen bottom of the page, whose left-hand side is more suitable to a than the left-hand side of (29) power series expansion about because the function , which rapidly varies from its value of zero at , is not contained in the denominator of (30). Since the conductance on the left-hand side of (30), and its , a Taylor series expansion ﬁrst derivative, are zero at of the left-hand side of (30) about recasts (30) in the form has been of (31), shown at the bottom of the page, in which because for replaced by well within resonant frequency ranges. Evaluating the second derivative in (31), we ﬁnd. Again, in resonant frewhere use has been made of quency ranges we can assume that and, therefore, (32) yields (33) under the additional assumption that the terms are negligible, an assumption that is generally satisﬁed if . is therefore The fractional conductance bandwidth given approximately by(34) under the assumptions that we are well within resonant frewhere and quency ranges and do not change greatly over the bandwidth or, equivalently, (an assumption that holds if , which can always be satisﬁed if is chosen small enough). The expression (34) for the fractional conductance bandwidth of tuned antennas was derived previously by , assuming Fante [3] for the half-power bandwidth . Rhodes [13] postulates the “half-power bandwidth” of an “electromagnetic system” as (35) as the of the electromagnetic system and He then deﬁnes ﬁnds “stored electric and magnetic energies” that are consistent and (59) below. The shortcomings of this with this method are that (35) is postulated as the half-power bandwidth rather than of a general antenna and that is deﬁned as as a physical quantity determined independently of from the ﬁelds of the antenna. Moreover, (35) as well as (34) does not accurately approximate the bandwidth of tuned antennas in antiresonant frequency ranges (except at antiresonant frequencies ). with B. Matched VSWR Bandwidth (32) The matched voltage-standing-wave-ratio (VSWR) bandwidth for an antenna tuned at a frequency is deﬁned as the(30)(31)YAGHJIAN AND BEST: IMPEDANCE, BANDWIDTH, ANDOF ANTENNAS1303difference between the two frequencies on either side of at which the VSWR equals a constant , or, equivalently, at which the magnitude squared of the reﬂection coefﬁcient equals (the constant is assumed ), provided the characteristic impedance of chosen . Then the magnitude the feed line equals squared of the reﬂection coefﬁcient can be found from (12) as (36) Both and its derivative with respect to are zero at . has a minimum at for all values of Consequently, at which the antenna is tuned the frequency and matched to the feed line . This means that the matched VSWR bandwidth, , determined by (37) unlike the conductance bandwidth, exists at all frequencies (for small enough ), that is, throughout both the antiresonant and resonant frequency ranges. Therefore, the matched VSWR bandwidth is a more fundamental, universally applicable deﬁnition of bandwidth for a general antenna than conductance bandwidth. Bringing the denominator from the left-hand side of (37) to the right-hand side and rearranging terms to remove the rapidly from the denominator on the left-hand varying function side of (37) producesis chosen small enough). For half-power VSWR bandwidth, and . A comparison of (41) with (34) reveals that under their stated conditions of validity (42) exists, wherever the conductance bandwidth namely outside the antiresonant frequency ranges. The matched has the distinct advantage over VSWR bandwidth the conductance bandwidth of existing at every (for small enough ), that is, within both tuned frequency and antiresonant freresonant and do not change quency ranges. Moreover, if greatly over the bandwidth (which can always be satisﬁed if is chosen small enough), is reasonably well approximated at all tuned frequencies by the simple expression or are zero, (41) even in frequency bands where close to zero, or negative (but not both and too close to zero). As far as we know, (41) is a general result for antennas that has not been established previously. The approximate formula for bandwidth in (41) should be applied judiciously to antennas that are designed to have a combination of two or more natural resonances and antiresonances at that are so close together that versus has closely spaced peaks the curve of equal to unity at these frequen, for example, may cies. Then the half-power bandwidth extend over all these natural resonant and antiresonant frequencies even though there will be a resonant peak in at each natural resonant or antiresonant frequency that has (say its own bandwidth for some such that ). The formula in (41) approximates the bandwidth of each of these individual minor resonant and antiresonant peaks with some that is less than . IV. FORMULAS FOR IMPEDANCE AND AND ITS RELATIONSHIP TO BANDWIDTH The formula for matched VSWR bandwidth given in (41) re, the derivative of impedance quires, in addition to , that is, with respect to frequency evaluated at . As we shall see, an explicit expression for in terms of the electromagnetic ﬁelds is not needed in the derivation of and its relationship to the bandwidth of a tuned antenna. On the other hand, the evaluation of the fre, in terms of the elecquency derivative of the reactance, tromagnetic ﬁelds of the antenna is crucial to the derivation of and its relationship to bandwidth. As a lead-in to the desired , we begin by deriving general expresexpression for of an antenna tuned at sions for the input impedance in terms of the ﬁelds of the antenna. A. Field Expressions for Accepted Power and Input Impedance To obtain expressions for the input impedance of the antenna shown in Fig. 2 tuned at the frequency , apply the complex Poynting’s theorem [10, (1-54)] to the inﬁnite volume(38) Expanding the left-hand side of (38) in a Taylor series about we ﬁnd ,(39) under the assumption that the terms are negligible. . The This assumption is generally satisﬁed if are solutions to (39) for (40) so that the fractional matched VSWR bandwidth takes the simple form(41) which holds for tuned antennas under the sufﬁcient condiand do not change greatly over the tions that or, equivbandwidth (conditions that hold if , which can always be satisﬁed if alently,1304IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 53, NO. 4, APRIL 2005outside the volume of the shielded power supply. The includes the volume of the antenna material that volume lies to the right of the feed-line reference plane . The closed surfaces of the volumes and have the feed-line reference in common. Therefore, the volume includes the plane . Assuming the involume of the series tuning reactance tegral of the Poynting’s vector is zero over the shielded surface of the power supply and using (13)–(14), we ﬁndThroughout the derivations in Sections II and III, it is assumed that the antennas are linear, that is, composed of materials governed by linear constitutive relations that relate and to and . With the most general linear, spatially nondispersive constitutive relations (51) where , and are the permeability dyadic, the permittivity dyadic, and the magnetoelectric dyadics, respectively, the reactance in (49) and (50) of the antenna tuned at the frequency can be written as(43) where, as in (17) (44) is given in terms of the ﬁelds by (19) The power radiated and the power loss is given as (45) and (52)(53) in which the subscript “ ” on a dyadic denotes its transpose. All the ﬁeld vectors as well as the real and imaginary parts , and are, in general, functions of both frequency of and the spatial position vector . Outside the volume of the , and in , antenna material, and are the permeability and permittivity of free where space and is the unit dyadic. With the constitutive relations in (51), the power loss and power accepted in (45) and (46) becomein passive material. Then the power accepted, where which equals the total power dissipated by the antenna, can be written as(46) (54) (47) (55) which has a value equal to or less than unity. The usual elecand , tric and magnetic vectors are denoted by , the vector being the currespectively, with rent density. Since , we ﬁnd from (43) that (48) and (49) In lossless material is and the loss matrix is zero, that Since for all values of and in passive material, (54) implies that a material is passive (lossy or lossless) if and only if its associated Hermitian “loss” matrix is positive semideﬁnite [14], [15], [16, Sec. 5.2], a property that can be expressed symbolically as (56)The efﬁciencyof the antenna is deﬁned asOf course, the reactance of the antenna is equal to zero at the , that is tuned frequency (50)(57) If the material is reciprocal, Sec. 5.1]. , and [16,。

无创dna阳性结果的验证分析及临床意义

无创DNA阳性结果的验证分析及临床意义黎洛冰1 梁西岚1 聂俊玮21.广东省茂名市妇幼保健院产前诊断中心，广东茂名 525000；2.广东省茂名市妇幼保健院遗传优生中心，广东茂名 525000[摘要] 目的对比分析无创DNA产前检测阳性结果与产前诊断结果，为无创DNA临床应用提供临床应用依据。

方法选取2016年1月～2018年3月在茂名市产前诊断中心因无创DNA产前检测结果阳性的孕妇86例给予羊水或脐静脉穿刺进行核型分析，并对参与无创DNA产前检测结果阴性的孕妇5008例进行随访。

观察无创DNA检测结果准确率、不同危险分析度孕妇检测结果的准确性。

结果 86无创DNA阳性结果，经染色体核型分析验证，无创DNA检测准确率为66.28%，其中18三体检测准确率为100.00%，21三体检测准确率为82.93%，13三体及性染色体异常的检测准确率分别为66.67%、60%。

高龄组、唐氏高风险组、其它高危因素组孕妇无创DNA阳性准确率分别为62.86%、72.73%、65.52%，三组准确率比较，差异无统计学意义（P＞0.05），其余5008例无创DNA结果阴性者截止2018年3月经随访未发现有唐氏综合征患儿出生，其他先天性畸形7例，其中先天性心脏病3例，多指/趾2例，唇腭裂2例。

所有胎儿均正常出生。

结论无创DNA是产前筛查21、18、13三体综合征的有效方法，对于其它染色体异常也具有重要提示意义。

但无创DNA存在假阳性，对于无创DNA检测结果阳性，建议进一步行介入性产前诊断确诊。

[关键词] 无创DNA；产前诊断；出生缺陷；染色体[中图分类号] R714.15 [文献标识码] A [文章编号] 2095-0616（2020）01-256-05Validation analysis and clinical significance of non-invasive DNA positive resultsLI Luobing1 LIANG Xilan1 NIE Junwei21.Prenatal Diagnosis Center,Maoming Maternal and Child Health Hospital,Maoming 525000,China;2.Hereditary andEugenic Center,Maoming Maternal and Child Health Hospital,Maoming 525000,China[Abstract] Objective To compare and analyze the positive results and prenatal prognostic diagnosis of noninvasive DNA prenatal detection so as to provide the basis for clinical application of noninvasive DNA. Methods A total of 86 pregnant women who were positive for non-invasive DNA prenatal testing at the Prenatal Diagnostic Center in Maoming from January 2016 to March 2018 were given amniocentesis or umbilical vein puncture for karyotype analysis.A total of 5008 pregnant women with negative results of noninvasive DNA prenatal testing were followed up.The accuracy of non-invasive DNA test results and accuracy of test results for pregnant women with different risk analysis were observed. Results The positive results of 86 cases of non-invasive DNA were verified by chromosome karyotype analysis,and the accuracy of non-invasive DNA detection was 66.28%.Among which, the detection accuracy of trisomy 18 was 100.00%,that of trisomy 21 was 82.93%,and that of trisomy 13 and sex chromosome abnormalities was 66.67% and 60%,respectively.The accuracy rates of non-invasive DNA positive results in pregnant women in the elderly group,Down’s high-risk group and Down’s critical risk group were 62.86%,72.73% and 65.52%,respectively.There was no statistically significant difference in the accuracy of the three groups (P＞0.05).In the remaining 5008 patients with negative non-invasive DNA results,no children with Down’s syndrome were born in the follow-up until March 2018.Other congenital malformations were found in 7 cases,including 3 cases of congenital heart disease,2 cases of multiple fingers and toes and 2 cases of cleft lip and palate.All fetuses are born normally.After amniocentesis, the amniotic fluid verification rates of T21,T18,T13,sex chromosome abnormalities and other conditions were respectively84.62%,80.00%,66.67%,50.00% and 71.43% in patients with positive results of non-invasive DNA test. ConclusionNoninvasive DNA is an effective method for prenatal screening of trisomy 21,18 and 13 syndromes,which also has important implications for other chromosomal abnormalities.However,there is a false positive in non-invasive DNA.For non-invasive DNA test results,it is recommended to conduct further interventional prenatal diagnosis.[Key words] Noninvasive DNA;Prenatal diagnosis;Birth defects;Chromosomes预防胎儿出生缺陷，对严重智力障碍及畸形的胎儿尽早检出并及早终止妊娠是提高出生人口质量的重要手段之一[1]。

医学影像学课件：Radiology Skull and Brain-2016

of brain
The slice at 4cm above the base line: - Third ventricle - Quadrigeminal cistern
Normal axial CT of brain
The slice at 5cm above the base line: - Anterior horn of lateral ventricle - Third ventricle - Trigon area of lateral ventricle - Superior cerebellar cistern - Lateral fissure cistern
Head Trauma
Linear fracture - CT shows a sharp, dark
Head MRI
Gray degree of normal tissue on T1, T2WI
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- Matrix 256 x 160 (512Z) - 5 mm / 0 mm - 3:32, 1 nex - 21 FOV, 16 kHz
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TR/TE 4367 / 102, 32 ET

Floral developmental morphology of three Indigofera species

ORIGINAL ARTICLEFloral developmental morphology of three Indigofera species (Leguminosae)and its systematic signiﬁcance within PapilionoideaeJuliana Villela Paulino •Milton Groppo•Simone de Pa´dua Teixeira Received:10May 2010/Accepted:20December 2010ÓSpringer-Verlag 2011Abstract Inﬂorescence and ﬂoral development of three species of Indigofera (Leguminosae-Papilionoideae),I.lespedezioides,I.spicata ,and I.suffruticosa ,were inves-tigated and compared with that of other papilionoid groups,especially with members of the recently circumscribed Millettioid clade,which was merged as sister to Indigofe-reae in a recent cladistic analysis.Although Indigofera is a genus of special interest,because of its great richness in species and its economic importance,few studies have been made of ﬂoral development in the genus or in Indigofereae as a whole.Flower buds and inﬂorescences were analysed at several stages of development in the three species.Our results conﬁrmed that Indigofera species bear a usual inﬂorescence type among legumes,the raceme,which comprises ﬂowers initiated in acropetal succession,each with a subtending bract and no bracteoles initiated.The inception of the ﬂoral organs is as follows:sepals (5),petals (5),carpel (1),outer stamens (5),and,ﬁnally,inner stamens (5).Organ initiation in the sepal,petal,and both stamen whorls is unidirectional,from the abaxial side;the carpel cleft is adaxial.The vexillum is larger than other petals at maturity,covering the keels,which are fused edge-to-edge.Nine ﬁlaments are fused to form an adaxially open sheath,and the adaxial stamen of the inner whorlremains free (diadelphous androecium)in the mid-stage of development.Most of the infra-generic differences occur-red in the later stages of development.Data on ﬂoral development in Indigofera obtained here were also com-pared with those from other members of Papilionoideae.This comparison showed that the early expression of zygomorphy is shared with other members of the Mil-lettioid clade but is rarely found in other papilionoids,corresponding to a hypothetically morphological synapo-morphy in the pair Indigoferae plus millettioids.Keywords Anatomy ÁFlower ÁIndigofera ÁOntogeny ÁSurface analysis ÁSystematicIntroductionThe study of ﬂoral development deals with the ontogenetic stages of the formation of ﬂowers,including their organs,tissues or cells (Foster and Gifford 1974).Among the angiosperms,ﬂoral development has been most extensively studied in the Leguminosae.Besides the great number of genera and species (727genera,more than 19,000species;Lewis et al.2005),the family is interesting because of its diverse ﬂoral symmetry,with actinomorphic to zygomor-phic pattern changes in closely related taxa (Tucker 1997).Different types of inﬂorescences have been reported,and the controversial typology of these inﬂorescences must be re-evaluated in the light of comparative developmental studies (Tucker 1987).Leguminosae have been supported as a monophyleticgroup on the basis of different molecular markers (Ka¨ss and Wink 1996;Doyle et al.2000;Kajita et al.2001;Wojciechowski et al.2004).Some morphological charac-teristics can be pointed out as putative synapomorphiesJ.V.Paulino ÁM.GroppoDepartamento de Biologia,Faculdade de Filosoﬁa Cieˆncias e Letras de Ribeira ˜o Preto,Po ´s-Graduac ¸a˜o em Biologia Comparada,Universidade de Sa˜o Paulo (USP),Av Bandeirantes 3.900,Ribeira˜o Preto,SP 14040-901,Brazil S.de Pa´dua Teixeira (&)Departamento de Cieˆncias Farmace ˆuticas,Faculdade de Cie ˆncias Farmaceˆuticas de Ribeira ˜o Preto,Universidade de Sa ˜o Paulo (USP),Av.do Cafe´s/n 8,Ribeirao Preto,SP 14040-903,Brazil e-mail:spadua@p.brPlant Syst EvolDOI 10.1007/s00606-010-0405-z(Chappill 1995;Doyle et al.2000),with the most evident being the presence of a gynoecium with a single carpel (Dickison 1981;Tucker 2003a ).As traditionally circum-scribed,Leguminosae are divided into three subfamilies:Mimosoideae,Caesalpiniodeae,and Papilionoideae (Lewis et al.2005).Papilionoideae (476genera,13,860species,the richest subfamily)encompasses representatives with zygomorphic,papilionaceous ﬂowers,with an attractive adaxial petal (the vexillum),two lateral petals (the wings),and two petals forming the keel,which encloses the fertile elements of the ﬂowers.Gain or loss of ﬂoral organs is rare but may occur in some groups,as in the tribe Swartzieae.As in the entire family,the gynoecium is formed by a single carpel,but some Swartzia (and some Inga ,Mimo-soideae)are multicarpelate (Tucker 2003a ).The internal relationships within Papilionoideae have been investigated mainly by using cpDNA data from the trn L region (Ireland et al.2000;Pennington et al.2001)and mat K gene (Wojciechowski et al.2004).The study of Wojciechowski et al.(2004)resolved many clades in Papilionoideae and divided the subfamily into ‘‘basal’’groups (for example the Swartzioids)and at least seven major subclades:Cladrastis,genistoid sensu lato,dal-bergioid sensu lato,mirbelioid,millettioid,robinioid,and the inverted-repeat-lacking-clade (IRLC),with the last two being part of the great clade Hologalegina.One of the minor clades in Papilionoideae is formed by the tribe Indigofereae,sister to the millettioid clade and composed of six genera (Lewis et al.2005;Schrire et al.2009).The type genus of the group,Indigofera ,is a worldwide tropical and subtropical taxon with approxi-mately 750species,making it the third-largest genus among Leguminosae (Schrire 2005).The phylogenies of Indigofereae as a whole and of Indigofera speciﬁcally have been studied by Schrire et al.(2003,2009),who,in their 2009paper,presented an extensive cladistic analysis of the tribe and of Indigofera ,considering the monospeciﬁc genus Disynstemon (tribe Millettieae,millettioid clade,endemic to Madagascar)as sister to Indigofereae.The potential systematic signiﬁcance of inﬂorescence and ﬂoral developmental characters within Indigofera or even in the millettioid clade has not yet been explored.Hence,the objective of this study was to ﬁll part of this gap in our knowledge by studying and comparing inﬂorescenceTable 1Morphological characteristics of three species of Indigofera used in this study Species Habitus Inﬂorescence Number of leaﬂets Pod VoucherI.lespedezioides Erect sub-shrubs As long as leaves 1–7Straight M.S.Ogasawara n.n.(SPFR 9926)I.spicata Crawling herbs Much longer than leaves 5–11Straight S.P.Teixeira n.n.(SPFR 7921)I.suffruticosa Ramiﬁed shrubMuch shorter than leaves7–11CurvedS.P.Teixeira n.n.(SPFR 7923)Characteristics of pods according to Moreira and Tozzi (1997).Vouchers at herbarium SPFRn.n.,nonumberFigs.1–18Floral morphology of Indigofera lespedezioides (Figs.1,4,7,10,13,and 16),I.spicata (Figs.2,5,8,11,14,and 17),and I.suffruticosa (Figs.3,6,9,12,15,and 18).Figs.1–3Flower in frontal view.Figs.4–18Floral organs dissected.Figs.4–6Calyx in dorsal view,showing non-secretory trichomes.Figs.7–9Wing in frontal view.Figs.10–12Keels in dorsal view,showing spurs.Figs.13–15Diadelphous androecious.Fig.16Carpel cleft with non-secretory trichomes.Fig.17Carpel with non-secretory trichomes on the lateral side.Fig.18Carpel cleft with non-secretory trichomes.Scale bars Figs.1–18=1mmJ.V.Paulino et al.and ﬂoral development in three species of Indigofera :I.lespedezioides Kunth.,I.spicata Forssk.and I.suffruticosa Mill.Additionally,our ﬁndings were compared with data from other papilionoids and,especially,members of the closer Millettioid Clade,putting our data into a phyloge-netic context.Materials and methodsThis work includes three species found in Brazil that are members of two different subclades that emerged in thestudy of Schrire et al.(2009):Indigofera lespedezioides and I.spicata ,members of the Tethyan clade,and I.suf-fruticosa ,from the Pantropical clade (explanations of the circumscriptions of clades are given by Schrire et al.2009).Species were chosen in an attempt to cover the group’s diversity in terms of habitus and external morphology of inﬂorescences,ﬂowers,pods,and leaves (Table 1).The studies of inﬂorescence and ﬂower development were carried out on ﬂower buds and inﬂorescences of several sizes,which were collected from plants cultivated at FCFRP,USP campus,Ribeira˜o Preto,Sa ˜o Paulo state,Brazil,and from plants of natural populations at UFV,Vic ¸osa,MinasFigs.19–24Inﬂorescence and early ﬂower development of Indigofera lespedezioides (SEM).Fig.19Inﬂorescence with helical acropetal initiation of ﬂoral apices.Fig.20First sepal primordia initiating on abaxial side.Fig.21First two petal primordia initiating on abaxial side.Fig.22Unidirectional order of petal initiation,initiation of ﬁrst antesepalous stamenprimordium and of carpelprimordium.Fig.23Initiation of two antepetalous stamen primordia on abaxial side.Fig.24All organs initiated and the carpel cleft (arrow )is distinguishable.The adaxial side is on the top and the abaxial side of the ﬂower is on the bottom of the images.Symbols:br bract,c carpel,ipinﬂorescence apex,p petal,s sepal,ap antepetalous stamen,as antesepalous stamen.Scale bars Fig.19=100l m;Fig.20,Fig.21=20l m;Figs.22–24=10l mFloral developmental morphology of three Indigofera speciesGerais state,Brazil.The earlier stages of ﬂoral development were observed in buds ranging in length from 0.1to 0.5mm;the mid-stage buds were approximately 1.0mm long,and the late stage buds were approximately 2.0mm long.Vouchers were deposited in the Herbarium of theDepartment of Biology,FFCLRP-USP,Ribeira˜o Preto,USP (Herbarium SPFR;Table 1).Surface analyses of ﬂoral organs were conducted with materials ﬁxed in buffered neutral formalin (BNF;Lillie 1954)or formalin–acetic acid–ethanol (FAA,Johansen 1940)for 24h and stored in 70%alcohol.Subsequently,the material was dissected in absolute alcohol under a stereomicroscope,critical-point dried in a Balzers CPD 030,mounted on aluminium stubs with colloidal carbon,and coated with gold in a Balzers SCD 050sputter coater.Samples (95for I.spicata ,105for I.suffruticosa ,and 50for I.lespedezioides )of at least two individuals per species were observed with Jeol JSM 5200and Zeiss IVO 50scanning electron microscopes.For anatomical analyses,material was ﬁxed in BNF or in Karnovsky’s solution (0.075M in phosphate buffer,pH 7.2–7.4)(Karnovsky 1965)for 24h,dehydrated grad-ually in an ethanol–xylol series and embedded in parafﬁn (Johansen 1940)or historesin (Gerrits 1991).Transverse and longitudinal sections (0.5–6l m thick)were then cut using a Leica RM 2245rotary microtome and a Leica Reichert ultramicrotome.Sections were stained with 0.05%toluidine blue (O’Brien et al.1964)and mountedinFigs.25–28Mid and late-stages of ﬂoral development of Indigofera lespedezioides (SEM).Fig.25Precocious elongation of vexillum.Fig.26Formation of the diadelphous androecium (arrow ).Fig.27Gynoecium with fused cleft (arrow ).Fig.28Trichome arrangement on the carpel and anthers,showing the anther appendix curved to the ventral side.Symbols:ap antepetalous stamen,as antesepalous stamen,c carpel,k keel,v vexillum,w wing.Scale bars Fig.25=30l m;Fig.26,Fig.28=200l m;Fig.27=100l mJ.V.Paulino et al.synthetic resin (Gerlach 1969).Approximately 20samples were examined for each species.Inﬂorescence and ﬂower development were monitored daily in the ﬁeld from two plants of Indigofera lespedezioides (n =3inﬂorescences,45ﬂowers),four plants of I.spicata (n =4inﬂorescences,56ﬂowers),and three plants of I.suffruticosa (n =5inﬂorescences,103ﬂowers).The terminology used to describe ﬂoral development followed Tucker (1987)and Klitgaard (1999).The adaxial side of a ﬂower is the upper side,closest to the inﬂores-cence axis,and the abaxial side is the lower side,opposite to the inﬂorescence axis,closest to the subtending bract (Tucker 1984).To place the ﬁndings of this study in a phylogenetic context within the Papilionoideae,our results were compared with those observed for otherpapilionaceous groups in which data from inﬂorescence and ﬂoral development characteristics were available.Results OrganographyThe inﬂorescences in the three species of Indigofera ana-lysed are densiﬂorous,upright,axillary racemes,approxi-mately 5.0cm long in I.lespedezioides ,8.0cm in I.spicata ,and 4.0cm in I.suffruticosa .The average number of ﬂowers per inﬂorescence is 15in I.les-pedezioides ,14in I.spicata ,and 20in I.suffruticosa .The time from the beginning of raceme development untiltheFigs.29–33Inﬂorescence and early ﬂower development of Indigofera spicata (SEM).Fig.29Inﬂorescence summit in polar view showing helical acropetal order of ﬂoralinitiation.Young ﬂowers have elongating sepals arching over ﬂoral meristem.Fig.30All sepal primordia have initiated in unidirectional order,with last-initiated on adaxial side.Initiation of ﬁrst two petal primordia on abaxial side.Fig.31Initiation of carpel primordium concurrently with the petal primordia.The sepal primordia are converging over the centre of the ﬂower.Fig.32Unidirectional order ofantesepalous stamen primordia.Fig.33Carpel with early cleft (arrow ),after all other ﬂoral organs have initiated.Theadaxial side is on the top and the abaxial side of the ﬂower is on the bottom of the images.Symbols:br bract,c carpel,ip inﬂorescence apex,p petal,s sepal,ap antepetalous stamen,as antesepalous stamen.Scale bars Fig.29=100l m;Figs.30–33=10l mFloral developmental morphology of three Indigofera speciesopening of theﬁrstﬂower of the inﬂorescence is approxi-mately22days in I.lespedezioides,15days in I.spicata and11days in I.suffruticosa.The description ofﬂoral morphology below applies to all three species.Theﬂowers are papilionate and approximately5.0mm long(Figs.1,2,3).The calyx tube hasﬁve short lobes and is persistent(Figs.4,5,6).The vexillum is pink and exhibits variations in the apex morphology(Figs.1,2,3) and nectar-guide colouration among species(Table2);the wings(Figs.7,8,9)are pink,the keels are green(central) and pink(margins)and have a spur(Figs.10,11,12).Nine ﬁlaments are fused to form an adaxially open sheath,and the adaxial stamen of the inner whorl remains free(i.e. diadelphous androecium)(Figs.13,14,15).The anthers are appendiculate and dorsiﬁxed,with longitudinal dehis-cence(Figs.28,41,50)and the anther appendix mor-phology varies among species(Table2).The style is curved and the stigma is minute(Figs.16,17,18),papil-lose,covered by a pellicle and non-secretory trichomes (Figs.28,41,50).The ovary is long-stipitate with linearly arranged ovules and submarginal placentation.An intra-staminal nectariferous disk is present at the base of the ovary stipe.The nectar-guide colour,the non-secretory trichome distribution and quantity,and the anther appendix form vary among species(Table2).OrganogenyThe inﬂorescence is subtended by twoﬁrst-order bracts and producesﬂowers in acropetal order.Eachﬂower is sub-tended abaxially by one second-order bract(Figs.19,29,42,51,52,53).No bracteoles were initiated.Before any organs are initiated,theﬂoral apex is convex and exhibits variation in shape among species:it is elliptic in Indigofera lespedezioides(Figs.19,54)and circular in I.spicata (Figs.29,55)and I.suffruticosa(Figs.42,56).The bracts are elongated in the early stage of development,covering and protecting theﬂoral organ primordia and youngﬂowers (Fig.51,52,53).The order of primordia initiation in vertical succession is ans of each whorl alternate with those of adjacent whorls(Figs.24,35,47).In transverse succession, the sepal primordia are initiated in unidirectional order. Theﬁrst sepal is formed on the abaxial side,followed by two lateral sepal primordia close to theﬁrst,and the last two arise on the adaxial side(Figs.20,21,30,31,43).In Indigofera spicata,the two abaxial sepal primordia are widely separated during their initiation,exposing the location where the adaxial petal primordium(vexillum) will initiate(Figs.33).Petal(Figs.22,30,31,44)and the outer and inner stamen primordia are also initiated unidi-rectionally(Figs.23,24,32,33,46,47).The carpel pri-mordium in I.lespedezioides and I.spicata arises as a central protuberance concurrently with the petal primordia (Figs.22,23,31,32)in I.suffruticosa,the carpel arises soon after petal initiation or concurrently with the ante-sepalous stamen primordia(Fig.45).The carpel cleft is longitudinal and adaxial(Figs.27,40,47,48).It becomes distinguishable after the formation of theﬁve sepals and is closed only after the formation of all other organs (Figs.27,40,48).The anatomical sections assessed show that sepal pri-mordia of I.lespedezioides and I.suffruticosa initiated in a subdermal layer(L2)by periclinal divisions(Fig.57,Table2Diagnostic characters ofﬂoral development and morphology in Indigofera lespedezioides,I.spicata,and I.suffruticosa Stages Characters I.lespedezioides I.spicata I.suffruticosaEarlier stages Form ofﬂoral apex Elliptic(Figs.19,54)Circular(Figs.29,55)Circular(Figs.42,56)Carpel initiation Concurrently with petalinitiation Concurrently with petalinitiationAfter petal initiation or concurrentlywith stamen initiationAnatomical origin of sepals First periclinal divisions inlayer L2First periclinal divisionsin layers L2and L3First periclinal divisionsin layer L2Anatomical origin of antesepalous stamens First periclinal and obliquedivisions in layer L2First periclinal divisionsin layer L3First periclinal divisionsin layers L3and L4Mid stages Carpel elongation Concurrently with the otherﬂoral organsPrecocious PrecociousOrganography Nectar-guide colouration White Pink GreenVexillum apex form Slightly acuminate Slightly emarginate RoundishTrichomes on the anthers Some,on base Two,on base Some,on the dehiscence zoneAnther appendix form Slightly inclined to ventralside Slightly inclined to dorsalsideSlightly inclined to ventral sideTrichomes on carpel Cleft(Fig.28)Lateral zone(Fig.41)Cleft(Fig.50)J.V.Paulino et al.59),in I.spicata the sepal primordia initiate in the sub-dermal layers (L2and L3)by periclinal divisions (Fig.58).The petal primordia (Fig.60,61,62)of all three species start in a subdermal layer (L2)by periclinal divisions.The antesepalous stamen primordia of I.les-pedezioides are initiated in a subdermal layer (L2)by periclinal and oblique divisions,followed by anticlinal divisions in layer L1(Fig.63).In I.spicata,they start deep in a subdermal layer (L3)by periclinal divisions (Fig.64),and in I.suffruticosa they are initiated from much deeper in the subdermal layers (L2,L3,and L4)by periclinal divisions (Fig.65).The layer of origin (depth)and the types of cell divisions of antepetalous stamen andcarpel primordial were not observed.The ovule primordia arise before the carpel cleft is closed,and,consequently,the carpel is open at this stage (Fig.66,67,68).They initiated by periclinal divisions in layer L1,followed by periclinal divisions in deeper layers.Mid and late stages of ﬂoral developmentMid and late stages of ﬂoral development are marked by organ elongation and fusion.The order of organ elongation is as follows:sepal,vexillum,keels plus wings (Figs.25,35),carpel,outer stamens (Figs.28,36,46),and,ﬁnally,innerstamensFigs.34–41Mid and latestages of ﬂoral development of Indigofera spicata (SEM).Fig.34Asymmetric sepal elongation with the abaxial one the longest.Fig.35Carpel with early cleft (arrow ),after all other ﬂoral organs have initiated.The vexillum petal (in adaxial median position)enlargesprecociously compared with the other petals.Fig.36Elongated carpel with visible cleft (arrow ).Fig.37Keel fusion,and carpel elongation.Fig.38Enlarged and differentiated keel petals showing spurs (arrow ).Fig.39Stamen differentiation hasproduced anthers and ﬁlaments.Diadelphous androecium (arrow )elongation.Fig.40Gynoecium has elongated,its cleft is sealed (white arrow ),and its style has become arched over (black arrow ).Fig.41Flower showing non-secretory trichome on the carpel side and papillose stigma (arrow ).Symbols:as antesepalousstamen,ap antepetalous stamen,c carpel,k keel,s sepal,v vexillum,w wing.Scale bars :Fig.34,Fig.36=10l m;Fig.35=50l m;Fig.37,Fig.40=100l m;38,Fig.39,Fig.41=200l mFloral developmental morphology of three Indigofera species(Figs.26,28,39,41,48,50).In I.spicata ,the sepal elongation is asymmetric because of unequal growth of sepal edges (Fig.34).Five sepals fuse at their base while ﬁve apical lobes remain free (Fig.34).The calyx indumentum is composed of non-secretory trichomes (Fig.4,5,6)that originate by periclinal divisions in the layer L1.The keels fuse along their adjacent borders (Fig.35,37),and a spur is formed in the lateral side of each keel (Fig.38).The fusion of nine ﬁlaments into an adaxially open sheath occurs before the elongation of the inner stamens (Figs.26,39,49).The stamen that remains entirely free is positioned adaxially,near the carpel cleft.The fusion of the carpel cleft starts simultaneously with stamen elongation (Figs.27,40).In the later stages of development,the style bends toward the adaxial side (Figs.28,40,41,50)and soon later,the elongation of the antepetalous stamens is com-pleted (Figs.28,41,50).DiscussionMost of the data obtained here are novel for Indigofera ,which has not been studied in terms of ﬂoral and inﬂo-rescence development,despite being a species-rich genus (Lewis et al.2005).Beside this study,there are only two other mentions of some aspect of ﬂower development for Indigofera :sepal initiation (Prenner 2004a )and diadel-phous symmetrical androecium (Prenner 2004b )in I.ger-ardiana and edge-to-edge fusion of keels in I.heteranthera (Tucker 2003a ).Sepal initiation in the species of Indigofera seemed to exhibit some unusual variations when compared to the unidirectional order of organ initiation considered as a pattern for papilionoids (Tucker 1984).The sepals of I.lespedezioides ,I.spicata ,and I.suffruticosa studied here initiated in a unidirectional order,but in I.gerardiana sepal initiation matched the sequential modiﬁed patternofFigs.42–46Inﬂorescence and early ﬂower development of Indigofera suffruticosa (SEM).Fig.42Inﬂorescence showing helical acropetal initiation of ﬂoral meristems.Fig.43Initiation of ﬁrst three sepal primordia on abaxial side of ﬂoral meristem.Fig.44Initiation of the ﬁrst petalprimordia on abaxial side.Fig.45Overlap in time of initiation of outer abaxial stamenprimordium and two abaxial petal primordia.Fig.46Carpel primordium (polar view)beginning to arch over and carpel cleft (arrow ).All ten stamens in outer and innerwhorls have been initiated.The adaxial side is on the top and the abaxial side of the ﬂower is on the bottom of the images.Symbols:ap antepetalousstamen,as antesepalous stamen,br bract,c carpel,k keel,ip inﬂorescence apex,p petal,s sepal,w wing.Scale bars Fig.42=100l m;Figs.43–45=10l m;Fig.46=50l mJ.V.Paulino et al.Prenner (2004a ).Other orders of sepal initiation (modiﬁed unidirectional,unidirectional from the adaxial towards the abaxial side,sequential,bidirectional,and simultaneous)have been veriﬁed in tribes Dalbergiaeae (Klitgaard 1999;Moc ¸o and Mariath 2009);Swartzieae (Mansano et al.2002;Tucker 2003b ),Desmodieae,Genisteae,Loteae,Mir-belieae,Sophoreae,Thermopsideae,and Vicieae (Prenner 2004a ).Such works clearly indicate that most of the patterns established for papilionoids regarding ﬂoral development should be re-evaluated.Other ﬂoral characters presented variations among spe-cies of Indigofera in,for example,ﬂoral apex shape,ana-tomical origins of some organs,carpel elongation,ﬂower density in the inﬂorescence,nectar-guide coloration,anther appendix forms,apex vexillum form,trichomes on sepals,anthers,and carpel (Table 2),the ratio of inﬂorescence length to the leaf length (Moreira and Tozzi 1997),and the type and distribution of secretory trichomes in the inﬂorescence (Marquiafa´vel et al.2009).Most of these conditions,expressed late in the ﬂoral development,are more variable and better utilised in infra-generic delimi-tation,corroborating the hierarchical-signiﬁcance hypoth-esis proposed by Tucker (1997).Specialisations,for example,spurs in the keels,are produced during the intermediate and last stages of ﬂoral development in Indigofera.According to Schrire et al .(2009),the occurrence of spurs in the petals is a character-state commonly found in members of the tribe Indigofereae and can be seen as a case of parallelism within members of this group.Other taxa that present spurs in petals are Aquilegia (Ranunculaceae),Epimedium (Berberidaceae),Delphinium and Heterotoma (Campanulaceae),and Hale-nia (Gentianaceae)(Soltis et al .2005),here corresponding clearly to morphological convergences.It is possible that the nectar produced in small ﬂowers of Indigofera species is presented to the pollinator through petal spurs.SoltisFigs.47–50Mid and latestages of ﬂoral development of Indigofera suffruticosa (SEM).Fig.47Carpel primordium ﬂattened adaxially,with early cleft (arrow ).All ﬂoral organs initiated.Fig.48Carpel cleft closure (white arrow )andstigma initiation (black arrow ).Fig.49Filament fusion (arrow )and formation of diadelphous androecium.Fig.50Differentiated gynoecium with style curving toward adaxial side,and stamens with anther appendices.Arrow indicates papillose stigma.Symbols:ap antepetalous stamen,as antesepalous stamen,c carpel,k keel,w wing.Scale bars :Fig.47,Fig.49=10l m;Fig.48=50l m;Fig.50=100l mFloral developmental morphology of three Indigofera specieset al.(2005)have previously associated the occurrence of spurs with nectar presentation in Eudicotyledons.Spurs should also be related to the explosive pollen liberation in Indigofera (Endress 1994).Considering that we found simple trichomes covering ovary and style (possibly functioning as sweeping hairs)and that secondary pollen presentation has already been cited for papilionoids (Howell et al.1993;Westerkamp and Weber 1999)and,more speciﬁcally,for members of the Disynstemon ?Indigofereae clade (Schrire et al.2009),this condition deserves better investigation in Indigofera .Some remarkable characteristics found in Indigofera are rarely found in other groups of papilionoids,for example,the early expression of zygomorphy in ﬂoral development (see Prenner 2004a for I.gerardiana ),the precocious ini-tiation of ovules (open carpel)and variations on the depth and type of cell division to form the organ primordia (Tucker 2003a ).Early zygomorphy in Indigofera species results from the order of sepal initiation and unequal sepal elongation.Other papilionoids express zygomorphy late during the petal differentiation or during the upturning of styles and stamens,and even the positioning of the ﬂower can promote zygomorphy (Tucker 2003a ).The open car-pels (ovule initiation before cleft closure)exhibited here in Indigofera is a condition only reported in Aeschynomene americana (Tucker and Kantz 2001),Exostyles venusta (Mansano et al.2002),Mirbelia oxylobioides (Tucker 2006),Dahlstedtia pentaphylla and D.pinnata(TeixeiraFigs.51–65Longitudinal anatomical sections of ﬂoral meristems and ﬂoral organ primordia of Indigoferalespedezioides (Figs.51,54,57,60and 63),I.spicata (Figs.52,55,58,61and 64),and I.suffruticosa (Figs.53,56,59,62and 65).Figs.51–53Inﬂorescences showing helical acropetal initiation of ﬂoral meristems.Figs.54–56Floral meristems before organinitiation.Figs.57–59Initiation of sepal primordia by periclinal divisions in subdermal layers L2and L3(arrows ).Figs.60–62Initiation of petal primordia by periclinal divisions insubdermal layer L2(arrows ).Figs.63–65Initiation ofantesepalous stamen primordia by periclinal divisions (arrow )in subdermal layers L2,L3and L4(arrows ).Scale bars Figs.51–53=100l m;Figs.57–65=10l mJ.V.Paulino et al.。

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In (30) change8 to 2 and 15 to 60. Follon-ing (30), change 15 to 60 in two places, 121to 101, 272 to 250 in two places, and 3.9 to 3.5. The efficiency of the resistive antenna as obtained in the paper is incorrect The correct value may be derived from the ratio of the power dissipated in the resistive antenna to the power radiated. The radiated power P, is obtained by integrating the Poynting vector over a large spherical surface in the far field.
0.3891
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Sidelobe Level
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20
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The Cylindrical Antenna with Nonreflecting Resistive Loading
In the above paper' the authors would like to make the following corrections: following (6). change value to magnitude. I n (29) change l / k h to j / k h . The expressions for 4in lines 3 and 7 on p. 371 should be changed, respectively, to
The otherintegral of (5) was also numerically integrated. This integral is
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Thus.
The sin 2kL term has been dropped. Figure 1, page 492, has been recalculated and is shown here. In the example below the original (S), for a 25-dB source, normalized directivity changes from 0.953 for 1 O X to 0.753 for 1001. The lOOh line source has 21.8dB directivity. 2 also occurs in the compuBecause the 1 tation for the Taylor "approximate" line source, (15) has been corrected also,
Manuscript received July 30. 1965. T. W T. u and R. W. P. King, I E E E T r a m on Antennas and Propagation, vol. ..\P-13. pp. 369373. May 1965.
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EFFICIENCY OF NON-REFLECTING ANTENNA
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NOVEMBER
2
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