Differentiating 180° and 90° switching of ferroelectric domains with three-dimensional

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Using automatic differentiation for adjoint CFD code development

November, 2005
2
1
Introduction
The use of adjoint methods for design optimisation has been a major research area in the last few years. Pironneau ﬁrst introduced the idea of using an adjoint approach in ﬂuid dynamic context [18] but the application to aeronautical design optimisation has been pioneered by Jameson [14, 15, 19]. Jameson uses the “continuous” adjoint approach in which the adjoint equation is formulated at the diﬀerential equation level, and it is then discretised. In contrast to this, Elliott and Peraire [5] and others [1, 9] follow a “discrete” adjoint approach in which one starts with nonlinear discrete equations, and then formulates the corresponding discrete adjoint equations. There is no fundamental reason to prefer one approach over the other. Proponents of the discrete approach sometimes point to the fact that the continuous approach yields a design gradient (the gradient of the objective function with respect to the design variables) which is not quite consistent with the discrete objective function being optimised. However, it is as good an approximation to the true design gradient as the discrete gradient, and provided one uses an optimisation strategy (e.g. preconditioned steepest descent) which simply drives the continuous gradient to zero, then it will yield results as good as the discrete approach. Our strong preference for the discrete approach is pragmatic in nature, and based on the following key points: • There is a clear prescriptive process for constructing the discrete adjoint equations and boundary conditions; • In most cases, if an adjoint iterative solution technique is used then it is guaranteed to give an iterative convergence rate equal to that of the original nonlinear code; • Automatic Diﬀerentiation can be used to substantially ease the development of the adjoint CFD code. The purpose of this paper is to explain these three points, with particular emphasis on the ﬁnal point. One of the earliest applications which motivated the development of “reverse mode” AD (which can stand for either Algorithmic Diﬀerentiation [11] or Automatic Diﬀerentiation [12]) was in ﬂuid dynamics, an adjoint version of an ocean circulation model being developed at MIT [6]. In the aeronautical context, perhaps the ﬁrst application was by Mohammadi [16]. In simple, small applications, it is sometimes possible to use AD as a “black-box”, feeding in a nonlinear code and obtaining a corresponding linear perturbation (forward mode AD) or adjoint (reverse mode AD) code. However, in real applications with very large codes in which one wants to minimise the CPU and memory requirements, it is usually necessary to apply the AD very selectively. This is particularly the case in design optimisation in which one is using a ﬁxed point iteration to solve the original nonlinear equations [7, 8].

Simulations on the electromechanical poling of ferroelectric ceramics

II.
MODEL AND SIMULATIONS
The unpolable ferroelectric ceramics is assumed to be made up of many randomly oriented grains, each grain is ferroelectric tetragonal and single domain. The 900 switching for the tetragonal symmetry is used as a general representative of the non-1800 domain switching in this paper. For a homogeneous ceramics, the Reuss approximation7 is adopted when the material is subjected to the applied electric ﬁeld and stress. The orientation of the grain is 3
Simulations on the electromechanical poling of ferroelectric ceramics
Yin-Zhong Wu and Yong-Mei Tao
arXiv:0712.0854v1 [cond-mat.mtrl-sci] 6 Dec 2007
Jiangsu Laboratory of Advanced Functional materials, and Department of Physics, Changshu Institute of Technology, Changshu 215500, P. R. China∗

VW80972_EN_2009-11-01

Infotainment SystemsGeneral Functional RequirementsPrefaceToday, specific performance specifications are available for all new infotainment projects, defining requirements on a project-specific basis. In order to avoid confusion and ambiguity, these require‐ments will be removed from this standard (in compliance with the CC Radio/Tuner decision of January 14, 2008) which will be limited to more general issues. Only the methods and measurement proce‐dures used to determine the characteristic values of the specific requirements will be described.Previous issuesTL 972: 1995-07; VW 80972: 2000-07, 2001-10, 2006-09ChangesThe following changes have been made as compared to VW 80972: 2006-09:–Title changed–Scope: extended to include all infotainment systems–Release testing: extended and divided into field testing and laboratory testing with references tospecific performance specifications –Definitions: supplemented–Editorial: Replacement of term LF (low frequency) by audio operating modes and descriptionaccording to definiton in VW 80101–Environmental requirements supplemented–Preferred measurement frequency: AM harmonized for NAR and EU–Temperature requirements: Section 8.2.1.1 Audio continuous power, system cooling divided into5.2.3.1 System cooling and 8.2.1.1 Audio continuous power; further installation locations andcontrol elements added and temperature stages test addedGroup StandardVW 80972Issue 2009-11Class. No.:8FL40Descriptors:car radio, radio, radio navigation systems, infotainment modules, infotainment, audio systems, mediaCheck standard for current issue prior to usage.This electronically generated standard is authentic and valid without signature.The English translation is believed to be accurate. In case of discrepancies the German version shall govern.Numerical notation acc. to ISO practice.Page 1 of 39Technical responsibility Standards Department EEFI/3Detlev BeyerTel.: +49-5361-9-23881EKDV/4 Dirk Beinker EKDVTel.: +49-5361-9-32438Manfred TerlindenConfidential. All rights reserved. No part of this document may be transmitted or reproduced without prior permission of a Standards Department of the Volkswagen Group.Parties to a contract can only obtain this standard via the B2B supplier platform .© Volkswagen AktiengesellschaftVWNORM-2008-12hPage 2VW 80972: 2009-11–EMC approval: Individual standards removed and reference to Volkswagen Component Perfor‐mance Specifications Template for EMC module added–Illumination: Reference to Performance Specifications on Illumination (of Display and Control Elements in the Passenger Compartment) added–Antenna remote supply: AM/FM harmonized with DAB, SDARS complemented–Operating temperatures: CompactCassette (CC) and MiniDisk (MD) withdrawn–Operating noise: CC and MD withdrawn, DVD added–Test sequence: Table 3 updated–Mechanics requirements: Reference to …MIB_Device_Mechanics_Main_Unit“, Chapter 4 "Tech‐nical Requirements"; load cycle quantity deleted–Actuation forces: keys, values revised–Endurance test: Output power increased and radio extended to 1000 h–Voltages: Functional states, editorial revision, supplements and revision of "after end of functional state D"–Voltage dip: requirements complemented–Interruption: conditions after functional state added–Interference immunity: operating voltages quickly changing in time added–Switching behavior, ON/OFF: reference to MIB power management performance specifications added–Control input/output: MOST reference added to CAN performance specifications–Audio requirements: Reference to performance specifications …MIB_RQ_List_Sound“ added and note on common mode rejection for voltage changes added–Audio phase position AM/FM new–Common mode rejection: values revised–Audio source level plan: generalized, only refers to basic sources–BOSE®: deleted–Other sound systems: new description: sound systems, "branded"–Audio outputs: Values adapted–Frequency responses: Measurement conditions for different sources combined and reference to performance specifications "MIB_RQ_List_Sound" added–Control capacity of ...: merged and reference to performance specifications "MIB_RQ_List_Sound" added–Audio inputs: values adapted–CC drive requirements: removed–MD drive requirements: removed–CD, DVD audio,...: combined in the media Section and reference to performance specifications added–CD, DVD, HDD drive requirements revised with regard to mechanics and performance require‐ments described in VDA guideline 240-300 and in the "Test Case Book for Automotive Drives".–Video requirements: new–Navigation requirements new–Road test: text on assessment revised–Table 1: deleted, integrated in radio sections–Laboratory testing: operating noise and rattling added– 5.1.2 Operating temperatures: text complemented– 5.3.4 System temperature management : Text complemented– 5.5 Illumination: only reference to: display illumination performance specifications– 5.7 Chemical requirements: listing of individual substances omitted, only reference to VW 80101,a), o) and q) deleted– 5.11 Operating noise: details complemented– 6. Mechanical Requirements: All individual points deleted, only reference to performance spe‐cifications, VW80101 and performance specifications module "Testing"– 5. General requirements: Reference to other requirement areas according to VW 80101– 5.1.2 Temperature requirements complemented– 5.7 Resistance to light complemented, distinction of materials– 5.8 Test sequence: table removed, reference to MQB test performance specifications– 5.10 Operating noise: reference to VW 82469, "Accessory Equipment; Acoustic Requirements"–7.1 Adjustable frequency ranges: table removed and references created –7.2 Voltages: adapted to new values from AK 4.14–7.8 Irritating noise: control elements reintegrated and headline errors revised –12. Telephone requirements: reference to performance specifications–13. Radio requirements: reference to performance specifications and radio sections of this stan‐dard–New limit values more suitable for practical use for: 8.2.6 THD against power; 8.7 Audio inputs S/N; 9.3.1.3 Channel separation –EMC references revised–Audio requirements: changed name of performance specifications adopted –7.4.2.3 Antenna supply: current limitation added–8.5 Reception-quality-dependent sound influence: deleted, reference to "MIB_RQ_Radio_AM-FM-IBOC"ContentsPageScope .............................................................................................................................5Terms .............................................................................................................................6General descriptions: .....................................................................................................6Broadcasting terms for radio wave ranges depending on wave length .........................6Higher-level regulations and guidelines .........................................................................7Regulations ....................................................................................................................7Applicable laws and regulations .....................................................................................7EMC approval ................................................................................................................8Environmental requirements ..........................................................................................8General test conditions ..................................................................................................8Voltage source ...............................................................................................................8Test temperature ............................................................................................................9Preferred measurement frequencies .............................................................................9Modulation .....................................................................................................................9Note .............................................................................................................................10Identification of devices ................................................................................................10Test frames (schematic description) . (10)122.12.233.13.23.33.444.14.24.34.44.54.64.7Page 3VW 80972: 2009-11Operating modes (extract from VW 80101, Operating modes) ....................................10General requirements ..................................................................................................11Release testing ............................................................................................................11Road test ......................................................................................................................11Laboratory testing ........................................................................................................12Temperature requirements ..........................................................................................12Operating temperatures ...............................................................................................13Multi-stage temperature test ........................................................................................13Temperature resistance ..............................................................................................13Conditioning (forced-air aging, without load) ...............................................................13Temperature cycle (no load) ........................................................................................14Rapid temperature cycle with specified transfer duration (thermal shock test) ............14System temperature management ...............................................................................14Resistance to humid/warm environments (cyclic) ........................................................15Illumination/nighttime design ........................................................................................16Control elements (buttons and trim) .............................................................................16Chemical requirements (resistance to chemical agents) .............................................16Lightfastness ................................................................................................................16Test sequence .............................................................................................................16Flammability .................................................................................................................16Operating noise ............................................................................................................16Noise limit values during excitation (rattling and squeaking) .......................................17Mechanical requirements .............................................................................................17Requirements for electric system .................................................................................17Frequency ranges that can be selected .......................................................................17Voltages .......................................................................................................................18Overvoltage strength ....................................................................................................19Testing at 10,8 V ..........................................................................................................19Voltage dip, brief period (starting pulse) ......................................................................19Interruption ...................................................................................................................19Reverse polarity protection ..........................................................................................20Current .........................................................................................................................20Maximum permissible closed-circuit current/power consumption ................................20Control lines (capacity) ................................................................................................20Overcurrent strength ....................................................................................................22Switching behavior, ON/OFF .......................................................................................22Control inputs ...............................................................................................................22PHONE (analog input) .................................................................................................22S contact (analog input) ...............................................................................................22Illumination ...................................................................................................................23Speed-dependent volume control ................................................................................23Frequency constancy ...................................................................................................23Station frequency repeatability .....................................................................................23Frequency drift upon change in ambient temperature .................................................23Frequency drift upon changes in operating voltage .....................................................24Interferences ................................................................................................................24Interferences caused by control elements ...................................................................24Interference caused by internally generated auxiliary operating frequencies orcheck routines ..............................................................................................................24Interference due to internal drives (CD, DVD, SD and HDD) ......................................25Interference immunity ..................................................................................................25Ignition interference .. (25)4.855.15.1.15.1.25.25.2.15.2.25.35.3.15.3.25.3.35.3.45.45.55.65.75.85.95.105.115.12677.17.27.37.3.17.3.27.3.37.3.47.47.4.17.4.27.4.37.57.67.6.17.6.27.6.37.6.47.77.7.17.7.27.7.37.87.8.17.8.27.8.37.97.9.1Page 4VW 80972: 2009-11Electric system interference .........................................................................................25Interference caused by alternator ................................................................................25Electrostatic charging protection ..................................................................................26Audio requirements ......................................................................................................26Audio source level plan (objective: lowest possible subjective volume difference)......................................................................................................................................26Audio outputs ...............................................................................................................27Audio outputs for passive speaker systems .................................................................27Audio outputs for sound systems (line/AUX out, rear seat entertainment) ..................28Audio outputs for sound systems with full level input ...................................................29Audio background noise ..............................................................................................29Clipping ........................................................................................................................29THD against power ......................................................................................................29Volume range ...............................................................................................................30Audio phase position at FM and AM ............................................................................30Audio frequency response ..........................................................................................30Loudness .....................................................................................................................31Vehicle-specific sound curve, frequency response for traffic audio memory ...............31Control capacity of the volume, geometry and bass/treble controls ............................31Reception-quality-dependent sound influence for FM .................................................31Speed-dependent corrections of the audio signal ........................................................31Audio inputs .................................................................................................................31Stereo input for external media ....................................................................................31Stereo input for external media (AUX) .........................................................................32Audio input for telephone .............................................................................................32Media AUDIO requirements .........................................................................................32Cassette operation, cassette drive requirements .........................................................32MiniDisc operation (MD requirements) ........................................................................32CD, DVD, HDD and SD operation ...............................................................................32CD playback requirements ...........................................................................................33Memory cards ..............................................................................................................34Hard disk drives (HDD) as audio source ......................................................................36Video requirements ......................................................................................................37TV requirements ..........................................................................................................37Navigation requirements ..............................................................................................37Telephone requirements ..............................................................................................37Radio requirements ......................................................................................................37Radio requirements EUROPA, CHINA and ROW .......................................................38Radio requirements, JAPAN ........................................................................................38Radio requirements North America / Latin America .....................................................38Referenced documents ................................................................................................38Bibliography .................................................................................................................397.9.27.9.37.1088.18.28.2.18.2.28.2.38.2.48.2.58.2.68.2.78.2.88.38.3.18.3.28.48.58.68.78.7.18.7.28.7.399.19.29.39.3.19.3.29.3.31010.111121313.113.213.31415ScopeThis standard specifies requirements and tests for all infotainment systems implemented within the Volkswagen Group and associated components (radios, navigation systems, media player, audio amplifiers,...).The relevant version valid at the time the order is placed applies to corresponding standards and regulations.1Page 5VW 80972: 2009-11The performance specifications (German abbreviation LAH) specified in this standard are exemplary and must be specifically adapted for other projects. The compliance with the respective component performance specifications (German abbreviation BT-LAH) and with this standard are prerequisites for technical engineering approval (BMG) and the resulting component release.TermsGeneral descriptions:AU-S Function description AU dio S ound OMO perating M odeControl elementsAll elements (keys, knobs, display and media) which must be used for oper‐ation, use or control of the systemUser-accessible areas All areas that can be touched voluntarily or involuntarily by the user withoutremoving installation, add-on, trim or protection elementsBMG Technical Engineering Approval (German abbreviation)BT-LAH Component Performance Specifications (German abbreviation)CRIN Description in ISO for C ar R adio I dentification N umber HW H ard W are LCD L iquid C rystal D isplay (display type)LSM L ast S ituation M emory ROW "R est o f W orld", applies to requirements not assigned to specific regions RT R oom T emperature SW S oft W are TFT T hin F ilm T ransistor (display type)Calibration value Measured value in as-delivered condition before carrying out any test thatmay have an influenceHead impact Simulation of a collision in which the front seat passengers' heads hit thedashboard.KAF Volkswagen group acceptance test drive (German abbreviation)Functional statuses See VW 80101, Section on functional states Broadcasting terms for radio wave ranges depending on wave lengthAMA mplitude M odulation, also MFLimitation Compensation of audio level fluctuations depending on the reception level DAB Digital Audio Broadcasting (digital radio)dB Unit of measure for the logarithmic relationship of levels dBµV Logarithmic level relationship with the reference value 1µVE´RF level at antenna input downstream of the antenna simulation E´R RF level for noise-limited sensitivity f N Frequency of the desired station f S Frequency of the interfering stationf nnth transmitter in multiple-transmitter measuring methods2 2.12.2 Page 6VW 80972: 2009-11FM F requency M odulation, also VHF VHF V ery H igh F requency, also FMFS "F ull S cale" reference full level CD 0 dB (full modulation amplitude)RF R adio F requency, frequencies > 100 kHz k maxMaximum nonlinear distortion factorNonlinear distortion factor Degree of nonlinear audio distortions, indicated in %SW S hort W aveL Left stereo channel LW L ong W avem Modulation level for AM modulations in %MW M edium W ave, also AMLFL ow F requency, audio frequency range, 20 Hz to 20 kHz Desired station Station tuned in to listen to P LFAudio output powerRRight stereo channelStereo2-channel sound playbackInterfering station The station influencing the desired station T HS Temperature on heat sinkT CE Temperature of trim/control elementsU B Battery voltage/operating voltage at the control unit's connection block U Ant Antenna operating voltage at the antenna jackU A RF output level at signal generator upstream of antenna simulation Δf Modulation shift for FM modulations in kHzHigher-level regulations and guidelines RegulationsUnless other requirements exist, the standard production devices must comply with the specifications of the respective national governmental approval agency.The manufacturer is responsible for proof of compliance.Applicable laws and regulationsPassenger compartment (interior trim)ECE R21 [1]Passenger compartment (head impact)EC 74/60 EEC [2]Electromagnetic compatibility ECE R101) [3]Electromagnetic compatibilityEC GL 2006/96/EC [4]Presentation for type approval for the passenger compartment specifications to the releasing gov‐ernment authority is carried out and released by the responsible department of the respective cor‐porate brand in the scope of the vehicle type approval process.3 3.13.21)This is covered by the Volkswagen Group in the EMC type approval. For the original equipment, use in the vehicle manufacturing plant,neither an e nor an E nor a CE marking is required.Page 7VW 80972: 2009-11EMC approvalFor original use, an EMC approval is carried out by the Volkswagen AG specialized departments in the scope of the vehicle type approval process.Compliance with the applicable EMC guidelines according to "VW Component Performance Specifi‐cations Template Module for EMC" [5] is absolutely necessary for this.For EMC testing, all sample versions starting from the basic sample must be submitted to the re‐sponsible department including complete documentation and measurement protocols. For EMC re‐lease, three sample devices representing the standard production status have to be presented. After successful release, these devices must be stored as confirmed reference samples, one device at the department carrying out the EMC release, one at the development release department and one at the manufacturer.Environmental requirementsCompliance with the Group requirements for the manufacture of the devices and the choice of the materials must be ensured.–VW 91100 "Environmental Standard for Vehicles; Vehicle Parts, Materials, Operating Fluids;Policy, Specifications"–VW 91101 "Environmental Standard for Vehicles Vehicle Parts, Materials, Operating Fluids Avoidance of Hazardous Substances"–VW 91102 SUPPLEMENT 3 "Environmental Standard for Vehicles;Requirements for a Process‐ing Concept"–VW 91102 "Environmental Standard for Vehicles; Recycling Requirements, Use of Recycled Material, Type Approval with Regard to Recyclability"–VW 91104 "Vehicle Environmental Standard; Basics, Technical Inventory Analysis, Life Cycle Inventory Analysis"–VDA 260 "Motor Vehicle Components; Marking of Materials"Compliance must be documented by the manufacturer by means of a hazardous-substance docu‐mentation list including quantity data for the hazardous substances contained in the product.General test conditionsAll DUTs must comply with the requirements specified in VW 80101. All parts must completely fulfill their specified function both during and after the tests, unless these are destructive tests. The re‐quirements apply to the entire operating voltage and operating temperature ranges.During the tests, the DUTs must be continuously monitored using suitable monitoring devices with test cycles adapted to the requirements and the operating states.For test procedure, number and sequence, see test performance specifications. See also Section 5.9 for further notes.Voltage sourceTest voltage14V ± 0,1 V, terminal voltage at the device Internal resistance< 0,1 ΩReference output power0,5 W at load simulation of 4 Ω3.3 3.444.1Page 8VW 80972: 2009-11Test temperatureAll limits and parameters according to the valid specifications must be adhered to within the test temperature range.Temperature range: -30 °C to +70 °CFurther "special" temperatures are indicated in the relevant Sections and must be taken into consid‐eration.A tolerance of ± 2 °C applies to all temperatures.Measurements for which no temperature is specified are to be performed at RT ≙ 23 °C ± 5 °C according to DIN.Preferred measurement frequenciesThe following measurement frequencies and modulations are given as an orientation and as default settings for the tests and requirements specified in Section 5 onwards. Location-specific changes required due to local transmitters must be documented.Deviating modulation signals for source differentiation when carrying out the reliability tests are per‐mitted.Table 1LW 153183252 kHz AM(MW)54010801440 kHz SW 6,1 MHz FM 89,194,199,1106,1MHz FM 79,582,586,589,5MHz JapanDAB 174,928216,928223,936239,200BAND III EUROPE/CANADA DAB 1452.9601471.7921490.624 L-BAND EUROPE/CHINA DAB 1452.8161472.0001491.184L-BAND CANADA DAB tbdBand III, CHINA SDARSall reception paths (terrestrial and SAT)North AmericaDRM / IBOC analogous to AM and FM ModulationAM:1000 Hz Modulation signal 30 %Degree of modulation FM:1000 HzModulation signal ± 40 kHzFrequency shift Additionally for stereo:19 KHzPilot signal± 7,5 KHzFrequency shift Additionally for RDS:57 KHzPilot signal± 2 KHzFrequency shift4.2 4.34.4 Page 9VW 80972: 2009-11。

中西方吉凶数字差异英语作文

中西方吉凶数字差异英语作文The Contrasting Significance of Lucky and Unlucky Numbers in Eastern and Western CulturesThe concept of lucky and unlucky numbers is a fascinating aspect of cultural diversity, with distinct perspectives between Eastern and Western societies. While some numbers are revered as auspicious in one part of the world, they may be viewed as inauspicious in another. This contrast in the symbolic meaning of numbers reflects the unique histories, beliefs, and traditions that have shaped the worldviews of different civilizations.In the Eastern hemisphere, particularly in countries like China, Japan, and Korea, the number 8 is widely regarded as a symbol of good fortune and prosperity. This is primarily due to the fact that the Chinese word for "eight," ba, sounds similar to the word for "wealth" or "prosperity," fa. The number 8 is also associated with the idea of infinity and considered to be a balanced and harmonious digit. As a result, the number 8 is often featured prominently in important events, addresses, and even product prices, as it is believed to bring luck and success.On the other hand, the number 4 is often viewed as an unlucky number in East Asian cultures. This is because the Chinese word for "four," si, is phonetically similar to the word for "death," which can be seen as an ominous association. In some instances, the number 4 is actively avoided, with buildings and floors sometimes skipping the fourth floor altogether. The superstition surrounding the number 4 has even extended to the business world, where some companies may refrain from using the number in their product names or pricing.In contrast, Western societies, particularly those with a Judeo-Christian heritage, tend to have a different set of beliefs regarding lucky and unlucky numbers. The number 13 is often considered an unlucky number in the West, with the origins of this superstition rooted in biblical and mythological traditions. For example, in the Bible, Judas, the disciple who betrayed Jesus, was the 13th member to join the Last Supper. Additionally, the number 13 is associated with the Norse god Loki, who was the 13th guest to arrive at a dinner party where he caused mischief and chaos.The fear of the number 13, known as "triskaidekaphobia," has had a significant impact on Western culture, with some buildings omitting the 13th floor and many people avoiding scheduling important events or activities on the 13th of the month. The number 7, on the other hand, is often viewed as a lucky number in Western cultures, with numerous references to its significance in religious texts,literature, and popular culture.The contrasting significance of lucky and unlucky numbers in Eastern and Western cultures can be attributed to a variety of historical, religious, and cultural factors. In the East, the emphasis on harmony, balance, and the cyclical nature of life has influenced the positive connotations associated with numbers like 8, while the negative perception of 4 reflects the desire to avoid inauspicious associations.In the West, the Judeo-Christian tradition and the influence of mythology have contributed to the superstitions surrounding the number 13, while the significance of the number 7 is often linked to its prevalence in religious and mythological narratives.These cultural differences in the perception of lucky and unlucky numbers have practical implications as well. For example, when conducting business or planning events in a cross-cultural context, it is important to be mindful of these numerical associations and preferences to avoid potential misunderstandings or offenses.In conclusion, the contrasting significance of lucky and unlucky numbers in Eastern and Western cultures is a fascinating aspect of our global diversity. By understanding these differences, we can gain insights into the unique worldviews and belief systems that have shaped the perspectives of various civilizations. Embracing andrespecting these cultural nuances can foster greater cross-cultural understanding and appreciation, ultimately enriching our shared human experience.。

电工英语词汇

电路的基本概念及定律电源source [sɔ:s]电压源voltage source电流源current source理想电压源ideal voltage source理想电流源ideal current source伏安特性volt-ampere characteristic电动势electromotive force电压voltage['vəultidʒ]电流current['kʌrənt]电位potential[pəu'tenʃəl]电位差potential difference欧姆Ohm伏特Volt安培Ampere瓦特Watt焦耳Joule电路circuit电路元件circuit element电阻resistance电阻器resistor电感inductance电感器inductor电容capacitance电容器capacitor电路模型circuit model参考方向reference direction 参考电位reference potential欧姆定律Ohm’s law基尔霍夫定律Kirchhoff’s law基尔霍夫电压定律Kirchhoff’svoltage law（KVL）基尔霍夫电流定律Kirchhoff’scurrent law（KCL）结点node支路branch回路loop网孔mesh支路电流法branch current analysis网孔电流法mesh current analysis 结点电位法node voltage analysis 电源变换source transformations叠加原理superposition theorem网络network无源二端网络passive two-terminal network有源二端网络active two-terminal network戴维宁定理Thevenin’s theorem诺顿定理Norton’s theorem开路（断路）open circuit短路short circuit开路电压open-circuit voltage短路电流short-circuit current交流电路直流电路direct current circuit (dc)交流电路alternating current circuit (ac)正弦交流电路sinusoidal a-c circuit平均值average value有效值effective value均方根值root-mean-squire value (rms)瞬时值instantaneous value电抗reactance感抗inductive reactance容抗capacitive reactance法拉Farad亨利Henry阻抗impedance复数阻抗complex impedance相位phase初相位initial phase相位差phase difference相位领先phase lead相位落后phase lag倒相，反相phase inversion频率frequency角频率angular frequency 赫兹Hertz相量phasor相量图phasor diagram有功功率active power无功功率reactive power视在功率apparent power功率因数power factor功率因数补偿power-factor compensation串联谐振series resonance并联谐振parallel resonance谐振频率resonance frequency频率特性frequency characteristic 幅频特性amplitude-frequencyresponsecharacteristic相频特性phase-frequencyresponsecharacteristic截止频率cutoff frequency品质因数quality factor通频带pass-band带宽bandwidth (BW)滤波器filter一阶滤波器first-order filter二阶滤波器second-order filter低通滤波器low-pass filter高通滤波器high-pass filter带通滤波器band-pass filter带阻滤波器band-stop filter转移函数transfer function波特图Bode diagram傅立叶级数Fourier series三相电路三相电路three-phase circuit三相电源three-phase source对称三相电源symmetricalthree-phasesource对称三相负载symmetrical three-phase load相电压phase voltage相电流phase current线电压line voltage线电流line current三相三线制three-phase three-wire system三相四线制three-phase four-wire system三相功率three-phase power星形连接star connection(Y-connection)三角形连接triangularconnection( -connection ,deltaconnection)中线neutral line 电路的暂态过程分析暂态transient state稳态steady state暂态过程，暂态响应transient response换路定理low of switch一阶电路first-order circuit三要素法three-factor method时间常数time constant积分电路integrating circuit微分电路differentiating circuit磁路与变压器磁场magnetic field磁通flux磁路magnetic circuit磁感应强度flux density磁通势magnetomotive force磁阻reluctance电动机直流电动机dc motor交流电动机ac motor异步电动机asynchronous motor同步电动机synchronous motor三相异步电动机three-phaseasynchronousmotor单相异步电动机single-phaseasynchronousmotor旋转磁场rotating magnetic field 定子stator转子rotor转差率slip起动电流starting current起动转矩starting torque额定电压rated voltage额定电流rated current额定功率rated power机械特性mechanical characteristic继电器-接触器控制按钮button熔断器fuse开关switch行程开关travel switch继电器relay接触器contactor常开(动合)触点normally open contact常闭(动断)触点normally closed contact时间继电器time relay热继电器thermal overload relay中间继电器intermediate relay可编程控制器（PLC）可编程控制器programmable logic controller语句表statement list梯形图ladder diagram半导体器件本征半导体intrinsic semiconductor掺杂半导体doped semiconductor P型半导体P-type semiconductor N型半导体N--type semiconductor自由电子free electron空穴hole载流子carriersPN结PN junction扩散diffusion漂移drift二极管diode硅二极管silicon diode锗二极管germanium diode阳极anode阴极cathode发光二极管light-emitting diode (LED)光电二极管photodiode稳压二极管Zener diode晶体管（三极管）transistor PNP型晶体管PNP transistor NPN型晶体管NPN transistor发射极emitter集电极collector基极base电流放大系数current amplification coefficient场效应管field-effect transistor (FET)P沟道p-channelN沟道n-channel结型场效应管junction FET （JFET）金属氧化物半导体metal-oxide semiconductor (MOS)耗尽型MOS场效应管depletion mode MOSFET（D-MOSFET）增强型MOS场效应管enhancement mode MOSFET （E-MOSFET）源极source栅极grid漏极drain跨导transconductance夹断电压pinch-off voltage热敏电阻thermistor开路open短路shorted基本放大器放大器amplifier正向偏置forward bias 反向偏置backward bias静态工作点quiescent point (Q-point)等效电路equivalent circuit电压放大倍数voltage gain总的电压放大倍数overall voltage gain饱和saturation截止cut-off放大区amplifier region饱和区saturation region截止区cut-off region失真distortion饱和失真saturation distortion截止失真cut-off distortion零点漂移zero drift正反馈positive feedback负反馈negative feedback串联负反馈series negative feedback并联负反馈parallel negative feedback共射极放大器common-emitter amplifier射极跟随器emitter-follower共源极放大器common-source amplifier共漏极放大器common-drain amplifier多级放大器multistage amplifier 阻容耦合放大器resistance-capacitance coupled amplifier直接耦合放大器direct- coupled amplifier输入电阻input resistance输出电阻output resistance负载电阻load resistance动态电阻dynamic resistance负载电流load current旁路电容bypass capacitor耦合电容coupled capacitor直流通路direct current path交流通路alternating current path 直流分量direct current component交流分量alternating current component变阻器（电位器）rheostat电阻（器）resistor电阻（值）resistance电容（器）capacitor电容（量）capacitance电感（器，线圈）inductor电感（量），感应系数inductance 正弦电压sinusoidal voltage集成运算放大器及应用差动放大器differential amplifier 运算放大器operational amplifier(op-amp)失调电压offset voltage失调电流offset current共模信号common-mode signal差模信号different-mode signal共模抑制比common-mode rejection ratio (CMRR)积分电路integrator（circuit）微分电路differentiator（circuit）有源滤波器active filter低通滤波器low-pass filter高通滤波器high-pass filter带通滤波器band-pass filter带阻滤波器band-stop filter波特沃斯滤波器Butterworth filter切比雪夫滤波器Chebyshev filter 贝塞尔滤波器Bessel filter截止频率cut-off frequency上限截止频率upper cut-off frequency下限截止频率lower cut-off frequency中心频率center frequency带宽Bandwidth开环增益open-loop gain闭环增益closed-loop gain共模增益common-mode gain输入阻抗input impedance电压跟随器voltage-follower电压源voltage source电流源current source单位增益带宽unity-gain bandwidth频率响应frequency response频响特性（曲线）response characteristic波特图the Bode plot稳定性stability补偿compensation比较器comparator迟滞比较器hysteresis comparator 阶跃输入电压step input voltage仪表放大器instrumentation amplifier隔离放大器isolation amplifier对数放大器log amplifier反对数放大器antilog amplifier反馈通道feedback path反向漏电流reverse leakage current相位phase相移phase shift锁相环phase-locked loop(PLL)锁相环相位监测器PLL phase detector和频sum frequency 差频difference frequency波形发生电路振荡器oscillatorRC振荡器 RC oscillatorLC振荡器 LC oscillator正弦波振荡器sinusoidal oscillator三角波发生器triangular wave generator方波发生器square wave generator 幅度magnitude电平level饱和输出电平（电压）saturated output level功率放大器功率放大器power amplifier交越失真cross-over distortion甲类功率放大器class A power amplifier乙类推挽功率放大器class B push-pull power amplifierOTL功率放大器output transformerless power amplifier OCL功率放大器output capacitorless power amplifier直流稳压电源半波整流full-wave rectifier全波整流half-wave rectifier电感滤波器inductor filter电容滤波器capacitor filter串联型稳压电源series (voltage) regulator开关型稳压电源switching (voltage) regulator集成稳压器IC (voltage) regulator 晶闸管及可控整流电路晶闸管thyristor单结晶体管unijunction transistor （UJT）可控整流controlled rectifier可控硅silicon-controlled rectifier 峰点peak point谷点valley point控制角controlling angle导通角turn-on angle门电路与逻辑代数二进制binary二进制数binary number十进制decimal十六进制hexadecimal二-十进制binary coded decimal （BCD）门电路gate三态门tri-state gate与门AND gate或门OR gate非门NOT gate与非门NAND gate 或非门NOR gate异或门exclusive-OR gate反相器inverter布尔代数Boolean algebra真值表truth table卡诺图the Karnaugh map逻辑函数logic function逻辑表达式logic expression组合逻辑电路组合逻辑电路combination logic circuit译码器decoder编码器coder比较器comparator半加器half-adder全加器full-adder七段显示器seven-segment display时序逻辑电路时序逻辑电路sequential logic circuitR-S 触发器R-S flip-flopD触发器 D flip-flopJ-K触发器J-K flip-flop主从型触发器 master-slave flip-flop置位set复位reset直接置位端direct-set terminal直接复位端direct-reset terminal寄存器register移位寄存器shift register双向移位寄存器bidirectional shift register计数器counter同步计数器synchronous counter 异步计数器asynchronous counter 加法计数器adding counter减法计数器subtracting counter 定时器timer清除（清0）clear载入load时钟脉冲clock pulse触发脉冲trigger pulse上升沿positive edge下降沿negative edge时序图timing diagram波形图waveform脉冲波形的产生与整形单稳态触发器monostable flip-flop双稳态触发器bistable flip-flop无稳态振荡器astable oscillator晶体crystal555定时器555 timer模拟信号与数字信号的相互转换模拟信号analog signal数字信号digital signal AD转换器analog -digital converter (ADC)DA转换器digital-analog converter (DAC)半导体存储器只读存储器read-only memory （ROM）随机存取存储器random-access memory（RAM）可编程ROM programmable ROM （PROM）。

THS3092DDA,THS3096PWP,THS3092DDAR,THS3092DDARG3,THS3092DG4,THS3096DG4, 规格书,Datasheet 资料

PART NUMBER THS3092D THS3092DR THS3092DDA THS3092DDAR Power-down THS3096D THS3096DR THS3096PWP THS3096PWPR
ORDERING INFORMATION
PACKAGE TYPE SOIC-8
SOIC-8-PP (1)
100 k
VO = 5 VPP
VO = 2 VPP
1M
10 M
f − Frequency − Hz
100 M
IOUT1 DAC5686
IOUT2
TYPICAL ARBITARY WAVEFORM GENERATOR OUTPUT DRIVE CIRCUIT
− + THS4271
− + THS3092
VOUT
− + THS3092
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
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RECOMMENDED OPERATING CONDITIONS
Supply voltage Operating free-air temperature, TA
Dual supply Single supply

男女谈话的不同英语作文

男女谈话的不同英语作文Differences in Male and Female Conversations。

Communication styles between men and women oftenexhibit intriguing variations that reflect broader social and psychological differences. In this essay, we explore the distinctive characteristics of male and female conversations, examining how these differences influence interpersonal dynamics and relationships.Introduction。

Conversations serve as fundamental tools for human interaction, enabling the exchange of thoughts, emotions, and information. However, studies suggest that men and women engage in conversations differently, driven by unique communication styles and underlying social influences.Male Conversations。

In male conversations, directness and problem-solving often take precedence. Men typically engage in discussions with a focus on achieving concrete outcomes or solutions. This direct approach is rooted in the desire to demonstrate competence and efficiency. Consequently, male conversations tend to revolve around topics like sports, politics, or current affairs, emphasizing factual information and analytical perspectives.Furthermore, male interactions often involve hierarchical positioning and the assertion of authority. Men may use conversations to establish dominance or to compete for status within social or professional settings. This competitive element can sometimes result in debates or arguments, reflecting a desire to assert individual perspectives and opinions.However, despite these characteristics, male conversations can lack emotional depth or vulnerability. Men may hesitate to express feelings openly, preferring instead to maintain a composed or stoic demeanor. Consequently, discussions about personal experiences oremotional concerns may be less common among men.Female Conversations。

Yokogawa DL系列差分探测器（Model 700924）用户手册说明书

User's ManualThank you for purchasing the Differential Probe (Model 700924) for the DL series. To ensure correct use, please read this manual thoroughly before beginning operation. After reading the manual, keep it in a convenient location for quick reference whenever a question arises during operation.IM 700924-01E IM 700924-01EModel 700924Differential Probe for the DL SeriesYOKOGAWA ELECTRIC CORPORATION, Communication & Measurement Business Headquarters Phone: (81)-422-52-67689-32, Nakacho 2-chome, Musashino-shi, Tokyo, 180-8750 JAPANYOKOGAWA CORPORATION OF AMERICA Phone: (1)-770-253-70002 Dart Road, Newnan, Ga. 30265-1094, U.S.A.YOKOGAWA EUROPE B.V. Phone: (31)-33-4641858Databankweg 20, 3821 AL, Amersfoort, THE NETHERLANDS YOKOGAWA ENGINEERING ASIA PTE. LTD. Phone: (65)-624199335 Bedok South Road, Singapore 469270, SINGAPORE7th Edition7th Edition : October 2007 (YK)All Rights Reserved, Copyright © 2007, Yokogawa Electric CorporationSafety PrecautionsMake sure to comply with the safety precautions mentioned hereafter when handling the probe.Yokogawa Electric Corporation assumes no responsibility for any consequences resulting from failure to comply with these safety precautions. Also, read the User’s Manual of the measuring instrument thoroughly so that you are fully aware of its specifications and handling, before starting to use the probe.The following symbols are used on this instrument.Warning: handle with care. Refer to the user’s manual or service manual. This symbol appears on dangerous locations on the instrument which require special instructions forproper handling or use. The same symbol appears in the corresponding place in the manual to identify those instructions. Risk of electric shockMake sure to comply with the following safety precautions in order to prevent accidents such as an electric shock which impose serious health risks to the user and damage to theGrounding of the measuring instrumentThe protective grounding terminal of the measuring instrument must be connected to ground.Earth cable of the probeMake sure to connect the earth cable of the probe to the ground (grounding potential). Do not operated with suspected failuresIf you suspect that there is damage to this probe, have it inspect by a service personnel.Observe maximum working voltageTo avoid any injury,do not use the probe above 1400 Vpeak between each input lead and earth or between the two inputs.This voltage rating applies to both 1/100 and 1/1000 settings.Must be groundedThis probe must be grounded with the BNC shell and an auxiliary grounding terminal, through the grounding conductor of the power cord of the measuring instrument or other appropriate grounding conductor. Before making connections to the input terminals of the product, ensure that the output connector is attached to the BNC connector of the measuring instrument and the auxiliary grounding terminal is connected to a proper ground, while the measuring instrument is properly grounded.Do not operate without coverTo avoid electric shock or fire hazard, do not operate this probe with the cover removed.Do not operate in wet/damp conditionsTo avoid electric shock, do not operate this probe in wet or damp conditions.Do not operate in explosive atmosphereTo aviod injury or fire hazard, do not operate this probe in an explosive atmosphere.Avoid exposed circuitryTo avoid injury, remove jewelry such as rings, watches, and other metallic objects. Do not touch exposed connections and components when power is present.CAUTIONMaximum input voltageDo not apply any voltages exceeding the maximum input voltage to the probe.Correct use of the power supplyPower the probe with either 4 AA dry cells, a 6 VDC/200 mA or 9 VDC/150 mA externalpower supply, or by connecting the probe’s power cable to a probe power supply terminal on a DL series measuring instrument or to the 700938 or 701934. Operating the probe under a power supply greater than the voltage specified above may cause damage to the instrument. Connecting the external power supply to the probeAlways turn OFF the probe’s power switch when connecting or disconnecting the external power supply. Also, do not install the dry cells when using an external power supply.Operating environment limitationsSee below for operating environment limitations.CAUTIONThis product is a Class A (for industrial environments) product. Operation of this product in a residential area may cause radio interference in which case the user is required to correct the interference.Waste Electrical and Electronic Equipment (WEEE), Directive 2002/96/EC (This directive is only valid in the EU.)This product complies with the WEEE Directive (2002/96/EC) marking requirement. This marking indicates that you must not discard this electrical/electronic product in domestic household waste.Product CategoryWith reference to the equipment types in the WEEE directive Annex 1, this product is classified as a “Monitoring and Control instrumentation” product.Do not dispose in domestic household waste. When disposing products in the EU, contact your local Yokogawa Europe B. V. office.The Following Symbols are Used in this Manual.Improper handling or use can lead to injury to the user or damage to the instrument. This symbol appears on the instrument to indicate that the user must refer to theuser’s manual for special instructions. The same symbol appears in the corresponding place in the user’s manual to identify those instructions. In the manual, the symbol is used in conjunction with the word “WARNING” or “CAUTION.”WARNING Calls attention to actions or conditions that could cause serious or fatal injury to theuser, and precautions that can be taken to prevent such occurrences.CAUTION Calls attentions to actions or conditions that could cause light injury to the user ordamage to the instrument or user’s data, and precautions that can be taken to prevent such occurrences.NoteCalls attention to information that is important for proper operation of the instrument.1 DescriptionBy using this device, oscilloscopes with single-ended input can be easily used as oscilloscopes with differential inputs.2 Appearance22 Pinchers tips3 Ground extention lead (length = 100 cm)Power cable*Pinchers tip B9852MJ Black: B9852MM, Red: B9852MN* Power can be supplied from the DL, 700938,or 701934.Optional Accessories (Sold Separately)3 Installing/Replacing the Dry CellsShift the lid at the back side of the probe and install/replace the four dry cells. The dry cells are not installed on receipt of the instrument.4 Operation1. Install four AA cells. When using an external power supply, do not install the dry cells. Supply power only through the external power supply.2. Simply plug-in the BNC output connector to the vertical input of a oscilloscope, and connect the auxiliary grounding terminal to a proper ground. If necessary, use a ground extention lead.3. Select the proper range setting. For higher resolution and less noise when measuring signals below 350V, switch the attenuation to 1/100. Otherwise, set the attenuation to 1/1000 when measuring signals above 350V.4. If the offset voltage is large, short the top of input leads, and turn the ADJUST variable resistor (DC voltage adjustment) using a flat-head screwdriver to adjust the offset voltage.• To protect against electric shock the ground side of the output cable (the shielded side of the BNC connector) must be grounded.• Make sure to avoid an electric shock when connecting the probe to the object ofmeasurement. Do not remove the probe from the measuring instrument after the object of measurement is connected.• When disconnecting the probe BNC output connector, first turn OFF the power to the circuit under measurement. Then, disconnect the probe from the high voltage parts of the circuit under measurement.• When replacing batteries or connecting an external power supply, first turn OFF the power to the circuit under measurement. Then, remove the input lead from the circuit under measurement.CAUTION• This probe is to carry out differential measurement between two points on the circuit under measurement. This probe is not for electrically insulating the circuit under measurement and the measuring instrument.• Use a soft cloth to clean the dirt. Prevent damage to the probe. Avoid immersing the probe, using abrasive cleaners, and using chemicals contains benzene or similar solvents.Note• Connect the BNC connector to the input terminal of the oscilloscope and for two pointmeasurement (differential measurement), connect both input leads. Because the performance declines in case you carry out measurements with only one input lead connected, make sure to always connect both.• Accurate measurement may not be possible near objects with strong electric fields (such as cordless equipment, transformers, or circuits with large currents).5 SpecificationsItemSpecificationsFrequency bandwidth *1DC to 100 MHz (−3 dB)Input typeBalancing difference inputAttenuation ratioswitched ratios of 100:1 and 1000:1Output offset voltage *1 *2±7.5 mVInput resistance and capacity 4 M Ω + 10 pF each side to groundDifferential allowable voltage ±1400 V (DC + ACpeak) or 1000 Vrms at 1000:1 attenuation (between + − terminal)±350 V (DC + ACpeak) or 250 Vrms at 100:1 attenuation Max common mode voltage ±1400 V (DC + ACpeak) or 1000 Vrms Max input voltage(to ground)±1400 V (DC + ACpeak) or 1000 VrmsCMRR (typical)*160 Hz: less than −80 dB; 1 MHz: less than −50 dB Output voltage *1±3.5 V (DC + ACpeak)Output impedance Using 1 M Ω input system oscilloscopeGain accuracy *1±2% (common mode voltage ≤ 400 V and ≥ −400 V)±3% (common mode voltage ≤ 1000 V and ≥ −1000 V)Operating environment 5 to 40°C, 25 to 85% (no condensation)Storage environment −30 to 60°C, 25 to 85% (no condensation)Operating altitude 2,000 m or lessPower requirements *3Internal battery: four dry cells (AA, R6)External power supply:6 VDC/200 mA or more, or 9 VDC/150 mA or more.From the DL series instrument’s probe power supply, 700938, or 701934 using the probe’s power supply cable. Cell life time In continuous duty, approx. 2 hoursDimensions 207 mm × 83 mm × 38 mm (excluding connector and cable)WeightApprox. 800 g ( excluding the dry cells)Withstanding voltage 2000 VACrms (between input terminal and BNC-ground), for 5 minutesSafety standardsComplying standards EN61010-031Measurement category III *4: 1400 V (DC + ACpeak)Pollution degree 2*5EmissionComplying standardsEN61326, EN55011, EN61000-3-2, EN61000-3-3This product is a Class A (for industrial environment) product. Operation of this product in a residential area may cause radio interference in which case the user is required to correct the interference.ImmunityComplying standards EN61326*1 When the power supply voltage from the dry cells is 5 V or more, or when using an external power supply.*2 Ambient temperature 23±5°C*3 When the capacity of dry cells goes down LED blinks. In such a case, replace the dry cells. Also, do not install the dry cells when using an external power supply.*4This equipment is for measurement category III (CAT III). Do not use it with measurement category IV (CAT IV). CAT III applies to measurement of the distribution level, that is , building wiring, fixed installations. CAT IV applies to measurement of the primary supply level, that is, overhead lines, cable systems, and so on.*5 Pollution degree applies to the degree of adhesion of a solid, liquid, or gas which deteriorates withstandvoltage or surface resistivity. Pollution degree 2 applies to normal indoor atmospheres (with only non-conductive pollution).Input voltage deratingFrequency (Hz)0.1 M1010010001400 1 M 10 M 100 M M a x i n p u t v o l t a g e (V )1981。

Development and Applications of CRISPR-Cas9 for Genome Engineering

Leading EdgeReviewDevelopment and Applications ofCRISPR-Cas9for Genome EngineeringPatrick D.Hsu,1,2,3Eric nder,1and Feng Zhang1,2,*1Broad Institute of MIT and Harvard,7Cambridge Center,Cambridge,MA02141,USA2McGovern Institute for Brain Research,Department of Brain and Cognitive Sciences,Department of Biological Engineering, Massachusetts Institute of Technology,Cambridge,MA02139,USA3Department of Molecular and Cellular Biology,Harvard University,Cambridge,MA02138,USA*Correspondence:zhang@/10.1016/j.cell.2014.05.010Recent advances in genome engineering technologies based on the CRISPR-associated RNA-guided endonuclease Cas9are enabling the systematic interrogation of mammalian genome function.Analogous to the search function in modern word processors,Cas9can be guided to speciﬁc locations within complex genomes by a short RNA search ing this system, DNA sequences within the endogenous genome and their functional outputs are now easily edited or modulated in virtually any organism of choice.Cas9-mediated genetic perturbation is simple and scalable,empowering researchers to elucidate the functional organization of the genome at the systems level and establish causal linkages between genetic variations and biological phenotypes. In this Review,we describe the development and applications of Cas9for a variety of research or translational applications while highlighting challenges as well as future directions.Derived from a remarkable microbial defense system,Cas9is driving innovative applications from basic biology to biotechnology and medicine.IntroductionThe development of recombinant DNA technology in the1970s marked the beginning of a new era for biology.For theﬁrst time,molecular biologists gained the ability to manipulate DNA molecules,making it possible to study genes and harness them to develop novel medicine and biotechnology.Recent advances in genome engineering technologies are sparking a new revolution in biological research.Rather than studying DNA taken out of the context of the genome,researchers can now directly edit or modulate the function of DNA sequences in their endogenous context in virtually any organism of choice, enabling them to elucidate the functional organization of the genome at the systems level,as well as identify causal genetic variations.Broadly speaking,genome engineering refers to the process of making targeted modiﬁcations to the genome,its contexts (e.g.,epigenetic marks),or its outputs(e.g.,transcripts).The ability to do so easily and efﬁciently in eukaryotic and especially mammalian cells holds immense promise to transform basic sci-ence,biotechnology,and medicine(Figure1).For life sciences research,technologies that can delete,insert, and modify the DNA sequences of cells or organisms enable dis-secting the function of speciﬁc genes and regulatory elements. Multiplexed editing could further allow the interrogation of gene or protein networks at a larger scale.Similarly,manipu-lating transcriptional regulation or chromatin states at particular loci can reveal how genetic material is organized and utilized within a cell,illuminating relationships between the architecture of the genome and its functions.In biotechnology,precise manipulation of genetic building blocks and regulatory machin-ery also facilitates the reverse engineering or reconstruction of useful biological systems,for example,by enhancing biofuel production pathways in industrially relevant organisms or by creating infection-resistant crops.Additionally,genome engi-neering is stimulating a new generation of drug development processes and medical therapeutics.Perturbation of multiple genes simultaneously could model the additive effects that un-derlie complex polygenic disorders,leading to new drug targets, while genome editing could directly correct harmful mutations in the context of human gene therapy(Tebas et al.,2014). Eukaryotic genomes contain billions of DNA bases and are difﬁcult to manipulate.One of the breakthroughs in genome manipulation has been the development of gene targeting by homologous recombination(HR),which integrates exogenous repair templates that contain sequence homology to the donor site(Figure2A)(Capecchi,1989).HR-mediated targeting has facilitated the generation of knockin and knockout animal models via manipulation of germline competent stem cells, dramatically advancing many areas of biological research.How-ever,although HR-mediated gene targeting produces highly pre-cise alterations,the desired recombination events occur extremely infrequently(1in106–109cells)(Capecchi,1989),pre-senting enormous challenges for large-scale applications of gene-targeting experiments.To overcome these challenges,a series of programmable nuclease-based genome editing technologies havebeen1262Cell157,June5,2014ª2014Elsevier Inc.developed in recent years,enabling targeted and efﬁcient modi-ﬁcation of a variety of eukaryotic and particularly mammalian species.Of the current generation of genome editing technolo-gies,the most rapidly developing is the class of RNA-guided endonucleases known as Cas9from the microbial adaptive im-mune system CRISPR (clustered regularly interspaced short palindromic repeats),which can be easily targeted to virtually any genomic location of choice by a short RNA guide.Here,we review the development and applications of the CRISPR-associated endonuclease Cas9as a platform technology for achieving targeted perturbation of endogenous genomic ele-ments and also discuss challenges and future avenues for inno-vation.Programmable Nucleases as Tools for Efﬁcient and Precise Genome EditingA series of studies by Haber and Jasin (Rudin et al.,1989;Plessis et al.,1992;Rouet et al.,1994;Choulika et al.,1995;Bibikova et al.,2001;Bibikova et al.,2003)led to the realization that tar-geted DNA double-strand breaks (DSBs)could greatly stimulate genome editing through HR-mediated recombination events.Subsequently,Carroll and Chandrasegaran demonstrated the potential of designer nucleases based on zinc ﬁnger proteins for efﬁcient,locus-speciﬁc HR (Bibikova et al.,2001,2003).Moreover,it was shown in the absence of an exogenous homol-ogy repair template that localized DSBs can induce insertions or deletion mutations (indels)via the error-prone nonhomologous end-joining (NHEJ)repair pathway (Figure 2A)(Bibikova et al.,2002).These early genome editing studies established DSB-induced HR and NHEJ as powerful pathways for the versatileand precise modiﬁcation of eukaryotic genomes.To achieve effective genome editing via introduction of site-speciﬁc DNA DSBs,four major classes of customizable DNA-binding proteins have been engineered so far:meganucleases derived from microbial mobile genetic elements (Smith et al.,2006),zinc ﬁnger (ZF)nucleases based on eukaryotic transcrip-tion factors (Urnov et al.,2005;Miller et al.,2007),transcription activator-like effectors (TALEs)from Xanthomonas bacteria (Christian et al.,2010;Miller et al.,2011;Boch et al.,2009;Mos-cou and Bogdanove,2009),and most recently the RNA-guided DNA endonuclease Cas9from the type II bacterial adaptive im-mune system CRISPR (Cong et al.,2013;Mali et al.,2013a ).Meganuclease,ZF,and TALE proteins all recognize speciﬁc DNA sequences through protein-DNA interactions.Although meganucleases integrate its nuclease and DNA-binding domains,ZF and TALE proteins consist of individual modules targeting 3or 1nucleotides (nt)of DNA,respectively (Figure 2B).ZFs and TALEs can be assembled in desired combi-nations and attached to the nuclease domain of FokI to direct nucleolytic activity toward speciﬁc genomic loci.Each of these platforms,however,has unique limitations.Meganucleases have not been widely adopted as a genome engineering platform due to lack of clear correspondence between meganuclease protein residues and their target DNA sequence speciﬁcity.ZF domains,on the other hand,exhibit context-dependent binding preference due to crosstalk between adjacent modules when assembled into a larger array (Maeder et al.,2008).Although multiple strategies have been developed to account for these limitations (Gonzaelz et al.,2010;Sander et al.,2011),assembly of functional ZFPs with the desired DNA binding speciﬁcity remains a major challenge that requires an extensive screening process.Similarly,although TALE DNA-binding monomers are for the most part modular,they can still suffer from context-dependent speciﬁcity (Juillerat et al.,2014),and their repetitive sequences render construction of novel TALE arrays labor intensive and costly.Given the challenges associated with engineering of modular DNA-binding proteins,new modes of recognition would signiﬁ-cantly simplify the development of custom nucleases.The CRISPR nuclease Cas9is targeted by a short guide RNA that recognizes the target DNA via Watson-Crick base pairing (Figure 2C).The guide sequence within these CRISPR RNAs typically corresponds to phage sequences,constituting the nat-ural mechanism for CRISPR antiviral defense,but can be easily replaced by a sequence of interest to retarget the Cas9nuclease.Multiplexed targeting by Cas9can now be achieved at unprecedented scale by introducing a battery of short guideFigure 1.Applications of Genome EngineeringGenetic and epigenetic control of cells with genome engineering technologies is enabling a broad range of applications from basic biology to biotechnology and medicine.(Clockwise from top)Causal genetic mutations or epigenetic variants associated with altered biological function or disease phenotypes can now be rapidly and efﬁciently recapitulated in animal or cellular models (Animal models,Genetic variation).Manipulating biological circuits could also facilitate the generation of useful synthetic materials,such as algae-derived,silica-based diatoms for oral drug delivery (Materials).Additionally,precise genetic engineering of important agricultural crops could confer resistance to envi-ronmental deprivation or pathogenic infection,improving food security while avoiding the introduction of foreign DNA (Food).Sustainable and cost-effec-tive biofuels are attractive sources for renewable energy,which could be achieved by creating efﬁcient metabolic pathways for ethanol production in algae or corn (Fuel).Direct in vivo correction of genetic or epigenetic defects in somatic tissue would be permanent genetic solutions that address the root cause of genetically encoded disorders (Gene surgery).Finally,engineering cells to optimize high yield generation of drug precursors in bacterial factories could signiﬁcantly reduce the cost and accessibility of useful therapeutics (Drug development).Cell 157,June 5,2014ª2014Elsevier Inc.1263RNAs rather than a library of large,bulky proteins.The ease of Cas9targeting,its high efﬁciency as a site-speciﬁc nuclease,and the possibility for highly multiplexed modiﬁcations have opened up a broad range of biological applications across basic research to biotechnology and medicine.The utility of customizable DNA-binding domains extends far beyond genome editing with site-speciﬁc endonucleases.Fusing them to modular,sequence-agnostic functional effector domains allows ﬂexible recruitment of desired perturbations,such as transcriptional activation,to a locus of interest (Xu and Bestor,1997;Beerli et al.,2000a;Konermann et al.,2013;Maeder et al.,2013a;Mendenhall et al.,2013).In fact,any modular enzymatic component can,in principle,be substituted,allowing facile additions to the genome engineering toolbox.Integration of genome-and epigenome-modifying enzymes with inducible protein regulation further allows precise temporal control of dynamic processes (Beerli et al.,2000b;Konermann et al.,2013).CRISPR-Cas9:From Yogurt to Genome EditingThe recent development of the Cas9endonuclease for genome editing draws upon more than a decade of basic research into understanding the biological function of the mysterious repetitive elements now known as CRISPR (Figure 3),which are found throughout the bacterial and archaeal diversity.CRISPR loci typically consist of a clustered set of CRISPR-associated (Cas)genes and the signature CRISPR array—a series of repeat sequences (direct repeats)interspaced by variable sequences (spacers)corresponding to sequences within foreign genetic elements (protospacers)(Figure 4).Whereas Cas genes are translated into proteins,most CRISPR arrays are ﬁrst tran-scribed as a single RNA before subsequent processing into shorter CRISPR RNAs (crRNAs),which direct the nucleolytic activity of certain Cas enzymes to degrade target nucleic acids.The CRISPR story began in 1987.While studying the iap enzyme involved in isozyme conversion of alkaline phosphatase in E.coli ,Nakata and colleagues reported a curious set of 29nt repeats downstream of the iap gene (Ishino et al.,1987).Unlike most repetitive elements,which typically take the form of tandem repeats like TALE repeat monomers,these 29nt repeats were interspaced by ﬁve intervening 32nt nonrepetitive sequences.Over the next 10years,as more microbial genomes were sequenced,additional repeat elements were reported from genomes of different bacterial and archaeal strains.Mojica and colleagues eventually classiﬁed interspaced repeat sequences as a unique family of clustered repeat elements present in >40%of sequenced bacteria and 90%of archaea (Mojica et al.,2000).These early ﬁndings began to stimulate interest in such micro-bial repeat elements.By 2002,Jansen and Mojica coined the acronym CRISPR to unify the description of microbial genomic loci consisting of an interspaced repeat array (Jansen et al.,2002;Barrangou and van der Oost,2013).At the same time,several clusters of signature CRISPR-associated (cas )genes were identiﬁed to be well conserved and typically adjacent to the repeat elements (Jansen et al.,2002),serving as a basis for the eventual classiﬁcation of three different types of CRISPR systems (types I–III)(Haft et al.,2005;Makarova et al.,2011b ).Types I and III CRISPR loci contain multiple Cas proteins,now known to form complexes with crRNA (CASCADE complex for type I;Cmr or Csm RAMP complexes for type III)to facilitate the recognition and destruction of target nucleic acids (BrounsFigure 2.Genome Editing Technologies Exploit Endogenous DNA Repair Machinery(A)DNA double-strand breaks (DSBs)are typically repaired by nonhomologous end-joining (NHEJ)or homology-directed repair (HDR).In the error-prone NHEJ pathway,Ku heterodimers bind to DSB ends and serve as a molecular scaffold for associated repair proteins.Indels are introduced when the complementary strands undergo end resection and misaligned repair due to micro-homology,eventually leading to frameshift muta-tions and gene knockout.Alternatively,Rad51proteins may bind DSB ends during the initial phase of HDR,recruiting accessory factors that direct genomic recombination with homology arms on an exogenous repair template.Bypassing the matching sister chromatid facilitates the introduction of precise gene modiﬁcations.(B)Zinc ﬁnger (ZF)proteins and transcription activator-like effectors (TALEs)are naturally occurring DNA-binding domains that can be modularly assembled to target speciﬁc se-quences.ZF and TALE domains each recognize 3and 1bp of DNA,respectively.Such DNA-binding proteins can be fused to the FokI endonuclease to generate programmable site-speciﬁc nucleases.(C)The Cas9nuclease from the microbial CRISPR adaptive immune system is localized to speciﬁc DNA sequences via the guide sequence on its guide RNA (red),directly base-pairing with the DNA target.Binding of a protospacer-adjacent motif (PAM,blue)downstream of the target locus helps to direct Cas9-mediated DSBs.1264Cell 157,June 5,2014ª2014Elsevier Inc.et al.,2008;Hale et al.,2009)(Figure 4).In contrast,the type II system has a signiﬁcantly reduced number of Cas proteins.However,despite increasingly detailed mapping and annotation of CRISPR loci across many microbial species,their biological signiﬁcance remained elusive.A key turning point came in 2005,when systematic analysis of the spacer sequences separating the individual direct repeats suggested their extrachromosomal and phage-associated ori-gins (Mojica et al.,2005;Pourcel et al.,2005;Bolotin et al.,2005).This insight was tremendously exciting,especially given previous studies showing that CRISPR loci are transcribed (Tang et al.,2002)and that viruses are unable to infect archaeal cells carrying spacers corresponding to their own genomes (Mojica et al.,2005).Together,these ﬁndings led to the specula-tion that CRISPR arrays serve as an immune memory and defense mechanism,and individual spacers facilitate defense against bacteriophage infection by exploiting Watson-Crick base-pairing between nucleic acids (Mojica et al.,2005;Pourcel et al.,2005).Despite these compelling realizations that CRISPR loci might be involved in microbial immunity,the speciﬁc mech-anism of how the spacers act to mediate viral defense remained a challenging puzzle.Several hypotheses were raised,including thoughts that CRISPR spacers act as small RNA guides to degrade viral transcripts in a RNAi-like mechanism (Makarova et al.,2006)or that CRISPR spacers direct Cas enzymes to cleave viral DNA at spacer-matching regions (Bolotin et al.,2005).Working with the dairy production bacterial strain Strepto-coccus thermophilus at the food ingredient company Danisco,Horvath and colleagues uncovered the ﬁrst experimental evidence for the natural role of a type II CRISPR system as an adaptive immunity system,demonstrating a nucleic-acid-based immune system in which CRISPR spacers dictate target speci-ﬁcity while Cas enzymes control spacer acquisition and phage defense (Barrangou et al.,2007).A rapid series of studies illumi-nating the mechanisms of CRISPR defense followed shortly and helped to establish the mechanism as well as function of all three types of CRISPR loci in adaptive immunity.By studying the type I CRISPR locus of Escherichia coli ,van der Oost and colleagues showed that CRISPR arrays are transcribed and converted into small crRNAs containing individual spacers to guide Cas nuclease activity (Brouns et al.,2008).In the same year,CRISPR-mediated defense by a type III-A CRISPR system from Staphylococcus epidermidis was demonstrated to block plasmid conjugation,establishing the target of Cas enzyme activity as DNA rather than RNA (Marrafﬁni andSontheimer,Figure 3.Key Studies Characterizing and Engineering CRISPR SystemsCas9has also been referred to as Cas5,Csx12,and Csn1in literature prior to 2012.For clarity,we exclusively adopt the Cas9nomenclature throughout this Review.CRISPR,clustered regularly interspaced short palindromic repeats;Cas,CRISPR-associated;crRNA,CRISPR RNA;DSB,double-strand break;tracrRNA,trans -activating CRISPR RNA.Cell 157,June 5,2014ª2014Elsevier Inc.12652008),although later investigation of a different type III-B system from Pyrococcus furiosus also revealed crRNA-directed RNA cleavage activity(Hale et al.,2009,2012).As the pace of CRISPR research accelerated,researchers quickly unraveled many details of each type of CRISPR system (Figure4).Building on an earlier speculation that protospacer-adjacent motifs(PAMs)may direct the type II Cas9nuclease to cleave DNA(Bolotin et al.,2005),Moineau and colleagues high-lighted the importance of PAM sequences by demonstrating that PAM mutations in phage genomes circumvented CRISPR inter-ference(Deveau et al.,2008).Additionally,for types I and II,the lack of PAM within the direct repeat sequence within the CRISPR array prevents self-targeting by the CRISPR system.In type III systems,however,mismatches between the50end of the crRNA and the DNA target are required for plasmid interference(Marraf-ﬁni and Sontheimer,2010).By2010,just3years after theﬁrst experimental evidence for CRISPR in bacterial immunity,the basic function and mecha-nisms of CRISPR systems were becoming clear.A variety of groups had begun to harness the natural CRISPR system for various biotechnological applications,including the generation of phage-resistant dairy cultures(Quiberoni et al.,2010)and phylogenetic classiﬁcation of bacterial strains(Horvath et al., 2008,2009).However,genome editing applications had not yet been explored.Around this time,two studies characterizing the functional mechanisms of the native type II CRISPR system elucidated the basic components that proved vital for engineering a simple RNA-programmable DNA endonuclease for genome editing. First,Moineau and colleagues used genetic studies in Strepto-coccus thermophilus to reveal that Cas9(formerly called Cas5,Csn1,or Csx12)is the only enzyme within the cas gene cluster that mediates target DNA cleavage(Garneau et al.,2010).Next,Charpentier and colleagues revealed a key component in the biogenesis and processing of crRNA in type II CRISPR systems—a noncoding trans-activating crRNA(tracrRNA)that hybridizes with crRNA to facilitate RNA-guided targeting of Cas9(Deltcheva et al.,2011).This dual RNA hybrid,together with Cas9and endogenous RNase III,is required for processing the CRISPR array transcript into mature crRNAs(Deltcheva et al.,2011).These two studies suggested that there are at least three components(Cas9, the mature crRNA,and tracrRNA)that are essential for recon-stituting the type II CRISPR nuclease system.Given the increasing importance of programmable site-speciﬁc nucleases based on ZFs and TALEs for enhancing eukaryotic genome editing,it was tantalizing to think that perhaps Cas9could be developed into an RNA-guided genome editing system. From this point,the race to harness Cas9for genome editing wason.Figure4.Natural Mechanisms of Microbial CRISPR Systems in Adaptive Immunity Following invasion of the cell by foreign genetic elements from bacteriophages or plasmids(step 1:phage infection),certain CRISPR-associated (Cas)enzymes acquire spacers from the exoge-nous protospacer sequences and install them into the CRISPR locus within the prokaryotic genome (step2:spacer acquisition).These spacers are segregated between direct repeats that allow the CRISPR system to mediate self and nonself recognition.The CRISPR array is a noncoding RNA transcript that is enzymatically maturated through distinct pathways that are unique to each type of CRISPR system(step3:crRNA biogenesis and processing).In types I and III CRISPR,the pre-crRNA transcript is cleaved within the repeats by CRISPR-asso-ciated ribonucleases,releasing multiple small crRNAs.Type III crRNA intermediates are further processed at the30end by yet-to-be-identiﬁed RNases to produce the fully mature transcript.In type II CRISPR,an associated trans-activating CRISPR RNA(tracrRNA)hybridizes with the direct repeats,forming an RNA duplex that is cleaved and processed by endogenous RNase III and other unknown nucleases.Maturated crRNAs from type I and III CRISPR systems are then loaded onto effector protein complexes for target recognition and degradation.In type II systems, crRNA-tracrRNA hybrids complex with Cas9to mediate interference.Both type I and III CRISPR systems use multi-protein interference modules to facilitate target recognition.In type I CRISPR,the Cascade com-plex is loaded with a crRNA molecule,constituting a catalytically inert surveillance complex that rec-ognizes target DNA.The Cas3nuclease is then recruited to the Cascade-bound R loop,mediatingtarget degradation.In type III CRISPR,crRNAs associate either with Csm or Cmr complexes that bind and cleave DNA and RNA substrates,respectively.In contrast,the type II system requires only the Cas9nuclease to degrade DNA matching its dual guide RNA consisting of a crRNA-tracrRNA hybrid.1266Cell157,June5,2014ª2014Elsevier Inc.In2011,Siksnys and colleaguesﬁrst demonstrated that the type II CRISPR system is transferrable,in that transplantation of the type II CRISPR locus from Streptococcus thermophilus into Escherichia coli is able to reconstitute CRISPR interference in a different bacterial strain(Sapranauskas et al.,2011).By 2012,biochemical characterizations by the groups of Charpent-ier,Doudna,and Siksnys showed that puriﬁed Cas9from Strep-tococcus thermophilus or Streptococcus pyogenes can be guided by crRNAs to cleave target DNA in vitro(Jinek et al., 2012;Gasiunas et al.,2012),in agreement with previous bacte-rial studies(Garneau et al.,2010;Deltcheva et al.,2011;Sapra-nauskas et al.,2011).Furthermore,a single guide RNA(sgRNA) can be constructed by fusing a crRNA containing the targeting guide sequence to a tracrRNA that facilitates DNA cleavage by Cas9in vitro(Jinek et al.,2012).In2013,a pair of studies simultaneously showed how to suc-cessfully engineer type II CRISPR systems from Streptococcus thermophilus(Cong et al.,2013)and Streptococcus pyogenes (Cong et al.,2013;Mali et al.,2013a)to accomplish genome editing in mammalian cells.Heterologous expression of mature crRNA-tracrRNA hybrids(Cong et al.,2013)as well as sgRNAs (Cong et al.,2013;Mali et al.,2013a)directs Cas9cleavage within the mammalian cellular genome to stimulate NHEJ or HDR-mediated genome editing.Multiple guide RNAs can also be used to target several genes at once.Since these initial studies,Cas9has been used by thousands of laboratories for genome editing applications in a variety of experimental model systems(Sander and Joung,2014).The rapid adoption of the Cas9technology was also greatly accelerated through a com-bination of open-source distributors such as Addgene,as well as a number of online user forums such as http://www. and . Structural Organization and Domain Architecture ofCas9The family of Cas9proteins is characterized by two signature nuclease domains,RuvC and HNH,each named based on homology to known nuclease domain structures(Figure2C). Though HNH is a single nuclease domain,the full RuvC domain is divided into three subdomains across the linear protein sequence,with RuvC I near the N-terminal region of Cas9and RuvC II/IIIﬂanking the HNH domain near the middle of the pro-tein.Recently,a pair of structural studies shed light on the struc-tural mechanism of RNA-guided DNA cleavage by Cas9. First,single-particle EM reconstructions of the Streptococcus pyogenes Cas9(SpCas9)revealed a large structural rearrange-ment between apo-Cas9unbound to nucleic acid and Cas9in complex with crRNA and tracrRNA,forming a central channel to accommodate the RNA-DNA heteroduplex(Jinek et al., 2014).Second,a high-resolution structure of SpCas9in complex with sgRNA and the complementary strand of target DNA further revealed the domain organization to comprise of an a-helical recognition(REC)lobe and a nuclease(NUC)lobe consisting of the HNH domain,assembled RuvC subdomains,and a PAM-interacting(PI)C-terminal region(Nishimasu et al.,2014) (Figure5A and Movie S1).Together,these two studies support the model that SpCas9 unbound to target DNA or guide RNA exhibits an autoinhibited conformation in which the HNH domain active site is blocked by the RuvC domain and is positioned away from the REC lobe (Jinek et al.,2014).Binding of the RNA-DNA heteroduplex would additionally be sterically inhibited by the orientation of the C-ter-minal domain.As a result,apo-Cas9likely cannot bind nor cleave target DNA.Like many ribonucleoprotein complexes,the guide RNA serves as a scaffold around which Cas9can fold and orga-nize its various domains(Nishimasu et al.,2014).The crystal structure of SpCas9in complex with an sgRNA and target DNA also revealed how the REC lobe facilitates target binding.An arginine-rich bridge helix(BH)within the REC lobe is responsible for contacting the308–12nt of the RNA-DNA het-eroduplex(Nishimasu et al.,2014),which correspond with the seed sequence identiﬁed through guide sequence mutation ex-periments(Jinek et al.,2012;Cong et al.,2013;Fu et al.,2013; Hsu et al.,2013;Pattanayak et al.,2013;Mali et al.,2013b). The SpCas9structure also provides a useful scaffold for engi-neering or refactoring of Cas9and sgRNA.Because the REC2 domain of SpCas9is poorly conserved in shorter orthologs, domain recombination or truncation is a promising approach for minimizing Cas9size.SpCas9mutants lacking REC2retain roughly50%of wild-type cleavage activity,which could be partly attributed to their weaker expression levels(Nishimasu et al., 2014).Introducing combinations of orthologous domain re-combination,truncation,and peptide linkers could facilitate the generation of a suite of Cas9mutant variants optimized for different parameters such as DNA binding,DNA cleavage,or overall protein size.Metagenomic,Structural,and Functional Diversity of Cas9Cas9is exclusively associated with the type II CRISPR locus and serves as the signature type II gene.Based on the diversity of associated Cas genes,type II CRISPR loci are further subdivided into three subtypes(IIA–IIC)(Figure5B)(Makarova et al.,2011a; Chylinski et al.,2013).Type II CRISPR loci mostly consist of the cas9,cas1,and cas2genes,as well as a CRISPR array and tracrRNA.Type IIC CRISPR systems contain only this minimal set of cas genes,whereas types IIA and IIB have an additional signature csn2or cas4gene,respectively(Chylinski et al.,2013). Subtype classiﬁcation of type II CRISPR loci is based on the architecture and organization of each CRISPR locus.For example,type IIA and IIB loci usually consist of four cas genes, whereas type IIC loci only contain three cas genes.However, this classiﬁcation does not reﬂect the structural diversity of Cas9proteins,which exhibit sequence homology and length variability irrespective of the subtype classiﬁcation of their parental CRISPR locus.Of>1,000Cas9nucleases identiﬁed from sequence databases(UniProt)based on homology,protein length is rather heterogeneous,roughly ranging from900to1600 amino acids(Figure5C).The length distribution of most Cas9 proteins can be divided into two populations centered around 1,100and1,350amino acids in length.It is worth noting that a third population of large Cas9proteins belonging to subtype IIA,formerly called Csx12,typically contain around1500amino acids.Despite the apparent diversity of protein length,all Cas9pro-teins share similar domain architecture(Makarova et al.,2011a;Cell157,June5,2014ª2014Elsevier Inc.1267。

SmartLine STT850智能温度传感器说明书

SmartLineTechnical InformationSTT850 SmartLine Temperature Transmitter Specification 34-TT-03-14, August 2023IntroductionPart of the SmartLine® family of products, the SmartLine STT850 is a high-performance temperature transmitter offering high accuracy and stability over a wide range of process and ambient temperatures. The SmartLine family is also fully tested and compliant with Experion ® PKS providing the highest level of compatibility assurance and integration capabilities. SmartLine easily meets the most demanding needs for temperature measurement applications.Best in Class Features:Industry-leading performanceo Digital Accuracy up to +/- 0.10 Deg C for RTD. oStability up to +/- 0.01% of URL per year for ten years. o 125 mSec update time for single input models. o250 mSec update time for dual input models.Reliable measuremento Built in Galvanic Isolation.oDifferential / Averaging / Redundant / Split Range measurements. o Dual Compartment Housing. o Sensor Break detection.o Comprehensive on-board diagnostic capabilities. o Full compliance to SIL 2/3 requirements. o Available with 15-year warranty.o Supports Namur 107 Extended Diagnostics (FF). o Supports Namur 89 Wire break.oDirect entry of Callendar-Van Dusen coefficients R 0, α, δ and β for calibrated RTD sensors (not available on DE units).Figure 1– Smartline STT850 TemperaturetransmitterLower Cost of Ownershipo Universal input o Dual sensor optiono Multiple local display capabilities o Modular constructiono External zero, span, & configuration capability o Polarity insensitive loop wiringoDigital Output Option (only available with HART)Communications/Output Options:o 4-20 mA dco Honeywell Digitally Enhanced (DE) o HART ® (version 7.0)oF OUNDATION™ Fieldbu s compliant to ITK 6.1.2All transmitters are available with the above listed communications protocols.DescriptionThe SmartLine Temperature Transmitter is designed and manufactured to deliver very high performance across varying ambient temperature. The total accuracy of the transmitter including the ambient temperature effect in harsh industrial environments, allows the STT850 to replace virtually any competitive transmitter available today.Unique Indication/Display OptionsThe STT850 modular design accommodates a basic alphanumeric LCD display or a unique advanced graphics LCD display with many unparalleled features.Standard LCD Display Featureso Modular (may be added or removed in the field).o0, 90,180, & 270-degree position adjustments.o Deg C, F, R, Kelvin, Milli volts, and Ohm measurement units.o 2 Lines 6 digits PV (9.95H x 4.20W mm), 8 Characters. o Device configuration and calibration through integral buttons or optional external buttons.o Up to 4 configurable display screens.o Configurable screen rotation timing (2 to 20 sec).o Write protect indication.o Critical fault indication.Advanced Graphics LCD Display Featureso Modular (may be added or removed in the field)o0, 90, 180, & 270-degree position adjustmentso Up to eight display screens with 3 formats are possible o Large PV (HART), PV with Bar Graph or PV with Trend Graph.o Configurable screen rotation timing (3 to 30 sec)o Provides instant visibility for diagnosticso Multiple language capability. (EN, GE, FR, IT, SP, RU, TR, CN & JP)Configuration ToolsIntegral Three Button Configuration OptionSuitable for all electrical and environmental requirements, SmartLine offers the ability to configure the transmitter and display via three externally accessible buttons when display option is selected. Zero or span capabilities are also optionally available via these buttons with or without the selection of a display option. Handheld ConfigurationSmartLine transmitters feature two-way communication and configuration capability between the operator and the transmitter. This is accomplished via Honeywell Versatilis, field-rated, next generation multiple communication configuration tool.The Honeywell Versatilis Handheld is capable of field configuring DE and HART Devices and can also be ordered for use in intrinsically safe environments.All Honeywell transmitters are designed and tested for compliance with the offered communication protocols and are designed to operate with any properly validated handheld configuration device.Personal Computer ConfigurationHoneywell’s SCT 3000 Configuration Toolkit provides an easy way to configure Digitally Enhanced (DE) instruments using a personal computer as the configuration interface.Field Device Manager (FDM) Software and FDM Express are also available for managing HART, DE & Fieldbus device configurations.DiagnosticsSmartLine transmitters all offer digitally accessible diagnostics which aid in providing advanced warning of possible failure events minimizing unplanned shutdowns, providing lower overall operational costsSystem Integrationo SmartLine communications protocols all meet the most current published standards for HART/DE/Fieldbus.o Integration with Honeywel l’s Exper ion PKS offers the following unique advantages.•Transmitter messaging•Maintenance mode indication•Tamper reporting (HART only)•FDM Plant Area Views with Health summaries•All STT850 units are Experion tested to provide the highest level of compatibility assuranceModular DesignTo help contain maintenance & inventory costs, all STT850 transmitters are modular in design supporting the user’s ability to replace temperature boards, add indicators or change electronic modules without affecting overall performance or approval body certifications. Each temperature board is uniquely characterized to provide in-tolerance performance over a wide rangeof application variations in temperature and due to the Honeywell advanced interface, electronic modules may be swapped with any electronics module without losing in-tolerance performance characteristics.Modular Featureso Replace Temperature/Terminal board/Lightning protection*o Exchange/replace electronics/comms modules*o Add or remove integral indicators*o Add or remove external configuration buttons*Field replaceable in all electrical environments (including IS) except flameproof without violating agency approvals.With no performance effects, Honeywell’s unique modula rity results in lower inventory needs and lower overall operating costs.Digital Output OptionAn optional Digital Output (open collector type) is available on HART transmitters which can be used to activate external equipment when preset Alarm Setpoints are reached. The Digital Output can be set to monitor two independent setpoints based upon the analog value of the PV or upon device status.The following Alarm Types are available:1. PV High2. PV Low3. Critical Diagnostic Active4. Redundant Input Active**5. PV Rate of Change Alarm*6. PV Deviation Alarm*Alarms can be configured as latching or non-latching. Alarm Blocking is also available which allows start-up without the alarm energizing until it first reaches the operating region. Alarm Hysteresis is configurable from 0 to 100% of PV range.The Digital Output functionality and status is also available over the HART communications link.* These Alarm Types are available as part of the Advanced Diagnostics option. Rate of Change monitors the rate at which the PV is changing, configurable as either increasing or decreasing. Deviation monitors the PV delta from a separately configurable Setpoint value.** Available only via Communications Status.See Wiring Diagrams on page 16.Performance Specifications1,321. Digital Accuracy is accuracy of the digital value accessed by the Host system and the handheld communicator.2. Total analog accuracy is the sum of digital accuracy and output D/A Accuracy.3. Output D/A Accuracy is applicable to the 4 to 20 mA Signal output.4. For TC inputs, CJ accuracy shall be added to digital accuracy to calculate the total digital accuracy.5. These input types are not available on DE units.6. Custom Callendar-van Dusen is not available for Pt25 sensors.Differential Temperature MeasurementSmartLine Temperature supports differential temperature measurements between any two types of sensors.When the loop current mode is set to "Differential" then the input range is from A to B for sensor 1 & 2 whereA = Sensor 1 Minimum - Sensor 2 MaximumB = Sensor 1 Maximum - Sensor 2 MinimumCallendar - van Dusen Algorithm (CVD)The easy-to-use Callendar - van Dusen (CVD) algorithm allows the use of calibrated Platinum RTD sensors to increase the overall system accuracy. Simply enable the algorithm and then enter the four CVD coefficients supplied with the calibrated RTD sensor into the transmitter.Digital Accuracy for differential temperature measurementIf both the inputs are similar the digital accuracy equals 1.5 times the worst-case accuracy of either sensor type.For mixed input types, the digital accuracy is the sum of sensor 1 and sensor 2 digital accuracies.EMC Confirmity (CE, Marine and SIL)The STT850 device is compliant with IEC compliance EN 61326-1: 2013, EN IEC 61326-1: 2021 (CE) ; IEC 60533: 2015 / IACS Req. 1991/Rev.8 2021 (Marine) and IEC 61326-3-1: 2017 (SIL)Performance specifications under EMC conditions (CE and Marine):HART/DE Transmitter: Worst case deviation < 0.1% of full span (for both Analog and Digital).Foundation Fieldbus Transmitter: Worst case deviation < 1°C.Performance under Rated Conditions – All Models (continued)Parameter DescriptionStray Rejection Common ModeAC (50 or 60 Hz): 120 dB (with maximum source impedance of 100 ohms) or ±1 LSB (least significant bit) whichever is greater with line voltage applied.DC: 120 dB (with maximum source impedance of 50 ohms) or a ±1 LSB whichever isgreater with 120 Vdc applied.DC (to 1 KHz): 50 dB (with maximum source of impedance of 50 ohms) or ±1 LSBwhichever is greater with 50 Vac applied.Normal ModeAC (50 or 60 Hz): 60 dB (with 100% span peak-to-peak maximum)Operating Conditions – All ModelsParameter ReferenceConditionRated Condition Operative Limits Transportation andStorage︒C ︒F ︒C ︒F ︒C ︒F ︒C ︒FAmbient Temperature1STT850 25±1 77±2 -40 to 85 -40 to 185 -40 to 85 -40 to 185 -55 to 120 -67 to 248 Humidity %RH 10 to 55 0 to 100 0 to 100 0 to 100Supply Voltage Load Resistance HART Models: 11.8 to 42.4 Vdc at terminals (IS versions limited to 30 Vdc) 0 to 1,400 ohms (as shown in Figure 2)DE Models: 13.8 to 42.4 Vdc at terminals (IS versions limited to 30 Vdc)0 to 1,300 ohms (as shown in Figure 2)FF Models: 9.0 to 32.0 Vdc at terminals1 LCD Display operating temperature -20︒C to +70︒C . Storage temperature -30︒C to 80︒C.For DE, RImax =35* (power Supply Voltage – 15)For HART, RImax = 45.6* (Power Supply Voltage – 11.8)Figure 2 - Supply voltage and loop resistance chart & calculations(not applicable for Fieldbus)Communications Protocols & DiagnosticsHART ProtocolVersion:HART 7Power SupplyVoltage: 11.8 to 42.4Vdc at terminalsLoad: Maximum 1400 ohms See figure 2Minimum Load: 0 ohms. (For handheld communications a minimum load of 250 ohms is required)IEC 61508 Safety Certified SIL 2 and SIL 3Honeywell Digitally Enhanced (DE)DE is a Honeywell proprietary protocol which provides digital communications between Honeywell DE enabled field devices and Hosts.Power SupplyVoltage: 13.8 to 42.4Vdc at terminalsLoad: Maximum 1300 ohms See Figure 2Foundation Fieldbus (FF)Power Supply RequirementsVoltage: 9.0 to 32.0 Vdc at terminalsSteady State Current: 20 mASoftware Download Current: 29 mAP = PermanentI = InstantiableThe AI function block allows the user to configure the alarms to HIGH-HIGH, HIGH, LOW, or LOW-LOW with a variety of priority levels and hysteresis settings.All available function blocks adhere to FOUNDATION Fieldbus standards. PID blocks support ideal & robust PID algorithms with full implementation of Auto-tuning. Link Active SchedulerTransmitters can perform as a backup Link Active Scheduler (LAS) and take over when the host is disconnected. Acting as a LAS, the device ensures scheduled data transfers typically used for the regular, cyclic transfer of control loop data between devices on the Fieldbus.Number of Devices/SegmentEntity IS model: 15 devices/segmentSchedule Entries45 maximum schedule entries50 maximum LinksNumber of VCR’s: 50 maxCompliance Testing: Tested according to ITK 6.1.2Physical LayerComply with IEC 61158 standardSoftware DownloadUtilizes Class-3 of the Common Software Download procedure as per FF-883 which allows any field devices to receive software upgrades from any host.STT850 Smart Temperature 9 Standard DiagnosticsSTT850 top-level diagnostics are reported as either critical or non-critical as listed below. All diagnostics are readable via the DD/DTM tools. All critical diagnostics will appear on the Standard and Advanced integral displays, and non-critical diagnostics will appear on the Advanced integral display.Critical Diagnostics- Sensor Module Fault- Communications Module Fault- Sensor Communications Fault- Input 1 Fault- Input 2 FaultNon Critical Diagnostics (for Advanced Display only)- Cal 1 Correct- Cal 2 Correct- Sensor Temperature- Sensor 1 Health- Sensor 2 Health- Input 1 Range- Input 2 Range- CJ Range- Input 1- Input 2- Input 1 TB5 (For RTD and Ohm types only)- Input 1 TB6 (for RTD and Ohm types only)- Input TB7 (Input 1 or 2, for RTD and Ohm types only)- Input 1 TB8 (for 4-Wire RTD and Ohm types only)- Input 2 TB8 (for RTD and Ohm types only)- Input 2 TB9 (for RTD and Ohm types only)- Factory Calibration- Loop Supply Voltage (not available on Fieldbus)- Communications Module Temperature- DAC Temperature Compensation (not available on Fieldbus)- Sensor Communications- Display Setup (not for Fieldbus)- Excess Delta Alert10 STT850 Smart Temperature Approval Certifications:Notes1.Operating Parameters:4-20 mA/DE/HART (Loop Terminal)Voltage= 11 to 42 Vdc Current= 4-20 mA Normal (3.8 – 23 mA Faults)FF (Loop Terminal)Voltage= 9 to 32 VDC Current = 30 mA2.Intrinsically Safe Entity Parametersa. Analog/DE/HART Entity ValuesTransmitter with Terminal Block Single (50086421-003), Dual (50086421-004) Input revision AA or DO(50086421-006) Option revision W or Laterb. Foundation Fieldbus Entity ValuesFISCO ValuesTransmitter with Terminal Block Single (50086421-009), or Dual (50086421-010) Input revision S or LaterFISCO ValuesNote: Transmitter with Terminal Block revision F or later, the revision is on the label that is on the module.Wiring DiagramsDE- Single InputWiring DiagramRTD Thermocouple,mV and OhmConnectionsDE- Dual Input WiringDiagram1Thermocouple andRTD Connections1 Not applicable forsingle input sensorHART/FF – Single Input Wiring Diagram RTD Thermocouple, mV and Ohm ConnectionsHART/FF – Dual Input Wiring DiagramRTD Thermocouple, mV and Ohm ConnectionsHART/FF Dual Input Wiring Diagram Remote C/J and Mixed Sensors ConnectionsDigital Output Connections for mA Load (HART only) Digital Output Connections for PLC Counting Input (HART only)Mounting & Dimensional DrawingsTRANSMITTER ENCLOSURE CAN BE ROTATED A TOTAL OF 90O FROM THE STANDARD MOUNTING POSITIONFigure 3 – STT850 housing- Horizontal Wall MountingFigure 4 – STT850 Angle Bracket Pipe Mount - Horizontal & VerticalFigure 5 - STT850 Pipe Mount housing - Horizontal & Vertical .STT850 Smart Temperature 21 Mounting & Dimensional DrawingsReference Dimensions:millimetersinchesFigure 6 – STT850 housing dimensions22 STT850 Smart Temperature The Model Selection Guide is subject to change and is inserted into the specification as guidance only.Model Selection GuideSTT850 Smart Temperature 2324 STT850 Smart TemperatureFor more informationTo learn more about SmartLine Temperature, visit https://Or contact your Honeywell Account ManagerProcess Solutions Honeywell1250 W Sam Houston Pkwy S Houston, TX 77042Honeywell Control Systems LtdHoneywell House, Skimped Hill Lane Bracknell, England, RG12 1EB34-TT-03-14 August 2023©2023 Honeywell International Inc.Shanghai City Centre, 100 Jungi Road Shanghai, China 20061https://Sales and ServiceFor application assistance, current specifications, pricing, or name of the nearest Authorized Distributor, contact one of the offices below.ASIA PACIFICHoneywell Process Solutions, (TAC) hfs-tac-*********************AustraliaHoneywell LimitedPhone: +(61) 7-3846 1255 FAX: +(61) 7-3840 6481 Toll Free 1300-36-39-36 Toll Free Fax: 1300-36-04-70China – PRC - Shanghai Honeywell China Inc.Phone: (86-21) 5257-4568 Fax: (86-21) 6237-2826SingaporeHoneywell Pte Ltd.Phone: +(65) 6580 3278 Fax: +(65) 6445-3033South KoreaHoneywell Korea Co Ltd Phone: +(822) 799 6114 Fax: +(822) 792 9015EMEAHoneywell Process Solutions, Phone: + 80012026455 or +44 (0)1202645583Email: (Sales)***************************or (TAC)*****************************AME RICA’SHoneywell Process Solutions, Phone: (TAC) 1-800-423-9883 or 215/641-3610(Sales) 1-800-343-0228Email: (Sales)*************************** or (TAC)*****************************Specifications are subject to change without notice.。

三千多个植物学名词中英文对照1

盖高楼：全国科技名词审定委员会－植物学名词（1）盖高楼：全国科技名词审定委员会－植物学名词（2）01.001 植物学botany, plant science01.002 植物生物学plant biology01.003 植物个体生物学plant autobiology01.004 发育植物学developmental botany01.005 植物形态学plant morphology01.006 植物解剖学plant anatomy, phytotomy01.007 植物细胞学plant cytology01.008 植物细胞生物学plant cell biology01.009 植物细胞遗传学plant cytogenetics01.010 植物细胞形态学plant cell morphology01.011 植物细胞生理学plant cell physiology01.012 植物细胞社会学plant cell sociology01.013 植物细胞动力学plant cytodynamics01.014 植物染色体学plant chromosomology01.015 植物胚胎学plant embryology01.016 系统植物学systematic botany, plant systematics01.017 植物小分子系统学plant micromolecular systematics01.018 演化植物学evolutionary botany01.019 植物分类学plant taxonomy01.020 植物实验分类学plant experimental taxonomy01.021 植物化学分类学plant chemotaxonomy01.022 植物化学系统学plant chemosystematics 01.023 植物血清分类学plant serotaxonomy01.024 植物细胞分类学plant cellular taxonomy 01.025 植物数值分类学plant numerical taxonomy 01.026 植物分子分类学plant molecular taxonomy 01.027 植物病毒学plant virology01.028 藻类学phycology01.029 真菌学mycology01.030 地衣学lichenology01.031 苔藓植物学bryology01.032 蕨类植物学pteridology01.033 孢粉学palynology01.034 古植物学paleobotany01.035 植物生理学plant physiology01.036 植物化学phytochemistry01.037 植物生态学plant ecology, phytoecology01.038 植物地理学plant geography, phytogeography 01.039 植物气候学plant climatology01.040 植物病理学plant pathology, phytopathology 01.041 植物病原学plant aetiology01.042 植物毒理学plant toxicology01.043 植物历史学plant history01.044 民族植物学ethnobotany01.045 人文植物学humanistic botany 01.046 植物遗传学plant genetics01.047 植物发育遗传学plant phenogenetics 01.048 分子植物学molecular botany01.049 分类单位taxon 又称“分类群”。

SLATE Low Torque Actuator Series 商品说明书

INSTALLATION INSTRUCTIONS32M-06009-05SLATE™ Low Torque Actuator SeriesFOR COMMERCIAL AND INDUSTRIAL MODELS R8001M1050/U, R8001M1150/U, R8001M4050/U, R8001M4150/UAPPLICATIONSLATE brings configurable safety and programmable logic together into one single platform. The SLATE program can easily be customized for almost any application—offering virtually limitless development opportunities with far less complexity.The SLATE Low Torque Actuator series includescommercial- and industrial-grade 1/4-turn actuators available in 50 and 150 in/lb models with highlyrepeatable position accuracy designed specifically to integrate with the SLATE system. This series is well suited for the precise control of air and gas flow and can operate in a wide range of temperatures and environmental conditions.SLATE™ Low Torque Actuator can be easily mounted to the following valves using the mounting kits noted below. These kits can be ordered via .•Maxon CV Valve Series (1/2"–2")mounting kit #50123928-001•Honeywell V51E Valve Series (1-1/2"–2")mounting kit #50124386-001 and mounting kit #32003396-001•Honeywell V51E Valve Series (2-1/2"–4")mounting kit #50124386-001 and mounting kit #32003396-002•Honeywell V5197A Valve Series (3/4"–3")mounting kit #50124386-001FEATURES AND BENEFITS•Offered in two different configuration options:—NEMA 1 rated, operating in a temperaturerange of -18 to 158°F (-28 to 70°C) with 450 positions over a 90° span—NEMA 4 rated, operating in a temperaturerange of -40 to 158°F (-40 to 70°C) with 900 positions over a 90° span •Field-reversible clockwise and counterclockwise rotation operation.•Internal temperature, valve status, health diagnostics, and error codes reporting.•Robust, heavy-duty construction, continuous duty cycle-rated.•Closed loop position control via Modbus RS-485 communications as an input to the SLATE Fuel Air Ratio Module, part R8001C6001.•Dual 1/2-in knockout conduit connections.•1/2-in keyed output shaft with a 1/8-in square key.•Die-cast aluminum base with high-impact resistant, reinforced plastic cover.•Meets UL353 Safety for Limit Controls.•Meets UL1998 when used with R8001C6001 SLATE Fuel Air Ratio Module.APPROVALSSLATE Commercial ModelUnderwriters LaboratoriesMeets UL353 Safety for Limit Controls.Meets UL1998 when used with R8001C6001 SLATE Fuel Air Ratio Module.CE2009/142/EC: Gas Appliance Directive(EN 12067-2:2004, EN298-2012)SLATE™ LOW TORQUE ACTUATOR SERIES32M-06009—052SPECIFICATIONSSupply Voltage (Peak Current):DC model: 24VDC +10/-20%Power:50 in/lb: 10 Watts maximum 150 in/lb: 25 Watts maximum Rotation: Max span: 90° usableResolution:Commercial: 450 positions (0.2° resolution)Industrial: 900 positions (0.1° resolution)Control Deadband:Commercial: ±0.2 degrees Industrial ±0.1 degreesDimensions in in (mm): 6-11/16 x 5-29/64 x 5-29/64(170 x 138 x 138); See Fig. 1Weight: 3 Lbs. (1.4 Kg)Operating Temperature:-28 to +70°C (-18 to +158°F) for commercial mod-els; -40to +70°C (-40 to +158°F) for industrial models Storage Temperature: -40 to +80°C (-40°F to +176°F) Relative Humidity:0 to 99% non condensing (for commercial models)Vibration: Honeywell V2 test specification; 3 axes tested as follows:2-Hour Performance/Resonant Detection Sweep:Vibration sinusoidal: 5 Hz - 30 Hz;Amplitude: 0.012mil pk/pk75 mmVibration sinusoidal: 30 Hz – 300 Hz at 0.6GEndurance: 1.1G for 2 hours at resonant frequen-cies EMC: EN61000-6-1/2/3 (See Safety and Agency Approval Requirements), FCC Part 15, Level A EN55022, Level A Enclosure:NEMA1 (commercial models)NEMA 4 (industrial models)Models:Model Number DescriptionCommercialR8001M105050 in/lb Actuator NEMA 1 Enclosure R8001M1150150 in/lb Actuator NEMA 1Enclosure IndustrialR8001M405050 in/lb Actuator NEMA 4 Enclosure R8001M4150150 in/lb Actuator NEMA 4EnclosureTable 1. Model Specifications.Actuator Options/Specs Commercial ModelIndustrial Model50 in-lb R8001M1050150 in-lb R8001M115050 in-lb R8001M4050150 in-lb R8001M4150Communication RS-485 non-isolated RS-485 non-isolated RS-485 Isolated RS-485 Isolated Fault Annunciation Generic Alarm Generic Alarm Yes Yes Enhanced Data Logging None None Yes Yes Resolution .2 Degree .2 Degree .1 Degree .1 Degree Repeatability.2 Degree .2 Degree .1 Degree .1 Degree Duty Cycle (Act Availability)100%100%100%100%Opening Span 90 Degrees 90 Degrees 90 Degrees 90 Degrees 90 Degree Travel Time 30 sec 30 sec 15 sec max 15 sec max Minimum Operating Temperature-28°C (-18°F)-28°C (-18°F)-40°C (-40°F)-40°C (-40°F)Maximum Operating Temperature 70°C (158°F)70°C (158°F)70°C (158°F)70°C (158°F)Temp Sensor Yes; Alarm Only Yes; Alarm Only Yes; Alarm and Real Time Data Yes; Alarm and Real Time Data Output1/2-in Keyed Output Shaft 1/2-in Keyed Output Shaft 1/2-in Keyed Output Shaft 1/2-in Keyed Output Shaft Keyed Connection 1/8-in Square Key 1/8-in Square Key 1/8-in Square Key 1/8-in Square KeyConduit Connections1/2-in Conduit Knockouts (2) (Shipped Closed)1/2-in Conduit Knockouts (2) (Shipped Closed)1/2-in Conduit Knockouts (2) (Shipped Closed)1/2-in Conduit Knockouts (2) (Shipped Closed)SLATE™ LOW TORQUE ACTUATOR SERIES332M-06009—05Fig. 1. Dimensions in in (mm).INSTALLATION INSTRUCTIONSWARNINGRead CarefullyPlease read the operating and mounting instructions before using the equipment. Install the equipment in compliance with the prevailing regulations.Bedrijfs- en montagehandleiding voor gebruik goed lezen! Apparaat moet volgens degeldende voorschriften worden geïnstalleerd.Lire les instructions de montage et de service avant utilisation! L ’appareil doitimperativement être installé selon les règlementations en vigueur.Betriebs- und Montageanleitung vor Gebrauch lesen! Gerät muß nach den geltenden Vorschriften installiert werden.NOTICELanguage translations for this document are available at .Safety requirementsWARNINGSafety NoticeThe SLATE Actuator has been independently evaluated by Underwriters Laboratories toprovide position feedback to the SLATE Fuel Air Ratio Module. The safety of the overall system is ultimately the responsibility of: 1) Theupstream safety control that commands and monitors the SLATE Actuator, and 2) the trained commissioning engineer that configures the unit for system operation.WARNINGSafety HazardBefore operating this product, check all specifications and safety requirements toensure the product is suitable and safe for the intended application. In addition, read all installation, commissioning, and operating instructions. The SLATE Actuator must be set up and maintained in the field by qualified personnel. If the equipment is used in amanner not specified, the protection provided by the equipment may be impaired.SLATE™ LOW TORQUE ACTUATOR SERIES32M-06009—054MountingThe actuator assembly may be installed in any orientation.WARNINGKeep Free of Dust and Water•Maintain the integrity of the enclosure by using NEMA 4X rated dust- and water-tight electrical connectors.•Use cable-sealing grips and strain-relief loops for any cord or cable.•Plug unused conduit holes. Use internal sealing materials on all conduit connections. Moisture can have a harmful effect on device internals if permitted to enter through wiring connectors.•Ensure that the device connection is not at a low point of the conduit to avoidcondensation run-off into the housing; install a drip loop if necessary.•All cover screws should be tightened to the specified torque. See Fig. 4.•Cover screws should be checked periodically to ensure adequate sealing protection.If you are mounting the SLATE™ Low Torque Actuator using third party valves, it is important to follow the following assembly instructions:1.Ensure that the SLATE™ Low Torque actuatorhas sufficient torque for the valve's required break-away torque. Also consider the line pressure when making this calculation.2.Turn off the fuel supply upstream from theapplicable valve.3.Remove all external hardware from the thirdparty valve.4.The SLATE actuator's shaft is ½-in. diameterwith a 1/8-in. square key. For a smaller 3/8-in. valve shaft you must insert an adapter so that the two shafts are concentrically aligned, ensure that the set screws solidly contact both shafts.5.If the bracket assembly permits, attach thecoupling to the valve and the actuator first, ensuring exact alignment. After the coupling is tightened, assemble and tighten the mounting brackets. Do not tighten the mounting brackets first.6.Observe the actuator while it travels over itsentire range and ensure smooth operation. If sticking/binding is observed, or if Slate reports actuator error codes, the actuator shaft is not properly aligned and must be re-adjusted.Ensure the media temperature cannot exceed the valve or actuator ratings. Use a coupling with thermal breaks if required. If the possibility exists for radiant heating (such as a furnace application), install a thermal barrier.Ensure that pipe and ductwork are free of debris that could impair valve function.See Fig. 2 for the locations of the mounting holes. The mounting holes are threaded for M6 x 1 x 1/2-in (12mm) fasteners.Fig. 2. Mounting holes.Note the quadrant of the keyway and rotation direction. See Fig. 3.Fig. 3. Actuator rotation direction.NOTE:The SLATE Actuator ships CCW as default.Electrical installationWARNINGElectrical Shock Hazard.Can cause severe injury, death or equipment damage.Disconnect the power supply before beginning installation to prevent electrical shock and equipment damage. More than one power supply disconnect can be involved.Wiring terminalsFig. 4 indicates each wiring terminal and Table 2 identifies each terminal’s signal type and function.SLATE™ LOW TORQUE ACTUATOR SERIES532M-06009—05Fig. 4. Wiring terminals.To access the field wiring compartment for power and signal connections:1.Remove the 2 screws and cover from the top ofthe actuator housing.2.Pass all customer-supplied wires into the enclo-sure through the 2 conduit hubs.WARNINGEquipment DamageTo ensure physical protection as well aselectromagnetic immunity, the use of flexible, sunlight-resistant, jacketed, metallic, water-tight conduit is required. The conduit should be connected to earth ground on both ends.3.One or both conduit holes may be used when wiring an actuator.4.In addition to a grounded conduit, the use of shielded, twisted-pair cable is strongly recom-mended for DC power and signal wires. The shield drain wires should be landed to chas-sis/earth on both ends of the cable, but ONLY if a conduit is also grounded on both ends. In other cases, earth the shields at actuator end only.Input powerIMPORTANTUse DC power only.Use cable rated for the temperatures and voltages required by the application. Use a gauge of wire to minimize voltage loss (droop) over long cable runs, especially at full current load. Ensure that voltage specifications are met under all conditions. See Table 2.A fuse or breaker should be installed at the power source. If the power supply is not factory-supplied, a SELV (Safety Extra Low Voltage) rated supply with regulated output must be provided.Communication (Modbus over RS-485)Use appropriate communication cable. A network will consist of a customer’s Modbus master (withtermination) and one or more actuator slaves. See SLATE documentation for wiring specifics.NOTE:On commercial models only:Do not wire the non-isolated common terminal to the Slate system; leave itunconnected. Instead, wire the 24V- of the actuator supply to Pin 2 of the SlateSub-Base. If all actuators share the same supply, only one connection is work layouts should be arranged so thatbranch/homerun length does not exceed 300 feet for commercial actuators, or 2000 feet for industrial actuators.SLATE™ LOW TORQUE ACTUATOR SERIES32M-06009—0561 Do not wire the non-isolated common terminal to the Slate system; leave it unconnected. Instead, wire the24V- of the actuator supply to Pin 2 of the Slate Sub-Base. If all actuators share the same supply, only one con-nection is needed.Table 2. Wiring Terminal Identification.TypeTerminalDescriptionWiringPE (Protective Earth)Chassis ground screw Chassis connection for mains power and shield/drain wiresFollow local codes for safety earth installation. See Electrical installation section for shield drain installation instructions.DC power terminals 24V+24VDC positive terminal Shielded twisted pair cable isrecommended. A replaceable 2A fuse is provided on all actuators. Use a slow blow fuse if additional external fusing is desired. Required gauges are:Up to 80 ft: 24 AWG Up to 120 ft: 22 AWG Up to 500 ft: 16 AWG Up to 800 ft: 14 AWG Up to 1200 ft: 12 AWG24V-24VDC negative terminalLow voltage communication (Modbus over RS-485)Industrial models only: R8001M4050, R8001M4150RS485 In+Isolated RS-485: positive Shielded twisted pair cable with a separate common wire is recommended. See Electrical installation section for length limitations. Use 12–24 AWG wire.NOTE:Shield should be tied to chas-sis at Actuator side; do not connect at SLATE (control-ler) side.RS485 In-Isolated RS-485: negative RS485COM Isolated RS-485: commonNOTE:Must be connected forreliable performance.Low voltage communication (Modbus over RS-485)Commercial modelsonly:R8001M1050, R8001M1150RS485 In+Non-isolated RS-485: positiveRS485 In-Non-isolated RS-485: negative RS485COM Non-isolated RS-485: common See note 1SLATE™ LOW TORQUE ACTUATOR SERIES732M-06009—05OPERATING INSTRUCTIONS The SLATE Actuator is designed specifically for the SLATE Fuel Air Ratio Module. For actuator operation and programming information, see the SLATE Fuel Air Ratio Module document 32-00006 and other SLATE system documentation (Base Module document 32-00005, and System Checkout guide 32-00016).Read the instruction manual carefully before initiating the start-up and adjustment procedure. Verify that all of the equipment associated with and necessary to the safe operation of the system has been installed correctly, that all pre-commissioning checks have been carried out successfully and that all safety-related aspects of the installation are properly addressed.OverviewSLATE Actuator provides multiple methods foractuator commissioning, precise closed-loop valve or damper position control, and health monitoring.•Position can be commanded via Modbus using the SLATE Fuel Air Ratio Module.•Commissioning is accomplished through the SLATE Fuel Air Ratio Module.TROUBLESHOOTINGIf the two shafts are not perfectly and concentrically aligned, additional binding and torque will beintroduced into the assembly causing error codes to be sent from the SLATE actuator to the SLATE Fuel Air Ratio Module resulting in an inability to properly commission the system. If you are receiving actuator error codes either on the SLATE main module or in the error code register, check the mounting brackets and coupling's alignment and make necessary adjustments.Alarm and lockout event reportingSLATE alarm and lockout codes are accessed through the SLATE Fuel Air Ratio Module or using the SLATE touchscreen display. See documents 32-00013 and 32-00006 for more information.The Low-Torque Actuators also display statusmessages through LED blinks. The LED is on the PCB inside the unit. These can be used for troubleshooting purposes.The cover of the Low-Torque Actuators must be removed to see the two LEDs:•G reen LED: displays status, including alarm codes •Yellow LED: displays communication activity (on RS-485, bus is working and actuator is communicating with SLATE system)The normal and error codes are shown in Table 3.Table 3. Alarm LED Codes.LED code Error CharacteristicActionContinuous Blinking Normal State – Ready to operate None.1Out of range – Actuator is out of normal operating quadrant Command actuator to normal operational range.2Not calibrated – Actuator not (Factory) calibrated Factory calibration data lost; replace actuator.3Low Voltage Check actuator input voltage.4High TemperatureReduce ambient temperature; shield actuator from heat sources.5Mechanical binding, electrical shorts, or internal electronics fault.Check all cables and electrical connections; check for debris or water on electronics; check for mechanical binding or slipping; if persistent, replace actuator.5 or Dark Plus Continuous ResetLockoutCheck power; replace actuator.For More InformationThe Honeywell Thermal Solutions family of products includes Honeywell Combustion Safety, Eclipse, Exothermics, Hauck, Kromschröder and Maxon. To learn more about our products, visit or contact your Honeywell Sales Engineer.Honeywell Process SolutionsHoneywell Thermal Solutions (HTS) 1250 West Sam Houston Parkway South Houston, TX 77042ThermalSolutions.honeywellSLATE™ LOW TORQUE ACTUATOR SERIES® U.S. Registered Trademark© 2017 Honeywell International Inc. 32M-06009—05 M.S. Rev. 07-17 Printed in United StatesTable 4 shows information about Lockout conditions.Table 4. Lockout Conditions.Lockout Code Lockout CharacteristicComments1RAM Test of internal memory failed 2RAM DMA Test of internal memory failed 3Flash Memory Program corruption4Watchdog Startup Internal watchdog unit failure 5Safety Variables Safety data corruption 6Stack Overflow Program execution error 7System Tick Program execution error 8Main Loop Program execution error 9Processor FaultInstruction test failure 10Processor Fault – MemoryRAM/ROM failure。

专八英语阅读

英语专业八级考试TEM-8阅读理解练习册（1）(英语专业2012级)UNIT 1Text AEvery minute of every day, what ecologist生态学家James Carlton calls a global ―conveyor belt‖, redistributes ocean organisms生物.It’s planetwide biological disruption生物的破坏that scientists have barely begun to understand.Dr. Carlton —an oceanographer at Williams College in Williamstown,Mass.—explains that, at any given moment, ―There are several thousand marine species traveling… in the ballast water of ships.‖ These creatures move from coastal waters where they fit into the local web of life to places where some of them could tear that web apart. This is the larger dimension of the infamous无耻的，邪恶的invasion of fish-destroying, pipe-clogging zebra mussels有斑马纹的贻贝.Such voracious贪婪的invaders at least make their presence known. What concerns Carlton and his fellow marine ecologists is the lack of knowledge about the hundreds of alien invaders that quietly enter coastal waters around the world every day. Many of them probably just die out. Some benignly亲切地，仁慈地—or even beneficially — join the local scene. But some will make trouble.In one sense, this is an old story. Organisms have ridden ships for centuries. They have clung to hulls and come along with cargo. What’s new is the scale and speed of the migrations made possible by the massive volume of ship-ballast water压载水— taken in to provide ship stability—continuously moving around the world…Ships load up with ballast water and its inhabitants in coastal waters of one port and dump the ballast in another port that may be thousands of kilometers away. A single load can run to hundreds of gallons. Some larger ships take on as much as 40 million gallons. The creatures that come along tend to be in their larva free-floating stage. When discharged排出in alien waters they can mature into crabs, jellyfish水母, slugs鼻涕虫，蛞蝓, and many other forms.Since the problem involves coastal species, simply banning ballast dumps in coastal waters would, in theory, solve it. Coastal organisms in ballast water that is flushed into midocean would not survive. Such a ban has worked for North American Inland Waterway. But it would be hard to enforce it worldwide. Heating ballast water or straining it should also halt the species spread. But before any such worldwide regulations were imposed, scientists would need a clearer view of what is going on.The continuous shuffling洗牌of marine organisms has changed the biology of the sea on a global scale. It can have devastating effects as in the case of the American comb jellyfish that recently invaded the Black Sea. It has destroyed that sea’s anchovy鳀鱼fishery by eating anchovy eggs. It may soon spread to western and northern European waters.The maritime nations that created the biological ―conveyor belt‖ should support a coordinated international effort to find out what is going on and what should be done about it. (456 words)1.According to Dr. Carlton, ocean organism‟s are_______.A.being moved to new environmentsB.destroying the planetC.succumbing to the zebra musselD.developing alien characteristics2.Oceanographers海洋学家are concerned because_________.A.their knowledge of this phenomenon is limitedB.they believe the oceans are dyingC.they fear an invasion from outer-spaceD.they have identified thousands of alien webs3.According to marine ecologists, transplanted marinespecies____________.A.may upset the ecosystems of coastal watersB.are all compatible with one anotherC.can only survive in their home watersD.sometimes disrupt shipping lanes4.The identified cause of the problem is_______.A.the rapidity with which larvae matureB. a common practice of the shipping industryC. a centuries old speciesD.the world wide movement of ocean currents5.The article suggests that a solution to the problem__________.A.is unlikely to be identifiedB.must precede further researchC.is hypothetically假设地，假想地easyD.will limit global shippingText BNew …Endangered‟ List Targets Many US RiversIt is hard to think of a major natural resource or pollution issue in North America today that does not affect rivers.Farm chemical runoff残渣, industrial waste, urban storm sewers, sewage treatment, mining, logging, grazing放牧,military bases, residential and business development, hydropower水力发电,loss of wetlands. The list goes on.Legislation like the Clean Water Act and Wild and Scenic Rivers Act have provided some protection, but threats continue.The Environmental Protection Agency (EPA) reported yesterday that an assessment of 642,000 miles of rivers and streams showed 34 percent in less than good condition. In a major study of the Clean Water Act, the Natural Resources Defense Council last fall reported that poison runoff impairs损害more than 125,000 miles of rivers.More recently, the NRDC and Izaak Walton League warned that pollution and loss of wetlands—made worse by last year’s flooding—is degrading恶化the Mississippi River ecosystem.On Tuesday, the conservation group保护组织American Rivers issued its annual list of 10 ―endangered‖ and 20 ―threatened‖ rivers in 32 states, the District of Colombia, and Canada.At the top of the list is the Clarks Fork of the Yellowstone River, whereCanadian mining firms plan to build a 74-acre英亩reservoir水库，蓄水池as part of a gold mine less than three miles from Yellowstone National Park. The reservoir would hold the runoff from the sulfuric acid 硫酸used to extract gold from crushed rock.―In the event this tailings pond failed, the impact to th e greater Yellowstone ecosystem would be cataclysmic大变动的，灾难性的and the damage irreversible不可逆转的.‖ Sen. Max Baucus of Montana, chairman of the Environment and Public Works Committee, wrote to Noranda Minerals Inc., an owner of the ― New World Mine‖.Last fall, an EPA official expressed concern about the mine and its potential impact, especially the plastic-lined storage reservoir. ― I am unaware of any studies evaluating how a tailings pond尾矿池，残渣池could be maintained to ensure its structural integrity forev er,‖ said Stephen Hoffman, chief of the EPA’s Mining Waste Section. ―It is my opinion that underwater disposal of tailings at New World may present a potentially significant threat to human health and the environment.‖The results of an environmental-impact statement, now being drafted by the Forest Service and Montana Department of State Lands, could determine the mine’s future…In its recent proposal to reauthorize the Clean Water Act, the Clinton administration noted ―dramatically improved water quality since 1972,‖ when the act was passed. But it also reported that 30 percent of riverscontinue to be degraded, mainly by silt泥沙and nutrients from farm and urban runoff, combined sewer overflows, and municipal sewage城市污水. Bottom sediments沉积物are contaminated污染in more than 1,000 waterways, the administration reported in releasing its proposal in January. Between 60 and 80 percent of riparian corridors (riverbank lands) have been degraded.As with endangered species and their habitats in forests and deserts, the complexity of ecosystems is seen in rivers and the effects of development----beyond the obvious threats of industrial pollution, municipal waste, and in-stream diversions改道to slake消除the thirst of new communities in dry regions like the Southwes t…While there are many political hurdles障碍ahead, reauthorization of the Clean Water Act this year holds promise for US rivers. Rep. Norm Mineta of California, who chairs the House Committee overseeing the bill, calls it ―probably the most important env ironmental legislation this Congress will enact.‖ (553 words)6.According to the passage, the Clean Water Act______.A.has been ineffectiveB.will definitely be renewedC.has never been evaluatedD.was enacted some 30 years ago7.“Endangered” rivers are _________.A.catalogued annuallyB.less polluted than ―threatened rivers‖C.caused by floodingD.adjacent to large cities8.The “cataclysmic” event referred to in paragraph eight would be__________.A. fortuitous偶然的，意外的B. adventitious外加的，偶然的C. catastrophicD. precarious不稳定的，危险的9. The owners of the New World Mine appear to be______.A. ecologically aware of the impact of miningB. determined to construct a safe tailings pondC. indifferent to the concerns voiced by the EPAD. willing to relocate operations10. The passage conveys the impression that_______.A. Canadians are disinterested in natural resourcesB. private and public environmental groups aboundC. river banks are erodingD. the majority of US rivers are in poor conditionText CA classic series of experiments to determine the effects ofoverpopulation on communities of rats was reported in February of 1962 in an article in Scientific American. The experiments were conducted by a psychologist, John B. Calhoun and his associates. In each of these experiments, an equal number of male and female adult rats were placed in an enclosure and given an adequate supply of food, water, and other necessities. The rat populations were allowed to increase. Calhoun knew from experience approximately how many rats could live in the enclosures without experiencing stress due to overcrowding. He allowed the population to increase to approximately twice this number. Then he stabilized the population by removing offspring that were not dependent on their mothers. He and his associates then carefully observed and recorded behavior in these overpopulated communities. At the end of their experiments, Calhoun and his associates were able to conclude that overcrowding causes a breakdown in the normal social relationships among rats, a kind of social disease. The rats in the experiments did not follow the same patterns of behavior as rats would in a community without overcrowding.The females in the rat population were the most seriously affected by the high population density: They showed deviant异常的maternal behavior; they did not behave as mother rats normally do. In fact, many of the pups幼兽，幼崽, as rat babies are called, died as a result of poor maternal care. For example, mothers sometimes abandoned their pups,and, without their mothers' care, the pups died. Under normal conditions, a mother rat would not leave her pups alone to die. However, the experiments verified that in overpopulated communities, mother rats do not behave normally. Their behavior may be considered pathologically 病理上，病理学地diseased.The dominant males in the rat population were the least affected by overpopulation. Each of these strong males claimed an area of the enclosure as his own. Therefore, these individuals did not experience the overcrowding in the same way as the other rats did. The fact that the dominant males had adequate space in which to live may explain why they were not as seriously affected by overpopulation as the other rats. However, dominant males did behave pathologically at times. Their antisocial behavior consisted of attacks on weaker male,female, and immature rats. This deviant behavior showed that even though the dominant males had enough living space, they too were affected by the general overcrowding in the enclosure.Non-dominant males in the experimental rat communities also exhibited deviant social behavior. Some withdrew completely; they moved very little and ate and drank at times when the other rats were sleeping in order to avoid contact with them. Other non-dominant males were hyperactive; they were much more active than is normal, chasing other rats and fighting each other. This segment of the rat population, likeall the other parts, was affected by the overpopulation.The behavior of the non-dominant males and of the other components of the rat population has parallels in human behavior. People in densely populated areas exhibit deviant behavior similar to that of the rats in Calhoun's experiments. In large urban areas such as New York City, London, Mexican City, and Cairo, there are abandoned children. There are cruel, powerful individuals, both men and women. There are also people who withdraw and people who become hyperactive. The quantity of other forms of social pathology such as murder, rape, and robbery also frequently occur in densely populated human communities. Is the principal cause of these disorders overpopulation? Calhoun’s experiments suggest that it might be. In any case, social scientists and city planners have been influenced by the results of this series of experiments.11. Paragraph l is organized according to__________.A. reasonsB. descriptionC. examplesD. definition12．Calhoun stabilized the rat population_________.A. when it was double the number that could live in the enclosure without stressB. by removing young ratsC. at a constant number of adult rats in the enclosureD. all of the above are correct13.W hich of the following inferences CANNOT be made from theinformation inPara. 1?A. Calhoun's experiment is still considered important today.B. Overpopulation causes pathological behavior in rat populations.C. Stress does not occur in rat communities unless there is overcrowding.D. Calhoun had experimented with rats before.14. Which of the following behavior didn‟t happen in this experiment?A. All the male rats exhibited pathological behavior.B. Mother rats abandoned their pups.C. Female rats showed deviant maternal behavior.D. Mother rats left their rat babies alone.15. The main idea of the paragraph three is that __________.A. dominant males had adequate living spaceB. dominant males were not as seriously affected by overcrowding as the otherratsC. dominant males attacked weaker ratsD. the strongest males are always able to adapt to bad conditionsText DThe first mention of slavery in the statutes法令，法规of the English colonies of North America does not occur until after 1660—some forty years after the importation of the first Black people. Lest we think that existed in fact before it did in law, Oscar and Mary Handlin assure us, that the status of B lack people down to the 1660’s was that of servants. A critique批判of the Handlins’ interpretation of why legal slavery did not appear until the 1660’s suggests that assumptions about the relation between slavery and racial prejudice should be reexamined, and that explanation for the different treatment of Black slaves in North and South America should be expanded.The Handlins explain the appearance of legal slavery by arguing that, during the 1660’s, the position of white servants was improving relative to that of black servants. Thus, the Handlins contend, Black and White servants, heretofore treated alike, each attained a different status. There are, however, important objections to this argument. First, the Handlins cannot adequately demonstrate that t he White servant’s position was improving, during and after the 1660’s; several acts of the Maryland and Virginia legislatures indicate otherwise. Another flaw in the Handlins’ interpretation is their assumption that prior to the establishment of legal slavery there was no discrimination against Black people. It is true that before the 1660’s Black people were rarely called slaves. But this shouldnot overshadow evidence from the 1630’s on that points to racial discrimination without using the term slavery. Such discrimination sometimes stopped short of lifetime servitude or inherited status—the two attributes of true slavery—yet in other cases it included both. The Handlins’ argument excludes the real possibility that Black people in the English colonies were never treated as the equals of White people.The possibility has important ramifications后果，影响.If from the outset Black people were discriminated against, then legal slavery should be viewed as a reflection and an extension of racial prejudice rather than, as many historians including the Handlins have argued, the cause of prejudice. In addition, the existence of discrimination before the advent of legal slavery offers a further explanation for the harsher treatment of Black slaves in North than in South America. Freyre and Tannenbaum have rightly argued that the lack of certain traditions in North America—such as a Roman conception of slavery and a Roman Catholic emphasis on equality— explains why the treatment of Black slaves was more severe there than in the Spanish and Portuguese colonies of South America. But this cannot be the whole explanation since it is merely negative, based only on a lack of something. A more compelling令人信服的explanation is that the early and sometimes extreme racial discrimination in the English colonies helped determine the particular nature of the slavery that followed. (462 words)16. Which of the following is the most logical inference to be drawn from the passage about the effects of “several acts of the Maryland and Virginia legislatures” (Para.2) passed during and after the 1660‟s?A. The acts negatively affected the pre-1660’s position of Black as wellas of White servants.B. The acts had the effect of impairing rather than improving theposition of White servants relative to what it had been before the 1660’s.C. The acts had a different effect on the position of white servants thandid many of the acts passed during this time by the legislatures of other colonies.D. The acts, at the very least, caused the position of White servants toremain no better than it had been before the 1660’s.17. With which of the following statements regarding the status ofBlack people in the English colonies of North America before the 1660‟s would the author be LEAST likely to agree?A. Although black people were not legally considered to be slaves,they were often called slaves.B. Although subject to some discrimination, black people had a higherlegal status than they did after the 1660’s.C. Although sometimes subject to lifetime servitude, black peoplewere not legally considered to be slaves.D. Although often not treated the same as White people, black people,like many white people, possessed the legal status of servants.18. According to the passage, the Handlins have argued which of thefollowing about the relationship between racial prejudice and the institution of legal slavery in the English colonies of North America?A. Racial prejudice and the institution of slavery arose simultaneously.B. Racial prejudice most often the form of the imposition of inheritedstatus, one of the attributes of slavery.C. The source of racial prejudice was the institution of slavery.D. Because of the influence of the Roman Catholic Church, racialprejudice sometimes did not result in slavery.19. The passage suggests that the existence of a Roman conception ofslavery in Spanish and Portuguese colonies had the effect of _________.A. extending rather than causing racial prejudice in these coloniesB. hastening the legalization of slavery in these colonies.C. mitigating some of the conditions of slavery for black people in these coloniesD. delaying the introduction of slavery into the English colonies20. The author considers the explanation put forward by Freyre andTannenbaum for the treatment accorded B lack slaves in the English colonies of North America to be _____________.A. ambitious but misguidedB. valid有根据的but limitedC. popular but suspectD. anachronistic过时的，时代错误的and controversialUNIT 2Text AThe sea lay like an unbroken mirror all around the pine-girt, lonely shores of Orr’s Island. Tall, kingly spruce s wore their regal王室的crowns of cones high in air, sparkling with diamonds of clear exuded gum流出的树胶; vast old hemlocks铁杉of primeval原始的growth stood darkling in their forest shadows, their branches hung with long hoary moss久远的青苔;while feathery larches羽毛般的落叶松,turned to brilliant gold by autumn frosts, lighted up the darker shadows of the evergreens. It was one of those hazy朦胧的, calm, dissolving days of Indian summer, when everything is so quiet that the fainest kiss of the wave on the beach can be heard, and white clouds seem to faint into the blue of the sky, and soft swathing一长条bands of violet vapor make all earth look dreamy, and give to the sharp, clear-cut outlines of the northern landscape all those mysteries of light and shade which impart such tenderness to Italian scenery.The funeral was over,--- the tread鞋底的花纹/ 踏of many feet, bearing the heavy burden of two broken lives, had been to the lonely graveyard, and had come back again,--- each footstep lighter and more unconstrained不受拘束的as each one went his way from the great old tragedy of Death to the common cheerful of Life.The solemn black clock stood swaying with its eternal ―tick-tock, tick-tock,‖ in the kitchen of the brown house on Orr’s Island. There was there that sense of a stillness that can be felt,---such as settles down on a dwelling住处when any of its inmates have passed through its doors for the last time, to go whence they shall not return. The best room was shut up and darkened, with only so much light as could fall through a little heart-shaped hole in the window-shutter,---for except on solemn visits, or prayer-meetings or weddings, or funerals, that room formed no part of the daily family scenery.The kitchen was clean and ample, hearth灶台, and oven on one side, and rows of old-fashioned splint-bottomed chairs against the wall. A table scoured to snowy whiteness, and a little work-stand whereon lay the Bible, the Missionary Herald, and the Weekly Christian Mirror, before named, formed the principal furniture. One feature, however, must not be forgotten, ---a great sea-chest水手用的储物箱,which had been the companion of Zephaniah through all the countries of the earth. Old, and battered破旧的，磨损的, and unsightly难看的it looked, yet report said that there was good store within which men for the most part respect more than anything else; and, indeed it proved often when a deed of grace was to be done--- when a woman was suddenly made a widow in a coast gale大风，狂风, or a fishing-smack小渔船was run down in the fogs off the banks, leaving in some neighboring cottage a family of orphans,---in all such cases, the opening of this sea-chest was an event of good omen 预兆to the bereaved丧亲者;for Zephaniah had a large heart and a large hand, and was apt有…的倾向to take it out full of silver dollars when once it went in. So the ark of the covenant约柜could not have been looked on with more reverence崇敬than the neighbours usually showed to Captain Pennel’s sea-chest.1. The author describes Orr‟s Island in a(n)______way.A.emotionally appealing, imaginativeB.rational, logically preciseC.factually detailed, objectiveD.vague, uncertain2.According to the passage, the “best room”_____.A.has its many windows boarded upB.has had the furniture removedC.is used only on formal and ceremonious occasionsD.is the busiest room in the house3.From the description of the kitchen we can infer that thehouse belongs to people who_____.A.never have guestsB.like modern appliancesC.are probably religiousD.dislike housework4.The passage implies that_______.A.few people attended the funeralB.fishing is a secure vocationC.the island is densely populatedD.the house belonged to the deceased5.From the description of Zephaniah we can see thathe_________.A.was physically a very big manB.preferred the lonely life of a sailorC.always stayed at homeD.was frugal and saved a lotText BBasic to any understanding of Canada in the 20 years after the Second World War is the country' s impressive population growth. For every three Canadians in 1945, there were over five in 1966. In September 1966 Canada's population passed the 20 million mark. Most of this surging growth came from natural increase. The depression of the 1930s and the war had held back marriages, and the catching-up process began after 1945. The baby boom continued through the decade of the 1950s, producing a population increase of nearly fifteen percent in the five years from 1951 to 1956. This rate of increase had been exceeded only once before in Canada's history, in the decade before 1911 when the prairies were being settled. Undoubtedly, the good economic conditions of the 1950s supported a growth in the population, but the expansion also derived from a trend toward earlier marriages and an increase in the average size of families; In 1957 the Canadian birth rate stood at 28 per thousand, one of the highest in the world. After the peak year of 1957, thebirth rate in Canada began to decline. It continued falling until in 1966 it stood at the lowest level in 25 years. Partly this decline reflected the low level of births during the depression and the war, but it was also caused by changes in Canadian society. Young people were staying at school longer, more women were working; young married couples were buying automobiles or houses before starting families; rising living standards were cutting down the size of families. It appeared that Canada was once more falling in step with the trend toward smaller families that had occurred all through theWestern world since the time of the Industrial Revolution. Although the growth in Canada’s population had slowed down by 1966 (the cent), another increase in the first half of the 1960s was only nine percent), another large population wave was coming over the horizon. It would be composed of the children of the children who were born during the period of the high birth rate prior to 1957.6. What does the passage mainly discuss?A. Educational changes in Canadian society.B. Canada during the Second World War.C. Population trends in postwar Canada.D. Standards of living in Canada.7. According to the passage, when did Canada's baby boom begin?A. In the decade after 1911.B. After 1945.C. During the depression of the 1930s.D. In 1966.8. The author suggests that in Canada during the 1950s____________.A. the urban population decreased rapidlyB. fewer people marriedC. economic conditions were poorD. the birth rate was very high9. When was the birth rate in Canada at its lowest postwar level?A. 1966.B. 1957.C. 1956.D. 1951.10. The author mentions all of the following as causes of declines inpopulation growth after 1957 EXCEPT_________________.A. people being better educatedB. people getting married earlierC. better standards of livingD. couples buying houses11.I t can be inferred from the passage that before the IndustrialRevolution_______________.A. families were largerB. population statistics were unreliableC. the population grew steadilyD. economic conditions were badText CI was just a boy when my father brought me to Harlem for the first time, almost 50 years ago. We stayed at the hotel Theresa, a grand brick structure at 125th Street and Seventh avenue. Once, in the hotel restaurant, my father pointed out Joe Louis. He even got Mr. Brown, the hotel manager, to introduce me to him, a bit punchy强力的but still champ焦急as fast as I was concerned.Much has changed since then. Business and real estate are booming. Some say a new renaissance is under way. Others decry责难what they see as outside forces running roughshod肆意践踏over the old Harlem. New York meant Harlem to me, and as a young man I visited it whenever I could. But many of my old haunts are gone. The Theresa shut down in 1966. National chains that once ignored Harlem now anticipate yuppie money and want pieces of this prime Manhattan real estate. So here I am on a hot August afternoon, sitting in a Starbucks that two years ago opened a block away from the Theresa, snatching抓取，攫取at memories between sips of high-priced coffee. I am about to open up a piece of the old Harlem---the New York Amsterdam News---when a tourist。

男女差异英语up braining作文

男女差异英语up braining作文Gender differences in upbringing have been a topic of discussion for many years. These differences can significantly influence a child's development, shaping their personality, interests, and future opportunities. While every child is unique, societal expectations and cultural norms often dictate how boys and girls are raised.Traditionally, boys have been encouraged to be strong, assertive, and independent. They are often given toys that promote physical activity and competition, such as trucks and action figures. This upbringing fosters traits like leadership and risk-taking. On the other hand, girls are often raised to be nurturing, cooperative, and empathetic. They are typically given dolls and playsets that emphasize caregiving and domestic skills. This can lead to the development of traits like compassion and collaboration.These differing expectations can also affect educational choices and career paths. Boys may feel pressured to pursue fields like engineering or sports, while girls might be steered towards professions in education or healthcare. Such patterns can lead to gender imbalances in various industries, limiting opportunitiesfor both genders.However, it is essential to recognize that these are generalizations and not every child fits these molds. Many parents are actively working to break down these stereotypes by encouraging their children to explore interests regardless of gender. For instance, girls are increasingly pursuing STEM (science, technology, engineering, and mathematics) careers, while boys are becoming more involved in nurturing roles, such as teaching or nursing.In conclusion, while gender differences in upbringing can have profound effects on a child's development, it is crucial to promote an environment that values individuality over stereotypes. By allowing children to explore their interests freely, we can help them develop into well-rounded individuals, regardless of their gender.中文翻译：男女差异的教育多年来一直是一个讨论的话题。

小学上册第六次英语第二单元测验试卷

小学上册英语第二单元测验试卷英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.I can ______ (表达) gratitude towards others.2. A _____ can vary in brightness and color.3. A hamster's whiskers help it sense ______ (周围的环境).4.The manatee is often found in warm ______ (水域).5.The ______ shares knowledge about art.6.I enjoy _______ (参与)学校活动。

7.Birds can _______ in the sky.8.What is the name of the famous statue in New York Harbor?A. Christ the RedeemerB. Eiffel TowerC. Statue of LibertyD. Big Ben9.I like to collaborate with friends using my ________ (玩具).10.I see a ___ on the shelf. (book)11.My cousin is a ______. She loves to travel.12.What is the capital of Denmark?A. OsloB. StockholmC. CopenhagenD. Helsinki13.I can create stories with my __________ (玩具名).14.The ________ (环保意识) is growing worldwide.15.The ________ (herb) adds flavor to the food.16. A wave's amplitude affects its ______.17.What do you call the process of a plant growing?A. GerminationB. PhotosynthesisC. DigestionD. Respiration18.The ancient Egyptians believed in many _____ gods.19. A ______ (兔子) can hop very high.20.The ______ (小鱼) swims happily among the colorful coral in the ______ (海洋).21.I like to write ______ (故事) and share them with my friends. It’s fun to come up with new characters and adventures.22.My mom calls me _______ (我妈妈叫我_______).23.What is the name of the first man on the moon?A. Neil ArmstrongB. Buzz AldrinC. Yuri GagarinD. John GlennA24.The Himalayas continue to rise because of tectonic ______.25.We learned about __________ (地理) in school.26. A solution can become saturated when it contains a solid that will not ______.27.The ________ likes to play in the sun.28. A ___ (小鹰) flies high in the sky.29.The ancient Romans held gladiatorial games in the ______ (斗兽场).30.Astronomers believe that dark matter makes up most of the mass in the _______.31.My best friend is ______. We have been friends since we were ______ years old. We met at ______ and instantly connected.32.What do we call a piece of land surrounded by water?A. IslandB. PeninsulaC. MountainD. ValleyA33.What is the capital of India?A. MumbaiB. DelhiC. KolkataD. Chennai34.My favorite cartoon character is ______.35. A dilute solution has a ______ amount of solute.36.The chemical formula for sodium acetate is ______.37.I love visiting the aquarium to learn about ________ (海洋生物) and their habitats.38.Chinchillas have very soft ________________ (毛发).39.I enjoy _______ (进行探索) in my backyard.40. A base can turn red litmus paper ______.41.Every Christmas, I hope for a new ____. (玩具名称)42.greenhouse gases) trap heat in the atmosphere. The ____43.The element with atomic number is __________.44.What is 5 x 5?A. 10B. 15C. 25D. 30C45.The dog is ________ at the door.46.The ______ (繁殖) process can be complex.47.What is the largest mammal in the world?A. ElephantB. Blue WhaleC. GiraffeD. HippopotamusB48.I have a ________ that I can cuddle with.49.The first man to reach the North Pole was _______. (皮尔·阿蒙森)50.What do you call the process of creating a new computer program?A. CodingB. DesigningC. ProgrammingD. All of the above51.My ______ enjoys learning new things.52.What do we call the layer of gases surrounding the Earth?A. TroposphereB. AtmosphereC. StratosphereD. ExosphereB53.How many strings does a guitar have?A. FourB. FiveC. SixD. Seven54.How many fingers do humans typically have?A. 8B. 10C. 12D. 1455.The process of ionization involves the formation of ______.56.My favorite fruit is _____ (banana/apple).57.The process of rusting is an example of ______.58.The __________ (历史的连结) strengthens bonds.59.The __________ (历史的启迪) guides our journey.60.What do we call a story that is passed down through generations?A. LegendB. FolktaleC. MythD. All of the aboveD61.What is the name of the longest river in the world?A. AmazonB. NileC. YangtzeD. MississippiB62.The _____ (马戏团) has clowns.63.My grandma has a ________ (花园) full of ________ (蔬菜) like tomatoes and carrots.64.We have _______ (homework) to do.65.The ______ is known for her contributions to literature.66.iceberg) is a floating mass of ice. The ____67. A goldfish can recognize its ________________ (主人).68.The dolphin communicates with ______ (声音).69.What do we call a person who travels to different countries?A. TouristB. ExplorerC. TravelerD. All of the above70.What is the value of 10 5 + 3?A. 5B. 6C. 7D. 8B71.They are playing ___ (soccer/chess) outside.72.My _____ (宠物猫) loves to chase strings.73.Metals are usually ______ and can be shaped easily.74.What is the capital of Tanzania?A. DodomaB. Dar es SalaamC. ArushaD. MwanzaA75.The baby is _____ (sleeping/eating) in the crib.76.The chemical symbol for barium is _____.77.What is the capital of the Bahamas?A. NassauB. FreeportC. Marsh HarbourD. Andros TownA Nassau78.小猫) curls up in my lap. The ___79.Chemical reactions can be endothermic or ______.80.My friend is very ____.81. A lizard can change its ______.82.How many letters are in the word "elephant"?A. 6B. 7C. 8D. 9答案:B83.The jaguar is a _________ predator. (强大的)84.The ______ is very kind and helpful.85.The __________ mountains separate Europe and Asia. (乌拉尔山脉)86.What is the capital of Jamaica?A. KingstonB. Montego BayC. Ocho RiosD. MandevilleA Kingston87.What is the main ingredient in sushi?A. FishB. RiceC. SeaweedD. VegetablesB88.The dog is _______ (chasing) the ball.89.The __________ (历史的交织) fosters collaboration.90.Which instrument is used to measure temperature?A. BarometerB. ThermometerC. AltimeterD. Speedometer91.My favorite subject is _____ (math/science).92. A _____ (马) can carry heavy loads.93.The _______ can be very delicate.94.The country with the highest mountain is ________ (拥有最高山峰的国家是________).95.I enjoy _______ on a rainy day.96.The cake is ___ and sweet. (soft)97.What is the capital city of Greece?A. AthensB. RomeC. IstanbulD. CairoA Athens98. A chemical that resists changes in pH is a ______.99.My dog loves to play fetch with a ______ (球).100. A fulcrum is the point where a lever _______.。

《差别阈限原理》课件

心理测量学
差别阈限理论在心理测量学中用于评估个体的心理阈限和心理容量，为心理诊断和干预提供依据。
在生理学研究中的应用
生理反应研究
差别阈限理论在生理学研究中用于研究生物体的生理反应，如神经传导、肌肉收缩等。通过测量生理反应阈限的变化，可以了解生物体的生理功能和适应性。
药物反应研究
差别阈限理论在药物研究中用于评估药物对生物体的作用效果和剂量依赖性。通过研究不同药物浓度下生物体的生理反应，有助于发现药物的疗效和副作用。
04
差别阈限理论的应用
在心理学研究中的应用
01
感知觉研究
差别阈限理论被广泛应用于感知觉研究，如视觉、听觉和触觉等。通过
测量感觉阈限的变化，可以了解人类感知觉的敏感性和适应性。
02 03
认知过程研究
差别阈限理论在认知心理学中也有应用，例如在注意、记忆和思维等领域。通过研究不同刺激强度下个体认知反应的变化，有助于理解认知过程的机制。
计算方法
差别阈限可以通过双星法、星-空法等方法进行测量和计算。
阈下刺激与阈上刺激
阈下刺激
低于阈限的刺激，无法引起感觉。
阈上刺激
高于阈限的刺激，能够引起感觉。
感觉适应与感觉对比
感觉适应
由于持续的刺激作用，感觉系统的敏感度会逐渐下降的现象。
感觉对比
不同刺激作用于同一感觉通道时，会产生相互作用，从而影响对刺激的感知。
最小变化法
最小变化法是一种通过逐渐改变刺激强度来测量感觉阈限的方法
。
在最小变化法中，实验者以最小的步长逐渐增加或减少刺激强度，直到被试能够察觉到刺激变化
为止，记录下此时的变化量。
最小变化法的优点在于可以测量绝对阈限和差别阈限，适用于测量感觉阈限和差别阈限，尤其适用于测量微小刺激变化的情况。

CELL DIFFERENATION

CELL DIFFERENATION
cleavage
The fertilized egg undergoes a series of very rapid cycles consisting of DNA synthesis followed by cell divisions.
•
Cleavage,in which the single large egg cell subdivides by repeated mitosis into many smaller cells,without any change in total mass.
⑵luxury gene:which are active only in differentiated cells,such as,genes for hemoglobin keratin,and so forth.
原位杂交(in situ hybridization) 实验证明，分化的细胞存在着“闲置不用”的结构基因
Genes can be switched on and off, and the cells of the body differ not because they contain different genes but they express different genes.
⑴ housekeeping gene: required for the survival of all cell,such as ,genes coding for membrane proteins, ribosomal proteins and so forth.
(II) trans-acting factor
• Transcription factor: Term loosely applied to any protein required to initiate or regulate transcription in eucaryotes. Includes both gene regulatory proteins as well as the general transcription factors.

C-13 U.S.A.和加拿大 Omega 电子产品说明书

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liquid junction and pH range of ±2000 mV
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Differentiating 180° and 90° switching of ferroelectric domains with three-dimensional piezoresponse force microscopyA. Roelofs, U. Böttger, R. Waser, F. Schlaphof, S. Trogisch, and L. M. EngCitation: Applied Physics Letters 77, 3444 (2000); doi: 10.1063/1.1328049View online: /10.1063/1.1328049View Table of Contents: /content/aip/journal/apl/77/21?ver=pdfcovPublished by the AIP PublishingArticles you may be interested inPiezoresponse force microscopy studies on the domain structures and local switching behavior ofPb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystalsJ. Appl. Phys. 112, 052006 (2012); 10.1063/1.4745979Three dimensional piezoresponse force microscopy polarization difference mapsJ. Appl. Phys. 109, 074110 (2011); 10.1063/1.3560773Formation of 90° elastic domains during local 180° switching in epitaxial ferroelectric thin filmsAppl. Phys. Lett. 84, 254 (2004); 10.1063/1.1633970In situ observation of ferroelectric 90°-domain switching in epitaxial Pb(Zr,Ti)O 3 thin films by synchrotron x-ray diffractionAppl. Phys. Lett. 79, 2444 (2001); 10.1063/1.1406981Asymmetric nanoscale switching in ferroelectric thin films by scanning force microscopyAppl. Phys. Lett. 78, 2751 (2001); 10.1063/1.1366644Differentiating180°and90°switching of ferroelectric domains with three-dimensional piezoresponse force microscopyA.Roelofs,a)U.Bo¨ttger,and R.WaserInstitut fu¨r Werkstoffe der Elektrotechnik,RWTH Aachen,D-52056Aachen,GermanyF.Schlaphof,S.Trogisch,and L.M.EngInstitut fu¨r Angewandte Photophysik,Technische Universita¨t Dresden,D-01062Dresden,Germany͑Received10July2000;accepted for publication4October2000͒Three-dimensional͑3D͒piezoresponse force microscopy is applied in order to differentiate90°and 180°domain switching in PbTiO3͑PTO͒thinﬁlms.The3D domain conﬁguration is recorded both statically,revealing the surface crystallographic orientation of PTOﬁlms on the nanometer scale, and dynamically by simultaneously mapping the in-plane and out-of-plane hysteresis loops.We show that exclusively180°switching occurs,also switching only half of the grain volume.©2000 American Institute of Physics.͓S0003-6951͑00͒04647-7͔In the growingﬁeld of applications for ferroelectric thin ﬁlms it is of great importance to understand the switching behavior of thinﬁlms in the nanoscale regime.Since ferro-electricﬁlms deposited on Si/SiO2/Pt substrates are pre-dominantly polycrystalline,an integrated device will incor-porate only a few grains as its size drops to several100nm. For ferroelectric devices of a size larger than microns,the properties are deﬁned through the integral behavior of the grains.Although usingﬁlms consisting of grains with ran-dom crystallographic orientation,having a different size and a variable remanent polarization,different devices will al-ways show comparable performance characteristics.Never-theless,device downscaling needs control over theﬁlm growth in order to obtain a dense well-orientedﬁlm with constant grain size.Only then will the switching properties be comparable on the submicron scale͑e.g.,for data storage applications͒.To investigate nanoscale domain mapping and switch-ing,Piezoresponse force microscopy͑PFM͒is applied in or-der to monitor ferroelectric and topological properties of in-dividual grains along all the three dimensions x,y,and z.1,2 In contrast to conventional macroscopic electrical character-ization using extended top electrodes,PFM may be used to study ferroelectric thinﬁlms in the early growth stage where coverage of the substrate is not complete.Whereas extended top electrodes would be shorted making macroscopical elec-trical characterization impossible PFM may be applied both for inspection and manipulation of single grains.Polycrystalline PbTiO3͑PTO͒ﬁlms were deposited onto a Si/SiO2/TiO2/Pt substrate by the sol-gel method.3A lead acetate trihydrate based precursor solution4was spin-coated onto the substrate and dried for2min on a hot plate at 350°C.Crystallization was initiated by a rapid thermal an-nealing͑RTA͒process at700°C for30min,resulting in polycrystallineﬁlms having no predominant crystallographic orientation as proven by x-ray measurements.Nanoscaleﬁlm inspection was carried out using a modi-ﬁed scanning force microscope from ThermoMicroscopes™. Comparable experimental setups can be found elsewhere.5–7 Operation in the PFM mode allows simultaneous recording of at least three different features:sample topography,out-of-plane polarization͑OPP͒,and in-plane-polarization͑IPP͒along the x-scan direction.This is done by applying an ac voltage between the conducting p-doped silicon cantilever and an electrode on the backside of the sample.The ampli-tude of this imaging voltage is tuned well below the coercive voltage of the ferroelectric material,while the frequency is chosen far above the low-pass cutoff of the force microscope feedback loop.Because of the inverse piezoelectric effect the applied voltage results in local thickness and lateral vibra-tions of the ferroelectric sample due to out-of-plane and in-plane componets of polarization,respectively.This leads to corresponding oscillations of the cantilever͑bending in z and torsion along x direction͒which can be measured using con-ventional lock-in techniques.Thus,it is possible to deter-mine the projection of the polarization vector onto the x-z plane.Please note that a polarization along the y direction causes a small buckling of the cantilever leading to convo-lution with the piezoresponse signal along the z axis.Never-theless,careful calibration on single crystalline standard samples allows full disentangling.8More details on the do-main imaging method are described elsewhere.9,10 To verify the ferroelectric behavior of the PTOﬁlms, out-of-plane,and in-plane hysteresis loops were simulta-neously recorded͓see Figs.1͑a͒and1͑b͔͒.This was per-formed by adding a slow oscillating triangular-shaped switching voltage͑200mHz,16V PP)to the piezoresponse imaging voltage͑20kHz,2V pp)at the tip.Higher switching amplitudes led to losses in resolution caused by cantilever damage through high currentﬂow,melting the cantilever tip as conﬁrmed by SEM.Figure1depicts the hysteresis loops measured on two different grains:while Fig.1͑a͒shows a grain which is mostly polarized along the x-direction͑dots͒, Fig.1͑b͒illustrates the opposite case with the polarization mostly in the z direction͑triangles͒.Both the OPP and IPP hysteresis was recorded simultaneously for each grain.Figure2shows that all examined grains displayed ferro-electric behavior.Since both OPP and IPP information wasa͒Author to whom correspondence should be addressed;electronic mail:roelofs@iwe.rwth-aachen.deAPPLIED PHYSICS LETTERS VOLUME77,NUMBER2120NOVEMBER2000recorded ͓Figs.2͑a ͒and 2͑b ͔͒it is possible to reconstruct the projection of the polarization into the x -z plane.It can be seen from Fig.2that the polarization distribution of the grains is arbitrary indicating random crystallographic orien-tation,as veriﬁed by x-ray ing additional information either by recording the IPP contribution in the y direction ͑rotating the sample by 90°͒to the polarization or by introducing a domain wall,it is possible to completely reconstruct the three-dimensional ͑3D ͒orientation of the po-larization within a single grain.11The ﬁrst approach was shown to be applicable for ferroelectric ceramics.8Here we chose the second possibility inducing domain walls by switching experiments.This also simpliﬁes the experimental procedure,since no sample rotation is needed.To induce switching,a dc voltage is applied between cantilever and platinum bottom electrode.One issue that becomes apparent upon switching deals with the question of the direction along which the polariza-tion will reorient.Theoretically switching angles of both 90°and 180°might be possible in ferroelectrics.12–14Knowing the polarization orientation in the x -z plane it is possible to distinguish between 90°and 180°switching.Figures 2͑c ͒and 2͑d ͒show a grain after applying a 10V pulse to the tip for 1s at the position indicated by the cross ͑X ͒.Only the upper half of the grain did switch showing a clear change in both the OPP and IPP signals.The ﬁgure shows that the cross is positioned well inside this upper half explaining the observed domain rearranging.The domain wall is aligned along the x direction,which proves that 180°switching occurred.If 90°domain switch-ing had taken place creating a 90°domain wall,the polariza-tion would be manifested in a head-to-tail conﬁguration and the vectors should be aligned under 45°with respect to the domain wall.As shown in Figs.2͑c ͒and 2͑d ͒we measure a symmetric change both in the OPP and IPP signal from bright to dark ͑not to gray ͒,which means that only the sign changes while the amplitude remains constant.Therefore,the supposed 90°domain wall should be within the x -z plane ͑perpendicular to the sample surface ͒.For any otherorienta-FIG.1.In-plane and out-of-plane nanoscale hysteresis loops recorded by PFM for two different grain orientations.Triangles ͑᭝͒and dots ͑᭹͒show the OPP and IPP signal,respectively.While grain ͑a ͒is partly polarized in-plane,grain ͑b ͒shows mostly polarization along the z direction,having no measurable in-plane loop.Note that the four curves are displayed in equal relativestrength.FIG.2.PFM top view illustrations of the PTO thin ﬁlm showing the spatial distribution of OPP ͑a ͒,͑c ͒and IPP ͑b ͒,͑d ͒.Note the domain switching in ͑c ͒,͑d ͒after applying a 10V pulse to the tip at position ͑X ͒.tion of the 90°domain wall the absolute value of the OPP and IPP signals would have changed,because due to 90°switching the polarization direction should rotate,e.g.,from the z to the y direction showing a change from maximum OPP signal to zero OPP signal ͓compare with the similar case in Fig.3͑d ͔͒.Furthermore,a 90°domain wall in the x -z plane would mean a large polarization pointing along the y axis.Thus for that speciﬁc grain,both the OPP and IPP signal should be lower compared with other grains having their polarization fully in the x -z plane.Nevertheless,the grain shows a strong contrast before and after switching for both the z -and y -axis signal ͓Figs.2͑c ͒and 2͑d ͔͒,comparable to the grains with the highest measured contrast in Figs.2͑a ͒and 2͑b ͒.There-fore 90°switching can be ruled out.The results can only be interpreted as 180°switching.The polarization is parallel to the domain wall,completely within the x -z plane.Figure 3schematically depicts our experimental situa-tion.The spontaneous polarization of the observed grain is oriented within the x -z plane.This leads to a strong piezo-response signal both in-plane and out-of-plane ͓indicated by the bright color in Fig.3͑a ͔͒.More precisely the polarization vector points in the ͓Ϫx ,Ϫz ͔direction.In the case of 180°switching ͓Fig.3͑b ͔͒both the OPP and IPP signal will be inverted ͑symmetrical to zero ͒.Therefore the phase of the OPP and IPP signal is observed to jump by 180°͑as was shown in Fig.2͒.In the case of 90°switching two eventualities may be discussed.First the polarization might remain in the x -zplane and only the out-of-plane signal changes contrast,keeping the in-plane contrast constant ͓Fig.3͑c ͔͒.This indi-cates 90°domain switching from ͓Ϫx ,Ϫz ͔to ͓Ϫx ,ϩz ͔.The second possibility sketched in Fig.3͑d ͒shows the switching from ͓Ϫx ,Ϫz ͔direction into the y axes.Here both the OPP and IPP contrast will change from bright to gray,which represents the zero signal.Nevertheless,none of these 90°switching processes were ever observed,even when the experiment was repeated on various grains.Of course the experimental case discussed above may be special in that we have speciﬁcally selected a grain where the polarization points parallel to the x -z plane.For polarization vectors pointing along the y axis the differentiation between 90°and 180°switching will be far more complicated if not impossible due to the measuring setup.Nevertheless,since the PTO grains show a random distribution in polarization,the reported result is general and therefore applicable to the whole PTO ﬁlm.In conclusion,we demonstrated that PTO thin ﬁlms show true ferroelectric behavior,measuring both the in-plane and out-of-plane hysteresis loops.Furthermore,we are able to determine the three-dimensional polarization distribution of individual grains within the PTO ﬁlm,enabling us to dif-ferentiate between 180°and 90°ferroelectric domain switch-ing.We showed that only 180°switching occurred in all measurements.Additionally,grains were found to have no predominant orientation of polarization.1L.M.Eng,F.Schlaphof,S.Trogisch,A.Roelofs,and R.Waser,Ferro-electrics ͑to be published ͒.2L.M.Eng,F.Schlaphof,S.Trogisch,A.Roelofs,and R.Waser,Integr.Ferroelectr.͑to be published ͒.3D.Bolten,M.Hoffmann,U.Hasenkox,O.Lohse,and R.Waser,Ferro-electrics 225,117͑1999͒.4D.J.Wouters,G.J.Norga,and H.E.Maes,Mater.Res.Soc.Symp.Proc.541,381͑1999͒.5K.Franke,J.Besold,W.Haessler,and C.Seegebarth,Surf.Sci.Lett.302,L283͑1994͒.6T.Hidaka,T.Maruyama,I.Sakai,M.Saitoh,L.A.Wills,R.Hiskes,S.A.Dicarolis,J.Amano,and C.M.Foster,Integr.Ferroelectr.17,319͑1997͒.7O.Auciello,A.Gruvermann,H.Tokumoto,S.A.Prekash,S.Aggerwal,and R.Ramesh,MRS Bull.23,33͑1998͒.8L.M.Eng,H.J.Gu¨ntherodt,G.A.Schneider,U.Ko ¨pke,and J.Mun ˜oz Saldan ˜a,Appl.Phys.Lett.74,233͑1999͒.9M.Abplanalp,L.M.Eng,and P.Gu ¨nter,Appl.Phys.A:Mater.Sci.Process.66,S231͑1998͒.10L.M.Eng,M.Abplanalp,and P.Gu ¨nter,Appl.Phys.A:Mater.Sci.Process.66,S679͑1998͒.11G.Arlt and P.Sasko,J.Appl.Phys.51,4956͑1980͒.12E.Fatuzzo and W.J.Merz,Ferroelectricity ͑North-Holland,Amsterdam,1967͒,p.197ff.13W.Merz,Phys.Rev.95,690͑1954͒.14J.Fousek and B.Brezina,Czech.J.Phys.,Sect.B 10,511͑1960͒.FIG.3.Schematic representation of individual grain switching displayed in OPP ͑top row ͒and IPP ͑middle row ͒signals.Note the change from initial ͑a ͒to 180°switched ͑b ͒and the two possibilities in 90°switching ͑c ͒,͑d ͒.The bottom row shows the effective distribution of polarization vectors in each state.。