1988_[Aperture Coupled]_Aperture coupled Patch Antennas with Wide band
InSAR 系列讲座1 合成孔径雷达遥感新技术_InSAR介绍
© 1994-2010 China Academic Journal Electronic Publishing House. All rights reserved.
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单天线重复轨道干涉系统 。如图 1 “地面部分”所 示 , 机载/ 星载雷达系统基于侧视成像几何获取初 数据 , 然后须经计算机集焦 (focusing) 和滤波处理 以形成 SAR 影像 , 也就是说 , 合成孔径的概念是通
随后的技术扩展结果是差分雷达干涉 , 用以探 测地 球 表 面 的 微 小 形 变 。1989 年 , NASA/ J PL 的 Gabriel 等首次提出卫星差分雷达干涉的观点并发表 了对 California 某地区地面垂直位移观测的实验结 果 ; 1993 年 , 法国 CNES 的 Massonnet 等基于卫星差 分雷达干涉成功地测量了 1992 年 California Landers 地震引起的显著地表位移 。这些早期的研究结果 , 极大地鼓舞与推动了 InSAR 技术的快速向前发展 。 近年来 , 国际上众多学者在 InSAR 的硬件系统优
Abstract : As a new and promising technology of microwave remote sensing , synthetic aperture radar interferometry ( InSAR) is currently under rapidly developing stage. In order to make numerous surveyors comprehend InSAR , a tutorial with six sepa2 rate parts will be prepared and shown in the journal. As the first part of the tutorial , the paper will in general introduce the developing history , technological backgrounds , system components and applications of InSAR. Key words : InSAR ; developing history ; system components , applications
Internal wave study in the South China Sea using Synthetic Aperture
Internal wave study in the South China Sea using Synthetic Aperture Radar (SAR)A.K.LIU*{and M.K.HSU {{Oceans and Ice Branch,NASA Goddard Space Flight Center,Greenbelt,Maryland 20771,USA{Department of Oceanography,National Taiwan Ocean University,Keelung,TaiwanAbstract.Internal wave distribution maps have been compiled from more thanone hundred ERS-1/2,RADARSAT and Space Shuttle SAR images in the SouthChina Sea (SCS)from 1993to 2000.Based on these distribution maps,most of theinternal waves in the north-east part of the SCS were propagating westward.Thewave crest can be as long as 200km with an amplitude of 100m,due to strongcurrent from the Kuroshio branching out into the SCS.In a recent SCS internalwave study,moorings were deployed in April 1999and 2000.Simultaneous SARcoverage from ERS-2and RADARSAT were also collected.The ERS-2high-resolution SAR images collected from the Taiwan ground station were processed innear real-time to coordinate the field test.SAR data are then used to compare withmooring data.SAR data and Acoustic Doppler Current Profiler (ADCP)data showinternal solitons induced by the semi-diurnal tides with a wave speed of 2.4m s 21.1.IntroductionIt has been demonstrated that surface signatures of these nonlinear internal waves are observable in the Synthetic Aperture Radar (SAR)images from Russian Almaz-1and from the First and Second European Remote sensing Satellite ERS-1/2(Liang et al .1995).Furthermore,many interesting internal waves and related processes have been studied using SAR images in the East and South China Seas (ESC and SCS)and the Yellow Sea,such as upwelling,Kuroshio meandering,fronts,pollution,ship wakes and internal waves (Liu et al .1998).Field tests have been planned by the US Office of Naval Research (ONR)’s Asian Seas Interna-tional Acoustics Experiment (ASIAEX)and this joint experiment by the USA,Russia,Japan,Korea,Singapore,Taiwan and China was conducted in the East and South China Seas in the year 2001.These field experiments provide a unique opportunity to study the evolution of nonlinear internal waves and to validate SAR-observed internal wave signatures in the East and South China Seas.2.Nonlinear internal waves in the South China SeaThe Kuroshio moving north from the Philippine Basin branches out near the south tip of Taiwan and part of the Kuroshio intrudes into the South China Sea through the Bashi Channel and the Luzon Strait.The surface signature of huge internal wave packets has been observed in the ERS-1SAR images (Liu et al .,1998)from the South China Sea.The crest of the soliton is more than 200km long and eachInternational Journal of Remote SensingISSN 0143-1161print/ISSN 1366-5901online #2004Taylor &Francis Ltd/journalsDOI:10.1080/01431160310001592148An updated version of a paper originally presented at Oceans from Space ‘Venice 2000’Symposium ,Venice,Italy,9–13October 2000.*e-mail:antony.a.liu@INT .J .REMOTE SENSING ,10–20APRIL ,2004,VOL .25,NO .7–8,1261–1264packet contains more than ten rank-ordered solitons with a packet width of25km. Within a wave packet,the wavelengths appear to be monotonically decreasing,front to rear,from5km to500m.These are the biggest internal waves ever observed in this area. The internal wave amplitude is larger than100m,based on the Conductivity,Tem-perature and Depth system(CTD)casts.These huge wave packets propagate and evolve into the South China Sea andfinally reach the continental shelf of southern China.The effects of water depth on the evolution of solitons have been modelled by Kortweg-deVries(KdV)-type equation(Liu,1988)and linked to satellite image observations.The internal wave distribution map in the north-east part of the SCS has been compiled from hundreds of ERS-1/2,RADARSAT and space shuttle SAR images from1993to1999by Hsu et al.(2000)and an updated map with full coverage of the SCS is shown infigure1.Based on the internal wave distribution map,most of the internal waves in the north-east part of the South China Sea are propagating westward.From the observations at drilling rigs near DongSha Island by Amoco Production Co.,most of the solitons may be generated in a wide channel between Batan and Sabtang islands in the Luzon Strait.The sill between Batan and Sabtang islands is like a saddle point.The proposed generation mechanism is similar to the lee wave formation from shallow topography in the Sulu Sea(Apel et al.1985;Liu et al.1985).However,the internal waves near Hainan Island and Taiwan are generated from the shelf break.The disturbance of the mixed area of the pycnocline is then driven by the semi-diurnal tide and evolves into a rank-ordered wave packet.3.Recent SAR observationsIn a recent South China Sea internal wave study,as part of the ASIAEX program,five moorings were deployed in April2000.The moorings consisted of a chain of thermistors and ADCP.Simultaneous SAR coverages from ERS-2and RADARSAT were collected and processed.The ERS-2high-resolution(with25m resolution)SAR images collected from the Taiwan ground station were processed in near real-time (two hours).As an example,figure2shows an ERS-2SAR image(100km6100km) of huge internal solitons collected on26April,2000north of DongSha Island in the SCS.The crest of the solitons is longer than200km,with an amplitude of more than 100m.Based on mooring data,the maximum current in the mixed layer was about2m s21in a westerly direction,and was more than1m s21in an easterly directioninFigure1.Bathymetry and internal wave distribution map in the South China Sea. 1262 A.K.Liu and M.K.Hsuthe bottom layer which is typically induced by a mode-one wave.In four hours,the SAR images were interpreted and a delineated map was then transferred to the ocean research ship in the SCS by fax.Based on the satellite information,the chief scientist on board can then make a decision to coordinate the survey strategy,if needed.Based on the SAR images and hydrographic data,internal waves of elevation were identified in shallow water due to a thicker mixed layer as compared with the bottom layer on the continental shelf.Both depression and elevation internal waves have been observed in the same Radarsat ScanSAR image on May 4,1998near DongSha Island (Hsu and Liu 2000).Figure 3shows a subscene (200km 6300km)of a RADARSAT image (with 100m resolution),collected on 22April,2000,of internal solitons near DongSha Island with crests more than 200km long and awave speed of 2.4m s 21.The white dot in the image is DongSha Island and is located at longitude 116‡42E and latitude 20‡56N.There are at least four internal wave packets on this subscene propagating and passing the DongSha Island and its surrounding coral reefs.The distance between the packets on the left and right of the island is ca 80km,as shown in figure 3.The depression internal waves (in the first three wave packets from the right)changed their polarity after passing through a ‘turning point’and became elevation internal wave packets (in the wave packet atthe upper left corner of the image)in the shallow water.The critical depth at turning point is where mixed layer depth equals bottom layer thickness.Each depression wave is characterized by a bright band followed immediately by a dark band,and the elevation wave has a reversed pattern (a dark band followed immediately by a bright band).The separation time between these three wave packets is approximately two semi-diurnal tidal cycles,i.e.25hours.As demonstrated by the numerical simulation,the depression internal waves from the deep ocean propagate onto the shelf,and will convert to elevation waves in the shallow water after 20hours (Liu et al .,1998)which is consistent with thisSAR Figure 2.ERS-2SAR image of huge internal solitons collected on 26April 2000nearDongsha Island in the South China Sea.The geographical coordinates of four corners are shown in the image as NE,NW,SW and SE.Venice 2000–Oceans from Space 1263observation.Notice that the distance between the third depression wave packet and elevation wave packet is only 37km,which is wave retardation caused by the bottom friction and dissipation to slow down the wave speed in the shallow water.This preliminary survey from the year 2000helped considerably in the planning for the major field experiment in May 2001.AcknowledgmentsThe authors would like to thank the Canadian Space Agency for providing RADARSAT images.The ERS-2SAR images provided by the European Space Agency (ESA)are also acknowledged.This research was supported by the National Aeronautics &Space Administration and the Office of Naval Research.ReferencesA PEL ,J.R.,H OLBROOK ,J.R.,L IU ,A.K.,and T SAI ,J.,1985,The Sulu Sea internal solitonexperiment.Journal of Physical Oceanography ,15,1625–1651.H SU ,M.K.,and L IU ,A.K.,2000,Nonlinear internal waves in the South China Sea.Canadian Journal of Remote Sensing ,26,72–81.H SU ,M.K.,L IU ,A.K.,and L IU ,C.,2000,A study of internal waves in the China Seas andYellow Sea using SAR.Continental Shelf Research ,20,389–410.L IANG ,N.K.,L IU ,A.K.,and P ENG ,C.Y.,1995,A preliminary study of SAR imagery onTaiwan coastal water.Acta Oceanography Taiwanica ,34,17–28.L IU ,A.K.,1988,Analysis of nonlinear internal waves in the New York Bight.Journal ofGeophysical Research ,93,12317–12329.L IU ,A.K.,A PEL ,J.R.,and H OLBROOK ,J.R.,1985,Nonlinear internal wave evolution inthe Sulu Sea.Journal of Physical Oceanography ,15,1613–1624.L IU ,A.K.,C HANG ,Y.S.,H SU ,M.K.,and L IANG ,N.K.,1998,Evolution of nonlinearinternal waves in the East and South China Seas.Journal of Geophysical Research ,103,7995–8008.Figure 3.Subscene of RADARSAT image (200km 6300km)collected on 22April 2000.There are at least four internal wave packets propagated toward and passed the DongSha Island (the white dot)and coral reefs.The white dot in the image is DongSha Island and is located at longitude 116‡42E and latitude 20‡56N.The depression internal waves (the first three wave packets from the right)changed their polarity after passing through a ‘turning point’and became elevation internal wave packet (the wave packet at the upper left corner)in the shallow water.1264Venice 2000–Oceans from Space。
两体系统在旋转磁场中的Berry相解读
两体系统在旋转磁场中的Berry相自从1984年Berry提出绝热近似下的几何相问题，这个领域吸引了大批研究者。
他们讨论了几何相的理论基础、应用前景和实验验证。
本论文关注于这样一个模型：两个定域电子在旋转磁场中，它们不仅受到磁场对它们的作用，而且要受到电子和电子之间的相互作用。
磁感应强度B|-的方向随时间周期性变化，但保持它的模不变，也就是B|-张开一个S~2的光滑微分流形。
我们考虑B|-做周期运动，即在S~2上会形成一个闭合曲线。
经过大量计算，我们找出了两个有解析解的模型，而本论文主要讨论这两个模型。
首先计算在同一个磁场中电子和电子之间的相互作用为XXX模型的Berry相。
经过分析，可以发现有两个瞬时本征态的Berry相精确为零，而不为零的瞬时本征态的Berry相只受到了参数θ的影响，并且电子之间的相互作用系数对其没有影响。
我们还找到了Berry相和z方向Pauli矩阵平均值之间的关系。
其次我们用微扰论的方法讨论两电子在完全相同的旋转磁场中的Berry相，并且考虑电子之间的相互作用为XXZ的模型。
另外我们发现Berry相不仅受到了参数θ的影响，而且我们还可以看到，与XXX模型不同的是，电子之间的相互作用系数x_J和z_J会影响Berry相。
类似于XXX模型，在此模型中，我们也找到了Berry相和z方向Pauli矩阵平均值之间的关系。
同主题文章[1].张忠灿,方祯云,胡陈果,孙世军. Berry几何相与量子跃迁' [J]. 高能物理与核物理. 2000.(12)[2].蒋占峰,李润东,刘伍明. 室温下无耗散的量子自旋流' [J]. 物理. 2005.(04)[3].黄昆. 无辐射跃迁的绝热近似和静态耦合理论' [J]. 中国科学A辑. 1980.(10)[4].肖青,孙昌璞. 高阶量子绝热近似方法和Berry相因子的性质' [J]. 东北师大学报(自然科学版). 1993.(01)[5].胡岗,丁达夫. 利用随机共振系统获取高信噪比' [J]. 北京师范大学学报(自然科学版). 1992.(03)[6].郑国桐,陈炽庆,裘志洪. 用_Λ~(238)U超核聚变检验裂变机制的可行性探讨' [J]. 计算物理. 1988.(04)[7].郭淑梅. 强磁场中氢原子波函数的研究' [J]. 辽宁师专学报(自然科学版). 2008.(04)[8].章兴国,李星文. 绝热近似方程对Ising模型的应用' [J]. 河北大学学报(自然科学版). 1986.(04)[9].潘学玲,李毓成. 强磁场中氢分子离子H_2~+ 的电子能级' [J]. 应用基础与工程科学学报. 1998.(03)[10].惠萍. 异核氢分子离子HD~+在磁场中的哈密顿量' [J]. 广东教育学院学报. 2006.(03)【关键词相关文档搜索】：理论物理; 绝热近似; Berry相; 两粒子系统; 旋转磁场; XXX模型; XXZ模型【作者相关信息搜索】：天津大学;理论物理;杜九林;杨大宝;。
低频活动漂浮潜水船声探测系统（LFATS）说明书
LOW-FREQUENCY ACTIVE TOWED SONAR (LFATS)LFATS is a full-feature, long-range,low-frequency variable depth sonarDeveloped for active sonar operation against modern dieselelectric submarines, LFATS has demonstrated consistent detection performance in shallow and deep water. LFATS also provides a passive mode and includes a full set of passive tools and features.COMPACT SIZELFATS is a small, lightweight, air-transportable, ruggedized system designed specifically for easy installation on small vessels. CONFIGURABLELFATS can operate in a stand-alone configuration or be easily integrated into the ship’s combat system.TACTICAL BISTATIC AND MULTISTATIC CAPABILITYA robust infrastructure permits interoperability with the HELRAS helicopter dipping sonar and all key sonobuoys.HIGHLY MANEUVERABLEOwn-ship noise reduction processing algorithms, coupled with compact twin line receivers, enable short-scope towing for efficient maneuvering, fast deployment and unencumbered operation in shallow water.COMPACT WINCH AND HANDLING SYSTEMAn ultrastable structure assures safe, reliable operation in heavy seas and permits manual or console-controlled deployment, retrieval and depth-keeping. FULL 360° COVERAGEA dual parallel array configuration and advanced signal processing achieve instantaneous, unambiguous left/right target discrimination.SPACE-SAVING TRANSMITTERTOW-BODY CONFIGURATIONInnovative technology achievesomnidirectional, large aperture acousticperformance in a compact, sleek tow-body assembly.REVERBERATION SUPRESSIONThe unique transmitter design enablesforward, aft, port and starboarddirectional transmission. This capabilitydiverts energy concentration away fromshorelines and landmasses, minimizingreverb and optimizing target detection.SONAR PERFORMANCE PREDICTIONA key ingredient to mission planning,LFATS computes and displays systemdetection capability based on modeled ormeasured environmental data.Key Features>Wide-area search>Target detection, localization andclassification>T racking and attack>Embedded trainingSonar Processing>Active processing: State-of-the-art signal processing offers acomprehensive range of single- andmulti-pulse, FM and CW processingfor detection and tracking. Targetdetection, localization andclassification>P assive processing: LFATS featuresfull 100-to-2,000 Hz continuouswideband coverage. Broadband,DEMON and narrowband analyzers,torpedo alert and extendedtracking functions constitute asuite of passive tools to track andanalyze targets.>Playback mode: Playback isseamlessly integrated intopassive and active operation,enabling postanalysis of pre-recorded mission data and is a keycomponent to operator training.>Built-in test: Power-up, continuousbackground and operator-initiatedtest modes combine to boostsystem availability and accelerateoperational readiness.UNIQUE EXTENSION/RETRACTIONMECHANISM TRANSFORMS COMPACTTOW-BODY CONFIGURATION TO ALARGE-APERTURE MULTIDIRECTIONALTRANSMITTERDISPLAYS AND OPERATOR INTERFACES>State-of-the-art workstation-based operator machineinterface: Trackball, point-and-click control, pull-down menu function and parameter selection allows easy access to key information. >Displays: A strategic balance of multifunction displays,built on a modern OpenGL framework, offer flexible search, classification and geographic formats. Ground-stabilized, high-resolution color monitors capture details in the real-time processed sonar data. > B uilt-in operator aids: To simplify operation, LFATS provides recommended mode/parameter settings, automated range-of-day estimation and data history recall. >COTS hardware: LFATS incorporates a modular, expandable open architecture to accommodate future technology.L3Harrissellsht_LFATS© 2022 L3Harris Technologies, Inc. | 09/2022NON-EXPORT CONTROLLED - These item(s)/data have been reviewed in accordance with the InternationalTraffic in Arms Regulations (ITAR), 22 CFR part 120.33, and the Export Administration Regulations (EAR), 15 CFR 734(3)(b)(3), and may be released without export restrictions.L3Harris Technologies is an agile global aerospace and defense technology innovator, delivering end-to-endsolutions that meet customers’ mission-critical needs. The company provides advanced defense and commercial technologies across air, land, sea, space and cyber domains.t 818 367 0111 | f 818 364 2491 *******************WINCH AND HANDLINGSYSTEMSHIP ELECTRONICSTOWED SUBSYSTEMSONAR OPERATORCONSOLETRANSMIT POWERAMPLIFIER 1025 W. NASA Boulevard Melbourne, FL 32919SPECIFICATIONSOperating Modes Active, passive, test, playback, multi-staticSource Level 219 dB Omnidirectional, 222 dB Sector Steered Projector Elements 16 in 4 stavesTransmission Omnidirectional or by sector Operating Depth 15-to-300 m Survival Speed 30 knotsSize Winch & Handling Subsystem:180 in. x 138 in. x 84 in.(4.5 m x 3.5 m x 2.2 m)Sonar Operator Console:60 in. x 26 in. x 68 in.(1.52 m x 0.66 m x 1.73 m)Transmit Power Amplifier:42 in. x 28 in. x 68 in.(1.07 m x 0.71 m x 1.73 m)Weight Winch & Handling: 3,954 kg (8,717 lb.)Towed Subsystem: 678 kg (1,495 lb.)Ship Electronics: 928 kg (2,045 lb.)Platforms Frigates, corvettes, small patrol boats Receive ArrayConfiguration: Twin-lineNumber of channels: 48 per lineLength: 26.5 m (86.9 ft.)Array directivity: >18 dB @ 1,380 HzLFATS PROCESSINGActiveActive Band 1,200-to-1,00 HzProcessing CW, FM, wavetrain, multi-pulse matched filtering Pulse Lengths Range-dependent, .039 to 10 sec. max.FM Bandwidth 50, 100 and 300 HzTracking 20 auto and operator-initiated Displays PPI, bearing range, Doppler range, FM A-scan, geographic overlayRange Scale5, 10, 20, 40, and 80 kyd PassivePassive Band Continuous 100-to-2,000 HzProcessing Broadband, narrowband, ALI, DEMON and tracking Displays BTR, BFI, NALI, DEMON and LOFAR Tracking 20 auto and operator-initiatedCommonOwn-ship noise reduction, doppler nullification, directional audio。
A Theory for Multiresolution Signal Decomposition The Wavelet ...
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Manuscript received July 30. 1987: revised December 23. 1988. This work was supported under the following Contracts and Grants: NSF grant IODCR-84 1077 1. Air Force Grant AFOSR F49620-85-K-0018. Army DAAG-29-84-K-0061. NSF-CERiDC82-19196 Ao2. and DARPAiONR ARPA N0014-85-K-0807. The author is with the Department of Computer Science Courant Institute of Mathematical Sciences. New York University. New York, NY 10012. IEEE Log Number 8928052.
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IEEE TRANSACTIONS PATTERN ON ANALYSISAND MACHINE INTELLIGENCE.VOL. II, NO. 7. JULY 1%')
A Theory for Multiresolution Signal Decomposition: The Wavelet Representation
STEPHANE Gsolution representations are very effective for analyzing the information content of images. We study the properties of the operator which approximates a signal at a given resolution. We show that the difference of information between the approximation of a signal at the resolutions 2’ + ’ and 2jcan be extracted by decomposing this signal on a wavelet orthonormal basis of L*(R”). In LL(R ), a wavelet orthonormal basis is a family of functions ( @ w (2’ ~ n)) ,,,“jEZt, which is built by dilating and translating a unique function t+r(xl. This decomposition defines an orthogonal multiresolution representation called a wavelet representation. It is computed with a pyramidal algorithm based on convolutions with quadrature mirror lilters. For images, the wavelet representation differentiates several spatial orientations. We study the application of this representation to data compression in image coding, texture discrimination and fractal analysis. Index Terms-Coding, fractals, multiresolution pyramids, ture mirror filters, texture discrimination, wavelet transform. quadra-
1-2007_-_Y_F_Han_-_PreparationofnanosizedMn3O4SBA15catalystforcomplet[retrieved-2016-11-15]
![1-2007_-_Y_F_Han_-_PreparationofnanosizedMn3O4SBA15catalystforcomplet[retrieved-2016-11-15]](https://img.taocdn.com/s3/m/9d89122483c4bb4cf7ecd13a.png)
Preparation of nanosized Mn 3O 4/SBA-15catalyst for complete oxidation of low concentration EtOH in aqueous solution with H 2O 2Yi-Fan Han *,Fengxi Chen,Kanaparthi Ramesh,Ziyi Zhong,Effendi Widjaja,Luwei ChenInstitute of Chemical and Engineering Sciences,1Pesek Road,Jurong Island 627833,Singapore Received 11May 2006;received in revised form 18December 2006;accepted 29May 2007Available online 2June 2007AbstractA new heterogeneous Fenton-like system consisting of nano-composite Mn 3O 4/SBA-15catalyst has been developed for the complete oxidation of low concentration ethanol (100ppm)by H 2O 2in aqueous solution.A novel preparation method has been developed to synthesize nanoparticles of Mn 3O 4by thermolysis of manganese (II)acetylacetonate on SBA-15.Mn 3O 4/SBA-15was characterized by various techniques like TEM,XRD,Raman spectroscopy and N 2adsorption isotherms.TEM images demonstrate that Mn 3O 4nanocrystals located mainly inside the SBA-15pores.The reaction rate for ethanol oxidation can be strongly affected by several factors,including reaction temperature,pH value,catalyst/solution ratio and concentration of ethanol.A plausible reaction mechanism has been proposed in order to explain the kinetic data.The rate for the reaction is supposed to associate with the concentration of intermediates (radicals: OH,O 2Àand HO 2)that are derived from the decomposition of H 2O 2during reaction.The complete oxidation of ethanol can be remarkably improved only under the circumstances:(i)the intermediates are stabilized,such as stronger acidic conditions and high temperature or (ii)scavenging those radicals is reduced,such as less amount of catalyst and high concentration of reactant.Nevertheless,the reactivity of the presented catalytic system is still lower comparing to the conventional homogenous Fenton process,Fe 2+/H 2O 2.A possible reason is that the concentration of intermediates in the latter is relatively high.#2007Elsevier B.V .All rights reserved.Keywords:Hydrogen peroxide;Fenton catalyst;Complete oxidation of ethanol;Mn 3O 4/SBA-151.IntroductionRemediation of wastewater containing organic constitutes is of great importance because organic substances,such as benzene,phenol and other alcohols may impose toxic effects on human and animal anic effluents from pharmaceu-tical,chemical and petrochemical industry usually contaminate water system by dissolving into groundwater.Up to date,several processes have been developed for treating wastewater that contains toxic organic compounds,such as wet oxidation with or without solid catalysts [1–4],biological oxidation,supercritical oxidation and adsorption [5,6],etc.Among them,catalytic oxidation is a promising alternative,since it avoids the problem of the adsorbent regeneration in the adsorption process,decreases significantly the temperature and pressure in non-catalytic oxidation techniques [7].Generally,the disposalof wastewater containing low concentration organic pollutants (e.g.<100ppm)can be more costly through all aforementioned processes.Thus,catalytic oxidation found to be the most economical way for this purpose with considering its low cost and high efficiency.Currently,a Fenton reagent that consists of homogenous iron ions (Fe 2+)and hydrogen peroxide (H 2O 2)is an effective oxidant and widely applied for treating industrial effluents,especially at low concentrations in the range of 10À2to 10À3M organic compounds [8].However,several problems raised by the homogenous Fenton system are still unsolved,e.g.disposing the iron-containing waste sludge,limiting the pH range (2.0–5.0)of the aqueous solution,and importantly irreversible loss of activity of the reagent.To overcome these drawbacks raised from the homogenous Fenton system,since 1995,a heterogeneous Fenton reagent using metal ions exchanged zeolites,i.e.Fe/ZSM-5has proved to be an interesting alternative catalytic system for treating wastewater,and showed a comparable activity with the homogenous Fenton system [9].However,most reported heterogeneous Fenton reagents still need UV radiation during/locate/apcatbApplied Catalysis B:Environmental 76(2007)227–234*Corresponding author.Tel.:+6567963806.E-mail address:han_yi_fan@.sg (Y .-F.Han).0926-3373/$–see front matter #2007Elsevier B.V .All rights reserved.doi:10.1016/j.apcatb.2007.05.031oxidation of organic compounds.This might limit the application of homogeneous Fenton system.Exploring other heterogeneous catalytic system considering the above disadvantages,is still desirable for this purpose.Here,we present an alternative catalytic system for the complete oxidation of organic com-pounds in aqueous solution using supported manganese oxide as catalyst under mild conditions,which has rarely been addressed.Mn-containing oxide catalysts have been found to be very active for the catalytic wet oxidation of organic effluents (CWO)[10–14],which is operated at high air pressures(1–22MPa)and at high temperatures(423–643K)[15].On the other hand,manganese oxide,e.g.MnO2[16],is well known to be active for the decomposition of H2O2in aqueous solution to produce hydroxyl radical( OH),which is considered to be the most robust oxidant so far.The organic constitutes can be deeply oxidized by those radicals rapidly[17].The only by-product is H2O from decomposing H2O2.Therefore,H2O2is a suitable oxidant for treating the wastewater containing organic compounds.Due to the recent progress in the synthesis of H2O2 directly from H2and O2[18,19],H2O2is believed to be produced through more economical process in the coming future.So,the heterogeneous Fenton system is economically acceptable.In this study,nano-crystalline Mn3O4highly dispersed inside the mesoporous silica,SBA-15,has been prepared by thermolysis of organic manganese(II)acetylacetonate in air. We expect the unique mesoporous structure may provide add-itional function(confinement effect)to the catalytic reaction, i.e.occluding/entrapping large organic molecules inside pores. The catalyst as prepared has been examined for the complete oxidation of ethanol in aqueous solution with H2O2,or to say, wet peroxide oxidation.Ethanol was selected as a model organic compound because(i)it is one of the simplest organic compounds and can be easily analyzed,(ii)it has high solu-bility in water due to its strong hydrogen bond with water molecule and(iii)the structure of ethanol is quite stable and only changed through catalytic reaction.Presently,for thefirst time by using the Mn3O4/SBA-15catalyst,we investigated the peroxide ethanol oxidation affected by factors such as temperature,pH value,ratio of catalyst(g)and volume of solution(L),and concentration of ethanol in aqueous solution. In addition,plausible reaction mechanisms are established to explain the peroxidation of ethanol determined by the H2O2 decomposition.2.Experimental2.1.Preparation and characterization of Mn3O4/SBA-15 catalystSynthesis of SBA-15is similar to the previous reported method[20]by using Pluronic P123(BASF)surfactant as template and tetraethyl orthosilicate(TEOS,98%)as silica source.Manganese(II)acetylacetonate([CH3COCH C(O)CH3]2Mn,Aldrich)by a ratio of2.5mmol/gram(SBA-15)werefirst dissolved in acetone(C.P.)at room temperature, corresponding to ca.13wt.%of Mn3O4with respect to SBA-15.The preparation method in detail can be seen in our recent publications[21,22].X-ray diffraction profiles were obtained with a Bruker D8 diffractometer using Cu K a radiation(l=1.540589A˚).The diffraction pattern was taken in the Bragg angle(2u)range at low angles from0.68to58and at high angles from308to608at room temperature.The XRD patterns were obtained by scanning overnight with a step size:0.028per step,8s per step.The dispersive Raman microscope employed in this study was a JY Horiba LabRAM HR equipped with three laser sources(UV,visible and NIR),a confocal microscope,and a liquid nitrogen cooled charge-coupled device(CCD)multi-channel detector(256pixelsÂ1024pixels).The visible 514.5nm argon ion laser was selected to excite the Raman scattering.The laser power from the source is around20MW, but when it reached the samples,the laser output was reduced to around6–7MW after passing throughfiltering optics and microscope objective.A100Âobjective lens was used and the acquisition time for each Raman spectrum was approximately 60–120s depending on the sample.The Raman shift range acquired was in the range of50–1200cmÀ1with spectral resolution1.7–2cmÀ1.Adsorption and desorption isotherms were collected on Autosorb-6at77K.Prior to the measurement,all samples were degassed at573K until a stable vacuum of ca.5m Torr was reached.The pore size distribution curves were calculated from the adsorption branch using Barrett–Joyner–Halenda(BJH) method.The specific surface area was assessed using the BET method from adsorption data in a relative pressure range from 0.06to0.10.The total pore volume,V t,was assessed from the adsorbed amount of nitrogen at a relative pressure of0.99by converting it to the corresponding volume of liquid adsorbate. The conversion factor between the volume of gas and liquid adsorbate is0.0,015,468for N2at77K when they are expressed in cm3/g and cm3STP/g,respectively.The measurements of transmission electron microscopy (TEM)were performed at Tecnai TF20S-twin with Lorentz Lens.The samples were ultrasonically dispersed in ethanol solvent,and then dried over a carbon grid.2.2.Kinetic measurement and analysisThe experiment for the wet peroxide oxidation of ethanol was carried out in a glass batch reactor connected to a condenser with continuous stirring(400rpm).Typically,20ml of aqueous ethanol solution(initial concentration of ethanol: 100ppm)wasfirst taken in the round bottomflask(reactor) together with5mg of catalyst,corresponding to ca.1(g Mn)/30 (L)ratio of catalyst/solution.Then,1ml of30%H2O2solution was introduced into the reactor at different time intervals (0.5ml at$0min,0.25ml at32min and0.25ml at62min). The total molar ratio of H2O2/ethanol is about400/1. Hydrochloric acid(HCl,0.01M)was used to acidify the solution if necessary.NH4OH(0.1M)solution was used to adjust pH to9.0when investigating the effect of pH.The pH for the deionized water is ca.7.0(Oakton pH meter)and decreased to 6.7after adding ethanol.All the measurements wereY.-F.Han et al./Applied Catalysis B:Environmental76(2007)227–234 228performed under the similar conditions described above if without any special mention.For comparison,the reaction was also carried out with a typical homogenous Fenton reagent[17], FeSO4(5ppm)–H2O2,under the similar reaction conditions.The conversion of ethanol during reaction was detected using gas chromatography(GC:Agilent Technologies,6890N), equipped with HP-5capillary column connecting to a thermal conductive detector(TCD).There is no other species but ethanol determined in the reaction system as evidenced by the GC–MS. Ethanol is supposed to be completely oxidized into CO2and H2O.The variation of H2O2concentration during reaction was analyzed colorimetrically using a UV–vis spectrophotometer (Epp2000,StellarNet Inc.)after complexation with a TiOSO4/ H2SO4reagent[18].Note that there was almost no measurable leaching of Mn ion during reaction analyzed by ICP(Vista-Mpx, Varian).3.Results and discussion3.1.Characterization of Mn3O4/SBA-15catalystThe structure of as-synthesized Mn3O4inside SBA-15has beenfirst investigated with powder XRD(PXRD),and the profiles are shown in Fig.1.The profile at low angles(Fig.1a) suggests that SBA-15still has a high degree of hexagonal mesoscopic organization even after forming Mn3O4nanocrys-tals[23].Several peaks at high angles of XRD(Fig.1b)indicate the formation of a well-crystallized Mn3O4.All the major diffraction peaks can be assigned to hausmannite Mn3O4 structure(JCPDS80-0382).By N2adsorption measurements shown in Fig.2,the pore volume and specific surface areas(S BET)decrease from 1.27cm3/g and937m2/g for bare SBA-15to0.49cm3/g and 299m2/g for the Mn3O4/SBA-15,respectively.About7.7nm of mesoporous diameter for SBA-15decreases to ca.6.3nm for Mn3O4/SBA-15.The decrease of the mesopore dimension suggests the uniform coating of Mn3O4on the inner walls of SBA-15.This nano-composite was further characterized by TEM. Obviously,the SBA-15employed has typical p6mm hex-agonal morphology with the well-ordered1D array(Fig.3a). The average pore size of SBA-15is ca.8.0nm,which is very close to the value(ca.7.7nm)determined by N2adsorption. Along[001]orientation,Fig.3b shows that the some pores arefilled with Mn3O4nanocrystals.From the pore A to D marked in Fig.3b correspond to the pores from empty to partially and fullyfilled;while the features for the SBA-15 nanostructure remains even after forming Mn3O4nanocrys-tals.Nevertheless,further evidences for the location of Mn3O4inside the SBA-15channels are still undergoing in our group.Raman spectra obtained for Mn3O4/SBA-15is presented in Fig.4a.For comparison the Raman spectrum was also recorded for the bulk Mn3O4(97.0%,Aldrich)under the similar conditions(Fig.4b).For the bulk Mn3O4,the bands at310,365, 472and655cmÀ1correspond to the bending modes of Mn3O4, asymmetric stretch of Mn–O–Mn,symmetric stretch of Mn3O4Fig.1.XRD patterns of the bare SBA-15and the Mn3O4/SBA-15nano-composite catalyst.(a)At low angles:(A)Mn3O4/SBA-15,(B)SBA-15;and (b)at high angles of Mn3O4/SBA-15.Fig.2.N2adsorption–desorption isotherms:(!)SBA-15,(~)Mn3O4/SBA-15.Y.-F.Han et al./Applied Catalysis B:Environmental76(2007)227–234229groups,respectively [24–26].However,a downward shift ($D n 7cm À1)of the peaks accompanying with a broadening of the bands was observed for Mn 3O 4/SBA-15.For instance,the distinct feature at 655cm À1for the bulk Mn 3O 4shifted to 648cm À1for the nanocrystals.The Raman bands broadened and shifted were observed for the nanocrystals due to the effect of phonon confinement as suggested previously in the literature [27,28].Furthermore,a weak band at 940cm À1,which should associate with the stretch of terminal Mn O,is an indicative of the existence of the isolated Mn 3O 4group [26].The assignment of this unique band has been discussed in our previous publication [22].3.2.Kinetic study3.2.1.Blank testsUnder a typical reaction conditions,that is,20ml of 100ppm ethanol aqueous solution (pH 6.7)mixed with 1ml of 30%H 2O 2,at 343K,there is no conversion of ethanol was observed after running for 120min in the absence of catalyst or in the presence of bare SBA-15(5mg).Also,under the similar conditions in H 2O 2-free solution,ethanol was not converted for all blank tests even with Mn 3O 4/SBA-15catalyst (5mg)in the reactor.It suggests that a trace amount of oxygen dissolved in water or potential dissociation of adsorbed ethanol does not have any contribution to the conversion of ethanol under reaction conditions.To study the effect of low temperature evaporation of ethanol during reaction,we further examined the concentration of ethanol (100ppm)versus time at different temperatures in the absence of catalyst and H 2O 2.Loss of ca.5%ethanol was observed only at 363K after running for 120min.Hence,to avoid the loss of ethanol through evaporation at high temperatures,which may lead to a higher conversion of ethanol than the real value,the kinetic experiments in this study were performed at or below 343K.The results from blank tests confirm clearly that ethanol can be transformed only by catalytic oxidation during reaction.3.2.2.Effect of amount of catalystThe effect of amount of catalyst on ethanol oxidation is presented in Fig.5.Different amounts of catalyst ranging from 2to 10mg were taken for the same concentration of ethanol (100ppm)in aqueous solution under the standard conditions.It can be observed that the conversion of ethanol increases monotonically within 120min,reaching 15,20and 12%for 2,5and 10mg catalysts,respectively.On the other hand,Fig.5shows that the relative reaction rates (30min)decreased from 0.7to ca 0.1mmol/g Mn min with the rise of catalyst amount from 2to 10mg.Apparently,more catalyst in the system may decrease the rate for ethanol peroxidation,and a proper ratio of catalyst (g)/solution (L)is required for acquiring a balance between the overall conversion of ethanol and reaction rate.In order to investigate the effects from other factors,5mg (catalyst)/20ml (solution),corresponding to 1(g Mn )/30(L)ratio of catalyst/solution,has been selected for the followedexperiments.Fig.4.Raman spectroscopy of the Mn 3O 4/SBA-15(a)and bulk Mn 3O 4(b).Fig.3.TEM images recorded along the [001]of SBA-15(a),Mn 3O 4/SBA-15(b):pore A unfilled with hexagonal structure,pores B and C partially filled and pore D completely filled.Y.-F .Han et al./Applied Catalysis B:Environmental 76(2007)227–2342303.2.3.Effect of temperatureAs shown in Fig.6,the reaction rate increases with increasing the reaction temperature.After 120min,the conversion of ethanol increases from 12.5to 20%when varying the temp-erature from 298to 343K.Further increasing the temperature was not performed in order to avoid the loss of ethanol by evaporation.Interestingly,the relative reaction rate increased with time within initial 60min at 298and 313K,but upward tendency was observed above 333K.3.2.4.Effect of pHIn the pH range from 2.0to 9.0,as illustrated in Fig.7,the reaction rate drops down with the rise of pH.It indicates that acidic environment,or to say,proton concentration ([H +])in the solution is essential for this reaction.With considering our target for this study:purifying water,pH approaching to 7.0in the reaction system is preferred.Because acidifying the solution with organic/inorganic acids may potentially causea second time pollution and result in surplus cost.Actually,there is almost no effect on ethanol conversion with changing pH from 5.5to 6.7in this system.It is really a merit comparing with the conventional homogenous Fenton system,by which the catalyst works only in the pH range of 2.0–5.0.3.2.5.Effect of ethanol concentrationThe investigation of the effect of ethanol concentration on the reaction rate was carried out in the ethanol ranging from 50to 500ppm.The results in Fig.8show that the relative reaction rate increased from 0.07to 2.37mmol/g Mn min after 120min with increasing the concentration of ethanol from 50to 500ppm.It is worth to note that the pH value of the solution slightly decreased from 6.7to 6.5when raising the ethanol concentration from 100to 500ppm.paring to a typical homogenous Fenton reagent For comparison,under the similar reaction conditions ethanol oxidation was performed using aconventionalFig.5.The ethanol oxidation as a function of time with different amount of catalyst.Conversion of ethanol vs.time (solid line)on 2mg (&),5mg (*)and 10mg (~)Mn 3O 4/SBA-15catalyst,the relative reaction rate vs.time (dash line)on 2mg (&),5mg (*)and 10mg (~)Mn 3O 4/SBA-15catalyst.Rest conditions:20ml of ethanol (100ppm),1ml of 30%H 2O 2,708C and pH of6.7.Fig.6.The ethanol oxidation as a function of temperature.Conversion of ethanol vs.time (solid line)at 258C (&),408C (*),608C (~)and 708C (!),the relative reaction rate vs.time (dash line)at 258C (&),408C (*),608C (~)and 708C (5).Rest conditions:20ml of ethanol (100ppm),1ml of 30%H 2O 2,pH of 6.7,5mg ofcatalyst.Fig.7.The ethanol oxidation as a function of pH value.Conversion of ethanol vs.time (solid line)at pH value of 2.0(&),3.5(*),4.5(~),5.5(!),6.7(^)and 9.0("),the relative reaction rate vs.time (dash line)at pH value of 2.0(&),3.5(*),4.5(~),5.5(5),6.7(^)and 9.0(").Rest conditions:20ml of ethanol (100ppm),1ml of 30%H 2O 2,708C,5mg ofcatalyst.Fig.8.The ethanol oxidation as a function of ethanol concentration.Conver-sion of ethanol vs.time (solid line)for ethanol concentration (ppm)of 50(&),100(*),300(~),500(!),the relative reaction rate vs.time (dash line)for ethanol concentration (ppm)of 50(&),100(*),300(~),500(5).Condi-tions:20ml of ethanol,pH of 6.7,1ml of 30%H 2O 2,708C,5mg of catalyst.Y.-F .Han et al./Applied Catalysis B:Environmental 76(2007)227–234231homogenous reagent,Fe 2+(5ppm)–H 2O 2(1ml)at pH of 5.0.It has been reported to be an optimum condition for this system [17].As shown in Fig.9,the reaction in both catalytic systems exhibits a similar behavior,that is,the conversion of ethanol increases with extending the reaction time.Varying reaction temperature from 298to 343K seems not to impact the conversion of ethanol when using the homogenous Fenton reagent.Furthermore,the conversion of ethanol (defining at 120min)in the system of Mn 3O 4/SBA-15–H 2O 2is about 60%of that obtained from the conventional Fenton reagent.There are no other organic compounds observed in the reaction mixture other than ethanol suggesting that ethanol directly decomposing to CO 2and H 2O.3.2.7.Decomposition of H 2O 2In the aqueous solution,the capability of metal ions such as Fe 2+and Mn 2+has long been evidenced to be effective on the decomposition of H 2O 2to produce the hydroxyl radical ( OH),which is oxidant for the complete oxidation/degrading of organic compounds [9,17].Therefore,ethanol oxidation is supposed to be associated with H 2O 2decomposition.The investigation of H 2O 2decomposition has been performed under the reaction conditions (in an ethanol-free solution)with different amounts of catalyst.H 2O 2was introduced into the reaction system by three steps,initially 0.5ml followed by twice 0.25ml at 32and 62min,the pH of 6.7is set for all experiments except pH of 5.0for Fe 2+.As shown in Fig.10,H 2O 2was not converted in the absence of catalyst or presence of bare SBA-15(5mg);in contrast,by using the Mn 3O 4/SBA-15catalyst we observed that ca.Ninety percent of total H 2O 2was decomposed in the whole experiment.It can be concluded that that dissociation of H 2O 2is mainly caused by Mn 3O paratively,the rate of H 2O 2decomposition is relatively low with the homogenous Fenton reagent,total conversion of H 2O 2,was ca.50%after runningfor 120min.Considering the fact that H 2O 2decomposition can be significantly enhanced with the rise of Fe 2+concentration,however,it seems not to have the influence on the reaction rate for ethanol oxidation simultaneously.The similar behavior of H 2O 2decomposition was also observed during ethanol oxidation.The rate for ethanol oxidation is lower for Mn 3O 4/SBA-15comparing to the conventional Fenton reagent.The possible reasons will be discussed in the proceeding section.3.3.Plausible reaction mechanism for ethanol oxidation with H 2O 2In general,the wet peroxide oxidation of organic constitutes has been suggested to proceed via four steps [15]:activation of H 2O 2to produce OH,oxidation of organic compounds withOH,recombination of OH to form O 2and wet oxidation of organic compounds with O 2.It can be further described by Eqs.(1)–(4):H 2O 2À!Catalyst =temperture 2OH(1)OH þorganic compoundsÀ!Temperatureproduct(2)2 OHÀ!Temperature 12O 2þH 2O(3)O 2þorganic compoundsÀ!Temperature =pressureproduct(4)The reactive intermediates produced from step 1(Eq.(1))participate in the oxidation through step 2(Eq.(2)).In fact,several kinds of radical including OH,perhydroxyl radicals ( HO 2)and superoxide anions (O 2À)may be created during reaction.Previous studies [29–33]suggested that the process for producing radicals could be expressed by Eqs.(5)–(7)when H 2O 2was catalytically decomposed by metal ions,such asFeparison of ethanol oxidation in systems of typical homogenous Fenton catalyst (5ppm of Fe 2+,20ml of ethanol (100ppm),1ml of 30%H 2O 2,pH of 5.0acidified with HCl)at room temperature (~)and 708C (!),and Mn 3O 4/SBA-15catalyst (&)under conditions of 20ml of ethanol (100ppm),pH of 6.7,1ml of 30%H 2O 2,708C,5mg ofcatalyst.Fig.10.An investigation of H 2O 2decomposition under different conditions.One milliliter of 30%H 2O 2was dropped into the 20ml deionized water by three intervals,initial 0.5ml followed by twice 0.25ml at 32and 62min.H 2O 2concentration vs.time:by calculation (&),without catalyst (*),SBA-15(~),5ppm of Fe 2+(!)and Mn 3O 4/SBA-15(^).Rest conditions:5mg of solid catalyst,pH of 7.0(5.0for Fe 2+),708C.Y.-F .Han et al./Applied Catalysis B:Environmental 76(2007)227–234232and Mn,S þH 2O 2!S þþOH Àþ OH (5)S þþH 2O 2!S þ HO 2þH þ(6)H 2O $H þþO 2À(7)where S and S +represent reduced and oxidized metal ions,both the HO 2and O 2Àare not stable and react further with H 2O 2to form OH through Eqs.(8)and (9):HO 2þH 2O 2! OH þH 2O þO 2(8)O 2ÀþH 2O 2! OH þOH ÀþO 2(9)Presently, OH radical has been suggested to be the main intermediate responsible for oxidation/degradation of organic compounds.Therefore,the rate for ethanol oxidation in the studied system is supposed to be dependent on the concentra-tion of OH.Note that the oxidation may proceed via step four (Eq.(4))in the presence of high pressure O 2,which is so-called ‘‘wet oxidation’’and usually occurs at air pressures (1–22MPa)and at high temperatures (423–643K)[15].However,it is unlikely to happen in the present reaction conditions.According to Wolfenden’s study [34],we envisaged that the complete oxidation of ethanol may proceed through a route like Eq.(10):C 2H 5OH þ OH À!ÀH 2OC 2H 4O À! OHCO 2þH 2O(10)Whereby,it is believed that organic radicals containing hydroxy-groups a and b to carbon radicals centre can eliminate water to form oxidizing species.With the degrading of organic intermediates step by step as the way described in Eq.(10),the final products should be CO 2and H 2O.However,no other species but ethanol was detected by GC and GC–MS in the present study possibly due to the rapid of the reaction that leads to unstable intermediate.Fig.5indicates that a proper ratio of catalyst/solution is a necessary factor to attain the high conversion of ethanol.It can be understood that over exposure of H 2O 2to catalyst will increase the rate of H 2O 2decomposition;but on the other hand,more OH radical produced may be scavenged by catalyst with increasing the amount of catalyst and transformed into O 2and H 2O as expressed in Eq.(3),instead of participating the oxidation reaction.In terms of Eq.(10),stoichiometric ethanol/H 2O 2should be 1/6for the complete oxidation of ethanol;however,in the present system the total molar ratio is 1/400.In other words,most intermediates were extinguished through scavenging during reaction.This may explain well that the decrease of reaction rate with the rise of ratio of catalyst/solution in the system.The same reason may also explain the decrease of reaction rate with prolonging the time.Actually,H 2O 2decomposition (ca.90%)may be completed within a few minutes over the Mn 3O 4/SBA-15catalyst as illustrated in Fig.10,irrespective of amount of catalyst (not shown for the sake of brevity);in contrast,the rate for H 2O 2decomposition became dawdling for Fe 2+catalyst.As a result,presumably,the homogenous system has relatively high concentration ofradicals.It may explain the superior reactivity of the conventional Fenton reagent to the presented system as depicted in Fig.9.Therefore,how to reduce scavenging,especially in the heterogeneous Fenton system [29],is crucial for enhancing the reaction rate.C 2H 5OH þ6H 2O 2!2CO 2þ9H 2O(11)On the other hand,as illustrated by Eqs.(1)–(4),all steps in the oxidation process are affected by the reaction temperature.Fig.6demonstrates that increasing temperature remarkably boosts the reactivity of ethanol oxidation in the system of Mn 3O 4/SBA-15–H 2O 2possibly,due to the improvement of the reactions in Eqs.(2)and (4)at elevated temperatures.In terms of Eqs.(6)and (7),acidic conditions may delay the H 2O 2decomposition but enhance the formation of OH (Eqs.(5),(8)and (9)).This ‘‘delay’’is supposed to reduce the chance of the scavenging of radicals and improve the efficiency of H 2O 2in the reaction.The protons are believed to have capability for stabilizing H 2O 2,which has been elucidated well previously [18,19].Consequently,it is understandable that the reaction is favored in the strong acidic environment.Fig.7shows a maximum reactivity at pH of 2.0and the lowest at pH of 9.0.As depicted in Fig.8,the reaction rate for ethanol oxidation is proportional to the concentration of ethanol in the range of 50–500ppm.It suggests that at low concentration of ethanol (100ppm)most of the radicals might not take part in the reaction before scavenged by catalyst.With increasing the ethanol concentration,the possibility of the collision between ethanol and radicals can be increased significantly.As a result,the rate of scavenging radicals is reduced relatively.Thus,it is reasonable for the faster rate observed at higher concentration of ethanol.Finally,it is noteworthy that as compared to the bulk Mn 3O 4(Aldrich,98.0%of purity),the reactivity of the nano-crystalline Mn 3O 4on SBA-15is increased by factor of 20under the same typical reaction conditions.Obviously,Mn 3O 4nanocrystal is an effective alternative for this catalytic system.The present study has evidenced that the unique structure of SBA-15can act as a special ‘‘nanoreactor’’for synthesizing Mn 3O 4nanocrystals.Interestingly,a latest study has revealed that iron oxide nanoparticles could be immobilized on alumina coated SBA-15,which also showed excellent performance as a Fenton catalyst [35].However,the role of the pore structure of SBA-15in this reaction is still unclear.We do expect that during reaction SBA-15may have additional function to trap larger organic molecules by adsorption.Thus,it may broaden its application in this field.So,relevant study on the structure of nano-composites of various MnO x and its role in the Fenton-like reaction for remediation of organic compounds in aqueous solution is undergoing in our group.4.ConclusionsIn the present study,we have addressed a new catalytic system suitable for remediation of trivial organic compound from contaminated water through a Fenton-like reaction withY.-F .Han et al./Applied Catalysis B:Environmental 76(2007)227–234233。
Aperture Coupled Cavity Backed Patch Antenna
专利名称：Aperture Coupled Cavity Backed PatchAntenna发明人：James C. Carson,James K. Tillery,Sara Phillips申请号：US10091186申请日：20020304公开号：US06897809B2公开日：20050524专利内容由知识产权出版社提供专利附图：摘要：A compact antenna system can generate RF radiation fields having increased beamwidths and bandwidths. The antenna system can include one or more patchradiators. The lower patch radiators can be mounted to a printed circuit board that caninclude a ground plane which defines a plurality of slots. The slots within the ground plane of the printed circuit board can be excited by stubs that are part of the feed network of the printed circuit board. The slots, in turn, can establish RF radiation in a cavity which is disposed adjacent to the ground plane of the printed circuit board and a ground plane of the antenna system.申请人：James C. Carson,James K. Tillery,Sara Phillips地址：Sugar Hill GA US,Woodstock GA US,Norcross GA US国籍：US,US,US代理机构：King & Spalding LLP更多信息请下载全文后查看。
VARIABLE APERTURE MECHANISM FOR CREATING DIFFERENT
专利名称：VARIABLE APERTURE MECHANISM FOR CREATING DIFFERENT APERTURE SIZES INCAMERAS AND OTHER IMAGING DEVICES 发明人：BREST, Michael L.申请号：US2013/068649申请日：20131106公开号：WO2014/074553A1公开日：20140515专利内容由知识产权出版社提供专利附图：摘要：An apparatus includes a first blade (206) configured to be coupled to a first magnet (220) and a second blade (208) configured to be coupled to a second magnet(220). At least one of the blades has at least one cutout (214). The apparatus also includes electromagnetic motors (112a, 112b) configured to generate different electromagnetic fields to (i) cause the magnets to move the blades into a first configuration and (ii) cause the magnets to move the blades into a second configuration. The blades are separated to form a larger aperture in the first configuration, and the at least one cutout in the blades forms a smaller aperture in the second configuration. The apparatus may further include a cover plate (210) and a base plate (212). The base plate can include an opening that defines the larger aperture and blade stops (302) and stop pins (402) configured to stop movement of the blades.申请人：RAYTHEON COMPANY地址：02451-1449 US国籍：US代理人：LOVELESS, Ryan S. et al.更多信息请下载全文后查看。
Optical coupler and electronic equipment using sam
专利名称：Optical coupler and electronic equipmentusing same发明人：Nobuyuki Ohe,Kazuhito Nagura申请号：US11017914申请日：20041222公开号：US20050141584A1公开日：20050630专利内容由知识产权出版社提供专利附图：摘要：On one surface of a lead frame having an aperture passing through in thickness direction thereof, a submount having transparency for closing the aperture of the lead frame is disposed. On a surface of the submount opposite to a surface of the submountfacing the aperture of the lead frame , a semiconductor optical device is disposed in such a way that an optical portion thereof faces toward the aperture. The semiconductor optical device is electrically connected to the lead frame via wire . At least one surface of the lead frame , the semiconductor optical device and the submount are encapsulated with a molding portion made of a non-transparent molding resin in a state that the aperture on the other surface side of the lead frame is exposed.申请人：Nobuyuki Ohe,Kazuhito Nagura地址：Katsuragi-shi JP,Kashihara-shi JP国籍：JP,JP更多信息请下载全文后查看。
SYNTHETIC-APERTURE RADAR DEVICE
更多信息请下载全文后查看
专利内容由知Biblioteka 产权出版社提供专利名称：SYNTHETIC-APERTURE RADAR DEVICE 发明人：SHINOHARA HIROSHI 申请号：JP31982290 申请日：19901122 公开号：J P H 04 190186A 公开日：19920708
摘要：PURPOSE:To obtain three dimensional image in front of a flying body in real time by electronically switching the irradiation direction of the beam to the right and left of the flying body into both of range and azimuth directions. CONSTITUTION:In one cycle in each position of proceed of a flying body, a radar scans with an off-nadir angle of theta1 in the range direction for the first and second emission period on both sides of azimuth direction of proceeding direction using the beam width of theta, and scans with the angle of theta2 for the third and fourth period in the same way. An antenna 10 shifts 5 the phase of this signal input with a time series, converts each output signal of its T/R module to a synthetic signal 17 and an I/Q video signal 16, and a real time signal processor 11 performs compression processing of each of range and azimuth. Then, synthetic open radar image data 23 and 25 corresponding to the angles theta1 and theta2 are output in real time to a memory 12 and a stereo processor 13. The memory 12 outputs the image data 24 synchronized with the input to the processor 13. These data 24 and 25 are indicated 14 as a front three dimensional image data obtained by stereo processing 13.
LARGE-APERTURE TELEPHOTO LENS
专利名称：LARGE-APERTURE TELEPHOTO LENS 发明人：ARAI YASUNORI申请号：JP921482申请日：19820123公开号：JPS6132648B2公开日：19860728专利内容由知识产权出版社提供摘要：PURPOSE:To obtain a compact, large-aperture telephoto lens of FNo 1:1.8-2, view angle about 18 deg. that can maintain good aberration by constituting a lens system of 6 groups and 7 elements and satisfying specified formulas. CONSTITUTION:The first lens group consists of a positive lens, the second lens group consists of combined lens of a negative meniscus lens that faces its large curvature face (concave face) to the image side and a positive meniscus lens, the third lens group consists of a negative meniscus lens that faces the concave face to the image side, the fourth lens group consists of a meniscus lens that faces the concave face to the subject, the fifth lens group consists of a positive meniscus lens that faces large curvature face to the subject, and the sixth lens group consists of a positive lens, and they satisfy conditional formulas (1)-(5). Focussing is performed by fixing the sixth lens group and extending the first to fifth lens groups.申请人：ASAHI OPTICAL CO LTD更多信息请下载全文后查看。
合成孔径光学成像系统与图像复原技术
合成孔径光学成像系统与图像复原技术刘立涛,聂亮(西安工业大学光电工程学院，陕西西安710021)摘要:结合信息光学理论知识与合成孔径系统的基本成像原理，得出了三种类型子孔径排布方式下的光学调制传递函数(MTF)分布，分析其成像特性；利用MATLAB 软件在不同孔径排布情况下模拟其成像退化结果；采用最大似然的R--L 复原方法对成像结果分别进行复原。
根据计算机理论模拟的结果，该方法有较好的复原效果，图像的清晰度有所改善，一些细节系信息也有所完善；其中三臂型的清晰度最好，复原结果最佳。
关键词:合成孔径；点扩散函数；光学调制传递函数；退化；复原中图分类号：TP391.41文献标识码:A文章编号:1003-7241(2021)003-0096-06Synthetic Aperture Optical Imaging System and Image Restoration TechnologyLIU Li -tao,NIE Liang(School of Optoelectronic Engineering,Xi'an Technological University,Xi'an 710021China )Abstract:Based on the theoretical knowledge of information optics and the basic imaging principle of synthetic aperture system,theoptical modulation transfer function (MTF)distribution of three types of subaperture distribution is obtained,and its imag-ing characteristics are analyzed.MATLAB software was used to simulate the image degradation results under different ap-erture arrangement.The maximum likelihood R-L restoration method was used to recover the imaging results.According to the results of computer simulation,the method has a good recovery effect,the image clarity is improved,and some de-tails are also improved.The three -arm model has the best definition and recovery results.Key words:synthetic aperture;PSF;MTF;degradation;restoration收稿日期:2019-12-181引言随着现代科技技术的不断发展，人们对光学系统的成像分辨率要求也日益增高，特别是像航天观测，遥感监测，对光学系统的分辨率要求非常高。
阻抗匹配技术无法匹敌孔径调谐技术（ApertureTuning）
阻抗匹配技术无法匹敌孔径调谐技术（ApertureTuning）作者：Rashid Osmani & Lars Johnsson, Cavendish Kinetics 全球LTE智能手机的出货量、网络配置以及频谱分配如今迅猛增长，而3GPP电信标准组织也已为LTE标准分配超过40个频段。
随着用户数和通信量的负荷持续加重，诸如AT&T(美)和Verizon(美)的主要电信商开始采用LTE-Advanced 载波聚合(Carrier Aggregation)技术以提升网络的速度和容量。
3GPP现今已确定愈60种频带组合，其中包括频带内和频带间聚合。
正因如此，智能手机需要优化技术以适应持续增加的频谱分配方案和载波聚合的可能性。
对手机内的LTE射频而言，这意味着射频必须能够“调”这些频带当中的任何一个，而这进一步要求该天线需要在所有频带上保持高效率表现。
但是说得容易做得难，天线效率的设计远远难过设定要求。
在手机生产史的早期，天线是信号射频系统设计师最后考虑的问题。
早期手机体积大，数据率低，加上全球只有4个频带。
这些因素确保早期手机的高信号性能表现不成问题。
而快进到2015年，随着而大屏幕和大电池则成为主流，手机已经演进为精密的智能手机。
原设备制造商逐渐采用多种天线调谐技术以确保LTE在多频带上的信号表现。
图1：手机的演进及相应的天线效率LTE射频最关键的是射频前端(RFFE)，包括天线及模拟数据处理。
RFFE中的功率放大器，滤波器以及电源转化器经设计能够在50欧—天线馈端(天线和RFFE连接处)的目标阻抗—以最高效率运作。
天线馈端的天线阻抗取决于天线的类型。
而移动设备生产中应用最广泛的是双波段PIFA天线。
在谐振频率中，天线的馈电点阻抗为纯电阻(PIFA天线大约90Ω ，偶极子天线约72Ω ，而单极子天线约36 Ω ) 。
为了最大限度地提高辐射效率，利用简单的固定匹配电路能将天线的阻抗匹配为50 Ω，借此提高输入天线功率的辐射。