期刊文献+
共找到251篇文章
< 1 2 13 >
每页显示 20 50 100
Metal-organic framework-derived porous carbon for the advanced aqueous zinc-ion hybrid capacitor
1
作者 LIU Wei-fang HU Zi-han ZHANG Qi 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第7期2268-2279,共12页
Aqueous zinc ion hybrid capacitors(ZIHCs)are considered one of the most promising electrochemical energy storage systems due to their high safety,environmental friendliness,low cost,and high power density.However,the ... Aqueous zinc ion hybrid capacitors(ZIHCs)are considered one of the most promising electrochemical energy storage systems due to their high safety,environmental friendliness,low cost,and high power density.However,the low energy density and the lack of sustainable design strategies for the cathodes hinder the practical application of ZIHCs.Herein,we design the N and O co-doped porous carbon cathode by annealing metal-organic framework(ZIF-8).ZIF-8 retains the original dodecahedral structure with a high specific surface(2814.67 m^(2)/g)and I_(G)/I_(D) ratio of 1.0 during carbonization and achieves self-doping of N and O heteroatoms.Abundant defect sites are introduced into the porous carbon to provide additional active sites for ion adsorption after the activation of carbonized ZIF-8 by KOH treatment.The ZIHCs assembled with modified ZIF-8 as the cathode and commercial zinc foil as the anode show an energy density of 125 W∙h/kg and a power density of 79 W/kg.In addition,this ZIHCs device achieves capacity retention of 77.8%after 9000 electrochemical cycles,which is attributed to the diverse pore structure and plentiful defect sites of ZIF-8-800(KOH).The proposed strategy may be useful in developing high-performance metal-ion hybrid capacitors for large-scale energy storage. 展开更多
关键词 zinc ion hybrid capacitor CATHODE metal-organic framework(ZIF-8) KOH activation
下载PDF
Design,Analysis,and Optimization of a CMOS Active Pixel Sensor 被引量:2
2
作者 徐江涛 姚素英 +2 位作者 李斌桥 史再峰 高静 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2006年第9期1548-1551,共4页
A three-transistor active pixel sensor and its double sampling readout circuit implemented by a switch capacitor amplifier are designed. The circuit is embedded in a 64 × 64 pixel array CMOS image sensor and succ... A three-transistor active pixel sensor and its double sampling readout circuit implemented by a switch capacitor amplifier are designed. The circuit is embedded in a 64 × 64 pixel array CMOS image sensor and success-fully taped out with a Chartered 0.35μm process. The pixel pitch is 8μm × 8μm with a fill factor of 57%, the photo-sensitivity is 0.8V/(lux · s) ,and the dynamic range is 50dB. Theoretical analysis and test results indicate that as the process is scaled down, a smaller pixel pitch reduces the sensitivity. A deep junction n-well/p-substrate photodiode with a reasonable fill factor and high sensitivity are more appropriate for submicron processes. 展开更多
关键词 CMOS image sensor active pixel sensor fill factor photo-response sensitivity
下载PDF
FINITE ELEMENT MODELING OF MODERATELY THICK COMPOSITE PLATE WITH PIEZOELECTRIC SENSORS AND ACTUATORS 被引量:2
3
作者 周勇 王鑫伟 谈梅兰 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2003年第2期205-210,共6页
A rectangular finite element for laminated plate with bonded and/or embedded piezoelectric sensors and actuators is developed based on the variational principle and the first order shear deformation theory. The elemen... A rectangular finite element for laminated plate with bonded and/or embedded piezoelectric sensors and actuators is developed based on the variational principle and the first order shear deformation theory. The element has four-node, 20-degrees-of-freedom with one potential degree of freedom for each piezoelectric layer to represent the piezoelectric behavior. The higher order derivation of deflection is obtained by using the normal rotation expressions to take the effects of transverse shear deformation into considerations. The finite element can accurately simulate the deformation of both thin and moderately thick plates. A Fortran program is written and a number of benchmark tests are exercised to verify its effectiveness. Results are compared well with the existing data. The unbalanced composite with piezoelectric layers is then analyzed by using the model. Results show that the changes of the ratio between the thickness of positive angle layers and the negative angle layers have an effect on the deformation of the structure under the same electric loading. 展开更多
关键词 finite element COMPOSITE moderately thick plate PIEZOELECTRIC ACTUATOR SENSOR
下载PDF
Numerical Study of Optimization of Layer Thickness in Bilayer Organic Light-Emitting Diodes 被引量:3
4
作者 彭应全 张磊 张旭 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2003年第5期454-460,共7页
A numerical model for bilayer organic light-emitting diodes (OLEDs) is developed under the basis of trapped charge limited conduction.The dependences of the current density on the layer thickness,trap properties and c... A numerical model for bilayer organic light-emitting diodes (OLEDs) is developed under the basis of trapped charge limited conduction.The dependences of the current density on the layer thickness,trap properties and carrier mobility of the hole transport layer (HTL) and emission layer (EML) in bilayer OLEDs of the structure anode/HTL/EML/cathode are numerically investigated.It is found that,for given values of the total thickness of organic layers,reduced depth of trap,total density of trap,and carrier mobility of HTL as well as EML,there exists an optimal thickness ratio of HTL to EML,by which a maximal quantum efficiency can be achieved.Through optimization of the thickness ratio,an enhancement of current density and quantum efficiency of as much as two orders of magnitude can be obtained.The dependences of the optimal thickness ratio to the characteristic trap energy,total density of trap and carrier mobility are numerically analyzed. 展开更多
关键词 organic light-emitting diodes BILAYER OPTIMIZATION
下载PDF
叔多父簋銘“孫_=”釋讀斟議 被引量:1
5
作者 蔡一峰 《出土文献》 2016年第2期58-63,共6页
《殷周金文集成》[1](以下簡稱《集成》)4004—4006號著錄了三件西周晚期叔多父簋銘文,其中4005號有器、蓋兩套銘文(4005-1,4005-2),其餘兩件各一套,内容相同(見附圖)。據《商周金文總著錄表》(以下簡稱《著錄表》)及《商周青銅器銘文... 《殷周金文集成》[1](以下簡稱《集成》)4004—4006號著錄了三件西周晚期叔多父簋銘文,其中4005號有器、蓋兩套銘文(4005-1,4005-2),其餘兩件各一套,内容相同(見附圖)。據《商周金文總著錄表》(以下簡稱《著錄表》)及《商周青銅器銘文暨圖像集成》(以下簡稱《銘圖》)的著錄信息,4005。 展开更多
关键词 著錄 上海 青銅 有器 銘圖 銘文 博物
下载PDF
5Gb/s 0.25μm CMOS Limiting Amplifier
6
作者 胡艳 王志功 +1 位作者 冯军 熊明珍 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2003年第12期1250-1254,共5页
A limiting amplifier (LA) IC implemented in TSMC standard 0.25μm CMOS technology is described.Active inductor loads and direct-coupled technology are employed to increase the gain,broaden the bandwidth,reduce the pow... A limiting amplifier (LA) IC implemented in TSMC standard 0.25μm CMOS technology is described.Active inductor loads and direct-coupled technology are employed to increase the gain,broaden the bandwidth,reduce the power dissipation,and keep a tolerable noise performance.Under a 3.3V supply voltage,the LA core achieves a gain of 50-dB with a power consumption below 40mW.The measured input sensitivity of the amplifier is better than 5m V _ pp .It can operate at bit rates up to 7Gb/s with an rms jitter of 0.03 UI or less.The chip area is only 0.70mm×0.70mm.According to the measurement results,this IC is expected to work at the standard bit rate levels of 2.5,3.125,and 5Gb/s. 展开更多
关键词 limiting amplifier active inductor shunt peaking technique CMOS
下载PDF
Ridge Waveguide Electro-Optic Polymer Modulator with a New Kind of Corona Poled Crosslinkable Polyurethane 被引量:1
7
作者 杨晓红 杜云 +2 位作者 殷爱民 石志文 吴荣汉 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2001年第2期130-133,共4页
A polymer electro optic modulator has been fabricated with the functional layer acting as a kind of corona poled crosslinkable polyurethane. The three optical layers, namely waveguide, photolithography and oxygen are... A polymer electro optic modulator has been fabricated with the functional layer acting as a kind of corona poled crosslinkable polyurethane. The three optical layers, namely waveguide, photolithography and oxygen are fabricated by spin coating. With the Reactive Ion Etching method, the ridge of the waveguide is constructed. With light at 1 31μm being fiber coupled to waveguide, the mode and the modulation properties of these devices are demonstrated in a micron control system. 展开更多
关键词 MODULATOR polymer ridge waveguide
下载PDF
Distribution and Dissipation of Braking Power of Wet Multidisc Brake 被引量:1
8
作者 阎清东 宿新东 《Journal of Beijing Institute of Technology》 EI CAS 2000年第1期87-93,共7页
To study the distribution and dissipation of braking power of wet multidisc brake and determine thermal load and thermal flux distribution between mated discs, the concept of distributing brake power four times was pu... To study the distribution and dissipation of braking power of wet multidisc brake and determine thermal load and thermal flux distribution between mated discs, the concept of distributing brake power four times was put forward. The third and the fourth distribution of brake power were calculated by using finite element(FE) software ANSYS. The third and the fourth distribution of wet multidisc brake are mainly related to material characteristics of discs during emergency braking, while most of the braking power is carried off during continuous braking. Basis is provided for further analysis of disc failure and applicability of different friction materials. 展开更多
关键词 wet multidisc brake braking power finite element(FE) analysis
下载PDF
Improving Efficiency by Doping PtOEP into Spiro Light-Emitting Devices
9
作者 赵俊卿 乔士柱 +3 位作者 许福运 张宁玉 庞岩涛 陈莹 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2008年第3期418-422,共5页
To investigate effective means of improving the efficiency of organic light-emitting devices (OLEDs) by making full use of ,triplet emission, a phosphorescent material Pt (II) Octaethylporphine (PtOEP) is doped ... To investigate effective means of improving the efficiency of organic light-emitting devices (OLEDs) by making full use of ,triplet emission, a phosphorescent material Pt (II) Octaethylporphine (PtOEP) is doped into polymer host polyspirobifluorene (Spiro) to allow radiative recombination of triplet excitons. The current and brightness characteristics of the devices are tested and the electroluminescent spectra are described. Both fluorescence and phosphorescence are ob- served,and an obvious increase in external quantum efficiency is realized compared to undoped devices when different phosphorescent dopant concentrations are tried. Thus,the phosphorescent emission from triplet excited states might be an effective way to increase the efficiency of OLEDs when the concentration of the phosphorescent dopant is properiy controlled. 展开更多
关键词 external quantum efficiency TRIPLET organic light-emitting device
下载PDF
COMPARISON AND EVALUATION OF CURRENT REFERENCE GENERATION STRATEGIES FOR ACTIVE POWER FILTERS IN THREE-PHASE FOUR-WIRE SYSTEMS
10
作者 陈东华 郭涛 +1 位作者 谢少军 周波 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2005年第4期298-306,共9页
For three phase four-wire active power filters (APFs), several typical power theories and corresponding current reference generation strategies are induced, p-q, d-q, unify power factor (UPF) and instantaneous act... For three phase four-wire active power filters (APFs), several typical power theories and corresponding current reference generation strategies are induced, p-q, d-q, unify power factor (UPF) and instantaneous active current (IAC) methods are analyzed and compared with each other. The interpretation of active and reactive currents in non-sinusoidal and unbalanced three-phase four-wire systems is given based on the generalized instantaneous reactive power theory. The performance and the characteristic are evaluated, and the application conditions of current reference generation strategies are concluded. Simulation results under different source voltages and loads verify the evaluation result. 展开更多
关键词 active power filters instantaneous reactive power current reference three-phase four wire power
下载PDF
Effect of Flating Photobioreactor Light-path on the Growth and Organic Matter Accumulation of Isochrysis galbana Parke
11
作者 吴电云 邹宁 +1 位作者 高维锡 黄清荣 《Agricultural Science & Technology》 CAS 2010年第11期7-9,共3页
[Objective] The paper aims to provide references to cultivate I.galbana in a large scale and explore its medical value.[Method] I.galbana had been cultivated in different light-path flat plate bioreactors,and the grow... [Objective] The paper aims to provide references to cultivate I.galbana in a large scale and explore its medical value.[Method] I.galbana had been cultivated in different light-path flat plate bioreactors,and the growth condition and content of organic matter within cells of I.galbana had been analyzed.[Result] Growth rate and volumetric productivity of I.galbana cells increased as light-path of flat plate bioreactors decreased,however,daily areal output rate rose with the increasing of light path.The smaller the light path of flat plate bioreactors was,the more content of total lipids,protein and polysaccharide it had in I.galbana cells.[Conclusion] It is an effective way to improve production efficiently and reduce the cost by selecting the suitable bioreactors. 展开更多
关键词 Isochrysis galbana parke Light-path PHOTOBIOREACTOR PRODUCTIVITY Organic matter
下载PDF
Energy Transfer Probability Between Host and Guest in Doped Organic Electrophosphorescent Devices 被引量:1
12
作者 李宏建 欧阳俊 +3 位作者 代国章 戴小玉 潘艳芝 谢强 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2006年第4期674-678,共5页
An expression for energy transfer probability (η) between host (TPD) and guest (Ir(ppy)3) phosphorescent systems is proposed,and the energy transfer process in doped organic electrophosphorescent (EP) devic... An expression for energy transfer probability (η) between host (TPD) and guest (Ir(ppy)3) phosphorescent systems is proposed,and the energy transfer process in doped organic electrophosphorescent (EP) devices is discussed. The results show that (1) The rate of the triplet energy transfer (KHG and KGH) exponentially increases with the host-guest molecular distance (R), and KHG decreases quickly as the intermolecular distance of the guest (RGG) increases. In addition,the KHG/KGH ratio of the dopant system increases when R or RGG is reduced; (2) The energy transfer probability approximately linearly decreases as R increases from 0.8 to 1.2nm,and the variation of RGG can be neglected when R〈1.1nm. For 1. 1nm〈R〈l. 2nm, RGG (〈1.6nm) plays an increasingly important role when 71 drops with the latter' (3) η increases when the Forster energy transfer rate increases or Gibb's energy declines. 展开更多
关键词 ELECTROPHOSPHORESCENCE energy transfer probability TRIPLET
下载PDF
MATERIAL SURFACE THERMAL PROPERTY IDENTIFICATION USING HEAT FLUX TACTILE SENSOR
13
作者 吴剑锋 毛志鹏 +2 位作者 李建清 周连杰 蔡凤 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2012年第1期84-89,共6页
Eased on the mechanism of temperature tactile sensing of human finger,a heat flux tactile sensor com- posed of a thermostat module and a heat flux sensor is designed to identify material thermal properties. The ther- ... Eased on the mechanism of temperature tactile sensing of human finger,a heat flux tactile sensor com- posed of a thermostat module and a heat flux sensor is designed to identify material thermal properties. The ther- mostat module maintains the sensor temperature invariable, and the heat flux sensor(Peltier device) detects the heat flux temperature difference between the thermostat module and the object surface. Two different modes of the heat flux tactile sensor are proposed, and they are simulated and experimented for different material objects. The results indicate that the heat flux tactile sensor can effectively identify different thermal properties. 展开更多
关键词 heat flux tactile sensor heat flux material identification Peltier device ANSYS finite element method(FEM) simulation
下载PDF
OPTIMAL DESIGN OF DUAL STATOR-WINDING INDUCTION GENERATOR WITH PWM CONVERTER 被引量:2
14
作者 刘陵顺 胡育文 黄文新 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2006年第3期185-193,共9页
To minimize the reactive power of the converter of the control winding in the novel dual stator-winding induction generator based on the PWM converter, design features of the induction generator with a rectified load ... To minimize the reactive power of the converter of the control winding in the novel dual stator-winding induction generator based on the PWM converter, design features of the induction generator with a rectified load are proposed. The optimization method of excited capacitors to minimize the reactive power of the control winding at a variable speed is given. The calculation capacity of the machine with a diode bridge rectifier load is proposed. To achieve global searching, the integrated method with the improved real-coded genetic algorithm and the twodimensional finite element method (FEM) is introduced. Design results of the sample show that reactive power can be reduced by the method, and the converter capacity can be decreased to 1/3 of output rated power at the speed ratio of 1 : 3, thus reducing the volume and the mass of the inverter. 展开更多
关键词 dual stator-winding induction generator variable speed PWM converter genetic algorithm FEM optimal design
下载PDF
Advances in Small RNAs and Sexual Reproduction in Plants
15
作者 王俊 何桥 +5 位作者 汪卫星 向素琼 孙海艳 李晓林 梁国鲁 郭启高 《Agricultural Science & Technology》 CAS 2013年第2期211-214,229,共5页
Small RNAs are non-coding RNA molecules with 20-30 nucleotides (nt) in length that mainly play regulatory roles in gene expression at the post-transcription level by directly cutting target mRNA or inhibiting its tr... Small RNAs are non-coding RNA molecules with 20-30 nucleotides (nt) in length that mainly play regulatory roles in gene expression at the post-transcription level by directly cutting target mRNA or inhibiting its translation. Small RNAs play regulatory roles in the growth and development process of plants at the core of gene regulatory networks, which has been widely studied and confirmed in sporophyte generation of plants. However, few researches have been conducted on small RNAs and gametophyte generation. It is reported that small RNAs play important roles in floral organ development, gametogenesis, fertilization, and early zygotic development of plants. In addition, various small RNAs also play roles in controlling genetic integrity, cell differentiation and functions during the sexual reproduction process of plants. However, most of the specific functions of small RNAs in the sexual reproduction process are unknown yet. This study mainly aimed to introduce small RNAs in plants, summarize the latest advances in researches of small RNAs and plant sexual reproduction, and make prospect on its future. 展开更多
关键词 Small RNA Sexual reproduction Floral organ development GAMETOGENESIS FERTILIZATION Early zygotic development
下载PDF
Design and Implementation of an Optoelectronic Integrated Receiver in Standard CMOS Process 被引量:1
16
作者 余长亮 毛陆虹 +3 位作者 宋瑞良 朱浩波 王蕊 王倩 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2007年第8期1198-1203,共6页
A wideband monolithic optoelectronic integrated receiver with a high-speed photo-detector,completely compatible with standard CMOS processes,is designed and implemented in 0.6μm standard CMOS technology.The experimen... A wideband monolithic optoelectronic integrated receiver with a high-speed photo-detector,completely compatible with standard CMOS processes,is designed and implemented in 0.6μm standard CMOS technology.The experimental results demonstrate that its performance approaches applicable requirements,where the photo-detector achieves a -3dB frequency of 1.11GHz,and the receiver achieves a 3dB bandwidth of 733MHz and a sensitivity of -9dBm for λ=850nm at BER=10-12. 展开更多
关键词 PHOTO-DETECTOR optoelectronic integrated receiver CMOS active inductor
下载PDF
Delay and Energy Efficient Design of an On-Chip Bus with Repeaters Using a New Spatial and Temporal Encoding Technique
17
作者 张庆利 王进祥 +1 位作者 喻明艳 叶以正 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2008年第4期724-732,共9页
On-chip global buses in deep sub-micron designs consume significant amounts of energy and have large propagation delays. Thus, minimizing energy dissipation and propagation delay is an important design objective. In t... On-chip global buses in deep sub-micron designs consume significant amounts of energy and have large propagation delays. Thus, minimizing energy dissipation and propagation delay is an important design objective. In this paper, we propose a new spatial and temporal encoding approach for generic on-chip global buses with repeaters that enables higher performance while reducing peak energy and average energy. The proposed encoding approach exploits the benefits of a temporal encoding circuit and spatial bus-invert coding techniques to simultaneously eliminate opposite transitions on adjacent wires and reduce the number of self-transitions and coupling-transitions. In the design process of applying encoding techniques for reduced bus delay and energy, we present a repeater insertion design methodology to determine the repeater size and inter-repeater bus length, which minimizes the total bus energy dissipation while satisfying target delay and slew-rate constraints. This methodology is employed to obtain optimal energy versus delay trade-offs under slew-rate constraints for various encoding techniques. 展开更多
关键词 on-chip buses DELAY energy ENCODING REPEATERS
下载PDF
Full Wave Analysis of a Broad Wall Waveguide Slot Coupler
18
作者 任武 丁四如 高本庆 《Journal of Beijing Institute of Technology》 EI CAS 2002年第4期364-368,共5页
A rigorous analysis of a broad wall slot coupler composed of two crossed rectangular waveguides by using FDTD method is presented. Two types of slots, a longitudinal/transverse slot and a centered-inclined slot, are a... A rigorous analysis of a broad wall slot coupler composed of two crossed rectangular waveguides by using FDTD method is presented. Two types of slots, a longitudinal/transverse slot and a centered-inclined slot, are analyzed. Coupling slot characteristics are obtained, including scattering parameters and the resonant length for different waveguide dimensions and frequencies. The numerical results are all in good agreement with those by the method of moments. A coupler system with a short circuit port is also analyzed to help designing the slot array. 展开更多
关键词 slot coupler FDTD longitudinal/transverse slot centered-inclined slot
下载PDF
Maneuvering target tracking using threshold interacting multiple model algorithm
19
作者 徐迈 山秀明 徐保国 《Journal of Southeast University(English Edition)》 EI CAS 2005年第4期440-444,共5页
To avoid missing track caused by the target maneuvers in automatic target tracking system, a new maneuvering target tracking technique called threshold interacting multiple model (TIMM) is proposed. This algorithm i... To avoid missing track caused by the target maneuvers in automatic target tracking system, a new maneuvering target tracking technique called threshold interacting multiple model (TIMM) is proposed. This algorithm is based on the interacting multiple model (IMM) method and applies a threshold controller to improve tracking accuracy. It is also applicable to other advanced algorithms of IMM. In this research, we also compare the position and velocity root mean square (RMS) errors of TIMM and IMM algorithms with two different examples. Simulation results show that the TIMM algorithm is superior to the traditional IMM alzorithm in estimation accuracy. 展开更多
关键词 maneuvering target tracking Kalman filter interacting multiple model (IMM) threshold interacting multiple model (TIMM)
下载PDF
Waveguide Optimization for a 9.0μm GaAs-Based Quantum Cascade Laser
20
作者 李路 刘峰奇 +2 位作者 邵烨 刘俊岐 王占国 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2007年第1期31-35,共5页
Improved waveguide designs for 9.0μm GaAs-based quantum cascade laser (QCL) structures are presented. Modal losses and confinement factors are calculated for TM modes with the transfer matrix method (TMM) and eff... Improved waveguide designs for 9.0μm GaAs-based quantum cascade laser (QCL) structures are presented. Modal losses and confinement factors are calculated for TM modes with the transfer matrix method (TMM) and effective index method (EIM). The thicknesses of the cladding layer and waveguide layer, the ridge-width, and the cavity length are all taken into account. Appropriate thicknesses of epilayers are given with lower threshold gain and more economical material growth time. 展开更多
关键词 quantum cascade laser transfer matrix method effective index method
下载PDF
上一页 1 2 13 下一页 到第
使用帮助 返回顶部