期刊文献+
共找到1,288篇文章
< 1 2 65 >
每页显示 20 50 100
Numerical and analytical investigations for the SOI LDMOS with alternated high-k dielectric and step doped silicon pillars 被引量:3
1
作者 Jia-Fei Yao Yu-Feng Guo +3 位作者 Zhen-Yu Zhang Ke-Meng Yang Mao-Lin Zhang Tian Xia 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第3期460-467,共8页
This paper presents a new silicon-on-insulator(SOI) lateral-double-diffused metal-oxide-semiconductor transistor(LDMOST) device with alternated high-k dielectric and step doped silicon pillars(HKSD device). Due to the... This paper presents a new silicon-on-insulator(SOI) lateral-double-diffused metal-oxide-semiconductor transistor(LDMOST) device with alternated high-k dielectric and step doped silicon pillars(HKSD device). Due to the modulation of step doping technology and high-k dielectric on the electric field and doped profile of each zone, the HKSD device shows a greater performance. The analytical models of the potential, electric field, optimal breakdown voltage, and optimal doped profile are derived. The analytical results and the simulated results are basically consistent, which confirms the proposed model suitable for the HKSD device. The potential and electric field modulation mechanism are investigated based on the simulation and analytical models. Furthermore, the influence of the parameters on the breakdown voltage(BV) and specific on-resistance(R_(on,sp)) are obtained. The results indicate that the HKSD device has a higher BV and lower R_(on,sp) compared to the SD device and HK device. 展开更多
关键词 high-K dielectric step doped silicon PILLAR model BREAKDOWN voltage
原文传递
High order single step time delay compensation algorithm for structural active control 被引量:4
2
作者 王焕定 耿淑伟 王伟 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2002年第4期336-342,共7页
The optimal instantaneous high order single step algorithm for active control is first discussed and then, the n+1 time step controlling force vector of the instantaneous optimal algorithm is derived from way of n tim... The optimal instantaneous high order single step algorithm for active control is first discussed and then, the n+1 time step controlling force vector of the instantaneous optimal algorithm is derived from way of n time state vector. An estimating algorithm, is developed from this to solve the problem of active control with time delay compensation. The estimating algorithm based on this high order single step β method (HSM) foundation, is proven by simulation and experiment analysis, to be a valid solution to problem of active control with time delay compensation. 展开更多
关键词 active control instantaneous optimal high order SINGLE step time DELAY COMPENSATION simulation and experiment analysis
在线阅读 下载PDF
A force control high-order single-step-β method (HSM) for substructure pseudo-dynamic testing 被引量:1
3
作者 陈再现 王焕定 +1 位作者 王凤来 周广春 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2010年第6期873-879,共7页
This paper proposes a new technique which introduces the high-order single-step-β method(HSM)into the experimental study on the substructure pseudo-dynamic testing(SPDT).The technique is based on the proposed concept... This paper proposes a new technique which introduces the high-order single-step-β method(HSM)into the experimental study on the substructure pseudo-dynamic testing(SPDT).The technique is based on the proposed concept of equivalent shear stiffness which can meet the requirement of the HSM algorithm.A study is done to theoretically validate the technique by the numerical analysis of two-storey shear building structure,in comparison of the proposed substructure pseudo-dynamic testing algorithm with the central difference method(CDM).Then,a full-scale SPDT model,the three-storey frame-supported reinforced concrete short-limb masonry shear wall structure,is designed and tested to simulate the seismic response of the corresponding six-storey structure and verify the proposed force control HSM technique.Meanwhile,the techniques of both stiffness correction and force control are suggested to control algorithmic error,control error and measurement error.The results indicate that the force control HSM can be used in the full-scale multi-degree-of-freedom(MDOF)substructure pseudo-dynamic testing before descent segment of structure restoring force properties. 展开更多
关键词 high-order single-step method(HSM) force control equivalent shear stiffness correction full-scale model
在线阅读 下载PDF
COMPACT BANDPASS FILTER WITH HIGH SELECTIVITY AND WIDE STOPBAND USING SLOTTED STEPPED-IMPEDANCE RESONATOR
4
作者 X11Jin JiYuxue MiaoChen WuWen 《Journal of Electronics(China)》 2012年第1期23-26,共4页
In this paper,a Slotted Stepped-Impedance Resonator (SSIR) is proposed.Due to the slots in the low-impedance section of the conventional SIR,the new resonator has a lower fundamental resonance f0 and can provide a pot... In this paper,a Slotted Stepped-Impedance Resonator (SSIR) is proposed.Due to the slots in the low-impedance section of the conventional SIR,the new resonator has a lower fundamental resonance f0 and can provide a potential finite transmission zero fz close to f0.Based on the proposed SSIR,a fourth-order Chebychev BandPass Filter (BPF) is designed at f0=1 GHz.The measured results show that a better than-65 dB rejection is achieved on both the lower and the upper stopband.Moreover,the new filter has a wide-30 dB rejection upper stopband from 1.13f0 to 6.52f0.The fabricated filter exhibits a size of The new filter has a planar topology and is easily integrated with modern portable communication systems. 展开更多
关键词 BandPass Filter (BPF) stepped-Impedance Resonator (SIR) high selectivity Wide stopband
在线阅读 下载PDF
Achieving the high phase purity of CH_3NH_3PbI_3 film by two-step solution processable crystal engineering
5
作者 Yan Li Bin Ding +2 位作者 Guan-Jun Yang Chang-Jiu Li Cheng-Xin Li 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2018年第8期1405-1411,共7页
To date, it is still a great challenge for highly efficient perovskite devices to realize the high quality per- ovskite films with high purity, high coverage ratio and good crystallization by two-step scalable solutio... To date, it is still a great challenge for highly efficient perovskite devices to realize the high quality per- ovskite films with high purity, high coverage ratio and good crystallization by two-step scalable solution method. In this study, a series PbI2 films with tunable micro-architecture of Pbl2 crystals are prepared via solution processable crystal engineering. The perovskite film, prepared by optimized pit spacing in gas pumped PbI2 film at 1000 Pa, shows the highest film quality, including no residual Pbl2 phase, compact morphology, and improved photoluminescence intensity. A transformation kinetics shows that the pit spacing strongly influences both the mass transfer and the sequential intercalation reaction between CH3NH31 and PbI2 crystals, which ultimately determines the full reaction state of the perovskite film. The perovskite solar cells assembled by the perovskite film show both high power-conversion efficiency and good reproducibility of photovoltaic performance due to the restrained charge recombination arising from the high quality perovskite film. 展开更多
关键词 high phase purity CHHNH3PbI3 film Two-step solution method Perovskite solar cells
原文传递
基于STEP-NC的高速加工数控编程 被引量:6
6
作者 汪俊 杜世昌 +1 位作者 孟兵 桂贵生 《机械制造与自动化》 2003年第2期64-67,共4页
高速加工技术是近年来发展起来的一种集高效、优质和低耗于一身的先进制造技术,其中高速加工数控编程是高速加工技术中极为重要和非常复杂的技术。笔者在分析了传统数控编程接口局限性的基础上 ,提出基于新型数控编程接口STEP -NC的高... 高速加工技术是近年来发展起来的一种集高效、优质和低耗于一身的先进制造技术,其中高速加工数控编程是高速加工技术中极为重要和非常复杂的技术。笔者在分析了传统数控编程接口局限性的基础上 ,提出基于新型数控编程接口STEP -NC的高速加工数控编程方法。分析和阐述了STEP NC用于高速加工数控编程的主要特点 ,并给出了具体的加工实例。 展开更多
关键词 高速加工 数控编程 step-NC 接口
在线阅读 下载PDF
基于STEPS的超高层建筑人员疏散模拟研究 被引量:3
7
作者 白磊 王刘兵 《消防科学与技术》 北大核心 2017年第6期776-779,共4页
选取某超高层写字楼,使用STEPS软件进行人员疏散模拟。按照建筑设计容量和人员密度计算各楼层的人员荷载。将楼梯、不同分布高度的电梯、避难层三种疏散设施相组合,设置5种疏散方案进行模拟研究,得出不同方案下建筑内部剩余人数随时间... 选取某超高层写字楼,使用STEPS软件进行人员疏散模拟。按照建筑设计容量和人员密度计算各楼层的人员荷载。将楼梯、不同分布高度的电梯、避难层三种疏散设施相组合,设置5种疏散方案进行模拟研究,得出不同方案下建筑内部剩余人数随时间变化的曲线以及不同方案中由电梯疏散的人数占总人数的百分比,分析各疏散方案的疏散效率。研究结果表明,"楼梯+电梯+避难层"的组合为最优疏散方案,疏散效率和安全性最高。 展开更多
关键词 超高层建筑 stepS 人员疏散 电梯疏散 避难层 疏散效率
在线阅读 下载PDF
Rhodium(Ⅲ)-catalyzed [4+2] annulation of N-arylbenzamidines with1,4,2-dioxazol-5-ones: Easy access to 4-aminoquinazolines via highly selective C-H bond activation
8
作者 Jie Ren Yanzhen Huang +2 位作者 Chao Pi Xiuling Cui Yangjie Wu 《Chinese Chemical Letters》 SCIE CAS CSCD 2021年第8期2592-2596,共5页
A novel approach for the synthesis of 4-aminoquinazolines has been developed via rhodium(Ⅲ)-catalyzed [4+2] annulation of N-arylbenzamidines with 1,4,2-dioxazol-5-ones.This reaction features excellent regioselectivit... A novel approach for the synthesis of 4-aminoquinazolines has been developed via rhodium(Ⅲ)-catalyzed [4+2] annulation of N-arylbenzamidines with 1,4,2-dioxazol-5-ones.This reaction features excellent regioselectivity,broad substrate scope and high step economy,which would provide the refe rence for the construction of the fused 4-aminoquinazolines with biologically and pharmacologically active compounds. 展开更多
关键词 [4+2]Annulation N-Arylbenzamidine 4-Aminoquinazoline Excellent regioselectivity high step economy
原文传递
基于STEPS的山区高含硫气井周边居民疏散模拟研究 被引量:1
9
作者 王丽 刘茂 孟博 《南开大学学报(自然科学版)》 CAS CSCD 北大核心 2011年第6期81-87,共7页
我国高含硫气井都位于一些远郊区或偏远山区,在生产运行中已多次因出现井喷、井口溢气等险情而疏散周边居民.以山区某高含硫气井周围1 km内的居民疏散为研究对象,针对当地山峦起伏、山路坡陡等复杂地形的特点,使用STEPS软件进行模拟.根... 我国高含硫气井都位于一些远郊区或偏远山区,在生产运行中已多次因出现井喷、井口溢气等险情而疏散周边居民.以山区某高含硫气井周围1 km内的居民疏散为研究对象,针对当地山峦起伏、山路坡陡等复杂地形的特点,使用STEPS软件进行模拟.根据NASA 2009年的全球DEM数据、航拍图和实地调研结果,提供了在软件中直接绘制山区三维地形和道路网络模型的方法.在人员属性的设置中,考虑了地形坡度对不同性别和年龄的人员移动速度的影响.最后通过STEPS模拟,研究了气井周围三条主要道路上的疏散时间、疏散效率以及不同类型人员的疏散. 展开更多
关键词 山区 高含硫气井 复杂地形 stepS 三维疏散模拟
在线阅读 下载PDF
基于STEP-NC切入方式下高速铣削刀轨研究
10
作者 王雅 章四兵 《制造技术与机床》 CSCD 北大核心 2007年第1期31-34,共4页
根据STEP-NC高速铣削的不同切入方式,通过具体铣削过程中的切入角的变化对铣刀所受载荷的影响,进行了高速铣刀的有限元分析,主要解决了型腔和外轮廓周铣刀轨进刀方式的选取,对切入角的寻优自动编程技术的发展有一定的实用性。
关键词 step—NC 高速铣削 刀具轨迹 切入角度 有限元
在线阅读 下载PDF
脉冲阶梯调制高压电源模块输入侧无电压传感器控制技术研究
11
作者 陈中 曾鹏 +1 位作者 汪方斌 缪鑫 《强激光与粒子束》 北大核心 2026年第1期115-121,共7页
脉冲阶梯调制(PSM)高压电源广泛应用于超导托卡马克装置的加热系统,采用模块化拓扑结构,通过多个直流电源模块输出叠加形成高压。每个电源模块输入过欠压保护功能,通过在输入电容两端安装电压传感器进行电压检测以实现,所需电压传感器... 脉冲阶梯调制(PSM)高压电源广泛应用于超导托卡马克装置的加热系统,采用模块化拓扑结构,通过多个直流电源模块输出叠加形成高压。每个电源模块输入过欠压保护功能,通过在输入电容两端安装电压传感器进行电压检测以实现,所需电压传感器数量庞大,增加了系统检测成本,提高了硬件检测电路的复杂性。介绍了PSM高压电源电路拓扑,详细分析了PSM高压电源的PWM模块循环控制策略,在此基础上提出了一种电源模块输入侧无电压传感器电压检测方法,在PSM高压电源输出侧采用单电压传感器检测电压信号,推导出各电源模块输入侧电压。最后,基于RT-LAB实时仿真平台搭建了仿真模型,实验结果验证了所提出SVM检测方法的有效性。 展开更多
关键词 高压电源 脉冲阶梯调制 循环控制 电压检测 无电压传感器
在线阅读 下载PDF
基于STEP-NC的闭环加工技术研究与实现 被引量:7
12
作者 郑联语 梁大伟 雷沛 《计算机集成制造系统》 EI CSCD 北大核心 2011年第11期2389-2398,共10页
在研究闭环加工系统数据流需求和STEP-NC的基础上,提出了基于STEP-NC的闭环加工系统框架以及辅助实现STEP-NC执行和CAPP/CAM系统与CNC系统双向闭环的一种高层过程控制器,并对集成工艺规划、STEP-NC程序的后置处理、测量数据反馈与关联,... 在研究闭环加工系统数据流需求和STEP-NC的基础上,提出了基于STEP-NC的闭环加工系统框架以及辅助实现STEP-NC执行和CAPP/CAM系统与CNC系统双向闭环的一种高层过程控制器,并对集成工艺规划、STEP-NC程序的后置处理、测量数据反馈与关联,以及工艺改进与优化等关键技术进行了研究与实现。开发并建立了一个闭环加工系统原型,通过STEP-NC标准测试件,验证了基于STEP-NC达到闭环加工的可行性与有效性。 展开更多
关键词 step-NC 闭环加工 集成工艺规划 高层过程控制 在机检测
在线阅读 下载PDF
基于STEP-NC切入方式下高速铣削刀轨研究
13
作者 王雅 章四兵 《电子机械工程》 2007年第1期52-55,58,共5页
根据STEP-NC高速铣削的不同切入方式,通过具体铣削过程中的切入角的变化对铣刀所受载荷的影响,进行了高速铣刀的有限元分析,主要解决了型腔和外轮廓周铣刀轨进刀方式的选取,对切入角的寻优自动编程技术的发展有一定的实用性。
关键词 step-NC 高速铣削 刀具轨迹 切入角度 有限元
在线阅读 下载PDF
基于STEP的高速CNC系统研究
14
作者 王雅 章四兵 《煤矿机电》 2008年第1期41-43,共3页
针对高速加工中数控编程瓶颈问题,遵从STEP标准、面向对象的数据模型,建立STEP-NC数据模型。并以实例进行分析,初步得出特征造型系统的模型。
关键词 高速加工 CNC系统 产品模型数据转换标准
在线阅读 下载PDF
二步法合成烧结镁铝尖晶石性能分析与工艺探讨
15
作者 范连伟 王聪 +1 位作者 齐晓凤 苏鑫 《耐火与石灰》 2026年第1期38-42,共5页
以轻烧氧化镁粉和工业氧化铝粉为原料,采用二步法合成了烧结镁铝尖晶石,将其与回转窑烧结镁铝尖晶石砂的颗粒体积密度、显微结构进行了对比分析;针对二步法超高温竖窑工艺,从产品单耗、烟气环保处理及工艺流程中的关键参数进行了分析和... 以轻烧氧化镁粉和工业氧化铝粉为原料,采用二步法合成了烧结镁铝尖晶石,将其与回转窑烧结镁铝尖晶石砂的颗粒体积密度、显微结构进行了对比分析;针对二步法超高温竖窑工艺,从产品单耗、烟气环保处理及工艺流程中的关键参数进行了分析和探讨。结果表明:1)二步法合成烧结镁铝尖晶石的颗粒体积密度、晶粒尺寸达到了回转窑合成烧结镁铝尖晶石的指标水平。2)二步法超高温竖窑合成烧结镁铝尖晶石工艺中,原料应按照富镁型尖晶石比例进行配料;活性镁铝尖晶石砂的烧制温度以1400℃为宜,合成烧结镁铝尖晶石球坯的煅烧温度宜设置在1650~1750℃之间,同时应采取提高原料纯度、设置窑前筛以及确保连续出料以维持窑内物料运动状态等预防措施,避免结砣棚料、黏窑等问题的出现。3)超高温竖窑具有产品质量高、单位产品能耗低、生产效率高、烟气治理技术成熟可靠等诸多优点,可作为二步法生产高纯烧结富镁镁铝尖晶石砂的理想煅烧设备,极具发展潜力。 展开更多
关键词 二步法 超高温竖窑 烧结镁铝尖晶石砂
在线阅读 下载PDF
Simutaneous radar imaging and velocity measuring with step frequency waveforms 被引量:4
16
作者 Yuan Haotian Wen Shuliang Cheng Zhen 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第4期741-747,共7页
The principle and method of both radar target imaging and velocity measurement simultaneously based on step frequency waveforms is presented. Velocity compensation is necessary in order to obtain the good High resolut... The principle and method of both radar target imaging and velocity measurement simultaneously based on step frequency waveforms is presented. Velocity compensation is necessary in order to obtain the good High resolution range profile since this waveform is greatly sensitive to the Doppler shift. The velocity measurement performance of the four styles is analyzed with two pulse trains consisted of positive and negative step frequency waveforms. The velocity of targets can be estimated first coarsely by using the pulse trains with positive-positive step frequency combination, and then fine by positive-negative combination. Simulation results indicate that the method can accomplish the accurate estimation of the velocity with efficient computation and good anti-noise performance and obtain the good HRRP simultaneously. 展开更多
关键词 high resolution radar step frequency waveform velocity measuring high resolution range profile.
在线阅读 下载PDF
A two-step quantum secure direct communication protocol with hyperentanglement 被引量:19
17
作者 顾斌 黄余改 +1 位作者 方夏 张成义 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第10期66-70,共5页
We propose a two-step quantum secure direct communication (QSDC) protocol with hyperentanglement in both the spatial-mode and the polarization degrees of freedom of photon pairs which can in principle be produced wi... We propose a two-step quantum secure direct communication (QSDC) protocol with hyperentanglement in both the spatial-mode and the polarization degrees of freedom of photon pairs which can in principle be produced with a beta barium borate crystal. The secret message can be encoded on the photon pairs with unitary operations in these two degrees of freedom independently. This QSDC protocol has a higher capacity than the original two-step QSDC protocol as each photon pair can carry 4 bits of information. Compared with the QSDC protocol based on hyperdense coding, this QSDC protocol has the immunity to Trojan horse attack strategies with the process for determining the number of the photons in each quantum signal as it is a one-way quantum communication protocol. 展开更多
关键词 quantum secure direct communication TWO-step hyperentanglement high capacity
原文传递
High-field-induced electron detrapping in an AlGaN/GaN high electron mobility transistor 被引量:4
18
作者 付立华 陆海 +4 位作者 陈敦军 张荣 郑有炓 魏珂 刘新宇 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第10期512-515,共4页
A step stress test is carried out to study the reliability characteristics of an AlGaN/GaN high electron mobility transistor(HEMT).An anomalous critical drain-to-gate voltage with a negative temperature coefficient ... A step stress test is carried out to study the reliability characteristics of an AlGaN/GaN high electron mobility transistor(HEMT).An anomalous critical drain-to-gate voltage with a negative temperature coefficient is observed in the stress sequence,beyond which the HEMT device starts to recover from degradation induced by early lower voltage stress.While the performance degradation featuring the drain current slump stems from electron trapping in the surface or bulk states during low-to-medium bias stress,the recovery is attributed to high field induced electron detrapping.The carrier detrapping mechanism could be helpful for lessening the trapping-related performance degradation of a GaN-based HEMT. 展开更多
关键词 AlGaN/GaN HEMT step stress test high electric field electron detrapping
原文传递
双耦合电感磁集成开关电容二次型高增益变换器 被引量:1
19
作者 李洪珠 包雨林 +2 位作者 李超 陈星星 李洪亮 《电工技术学报》 北大核心 2025年第12期3964-3976,共13页
为进一步提高非隔离DC-DC变换器的高增益性,降低开关管的电压应力,提出一种双耦合电感磁集成开关电容二次型高增益变换器,采用单个开关管降低了拓扑结构的复杂度,引入两对耦合电感可以较大程度地提升变换器的高增益性、降低开关管两端... 为进一步提高非隔离DC-DC变换器的高增益性,降低开关管的电压应力,提出一种双耦合电感磁集成开关电容二次型高增益变换器,采用单个开关管降低了拓扑结构的复杂度,引入两对耦合电感可以较大程度地提升变换器的高增益性、降低开关管两端的电压应力,使用钳位结构可以吸收漏感能量再利用,可以有效缓解电压尖峰。该变换器引入磁集成技术将两对耦合电感进行解耦集成可进一步减小变换器磁件的体积和数量。该文分析变换器的主要工作波形与原理,在此基础上推导变换器的各项参数,对解耦集成磁件进行结构与参数设计并进行仿真验证,最后通过一台输入12 V、输出185 V、额定功率200 W的实验样机,验证了理论分析的正确性。 展开更多
关键词 二次型高增益变换器 开关电容 磁集成 耦合电感
在线阅读 下载PDF
带倍压单元的有源开关电感高增益变换器及其磁集成
20
作者 李洪珠 陈星星 +2 位作者 李超 包雨林 李洪亮 《电工技术学报》 北大核心 2025年第7期2191-2202,共12页
有源开关电感结构将两条支路并联,可以降低开关管电流应力,实现高效的能量转换。然而,两个有源开关的交错导通会导致控制电路变得复杂。此外,仅采用有源开关电感结构可能无法达到足够的电压增益。为了解决这些问题,该文提出带倍压单元... 有源开关电感结构将两条支路并联,可以降低开关管电流应力,实现高效的能量转换。然而,两个有源开关的交错导通会导致控制电路变得复杂。此外,仅采用有源开关电感结构可能无法达到足够的电压增益。为了解决这些问题,该文提出带倍压单元的有源开关电感高增益变换器结构。通过引入耦合电感和开关电容单元,提高电压增益。两个开关管同时开断的设计降低了控制电路的复杂度和成本。耦合电感的设计采用EIE型磁心,通过仿真和实验验证,实现两个耦合电感的解耦集成。最后,通过搭建一台输入电压为24V、输出电压为400V、满载功率为360W的实验样机,验证了所提变换器的合理性。 展开更多
关键词 有源开关电感 耦合电感 开关电容 高增益 磁集成
在线阅读 下载PDF
上一页 1 2 65 下一页 到第
使用帮助 返回顶部