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粉煤灰基NaA/NaX双晶型沸石分子筛构建及其协同吸附氨氮性能 被引量:3
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作者 蔡元韬 王坤 +5 位作者 郭欣辰 卢莹怡 张慧琦 韩熠垚 谢云龙 叶向荣 《无机化学学报》 SCIE CSCD 北大核心 2024年第1期124-134,共11页
以粉煤灰为原料,采用“联合改性三步合成法”——超声辅助碱熔微波晶化法联合废旧玻璃/13X晶种/NaH_(2)PO_(4)浸渍三阶段改性合成沸石分子筛(GFS);作为对比,采用传统碱熔水热法合成沸石分子筛(FS);采用“三步合成法”——超声辅助碱熔... 以粉煤灰为原料,采用“联合改性三步合成法”——超声辅助碱熔微波晶化法联合废旧玻璃/13X晶种/NaH_(2)PO_(4)浸渍三阶段改性合成沸石分子筛(GFS);作为对比,采用传统碱熔水热法合成沸石分子筛(FS);采用“三步合成法”——超声辅助碱熔微波晶化法合成沸石分子筛(WFS)。并采用X射线衍射(XRD)、扫描电镜(SEM)、傅里叶变换红外光谱(FTIR)、能量色散光谱(EDS)、N_(2)吸附-脱附等方法对材料的组成、形貌和结构进行了表征。结果表明,WFS和GFS较FS具有更高的比表面积和发达的介孔、微孔,且沸石分子筛晶型从NaA单晶型转为NaA/NaX双晶型。氨氮吸附实验结果表明,GFS(56.01 mg·g^(-1))较WFS(49.17 mg·g^(-1))和FS(39.75 mg·g^(-1))吸附性能更优,吸附动力学和热力学数据符合二级动力学模型和Langmuir模型,氨氮吸附过程为以离子交换为主的吸附,且为自发放热过程,低温促进氨氮吸附。 展开更多
关键词 联合改性三步合成法 粉煤灰 NaA/NaX双晶型 吸附氨氮
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双晶型TiO_2薄膜的低温制备及表征 被引量:13
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作者 燕姗姗 吴连弟 +1 位作者 陈锋 张金龙 《物理化学学报》 SCIE CAS CSCD 北大核心 2007年第3期414-418,共5页
采用溶胶-凝胶法低温制备了具有锐钛矿、板钛矿双晶型的TiO2薄膜.分别利用X射线衍射(XRD)、透射电子显微镜(TEM)、UV-Vis透光率曲线和原子力显微镜(AFM)等手段对所得TiO2溶胶和薄膜进行了性能表征.采用光催化降解罗丹明B水溶液评价TiO2... 采用溶胶-凝胶法低温制备了具有锐钛矿、板钛矿双晶型的TiO2薄膜.分别利用X射线衍射(XRD)、透射电子显微镜(TEM)、UV-Vis透光率曲线和原子力显微镜(AFM)等手段对所得TiO2溶胶和薄膜进行了性能表征.采用光催化降解罗丹明B水溶液评价TiO2薄膜的光催化活性.结果发现,所得TiO2薄膜具有较高的透明度和光催化活性.同时,考察了溶胶回流温度对所制备TiO2薄膜性能的影响,发现升高溶胶回流温度可以完善薄膜的晶型,增大薄膜的粗糙度,从而提高薄膜的光催化活性.溶胶回流温度为100℃时所制备的TiO2薄膜具有最高的光催化活性. 展开更多
关键词 TIO2薄膜 低温制备 双晶型 平均粗糙度 光催化活性
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论石英双晶的复杂性 被引量:2
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作者 赵珊茸 王勤燕 +1 位作者 肖平 许娅玲 《地质科技情报》 CAS CSCD 北大核心 2012年第5期8-14,共7页
石英双晶的复杂性远远超出了人们的想象。首先介绍了石英的11种双晶律,然后介绍测试鉴定石英双晶律的各种方法及存在的局限性,综述了近年来石英双晶与温压条件关系、晶格结构匹配理论方面的研究成果,最后结合我们近期用EBSD对岩石中石... 石英双晶的复杂性远远超出了人们的想象。首先介绍了石英的11种双晶律,然后介绍测试鉴定石英双晶律的各种方法及存在的局限性,综述了近年来石英双晶与温压条件关系、晶格结构匹配理论方面的研究成果,最后结合我们近期用EBSD对岩石中石英双晶的观察、测试结果,指出存在的问题及今后的研究方向。 展开更多
关键词 石英 双晶 双晶律的鉴定方法 双晶律的标意义
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半导体RSD开关预充电路设计与研究 被引量:1
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作者 王海洋 何小平 +1 位作者 徐燕 汤俊萍 《电力电子技术》 CSCD 北大核心 2007年第2期35-37,共3页
利用快速晶闸管设计了一种可用于触发大电流半导体开关的反向导通型双晶复合晶体管(Reversely Switching Dynistor,简称RSD)电路。重点介绍了RSD预充电路参数选择和触发脉冲产生电路的设计,解决了预充电路和主回路RSD开关开通后各电气... 利用快速晶闸管设计了一种可用于触发大电流半导体开关的反向导通型双晶复合晶体管(Reversely Switching Dynistor,简称RSD)电路。重点介绍了RSD预充电路参数选择和触发脉冲产生电路的设计,解决了预充电路和主回路RSD开关开通后各电气参数的配合问题。实验结果表明,当预充电路的工作电压约为800V时,RSD开关的预充峰值电流约为600A,脉冲宽度约为2μs,流过RSD开关的脉冲峰值电流可达5.3kA,脉冲宽度约为10μs。 展开更多
关键词 半导体 开关 晶闸管 触发/反向导通双晶复合晶体管
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SiGe HBT Class AB Power Amplifier for Wireless Communications 被引量:1
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作者 贾宏勇 刘志农 +1 位作者 李高庆 钱佩信 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2002年第9期921-924,共4页
Good performance SiGe power amplifiers applicable to wireless communications are demonstrated.The output power can reach more than 30dBm in class B mode.And in class AB mode,the output power at 1dB compression point (... Good performance SiGe power amplifiers applicable to wireless communications are demonstrated.The output power can reach more than 30dBm in class B mode.And in class AB mode,the output power at 1dB compression point ( P 1dB ) is 24dBm,the output third order intercept (TOI) power is 39dBm under V cc of 4V.The highest power added efficiency (PAE) and PAE at 1dB compression point are 34% and 25%,respectively.The adjacent channel power rejection for CDMA signal is more than 42dBc,which complies with IS95 specification. 展开更多
关键词 SIGE HBT microwave power amplifier
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A monolithic InGaP/GaAs HBT power amplifier for W-CDMA applications 被引量:1
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作者 黄继伟 王志功 +2 位作者 廖英豪 陈志坚 方志坚 《Journal of Southeast University(English Edition)》 EI CAS 2011年第2期132-135,共4页
A monolithic microwave integrated circuit (MMIC) power amplifier (PA) is proposed. It adopts a new on-chip bias circuit, which not only avoids the instability of the direct current bias caused by the change in the... A monolithic microwave integrated circuit (MMIC) power amplifier (PA) is proposed. It adopts a new on-chip bias circuit, which not only avoids the instability of the direct current bias caused by the change in the power supply and temperature, but also compensates deviations caused by the increase in input power. The bias circuit is a current-mirror configuration, and the feedback circuit helps to maintain bias voltage at a constant level. The gain of the feedback circuit is improved by the addition of a non-inverting amplifier within the feedback circuit. A shunt capacitor at the base node of the active bias transistor enhances the linearity of the PA. The chip is fabricated in an InGaP/GaAs heterojunction bipolar transistor (HBT) process. Measured results exhibit a 26. 6-dBm output compression point, 33.6% power-added efficiency (PAE) and - 40.2 dBc adjacent channel power ratio (ACPR) for wide-band code division multiple access (W-CDMA) applications. 展开更多
关键词 power amplifier wide-band code division multipleaccess(W-CDMA) heterojunction bipolar transistor (HBT) bias circuit gain compression
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A 162GHz Self-Aligned InP/InGaAs Heterojunction Bipolar Transistor
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作者 于进勇 严北平 +5 位作者 苏树兵 刘训春 王润梅 徐安怀 齐 鸣 刘新宇 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2006年第10期1732-1736,共5页
An emitter self-aligned InP-based single heterojunction bipolar transistor with a cutoff frequency (fT) of 162GHz is reported. The emitter size is 0.8μm × 12μm, the maximum DC gain is 120, the offset voltage ... An emitter self-aligned InP-based single heterojunction bipolar transistor with a cutoff frequency (fT) of 162GHz is reported. The emitter size is 0.8μm × 12μm, the maximum DC gain is 120, the offset voltage is 0.10V,and the typical breakdown voltage at Ic = 0. 1μA is 3.8V. This device is suitable for high-speed low-power applications,such as OEIC receivers and analog-to-digital converters. 展开更多
关键词 INP HBT SELF-ALIGNED
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InP/InGaAs Heterojunction Bipolar Transistor with Base μ-Bridge and Emitter Air-Bridge
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作者 于进勇 刘新宇 +3 位作者 苏树兵 王润梅 徐安怀 齐鸣 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2007年第2期154-158,共5页
An InP-based single-heterojunction bipolar transistor (SHBT) with base μ-bndge and emitter air-bridge is reported. Because those bridges reduce parasitic capacitance greatly, the cutoff frequency fT of the 2μm ... An InP-based single-heterojunction bipolar transistor (SHBT) with base μ-bndge and emitter air-bridge is reported. Because those bridges reduce parasitic capacitance greatly, the cutoff frequency fT of the 2μm ×12.5μm InP SHBT without de-embedding reaches 178GHz. It is critical in high-speed low power applications,such as OEIC receivers and analog-to-digital converters. 展开更多
关键词 InP HBT μ-bridge air-bridges self-aligning
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Alloy Temperature Dependence of Offset Voltage and Ohmic Contact Resistance in Thin Base InGaP/GaAs HBTs
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作者 杨威 刘训春 +2 位作者 朱旻 王润梅 申华军 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2006年第5期765-768,共4页
The alloy temperature dependence of Voffset and Rcontact is studied, and an optimal alloy temperature range for the best trade-off between Voffset and Rcontact, is given for thin base HBTs. In addition,the reason for ... The alloy temperature dependence of Voffset and Rcontact is studied, and an optimal alloy temperature range for the best trade-off between Voffset and Rcontact, is given for thin base HBTs. In addition,the reason for the high Voffset at high alloy temperature is interpreted using Schottky clamped theory. The lower Voffset of our U-shaped emitter HBT than that of traditional strip emitter HBTs is explained. 展开更多
关键词 heterojunction bipolar transistor U-shaped emitter ALLOY offset voltage
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Super Performance InGaP/GaAs Heterojunction Bipolar Transistor with Hexagonal Emitter
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作者 刘洪刚 袁志鹏 +1 位作者 和致经 吴德馨 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2003年第11期1135-1139,共5页
Super performance InGaP/GaAs heterojunction bipolar transistors (HBTs) with hexagonal emitter are described.The fabricated HBT shows excellent DC characteristics with low V CE offset voltage (<0 15V) and ... Super performance InGaP/GaAs heterojunction bipolar transistors (HBTs) with hexagonal emitter are described.The fabricated HBT shows excellent DC characteristics with low V CE offset voltage (<0 15V) and low knee voltage (<0 5V).Over 14V of the collector base breakdown voltage BV CBO and over 9V of the collector emitter breakdown voltage BV CEO are obtained.For a self aligned InGaP/GaAs HBT with 2μm×10μm emitter area,the f T is extrapolated to 92GHz and f max is extrapolated to 105GHz.These great values are obtained due to the hexagonal emitter and laterally etched undercut (LEU) of collector,indicating the great potential of InGaP/GaAs HBTs for high speed digital circuit and microwave power applications. 展开更多
关键词 HBT INGAP/GAAS hexagonal emitter
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The Bipolar Field-Effect Transistor:Ⅰ.Electrochemical Current Theory(Two-MOS-Gates on Pure-Base)
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作者 薩支唐 揭斌斌 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2007年第11期1661-1673,共13页
This paper describes the bipolar field-effect transistor (BiFET) and its theory. Analytical solution is ob- tained from partitioning the two-dimensional transistor into two one-dimensional transistors. The analysis ... This paper describes the bipolar field-effect transistor (BiFET) and its theory. Analytical solution is ob- tained from partitioning the two-dimensional transistor into two one-dimensional transistors. The analysis employs the parametric surface-electric-potential and the electrochemical (quasi-Fermi) potential-gradient driving force to compute the current. Output and transfer D. C. current and conductance versus voltage are presented over practi- cal ranges of terminal D. C. voltages and device parameters. Electron and hole surface channel currents are pres- ent simultaneously, a new feature which could provide circuit functions in one physical transistor such as the CMOS inverter and SRAM memory. 展开更多
关键词 bipolar field-effect transistor theory MOS field-effect transistor bipolar junction transistor simul-taneous hole and electron surface channel~ volume channel surface potential
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The Bipolar Field-Effect Transistor:II.Drift-Diffusion Current Theory(Two-MOS-Gates on Pure-Base)
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作者 薩支唐 揭斌斌 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2007年第12期1849-1859,共11页
This paper describes the drift-diffusion theory of the bipolar field-effect transistor (BiFET) with two identical and connected metal-oxide-silicon-gates (MOS-gates) on a thin-pure-base. Analytical solution is obt... This paper describes the drift-diffusion theory of the bipolar field-effect transistor (BiFET) with two identical and connected metal-oxide-silicon-gates (MOS-gates) on a thin-pure-base. Analytical solution is obtained by partitioning the two-dimensional transistor into two one-dimensional problems coupled by the parametric sur- face-electric-potential. Total and component output and transfer currents and conductances versus D. C. voltages from the drift-diffusion theory, and their deviations from the electrochemical (quasi-Fermi) potential-gradient theory,are presented over practical ranges of thicknesses of the silicon base and gate oxide. A substantial contri- bution from the longitudinal gradient of the square of the transverse electric field is shown. 展开更多
关键词 bipolar field-effect transistor theory MOS field-effect transistor simultaneous electron and holesurface and volume channels surface potential~ longitudinal gradient of transverse electric field
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Numerical Simulation and Analysis of Bipolar Junction Photogate Transistor for CMOS Image Sensor
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作者 金湘亮 陈杰 仇玉林 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2003年第3期250-254,共5页
A new photodetector--bipolar junction photogate transistor is presented for CMOS image sensor and its analytical model is also established.With the technical parameter of the 0.6μm CMOS process,the bipolar junction p... A new photodetector--bipolar junction photogate transistor is presented for CMOS image sensor and its analytical model is also established.With the technical parameter of the 0.6μm CMOS process,the bipolar junction photogate transistor is analyzed and simulated.The simulated results illustrate that the bipolar junction photogate transistor has the similar characteristics of the traditional photogate transistor.The photocurrent density of the bipolar junction photogate transistor increases exponentially with the incidence light power due to introducing the injection p+n junction.Its characteristic of blue response is rather improved compared to the traditional photogate transistor that benefits to increase the color photograph made up of the red,the green,and the blue. 展开更多
关键词 bipolar junction photogate transistor PHOTODETECTOR CMOS image sensor
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Super Performance InGaP/GaAs HBT with Novel Structure 被引量:6
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作者 白大夫 刘训春 +2 位作者 王润梅 袁志鹏 孙海锋 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2004年第7期756-761,共6页
A kind of super performance InGaP/GaAs HBT with f T=108GHz and f max =140GHz is demonstrated.The excellent frequency performance results from the novel structure of the U shaped emitter,together with sel... A kind of super performance InGaP/GaAs HBT with f T=108GHz and f max =140GHz is demonstrated.The excellent frequency performance results from the novel structure of the U shaped emitter,together with self aligned emitter and LEU(lateral etched undercut) technologies.The HBT with the novel structure shows a distinguished performance with BV CEO up to 25V.And excellent performance of low V offset of 105mV and V knee of 0 50V is great favor of low power applications.The differences due to the different structure are also compared. 展开更多
关键词 heterojunction bipolar transistor U shaped emitter self aligned emitter thermal handling capacity
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ISM Band Medium Power Amplifier 被引量:1
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作者 白大夫 刘训春 +1 位作者 袁志鹏 钱永学 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2004年第6期626-632,共7页
With the large-signal model extracted from the InGaP/GaAs HBT with three fingers,a three-stage,class AB power amplifier at ISM band is designed.Through the optimization of the traditional bias network,the gain compres... With the large-signal model extracted from the InGaP/GaAs HBT with three fingers,a three-stage,class AB power amplifier at ISM band is designed.Through the optimization of the traditional bias network,the gain compression at the low input power level is eliminated successfully.At 3.5V of supply voltage of the power amplifier after optimization exhibits 30dBm of maximum linear output power,43.4% of power added efficiency 109.7mA of a quite low quiescent bias current ,29.1dB of the corresponding gain,and -100dBc of the adjacent channel power rejection (ACPR) at the output power of 30dBm. 展开更多
关键词 heterojunction bipolar transistor power amplifier bias network gain compression quiescent bias current
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Novel lateral insulated gate bipolar transistor on SOI substrate for optimizing hot-carrier degradation
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作者 黄婷婷 刘斯扬 +1 位作者 孙伟锋 张春伟 《Journal of Southeast University(English Edition)》 EI CAS 2014年第1期17-21,共5页
A novel lateral insulated gate bipolar transistor on a silicon-on-insulator substrate SOI-LIGBT with a special low-doped P-well structure is proposed.The P-well structure is added to attach the P-body under the channe... A novel lateral insulated gate bipolar transistor on a silicon-on-insulator substrate SOI-LIGBT with a special low-doped P-well structure is proposed.The P-well structure is added to attach the P-body under the channel so as to reduce the linear anode current degradation without additional process.The influence of the length and depth of the P-well on the hot-carrier HC reliability of the SOI-LIGBT is studied.With the increase in the length of the P-well the perpendicular electric field peak and the impact ionization peak diminish resulting in the reduction of the hot-carrier degradation. In addition the impact ionization will be weakened with the increase in the depth of the P-well which also makes the hot-carrier degradation decrease.Considering the effect of the low-doped P-well and the process windows the length and depth of the P-well are both chosen as 2 μm. 展开更多
关键词 lateral insulated gate bipolar transistor LIGBT SILICON-ON-INSULATOR SOI hot-carrier effect HCE optimi-zation
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Performance of a Self-Aligned InP/GaInAs SHBT with a Novel T-Shaped Emitter
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作者 苏树兵 刘训春 +4 位作者 刘新宇 于进勇 王润梅 徐安怀 齐鸣 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2006年第3期434-437,共4页
A self-aligned InP/GalnAs single heterojunction bipolar transistor(HBT) is investigated using a novel T-shaped emitter. A U-shaped emitter layout,selective wet etching,laterally etched undercut, and an air-bridge ar... A self-aligned InP/GalnAs single heterojunction bipolar transistor(HBT) is investigated using a novel T-shaped emitter. A U-shaped emitter layout,selective wet etching,laterally etched undercut, and an air-bridge are applied in this process. The device, which has a 2μm×12μm U-shaped emitter area,demonstrates a common-emitter DC current gain of 170,an offset voltage of 0.2V,a knee voltage of 0.5V, and an open-base breakdown voltage of over 2V. The HBT exhibits good microwave performance with a current gain cutoff frequency of 85GHz and a maximum oscillation frequency of 72GHz, These results indicate that these InP/InGaAs SHBTs are suitable for low-voltage,low-power,and high-frequency applications. 展开更多
关键词 self-alignment emitters InP single heterojunction bipolar transistor T-shaped emitter U-shaped emitter layout
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Analytical modelling and free vibration analysis of piezoelectric bimorphs 被引量:1
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作者 周燕国 陈云敏 丁皓江 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2005年第9期938-944,共7页
An efficient and accurate analytical model for piezoelectric bimorph based on the improved first-order shear deformation theory (FSDT) is developed in this work. The model combines the equivalent single-layer approa... An efficient and accurate analytical model for piezoelectric bimorph based on the improved first-order shear deformation theory (FSDT) is developed in this work. The model combines the equivalent single-layer approach for mechanical displacements and a layerwise-type modelling of the electric potential. Particular attention is devoted to the boundary conditions on the outside faces and to the interface continuity conditions of the bimorphs for the electromechanical variables. Shear correction factor (k) is introduced to modilfy both the shear stress and the electric displacement of each layer. And the detailed mathematical derivations are presented. Free vibration problem of simply supported piezoelectric bimorphs with series or parallel arrangement is investigated for the closed circuit condition, and the results for different length-to-thickness ratios are compared with those obtained from the exact 2D solution. Excellent agreements between the present model prediction with k=-8/9 and the exact solutions are observed for the resonant frequencies. 展开更多
关键词 Piezoelectric bimorph Analytical model Free vibration Shear correction factor First-order shear deformation theory
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HBT's High Frequency Noise Modeling and Analysis
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作者 王延锋 吴德馨 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2002年第11期1140-1145,共6页
A T equivalent high frequency heterojunction bipolar transistor (HBT) noise model is reported.This model is derived from Hawkins noise model commonly used in Si BJT.The main modifications include the influence of th... A T equivalent high frequency heterojunction bipolar transistor (HBT) noise model is reported.This model is derived from Hawkins noise model commonly used in Si BJT.The main modifications include the influence of the ideality factor,emitter resistance,intrinsic base collector capacitance,extrinsic base collector capacitance and other parasitic elements of HBT represented in equivalent circuit topology.In order to calculate accurate noise parameters from the equivalent circuit,the noise correlation matrix method is used to avoid any simplifications generated in circuit transformations and complex noise measurements.The analysis of the influence of the equivalent circuit elements on the minimum noise figure is reported,the results of analysis agree well with the physics explanations.By means of the formulae derived from device physics of HBT,the influence of device parameters on the minimum noise figure is also represented. 展开更多
关键词 heterojunction bipolar transistor noise modeling noise correlation matrix
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Macroscopic Quantum Coherence in Antiferromagnetic Molecular Magnets
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作者 HUHui LURong 《Communications in Theoretical Physics》 SCIE CAS CSCD 2001年第2期245-250,共6页
The macroscopic quantum coherence in a biaxial antiferromagnetic molecular magnet in the presence of magnetic field acting parallel to its hard anisotropy axis is studied within the two-sublattice model. On the basis ... The macroscopic quantum coherence in a biaxial antiferromagnetic molecular magnet in the presence of magnetic field acting parallel to its hard anisotropy axis is studied within the two-sublattice model. On the basis of instanton technique in the spin-coherent-state path-integral representation, both the rigorous Wentzel-Kramers-Brillouin exponent and pre-exponential factor for the ground-state tunnel splitting are obtained. We find that the quantum fluctuations around the classical paths can not only induce a new quantum phase previously reported by Chiolero and Loss (Phys. Rev. Lett. 80 (1998) 169), but also have great influence on the intensity of the ground-state tunnel splitting. Those features clearly have no analogue in the ferromagnetic molecular magnets. We suggest that they may be the universal behaviors in all antiferromagnetic molecular magnets. The analytical results are complemented by exact diagonalization calculation. 展开更多
关键词 macroscopic quantum coherence two-sublattice model antiferromagnetic molecular magnets
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