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A dual-band reconfigurable direct-conversion receiver RF front-end

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Journal of Semiconductors 2009年第9期30卷 91-95页

作者：姚国钦池保勇张春王志华 Institute of Microelectronics Tsinghua University

A dual-band reconfigurable wireless receiver RF front-end is presented, which is based on the directconversion principle and consists of a low noise amplifer （LNA） and a down-converter. By utilizing a compact switchable on-chip symmetrical inductor, the RF front-end could be switched between two operation frequency bands without extra die area cost. This RF front-end has been implemented in the 180 nm CMOS process and the measured results show that the front-end could provide a gain of 25 dB and IIP3 of 6 dBm at 2.2 GHz, and a gain of 18.8 dB and IIP3 of 7.3 dBm at 4.5 GHz. The whole front-end consumes 12 mA current at 1.2 V voltage supply for the LNA and 2.1 mA current at 1.8 V for the mixer, with a die area of 1.2 × 1 mm^2.

关键词： RF CMOS reconfigurable receiver direct-conversion switchable inductor

Longitudinal Vibration Analysis of Elastically Coupled Nanorods System with General Boundary Supports

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Sound & Vibration 2019年第2期53卷 16-28页

作者： Deshui Xu Jingtao Du Yuhao Zhao College of Power and Energy Engineering Harbin Engineering UniversityHarbinChina

In this paper,an accurate series solution for the longitudinal vibration analysis of elastically coupled nanorods system is established,in which artificial springs are introduced to simulate such general coupling and boundary *** formulation is derived for the description of axial dynamics of multiple coupled nanorods based on Eringen nonlocal *** each nanorod component,its longitudinal vibration displacement function is invariantly assumed as the superposition of Fourier series and boundary smoothed supplementary polynomials,with the aim to make all the spatial differential sufficiently continuous across each *** the unknown coefficients are determined in conjunction with Rayleigh-Ritz procedure to solve a standard eigenvalue *** results are presented for the particular cases of twonanorod and three-nanorod systems to demonstrate the correctness and effectiveness of the proposed *** agreements can be repeatedly observed in comparison with those from other approaches available in *** on the model established,influence of elastic boundary and coupling conditions on the longitudinal modal characteristics of multiple nanorods system is investigated and *** work can provide an efficient energy-based modeling framework for longitudinal vibration analysis of elastically connected nanorod system with complicated boundary conditions.

关键词： Longitudinal vibration nanorods system elastic boundary and coupling energy-based method

Mesoscale Simulation for Polymer Migration in Confined Uniform Shear Flow

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Chemical Research in Chinese Universities 2010年第1期26卷 122-127页

作者： HE Yan-dong WANG Yong-lei LU Zhong-yuan LI Ze-sheng State Key Laboratory of Theretical and Computational Chemistry Institute of Theoretical Chemistry Jilin University Changehun 130021P. R. China

The structure and dynamics of confined single polymer chain in a dilute solution, either in equilibrium or at different shear rates in the uniform shear flow fields, were investigated by means of dissipative particle dynamics simulations. The no-slip boundary condition without density fluctuation near the wall was taken into account to mimic the environment of a nanochannel. The dependences of the radius of gyration, especially in three different di- rections, and the density profile of the chain mass center on the strength of the confinement and the Weissenberg number（Wn） was studied. The effect of the interaction between polymer and solvent on the density profile was also investigated in the cases of moderate and strong Wn. In the high shear flow, the polymer migrates to the center of the channel with increasing Wn. There is only one density profile peak in the channel center in the uniform shear flow, which is in agreement with the results of the experiments and theory.

关键词： Confined polymer Dissipative particle dynamics No-slip boundary condition Uniform shear flow

Necking Point in PET High-speed Fiber Spinning

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Journal of Donghua University(English Edition) 2001年第1期18卷 16-20页

作者： Wang Xiaqin(王夏琴) Tang Zhilian(唐志廉) College of Environmental Science & Engineering Dong Hua University Shanghai 200051 College of Environmental Science & Engineering Dong Hua University Shanghai 200051

Cross-over method is established to predict necking point for PET high- speed fiber spinning. Even slowly crystallizing polymers such as PET can crystallize on the spinline at sufficiently high spinning speed. The development of rtmning velocity, temperature, crystallinity and theological force is investigated for the take-up velocity over a range of 6 000 - 10 000 m/min. The position of necking point, temperature rise and abrupt increase of crystallinity move closer to the spinneret with the increase of take-up velocity,

关键词： PET high-speed spinning, Simulation, necking point.

Pilot Study on Drinking Water Advanced Treatment by GAC-MF System

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Journal of Donghua University(English Edition) 2004年第1期21卷 135-139页

作者：王欣泽薛罡王宝贞王琳 School of Environmental Science and Engineering Shanghai Jiaotong University Shanghai 200240 School of Municipal & Enviromnental Engineering Harbin Institute of Technology Harbin 150090 College of Environmental Science and Engineering Donghua University Shanghai 200051 School of Municipal & Enviromnental Engineering Harbin Institute of Technology Harbin 150090 School of Municipal & Enviromnental Engineering Harbin Institute of Technology Harbin 150090he pilot performance of the combined GAC-MF membrane process for drinking water advanced treatment was described. In the process of GAC adsorption under the conditions of 20 min HRT and 6 m/h filtration rate the removal efficiencies of UV_(254) and trichloromethane could reach 40% and 50% respectively and the UV_(254) and trichloromethane in system effluent was less than 0.015 cm~(-1) and 5μg/L respectively. In the post MF membrane process MF membrane effectively retained the particles and bacteria in raw water. The effluent turbidity was less than 0.2 NTU and no bacteria were detected at all in permeate. A computer-controlled system was employed to control this system. The membrane operating parameters of backwash interval duration and flux were studied. The backwash interval of 10-min 20-min and 60-min was researched respectively and the variation of trans-membrane pressure was also analyzed. Consequently short backwash interval was recommended under the same water consume.

The pilot performance of the combined GAC-MF membrane process for drinking water advanced treatment was described. In the process of GAC adsorption, under the conditions of 20 min HRT and 6 m/h filtration rate, the removal efficiencies of UV_(254) and trichloromethane could reach 40% and 50% respectively and the UV_(254) and trichloromethane in system effluent was less than 0.015 cm^(-1) and 5μg/L respectively. In the post MF membrane process, MF membrane effectively retained the particles and bacteria in raw water. The effluent turbidity was less than 0.2 NTU and no bacteria were detected at all in permeate. A computer-controlled system was employed to control this system. The membrane operating parameters of backwash interval, duration and flux were studied. The backwash interval of 10-min, 20-min and 60-min was researched respectively, and the variation of trans-membrane pressure was also analyzed. Consequently short backwash interval was recommended under the same water consume.

关键词： granular activated carbon adsorption MF membrane drinking water advanced treatment

Dynamic CCT Diagram of Automobile Beam Steel With High Strength Produced by FTSR Technology

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Journal of Iron and Steel Research International 2008年第2期15卷 60-64页

作者： WANG Xin KANG Yong-lin YU Hao CHEN Li-bin KONG Qing-fu Materials Science and Engineering School University of Science and Technology Beijing Beijing 100083 China Center of Technology Tangshan Iron and Steel Group Company Tangshan 063016 Hebei China

The dynamic continuous cooling transformation（CCT）diagram and phase transformation rules of 510 MPa automobile beam steel,which is produced by a continuous casting of thin slab of FTSR technology in Tangshan Iron and Steel ***.,are researched by thermal simulation *** microstructure characteristics of the beam steel under different test conditions are studied by means of optical microscope and scanning electron *** test results show that the critical temperatures of phase transformation Ar3 and Ar1 will all decrease with the increase of the cooling *** the cooling rate is lower than 20 ℃·s-1,the ferrite and pearlite phase transformations are the main parts;when the cooling rate is higher than 20 ℃·s-1,the bainite phase ***,the microstructures of 510 MPa automobile beam steel produced by FTSR technology are also studied,and the results are basically in accordance with the CCT diagram gained from the test.

关键词： continuous cooling transformation automobile beam steel continuous thin slab casting microstructure characteristics

Kinetics of Chlorine Decay in Water Distribution Systems

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Journal of Donghua University(English Edition) 2004年第1期21卷 140-145页

作者：周建华薛罡赵洪宾汪永辉郭美芳 Guangzhou Municipal Engineering Design & Research Institute Guangzhou 510060 College of Environmental Science and Engineering Donghua University Shanghai 200051 School of Municipal and Environmental Engineering Harbin Institute of Technology Harbin 150090 College of Environmental Science and Engineering Donghua University Shanghai 200051 combined first and second-order model which includes bulk decay and wall decay was developed to describe chlorine decay in water distribution systems. In the model the bulk decay has complex relationships with total organic carbon (TOC) the initial chlorine concentration and the temperature. Except for the initial stages they can be simplified into a linear increase with TOC a linear decrease with initial chlorine concentration and an exponential relationship with the temperature. The model also explains why chlorine decays rapidly in the initial stages. The parameters of model are determined by deriving the best fitness with experimental data. And the accuracy of model has been verified by using the experimental data and the monitoring data in a distribution system.

A combined first and second-order model, which includes bulk decay and wall decay, was developed to describe chlorine decay in water distribution systems. In the model the bulk decay has complex relationships with total organic carbon (TOC), the initial chlorine concentration and the temperature. Except for the initial stages they can be simplified into a linear increase with TOC, a linear decrease with initial chlorine concentration and an exponential relationship with the temperature. The model also explains why chlorine decays rapidly in the initial stages. The parameters of model are determined by deriving the best fitness with experimental data. And the accuracy of model has been verified by using the experimental data and the monitoring data in a distribution system.

关键词： water distribution systems chlorine decay bulk decay wall decay

INVESTIGATION ON FRACTURE BEHAVIOR FOR WELDED JOINT OF NEW GENERATION FINE GRAINED STEEL SS400

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Acta Metallurgica Sinica(English Letters) 2003年第1期16卷 35-40页

作者： H.Y.Jing X.G.Liu Z.Q.Zhu L.X.Huo Y.F.Zhang School of Materials Science and Engineering Tianjin University Tianjin 300072 China

The fracture behavior for welded joint of new generation fine grained steel SS400 was investigated and assessed on the basis of fitness for purpose philosophy. The actual critical defect sizes for the SS400 base metal and its weld HAZ (heat affected zone) defined by the gross yielding criterium have been determined directly by means of wide plate tests. It has been shown that although the HAZ grain growth occurs due to the welding heat, the resistance to fracture is not deteriorated. The deformation behavior of wide plate specimen was also studied by finite, element (FE) analysis. The deformation of weld HAZ is protected by the high strength weld metal, so it is easier to get the general yielding for the welded joint specimen.

关键词： fine grained steel general yielding wide plate test fracture behavior

Organic Light-Emitting Devices with a LiF Hole Blocking Layer

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Chinese Physics Letters 2007年第3期24卷 828-830页

作者：连加荣袁永波周翔 State Key Lab of Optoelectronic Materials and Technologies Guangdong Province Key Lab of Display Material and Technology Sun Yat-Sen University Guangzhou 510275

We introduce a thin LiF layer into tris-8-hydroxyquinoline aluminium （Alq3 ） based bilayer organic light-emitting devices to block hole transport. By varying the thickness and position of this LiF layer in Alq3, we obtain an electroluminescent efficiency increase by a factor of two with respect to the control devices without a LiF blocking layer. By using a 10nm dye doped Alq3 sensor layer, we prove that LiF can block holes and excitons effectively. Experimental results suggest that the thin LiF layer may be a good hole and exciton blocking layer.

关键词： ENHANCED BRIGHTNESS ELECTROLUMINESCENCE EFFICIENCY INJECTION DIODES