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CATALYTIC ACTIVITIES OF RARE-EARTH CALIXARENE COMPLEXES IN POLYMER SYNTHESES

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Chinese Journal of Polymer Science 2005年第6期23卷 593-602页

作者： zhi-quan Shen Institute of Polymer Science Zhejiang University Hangzhou 310027 China

The studies of our group on the catalytic activities of rare earth calixarene complexes in polymer syntheses are reviewed. Rare earth calixarene complexes are effect catalysts for the polymerizations of butadiene, isoprene, ethylene, styrene, propylene oxide, styrene oxide, trimethylene carbonate and 2,2-dimethyl-trimethylene carbonate.

关键词： Rare earth complex Calixarene Polymer synthesis.

Multiple phase detector of M-ary phase shift keying symbols in code division multiple access systems

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Journal of Central South University 2011年第4期18卷 1080-1086页

作者： quan zhi Federal University of Juiz de fora Electrical Engineering Juiz de fora MG Brazil Zip

A novel iterative technique, the phase descent search detection was proposed. This technique constrained the solution （PDS） algorithm, for M-ary phase shift keying （M-PSK） symbols to have a unit magnitude and it was based on coordinate descent iterations where coordinates were the unknown symbol phases. The PDS algorithm, together with a descent local search （also implemented as a version of the PDS algorithm）, was used multiple times with different initializations in a proposed multiple phase detector; the solution with the minimum cost was then chosen as the final solution. The simulation results show that for highly loaded multiuser scenarios, the proposed technique has a detection performance that is close to the single-user bound. The results also show that the multiple phase detector allows detection in highly overloaded scenarios and it exhibits near-far resistance. In particular, the detector has a performance that is significantly better, and complexity that is significantly lower, than that of the detector based on semi-definite relaxation.

关键词： coordinate descent complexity M-ary phase shift keying (M-PSK) multiuser detection quadratic optimization semi-definite relaxation

Efficient multiuser detector based on box-constrained deregularization and its FPGA design

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Journal of Systems Engineering and Electronics 2012年第2期23卷 179-187页

作者： zhi quan Jie Liu Department of Electrical Engineering Federal University of Juiz de ForaJuiz de Fora 36036900Brazil School of Information Engineering Department of Electronic Information EngineeringZhengzhou UniversityZhengzhou 450001P.R.China RF Engines Limited Newport PO305WBUK

Multiuser detection can be described as a quadratic optimization problem with binary constraint. Many techniques are available to find approximate solution to this problem. These tech- niques can be characterized in terms of complexity and detection performance. The ＂efficient frontier＂ of known techniques include the decision-feedback, branch-and-bound and probabilistic data association detectors. The presented iterative multiuser detection technique is based on joint deregularized and box-constrained so- lution to quadratic optimization with iterations similar to that used in the nonstationary Tikhonov iterated algorithm. The deregulari- zation maximizes the energy of the solution, this is opposite to the Tikhonov regularization where the energy is minimized. However, combined with box-constraints, the deregularization forces the solution to be close to the binary set. We further exploit the box- constrained dichotomous coordinate descent （DCD） algorithm and adapt it to the nonstationary iterative Tikhonov regularization to present an efficient detector. As a result, the worst-case and aver- age complexity are reduced down to K28 and K2~ floating point operation per second, respectively. The development improves the ＂efficient frontier＂ in multiuser detection, which is illustrated by simulation results. Finally, a field programmable gate array （FPGA） design of the detector is presented. The detection performance obtained from the fixed-point FPGA implementation shows a good match to the floating-point implementation.

关键词： multiuser detection dichotomous coordinate descent (DCD) box-constrained DCD deregularization Tikhonov regular- ization low complexity field-programmable gate array (FPGA).

Optical Properties of *** and Nanosaws Synthesized by Thermal Evaporation Method

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Chinese Journal of Chemical Physics 2012年第2期25卷 226-230,I0004页

作者： zhi-wei Peng Bing-suo Zou School of Physics and Electronic Engineering Guangzhou UniversityGuangzhou 510006China Key Lab for Micro-Nano Optoeletronic Devices of MOE Hunan UniversityChangsha 410082China

By a simple one-step H2-assisted thermal evaporation method, high quality CdS nanos- tructures have been successfully fabricated on Au coated Si substrates in large scale. The as-synthesized CdS nanostructures consisted of sword-like nanobelts and toothed nanosaws with a single-crystal hexagonal wurtzite structure. The deposition temperature played an important role in determining the size and morphology of the CdS nanostruetures. A combination of vapor-liquid-solid and vapor-solid growth mechanisms were proposed to interpret the formation of CdS nanostructures. Photoluminescence measurement indicated that the nanobelts and nanosaws have a prominent green emission at about 512 nm, which is the band-to-band emission of CdS. The waveguide characteristics of both types of CdS nanos-truetures were observed and discussed.

关键词： CdS nanostructures Thermal evaporation Photoluminescence Optical waveguide

ANALYTICAL SOLUTION OF GROUNDWATER FLUCTUATIONS IN ESTUARINE AQUIFER

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Journal of Hydrodynamics 2005年第5期17卷 641-646页

作者： CHEN Jing ZHOU zhi-fang JIA suo-bao College of Civil Engineering Hohai University Nanjing 210098 China Hydrology and Water Resources Investigation Bureau of Jiangsu Province Nanjing 210029 China

As a basic factor in the environment of estuary, tidal effects in the coastal aquifer have recently attracted much attention because tidal dynamic also greatly influences the solute transport in the coastal aquifer. Previous studies on tidal dynamic of coastal aquifers have focused on the inland propagation of oceanic tides in the cross-shore direction, a configuration that is essentially one-dimensional. Two-dimensional analytical solutions for groundwater level fluctuation in recent papers are localized in presenting the effect of both oceanic tides and estuarine tides in quadrantal aquifer. A two-dimensional model of groundwater fluctuations in estuarine zone in proposed in this paper. Using complex transform, the two-dimensional flow equation subject to periodic boundary condition is changed into time-independent elliptic problem. Based on Green function method, an analytical solution for groundwater fluctuations in fan-shaped aquifer is derived. The response to of groundwater tidal loading in an estuary and ocean is discussed. The result show that its more extensive application than recent studies.

关键词： coastal aquifer analytical solution fanshaped area groundwater fluctuations Green function method estuary environment

Large conversion of energy in dielectric elastomers by electromechanical phase transition

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Acta Mechanica Sinica 2012年第4期28卷 1106-1114页

作者： Tong-Qing Lu zhi-Gang suo State Key Lab for Strength and Vibration of Mechanical Structures International Center of Applied MechanicsSchool of Aerospace EngineeringXi'an Jiaotong University 710049 Xi' an China School of Engineering and Applied Sciences Harvard University CambridgeMA 02138 USA

When air is pumped in, a tubular balloon initially inflates slightly and homogeneously. A short section of the balloon then forms a bulge, which coexists with the unbulged section of the balloon. As more air is pumped in, the bulged section elongates at the expense of the unbulged section, until the entire balloon is bulged. The phenomenon is analogous to the liquid-to-vapor phase transition. Here we study the bulging transition in a dielectric elastomer tube as air is pumped into the balloon and a voltage is applied through the thickness of the membrane. We formulate the condition for coexistent budged and unbulged sections, and identify allowable states set by electrical breakdown and mechanical rupture. We find that the bulging transition dramatically amplifies electromechanical energy conversion. Energy converted in an electromechanical cycle consisting of unbulged and bulged states is thousands of times that in an electromechanical cycle consisting of only unbulged states.

关键词： Dielectric elastomer Bulge Electromechanical energy conversion. Tubular balloon Electromechanical transition

Temperature Gradient Induced Orientation Change of Bi Grains in Sn–Bi57–Ag0.7 Solder Joint

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Acta Metallurgica Sinica(English Letters) 2022年第7期35卷 1184-1194页

作者： Yinbo Chen Zhaoqing Gao zhi-quan Liu Institute of Metal Research Chinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China School of Materials Science and Engineering Dalian University of TechnologyDalian 116024China Shenzhen Institute of Advanced Electronic Materials Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China

Sn-Bi-X solders are widely used in electronic packaging ***,thermomigration(TM)behaviors of Sn-BiX solder joints and the orientations change of Bi grains under the temperature gradient are rarely *** this study,Sn-Bi57-Ag0.7/Cu solder joints were used to conduct a TM test under a temperature gradient of 625℃/cm for 400 h,and an isothermal aging test at 85℃was also conducted for *** microstructural evolution of Sn-Bi-X solder joints after reflow,TM and isothermal aging were analyzed by scanning electron microscopy(SEM),transmission electron microscopy(TEM)and electron probe microanalysis(EPMA).The results indicated that the Sn/Bi areal ratio after TM did not change significantly whether at the hot end(from 46.78%/52.12%to 50.90%/48.78%)or at the cold end(from 50.25%/49.64%to 48.71%/51.16%)compared with that of as-reflowed samples due to the insufficient thermal *** thickness of intermetallic compound(IMC)after TM at hot end(2.49μm)was very close to that of the IMC at cold end(2.52μm),which was also close to that of the aged *** addition,the preferred orientations of Sn and Bi grains in different Sn–Bi–Ag solder joints resulting from different conditions(reflow,TM and isothermal aging)were characterized by electron backscatter diffraction(EBSD).The obtained results demonstrated that both Sn and Bi grains had no preferred orientation whether after reflowor isothermal aging,while the orientation of Bi grains of the sample after TM changed from random direction to c-axis([0001]direction)parallel to the heat *** 3 Sn could hinder the change of orientation of Bi grains under the temperature gradient,and the corresponding mechanism was also systematically *** study firstly revealed the orientation change of Bi grains under the temperature gradient,which would have a profound guiding significance for enhancing the reliabilities of Sn–Bi–Ag solder joints.

关键词： Sn–Bi–Ag solder Grain orientation Temperature gradient Aging Ag3Sn

Influence of External Interface Normal Stress on the Growth of Cu-Sn IMC During Aging

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Acta Metallurgica Sinica(English Letters) 2020年第10期33卷 1388-1396页

作者： Changchang Wang Yinbo Chen zhi-quan Liu Institute of Metal Research Chinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Shenzhen Institute of Advanced Electronic Materials Shenzhen Institutes of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China

A U-shape clamp was designed to apply stress perpendicular to the interface of Cu/Sn/Cu solder joints,and its influence on the growth behavior of Cu-Sn intermetallic compound(IMC)during thermal aging at 150℃ was *** results show that compared with the sample at general stress-free state,the growth rate of IMC under compression is faster,while that under tension is ***,the interface between IMC and Sn is smoother under compressive stress,and the corresponding IMC grains are smaller and more uniform than that under tensile *** to the growth kinetic analysis,the growth of IMC under general,compressive and tensile states is all controlled by the combination of grain boundary diffusion and volume diffusion with a similar growth exponent(n≈0.4).However,external stress can affect the Ostwald ripening process of grain growth,causing a change of grain size and grain boundary density in the IMC *** a result,the IMC growth behavior at the interface of the solder joint will be affected by the applied external normal stress.

关键词： Cu-Sn IMC Growth behavior External stress effect Isothermal aging

A spectral study of the interaction between chelerythrine chloride and cytidine

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Chinese Chemical Letters 2007年第6期18卷 722-725页

作者： Xiao Yan Zhang quan Ling suo Xiong Hui Wei Department of Applied Chemistry College of Chemistry & Molecular Engineering Peking University Beijing 100871 China Department of Chemical Engineering Inner Mongolia University of Technology Huhhot 010042 China

To study the possible anticancer mechanisms of chelerythrine (CHE), and its interactions with cytidine were investigated by UV–vis spectrophotometric and spectrofluorimetric measurements and by thermodynamic calculations. The binding of CHE to cytidine could be characterized by the hypochromic and bathochromic effects in the absorption bands, and the quenching of fluorescence intensity. The spectral data were fit by linear analysis, yielding a binding constant of 2.49 × 10(4) L mol(?1)at 25 °C of CHE and cytidine, and a van’t Hoff enthalpy of ?20.02 kJ/mol for the exothermic interaction in the standard state. In addition, with and , the interactions should be entropy-driven.

关键词： Chelerythrine Cytidine Fluorescence quenching UV Thermodynamic