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High-sensitivity photovoltage based on the interfacial photoelectric effect in the SrTiO_(3-δ)/Si heterojunction

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Science China(physics,Mechanics & Astronomy) 2010年第11期53卷 2080-2083页

作者： WEN Juan 1,GUO HaiZhong 1,XING Jie 2.Lü HuiBin 1,JIN Kui-Juan 1,HE Meng 1 & YANG GuoZhen 1 1 beijing national {2. for condensed matter physics,institute of physics,chinese academy of sciences,beijing 100190,China 2.School of Materials sciences and Technology,China University of Geosciences,beijing 100083,China beijing national {2. for condensed matter physics Institute of Physics Chinese Academy of Sciences Beijing China School of Materials sciences and Technology China University of Geosciences Beijing China

A high sensitivity photovoltaic effect has been observed in a heterojunction composed of n-type wide bandgap oxide SrTiO 3-δ and p-type Si fabricated by laser molecular beam *** responsivity of open-circuit photovoltage can reach 10 4 V/W without any amplification under zero bias for the wavelength range from visible to near infrared light in nW-μW *** attribute the high performance of the photovoltage responsivity to the interfacial photoelectric effects in the SrTiO 3-δ /Si *** the experimental results,some ideas can be generalized to improve photovoltaic efficiency and develop high sensitivity photodetectors with wide bandgap oxide materials and Si.

关键词： SrTiO 3-δ/Si heterojunction interfacial photoelectric effect photovoltage

Wet-chemical synthesis and characteristics of Au nanoshell

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Science China Chemistry 2005年第5期48卷 431-435页

作者： LIU Zhongxin1,2. SONG Hongwei1, YU Lixin1,2. YANG Linmei1,2.& PAN Guohui1,2.1. Key laboratory of Excited State physics, Changchun {2. of Optics, Fine Mechanics and physics, chinese academy of sciences, Changchun 130033, China 2. Graduate School of the chinese academy of sciences, beijing 100039, China Key laboratory of Excited State physics Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun China Graduate School of the chinese academy of sciences Beijing China

Gold nanoshells were prepared by an easy wet-chemical method, with Ag nanoparticles used as the templates. Transmission electron microscopy (TEM) indicated that the shells were sphere in shape, the size was homogenous, being about 2. nm, and no hard ag-glomerates were observed. The plasma resonance absorption of gold was tuned from visible to near-infrared (NIR) with the increased volume of HAuCl4. The temperature grads (?T) of the gold nanoshell hydrosol under the exposure of an 808-nm optical fiber laser with different power den-sities were measured. The highest ?T was 30℃ (5 W/cm2. irradiation area was 2.cm2.. This kind of gold nanoshell hydrosol is a promising material to be used in biomedicine such as photo-thermal cancer therapy, and its special photothermal convert property will photothermally trigger drug release.

关键词： wet-chemical synthesis, Au, nanoshell, NIR absorption, photothermal conversion.

Light A physics in the lepton-specific two-Higgs doublet model

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Science China(physics,Mechanics & Astronomy) 2010年第11期53卷 1981-1987页

作者： CAO JunJie 1,HENG ZhaoXia 2.3 & WAN PeiHua 1 1 College of physics & Information Engineering,Henan Normal University,Xinxiang 453007,China 2.Key laboratory of Frontiers in Theoretical physics,institute of Theoretical physics,chinese academy of sciences,beijing 100190,China 3 Kavli institute for Theoretical physics China,chinese academy of sciences,beijing 100190,China College of physics & Information Engineering Henan Normal University Xinxiang China Key laboratory of Frontiers in Theoretical physics Institute of Theoretical Physics Chinese Academy of Sciences Beijing China Kavli institute for Theoretical physics China Chinese Academy of Sciences Beijing China

We examine various direct and indirect constraints on the lepton-specific two-Higgs doublet model and discuss its phenomenology at colliders in the allowed parameter *** constraints we consider come from the precision electroweak data,the direct search for Higgs boson,the muon anomalous magnetic moment,as well as some theoretical consistency *** find that in the allowed parameter space the CP-odd Higgs boson A is rather light (m A < 30 GeV with 95% possibility),which is composed dominantly by the leptonic Higgs and decays dominantly into τ + τ;while the SM-like Higgs boson h (responsible largely for electroweak symmetry breaking) decays dominantly in the mode h → AA → 4τ with a large decay width,which will make the Higgs discovery more difficult at the ***,this scenario predicts rare Z decays Z → AAA and Z →τ + τA with their branching ratios ranging from 10-8 to 10-and 10-5 to 10-4 respectively,which may be accessible at the GigaZ option of the ILC.

关键词： Lepton-specific two-Higgs doublt model light Higgs boson A Z decays

PREPARATION OF BISPHENOL A EPOXY RESIN WATERBORNE DISPERSIONS BY THE PHASE INVERSION EMULSIFICATION TECHNIQUE

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chinese Journal of Polymer Science 2000年第1期18卷 33-38页

作者： Zhen-zhong Yang De-lu Zhao Polymer physics laboratory, {2. of Chemistry, chinese academy of sciences, beijing 1.0080, China 中科院化学所高分子物理及化学国家重点实验室北京

The phase inversion emulsification technique (PIET) is an effective physical method for preparing waterborne dispersions of polymer resins. Some results concerning the preparation of bisphenol A epoxy resin waterborne dispersions by PIET in our laboratory were summarized. Electrical properties, rheological behavior and morphological evolution during phase inversion progress were systematically characterized. The effects of the emulsifier concentration and emulsification temperature on phase inversion progress and the structural features of the waterborne particles were studied as well. The deformation and break up of water drops in a shear field were analyzed in terms of micro-theology, while the interaction and coalescence dynamics of water drops were discussed in terms of DLVO theory and Smoluchowski effective collision theory, respectively. Based on the experimental results and theoretical analysis, a physical model of phase inversion progress was suggested, by which the effects of the parameters on phase inversion progress and the structural features of the waterborne particles were interpreted and predicted.

关键词： phase inversion emulsification waterborne dispersions epoxy resin mechanism physical model

Fabrication of atomically smooth SrRuO_3 thin films by laser molecular beam epitaxy

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Science China(physics,Mechanics & Astronomy) 2008年第7期51卷 745-749页

作者： LIU GuoZhen1, HE Meng1, JIN KuiJuan1, YANG GuoZhen1, Lü HuiBin1, ZHAO Kun2. ZHENG ShiJian3 & MA XiuLiang3 1 beijing national {2. for condensed matter physics, institute of physics, chinese academy of sciences, beijing 1.0080, China 2.Department of Mathematics and physics, China University of Petroleum, beijing 102.49, China 3 Shenyang national {2. for Materials Science, institute of Metal Research, chinese academy of sciences, Shenyang 110016, China beijing national {2. for condensed matter physics Institute of Physics Chinese Academy of Sciences Beijing China Department of Mathematics and physics China University of Petroleum Beijing China Shenyang national laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang China

High-quality SrRuO3 (SRO) thin films and SrTiO3/SRO bilayer were grown epitaxially on SrTiO3 (STO)(001) substrates by laser molecular beam epitaxy. The results of in situ observation of reflection high-energy electron diffraction and ex situ X-ray diffraction θ -2. scan indicate that the SRO thin films have good crystallinity. The measurements of atomic force microscopy and scan tunneling microscopy reveal that the surface of the SRO thin film is atomically smooth. The resistivity of the SRO thin film is 300 μΩ·cm at room temperature. Furthermore, the transmission electron microscopy study shows that the interfaces of STO/SRO and SRO/STO are very clear and no interfacial reaction layer was observed. The experimental results show that the SRO thin film is an excellent electrode material for devices based on perovskite oxide materials.

关键词： SrRuO3 thin film laser molecular beam epitaxy surface morphology

Cytotoxicity of carbon nanotubes

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Science China Chemistry 2008年第11期51卷 1021-1029页

作者： ZHU Ying1,2.& LI WenXin1 1 laboratory of Nano-biology and Medicine, Shanghai institute of Applied {2., chinese academy of sciences, Shanghai 2.1800, China 2.Graduate School of chinese academy of sciences, beijing 100049, China laboratory of Nano-biology and Medicine Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai China Graduate School of chinese academy of sciences Beijing China

With large-scale production and application at large scale, carbon nanotubes (CNTs) may cause ad-verse response to the environment and human health. Thus, study on bio-effects and safety of CNTs has attracted great attention from scientists and governments worldwide. This report briefly summa-rizes the main results from the in vitro toxicity study of CNTs. The emphasis is placed on the descrip-tion of a variety of factors affecting CNTs cytotoxicity, including species of CNTs, impurities contained, lengths of CNTs, aspect ratios, chemical modification, and assaying methods of cytotoxicity. However, experimental information obtained thus far on CNTs' cytotoxicity is lacking in comparability, and some-times there is controversy about it. In order to assess more accurately the potential risks of CNTs to human health, we suggest that care should be taken for issues such as chemical modification and quantitative characterization of CNTs in cytotoxicity assessment. More importantly, studies on physical and chemical mechanisms of CNTs' cytotoxicity should be strengthened; assaying methods and evaluating criteria characterized by nanotoxicology should be gradually established.

关键词： carbon nanotubes (CNTs) cell bio-security

Role of gallium wetting layer in high-quality ZnO growth on sapphire (0001) substrates

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Science China(physics,Mechanics & Astronomy) 2004年第5期47卷 612-620页

作者： ZENG Zhaoquan1,3, WANG Yong2. DU Xiaolong1, MEI Zengxia1, KONG Xianghe3, JIA Jinfeng1, XUE Qikun1 & ZHANG Ze2. 4 1. State Key laboratory for Surface physics,{2., chinese academy of sciences, beijing 1.0080, China 2. laboratory of Electron Microscopy,{2., chinese academy of sciences, beijing 1.0080, China 3. College of physics and Engineering, Qufu Normal University, Qufu 2.3165, China 4. beijing University of Technology, beijing 10002., China State Key laboratory for Surface physics Institute of Physics Chinese Academy of Sciences Beijing China College of physics and Engineering Qufu Normal University Qufu China laboratory of Electron Microscopy Institute of Physics Chinese Academy of Sciences Beijing China beijing University of Technology Beijing China

A Ga wetting layer was used to modify the surface structure of sapphire (0001) substrate to prepare high-quality ZnO film by radio frequency plasma-assisted molecule beam epitaxy. We found that this Ga layer plays a crucial role in eliminating 30 rotation domains, controlling polarity and decreasing defect density in ZnO epilayers, as demonstrated by in situ reflection high energy electron diffraction, ex situ high resolution X-ray diffraction and high resolution cross-sectional transmission electron microscopy. Zn-polar film of ZnO was determined by convergent beam electron diffraction. A Ga bilayer model is proposed to understand the effects of the Ga wetting layer on high-quality ZnO growth.

关键词： Ga wetting layer, sapphire, polarity, defect density, zinc oxide, rf-MBE, RHEED, HRXRD, TEM, CBED.

Effects of zonal perturbations of sea surface temperature on tropical equilibrium states:A cloud-resolving modeling study

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Progress in Natural Science:Materials International 2008年第4期18卷 413-419页

作者： Xiaopeng Cui , Shouting Gao laboratory of Cloud-Precipitation physics and Severe Storms, {2. of Atmospheric physics, chinese academy of sciences, beijing 10002., China laboratory of Cloud-Precipitation physics and Severe Storms Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The effects of zonal perturbations of sea surface temperature (SST) on tropical equilibrium states are investigated based on a series of two-dimensional cloud-resolving simulations with imposed zero vertical velocity, constant zonal wind, and a zonal model domain of 768 km. Four experiments with zonal SST perturbations of wavenumbers 1 (C1), 2.(C2., 4 (C3), and 8 (C4) are compared to a control experiment with zonally uniform SST (C0). The 40-day integrations show that the temperatures reach quasi-equilibrium states with dis- tinct differences. C1 and C2.produce warmer equilibrium states whereas C3 and C4 generate colder equilibrium states than C0 does. The heat budgets in the five experiments are analyzed. Compared to C0, less IR cooling over smaller clear-sky regions in C1 and more con- densational heating in C2.are responsible for warmer equilibrium states. A reduced condensational heating leads to the cold equilibrium state in C3. The interaction between convective systems in C4 causes a decrease of condensational heating, which accounts for the cold equilibrium state.

关键词： Tropical equilibrium states Sea surface temperature Zonal perturbation Cloud-resolving modeling study

Interfacial behaviors of PMMA-PEO block copolymers at the air/water interface

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Science China Chemistry 2005年第6期48卷 567-573页

作者： CHENG Caixia1, JIAO Tifeng2. TANG Rupei1, LIU Minghua2.& XI Fu1 1. State Key laboratory of Polymer physics and Chemistry, Joint laboratory of Polymer Science and Materials, institute of Chemistry, chinese academy of sciences, beijing 1.0080, China 2. CAS Key laboratory of Colloid and Interface Science, institute of Chemistry, chinese academy of sciences, beijing 1.0080, China State Key laboratory of Polymer physics and Chemistry Joint Laboratory of Polymer Science and Materials Institute of Chemistry Chinese Academy of Sciences Beijing China CAS Key laboratory of Colloid and Interface Science Institute of Chemistry Chinese Academy of Sciences Beijing China

Diblock copolymer of PMMA2.1-b-PEO114 and triblock copolymer of PMMA12.-b- PEO2.7-b-PMMA12. were synthesized and their interfacial properties at the air-water interface were investigated, where both blocks of polyethylene oxide (PEO) and poly(methyl methacrylate) (PMMA) are surface active but the former is soluble in water while the latter is not. Both the block copolymers could form monolayers with two obvious transition regions. The first transition point is around 10 mN/m, which could be assigned to the pancake-brush change of the PEO chains. The other is around 18 mN/m, which could be ascribed to the condensed packing of PMMA. The surface morphological changes during the compression of the Langmuir monolayers are inves-tigated by using the AFM and SEM methods for the films deposited at different surface pressure or molecular areas. At a lower surface pressure, a typical morphology of PEO-con- taining lipopolymers is observed. Upon compression, sphere-dominant morphologies were observed. While the diblock copolymer is easy to folding, the triblock copolymer is in favor of formation of circular domains through vesiculation.

关键词： PMMA-PEO, block copolymers, monolayer, Langmuir-Blodgett films, AFM.