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Influence of Yb^(3+) concentration on the upconversion luminescence of oxyfluoride material doped with Er^(3+)

The 3～〔rd〕International Conference on High-Performance ceramics(CICC-3)（1）

作者： Jian-Fei Wang Yuan-Hua Lin Yu Chen Lei Jiang and Ce-Wen Nan state key laboratory of new ceramics and fine processing department of materials science and engineering tsinghua university beijing 100084 P. R. china

＜正＞ NiO-NiTiO3 composite ceramics were prepared by the conventional solid state reaction process and dielectric properties were investigated as a function of frequency and temperature. The results indicate that all samples showed high dielectric constant -103 at 0.1 kHz, but a remarkable decrease of the dielectric loss appeared when the volume fraction of NiTiO3 phase reached 42.4%. Relaxor-like peaks were observed in the temperature dependence of the dielectric constant with ceramics having low composition of NiTiO3 phase （ 21.2%）. The possible response mechanism associated with the microstructure and the associated defects of the composites was discussed.

关键词： Dielectric properties NiO Microstructure Associated defects

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science china(Physics,Mechanics & Astronomy) 2010年第2期53卷 310-314页

作者： ZHAO SuLing1,XU Zheng1,WANG LiHui2 & S. Wageh3 1 Institute of Optoelectronic Technology,key laboratory of Luminescence and Optical Information (beijing Jiaotong university),Ministry of Education,beijing 100044,china 2 department of Physics,Chinese People’s Public Security university,beijing 100038,china 3 Physics & engineering Mathematics department Faculty of Electronic engineering Menufiya university,Menouf 32952,Egypt 1. Institute of Optoelectronic Technology Key Laboratory of Luminescence and Optical Information (Beijing Jiaotong University) Ministry of Education Beijing 100044 China2. Department of Physics Chinese People’s Public Security University Beijing 100038 China3. Physics & Engineering Mathematics Department Faculty of Electronic Engineering Menufiya University Menouf 32952 Egypt

In this paper,a new upconversion luminescent material co-doped with Erbium and Ytterbium is reported. The upconversion luminescence transition routes and related properties are studied. The results show that the absorption and emission intensities under excitation of 980 nm laser increase with the increase of the Yb3+ concentration. The red emission is stronger than the green emission. The energy transfer process plays an important role in the upconversion mechanism.

关键词： upconversion luminescence Er3+ Yb3+

One-dimensional photonic bandgap structure in abalone shell

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science Bulletin 2005年第14期 123-125页

作者： LI Bo1, ZHOU Ji1 LI Longtu1, LI Qi 2, HAN Shuo3 & HAO Zhibiao3 1. department of materials science and engineering, state key Labora- tory of new ceramics and fine processing, tsinghua university, Bei- jing 100084, china 2. department of materials science and engineering, university of Illi- nois at Urbana-Champaign, Urbana, IL 61801, USA 3. department of Electronic engineering, state key laboratory of Inte- grated Optoelectronics, tsinghua university, beijing 100084, china

The Crack of Harden Cement Paste Observed with Multi-technique

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Journal of Wuhan university of Technology(materials science) 2010年第6期25卷 1057-1060页

作者：沈卫国 key laboratory for Silicate materials science and engineering of Ministry of Education Wuhan University of Techoology School of materials science and engineering Wuhan University of Technology

The shrinkage of the cement paste with low water-cement ratio at different relative humidity was observed and analyzed with ESEM and deformation map *** crack morphology was observed with different magnification with SEM and FESEM,and the formation of the crack was observed with AFM between two C-S-H nano *** observation by multi technique at multi scale indicated that the shrinkage was increase with the decrease of the humidity due to the increase of the pressure of the capillary pressure,the morphology of the crack in smaller scale was similar to that in the bigger scale,the smaller crack distributed in the latticework of the bigger ones,and the crack propagated along the gap between two nano particles of C-S-H with weaker bonding.

关键词： crack cement paste shrinkage muli technique multi-scale

Quantum chemical calculations of nitrogen cages N_(12)

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Chinese science Bulletin 1997年第6期42卷 462-465页

作者： QU Hong, LI Qianshu and ZHU HesunSchool of Chemical engineering and materials science of beijing Institute of Technology, beijing 100081, china Stale key laboratory of Theoretical and Computational Chemistry, Jilin university, Changchun 130023, china School of Chemical engineering and materials science of beijing Institute of Technology Beijing China state key laboratory of Theoretical and Computational Chemistry Jilin University Changchun China

WHILE carbon fullerenes are studied theoretically, we tend to predict if there may be some pure nitrogen molecules which possibly consist of the same geometric structures as carbon fullerenes. Experimentally Vogler et al. have obtained the intermediate absorbed at 380 nm which was assigned to N6 molecules in 1980. Some reports of ab initio calculations have appeared concerning theoretical aspects of nitrogen cage-like structures. Bliznyuk et *** the geometrical structure of N20 molecules with Ih symmetry at HF level, showing that N20 has a metastable dodecahedral geometry, with 209.34 kJ of nitrogen atoms more than that of 10N2. The N20 molecule might be a very effective high energy density

关键词： nitrogen cage ab initio calculation HEDM.

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一种低温共烧AlN陶瓷基片的排胶技术

无机材料学报 1998年第3期13卷 396-400页

作者：吴音周和平刘耀诚缪卫国清华大学材料科学与工程系新型陶瓷与精细工艺国家重点实验室北京100084

介绍一种由高热导率AlN陶瓷和金属W共烧制备低温AlN陶瓷基片的排胶技术．研究了排胶过程中残余碳对AlN陶瓷基片相组成、烧结特性和微观结构的影响．结果表明：两步排胶法可以较好地解决W氧化及AlN陶瓷颗粒表面吸附残余碳的问题．

关键词：陶瓷低温共烧排胶氮化铝陶瓷烧成

Preparation and Characterization of Ordered Macroporous ZnO Films for Photonic Application

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Preparation and Characterization of Ordered Macroporous ZnO ...

Collision dynamics of He@C_(60)+He@C_(60) at low energies

The 3～〔rd〕International Conference on High-Performance ceramics(CICC-3)（1）

作者： Ming Fu Ji Zhou Ruilong Zong Bo Li and Longtu Listate key Lab of new ceramics and fine processing department of materials science and engineering tsinghua university beijing 100084 People’s Republic of china

＜正＞ Wide band-gap semiconductor ZnO film with ordered face-centered cubic （FCC） structure air holes was prepared by electrochemical process. The porous ZnO film was prepared in zinc nitrate aqueous solution, using the indium tin oxide （ITO） substrate covered with synthetic opals as cathode by potentiostatic method. In order to improve the filling ratio of ZnO in the opal interstices, various potentials were applied to control the deposition speeds. The porous ZnO film was characterized by X-ray diffraction and Scanning Electron Microscope and a photonic band gap at about 568nm was observed by micro-region reflection spectrometer in ZnO inverse opals.

关键词： Zinc oxide Macroporous Photonic crystals

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science china(Physics,Mechanics & Astronomy) 2008年第7期51卷 765-772页

作者： ZHAO Qiang1,2, ZHANG FengShou1,2,3 & ZHOU HongYu1,2 1 key laboratory of Beam Technology and material Modification of Ministry of Education, Institute of Low Energy Nuclear Physics, beijing Normal university, beijing 100875, china 2 beijing Radiation Center, beijing 100875, china 3 Center of Theoretical Nuclear Physics, National laboratory of Heavy Ion Accelerator of Lanzhou, Lanzhou 730000, china 1. key laboratory of Beam Technology and material Modification of Ministry of Education Institute of Low Energy Nuclear Physics Beijing Normal University Beijing 100875 China 2. beijing Radiation Center Beijing 100875 China 3. Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou 730000 China

A semi-empirical molecular dynamics model is developed. The central collisions of C60+C60 and He@C60+He@C60 at different incident energies are investigated based on this model. It is found that the dimer structures have been produced at proper incident energies and these fullerene dimers could be formed by a self-assembly of C60 fullerene and He@C60. The He atom has a significant effect at higher incident energy and this embedded He atom can enhance the stability of the dimer structure.

关键词： C60 He@C60 collision molecular dynamics

MD simulation of the effect of contact area and tip radius on nanoindentation

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science china(Physics,Mechanics & Astronomy) 2004年第1期47卷 101-112页

作者： CHEN Shangda1,2 & KE Fujiu1,2 1. department of Applied Physics, beijing university of Aeronautics and Astronautics, beijing 100083, china 2. state key laboratory of Non-linear Mechanics (LNM), Institute of Mechanics, Chinese Academy of sciences, beijing 100080, china Correspondence should be addressed to Chen Shangda (email: chensd@***) Received August 27, 2003 1. department of Applied Physics Beijing University of Aeronautics and Astronautics 100083 Beijing China 2. state key laboratory of Non-linear Mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences 100080 Beijing China

Molecular dynamics simulations of nanoindentation are performed on monocrystal copper. A new contact atoms method is presented for calculating the contact area. Compared with conventional methods, this method can provide the contact area more accurately not only for sink-in but also for pile-up situation. The effect of tip radius on indentation is investigated too. The results indicate that the measured hardness of the material will become higher as the tip radius increases.

关键词： nanoindentation, molecular dynamics, contact area, zero point of penetration depth, nano- hardness.