检索结果-南通市图书馆

Preparation and properties of solution-processed zinc tin oxide films from a new organic precursor

在线全文

学校读者我要写书评

暂无评论

science china Chemistry 2011年第4期54卷 651-655页

作者： ZHAO YunLong,DUAN Lian,QIAO Juan,ZHANG DeQiang,DONG GuiFang,WANG LiDuo & QIU Yong key laboratory of Organic Optoelectronics & Molecular engineering,ministry of education department of Chemistry,tsinghua university,beijing 100084,china 1. key laboratory of Organic Optoelectronics & Molecular engineering Ministry of Education department of Chemistry Tsinghua University Beijing 100084 China

Transparent,smooth and dense zinc tin oxide (ZTO) thin films have been successfully produced by using a new precursor solution,zinc acetate and tin(II) 2-ethylhexanoate mixed with 2-ethanolamine in *** ZTO films have been prepared by spin-coating,followed by thermal treatment in oxygen *** morphology,composition,crystallinity and band gap energy (Eg) of the ZTO thin films have been characterized by Atomic Force Microscopy (AFM),Atomic Emission Spectrometry (AES),X-ray Diffraction (XRD) and UV-vis *** conductivity of ZTO is about 9.8×10-9 S/cm,as estimated from the current-voltage (I-V) *** effect of the thermal treatment process on the morphology of ZTO thin films is also discussed.

关键词： zinc tin oxide (ZTO) solution-processed organic precursor thermal treatment process conductivity transparent

Zinc up-regulated the expression of the rice metallonthionein gene family and enhanced the zinc tolerance of yeast cells

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:materials International 2007年第10期17卷 1166-1171页

作者： Xu Yufeng, Zhou Gongke, Li Yiqin and Liu Jinyuan(laboratory of Molecular Biology and Protein science laboratory of the ministry of education, department of Biological sciences and Biotechnology, tsinghua university, beijing 100084, china) laboratory of Molecular Biology and Protein science laboratory of the ministry of education Department of Biological Sciences and Biotechnology Tsinghua University Beijing 100084 China

Northern blot and functional complementation assay were employed to analyze the effects of zinc on expression of ten rice metallothionein genes (OsMT-Is) in rice seedlings and the growth of yeast cells transformed with OsMT-Is. Northern blot revealed that in shoots of the rice seedlings treated with different Zn2+concentrations, expression of most members of OsMT-I family was increased, except the type 4 OsMT-Is (OsMT-I-4a, 4b and 4c). In roots, Zn2+significantly increased the transcription of OsMT-I-1b and OsMT-I-2c, but reduced the trascription of OsMT-I-1a and OsMT-I-3a. When these ten cDNAs were heterologously expressed in zinc sensitive yeast mutant, all transgenic yeasts showed increased tolerance to Zn2+, and zinc accumulation in these yeast cells also increased. These indicated that OsMT-I family members might respond to extra Zn2+, and they could enhance Zn2+ tolerance of cells by direct binding Zn2+.

关键词： rice metallothionein induced expression Zn2+ tolerance.

Microstructural Characteristics of CuCr50 Alloy by Laser Refining

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and materials 1998年第3期12卷 156-159页

作者： Baihe Miao Jianping He Donglang Shao(Material science and engineering School, university of science and Technology beijing, beijing 100083, china)(State key laboratory for advanced Metals and materials, university of science and Technology beijing, Beij Material science and engineering School University of Science and Technology Beijing Beijing 100083 China State key laboratory for advanced Metals and materials University of Science and Technology Beijing Beijing 100083 China

An investigation conceming the thecrostructural characterization of CuCr50 alloy layer by laser surface refining on the powder metallurgy substrate was carried out Significant refined procutectic chromium crystals distributed in an Cr-rich eutectic and high mutual solubility of Cu and Cr elements in the CuCr50 alloy were exam ined by Backscattered Eectron Imaging (BEI) and Energy Dispersive X-ray Spectrum (EDS) techniques. The results show that surface refining and alloying by high-power laser have a great potential to develop new and high performance alloys in the immiscible and limited solubility systems like Cu-Cr and other similar alloy systems.

关键词： laser refining Cu-Cr alloy mutual solubility microstructure

Competent predicate abstraction in model checking

在线全文

学校读者我要写书评

暂无评论

science china(Information sciences) 2011年第2期54卷 258-267页

作者： LI Li1,2,3, SONG XiaoYu4, GU Ming2,3 & LUO XiangYu2,3 1department of Computer science & Technology, tsinghua university, beijing 100084, china 2key laboratory for Information System Security, ministry of education of china, beijing 100084, china 3School of Software, tsinghua university, beijing 100084, china 4department of ECE, Portland State university, Portland, Oregon 97207, USA 1. department of Computer science & Technology Tsinghua University Beijing 100084 China2. Key Laboratory for Information System Security Ministry of Education of China Beijing 100084 China3. School of Software Tsinghua University Beijing 100084 China4. Department of ECE Portland State University Portland Oregon 97207 USA

The paper presents a new approach to computing the abstract state and a maximum weight heuristic method for finding the shortest counter-example in verification of imperative programs. The strategy is incorporated in a verification system based on the counterexample-guided abstraction refinement method. The proposed method slashes both the size of the abstract state space and the number of invokes of a decision procedure. A number of benchmarks are employed to evaluate the effectiveness of the approach.

关键词： program model checking predicate abstraction weight heuristic

Electronic structure of O-doped SiGe calculated by DFT+U method

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2016年第12期25卷 377-389页

作者：赵宗彦杨雯杨培志 Faculty of materials science and engineering Kunming University of Science and Technology Yunnan key laboratory of Micro/Nano materials & Technology School of Materials Science and EngineeringYunnan University key laboratory of advanced Technique & Preparation for Renewable Energy materials (ministry of education) Yunnan Normal University

To more in depth understand the doping effects of oxygen on SiGe alloys, both the micro-structure and properties of O-doped SiGe （including： bulk, （001） surface, and （110） surface） are calculated by DPT ＋ U method in the present work. The calculated results are as follows. （i） The （110） surface is the main exposing surface of SiGe, in which O impurity prefers to occupy the surface vacancy sites. （ii） For O interstitial doping on SiGe （110） surface, the existences of energy states caused by 0 doping in the band gap not only enhance the infrared light absorption, but also improve the behaviors of photo-generated carriers. （iii） The finding about decreased surface work function of O-doped SiGe （110） surface can confirm previous experimental observations. （iv） In all cases, O doing mainly induces the electronic structures near the band gap to vary, but is not directly involved in these variations. Therefore, these findings in the present work not only can provide further explanation and analysis for the corresponding underlying mechanism for some of the experimental findings reported in the literature, but also conduce to the development of μc-SiGe-based solar ceils in the future.

关键词： SiGe alloys 0 doping electronic structure density functional theory (DFT) calculations

Effect of annealing on the microstructures and Vickers hardness at room temperature of intermetallics in Mo-Si system

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2004年第2期23卷 176-181页

作者： YANG Haibo LI Wei SHAN Aidang WU Jiansheng key laboratory of ministry of education for High Temperature materials and Tests & department of Material science and Engieering, Shanghai Jiao Tong university, Shanghai 200030, china 上海交通大学教育部高温材料及高温测试开放实验室上海 200030

The microstructures and Vickers hardness at room temperature of arc-meltingprocessed intermetallics of Mo_5Si_3-MoSi_2 hypoeutectic alloy and hypereutectic alloy annealed at1200℃ for different time were investigated. Lamellar structure consisted of Mo_5Si_3 (D8m) phaseand MoSi_2 (C11_b) phase was observed in all the alloys. For Mo_5Si_3-MoSi_2 hypoeutectic alloy, thelamellar structure was found only after annealing and developed well with fine spacing on the orderof hundred nanometers after annealing at 1200℃ for 48 h. But when the annealing time was up to 96h, the well-developed lamellar structure was destroyed. For Mo_5Si_3-MoSi_2 hypereutectic alloy, thelamellar structure was found both before and after annealing. However the volume fraction andspacing of the lamellar structure did not change significantly before and after annealing. Theeffects of the formation, development and destruction of lamellar structure on Vickers hardness ofalloys were also investigated. When Mo_5Si_3-MoSi_2 hypoeutectic alloy annealed at 1200℃ for 48 h,the Vickers hardness was improved about 19% compared with that without annealing and formation oflamellar structure. The highest Vickers hardness of Mo5Si3-MoSi_2 hypereutectic was increasing about18% when annealing at 1200℃ for 48 h.

关键词： material experiment lamellar structure microstructure vickers hardness anneal intermetallics Mo-Si system

An exploration for the macroscopic physical meaning of entropy

在线全文

学校读者我要写书评

暂无评论

science china(Technological sciences) 2010年第7期53卷 1809-1816页

作者： WU Jing1 & GUO ZengYuan2 1 College of Energy and Power engineering, Nanjing university of Aeronautics and Astronautics, Nanjing 210016, china 2 key laboratory for Thermal science and Power engineering of ministry of education, School of Aerospace, tsinghua university, beijing 100084, china 1. College of Energy and Power engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China2. Key Laboratory for Thermal Science and Power Engineering of Ministry of Education School of Aerospace Tsinghua University Beijing 100084 China

The macroscopic physical meaning of entropy is analyzed based on the exergy (availability) of a combined system (a closed system and its environment), which is the maximum amount of useful work obtainable from the system and the environment as the system is brought into equilibrium with the environment. The process the system experiences can be divided in two sequent sub-processes, the process at constant volume, which represents the heat interaction of the system with the environment, and the adiabatic process, which represents the work interaction of the system with the environment. It is shown that the macroscopic physical meaning of entropy is a measure of the unavailable energy of a closed system for doing useful work through heat interaction. This statement is more precise than those reported in prior literature. The unavailability function of a closed system can be defined as T0S and p0V in volume constant process and adiabatic process, respectively. Their changes, that is, AiTgS) and A (p0V) represent the unusable parts of the internal energy of a closed system for doing useful work in corresponding processes. Finally, the relation between Clausius entropy and Boltzmann entropy is discussed based on the comparison of their expressions for absolute entropy.

关键词： entropy macroscopic physical meaning exergy heat interaction

Effects of chronic exposure to nonylphenol on locomotor activity and social behavior in zebrafish(Danio rerio)

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental sciences 2010年第9期22卷 1435-1440页

作者： Jigang Xia,Cuijuan Niu ,Xuejiao Pei ministry of education key laboratory of Biodiversity science and Ecological engineering,College of Life sciences,beijing Normal university,100875 beijing,china. [a] ministry of education key laboratory of Biodiversity science Ecological engineering College of Life Sciences Beijing Normal University 100875 Beijing China

Nonylphenol （NP）, a xenoestrogen ubiquitously found in aquatic ecosystems, is of high environmental concern. The present work assessed the effects of exposure to NP on locomotor activity and social behavior in male and female zebrafish （Danio rerio）, to evaluate the possible hazard of NP to fish behavior and to pursue a potential biomarker of NP contamination. Fish were randomly divided into six groups. Five groups were receiving 0.1, 1, 10, 50 and 100 μg/L nominal concentrations of NP for 60 days, respectively. A sixth control group was given the same treatment as the other five groups, but no NP. Locomotor activity, aggressive behavior, group preference and leaving shoal were examined. NP exposure showed marked influence on locomotor activity of the male zebrafish, whereas that of the female was not significantly affected by NP. Aggressive behavior and group preference were significantly affected by NP exposure in both male and female groups. Locomotor activity and aggressive behavior of the male and group preference of both male and female zebrafish were clearly inhibited at 100 μg/L NP. No significant alteration in leaving shoal was observed under NP exposure. The results suggested that changes in locomotor activity and aggressive behavior of the male and group preference of both male and female may be used as an ecologically relevant integrative biomarker of NP contamination.

关键词： chronic toxicity nonylphenol biomarker zebrafish

Effect of additive elements on exchange coupling and spin reorientation transition of nanocrystalline single-phase Nd-Fe-B alloy

在线全文

学校读者我要写书评

暂无评论

science china(Technological sciences) 2010年第9期53卷 2323-2327页

作者： BAO XiaoQian,GAO XueXu,ZHU Jie & ZHOU ShouZeng State key laboratory for advanced Metals and materials,university of science and Technology beijing,beijing 100083,china 1. State key laboratory for advanced Metals and materials University of Science and Technology Beijing Beijing 100083 China

Nd12.3Fe81.7-xZrxB6.0 (x=0,1.5) and (NdDyTb)12.3(FeZrNbCu)81.7-yCoyB6.0 (y=0,12) ribbons were prepared by melt spinning at 22 m/s and subsequent *** influences of Zr,Dy/Tb and Co substitutions on magnetic properties and spin reorientation transitions of nanophase Nd2Fe14B have been systematically *** with Zr-free sample,the remanence,intrinsic coercivity and maximum energy product for Nd12.3Fe80.2Zr1.5B6.0 ribbon increase by 10.8 %,17.8 % and 60.2 %,*** significant improvement of magnetic properties originates from the finer grains of the sample by introducing Zr,which leads to the stronger exchange coupling between neighboring *** intrinsic coercivity for (DyTb)-substituted ribbon is significantly increased although the remanence is reduced,which could be compensated by the substitution of Co for *** spin reorientation temperature Tsr of nanocrystalline Nd2Fe14B alloys was determined by measuring the ac magnetic *** was found to be lower than that of bulk *** substitutions of Zr,Dy/Tb and Co result in reduction of *** smaller the grain size,the lower the Tsr will *** of spin reorientation on magnetization characteristics of nanophase Nd2Fe14B was discussed.

关键词： nanocrystalline Nd-Fe-B magnet exchange coupling spin reorientation transition magnetic properties