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Microstructure and Orientation Evolution of Unidirectional Solidification Pure Copper during ECAP

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稀有金属材料与工程 2011年第S3期40卷 171-175页

作者： Guo Tingbiao, Ding Yutian, Yuan Xunfeng, Hu Yong State Key Lab. of gansu Advanced Non-ferrous Metal Materials, lanzhou University of Technology, lanzhou 73.050,{3. lanzhou Univ Technol State Key Lab Gansu Adv Nonferrous Met Mat Lanzhou 730050 Peoples R China

Experiment were conducted to unidirectional solidification pure copper during ECAP by route C, the samples were investigated by XRD and EBSD. The results shown that the effect of original microstructure on the subgrains orientation decrease with the increasing of strain. At low strain, in the column grain interiors first formed a band structure that the orientation quite different with the matrix. With the strain increasing, the boundaries of the band structure expanding towards to two sides, gradually partition the original column grains into subgrains, the distribution of the subgrains possesses a directional distribution characteristics and the twins occurring in subgrains. Keep on increasing strain, the original grain boundaries began to broken, low angles grain boundaries and high angles grain boundaries both occur simultaneously shows a diffusion distribution characteristics.

关键词： equal channel angular extrusion (ECAE) electron back-scattering diffraction (EBSD) grain boundaries (GBs) texture

Improvements on radiation-hardened performance of static induction transistor

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Science china(Information Sciences) 2010年第5期53卷 1089-1096页

作者： WANG YongShun 1 , LUO XianLiang 1 , LI HaiRong 2 , WANG ZiTing 1 , WU Rong 1 , ZHANG CaiZhen 2 & LI SiYuan 2 1 School of Electronic and Information Engineering, lanzhou Jiaotong University, lanzhou 73.070, china 2 Institute of Microelectronics, School of Physical Science and Technology, lanzhou University, lanzhou 73.000, china 1. School of Electronic and Information Engineering Lanzhou Jiaotong University Lanzhou 730070 China2. Institute of Microelectronics School of Physical Science and Technology Lanzhou University Lanzhou 730000 China

The radiation-hardened performances of static induction transistor (SIT) have been studied in depth in this paper. The effects of radiation of electron beam on the I-V characteristics, carrier distribution and potential distribution in the channel of SIT have been represented. A large number of electron-hole pairs are generated in the depletion region of reversely biased gate-channel PN junction. The radiation-generated electrons drift towards the drain region at high positive potential, while generated holes flow into gate region biased to the lowest potential. With the accumulation of holes in gate region, the gate potential is boosted, resulting in a decrease in the height of potential barrier in channel, and an increase in drain current. I-V characteristics of SIT in the presence of radiation have been theoretically derived, and compared with experimental results. With the increase in thickness of epitaxial layer, the radiation-hardened capability of SIT is continuously improved until the optimum thickness of 26 μm is reached. The optimum matching relationship among geometric, material and technological parameters has been represented to acquire excellent radiation-hardened performances of SIT.

关键词： static induction transistor radiation-resistant potential barrier electron beam radiationgenerated carriers

Revision of seismic design codes corresponding to building damagesin the “5.12” Wenchuan earthquake

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earthquake Engineering and Engineering Vibration 2010年第2期9卷 147-155页

作者： Wang Yayong Institute of earthquake Engineering, china Academy of Building Research, Beijing 100013. china Institute of earthquake Engineering China Academy of Building Research Beijing 100013 China

A large number of buildings were seriously damaged or collapsed in the "5.12" Wenchuan earthquake. Based on field surveys and studies of damage to different types of buildings, seismic design codes have been updated. This paper briefly summarizes some of the major revisions that have been incorporated into the "Standard for classification of seismic protection of building constructions GB50223.2008" and "Code for Seismic Design of Buildings GB50011-2001." The definition of seismic fortification class for buildings has been revisited, and as a result, the seismic classifications for schools, hospitals and other buildings that hold large populations such as evacuation shelters and information centers have been upgraded in the GB50223.2008 Code. The main aspects of the revised GB50011-2001 code include: (a) modification of the seismic intensity specified for the provinces of Sichuan, Shanxi and gansu; (b) basic conceptual design for retaining walls and building foundations in mountainous areas; (c) regularity of building configuration; (d) integration of masonry structures and precast RC floors; (e) requirements for calculating and detailing stair shafts; and (f) limiting the use of single-bay RC frame structures. Some significant examples of damage in the epicenter areas are provided as a reference in the discussion on the consequences of collapse, the importance of duplicate structural systems, and the integration of RC and masonry structures.

关键词： Wenchuan earthquake earthquake damage to buildings revision of seismic design codes

A study on the reaction of 2'-hydroxychalcones with I_2-H_2SO_4-DMSO system

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Chinese Journal of Chemistry 1994年第1期12卷 73-78页

作者： ZHANG, Fang-Jie LI, Yu-LinState Key Laboratory of Applied Organic Chemistry and Institute of Organic Chemistry, lanzhou University , lanzhou, gansu 73.00,{3. State Key Laboratory of Applied Organic Chemistry and Institute of Organic Chemistry Lanzhou University Lanzhou Gansu 73000 China

The reaction of 2'-hydroxychalcones with I_2-H_2SO_4-DMSO system has been studied. The results obtained by us are entirely different from those reported in the literature. The mechanism of this reaction has also been ... 详细信息

关键词： Reaction 2'-hydroxychalcone I_2-H_2SO_4-DMSO system.

APPLICATION OF SURFACE-ENHANCED RAMAN SPECTORSCOPY FOR CHARACTERIZING HUMIC SUBSTANCES

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Chinese Chemical Letters 1993年第4期4卷 361-362页

作者： Tong Wen NI Analytical And Testing Centre Of gansu province,lanzhou {3.Yu Hui YANG Department Of Modern Physics,lanzhou University,lanzhou {3.

Surface-enhanced Raman Spectroscopy(SERS)has been used to characterize hurnic *** using HNO_3.-roughened silver foils as the enhancing surface,both fluorescence quenching and strong SERS signals have been observed at the same *** results obtained herein show that SERS is a particularly sensitive and highly selective technique for the characterization of humic substances in the environment. Humic substances axe receiving ever-inereasing attention because of their importance in the environment. Very recently,we have reported the first successful application of Raman spectroscopy for characterizing humic *** this present paper,the application of surface-enhanced Raman spectroscopy(SERS)for humic substances has further been *** our knowledge,no such studies have previously been *** results obtained herein dearly demonstrate that SERS has a great deal of promise as an analytical method for“In Situ”characterizing humic substances in the environment.

关键词： SERS SEI APPLICATION OF SURFACE-ENHANCED RAMAN SPECTORSCOPY FOR CHARACTERIZING HUMIC SUBSTANCES

THE　PRELIMINARY　EXPLORATION　ON　BASE　ENGINEERING　REFORMATION　OF　THE　WHEAT　STRIPE　RUST　IN　THE　SOUTH　AREA　OF　gansu　province

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Natural Disaster Reduction in china 1996年第1期 37-41页

作者： Xie Pengyun(The Agriculture Department of gansu province)

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关键词： ENGINE

Analysis of the Theoretical Foundation and Engineering Effect for Air-duct Embankment on the Qinghai-Tibet Railway

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工程科学（英文版） 2007年第2期5卷 153-160页

作者： Jiang Fuqiang~ 1, 2 (1.The Northwest Research Institute Co.Ltd of CREC, lanzhou 73.000, gansu, china 2.{3. Jiaotong Universirty, {3. 73.070, gansu, china)

Based on the corresponding theories of engineering thermodynamics and hydro-dynamics, a careful study is made of the characteristics of air flow in different duct-embedded ways. According to critical Reynolds number, the atmospheric critical velocity of the duct with different diameters, which makes laminar flow different from turbulent flow, is calculated. Given the condition in which a forced flow occurs and the wind strength is larger than the atmospheric pressure gradient along the air-duct, a rational ratio of the length to the diameter is presented. Based on the above theory and field test data on soil temperature and embankment settlement, the advantages and disadvantages are discussed in details of all duct-embedded ways that might affect the stability of embankment.

关键词： Qinghai-Tibet railway air-duct embankment application permafrost engineering

Effects of precipitation and landuse on runoff during the past 50 years in a typical watershed in the Loess Plateau, china

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International Journal of Sediment Research 2009年第3期24卷 352-364页

作者： Huaxing BI1, Bin LIU2, Jie WU3. Lei YUN3. Zhihan CHEN2 and Zhewei CUI3. Prof. in hydrology, College of soil and water conservation, Box 67, Beijing Forestry University, 3. Qinghua East Road, Haidian District, Beijing 100083. china, 2 Researcher in hydrology, Xifeng station of soil and water conservation, Xifeng, gansu province, china 3.Graduate Assis., College of soil and water conservation, Beijing Forestry University, Beijing 100083. china [a] Prof. in hydrology College of soil and water conservation Box 67 Beijing Forestry University 3. Qinghua East Road Haidian District Beijing 100083 china [b] Researcher in hydrology Xifeng station of soil and water conservation Xifeng gansu province china [c] Graduate Assis. College of soil and water conservation Beijing Forestry University Beijing 100083 china

In the past century, great progress has been made worldwide in our understanding of forest-water relationship. The successful forestation programs implemented in china-which have improved the ecological environmental conditions-have gained the attention of many researchers and highlighted the relationship between forestation and water yields. The arid and semi-arid Loess Plateau has received attention from water engineers and eco-hydrological researchers in china because of a shortage in water resources. We selected one of the oldest stations conducting soil and water conservation experiments, the Xifeng soil and water conservation station, and chose the Nanxiaohe catchment and its paired catchments (Yangjiagou catchment and Dongzhuanggou catchment) as our research areas. Trends in precipitation, air temperature, streamflow over the past 50 years, and the effect of changing land use on streamflow were analyzed. The Mann-Kendall test showed that precipitation had a negative trend (downward trend), whereas air temperature showed a positive trend (upward trend) from the past to present in the Nanxiaohe catchment. However, the trends seen in precipitation, air temperature did not contain any "jumping points." The paired catchment approach is used to detect the effects of land cover change on hydrology in the Yangjiagou and the contrast catchment, i.e., Dongzhuanggou catchment in our study. The results showed a large change in land use in the Yangjiagou catchment from 1954 to 2008. An increase in forested land (from 0% to 40.08% from 1954 to 2008) and a reduction of bare land (from 51.26% to 5.50% from 1954 to 2008) accounted for a large part of the change in land use. However, the land use changed little in the contrast catchment. The comparison of streamflow in the paired catchments showed that forestation reduced streamflow by 49.63. (or 6.5 mm) each year.

关键词： Surface water hydrology Climate variability/change Forests Land use/land cover change Loess Plateau of china

GEOLOGICAL EVENT ACROSS THE BOUNDARY OF THE LATEST PALEOCENE TO EARLIEST EOCENE IN TINGRI, SOUTHERN TIBET

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地学前缘 2000年第S1期7卷 31-32页

作者： Li Xianghui 1, Wang Chengshan 1, Hu Xiumian 1, Fan Shanfa 2,Bao Xiangnong 3.(1 Chengdu University of Technology, Chengdu 610059,china 2 Guangzhou Institute of Geochemistry, Guangzhou 510640,china 3.gansu Institute of Coal,{3.,Ch

The marine early\|middle Early Paleogene in the northern Tethys Himalayas was found in southern Tibet in mid 1980s (Hao and Wan, 1985), and the bio\|, litho\|, and chrono\| stratigraphy were patterned by then (Hao and Wan, 1985; Willems et al., 1993. 1996). It seems that there is not an abrupt boundary between the Paleocene and Eocene (P/E) because they are composed of carbonate rocks. This similarity is widespread in the world. They are well examined in many ocean DSDP and ODP logs in similar continuous sediments. But in fact, it is sure that there is a geologic event between the Paleocene and Eocene around the world. Foraminifer extinction, stable isotope record, clay mineral changes, etc. verify the geologic event existence at the latest Paleocene. Unlike the K/T boundary, there is at present little direct or indirect evidence of such catastrophes coincident with the transition (Zachos et al., 1993.. This work first shows that there could be also a geologic event across the boundary of latest Paleocene to earliest Eocene exposed on land, certainly in china *** P/E transitional sediment is exposed and remeasured at Gongzha, northwestern flank of the Zhepure Shan Syncline, west to Tingri. Here the P/E transitional stratum is approximately equivalent to the upper Member IV and the entire Member V (Willems et al., 1993. 1996). The exact boundary between the Paleocene and Eocene, i.e. between the Unit 16 and Unit 17, is determined by benthic foraminiferal zonations. The fossil zone Alveolina beginning at Unit 17 is just above the boundary that is partly different from Willems et al (1993. 1996).

关键词： geological event Paleocene Eocene Tingri Southern Tibet