|
|
|
题名
|
作者
|
年代
|
出处
|
被引量
|
| 1 | Research on crystal growth and properties of a new nonlinear optical crystal:Bismuth borate BiB_3O_6显示文摘BiB3O6 (BIBO) single crystals with sizes of 44 mm × 24 mm × 10 mm and weight of 24.7 g have been successfully grown by the top-seeded method. In this note, the preparation of seed, the growth of crystal and some problems encountered are reported. The lattice parameters of BIBO are a =7.1203(7)A, b = 4.9948(7)A, c = 6.5077(7)A, β= 105.586(8) ', V=222.93(5)A3, which were determined by BRUKER-P4 four-circle diffractometer. BIBO is biaxial crystal and the relative orientation of (X, Y, Z) with regard to (a, b, c) is: X|| b, (Y, c) =47.2°, (Z, a) = 31.6°, determined by the X-ray analysis combined with polarized microscopy. The second-harmonic-generation (SHG) conversion efficiency of the sample for 1.064 μm light is up to 67.7%. We have also obtained the third harmonic generation (THG) of 1.064 μm, namely, 1.064 μm + 0.532 μn →0.355 μm. BIBO crystal is free of moisture and hygroscopy. | TENG Bing, WANG Jiyang, WANG Zhengping, JIANG Huaidong, SONG Renbo, LIU Hong, HU Xiaobo, LIU Yaogang, WEI Jingqian & SHAO ZongshuState Key Laboratory of Crystal Materials, Shandong University, Ji’nan 250100, China | 2001 | Chinese Science Bulletin2001，46，21： | 10 |
| 2 | Spatial-temporal dynamics of desert vegetation and its responses to climatic variations over the last three decades:a case study of Hexi region in Northwest China显示文摘Analysis of spatial-temporal variations of desert vegetation under the background of climate changes can provide references for ecological restoration in arid and semi-arid areas.In this study,we used the Global Inventory Modeling and Mapping Studies(GIMMS)NDVI data from 1982 to 2006 and Moderate Resolution Imaging Spectroradiometer(MODIS)NDVI data from 2000 to 2013 to reveal the dynamics of desert vegetation in Hexi region of Northwest China over the past three decades.We also used the annual temperature and precipitation data acquired from the Chinese meteorological stations to analyze the response of desert vegetation to climatic variations.The average value of NDVImax(the maximum NDVI during the growing season)for desert vegetation in Hexi region increased at the rate of 0.65×10–3/a(P<0.05)from 1982 to 2013,and the significant increases of NDVImax mainly appeared in the typical desert vegetation areas.Vegetation was significantly improved in the lower reaches of Shule and Shiyang river basins,and the weighted mean center of desert vegetation mainly shifted toward the lower reaches of the two basins.Almost 95.32% of the total desert vegetation area showed positive correlation between NDVImax and annual precipitation,indicating that precipitation is the key factor for desert vegetation growth in the entire study area.Moreover,the areas with non-significant positive correlation between NDVImax and annual precipitation mainly located in the lower reaches of Shiyang and Shule river basins,this may be due to human activities.Only 7.64% of the desert vegetation showed significant positive correlation between NDVImax and annual precipitation in the Shule River Basin(an extremely arid area),indicating that precipitation is not the most important factor for vegetation growth in this basin,and further studies are needed to investigate the mechanism for this phenomenon. | YANG Xuemei LIU Shizeng YANG Taibao XU Xianying KANG Caizhou TANG Jinnian WEI Huaidong Mihretab G GHEBREZGABHER LI Zhiqi | 2016 | Journal of Arid Land2016，8，4： | 10 |
| 3 | Comprehensive test stand for high-intensity cyclotron development显示文摘A comprehensive test stand for high-intensity cyclotron development,a 10 MeV 430 μA cyclotron,has been successfully constructed at China Institute of Atomic Energy (CIAE) for the experimental verification of the viability of a 100 MeV high-intensity cyclotron (CYCIAE-100) being constructed at CIAE.The verification includes the overall design technology,detail design and engineering technology for the crucial parts of the machine,e.g.main magnet and beam diagnostics.It will also pave the way for future enhancement of the beam intensity.The test stand consists of a H-ion source,axial injection system,central region,main magnet and coil,RF resonator,stripping extraction,and auxiliary systems,which include the RF power amplifier,high voltage and DC power supplies,electric apparatus,beam diagnostics,control,vacuum,water cooling,pneumatic system,and safety interlock.This paper presents the work regarding the design and sub-system development of the test sand,and the results of the beam commissioning of the machine. | ZHANG TianJue LI ZhenGuo CHU ChengJie XING JianSheng GUAN FengPing ZHONG JunQing JI Bin GE Tao YIN ZhiGuo HOU ShiGang PAN GaoFeng YAO HongJuan LU YinLong WANG ZhenHui WU LongCheng LIN Jun JIA XianLu WEI SuMin WEN LiPeng WANG Feng XIA Le CAI HongRu XIE HuaiDong CHEN RongFan ZHANG Yan ZHANG SuPing LIU GengShou ZOU Jian AN ShiZhong YANG JianJun BI YuanJie YANG Fang | 2011 | Chinese Science Bulletin2011，56，3： | 3 |
| 4 | Associations of muscle mass,strength,and quality with all-cause mortality in China:a population-based cohort study显示文摘Background It remains unclear about the association of muscle mass,strength,and quality with death in the general Chinese population of diverse economical and geographical backgrounds.The present study aimed to comprehensively examine such associations across different regions in China.Methods Based on the China Kadoorie Biobank study,the present study included 23,290 participants who were aged 38 to 88 years and had no prevalent cardiovascular diseases or cancer.Muscle mass and grip strength were measured using calibrated instruments.Arm muscle quality was defined as the ratio of grip strength to arm muscle mass.Low muscle mass,grip strength,and arm muscle quality were defined as the sex-specific lowest quintiles of muscle mass index,grip strength,and arm muscle quality,respectively.Cox proportional hazards models yielded hazard ratios(HRs)and 95%confidence intervals(CIs)for risks of all-cause mortality in relation to muscle mass,strength,and quality.Results During a median follow-up of 3.98 years,739 participants died.The HR(95%CI)of all-cause mortality risk was 1.28(1.08–1.51)for low appendicular muscle mass index,1.38(1.16–1.62)for low total muscle mass index,1.68(1.41–2.00)for low grip strength,and 1.41(1.20–1.66)for low arm muscle quality in models adjusted for sociodemographic characteristics,lifestyle factors,and medical histories.Conclusion Low muscle mass,grip strength,and arm muscle quality are all associated with short-term increased risks of mortality,indicating the importance of maintaining normal muscle mass,strength,and quality for general Chinese adults. | Man Wu Yuxia Wei Jun Lv Yu Guo Pei Pei Jiachen Li Huaidong Du Ling Yang Yiping Chen Xiaohui Sun Hua Zhang Junshi Chen Zhengming Chen Canqing Yu Liming Li 无 | 2022 | Chinese Medical Journal2022，，11： | 2 |
| 5 | Hyper-spectral characteristics of rolled-leaf desert vegetation in the Hexi Corridor, China显示文摘Desert plants survive harsh environment using a variety of drought-resistant structural modifications and physio-ecological systems.Rolled-leaf plants roll up their leaves during periods of drought,making it difficult to distinguish between the external structures of various types of plants,it is therefore necessary to carry out spectral characteristics analysis for species identification of these rolled-leaf plants.Based on hyper-spectral data measured in the field,we analyzed the spectral characteristics of seven types of typical temperate zone rolled-leaf desert plants in the Hexi Corridor,China using a variety of mathematical transformation methods.The results show that:(1)during the vigorous growth period in July and August,the locations of the red valleys,green peaks,and three-edge parameters,namely,the red edge,the blue edge,and the yellow edge of well-developed rolled-leaf desert plants are essentially consistent with those of the majority of terrestrial vegetation types;(2)the absorption regions of liquid water,i.e.,1400-1500 and 1600-1700 nm,are the optimal bands for distinguishing various types of rolled-leaf desert plants;(3)in the leaf reflectance regions of 700-1250 nm,which is controlled by cellular structure,it is difficult to select the characteristic bands for differentiation rolled-leaf desert vegetation;and(4)after processing the spectral reflectance curves using a first-order differential,the envelope removal method,and the normalized differential ratio,we identify the other characteristic bands and parameters that can be used for identifying various types of temperate zone rolled-leaf desert plants,i.e.,the 510-560,650-700 and 1330-1380 nm regions,and the red edge amplitude.In general,the mathematical transformation methods in the study are effective tools to capture useful spectral information for species identification of rolled-leaf plants in the Hexi Corridor. | WEI Huaidong YANG Xuemei ZHANG Bo DING Feng ZHANG Weixing LIU Shizeng CHEN Fang | 2019 | Journal of Arid Land2019，11，3： | 1 |
您所在的机构暂未开通此部分的功能，请联系管理员