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941.
We present a new scheme for investigating the usefulness of non-maximally entangled states for multi-party quantum state shar-ing in a simple and elegant manner.In our scheme,the sender,Alice shares n various probabilistic channels composed of non-maximally entangled states with n agents in a network.Our protocol involves only Bell-basis measurements,single qubit measurements,and a two-qubit unitary transformation operated by free optional agents.Our scheme is a more convenient realiza-tion because no other multipartite joint measurements are needed.Furthermore,in our scheme various probabilistic channels lessen the requirement for quantum channels,which makes it more practical for physical implementation.  相似文献   
942.
The impact of sub-lethal concentrations(0.05,0.5,5 μmol L 1) of the heavy metals copper(Cu),chromium(Cr),zinc(Zn),cadmium(Cd) and lead(Pb) on the growth and photosynthesis of Chlorella vulgaris was studied during 96 h exposure experiments.The results showed that the effects of these five metals on the growth of Chlorella vulgaris were dependent on both concentration and exposure time.It was found that 5 μmol L 1 treatments of Cu,Cr,Zn,Cd and Pb significantly inhibited the growth of Chlorella vulgaris,and the effect became weaker with an increase in exposure duration.Different effects on chlorophyll fluorescence were found for different metals,with Cu and Cr having an inhibiting effect and Zn and Cd having a promoting effect.The effects of heavy metals upon the growth and photosynthesis of Chlorella vulgaris were independent of each other and not causally related.  相似文献   
943.
Gao  LiE  Zeng  LingSen  Xie  KeJia 《科学通报(英文版)》2012,57(6):639-650
Determination of the timing and geochemical nature of early metamorphic and anatectic events in the Himalayan orogen may provide key insights into the physical and chemical behavior of lower crustal materials during the early stage of tectonic evolution in large-scale collisional belts.The Yardoi gneiss dome is the easternmost dome of the North Himalayan Gneiss Domes(NHGD),and contains three types of amphibolites with distinct mineral assemblage,elemental and radiogenic isotope geochemistry,as well as various types of gneisses.SHRIMP zircon U/Pb analyses on the garnet amphibolite and garnet-bearing biotite granitic gneiss yield ages of nearly peak metamorphism at 45.0±1.0 Ma and 47.6±1.8 Ma,respectively,which are 2 to 4 Ma older than the age for partial melting in migmatitic garnet amphibolite(43.5±1.3 Ma).Available data have demonstrated that ultra-high pressure metamorphism in the Tethyan Himalaya occurred at ~55 Ma,and high amphibolite facies to granulite facies metamorphism at 45 to 47 Ma.In addition,partial melting at thickened crustal conditions occurred at 43.5±1.3 Ma,which led to the formation of high Sr/Y ratios two-mica granites.The high-grade metamorphic rocks in the NHGD may represent the subducted front of the Indian continental lithosphere.In large collisional belts,fertile components in crustal materials could melt and form granitic melts with relatively high Na/K and Sr/Y ratios under thickened crustal conditions,significantly different from those formed by decompressional melting during rapid exhumation.  相似文献   
944.
Periodicity of Retzius lines is a key factor in dental development. In this study, we examined the periodicity of Retzius lines in fossil Pongo from South China using polarized light microscope observation of dental ground sections. The periodicities all of the 15 teeth were 9 d. Comparisons of periodicity were made with extant primates, fossil apes and hominins. Periodicity of fossil Pongo from South China was relatively long but fell within the variation of extant Pongo, Gorilla and modern human, and longer than periodicity of Pan and other extant primates. Fossil Pongo from South China was similar to Lufengpithecus and Sivapithecus, shorter than Gigantopithecus and longer than European and African fossil apes and most early hominins in periodicity. Generally, the periodicities of Asian large-body fossil apes were longer than the periodicities of European and African large-body fossil apes in Miocene. Difference among species and trend of evolution in periodicity were analyzed and discussed. We found that periodicity might gradually increase from Proconsul in early Miocene to several fossil apes in Miocene and then Gigantopithecus in Pleistocene. In addition, this study made correlate analysis between periodicity and body mass respectively in males and females of six extant apes and five fossil apes, and found that periodicity positively correlated with body mass.  相似文献   
945.
借助1971~2010年河湟地区代表性站点西宁、同仁、贵德、民和的月平均气温、相对湿度、风速、日照4个主要气象要素的观测资料,计算并分析了反映旅游气候舒适度的温湿指数和风效指数的时空变化特征.结果表明:河湟地区旅游景点的旅游舒适期较短,其中西宁、贵德、同仁的旅游舒适期主要集中于6~8月,民和旅游舒适期较长,集中于5~9月.河湟较不舒适期多在3月~5月和9~11月,多达6个月.旅游不舒适期主要在最寒冷的12~1月,对旅游出行产生严重制约.河湟地区旅游舒适期分布特征使其盛夏季节旅游度假避暑功能凸显,对高原旅游业发展极为有利.  相似文献   
946.
采用急性毒性试验方法,研究了不同质量浓度的镉离子(Cd2+)和汞离子(Hg2+)染毒对田螺肝胰脏超氧化物歧化酶(SOD)活性的影响.结果表明:低浓度的Cd2+、Hg2+溶液对田螺肝胰脏SOD活性具有抑制—诱导—抑制作用;高浓度的Cd2+、Hg2+溶液有抑制作用,抑制作用随着时间的延长和浓度的增大而增强.可以通过检测中华圆田螺SOD活性的变化,来直接评价环境中重金属污染对生物的毒性效应.  相似文献   
947.
邵戎  吴薇  张常亮 《科技信息》2012,(33):135-136,92
LotusDomino/Notes是一种优秀的电子办公平台,具有较强的安全性和稳定性,是机关、企事业单位广泛使用的办公软件.本文从发展历史、层次结构、安全认证等方面阐述了Notes系统的特点,并结合气象系统办公特点,实现Notes系统与其他办公系统的综合运用,同时介绍了解决服务器空间不足和多用户使用的方法,供读者参考。  相似文献   
948.
In the research field of proton exchange membrane fuel cells, the design of electrocatalytic activities on Pt-oxide promoter in the anode side has attracted attention for improvement of CO tolerance of Pt in anode side and a lowering of large over-potential loss of the oxygen reduction reaction on the cathode in the fuel cells. In the Pt-oxide promoter series, Pt–CeOx/C is one of the unique systems. It is because the unique behavior of CeOx such as electrochemical redox reaction between Ce3t and Ce4t in the anodic and cathodic reactions of fuel cell is observed. The present short review gives an overview of the recent works for improvement of the CO tolerance of Pt in the Pt–CeOx/C anodes and enhancement of the oxygen reduction reaction activity on Pt in the Pt–CeOx/C cathodes for fuel cell application. To show the design paradigm for fabrication of high quality Pt–CeOx/C electrodes, the authors re-introduced parts of our research results to highlight the important role of interface structure of Pt–CeOx based on the ultimate analysis results. The usefulness of the combined approach of microanalysis and the processing route design is presented.  相似文献   
949.
首次建立了N-溴代丁二酰亚胺(NBS)-曙红Y(EY)化学发光体系用于检测盐酸二甲双胍,在本化学发光体系中NBS为氧化剂、EY为能量受体.在碱性条件下,NBS氧化盐酸二甲双胍产生稳定的化学发光,向体系中加入十六烷基三甲基溴化胺(CTMAB)后,化学发光显著增强.研究了NBS浓度、EY浓度、CTMAB浓度、NaOH浓度、阀池管长和泵速等因素对化学发光强度的影响,初步探讨了此化学发光可能的机理.结果显示:在最佳实验条件下,盐酸二甲双胍的检测线性范围为2.6×10^-8~2.0×10^-5g·mL^-1,线性回归方程为I=32.763C(×10^-7g·mL^-1)+98.16,r=0.9991,方法检出限(DL=3σn-1/S)为8.5×10^-9g·mL^-1.对盐酸二甲双胍片剂(标示量为0.25g·片^-1)中盐酸二甲双胍定量分析,结果平均为0.2480g·片^-1,相对标准偏差为0.4%,加标回收率为93.8%~102.7%,结果令人满意.  相似文献   
950.
生态河道建设是目前城市发展的重要课题之一,建设人水和谐的河道生态系统,打造水生态良好、水景观优美、水文化丰富的亲水型宜居城市已成为许多城市的发展目标。就河道生态建设的现状、必要性、原则以及几种设计方案进行了一些分析和探讨。  相似文献   
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