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Search Results: 1 - 10 of 104654 matches for " 沈章军 "
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网络环境下的多馆联合作业与服务
,
图书情报工作 , 1995,
Abstract: ?以中国科学院院网(casnet)环境下的书目文献信息系统为模型,简要地讨论了网络环境下多馆联合作业与服务系统的环境需求、作业重点及其功能特色,并且介绍了中国科学院中关村地区书目文献信息系统的网络平台、计算机系统平台和数据平台。
THE PROGRESS OF INFORMATION NETWORK AND INFORMATION SERVICE IN CHINA
中国信息网络和信息服务的进展

Yan Zhangjun Shen Ying,
,

现代图书情报技术 , 1995,
Abstract: In this article,the authors make a survey of the rapid development of information networkand sociali zed information service in China.And the influence of information network on information service industry is analyzed.Finally,some suggestions for making information industry and information market prosperous in China are presented too.
THE INTERLINK AMONG LIBRARY INFORMATION SYSTEMS
图书馆信息系统间的互联

Shen Ying Yan Zhangjun,
,

现代图书情报技术 , 1994,
Abstract: The article briefly discusses the interlink among library information systems on network environment as well as its purpose.The technical requirements,main tasks and characteristics for the multi library co-operating system are also described.The impact of system interlink on the libraries of China and its related progression are explored further.
双单量子阱材料的调制光谱研究
,学础,王太宏
半导体学报 , 1993,
Abstract: 本文采用光调制光谱方法测量了GaAs/Ga_(1-x)Al_xAs双单量子阱材料的光调制反射光谱(PR),同时观察到了二个单量子阱中的带间激子跃迁,采用电场调制线形可以拟合出激子跃迁的能量,与简单的有限方势阱模型的计算结果符合。并且由调制反射光谱中的Franz-Keldysh振荡,计算得到材料表面内建电场约为29.3kV/cm。
Cd_(1-x)Mn_xTe/CdTe多量子阱的光反射研究
,单伟,姜山,学础
半导体学报 , 1994,
Abstract: 本文首次报道用光调制光谱(PR)研究了Cd1-xMnxTe/GdTe半磁半导体多量子阱的能带结构和带间跃迁,观察到多量子阱的各子能级激子跃迁11H.11L,22H,33H等,并得到轻重空穴分裂为18meV.当能带偏移Qc=0.90时,理论计算的子带跃迁能量与调制光谱结果符合很好.发现低温时第二子能级跃迁比第一子能级跃迁更强,并给出了初步解释,通过变温测量,测得各子能级的温度系数并与纯CdTe及Cd1-xMaxTe混晶体材料的温度系数作了比较.
铜尾矿自然定居白茅对体内氮磷的适时分配及叶片氮磷代谢调节酶活性动态
,孙庆业,田胜尼
植物生态学报 , 2012,
Abstract: 白茅(Imperata cylindrica)为铜尾矿废弃地的自然定居优势植物。以农田正常生长的白茅居群为对照, 通过对不同生长时期的白茅体内氮(N)、磷(P)营养浓度, 叶片硝酸还原酶和酸性磷酸酶活性变化等的研究, 探讨铜尾矿胁迫下白茅在营养利用上的生理适应特征。研究结果表明, 在不同的生长时期, 白茅各器官内N、P分配存在一定的差异。在萌芽期, 两居群白茅体内的N、P均主要集中于根状茎。在花蕾期、成熟期时, 两居群白茅体内的N、P均向成熟叶片中迁移, 叶片中N、P浓度均达到最高。但在衰败期时, 铜尾矿居群白茅体内的N主要迁移到根状茎中, P在根状茎中的浓度也达到生长期中的最高值, 而农田居群白茅成熟叶片内N、P浓度依然最高。铜尾矿白茅叶片N、P的再吸收效率分别为49.54%–65.22%和74.71%–98.71%, 而在农田系统中分别为18.18%–52.81%和71.39%–84.07%; 铜尾矿白茅衰老叶片中P达到完全再吸收的程度。铜尾矿白茅叶片硝酸还原酶活性在生长旺盛期显著高于农田居群(p < 0.05), 是白茅加强对自身氮养分代谢活动调节作用的表现; 同一生长时期白茅叶片酸性磷酸酶活性在两种生境间差异性并不明显(p > 0.05), 但随着生长期的延长, 白茅叶片酸性磷酸酶活性表现出不断升高的趋势, 这有利于生长后期衰老叶片中有机P的水解再吸收。可见, 铜尾矿中生长的白茅通过对N、P养分的适时分配, 提高营养成分的再吸收效率, 调节N、P代谢相关调节酶活性的变化方式来减轻铜尾矿生境的营养胁迫。
铜尾矿自然定居白茅对体内氮磷的适时分配及叶片氮磷代谢调节酶活性动态
, 孙庆业, 田胜尼
植物生态学报 植物生态学报 , 2012, DOI: 10.3724/SP.J.1258.2012.00159
Abstract: ?白茅(Imperatacylindrica)为铜尾矿废弃地的自然定居优势植物。以农田正常生长的白茅居群为对照,通过对不同生长时期的白茅体内氮(N)、磷(P)营养浓度,叶片硝酸还原酶和酸性磷酸酶活性变化等的研究,探讨铜尾矿胁迫下白茅在营养利用上的生理适应特征。研究结果表明,在不同的生长时期,白茅各器官内N、P分配存在一定的差异。在萌芽期,两居群白茅体内的N、P均主要集中于根状茎。在花蕾期、成熟期时,两居群白茅体内的N、P均向成熟叶片中迁移,叶片中N、P浓度均达到最高。但在衰败期时,铜尾矿居群白茅体内的N主要迁移到根状茎中,P在根状茎中的浓度也达到生长期中的最高值,而农田居群白茅成熟叶片内N、P浓度依然最高。铜尾矿白茅叶片N、P的再吸收效率分别为49.54%–65.22%和74.71%–98.71%,而在农田系统中分别为18.18%–52.81%和71.39%–84.07%;铜尾矿白茅衰老叶片中P达到完全再吸收的程度。铜尾矿白茅叶片硝酸还原酶活性在生长旺盛期显著高于农田居群(p<0.05),是白茅加强对自身氮养分代谢活动调节作用的表现;同一生长时期白茅叶片酸性磷酸酶活性在两种生境间差异性并不明显(p>0.05),但随着生长期的延长,白茅叶片酸性磷酸酶活性表现出不断升高的趋势,这有利于生长后期衰老叶片中有机P的水解再吸收。可见,铜尾矿中生长的白茅通过对N、P养分的适时分配,提高营养成分的再吸收效率,调节N、P代谢相关调节酶活性的变化方式来减轻铜尾矿生境的营养胁迫。
桃果肉颜色、果皮茸毛和花粉育性性状的分子标记
俞明亮,马瑞娟,,
园艺学报 , 2006,
Abstract: 以91-42-51×瑞光2号的杂交后代共48个单株为试材,采用集群分离分析法(bsa),对桃果实的有毛/无毛、白肉/黄肉以及无花粉/有花粉3个性状进行了分子标记研究。研究获得ssr标记udp96-018(300bp)与有毛性状连锁,遗传距离4.5cm,ssr标记udp98-407(680bp)与白肉性状连锁,遗传距离为2.2cm;根据拟南芥雄性不育序列标记设计的引物扩增出的两个片段nnj-i(600bp)和nnj-i(900bp)与桃无花粉性状之间的遗传距离为0cm。这些标记的获得为桃分子标记辅助育种提供了有效的筛选手段。
考虑拉扭耦合效应的空间主缆扭转计算方法
Torsional calculation method of spatial cable with consideration of tension-torsion coupling effect

齐东春,锐利,,陈 舟
- , 2015,
Abstract: 由于钢丝集束体组成主缆的扭转刚度是受多因素影响的变量,目前空间主缆的扭转还没有可靠的计算方法。分析了影响空间主缆扭转刚度的主要因素,建立了主缆集束体考虑拉扭耦合效应的解析计算模型,推导了拉扭耦合引起的抗扭力矩的计算公式。在此基础上,讨论了主缆半径、主缆张力及扭转角对主缆扭转刚度的影响规律。从施工控制的角度分析了扭转刚度、索夹刚臂、吊索张拉次序及索夹预偏角对主缆扭转角的影响。研究结果表明:由于拉扭耦合效应的影响,在体系转换过程中随着主缆张力和扭转角的增大主缆扭转刚度呈明显的非线性增长;在施工控制中,为减小主缆的扭转变形,可在索夹安装时设置与成桥时索夹扭转方向相同的预偏角,利用吊索力通过索夹刚臂给主缆施加反向扭矩来实现对主缆扭转的主动控制,以抵消或减小主缆的扭转变形。
Because torsional stiffness of main cable which contains a plurality of steel wire is affected by many factors, there is no reliable calculation method for spatial cable torsion at present. The chief factors influencing torsional stiffness were analysed in this paper. The analytical calculation model with consideration of tension-torsion coupling effect was established, and the formula of resistance torsion moment of main cable caused by tension torsion coupling was deduced. On this basis, the influence law of main cable radius, tension and torsion angle on torsional stiffness was discussed. The impact of torsional stiffness, cable clamp rigid arm, suspender tensioning sequence and cable clamp preformed angle on main cable torsion angle was analyzed from the perspective of construction control. The results show that the torsional stiffness of main cable presents nonlinear growth trend during the system transition with the increase of tension and torsion angel because of the influence of tension-torsion coupling effect. In the construction control, in order to reduce torsion deformation of main cable, the bias angle of cable clamps can be set towards the rotation direction of cable clamp at the stage of finished bridge at the time of assembly. 〖JP2〗The active control of the main cable torsion can be realized through a reverse torque to the main cable, that is generated by applying the hanger force to the rigid arm of cable clamp. This method can offset or reduce torsional deformation of the main cable
Heavy metals pollution of Paeonia ostii land at copper-tailings reservoir of Tongling city:A preliminary study
铜陵铜尾矿凤丹种植基地重金属污染初探

SHEN Zhangjun,WANG Youbao,WANG Guanglin,YAN Mi,LI Zheng,LIU Dengyi,

应用生态学报 , 2005,
Abstract: The study on the soil and Paeonia ostii Cu, Cd, Pb and Zn at the copper-tailings reservoir of Tongling City, Anhui Province showed that the forms and contents of test heavy metals were differed in Paeonia ostii-planted and control soils. The Cu and Cd contents in control soil were 4.36-14.43 and 3.67-3.86 times of the 2nd national standard for soil environmental quality, respectively, and the composite pollution index of the heavy metals in Paeonia ostii-planted soil was up to 5.607. The heavy metals content in Paeonia ostii leaf and root-stem was in order of Cu>Zn>Pb>Cd, and that in Paeonia ostii stem and root- peel was Zn>Cu>Pb>Cd. The comparison of the heavy metals contents in Paeonia ostii with the criterion about herbal medicine showed that the Cu content in Paeonia ostii was 1.43-2.53 times of the criterion, and the Cd content was 1.17-3.17 times of the criterion.
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