29 resultados para 1274
em Chinese Academy of Sciences Institutional Repositories Grid Portal
Resumo:
软土地基加固技术是地基工程中一个重要问题,在大量工程实践的基础上,作者采用爆炸法研究了淤泥的排水固结,由于爆炸引起地基的振动加速度与排水关系密切,因此通过实验测量了离爆原近区的加速度,得到加速度随爆炸距离的变化规律;观测分析了爆炸振动过程的加速度波形;通过测定爆炸前后淤泥的工作指标,表明爆炸后短时期内淤泥有含水量有所变化。
Resumo:
发展了一种求解理查森方程的一般有限元算法.该方法采用积分法处理孔隙水压力对时间的导数项,采用集中质量技术处理有限元方程中质量矩阵来保证数值稳定.所采用的质量守恒迭代方法不须改变迭代方式,采用一般的Picard迭代方法.该方法能求解入渗、地下水位瞬变和排水等范围广泛的饱和-非饱和渗流问题.对3个已公开发表具有详细试验数据的算例的模拟表明,该方法对入渗锋、稳定渗流地下水位和非稳定渗流溢出面都模拟很好.Pieard迭代方法效率很高,且无数值振荡发生.
Resumo:
Aim: To study the pharmacokinetics of sifuvirtide, a novel anti-human immunodeficiency virus (HIV) peptide, in monkeys and to compare the inhibitory concentrations of sifuvirtide and enfuvirtide on HIV-1-infected-cell fusion. Methods: Monkeys received 1.2 mg/kg iv or sc of sifuvirtide. An on-line solid-phase extraction procedure combined with liquid chromatography tandem mass spectrometry (SPELC/MS/MS) was established and applied to determine the concentration of sifuvirtide in monkey plasma. A four-I-127 iodinated peptide was used as an internal standard. Fifty percent inhibitory concentration (IC50) of sifuvirtide on cell fusion was determined by co-cultivation assay. Results: The assay was validated with good precision and accuracy. The calibration curve for sifuvirtide in plasma was linear over a range of 4.88-5000 mu g/L, with correlation coefficients above 0.9923. After iv or sc administration, the observed peak concentrations of sifuvirtide were 10626 +/- 2886 mu g/L and 528 +/- 191 mu g/L, and the terminal elimination half-lives (T,12) were 6.3 +/- 0.9 h and 5.5 +/- 1.0 h, respectively. After sc, T-max was 0.25-2 h, and the absolute bioavailability was 49% +/- 13%. Sifuvirtide inhibited the syncytium formation between HIV-1 chronically infected cells and uninfected cells with an IC50 of 0.33 mu g/L. Conclusion: An on-line SPE-LC/MS/MS approach was established for peptide pharmacokinetic studies. Sifuvirtide was rapidly absorbed subcutaneously into the blood circulation. The T-1/2 of sifuvirtide was remarkably longer than that of its analog, enfuvirtide, reported in healthy monkeys and it conferred a long-term plasma concentration level which was higher than its IC50 in vitro.
Resumo:
2003 年1 月, 在广西壮族自治区天峨县红水河水系地下河采集到一批盲鱼标本。经鉴定, 为高原鳅 属Triplophysa 一未经发表的新种。新种天峨高原鳅Triplophysa tianeensis sp1nov1 与个旧盲高原鳅T. gejiuensis 、 石林盲高原鳅T. shilinensis 、阿庐高原鳅T. aluensis 和南丹高原鳅T. nandanensis 相似; 本新种腹鳍末端不达 肛门, 尾鳍分枝鳍条16 , 可进一步与个旧盲高原鳅和石林盲高原鳅(腹鳍末端达到肛门, 尾鳍分枝鳍条14~ 15) 相区别; 本新种背鳍起点位于体之中点、腹鳍起点之后, 肛门紧靠臀鳍起点, 可进一步与阿庐高原鳅(背 鳍起点靠近吻端、位于腹鳍起点之前, 肛门距臀鳍起点仍有一段距离) 相区别。本新种与同分布于红水河水系 的南丹高原鳅Triplophysa nandanensis Lan et al1 较为相似; 但二者区别明显: 新种背鳍分枝鳍条7 、胸鳍分枝鳍 条9 、腹鳍分枝鳍条6 、背鳍外缘平截、背鳍起点位于腹鳍起点之后, 后者背鳍分枝鳍条8 、胸鳍分枝鳍条10~ 11 、腹鳍分枝鳍条7 、背鳍外缘凹入、背鳍起点位于腹鳍起点之前; 此外, 新种的穴居特征更为显著: 眼极度 退化、头长为眼径1618~3218 (2510) 倍、部分个体无色素斑且各鳍无斑点, 而南丹高原鳅眼小、头长为眼径 417~910 (715) 倍、体和头背侧密布云状斑且各鳍均具点状斑。
Resumo:
研究了香溪河库湾春季水华期间(2006年3月3日—4月16日)透明度水层可见光衰减系数KSd的时空特征,分析其与表层水叶绿素a浓度、DOC浓度和透明度Sd的相关关系。结果表明:香溪河库湾春季水华可见光衰减系数KSd时空变异很大;除峡口河段(样点X7—X8)外,可见光衰减系数KSd的变化特征取决于叶绿素a浓度和DOC浓度的时空变化,类似于深水湖泊;除峡口河段(样点X7—X8)外,香溪河库湾可见光衰减系数KSd和透明度之间呈反比的关系具有显著的相关,但它们之间的反比关系因水体叶绿素a和无机悬浮颗粒的空间差异而
Resumo:
Three different types of GaAs metal-semiconductor field effect transistors (MESFET) by employing ion implantation, molecular beam epitaxy (MBE) and low-temperature MBE (LT MBE) techniques respectively were fabricated and studied in detail. The backgating (sidegating) measurement in the dark and in the light were carried out. For the LT MBE-GaAs buffered MESFETs, the output resistance R(d) and the peak transconductance g(m) were measured to be above 50 k Omega and 140 mS/mm, respectively, and the backgating and light sensitivity were eliminated. A theoretical model describing the light sensitivity in these kinds of devices is given. and good agreement with experimental data is reached.
Resumo:
利用脉冲激光沉积(PLD)方法在Si衬底上制备了ZnO单晶体薄膜,并在不同温度下生长了Ag膜作为肖特基电极,研究了Ag与ZnO的接触特性.利用X射线衍射仪、扫描电子显微镜和Ⅰ-Ⅴ测试方法对样品的晶体质量、结构和电学性质进行了分析.结果表明,ZnO薄膜具有高度的c轴择优取向,Ag膜随生长温度的不同的晶体质量有较大差异.样品在室温下的Ⅰ-Ⅴ测试结果表明Ag电极的生长温度对Ag/ZnO接触性能有重要影响.在150℃和200℃生长的Ag电极实现了Ag与ZnO的肖特基接触,电极生长温度低于150℃和高于200℃的样品Ag与ZnO均为欧姆接触.经过分析,肖特基接触的形成依赖于在Ag与ZnO接触界面处形成的p型反型层.
Resumo:
We solve the single mode coupled rate equations by computer, simulate the behavior of a gain switch of an AlGalnP red light semiconductor laser diode, and find the characteristic of FWHM of pulses changing with the amplitude of modulation signal, the bias current, and the modulated frequency. On this basis, we conduct experiments. The experiment results accord with the simulations well.