酚醛树酯的热解动力学模型

建立了一种利用热重峰值分析进行酚醛树酯热解动力学研究的方法,这种方法利用热重谱峰上几个特征点的数据来确定动力学参数.根据酚醛树酯热解DTG曲线的特点,把酚醛树酯的热解过程分解成三个阶段,用峰值分析法对每个反应阶段分别建模,通过三个反应阶段的叠加得到了一个酚醛树酯分阶段热解动力学模型,该模型能够很好地描述酚醛树酯的热解过程. 

Numerical simulation of hypersonic viscous flow around space shuttle with method of diffusion analogy

Hypersonic viscous flow around a space shuttle with M(infinity) = 7, Re = 148000 and angle of attack alpha = 5-degrees is simulated numerically with the special Jacobian matrix splitting technique and simplified diffusion analogy method. With the simplified diffusion analogy method the efficiency of computation and resolution of the shock can be improved.

酚醛树酯的热解动力学模型

建立了一种利用热重峰值分析进行酚醛树酯热解动力学研究的方法,这种方法利用热重谱峰上几个特征点的数据来确定动力学参数.根据酚醛树酯热解DTG曲线的特点,把酚醛树酯的热解过程分解成三个阶段,用峰值分析法对每个反应阶段分别建模,通过三个反应阶段的叠加得到了一个酚醛树酯分阶段热解动力学模型,该模型能够很好地描述酚醛树酯的热解过程.

甲烷团簇纯库仑爆炸的离子平均动能

利用一简单的经典静电模型研究了甲烷团簇纯库仑爆炸情况下产生的离子平均动能。研究表明，甲烷团簇爆炸后离子获得的平均动能和离子的初始平均静电势能的比值，与团簇的尺寸大小无关。这意味着在甲烷团簇纯库仑爆炸近似下，不必使用分子动力学模拟，离子获得的动能可以通过这一比值以及离子的初始静电势能进行估算。给出了不同碳离子价态下的离子平均动能和其初始平均静电势能的比值。

准分子激光等离子体开关控制脉宽研究

利用准分子激光等离子体技术，在紫外预电离XeCl准分子激光器上获得了最短1．58ns的短脉冲激光输出。实验中分析了聚焦到薄膜表面的光束能量密度对所产生的等离子体密度的影响，并对不同等离子体密度及维持时间情况下脉冲压缩效果进行了讨论，给出了激光器谐振腔在稳定腔及非稳腔两种工作方式下的实验结果。激光器在稳定腔工作时，脉宽可压缩至2．87ns采用非稳腔结构时，在脉冲能量不变情况下减小聚焦光斑面积，提高入射到薄膜表面的能量密度，得到了最短1．58ns的短脉冲激光输出。该技术适用于任何其它准分子器件。

Efficient diode-pumped Yb : Gd2SiO5 laser

An efficient diode-pumped laser was demonstrated by using an ytterbium-doped laser crystal, Yb:Gd2SiO5 (Yb:GSO), wherein Yb3+ ions exhibit the largest ground-state splitting among all the ytterbium-doped crystals. The Yb:GSO laser can be operated at a low pumping threshold, and the most efficient laser occurs around 1088 nm since the corresponding emission band has the largest emission cross section and the lowest thermal population. A slope efficiency of 75% was demonstrated for a continuous-wave Yb:GSO laser at 1094 nm, and self-pulsed lasers were achieved within the tunable range of 1091-1105 nm, which are the longest laser wavelengths achieved for Yb3+ lasers. (c) 2006 American Institute of Physics.

Postrelease survival, vertical and horizontal movements, and thermal habitats of five species of pelagic sharks in the central Pacific Ocean

From 2001 to 2006, 71 pop-up satellite archival tags (PSATs) were deployed on five species of pelagic shark (blue shark [Prionace glauca]; shortfin mako [Isurus oxyrinchus]; silky shark [Carcharhinus falciformis]; oceanic whitetip shark [C. longimanus]; and bigeye thresher [Alopias superciliosus]) in the central Pacific Ocean to determine species-specific movement patterns and survival rates after release from longline fishing gear. Only a single postrelease mortality could be unequivocally documented: a male blue shark which succumbed seven days after release. Meta-analysis of published reports and the current study (n=78 reporting PSATs) indicated that the summary effect of postrelease mortality for blue sharks was 15% (95% CI, 8.5–25.1%) and suggested that catch-and-release in longline fisheries can be a viable management tool to protect parental biomass in shark populations. Pelagic sharks displayed species-specific depth and temperature ranges, although with significant individual temporal and spatial variability in vertical movement patterns, which were also punctuated by stochastic events (e.g., El Niño-Southern Oscillation). Pelagic species can be separated into three broad groups based on daytime temperature preferences by using the unweighted pair-group method with arithmetic averaging clustering on a Kolmogorov-Smirnov Dmax distance matrix: 1) epipelagic species (silky and oceanic whitetip sharks), which spent >95% of their time at temperatures within 2°C of sea surface temperature; 2) mesopelagic-I species (blue sharks and shortfin makos, which spent 95% of their time at temperatures from 9.7° to 26.9°C and from 9.4° to 25.0°C, respectively; and 3) mesopelagic-II species (bigeye threshers), which spent 95% of their time at temperatures from 6.7° to 21.2°C. Distinct thermal niche partitioning based on body size and latitude was also evident within epipelagic species.