埋设悬跨海底管道的屈曲分析

考虑海床刚度，研究了埋设悬跨海底管道在热膨胀引起的轴向压力下的屈曲问题。传统方法是将悬跨管道简化为两端简支或者两端固支梁来处理。基于欧拉．伯努利梁理论，考虑线弹性海床刚度和轴向压力，建立并求解了埋设段管道和悬跨段管道在自重作用下的四阶常微分方程，获得了两段管道的静挠度和内力的解析公式。通过对静挠度的特性分析，给出了埋设管道段和悬跨管道段的稳定性判断准则。

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.

Polygynous Mating System and Behavioural Reason of Black Crested Gibbon (Nomascus concolor jingdongensis) at Dazhaizi,Mt.Wuliang, Yunnan,China

2003年8月—2005年8月,对无量山大寨子5个黑长臂猿群体的结构和组成进行了观察。当一个群体在早晨鸣叫或依次通过树冠时,记录群体的结构和组成。每个群体都由1个成年雄性、2个成年雌性及其后代组成。2003年8月平均群体大小为6·2只;到2005年8月,平均群体大小发展为6·4只,其中有2个亚成年雄性从出生群迁出,且有3只幼猿出生。在3个群体(G1、G2和G3)中两个成年雌性都成功繁殖了后代。同一群体内两个成年雌性间无攻击或等级行为。2005年4月15日,当一只亚成年雌性进入G3的领域后,两只成年雌性对其进行追逐驱赶,并且干扰其与成年雄性配合进行二重唱,成年雄性没有直接驱赶流浪的亚成年雌性,10天后这只亚成年雌性离开了G3的领域。亚成年雄性经常与群体其他成员保持一定距离,并且在出生地通过独唱练习鸣叫。黑长臂猿可能通过亚成年雄性和雌性的迁出,及成年雌性对外来流浪雌性的驱赶维持这种一夫二妻的群体结构。

高度特化等级裂腹鱼类分子系统发育与生物地理学

分析了分布于青藏高原及其邻近地区23个种和亚种36个群体高度特化等级裂腹鱼类的线粒体DNA细胞色素b序列,重建了系统发育关系.并采用地质隔离事件校正分支时间,估计了主要分支发生时间.结果发现,高度特化等级裂腹鱼类不是单系群,裸鲤属和裸裂尻属也不是单系群.全裸重唇鱼可能是特化类群向高度特化类群演化的过渡类型.高度特化等级裂腹鱼类的系统发育关系总体上反映了水系之间和地质历史的联系,即来自相同和相邻水系的物种通常具有更近的亲缘关系.估计的主要分支发生事件与青藏高原近晚地质时期强烈隆起有很好的一致性,表明高度特化

S7核糖体蛋白基因序列变异及其在低等鲤科鱼类中的系统发育意义

鲤科是世界鱼类中最大的科,有210余属2010种.为研究其系统发育关系需要筛选合适的DNA标记.将S7核糖体蛋白基因用作遗传标记进行鲤科鱼类的系统发育分析.通过PCR方法,扩增了长度为602bp的胭脂鱼以及长度为655～859bp的16种鲤科鱼类的S7基因内含子1序列.序列排列得到925个排列位点,其中信息位点499个,占全部位点的54％.结果表明,鲤科鱼类S7基因内含子1序列具有丰富的信息位点,并且在亲缘关系不同的物种间存在显著的序列差异.基于S7基因内含子1序列的NJ（neighbor-joining

The synthesis of astaxanthin esters, independent of the formation of cysts, highly correlates with the synthesis of fatty acids in Haematococcus pluvialis

The compositions and contents of astaxanthin esters and fatty acids in four types of Haematococcus pluvialis cells were studied by HPLC and GC-MS. Results showed that the synthesis and accumulation of astaxanthin was independent of the formation of cysts, but was highly correlated with the synthesis and accumulation of fatty acids, though it is an well known phenomenon that the accumulation of astaxanthin is usually accompanied by the formation of cyst. The red cysts contain more than 30% of fatty acids, with 81% of the unsaturated fatty acids. Taken together, besides a resource of astaxanthin, H. pluvialis would be a good resource of valuable fatty acids.

Morphological variability between wild populations and inbred stocks of a Chinese minnow, Gobiocypris rarus

Gobiocypris rarus, a small, native cyprinid fish, is currently widely used in research on fish pathology, genetics, toxicology, embryology, and physiology in China. To develop this species as a model laboratory animal, inbred strains have been successfully created. In this study, to explore a method to discriminate inbred strains and evaluate inbreeding effects, morphological variation among three wild populations and three inbred stocks of G. rarus was investigated by the multivariate analysis of eight meristic and 30 morphometric characters. Tiny intraspecific variations in meristic characters were found, but these were not effective for population distinction. Stepwise discriminant analysis and cluster analysis of conventional measures and truss network data showed considerabe divergence among populations, especially between wild populations and inbred stocks. The average discriminant accuracy for all populations was 82.1% based on conventional measures and 86.4% based on truss data, whereas the discriminant accuracy for inbred strains was much higher. These results suggested that multivariate analyses of morphometric characters are an effective method for discriminating inbred strains of G. rarus. Morphological differences between wild populations and inbred strains appear to result from both genetic differences and environmental factors. Thirteen characters, extracted from stepwise discriminant analysis, played important roles in morphological differentiation. These characters were mainly measures related to body depth and head size.

Identification and characterization of a novel splice variant of gonadotropin alpha subunit in the common carp Cyprinus carpio

In this study, an alternative splicing transcript GtH-alpha 291 was identified by RT-PCR, which is 291 nt and exists not only in the pituitary but also in the ovary in common carp Cyprinus carpio. The analysis of GtH-alpha 291 amino acid sequence by the SignalP server predicted that the 'missing segment' might characterize as a signal peptide. In the secretion experiment, GtH-alpha 357 subunit could be secreted out of HeLa cells while GtH-alpha 291 could not, which confirmed the prediction. Co-immunoprecipitation assay proved that GtH-alpha 291 subunit is able to interact with both FSH-beta and LH-beta as GtH-alpha 357 does. This is the first report concerning an alternative splicing transcript of a GtH alpha subunit. Further studies are necessary to elucidate the specific role of this variant in the regulation of gonadal development and sexual maturation. (c) 2007 The Authors.

Passively Q-switched Nd : GdVO4 laser with In0.25Ga0.75As being an output coupler

We report a diode-end-pumped passively Q-switched Nd:GdVO4 laser operating at 1.06 mu m with In0.25Ga0.75As being the saturable absorber as well as an output coupler. Q-switched pulses with a pulse duration of 20 ns, pulse energy 4.2 mu J and pulse repetition rate 200 kHz were produced, corresponding to peak power of 210 W. (c) 2006 Elsevier Ltd. All rights reserved.