均匀各向同性湍流的频率波数能量谱

对均匀各向同性湍流的频率波数能量谱进行了初步研究，得出均匀各向同性湍流中能量随时间、空间尺度分布的解析表达式，并运用直接数值模拟的方法对理论预测进行验证．数值结果很好地支持了理论预测：横扫速度是决定频率波数能量谱的特征量．

夹套管端板强度分析探讨

通过对夹套管结构进行分析,建立了端板力学模型,用板理论求解与内管连接处的应力,给出中心点作用力的求解方程,建立了一套各种应力的评判方法,使得端板的强度分析更加方便、科学.

大功率半导体激光器热弛豫时间的测量

根据脉冲工作状态下半导体激光器激射光谱随结温升高而发生红移的原理，提出了一种测试半导体激光器热弛豫时间的新方法——利用调节取样积分器（Boxcar）取样门，测量光信号脉冲内不同时刻的时间分辨光谱。采用此方法对TO封装和厘米-靶条（cm—Bar）阵列的AlGaAs／GaAs半导体激光器的动态热特性进行了测试，得到其热弛豫时间分别为66μs和96μs。

Experimental study of the Talbot effect under femtosecond laser illumination

Experimental results of the Talbot effect of an amplitude grating under femtosecond laser illumination are reported. Compared with Talbot image under continuous wave (CW) illumination, Talbot images under femtosecond laser illumination are different due to the wide spectral bandwidth and the Talbot images are more distorted at longer Talbot distances. The spectrums and the pulsewidths of femtosecond laser pulses are measured with the frequency-resolved optical gating (FROG) apparatus. Experimental results are in good agreement with the theoretical analysis. (c) 2005 Elsevier B.V. All rights reserved.

脉冲压缩光栅光路调节新方法研究

介绍了一种简单而实用的大口径脉冲压缩光栅光路调节方法，有效解决了普通光路调节方法中轴向调节精度不高的问题。首先由全息透镜（光栅）成像公式出发，推导出了该光路调节的基本原理。并从光栅记录系统与光栅衍射波像差的关系，结合初级像差理论推导得出叠栅条纹像差为0．4786λ，大约是光栅衍射波像差（0．25λ）的两倍，利用此关系也可对光栅衍射波像差进行实时监测。从数值模拟结果可知，利用叠栅条纹法调节光路可将光栅波像差减至0．06λ，相应的轴向误差量为0．007mm，可有效提高了轴向调节精度。

黑龙江依兰早第三纪植物群及古气侯分析

本文通过采于黑龙江依兰县达连河露天煤矿的早第三纪植物化石的全面深入研究，借助于叶形、脉形、细脉、角质层共鉴定出植物39科61属78种包括蕨类2种、裸子植物11种、单子叶植物2种、双子叶植物64种，其中有8个新种1个新组合。并通过与类似植物群的对比确定了植物群时代，对地层作了重新划分。 对A段早始新世的植物群分析显示出年均温13.2℃，年温差20℃，有效温度为13.77℃，植被应为常绿阔叶林或富热带性的暖温带常绿阔叶落叶阔叶混交林，沉积盆地为高山谷地。 对B段渐新世的植物群分析显示的古气候年均温11℃，年温差25℃，有效温度13.27℃。植被为暖温带常绿落叶阔叶混交林，沉积环境为狭长河流湖泊，两岸为山地。 通过以上古气候分析，对依兰地区的植物区系演变及温度变迁作了推测，并结合孢粉学、地层学、古昆虫等资料进行了古生态、古地形分析。对被子植物区系的形成演化进行了一些探讨，提出佳依地堑是北极第三系植物群向东南亚扩散迁移的重要通道，对中国植物区系的形成起着极其重要的作用，也是中国植物区系古老、丰富、复杂的原因之一。

抚仙湖无机污染物化学背景值及动物体内致突变性评定

为了比较抚仙湖不同区域的水质及其致突变性, 从抚仙湖周围水域采取7 个样点的水样。用电感 耦合氩等离子发射光谱法对水样中的无机污染物作定性和定量分析。另外使用蝌蚪( B uf o buf o andrewsi) 红细 胞微核试验检测抚仙湖水样的致突变性。结果显示: 禄冲采样点水样带有微核的红细胞率增高, 表明这个点水 样有致突变活性物质。

滇池污染对椭圆背角无齿蚌氨基酸含量的影响

国家科技部和云南省滇池招标课题资助 (项目号DCH010010102)

评价湖泊富营养化的一个综合模型(英文)

湖泊富营养化的评价 ,即确定水体的状态属性 ,实际上是一个将定性问题定量化的多变量的综合决策过程 ,因此 ,对湖泊的富营养化程度进行评价应以综合评价为主 .在综述国内外若干综合评价方法的基础上 ,指出营养状态指数 (TSI)法应可作为湖泊富营养化评价的主要方法 ,因其可对湖泊的营养状态进行连续的数值化分级 ,从而为富营养化机理的定量研究提供坚实基础 .采用层次分析 (AHP)法确定综合评价指标中的权重分配 ,构建一综合评价模型 :TSI =W (Chla)×TSI(Chla) +W (Sd)×TSI(Sd

Seasonal variations in stable isotope ratios of two biomanipulation fishes and seston in a large pen culture in hypereutrophic Meiliang Bay, Lake Taihu

This paper reports on seasonal changes in stable carbon and nitrogen isotope ratios of seston and muscle tissue of silver carp and bighead carp during 2004 and 2005, focusing primarily on the carbon sources and trophic relationships among phytoplankton, zooplankton and silver carp and bighead carp in a large fish pen of Meiliang Bay (Lake Taihu, China). delta C-13 showed a minimal value in March 2005 and a maximal value in August 2005 in seston both inside and outside the pen, whereas delta N-15 of seston showed the minimum in winter and the maximum during algal blooms. A positive correlation between delta C-13 of silver carp and that of seston suggested that temporal variation Of delta C-13 in seston was preserved in fish via the food chain. The differences of delta C-13 among seston, zooplankton and muscle tissue of silver carp and bighead carp ranged only 0.2-1.7%, indicating that plankton production was the primary food source of filter-feeding fishes. According to a mass balance model, we estimated that the contributions of zooplankton to the diets of silver carp and bighead carp were 45.7% and 54.3%, respectively, based on the delta N-15 values of zooplankton and planktivorous fishes. (C) 2007 Elsevier B.V. All rights reserved

Evaluation of soot particles of biomass fuels with endocrine-modulating activity in yeast-based bioassay

Exposure to indoor air pollution (IAP) from the combustion of biomass fuels is an important cause of morbidity and mortality in developing countries. In the work discussed in this paper we evaluated the endocrine activity of soot particles from biomass fuels by using yeast bioassay. These pollutants could have beta-galactosidase activity with a relative potency (RP) about 10(-7)-10(-9) that of estradiol. Soot particles from wood and straw combustion only partially induced beta-galactosidase activity whereas others produced fully inductive activity in the yeast assay system. These pollutants did not have estrogen antagonist and progesterone agonist activity within the defined concentration range. However, these pollutants require 2-4 orders of magnitude higher IC50 to inhibit the activity of progesterone in a similar dose-response manner to mifepristone. We therefore propose that the endocrine activity of some environmental pollutants may be because of inhibition of the progesterone receptor (hPR). GC-MS results showed that substituted polycyclic aromatic hydrocarbon (PAH) compounds, substituted phenolic compounds and derivatives, aromatic carbonyl compounds, and phytosteroids in these soot particles may be mimicking endogenous hormones.

Vertical PIN ultraviolet photodetectors based on 4H-SiC homoepilayers

Vertical PIN ultraviolet photodetectors based on 4H-SiC homoepilayers are presented. The growth of the 4H-SiC homoepilayers was carried out in a LPCVD system. The size of the active area of the photodetector was 300 x 300 mu m(2). The dark and illuminated I-V characteristics were measured at reverse biases from 0 V to 30 V at room temperature. The illuminated current was at least two orders of magnitude higher than the dark current at a bias of below 12 V. The photoresponse was measured from 200 nm to 400 nm at different reverse biases and the peak values of the photo response were located at 3 10 nm. The calculated spectral detectivity D* was shown to be higher than 10(13) cmHz(1/2)/W from 260 to 360 nm with a peak value of 5.9 x 10(13) cmHz(1/2) /W at 310 nm. The peak value of the photoresponse was hundreds of times higher than the response at 400 nm, which showed the device had good visible blind performance. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.