Abel Inversion of Axially-Symmetric Shock Wave Flows

Finite-fringe interferograms produced for axisymmetric shock wave flows are analyzed by Fourier transform fringe analysis and an Abel inversion method to produce density field data for the validation of numerical models. For the Abel inversion process, we use basis functions to model phase data from axially-symmetric shock wave structure. Steady and unsteady flow problems are studied, and compared with numerical simulations. Good agreement between theoretical and experimental results is obtained when one set of basis functions is used during the inversion process, but the shock front is smeared when another is used. This is because each function in the second set of basis functions is infinitely differentiable, making them poorly-suited to the modelling of a step function as is required in the representation of a shock wave.

电子束物理气相沉积钇钛合金薄膜的组分和厚度分布

大面积薄膜的组分和厚度分布是实际工艺中最为关心的问题之一.利用实验和直接模拟Monte Carlo(DSMC)方法,分别研究了双电子束和三电子束物理气相沉积(EBPVD)中,钇和钛蒸气原子的三维低密度、非平衡射流,获得了它们在100和150mm单晶硅基片表面的沉积厚度和组分的分布.DSMC结果与钇和钛的蒸发速率的石英晶振探头原位测量值,沉积薄膜厚度分布的台阶仪和Rutherford背散射仪的测量数据,沉积薄膜组分分布的Rutherford背散射仪和电感耦合等离子体原子发射光谱仪测量值,均相符甚好.这表明通过DSMC方法与精细测量相结合,可在原子水平上实现EBPVD输运工艺的定量预测和设计。

Analysis of beam-quality degradation in nonlinear frequency conversion

Based on the ripple transfers of electric-field amplitude and phase in frequency tripling, simple formulas are derived for the harmonic laser's beam-quality factor M-3omega(2), with an arbitrary fundamental incidence to ideal nonlinear crystals. Whereas the harmonic beam's quality is generally degraded, the beam's divergence is similar to that of the fundamental after nonlinear frequency conversion. For practical crystals with periodic surface ripples that are caused by their machining, a multiorder diffractive model is presented with which the focusing properties of harmonic beams can be studied. Predictions of the theories are shown to be in excellent agreement with full numerical simulations. (C) 2002 Optical Society of America.

光学薄膜的分层界面散射模型

提出了一种计算光学介质膜系表面总积分散射（TIS）的理论模型。该模型认为，介质膜系粗糙的膜层界面和表面为微观结构不均匀的微薄过渡区；过渡区可用折射率为不同常量的层数足够多的均匀子层来代替，同时这些均匀子层的折射率变化满足指数函数的分布规律。利用矩阵法对积分散射的表达式进行了推导。对于电子束蒸发方法在K9玻璃上沉积的ZrO2单层膜，分层界面散射模型对积分散射的理论计算值要比非相关表面散射模型的计算值更加符合总积分散射仪的实验测量结果。

小鼠双尾C蛋白Bicc1多克隆抗体的制备及细胞内定位的初步研究

目的:制备小鼠双尾C蛋白Bicc1的多克隆抗体并确定其在细胞内定位.方法:根据生物信息学分析结果, PCR扩增小鼠Bicc1编码61E-199A的cDNA片段.将该片段克隆到GST融合蛋白表达载体上, 在IPTG诱导下产生Bicc1-N抗原.纯化目的蛋白并制备兔抗Bicc1蛋白多克隆抗体.Western blot鉴定抗体特异性, 并以间接免疫荧光法初步分析该蛋白在细胞内定位.结果:成功构建Bicc1-N片段原核表达载体, 在大肠杆菌中实现可溶性表达, 制备小鼠Bicc1蛋白的多克隆抗体, 并证实该蛋白主要表达于细胞质内.结论:成功制备了高效价并特异的兔抗Bicc1多克隆抗体, 为进一步研究Bicc1基因产物的生物功能奠定了基础.

萤火虫生物学特性及其应用研究

介绍了萤火虫生活史和生活习性、发光机制和发光的作用以及萤火虫荧光素酶的性质、结构和特点,并阐述了萤火虫的应用领域,指出萤火虫是一种非常有利用价值的资源昆虫,人们应该珍惜并保护这种昆虫。

Characterization of a new bradykinin-potentiating peptide (TmF) from Trimeresurus mucrosquamatus

A novel bradykinin-potentiating peptide (BPP), designated as TmF, has been purified to homogeneity from the venom of Trimeresurus mucrosquamatus by 70% cold methanol extraction, Sephadex G-15 gel filtration and reverse-phase high performance liquid chromatography (RP-HPLC). The amino acid sequence of TmF was determined to be pGlu-Gly-Arg-Pro-Leu-Gly-Pro-Pro-Ile-Pro-Pro (pGlu denotes pyroglutamic acid), which shared high homology with other BPPs. The molecular mass of TmF was 1.1107 kD as determinated by electrospray ionization-mass spectrometry (ESI-MS), which was in accordance with the calculated value of 1.1106 kD. The potentiating "unit" of TmF to bradykinin-induced (BK-induced) contraction on the guinea-pig ileum in vitro was (1.13 +/- 0.3) unit (mg/L), and TmF (5.0 x 10(-4) mg/kg) increased the pressure-lowering-effect of bradykinin (5.0 x 10(-5) mg/kg) with approximate descent value of (14 +/- 2) mmHg. In addition, TmF inhibited the conversion of angiotensin I to angiotensin 11, 2 x 10(-3) mg of TmF caused 50% inhibition (IC50) of angiotensin-converting enzyme (ACE) hydrolyzing activity to bradykinin.

丝状绿藻腐烂过程对水质和沉水植物黑藻生长的影响实验研究

从野外采集沉水植物黑藻种植于120L的塑料桶内,然后采集丝状绿藻放在培养黑藻的桶内。设种植黑藻而不放入丝状绿藻的桶为对照。由于夏季高温和强光,丝状绿藻在数天内会逐渐腐烂。研究发现,在丝状绿藻腐烂过程中,水体的溶解氧(DO)、pH值、水下光强度与水面光强度的比值均比对照组大大降低,尤其是溶解氧,有时甚至下降为零。而水体的温度、总氮(TN)、总磷(TP)和高锰酸钾指数(CODMn)在丝状绿藻腐烂过程中则上升,后3个指标大大高于对照。有丝状绿藻处理的试验组,随着丝状绿藻的腐烂,沉水植物黑藻亦慢慢腐烂,最后消失。

Identification and characterization of a novel gene differentially expressed in zebrafish cross-subfamily cloned embryos

m Background: Cross-species nuclear transfer has been shown to be a potent approach to retain the genetic viability of a certain species near extinction. However, most embryos produced by cross-species nuclear transfer were compromised because that they were unable to develop to later stages. Gene expression analysis of cross-species cloned embryos will yield new insights into the regulatory mechanisms involved in cross-species nuclear transfer and embryonic development. Results: A novel gene, K31, was identified as an up-regulated gene in fish cross-subfamily cloned embryos using SSH approach and RACE method. K31 complete cDNA sequence is 1106 base pairs (bp) in length, with a 342 bp open reading frame (ORF) encoding a putative protein of 113 amino acids (aa). Comparative analysis revealed no homologous known gene in zebrafish and other species database. K31 protein contains a putative transmembrane helix and five putative phosphorylation sites but without a signal peptide. Expression pattern analysis by real time RT-PCR and whole-mount in situ hybridization (WISH) shows that it has the characteristics of constitutively expressed gene. Sub-cellular localization assay shows that K31 protein can not penetrate the nuclei. Interestingly, over-expression of K31 gene can cause lethality in the epithelioma papulosum cyprinid (EPC) cells in cell culture, which gave hint to the inefficient reprogramming events occurred in cloned embryos. Conclusion: Taken together, our findings indicated that K31 gene is a novel gene differentially expressed in fish cross-subfamily cloned embryos and over-expression of K31 gene can cause lethality of cultured fish cells. To our knowledge, this is the first report on the determination of novel genes involved in nucleo-cytoplasmic interaction of fish cross-subfamily cloned embryos.

Induction and preliminary characterization of a novel halophage SNJ1 from lysogenic Natrinema sp F5

Halophage SNJ1 was induced with mitomycin C from Natrinema sp. strain F5. The phage produces plaques on Natrinema sp. strain J7 only. The phage has a head of about 67 nm in diameter and a tail of 570 nm in length and belongs morphologically to the family Siphoviridae. The phage is strongly salt dependent; NaCl concentration affects the integrity of SNJ1, phage adsorption, and plaque formation. The optimal NaCl concentration for phage adsorption and plaque formation is 30% and 25%, respectively.

Stochastic resonance in quantum-well semiconductor lasers

The quantum well (QW) semiconductor lasers have become main optical sources for optical fibre communication systems because of their higher modulation speed, broader modulation bandwidth and better temperature characteristics. In order to improve the quality of direct-modulation by means of the stochastic resonance (SR) mechanism in QW semiconductor lasers, we investigate the behaviour of the SR in direct-modulated QW semiconductor laser systems. Considering the cross-correlated carrier noise and photon noise, we calculate the power spectrum of the photon density and the signal-to-noise ratio (SNR) of the direct-modulated laser system by using the linear approximation method. The results indicate that the SR always appears in the dependence of the SNR on the bias current density, and is strongly affected by the cross-correlation coefficient of the carrier and photon noises, the frequency of modulation signal, and the photon lifetime in the laser cavity.

Whispering-gallery-likel modes in square resonators

The mode frequencies and field distributions of whispering-gallery (WG)-like modes of square resonators are obtained analytically, which agree very well with the numerical results calculated by the FDTD technique and Pade approximation method. In the analysis, a perfect electric wall for the transverse magnetic mode or perfect magnetic wall for the transverse electric mode is assumed at the diagonals of the square resonators, which not only provides the transverse mode confinement, but also requires the longitudinal mode number to be an even integer. The WG-like modes of square resonators are nondegenerate modes with high-quality factors, which make them suitable for fabricating single-mode low-threshold semiconductor microcavity lasers.