超声速气流中横向煤油射流的数值模拟

为了对超声速气流中液体横向射流进行数值模拟，采用Eulerian-Lagmngian方法描述气液两相流动现象，用随机轨道模型追踪液滴的运动历程，并考虑气流可压缩性、流场不均匀性及液滴变形对液滴运动的影响，开发了相应的计算程序。计算结果发现，液体射流与气流之间存在着强烈的相互作用，液滴在进入气流中不久就破碎成很小的子液滴，受煤油液雾的影响气流速度、温度急剧下降，同时在喷孔上游出现～道弓形激波。与液雾结构的纹影图像和液雾穿透的实验结果对比显示，数值计算结果基本合理。

Fabrication of microfluidic optical waveguides on glass chips with femtosecond laser pulses

We describe the fabrication of microfluidic channel structures on the surface of a borosilicate glass slide by femtosecond laser direct writing for optical waveguide application. Liquid with a variable refractive index is fed into the microchannel, serving as the core of the waveguide. We demonstrate that either a multimode or a single-mode waveguide can be achieved by controlling the refractive index of the liquid. (C) 2007 Optical Society of America

紫外激光诱导近化学计量比钽酸锂晶体铁电畴反转

对紫外激光诱导近化学计量比钽酸锂晶体铁电畴反转进行了实验研究。波长为351 nm的连续紫外激光被聚焦在近化学计量比钽酸锂晶体的-z表面,同时沿与晶体自发极化相反的方向施加均匀外电场。实验证实紫外激光辐照可以有效地降低晶体畴反转所需的矫顽电场,采用数字全息干涉测量技术检测证实在激光辐照区域实现局域畴反转。研究表明采用紫外激光诱导可以实现对近化学计量比钽酸锂晶体铁电畴反转的局域控制。提出了物理机理的理论分析,认为外电场和激光辐照场的共同作用在晶体内部产生高浓度、大尺寸的缺陷结构,缺陷一定程度上降低畴体成核和畴

Parallel optical negabinary signed-digit computing: algorithm and optical implementation

Negabinary is a component of the positional number system. A complete set of negabinary arithmetic operations are presented, including the basic addition/subtraction logic, the two-step carry-free addition/subtraction algorithm based on negabinary signed-digit (NSD) representation, parallel multiplication, and the fast conversion from NSD to the normal negabinary in the carry-look-ahead mode. All the arithmetic operations can be performed with binary logic. By programming the binary reference bits, addition and subtraction can be realized in parallel with the same binary logic functions. This offers a technique to perform space-variant arithmetic-logic functions with space-invariant instructions. Multiplication can be performed in the tree structure and it is simpler than the modified signed-digit (MSD) counterpart. The parallelism of the algorithms is very suitable for optical implementation. Correspondingly, a general-purpose optical logic system using an electron trapping device is suggested. Various complex logic functions can be performed by programming the illumination of the data arrays without additional temporal latency of the intermediate results. The system can be compact. These properties make the proposed negabinary arithmetic-logic system a strong candidate for future applications in digital optical computing with the development of smart pixel arrays. (C) 1999 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(99)00803-X].

宁蒗保种黑头山羊血液蛋白多态性研究

　采用水平板淀粉胶电泳技术对来自云南保种宁蒗黑头山羊的31 个个 体的39 个基因座位的血液同功酶进行了分析, 结果得到A KP, CES- I, ESD, GO I, M E 和N P 共6 个座位出现多态, 多态座位A KPO , CES- I2, ESDB , GO IA ,M EB 和 N PB 的基因频率较高; 多态座位百分比P = 0. 1538, 平均杂合度H = 0. 0679 ± 0. 0241。本研究首次得到了该羊的遗传多样性特征, 为该羊的保种和利用提供了基础 数据。

白化病的分子机制研究概况

　本文对白化病的症状及分类、白化病各类型的分子机制、人类白化病分子机制研究进展、 白化小鼠分子机制研究进行了综述。

截线抽样法用于鄱阳湖江豚种群数量研究初报

运用截线抽样法调查了在春季4月间鄱阳湖区长江江豚(Neophocaena phocaenoides asiaeorientalis)的种群密度和数量,得出该地区长江江豚种群密度估计值为0.1940头/km2 ,估计数量为388头。探讨了截线抽样法用于浅水型淡水湖泊调查的可行性和有效性以及要注意的问题。

16SrRNA基因序列变异和中国野鲮亚科鱼类单系性研究

形态和分子系统学的研究结果均表明,鲤科中的鲃系是一个单系类群,由鲃亚科、鲤亚科、裂腹鱼亚科和野鲮亚科组成,但它们各自的单系性及相互关系还没有系统发育证据.采用PCR方法获得了27种鱼类的16SrRNA基因序列,其中包括18种野鲮亚科鱼类,代表了中国野鲮亚科13个属.应用邻接法、最大简约法、最大似然法和Bayesian法分别构建其分支系统图.结果表明,野鲮亚科鱼类形成了一个单系类群,并且包括两个主要分支类群:其中一支包含鲮属、缨鱼属和墨头鱼属;另一个支系包括野鲮属、拟缨鱼属、异华鲮属、卷口鱼属、唇鲮鱼属、泉

~(14)C标记1,2,7,8-TCDD在鲤体内分布及代谢的初步研究

利用14C标记1,2,7,8-四氯代二苯并二噁英(1,2,7,8Tetrachloro[U—14C]dibenzodioxin,14C1,2,7,8TCDD)初步研究了其在鲤体内的分布和代谢规律。14C1,2,7,8-TCDD溶解于丙酮/植物油中,腹腔暴露。暴露1、2、4、8、12d后取样,肝脏、胆汁、腹腔脂肪等消化制样后用液闪仪测量放射性活度。肝脏和胆汁内的放射性活度同步变化,都是第8d达到峰值后下降。腹腔脂肪内1—2d放射性明显高于随后取样的样品。肝和腹腔脂肪的分布量之比呈现“S”型变化趋势。暴露4d

Design of Low Power Multi-Standard Active-RC Filter for WLAN and DVB-H

In this paper, a low-power, highly linear, integrated, active-RC filter exhibiting a multi-standard (IEEE 802.11a/b/g and DVB-H) application and bandwidth (3MHz, 4MHz, 9.5MHz) is present. The filter exploits digitally-controlled polysilicon resister banks and an accurate automatic tuning scheme to account for process and temperature variations. The automatic frequency calibration scheme provides better than 3% corner frequency accuracy. The Butterworth filter is design for receiver (WLAN and DVB-H mode) and transmitter (WLAN mode). The filter dissipation is 3.4 mA in RX mode and 2.3 mA (only for one path) in TX mode from 2.85-V supply. The dissipation of calibration consumes 2mA. The circuit has been fabricated in a 0.35um 47-GHz SiGe BiCMOS technology, the receiver and transmitter occupy 0.28-mm(2) and 0.16-mm(2) (calibration circuit excluded), respectively.

CMOS集成电路用Φ150-200mm外延硅材料

报道了Φ150mm CMOS硅外延材料的研究开发及集成电路应用成果，对Φ200mmP/P~-硅外延材料进行了初步探索研究。Φ150mm P/P~+硅外延片实现了批量生产，并成功应用于集成电路生产线，芯片成品率大于80%。硅外延片的参数指标能满足集成电路制造要求。