Self-adaptive optical systems for long-distance flying optics

The focusing characteristics of long-distance flying optics were studied systemically for TEMmn Gaussian beams. The results show that the ABCD law of parameter q can be extended to Gaussian modes of any order when waist radius w in the imaginary part of parameter q is replaced by Rayleigh range Z(R) of a certain resonator in the equation. The difference between the real focal length and the geometric focal length, defined as Delta f, was calculated for laser applications. A novel self-adaptive optical system was demonstrated for precisely controlling the focusing characteristics of long-distance flying optics, Theoretical analyses and experimental results were consistent. (c) 2006 Optical Society of America.

Avoidant Learning Ability in Free Flying Housefly (Aldrichina grahami)by Electric Shock

下载PDF阅读器研究证实:蜜蜂和果蝇具有良好的学习记忆能力.利用自主改良的研究装置对另一种具有强大生存本能的双翅目昆虫--巨尾阿丽蝇(Aldrichina grahami)在自由状态下电击同避学习能力进行研究.结果表明,巨尾阿丽蝇具有良好的学习记忆能力,因为当刺激电压范围为5V到45V时,观察到巨尾阿丽蝇有显著的回避电刺激行为,而当电压达到60V时会受到明显伤害.由此推测,巨尾阿丽蝇适合作为神经系统研究的动物模型.该实验所采用的实验范例较以往有所改进,适合作为自由状态下研究昆虫的工具.

Predation on giant flying squirrels (Petaurista philippensis) by black crested gibbons (Nomascus concolor jingdongensis) at Mt. Wuliang, Yunnan, China

Predation on vertebrates is infrequent in gibbons. In a 14-month field study of the central Yunnan black crested gibbon (Nomascus concolor jingdongensis) at Mt. Wuliang, Yunnan, China, we observed gibbons attacking, killing and eating giant flying squirre

Molecular phylogeny and biogeography of woolly flying squirrel (Rodentia : Sciuridae), inferred from mitochondrial cytochrome b gene sequences

To investigate the genetic diversity between the populations of woolly flying squirrels (Eupetaurus) from the eastern and western extremes of the Himalayas, partial mitochondrial cytochrome b gene sequences (390-810bp) that were determined from the museum specimens were analyzed using maximum parsimony (MP) and maximum likelihood (ML) methods. The molecular data reveal that the two specimens that were collected in northwestern Yunnan (China) are members of the genus Eupetaurus. Reconstructed phylogenetic relationships show that the populations of Eupetaurus in the eastern and western extremes of the Himalayas are two distinct species with significant genetic differences (12%) and diverged about 10.8 million years ago. Eupetaurus is significantly different from Petaurista and Pteromys. The level of estimated pairwise-sequence divergence observed between Eupetaurus and Petaurista or Pteromys is greater than that observed between Eupetaurus and Trogopterus, Belomys, Glaucomys, or Hylopetes. Considering the divergence time of the two Eupetaurus groups, the glaciations and the uplift of the Himalayas and Qinghai-Tibet plateau during the Pliocene-Pleistocene period might be the major factors affecting the present distribution of Eupetaurus along the Himalayas. (C) 2004 Elsevier Inc. All rights reserved.

A bistable, self-latching inverter by the monolithic integration of resonant tunnelling diode and high electron mobility transistor

This paper reports that the structures of AlGaAs/InGaAs high electron mobility transistor (HEMT) and AlAs/GaAs resonant tunnelling diode (RTD) are epitaxially grown by molecular beam epitaxy ( MBE) in turn on a GaAs substrate. An Al0.24Ga0.76As chair barrier layer, which is grown adjacent to the top AlAs barrier, helps to reduce the valley current of RTD. The peak-to-valley current ratio of fabricated RTD is 4.8 and the transconductance for the 1-mu m gate HEMT is 125mS/mm. A static inverter which consists of two RTDs and a HEMT is designed and fabricated. Unlike a conventional CMOS inverter, the novel inverter exhibits self-latching property.

A high-performance Si-based MOS electrooptic phase modulator with a shunt-capacitor configuration

A novel Si-based metal-oxide-semiconductor (MOS) electrooptic phase modulator including two shunt oxide layer capacitors integrated on a silicon-on-insulator (SOI) waveguide is simulated and analyzed. The refractive index near the two gate oxide layers is modified by the free carrier dispersion effect induced by applying a positive bias on the electrodes. The theoretical calculation of free carrier distribution coupled with optical guided mode propagation characteristics has been carried out. The influence of the structure parameters such as the width and the doping level of the active region are analyzed. A half-wave voltage V-pi = 4 V is demonstrated with an 8-mm active region length and a 4-mu m width of an inner rib under an accumulation mode. When decreasing the inner rib width to 1 mu m, the phase modulation efficiency is even higher, and the rise and fall times reach 50 and 40 ps, respectively, with a 1.0 x 10(17) cm(-3) doping level in the active region.

On the design and simulation of high speed electro-optic modulator based on SOI waveguide MOS dual capacitor structure

zhangdi于2010-03-29批量导入

Flying lemurs – The 'flying tree shrews'? Molecular cytogenetic evidence for a Scandentia-Dermoptera sister clade

Background: Flying lemurs or Colugos (order Dermoptera) represent an ancient mammalian lineage that contains only two extant species. Although molecular evidence strongly supports that the orders Dermoptera, Scandentia, Lagomorpha, Rodentia and Primates form a superordinal clade called Supraprimates (or Euarchontoglires), the phylogenetic placement of Dermoptera within Supraprimates remains ambiguous. Results: To search for cytogenetic signatures that could help to clarify the evolutionary affinities within this superordinal group, we have established a genome-wide comparative map between human and the Malayan flying lemur (Galeopterus variegatus) by reciprocal chromosome painting using both human and G. variegatus chromosome-specific probes. The 22 human autosomal paints and the X chromosome paint defined 44 homologous segments in the G. variegatus genome. A putative inversion on GVA 11 was revealed by the hybridization patterns of human chromosome probes 16 and 19. Fifteen associations of human chromosome segments (HSA) were detected in the G. variegatus genome: HSA1/3, 1/10, 2/21, 3/ 21, 4/8, 4/18, 7/15, 7/16, 7/19, 10/16, 12/22 (twice), 14/15, 16/19 (twice). Reverse painting of G. variegatus chromosome-specific paints onto human chromosomes confirmed the above results, and defined the origin of the homologous human chromosomal segments in these associations. In total, G. variegatus paints revealed 49 homologous chromosomal segments in the HSA genome. Conclusion: Comparative analysis of our map with published maps from representative species of other placental orders, including Scandentia, Primates, Lagomorpha and Rodentia, suggests a signature rearrangement (HSA2q/21 association) that links Scandentia and Dermoptera to one sister clade. Our results thus provide new evidence for the hypothesis that Scandentia and Dermoptera have a closer phylogenetic relationship to each other than either of them has to Primates.

中国松鼠科 Sciuridae (Non-flying squirrels) 动物的分类和分布及系统发育研究

松鼠科隶属于哺乳纲、啮齿目，是一类世界广布性动物，全世界共计36 属 234 种。本文通过形态分析及分子生物学方法，研究了我国松鼠科动物的分类及 系统发育关系，内容包括以下两个方面： 一、中国松鼠科动物的分类 本研究查看了中科院昆明动物研究所、中科院动物研究所、云南大学、四川 省林业科学研究院、四川大学、陕西师范大学、陕西动物研究所、西北大学、上 海自然历史博物馆、广东昆虫所馆藏该科各类群标本。同时，结合相关文献，对 各类群的外形特征进行了详细的描述和系统分类整理，我国共计10 属34 种。测 取可量性状数据共计20800 个（完整头骨共计1300 号），而且还运用多变量及单 变量分析方法进行数据分析，对部分类群的种下分类结果进行分析：1.探讨了分 布于中国境内的明纹花鼠（Tamiops mcclellandii）3 亚种的有效性。2.研究了 隐纹花鼠（Tamiops swinhoei）在中国的分化并描记了分布于四川马尔康地区的 隐纹花鼠为一新亚种（Tamiops swinhoei markamensis）。3.描记了分布于云南 省东北部昭通地区的赤腹松鼠为一新亚种：昭通亚种（Callosciurus erythraeus zhaotongensis）。4. 提出了分布于云南省无量山区的泊氏长吻松鼠为一新亚种： 无量山亚种（Dremomys pernyi wuliangshanensis）。 二、中国松鼠科动物的系统发育研究 2004－2005 年相继到滇西北高黎贡山、香格里拉，滇西南临沧地区，滇东 南马关、麻栗坡、富宁，滇东北昭通地区进行标本采集，基本收集到我国南方松 鼠科属、种样品进行分子生物学研究。 1.中国松鼠科动物各属的系统发育关系 在分析线粒体细胞色数b 基因（1040bp）序列的基础上，运用贝叶斯法 （Bayesian phylogenetic reconstruction approaches）、最简约法（Maximum parsimony method）、邻接法（Neighbor Joining method）构建中国松鼠科动物 所有属间系统发育树。结果表明：所分析的10 属分别聚集为3 群，巨松鼠属Ratufa单独成为一群，丽松鼠属Callosciurus、长吻松鼠属Dremomys、花松鼠属 Tamiops 以及线松鼠属Menetes 成为一群，松鼠属Sciurus、岩松鼠属 Sciurotamias、花鼠属Tamias、旱獭属Marmota 以及黄鼠属Spermophilus 成 为一群。在此基础上我们进一步探讨了中国松鼠科动物的分化与环境变化的关 系。 2.长吻松鼠属的系统发育关系 在分析线粒体细胞色数b 基因（378bp）序列的基础上，我们重建了长吻松 鼠属内5 个类群间的系统发育关系，结合对5 类群外部形态特征的详细比较，我 们探讨并论证了红腿长吻松鼠、橙喉长吻松鼠作为种的地位的有效性，同时论证 了该属内泊氏长吻松鼠最早分化，其次为橙腹长吻松鼠，第三是红腿长吻松鼠， 红颊长吻松鼠和橙喉长吻松鼠是最后分化的类群。

A High-Performance Silicon Electro-Optic Phase Modulator with a Triple MOS Capacitor

We propose and analyze a novel Si-based electro-optic modulator with an improved metal-oxide-semiconductor (MOS) capacitor configuration integrated into silicon-on-insulator (SOI).Three gate-oxide layers embedded in the silicon waveguide constitute a triple MOS capacitor structure,which boosts the modulation efficiency compared with a single MOS capacitor.The simulation results demonstrate that the VπLπ product is 2.4V·cm.The rise time and fall time of the proposed device are calculated to be 80 and 40ps from the transient response curve,respectively,indicating a bandwidth of 8GHz.The phase shift efficiency and bandwidth can be enhanced by rib width scaling.

Design and simulation of charge sensitive preamplifier with CMOS FET implemented as feedback capacitor C-fp

In this paper, to design a new preamplifier for optimum performances with charged-particle or heavy-ion detectors, the CMOS FET is implemented as a feedback capacitor C-fp, so that the entire system should be built only with MOSFET. This work is a revolution design because to realize an ASIC for a preamplifier circuit, the capacitor will also be included. We succeed after a simulation to maintain a rise time less than 3 ns, the output resistance less than 94 Omega and the linearity almost good.

POLYANILINE ELECTROLYTIC CAPACITOR

Aluminum solid electrolytic capacitors with polyaniline doped with inorganic and organic acids as counterelectrode were fabricated, their properties were studied.

航天器稀疏编队飞行的概念及其设计方法

提出了航天器稀疏编队飞行的概念及其设计方法，阐明了它与通常的紧密编队飞行的区别及其在应用上的前景。采用了一个比Hill解更为广泛的新公式来设计稀疏编队，并列举了若干稀疏编队的阵形。当各航天器距离很近时，该公式自然退化为与Hill解相同的形式。通过与Hill解的设计相比较，表明了新公式用于稀疏编队设计的优越性。

大偏心率远距离航天器编队飞行设计

为寻求适用于大偏心率远距离航天器编队设计的方法，摒弃了简化航天器相对运动非线性微分方程的传统思路，致力于简化该微分方程的解析解。首先，在同周期假定前提下，由运动学得到了椭圆轨道航天器相对于圆轨道航天器运动的封闭解析解，然后将其展开成傅立叶级数，证明了在特定条件下，单倍频项是最主要的，从而导出了编队飞行设计的新公式。最后以空间圆形编队设计为例，阐明了利用新公式进行编队设计的步骤，并用精确的数值计算验证了设计结果的正确性。与C—W方法和一般轨道参数设计方法相比，推导过程中并未采用小偏心率近距离假定，因此导出的新公式可适用于大偏心率远距离航天器的编队设计。