Stability and Bifurcation Bahaviour of Electrostatic Torsional NEMS Varactor Influenced by Dispersion Forces

The influences of Casimir and van der Waals forces on the nano-electromechanical systems (NEMS) electrostatic torsional varactor are studied. A one degree of freedom, the torsional angle, is adopted, and the bifurcation behaviour of the NEMS torsional varactor is investigated. There are two bifurcation points, one of which is a Hopf bifurcation point and the other is an unstable saddle point. The phase portraits are also drawn, in which periodic orbits are around the Hopf bifurcation point, but the periodic orbit will break into a homoclinic orbit when meeting the unstable saddle point.

循环载荷下非凝聚土本构方程的数值计算

循环荷载下非凝聚土弹－塑性本构主程的数值计算包含了许我离散化，这将导致偏离屈服面的问题，弹塑性加载增量所预言的应力状态在屈面上，这样，偏离将积累起来，所以在每一步加截增量后进行修正，以确保应力仍落在屈服面上就显得十分重要了。

Phase-sensitive atom localization in a loop Lambda-system

The behaviour of the Lambda-system has been studied theoretically in the context of atom localization. In addition to the probe field and the standing wave driving field, a microwave field is introduced to couple the two lower states, and as a result our Lambda-system forms a closed loop. Therefore phase-sensitive atom localization is expected. Indeed by appropriate choice of the relative phase between three fields, an improvement by a factor of 2 has been found in the detection probability of atoms within the sub-wavelength domain of the standing wave. The effect of other parameters is also investigated.

Pondermotive shift of photoelectron spectra in intense laser field

In a recent experimental work on the excess photon detachment (EPD) of H- ions [Phys. Rev. Lett. 87 (2001) 243001] it has been found that the ponderomotive shift of each EPD peak increases with the order of the EPD channel. By using a nonperturbative quantum scattering theory, we obtain the kinetic energy spectra for the differential detachment rate along the laser polarization for several laser intensities. It is demonstrated that higher order EPD peaks are produced mainly at relatively higher laser intensities. By calculating the overall EPD spectra with varying laser intensities, it is found that the ponderomotive shift of each EPD peak increases with the order of the EPD channel. Our calculations are in good agreement with the experimental observation. It is found that different EPD channels occur mainly when the laser field reaches some values, thus the intensity distribution of the laser field is responsible for the varying ponderomotive shifts.

Methods for removal of spurious reflection effect on phase-shifting interferometry

Spurious reflection is one of the troublesome problems in phase-shifting interferometry. This paper deals with the problem on the basis of a two-run-times-two-frame phase-shift algorithm, in which the phase shifts are shared out between the reference beam and the object beam. The effect of spurious reflection on phase measurement is investigated; two simple methods for removal of the effect are presented and each needs only six interferograms. Two other solutions to the spurious reflection problem are also reviewed. The simulation results obtained using these four solutions are compared. The influence of a mix of phase-shifter miscalibration and spurious reflection on phase measurement is also discussed.

Time response of optical switching properties of Sb thin films under focused laser pulses

The time response of optical switching properties of Sb thin films under focused laser pulses is investigated. The results show that the response course can be divided into onset, opening, and closing stages. Formulas for their lengths are given. The onset and opening times decrease with increasing pumping light power density. The closing time is about 150 ns. For optical memory, if the power density of the readout and recording lasers changes from 5 x 10(9) to 15 x 10(9) W/m(2), the onset time changes from 2.5 to 0.30 mus, and the opening time is on the nanosecond scale. (C) 2003 Society of Photo-Optical Instrumentation Engineers.

冷杉属的系统学研究

冷杉属是松科中的第二大属，在北半球有着广泛的分布区，从温带的高纬度地带到亚热带（偶达热带地区）的山地，呈间断不连续的分布。虽然一些学者曾对冷杉属进行过大量的分类学和系统学研究，但该属复杂的变异式样至今仍困扰着植物系统学家们。本论文是在腊叶标本和野外实地调查的基础上，从形态学、解剖学、分子系统学和植物地理学等方面进行分类学和系统发育的分析研究。现得到以下初步结果。1.对冷杉属叶角质层内表面胞间凸缘的研究结果表明，可以分为4种类型： 1. 弯曲且发达的单凸缘;2直且发达的单凸缘;3不发达的单凸缘;4双桥型凸缘。分布于欧洲和亚洲的绝大部分种类都是弯曲且发达的单凸缘类型（日本一种除外），而分布于北美的种类则具有四种不同的类型。 2. 叶横切面的研究结果表明皮下层细胞的发育状况和树脂道的位置与大小在Sect. Balsamea中稳定，皮下层细胞的缺失和不发育、树脂道大且中生在该属中可能反映原始状态。 3. 本研究首次发现nrDNA ITS的长度在属下有较大的变异，变异幅度1700 bp-2500 bp，分析得出引起这一变异的主要原因是由于ITS1中有以GGCCACCCTAGTC为核心数目不等的重复序列的存在，并讨论了ITS长度的变异在冷杉属和松科系统演化中的意义。 4. nrDNA ITS的RFLP分析结果和5种冷杉的ITS序列分析结果（以Keteleeria davidiana为外类群）表明A. bracteata与Sect. Balsamea总是聚在一起，亲缘最近;A. kawakamii应属于Sect. Momi。 5. 地理分布和系统发育分析的研究结果表明，冷杉属的多样性中心在北美西南部、而种类分布最大多的地区为东亚、种群分化最强烈的地区为我国的横断山脉。根据冷杉属的系统发育、化石资料和现代冷杉属的地理分布格局，冷杉属可能起源于白垩纪的高纬度地带。 6. 结合ITS RFLP和ITS序列的分支分析结果以及某些形态特征和地理分布资料，重建属下分类系统，将冷杉属分为8组2亚组。探讨了各组间的亲缘关系，认为Sect. Balsamea是冷杉属中的原始类群，Sect. Balsamea是与Sect. Balsamea亲缘最近，形态上十分特化的类群。来自ITS的分析结果为摒属下亚属的划分和将A. kawakamii自Sect. Balsamea中移出，放入Sect. Momi中提供了强有力的证据。经过标本和文献考证，综合各方面的资料，本文对冷杉属进行了全面系统的分类学修订，包括44种17变种1亚种，系统排列如下： 组1. 树脂冷杉组Sect. 1. Balsamea Engelmann。该组包括8种4变种：Abies balsamea, A. lasiocarpa, A. sibirica, A. sachalinensis, A. fraseri, A. koreana, A. nephrolepis, A. veitchii, A. bracteata。 组3. 日本冷杉组Sect. 3. Momi Franco。 亚组1.日本冷杉亚组Subsect. 1. Firmae (Franco) Farjon et Rushforth。该亚组包括6种3变种：A.holophylla, A. homolepis, A. firma, A. beshanzuensis, A. chensiensis, A. pindrow, A. beshanzuensis var. ziyuanensis, A. chensiensis var. ernestii, A. chensiensis var. salouenensis。 亚组2. 鳞皮冷杉亚组Subsect. 2. Squamatae E. Murray。该亚组包括12种6变种：A squamata, A. delavayi, A. nukiangensis, A. recurvata, A. spectabilis, A. mariesii, A. kawakamii, A. forrestii, A. fargesii, A. fansipanensis, A. fanjingshanensis, A. yuanbaoshanensis, A. delavayi var. fabri, A. delavayi var. motuoensis, A. spectabilis var. densa, A. forrestii var. georgei, A. forrestii var. ferreana, A. fargesii var. faxoniana。 组4. 冷杉组Sect. 4. Abies。该组包括7种1变种1亚种：A. alba, A. cephalonica, A. nordmanniana, A. nebrodensis, A. cilicica, A. pinsapo, A. numidica, A. nordamanniana ssp. equitrojani, A. pinsapo var. marocana。 组5. 太平洋冷杉组成Sect. 5. Amabiles (Matzenko) Farjon et Rushforth。该组仅一种：A. amabilis。 组6. 高贵冷杉组Sect. 6. Nobilis Engelmann。该组有2种1变种：A. procera, A. magnifica, A. magnifica var. shastensis。 组7. 大冷杉组成Sect. 7. Grandes Engelmann, emend. Farjon et Rushforth。该组包括4种2变种：A. concolor, A. grandis, A. durangensis, A. guatemalensis, A. concolor var. lowiana, A. durangensis var. coahuilensis。 组8. 墨西哥冷杉组Sect. 8. Oiamel Franco, emend. Farjon et Rushforth。该组包括A. religiosa, A. vejarii, A. vejari var. mexicana, A. hickelii

天山不同海拔高度下长鳞红景天种群遗传多样性分析

长鳞红景天（Rhodiola gelida）属景天科红景天属，多年生草本。主要分布在我国新疆中部天山。在天山一号冰川观测试验站附近的高寒草甸上，从海拔3850m~4010m均有长鳞红景天分布。长鳞红景天是一种重要的药用植物，但目前尚未见到有关其遗传多样性方面的研究报道。本文利用相关序列扩增多态性（sequence-related amplified polymorphism，SRAP）分子标记技术，对新疆天山不同海拔高度3个长鳞红景天种群的遗传多样性，种群内及种群间的遗传变异进行研究，为有效保护和合理利用长鳞红景天物种资源提供理论依据。主要结果如下： （1）基于CTAB法，建立了适合长鳞红景天的DNA提取方法，获得的DNA经琼脂糖电泳和紫外分析仪检测，浓度和质量均较高。该法有利于去除长鳞红景天植物材料中多糖、多酚类等物质，获得的高质量基因组DNA能够满足后续的PCR实验要求。 （2）采用正交实验对影响长鳞红景天SRAP-PCR反应的4个主要因素（Taq酶用量、Mg2+浓度、dNTP浓度、引物浓度）进行优化试验，选出这4个因素的最佳水平组合，建立了长鳞红景天SRAP-PCR最佳反应体系。同时，根据最佳体系筛选出扩增稳定、多态性丰富的SRAP引物。通过梯度PCR确定引物的最佳退火温度，得到了适合长鳞红景天SRAP-PCR反应的最佳扩增程序。 （3）对20对SRAP引物的扩增结果进行统计分析显示：长鳞红景天物种水平的多态位点百分率(P)为96.00 %，Shannon信息指数(I)为0.4484、基因多样性指数(H)为0.2922，表现出较高的遗传多样性水平；在海拔梯度上，长鳞红景天各种群间的遗传多样性水平有一定差异，但没有呈现规律性的变化；AMOVA分子变异分析显示，在总遗传变异中24.76 % 的变异存在于种群间，75.24 % 的变异存在于种群内，种群间的基因分化系数(Gst)为0.1749，表明3个长鳞红景天种群的变异主要存在于种群内，但种群间也出现了一定程度的遗传分化；长鳞红景天3个种群间的基因流为2.3595，遗传距离平均值为0.0981（变化范围：0.0768 ～0.1196），遗传距离较近，说明海拔高度对长鳞红景天的地理隔离较小；相关性分析表明长鳞红景天种群的遗传多样性与各生态因子的相关性均不显著。

鬼臼类化合物及其用途

本发明公开一类新型的鬼臼类化合物，以及这类化合物的用途和这类化合物的制备方法。

High rate of chimeric gene origination by retroposition in plant genomes

Retroposition is widely found to play essential roles in origination of new mammalian and other animal genes. However, the scarcity of retrogenes in plants has led to the assumption that plant genomes rarely evolve new gene duplicates by retroposition, de

一种尖吻蝮蛇毒凝血酶及其生产方法

本发明经阴离子交换剂柱层析法分离纯化及快速蛋白纯化工作站程序再纯化，从我国特产尖吻蝮(Agkistrodon acutus)蛇毒中得到纯度在97％以上的尖吻蝮蛇毒凝血酶Ⅱ；经测定，该酶Ⅱ由A、B两个亚基(链)组成，其中，A亚基含有125个氨基酸，B亚基含有123个氨基酸；与现有蛇毒凝血酶(如Reptilase)相比，它是一个全新的新型酶止血剂。经药理、毒理、药代等研究表明，它是一个见效快，副作用小的、安全有效的新型止血剂。

饥饿和饱食状态下丰鲤与其亲本的活动水平和活动节律

使用Videomex-V影像运动监视系统全天监测丰鲤(Cyprinus carpiovar.Xingguo♀×Cyprinus carpiovar.mirror splittered♂)、散鳞镜鲤(Cyprinus carpiovar.mirror splittered♂)和兴国红鲤(Cyprinus carpiovar.Xingguo♀)的活动(每种鱼12条,饥饿和饱食各6条)。结果显示,3种鱼饥饿时的活动水平都显著低于饱食时,但3种鱼白昼或夜间的相对活动水平都不受摄食与否的显著影响;饥饿或饱食时,丰鲤