气相传输平衡技术制备LiGaO2薄膜

为获得与GaN薄膜晶格失配小的衬底材料，报道了利用气相传输平衡技术（VTE）在（100）β-Ga2O3单晶衬底上制备高度[001]取向LiGaO2薄膜的方法。经过X射线衍射分析表明得到的薄膜是由单相LiGaO2组成。利用扫描电镜（SEM）观察表面形貌，发现经气相传输平衡技术处理得到的薄膜表面形貌主要受温度的影响，表面晶粒尺寸随温度上升而增大。而X射线衍射测试表明随着温度上升，所得到的薄膜也从多晶向单晶化转变。在经过退火处理后，通过观察吸收谱发现LiGaO2薄膜中产生色心，并且色心的种类与温度有关。表明可以

Raman spectroscopic investigation of pure and ytterbium-doped rare earth silicate crystals

Raman spectroscopy was used to study the molecular structure of a series of selected rare earth (RE) silicate crystals including Y2SiO5 (YSO), LU2SiO5 (LSO), (Lu0.5Y0.5)(2)SiO5 (LYSO) and their ytterbium-doped samples. Raman spectra show resolved bands below 500 cm(-1) region assigned to the modes of SiO4 and oxygen vibrations. Multiple bands indicate the nonequivalence of the RE-O bonds and the lifting of the degeneracy of the RE ion vibration. Low intensity bands below 500 cm(-1) are an indication of impurities. The (SiO4)(4-) tetrahedra are characterized by bands near 200 cm(-1) which show a separation of the components of nu(4) and nu(2), in the 500-700 cm(-1) region which are attributed to the distorting bending vibration and in the 880-1000 cm(-1) region which are attributed to the symmetric and antisymmetric stretching vibrational modes. The majority of the bands in the 300-610 cm(-1) region of Re2SiO5 were found to arise from vibrations involving both Si and RE ions, indicating that there is considerable mixing of Si displacements with Si-O bending modes and RE-0 stretching modes. The Raman spectra of RE silicate crystals were analyzed in terms of the molecular structure of the crystals, which enabled separation of the bands attributed to distinct vibrational units. Copyright (C) 2007 John Wiley & Sons, Ltd.

The effect of an upstream turbine on a low-aspect ratio vane

The interaction between a high-pressure rotor and a downstream vane is dominated by vortex-blade interaction. Each rotor blade passing period two co-rotating vortex pairs, the tip-leakage and upper passage vortex and the lower passage and trailing shed vortex, impinge on, and are cut by, the vane leading edge. In addition to the streamwise vortex the tip-leakage flow also contains a large velocity deficit. This causes the interaction of the tip-leakage flow with a downstream vane to differ from typical vortex blade interaction. This paper investigates the effect these interaction mechanisms have on a downstream vane. The test geometry considered was a low aspect ratio second stage vane located within a S-shaped diffuser with large radius change mounted downstream of a shroudless high-pressure turbine stage. Experimental measurements were conducted at engine-representative Mach and Reynolds numbers, and data was acquired using a fast-response aerodynamic probe upstream and downstream of the vane. Time-resolved numerical simulations were undertaken with and without a rotor tip gap in order to investigate the relative magnitude of the interaction mechanisms. The presence of the upstream stage is shown to significantly change the structure of the secondary flow in the vane and to cause a small drop in its performance.

KARYOTYPE EVOLUTION OF SHREW MOLES (SORICOMORPHA: TALPIDAE)

The Chinese long-tailed mole (Scaptonyx fusicaudus) closely resembles American (Neurotrichus gibbsii) and Japanese (Dymecodon pilirostris and Urotrichus talpoides) shrew moles in size, appearance, and ecological habits, yet it has traditionally been classified either together with (viz subfamily Urotrichinae) or separately (tribe Scaptonychini) from the latter genera (tribe Urotrichini sensu lato). We explored the merit of these competing hypotheses by comparing the differentially stained karyotypes of S.fusicaudus and N. gibbsii with those previously reported for both Japanese taxa. With few exceptions, diploid chromosome number (2n = 34), fundamental autosomal number (FNa = 64), relative size, and G-banding pattern of S. fusicaudus were indistinguishable from those of D. pilirostris and U. talpoides. In fact, only chromosome 15 differed significantly between these species, being acrocentric in D. pilirostris, subtelocentric in U. talpoides, and metacentric in S. fusicaudus. This striking similarity is difficult to envisage except in light of a shared common ancestry, and is indicative of an exceptionally low rate of chromosomal evolution among these genera. Conversely, the karyotype of N. gibbsii deviates markedly in diploid chromosome and fundamental autosomal number (2n = 38 and FNa = 72, respectively), morphology, and G-banding pattern from those of Scaptonyx and the Japanese shrew moles. These differences cannot be explained by simple chromosomal rearrangements, and Suggest that rapid chromosomal reorganization Occurred ill the karyotype evolution of this species, possibly due to founder or bottleneck events.

亚东鲑的年龄与生长的研究

首次报道了亚东鲑在青藏高原河流中的生长特点。对1999—2002年间在亚东河共采集的462尾亚东鲑(体长范围为93—364mm)进行了年龄与生长的研究。通过鳞片对其中302尾进行年龄鉴定并建立Von Bertalanffy生长方程:雌性(♀)Lt=709.44[1-e-0.1656(t-0.0845)](R2=0.9993,n=132)和Wt=6017.46[1-e-0.1656(t-0.0845)]2.9724(R2=0.9845,n=132);雄性(♂)Lt=797.82[1-e-0.1428(t-0

交配期扬子鳄合唱吼叫的集群作用及其生物学意义

吼叫是扬子鳄(Alligatorsinensis)经常发生的行为之一,而目前有关吼叫行为生物学意义的资料还很缺乏。本文通过对安徽省扬子鳄繁殖研究中心繁殖区内扬子鳄吼叫行为的监测和观察发现,5-10月,扬子鳄常在水池边形成合唱吼叫(即两条以上鳄在同一时间段内一起吼叫);并且在交配期(6月份)吼叫声会引起四处分散栖息的个体向同一水体聚集,与非交配期相比具有明显的集群作用;交配期合唱吼叫具有6∶00-7∶00和11∶00-12∶00两个明显的高峰时间段,与其随后的交配高峰(夜间12∶00左右)都相差12h以上。

A solid-phase microextraction fiber coated with diglycidyloxycalix[4]arene yields very high extraction selectivity and sensitivity during the analysis of chlorobenzenes in soil

A novel fiber coated with novel sol-gel (5,11,17,23-tetra-tert-butyl-25,27-dihydroxy-26,28-diglycidyloxycalix[4]arene/hydroxy-terminated silicone oil; diglycidyloxy-C[4]/OH-TSO) was prepared for use with headspace solid-phase microextraction (HS-SPME) combined with gas chromatography (GC) and electron capture detection (ECD), which was applied in order to determine nine chlorobenzenes in soil matrices. Due to the improved fiber preparation, which increases the percentage of calixarene in the coating, the new calixarene fiber exhibits very high extraction selectivity and sensitivity to chlorine-substituted compounds. Various parameters affecting the extraction efficiency were optimized in order to maximize the sensitivity during the chlorobenzene analysis. Interferences from different soil matrices with different characteristics were investigated, and the amount extracted was strongly influenced by the matrix. Therefore, a standard addition protocol was performed on the real soil samples. The linear ranges of detection for the chlorobenzenes tested covered three orders of magnitude, and correlation coefficients > 0.9976 and relative standard deviations (RSD) < 8% were observed. The detection limits were found at sub-ng/g of soil levels, which were about an order of magnitude lower than those given by the commercial poly(dimethylsiloxane) (PDMS) coating for most of the compounds. The recoveries ranged from 64 to 109.6% for each analyte in the real kaleyard soil matrix when different concentration levels were determined over the linear range, which confirmed the reliability and feasibility of the HS-SPME/GC-ECD approach using the fiber coated with diglycidyloxy-C[4]/OH-TSO for the ultratrace analysis of chlorobenzenes in complex matrices.

Enhanced robotic body extension with modular units

The adaptation of robots to changing tasks has been explored in modular self-reconfigurable robot research, where the robot structure is altered by adapting the connectivity of its constituent modules. As these modules are generally complex and large, an upper bound is imposed on the resolution of the built structures. Inspired by growth of plants or animals, robotic body extension (RBE) based on hot melt adhesives allows a robot to additively fabricate and assemble tools, and integrate them into its own body. This enables the robot to achieve tasks which it could not achieve otherwise. The RBE tools are constructed from hot melt adhesives and therefore generally small and only passive. In this paper, we seek to show physical extension of a robotic system in the order of magnitude of the robot, with actuation of integrated body parts, while maintaining the ability of RBE to construct parts with high resolution. Therefore, we present an enhancement of RBE based on hot melt adhesives with modular units, combining the flexibility of RBE with the advantages of simple modular units. We explain the concept of this new approach and demonstrate with two simple unit types, one fully passive and the other containing a single motor, how the physical range of a robot arm can be extended and additional actuation can be added to the robot body. © 2012 IEEE.

一个基于自管理单元支持差分服务的Web容器

随着Internet的飞速发展,符合J2EE规范的Web容器已经成为部署企业Web应用的主流平台.同时,企业Web应用的多样化和复杂性的增长,迫切地要求Web容器提供差分服务的支持.然而,传统的Web容器采用尽力而为的服务模型,无法提供差分服务支持.已有的研究采用准入控制、优先级调度等方法来为Web容器提供差分服务支持,但是它们只能提供单调、静态的差分服务策略.提出了一个基于自管理单元的Web容器DSWC,它能够根据SLA定义提供两级差分服务支持.此外,提出了一个自适应差分服务策略选择算法,它能够根据动态变化的运行环境自适应地选择差分服务策略.原型系统的实验结果显示,DSWC能够有效地为请求提供符合SLA定义的细粒度的差分服务支持.

以活动为中心的个人信息管理

通过分析用户执行多任务的交互场景，基于活动理论，将任务、任务相关的信息以及任务间的关系统一纳入活动研究的框架，提出了以活动为中心的个人信息管理方式；从活动的静态结构、动态演变过程以及活动间的关系3个方面对活动进行建模；针对多活动场景中的用户交互和活动对象的内容提出了计算活动相关性的方法；并在此基础上。实现了以活动为中心的个人信息管理工具一一ACPIM(activity．centered personal information management)．评估结果显示：以活动为中心的个人信息管理有助于用户减轻认知和记忆负担，降低交互努力，从而提高工作效率．

三亚鹿回头石珊瑚物种多样性的空间分布

对三亚鹿回头珊瑚岸礁沿垂直岸线的5条断面上84个调查样方观测照相和室内判