26 resultados para ALV-1428

em Chinese Academy of Sciences Institutional Repositories Grid Portal


Relevância:

10.00% 10.00%

Publicador:

Resumo:

分析并观察了沿驱动段轴向分布多火塞燃烧驱动段的性能。提出主膜处同一管截面均匀分布上三火花塞引燃的点火方法。用这种点火方法驱动产生的入射激波强度重复性较高,激波后气流速度、温度和压力的定常亦大大改善,可满足气动试验实际要求。提出在驱动段尾端串接卸爆段来消除爆轰波反射高压,从而可使反向爆轰驱动段用来产生高焓高密度试验气流。这种反向爆轰驱动产生的入射激波重复性高,激波衰减弱。在主膜处的收缩段产生的反射波可缓解爆轰波后跟随的稀疏波的不利影响,从面使前向爆轰驱动具有实用性。在产生的入射波激强度相同条件下,前向爆轰驱动所需的爆轰驱动段可爆混合气初始压力可较反向爆轰低近一个量级。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

利用坐标旋转方法和Kogelnik耦合波理论,建立了光轴方向任意时单轴晶体中体光栅布拉格衍射的耦合波方程,分析了LiNbO3晶体的光轴方向对光折变体全息光栅的各向同性和各向异性布拉格衍射性质的影响。模拟计算表明,在给定光栅的结构参量时,通过适当选择光轴方向角可以使得光折变体光栅的各向同性和各向异性布拉格衍射的衍射效率达到最大,给出了相应类型的衍射效率取得最大值时晶体光轴的大致方向。这些理论分析为光折变体全息光学器件的优化设计和进一步广泛应用提供了很好的理论参考依据。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

探求新的具有优良的热学和光学性能的基质玻璃系统,是获得具有宽带宽和增益平坦的掺Er^3+光纤放大器(EDFA)的一种有效途径。制备了一种新型氧氟碲酸盐玻璃TeO2-BaF2-LaF3,并对其热学性能和光学性质进行了测试。应用乍得-奥菲尔特(Judd-Ofelt)理论计算了Er^3+离子的J-O理论参量和荧光寿命r。探讨了氟化物的引入对碲酸盐玻璃结构的改变的影响,并分析了其对玻璃的热学性质和光学性质的影响。实验发现,获得的氧氟碲酸盐玻璃具有优良的热学稳定性(△T=156.6C),宽的荧光半峰全宽(72nm)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

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

Relevância:

10.00% 10.00%

Publicador:

Resumo:

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.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

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.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

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

Relevância:

10.00% 10.00%

Publicador:

Resumo:

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。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

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.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

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.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

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.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

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

Relevância:

10.00% 10.00%

Publicador:

Relevância:

10.00% 10.00%

Publicador: