Numerical analysis of device performance of metamorphic InyAl1-yAs/InxGa1-xAs(0.3⩽x⩽0.6) HEMTs on GaAs substrate

A numerical model describing the influence of InAs mole fraction on metamorphic HEMT structures (MM-HEMT) is proposed. The material properties are calculated using the Monte Carlo method, while the charge control law is calculated using a self-consistent solution of Poisson's and Schrodinger's equations. The modeling of the dc, ac, noise and high frequency performance of a device with 0.25-μm gate length is performed using the quasi-two-dimensional (Q2D) approach. This analysis shows that an InAs mole fraction of about 0.40 is an optimum composition for manufacturing high gain, low noise amplifiers. In this range of composition, the performance of MM-HEMT structures is similar to that obtained for lattice-matched HEMTs on InP substrates     

Active properties of carbon nanotube field-effect transistors deduced from S parameters measurements

AC performances of carbon nanotube field-effect transistors (CNT-FETs) are analyzed by means of scattering parameters measurements. The active ac properties of CNT-FETs are clearly demonstrated up to 80 MHz and indications of active behavior are obtained up to 1 GHz. From these measurements, a small signal equivalent circuit is proposed and validated up to 10 MHz. The extraction procedure and the determination of the intrinsic ac elements of CNT-FETs are pointed out.     

中国含油气区陆相沉积几个理论问题

在总结中国陆相含油气盆地沉积特征的基础上，提出了中国陆相沉积盆地的沉积模式及演化模式，由内陆湖盆湖底复杂的地形以及水下隆起带往往造成湖水的环境，由湖盆周边山区的不均衡活动，造成湖盆沉积中心的迁移，对生储盖层的分布有一定的影响，我国某些大型陆相沉积盆地具有湖海的性质，即既有湖泊沉积特征，又具有某些海洋沉积的特征。     

Use of multiple urolume endourethral prostheses in complex bulbar urethral strictures

PURPOSE: We evaluated patients who received multiple UroLume Wallstents during the North American UroLume trial for the treatment of recurrent bulbar urethral strictures. MATERIALS AND METHODS: A total of 41 patients received multiple UroLume stents. The clinical histories and therapeutic outcomes of these patients were reviewed. RESULTS: Of the patients 23% required placement of multiple urethral stents. Stents placed at the initial procedure were required for strictures longer than 2.5 cm. and for multiple, separate strictures. Indications for secondary insertion included recurrent stricture adjacent to the stent, hyperplastic tissue growth within the stent and gaps between previously adjacent stents. The repeat treatment rate was 43.9% versus 14.3% for the study group overall. Urine flow rates and symptom scores in the multiple stent group showed improvement similar to that of the study group overall. CONCLUSIONS: Patients who required multiple stents had greater rates of repeat treatment but similarly improved urine flows and symptom scores, which were maintained at 2 years.     

Homogeneous precipitation of Dy2O3 nanoparticles-effects of synthesis parameters

The experimental parameters that control the size and size distribution of dysprosium oxide nanoparticles synthesized by homogeneous precipitation technique have been systematically investigated. The particles were characterized with respect to their size, shape, and thermal decomposition behavior. It was found that the precipitated particles were spherical, uniform in size, and amorphous, which upon heating in air, decomposed into the oxide form with no change in morphology. The size and size distribution of the particles showed strong dependence on the metal cation concentration ([Dy3+]) and weak dependence on urea concentration and aging time. In addition, the presence of chlorine ions (Cl-) was found to have significant effect on the growth and agglomeration of the particles. Aggregation mechanism as the growth mechanism is offered to explain the effects of these synthesis parameters on the morphology, size, and size distribution of dysprosium oxide particles.     

Cytotoxic and antioxidant constituents from Garcinia subelliptica

Two new triterpenoids, garcinielliptones Q (1) and S (3), and a new phloroglucinol, garcinielliptone R (2), were isolated from the seed of Garcinia subelliptica. Their structures were established by analysis of their spectroscopic data. Phloroglucinol, garcinielliptone FC (4) from this plant exhibited a significant increase of antiproliferative effect, while 4 combined with cisplatin significantly caused decrease of cell inhibition induced by cisplatin in NTUB1. Exposure of NTUB1 cells to 4 cotreated with cisplatin for significantly decreased the amount of reactive oxygen species (ROS) than that of the total amount generated by 4 and cisplatin. These results suggested that 4 could protect the cisplatin toxicity through reduction of ROS in NTUB1. Phloroglucinols, garcinielliptones, A (5) and F (7), and garsubelline A (6), from this plant, revealed ABTS radical cation scavenging activity and 5 displayed an inhibitory effect on xanthine oxidase. These finding showed that 5-7 may be used as antioxidants.     

华北克拉通分割与鄂尔多斯上古生界含气问题

华北克拉通经历了印支、燕山和喜马拉雅期构造运动,主要在从西向东的构造挤压力和东部的构造拉张力的联合作用下,把克拉通分割成阿拉善、鄂尔多斯、山西、河淮、胶辽和北部的内蒙古几个地块。在鄂尔多斯的上古生界煤成气资源十分丰富,根据烃源、运移和储集层、圈闭条件分析,在这里应该有6个含气带,即乌达－银川、杭锦旗、东胜－靖边、神木－绥德、米脂－延安和天环坳陷。     

Deletional mapping of fifteen mouse VH gene families reveals a common organization for three Igh haplotypes

In addition to the content of germ-line variable gene segments, the organization of V genes has been implicated in the development of the Ab repertoire. We have searched the expressed VH genes of BALB/c mice for additional VH gene families and utilized deletion mapping to explore the extent of VH gene family interspersion. We have identified and characterized one new VH gene family (VH15) and extended our previous studies of the Igha and Ighb haplotypes to include a third haplotype (Ighj) using a newly developed panel of pre-B cell lines (CXCB cell lines). We conclude that the Igha, Ighb, and Ighj haplotypes have a similar Igh-V locus structure. A refined deletional map for 15 VH gene families and an individual member of the VHSM7 family (H10) has been constructed based on the deletion profiles of 72 rearranged heavy chain loci. These results demonstrate previously unrecognized examples of interspersion among members of the VHS107, VH10, and VHSM7 families.