The sequence of 55 kb on the left arm of yeast chromosome XVI identifies a small nuclear RNA,a new putative protein kinase and two new putative regulators

We have sequenced and analysed a 55 786 bp fragment located on the left arm of chromosome XVI of Saccharomyces cerevisiae. The sequence contains 29 non-overlapping open reading frames (ORFs) longer than 300 bp, among which 12 genes have previously been sequenced: OYE3, REV3, SVS1, BEM4, CDC60, KIP2, PEP4, SPK1, PAL1, KES1, SNR17B and RPL37A. Three new ORFs, P2591, P2594 and P2597 are highly homologous to the human phosphotyrosyl phosphatase activator PTPA, to the pleiotropic regulator PRL1 of PP1 and PP2a protein phosphatases in plants and to the protein kinase PAR-1 in Caenorhabditis elegans, respectively. Three other ORFs, P2545, P2567 and P2578 have significant homology with ORFs of unknown function located on yeast chromosomes VIII, XVI and IV respectively. The sequences in nucleotides and in amino acids have been deposited in the EMBL data library under the Accession Number X96770.     

节理岩体表征单元体尺寸确定的数值模拟

从节理岩体表征单元体的力学意义出发,在通过对某物理试验结果进行模拟以验证RFPA程序模拟节理岩体强度及破裂模式具有适用性的基础上,提出一种基于RFPA数值模拟确定节理岩体表征单元体的方法。该方法基于蒙特卡洛法生成二维节理裂隙网格,实现节理裂隙的表征,将其导入岩石破裂过程分析软件中,分析节理岩体弹性模量和单轴抗压、抗拉强度的尺寸效应和各向异性,并据此确定了节理岩体的表征单元体尺寸。最后,针对某采场围岩节理面统计参数,分析讨论节理岩体的尺寸效应和各向异性,通过综合分析确定了节理岩体的弹性模量、抗压强度和抗拉强度等参数,并得出其表征单元体的尺度为6 m×6 m,这为后续的岩石力学研究奠定基础。     

基于结构表征单元体的岩体力学参数选取

针对基于数值试验岩体力学参数的选取开展研究。通过现场节理裂隙调查、统计分析得到岩体节理面分布模型;采用三维随机节理模拟技术构建基于统计分析的岩体表征单元体数值模型,并就此开展单轴压缩数值试验确定结构表征单元体;对表征单元体进行三轴压缩数值试验,确定岩体的抗剪强度参数。研究结果表明：研究角砾岩的表征单元体尺寸为2m×2m×2m,得到的岩体力学参数与基于Heok-Brown强度指标较为一致;块体采用摩尔-库伦本构模型、节理面采用库伦滑移本构模型能够较好地反映研究角砾岩体的力学特性;基于结构表征单元体的岩体力学参数选取方法是合理的。     

基于节理网络模型的岩体REV数值估算与无网格伽辽金法（EFGM）

论文分为两大部分。第一部分提出了一种数值方法,用来估算节理岩体的REV值。其过程为：首先取不同尺寸的岩体,岩体中的节理位置由Monte－Carlo法确定;然后将这些岩体剖分成有限元网格,对其作数值试验,获取岩体的力学参数;最后分析岩体力学参数与尺寸的关系,从而确定REV值。该法充分考虑了节理网络生成的随机性。第二部分研究无网格伽辽金法（EFGM）。论文在介绍EFGM基本原理的基础上,研究该法用于岩体工程的可行性,比如用该法模拟边坡开挖过程、模拟不连续面、求解接触摩擦问题;并进一步对EPGM作了两点改进,即EFGM对集中力荷载的处理以及EFGM的一种点积分实现形式。     

格子-Boltzmann方法模拟多孔介质内自然对流蓄热过程

以在高温热量存储、太阳能利用和建筑节能中有着广泛应用的多孔蓄热装置为研究对象,基于格子-Boltzmann方法(LBM)的基本原理,建立表征体元尺度(REV)上多孔介质自然对流的热流耦合方程,对多孔介质区域内的定温加热过程进行数值计算,探索了蓄热装置工作效果与多孔介质材料和内部流体特性的关系。分析获得了多孔介质渗透率和工质热膨胀率增大对多孔介质蓄热的强化作用,以及强自然对流作用下温度场分布所出现的不均匀特性。     

REV Grid Technique for Reservoir Upscaling

Abstract

Lasseter et al. (Lasseter, T. J., Waggoner, J. R., Lake, L. W. (1986 Lasseter, T. J., Waggoner, J. R. and Lake, L. W. 1986. Reservoir Heterogeneities and Their Influence on Ultimate Recovery. Reservoir Characterization 545Orlando, FL: Academic Press Inc..  [Google Scholar]). Reservoir Heterogeneities and Their Influence on Ultimate Recovery. Reservior Characterization, Orlando, Florida: Academic Press Inc., 545.) proposed that scale-up of properties should be done from the scale of a representative elementary volume (REV), a volume for which the measured property does not change with an increase in scale over a given limit of scale. The notion of REV has been a quite argued concept owing to its definition is not unequivocal, and it did not address how to obtain it in real system, some people even argue if REV really exists. Qi et al. (Qi, D., Wong, P. M., Liu, K. (2001 Qi, D., Wong, P. M. and Liu, K. 2001. An improved global upscaling approach for reservoir simulation. Petroleum Science and Technology, 19(7–8): 779–795. [CROSSREF][Taylor & Francis Online], [Web of Science ®] , [Google Scholar]). An improved global upscaling approach for reservoir simulation. Petroleum Science and Technology 19(7–8):779–795.) based on REV concept, proposed the new idea of REVG (representative elemental volume grid). This article further developed this idea, and based on it, proposed the REV grid upscaling technique. This new technique uses an algorithm, which is a combination of two-procedure-upgridding with reverse stepwise approach, it is a field-oriented 3D model. The new method concentrates on constructing a unique coarse grid, referred to as pseudo-REVG, which could best describe the heterogeneity of the original model at given scale. Mathematically, the variance of properties in REVG is the smallest within each block, and largest between the blocks. The proposed method is applied to two case studies, one of them is a 3D multiphase real reservoir, and the flow simulation results show that the consistency of the reservoir behavior before and after upscaling with REV grid technique is excellent. It is much better than that of the conventional upscaling methods.     

一种用于中继卫星SMA系统在轨标校的新方法

天基测控是国际测控领域未来发展的重要方向,而跟踪与数据中继卫星系统是天基测控的典型代表。近年来,随着中低轨卫星用户数目的显著增加,中国新一代的中继卫星系统将提供SMA服务,用于完成多个用户星的测控数传任务。为了实现良好的波束形成,必须对SMA相控阵天线进行在轨标校。目前已有的星载相控阵天线标校方法中,REV法不需要增加额外设备、实用性较强,获得了更广泛的研究,但其只适合在时间与硬件资源较宽松的条件下应用。为了提高SMA系统的使用效率,节省标校时间,提出了一种新的基于正交四相旋转的标校方法,该方法通过对接收信号的功率方程进行降维反演,能在保精度的前提下快速完成中继卫星SMA系统的在轨动态标校,标校时间远小于REV法,因此更有利于在工程实践中应用。     

基于数值实验的节理岩体变形特性尺寸效应

借用有限元数值实验技术,通过节理随机概率模型生成0.4、0.6、0.8、1.0 m和1.1 m等5组不同尺寸的节理岩体试件,每个尺寸组10个试件.在5 MPa围压下,对试件轴向分级加载,获得同一尺寸下每个试件的应力-应变曲线,分析每组10条应力应变曲线及数据随试件尺寸的变化规律.分析结果发现:尺寸较小时,同组变形曲线比较分散,数据离散程度相对较大;随着尺寸的增大,曲线束积聚程度提高,数据离散性减小,这说明试件受力变形特性存在尺寸效应,可以获得该方法获取岩体变形特性的特征尺寸.     

摄像机的新技术运用

科技日新月异,物理学与材料学的飞速发展为生产应用提供了坚实的基础,在摄像机的存储介质方面,也发生了翻天覆地的变化：由单一的磁带存储发展到今天的包括专业蓝光（Blu-ray Disc,缩写为BD）、P2卡、REV硬盘等,或许在不久的将来会有更新、更稳定、更高质量的存储介质出现,使广播电视系统的使用者更便捷更出色地完成工作。对近年来出现的技术含量较高的蓝光盘、P2卡、REV硬盘3种新介质作初步的、技术性的探讨,与同行交流。     

网络环境下所采用的软件技术研究

考虑到网络环境下的异构性以及传输带宽的限制 ,出现了许多不同的软件技术 ,对从传统的客户 -服务器模式到目前比较新的移动Agent技术进行了分析 ,并指出了其各自在技术与实现上的优点和缺点及适用范围