共查询到20条相似文献，搜索用时 187 毫秒
1.
DNA is the hereditary material in humans and almost all other organisms. It is essential for maintaining accurate transmission of genetic information. In the life cycle, DNA replication, cell division, or genome damage, including that caused by endogenous and exogenous agents, may cause DNA aberrations. Of all forms of DNA damage, DNA double-strand breaks(DSBs) are the most serious. If the repair function is defective, DNA damage may cause gene mutation, genome instability, and cell chromosome loss, which in turn can even lead to tumorigenesis. DNA damage can be repaired through multiple mechanisms. Homologous recombination(HR) and non-homologous end joining(NHEJ) are the two main repair mechanisms for DNA DSBs. Increasing amounts of evidence reveal that protein modifications play an essential role in DNA damage repair.Protein deubiquitination is a vital post-translational modification which removes ubiquitin molecules or polyubiquitinated chains from substrates in order to reverse the ubiquitination reaction. This review discusses the role of deubiquitinating enzymes(DUBs) in repairing DNA DSBs. Exploring the molecular mechanisms of DUB regulation in DSB repair will provide new insights to combat human diseases and develop novel therapeutic approaches. 相似文献
2.
LU Jin-yu LUO Yao-zhi LI Na 《浙江大学学报(A卷英文版)》2007,8(7):1091-1100
Under certain load pattern, the geometrically indeterminate pin-jointed mechanisms will present certain shapes to keep static equalization. This paper proposes a matrix-based method to determine the mobility and equilibrium stability of mechanisms according to the effects of the external loads. The first and second variations of the potential energy function of mechanisms under conservative force field are analyzed. Based on the singular value decomposition (SVD) method, a new crite- rion for the mobility and equilibrium stability of mechanisms can be concluded by analyzing the equilibrium matrix. The mobility and stability of mechanisms can be classified by unified matrix formulae. A number of examples are given to demonstrate the proposed criterion. In the end, criteria are summarized in a table. 相似文献
3.
1 Introduction The giant magneto-i mpedance ( GMI) effect is alarge change of AC i mpedance of soft magnetic con-ductor upon application of an external magnetic field .It has drawn much research attention because of itsprospective applications in high sensitive magnetic sen-sors. GMI materials can be of the forms of homoge-neous wires[1-3], ribbons[2 ,4 ,5], fil ms[3], inhomoge-neous forms of microtubes[6 ,7]and sandwich structuredfil ms[8-10]. Thin fil ms are more preferable for sensorappl… 相似文献
4.
Study on power systemchaotic phenomena is oneimportant aspect in power system stability stu-dies[1—3]. Early studies, such as Lee[4], Chiang[5],Wang[6]and Tan[7], mainly focused on interpretingthe behavior of chaotic oscillations. Later researches,such as Wu[8], Rajesh[9], Jia[10,11], Srivastava[12]and Abed[13]began to concern the following topics,such as interaction of chaotic motion and system dy-namics, the relationship of power system stability re-gion and chaos, and the methods to eli… 相似文献
5.
CHEN Li-qun CHENG Chang-jun ZHANG Neng-hui Department of Mechanics Shanghai Institute of Applied Mathematics Mechanics Shanghai University Shanghai China 《上海大学学报(英文版)》2000,(Z1)
l introductionThe Galerkin trUncation is widely used to stody thedynandcal behavior (especially the nonlinear dynamicalbehavior) of,trU.tUre,[i]. The Galerkin method is alsoaPPlied to stUdy dynamical behavior of viscoelashcbeams. Suire and Cederbaum [2] analyzed periodic andchaohc behavior of viscoelastic beams with the Idledeflection, and the constitUtive relation in their work isthe BoltZmann superposition Principle. Argyris[']myes-tigated chaohc motion of viscoelastic beamsbased on a … 相似文献
6.
Let G be a weighted graph with adjacency matrix A=[aij]. An Euclidean graph associated with a molecule is defined by a weighted graph with adjacency matrix D=[d/ij], where for i≠j, dij is the Euclidean distance between the nuclei i and j. In this matrix dij can be taken as zero if all the nuclei are equivalent. Otherwise, one may introduce different weights for different nuclei.Balasubramanian (1995) computed the Euclidean graphs and their automorphism groups for benzene, eclipsed and staggered forms of ethane and eclipsed and staggered forms of ferroeene. This paper describes a simple method, by means of which it is possible to calculate the automorphism group of weighted graphs. We apply this method to compute the symmetry of tetraammine platinum(Ⅱ) with C2v and C4v point groups. 相似文献
7.
田凤俊 《宁夏师范学院学报》2006,27(5):74-80
Ⅰ.BackgroundChina has enjoyed hundreds of years of sustained[1]educational provision for its citizens(Surowski,2002)i.E-ducation has always been a priority in China and this hasled to a society,which enjoys the privileges of educationaldevelopment,expect… 相似文献
8.
9.
《湘南学院学报》1995,(2)
<正> In this paper, we consider the oscillation of first order differential equation with several delays of the formWhere Pi,ri,(i= 1,2,...,n) are positive constants. Our aim is to give a necessary and sufficient condition for all sollution of (0. 1) to be oscillation. Which answers an open problem by B.G Zhang in [1]. 相似文献
10.
蒋岳祥 《浙江大学学报(A卷英文版)》2004,5(3):335-342
Suppose {Xi,i≥1} and {Yi, i≥1} are two independent sequences with distribution functions and , respectively. Zi,n is the combination of Xi and Yi with a probability for each I with 1≤ i≤n. The extreme value distribution GZ(x) of this particular triangular array of the i.i.d. Random variables Z1,n,… Z2,n, Zn,n is discussed. We found a new form of the extreme value distributions i)ΦAα1(x)Φα2 and ii) ψAα(x)ψα2(x)α1<α2), which are not max-stable. It occurs if FX and FY belong to the same MDA(Φ) or MDA(Ψ). 相似文献
11.
X-Code is one of the most important redundant array of independent disk (RAID)-6 codes which are capable of tolerating double disk failures. However, the code length of X-Code is restricted to be a prime number, and such code length restriction of X-Code limits its usage in the real storage systems. Moreover, as a vertical RAID-6 code, X-Code can not be extended easily to an arbitrary code length like horizontal RAID-6 codes. In this paper, a novel and efficient code shortening algorithm for X-Code is propo... 相似文献
12.
包佃清 《连云港师范高等专科学校学报》2004,(4):84-86
DLL技术是当今计算机软件领域中广泛采用的一种技术，在现代软件设计过程中占有重要的地位。Windows系统中大量的运用了DLL技术。文章介绍了DLL的基本原理及实现方法，讨论基于DLL技术的代码复用及内存共享技术，阐述DLL中的内存共享机制及代码复用的实现原理，给出了用Delphi编写的Dll示例程序的源代码、实现过程和效率分析。 相似文献
13.
从二值图像的区域特征出发，提出了基于四叉树的二值图像四边形区域压缩算法，该算法的思想是将二值图像用四叉树进行四分区域划分，在同一个区域中如果像素值相同则可用一个元素表示，否则继续划分，该算法的优点体现在如下两个方面：1．采用二进制移位的思想提高了MD码的生成效率。2．采用基于对数模型的方法进行区域像素压缩。该算法的内存开销小，运行速度高于其它相关方法。 相似文献
14.
Design patterns are micro architectures that have proved to be reliable,robust and easy to implement.Detecting design pattern from source code of object-oriented system can help a designer,a developer or a maintainer to understand the software system.In this paper,a new method is provided which can detect design patterns from source code combining both static and dynamic analysis.To acquire the run-time dynamic information of software systems,a code instrumentation method is adopted.At the same time,all static and dynamic information is presented in UML diagrams format.The pattern detection process and its detection results are visual and interactive.This method is tested on a call center and a traffic simulation system.Experimental results prove that the method is effective in design patterns detection. 相似文献
15.
W-CDMA系统中的Turbo Code仿真 总被引：1，自引：0，他引：1
在第三代移动通信系统W CDMA和CDMA2 0 0 0中 ,turbocode在高速数据传输业务方面已倍受青睐 .本文给出了turbocode在瑞利衰落信道和加性高斯白噪信道下的性能仿真结果 ,并在各种不同条件下与卷积码的性能进行了比较 .得到了较为可信的仿真结果 . 相似文献
16.
GPS接收机实现的关键技术包括伪随机码(PN)如C/A码、P码的生成和捕获、定位算法的实现等。C/A码短、易于直接捕获、用于粗测距,P码特长、难于直接捕获、用于精测距。P码直接捕获分为时域法和频域法,频域法比时域法效率高。P码频域的直接捕获法分为扩展复制重叠法XFAST、均值法和直接法。本文深入地研究了这些捕获法特点,提出了采用小波法提高P码频域的捕获效率,并对结果进行了分析。 相似文献
17.
研究了多用户场景下多载波码分多址系统（MC—CDMA）的下行信道和功率分配,并将吞吐最大化问题建模成一个混合整数优化问题．为了简化分析,将问题分成2个低复杂度的子问题：功率分配和信道分配．这2个子问题可分别被一个次最优自适应功率分配算法（APA）和一个最优自适应信道分配算法（ACA）解决．通过联合APA和ACA算法,进一步提出了一个自适应信道和功率的分配方案．仿真结果表明：与传统的均匀功率分配算法相比,提出的APA算法更加适用于MC—CDMA系统;此外,提出的自适应信道和功率分配方案可以显著地提高系统吞吐量性能． 相似文献
18.
Reversible variable length codes (RVLCs) have received much attention due to their excellent error resilient capabilities. In this paper, a novel construction algorithm for symmetrical RVLC is proposed which is independent of the Huffman code. The proposed algorithm's codeword assignment is only based on symbol occurrence probability. It has many advantages over symmetrical construction algorithms available for easy realization and better code performance. In addition, the proposed algorithm simplifies the codeword selection mechanism dramatically. 相似文献
19.
G代码的解释或编译是数控系统软件中的一个不可缺少的环节。对此,提出了一个新的算法,阐述了该算法的原理和实现方法。该算法将G代码编译成协议整型数据包PIDP,利用PIDP,使控制软件的实现更加方便。其算法软件是一种用于上下位机结构开放式数控系统的新型G代码编译器中的关键模块,它编译出的目标码为上下位机奠定了一个软件接口基础。 相似文献
20.
为了能够实时采集图像并识别二维码所包含的信息, 通过LabVIEW构建程序框图, 运用图像灰度化、图像二值化、图像定位等研究方法, 设计了一套运行速度快、代码简洁、成功率高的二维码识别系统.测试结果表明, 识别成功率较高, 运行速度约35 ms/图, 可以满足生活或工业要求. 相似文献