域 WⅢ的Bergman核的计算

主要是计算域WⅢ 的Bergman核函数的显式表达式 .WⅢ ={W2 ∈C ,(W1 ,Z) ∈YⅢ(q) :｜W2 ｜2P <(1 -X) 3det(I Z Z) } .其中YⅢ ={ (W1 ,Z) ||W1 |2K相似文献   

Reinhardt域上和复Hilbert空间单位球上推广的Roper-Suffridge算子的性质

由α次的殆β型螺形映照的定义,分别给出推广的Roper-Suffridge算子在Reinhardt域上和复Hilbert空间中的单位球上保持α次的殆β型螺形性.     

有界完全Reinhardt域上的星形映照

将Roper-Suffridge算子在Reinhardt域上进行了推广,应用推广后的Roper-Suffridge延拓算子通过单位圆盘上全纯函数的α次凸性及近于凸性讨论多复变函数空间中相应的双全纯映照的星形性,从而得到Roper-Suffridge算子及其推广的新性质,并讨论算子的偏差.     

对称群的不可约表示

一般的有关表示论的书在讨论群的不可约表示时,为简便起见,基础域多半选取代数闭域,如复数域。在讨论对称群的不可约表示时,也有选取有理数域作为基础域的。本文将基础域取作域F,使得charF=0或charF+|s_n|,並且给出了域F上对称群的不可约表示全系的一个具体求法。     

离散赋值完满域的乘法群的构造(Ⅱ)

引言在1955～1956年间,作者曾经研究过离散赋值完满域的乘法群的构造,把 K.Hensel(1916)和 H.Hasse(1949)的关于-进数域情形的结果推进到一般的离散赋值完满域上(管纪文1956)。如所熟知,乘法群的构造问题,归结为单元群(Die Einseinheitengruppe)的构造问题。在-进数域情形,单元群得以整有理 p-进数为算子区,而构造问题也就是寻求单元群作为算子 Abel 群的基底,或者说,寻求单元在基底下的唯一表示式。在作者的前一工作中,则就一般的离散赋值完满域,将单元群的算子区扩充为极大绝对非分     

双二次多项式的Galois群一域对应

Galois 理论的基本定理,证明了有限维 Galoi 扩张 E/F 的全部中间域所成之集与Galois 群 GalE/F 的全部子群所成之集存在着一一对应(称为 Galois 群一域对应)。但是关于四次多项式的 Galois 群一域对应却不能叙说成一般的命题,只能作具体问题具体分析。本文将给出不可约的双二次多项式 f(x)=x~4+bx~2+c∈Q[x]的 Galois 群以及 Galois群一域对应的一些结果。     

关于域的几点注记

首先给出环R成为域的一个充分必要条件 ,然后给出域的加群自同态成为域自同态的充分必要条件。     

SL(2,Q_p)中的非初等离散子群的代数收敛性（英文）

在Kleinian群中,研究离散群的代数收敛性是一个重要的问题,群列的代数收敛性与流形的形变以及极限集的Hausdorff维数的收敛性有密切关系.随着非阿基米德域上的李群和非阿基米德域上的动力系统的发展,讨论非阿基米德域上的离散群的代数收敛性就是一个重要的问题.讨论了PSL(2,Q_p)中由r个元素生成的非初等离散群的代数收敛性,利用PSL(2,Q_p)中关于子群的非阿基米德Jorgensen不等式,以及群双曲Berkovich空间上的双曲等距性,证明了非初等群列代数收敛到非初等群列上.     

半线性群的子群结构

设 K为域, F为其素子域, V为 K上 n维线性空间,记 GLn(V)为 V上一般线性群。以 Ln(V)表示 V上全体可逆半线性变换全体组成的群。本文给出中间群 GLn(V) XΓ Ln(V)与中间域 F■ E■ K的对应关系。     

应用粒子群优化-条件随机域的文本生物实体识别

针对生物医学文本中传统生物实体识别算法的精确度不高的问题,提出了一种新的基于粒子群优化-条件随机域的生物实体识别算法.新算法利用改进的粒子群优化算法训练条件随机域模型,并将训练后的条件随机域模型应用到生物实体的识别上.改进的粒子群优化算法引入粒子群聚集度来防止粒子群过早地陷入局部收敛,用迭代间对数似然相对变化率来控制算法的收敛,用线性变化的惯性因子和学习因子来控制搜索范围.实验结果表明,基于改进粒子群优化的条件随机域模型较隐马尔科夫模型、最大熵马尔科夫模型、支持向量机以及传统条件随机域模型等方法具有更高的精确率和召回率.     

一类穿孔域所生成的离散群的表示定理

在构造了一类穿孔域到单位圆盘的共形映照的基础上，经过精细的讨论，得到了这类穿孔域所生成的离散群的表示定理。     

A mobile accessible closed multi-part group communication scheme in IPv6 network

To solve the problems of current IP multicast which includes poor inter-domain many-to-many group support, security vulnerabilities and dependency to specific multicast infrastructure, a mobile accessible closed multi-part group （MACMPG） communication protocol in IPv6 network is proposed. By extending the single source multicast protocol, the communication channel for multi-part group communication across domains is established. Based on lPv6 CGA, the secure closed group communication scheme is designed. The access to the multicast traffic only confined to the authorized senders and receivers and only trusted routers are allowed to be the branch points of MACMPG tree. By tunneling mechanism, the MACMPG traffic can be transmitted across non-MACMPG routing area, and the mobile nodes can join the group remotely and roam freely between domains, which eliminates the dependency on specific IP multicast routing.     

The importance of sequence diversity in the aggregation and evolution of proteins

Incorrect folding of proteins, leading to aggregation and amyloid formation, is associated with a group of highly debilitating medical conditions including Alzheimer's disease and late-onset diabetes. The issue of how unwanted protein association is normally avoided in a living system is particularly significant in the context of the evolution of multidomain proteins, which account for over 70% of all eukaryotic proteins, where the effective local protein concentration in the vicinity of each domain is very high. Here we describe the aggregation kinetics of multidomain protein constructs of immunoglobulin domains and the ability of different homologous domains to aggregate together. We show that aggregation of these proteins is a specific process and that the efficiency of coaggregation between different domains decreases markedly with decreasing sequence identity. Thus, whereas immunoglobulin domains with more than about 70% identity are highly prone to coaggregation, those with less than 30-40% sequence identity do not detectably interact. A bioinformatics analysis of consecutive homologous domains in large multidomain proteins shows that such domains almost exclusively have sequence identities of less than 40%, in other words below the level at which coaggregation is likely to be efficient. We propose that such low sequence identities could have a crucial and general role in safeguarding proteins against misfolding and aggregation.     

'Pseudo' domains in phage-encoded DNA methyltransferases

5-Cytosine-DNA-methyltransferases, which are found in many organisms ranging from bacteriophages to mammals, transfer a methyl group from S-adenosylmethionine to the carbon-5 of a cytosine residue in specific DNA target sequences. Some phage-encoded methyltransferases methylate more than one sequence: these enzymes contain several independent target-recognizing domains each responsible for recognizing a different site. The amino-acid sequences of these multispecific methyltransferases reveal that some enzymes in addition carry domains that do not contribute to the enzymes' methylation potential, but strongly resemble previously identified target-recognizing domains. Here we show that introducing defined amino-acid alterations into these inactive domains endows these enzymes with additional methylation specificities. Gel retardation analysis demonstrates that these novel methylation specificities correlate with the acquisition of additional DNA-binding potential of the proteins.     

用组策略在机房中实现对软件的筛选分发

在基于域的网络管理模式下，采用组策略技术对机房客户端进行统一、集中的软件分发管理，使软件安装工作比传统方式变得更加高效和快捷．根据软件的不同使用性质，讨论具体的分发方式和实现形式．利用组策略控制台对组策略对象进行安全筛选以及利用WQL编写WMI筛选器，动态判断组策略对象的作用域．     

HIPS-g-GMA共聚物对PBT/HIPS体系性能的影响

研究了高抗冲聚苯乙烯与甲基丙烯酸缩水甘油酯接枝共聚物(H IPS-g-GMA)作为增容剂,对聚对苯二甲酸丁二醇酯/高抗冲聚苯乙烯(PBT/H IPS)体系性能的影响。用DSC、SEM、DMA及力学性能等方法研究PBT/H IPS/H IPS-g-GMA三元共混体系的结晶、形态结构、动态力学性能及力学性能随组成的变化。SEM结果显示:含有增容剂的共混体系的微区尺寸明显变小,几乎看不到光滑的球形粒子,界面比较模糊,分不清两相结构;且随着增容剂量的增加,体系的微区尺寸明显变小;以PBT为分散相,在增容体系中的PBT出现了分级结晶现象,结晶温度降低。DMA结果表明:在PBT/H IPS-g-GMA体系中有接枝共聚物生成,体系中两个聚合物的Tg松弛均出现了较明显的降低,体系的相容性得到改善;增容后体系的力学性能提高。     

Heisernberg群上低阶特征值的估计

研究Heisernberg群Hn上的Kohn Laplacian算子的特征值问题,通过构造合适的测试函数,给出低阶特征值估计的一个一致不等式.     

Structures of complement component C3 provide insights into the function and evolution of immunity

The mammalian complement system is a phylogenetically ancient cascade system that has a major role in innate and adaptive immunity. Activation of component C3 (1,641 residues) is central to the three complement pathways and results in inflammation and elimination of self and non-self targets. Here we present crystal structures of native C3 and its final major proteolytic fragment C3c. The structures reveal thirteen domains, nine of which were unpredicted, and suggest that the proteins of the alpha2-macroglobulin family evolved from a core of eight homologous domains. A double mechanism prevents hydrolysis of the thioester group, essential for covalent attachment of activated C3 to target surfaces. Marked conformational changes in the alpha-chain, including movement of a critical interaction site through a ring formed by the domains of the beta-chain, indicate an unprecedented, conformation-dependent mechanism of activation, regulation and biological function of C3.     

Scheme on Cross-Domain Identity Authentication Based on Group Signature for Cloud Computing

In the cloud computing, different cloud service providers are often in different trust domains. As the traditional identity authentication mode cannot be applied to the cloud computing, the cross-domain identity authentication mechanism is needed to solve the identity authentication problem in the cloud computing. In view of the security problems in cloud computing, a cross-domain identity authentication scheme based on group signature is proposed. This scheme introduces a group of cloud service providers and users who are located in different trust domains. Any member of the group can generate the signature on behalf of the whole group, making the user access the cloud service provider in the case of privacy security. At the same time, with traceability it can track illegal operation of illegal users. In addition, the scheme uses the Chinese Remainder Theorem to integrate the message, and it can control the length of the data in the calculation process, simplifying the calculation process. It also realizes the join and revocation of group members without changing the key of other legitimate group members, and the maintenance cost of authentication schemes is low. The results show that the scheme has the advantages of anonymity, anti-counterfeit, traceability, anti-joint attack and so on. It can not only realize tracking function under the condition of guaranteeing user's privacy, but can also simplify the authentication calculation process to improve the efficiency of the cross domain identity authentication, and its performance is more suitable for large-scale cloud computing environment.     

Engineering galactose-binding activity into a C-type mannose-binding protein.

Calcium-dependent or C-type carbohydrate-recognition domains are homologous protein modules found in a variety of animal lectins. Selective binding of sugars by these domains is essential for glycoprotein clearance, cell-cell adhesion and pathogen neutralization. Although various C-type carbohydrate-recognition domains share sequence identity ranging from 20 to 55%, their sugar-binding characteristics vary widely. The structure of a mannose-binding carbohydrate-recognition domain in complex with a saccharide ligand suggests that two glutamic acid-asparagine pairs are essential determinants of ligand binding by this domain. In C-type lectins that bind galactose with higher affinity than mannose, one of these pairs is replaced by glutamine-aspartic acid. Here we shift the sequence of the mannose-binding protein to correspond to that found in galactose-binding domains in order to test the importance of these residues in sugar-binding selectivity. This simple switch in the position of a single amide group alters the binding activity of the domain so that galactose becomes the preferred ligand.