水下高速航行器壳体联结强度分析

随着超空化技术被用于水下航行器减阻提速,水下高速航行器的结构设计也成为热点。为了确保在设计范围内航行器可以正常运行,采用分析软件ANSYS对水下高速航行器壳体的卡箍连接强度进行了研究。考虑到实际问题的复杂性,首先建立了整个壳体的三维有限元模型,初步分析了壳体应力的大致分布;然后利用子模型技术以及非线性有限元技术,建立了壳体卡箍连接部位的有限元子模型,进一步分析了壳体间连接的接触强度。以有限的计算机资源,得到较为准确的结果。分析结果表明在常态下壳体结构联结强度较好,并进一步预估了壳体的极限载荷。为航行器壳体的结构设计以及优化提供了理论依据。

“柔性边界”在城市设计中的运用

城市中的边界地带往往被人忽视。引入作为联结体的“ 柔性边界”的设计方法，结合一次国际设计竞赛的体会，简述其在城市设计中的作用。

基于符号有序二叉决策图的装配序列生成技术

为提高装配序列规划求解效率和自动化水平,给出了装配体联结图模型、干涉向量和接触向量模型的有序二叉决策图描述,建立了基于符号有序二叉决策图模型及操作的可行装配序列生成技术。结合实例验证了基于有序二叉决策图的装配体模型和可行装配序列生成技术的正确性和可行性。

中介论的意义与作用

中介,即矛盾中的联结体和转化的中间过程,是事物间相互作用的关系。中介论源出于黑格尔,以后经由恩格斯、列宁等先哲们加以继承和发展,成为辩证法对立统一学说中的一个重要组成部分。然而,中介论思想并未引起人们的广泛关注。本文试对此作一初步探讨。 一。

长沙市农业产业化助力农民增收的路径探析

农业产业化发展不仅是乡村振兴战略实施的成果之一,也是提高农民收入的一项重要举措。随着农业产业化进程推进,资金投入少、组织经营分散、农产品竞争力差、农业基础设施建设不健全、农民素质不高等问题成为制约长沙市农业产业化发展的主要因素,为了更好地促进农民增收,加快农业产业化发展,针对长沙市农业发展中存在的问题,提出了有针对性的解决建议,供交流借鉴。

Trust Management Mechanism for Internet of Things

Trust management has been proven to be a useful technology for providing security service and as a consequence has been used in many applications such as P2P, Grid, ad hoc network and so on. However, few researches about trust mechanism for Internet of Things （IoT） could be found in the literature, though we argue that considerable necessity is held for applying trust mechanism to IoT. In this paper, we establish a formal trust management control mechanism based on architecture modeling of IoT. We decompose the IoT into three layers, which are sensor layer, core layer and application layer, from aspects of network composition of loT. Each layer is controlled by trust management for special purpose： self-organized, affective routing and multi-service respectively. And the final decision-making is performed by service requester according to the collected trust information as well as requester＇ policy. Finally, we use a formal semantics-based and fuzzy set theory to realize all above trust mechanism, the result of which provides a general framework for the development of trust models of IoT.

An Open Architecture for Converged Internet of Things

An open architecture for converged Internet of Things (IoT) is proposed in this paper.By using this model,the various and huge amount of data can be converted into converged data and then encapsulated as service packages.Moreover,a Representational State Transfer (REST) platform has been implemented in the lab environment.The merit of this architecture is the enhancement of data efficiency.Experimental results are provided to show the benefits of the proposed architecture.

机械可靠性在高压电器设计中的应用研究

随着我国社会经济的高速发展,高压电器在城市建设中的数量也在不断增加。机械可靠性在针对高压电器的设计中发挥着至关重要的作用。为提升高压电器设计的科学性与有效性,保证高压电器的安全运行,需要工作人员强化对机械可靠性的研究与分析,明确机械可靠性与高压电器设计的关系以及其在高压电器设计中应用的具体方法,推动高压电器设计工作顺利有序地进行,促进我国高压电器设计行业的繁荣发展。

Smart Grids with Intelligent Periphery:An Architecture for the Energy Internet

A future smart grid must fulfill the vision of the Energy Internet in which millions of people produce their own energy from renewables in their homes, offices, and factories and share it with each other. Electric vehicles and local energy storage will be widely deployed. Internet technology will be utilized to transform the power grid into an energysharing inter-grid. To prepare for the future, a smart grid with intelligent periphery, or smart GRIP, is proposed. The building blocks of GRIP architecture are called clusters and include an energy-management system （EMS）-controlled transmission grid in the core and distribution grids, micro-grids, and smart buildings and homes on the periphery; all of which are hierarchically structured. The layered architecture of GRIP allows a seamless transition from the present to the future and plug-and-play interoperability. The basic functions of a cluster consist of （1） dispatch, （2） smoothing, and （3） mitigation. A risk-limiting dispatch methodology is presented; a new device, called the electric spring, is developed for smoothing out fluctuations in periphery clusters; and means to mitigate failures are discussed.

Evolutionary selection on synonymous codons in RNA G-quadruplex structural region

To investigate how synonymous codons have been adapted to the formation of ribonucleic acid(RNA)G-quadruplex(rG4)structure,a computational searching algorithm G4Hunter was applied to detect rG4 structures in protein-coding sequences of mRNAs in five eukaryotic species.The native sequences forming rG4s were then compared with randomized sequences to evaluate selection on synonymous codons.Factors that may influence the formation of rG4 were also investigated,and the selection pressures of rG4 in different gene regions were compared to explore its potential roles in gene regulation.The results show universal selective pressure acts on synonymous codons in rG4 regions to facilitate rG4 formation in five eukaryotic organisms.While G-rich codon combinations are preferred in the rG4 structural region,C-rich codon combinations are selectively unfavorable for rG4 formation.Gene's codon usage bias,nucleotide composition,and evolutionary rate can account for the selective variations on synonymous codons among rG4 structures within a species.Moreover,rG4 structures in the translational initiation region showed significantly higher selective pressures than those in the translational elongation region.

Cognitive Network Management in Internet of Things

The wide variety of smart embedded computing devices and their increasing number of applications in our daily life have created new op- portunities to acquire knowledge from the physical world anytime and anywhere, which is envisioned as the＂Internet of Things＂ （IoT）. Since a huge number of heterogeneous resources are brought in- to IoT, one of the main challenges is how to effi- ciently manage the increasing complexity of IoT in a scalable, flexNle, and autonomic way. Further- more, the emerging IoT applications will require collaborations among loosely coupled devices, which may reside in various locations of the Inter- net. In this paper, we propose a new IoT network management architecture based on cognitive net- work management technology and Service-Orien- ted Architecture to provide effective and efficient network management of loT.

Smart Service System(SSS)：A Novel Architecture Enabling Coordination of Heterogeneous Networking Technologies and Devices for Internet of Things

In Internet of Things(IoT), the devices or terminals are connected with each other, which can be very diverse over the wireless networks. Unfortunately, the current devices are not designed to communicate with the collocated devices which employ different communication technologies. Consequently, the communication between these devices will be realized only by using the gateway nodes. This will cause the inefficient use of wireless resources. Therefore, in this paper, a smart service system(SSS) architecture is proposed, which consists of smart service terminal(SST), and smart service network(SSN), to realize the Io T in a general environment with diverse communication networks, devices, and services. The proposed architecture has the following advantages: i) the devices in this architecture cover multiple types of terminals and sensor-actuator devices; ii) the communications network therein is a converged network, and will coordinate multiple kinds of existing and emerging networks. This converged network offers ubiquitous access for various sensors and terminals; iii) the architecture has services and applications covering all smart service areas. It also provides theadaptability to new services and applications. A SSS architecture-based smart campus system was developed and deployed. Evaluation experiments of the proposed smart campus system demonstrate the SSS's advantages over the existing counterparts, and verify the effectiveness of the proposed architecture.

Structure and magnetic behavior of a trinuclear Mn(Ⅱ)coordination complex with EDTA-ligand

A trinudear Mn（II） coordination complex Mna （HEDTA）2-10H20 （EDTA=ethylene diamine tetraacetic acid） 1 has been synthesized and characterized by X-ray crystal structure determination. In addition, IR spectrum, thermogravimetric analysis, electron paramagnetic resonance （EPR） spectra and magnetic susceptibility of this complex are discussed. X-ray determination indicates that six- and seven-coordinate modes between Mn（Yl） and H4EDTA exist alternately in 1. Furthermore, detailed discussion of magnetic ordering in tile temperature range of 2-300 K reveals the antiferromagnetic interactions in the complex.

Synthesis and Crystal Structure of {Cu_2(pdc)_2(4,4'-bipy)(H_2O)·3H_2O}_2

The title compound {Cu2(pdc)2(4,4?-bipy)(H2O)3H2O}2 1 (H2pdc = pyridine-2,6- dicarboxylic acid, also known as dipicolinic acid; 4,4?-bipy = 4,4?-bipyridine) has been synthesized by the hydrothermal reaction and its structure was determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group Pi with a = 7.2278(3), b = 10.6259(4), c = 17.7614(6) ? a = 79.5990(10), = 83.6300(10), ? = 71.8280(10)o, V = 1272.60(8) ?, C48H44Cu4N8O24, Mr = 1371.07, Z = 1, Dc = 1.789 g/cm3, = 1.747 mm-1, F(000) = 696, R = 0.0397 and wR = 0.1137 for 3938 observed reflections (I > 2s(I)). There are two kinds of Cu coordination environments, and each central copper(II) atom is five-coordinated in a distorted square-based pyramidal coordination geo- metry. Four copper(II) atoms are linked by four pdc and two 4,4?-bipy ligands to form an annular rectangle structure. Extensive hydrogen-bonding interactions involving carboxylate O atoms as well as coordinated and free water molecules lead to the formation of a three-dimensional network struc- ture.

A multi-Agent system architecture for geographic information gathering

World Wide Web (WWW) is a vast repository of information, including a great deal of geographic information. But the location and retrieval of geographic information will require a significant amount of time and effort. In addition, different users usually have different views and interests in the same information. To resolve such problems, this paper first proposed a model of geographic information gathering based on multi-Agent (MA) architecture. Then based on this model, we construct a prototype system with GML (Geography Markup Language). This system consists of three tiers-Client, Web Server and Data Resource. Finally, we expatiate on the process of Web Server.

Synthesis and Crystal Structure of Pyridine-2,6-dicarboxylate Vanadium Complex:[(Pyridine-2,6-dicarboxylate)VO_2]_2[4,4'-bipyridine]·4H_2O

Crystal structure of pyridine-2,6-dicarboxylate(dipc) vanadium complex:[(dipc)VO_2]_2( 4, 4'-bipyridine)·4H_2O(M_r=724.34) is monoclinic with space group C2/c and a=25.857(8),b=6.896(1),c=16.267(5),β=106.27(4)°,V=2784.62 D_c=1.73 g/cm￣3,F(000)=1472,Z=4.The structural solutions and refinements based on 1661 reflections (I>2σ(I))converged at R=0. 043.The coordinated number of vanadium atom is 5,the geometrical form of the five atoms are coordinated to the vanadium atom is a distorted tetragonal bipyramid of which the four coordinated atoms O(3),O(5),N(1) and O(2) make up the equatorial plane,while the other coordinated atom O(1) is to occupy the apex.

Synthesis and Crystal Structure of N,N'-Diphenyl-3, 6-diethyl-1,4-dihydro-s-tetrazine-1,4-dicarbonamide

The crystal structure of the title compound N,N-bisphenyl-3,6-diethyl-1,4- dihydro-s-tetrazine-1,4-dicarbonamide (C20H22N6O2, Mr = 378.44) has been prepared and determi- ned by single-crystal X-ray diffraction. The crystal is of orthorhombic, space group Pbca with a = 16.287(2), b = 11.347(4), c = 20.975(4) ? V = 3876.4(16) ?, Z = 8, Dc = 1.297 g/cm3, F(000) = 1600, m = 0.088 mm-1, MoKa radiation (l = 0.71073 ?. The structure was refined to R = 0.0337 and wR = 0.1038 for 1952 observed reflections with I > 2s(I). X-ray diffraction analysis reveals that two amide groups are located at the 1 and 4 positions, and the tetrazine ring itself shows a boat conformation.

Association between gene polymorphisms of vitamin D receptor and pulmonary tuberculosis susceptibility:a meta-analysis

The vitamin D receptor （VDR） gene is a primary candidate gene for tuberculosis susceptibility, but results of previous studies are somewhat contradictory and underpowered. Thus, it is essential to further explore the association between VDR gene polymorphisms and risk of pulmonary tuberculosis （PTB）. Methods： A systematic review and meta-analysis about the association between Fok[, TaqI, Apal and Bsm[ polymorphisms and PTB susceptibility was conducted. Statistical Package for Social Science （Version 13.0） and Review Manager （Version 4.2, The Cochrane Collaboration） were used to analyze the data reported in studies. Results： A total of 13 studies with 2 262 cases and 2 833 controls were involved in the FokI polymorphism, and the results showed FokI polymorphism was associated with PTB susceptibility （allele f vs F： OR=1.12, 95% CI=[1.02, 1.23]; the additive effect model ff vs FF： OR=1.40, 95%CI=[1.10, 1.77]; the recessive genetic model firs Ff＋FF： OR=1.39, 95%CI=[1.12, 1.71]）. No significant associations were observed between TaqI （15 studies with 3 031 cases and 3 132 controls）, ApaI （7 studies with 1 495 cases and 1 922 controls）, BsmI （6 studies with 919 cases and 1 250 controls） variants and PTB susceptibility. Conclusion： We found variant Fokl polymorphism of VDR gene may play a risky role in PTB development, and the genetic model was presumed to be recessive.

Coordination Triangular Prism of Bisilver Complex with Triply-bridged of Bis(diphenylphosphino)amine

The binuclear complex [Ag2(m-Ph2PNHPPh2)3](ClO4)2CH2Cl2CH3OH (Ph2PNHP- Ph2 = bis(diphenylphosphino)amine) was prepared from the reaction of AgClO4 with bis- (diphenylphosphino)amine in equimolar ratio through self-assembly. The coordination cation affords a triply-bridging [Ag2L3]-type coordination moiety. The silver atom is in a trigonal planar environment with P3 coordination chromophore. The complex (C74H69Cl4N3O9P6Ag2) crystallizes in monoclinic, space group Cc with a = 18.3738(1), b = 20.0207(4), c = 20.5422(4) ? b = 95.829(1), V = 7517.5(2) 3, Z = 4, Mr = 1687.68, Dc = 1.491 g/cm3, F(000) = 3432, m = 0.848 mm-1, the final R = 0.0460 and wR = 0.0935 for 7005 observed reflections with I > 2s(I).

Synthesis and Characterization of New Palladium（ll） Complexes Containing 4,5-dimethyl-2,2＇-bipyridine： X-ray Crystal Structure of Bis（4-methyl pyrdine）-4,5- dimethyl-2,2＇-bipyridine palladium （11） Perchlorate

New heteroleptic and homoleptic complexes of the type[Pd（4,5-dmbipy）C12], [Pd（4,5-dmbipy）L2], and [Pd（4,5-dimebipy）2]2＋ （L = Pyridine or 4-methylpyridine（4-picoline）, bipy = 2,2＇-bipyridine, and 4,5-dimebipy = 4,5-dimethyl-2,2＇-bipyridine） were synthesized and characterized by IH NMR and elemental analysis. The crystal structure of bis（4-methylpyridine）-4,5- dimethyl-2,2＇-bipyridinepalladium（II）perchlorate [Pd（4,5-dmbipy）（4-pic）2]（CIO4）2 was also determined by single crystal X-ray diffraction. This complex crystallized in the triclinic crystal system and space group PI with a = 9.562 （2）, b = 11.326 （4）, c = 15.0120 （10） A°; α = 70.940°, β= 77.60 （2）, γ= 67.86 （2） and z = 4. The Pd （II） in square planar environment showed a small distortion towards tetrahedral through one coordinated bipyridine ring twisting with respect to the other.