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排序方式: 共有169条查询结果,搜索用时 234 毫秒
101.
The mechanical properties of transformation induced plasticity (TRIP) steel are strongly affected by the conditions of iso-thermal bainitic processing. The multiphase microstructure of TRIP steel under different conditions of isothermal bainitic processing was investigated using OM,SEM,XRD and TEM. The volume fraction of retained austenite and the carbon content in austenite were determined quantitatively using X-ray diffraction patterns. The relationship between mechanical properties and isothermal bainitic processing parameters was investigated. The stability of retained austenite was analyzed by the volume fraction of retained austenite and the carbon content in retained austenite. The experimental results show that the multiphase microstructure consists of ferrite,bainite and metastable retained austenite.To obtain good mechanical properties,the optimal conditions of isothermal bainitic temperature and holding time are 410-430℃ and 180-240 s,respectively. After isothermal bainitic processing under the optimal conditions,the corresponding volume fraction of retained austenite is 5vol%-15vol%,which can provide enough retained austenite and plastic stability for austenite with high carbon content. 相似文献
102.
Chensha Li Binsong Wang Weizhe Lu Dazhi Wang Zhi Li Zechao Di Ji Liang 《矿物冶金与材料学报》2007,14(6):573-579
Antistatic polymer fibers were investigated by using carbon nanotubes (CNTs) to enhance the antistatic ability of inner antistatic agents based on the mechanism of attracting moisture by polar radical groups. It is indicated that the antistatic ability of the fibers filled with composite antistatic agents that contain CNTs and organic antistatic agents was superior to that of the fibers filled either with pure organic antistatic agents or pure CNTs. The antistatic ability of the composite antistatic agent fabricated by an in situ process was superior to that of the composite antistatic agent fabricated by direct dispersing CNTs in the antistatic agent carrier. Moreover, the heat-treated CNTs could further enhance the antistatic effect compared with the initial CNTs. The antistatic effect is significantly influenced by the content of CNTs in the composite antistatic agent. 相似文献
103.
基于相似理论的系统仿真可信性分析 总被引:6,自引:0,他引:6
基于相似理论的基本原理 ,讨论系统仿真的可信性问题 ,提出基于相似理论的系统仿真可信性分析的基本思想和方法 . 相似文献
104.
Hairpin RNA: a secondary structure of primary importance 总被引:4,自引:0,他引:4
An RNA hairpin is an essential secondary structure of RNA. It can guide RNA folding, determine interactions in a ribozyme,
protect messenger RNA (mRNA) from degradation, serve as a recognition motif for RNA binding proteins or act as a substrate
for enzymatic reactions. In this review, we have focused on cis-acting RNA hairpins in metazoa, which regulate histone gene expression, mRNA localization and translation. We also review
evolution, mechanism of action and experimental use of trans-acting microRNAs, which are coded by short RNA hairpins. Finally, we discuss the existence and effects of long RNA hairpin
in animals. We show that several proteins previously recognized to play a role in a specific RNA stem-loop function in cis were also linked to RNA silencing pathways where a different type of hairpin acts in trans. Such overlaps indicate that the relationship between certain mechanisms that recognize different types of RNA hairpins is
closer than previously thought.
Received 21 November 2005; received after revision 3 January 2006; accepted 11 January 2006 相似文献
105.
Dowling DP Di Costanzo L Gennadios HA Christianson DW 《Cellular and molecular life sciences : CMLS》2008,65(13):2039-2055
Novel structural superfamilies can be identified among the large number of protein structures deposited in the Protein Data Bank based on conservation of fold in addition to conservation of amino acid sequence. Since sequence diverges more rapidly than fold in protein Evolution, proteins with little or no significant sequence identity are occasionally observed to adopt similar folds, thereby reflecting unanticipated evolutionary relationships. Here, we review the unique alpha/beta fold first observed in the manganese metalloenzyme rat liver arginase, consisting of a parallel eight-stranded beta-sheet surrounded by several helices, and its evolutionary relationship with the zinc-requiring and/or iron-requiring histone deacetylases and acetylpolyamine amidohydrolases. Structural comparisons reveal key features of the core alpha/beta fold that contribute to the divergent metal ion specificity and stoichiometry required for the chemical and biological functions of these enzymes. 相似文献
106.
Vicinanza M D'Angelo G Di Campli A De Matteis MA 《Cellular and molecular life sciences : CMLS》2008,65(18):2833-2841
Membrane trafficking is crucial in the homeostasis of the highly compartmentalized eukaryotic cells. This compartmentalization
occurs both at the organelle level, with distinct organelles maintaining their identities while also intensely interchanging
components, and at a sub-organelle level, with adjacent subdomains of the same organelle containing different sets of lipids
and proteins.Acentral question in the field is thus how this compartmentalization is established and maintained despite the
intense exchange of components and even physical continuities within the same organelle. The phosphorylated derivatives of
phosphatidylinositol, known as the phosphoinositides, have emerged as key components in this context, both as regulators of
membrane trafficking and as finely tuned spatial and temporal landmarks for organelle and sub-organelle domains. The central
role of the phosphoinositides in cell homeostasis is highlighted by the severe consequences of the derangement of their metabolism
caused by genetic deficiencies of the enzymes involved, and from the systematic hijacking of phosphoinositide metabolism that
pathogens operate to promote their entry and/or survival in host cells. (Part of a Multi-author Review) 相似文献
107.
Zeolite derived from coal-based solid wastes(coal gangue and coal fly ash) can overcome the environmental problems caused by coal-based solid wastes and achieve valuable utilization. In this paper, the physicochemical properties of coal gangue and coal fly ash are introduced. The mechanism and application characteristics of the pretreatment processes for zeolite synthesis from coal-based solid wastes are also introduced. The synthesis processes of coal-based solid waste zeolite and their advanta... 相似文献
108.
Hong-ming Long Xue-jian Wu Tie-jun Chun Zhan-xia Di Ping Wang Qing-min Meng 《矿物冶金与材料学报》2016,23(11):1239-1243
The iron ore sintering process is the main source of SO2 emissions in the iron and steel industry. In our previous research, we proposed a novel technology for reducing SO2 emissions in the flue gas in the iron ore sintering process by adding urea at a given distance from the sintering grate bar. In this paper, a pilot-scale experiment was carried out in a commercial sintering plant. The results showed that, compared to the SO2 concentration in flue gas without urea addition, the SO2 concentration decreased substantially from 694.2 to 108.0 mg/m3 when 0.10wt% urea was added. NH3 decomposed by urea reacted with SO2 to produce (NH4)2SO4, decreasing the SO2 concentration in the flue gas. 相似文献
109.
At present, robot embedded systems have some common problems such as closure and poor dynamic evolution. Aiming at resolving this situation, our paper focuses on improvements to the robot embedded system and sets up a new robot system architecture, and we propose a syncretic mechanism of a robot and Soft Man(SM). In the syncretic system, the structural organization of the Soft Man group and its modes are particularly important in establishing the task coordination mechanism. This paper, therefore, proposes a coordination organization model based on the Soft Man group, and studies in detail the process of task allocation for resource contention, which facilitates a rational allocation of system resources. During our research, we introduced Resource Requirement Length Algorithm(RRLA) to calculate the resource requirements of the task and a resource conformity degree allocation algorithm of Resource Conformity Degree Algorithm(RCDA) for resource contention. Finally, a comparative evaluation of RCDA with five other frequently used task allocation algorithms shows that RCDA has higher success and accuracy rates with good stability and reliability. 相似文献
110.
MA Deardorff M Bando R Nakato E Watrin T Itoh M Minamino K Saitoh M Komata Y Katou D Clark KE Cole E De Baere C Decroos N Di Donato S Ernst LJ Francey Y Gyftodimou K Hirashima M Hullings Y Ishikawa C Jaulin M Kaur T Kiyono PM Lombardi L Magnaghi-Jaulin GR Mortier N Nozaki MB Petersen H Seimiya VM Siu Y Suzuki K Takagaki JJ Wilde PJ Willems C Prigent G Gillessen-Kaesbach DW Christianson FJ Kaiser LG Jackson T Hirota ID Krantz K Shirahige 《Nature》2012,489(7415):313-317