共查询到20条相似文献,搜索用时 93 毫秒
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本文列出了国内一些热连轧机地下卷取机卷筒传动的一些参数,并作了一些比较,对卷取力矩的计算、张力控制系统及功能的分担作了说明。 相似文献
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作为材料设计基础的相图研究 总被引:4,自引:1,他引:3
介绍了现代材料设计与相图研究之间的关系,强调了计算相图的出现使相图研究成为材料的设计的一部分,相图计算程序系统的另一重要功能是评估和优化热力学参数,以双相纳米材料、宽滞后形状记忆合金、钕铁硼永磁合金、钛铝金属间化合物和低温用钢的研究开发为例,说明了相图研究在材料设计上的重要作用。 相似文献
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斜轧穿孔机孔型优化系统的研制 总被引:2,自引:1,他引:1
开发了主要功能为穿孔工具优化设计、穿孔调整参数优化计算以及毛管横向壁厚均匀性分析的斜轧穿孔机孔型优化系统。该系统不仅可用于斜轧穿孔工具设计和离线分析,还可用于指导穿孔机操作。 相似文献
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攀钢1220mm冷连轧机主轧机组控制系统为两级计算机系统:一级控制计算机完成基础自动化控制,实现轧线设备的控制与实测数据的采集等功能;二级控制计算机完成过程控制,进行模型计算、轧制数据管理等功能。冷连轧机的轧制规程设定计算模型一般分为两种:一种是以轧制理论为主的理论模型;另一种是以实际轧制数据为主的经验模型。在实际使用时,这两种模型相互联系,只是侧重面不同。攀钢1220mm冷连轧机的设定模型是以经验为主的模型。它将标准轧制参数以表格形式存储,在设定计算时,根据来料情况进行修正计算,以得出相应的轧… 相似文献
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马钢单机架可逆式轧机过程控制系统使用了日立公司的表格式轧制模型。介绍了该模型参数计算公式,模型参数计算流程及自适应学习功能。 相似文献
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Comparison of interaction energy between an oligonucleotide and a DNA-binding ligand in the minor and major groove modes was made by use of restrained molecular dynamics. Distortion in DNA was found for the major groove mode whereas less significant changes for both ligand and DNA were detected for the minor groove binding after molecular dynamics simulation. The conformation of the ligand obtained from the major groove modes resembles that computed with the ligand soaked in water. The van der Waals contact energy was found to be as significant as electrostatic energy and more important for difference in binding energy between these two binding modes. The importance of van der Waals force in groove binding was supported by computations on the complex formed by the repressor peptide fragment from the bacteriophage 434 and its operator oligonucleotide. 相似文献
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Shude Ji Yue Wang Zhengwei Li Yumei Yue Peng Chai 《Transactions of the Indian Institute of Metals》2017,70(6):1417-1430
Using LY12 aluminum alloy as the research object, material flow behavior of refill friction stir spot welding process is simulated. The simulation results are investigated by studying the macrostructure and microstructure of the refill friction stir spot welding joints. Effects of tool geometries on material flow are mainly discussed. Results show that bonding ligament and grains in different regions of the stir zone are affected by the material flow behavior. Rational groove on the sleeve can increase the material flow velocity. From the viewpoint of reducing the unfavorable bonding ligament, the groove on the sleeve inner wall is better than the smaller width groove on the sleeve outer wall. Compared with the concentric circle grooves on the sleeve bottom, the scrolled groove is more beneficial to decrease the bonding ligament thickness and increase the welding spot area. Disregarding the higher heat input, sleeve with bigger outer diameter greatly increases the flow velocity and the welding spot area compared to changing the groove geometry. 相似文献
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文章介绍了泰国泰龙高速棒材轧机旋转导槽式棒材收集系统的自动化控制。阐述了利用轴定位模块对旋转导槽的控制思想。以SIEMENS公司S7-300系列PLC的FM354轴定位模块为例,从硬件上剖析轴定位模块。讲述了轴定位模块的软件参数化及运动程序的编制过程。说明了轴定位模块可应用的领域。 相似文献
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B Feng A Gorin A Kolbanovskiy BE Hingerty NE Geacintov S Broyde DJ Patel 《Canadian Metallurgical Quarterly》1997,36(45):13780-13790
A combined NMR-computational approach was employed to determine the solution structure of the (-)-trans-anti-[BP]dG adduct positioned opposite a -1 deletion site in the d(C1-C2-A3-T4-C5- [BP]G6-C7-T8-A9-C10-C11).d(G12-G13-T14-A15-G1 6-G17-A18-T19-G20-G21) sequence context. The (-)-trans-anti-[BP]dG moiety is derived from the binding of the (-)-anti-benzo[a]pyrene diol epoxide [(-)-anti-BPDE] to N2 of dG6 and has a 10R absolute configuration at the [BP]dG linkage site. The exchangeable and non-exchangeable protons of the benzo[a]pyrenyl moiety and the nucleic acid were assigned following analysis of two-dimensional NMR data sets in H2O and D2O solution. The solution conformation has been determined by incorporating intramolecular and intermolecular proton-proton distances defined by lower and upper bounds deduced from NOESY spectra as restraints in molecular mechanics computations in torsion angle space followed by restrained molecular dynamics calculations based on a NOE distance and intensity refinement protocol. Our structural studies establish that the aromatic BP ring system intercalates into the helix opposite the deletion site, while the modified deoxyguanosine residue is displaced into the minor groove with its face parallel to the helix axis. The intercalation site is wedge-shaped and the BP aromatic ring system stacks over intact flanking Watson-Crick dG.dC base pairs. The modified deoxyguanosine stacks over the minor groove face of the sugar ring of the 5'-flanking dC5 residue. The BP moiety is positioned with the benzylic ring oriented toward the minor groove and the distal pyrenyl aromatic ring directed toward the major groove. This conformation strikingly contrasts with the corresponding structure in the full duplex with the same 10R (-)-trans-anti-[BP]dG lesion positioned opposite a complementary dC residue [de los Santos et al. (1992) Biochemistry 31, 5245-5252); in this case the aromatic BP ring system is located in the minor groove, and there is no disruption of the [BP]dG.dC Watson-Crick base pairing alignment. The intercalation-base displacement features of the 10R (-)-trans-anti-[BP]dG adduct opposite a deletion site have features in common to those of the 10S (+)-trans-anti-[BP]dG adduct opposite a deletion site previously reported by Cosman et al. [(1994)(Biochemistry 33, 11507-11517], except that there is a nearly 180 degrees rotation of the BP residue about the axis of the helix at the base-displaced intercalation site and the modified deoxyguanosine is positioned in the opposite groove. In the 10S adduct, the benzylic ring is in the major groove and the aromatic ring systems point toward the minor groove. This work extends the theme of opposite orientations of adducts derived from chiral pairs of (+)- and (-)-anti-BPDE enantiomers; both 10S and 10R adducts can be positioned with opposite orientations either in the minor groove or at base displaced intercalation sites, depending on the presence or absence of the partner dC base in the complementary strand. 相似文献
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高强铝合金的激光-MIG复合焊接的实验研究 总被引:1,自引:0,他引:1
以20mm厚的高强铝合金2519-T87为研究对象,研究了激光-MIG复合焊接工艺的工艺参数、坡口形貌以及热处理制度对高强铝合金的平板对接接头的抗拉强度的影响。研究表明:采用类似双U型坡口比国外常用的双V型坡口更有利于复合焊的焊接;保护气体对焊接接头的气孔的形成比较敏感,从而影响焊接接头的抗拉强度,复合焊的保护气体一般采用He气中添加少量的Ar;送丝速度通过改变焊接热输入来影响焊缝组织的晶粒大小以及强化元素的烧损量对焊接接头的强度影响较大。焊后对接头进行合适的热处理,可以显著提升接头的抗拉强度。 相似文献
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棒材同轴复合时芯材与加工工具不接触,其横截面形状及尺寸精度控制难度大,采用方-椭圆孔型轧制时芯材圆度严重超公差。在建立覆材和芯材变形抗力模型的基础上,利用三维弹塑性热力耦合有限元方法对同轴复合棒材热轧变形过程进行数值模拟。分析了轧制孔型、覆材及芯材外形对轧制后芯材变形和形状的影响,用工业试验对模拟计算结果进行验证。结果表明:轧辊孔型设计对芯材不圆度的影响最明显,覆材及芯材外形是次要影响因素。这是因为方-椭圆孔型系统会导致最终轧件在横截面上的非对称等效累积应变分布,以及导致轧后芯材严重不圆。减少K4孔的轧件压下量,增加K3孔轧件压下量,可以改善方-椭圆孔型中轧件变形的对称性,减少芯材不圆度。 相似文献