活络模硫化轮胎胶边现象及解决措施

采用活络模硫化子午线轮胎时,由于花纹块间、花纹块与上下胎侧板间及钢圈与胎侧板间存在间隙,胶料由缝隙流出形成胶边。另外,合模时花纹块底面与胎侧板模口处根切胎坯,从而造成花纹块与胎侧板之间存在夹胶,硫化后在胎肩部位也会出现胶边。胶边不仅影响轮胎外观质量,严重时还会影响轮胎的动平稳性能。     

全钢载重子午线轮胎胶边的产生原因及解决措施

分析全钢载重子午线轮胎胶边的产生原因,并提出相应解决措施。除了模具加工精度差外,胎坯材料过多、胎坯周长过大、硫化机合模力偏小、模具装配与润滑保养不到位、硫化机水平度和对中度不好、钢菱圈变形和损伤、硫化定型压力过大、胶囊形状与胎坯形状不匹配等均会造成轮胎胶边,通过采取合理调整胎坯大小和周长、选择适当的合模力、合理设计模具分型面以及模具装配作业符合要求等措施,全钢载重子午线轮胎胶边明显减少。     

子午线轮胎硫化胶边的产生原因及改善措施

分析子午线轮胎硫化胶边的产生原因并提出改善措施。通过采取将模具分型面取胎肩花纹块位置,合理设计胎坯外周长、内衬层宽度和胎侧居中值,规范硫化工艺参数,合理组装硫化模具并进行适宜地维护和保养,以及严格控制生产过程等措施,有效改善了子午线轮胎硫化产生胶边问题。     

活络模硫化子午线轮胎胶边影响因素及解决措施

分析活络模硫化子午线轮胎过程中胶边产生的原因及对轮胎均匀性的影响。通过提高活络模组装精度,减少组装断差,合理预留花纹块间及花纹块与胎侧间的间隙,并确保间隙均一,可减少胶边的产生。在胶边产生后,根据胎面与胎侧结合处胶边的厚度,调整中模套上端调模垫片厚度、合模力和定型压力、使胎坯直径比模具花纹沟底部直径小一些,可减少胶边,提高轮胎外观质量和均匀性。     

全钢轻型载重子午线轮胎高温硫化工艺研究

研究全钢轻型载重子午线轮胎的高温硫化工艺。结果表明,采用高温蒸汽加氮气的硫化工艺,通过调整硫化温度等工艺条件,从轮胎胎肩、胎侧和胎圈部位硫化温度分布和硫化状态进行分析,设计一种适合全钢轻型载重子午线轮胎的高温硫化工艺,可在保证轮胎质量的同时提升轮胎硫化效率。     

硫化工序对全钢载重子午线轮胎均匀性径向跳动值的影响

分析硫化工序中各因素对全钢载重子午线轮胎均匀性径向跳动值的影响。通过把关胎坯和内衬层接头、采用胎坯低点与模具高点互补、硫化工艺定型过程控制补偿低点、胎面胶片补偿等方法,同时严格控制硫化胶囊定型高度和装胎高度,可减小全钢载重子午线轮胎均匀性径向跳动值,提升均匀性合格率。     

全钢载重子午线轮胎上三角胶配方设计研究

从硫化体系、增塑体系和加工助剂三方面对全钢载重子午线轮胎上三角胶配方进行优化设计。结果表明:调整硫化体系以增大多硫键含量,在不影响工艺操作性能的前提下,减小芳烃油和增粘树脂用量,能显著提升全钢载重子午线轮胎上三角胶的耐疲劳性能,轮胎的胎圈耐久性能得到提升。     

圆锥式活络模硫化时出现问题的处理

圆锥面导向活络模具是硫化子午线轮胎的主要设备之一,其型腔的质量直接影响着子午线轮胎的外观质量。 硫化时出现问题主要是轮胎胶边及胎侧出现台阶现象。胶边分5种类型:1.花纹块接触面(立面)之间及上、下侧模花纹块配合处(周边)均出现胶边;2.只花纹块接触面(立面)之间出现胶边;3.上、下侧模与花纹块配合处(下、下周边)均有胶边;4.上侧模与花纹块配合处(上周边)出现胶边;5.下侧模与花纹块配合处(下周边)出现胶边。上述各种问题主要是由模具制造误差、装配不当等几方面原因造成的。     

全钢载重子午线轮胎肩部帘线弯曲问题分析

分析全钢载重子午线轮胎肩部帘线弯曲的产生原因,并提出解决措施.肩部帘线弯曲的主要原因为技术参数设计时成型平宽、胎坯外周长和钢丝圈平面宽设置过大;压延过程中钢丝帘线张力设置不合理,胎面、胎肩垫胶或复合三角胶的口型板磨损,预硫化工艺波动导致钢丝圈硫化程度不足,成型机钢丝圈夹持器以及胎体鼓或定型鼓胎圈撑块定位不准或发生漂移,成型压力过小或压辊压力过大,胎坯存放过程中发生变形以及硫化定型压力过大.采取措施后,可以有效解决全钢载重子午线轮胎肩部帘线弯曲问题.     

全钢子午线轮胎硫化胶边的原因分析及解决措施

分析全钢子午线轮胎硫化胶边的产生原因,并提出相应解决措施。除了采取确保胎坯设计尺寸与模具尺寸匹配度、模具精度及硫化工艺参数符合要求等常规措施外,对于采用两半模硫化的情况,适当调低正硫化氮气压力不仅可改善硫化机合模力偏高和设备负荷较大的问题,还可在确保轮胎性能满足企业标准的前提下有效减少硫化胶边。     

乙苯,苯乙烯的生产及合成乙苯,苯乙烯催化剂的研究进展

苯乙烯是重要的石油化工原料。本文介绍了国内外苯乙烯生产的发展概况，合成乙苯，苯乙烯所用的催化剂种类，并就苯乙烯生产及催化剂的发展趋势提出了自己的观点。     

Synthesis and characterization of homopolymers and copolymers of various acrylates and acrylonitrile

Various homopolymers and copolymers of methyl acrylate, ethyl acrylate, butyl acrylate, and acrylonitrile in different feed ratios were synthesized. These were characterized by IR, ¹³C-NMR, DSC, DTA, and TGA. Spectroscopic characterization helped in differentiating copolymers of different mol ratios. Thermal analysis revealed different degradation patterns for homopolymers and copolymers. The temperature and energy changes associated with various phase transitions were dependent on the chemical composition of homo- and copolymers, as expected. © 1993 John Wiley & Sons, Inc.     

生物质气化及生物质与煤共气化技术的研发与应用

总结了生物质原料的特点及生物质单独气化的缺点;介绍了国内外生物质气化技术及生物质与煤共气化技术的研发与应用现状;分析了在此领域国内外的发展趋势与前景;概括了开展生物质与煤共气化技术研发的意义。     

Electronic structures and reactivities of monometallic and bimetallic clusters of Au and Cu

The variation of the Au 4f binding energy of Au clusters with the cluster size has been established by measuring the binding energies of clusters whose size distributions were independently determined by HREM and STM. The binding energy increases significantly when the cluster size is less than 2 nm. Au-Cu bimetallic clusters of the composition Cu₃Au have been deposited for the first time on carbon substrates. The shifts in the core level binding energies of the bimetallic clusters show the effect of alloying in the case of large clusters, but show effects of both alloying and cluster size in the case of the small clusters. The interaction of CO with Cu₃Au clusters is stronger than with a bulk Cu metal. The interaction of CO with small Cu clusters also seems to be stronger than with bulk Cu or with large Cu clusters.     

钾盐资源及钾肥供需情况分析及预测

阐述了国内外钾盐资源及钾肥生产现状,对国内外钾盐的供需形势进行了分析及预测,从资源、原材料、国际市场三方面提出了解决我国钾盐短缺的措施。     

Kinetics and Mechanism of Oxidation of Mono- and Polyacetals

Abstract

Kinetics and mechanisms of oxidation of 6 acetals by molecular oxygen and ozone in liquid phase have been studied. Reaction with molecular oxygen (70°C, 15–16 hr) leads to the formation monoethers of the corresponding glycols with 68–90% selectivity. Salts of metals and complexes with crown-ethers have increased the reaction rate significally. Ozone have reacted with acetals with formation similar products. The mechanisms of intermediate stages have been proposed.     

Comparison of the Adhesion and Cohesion of Triblock and Random Copolymers of Styrene and Butadiene

A substantially greater detachment energy is required to strip a polyethylene tereph-thalate (Mylar) film from a styrene-butadiene-styrene (SBS) triblock copolymer compared to that for peeling from a random styrene-butadiene (SBR) copolymer. This is true even though the intrinsic interaction between the Mylar and each elastomer is expected to be similar because of their virtually identical chemical composition. It is proposed that this difference in peel strength (between the SBS and SBR) is a consequence of the much higher dissipative capacity of the former elastomer. Another manifestation of this is the higher cohesive tear strength of the SBS compared to the SBR. Extents of energy dissipation within each elastomer during detachment of the Mylar adherend are consistent with the hypothesis that the average maximum stress experience before detachment is some similar fraction of each elastomer's tensile strength.     

Wetting properties of homopolymers and copolymers of pentafluorostyrene and methylacrylate and homopolymer blends

Polypentafluorostyrene (PPFS), polymethylacrylate (PMA), and poly(pentafluorostyrene-co-methylacrylate), poly(PFS-co-MA) were prepared and the wetting characteristics of polymer blends of PPFS and PMA were compared with that of poly(PFS-co-MA) via contact angle measurements. The critical surface tension of polypentafluorostyrene was found to be 22.6 dyne/cm, which is comparable to the value reported for polytrifluoroethylene (22 dyne/cm). The critical surface tension of poly(PFS-co-MA) is not linearly related to its composition. The polymer blends of PPFS and PMA exhibit significant surface enrichment of the fluoropolymer. The harmonic-mean method¹ was employed to determine surface tensions of these polymers and many known polymers. It is found that the method produces useful surface tension data provided the contact angle values are derived from testing liquids of dissimilar polarity.     

责任和责任心的涵义与结构

责任是人应主动承担的角色义务和对其因过失所造成后果应承担的责罚.有两层涵义:一是义务;二是后果.责任心是个体自觉做好分内事务和履行道德义务的心理倾向,是个性心理品质成分中自我特征维度上的重要内容.责任心具有两个方面的涵义:一是角色分内职责;二是角色道德义务.责任心是一种通过责任认知、责任个性和责任适应的动态形式表现出来的静态品质,责任心是责任心过程结构与责任心关系结构相互制约、相互影响的统一体.     

二甲基二烯丙基氯化铵和丙烯酰胺的合成及应用

用复合引发体系(过硫酸盐-偶氮类引发剂)和脂肪胺类氧化还原体系引发,在实验室获得了单体转化率≥98%,特性粘数高于13.6 dL/g的阳离子共聚物PDA,探讨了控制聚合物分子量的影响因素.