基于有限元仿真的载重子午线轮胎降噪方法研究

通过有限元仿真分析研究载重子午线轮胎结构对振动噪声的影响。建立了轮胎有限元分析模型并对其合理性进行了试验验证;在原轮胎结构的基础上,对带束层结构和胎面花纹进行优化设计,利用声学仿真软件进行仿真分析,得到了轮胎各设计方案的振动噪声。结果表明,带束层结构和胎面花纹设计均会影响轮胎振动噪声,带束层结构和胎面花纹优化后最大降噪量分别达到3.09和3.9dB。     

定模推件板和动模哈夫斜滑块双向推件注塑模

在分析塑料外壳工艺特性的基础上,优选了注塑模设计方案。论述了模具结构特点和工作原理。该模具采用定模推件板及动模哈夫斜滑块双向推件解决塑件脱模问题。模具结构紧凑,安装操作方便,成型塑件质量好,生产效率高。     

基于仿真分析对轮胎花纹噪声进行优化研究

介绍仿真分析在轮胎花纹降噪设计中的应用。通过采用仿真分析的遗传算法对花纹节距排列和错位进行优化分析,选取最优的设计方案。并以265/60R18 114H XL作为实例分析,将优化设计的产品送西班牙做噪声测试,取得较好的噪声测试结果,比标准值降低了2dB,具有较好的降噪效果。所以仿真分析为轮胎花纹设计提供了一种先进、实用和科学的研究方向和思路,在设计阶段使产品达到最佳性能,缩短研发周期和提高研发质量。     

基于Isight复合材料板弹簧的结构优化设计

本文采用多学科参数优化软件Isight中的Catia、Abaqus组件集成Catia、Abaqus和Isight,构建了基于Isight的多学科参数优化设计平台,通过这一设计平台结合分析设计的思路进行优化设计,实现了对某型号汽车复合材料板弹簧的结构优化设计。研究表明:在以复合板弹簧结构体积最小的前提下,选取合适的设计变量可以显著改善板弹簧的受力状况,板弹簧刚度值可由初始设计出的刚度值900N/mm提高至1101.7N/mm,与本款板弹簧的设计要求刚度值1100±110N/mm相比,误差仅为0.005%,从而为复合材料板弹簧的轻量化设计提供设计依据,复合板弹簧的质量为钢板弹簧的1/5左右,整车减重约67%,起到较好的轻量化设计效果。     

石油化工装置塔内件安装过程中常见问题及处理

塔内件是装置塔器核心设备,大型装置塔内件安装过程中会出现一些问题,对工程产生安全隐患,因此需要对石油化工装置塔内件安装过程中的常见问题进行处理。在塔内件安装过程中,主要存在塔盘水平度出现偏差、支撑结构变形和浮阀不能灵活浮动与开闭的问题。从安装技术方面,可以通过压力容器热处理预防焊接变形,保持塔盘水平度;选择平行弦桁架梁结构作为塔内件支撑,优化支撑结构;优化浮阀塔板尺寸及结构,增加气相流动通道。从质量控制方面,通过规范焊接热处理参数,优化桁架梁设计方案和控制浮阀塔板结构参数,以保证塔内件安装质量。     

石化企业蒸汽动力系统柔性设计

蒸汽动力系统的设计工作是一项复杂的、系统的工程,除了力求实现全周期内总费用最小的经济性目标外,还要保证实际运行过程中的各种工况下的操作柔性。针对石化企业蒸汽动力系统变工况的特点,提出了蒸汽动力系统柔性优化设计策略;将确定性变化需求转化成多周期问题,将不确定性变化需求转化成虚拟的多工况问题,并对连续不确定性和离散不确定性变化分别处理;以经济性和可操作性的最优综合为目标,建立蒸汽动力系统柔性优化设计的大型混合整数线性（MILP）模型,并采用广义Benders分解算法进行求解。采用本文提出的柔性优化设计模型和求解方法,对某炼油厂蒸汽动力系统进行了柔性优化设计,并与传统设计方案和经济性最优的设计方案进行对比。与经济性最优的方案对比结果表明,该优化设计方案总费用增加不多,但实现了在各种变化工况下的安全、稳定、柔性操作;而与传统设计方案对比结果表明,不但提高了各种工况下的操作柔性,而且节省了大量的投资和运行费用,即柔性设计方案具备可操作性和经济性的综合最优性。从而证明了本文提出的柔性设计建模和求解方法的合理性和实用性。     

泡沫塑料在机舱降噪内装饰方面的应用研究

国产螺旋桨运输机的发动机噪声非常大，导致机舱内局部噪声甚至可达90dB，严重影响了机舱内工作人员的正常工作与休息。目前，航空领域降噪的手段除了减少或降低噪声源之外，最普遍的方法就是安装隔声设施和吸声装饰层。国产螺旋桨运输机上现有的降噪手段就是采用复合材料吸声装饰层——褶皱芯夹层内装饰板、蜂窝芯夹层内装饰板。这两种吸声装饰板的降噪效果较明显，但存在工艺复杂、板件重量难以控制等问题。     

ANSYS在化工设备结构优化设计中的应用

优化设计一直是工程界较为关注的领域,文章用 ANSYS 软件对U形管换热器的管板厚度进行了优化设计,结果表明:合理的结构优化设计可以提高安全性和经济性,并为换热器的设计提理论依据.     

循环正交算法优化压裂水平井井网参数

以正交设计原理为基础,通过对正交设计方案进行正交设计再处理,建立了多参数优化设计的循环正交设计方法,利用该方法进行压裂水平井井网参数优化设计,得到了更理想的效果。优化设计结果表明,循环正交设计方法既保留了常规正交算法的优点又能进一步提高优化设计效果,对于油田开发中的多参数优化设计问题具有指导意义。     

浅析开孔率对驼峰板受力的影响

采用ANSYS分析软件对不同开孔率的驼峰板进行应力分析,并对驼峰板典型部位的应力进行线性化,通过对线性化结果的对比和评定,得出合理的驼峰板开孔率范围,以及驼峰板优化设计方案。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料，介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比，介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序，对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。     

Inorganic/organic nanocomposite coatings: The next step in coating performance

Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.