LED非球面透镜注射压缩成型工艺稳健性优化分析

采用稳健设计方法,以发光二极管（LED）非球面透镜折射率变化为实验目标,以压缩距离、压缩速度、压缩力、保压压力、熔体温度、冷却时间、注射速率为影响因素,设计了L27(37)正交试验矩阵,并对透镜的注射压缩成型过程采用Moldflow2015软件模拟分析。结果表明,最优工艺参数组合为A3B1C2D3E3F2G2;熔体温度对透镜折射率的影响最大,注射速率次之,压缩距离、冷却时间、保压压力影响较小,压缩速度、压缩力影响最小;优化后采用更高的熔体温度和较快的注射速率,有利于减小透镜的体积收缩,改善透镜内部残余应力,折射率变化减小了45 %,翘曲变形量减小了4.3 %。     

透镜注射成型工艺的稳健设计与正交设计对比

采用稳健设计与正交设计,以LED非球面透镜的翘曲变形、折射指数变化、体积收缩率为实验目标,注射时间、V/P转换、保压时间、熔体温度、冷却时间、保压压力、模具温度为实验因素,对透镜的注射成型过程采用Moldflow2015软件进行模拟分析与对比。结果表明:稳健设计的信噪比法最佳工艺参数组合为A2B3C3D1E2F3G2,正交设计的方差法最佳工艺参数组合为A1B3C2D3E2F3G1,信噪比法与方差法得到的各因素影响权重排序相同,采用稳健设计透镜的最大翘曲变形量为0.0166 mm、最大折射指数变化0.0186、最大体积收缩率为10.49%、最高温度为215℃,采用正交设计透镜的最大翘曲变形量为0.0299 mm、最大折射指数变化为0.0327、最大体积收缩率为13.98%、最高温度为255℃,稳健设计得到的透镜最佳工艺参数组合要比传统的正交设计优越,可以更有效地提高LED非球面透镜的光学性能和成型质量。     

新型建筑用碳纤维复合材料的注塑成型与工艺优化

采用4因素4水平的正交实验法,考察了熔体温度(A)、注射压力(B)、保压压力(C)、注射时间(D)、对建筑用碳纤维复合材料试件翘曲总变形、体积收缩率和缩痕的影响,优化了建筑用碳纤维/聚碳酸酯基复合材料的成型工艺。结果表明,各因素对翘曲总变形和缩痕影响从高至低顺序为:ACBD,对体积收缩率影响从高至低顺序为ABCD,采用综合平衡法优化碳纤维/聚碳酸酯基复合材料的最佳注塑成型工艺参数组合为A4B1C1D2,即熔体温度为305℃、注射压力为155MPa、保压压力为85MPa、注射时间为3s。     

注射压缩成型LED透镜光学性能分析

针对注射压缩成型的发光二极管（LED）透镜,采用L18(37)正交实验矩阵及模拟优化获得A3B2C2D2E2F3G1最佳成型工艺参数组合,并对透镜进行了光学性能测试。结果表明,工艺参数中的压缩速度增大和注射速率降低,透镜的内部残余应力和折射率变化减小而光学性能提高;采用热流道注射压缩成型的透镜与冷流道的相比,折射率变化降低,冷流道透镜的透光率和最大光强为93.1 %和590.3 cd,热流道透镜的的透光率和最大光强为97.5 %和665.3 cd,热流道透镜的透光率和光强分别比冷流道的提高4.4 %和75 cd,热流道注射压缩成型加工的LED透镜在光学性能方面比冷流道的优越。     

汽车储物盒导轨鲁棒优化设计

汽车储物盒导轨在与储物盒配合使用时,需保证较高的形状及尺寸精度,但是当模具温度、保压压力等工艺参数设置不合理时,其在注塑成型过程中易产生翘曲变形,导致无法正常装配使用.为使该零件满足使用要求,运用Moldflow试验平台建立有限元模型,选定聚甲醛作为制件材料,选择熔体温度A、保压压力B、保压时间C与冷却时间D作为设计变...     

基于Moldflow的注射器翘曲分析

利用Moldflow软件对注射器塑料件的翘曲原因进行分析,并采用正交试验设计方法(单参数变动实验)对保压压力、熔体温度、模具温度、冷却时间等进行分析。经分析后得出影响制品翘曲变形的最主要因素是保压压力,其次则是熔体温度、模具温度、冷却时间。模拟得到本例最优成型参数分别为,模具温度35℃、熔体温度240℃、保压压力100MPa、保压时间17s、冷却时间20s。     

非球面透镜注射压缩成型工艺优化与透光率分析

采用信噪比法,以非球面透镜的翘曲变形、折射指数变化、体积收缩率为实验目标,注射时间、保压时间、冷却时间、压缩距离、压缩力、压缩时间、压缩延时时间为实验因素,对透镜的注射压缩成型过程采用Moldflow 2015软件进行模拟与透光率测试。结果表明:最优工艺参数组合为A2B2C3D3E2F1G3,经过优化后透镜的最大翘曲变形量为0.0125 mm,透镜折射指数变化和体积收缩率比优化前分别减小63%和39%,优化前透镜的透光率76.3%,优化后透光率81.8%,通过信噪比法对注射压缩成型工艺参数的优化,可以有效提高非球面透镜的成型质量和光学性能。     

基于RBF神经网络断路器注塑成型工艺优化

塑壳断路器一般通过注塑成型工艺制得。在注塑成型过程中，模具温度、熔体温度、保压压力以及保压时间均对制件的翘曲变形产生一定的影响。以模具温度、熔体温度、保压压力以及冷却时间作为研究参数，以翘曲变形量作为研究目标，采用最优拉丁超立方抽样法抽取合适的样本，建立RBF神经网络模型，结合遗传算法对制件的翘曲变形量进行优化，得到最佳的成型工艺参数组合。结果表明：四个因素的影响程度大小为模具温度>冷却时间>保压压力>熔体温度。当模具温度为50℃、熔体温度为250℃、保压压力为60 MPa以及冷却时间为10 s时，制件的翘曲变形量最小为2.307 7 mm，相较未优化前降低1.294 2 mm，制件成型质量得到明显改善。     

车轮装饰盖零件的注射成型模拟

利用Pro／E建立了车轮装饰盖零件的3D模型，并用Moldflow Plastics Insight软件对其进行流动、保压、冷却和翘曲过程模拟。在数值模拟分析的基础上，得到该零件注射成型的可行工艺参数为：充模时间0.30～0.70s、注射压力75～78NPa、锁模力300t、注射速率410cm^3／s、注射温度230℃、模具温度60℃、保压压力62MPa、保压时间10s、冷却时间20～30s。     

基于响应面传动器成型缺陷研究

传动器通过注塑成型工艺制得,其成型质量直接影响传动器的性能。在注塑成型工艺过程中,模具温度、熔体温度、保压压力以及冷却时间等工艺参数对制件的影响较显著,不合理的工艺参数导致制件出现较大的翘曲变形。通过建立响应面模型,以模具温度、熔体温度、保压压力以及冷却时间为响应参数,以制件的翘曲变形量为响应目标,优化一组最佳的成型工艺参数组合。结果表明：四个变量的影响程度分别为：模具温度>保压压力>冷却时间>熔体温度。当模具温度80℃、熔体温度180℃、保压压力90 MPa、冷却时间20 s,制件的翘曲变形量最小为1.955 mm,较未优化的翘曲变形量降低0.427 7 mm,有效地改善了制件的成型质量。     

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.     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

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.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。