PTT机织物结构与服用性能的灰色关联分析

为了更有效地利用PTT纤维,推动PTT新产品的开发,针对几种不同结构的PTT机织物试样,测试了试样的结构参数和织物风格、悬垂风格、折皱回复等服用性能指标,并开展了PTT机织物结构与服用性能的灰色关联分析。研究发现:织物纬向弯曲长度、纬向弯曲刚度、纬向成形性,纬向松弛收缩率都与纬纱线密度相关性最强;织物经向弯曲刚度、经向成形性、经向急弹(缓弹)折皱回复角都与经纱线密度相关性最强;织物经纬向弯曲长度、剪切刚度、悬垂系数都与织物面密度相关性较强。     

芳纶/碳纤维混杂机织复合材料的力学性能研究

分别以芳纶和碳纤维(CF)为经、纬向纱,采用小样织机制备了不同经纬密度的芳纶/CF混杂平纹织物;以环氧树脂为基体,采用真空辅助树脂转移成形方法制备芳纶/CF混杂织物增强复合材料(简称复合材料);分析了复合材料的力学性能。结果表明:在经向纱(简称经纱)、纬向纱(简称纬纱)的纤维种类分别相同时,复合材料的弯曲强度随经向密度增大而增大;以芳纶为经纱时,复合材料的弯曲模量和拉伸模量随着经纱的密度增大而减小,而复合材料的拉伸强度和断裂伸长率随着经纱密度的增大而增大;以CF为经纱时,复合材料的弯曲模量随着经纱密度的增大而增大,且弯曲强度和弯曲模量均高于以芳纶为经纱时的复合材料。     

织物经纬向对硅橡胶制品成型工艺及力学性能的影响

对比涤纶针织布、涤纶网眼布、玻璃纤维布3种织物及其与硅橡胶复合材料的经纬向性能,分析织物经纬向对硅橡胶制品成型工艺和力学性能的影响。结果表明：3种织物的纬向拉断伸长率均大于经向拉断伸长率;织物/硅橡胶复合材料的力学性能主要由织物提供,纬向拉断伸长率大于经向拉断伸长率,在小变形时经向拉伸力大于纬向拉伸力;加入织物的复合材料的收缩率显著降低,纬向收缩率大于经向收缩率;利用涤纶针织布纬向的大变形,可实现异形制品表面织物无搭接成型;利用织物纬向变形可解决玻璃纤维布/硅橡胶制品长度方向易弯折的问题;增加织物后中空P形结构硅橡胶制品的经向压缩力大于纬向压缩力。在硅橡胶制品结构、模具和工艺设计时,为保证制品的质量一致性,应充分考虑织物经纬向。     

制备工艺对亚麻增强热塑性复合材料拉伸力学性能的影响

将增强体亚麻纱线和基体丙纶复丝制成pp/亚麻包覆纱后,进行织造,织物用层合热压法制成复合材料.制备工艺中,包覆纱法对复合材料的拉伸强度最好;麻含量50%的复合材料的拉伸强度达到最佳;当纬纱密度相同时,随着经纱密度的增大经向的拉伸强力和拉伸弹性模量也随之增大,而纬向的却随之减小,当经纱密度相同时,随着纬纱密度的增大,经向的拉伸强力和拉伸弹性模量随之减小,纬向的随之增大.     

整体中空夹层复合材料平压性能的实验

选取了不同织造参数和基体材料的试验件进行了平压试验,观察描述了平压试验中试验件的破坏过程,并将得到的实验数据进行整理分析。讨论了厚度、绒经密度、基体材料以及绒经粗细对于整体中空夹层复合材料平压性能的影响。发现随着厚度的增加,绒经密度的减小,材料的平压强度减小;基体材料不同,材料的平压强度也明显不同;绒经的粗细对平压性能影响显著。     

混杂比对交织芳纶碳纤维复合材料力学性能的影响

为了分析混杂比对层内混杂复合材料力学性能的影响,利用交织方式制备芳纶碳纤维混杂增强体织物,并通过交织物纬纱系统中芳纶与碳纤维的纱线配置比例调整碳纤维在增强体结构中的混杂比。采用真空辅助成型技术制备层内混杂结构的芳纶碳纤维混杂（ACFH）复合材料,并对复合材料的拉伸性能、弯曲性能和冲击性能进行测试。结果表明,增强体纬向系统中芳纶与碳纤维的不均质性对ACFC复合材料经方向上的拉伸强度起消极作用;混杂比的增加对ACFC复合材料的纬向拉伸破坏和弯曲损伤具有抑制作用;纬向上,ACFC复合材料的拉伸强度最高提高了近6倍,弯曲强度最小增加了4.04倍;芳纶与碳纤维混杂协同作用有利于ACFC复合材料的抗冲击性能改善,且混杂比存在最佳值。     

改性芳纶纬编增强体复合材料力学性能的研究

为探讨芳纶纬编增强体复合材料的力学性能,以对位芳纶为原料,采用LiCl/无水乙醇溶液对芳纶表面进行改性处理,设计并编织1+1满针罗纹和罗纹空气层2种组织织物增强体,以E-51环氧树脂为基体,应用手糊成型技术制备芳纶纬编增强体平板复合材料。采用YG026D型电子织物强力机对制备的芳纶纬编增强体复合平板材料的经纬向拉伸、弯曲、压缩以及层间剪切性能进行测定。结果显示:经LiCl/无水乙醇络合溶液处理的芳纶纬编增强体复合材料的各项力学性能均有所提高,且经向的各项力学性能优于纬向。在拉伸、弯曲性能方面,罗纹空气层芳纶纬编增强体平板复合材料优于1+1满针罗纹芳纶纬编增强体复合材料。     

制备工艺对亚麻增强聚丙烯复合材料拉伸性能的影响

以亚麻纤维为增强体,与聚丙烯（PP）长丝进行丝束级共混,形成PP包覆亚麻的纱线结构,利用机织工艺织成二维机织布,作为复合材料的预制件。采用层合热压方法制备PP／亚麻复合材料板材。通过对板材拉伸性能测试及扫描电镜（SEM）拉伸断口形貌分析,研究了不同纤维体积分数、织造密度及织造组织等因素对复合材料拉伸性能的影响。结果表明,在选取最优热压温度与压力的条件下,纤维体积分数为50％的板材性能最优;经向密度相同时,拉伸性能随着纬向密度的增加而提高;经、纬向密度均相同时,斜纹3／1组织的板材性能最优,纬向最大拉伸强度可达92．42 MPa。     

铝蒙皮整体中空夹层复合材料低速冲击的实验研究

本文采用落锤冲击试验机对铝蒙皮整体中空夹层复合材料进行了低速冲击试验.利用加速度传感器记录落锤冲击过程中加速度随时间变化曲线,通过数学处理得到了冲击栽荷、冲击点位移、材料损伤吸收能量随时间的变化曲线.探讨了铝蒙皮对整体中空夹层复合材料的低速冲击特性,如最大冲击载荷、冲击点最大位移和材料损伤时能量吸收等的影响.结果表明,附加铝蒙皮后,整体中空夹层复合材料的接触刚度、最大冲击栽荷以及材料的初始损伤能量都有明显增加.     

等离子体处理对芳纶针织物复合材料性能的影响

将芳纶织成纬平针织物,再进行等离子体处理;将未处理及处理的芳纶纬平针织物与E44环氧树脂复合制成芳纶针织物复合材料,测试了复合材料的抗拉强度和抗压强度,结果显示:相比处理前,经等离子体处理过的复合材料的经向抗拉强度和纬向抗拉强度分别提高了49%和33%;经向抗压强度和纬向抗压强度分别提高了40%和39%;经向的抗拉强度和抗压强度均大于纬向的。     

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.     

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.     

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。     

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.