EBA改性对聚碳酸酯增韧性能的影响

采用乙烯-丙烯酸丁酯共聚物（EBA）对高抗冲聚碳酸酯（PC）进行增韧改性。分别使用缺口冲击试验机、万能试验机、熔融指数仪和FESEM对PC和EBA增韧的PC的力学性能,流动性和结构形态进行表征。结果表明：随着EBA含量的增加,材料的韧性逐渐增强,10％的EBA增韧PC时,增韧效果较好,冲击强度达81kJ／m2,但共混材料的熔融指数降低到11．5g／10min。因此,在注射成型过程中应适当提高注射成型温度和压力;当EBA用量超过10％时,增韧PC的拉伸强度、弯曲强度有明显下降。     

液态模锻6061铝合金轮毂组织及性能

采用液态模锻成型时,为了研究铝合金轮毂不同部位的微观组织和力学性能,利用金相显微镜和拉伸试验机对液态模锻6061铝合金轮毂不同部位的组织及性能进行了研究.结果表明:外轮缘处晶粒最细小,而轮辐部位的晶粒最粗大;外轮缘的抗拉强度和伸长率最高,可以分别达到371 MPa和16%,轮辐部位的抗拉强度强度和伸长率最低,分别为346 MPa和9%.轮辋处的合金晶粒大小不一,且部分晶粒被拉长变形,这是由于该处糊状金属流动产生的冲刷和挤压所致.     

Modern interpretation on the high-stretching of natural rubber attained by the classic ‘racking’ method

To investigate the mechanism of high elongation of natural rubber attained by the ‘racking method’, a strip of smoked-sheet was elongated up to 150 times in length, by stretching rapidly at room temperature and forcing to shrink at 75-80 °C repeatedly. On X-ray diffraction, a typical fibre pattern with an amorphous ring appeared already at ×10 (stretch ratio=10). The degree of crystallinity increased to the level of 17-18% at ×20 and turned to decrease after ×60, but the degree of crystallite orientation reached at a high level already at ×10 and did not change significantly and the half-height width of reflection profiles stayed almost at a constant level, while the Young's modulus increased up to ca. 300 MPa at ×100 and then fell rather discontinuously. It was assumed that some fractions of chain segments between entanglements were gradually broken in each step of stretching operation, rather than disentangled and slipped.     

高伸长异形涤纶FDY工艺

介绍用纺丝拉伸一步法纺制73dtex/24f高伸长三叶异形涤纶全拉伸丝的生产工艺。通过计算设计出可用的喷丝孔径,并摸索出适宜的组件组装工艺,纺丝温度,纺丝冷却成型条件、预网络条件、拉伸工艺、卷绕张力。     

高强度高伸长率聚氨酯改性不饱和聚酯

利用聚氨酯改性的方法合成了一种新型不饱和聚酯，该树脂可以室温固化，固化后拉伸强度达20MPa、断裂伸长率高达100％以上，可用于制作柔韧性要求较高的制品，亦可以加入其它树脂中，提高材料的冲击性能和断裂伸长率。     

聚苯硫醚/聚四氟乙烯复合材料的研究

制备并研究了PPS/PTFE合金的热行为、力学性能以及摩擦学性能,并对其微观形态进行了观察。实验结果表明,此合金的耐热性能相对于聚苯硫醚纯树脂有明显的提高,而且聚四氟乙烯的加入可以改善聚苯硫醚的力学性能及摩擦磨损性能。     

Magnetic-field amplification in metal shaped-charge jets during their inertial elongation

This paper considers magnetic-field amplification in inertially elongating metal shaped-charge jets formed by explosion of a shaped charge with an axial field previously produced in the charge liner. The amplification is related to the effect of magnetic-field freezing in a conducting material and is due to the deformation of the jet material with particle elongation along the magnetic lines. The model of a uniformly elongating, conducting, incompressible, cylindrical rod was used to determine the nature of the field variation in the jet elements versus the magnetic Reynolds number determined by the electrical resistance of the material, the initial axial-strain rate, and the element radius. In high-gradient copper shaped-charge jets, the magnetic field can be amplified by more than a factor of five during elongation. It is shown that the joint action of the force and thermal factors accompanying field amplification in the jet material can lead to jet breakup with radial scattering of the material particles.Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 1, pp. 120–128, January–February, 2005.     

High eEF1A1 Protein Levels Mark Aggressive Prostate Cancers and the In Vitro Targeting of eEF1A1 Reveals the eEF1A1–actin Complex as a New Potential Target for Therapy

Although the eukaryotic elongation factor eEF1A1 plays a role in various tumours, there is little information on its prognosis/therapeutic value in prostate carcinoma. In high-grade and castration-resistant prostate carcinoma (CRPC), the identification of novel therapeutic markers/targets remains a priority. The expression of eEF1A1 protein was determined in formalin-fixed, paraffin-embedded prostate cancer and hyperplasia tissue by IHC. The role of eEF1A1 was investigated in a cellular model using a DNA aptamer (GT75) we previously developed. We used the aggressive CRPC cancer PC-3 and non-tumourigenic PZHPV-7 lines. Cytotoxicity was measured by the MTS assay and eEF1A1 protein levels by in-cell Western assays. The mRNA levels of eEF1A1 were measured by qPCR and ddPCR. Higher expression of eEF1A1 was found in Gleason 7–8 compared with 4–6 tissues (Gleason ≥ 7, 87% versus Gleason ≤ 6, 54%; p = 0.033). Patients with a high expression of eEF1A1 had a worse clinical outcome. In PC-3, but not in PZHPV-7, GT75 decreased cell viability and increased autophagy and cell detachment. In PC-3 cells, but not in PZHPV-7, GT75 mainly co-localised with the fraction of eEF1A1 bound to actin. Overexpression of the eEF1A1 protein can identify aggressive forms of prostate cancer. The targeting of eEF1A1 by GT75 impaired cell viability in PC-3 cancer cells but not in PZHPV-7 non-tumourigenic cells, indicating a specific role for the protein in cancer survival. The eEF1A1–actin complexes appear to be critical for the viability of PC-3 cancer cells, suggesting that eEF1A1 may be an attractive target for therapeutic strategies in advanced forms of prostate cancer.     

高拉伸强度高伸长率丁羟弹性体的研究进展

综述了影响丁羟弹性体力学性能的几种关键因素,包括固化参数、固化剂类型、扩链剂类型等,对比了几种提高丁羟弹性体力学性能的方法及其研究进展。提出了通过合成具有不同官能度的窄分子质量分布的丁羟液体橡胶,并进行复配研究,将是制备高拉仲强度、高伸长率丁羟弹性体的研究方向。     

新型双马来酰亚胺改性氰酸酯树脂及其复合材料

采用双马来酰亚胺封端的硫醚酰亚胺低聚物对氰酸酯树脂进行了改性(SBMI),通过红外光谱对改性树脂(SBT)的结构作了表征,通过流变分析,热失重分析研究了其粘度特性及耐热性,并对其玻纤复合材料的力学性能进行了测试。结果表明,当SBMI质量分数为氰酸酯树脂的的37.5%时,SBT树脂的5%热失重温度为415℃,其复合材料在常温下的拉伸强度为438.8 MPa,弯曲强度为657.3 MPa,断裂伸长率为9.2%;200℃时拉伸强度为310.5 MPa,弯曲强度为307.4 MPa,断裂伸长率为12.5%。该树脂具有良好的加工性,耐热性和力学性能。