Spinning and drawing properties of ultrahigh‐molecular‐weight polyethylene fibers prepared at varying concentrations and temperatures

The concentrations and temperatures of ultrahigh‐molecular‐weight polyethylene (UHMWPE) gel solutions exhibited a significant influence on their rheological and spinning properties. The shear viscosities of UHMWPE solutions increased consistently with increasing concentrations at a constant temperature above 80°C. Tremendously high shear viscosities of UHMWPE gel solutions were found as the temperatures reached 120–140°C, at which their shear viscosity values approached the maximum. The spinnable solutions are those gel solutions with optimum shear viscosities and relatively good homogeneity in nature. Moreover, the gel solution concentrations and spinning temperatures exhibited a significant influence on the drawability and microstructure of the as‐spun fibers. At each spinning temperature, the achievable draw ratios obtained for as‐spun fibers prepared near the optimum concentration are significantly higher than those of as‐spun fibers prepared at other concentrations. The critical draw ratio of the as‐spun fiber prepared at the optimum concentration approached a maximum value, as the spinning temperature reached the optimum value of 150°C. Further investigations indicated that the best orientation of the precursors of shish‐kebab‐like entities, birefringence, crystallinity, thermal and tensile properties were always accompanied with the as‐spun fiber prepared at the optimum concentration and temperature. Similar to those found for the as‐spun fibers, the birefringence and tensile properties of the draw fibers prepared at the optimum condition were always higher than those of drawn fibers prepared at other conditions but stretched to the same draw ratio. Possible mechanisms accounting for these interesting phenomena are proposed.     

Preparation of V doped lanthanum silicate electrolyte ceramics by combustion method and study on conductance mechanism

Vanadium doped La_9.33Si_6−xV_xO_26+0.5x (x = 0.5, 1.0, 1.5) (LSVO) electrolyte powder was prepared by combustion method at 600°C for 5-7 min. The powder was sintered at 1500°C for 3 hours to prepare LSVO ceramics. XPS, IR, XRD, and EIS analysis show that V⁵⁺ doping replaces Si⁴⁺ in [SiO₄] to form [Si(V)O₄] tetrahedron. With the increase in x, the lattice volume increase. When x = 2.0, the LaVO₄ phase was formed, indicating that the limit doping amount of V⁵⁺ replacing Si⁴⁺ is x ≤ 1.5. The conductivity of LSVO increases significantly with the increase in x (x ≤ 1.0), which attributed to the defect reaction caused by V⁵⁺ doping. The addition of the interstitial oxygen Oi* in 6₃ channels and the increase of lattice volume leads to increased conductivity. When x = 1.0, the highest conductivity is 1.46 × 10⁻² S·cm⁻¹ (800°C). The doping enhancement conductivity mechanism is the Interstitial oxygen defect-Lattice volume composite enhancement mechanism.     

水平井产出剖面测井技术在塔河油田的应用

由于水平井中流体的流动相态和施工工艺的复杂性,造成常规的产出剖面测井技术难以适应于水平井,因此水平井产出剖面测井技术是一项技术含量高、研究难度大、生产迫切需求的工作。本文简单介绍了水平井产出剖面测井技术及爬行器施工工艺,应用该技术成功完成了塔河油田TK109H等三口水平井产出剖面测井,并总结了施工经验与存在的问题,为进一步应用该技术评价生产层段产出状况提供帮助。     

"花牛苹果"农产品地理标志保护问题调研

针对地理标志农产品保护中存在的问题开展调研,从完善立法,协调地方政府部门职责利益,解决农产品地理标志管理体制中存在的问题,使地方名优特色农产品真正成长为品牌产品,在农业产业化、标准化、现代化过程中发挥真正的作用,带来和其品牌相适应的经济效益,服务地方经济,服务“三农”。     

厦门海沧保税港区建设思路探析

厦门海沧保税港区的建设,对于厦门港口经济的发展具有巨大的推动作用,而且可进一步加强两岸的经济交流与互动。介绍了我国保税港区的政策功能及厦门海沧保税港区的建设规划,分析了海沧保税港区发展具有的优势、面临的机遇和需要面对的挑战,提出了海沧保税港区的建设措施。     

谈普通高校的音乐教育与素质教育

阐述了音乐教育和素质教育的涵义,指出了音乐教育的本质特征,论述了音乐教育在普通高校素质教育中的作用,并从实践角度提出了高校加强音乐教育的对策和建议.     

祭厉信仰习俗的传承与发展空间

非正常死亡或无子嗣不能享受后人祭祀的鬼魂称之为"厉".在中国古代国家祭祀中,"厉"被列为祭祀对象,历朝沿袭.在民间祭祀中,祭厉信仰习俗一直绵延不绝,现代社会仍在传承与发展.拓展祭"厉"信仰习俗发展空间,既体现了普世人文关怀,又能在一定程度上促进社会和谐.     

伊拉斯莫和平主义思想探析

伊拉斯莫非常关注基督教欧洲的和平,他认为只要拿起武器就意味着丢掉了德性,对战争进行了强烈的谴责,认为所谓的"正义"战争也伴随着邪恶,对"正义"战争也进行了批判,并且为基督教欧洲和平的实现提出了自己的设想.     

汉语和英语的主题显著与主语显著比较

英语属于主语显著语言,汉语属于主题显著语言.从主语在句子中的位置、作用、必要性及词性方面,对比分析了汉语与英语的这种差异.     

建构主文价值取向的幼儿科学教育

建构主义学习理论以全新的知识观、学生观、学习观和教学观为幼儿科学教育提供了重要的理论依据,成为探究式幼儿科学教育的理论基础.建构主义教育价值取向下的幼儿科学教育以培养幼儿科学兴趣为目标,以亲历探究过程为核心,以过程性评价为方法.