层叠顺序对UHMWPE-铝合金板抗冲击性能影响

为探究层叠顺序对双硬度UHMWPE-铝合金板抗冲击性能影响,以高分子聚乙烯(UHMWPE)板、7075高强铝合金板为对象,利用一级轻气炮开展一系列平头和卵形弹打靶试验,对靶板弹道极限速度、能量吸收率、破坏模式等进行分析.揭示板材层叠顺序对接触式高分子聚乙烯-铝合金靶板防护性能的影响规律.结果表明:平头弹撞击下,UHMWPE板在前铝合金板在后的叠放顺序("软+硬")防护性能更高;卵形弹撞击下,两种叠放顺序靶板防护性能相近;两种叠放顺序靶板在平头弹撞击下均发生"冲塞破坏",在卵形弹冲击下均发生"延性扩孔"破坏.     

Fabrication of direct Z-scheme FeIn2S4/Bi2WO6 hierarchical heterostructures with enhanced photocatalytic activity for tetracycline hydrochloride photodagradation

A series of direct Z-scheme FeIn₂S₄/Bi₂WO₆ hierarchical heterostructures with intimate interface contacts were synthesized by in-situ growth route and characterized by systematical analyses. All as-prepared FeIn₂S₄/Bi₂WO₆ nanocomposites showed significantly enhanced photocatalytic activity towards photodegradation for the removal of tetracycline hydrochloride (TCH) in comparison with individual FeIn₂S₄ and Bi₂WO₆. Meanwhile, the highest photocatalytic degradation activity can be achieved by modulating adding amount of FeIn₂S₄ in FeIn₂S₄/Bi₂WO₆ nanocomposites and the optimized component ratio of FeIn₂S₄ to Bi₂WO₆ is determined to be 10 wt%. The enhanced photocatalytic activity could be ascribed to efficient separation between photogenerated holes and electrons based on the construction of direct Z-scheme system. The high photocatalytic stability of resultant 10 wt% FeIn₂S₄/Bi₂WO₆ nanocomposites was revealed through six successive recycling reactions. The main intermediate generated during TCH photodegradation was explored by HPLC-MS. Besides, the direct Z-scheme photocatalytic mechanism was confirmed by band position analysis, electron spin resonance (ESR) and active species capture experiment.     

Mixed coordination mechanisms for scheduling games on hierarchical machines

In this paper, we study scheduling games under mixed coordination mechanisms on hierarchical machines. The two scheduling policies involved are ‐ and ‐, where ‐ (resp., ‐) policy sequences jobs in nondecreasing order of their hierarchies, and jobs of the same hierarchy in nonincreasing (resp., nondecreasing) order of their processing times. We first show the existence of a Nash equilibrium. Then we present the price of anarchy and the price of stability for the games with social costs of minimizing the makespan and maximizing the minimum machine load. All the bounds given in this paper are tight.     

深孔薄壁件挤压模CAD系统

介绍了利用ActiveXAutomation技术，以VB为开发工具，并采用参数化绘图研究开发的深孔薄壁件挤压模CAD系统。     

Design consideration of photocatalytic oxidation reactors using TiO2-coated foam nickels for degrading indoor gaseous formaldehyde

In the design process of the photocatalytic oxidation (PCO) reactor using TiO₂-coated foam nickels, the optimum of catalyst film thickness, light intensity and flow velocity were considered. A model was developed to study the effect of catalyst film thickness on photocatalytic degradation of formaldehyde by a TiO₂-coated foam nickel at continuous flow mode. In this model, external mass transfer and internal molecule diffusion-reaction were considered. A first-order kinetics equation was used to account for the photocatalytic reaction. Two exponential equations were employed to describe the distribution of light intensities in foam nickels and catalyst films, respectively. Validated with experimental data, the model can be used to predict the optimal thickness of catalyst films. A method for determining appropriate light intensities was proposed and discussed. The appropriate light intensity can be obtained by giving a margin, regarded as an excess coefficient, to the light intensity calculated based on the assumption of complete use of excited electron–hole pairs. The excess coefficient needs to be determined experimentally. In addition, the optimal flow velocity of PCO reactors could be consistent with the required one by changing the windward area of foam nickels. Based on the theoretical analyses, a novel PCO reactor containing 15 parallel-connected cells was designed. Each reaction cell was composed of an UV lamp and a TiO₂-coated tubular foam nickel. The performance of the reactor was tested by degrading gaseous formaldehyde at an indoor concentration level. The results showed that the reactor had low pressure loss and good degradation capability.     

蒙脱土-有机硅复合改性硅烷化聚氨酯密封胶

采用2,4-甲苯二异氰酸酯、聚醚多元醇、蒙脱土、有机硅(α,ω-二羟基聚二甲基硅氧烷)和硅烷偶联剂为原料,制备了有机蒙脱土/聚醚多元醇复合物(OMMT/330N)-有机硅复合改性的硅烷化聚氨酯(SPU)密封胶。通过广角X射线衍射、透射电子显微镜和傅里叶变换红外光谱手段表征了蒙脱土在复合材料中的分散情况,表征结果显示,有机蒙脱土以平均层间距不小于4.12nm的宽分布分散在SPU基体中。同时对密封胶的力学性能进行测试,测试结果表明,经OMMT/330N-有机硅复合改性的SPU密封胶具有性能互补效果,当添加质量分数为5%(基于330N)的OMMT和8%的有机硅时,复合改性的SPU密封胶的拉伸强度和断裂伸长率比纯SPU密封胶提高了65.8%和71.6%。     

Evaluating Visual Properties via Robust HodgeRank

International Journal of Computer Vision - Nowadays, how to effectively evaluate visual properties has become a popular topic for fine-grained visual comprehension. In this paper we study the...     

陶瓷纳米颗粒在生物医学中的应用进展

近年来,纳米技术成为科学技术领域最重要与最激动人心的前沿领域之一.随着纳米技术的发展,纳米材料在生产和生活的各方面发挥着越来越重要的作用.陶瓷纳米颗粒作为一类重要的纳米材料,拥有体积效应、介电限域效应、量子尺寸效应和量子隧道效应等,使其在生物医学领域具有广阔的应用前景.本文综述了羟基磷灰石、磷酸钙、氧化铁、氧化锌和氧化铈陶瓷纳米颗粒的特点及其在肿瘤成像与治疗、骨组织工程和安全评价等生物医学领域的应用进展,并对陶瓷纳米颗粒在生物医学中的发展提出了几点建议.