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81.
H4PMo11Vo40杂多酸及其镧盐的合成与性质   总被引:3,自引:0,他引:3  
本文提出主要用~(51)V NMR、CV并辅以IR、XRD、DTG、元素分析等作为有效地核查纯度和表征催化剂的手段。  相似文献   
82.
冲击伤复合高速破片致伤的损伤特点和冲击伤防护研究   总被引:17,自引:0,他引:17  
探讨了冲击伤复合高速破片致伤的损伤特点及复合材料对冲击伤的防护效果。结果表明,肢体高速破片致伤对肺冲击伤具有加重作用,加重效应主要发生在原发冲击伤部位,加重效应的机理可能与压力波引起的血流扰动有关。利用复合材料防护可减轻肺冲击伤程度,降低动物的死亡率。  相似文献   
83.
The biosynthesis of tryptophan tryptophylquinone, a protein‐derived cofactor, involves a long‐range reaction mediated by a bis‐FeIV intermediate of a diheme enzyme, MauG. Recently, a unique charge‐resonance (CR) phenomenon was discovered in this intermediate, and a biological, long‐distance CR model was proposed. This model suggests that the chemical nature of the bis‐FeIV species is not as simple as it appears; rather, it is composed of a collection of resonance structures in a dynamic equilibrium. Here, we experimentally evaluated the proposed CR model by introducing small molecules to, and measuring the temperature dependence of, bis‐FeIV MauG. Spectroscopic evidence was presented to demonstrate that the selected compounds increase the decay rate of the bis‐FeIV species by disrupting the equilibrium of the resonance structures that constitutes the proposed CR model. The results support this new CR model and bring a fresh concept to the classical CR theory.  相似文献   
84.
The surface chemical modified aluminum hypophosphite (AHP) defined as MAHP was successful prepared through P–H bonds on AHP surface reacted with the aldehyde groups in hexa‐(4‐aldehyde‐phenoxy)‐cyclotriphosphazene made in our lab. The wettability of the flame retardants was evaluated by water contact angle tests, and the water contact angle of the prepared MAHP dramatically increased from 0° for AHP to 145°, which indicated the surface modification made the superhydrophilic AHP into superior hydrophobic MAHP. The prepared MAHP and AHP, respectively, incorporated into polyamide 6 (PA6) matrix to prepare flame retardant PA6 composites and the fire retardancy and thermal degradation behavior of flame retardant PA6 composites were investigated by limiting oxygen index, vertical burning test (UL‐94), cone calorimeter, and thermogravimetric analysis tests. The morphologies and chemical compositions of the char residues for PA6 composites were investigated by scanning electron microscopy and X‐ray photoelectron spectroscopy, respectively. The water resistant properties of flame retardant PA6 composites were evaluated by putting the samples into distilled water at 70°C for 168 hr, and the mechanical properties for flame retardant PA6 composites were investigated by the tensile, flexural, and Izod impact strength tests. The results demonstrated that the PA6/MAHP composites successfully passed UL‐94 V‐0 flammability rating, and the limiting oxygen index value was 27.6% when the loading amount of MAHP was 21 wt%. However, there is no rating in vertical burning tests for PA6/AHP composite with the same amount of AHP, which indicated the surface modification of AHP enhanced the flame retardancy efficiency for PA6 composites. The morphological structures and analysis of X‐ray photoelectron spectroscopy of char residues revealed that the surface modification of AHP benefited to the formation of a sufficient, flame retardant elements rich, more compact and homogeneous char layer on the materials surface during combustion, which prevented the heat transmission and diffusion, limit the production of combustible gases, inhibit the emission of smoke and then led to the reduction of the heat release rate and smoke produce rate. The mechanical properties results revealed that the surface modification of AHP enhanced the mechanical properties, especially the Izod impact strength comparing with that of PA6/AHP composites with the same amount of flame retardant. After water resistance tests, the PA6/MAHP composites remained superior flame retardancy and presented continuous and compact char layer after cone calorimeter tests; however, the fire retardancy for PA6/AHP composite obviously decreased, and the char layer was discontinuous with big hole caused by the extraction of AHP by water during water resistance tests. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   
85.
Petty's conjectured projection inequality is a famous open problem in the theory of convex bodies. In this paper, it is shown that an inequality relating to Lp-version of the Petty's conjectured projection inequality is developed by using the notions of the Lp-mixed volume and the Lp-dual mixed volume, the relation of the Lp-projection body and the geometric body Г-pK, the Bourgain-Milman inequality and the Lp-Bnsemann-Petty inequality. In addition, for each origin-symmetric convex body, by applying the Jensen inequality and the monotonicity of the geometric body Г-pK, the reverses of Lp-version of the Petty's conjectured projection inequality and the Lp-Petty projection inequality are given, respectively.  相似文献   
86.
光纤传感器对机敏复合材料结构性能的影响   总被引:13,自引:0,他引:13  
冷劲松  王殿富 《实验力学》1995,10(4):309-315
本文通过实验研究了光纤传感器对埋光纤机敏复合材料机械性能的影响,详细分析了埋光纤机敏复合材料层板在外载作用下的应力分布,针对三种不同铺层方式,研究了六种树脂填充区对机敏复合材料层板应力集中的影响,得出了减小应力集中的有效方案。  相似文献   
87.
冷春玲  张英俏  计新 《物理学报》2015,64(18):184207-184207
提出了利用在一维传输线共振器中的破坏对称性的超导人造原子来制备χ型四比特纠缠态的方案. 方案中所用到的Δ型三能级人造原子不同于自然的原子, 它可以产生循环跃迁. 经过适当时间的相互作用和简单的操作, 可以得到想要制备的纠缠态. 由于人造原子的激发态和光子态被绝热消除, 所以该方案对于人造原子的自发辐射和传输线共振器的衰减是鲁棒的.  相似文献   
88.
组合催化剂上丙烷选择氧化制丙烯酸   总被引:1,自引:0,他引:1  
方雯  葛庆杰  俞佳枫  徐恒泳 《催化学报》2011,32(6):1022-1026
考察了在C3H8氧化脱氢的NiZrO催化剂和C3H6选择氧化的Mo基催化剂组成的组合催化剂上C3H8选择氧化制取丙烯酸的反应性能.结果表明,两个催化剂比例适当时,反应的丙烯酸收率可达最大.优化温度、烷氧比、空速以及N2含量等反应条件的结果发现,反应体系中O2的匮乏会严重影响反应性能.在有氧分布器的反应装置中对所选组合催化剂在优化的反应条件下进行了30h稳定性测试,结果表明,在340oC,反应性能基本稳定,C3H8转化率和丙烯酸选择性可分别维持在~20%和~74%.  相似文献   
89.
采用CO和H2脉冲吸附、程序升温还原、NH3程序升温脱附及X射线衍射等手段对各金属氧化物改性的Pt/Al2O3催化剂进行了表征,研究了助剂形态对Pt/Al2O3催化剂在非临氢条件下催化环己烷脱氢反应性能的影响.结果表明,催化剂稳定性从高到低依次为Zr-Pt/Al2O3> Ca-Pt/Al2O3> Ce-Pt/Al2O3...  相似文献   
90.
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