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航天用吸波材料的制备及研究进展 总被引:1,自引:0,他引:1
简述了吸波材料的研究意义,综述了涂覆型吸波材料的研究现状和应用进展,重点介绍了单层电磁损耗型、多层介质匹配吸收型、干涉(谐振)型、电路模拟型、等离子体吸收型、手征型、导电高聚物型、泡沫夹芯型、贴片型和表面波吸波材料的主要特点和最新研究现状,最后对涂覆型吸波材料的发展趋势进行了展望。 相似文献
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陈君华 彭开美 丁秋莉 王锋 胡剑青 涂伟萍 CHEN Jun-hua PENG Kai-mei DING Qiu-li WANG Feng HU Jian-qing TU Wei-ping 《电镀与涂饰》2019,38(8)
介绍了阴极电泳涂料的发展历程与原理。总结了近年来在环保型、低温型、紫外光固化型、薄层型、厚膜型、单组分型、自分层型、耐热型、高装饰型等方向上的最新研究成果。 相似文献
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介绍了脱酰胺、脱羟胺型单组分室温硫化(RTV-1)硅橡胶的特点,以及脱酰胺/羟胺型(包括普通型、高粘接性型、耐水性型、超低模量型)、脱羟胺型(包括用含S-H基的硅氧烷或异氰酸酯作羟胺清除剂)、脱酰胺型(快干型、自流平型)及脱酰胺/酮肟型低模量RTV-1硅橡胶的配制。 相似文献
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本研究为浅水型湖泊“黑水团”暴发后的应急复氧研制出三套升流循环复氧装置。三种装置均采用气弹释放循环复氧流复氧,分别为Ⅰ封闭曝气型、Ⅱ敞口曝气型、Ⅲ敞填料曝气型装置。小试结果显示Klas指标Ⅲ型比Ⅰ型、Ⅱ型分别高出179%、51%;Qc指标Ⅲ型比Ⅰ型、Ⅱ型分别高出167%、50%;ε指标Ⅲ型比Ⅰ型、Ⅱ型分别高出176%、51%;Ⅲ型装置功率因子E比Ⅰ型、Ⅱ型分别高出29%、50%。中试于太湖边沉藻池中采用模拟“黑水团”的沉藻池水进行实验,中试型Ⅲ型多面球形填料装置可使水深1.8 m,面积200 m2模拟黑臭水体边缘溶氧28 h内恢复到1.69 mg·L-1,供氧效率达到26%,并对水中CODCr、氨氮等的降解具有良好的作用。该设备初步证明可用于类似太湖黑臭团暴发时水体的应急治理领域。 相似文献
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介绍了UV-P的合成方法,即:将2-硝基苯胺(1)用亚硝酸钠(2)和盐酸重氮化后与4-甲基苯酚(3)进行偶合反应制成2-硝基-2′-羟基-5′-甲基偶氮苯(4)。(1)、(2)、(3)的摩尔比为1:1.05:1。将(4)用水合肼还原为2-(2′-羟基-5′-甲基苯基)苯并三唑N-氧化物(5),然后再用锌粉还原(5)为2-(2′-羟基-5′-甲基苯基)苯并三唑(UV-P)。该类产品与受阻胺光稳定剂(HALS)并用于PP、PE、PVC、PS时,有协同效应,效果随材料不同而异。 相似文献
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聚合物基阻尼材料研究进展 总被引:1,自引:0,他引:1
介绍了4种类型的聚合物基阻尼材料,即黏弹型、导电压电型、有机小分子杂化型和无机小分子杂化型。探讨了聚合物基阻尼材料的组成、配方、阻尼性能及其原理。 相似文献
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淀粉基木材胶黏剂研究现状与展望 总被引:4,自引:0,他引:4
利用廉价的淀粉开发高性能的木材胶黏剂是人类永久的梦.但是传统的淀粉胶黏剂不能用于木材的黏结.早期的淀粉基木材胶黏剂研究是将淀粉在强烈的反应条件下转化为低分子物质来充当酚醛胶的填料.而目前的发展趋势是既要考虑充分利用淀粉的大分子特性,避免过度降解,又要能够向淀粉链中引入足够的均匀分布的化学键,使其与氢键的弱化学作用力有效配合,达到木材胶黏剂耐水的要求.双醛淀粉树脂胶;淀粉、聚乙烯醇和六甲氧甲基三聚氰胺共混胶;淀粉氧化降解接枝改性聚氨酯型胶等都是这类努力的代表性工作.我们的研究结果表明,淀粉经常压快速液化可以制备高活性的多羟基化合物.利用淀粉基多羟基化合物与多元酸(酐)聚合成功地制备了新型聚酯型的木材胶黏剂,成本与酚醛树脂相当,但其施胶量仅为酚醛树脂的1/3~1/2,可以用于高耐水性胶合板的生产. 相似文献
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Silicon Nitride Based Ceramic Nanocomposites 总被引:7,自引:0,他引:7
Xiaoqing Pan Joachim Mayer Manfred Rühle Koichi Niihara 《Journal of the American Ceramic Society》1996,79(3):585-590
Nanocomposites (Si3 N4 /SiC) were studied by combined high-resolution transmission electron microscopy and electron energy-loss spectroscopic imaging (ESI) techniques. In ESI micrographs three types of crystalline grains were distinguished: Si3 N4 matrix grains (0.5 μΩ), nanosized SiC particles (<100 nm) embedded in the Si3 N4 , and large SiC particles (100–200 nm) at grain boundary regions (intergranular particles). Amorphous films were found both at Si3 N4 grain boundaries and at phase boundaries between Si3 N4 and SiC. The Si3 N4 grain boundary film thickness varied from 1 to 2. 5 nm. Two kinds of embedded SiC particles were observed: type A has a special orientation with respect to the matrix, and type B possesses a random orientation with respect to the matrix. The surfaces of type B particles are completely covered by an amorphous phase. The existence of the amorphous film between the matrix and the particles of type A depends on the lattice mismatch across the interface. The mechanisms of nucleation and growth of Ω-Si3 N4 grains are discussed on the basis of these experimental results. 相似文献
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The minimum fluidization velocities of sand, ilmenite, limestone and quartz magnetite were determined at temperatures ranging from 373–973 K. A best fit of the Wen and Yu type of equation was obtained for the experimental data. This correlation was extended to all experimental data obtained by various workers at high temperatures and was also compared with the existing correlations. However, a very high error percentage was obtained (> 50 %). The Geldart Powder Classification was made use of in classifying all materials used by different workers, as A, B and D, based on the material properties i.e., density and particle size. According to Geldart, C type powders are highly cohesive and hence cannot be subject to normal fluidization. Separate correlations were fitted for A, B and D type powders. Fitting separate correlations reduced the error by a considerable amount. Thus, the usage of separate correlations to predict the minimum fluidization velocity for A, B and D type powders was substantiated. 相似文献
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