吸波材料的物理机制及其设计

吸波材料是一种重要的军事隐身功能材料,其机理本质上是电磁波与物质相互作用,入射的电磁波通过介质最大限度地转变成熟能或其他形式的能。评价吸波效能的主要参数是损耗因子、复介电常数、复磁导率。作者用简单的等效电路分析了材料吸波机制,阐明了这些参数的物理意义,定性地给出了吸波材料的设计方向。分析结果表明：吸波材料的电磁损耗机制分为3种类型,即电阻损耗型、介电损耗型和磁损耗型;设计吸波材料时要综合考虑损耗吸收和波阻匹配2种因素;多元复合尤其是纳米无机物与有机聚合物复合,将3种损耗有效结合,并尽可能阻抗匹配,这是实现轻质、强吸收、宽频、微波红外隐身兼容且综合性能好的吸波材料的有效途径;研究材料的吸波特性还必须从微观层次上用量子理论分析材料对电磁波的基本吸收过程。     

Synthesis and tribological properties of antimony N, N-diethanoldithiocarbamate

1　ＩＮＴＲＯＤＵＣＴＩＯＮＡｎｔｉｍｏｎｙｏｒｇａｎｉｃｃｏｍｐｏｕｎｄｈａｖｅｂｅｅｎｗｉｄｅｌｙｕｓｅｄａｓｈｅａｔｓｔａｂｉｌｉｚｅｒ ,ｆｉｒｅｒｅｔａｒｄａｎｔ ,ｃａｔａｌｙｚｅｒ ,ａｎｄｍｅｄｉｃｉｎｅａｂｒｏａｄ[1～ 5] .Ｉｎｏｕｒｃｏｕｎｔｒｙｔｈｅｓｔｕｄｙｏｆａｎ ｔｉｍｏｎｙｏｒｇａｎｉｃｃｏｍｐｏｕｎｄｗａｓｓｅｌｄｏｍｃａｒｒｉｅｄｏｕｔａｌ ｔｈｏｕｇｈｔｈｅｒｅａｒｅｐｌｅｎｔｉｆｕｌａｎｔｉｍｏｎｙｒｅｓｏｕｒｃｅｓ .Ｈｅｒｅｔｈｅｈｅａｔｓｔａｂｉｌｉｔｙｐｒｏｐｅ…     

稀土在汽车尾气三效净化催化剂中应用的研究

稀土元素以其特殊的电子结构和性能在汽车尾气三效净化催化剂（TWC）中获得了广泛应用,它在TWC中用作助催化剂,稳定剂,贵金属和载体的表面分散剂及钙钛矿稀土复合催化剂等。     

组合化学在无机功能材料中的研究进展

综述了近些年来,组合化学产业的历史背景、条件、基本方法、基本理论、以及在无机功能材料中的研究进展。     

Cerium-zinc redox flow battery: Positive half-cell electrolyte studies

Experimental work was performed to evaluate the Ce3+/Ce4+ redox couple in methane sulfonic acid (MSA) electrolyte for use in redox flow battery (RFB) technology. The electrochemical behaviour of the Ce3+/Ce4+ in MSA media was investigated using cyclic voltammetry, linear sweep voltammetry, chronoamperometry and rotating disc electrode. The standard rate constant of the Ce3+/Ce4+ redox reaction on graphite electrode in MSA was 4.06×10-4 cm/s. The diffusion coefficient of Ce3+ in MSA was 5.87-6.15×10?6 cm2/s, and was 2.56-2.68×10?6 cm2/s for Ce4+. The energy efficiency of a cerium-zinc test cell was 74.8%. The high stability of cerium salts in MSA media and relatively fast redox kinetics of the Ce3+/Ce4+ redox reaction at graphite ectrode indicated that the Ce3+/Ce4+ might be well suited for use in RFB technology.     

Electrochemical behavior of diverse vanadium ions at modified graphite felt electrode in sulphuric solution

PAN-based graphite felt (PGF) treated in 98% sulphuric acid for 5 h and then kept at 450 ℃ for 2 h was evaluated for their electrochemical performance as electrodes of vanadium redox battery (VRB). Structure and characteristic of treated PAN-based graphite felt (TPGF) were determined by means of Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Brunauer-Emmett-Teller surface area analysis and VRB test system. The results show that the acid and heat synergistic effect increase the number of —COOH functional groups on the PGF surface, and the PGF is eroded by sulphuric acid oxidation, resulting in the surface area increases from 0.31 m2/g to 0.45 m2/g. The V(Ⅱ)/V(Ⅲ) redox reaction is electrochemically reversible on the TPGF electrode, while the V(Ⅳ)/V(Ⅴ) couple is a quasi reversible process. The diffusion coefficients of the oxidation for V(Ⅳ)/V(Ⅴ) obtained from the scope of peak current Ip vs scan rate v1/2 is 4.4×10-5 cm2/s. The improvement of electrochemical activity for the electrode is mainly ascribed to the increase of the number of —COOH groups on the TPGF, which behaves as active sites catalyzing the vanadium species reactions and accelerating electron transfer reaction and oxygen transfer.     

PP/SEBS基导电复合材料的研制

以聚丙烯(PP)和(苯乙烯/乙烯/丁烯/苯乙烯)共聚物(SEBS)的共混物为基体材料,通过掺杂炭黑和碳纤 维,用开炼法制备了一种高电导率的导电复合材料,其体积电阻率小于0.1Ω·cm,并作为集流体材料应用于全钒氧 化还原液流电池。     

韶关冶炼厂硫酸系统的技术改造

介绍了韶冶硫酸系统技术改造和改造后运行情况。改造后设备生产能力提高,有关工艺指标控制改善,并进一步改善环保排放和节能降耗。     

La,Ce,Tb含量对(La,Ce,Tb) BO3发光性能的影响

采用高温固相法合成(La,Ce,Tb)BO3荧光粉,并对该荧光粉进行XRD和SEM分析。结果表明:(La,Ce,Tb)BO3的晶体结构和LaBO3相同,Ce3+,Tb3+的掺入没有改变晶体的结构,发光粉颗粒大小均匀,形貌规则,粒度在5μm左右。研究了(La,Ce,Tb)BO3的光谱性质,在(La,Ce,Tb)BO3的发射和激发光谱中除了有Tb3+的特征发射和激发峰外,还有Ce3+的特征发射和激发峰。     

双乙酰丙酮和2,2'-联吡啶的双核钯(Ⅱ)配合物的量子化学研究

采用B3LYP量子化学方法,对配合物[(bpy)Pd(H-2diacac)Pd(bpy)](PF6)2和二种配体的几何构型进行了优化.通过密度泛函理论(Density Functional Theory,DFT)方法,在LANL2DZ和6-31G·基组水平上,优化了其电子结构.结果表明,桥联配体与Pd(Ⅱ)的作用较螯合配体更强,电荷由桥联配体向Pd迁移的电荷比螯合配体的多.同时也证实了用量子化学方法优化含重金属原子的较大配合物体系的结构是方便可行的,而且DFT方法在此类计算中有更高的准确度.