光调制直接重写磁光双层耦合膜磁基本特性的一种解耦方法

采用FFT方法对光调制直接重写磁光双层耦合膜的磁基本特性进行解耦,得到各单层薄膜在耦合状态下的特性,并用于分析计算磁光双层耦合膜之间的层间耦合能。     

光调制直接重写磁光双层耦合膜磁基本特性的一种解耦方法

采用ＦＦＴ方法对光调制直接重写磁光双层耦合膜的磁基本特性进行解耦,得到各单层薄膜在耦合状态下的特性,并用于分析计算磁光双层耦合膜之间的层间耦合能σω。     

有机光导液晶光阀(透射式)及其性能的研究

本文报道用聚乙烯咔唑-2,4,7三硝基芴酮电荷转移复合物作光导层,与向列型及胆甾向列型混合液晶组成的夹心池结构制成的扭曲场效应、相变存储效应及动态存储效应三种直流透射式光阀及其性能的研究结果。制得的光阀均有明显开关效应。此外,还详细研究了扭曲场效应液晶光阀的阈值电压、对比度及上升时间与写入光功率的依赖关系。用白光写入,He-Ne激光读出,在扭曲场效应光阀上可实现非相干光-相干光转换,得到图象。用MTF法测得的光阀分辨率为34lps/mm。     

掺杂萘并吡喃的涂料光致变色性能研究

制备了一种能用太阳光（或紫外光）控制色彩变换的涂料。研究表明，通过光调控开关，将有机光功能材料的信息存储与显示功能在高分子载体（涂料）中得到充分展示。光调控的、智能化的新材料，使色彩变化多样，能丰富人们的生活。     

In:Ce:Mn:LiNbO3晶体的全息存储性能

原料采用固液同成分配比,在LiNbO3（LN）晶体中掺入质量分数为0．1％CeO2和0．015％MnCO3,摩尔分数分别为0,1％,2％和3％的In,用提拉法生长In：Ce ：Mn ：LN晶体。测试了In ：Ce ：Mn ：LN晶体的红外透射光谱和抗光损伤能力。结果表明：3％In ：Ce ：Mn ：LN晶体的OH振动吸收峰紫移到3508cm^-1位置;其抗光损伤能力比Ce ：Mn ：LiNgO3晶体提高2个数量级以上。利用二波耦合光路测试晶体的写入时间（τw）、擦除时间（τc）和衍射效率（η）,计算晶体的动态范围（M^#）,研究In^3＋掺量对Ce ：Mn ：LN晶体光折变性能的影响。结果表明：In ：Ce ：Mn ：LN晶体是比Ce ：Mn ：LN晶体综合性能更好的全息存储材料。     

国外信息记录材料文献题录

<正>标准的自旋阀构造的存储效应 J Appl Phys（USA）87（9,Pt.2）4951～4953（2000）铁磁性/反铁磁性多层膜的新存储效应 J Appl Phys（USA）87（9,Pt.2）5069～5069（2000）纳米尺寸磁性元件的相互作用和开关场分布 J Appl Phys（USA）87（9,Pt.2）5105～5107（2000）     

低辐射玻璃

在平板玻璃表面镀覆-层金属氧化物薄膜,该膜能使辐照于玻璃的远红外光（波长为45～25μm）被反射而不透过或吸收,从而降低玻璃的热辐射通过量,具有此类功能的玻璃被称为低辐射玻璃（LOW—E玻璃）。     

纳米TiN表面改性的研究及其在ACM胶中的应用

采用自制的大分子表面改性剂对纳米TiN进行表面改性,对改性前后的纳米TiN进行红外光谱分析（FTIR）、热重分析（TGA）、粒径分析、接触角等表征。结果表明,大分子改性剂和纳米TiN的表面发生化学键合,有效地阻止了纳米TIN的团聚,使得纳米T．N疏水性提高。用改性后的纳米TiN填充丙烯酸酯橡胶（ACM）,制备纳米TiN／ACM复合材料,透射电镜（TEM）观察到纳米TiN颗粒在ACM基体中分散良好;复合材料性能检测结果显示：材料的常规力学性能、耐油、耐热空气老化和耐磨性能均有明显提高。     

基于分子间作用力组装的镁铝水滑石光稳定剂及其性能研究

采用共沉淀-离子交换法制备了十二烷基硫酸根（SDS）插层镁铝水滑石（SDS-LDH）,然后借助水滑石层间客体分子间作用力将光稳定剂2-羟基-4-正辛氧基二苯甲酮（UV-531）中性分子引入镁铝水滑石层间,构筑了共插层结构镁铝水滑石光稳定剂UV-SDS-LDH。采用XRD、FT-IR、UV-Vis和SEM等表征手段对其晶相结构、组成、紫外吸收性能和形貌进行表征。研究发现,UV-SDS-LDH形成了共插层结构,具有强的紫外吸收能力;插层组装大幅度提高了UV-531的耐迁移性,使其迁移率由83%降低至50.5%。由于其特殊的结构和组成,UV-SDS-LDH明显增强了聚丙烯（PP）的热稳定性和耐光老化性能,使PP 50%失重温度由411℃提高到441℃,光老化指数由65.9×10^-3减小至23.9×10^-3,在PP领域具有潜在的应用价值。该研究为新型水滑石基功能材料的构筑和盐湖镁资源的利用提供了新思路。     

衍射效率随光子晶格写入时间变化的研究

从双光束耦合实验入手,在非同时读出条件下测量LiNbO3∶Fe晶体两波耦合过程中,不同写入角度(光子晶格周期)、不同的读写条件下,衍射效率随时间的变化。结果表明衍射效率随时间出现振荡变化。用小周期写入时,不容易出现振荡。同时用o光写入e光读出时,得到的光子晶格稳定且衍射效率较高。另外从理论上定性分析了衍射效率随时间的振荡变化。认为这是由空间二次谐波和动态能量转移及瞬态条纹位错引起的。通过实验与理论上的分析,得出光子晶格的最佳写入时间为第一个峰值出现所对应的时间。     

Electrochemical corrosion and materials properties of reactively sputtered TiN/TiAlN multilayer coatings

TiN/TiAlN multilayers of 2 μm thickness were successfully prepared by reactive DC magnetron sputtering method. XRD pattern showed the (1 1 1) preferential orientation for both TiN and TiAlN layers. XPS characterization showed the presence of different phases like TiN, TiO₂, TiON, AlN and Al₂O₃. Cross sectional TEM indicated the columnar growth of the coatings. The average RMS roughness value of 4.8 nm was observed from AFM analysis. TiN/TiAlN coating showed lower friction coefficient and lower wear rate than single layer coatings. The results of electrochemical experiments indicated that a TiN/TiAlN multilayer coating has superior corrosion resistance in 3.5% NaCl solution.     

Interface evaluation on the brazed system of AlN-Ticusil-Graphite

The graphite-Ticusil-AlN system was joined under vacuum or flowing atmospheres, such as 5% H₂-95% N₂ and argon atmosphere, to investigate the morphology and forming mechanism of the reaction phases at the interfaces of AlN-Ticusil-graphite layers. Scanning electron microscopy, energy-dispersive spectroscopy, electron probe microanalysis, and transmission electron microscopy were used to examine the composition and structure of the interface products. The AlN-Ticusil interface could be divided into two layers, the TiN layer and titanium-copper–rich compound layer. The thickness of the TiN layer was only affected by the joining temperature and could be regarded as mainly dependent on the reaction. The titanium-copper compound layer was composed of (Ti,Cu,Al)₆N column when joined under vacuum and was composed of TiN particles when joined in a flowing atmosphere. The products on the graphite-Ticusil interface were also examined as TiC, which was strictly bonded with graphite and Ticusil filler.     

Surface Cracking in Layers Under Biaxial, Residual Compressive Stress

Thin two-phase, Al₂O₃/ t -Zr(3Y)O₂ layers bounded by much thicker Zr(3Y)O₂ layers were fabricated by co-sintering powders. After cooling, cracks were observed along the center of the two-phase, Al₂O₃/ t -Zr(3Y)O₂ layers. Although the Al₂O₃/ t -Zr(3Y)O₂ layers are under residual, biaxial compression far from the surface, tensile stresses, normal to the center line, exist at and near the surface. These highly localized tensile stresses can cause cracks to extend parallel to the layer, to a depth proportional to the layer thickness. A tunneling/edge cracking energy release rate function is developed for these cracks. It shows that for a given residual stress, crack extension will take place only when the layer thickness is greater than a critical value. A value of the critical thickness is computed and compared with an available experimental datum point. In addition, the behavior of the energy release rate function due to elastic mismatch is calculated via the finite element method (FEM). It is also shown how this solution for crack extension can be applied to explain cracking associated with other phenomena, e.g., joining, reaction couples, etc.     

Preparation of Crack-Free Nanocomposite Ceramic Membrane Intermediate Layers on α-alumina Tubular Supports

The objective of this work was to develop a crack-free membrane intermediate layer on tubular ceramic supports via dip-coating. TiO₂ submicron powder, Boehmite as a coupling agent, and SiO2 nanopowder as low melting-point sintering aid were used to deposit a thin and crack-free nanocomposite layer onto α-Al₂O₃ supports. Effects of key parameters such as solid content, number of coated layers, the presence of coupling agent, and a low melting point nanopowder on physicochemical properties like the thickness, microstructure, pore size, pure water flux, and gas permeance of the final modified ceramic supports were investigated. The obtained results showed that after twice coating of support in 3 wt.% bidispersed TiO₂-Boehmite suspension, the pore size of the alumina substrate, ～0.6 micron, was reduced to ～0.1 by the uniform membrane intermediate layers with low permeation resistance could be prepared. Moreover, by adding SiO₂ nanopowder, sintering temperature of intermediate layers decreases considerably (1000 to 700°C).     

Analysis of the mechanical properties of TiN/Ti multilayer coatings using indentation under a broad load range

In this study, physical vapor deposition was used to prepare TiN/Ti multilayer coatings as well as the corresponding monolithic coatings for comparison. Nanoindentation using a large load range (5–4800 mN) and finite element method (FEM) simulations were conducted to investigate the influence of various multilayer structures on the mechanical behavior of multilayer coatings. The nanoindentation results show that the TiN/Ti multilayer coating has the maximum hardness and Young's modulus while retaining good crack resistance and fracture toughness. The FEM results show that increasing the number of layers in the multilayer coatings reduced the hardness and Young's modulus as well as the maximum stress, while it increased the equivalent plastic strain. As the layer thickness ratio increased, both the hardness and Young's modulus gradually increased, and the stress in the coating reached its maximum at the highest thickness ratio. In addition, to consider the effect of the indentation depth on the coating, the influence of the number of layers and the layer thickness ratio on the multilayer coating is combined into the indentation response of the multilayer coating. Therefore, we establish an expression describing the relationship between the number of layers and the ratio of the layer thickness to the mechanical properties of TiN/Ti multilayer coatings.     

Fracture Energy of Epoxy Interfaces with Layers of Different Silane Coupling Agents

We investigated the fracture energy, Gc, and the threshold fracture energy, Gth, in water at 80°C of interfaces between epoxy and layers of five silane coupling agents: (3-glycidoxypropyl)trimethoxysilane (GPS), (3-aminopropyl)trimethoxysilane (APS), [3-(phenylamino)propyl]trimethoxysilane (PAPS), (3-mercaptopropyl)trimethoxysilane (MPS), and [3-(2-aminoethylamino)propyl]trimethoxysilane (AEAPS) on the native silicon oxide surface. While 10-nm-thick layers of these all had similar high Gc, APS had the best overall values of Gth, but all adhesion promoters, except for AEAPS, performed roughly similarly. The results from the XPS analysis of the silicon side of the fracture surfaces suggest that for all silane layers, the fracture occurs somewhere within that layer. When the silane coupling agents were added to the epoxy, the samples with the higher threshold fracture energies exhibited a thicker layer of the epoxy remaining on the native silicon oxide surface. Silane coupling agents that perform well as deposited layers do not necessarily perform well as additives to epoxies.     

磁光多层膜的Kerr增强效应的研究

从相干光迭加的普遍原理出发,研究了双层膜系的磁光效应,从理论上导出了双层膜系Ｋｅｒｒ角反射率和椭圆率与磁光双层膜各膜层的光学参数和膜厚的关系表达式。并验证该表达式的正确性。提出利用双层膜系磁光效应的表达式计算磁介质薄膜介电张量矩阵的矩阵元,从而计算磁介质薄膜的光学常数的方法。研究结果表明,该方法能够解决测量介电张量矩阵的矩阵元方面存在的困难。     

生物质锅炉积灰特性与露点腐蚀

以ND钢为研究对象,选取316 L不锈钢为对比材料,主要研究了65 t·h^-1生物质循环流化床锅炉烟气深度冷却条件下的积灰与露点腐蚀耦合特性。对积灰和腐蚀层进行了XRF、XRD、SEM和EDS分析。实验结果表明：实验管件表面沉积物可分为腐蚀层、耦合层和灰沉积层（NH₄Cl、SiO₂和（NH₄）₂SO₄）。耦合层包含了灰沉积物和金属腐蚀产物,且与灰沉积层黏结紧密易剥落;腐蚀层多为金属的氯化物和氧化物,其厚度随实验进口水温降低而降低,当管壁温低于烟气水露点时,ND钢被腐蚀的程度急剧加重。在实验条件下,ND钢的抗露点腐蚀能力弱于316L不锈钢。     

Temperature dependence of the interfacial dielectric loss process in glass bead-filled polyethylene

The temperature dependence of the interfacial dielectric loss process in glass bead-filled high density polyethylene (HDPE) due to an interfacially adsorbed water layer has been studied. The frequency of maximum dielectric loss shifts to lower frequencies with decreasing temperature. This is thought to be due to decreasing mobility of the free charge carriers in the adsorbed water layer, resulting in the reduced conductivity of the layer. The shifting of the loss peaks with temperature can be described with the well-known Arrhenius relation. The energy of activation, as obtained from this relation, shows a stron dependence on the thickness of the adsorbed layer. For thinner layers a higher activation energy is found, indicating that the charge carriers are increasingly affected by the presence of a layer of bound charges on the glass surface. This thickness dependence of the activation energy offers some possible applications. First, information on the water layer thickness can be extracted from the energy of activation, and second, it becomes possible to study the effect of interfacial modifications such as the application of coupling agents.     

Gas-to-Particle Conversion in the Particle Precipitation–Aided Chemical Vapor Deposition Process I. Synthesis of the Binary Compound Titanium Nitride

Particle precipitation-aided chemical vapor deposition (PP-CVD) is a modification of the conventional CVD process, where an aerosol is formed in the gas phase at an elevated temperature, and particles are deposited on a cooled substrate. The synthesis of titanium nitride (TiN), using titanium tetrachloride vapor (TiCl₄), nitrogen (N₂), ammonia (NH₃), and hydrogen (H₂), by the PP-CVD process is studied. TiN is formed by a heterogeneous reaction, using TiCl₄, N₂, H₂, whereas simultaneously TiCl₄ and NH₃ react to form an aerosol. The activation energy of this homogeneous reaction is on the order of 100 kJ/mol. The powder formation process is determined by the dissociation of a titanium containing intermediate species. At low temperature differences between substrate and gas phase (i.e., < 2 K), only dense columnar microstructures, with growth rates of around 20 μm/h, are observed. At these temperature differences no particle deposition is observed. The layers are formed by a molecular diffusion controlled CVD growth mechanism. Porous coherent layers are found in experiments, where intermediate temperature differences are applied (i.e., approximately 2–10 K). The observed interconnection of the particles has to originate from a heterogeneous reaction. Apparently, under these conditions the heterogeneous reaction is fast enough, with respect to the particle precipitation rate, to interconnect the precipitated particles. A further increase in temperature difference between the susceptor and the gas phase only leads to loose powder deposits. In principle, the PPCVD process is a suitable method for the synthesis of thin porous layers of ceramics. To obtain uniform coherent porous layers two separate reaction mechanisms are required under the same experimental conditions. There should be a homogeneous reaction in the gas phase as well as a heterogeneous reaction, which is controlled by surface kinetics, in order to interconnect precipitated particles to obtain a coherent porous layer. Porous ceramic layers can be formed as long as the particle precipitation rate is slow enough with respect to the heterogeneous reaction rate.