以自蔓延高温合成SiC颗粒为增强体的光学/仪表级铝基复合材料

尝试采用自蔓延高温合成 (SHS)、具有近球形特征且表面粗糙的新型 Si C颗粒 ,以替代传统的角状磨料级 Si C颗粒 ,作为光学 /仪表级的高体分 Si Cp/Al复合材料的增强体。研究结果表明 :与传统角状 Si C颗粒相比 ,SHS- Si C颗粒的无棱角、近球形几何特征 ,使其附近铝基体中的应力集中程度显著降低 ,进而使材料的强度包括表征尺寸稳定性的微屈服强度明显提高 ;SHS- Si C颗粒所特有的粗糙表面形貌 ,使 Si C- Al之间的界面结合通过机械镶嵌机制得到了进一步的增强 ,跨越界面的载荷传递效率进一步提高 。

主动成形准各向同性CFRP复合材料反射镜的铺层设计

要实现高精度的碳纤维增强聚合物(CFRP)复合材料反射镜的主动成形,使用面内刚度和弯曲刚度均为准各向同性的层合板非常重要。先建立对称层合板几何模型,根据经典层合板理论,得到准各向同性的要求下,正则化面内刚度系数、弯曲刚度系数以及正则化几何因子应满足的条件,确定单层组数最大的铺层方式,并提出以正则化刚度系数和几何因子表示的两种铺层顺序优化方法。然后,针对M40/环氧648材料,通过编程得到不同定向单层数量下的最佳铺层顺序。最后,用两种优化方法下的优化结果分别建立口径500 mm的壳体模型,经有限元静力学分析,得到模型上相同半径上各节点在光轴方向的变形量,并进行数据处理。结果表明:总层数为24层时,铺层顺序为[45/-15/-75/90/15/-45/-30/60/-60/0/30/75]s的层合板弯曲刚度的均匀性最佳。采用正则化刚度系数优化方法 Di*j=Ai*j,可得到准各向同性层合板铺层顺序的最优化方案;当总层数一定且单层组数最大时,增加定向单层数,将增加层合板弯曲刚度的均匀性。采用正则化刚度系数法对铺层顺序进行优化为准各向同性CFRP复合材料反射镜的铺层设计提供了一种方法。

石墨烯基光学复合材料及其光学应用

石墨烯是近年来发现的一种新型二维晶体碳材料,由单层碳原子构成,具有规则六方对称的蜂巢结构,使其表现出优异的力学、电学和光学性能,近年来迅速成为材料学及光电化学等领域研究热点。本文综述了石墨烯基光学复合材料及其光学应用的研究进展,展望了石墨烯基光复合材料的光学应用前景及发展方向。

高折射率玻璃微珠的研究现状与展望

从高折射率玻璃微珠性能参数的影响因素、化学组成系统的选择。

EXPERIMENTAL STUDY ON OPTIC PERFORMANCES OF OPTIC FIBER BRAIDED IN CARBON FIBER BRAIDED COMPOSITES

D braiding technology has stimulated a great deal of interest in the world at large and been widely used in aerospace, military, civil construction and medical fields. Although 3 D braided composites have many good features, their features are very complicated. Optic fiber sensors can be multi braided into 3 D braided composites to fulfill a new kind of 3 D smart composites to monitor RTM process, study mechanical behaviors and damage states after molding, and monitor its own condition during service life. Since optic performances of optic fibers have direct and important relation to the performances of optic fiber sensors, experimental research is done to devise a method to incorporate the optic fiber into a 3 D structure. The optical performances of the braided optic fibers are tested and compared with the original one to study the optic performances of optic fibers, before their being braided into composites and after the RTM process.

Preparation and characterization of ZnSe/CdSe core-shell microspheres

The preparation of Zn Se/Cd Se core-shell structure nanocomposites by using the re-prepared Zn Se microspheres as the template under the hydrothermal condition was presented. The influence of different mole ratios of ZnS e to Cd（NO3）2 on the morphology and structure of the final product was investigated. And the performances of ZnS e/Cd Se core-shell structure nanocomposites were characterized by the means of X-ray diffraction（XRD） analyses, scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and photoluminescence（PL） spectroscopy. The results indicate that the core-shell structure product can be prepared, when the mole ratio of Zn Se to Cd（NO3）2 is larger than 1：1; and the product will be ball solid structure, when the mole ratio of Zn Se to Cd（NO3）2 is equal to 1：1. The photo luminescence results show that Zn Se/Cd Se core-shell structures have high photo luminescence emission properties, and the product with mole ratio of Zn Se to Cd（NO3）2 being 1：0.5 has the best luminescence properties.

回归式反光膜的研制

本文介绍了回归式反光膜的一般原理 ,对研制过程中的关键问题进行了探讨 ,并研制出质量稳定的回归式反光膜。

回归式反光膜的研制

回归式反光膜是一种新型的光学复合材料,具有独特的反光性能。它在受到入射光照射后,可基本上按与入射光平行而相逆的方向返回大部分光能,因而不同于常见的镜面反射和漫反射,它能更好地从光源附近观察到贴反光膜的物体,使之非常醒目。该种材料被广泛用于交通标志的制造,此外在机场码头、广告牌、服装等领域也得到了广泛应用。由于该产品成本低、价值高、用途广,具有诱人的商业前景,因而吸引了国内外众多研究机构、公司竞相开发研究。本文的研究工作是立足于国产设备及条件,研制出质量、性能稳定的回归式反光膜,通过改进生产工艺及条件提高反光膜的性能。

Photoluminescence behavior and visible light photocatalytic activity of ZnO,ZnO/ZnS and ZnO/ZnS/α-Fe_2O_3 nanocomposites

In order to achieve effective, economic, and easily achievable photocatalyst for the degradation of dye methyl orange（MeO）, ZnO, ZnO/ZnS and ZnO/ZnS/α-Fe2O3 nanocomposites were prepared by simple chemical synthetic route in the aqueous medium. Phase, crystallinity, surface structure and surface behavior of the synthesized materials were determined by X-ray diffraction（XRD） and Brunauer-Emmett-Teller analysis（BET） techniques. XRD study established formation of good crystalline ZnO, ZnO/ZnS and ZnO/ZnS/α-Fe2O3 nanomaterials. By using intensity of constituent peaks in the XRD pattern, the compositions of nanocomposites were determined. From the BET analysis, the prepared materials show mesoporous behavior, type Ⅳ curves along with H4 hysteresis. The ZnO/ZnS/α-Fe2O3 composite shows the largest surface area among three materials. From the UV-visible spectra, the band gap energy of the materials was determined. Photoluminescence spectra（PL） were used to determine the emission behavior and surface defects in the materials. In PL spectra, the intensity of UV peak of ZnO/ZnS is lowered than that of ZnO while in case of ZnO/ZnS/α-Fe2O3, the intensity further decreased. The visible emission spectra of ZnO/ZnS increased compared with ZnO while in ZnO/ZnS/α-Fe2O3 it is further increased compared with ZnO/ZnS. The as-synthesized materials were used as photocatalysts for the degradation of dye MeO. The photo-degradation data revealed that the ZnO/ZnS/α-Fe2O3 is the best photocatalyst among three specimens for the degradation of dye MeO. The decrease of intensity of UV emission peak and the increase of intensity of visible emission cause the decrease of recombination of electrons and holes which are ultimately responsible for the highest photocatalytic activity of ZnO/ZnS/α-Fe2O3.

Observation of interface of two kinds of bi-metal composite parts prepared by thixo-forging

Two kinds of bi-metal composite parts （Sn-15%Pb and Pb-22%Sn bi-metal system, and Al-7%Si and SiCp/6061 MMC bi-metal system） were prepared by the strain-induced melt activated thixo-forging. The interfaces of the bi-metal composites were observed by OM and SEM. The observations show that the semisolid metals keep independence during thixo-forging. The solid phases in the semisolid slurries maintain their original morphologies after thixo-forging. The liquid phases near the interface mix together and form a thin layer. The interfaces are bonded firmly with the metallurgical bonding. No oxide layers are found at the interfaces. Strengths of the interfaces were investigated by the micro-hardness test. The experimental results show that the composite interfaces have high strength. However, the agglomerated enhancing particles cause fine defect on the interface of the Al-7%Si and SiCr/6061 MMC bi-metal composite.

Influence of processing parameters on laser metal deposited copper and titanium alloy composites

The laser metal deposition （LMD） was conducted on copper by varying the processing parameters in order to achieve the best possible settings. Two sets of experiments were conducted. The deposited composites were characterized through the evolving microstructure, microhardness profiling and mechanical properties. It was found that the evolving microstructures of the deposited composites were characterized with primary, secondary and tertiary arms dendrites, acicular microstructure as well as the alpha and beta eutectic structures. From the two sets of experiments performed, it was found that Sample E produced at a laser power of 1200 W and a scanning speed of 1.2 m/min has the highest hardness of HV （190±42） but exhibits some lateral cracks due to its brittle nature, while Sample B produced at laser power of 1200 W and a scanning speed of 0.3 m/min shows no crack and a good microstructure with an increase in dendrites. The strain hardening coefficient of the deposited copper composite obtained in this experiment is 3.35.

Resin Matrix/Fiber Reinforced Composite Material, Ⅱ: Method of Solution and Computer Code

According to a mathematical model which describes the curing process of composites constructed from continuous fiber-reinforced, thermosetting resin matrix prepreg materials, and the consolidation of the composites, the solution method to the model is made and a computer code is developed, which for flat-plate composites cured by a specified cure cycle, provides the variation of temperature distribution, the cure reaction process in the resin, the resin flow and fibers stress inside the composite, the void variation and the residual stress distribution.

Facile preparation of self-assembled MXene@Au@CdS nanocomposite with enhanced photocatalytic hydrogen production activity

Photocatalytic hydrogen production is considered a promising approach to generating clean sustainable energy.However,the conventional co-catalyst(e.g.,Pt)used in photocatalytic hydrogen production is high-cost and difficult to obtain.Here,we designed and prepared a ternary nanocomposite MXene@Au@Cd S,which can be used in the field of efficient and excellent photocatalytic hydrogen production.The MXene@Au@Cd S has a hydrogen production rate of 17,070.43μmol g^-1h^-1(tested for 2 h),which is 1.85 times that of pure Cd S nanomaterials.The improved hydrogen production performance of the MXene@Au@Cd S is attributed to:(i)MXene provides more active adsorption sites and reaction centers for Au and Cd S nanoparticles;(ii)the synergistic effect of Au’s strong surface plasmon resonance expands the optical response range of Cd S.Therefore,this work solves the problem of the solid connection between the surface functional groups of photocatalyst,and achieves rapid interface charge transfer and long-term stability during the hydrogen production.

Optical and electrical properties of blue-light polyfluorence/porous silicon composites

Optical and electrical properties of composites formed by mixing porous silicon （PS） and poly （9, 9- diocty-2, 7-fluorene- co-4, 4＇-butoxydiphenyl） （PFP） have been studied by Fourier transform-infrared spectroscopy （FT-IR）, scanning electron microscopy （SEM） and photoluminescence （PL） spectroscopy. The optical spectra show that porous silicon is incorporated into the polymer without significant change in the polymer properties. The FT-IR spectroscopy has detected the existence of specific interactions, which may be attributed to non-conjugated alkoxy segment. By fitting the current-voltage （/-V） curve of PFP/PS structure with the modified standard ecluation, the n factor and I0 are cletermined