激光基础知识

介绍了激光和激光器的基础知识，包括激光的基本原理、性能、激光器的种类和结构。     

激光导热仪在橡胶导热性能研究中的应用

简要介绍了激光导热仪的测试原理以及测试工作的注意事项等,详细介绍了如何使用激光导热仪测试炭黑／橡胶复合材料的导热性能,并对测试结果作了恰当的分析。     

激光防护材料的研究与应用

介绍了激光对人眼的伤害和对仪器、设备的破坏。随着激光技术的深入发展和广泛应用 ,激光防护材料的研究也越来越受到重视 ,本文简述了激光防护材料的类型、性能与应用等     

镁合金激光表面处理技术

镁合金激光表面处理能改变表面合金成分,细化表面晶粒,从而提高合金的耐腐蚀和耐磨擦性能.本文介绍了镁合金激光熔融、镁合金激光表面合金化和激光熔覆技术,总结了镁合金激光表面处理技术的基本原则,指出了激光表面处理技术的发展前景.     

煤矿机械应用激光熔覆技术的研究与实践

结合现代采煤机械对耐磨、耐蚀性能的技术要求,对采用激光熔覆技术改善工件表面性能的实践进行了总结,重点介绍了激光熔覆技术在截齿、采煤机高速轴、液压支架及掘进机密封套上的应用,对煤矿机械激光熔覆材料的选择也进行了讨论。     

汽车塑料零部件的激光焊接技术探析

激光焊接技术能满足塑料部件对诸如高焊接强度、焊缝气密性和光学性能优异的质量要求,汽车塑料零部件采用的激光焊接更为方便、经济。本文综述了激光塑料焊接的工艺及其设备,分析了激光焊接的塑料材料、参数和软件,介绍了汽车塑料零部件的激光焊接实例。     

激光清洗技术及应用

介绍了激光清洗的两种机理．一是基体与污物对某一波长的激光吸收系数差别很大,或两者溶、沸点相差悬殊,污物吸收激光能量后汽化挥发,或受热膨胀脱离基体表面;二是基体与污物性能差异不大,在高能量密度、高频率的脉冲激光作用下,污物层内产生分裂应力而与基体脱离．同时介绍了一些激光清洗技术的应用．     

氟化钙晶体的生长和应用研究

CaF2晶体作为一种传统晶体材料,应用十分广泛。文中综合介绍了CaF2晶体在深紫外光刻机的光学元件、激光晶体和被动Q开关三个领域的应用现状及趋势,归总了CaF2晶体具有的优异性能,阐述了CaF2晶体与深紫外准分子激光之间的作用,晶体结构对激光性能的影响,晶体生长和加工等诸多方面的研究进展。     

激光清洗技术及应用

介绍了激光清洗的两种机理：一是基体志污染对某一波长的激光吸收系数差别很大，或两者溶、沸点相差悬殊，污物吸收激光能量后汽化挥发，或受热膨胀脱离基体表面；二是基体与污物性能差异不大，在高能量密度、高频率的脉冲激光作用下，污物层内产生分裂应力而与基体脱离。同时介绍了一些激光清洗技术的应用。     

二氧化碳激光辐照拉伸纤维形变机理研究进展

介绍了二氧化碳激光辐照拉伸纤维的实验方法 ,纤维的形变特征及纤维的结构与性能 ,与传统热拉伸纤维比较 ,二氧化碳激光拉伸纤维最大形变速率超过 10 4s- 1 ,具有较高强度、模量和韧性。     

Recent advances in conjugated polymers for light emitting devices

A recent advance in the field of light emitting polymers has been the discovery of electroluminescent conjugated polymers, that is, kind of fluorescent polymers that emit light when excited by the flow of an electric current. These new generation fluorescent materials may now challenge the domination by inorganic semiconductor materials of the commercial market in light-emitting devices such as light-emitting diodes (LED) and polymer laser devices. This review provides information on unique properties of conjugated polymers and how they have been optimized to generate these properties. The review is organized in three sections focusing on the major advances in light emitting materials, recent literature survey and understanding the desirable properties as well as modern solid state lighting and displays. Recently, developed conjugated polymers are also functioning as roll-up displays for computers and mobile phones, flexible solar panels for power portable equipment as well as organic light emitting diodes in displays, in which television screens, luminous traffic, information signs, and light-emitting wallpaper in homes are also expected to broaden the use of conjugated polymers as light emitting polymers. The purpose of this review paper is to examine conjugated polymers in light emitting diodes (LEDs) in addition to organic solid state laser. Furthermore, since conjugated polymers have been approved as light-emitting organic materials similar to inorganic semiconductors, it is clear to motivate these organic light-emitting devices (OLEDs) and organic lasers for modern lighting in terms of energy saving ability. In addition, future aspects of conjugated polymers in LEDs were also highlighted in this review.     

In Situ Formation of Silicon Carbide Nanofibers on Cordierite Substrates

Twenty-five years of diesel particulate filter (DPF) developments have shown that high-volume ceramic materials are well suited for the harsh requirements of exhaust after treatment. Nevertheless, problems regarding filter reliability and durability associated with the regeneration of the filter have limited their serious application until only recently. To extend useful filter life, the present study has examined the growth of silicon carbide (SiC) nanofibers by a simple carbothermal reduction process on cordierite support surfaces using cheap raw materials such as kaolin, talc, and carbon black. Transmission electron microscopy confirms the crystalline (β - SiC) nature of the nanofibers (10–20 nm diameter). The growth of these nanofibers increases the support-specific surface area restricting the agglomeration of noble metal catalyst particles that otherwise occurs in wash-coat sintering. As a result, fewer particles are needed to perform the catalyst role (at reduced cost) and the support structure can host the catalyst for prolonged times at higher temperatures. As the future will see increasing economic competition in filter fabrication routes and materials, this new design of catalytic DPF promises to play a significant role.     

Effective Control of Laser‐Induced Carbonization Using Low‐Density Polyethylene/Polystyrene Multilayered Structure via Nanolayer Coextrusion

Controlled carbonization is very critical in improving the effect of laser‐induced patterns on a polymer surface. In the present work, the effects of a multilayered structure on the physical and laser‐marking properties of a low‐density polyethylene/polystyrene (LDPE/PS) multilayered film are studied. The multilayered film is prepared using nanolayer coextrusion and treated in air by scanning with a neodymium‐doped yttrium aluminum garnet (Nd:YAG) pulsed laser beam. Based on various analyses, the laser‐induced patterns on the LDPE/PS multilayered film are significantly different from those on a conventional LDPE/PS blend. Furthermore, a mechanism for controlling the carbonized area of a multilayered film is proposed. This study also provides an effective method to fabricate laser‐patterning polymer materials based on a multilayered structure. Nanolayer coextrusion will have broad application prospects in the field of polymer laser marking. Importantly, this work opens up a valuable and viable direction for the practical application of these multilayered polymer materials.     

水厂滤池滤料的分析比较

纤维滤料的比表面积大、过滤精度高、截污量大。分析比较了纤维滤料的性能特点,并结合某水厂滤池的设计情况,将其与传统滤料滤池在运行参数、占地面积、造价等方面进行了比较讨论,说明了采用新型纤维滤料的合理性和优越性,以供技术人员在选择滤池滤料时参考。     

理想纤维过滤材料的影响因素

分析了影响纤维过滤材料效率的几个重要因素,为合理设计理想的纤维过滤材料提供了理论依据,同时提出了开发高性能过滤材料的途径。     

The Effect of Filter Cakes on Filter Medium Resistance

Abstract

The high resistance of a filter medium to fluid flow is a universal problem affecting many industries. The small thickness of the filter media makes local pressure and porosity measurements impractical. Analysis of the continuum equations and boundary conditions provide a basis for defining a relative medium resistace. Experiments are conducted on three particulate materials and on three different high flow rate filter media. The results show that the increase in medium resistance varies up to about four times the resistance of a clean filter medium with no cake present. The results also show that in most cases the relative resistance is dependent upon cake height.     

智能化高能激光防护材料新进展

激光技术的不断进步，尤其是其在军事领域的实战化应用，使得针对高能激光的防护要求不断提高。本文首先介绍了高能激光武器在未来战争中的重要地位，总结分析了激光隐身和高能激光防护材料的研究进展,提出兼具激光隐身和防护功能的智能化激光隐身材料是未来激光防护材料的发展趋势和方向。之后，详细阐述了智能化激光防护材料的防护思路，并按防护机理梳理了现阶段具有智能化激光防护特征的材料体系和防护结构，分别分析了其优缺点及发展方向。目前智能化激光防护材料的研究尚在起步阶段，尚未能有一种已知材料体系可以满足激光隐身和高能激光防护兼容的需求，针对新材料的开发刻不容缓。因此，本文对智能化激光防护材料的发展趋势也进行了预测和探讨。     

Technical study of the effect of CO2 laser surface engraving on the colour properties of denim fabric

The laser engraving process allows short‐time surface designing of patterns with precision, desired variety, size and intensity on a wide range of textile surfaces with minimum damage to the material. Because of this, it is possible that laser engraving applied to textile materials can make the fabric look faded and worn out without the use of any of the chemicals that are usually required in the conventional colour‐fading process. In the present study, laser engraving was applied to denim fabric in order to evaluate its effect on some colour‐related properties. Two laser process variables, namely, resolution and pixel time, were studied thoroughly. The laser power density was enhanced in response to the increased level of pixel time and resolution. Under the effect of high laser power density, a paler surface appearance was achieved for the denim fabrics with the largely reduced K/S_sum values, indicating that the amount of dye present on the denim fabric was decreased significantly. In addition, a green–yellow shade was observed in the denim fabric samples after laser engraving.     

Filter elements from high-purity quartz glass for flow-through equipment for concentration of silica-containing feedstock

The results of a study on creation of a porous, permeable material based on molten quartz and technology for manufacturing filter elements from this material are presented. The compositions of the developed materials, process parameters, and physicotechnical and filtering properties are reported. The filter elements developed were successfully tested in industrial conditions.     

Regeneration of oils used for deep frying: A comparison of active filter aids

A number of products are promoted for the purpose of regenerating used frying oils. These materials are referred to as “active” filter aids. They are purported to adsorb polar compounds, which are the products of oil degradation, and to retain them for removal by filtration. To evaluate some of these materials, portions of a used oil were treated with each of several “active” filter aids and filtered in a commercial-type recirculating oil filter. The triglycerides and any adsorbed compounds were extracted from the filter cake with a series of increasingly polar organic solvents. The composition of each of the filter cakes was quantitatively determined. The materials tested in this study were diatomaceous earth, acid-activated bleaching earth, activated aluminas, silica, carbon and synthetic magnesium silicate. Significant differences in the adsorbent characteristics of the materials were found. Adsorption of polar oil degradation compounds ranged from 2 mg of polar compounds per gram of diatomaceous earth to about 200 mg/g magnesium silicate.