Electron beam damage of amorphous synthetic polymers

The electron beam damage of amorphous polymers (PVC, PVDC, PTFE, PVDF, Hypalon, PES, Horizon and PDMS) has been measured by the elemental loss using EDX analysis. An attempt has been made to identify and eliminate the experimental error which would influence the measured decay curves. Only Cl and F in some polymers were found to be volatile. The PVC-Cl decay curves were compared with UV and IR spectra at different stages of irradiation and it has been concluded that some Cl is trapped in a more stable structure with conjugated double bonds. The formation of isolated double bonds and their destruction has been revealed by a staining technique for PVC, PMMA, PS and PC. It is likely that the mechanism of formation of isolated double bonds and their conversion to a more stable structure with conjugated double bonds is valid generally for all polymers. The staining peak can therefore be used as a universal technique for the beam sensitivity measurement.     

光弹性贴片中用宽条带法分离主应变的研究

在光弹性贴片法中，通常利用剪应力差法和斜射法来分离主应变。对于应变梯度不大的平面可以采用条带法来分离主应变，但其应用性较差。本文研究用宽条带法来分离主应变，使条带法得到了进一步的推广和应用，从而为解决复合材料、陶瓷材料等新型材料的表面应力测定问题提供了一种新的研究方法。     

工程塑料在电子设备减重方面的应用

文中主要通过工程塑料的应用实现电子设备减重的目的.首先对电子机箱结构部分各个主要功能进行分析,讨论用工程塑料替换金属材料的可行性.可通过替换承力部件而非导热部件实现工程塑料的应用.然后针对工程塑料普遍不导电的问题,采用金属涂层提高其导电性.选用了几种不同的导电涂料进行实验,测试它们的导电性能及三防性能.最后采用塑料及尼...     

Investigation of fluorescent lamp phosphors using the combined CL and EDS modes of the SEM

The phenomenon of cathodoluminescence (CL) potentially offers the ideal tool for studying the phosphor materials used in fluorescent lamps, since it can be used directly on processed or unprocessed powders, on coatings in tubes, or on sections cut from tubes. Using examples of both single component materials and multi-component blends, it is demonstrated how a relatively unsophisticated dispersive CL system attached to a scanning electron microscope (SEM) can be used expediently in the extensive study of such phosphors. These studies can be significantly enhanced when other complementary modes of the SEM (e. g. the energy-dispersive x-ray analysis facility) are combined with the CL mode. The strength of the combined technique lies in the major role it can play in materials and processing aspects of the powders themselves, in the processing of the lamps (e.g. by optimising such parameters as coating thickness, packing density etc.), and in diagnostic studies of poor materials or lamps (e.g. by locating rogue particles/components and identifying their origin). The technique also provides a convenient method of studying the temperature stability of selected phosphors.     

轴类镀层结构材料力学性能声学表征方法研究

针对轴类镀层结构材料力学性能无损表征方法开展理论和实验研究,对于表面工程的质量检测与评价具有重要意义。利用自主开发的超声显微测量系统与PVDF线聚焦探头,对不同厚度的轴类镀层材料进行散焦测量。针对轴类试件表面波传播路径与散焦距离的非线性关系,分析了线聚焦探头几何尺寸与散焦距离和试件轴径间的匹配关系,优化检测参数,并在V(f,z)分析法的基础上,采用相位相关分析法获得轴类镀层材料的实验频散曲线。结合镀层材料声波传播特性,采用基于模拟退火的粒子群优化算法(PS-B-SA)将理论频散曲线与实验频散曲线相拟合,反演轴类镀层结构材料的声学参数,进而表征镀层材料的弹性常数。多个不同厚度轴类镀层结构材料弹性常数及镀层厚度的反演结果与实际值相吻合,表明该测量方法可靠、结果准确。该研究成果为轴类镀层结构力学性能无损检测提供了技术手段,也为工程材料表面工程加工性能的评价提供了新方法。     

Creating internal conductivity in dry biological SEM samples by a simple vapour treatment

Internal sample conductivity in scanning electron microscopy can be a valuable alternative to metal coating. Proton conductivity may be used for this purpose. Many solid materials with active hydrogen atoms, such as hydrogen‐ and ammonium‐salts, organic acids, and even ice, are protonic conductors or semiconductors. Here we present a method to generate proton conductivity in dry biological materials. A simple treatment with hydrogen chloride gas or hydrochloric acid vapour for a few minutes provides sufficient conductivity for many samples. After a removal of excess hydrogen chloride vapour with a vacuum desiccator, the objects may be examined in the SEM without metal coating. The use of internally conductive samples extends the range of easy‐to‐perform SEM preparation techniques. It is advantageous for material contrast imaging of uncoated samples, and it can be used in combination with metal coating to enhance conductivity on difficult samples with complex overlapping surfaces, where simple metal coating does not reliably eliminate charging problems.     

A fluorescence staining method for the examination of microorganisms on natural substrates.

A fluorescence staining technique is described which uses the magnesium salt of 1-anilino-8-naphthalene sulfonic acid as a protein stain. At a concentration of 2.5 or 3.0 mg ml-1 in distilled water or phosphate buffer the compound does not fluoresce under ultra-violet or far blue illumination until it is bound to a protein or similar compound. It can be applied to natural substrates such as soil, food materials, organic material in water, etc., and can be examined immediately without any washing procedures. The application of this staining method to detect microorganisms on dead green algae (detritus) is described.     

Far‐reaching geometrical artefacts due to thermal decomposition of polymeric coatings around focused ion beam milled pigment particles

Focused ion beam and scanning electron microscope (FIB‐SEM) instruments are extensively used to characterize nanoscale composition of composite materials, however, their application to analysis of organic corrosion barrier coatings has been limited. The primary concern that arises with use of FIB to mill organic materials is the possibility of severe thermal damage that occurs in close proximity to the ion beam impact. Recent research has shown that such localized artefacts can be mitigated for a number of polymers through cryogenic cooling of the sample as well as low current milling and intelligent ion beam control. Here we report unexpected nonlocalized artefacts that occur during FIB milling of composite organic coatings with pigment particles. Specifically, we show that FIB milling of pigmented polysiloxane coating can lead to formation of multiple microscopic voids within the substrate as far as 5 μm away from the ion beam impact. We use further experimentation and modelling to show that void formation occurs via ion beam heating of the pigment particles that leads to decomposition and vaporization of the surrounding polysiloxane. We also identify FIB milling conditions that mitigate this issue.     

PC微流控芯片黏接筋与溶剂的协同辅助键合

为了在微流控芯片上形成封闭的微通道等功能单元,克服热压键合中微流控结构的塌陷和热压所致芯片微翘曲对后续键合的影响,提出了一种适用于硬质聚合物微流控芯片的黏接筋与溶剂协同辅助的键合方法。以聚碳酸酯(PC)微流控芯片为研究对象,通过热压法在PC微流控芯片上的微通道两侧制作凸起的黏接筋,通过化学溶剂丙酮微溶PC圆片的表面,然后将PC圆片与带有黏接筋的PC微流控芯片贴合、加压、加热,从而实现微流控芯片的键合。分析了键合机理,并对键合工艺参数进行了优化。实验结果表明:键合质量受丙酮溶剂溶解PC圆片的时间和键合温度的影响,能够保证键合质量的最佳键合温度为80~90°,溶解时间为35~45s,芯片的键合总耗时为3min。与已有键合工艺相比,所提出的黏接筋与溶剂辅助键合工艺有效提高了键合效率。该键合方法不仅适用于具有不同宽度尺寸微通道的微流控芯片,还可扩展用于不同材料的硬质聚合物微流控芯片。     

Thermal shock/fatigue evaluation of FGM by AE technique

This study has been carried out to analyze the thermal shock and fatigue characteristics of functionally gradient material (FGM). The thermal shock/fatigue tests were conducted at a specific temperature and fracture patterns were studied by SEM and AE. Also, thermal fracture behavior of plasma-sprayed FGM and conventional coating material (NFGM) was examined by acoustic emission technique under heating and cooling. Furnace cooling and air cooling tests were used to examine the effect of temperature change under various conditions. The conventional and FGM coatings were compared to heat-resistant property and fracture surface of these materials for each temperature history. Based on these results, some critical temperature at the onset of coating failure can be evaluated to characterize the thermal resistance of the materials. It turned out to be that FGM gives higher thermal property compared with NFGM by AE signal and fracture surface analysis.     

刀具涂层技术现状与发展趋势

切削刀具表面涂层技术是近几十年应市场需求发展起来的材料表面改性技术。采用涂层技术可有效提高切削刀具使用寿命,使刀具获得优良的综合机械性能,从而大幅度提高机械加工效率。本文对涂层刀具类别、性能及涂层材料进行了介绍,对常用的涂层方法及一些新的涂层方法进行了阐述,并对涂层技术的国内外现状和发展趋势进行了综合分析与介绍。     

刀具涂层材料的发展

采用涂层技术可有效提高切削刀具的使用寿命,使刀具获得优良的综合机械性能,从而大幅度提高机械加工效率.我国的刀具涂层材料经过多年发展,目前正处于关键时期,充分了解国内外刀具涂层材料的现状及发展趋势,有计划、按步骤地发展刀具涂层材料,对提高我国切削刀具制造水平具有重要意义.     

聚合物合金的摩擦磨损特性的研究

作者采用了聚合物共混技术研制了ＰＣ＋ＰＴＦＥ，ＰＣ＋ＰＴＦＥ＋ＰＰＳ两类聚合物合金，并对这些材料的摩擦学特性及其机理进行了研究。结果表明，ＰＴＦＥ的添加不仅可以提高ＰＣ的耐磨性，而且还可降低其摩擦系数；适量的ＰＰＳ的添加具有减摩抗磨作用。聚全物及其合金的摩擦特性可由粘着摩擦理论解释，其磨损过程主要受粘着，磨粒和疲劳机理控制。     

Sliding bearings used as seismic dampers with composite self-lubricating materials

The scientific basis for the design of self-lubricating self-aligning sliding bearings with reciprocal motion is presented for the first time. The bearings are used as seismic dampers for bridges, industrial and civil buildings, and oil and gas offshore structures; they are superior to known bearings in carrying and damping capacities. An original experimental-calculation method for determining the life of a frictional pendulum sliding bearing used as a seismic damper is elaborated. It implies the use of the dependences for the wear rate presented in generalized variables. A method for estimating the friction coefficient of frictional pendulum bearings is also developed. The outlook for domestic development of an antifriction self-lubricating coating with preset tribological characteristics is analyzed and the present state of the art is discussed. The studies are based on known developments in the field of tribological materials with account for modern advances in nanotribology. The most promising heat-resistant polymers and fillers, as well as combined mixed antifriction fabrics on their basis, are considered.     

A study on development of advanced environmental-resistant materials using metal ion processing

The development of the oxidation, wear and corrosion resistant materials that could be used in severe environmental conditions is needed. The elementary technologies for surface modification include ion implantation and/or thin film coating. Furthermore, in order to develop ion implantation technique to the specimens with three-dimensional shapes, plasma-based ion implantation (PBII) techniques were investigated. As a result, it was found that the ion implantation and/or thin film coating used in this study were/was effective for improving the properties of materials, which include implantations of various kinds of ions into TiAl alloy, TiN films formed on surface of base material and coatings in high-temperature steam. The techniques proposed in this study provide useful information for all of the material systems required to use at elevated temperature. For the practical applications, several results will be presented along with laboratory test results.     

Staining of biological material for the scanning electron microscope

A histochemical technique has been used in scanning electron microscopy to localize specific areas in biological material. The specific contrast introduced by the staining procedure depends on the interaction of complex variables such as the coating material, the accelerating voltage and the use of a primary or secondary electron signal.     

微流控分析芯片的加工技术

综述了微流控分析芯片和加工技术和材质性能,光刻和蚀刻技术常用于加工硅,玻璃和石英芯片。有机聚合物由于品种多,易加工,是代替玻璃和石英的芯片材料。本文总结和讨论了各种芯片材料和它们的加工方法,如光刻,湿法刻蚀,干法刻蚀,模塑法,软刻蚀,热压法,激光切蚀法,LIGA技术和键合技术,引用文献36篇。     

Electroless silver coating of rod-like glass particles

An electroless silver coating of rod-like glass particles was performed and silver glass composite powders were prepared to impart electrical conductivity to these non-conducting glass particles. The low density Ag-coated glass particles may be utilized for manufacturing conducting inorganic materials for electromagnetic interference (EMI) shielding applications and the techniques for controlling the uniform thickness of silver coating can be employed in preparation of biosensor materials. For the surface pretreatment, Sn sensitization was performed and the coating powders were characterized by scanning electron microscopy (SEM), focused ion beam microscopy (FIB), and atomic force microscopy (AFM) along with the surface resistant measurements. In particular, the use of FIB technique for determining directly the Ag-coating thickness was very effective on obtaining the optimum conditions for coating. The surface sensitization and initial silver loading for electroless silver coating could be found and the uniform and smooth silver-coated layer with thickness of 46nm was prepared at 2mol/l of Sn and 20% silver loading.     

Characterization of pyrocarbon coated materials using laboratory based x-ray phase contrast imaging technique

In-line x-ray phase contrast is an emerging x-ray imaging technique that promises to improve the contrast in x-ray imaging process. This technique is most suited for x-ray imaging of soft materials, low atomic number elements such as carbon composite fibers, very thin coatings, etc. We have used this new emerging technique for visualization and characterization of the pyrocarbon coated materials using a combination of microfocus x-ray source and x-ray charge coupled device detector. These studies are important for characterization of coating and optimization of various process parameters during deposition. These experiments will help us to exploit the potential of this technique for studies in other areas of material science such as characterization of carbon fibered structures and detection of cracks and flaws in materials. The characterization of the imaging system and optimization of some process parameters for carbon deposition are also described in detail.     

羟基磷灰石/氧化锆生物活性复合涂层的研究

以钛及合金为基体、HA涂层的复合材料作为植入物应用已很普遍。HA涂层与钛及合金基体的结合强度较低,易出现界面剥落现象;ZrO2具有较好的生物相容性,而且能提高涂层和界面的结合强度,制备HA/ZrO2生物复合涂层已成为国内外学者的研究热点之一。本文综述了HA/ZrO2生物复合涂层的研究进展。