Local damage of HT-materials by laser irradiation in the SEM

By using a pulsed Nd:YAG laser the high temperature materials zirconium oxide, fine grain graphite and silicon nitride were rapidly irradiated (heating thermal shock) and their damage behavior was investigated. The laser beam parameters at sample surface were detected by a laser beam analyzing system and correlated with the local damage mechanisms of the materials as erosion, crack formation and solid-solid phase transformation. For the investigations image analysis, localized x-ray analysis, and the ion beam slope cutting technique were applied. The temperature field in the material was simulated by using temperature dependent material parameters for different laser beam parameters. The results illustrate both the strong influence of the temporal and spatial laser energy profile and the materials properties to the material damage.Dedicated to Professor Dr. rer. nat. Dr. h.c. Hubertus Nickel on the occasion of his 65th birthday     

低反差样品电镜图像衬度的提高

介绍了低反差生物医学样品在其制备，电镜观察以及底片和片的冲洗过程中提高电镜图像衬度的方法。     

聚醚中聚合物分散粒子的形态对体系稳定性和粘度的影响

以苯乙烯和丙烯腈在聚醚中的分散聚合制备了聚合物聚醚，用电镜观察了不同合成条件下分散粒子的形态轨现工艺因素可改变分散粒子的形态，从而影响ＰＯＰ的性质。颗粒聚集是影响体系稳定性和粘度的主要因素。在适宜的合成条件下，可获得稳定的表面光滑的孤立圆球，相应的ＰＯＰ具有低的粘度。     

扫描电镜定量研究Zn-5%Al-0.05%Mg合金的超塑变形机制

用扫描电子显微术研究了微细晶粒的Zn-5%Al-0.05%Mg合金在290℃时于lgσ-igε图中的Ⅱ区或Ⅲ区内拉伸后界面滑动、晶内滑移和扩散蠕变对试样总应变量的分别贡献,获得结果如下:(1)在超塑变形的Ⅱ区内以初始应变速率1.1×10~(-3)S~(-1)拉伸到伸长14%的试样,ε_(bs)/ε_t、ε_(slip)/ε_t和ε_(dIff)/ε_t分别为72.5%、19.8%和7.7%;(2)在非超塑变形的Ⅲ区内以初始应变速率1.1×10~(-1)S~(-1)拉伸到伸长25%的试样,ε_(bs)/ε_t、ε_(slip)/ε_t、和ε_(diff)/ε_t分别为35.8%、48%和16.2%,(3)Zn/Zn晶界的滑动量大于Zn/Al相界的滑动量。     

扫描电镜前级惰性气体保护装置的研制

本文介绍一种扫描电镜用前级惰性气体保护装置，它可用在氩气等惰性气体气氛不装卸易燃，易爆等活性极强的样品，从而实现了活性钙样品的扫描电镜观察与分析。     

丙烯酰胺/2-丙烯酰胺基十六烷磺酸铵无规共聚物的形态结构研究

本工作应用透射电子显微镜研究了丙烯酰胺/2-丙烯酰胺基十六烷磺酸铵无规共聚物(AM/AMC_(16)SNH_4)的形态结构.给出共聚物在水溶液中具有伸展网状结构,并存在一定程度的疏水基因间的缔合作用.是一种在耐盐性和储存稳定性方面有明显改善的新型改性聚丙烯酰胺.     

Synthesis,antifungal activity and in vitro mechanism of novel 1-substituted-5-trifluoromethyl-1H-pyrazole-4-carboxamide derivatives

Inspired by the wide application of amides in plant pathogens, a series of novel 1-substituted-5-trifluoromethyl?1H?pyrazole-4-carboxamide derivatives were designed and synthesized. Bioassay results indicated that some target compounds exhibited excellent and broad-spectrum in vitro and certain in vivo antifungal activities. Among them, the in vitro EC₅₀ values of Y₁₃ against G. zeae, B. dothidea, F. prolifeatum and F. oxysporum were 13.1, 14.4, 13.3 and 21.4 mg/L, respectively. The in vivo protective activity of Y₁₃ against G. zeae at 100 mg/L was 50.65%. SAR analysis revealed that the phenyl on the 1-position of the pyrazole ring was important for this activity. An antifungal mechanism study of Y₁₃ against G. zeae demonstrated that this compound may disrupt the cell membrane of mycelium, thus inhibiting the growth of fungi. These mechanistic study results were inconsistent with those for traditional amides and may provide a novel view for deep study of this series of pyrazole carboxamide derivatives.     

黄原胶分子量的研究

Dintzis曾用经典光散射法测得经90℃、4 mool/L尿素处理3h的黄原胶分子量为2×10~6,不加热的分子量为13×10~6和50×10~6,但未知确切数据.Rinaudo和Milas以相同的方法在l×10~(-3)～l mool/L的氯化钠溶液中测得黄原胶的分子量为2×10~6.Southwick用动态光散射法在4 mol/L尿素中测出其分子量为2.16×10~6.G Holzwarth用透射电镜测出分子量为4×10~6～20×10~6之后,他又通过测定沉降系数和特性粘数,由MFS等式算出黄原胶原始分子量为15×10~6.可见,虽然实验方法和样品不同,但仍可确定其分子量在2×10~650×10~6之间。     

Examination of materials with the mobile thermal microscope ALADIN,a new analytical tool of materials technology

Frequency-modulated optical beams—preferentially laser beams—can excite temperature-modulated thermal waves in a material; their properties are described. Photothermal methods can be used to determine properties of materials at and/or below the surface. The working principle of the thermal microscope ALADIN (advancedlaser-aideddefectinspection innon-destructive testing) is explained; this instrument (developed by Siemens/KWU in collaboration with Phototherm Dr. Petry GmbH/Saarbrücken) provides the user with a flexible, high performance system of modular design. The most important features are mobility, compact design of the sensor and its suitability for use under extremely ambient conditions, e.g. field metallography in power plants. The equipment allows scanning of an area up to 25 mm² with a lateral resolution in the micrometer range. Some examples are given; one of the main applications will be the determination of fatigue or creep damages at metal surfaces.Dedicated to Professor Günther Tölg on the occasion of his 60th birthday     

Dielectric imaging of biological cells

A dielectric technique that can image local permittivity and conductivity has been applied to living biological cells in an aqueous environment. The local permittivity and conductivity were measured between 10 kHz and 10 MHz with a fine probe electrode, which was laterally scanned over cells on a plate electrode. The dielectric images of the cells depended on frequency, indicating dielectric relaxation that is due to interfacial polarization. The low-frequency image (at 10 KHz) in which the cells have high permittivity and low conductivity compared with the medium results from the presence of the plasma membrane with high resistivity. The dielectric image of the cell interior is obtainable at high frequencies (10 MHz), where the plasma membrane is short-circuited.