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121.
Works of adhesion at the carbon fiber-liquid interface determined using a modified wetting technique
Works of adhesion WSL between aqueous solutions with pH values in the range from 1 to 14 and carbon fibers from different sources, which were additionally treated in an inert atmosphere or in oxygen, were measured by use of a microbalance. These works of adhesion WSL were found to show distinct stepwise dependencies on the pH value. The works of adhesion WSL are attributed to dispersion interactions WSL1 and various acid-base interactions wslab—in the latter case between the acidic and basic surface groups of carbon and the various basic and acidic aqueous solutions. 相似文献
122.
Vinh Q. Nguyen Jas S. Sanghera Brian Cole Pablo Pureza Frederic H. Kung Ishwar D. Aggarwal 《Journal of the American Ceramic Society》2002,85(8):2056-2058
Arsenic sulfide glass optical fibers typically possess extrinsic absorption bands in the infrared wavelength region associated with residual hydrogen and oxygen related impurities, despite using purified precursors. We report a purification process based on the addition of tellurium tetrachloride (TeCl4 ) to the glass. During melting, the chlorine from TeCl4 reacts with the hydrogen impurities to produce volatile products (e.g., HCl) that can be removed by subsequent dynamic distillation. The processing conditions have been modified accordingly to produce optical fibers with significantly reduced loss due to hydrogen sulfide impurity content (1.5 dB/m). 相似文献
123.
Isothermal crystallization of plam oil was studied by means of differential scanning calorimetry (DSC) as well as by nuclear
magnetic resonance spectrometry to monitor its solid fat content (SFC). The temperature of crystallization (Tc) varied from
0 to 30°C, depending on the method used. The plot of %SFC vs. time at 25°C was sigmoidal in shape. However, at lower temperatures,
two consecutive curves were clearly visible. Results from DSC experiments showed the following interesting features. At each
Tc, the crystals produced were of different compositions. From 0 to 8°C, the thermogram showed three peaks, with the first
two peaks (I and II) sharp, and the third (III) rather broad. At elevated temperatures up to 20°C, peak II disappeared totally
while peak III tended to shift toward peak I. Above 20°C, both peaks shifted downward to longer times. Peak I continued to
be broadened, and then suddenly disappeared at Tc above 24°C. The melting thermograms of the crystals obtained above and below
this cut-off point were distinctly different. Kinetic studies on isothermal crystallization based on the data of SFC measurements
showed that the data fit well into the Avrami-Erofeev equation with n=3 over the first 70% of the crystallization. 相似文献
124.
阐述了离心式冷水机且在线监控系统的工作特点以及对监控的要求,说明了在线监控系统的基本配置,关键技术点和功能模块化的软硬件设计。 相似文献
125.
本文介绍一种适合于汽轮发电机组状态监测系统的“看门狗”功能,它可以在很短时间内发现由于外界干扰而导致的计算机的锁死,并马上自动使计算机恢复正常运行。从而提高在线状态监测系统的可靠性。 相似文献
126.
Different fluorination methods were applied to modify the surface properties of carbon fibers. The relationship between the degree of fluorination and the physicochemical properties of carbon fibers was studied using a combination of mechanical tests, elemental analysis (EA), X-ray photoelectron spectrometry (XPS), and X-ray diffraction (XRD). EA and XPS analyses of fluorinated carbon fibers showed that treatment with mixtures of F2/O2 introduced a much higher fluorine concentration than that with F2 only. However, XRD analysis showed that there was no increase in the interlayer distance, due to the mild fluorination condition applied. Consequently, the oxyfluorination was one of the more effective methods to increase surface polarity of carbon fibers, which probably played an important role in improving the tensile properties of the fibers in the epoxy resin system. 相似文献
127.
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129.
The research was conducted to evaluate the effects of cellulose and polyester fibers on the properties of porous asphalt mixes, using the tests of draindown, abrasion, volumetric properties, rutting, and moisture damage. Images of scanning electron microscopy and X-ray computerized tomography were adopted to identify the microstructure of the fiber and inner stone skeleton of porous asphalt. The influence of rutting parameter (G*/sin δ) of asphalt modified by different fibers on the rutting resistance of the mixes was investigated. Based upon MOHR-COULOMB theory, the cohesion and the angle of internal friction of the mixes were derived from both indirect tension and unconfined compression strength. The experimental results indicate that fibers mainly stabilize asphalt binder and thicken asphalt film around aggregates. Furthermore, they result in the improved mechanical strength of porous asphalt mixes at high temperature slightly. From comparison analysis, cellulose fibers appear to perform better than polyester fibers in porous asphalt mixes. 相似文献
130.
在理论上,用源检互换的方法进行折射地震勘探是没有误差的,在某些特殊条件下无法铺设检波器而又必须进行折射地震勘探时它也是唯一的选择,然而,在实际工作中,由于各种因素的影响,其误差是不可忽略的。为此,本文从地震折射运动学的角度对水上地震折射互换法因过河钢丝绳的重量、水的流速和流向、炮点深度等客观因素造成的解释误差进行了分析,揭示了水上地震折射互换法应注意的问题。这对水上地震折射互换法的资料解释进行误差校正提供了理论基础。 相似文献