鸡血石的矿物成分

对昌化石和巴林石的化学分析、粉晶X衍射分析、差热分析、红外光谱分析、显微镜和扫描电镜鉴定证实,鸡血石的矿物成分除辰砂外主要是地开石,而不是叶蜡石或高岭石,此外有少量明矾石、石英、黄铁矿等杂质矿物。     

Stationary Phase 5. Evaluation of Stationary Phases for HPLC of Explosives

The retentions of 11 explosives on two commercially RP-18 and Si 100 stationary phases and one prepared 3-[9′-(10′-methylanthryl)]- propylsilane stationary phase (MAPS-phase) were examined by modified mobile phases. The evaluation of these three stationary phases results as follows:

• (1) Most explosives were effectively separated on a column of MAPS-phase not only with methanol/water (75/25-85/15) as mobile phase but also with n-hexane/dichloromethane (75/25) as mobile phase.
• (2) Few explosives were effectively separated on a column of RP-18 with methanol/water (75/25-85/15) as mobile phase.
• (3) The separation of most explosives on Si 100 was achieved only under normal phase condition such as n-hexane/dichloromethane (75/25) as mobile phase.

     

Inferring the degradation of pultruded composites from dynamic nonlinear resonance measurements

The Chemical resistance of pultruded polyester composites to various chemical immersion solutions is investigated as a function of the exposure time, and the observations from static tests are compared with the results from nonlinear dynamic vibration experiments. The mechanical properties were measured according to ASTM standards, both in flexural and tensile tests. Barcol hardness and sorption measurements provide complemntary information. In addition, a novel nondestructive (NDE) method, called Single Mode Nonlinear Resonance Acoustic Spectroscopy (SIMONRAS), was applied to measure the linear and nonlinear dynamical properties of the samples as a funtion of exposure time. This new NDE method focuses on the strain amplitude dependence of the resonance frequency while driving a sample at relatively low excitation levels. The obtained relative frequency shift is a measure of the internal microstructural properties of the material. The correlation between this nonlinearity parameter and the mechanical properties is extremely good, which implies that the SIMONRAS technique can be applied to predict the chemo‐mechanical degradation of composites in a nondestructive manner.     

An infrared analysis method to determine the aromatic carbon content of mineral lubricant base oils based on correlation with carbon-13 NMR aromaticities

A widely used method to determine base oil aromaticity was introduced by G. Brandes in 1956 and is based on a correlation between the infrared aromatic absorption band at 1610 cm⁻¹ and the aromaticity determined by the n-d-M method. Accurate and absolute aromaticities can be measured by carbon-13 NMR but, infortunately, this technique is not suitable for routine analysis. The aromaticities measured by NMR are almost invariably significantly lower than those obtained by Brandes' method. In this study, the areas of the infrared aromatic bands at 1610 and 815 cm⁻¹ of over 70 base oils with aromaticities ranging from 1–16% were correlated by multilinear regression with their carbon-13 NMR aromaticities. An equation to calculate the aromaticity from infrared absorptions was derived. These aromaticities show an excellent match with carbon-13 NMR data. This new infrared method can be applied as a fast and convenient base-oil quality control tool.