天然气吸附剂的开发及其储气性能的研究——Ⅰ-吸附剂制备与体积法评定吸附剂的储气性能

报道了天然气吸附剂的基本制备技术,并采用体积法评定了吸附剂的储气性能。结果表明,采用作者开发的吸附剂制备工艺可获得性能优良的天然气吸附剂。以木质素为原料制备的粉状吸附剂,其比表面积可达２９１２ｍ２／ｇ,微孔体积可达１－４８ｃｍ３／ｇ,平均孔径为１－４８ｎｍ ,堆密度为０－３０ｇ／ｃｍ３ 。在６－０ＭＰａ、２５ ℃下,天然气的吸附储存量可达到１４０Ｖ／Ｖ。天然气吸附剂的储气性能与其比表面、微孔数量、填充密度等参数有重要关系     

Angular structure of laser radiation in a Markov binary mixture

Laser-radiation transfer in a Markov binary mixture is compared to transfer in an equivalent homogeneous medium. Within the framework of a small-angle approximation a system of equations that describe the angular moments of the second order (angular dispersion) for a laser beam and the equation for laser-beam intensity is obtained. The results of the calculations show a significant effect of the stochastic nature of the medium on the intensity and the angular structure of the laser beam. Deceased Institute of Applied Optics, National Academy of Sciences of Belarus, 11, Belynitskii-Birulya St., Mogilev, 272793. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 1, pp. 36–42, January–February, 1999.     

How to measure energy dissipation in dynamic mode atomic force microscopy

When studying a mechanical system like an atomic force microscope (AFM) in dynamic mode it is intuitive and instructive to analyse the forces involved in tip–sample interaction. A different but complementary approach is based on analysing the energy that is dissipated when the tip periodically interacts with the sample surface. This method does not require solving the differential equation of motion for the oscillating cantilever, but is based entirely on the analysis of the energy flow in and out of the dynamic system. Therefore the problem of finding a realistic model to describe the tip–sample interaction in terms of non-linear force–distance dependencies and damping effects is omitted. Instead, it is possible to determine the energy dissipated by the tip–sample interaction directly by measuring such quantities as oscillation amplitude, frequency, phase shift and drive amplitude. The method proved to be important when interpreting phase data obtained in tapping mode, but is also applicable to a variety of scanning probe microscopes operating in different dynamic modes. Additional electronics were designed to allow a direct mapping of local energy dissipation while scanning a sample surface. By applying this technique to the cross-section of a polymer blend a material specific contrast was observed.     

Crystallization behavior and thermal properties of blends of poly(3-hydroxybutyate-co-3-valerate) and poly(1,2-propandiolcarbonate)

Crystallization behavior of blends of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(1,2-propandiolcarbonate) (PR(CO₂)) has been investigated by polarized light microscopy (PLM). The spherulite growth rates (SGR) of all blends were faster than that of pure PHBV, and the spherulite growth rates of PHBV in the PHBV/PR(CO₂) blends reduced with increasing PR(CO₂) weight fraction. There are two melting peaks in both the pure PHBV and the PHBV/PR(CO₂) blends. The melting peak of PHBV/PR(CO₂) blends was reduced by lower temperature about 20K as compared to PHBV and the higher temperature melting peak was increased by about 10K in the blends.     

Non-linearity parameter B/A of binary liquid mixtures at elevated pressures

When sound waves of high amplitude propagate, several non-linear effects occur. Ultrasonic studies in liquid mixtures provide valuable information about structure and interaction in such systems. The present investigation comprises of theoretical evaluation of the acoustic non-linearity parameter B/A of four binary liquid mixtures using Tong and Dong equation at high pressures and T=303.15 K. Thermodynamic method has also been used to calculate the non-linearity parameter after making certain approximations.     

Electron impact single ionization of copper

Electron impact single ionization cross sections of copper have been calculated in the binary encounter approximation using accurate expression for σ _ΔE as given by Vriens and Hartree-Fock momentum distribution for the target electron. The BEA calculation based on the usual procedure does not show satisfactory agreement with experiment in this case but a striking modification is found to be successful in explaining the experimental observations. The discrepancy is linked with the ionization of the 3d ¹⁰ electrons and probably effective single ionization does not take place from 3d shell of copper leading to smaller values of experimental cross sections.     

吸热型碳氢燃料的热氧化安定性研究

采用静态法测定了自行研制的吸热型碳氢燃料ZH-100在加强氧化条件下的热氧化安定性能，用红外光谱检测ZH-100热氧化前后官能团的变化．结果表明，在160℃下加强氧化5h后燃料组分中除了原有的-CH3和-CH2-官能团外，还明显检出了羟基、羰基和碳碳双键3种官能团，红外分析结果很好地解释了燃料经加强氧化后颜色发生变化的原因．通过碘量比色法对氧化过程中生成的过氧化物进行定量分析，解释了燃料的热氧化反应机理，评价了3种抗氧化剂的效果．结果显示合适的抗氧化剂可以使燃料的热氧化安定性有一定程度的提高．     

Mechanistic Investigation into the Unique Orientation Textures of Poly(vinylidene fluoride) in Blends with Nylon 11

Self‐seeded crystallization experiments were carried out to detect the mechanism of the unique orientation behavior of poly(vinylidene fluoride) (PVDF) in oriented PVDF/nylon 11 blends. It was found that primary nuclei have no effects on the final orientation textures adopted by PVDF. The results show that the PVDF crystal orientation in the oriented blends is determined in the early stage of crystal growth, thus a trans crystallization mechanism is preferred.

Isothermal crystallization kinetics for the self‐seeded and non‐self‐seeded crystallization at 145 °C.     

Parallel Breakup of Polymer Drops under Simple Shear

The deformation and breakup of a single polycarbonate drop in a polyethylene matrix is studied at high temperatures under simple shear flow using a transparent Couette device. We observed “parallel breakup” where the drop breaks after being stretched into a thin sheet parallel to the flow. The breakup occurs at a viscosity ratio greater than 3.5. Deborah number and a stress ratio incorporating elastic moduli can characterize the “parallel breakup”.

Deformation and breakup of a polycarbonate drop in a polyethylene matrix.     

沟渠内杨木三合板架空燃烧的火灾行为的研究

建立了缩尺寸沟渠火灾试验模型,测量了沟渠以及平台入口附近的温度分布,研究了沟渠内杨木三合板架空燃烧的位置和沟渠的倾斜角度对火蔓延行为的影响,分析了火焰传播特征和火蔓延速率.试验结果表明:在沟渠效应和烟囱效应的综合作用下,火焰先从杨木三合板与沟渠底板之间的狭长空间传播到沟渠顶部,在入口处形成喷射状火焰;狭长空间内的温度先...