Initiation of detonation in hydrogen—Air mixture by explosion of a spherical TNT charge

Direct initiation of detonation by explosion of a TNT charge in a hydrogen—air mixture is considered. The critical mass of initiating charge is determined numerically using a finite-difference method based on the Godunov scheme, taking into account the real chemical kinetics of combustion of hydrogen in air and the real equation of state for gaseous detonation products of TNT. The applicability of the equation of state of a perfect gas to the detonation products of TNT is considered. The effective value of the exponent of Poisson's adiabat is determined.Moscow. Translated from Fizika Goreniya i Vzryva, Vol. 31, No. 2, pp. 91–95, March–April, 1995.     

Explosion of a cylindrical charge above a rigid surface

We investigated the explosion of a cylindrical charge, which lies on a rigid surface or is positioned at some height above it. The explosion is modeled by the jump between the background and the region occupied by gas at a high pressure, density, and temperature. In an analogous formulation, the explosion from the Tunguska meteorite impact [1–4] was modeled by spherical and cylindrical explosive waves which consider the gravitational back pressure. Explosions from charges with nontraditional shapes have been studied [5–8]. Reflections of an explosive wave from a point charge from a rigid surface have been examined [9–10]. A more complete review of investigations on the spatial effects of forming propagating explosive waves can be found in [11].Moscow. Translated from Fizika Goreniya i Vzryva, Vol. 27, No. 6, pp. 131–134, November–December, 1991     

Mechanical properties and structure of a nanoporous sodium borosilicate glass

The nanohardness (H) and microhardness (H _M) of sodium borosilicate glasses with and without nanopores were studied. From nanoindentation measurements, along with the hardness H, the Young’s modulus E was derived. While both H and H _M varied between ∼10 GPa and ∼7 GPa for the bulk glass, the values for nanoporous specimens were one order of magnitude lower at about 0.5 GPa. The Young’s moduli were found to be ∼82 GPa and ∼5 GPa for bulk and porous glasses, respectively. Cracks and pileups were observed, respectively, arising from microindents and nanoindents in the bulk glass, whereas none of them could be detected in the nanoporous material. The molecular structures of both glasses studied by X-ray diffraction are similar. The text was submitted by the authors in English.     

A three-dimensional thermal and electromagnetic model of whole limbheating with a MAPA

Previous studies by the authors have shown that if properly implemented, the Pennes assumptions can be applied to quantify bioheat transfer during extremity heating. Given its relative numerical simplicity and its ability to predict temperatures in thermoregulated tissue, the Pennes model of bioheat transfer was utilized in a three-dimensional thermal model of limb heating. While the arterial blood temperature was assumed to be radially uniform within a cross section of the limb, axial gradients in the arterial and venous blood temperatures were computed with this three-dimensional model. A realistically shaped, three-dimensional finite element model of a tumor-bearing human lower leg was constructed and was "attached" mathematically to the whole body thermal model of man described in previous studies by the authors. The central as well as local thermoregulatory feedback control mechanisms which determine blood perfusion to the various tissues and rate of evaporation by sweating were input into the limb model. In addition, the temperature of the arterial blood which feeds into the most proximal section of the lower leg was computed by the whole body thermal model. The variations in the shape of the tissues which comprise the limb were obtained from computerized tomography scans. Axial variations in the energy deposition patterns along the length of the limb exposed to a miniannular phased array (MAPA) applicator were also input into this model of limb heating. Results indicate that proper positioning of the limb relative to the MAPA is a significant factor in determining the effectiveness of the treatment. A patient-specific hyperthermia protocol can be designed using this coupled electromagnetic and thermal model.     

激光熔区中应力缓解的X射线衍射法测定

AISI 304奥氏体不锈钢表面经激光熔化处理,引入一个大的张应力,它可用注Ne的方法使其缓解本文介绍测量0.1μm薄层应力变化的原理和技术,由测得的应力分布曲线证明了注Ne缓解表面张应力的效果     

Spin dynamics and implications for superconductivity: some problems with thed-wave scenario

We review the spin dynamics of the normal state of the cuprates with special emphasis on neutron data in both the YBa₂Cu₃O_7– and La_2–x Sr _x CuO₄ systems. When realistic models of the Fermi surface shapes are incorporated, along with a moderate degree of spin fluctuations, we find good semiquantitative agreement with experiment for both cuprates. Building on the success of this Fermi-liquid-based scheme, we explore the implications ford-wave pairing from a number of vantage points. We conclude that our present experimental and theoretical understanding is inadequate to confirm or refute thed-wave scenario.     

新能源分比例渗透下基于博弈的多主体效益综合评估方法

“双碳”目标下新能源大规模发展,新能源的发展给各能源主体带来了影响,如何量化评估新能源渗透给能源主体带来的影响成为研究重点。首先,基于改进的K-means算法构建基于典型场景集的新能源出力模型;然后,从源-网-荷-储出发,构建火力发电商、电网、用户、储能运营商的决策优化模型;其次,构建考虑新能源渗透的多能源主体效益评估模型;最后,进行算例分析,算例结果验证了模型的有效性。     

Stress relaxation in InGaAsP/InP heterostructures for 1064-nm laser radiation converters

Technical Physics Letters - Specific features of mechanical-stress relaxation in InGaAsP/InP heterostructures for 1064 nm laser radiation converters have been studied. It is established that stress...