水下爆炸冲击波能的数值计算

在进行炸药配方设计时,冲击波能的计算是非常重要的.理想炸药水下爆炸的冲击波能流密度符合爆炸相似率.提出了方程中系数ζ和γ的计算公式,参数ζ和γ可以通过炸药的爆热、爆压和密度等近似计算.根据文献值拟合冲击波能随铝氧比的变化公式,可用来计算非理想炸药的冲击波能.计算结果与试验数据吻合较好.     

RDX基铝纤维炸药与铝粉炸药水下爆炸性能比较

为了评估含铝炸药的综合性能,将铝粉用铝纤维代替,与RDX均匀混合压制得到铝纤维炸药,分别对铝纤维炸药、铝粉炸药、RDX进行水下爆炸实验,测量70 cm、90 cm、120 cm、150 cm处冲击波压力时程,获得三种炸药在不同位置处的冲击波压力峰值、冲量、比冲击波能、气泡脉动周期、比气泡能等参数,研究表明:在压力时程的有效持续时间内,铝纤维反应速率低于铝粉,铝纤维破碎消耗部分能量,导致铝纤维炸药的压力峰值、冲量、比冲击波能低于铝粉炸药。铝纤维的比表面积小,未被氧化的铝含量比铝粉高,且第一次气泡脉动周期较长,使得铝纤维与铝粉参加反应的程度相当,铝纤维炸药的比气泡能略高于铝粉炸药,使得铝纤维炸药的总能量与铝粉炸药相当。     

高能温压炸药标准物质四项爆轰参数不确定度的评定

高能温压炸药标准物质不确定度的大小主要由定值装置、标准物质及多家定值引入,本文利用测量不确定度评定方法对高能温压炸药标准物质进行了不确定度评定,给出了标准物质的温压性能参数不确定度的数值,并进行了验证。     

爆破战斗部水中兵器爆炸威力评定方法研究

为确定爆破战斗部水中兵器爆炸威力评定方法,正确反映水中兵器作战性能和毁伤目标能力,基于某舰船缩比模型的海上爆炸试验,以标准TNT药球作为爆源,根据试验实测的冲击波压力数据和气泡脉动数据,分析对比目前爆破战斗部水中兵器爆炸威力评价的常用方法,即冲击波压力峰值推算法和战斗部爆炸相对能量评估方法,计算装药的TNT当量。结果表明:战斗部爆炸相对能量评估方法具有更高精度,可作为爆破战斗部水中兵器爆炸威力评定的通用方法。     

装药壳体对含铝炸药水下爆炸性能影响研究

针对某含铝炸药,分别在6 mm钢壳、硬铝壳、PVC壳及裸药柱形装药条件下进行水下爆炸实验,测量3 m,5 m,7 m处冲击波压力时程曲线,获得不同装药条件下冲击波的峰值、冲量、能量及气泡脉动周期和气泡能等参数。利用AUTODYN-2D程序,对带壳装药含铝炸药水下爆炸过程进行数值模拟,通过与实验测量结果对比,验证数值仿真方法和结果的准确性。在此基础上,结合量纲分析与数值模拟方法研究填装比对冲击波波形、压力峰值及气泡脉动周期的影响规律。研究表明：填装较小时,冲击波压力峰值与冲击波能均增大;填装较大时,压力峰值与冲击波能均减小;气泡脉动周期随填装比的增加而减小;在钢壳装药下,最优填装比为1.45。有限元模型与计算结论可为水中兵器设计提供一定参考。     

水中冲击波传播规律及在水压爆破中的应用

炸药包在一定水深爆炸时，形成水中冲击波的运劝，同时形成水中气泡。本文通过分析炸药在水中爆轰后形成冲击波和气泡等现象，研究水中冲击波的传播和气泡上升的规律，并应用在水压爆破中，确定药包重量、入水深度、注水高度等参数的数值。     

水胶炸药不同交联时间水下爆炸能量的研究

为了研究化学发泡剂对水胶炸药水下爆炸能量的影响,制备了交联时间分别为0.5、1.0、3.0、24.0、72.0 h和168.0 h的水胶炸药;在相同的试验条件下,采用水下爆炸法分别测试不同交联时间下水胶炸药水下爆炸的比冲击波能、比气泡能以及总能量,并与2^#岩石乳化炸药水下爆炸总能量进行对比。结果表明,化学发泡剂对水胶炸药水下爆炸能量有较大的影响,在一定的交联时间范围内,随着交联时间的延长,水胶炸药的水下爆炸能量持续增加,当交联时间为72.0 h左右时,水胶炸药的水下爆炸能量达到最大;此后,若再延长交联时间,水胶炸药的水下爆炸能量呈下降趋势。交联时间为1.0 h时,水胶炸药的水下爆炸总能量与2^#岩石乳化炸药的水下爆炸总能量相当。     

硼含量对含铝炸药水下爆炸能量的影响

将铝硼混合添加到含铝炸药(配方体系为Al/B/AP/RDX/wax)中,采用水下爆炸法,研究硼含量对含铝炸药水下爆炸能量的影响。结果表明,水下爆炸中,随着硼含量的增加,炸药的冲击波能降低,气泡能先增加、后逐渐减小;当硼质量分数为10%时,炸药水下爆炸总能量达到最大值5.942 MJ/kg,比含铝样品提高5%,其中气泡能为4.999 MJ/kg,比含铝样品提高7%,是TNT的2.2倍。在含铝炸药中添加少量的硼粉,可以提高炸药的水下爆炸能量水平。     

不同组分温压炸药的爆炸冲击波特性

为了更好地运用炸药爆炸的毁伤能力,采用相关实验手段对不同组分温压炸药的冲击波超压、正压作用时间及冲量等反应爆炸冲击波特性的参数进行了研究,并将测得的实验结果与TNT的爆炸冲击波特性进行了对比分析。结果表明,两种温压炸药W-1、W-2的爆炸性能均强于TNT炸药,且由于固液混合相温压炸药W-2中各组分混合得更为均匀,其爆炸性能强于固相温压炸药W-1,可为进一步研究温压炸药毁伤效应提供参考。     

不同组分温压炸药的爆炸冲击波特性

为了更好地运用炸药爆炸的毁伤能力,采用相关实验手段对不同组分温压炸药的冲击波超压、正压作用时间及冲量等反应爆炸冲击波特性的参数进行了研究,并将测得的实验结果与TNT的爆炸冲击波特性进行了对比分析。结果表明,两种温压炸药W-1、W-2的爆炸性能均强于TNT炸药,且由于固液混合相温压炸药W-2中各组分混合得更为均匀,其爆炸性能强于固相温压炸药W-1,可为进一步研究温压炸药毁伤效应提供参考。     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Assessment of intakes of mixtures of radionuclides

Australia has several uranium mines and a large number of mineral sand mines, with associated processing facilities. Exposures resulting from these mining and processing operations usually involve intakes of mixtures of radionuclides. This work describes the development of a suite of first order, linear compartment models, based on the ICRP Publication 66 respiratory tract model, and an analytical solution to the decay equations, for assessing the consequences of such intakes. The computer programs based on these models directly compute excretion, organ retention and organ and whole-body doses for intakes of either single radionuclides or any mixture of radionuclides belonging to the same radioactive decay chain. The intake can be via inhalation, ingestion or injection, and can be acute, chronic or of limited duration. The starting concentration and degree of secular (dis)equilibrium can be specified for each radionuclide. No assumptions need to be made about the relative magnitudes of the radioactive half-lives of the different nuclides.     

卧式金属罐容量的测量结果不确定度

本文根据多年的实践检定经验 ,参照JJF1 0 59- 1 999《测量不确定度评定与表示》以及《测量不确定度表达 1 0讲》 ,对卧式金属罐容量的测量结果不确定度进行了评定。     

盐酸浓度不确定度的评估

通过对盐酸浓度标定的过程分析，找出影响结果的各个分量，进行不确定度的评定，按照计量技术规范给出标准的表示法。     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Analysis of anisotropy of properties on the basis of studies of texture of coarse-grained ingots of thermoelectric materials

An analysis of anisotropy of the properties of a Bi₂Se_0.3Te_2.7 solid solution was carried out using construction of demonstrative surfaces for thermoelectric effectiveness and thermal expansion coefficients. It is shown that the texture is an important factor forming anisotropy of properties and technological fitness of ingots for manufacturing modules. Anisotropy of properties based on the studies of the ingot textures obtained using the float-zone method and Bridgman method (growing thermoelectric plates in a flat cavity) was studied.