冲击加载下分步压装装药抗过载响应特性的数值模拟与实验

为研究冲击加载下分步压装装药的响应特性,利用ANSYS/LS-DYNA软件对分步压装含铝炸药大型落锤冲击加载过程进行了数值模拟,得到不同密度分布状态药柱在冲击载荷作用下的应力分布及形变特征。探讨了径向密度差对分步压装装药撞击安全性的影响,并进行了实验验证。结果表明,与传统模压成型药柱不同,冲击加载下分步压装药柱中心区的响应应力大于边缘区,且1/2半径处的炸药微元具有较大的径向流动速率。实验验证结果与模拟结果一致。由于径向密度差的存在,冲击加载下分步压装装药内部应力分布不均,使得炸药颗粒呈现由中心向边缘流动的趋势,进而增加分步压装装药内部"热点"形成的几率。     

压装工艺对CL-20基炸药性能及聚能破甲威力的影响

利用常温成型和热压成型两种工艺制备了典型的CL-20基混合炸药装药,测试了其装药密度、密度均匀性、力学性能、爆速,计算了格尼系数。对Φ50mm标准聚能装药进行了破甲试验。验证了不同压装工艺条件下装填CL-20基炸药装药聚能射流对45号钢靶的侵彻深度和穿孔直径效果。结果表明,与常温成型CL-20基装药相比,热压成型工艺条件时装药的密度提高不小于1.46%,密度均匀性、爆速和格尼系数和破甲能力试验数据均有不同程度的提高,且Φ50mm标准聚能射流对45号钢靶的平均穿深从310mm提高至343mm,平均穿孔直径由18.0mm增至23.5mm。     

PBXN-5装药侵彻混凝土过载力学响应的试验研究

采用弹载小尺寸PBXN-5装药和加速度传感器,并以相同初始速度侵彻两种不同强度混凝土靶板,获得弹体侵彻的过载数据,通过对比分析侵彻前后装药试样的细观结构和外部形状的变化,研究了装药在不同过载条件下的动态力学特性.结果表明,弹内装药着靶后发生了外形镦粗、密度降低的现象,随着过载峰值的提高这一变化更为明显;装药内部出现了沿...     

炸药装药工艺对发射安全性的影响

利用大落锤撞击模拟加载装置，对铸装和压装两种装药条件下的B炸药进行了模拟火炮膛内发射主要加载应力试验，结果表明，在装药其它条件相同的情况下，压装药相对钝感，其发射安全性略优于铸装药。     

改性B炸药装药发射安全性实验研究

通过小型后座模拟装置对空气间隙和石墨层对改性Ｂ炸药装药发射安全性的影响进行了研究,实验结果表明：空气间隙厚度对炸药装药的点火阈值具有很大影响,而石墨层可以减少经中形成的热点,改善炸药装药的发射安全性。     

炮射杀爆弹装药安全失效的影响因素

通过系统分析炮射杀爆弹装药安全失效的影响因素,综合得出炸药装药的安全失效主要是由装药缺陷和使用不当引起的。详细论述了常用炸药的装药缺陷,分析了装药缺陷形成的原因及其对杀爆弹安全失效的影响;杀爆弹装药过程中装药底隙、装药密度和杂质及使用过程中温度、勤务、贮存对安全失效的影响;提出了提高杀爆弹炸药装药安全性的措施。     

球扁药应用于大口径火炮高装填密度发射装药

研究了大弧厚球扁药成型工艺及其在大口径火炮高装填密度装药中的应用可行性。版面上装填试验表明：采用大弧厚球扁药能有效提高装填密度。经钝感处理后,对该药形进行30mm航炮射击试验,当球扁药在装药中的装填比例提高到一定程度时,与制式装药相比,初速增加了2．1％,而最大膛压基本保持不变,点火安全。100H射击试验表明：该药形经钝感处理后,应用于大口径火炮高装填密度是可行的、有效的。     

工艺参数对惰性代料高压熔铸成型质量的影响

为减少熔铸炸药的装药缺陷、提高装药密度，设计制造了一套高压熔铸成型系统，采用与典型TNT基和DNAN基熔铸炸药物理性质相近的惰性代料开展高压熔铸成型试验，研究加载压力、保压时间和加压时机对代料药柱相对密度和装药质量的影响。结果表明，高压熔铸成型过程中，除液相补缩作用被增强外，还存在糊状补缩和固相补缩作用，从而显著减少药柱的装药缺陷，提高相对密度；加载压力应在药柱的三轴压缩屈服强度和三轴压缩抗压强度之间；保压时间应超过药柱的凝固耗时；加压时机的温度应保证模具内壁尚未出现凝固层；加载压力25.45MPa、保压时间60min、加压时机80℃工况下制得的药柱无装药缺陷，相对密度高达99.90%。     

随行装药退火算法的优化设计及数值模拟

为了实现火炮发射过程中的压力平台效应,基于随行装药的思路,建立了固体随行装药内弹道模型和模拟退火算法模型,针对随行装药点火延迟时间和燃速两个关键参数进行优化设计。结果表明,模拟退火算法的优化结果比实验结果更好,在最大膛压不变的条件下,通过提高膛压的充满度系数,可使初速提高100m/s。     

炸药装药在不同应变率响应条件下的安全性研究进展

综述了不同应变率响应条件下炸药装药安全性最新研究进展。通过对炸药装药应用中常用的应变率范围为1~106 s-1的大型落锤实验技术、分离式霍普金森压杆(SHPB)实验技术、一级轻气炮实验技术等进行了评述。分析了不同应变率响应条件下炸药装药安全性实验中存在的问题。根据炸药装药安全性研究的趋势,认为应加强中高应变率响应实验技术的发展,重点完善落锤-霍普金森压杆实验系统的理论及试验体系,提高一级轻气炮实验技术的可控性及重复性。附参考文献61篇。     

基于空泡系数法的小型CO2跨临界热泵热水器最佳充注量计算及实验

自然工质CO2具有良好的环境和热力学性能,在小型系统中得到了越来越广泛的应用.小型系统的充注量决定系统性能优劣,存在着一个最佳值.基于一套小型CO2水源热泵热水器实验台,选用6种典型的空泡系数模型,运用空泡系数法对其最佳充注量进行计算,通过实验研究不同充注量对系统性能的影响,并利用实验结果对各种模型的计算结果进行验证,...     

基于静电势电荷的抗击埃博拉病毒新药物法匹拉韦及其衍生物水溶解度logS值预测

运用分子中的原子理论(AIM),探讨了以法匹拉韦分子羰基氧原子值为目标,测试了不同基组和泛函选择的依赖性。然后用密度泛函理论(DFT B3LYP)和6-31+G(d,p)基组,优化了20种法匹拉韦及其常见衍生物的分子结构,分别得到11号羰基氧的密立根电荷(MUL-O)、自然原子轨道电荷(NBO-O)、何秀巴赫电荷(HIR-O)和静电势电荷(ESP-O)值,发现11号氧原子的ESP-O电荷值与用ACD Lab6.0预测出来的log S值相关性最好,相关系数达0.986;计算了法匹拉韦及其11种未知衍生物的ESP-O电荷值,代入相关最佳线性方程,发现所得结果与ACD Lab6.0预测结果十分接近,最大误差绝对对数值仅为0.08;分子的静电势图也显示法匹拉韦及其甲基法匹拉韦发挥其药理毒理作用可能的部位在电负性强的羰基氧原子上。     

Microstructure design for bone void filler

Bone void fillers are used to fill in the empty space within bone defect. The use of fillers is aiming to reduce the time required for healing the defect. The filler should show the resistance to washout and the ability of adsorption within human body. In the present study, a microstructure design approach is employed to evaluate the performance of bone void filler. The microstructure features, such as the contacts between particles, the size of pores, and their interconnectivity, are considered. The pellets composing of these microstructure features are prepared for in vitro and in vivo evaluations. The type of contacts between resorbable particles plays a key role on washout resistance. The interconnectivity of pores affects significantly on the absorption rate in vivo. Through the control of these microstructure characteristics, the resorbable behavior of bone void filler can be tailored.     

High discharged energy density of nanocomposites filled with double-layered core-shell nanoparticles by reducing space charge polarization

Polymer-based nanocomposite capacitors for energy storage with high discharged energy density and charge-discharge efficiency are of great importance to modern electronic devices and electrical systems. Herein, the energy storage properties are improved by applying double-layered core-shell nanoparticles as fillers. The dopamine was adopted as the outermost layer to improve the dispersibility and compatibility between the fillers and matrix. The high resistance of SiO₂ works as a barrier to limit the movement of space charge over the BaTiO₃ (BT) surface when a high electric field is applied, leading to an enhancement of breakdown strength as well as a decreased space charge polarization, so that an enhancement of discharged energy density and charge-discharge efficiency are achieved. The SiO₂@BT/P(VDF-CTFE) also shows weaker frequency dependence, indicating the reduction of space charge polarization. A possible mechanism of reduced space charge polarization was proposed to explain the effects of SiO₂. This work demonstrates that constructing a core-shell structure with high resistance is an effective way to improve the energy properties of nanocomposite capacitors.     

一种新型电荷调节剂的合成研究

以1,1＇-联二萘酚、乳酸铬为原料合成了一种新型的电荷调节剂,实验结果表明,与对比墨粉相比较,用联萘酚络合铬（Ⅲ）作为制备墨粉的电荷调节剂,可以明显增加墨粉的带电量和显影密度,其灰度、废粉率、耗粉量都有不同程度的下降,预期可以改善制备墨粉的质量。     

Charge Transport in Amorphous Organic Semiconductors: Effects of Disorder,Carrier Density,Traps, and Scatters

In real devices, organic semiconductors are largely amorphous. Because accurate molecular packing in them cannot be obtained, the relationship between the molecular structure and the material properties can be difficult to understand. Nevertheless, knowing the charge transport processes is essential to material and device engineering. In amorphous organic semiconductors, charge transport is often apprehended as a hopping process that can be described using the Marcus or Miller Abrahams equations. The intrinsic disorder and frequently present traps have a great influence on the charge mobility. Carrier density, which would affect the effective density of states and create space charge perturbations, is also one important factor in the charge transport process. Herein, recent advances in the charge transport mechanism in amorphous organic semiconductors are summarized. The influences of disorder, carrier density, traps, and scatters are discussed in detail.     

Ionic Double Layers at the Surface of Magnesium-Doped Aluminum Oxide: Effect on Segregation Properties

A model involving ionic double layers at the surface has been constructed for magnesia-doped sapphire based on earlier models which were developed for cubic halides. The model takes into account the presence of electrostatic potentials, isolated point defects, defect complexes, and special surface sites which can act as sources and sinks for ions. Equations have been set up for the various defect concentrations, and Poisson's equation has been solved numerically to give depth profiles for defects and corresponding electric fields. The calculations suggest that Mg²⁺ ions can segregate both to the free surface and to the space charge region. The effective (or Langmuir) enthalpy of segregation depends not only on the actual binding energies of the dopant ion, but also on other parameters such as the density of special surface sites. Over the temperature range studied, the variation of the calculated surface magnesium concentration with temperature is found to be approximately Arrhenius in nature, as was observed in segregation experiments.     

炸药驱动预制破片轴向抛掷速度规律研究

为解决爆轰产物对轴向预制破片的作用压力从柱状装药中心沿径向逐渐降低,从而导致轴向预制破片抛掷速度沿径向逐渐变小的问题,研究了柱状装药长径比与装药壳体厚度等装药结构参数对轴向预制破片抛掷速度沿径向分布规律的影响,针对某种轴向前置预制破片战斗部,进行了破片轴向抛掷速度沿径向分布规律的试验.结果表明,装药长径比以及装药壳体等装药结构参数对轴向预制破片抛掷速度影响较大,通过装药尺寸、壳体厚度等参数匹配,可以调整轴向预制破片的抛掷速度.     

Studies on the formation of 5-aminosalicylate intercalated Zn-Al layered double hydroxides as a function of Zn/Al molar ratios and synthesis routes

The 5-aminosalicylate intercalated Zn-Al layered double hydroxides (LDHs) with variable Zn/Al molar ratios have been synthesized by both direct coprecipitation (CP) and indirect ion exchange (EX) methods. As-synthesized solids have been characterized by powder X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), UV-visible spectroscopy (UV-Vis), thermal gravimetric analysis (TG) and inductively coupled plasma (ICP) emission spectroscopy, and CHN elemental microanalysis. The results indicate that the supramolecular structure and the loading percentage are highly dependent on the layer charge density and the synthesis routes of the LDHs materials. Four schematic supramolecular structural models of the 5-aminosalicylate intercalates have been proposed, including the staggered dentate-like monolayer arrangement, the vertically adjacent monolayer arrangement, the vertically distant bilayer arrangement, and the vertically adjacent bilayer arrangement. The EX products present highly ordered crystallite than CP ones and the intercalates with higher layer charge density, i.e., the lower Zn/Al ratio, exhibit more ordered crystal structure and higher thermal stability than those with lower layer charge densities.