发射性的

The_n and_ are the neutron proton ratio of the nucleon emission and that of the fragment emission respectively.

这里 n 和 frag分别是核子发射和碎片发射多重性的中子质子比。

By designing the mould to change the propellants model frame, selecting differentmaterials as propellant seal layer agents, studying the preparation technics, we havepreferably solved the PSS seal layer pressurize and combustion disciplinarian problem, andobtained the remarkable increasing burning surface effect.The practical increment ofΓvalue reachs 3.2 upwards conducting closed bomb firings, comparing with 19 holepropellants—the best progressivity burning in the present, whose practical increment ofΓvalue is 1.2, the PSS amplitude ofΓvalue exceeds 2.5 times.

通过药型结构和模具的设计、端面密封材料的选择和制备工艺的研究，较好地解决了PSS发射药的端面密封和燃烧规律控制问题，获得了显著的增面性燃烧效果，密闭爆发器实验中燃气生成猛度的实际增量达到了3.2以上，与目前增面性最好的19孔发射药实际增量的1.2左右相比，增幅超过了2.5倍。

Mechanical properties and combusition characteristics were affected evidently by the solid grain configuration and its character. Mechanical propertiesof the material system could be improved by adopting RDX and proper granularpropellants granularity rank-match. It is favorable to obtain progressivity burning effect byaffiliating increasing burning surface propellant grains. Affiliating fast burning componentthese burning rate regulator in the bond system can quicken burning rate of propellants andimprove burning progressivity.

固体颗粒形态及其性质对力学性能和燃烧性能具有较大的影响，采用RDX与适当颗粒度的固体发射药的粒度级配有利于改善力学性能，加入增面燃烧的发射药颗粒，有利于获得渐增性的燃烧效果，在粘合剂体系中加入速燃组份等燃速调节剂，可加快发射药的燃气生成速率，改善燃烧的渐增性。

Using shape function andclassical interior ballistics theory, the influence relation of the PSS model parameter affectto splitting opportunity, increasing burning surface and interior ballistics characteristicswas researched.The splitting opportunity of PSS appears ahead the academic intending, thereason is that the thickness of outside burning layer is asymmetry, the thinner area splitsearlier, and the thicker area splits later, consequently, the PSS put up progressivity burningeffect. From the practical look, the burning progressivity effect is more profitable than thatincreasing burning surface suddenly.

采用形状函数和经典内弹道理论，研究了PSS发射药的药型参数对分裂时机、燃烧增面性和内弹道性能的影响关系，PSS发射药的分裂时机比理论预计值提前出现，原因是外侧面的燃烧层厚度不均匀，薄的地方先分裂，厚的地方晚分裂，从而表现出了渐增性的燃烧效果，从应用的角度出发，渐增性燃烧的效果比突增的效果要好。

In this paper, nanopowders of rare earth oxides and tungsten were prepared and 0-3 type nano-composit rare earth tungsten thermionic emission materials were fabricated with novel technics. The raw material selection, preparation technic parameter, structure, physical and chemical characteristic, the rare earth distribution and the emission behavior were studied. The influence between the active layer and the thermionic emission performance, rare earth elements diffusion and distribution along depth were investigated in detail. The surplus RE formation and the electron transfer were discussed in theoretically. The thermionic emission current density of the single surplus RE on the active layer was educed. We adopted "liquid-liquid mixing, freeze-drying and two stage-reduction" working step firstly to produce the RE-W nanopowders including La-W powder, Ce-W powder and Y-W powder.

本文采用细化显微组织的新工艺，制备了纳米稀土钨粉末和0-3型纳米复合稀土钨热电子发射材料，探讨研究其原料选择、制备工艺及参数、结构特征、物理和化学特性、稀土分布均匀性、以及热电子发射特性；系统研究了稀土元素的高温扩散情况、高温状态下活性层中稀土的纵向深度分布、以及表面活性物质和活性层厚度对热发射性能的作用；从理论上分析阐释了超额稀土的形成及其电子的传递过程；并从理论上推导了活性层中单个超额稀土的热电子发射电流密度。

Positron Emission Tomography is a kind of atraumatic technology which can detect in itro the metabolic trace of emitted element in human body and can perform 3D imagings.

正电子发射断层成像技术（Positron Emission Tomography，PET）是一种通过体外测量发射性元素在人体内的代谢轨迹，并可进行三维成象的无创检测技术。

The composition designs and performances of LOVA propellants are investigated on the basis of thorough analysis of constraints of caseless gun bullet system to propellant performance under the program of caseless ammunitions.

论文选择无壳枪弹为应用背景，分析了该系统对发射药性能的约束条件，进行了低易损性发射药的基础配方设计和性能研究。

Excitation functions of neutron, proton and α particle emission prior to scission measured in the reactions 28 Si+ 164,167,170 Er→ 192,195,198 Pb are studied using an extensive fission diffusion model and it is found that the model can well describe the trend of particle multiplicities of Pb isotopes measured experimentally as a function of the bombarding energy,which indicates the existence of isotope effects in prescission particle emission.

用推广的裂变扩散模型研究了2 8Si+16 4，16 7，170 Er→192 ，195，198Pb反应中测量的断前中子、质子和α粒子多重性的激发函数。发现扩散模型能很好地拟合这些轻粒子多重性随裂变系统激发能和Pb同位素的变化趋势。表明断前粒子发射存在一个同位素效应。进而在一个考虑了裂变过程中摩擦效应的统计模型的框架内，在In和Er这两个元素的同位素链中，考察了同位素效应与裂变碎片质量不对称性和裂变系统尺度的关系。计算结果表明：同位素效应的存在不依赖于裂变系统的大小和不对称性。此外，当裂变系统具有高的中质比时，轻带电粒子发射将不再敏感于裂变延迟时间的长短，而中子发射则非常敏感。

NASA successfully demonstrated an alternate system for future astronauts. The launch of the Max Launch Abort System, or MLAS, took place on July 8, 2009, at 6:26 a.m. at NASA's Wallops Flight Facility, Wallops Island, Va.

2009.7.8早晨6：26，弗吉尼亚州的瓦勒普岛、美国宇航局的瓦洛普飞行中心，NASA成功演示了用于未来太空发射任务的替代性系统——最大发射失败救援系统，简称MLAS。

The problem considered in this paper contains absorbing-emitting medium, absorption and emission of radiation not only exist on boundary of the system, but exist in the whole space fulled of medium, variation of temperature, pressure, density, compusure and property with coordinates must be considered in computation, so computation in this paper is based on three dimensional flow field.

本文所计算的问题包含吸收-发射性介质，能量的吸收和发射不仅发生在系统的边界上，而且还发生在充满介质的全部空间，在计算中要考虑介质中各点的温度、压力、浓度、成份以及物性在空间上的变化，因此本文的计算是根据三维流场计算的数据进行的。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失