粒子强度源模型粒子历程的计算和释热量分布

本文利用粒子强度源法来计算煤粉粒子的运动，燃烧过程，并假定煤粉粒子群围绕其中心位置逞正态分布来估算煤粉燃烧热的分布。

太阳高能粒子的电荷态和粒子强度间的相关性

本文发表了在太阳高能粒子事件中,元素氦、碳、氮、氧、氖、镁、硅、硫和铁的离子电荷态的分布。研究结果表明,除氦之外上述元素的电荷态分布的不同离子价的数目是随元素的质量而增大。核子能量在2—3 MeV范围内,这些元素的平均粒子强度相对于碳的平均粒子强度之间的相关性能够用离子价的数目随元素质量的增加来解释,而不能用日冕温度确定的电荷态平衡模型来解释。且得出结论,太阳高能粒子的离子电荷是在太阳耀斑区而不是在星际激波区产生。

炭黑粒子强度测试及其分布影响因素试验研究

采用国家标准使用的专用试验设备对几种常用炭黑粒子强度进行了测定,介绍了专用试验设备的使用及常见故障处理,并对炭黑粒子强度及影响因素进行了分析。结果表明,影响炭黑粒子强度的因素较复杂,未发现明显规律,但为了保证破碎率小于5%,炭黑粒子的压碎强度不得低于22~25g。

提高尿素粒子强度的探讨

通过加强规范操作 ,做好各个环节的调节、控制 ;利用新技术从运输、储藏、包装等方面进行完善改造 ,达到降低尿素粉尘含量 。

用确定性涡方法模拟二维钝体绕流

以离散涡方法为基础,采用粒子强度交换法模拟涡量扩散方程,对粒子场分布产生扭曲变形时采用粒子强度重分配,数值模拟了突然起动圆柱、风攻角为的方形截面和大海带东桥的流场,计算结果与解析解及其他数值方法计算的结果均吻合的很好,数值结果显示确定性涡方法的高精度的特性使其在模拟钝体扰流问题方面具有很大的优势。

桥梁断面雷诺数效应数值模拟研究

针对大海带东桥引桥断面和苏通长江公路大桥主梁断面,基于确定性涡方法进行静三分力系数及Strouhal数(St)雷诺数效应分析,采用粒子强度交换法(PSE)粘性扩散处理。和风洞试验值对比显示,数值计算结果有着合理的可信度。数值计算也显示雷诺数对这两种截面的静三分力系数及St影响不可以忽略;对苏通桥主梁断面在雷诺数在1×105和1×106范围时,St数受雷诺数影响很大,而这个范围内用试验的值来得到实桥的St数是非常困难的。

基于格子涡(VIC)方法的烟雾仿真研究

烟雾仿真一直是计算机图形学研究的难点,基于欧拉法的烟雾仿真存在严重的数值耗散的问题,导致仿真的细节表现不尽如人意,基于纯拉格朗日的方法计算量大实时性难以保证。为了达到较好的效果并且控制计算量提高计算速度,本文使用基于格子涡(VIC)的方法对烟雾进行仿真。在欧拉框架下计算速度场,然后在拉格朗日框架下追踪涡粒子沿迹线的运动。在欧拉框架下使用FFT(快速Fourier变换)快速求解Poisson方程,得到涡量输运方程中从涡量到速度的转换,加快计算速度。对于粘性扩散项中的粒子涡量交换,本文使用粒子强度交换法(PSE)来求解方程。最终实现了对烟雾的仿真,细节效果保留较好,实时性可以接受,验证了该方法的有效性。

圆盘制粒机工艺改进实践

圆盘制粒机是我国炼锑备料系统的主要生产设备之一[1],由于该工艺结构简单、维修方便,受到锑冶炼企业的普遍青睐。文章阐述了锑浮选精矿圆盘制粒机工艺的改进实践,生产实践证明,改进后,粒子成球率、粒子强度等工艺指标均有明显改善。

无线传感器网络自校正定位算法

节点定位是无线传感器网络的重要应用之一,为了抑制实际应用中各种环境因素对无线传感器节点精度的影响,提出了一种基于误差校正的定位算法。通过基于粒子群优化算法的粒子群优化-接收信号强度指示算法(par-ticle swarm optimization-received signal strength indication,简称PSO-RSSI算法)将未知节点收到信标节点一定数量的存在偏差的链路质量指示值进行优化,实现对误差的补偿。将链路质量指示值转化为接收信号强度指示值,从而得到距离。实验结果表明,该算法可提高定位精度,具有普遍应用价值。

Structures and Dynamics of a Two-Dimensional Confined Dusty Plasma System

The influence of the confining potential strength and temperature on the structures and dynamics of a two-dimensional (2D) dusty plasma system is investigated through molecular dynamic (MD) simulation. The circular symmetric confining potential leads to the nonuniform packing of particles, that is, an inner core with a hexagon lattice surrounded by a few outer circular shells. Under the appropriate confining potential and temperature, the particle trajectories on middle shells form a series of concentric and nested hexagons due to tangential movements of particles.Mean square displacement, self-diffusion constant, pair correlation function, and the nearest bond are used to characterize the structural and dynamical properties of the system. With the increase of the confining potential, the radial and tangential movements of particles have different behaviors. With the increase of temperature, the radial and tangential motions strengthen, particle trajectories gradually become disordered, and the system gradually changes from a crystal or liquid state to a gas state.

Experimental and Theoretical Studies of CO2 Absorption Enhancement by Nano-Al203 and Carbon Nanotube Particles

The influence of nano-particles on CO2 absorption was studied experimentally in a stirred thermostatic reactor. Nano-A1203 and carbon nanotube （CNT） particles which showed different hydrophobic properties were chosen for the investigation. The experimental results were compared with that of micron-size activated carbon （AC） and Al2O3 particles. From the results, no enhancement by micron-size A1203 was found, and with the increase of A1203 concentration, the enhancement factor decreased. However, nano-Al203 showed a weak enlaancement tor me COz absorption. AC and CNT particles all intensified the gas-liquid mass transfer effectively, yet the trend of the enhancement factor with stirring speed for the two particles was different. With increasing stirring speed, the enhancement factor of AC particles was decreased, wl＇iereas in CNT suspensions it was increased. The experimental phenomena demonstrated a difference in enhancement mechanism for different size particles. For nano-particles, besides the influence of adsorbability and hydrophobicity, the micro-convection caused by Brownian motion should be also taken into account. Considering the micro-convection effect, a theoretical model was developed to shed light on the absorption enhancement bv nano-oarticles.

Cloud microphysical differences with precipitation intensity in a torrential rainfall event in Sichuan, China

High-resolution data of a torrential rainfall event in Sichuan, China, simulated by the WRF model, were used to analyze the cloud microphysical differences with precipitation intensity. Sixhourly accumulated rainfall was classified into five bins based on rainfall intensity, and the cloud microphysical characteristics and processes in different bins were studied. The results show that：（1） Hydrometeor content differed distinctly among different bins. Mixing ratios of cloud water, rain water, and graupel enhanced significantly and monotonously with increasing rainfall intensity. With increasing precipitation intensity, the monotonous increase in cloud water number concentration was significant. Meanwhile, number concentrations of rain water and graupel increased at first and then decreased or increased slowly in larger rainfall bins.（2） With precipitation intensity increasing, cloud microphysical conversion processes closely related to the production of rainwater, directly（accretion of cloud water by rain（QCLcr） and melting of graupel（QMLgr）） or indirectly（water vapor condensation and accretion of cloud water by graupel）, increased significantly.（3） As the two main sources of rainwater, QCLcrincreased monotonously with increasing precipitation intensity, while QMLgr increased slowly, even tending to cease increasing in larger rainfall bins.

Microstructure and properties of Al-doped ODS steels prepared by wet-milling and SPS methods

In this paper,15Cr-ODS steels containing 0,1 wt%,2 wt%and 3 wt%Al element were fabricated by combining wet-milling and spark plasma sintering(SPS)methods.The microstructure and mechanical properties of ODS steel were investigated by XRD,SEM,TEM,EBSD and tensile tests.The results demonstrate that the Al addition significantly refines the particle precipitates in the Fe-Cr matrix,leading to the obvious refinement in grain size of matrix and the improvement of mechanical properties.The dispersion particles in ODS steels with Al addition are identified as Al2O3 and Y_(2)Ti_(2)O_(7)nanoparticles,which has a heterogeneous size distribution in the range of 5 nm to 300 nm.Increasing Al addition causes an obvious increase in tensile strength and a decline in elongation.The tensile strength and elongation of 15Cr-ODS steel containing 3 wt%Al are 775.3 MPa and 15.1%,respectively.The existence of Al element improves the corrosion resistance of materials.The ODS steel containing 2 wt%Al shows corrosion potential of 0.39 V and passivation current density of 2.61×10^(−3)A/cm^(2)(1.37 V).This work shows that Al-doped ODS steels prepared by wet-milling and SPS methods have a potential application in structural parts for nuclear system.

Simulation Study of Shock Reaction on Porous Material

Direct modeling of porous materials under shock is a complex issue. We investigate such a system via the newly developed material-point method. The effects of shock strength and porosity size are the main concerns. For the same porosity, the effects of mean-void-size are checked. It is found that local turbulence mixing and volume dissipation are two important mechanisms for transformation of kinetic energy to heat. When the porosity is very small, the shocked portion may arrive at a dynamical steady state; the voids in the downstream portion reflect back rarefactive waves and result in slight oscillations of mean density and pressure; for the same value of porosity, a larger mean-void-size makes a higher mean temperature. When the porosity becomes large, hydrodynamic quantities vary with time during the whole shock-loading procedure： after the initial stage, the mean density and pressure decrease, but the temperature increases with a higher rate. The distributions of local density, pressure, temperature and particle-velocity are generally non-Gaussian and vary with time. The changing rates depend on the porosity value, mean-void-size and shock strength. The stronger the loaded shock, the stronger the porosity effects. This work provides a supplement to experiments for the very quick procedures and reveals more fundamental mechanisms in energy and momentum transportation.

Research on the Critical Conditions for Clay Particle Release During Saline Aquifer Freshening Process

Water sensitivity phenomenon occurs during saline aquifer freshening process in seawater intrusion area, and clay particles released in the phenomenon can damage the infiltration capacity of the aquifer. In order to find out the factors and mechanisms for clay particle release, laboratory column infiltration experiments simulating saline aquifer freshening process were designed to measure the critical conditions(critical flow velocity, critical salt concentration and critical ionic strength) and force analysis for clay particle according to DLVO electric double layer theory was employed to illustrate the mechanisms for particle release. The research results showed that critical flow velocity for clay particle release is influenced by salt concentration of injecting solution. When salt concentration of injecting solution is very high, clay particles are not released, indicating that there does not exist a critical flow velocity in this situation. As salt concentration of injecting solution decreases, particles start to be released. The critical salt concentration for clay particle release is 0.052 mol L-1 in our work, which was determined by a constant-flux experiment for stepwise displacement of high concentration Na Cl solution. The critical ionic strength for clay particle release decreases as Ca2+ molar content percentage of the mixed solution of Na Cl and Ca Cl2 increases following the first-order exponential decay equation y = 0.0391e-0.266 x + 0.0015.

七曜阴阳周期性消长特性探讨

文章首次揭示:七曜对地、对人的周年、周日、周月视运动规律;七曜引潮力(万有引力)、电磁波、高能粒子流三大作用对地、对人的阴阳周期性消长律。这将为中医学深入探讨七曜五行生克、五运六气、天时民病提供基础。

非对称核物质中核子动量分布的微观理论计算(英文)

在Extended Brueckner-Hartree-Fock(EBHF)近似下,采用Argonne V18势作为核子-核子相互作用,计算了基态非对称核物质中核子动量的分布。对核子的动量分布对同位旋不对称度的依赖关系进行了描述和讨论。结果表明,在不对称度为零时,质子与中子有着基本相同的动量分布。随着不对称度的增加,在各自的费米面以下,质子动量分布减小而中子动量分布增大。对费米面处的准粒子强度也进行了计算和讨论。本结果较好地满足了两个理论检验标准Migdal-Luttinger theorem和粒子数守恒律。

基于自激振荡的低速气力输送节能试验

目前气力输送设备的开发与应用仍然局限在忽视能耗的粗放型阶段。基于此拟在水平管气力输送系统物料入口上游处安装自由摆动的软翅以产生自激振荡流,实现系统节能降耗的目的。首先,通过试验测量系统的压力损失、最佳输送速度并计算能量损失系数,结果表明:相对于传统输送,自激振荡流能有效降低气力输送系统的最佳输送速度和能量损耗,最大减小量分别为15.2%和25.5%。然后,采用粒子成像测试技术(PIV)测量不同工况下的粒子流型及粒子速度,发现低速输送时自激振荡流可以避免颗粒沉积,增大粒子的轴向和悬浮速度;同时采用快速傅里叶变换(FFT)方法,分析不同工况下的粒子脉动速度,发现自激振荡流作用下的粒子速度脉动强度大于传统输送,揭示了自激振荡流的节能机理。

Compressive strength and abrasion resistance of concrete containing SiO_2 and CuO nanoparticles in different curing media

In the present study,abrasion resistance and compressive strength of concrete specimens containing SiO2 and CuO nanoparticles in different curing media have been investigated.Portland cement was partially replaced by up to 2.0 wt%of SiO2 and CuO nanoparticles and the mechanical properties of the produced specimens were measured.Increasing the nanoparticles content was found to increase the abrasion resistance of the specimens cured in water and saturated limewater,while this condition was not observed for compressive strength in the both curing media.The enhancement of abrasion resistance was higher for the specimens containing SiO2 nanoparticles in both curing media.Since abrasion resistance and compressive strength of the specimens followed a similar regime as the nanoparticles increased for the specimens cured in saturated limewater,some experimental relationships has been presented to correlate these two properties of concrete for this curing medium.On the whole,it has been concluded that the abrasion resistance of concrete does not only depend on the corresponding compressive strength.