关于进入工业火焰的煤粉颗粒温升速率的探讨

从传热角度对煤粉微粒进入高温环境的温度变化进行了初探,对沉降试验炉和煤粉炉内的煤颗粒与环境的换热及有关试验进行对照比较,其结果表明热传导是微粒与外界换热的主要形式。针对流化床锅炉的特点及大小不同的煤颗粒的温升速率进行了探讨。     

Wettability of micron/submicron-sized particles in oilsands bitumen characterized by suspension turbidity

Determination of the wettability of micron/sub-micron sized particles remains a great challenge. The present work proposes a new approach to evaluate the particle wettability by measuring the turbidity of particle suspension. The fine solid samples with varying wettability were prepared by hydrothermal treatment of oilsands bitumen at different temperatures. The turbidity of particle-in-toluene suspension was determined and correlated to the particle surface chemical composition, i.e., C/(Al?+?Si). A good linear relationship was observed between particle wettability and suspension turbidity. The results suggest suspension turbidity can be used to characterize the wettability of organically-modified fine solids in oilsands bitumen.     

Catalysis by nanoscale gold (Au/MOx): B. Reaction mechanisms of low temperature CO oxidation reactions

Here, in Part B of this Series, we take a critical look at the reaction mechanisms of low temperature CO oxidation reactions over nanoscale gold, including adsorption, surface reaction, and desorption of key substrates, viz., CO and O₂. Based on a concerted analysis of reactivity data of Au nanoparticles, physicochemical surface characterization, and theoretical first principles calculations, we conclusively prove that out of the 2 most commonly invoked reaction mechanisms, gold-only vs. gold-assisted, the latter is the only mechanism operative for supported gold particles in the quantum size range of 2–5?nm. The Au-MO_x support perimeter interface is a structural motif that is very rich in small metallic particles, and extremely low-coordinated Au sites (with N ～4–5), and some in presence of atomic bonding with Zn atoms. There is both charge and species transfer at this perimeter interface, which also provides highly active sites for adsorption of CO and O₂.     

工业装置渣油加氢失活催化剂上的金属赋存状态研究

以工业固定床渣油加氢失活催化剂（失活剂）为研究对象,依次采用正庚烷、甲苯对其进行索氏抽提,通过对失活催化剂上金属含量、形态及分布进行分析表征,发现金属沉积量沿着物流方向呈现降低趋势。通过Raman光谱、XPS分析表征发现,渣油加氢失活剂表面沥青质类物质含量很低。渣油加氢处理催化剂的活性相主要有3种：MoS2相、NiMoS相或CoMoS相。沉积的焦炭和金属使得催化剂暴露在外表面的活性相数量非常少。     

分子结构、相容性和流变性对抗冲共聚聚丙烯中分散颗粒形态的影响

分散颗粒形态对抗冲共聚聚丙烯的冲击强度有较大影响。综述了影响分散颗粒形态的因素,包括等规聚丙烯的分子结构和丙烯均聚工艺、等规聚丙烯和乙丙橡胶之间的相容性、长丙烯链段乙烯-丙烯嵌段共聚物的分子结构及其对等规聚丙烯和乙丙橡胶之间相容性的增强作用、长乙烯链段乙烯-丙烯嵌段共聚物的分子结构及其对乙丙橡胶流变性的干扰等。调整共聚反应的乙烯与烯烃摩尔比可以有效改善抗冲共聚聚丙烯分散颗粒的形态。     

配入低阶煤对制得气化焦气化特性的影响

从7种煤样中筛选出3种制焦配煤,利用高温热解实验装置在不同热解温度条件下制备3种煤焦,分析了温度对热解产物分布的影响规律,测定了煤焦的比表面积、孔体积及孔径分布特征,并揭示了煤焦孔隙特性及煤种与煤焦的CO2气化反应活性的相互关系。结果表明,随热解温度的升高,3种煤焦收率下降,同等温度条件下,配煤CY/QM制得的煤焦收率最低;在制焦终温低于1 150℃时,煤焦的比表面积及孔体积随制焦温度的提高而增大,气化活性亦随之增加,不同配煤所制得的煤焦反应性大小顺序为:CY/QMCY/QM/JMCY/GSJM;而在制焦温度达到1 150℃之后,煤焦部分孔结构坍塌,其气化活性不再明显增加,3种配煤所制得煤焦的反应性亦相差不大。     

落锤试验撞击粒状HMX炸药变形及点火过程数值模拟（英）

利用AUTODYN软件对落锤撞击粒状HMX炸药过程进行二维数值模拟.基于应力和塑性功的计算值,通过塑性功转化热能的原理,估算了颗粒中产生的温升.样品HMX颗粒为圆形几何形状,假设颗粒具有弹塑性变形特性.颗粒堆放形式有规则排布和不规则排布两种情形.通过设定的落高和由自由落体公式计算出落锤的初始速度.针对落高分别为33,40,50,60 cm的情况,及样品颗粒材料不同屈服应力值(0.26,0.13 GPa)进行计算,得到落锤撞击颗粒时的温升变化.结果表明,规则排布产生温度较低(37.2℃),而不规则排布产生温度较高(142.9℃).在不规则排布当中,颗粒的局部塑性变形功可以导致较高的温升,从而引起颗粒点火.同时考虑到HMX的屈服应力值的不确定性,取较小屈服应力值(0.13 GPa)进行温升计算,而其他计算条件相同,得到的温升值仅为83.2℃,比0.26 GPa时低59.7℃.     

Passive Target Tracking in Non-cooperative Radar System Based on Particle Filtering

We propose a target tracking method based on particle filtering（PF） to solve the nonlinear non-Gaussian targettracking problem in the bistatic radar systems using external radiation sources. Traditional nonlinear state estimation method is extended Kalman filtering （EKF）, which is to do the first level Taylor series extension. It will cause an inaccuracy or even a scatter estimation result on condition that there is either a highly nonlinear target or a large noise square-error. Besides, Kalman filtering is the optimal resolution under a Gaussian noise assumption, and is not suitable to the nonGaussian condition. PF is a sort of statistic filtering based on Monte Carlo simulation that is using some random samples （particles） to simulate the posterior probability density of system random variables. This method can be used in any nonlinear random system. It can be concluded through simulation that PF can achieve higher accuracy than the traditional EKF.     

An Improved Particle Swarm Optimization Algorithm Based on Ensemble Technique

An improved particle swarm optimization （PSO） algorithm based on ensemble technique is presented. The algorithm combines some previous best positions （pbest） of the particles to get an ensemble position （Epbest）, which is used to replace the global best position （gbest）. It is compared with the standard PSO algorithm invented by Kennedy and Eberhart and some improved＇PSO algorithms based on three different benchmark functions. The simulation results show that the improved PSO based on ensemble technique can get better solutions than the standard PSO and some other improved algorithms under all test cases.     

Nano-Cu catalyze hydrogen production from formaldehyde solution at room temperature

In this paper, high efficient production of CO-free hydrogen from formaldehyde (HCHO) aqueous solution catalyzed by various nano-metal catalysts was reported. It was found that nano-metal catalyst could catalyze formaldehyde into hydrogen and formic acid under room temperature and atmospheric pressure. Among Pt, Au, Ni, and Cu nano-metal particles, nano-Cu catalyst exhibited the highest activity and the long-term stability. The temperature seems influence the reaction significantly. For example, when the temperature was increased from 0 to 60 °C, the rate of hydrogen production increases from 2.34 to 140 mL min⁻¹ g⁻¹ catalyst over nano-Cu catalyst. Hydrogen was produced via the formic acid intermediate. When NaOH concentration was high, Cannizzaro reaction occurred, which resulted in the retardation of hydrogen generation at high concentration of NaOH and HCHO.