Solid State Concepts to Understand Catalysis Using Nanoscale Metallic Particles

New advances in theoretical background and recent experimental results concerning nanometer scale metallic clusters are presented. We will begin by a presentation of the advantages and the limitations of synchrotron radiation techniques to characterise nanometer scale entities. Then, through a review of recent papers, we try to make a link between metallic surfaces and nanometer scale monometallic clusters in the case of the interaction with a small molecule, namely NO.     

超微粒子的量子阻尼振动理论

根据SU(1,1)Lie代数,建立超微粒子的量子阻尼振动理论,得到超微粒子量子阻尼振动系统的能级和波函数。     

湖泊藻类叶绿素-α和悬浮物浓度的高光谱定量遥感模型研究

本文利用地物光谱仪对太湖水体进行了光谱测量和同步采样分析，对获得的数据尝试用光谱分离法进行分析，从中分离出蓝藻和悬浮物的特征波峰，建立波峰高度与同步水质采样得到的叶绿素-α浓度和悬浮物浓度的对应关系，得出其遥感定量反演算法，并实际应用在OMIS成像光谱仪图像上．     

用激光粒度分析仪测定二氧化锆粒度

介绍以六偏磷酸钠作为分散剂，采用激光粒度分析仪测量二氧化锆粒度的一种新方法。该方法的测量范围为0．05～300μm。     

Heat transfer mechanism of a swirling impinging jet in a stagnation region

Heat transfer characteristics of a swirling impinging jet have been experimentally examined using a combined particle image velocimetry (PIV) and laser‐induced fluorescence (LIF) technique for simultaneous measurement of velocity and temperature fields. The present study shows that the radial width of the jet stretches with increasing swirl intensity, and that the stretching phenomenon contributes to the maximum local heat transfer coefficient. At the stagnation region, the flow near the heated surface is mixed intermittently by reverse flows toward upstream, and spatial distributions of temperature are correlated with instantaneous velocity vector maps. The dynamic behavior of recirculation zones, attributed to swirl number Sw and impinging distance, mainly determines the turbulent heat transfer at the stagnation region. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(8): 663–673, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10120     

基于TiNi合金的超弹性对其相关磨损机制的FEM研究

本文在重点考虑TiNi合金高弹性变形量的前提下，采用等向强化模型，对不锈钢和超弹TiNi合金在法向接触载荷作用下的六种模型进行了有限元(FEM)分析。结果表明：在相同载荷条件下，超弹TiNi合金产生的von Mises弹性应变要高于不锈钢，但其von Mises应力和塑性应变却恰恰相反，在同一载荷下该合金发生塑性变形的区域要小于不锈钢；此外，超弹TiNi合金发生塑性变形要比不锈钢困难，所需的临界载荷值随其最大弹性变形量(屈服点处的应变值)的增加而增加。最后，基于本文的有限元计算结果对超弹TiNi合金的蘑粒磨损和疲劳磨损机制进行了讨论。     

Sorption of Acid Green 25 on chitosan: Influence of experimental parameters on uptake kinetics and sorption isotherms

Acid Green 25, which is a diazoic dye bearing two sulfonic groups, is efficiently sorbed on chitosan. The protonation of chitosan may explain the electrostatic attraction of this anionic dye and that its optimum pH is close to 3. Preliminary protonation of amine groups (obtained by contact with a sulfuric acid solution) reduced the variation of solution pH following sorbent addition but significantly reduced sorption performance: the maximum sorption capacity of raw chitosan, 525 mg dye/g (0.84 mmol dye/g), was halved by acidic preconditioning. The acidic conditioning also reduced the kinetic rate—the time necessary to reach equilibrium increased up to threefold depending on the experimental conditions. The size of sorbent particles influenced sorption kinetics and equilibrium because of resistance to intraparticle diffusion, but the sorption appeared to occur not only at the surface of the sorbent but also in the intraparticle network of the polymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1073–1080, 2003     

纯镁对碳化硼颗粒的常压浸渗

本文研究了纯镁对不同致密度的碳化硼(B₄C)颗粒基片的常压浸渗性;讨论了镁液对B₄C颗粒聚集体常压浸渗的影响因素;提出了浸渗模型。研究表明,纯镁在氩气保护下,800～850℃温度范围保温30min即可浸渗B₄C颗粒聚集体。浸渗深度和宽度随加热温度升高和保温时间延长而增加;常压浸渗的B₄C_P/Mg复合材料具有很高的硬度,B₄C颗粒在基体中分布较均匀。     

钼精矿结球机理及对策研究

钼精矿产品质量的提高、粒度变细,干燥过程中结球现象严重。在氧化钼的焙烧过程中MoS2残留量较高。本文针对这一现象,分析了其结球机理,提出了相应对策及解决办法。     

Bi3+对纳米MnO2水热合成的影响研究

在中性和酸性条件下，以MnO2作为锰源，通过水热合成了纳米MnO2，通过XRD和TEM对产物进行的观察表明，在酸性条件下，向溶液中添加一定量的Bi^3 ，产物的晶型由α型向γ型转化，产物形貌由针状、丝状向颗粒状转变。