An Electron Spin Resonance Study of Evolution of Organic Free Radicals in Irradiated Pepper During Heat Treatment

ABSTRACT: The thermal evolution behavior of the organic free radicals induced in irradiated black pepper was studied by electron spin resonance spectroscopy. To analyze the time-dependent evolution process, we used the theory of transient phenomena, that is, an ordinal differential equation, as well as the nonlinear least squares numerical method. We found that the radical evolution that occurred in the irradiated pepper obeys a single exponential function and yields a unique time constant. The evolution of the organic free radical undergoes a simple reaction process of a single radical species.     

Filtration of liquid aerosols with a horizontal fibrous filter

The aim of this study was to determine the filtration efficiency and pressure drop in liquid aerosol capture mechanisms using a fibrous coalescent filter. The experimental set-up was designed to measure filtration efficiency and pressure drop through the filter. To avoid the gravimetric effect, the filter was placed horizontally. A series of experiments highlighted the importance of operating conditions such as filtration velocity and aerosol concentration. The results demonstrated the advantage of working at high velocities to minimise the resistance of the medium and to enhance the mass efficiency of the coalescent filter. In parallel, no effect of aerosol concentrations in the pressure drop increase was noted.     

现金流量与公司投资决策--从公司规模角度的实证研究

根据现代公司金融理论，将融资因素引进公司的投资模型，研究不同规模的公司投资与现金流量的关系，并探寻不同规模公司投资决策行为差异的背后动机。实证研究发现：大规模公司投资对现金流量的敏感性要高于小规模公司，动因检验的结果表明大规模公司投资依赖于现金流量源于信息不对称理论，小规模公司源于自由现金流量的代理成本理论，这为我国完善资本市场、制定合理政策提供了借鉴的依据。     

过渡金属元素催化羟自由基反应机理研究

针对显色剂－过渡金属元素－过氧化氢体系，用分光光度法间接测定羟自由基。通过大量试验，确定了三苯甲烷类酸性酚醌吡喃类为有效显色剂，并确定了溴邻苯三酚红－亚铁离子－过氧化氢体系测定羟自由基的最佳条件，首次推测出其最可能的反应机理为：亚铁离子催化过氧化氢产生羟自由基，羟自由基氧化溴邻苯三酚红上的羰基碳氧双键，破坏其显色的共轭结构，使其褪色，此法可作为筛选羟自由基清除剂的有效方法。     

空调系统柔性风管压力损失特性实验与分析

介绍了柔性风管压力损失的理论模型。通过实验研究了两种常用柔性风管在全伸展状态时的压力损失,得出了它们的绝对粗糙度值。给出了柔性风管完全展开时的阻力计算图,可供工程设计时使用。     

Development of a predictive model for polymer/solvent diffusion coefficient calculations

A new calculation procedure for free‐volume parameters is considered in this work by using viscosity prediction methods and the Levenberg‐Marquardt calculation scheme. All parameters used in the Vrentas–Duda free‐volume theory can be estimated from pure component properties. The prediction results are compared with experimental data for some polymer/solvent systems. The diffusion coefficient calculated by Vrentas–Duda theory can be used in the modeling of membrane separation processes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

无氰解吸工艺生产实践

结合生产实践讨论分析了影响载金炭解吸工艺指标的主要因素，介绍了无氰解吸工艺应用效果。     

Thermal Analysis of CNT-Based Nano-Composites by Element Free Galerkin Method

This paper deals with the thermal analysis of carbon nanotube (CNT) based composites by meshless element free Galerkin method. Cylindrical representative volume element (cylindrical RVE) has been chosen to evaluate the thermal properties of nano-composites using multi-domain and simplified approaches. The values of temperature have been calculated at different points and plotted against RVE length and RVE radius. A sensitivity analysis of RVE as well as CNT dimensions has been carried out in detail. The present computations show that the equivalent thermal conductivity is a function of CNT length, CNT radius, RVE length and RVE radius. Based on present numerical simulations, an approximate formula is proposed to calculate the equivalent thermal conductivity of nano-composites. The results obtained by simplified approach have been found in good agreement with those obtained by multi-domain approach.     

土石围堰三维有限元渗流分析及防渗措施研究

为了解决上游围堰防渗及绕坝渗漏问题,确定最优防渗方案,对炳灵水电站右岸松动体防渗帷幕的防渗方案进行了三维有限元渗流计算,并对右岸松动体帷幕的防渗范围和灌浆排数进行了敏感性分析。通过多种防渗方案的计算,对右岸松动体的防渗方案做了相应优化,建议了满足设计要求的防渗方案。     

排气管偏置对PV型旋风分离器性能影响的研究

以Ф300mm、标准PV型旋风分离器为基准模型进行冷态对比实验，研究了排气管与筒体轴线偏心布置对PV型旋风分离器分离性能的影响。结果表明，排气管偏置是进一步提高PV型旋风分离器性能的有效措施之一。在适当的偏心矩和偏置方位下，不仅能降低压降，还可以显著提高分离效率。