WRF模式中的微物理过程及其预报对比试验

WRF(Weather Research Forecast)模式系统是由许多美国研究部门及大学的科学家共同参与进行开发研究的新一代中尺度同化预报系统。本文主要对公开发布的WRF模式V2.0版本中使用的微物理过程方案进行简单介绍,并在国家气象中心建立的与T213中期预报模式相嵌套的预报系统的基础上,对不同微物理过程方案进行了降水预报对比试验和检验,对各方案的降水预报性能进行初步评估。试验结果表明,总体预报效果LIN方案较好,而对流参数化方案从降水落区预报和对流降水对总降水的贡献两方面看则是KF和NKF方案的预报效果较好。

Thermodynamic behaviors of Cu in interaction with chlorine, sulfur, phosphorus and minerals during sewage sludge co-incineration

Thermodynamic equilibrium calculations were performed to reveal effects of interactions among Cl, S, P and other minerals on Cu migration. Our results showed that HCl（g）, SO2（g） and （P2O5）2（g） were released from the sewage sludge co-incineration. Cl was found to weaken adsorption of Cu by Al2O3, CaO and Fe2O3, while S de- layed reactions of Fe2O3 and Al2O3 with Cu, with P having no effect on reactions between the minerals and Cu. Among the coupled systems ofCl, S and P, the co-existences of Cl and S, and Cl, S and P were determined to inhibit Cu volatilization, and the co-existence of Cl and P had an enhancing effect Cu migration was affected only by S in the S and P system. With the SiO2, CaO and Al2O3 system, both Cl alone and Cl and P led to failed reactions be- tween the minerals and Cu. In the systems of S, S and Cl, S and P, and S, Cl and P, the migration behavior of Cu was mainly affected by S at low temperatures and by Cl at high temperatures, whereas P had no effect on Cu mi- gration during the entire nrocess.

Measurement and correlation of physical properties of aqueous solutions of tetrabutylammonium hydroxide, piperazine and their aqueous blends

The density,viscosity and refractive index of aqueous solutions of tetrabutylammonium hydroxide(TBAOH),piperazine(PZ) and their aqueous blends are determined at several temperatures(303.15 to 333.15 K).All these measured physicochemical properties decreases with an increase in temperature.The density data is used to calculate the coefficient of thermal expansion and excess molar volume of all aqueous binary and ternary solutions.The coefficient of thermal expansion increases with increase in temperatures and concentrations.The negativity of excess molar volume for all the aqueous solution decreased with increase in temperature.Each physical property is correlated with temperature by least square method and the corresponding coefficients for each property are presented.The prediction values from correlations for the physical properties are in good agreement with the experimental values.

Chemical and Biological Assessments of the Essential Oils of Chrysophyllum albidum G, Don

The chemical compositions of the essential oils obtained from six tree parts of Chrysophyllum albidum （Sapotaceae） were extracted by hydrodistillation and analyzed by gas chromatography （GC） and gas chromatography-mass spectrometry （GC-MS）. A total of 65, 33, 45, 21, 25 and 18 compounds, representing 79.49%, 100%, 90.81%, 98.43%, 96.62% and 98.37% of the total oil, were identified in the fruit bark, root bark, stem bark, seed bark, leaf and seed, respectively. The dominant compounds in the essential oils in six tree parts were m-xylene （66.7%; seed）, p-xylene （21.4%; seed bark）, a-farnesene （38.1%; leaf）, hexadecanoic acid （14.7%; stem bark）, m-xylene （53.1%; root bark） and hexadecanoic acid （12.7%; fruit bark）. The essential oils were evaluated for their antibacterial, antioxidant and insecticidal activities using Alamar blue assay, DPPH radical scavenging activity and contact toxicity test, respectively. The oils displayed moderate antibacterial potentials to some tested organisms and low radical scavenging activity to DPPH. Rhyzopertha dominica was susceptible to C. albidum stem bark essential oil only.

Basic science of water： Challenges and current status towards a molecular picture

Rapid developments in both fundamental science and modern technology that target water-related problems, including the physical nature of our planet and environment, the origin of life, energy production via water splitting, and water purification, all call for a molecular-level understanding of water. This invokes relentless efforts to further our understanding of the basic science of water. Current challenges to achieve a molecular picture of the peculiar properties and behavior of water are discussed herein, with a particular focus on the structure and dynamics of bulk and surface water, the molecular mechanisms of water wetting and splitting, application-oriented research on water decontamination and desalination, and the development of complementary techniques for probing water at the nanoscale.