Treatment of Red Tide in Ocean Using Non-Thermal Plasma Based Advanced Oxidation Technology*

A Pilot-scale experiment for the treatment of red tide in the enclosure was done in sea area of Shandong Province, P.R. China on Aug. 25, 2002. With the method of micro-gap discharge, O₂ in air and H₂O in seawater are ionized and dissociated into large numbers of OH^• radicals, and then dissolved into a part of seawater to form OH^• solution of high concentration. With OH^• concentration of 0.68 mg/L, the kill efficiencies of 29 kinds of red tide organisms such as Chaetoceros lorenzianus and so on reached 99.89%, in which bacterium and vibrio were reduced below the detection limit, also Gonyaulax cysts and Prei. Cysts with the crust were done the lowest limit of test. At the same time, the content of chlorophyll-a was decreased below the detection limit. DO (dissolved oxygen) saturation of seawater was greatly increased to 100% because the residual OH^• radical was decomposed into H₂O and O₂ after 20 min. Therefore the treatment of red tide using OH^• radicals is a kind of advanced oxidation technology, which realizes zero pollution, zero emission and zero residual in the process of the production of OH^• radicals and the treatment of red tide.*Key project of National Foundation Research from Science and Technology Ministry of China, (2002CCC00900); key project of National Natural Science Foundation of China (NSFC; 60031001).     

A new and Facile Method for Synthesis of AZA-Wittig Reagents under Microwave Irradiation

We report a simple and quick synthetic method of some new Aza-Wittig reagents in anhydrous acetonitrile under microwave irradiation. 1-Substituted aryl-4-ethoxycarbonyl-5-[(triphenylphosphoranylidene)amino]-1, 2, 3-triazoles can be obtained within three minutes by microwave irradiation to the mixture of 1-substituted aryl-4-ethoxycarbonyl-5-amino-1,2,3-triazoles, triphenylphosphine, hexachloroethane and triethylamine. The products were characteried by IR, NMR, MS methods and elemental analysis.     

Synthesis of Ammonia Using CH4/N2 Plasmas Based on Micro-Gap Discharge under Environmentally Friendly Condition

The synthesis of ammonia has been studied in methane-nitrogen plasmas using a micro-gap discharge under an environmentally friendly condition. The effects of some parameters such as the specific input energy, the discharge gap, the volume ratio of CH₄/N₂, the residence time, and the gas temperature on the yield of NH₃ and conversion rate of CH₄ are discussed in the paper. The results show that the highest yield of NH₃ is 8000 ppm for a residence time of 1.6 s. In addition, the yield and generating rate of H₂ are 9.1% (v/v) and 1879.8 μmol/min, respectively. Therefore, the micro-gap discharge is an efficient method for NH₃ synthesis and H₂ generation from CH_4.     

·OH Treatment for Killing of Harmful Organisms in Ship’s Ballast Water with Medium Salinity Based on Strong Ionization Discharge

A novel discharge mode consisting of alternate discharge of a micro-streamer and micro-glow was developed to induce the formation of ·OH radicals in ballast water. A series of ·OH killing experiments were then conducted using medium salinity ballast water. Five species of algae from three different phyla and three kinds of bacteria were killed by ·OH radicals in compliance with the D-2 ballast water standard of International Maritime Organization. Moreover, the chlorophyll-a was fully discolored when the total reactive oxidants was 2.5 mg/L, indicating that the algae had died. Overall, the quality of medium salinity ballast water with heavy pollution was greatly improved. These results indicate that the use of ·OH radicals is an effective method for the treatment of ship’s ballast water.     

Self-assembly of highly uniform LiFePO4 hierarchical nanostructures by surfactant molecules in a new mixture medium

In this work, the LiFePO₄ samples are synthesized in ethylene glycol/water (EG/W) and aqueous solution, respectively. The samples are characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, electron diffraction, and nitrogen adsorption isotherms. The results show that the reaction medium and the surfactant molecules have the significant influences on the particle morphology. In the presence of dodecylbenzenesulfonic acid sodium, the highly uniform LiFePO₄ hierarchical nanostructures are obtained in EG/W, which consist of the nanoplates. Nevertheless, the irregular LiFePO₄ microparticles are obtained in aqueous solution. Furthermore, the electrochemical properties of the samples are mainly investigated. The hierarchical LiFePO₄ sample exhibits a higher rate capability and an improved cyclability than the aggregated irregular microparticles, which have been ascribed to the highly uniform hierarchical nanostructures.     

An Ozone Generator of Miniaturization and Modularization with the Narrow Discharge Gap

The method of ionization discharge has a key action on the process of the ionization and decomposition of O₂ molecule as well as the re-decomposition of O₃ molecule. In this paper, an ozone generation of miniaturization which was fabricated by stacking discharge modules with rectangle is introduced, only volume of 23.0×53.0×42.0 cm³ for ozone production capacity of 1 kg/hr. In addition, the ozone concentration and its production efficiency are significantly improved in comparison with a conventional ozone generator, which have the highest ozone concentration of 308 g/Nm³ and the production efficiency of 118 g/kWh at ozone concentration of 200 g/Nm³.     

Enhanced cyclability of CdS/TiO2 photocatalyst by stable interface structure

CdS nanoparticles were in situ deposited on TiO₂ nanosheets and nanorods under hydrothermal conditions, respectively. The effect of CdS–TiO₂ interface structure on hydrogen production activity was mainly investigated under visible light irradiation. The results showed that the TiO₂ nanosheet-based CdS/TiO₂ showed a higher activity and a higher cyclability than the nanorod-based sample due to the stronger interaction of CdS with the (0 0 1) facets of TiO₂ than with the (1 0 1) facets. It was proposed that the strong interaction between CdS nanoparticles and TiO₂ nanosheets effectively refrains the recombination of electrons and holes.     

组合式热管换热器在热泵系统中的试验研究

采用组合式热管换热器作为生活浊水余热热泵热水器的热管蒸发器,并在试验台上进行了不同污水进口温度和不同污水流量的可视化试验,通过分析试验结果,发现组合式热管上升管和下降管的温差很大的现象,这与热管特性相矛盾。采用理论分析和实验相结合的方法,研究了热管中产生温差的原因。它主要是由于下降管压力损失较大,使热管工质在热管蒸发器中的滞留引起。     

物理实验课程体系教学改革的初探

本文阐述了物理实验课程教学改革的构思和试点进展情况；改变了传统的实验课教学模式     

Chiral (S)‐(+) 1‐Substituted Aryl‐4‐(1‐phenyl) Ethylformamido‐5‐amino‐1,2,3‐triazole: A New Class of Chiral Ligands for the Silver(I)‐Promoted Enantioselective Allylation of Aldehydes

Some novel chiral ligands, (S)‐(+) 1‐substituted aryl‐4‐(1‐phenyl) ethylformamido‐5‐amino‐1,2,3‐triazoles, were prepared starting from 1‐substituted aryl‐4‐ethoxycarbonyl‐5‐amino‐1,2,3‐triazoles and other reagents. They were used as catalytic chiral ligands in the silver (I)‐promoted enantioselective allylation reaction of aldehydes with allyltributyltin.