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Effect of acid oxidization of carbon nanotube electrode on the capacitances of double layer capacitors

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Science china(Technological Sciences) 2004年第3期47卷 257-264页

作者： Li Chensha1,WANG Dazhi1,LIANG Tongxiang2.WANG Xiaofeng1 & LIANG Ji1 1. Department of Mechanical Engineering, tsinghua university,Beijing 100084, china {2., tsinghua university,beijng 1.2201.china tsinghua Univ Dept Mech Engn Beijing 100084 Peoples R China tsinghua Univ Inst Nucl Energy Technol Beijing 102201 Peoples R China

Polarizable electrode of electric double layer capacitor was made from carbon nanotubes. The effect of acid oxidation of electrode on the specific capacitance was studied. Oxidation removed the redundant carbon, expanded the pore size and introducedf some kinds of functional groups on the surface of CNTs. The specific capacitance of the electrodes winth organic electrolyte was increased from 2..4 to 49.6 F/g after being oxidized at a volume ratio H2.O4 to HNO3 of 3:1.

关键词： carbon nanotubes, electric double layer capacitor, specific capacitance.

Kinetics study on the dissolution of UO_2.particles by microwave and conventional heating in 4 mol/L nitric acid

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Science china Chemistry 2008年第7期51卷 700-704页

作者： ZHAO YunFeng & CHEN Jing institute of nuclear and New {2. technology, tsinghua university, Beijing 1.2201, china institute of nuclear and New {2. technology Tsinghua UniversityBeijing 102201China

The dissolution of UO2.particles in 4 mol·L-1 nitric acid medium at temperatures of 90-110℃ by mi- crowave heating and conventional heating has been investigated, respectively. It is found that the dissolution ratios of UO2.particles by microwave heating were 10%-40% higher than that by conven- tional heating. Kinetics research shows that the dissolution of UO2.particles in 4 mol·L-1 nitric acid is controlled by the diffusion control model for microwave heating and by the surface reaction control model for conventional heating. The diffusion control model for the dissolution of UO2.particles by mi- crowave heating could be explained by the diffuseness on the surface of UO2.particles.

关键词： uranium dioxide nitric acid dissolution microwave heating

Simulating　Experimental　Investigation　on　the　Safety　of　nuclear　Heating　Reactor　in　Loss－of－Coolant　Accidents

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Journal of Thermal Science 1996年第4期5卷 285-291页

作者： Zhanjie Xu(institute of nuclear {2. technology, tsinghua university, Beijing, 100084, china) institute of nuclear {2. technology Tsinghua University Beijing China

The 5MW low temperature nuclear heating reactor (NHR-5) is a new and advanced type of nuclear reactor developed by {2. of nuclear energy technology (INET) of tsinghua university of china in 1989. Its main loop is a thermal-hydraulic system with natural circulation. This paper studies the safety of NHR under the condition of loss-of-coolant accidents (LOCAs) by means of simulant experiments. First, the background and necessity of the experiments are presented, then the experimental system, including the thermal-hydraulic system and the data collection system, and similarity criteria are introduced. UP to now, the discharge experiments with the residual heating power (2.% rated heating power) have been carried out on the experimental system. The system parameters including circulation flow rate, system pressure, system temperature, void fraction, discharge mass and so on have been recorded and analyzed. Based on the results of the experiments, the conclusions are shown as folios: on the whole, the reactor is safe under the condition of LOCAs, but the thermal vacillations resulting from the vibration of the circulation flow rate are disadvantageous to the internal parts of the reactor core.

关键词： nuclear heating reactor natural circulation LOCA safety.

Degradation of 4-chlorophenol in aqueous solution by γ-radiation and ozone oxidation

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Science china Chemistry 2006年第2期49卷 186-192页

作者： HU Jun1, WANG Jianlong1,2.& CHEN Rong1 1. Laboratory of Environmental technology, institute of {2. energy technology, tsinghua university, Beijing 100084, china 2. State Key Joint Laboratory of Environmental Simulation and Pollution Control, tsinghua university, Beijing 100084, china Correspondence should be addressed to Wang Jianlong 1. Laboratory of Environmental technology Institute of Nuclear Energy Technology Tsinghua University Beijing 100084 China 2. State Key Joint Laboratory of Environmental Simulation and Pollution Control Tsinghua University Beijing 100084 China

The degradation of 4-chlorophenol (4-CP) by using gamma rays generated by a 60Co source in the presence of O3 was investigated. The radiolysis of 4-CP and the kinetics of 4-CP min-eralization were analyzed based on the determination of total organic carbon (TOC). The influence of initial 4-CP concentration and the free radicals scavengers (such as NaHCO3 and t-butanol) on the 4-CP degradation was also studied. The results showed that when the radiation rate was 336 Gy·min?1, 4-chlorophenol at concentration of 10 mg·L?1 could be completely degraded at the radiation dose of 2.kGy. The degradation of 4-chlorophenol could be described by a first-order reaction model, the rate constant of 4-CP degradation by combined ozonation and radiation was 0.1016 min?1, which was 2.4 times higher than the sum of radiation (0.02.4 min?1) and ozonation (0.0137 min?1). It re-vealed that the combination of radiation and ozonation resulted in synergistic effect, which can re-markably increase the degradation efficiency of 4-CP.

关键词： radiolysis, 4-chlorophenol, priority pollutant, degradation, O3, synergistic effect, kinetics.

Carbon emission permit allocation and trading

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Journal of Environmental Sciences 1999年第4期11卷 468-473页

作者： CHEN Wen\|ying, WU Zong\|xin (institute of nuclear {2. technology, tsinghua university, Beijing 100084, china) 清华大学核能技术设计研究院北京

Nowadays our earth is faced with grim challenge of global climate change. All countries should go into action jointly to mitigate climate change. Carbon emission permit allocation and trading are two important issues to realize global cooperation. In this paper two kinds of comprehensive carbon emission permit allocation methods not only considering equity but also efficiency were advanced. After the carbon permit price was determined, the trading situations in various regions or countries in the world and the global benefits gained from emission trading were expounded. Moreover, the impact of carbon emission permit trading on chinas economy was analyzed.

关键词： climate change carbon permit allocation carbon permit trading comprehensive allocation method

Free　radical　oxidation　of　spent　radioactive　organic　solvent

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Journal of Environmental Sciences 1997年第2期9卷 77-82页

作者： Ji Xiaoyuan, Zhao Bin institute of nuclear {2. technology, tsinghua university, Beijing 100084, china

The decomposition of radioactive Spent Organic Solvent (SOS) was conducted successfully in bench scale tests. The experiment results showed that TBP/OK can be decomposed under with in H 2. 2. Fe 2. /TiO 2. H 2.O 4 systems under suitable H 2. 2.concentration, catalyst, temperature and pH. The free radical oxidation reaction mechanism using H 2. 2.under the action of the synergistic catalysis TiO 2.Fe 2. was also discussed briefly.

关键词： spent organic solvent catalytic oxidation synergetic catalysis.

RECOVERY OF CADMIUM AND NICKEL FROM SCRAP Ni-Cd BATTERIES

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Acta Metallurgica Sinica(English Letters) 2001年第4期14卷 303-312页

作者： J.X. Zhu1), B. Yu2., J.H. Li1) and Y.F. Nie1) 1) Department of Environmental Engineering, tsinghua university, Beijing 100084, china {2., tsinghua university, Beijing 100084, china Dept. of Environ. Eng. Tsinghua Univ. Beijing 100084 China

Several typical methods for the recovery of Ni-Cd batteries are described in detail. Based on the comparison between the hydrometallurgical process and the pyrometallurgical process, the latter is selected as the suit... 详细信息

关键词： Cadmium Nickel Recovery Scrap metal

Two-dimensional numerical simulation of hydrodynamic behaviors of drop covered with vapor film

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Science china(Technological Sciences) 2005年第2期48卷 180-190页

作者： DUAN Riqiang, JIANG Shengyao, ZHANG Youjie, JIA Haijun & YANG Xingtuan institute of nuclear and New {2. technology, tsinghua university Advanced Reactor Engineering and Safety, Key Laboratory of MOE of china, Beijing 1.2201, china 1. institute of nuclear and New {2. technology Tsinghua University 102201 Beijing China 2. Advanced Reactor Engineering and Safety Key Laboratory of MOE of China 102201 Beijing China

The breakup of drop covered with vapor film is numerically simulated. The moving particle semi-implicit method is used to solve the 2.dimensional unsteady Navier-Stokes equations for drop, vapor and ambient fluid. The results show that vapor film suppresses the drop breakup and hence the critical Weber number increases with the increasing thickness of vapor film. The breakup process can be divided into two stages. The drop deformation and breakup mainly occur in the later stage. Three breakup mechanisms are unveiled, which are almost the same as that of drop breakup without vapor film except for the stronger Rayleigh-Taylor instability for drop with vapor film. Our simulation results are comparable with the previous experiments.

关键词： drop breakup, vapor film, numerical simulation, particle method, moving particle semi-implicit method.

Fundamental study of CO_2.control technologies and policies in china

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Science china(Technological Sciences) 2008年第7期51卷 857-870页

作者： JIN HongGuang1, ZHANG XiLiang2. GAO Lin1, YUE Li2. HE JianKun2.& CAI RuiXian1 1 institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100080, china 2.institute of nuclear and New energy technology, tsinghua university, Beijing 100084, china 1. institute of Engineering Thermophysics Chinese Academy of Sciences Beijing 100080 China 2. institute of nuclear and New {2. technology Tsinghua University Beijing 100084 China

The technical roadmap and policies for CO2.mitigation suitable for china are a common center of attention in the fields of energy, environment, and management science in the country. Emphasizing interaction between technical research and policy research, this work discovers the potential breakthrough in the integrated field. The technical difficulties of recovering CO2.are pointed out, the mechanism of combining CO2.recovery with energy conversion is investigated, and the basic principle for integrating an environmental-friendly energy system is discussed. Moreover, the formulation of a new energy system that can recover CO2.with very low or even zero energy penalty is proposed, while the assessment methodology and model system for the technical roadmap of CO2.emission control are developed. Finally, a new technical roadmap constructing an energy network suitable for china is proposed, which may provide a new way for the development of sustainable energy and environment technologies.

关键词： CO2 capture and storage technical roadmap energy policy