In this paper, there are some physical and mathematics models established about preventing frostdeposit on wet air side of heat exchanger. The effectiveness has been proved both theoretically and practically to preven...In this paper, there are some physical and mathematics models established about preventing frostdeposit on wet air side of heat exchanger. The effectiveness has been proved both theoretically and practically to prevent the frostdeposit in a wet air side of heat exchanger covered with high hydrophobic film. The study results would been shown in two aspects. First, the frost is formed on the surface itself, that is the phenomena in the initial stage of frost formation. Second, dust particles from the air stream can form ice crystals, and the crystals deposit on the surface.展开更多
There is increasing interest in understanding atmospheric phosphorus(P)deposition and its impacts on plant pro-ductivity and carbon sinks in ecosystems.However,the global pattern of P deposition remains poorly underst...There is increasing interest in understanding atmospheric phosphorus(P)deposition and its impacts on plant pro-ductivity and carbon sinks in ecosystems.However,the global pattern of P deposition remains poorly understood,primarily due to the sparseness of data in Asia.In this study,the authors compiled 396 published observations of atmospheric P deposition from 1959 to 2020 on the global scale.The results gave a geometric mean bulk P deposition value of 0.32 kg ha−1 yr−1,or a global P budget of 4.4 Tg yr−1.Compared with the period 1959-2000,the authors found an elevated P deposition in Europe and Asia during 2001-2020,likely due to the increas-ing agricultural emissions and fossil fuel combustion-related sources in addition to dust emissions.The findings highlight the need to quantify the impacts of elevated P deposition from anthropogenic emissions on long-term ecosystem development in the context of carbon neutrality and clean-air actions.展开更多
The catalytic wet air oxidation of aniline over Ru catalysts supported on modified Ti 2 （Ti 2, Ti0.9Ce0.1O2, Ti0.9Zr0.1O2） is investigated. A series of characterization techniques are conducted to deter...The catalytic wet air oxidation of aniline over Ru catalysts supported on modified Ti 2 （Ti 2, Ti0.9Ce0.1O2, Ti0.9Zr0.1O2） is investigated. A series of characterization techniques are conducted to determine the relationship between the physico-chemical properties and the catalytic performance. As a result of the good metal dispersion and large number of surface oxygen species, the Ru/Ti0.9 Zr0.1O2 catalyst presents the best catalytic activity among the tested samples. The effects of the operating conditions on the reaction are investigated and the optimal reaction conditions are determined. Based on the relationship between the by-products concentration and the reaction time, the reaction path for the catalytic oxidation of aniline is established. Carbonaceous deposits on the surface of the support are known to be the main reason for catalyst deactivation. The catalysts maintain a constant activity even after three consecutive cycles.展开更多
The separation method of changeable valence RE element of cerium （Ce） was reviewed in this paper. Solvent extraction is the most effective and efficient method to separate Ce（IV） from RE（III）, usually accompanie...The separation method of changeable valence RE element of cerium （Ce） was reviewed in this paper. Solvent extraction is the most effective and efficient method to separate Ce（IV） from RE（III）, usually accompanied with fluorine （F） and phosphor （P） from bastnaesite and monazite etc. By roast or wet-air oxidation, Ce（III） of bastnaesite and monazite was oxidized into Ce（IV）, and Cyanex923 and [A336][P507] have been investigated to co-extract and recover Ce（IV）, F and P from H2SO4 leaching liquor, leading to favorable conditions for the subsequent separation of Th（IV） and RE（III）. The interaction of Ce（IV） and F and/or P enhances the roasting, leaching and extraction of Ce（IV） due to increasing of the stability of Ce（IV）, and the formation of CeF3 and CePO4 after reductive stripping will benefit the utilization of F and P. For dealing with RE ores of high-content Ce, the clean process of oxidation roasting and Ce（IV）-F separation for Sichuan bastnaesite highlights the advantages of Ce（IV） based clean technique, which firstly demonstrates the comprehensive utilization of Ce（IV）, Th（IV）, F and RE（III） and prevention of environmental pollution from fountainhead. A preliminary flowsheet of two-step oxidation and extraction of Ce（IV） for Bayan Obo mixed ores was further proposed to process the oxidation and extraction of Ce（IV） in presence of both F and P, indicating the possibility of similar effects with clean process of Sichuan bastnaesite. Ce（IV） separation chemistry and clean technique will open up new realms for light RE resources utilization, meeting“Emission Standards of Pollutants from Rare Earths Industry”promulgated by China’s Ministry of Environment Protection （MOP） in 2011.展开更多
通过实验研究,得到不同孔密度的泡沫金属内湿空气的换热和压降特性,并对泡沫金属换热器综合性能进行了分析。测试样件为泡沫铜,孔密度为5~40 PPI（pores per inch）,孔隙率为95%。研究结果表明,由于凝结水的存在,泡沫金属内的湿空气传...通过实验研究,得到不同孔密度的泡沫金属内湿空气的换热和压降特性,并对泡沫金属换热器综合性能进行了分析。测试样件为泡沫铜,孔密度为5~40 PPI（pores per inch）,孔隙率为95%。研究结果表明,由于凝结水的存在,泡沫金属内的湿空气传热系数随着孔密度的增大先增大后减小,孔密度为15 PPI时达到最大值;压降随着孔密度的增大而增大,且大于20 PPI时压降增大更明显。综合考虑传热系数与压降因素,泡沫金属孔密度为15 PPI时综合性能最佳。展开更多
Pt-Ru, Pt and Ru catalysts supported on zirconia were prepared by impregnation method and were tested in selective oxidation of methylamine （MA） in aqueous media. Among three catalysts, Ru/ZrO2 was more active than ...Pt-Ru, Pt and Ru catalysts supported on zirconia were prepared by impregnation method and were tested in selective oxidation of methylamine （MA） in aqueous media. Among three catalysts, Ru/ZrO2 was more active than Pt/ZrO2 while Pt-Ru/ZrO2 demonstrated the best catalytic activity due to the fact that Pt addition efficiently promoted the dispersion of active species in bimetallic catalyst. Therefore, the - 100% TOC conversion and N2 selectivity were achieved over Pt-Ru/ZrO2, Pt/ZrO2 and Ru/ZrO2 catalysts at 190, 220 and 250 ℃, respectively.展开更多
文摘In this paper, there are some physical and mathematics models established about preventing frostdeposit on wet air side of heat exchanger. The effectiveness has been proved both theoretically and practically to prevent the frostdeposit in a wet air side of heat exchanger covered with high hydrophobic film. The study results would been shown in two aspects. First, the frost is formed on the surface itself, that is the phenomena in the initial stage of frost formation. Second, dust particles from the air stream can form ice crystals, and the crystals deposit on the surface.
基金supported by the National Key Research and Development Project[grant numbers 2016YFD0800302 and 2017YFC0210103]。
文摘There is increasing interest in understanding atmospheric phosphorus(P)deposition and its impacts on plant pro-ductivity and carbon sinks in ecosystems.However,the global pattern of P deposition remains poorly understood,primarily due to the sparseness of data in Asia.In this study,the authors compiled 396 published observations of atmospheric P deposition from 1959 to 2020 on the global scale.The results gave a geometric mean bulk P deposition value of 0.32 kg ha−1 yr−1,or a global P budget of 4.4 Tg yr−1.Compared with the period 1959-2000,the authors found an elevated P deposition in Europe and Asia during 2001-2020,likely due to the increas-ing agricultural emissions and fossil fuel combustion-related sources in addition to dust emissions.The findings highlight the need to quantify the impacts of elevated P deposition from anthropogenic emissions on long-term ecosystem development in the context of carbon neutrality and clean-air actions.
基金supported by the National Natural Science Foundation of China(21333003,21577034)National Basic Research Program of China(2013CB933200)+1 种基金National High Technology Research and Development Program of China(2015AA034603)the Fundamental Research Funds for the Central Universities(WJ1514020)~~
文摘The catalytic wet air oxidation of aniline over Ru catalysts supported on modified Ti 2 （Ti 2, Ti0.9Ce0.1O2, Ti0.9Zr0.1O2） is investigated. A series of characterization techniques are conducted to determine the relationship between the physico-chemical properties and the catalytic performance. As a result of the good metal dispersion and large number of surface oxygen species, the Ru/Ti0.9 Zr0.1O2 catalyst presents the best catalytic activity among the tested samples. The effects of the operating conditions on the reaction are investigated and the optimal reaction conditions are determined. Based on the relationship between the by-products concentration and the reaction time, the reaction path for the catalytic oxidation of aniline is established. Carbonaceous deposits on the surface of the support are known to be the main reason for catalyst deactivation. The catalysts maintain a constant activity even after three consecutive cycles.
基金supported by National Natural Science Foundation of China(51174184)the National Basic Research Program of China(2012CBA01202)+1 种基金the Key Research Program of the Chinese Academy of Sciences(KGZD-EW-201-1)the Cooperation Project between CAS and Jiangxi Province
文摘The separation method of changeable valence RE element of cerium （Ce） was reviewed in this paper. Solvent extraction is the most effective and efficient method to separate Ce（IV） from RE（III）, usually accompanied with fluorine （F） and phosphor （P） from bastnaesite and monazite etc. By roast or wet-air oxidation, Ce（III） of bastnaesite and monazite was oxidized into Ce（IV）, and Cyanex923 and [A336][P507] have been investigated to co-extract and recover Ce（IV）, F and P from H2SO4 leaching liquor, leading to favorable conditions for the subsequent separation of Th（IV） and RE（III）. The interaction of Ce（IV） and F and/or P enhances the roasting, leaching and extraction of Ce（IV） due to increasing of the stability of Ce（IV）, and the formation of CeF3 and CePO4 after reductive stripping will benefit the utilization of F and P. For dealing with RE ores of high-content Ce, the clean process of oxidation roasting and Ce（IV）-F separation for Sichuan bastnaesite highlights the advantages of Ce（IV） based clean technique, which firstly demonstrates the comprehensive utilization of Ce（IV）, Th（IV）, F and RE（III） and prevention of environmental pollution from fountainhead. A preliminary flowsheet of two-step oxidation and extraction of Ce（IV） for Bayan Obo mixed ores was further proposed to process the oxidation and extraction of Ce（IV） in presence of both F and P, indicating the possibility of similar effects with clean process of Sichuan bastnaesite. Ce（IV） separation chemistry and clean technique will open up new realms for light RE resources utilization, meeting“Emission Standards of Pollutants from Rare Earths Industry”promulgated by China’s Ministry of Environment Protection （MOP） in 2011.
基金Supported by the National Natural Science Foundation of China(21373245,21173242)the State Key Development Program for Basic Research of China(2013CB632404)+1 种基金the National High Technology Research and Development Program of China(2012AA051501)the Project Support of Gansu Provincial Science &Technology Department(1304FKCA085)
文摘Pt-Ru, Pt and Ru catalysts supported on zirconia were prepared by impregnation method and were tested in selective oxidation of methylamine （MA） in aqueous media. Among three catalysts, Ru/ZrO2 was more active than Pt/ZrO2 while Pt-Ru/ZrO2 demonstrated the best catalytic activity due to the fact that Pt addition efficiently promoted the dispersion of active species in bimetallic catalyst. Therefore, the - 100% TOC conversion and N2 selectivity were achieved over Pt-Ru/ZrO2, Pt/ZrO2 and Ru/ZrO2 catalysts at 190, 220 and 250 ℃, respectively.
