The vacuum volatilization kinetics of Pb in In-Pb solder was investigated.The results indicate a significant increase in the vacuum volatilization rates of Pb,25In-75Pb,40In-60Pb,and In with increasing temperatures fr...The vacuum volatilization kinetics of Pb in In-Pb solder was investigated.The results indicate a significant increase in the vacuum volatilization rates of Pb,25In-75Pb,40In-60Pb,and In with increasing temperatures from 923 to 1123 K,system pressure of 3 Pa and holding time of 30 min.The mass transfer coefficients and apparent activation energies of Pb and its alloys were determined at various temperatures.Additionally,a kinetics model was developed to describe Pb vacuum volatilization in high-temperature melts.It is obtained that the vapor mass transfer is the factor limiting the vacuum volatilization rates of Pb and In-Pb alloys under the above specified conditions.展开更多
The substitution of traditional blast furnaces with steel-belt furnaces for antimony smelting was proposed.The influence of various parameters on the oxidative volatilization of stibnite was studied according to the p...The substitution of traditional blast furnaces with steel-belt furnaces for antimony smelting was proposed.The influence of various parameters on the oxidative volatilization of stibnite was studied according to the production practice of steel-belt furnaces.Furthermore,the kinetics of oxidative volatilization was elucidated using differential thermal gravimetric analyses and non-isothermal analysis methods.The results indicated that the oxygen concentration and the temperature were pivotal variables in the oxidative volatilization process.Notably,the volatilization efficiency of antimony was 97.25%under optimal conditions.Moreover,the kinetic control stages were divided into chemical reaction control(440-490°C),internal diffusion control(500-550°C),and chemical reaction control(560-580°C).These stages corresponded to activation energies of 16.40-18.79,120.86-195.96,and 24.00-28.31 kJ/mol,respectively.展开更多
Bio-availability of different forms of selenium and its rate of volatilization from soils in Chinese low-selenium belt were examined. Adding directly solutions of either inorganic or organic selenium compounds to soil...Bio-availability of different forms of selenium and its rate of volatilization from soils in Chinese low-selenium belt were examined. Adding directly solutions of either inorganic or organic selenium compounds to soil could only slightly increase the rate of selenium volatilization from soil. Volatilization of selenium from soil was largely enhanced when certain nutritional solutions along with selenium compounds were added. Garlic water extract and seleno-amino acids, i.e., seleno-methionine and seleno-cysteine, were found more effective for their bio-availability to the volatilization process. Under laboratory simulating conditions, the volatilization rate of selenium from different types of soils in Chinese low-selenium belt was found in the range of 0.10-0.27 ng.kg-1 soil.day-1 over a 17 days period, generally followed by a decline with time of incubation.展开更多
Temperature has a substantial impact on the emission of biogenic volatile organic compounds(BVOCs).Moder-ate warm temperatures,e.g.,30–40°C,could boost plant metabolism,increasing BVOC emissions.Against the back...Temperature has a substantial impact on the emission of biogenic volatile organic compounds(BVOCs).Moder-ate warm temperatures,e.g.,30–40°C,could boost plant metabolism,increasing BVOC emissions.Against the backdrop of global warming,plants emit more BVOCs to cope with thermal stress,leading to elevated concen-trations of tropospheric ozone(O_(3))and secondary organic aerosols(SOA).In recent years,a considerable body of research has explored the interaction between tree species and BVOCs under the influence of various environ-mental factors.Although many studies have examined explored the temperature dependence of BVOC emissions in the past,few studies have conducted a comprehensive and in-depth investigation into the impacts of tempera-ture.This review summarizes the relevant studies on BVOCs in the past decade,including the main biosynthetic pathways,emission observation techniques and emission inventories,as well as how temperature affects isoprene and monoterpene emission rates and the formation of O_(3) and SOA.Our work offers a theoretical foundation and guidance for future efforts to advance the comprehension of BVOC emission characteristics and develop strategies to mitigate secondary pollution.展开更多
The Ru-based catalysts with different preparation methods or supports were achieved and applied in efficientlycatalytic elimination of 1,2-dichloroethane(1,2-DCE).It wasfirstly found that the redox ability and chlorine...The Ru-based catalysts with different preparation methods or supports were achieved and applied in efficientlycatalytic elimination of 1,2-dichloroethane(1,2-DCE).It wasfirstly found that the redox ability and chlorine re-sistance of the catalyst could be improved by regulating the interaction between Ru and supports.Compared withother supports and conventionally impregnated methods,the Ru@ZSM-5 catalyst synthesized by the in-situ en-capsulation strategy exhibited an excellent low-temperature catalytic performance(T50=262°C,T90=327℃),superior stability in long-term test as well as ideal target products.The acidity,specific surface area,and in-teraction with precious metals of the supports have significant influences on the catalytic activity,and the Ruclusters inside the pore structures are more closely bound to the framework Al species,which promotes theoxidation behavior.The encapsulation strategy also significantly improves the Ru dispersion thereby facilitatesoxygen activation as well as Cl-containing volatile organic compounds(CVOCs)deep oxidation,and preserveslarge amounts of Brønsted acid sites to optimize the hydrolysis mechanism for purification of CVOCs.Subse-quently,the synergistic effect between metal redox and acidity is greatly optimized,thus extremely promotingthe catalytic efficiency of 1,2-DCE oxidation.展开更多
为实现南极磷虾(Euphausia superba)品质的快速评定,本研究将近红外光谱技术(Near infrared spectroscopy,NIRS)与偏最小二乘法(Partial least squares,PLS)相结合,构建用于快速预测磷虾体内非蛋白氮(Non-protein nitrogen,NPN)含量和...为实现南极磷虾(Euphausia superba)品质的快速评定,本研究将近红外光谱技术(Near infrared spectroscopy,NIRS)与偏最小二乘法(Partial least squares,PLS)相结合,构建用于快速预测磷虾体内非蛋白氮(Non-protein nitrogen,NPN)含量和挥发性盐基氮(Total volatile base nitrogen,TVB-N)含量的近红外定量分析模型。采集近红外光谱后,通过比较决定系数(Coefficient of determination,R^(2))、校正标准偏差(Root mean square error of calibration,RMSEC)、预测标准偏差(Root mean square error of prediction,RMSEP)等模型的评价参数,选取近红外光谱定量分析模型的最佳预处理方式、特征光谱范围以及主因子数。结果显示,NPN含量模型的最佳预处理方法为多元散射校正(Multiplicative signal correction,MSC),其特征光谱范围为8887.1~7774.2 cm-1;TVB-N含量模型则采用MSC与卷积平滑(Savitzky-Golay smoothing,SG)相结合的方式进行预处理,建模范围为全波段。两个定量模型的主因子数均为5。经模型的优化与外部验证,最终构建的PLS最优模型如下:NPN含量近红外定量分析模型的R^(2)为0.9384,RMSEC为0.279,RMSEP为0.443;TVB-N含量近红外定量分析模型的R^(2)为0.8685,RMSEC为3.800,RMSEP为4.070。研究结果表明,两个模型均具有良好的预测精度(R^(2)>0.85)和稳定性,其中NPN定量分析模型的预测能力优于TVB-N定量分析模型。综上,本研究基于NIRS与PLS构建的定量分析模型能够有效预测南极磷虾体内的NPN和TVB-N含量,为南极磷虾的品质评价提供了可靠的技术支持,满足快速评定的实际应用需求。展开更多
米酒曲中微生物种类多样,微生物之间的相互作用影响着米酒的风味与品质。该研究基于高通量测序技术分析了我国南方地区米酒曲中微生物菌群多样性,研究结果表明,雷尔氏菌属(Ralstonia)和魏斯氏菌属(Weissella)为东南组和中部组的共同优...米酒曲中微生物种类多样,微生物之间的相互作用影响着米酒的风味与品质。该研究基于高通量测序技术分析了我国南方地区米酒曲中微生物菌群多样性,研究结果表明,雷尔氏菌属(Ralstonia)和魏斯氏菌属(Weissella)为东南组和中部组的共同优势细菌属,东南组的优势细菌属为红球菌属(Rhodococcus)(14.6%),东南组中5个组的菌群结构在属水平上类似,表明米酒曲的菌群结构与地域环境有一定联系。根霉属(Rhizopus)在所有米酒曲样品中占绝对优势(80.98%~99.22%)。米酒曲中细菌菌落总数最高的为湖北省孝感地区的酒曲(8.21 lg CFU/g),霉菌孢子数最高的为广东佛山的酒曲(9.61 lg个/g),酵母菌菌落总数最高的为安徽省阜阳市地区的酒曲(10.02 lg CFU/g)。同时,筛选获得酒曲中优势菌株功能菌4株,将4株功能菌株接种强化米酒曲,结果表明同时接种商业酒曲和功能菌株(SG组)的酒曲糖化酶、蛋白酶活力分别提高至1583.4 U和776.13 U/g,SG组的酯类物质种类最多达到17种,并且SG组的醇类、酯类和烷烃类物质的含量均显著提高,分别达到了1021.94、1190.82、535.80μg/100 g,表明功能菌在米酒及米酒曲中应用潜力巨大。展开更多
基金financially supported by the Fundamental Research Project of Yunnan Province,China(Nos.202301AW070020,202201AT070229,202105AC160091,202202AB080018).
文摘The vacuum volatilization kinetics of Pb in In-Pb solder was investigated.The results indicate a significant increase in the vacuum volatilization rates of Pb,25In-75Pb,40In-60Pb,and In with increasing temperatures from 923 to 1123 K,system pressure of 3 Pa and holding time of 30 min.The mass transfer coefficients and apparent activation energies of Pb and its alloys were determined at various temperatures.Additionally,a kinetics model was developed to describe Pb vacuum volatilization in high-temperature melts.It is obtained that the vapor mass transfer is the factor limiting the vacuum volatilization rates of Pb and In-Pb alloys under the above specified conditions.
基金supported financially by the National Natural Science Foundation of China(No.52074362)。
文摘The substitution of traditional blast furnaces with steel-belt furnaces for antimony smelting was proposed.The influence of various parameters on the oxidative volatilization of stibnite was studied according to the production practice of steel-belt furnaces.Furthermore,the kinetics of oxidative volatilization was elucidated using differential thermal gravimetric analyses and non-isothermal analysis methods.The results indicated that the oxygen concentration and the temperature were pivotal variables in the oxidative volatilization process.Notably,the volatilization efficiency of antimony was 97.25%under optimal conditions.Moreover,the kinetic control stages were divided into chemical reaction control(440-490°C),internal diffusion control(500-550°C),and chemical reaction control(560-580°C).These stages corresponded to activation energies of 16.40-18.79,120.86-195.96,and 24.00-28.31 kJ/mol,respectively.
文摘Bio-availability of different forms of selenium and its rate of volatilization from soils in Chinese low-selenium belt were examined. Adding directly solutions of either inorganic or organic selenium compounds to soil could only slightly increase the rate of selenium volatilization from soil. Volatilization of selenium from soil was largely enhanced when certain nutritional solutions along with selenium compounds were added. Garlic water extract and seleno-amino acids, i.e., seleno-methionine and seleno-cysteine, were found more effective for their bio-availability to the volatilization process. Under laboratory simulating conditions, the volatilization rate of selenium from different types of soils in Chinese low-selenium belt was found in the range of 0.10-0.27 ng.kg-1 soil.day-1 over a 17 days period, generally followed by a decline with time of incubation.
基金supported by the National Key R&D Program of China(No.2024YFC3714200)Guangxi Key Research and Development Program,China(No.Guike AB24010074)+2 种基金the National Natural Science Foundation of China(Nos.22276099,U24A20515 and 22361162668)the Natural Science Foundation of Jiangsu Province(No.BK20240036)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX24_1529).
文摘Temperature has a substantial impact on the emission of biogenic volatile organic compounds(BVOCs).Moder-ate warm temperatures,e.g.,30–40°C,could boost plant metabolism,increasing BVOC emissions.Against the backdrop of global warming,plants emit more BVOCs to cope with thermal stress,leading to elevated concen-trations of tropospheric ozone(O_(3))and secondary organic aerosols(SOA).In recent years,a considerable body of research has explored the interaction between tree species and BVOCs under the influence of various environ-mental factors.Although many studies have examined explored the temperature dependence of BVOC emissions in the past,few studies have conducted a comprehensive and in-depth investigation into the impacts of tempera-ture.This review summarizes the relevant studies on BVOCs in the past decade,including the main biosynthetic pathways,emission observation techniques and emission inventories,as well as how temperature affects isoprene and monoterpene emission rates and the formation of O_(3) and SOA.Our work offers a theoretical foundation and guidance for future efforts to advance the comprehension of BVOC emission characteristics and develop strategies to mitigate secondary pollution.
基金supported by the National Key Research and Development Program of China(No.2023YFC3905400)the National Natural Science Foundation of China(No.22176010).
文摘The Ru-based catalysts with different preparation methods or supports were achieved and applied in efficientlycatalytic elimination of 1,2-dichloroethane(1,2-DCE).It wasfirstly found that the redox ability and chlorine re-sistance of the catalyst could be improved by regulating the interaction between Ru and supports.Compared withother supports and conventionally impregnated methods,the Ru@ZSM-5 catalyst synthesized by the in-situ en-capsulation strategy exhibited an excellent low-temperature catalytic performance(T50=262°C,T90=327℃),superior stability in long-term test as well as ideal target products.The acidity,specific surface area,and in-teraction with precious metals of the supports have significant influences on the catalytic activity,and the Ruclusters inside the pore structures are more closely bound to the framework Al species,which promotes theoxidation behavior.The encapsulation strategy also significantly improves the Ru dispersion thereby facilitatesoxygen activation as well as Cl-containing volatile organic compounds(CVOCs)deep oxidation,and preserveslarge amounts of Brønsted acid sites to optimize the hydrolysis mechanism for purification of CVOCs.Subse-quently,the synergistic effect between metal redox and acidity is greatly optimized,thus extremely promotingthe catalytic efficiency of 1,2-DCE oxidation.
文摘为实现南极磷虾(Euphausia superba)品质的快速评定,本研究将近红外光谱技术(Near infrared spectroscopy,NIRS)与偏最小二乘法(Partial least squares,PLS)相结合,构建用于快速预测磷虾体内非蛋白氮(Non-protein nitrogen,NPN)含量和挥发性盐基氮(Total volatile base nitrogen,TVB-N)含量的近红外定量分析模型。采集近红外光谱后,通过比较决定系数(Coefficient of determination,R^(2))、校正标准偏差(Root mean square error of calibration,RMSEC)、预测标准偏差(Root mean square error of prediction,RMSEP)等模型的评价参数,选取近红外光谱定量分析模型的最佳预处理方式、特征光谱范围以及主因子数。结果显示,NPN含量模型的最佳预处理方法为多元散射校正(Multiplicative signal correction,MSC),其特征光谱范围为8887.1~7774.2 cm-1;TVB-N含量模型则采用MSC与卷积平滑(Savitzky-Golay smoothing,SG)相结合的方式进行预处理,建模范围为全波段。两个定量模型的主因子数均为5。经模型的优化与外部验证,最终构建的PLS最优模型如下:NPN含量近红外定量分析模型的R^(2)为0.9384,RMSEC为0.279,RMSEP为0.443;TVB-N含量近红外定量分析模型的R^(2)为0.8685,RMSEC为3.800,RMSEP为4.070。研究结果表明,两个模型均具有良好的预测精度(R^(2)>0.85)和稳定性,其中NPN定量分析模型的预测能力优于TVB-N定量分析模型。综上,本研究基于NIRS与PLS构建的定量分析模型能够有效预测南极磷虾体内的NPN和TVB-N含量,为南极磷虾的品质评价提供了可靠的技术支持,满足快速评定的实际应用需求。
文摘米酒曲中微生物种类多样,微生物之间的相互作用影响着米酒的风味与品质。该研究基于高通量测序技术分析了我国南方地区米酒曲中微生物菌群多样性,研究结果表明,雷尔氏菌属(Ralstonia)和魏斯氏菌属(Weissella)为东南组和中部组的共同优势细菌属,东南组的优势细菌属为红球菌属(Rhodococcus)(14.6%),东南组中5个组的菌群结构在属水平上类似,表明米酒曲的菌群结构与地域环境有一定联系。根霉属(Rhizopus)在所有米酒曲样品中占绝对优势(80.98%~99.22%)。米酒曲中细菌菌落总数最高的为湖北省孝感地区的酒曲(8.21 lg CFU/g),霉菌孢子数最高的为广东佛山的酒曲(9.61 lg个/g),酵母菌菌落总数最高的为安徽省阜阳市地区的酒曲(10.02 lg CFU/g)。同时,筛选获得酒曲中优势菌株功能菌4株,将4株功能菌株接种强化米酒曲,结果表明同时接种商业酒曲和功能菌株(SG组)的酒曲糖化酶、蛋白酶活力分别提高至1583.4 U和776.13 U/g,SG组的酯类物质种类最多达到17种,并且SG组的醇类、酯类和烷烃类物质的含量均显著提高,分别达到了1021.94、1190.82、535.80μg/100 g,表明功能菌在米酒及米酒曲中应用潜力巨大。
