Objective] This study was conducted to evaluate the product quality and safety of Peristrophe roxburghiana_ col ected from different places in Hechi City, northwest of Gunagxi, so as to provide basic data for further ...Objective] This study was conducted to evaluate the product quality and safety of Peristrophe roxburghiana_ col ected from different places in Hechi City, northwest of Gunagxi, so as to provide basic data for further development and uti-lization of the characteristic plant resource P. roxburghiana. [Method] Contents of 9 kinds of heavy metals including Cd, Mn, Pb, Zn and Cu in the herb were deter-mined by the method of wet digestion-flame atomic absorption spectrophotometry and atomic fluorescence spectrometry, respectively. [Results] Heavy metal contents of Cd, Mn, Pb, Fe, Cu, Zn, As, Hg and Se were 1.62-17.25, 8.93-142.53, 4.37-18.43, 103.7-242.81, 2.55-5.35, 85.40-146.30, 0.07-0.54, 0.00-0.08 and 0.00-0.47 mg/kg, respectively. According to the national food safety standards and Green Trade Standards of lmporting ＆amp; Exporting Medicinal plants ＆amp; Preparations, the heavy metal contents of the P. roxburghiana_samples col ected from different coun-ties in Hechi City exceeded standards or at the critical values. Among which, Cd, Pb and Zn contents of the samples are seriously higher than the standards. [Con-clusion] Therefore, the impact of soil heavy metal pol ution on the safety of edible plants in the northwest of Guangxi should be highly concerned.展开更多
In this work,several ceria-zirconia based catalysts with very lo w(and equimolar) metal contents were prepared,characterised and tested for the CO oxidatio n reaction(under lean and stoichiometric conditions),trying t...In this work,several ceria-zirconia based catalysts with very lo w(and equimolar) metal contents were prepared,characterised and tested for the CO oxidatio n reaction(under lean and stoichiometric conditions),trying to emulate those conditions found in a diesel oxidation catalyst(DOC) system from a diesel engine and those encountered under gasoline exhaust(λ=1).The metals chosen are Cu,Co,Ag and Pt(as a reliable benchmark).The results reveal enormous differences among reducibility and catalytic activity despite quite similar structural and textural properties of the catalysts,showing differences among dispersion(Ag-catalyst seems to present a low level of dispersion).This catalyst seems to be characterised,as well,by a strong electronic interaction between Ce and Ag centres which is suggested to yield an improved reducibility under H_(2)-TPR conditions.Nevertheless,the order in catalytic activity(Cu>Ag>Co≈Pt>>support) seems not to follow the order found in reducibility and the Cu-catalyst seems to be the most active independently on the reaction conditions,yielding nearly overlapped CO oxidation catalytic curves.Inte restingly,a stro ng correlation between the catalytic activity under the two conditions tested and the OSC values of the Ce_(0.8)Zr_(0.2)O_(2)-supported metal catalysts is found.Therefore,OSC parameter measured at 150℃ can be used as a relevant descriptor to evaluate the CO oxidation activity at low and medium conversions for the investigated catalysts,much better than the H_(2)-TPR measurements.展开更多
[Objective] This study was conducted to investigate heavy metal conditions in fruit producing area in Baise City, Guangxi Province. [Method] Heavy metal contents in 106 soil samples collected from fruit producing area...[Objective] This study was conducted to investigate heavy metal conditions in fruit producing area in Baise City, Guangxi Province. [Method] Heavy metal contents in 106 soil samples collected from fruit producing area in Youjiang District, Baise City, Guangxi Province were analyzed, and soil heavy metal pollution condition in this area was estimated applying single factor index method and Hakanson＇ potential ecological risk index method with reference to the second grade of National Soil Environmental Quality Standard and soil background values of this area. [Result] According to the second grade of National Soil Environmental Quality Standard, soil heavy metals in this fruit producing area is at the level of no pollution; and the total potential ecological risk pollution risk （RI） of soil heavy metals was 97.7, indicating no risk. [Conclusion] The fruit producing area in Baise City, Guangxi Province is free of heavy metal pollution.展开更多
With the increasing awareness of environmental protection, people’s concern of pollution issues arising. Vehicles, as the most important means of transportation, its exhaust emission has received considerable attenti...With the increasing awareness of environmental protection, people’s concern of pollution issues arising. Vehicles, as the most important means of transportation, its exhaust emission has received considerable attention. The catalytic converter is able to purify harmful substances in exhaust gas. The absolute content of precious metals in the catalytic converter dominates the exhaust gas purification effect. Accurate detection of precious metal content is of great significance for controlling the cost of catalysts, ensuring catalytic performance and recovering precious metals from spent catalysts. We herein summarized several instruments for precious metals content exploration, such as X-ray fluorescence spectrometer (XRF), atomic absorption spectrometer (AAS), inductively coupled plasma emission spectrometer (ICP) and spectrophotometer. In this thesis, the feasibility of using various devices for characterizing precious metal content in catalytic converters is analyzed and their strengths or weaknesses are elaborated.展开更多
[Objectives]To study the characteristics of soil heavy metal contents in facility agriculture of Guangxi and analyze its risks.[Methods]The heavy metal content of 30 surface soil samples taken from facility agricultur...[Objectives]To study the characteristics of soil heavy metal contents in facility agriculture of Guangxi and analyze its risks.[Methods]The heavy metal content of 30 surface soil samples taken from facility agriculture in Guangxi was analyzed.The status of soil heavy metal pollution in facility agriculture of Guangxi was evaluated by the single factor index method,geo-accumulation index method and Hakanson potential ecological risk index method with reference to the soil background value in Guangxi.[Results]Compared with the soil background value in Guangxi,the over-limit rates of heavy metals cadmium,lead,arsenic,chromium,mercury,copper and zinc in soil samples were 56.67%,56.67%,16.67%,30.00%,50.00%,60.00%and 80.00%,respectively.Compared with the screening values of the Soil Environmental Quality-Risk Control Standard for Soil Contamination of Agricultural Land(for trial implementation)(GB15618-2018),the overlimit rates of the heavy metals cadmium,arsenic,copper and zinc in the surface soil of agricultural facilities in Guangxi were 56.67%,10.00%,16.67%and 23.33%,respectively.Except for the average content of soil cadmium exceeding the screening value,the evaluation content of the other six soil heavy metals did not exceed the screening value.According to the evaluation results of the single factor pollution index method,the surface soil arsenic and chromium of the agricultural facilities in Guangxi belonged to the clean level,lead,mercury,and copper belonged to mild pollution,and cadmium and zinc belonged to moderate pollution.According to the evaluation results of the geo-accumulation index,the lead,arsenic,chromium and mercury in the surface soil of the agricultural facilities in Guangxi belonged to the pollution-free level,while the cadmium,copper and zinc belonged to the mild-moderate pollution.According to the evaluation results of the potential ecological risk index method,the potential ecological risks of the heavy metals of lead,arsenic,chromium,copper and zinc in the soil of agricultural facilities in Guangxi belonged to low potential ecological risk level,and the potential ecological risks of cadmium and mercury belonged to moderate risk level.The potential ecological risk index(RI)of the seven heavy metals in the soil was 132.46,which belonged to moderate potential ecological risk.The largest contribution of soil heavy metals to the potential ecological risk index was cadmium and mercury.[Conclusions]Taking the soil of facility agriculture in Guangxi as the object,this paper studied the characteristics of heavy metal content in facility agricultural soil and its risk assessment,in order to provide a scientific basis for facility soil heavy metal risk prevention and control and provide safe technology for facility agriculture.展开更多
According to the previous literature published since 1989, statistical analysis for reported data on the heavy metals in Chinese vegetable plantation soils was carried out systematically in this article. The purpose o...According to the previous literature published since 1989, statistical analysis for reported data on the heavy metals in Chinese vegetable plantation soils was carried out systematically in this article. The purpose of this investigation was to study the status of heavy metal content in vegetable land soils systematically through objective assessment to promote the development of vegetable production with high quality and efficiency. It is concluded that Zn, Cr, Cu had relatively high concentrations while the mean concentrations of toxic metals, As, Hg, Cd were 8.03, 0.12, 0.28 mg·kg^-1, respectively with comparatively low concentrations in Chinese vegetable land. Comparing to Clainese Soil Quality Criterion GB 15618- 1995 （6.5 〈 pH 〈 7.5）, about 24.1, 10.3, and 9.2% of the total samples was contaminated by Cd, Hg, and As, respectively, and the descending order of heavy metals was Cd 〉 Hg 〉 As 〉 Zn 〉 Cu 〉 Cr 〉 Pb. When compared among different regions, the more serious heavy metal contamination was found in the vegetable land of eastern China and the main contamination elements were Cd, Hg, and Zn. In the mid region, vegetable plantation land soil was mainly polluted by As and Cd, as well as by Hg, Zn, and Cu, to some extent. In the west region of China, Cd and As contamination was also observed to some degree, along with few soil samples exceeding the grade Ⅱ level of GB 15618-1995 （6.5 〈 pH 〈 7.5） for Cu, Cr, and Hg content. Compared to the five vegetable plantation land patterns, the highest concentration of As, Cd, Hg, and Zn occurred in the industrial/sewage irrigation vegetable land, especially for Hg with 2.36 mg·kg^-1 content averagely, which is 10.5-21.1 times higher than the other four types of vegetable lands. The highest concentration of Cn and Cr occurred in the greenhouse vegetable land soils, and urban vegetable land soil had the highest Pb content in comparison with the other types of vegetable plantation land patterns. By analyzing heavy metal content under different vegetable land patterns, it was found that soil in vegetable production base had relatively low heavy metal concentrations except for Pb with a slightly higher amount in the suburb area. The soil quality of common vegetable land was good with the lowest concentrations for most heavy metals. Under present utilization patterns of vegetable land, the soil quality in Chinese vegetable base land was good with comparatively low concentrations of heavy metals and mostly not exceeding the grade II level of Chinese Soil Quality Criterion GB 15618-1995 （6.5 〈 pH 〈 7.5）. However, comparatively serious contamination was found in industrial/sewage irrigation and suburb vegetable land soils.展开更多
Levels of seven metals （Mn, Cu, Zn, Pb, Cr, Cd, and Se） in the scalp hair of Daicun and Xiangtian inhabitants were determined by ICP-MS/AFS. Daicun, as an experimental site, is near Dexing Copper Mine, Jiangxi Provi...Levels of seven metals （Mn, Cu, Zn, Pb, Cr, Cd, and Se） in the scalp hair of Daicun and Xiangtian inhabitants were determined by ICP-MS/AFS. Daicun, as an experimental site, is near Dexing Copper Mine, Jiangxi Province, China, and exposed to mining pollution; Xiangtian, as a control site, is free from any mining and other industrial pollution. The heavy metal distribution in the scalp hair of the two diverse population segments exposed to different environments was discussed against the background of the heavy metal content of local plants, waters, and soils. The results show： 1） Levels ofCu, Zn, Pb, Cr, and Cd in the scalp hair of Daicun inhabitants were higher compared with Xiangtian counterparts which showed higher comparative levels of Se and Mn. But there were no significant differences of the levels of Cu and Zn in the hair samples between the two villages. In the hair of the inhabitants in the two villages, the levels for Se, Zn, and Cu were lower, while the level for Mn was higher, than the corresponding levels from other regions of the world. Compared with the standard issued by the Trace Element Research Council of China for Chinese inhabitants there were serious Se, Zn, Cu and Cr-deficiency phenomena in the hair samples from Daicun and Xiangtian. 2） Against the geological background of high levels ofZn, Cu, Se and Cr, there were deficiencies of Zn, Cu, Se and Cr in the hair samples of the Daictm population. This may have been caused by the distribution forms of the heavy metals in the soils, and antagonism among the elements. 3） Principal Component Analysis （PCA） and Cluster Analysis （CA） indicated that the origins of the heavy metals in the hair samples from the two villages had some differences as well as some similarities, this should be contributed mainly to the influence of the mining activities.展开更多
In blast furnace （BF） iron-making process, the hot metal silicon content was usually used to measure the quality of hot metal and to reflect the thermal state of BF. Principal component analysis （PCA） and partial ...In blast furnace （BF） iron-making process, the hot metal silicon content was usually used to measure the quality of hot metal and to reflect the thermal state of BF. Principal component analysis （PCA） and partial least- square （PLS） regression methods were used to predict the hot metal silicon content. Under the conditions of BF rela- tively stable situation, PCA and PLS regression models of hot metal silicon content utilizing data from Baotou Steel No. 6 BF were established, which provided the accuracy of 88.4% and 89.2%. PLS model used less variables and time than principal component analysis model, and it was simple to calculate. It is shown that the model gives good results and is helpful for practical production.展开更多
Microstructural evolution in weld metals was in-situ observed through utilizing a laser scanning confocal microscope at two cooling rates.The specimens with various nickel contents were adopted for the observation.In ...Microstructural evolution in weld metals was in-situ observed through utilizing a laser scanning confocal microscope at two cooling rates.The specimens with various nickel contents were adopted for the observation.In the specimen with low fraction of Ni（≤2 wt.%）,granular bainite microstructure（i.e.broad surface relief）transformation from intragranular nucleation site was in-situ observed,while,lath bainite microstructure originating from grain boundary of austenite was in-situ observed for specimens with high mass percentage of Ni（≥4 wt.%）.With increasing nickel content,the transformation temperature dropped.The prior austenite grain size was initially depressed and subsequently coarsened dramatically with the addition of Ni.The microstructure difference was ascribed to various nucleation sites and growth direction in the matrix.On account of those observations,not only the chemical component,cooling rate and microstructure were systematically correlated,but also the microstructural evolution was definite.展开更多
Some key operation variables influencing hot metal silicon content were selected, and time lag of each of them was obtained. A standardized fuzzy system model was developed to approach the random nonlinear dynamic sys...Some key operation variables influencing hot metal silicon content were selected, and time lag of each of them was obtained. A standardized fuzzy system model was developed to approach the random nonlinear dynamic system of the change of silicon content, forecast the change of silicon content and calculate silicon content. The prediction of hot metal silicon content is very successful with the data collected online from BF No. 1 at Laiwu Iron and Steel Group Co.展开更多
This study aimed to explore an analysis method for baicalin in Scutellaria baicalensis Georgi and make a reference for the analysis of the medicinal value of S. baicalensis cultivated in Jizhou District. The content o...This study aimed to explore an analysis method for baicalin in Scutellaria baicalensis Georgi and make a reference for the analysis of the medicinal value of S. baicalensis cultivated in Jizhou District. The content of baicalin in S. baicalensis cultivated in Jizhou District was determined using high-performance liquid chromatography( HPLC) to judge whether it met the requirements of Chinese Pharmacopoeia; and according to the requirements of the Chinese Pharmacopoeia of 2015 edition,the contents of heavy metals were determined by ICP-MS. The results showed that the contents of baicalin,Cr,Cu,As,Cd and Pb in S. baicalensis planted in Jizhou District were 14. 625 05%,11. 360,12. 830,0. 062 315,0. 025 715 and 0. 176 65 μg/g,respectively. The content of baicalin in S. baicalensis planted in Jizhou District was much higher than the standard( ≥ 9. 0%) of Chinese Pharmacopoeia of 2015 edition,and the contents of heavy metals were also below the limit( ≤20/1000 000) required by Chinese Pharmacopoeia of 2015 edition.展开更多
The time series data of silicon content in hot metal were identified to have the chaotic feature because of the positive maximum Lyapunov exponent, and then the time scales to predict future were estimated. Finally a ...The time series data of silicon content in hot metal were identified to have the chaotic feature because of the positive maximum Lyapunov exponent, and then the time scales to predict future were estimated. Finally a chaotic local-region model was constructed to predict silicon content in hot metal with good performance due to high hitting rate.展开更多
In recent years, most of domestic and foreign researches about heavy metal pollutions of metal mine mainly focus on water, soil and plants on the surface. There is lack of researches about heavy metal pollution in gro...In recent years, most of domestic and foreign researches about heavy metal pollutions of metal mine mainly focus on water, soil and plants on the surface. There is lack of researches about heavy metal pollution in groundwater of metal mine. In this research, a certain antimony mine area is selected as a typical study area. Also, the study about statistical characteristics of heavy metals in groundwater has been carried out. Furthermore, the interrelationships have been preliminarily discussed through related analysis, such as relevant analysis, cluster analysis and principle component analysis. The results show that: the excessive elements in groundwater of study area are Sb, As, Pb, Se, and Ni. The average mass concentration of Sb, As, and Pb is higher than that of drinking water standards(GB5749-2006). The concentration of most heavy metals in dry season is lower than or equal to that in wet season for groundwater. Zn is the only metal in groundwater showing a different pattern, the concentration of which in dry season is higher than that in wet season. Under the impacts of stratum leaching and absorption effect, the concentration of heavy metals(except Pb and Ba) in groundwater are lower than or equal to that in surface water. As and Se, the two heavy metals have a significant positive correlation, which shows the two elements might have gone through similar environmental geochemical effect. Also, the connection among Zn, Hg, Pb, and Mn is not obvious; therefore, the sources of those elements are quite different. In addition, the elements of Se and As have obvious positive interrelationship with elements of CO_3^(2-) and F^-. Also, the Pb has significant positive correlation with PO_4^(3-), H_2SiO_3 and oxygen consumption. The results of cluster analysis show that 9 different heavy metals in the study area can be divided into 3 categories: Zn, Cd, Mn, Hg, Cu, and Cr belong to the first category, Se and As belong to the second one, and the last category is Pb. Also, the principle component analysis divides 6 heavy metals(Zn, As, Hg, Pb, Mn, and Se) into 4 different principle components, which can be utilized to assess heavy metals pollution situations in groundwater. The reliability of this method is higher than 91%. Moreover, the research provides theory basis and models for establishing evaluation index system and exploring the evaluation method of heavy mental pollution in groundwater.展开更多
Feedstuff intake plays key role in impacting the yield and quality of milk. In this study, we discussed the contents of trace metal elements in cow milk impacted by different feedstuffs. We detected the contents of Pb...Feedstuff intake plays key role in impacting the yield and quality of milk. In this study, we discussed the contents of trace metal elements in cow milk impacted by different feedstuffs. We detected the contents of Pb, Cd, As, Cu, Mg, Ca, Fe and Zn in different feedstuffs and milk by atomic absorption spectrophotometry. The determinations of Pb, Cd and As contents were by graphite furnace A_AS and Cu, Mg, Ca, Fe and Zn was by flame atomic absorption spectrometry. The results showed that Pb, Cd, As and Cu presented in feedstuffs, but Pb, Cd and As were lowly detected in milk samples, and Cu was not detected in milk samples. The content of Mg in concentrates was lower than that in forages. However, the content of Mg in milk from concentrate feed was higher than that in forage feed. This suggested that the utilization of Mg in concentrate feed was higher than that in forage feed. The contents of Ca and Zn were opposite to Mg, and the utilization of Ca and Zn in forage feed was higher than that in concentrate feed. There was no obviously change law of Fe in different feedstuffs and milk samples. The relationship between the contents of trace metal elements in milk to feedstuffs would provide a theoretical basis for dairy farming. It would be useful for improving the milk yield and milk quality of dairy production.展开更多
There are some problems in steelmaking with hot metal containing low silicon content such as difficulty in slag formation, less slag for dephosphorization and slag adhesion on oxygen lance and hood. To overcome these ...There are some problems in steelmaking with hot metal containing low silicon content such as difficulty in slag formation, less slag for dephosphorization and slag adhesion on oxygen lance and hood. To overcome these problems, experiments wcrc conducted and some improvements were obtained, such as adding appropriate flux, increasing the lance position slightly during steelmaking and using effective multi-outlet nozzle. Moreover, to keep normal heating rate, the ore and scrap charge should be reduced due to less chemical heat input in steelmaking.展开更多
基金Supported by Fund for Key Laboratories in Guangxi Universities-Featured Resource Research and Development Laboratory of Northwest of Guangxi(GJKY 2010[6])Fund for Platform Built by University and Local Government or University and EnterpriseLocal Resource Protection and Utilization Engineering Center of Northwest of Guangxi(GJKY 2010[9])~~
文摘Objective] This study was conducted to evaluate the product quality and safety of Peristrophe roxburghiana_ col ected from different places in Hechi City, northwest of Gunagxi, so as to provide basic data for further development and uti-lization of the characteristic plant resource P. roxburghiana. [Method] Contents of 9 kinds of heavy metals including Cd, Mn, Pb, Zn and Cu in the herb were deter-mined by the method of wet digestion-flame atomic absorption spectrophotometry and atomic fluorescence spectrometry, respectively. [Results] Heavy metal contents of Cd, Mn, Pb, Fe, Cu, Zn, As, Hg and Se were 1.62-17.25, 8.93-142.53, 4.37-18.43, 103.7-242.81, 2.55-5.35, 85.40-146.30, 0.07-0.54, 0.00-0.08 and 0.00-0.47 mg/kg, respectively. According to the national food safety standards and Green Trade Standards of lmporting ＆amp; Exporting Medicinal plants ＆amp; Preparations, the heavy metal contents of the P. roxburghiana_samples col ected from different coun-ties in Hechi City exceeded standards or at the critical values. Among which, Cd, Pb and Zn contents of the samples are seriously higher than the standards. [Con-clusion] Therefore, the impact of soil heavy metal pol ution on the safety of edible plants in the northwest of Guangxi should be highly concerned.
基金Project supported by the Spanish Ministry of Science and Innovation/Research Spanish Agency (PID2019-105 542RB-100/AEI/10.13039/501100011033)the UE-FEDER funding and Generalitat Valenciana (CIPROM/2021/070)。
文摘In this work,several ceria-zirconia based catalysts with very lo w(and equimolar) metal contents were prepared,characterised and tested for the CO oxidatio n reaction(under lean and stoichiometric conditions),trying to emulate those conditions found in a diesel oxidation catalyst(DOC) system from a diesel engine and those encountered under gasoline exhaust(λ=1).The metals chosen are Cu,Co,Ag and Pt(as a reliable benchmark).The results reveal enormous differences among reducibility and catalytic activity despite quite similar structural and textural properties of the catalysts,showing differences among dispersion(Ag-catalyst seems to present a low level of dispersion).This catalyst seems to be characterised,as well,by a strong electronic interaction between Ce and Ag centres which is suggested to yield an improved reducibility under H_(2)-TPR conditions.Nevertheless,the order in catalytic activity(Cu>Ag>Co≈Pt>>support) seems not to follow the order found in reducibility and the Cu-catalyst seems to be the most active independently on the reaction conditions,yielding nearly overlapped CO oxidation catalytic curves.Inte restingly,a stro ng correlation between the catalytic activity under the two conditions tested and the OSC values of the Ce_(0.8)Zr_(0.2)O_(2)-supported metal catalysts is found.Therefore,OSC parameter measured at 150℃ can be used as a relevant descriptor to evaluate the CO oxidation activity at low and medium conversions for the investigated catalysts,much better than the H_(2)-TPR measurements.
基金Supported by Special Fund for Basal Scientific Research of Guangxi Academy of Agricultural Science(GNK2015JZ29,GNK2015YT32)~~
文摘[Objective] This study was conducted to investigate heavy metal conditions in fruit producing area in Baise City, Guangxi Province. [Method] Heavy metal contents in 106 soil samples collected from fruit producing area in Youjiang District, Baise City, Guangxi Province were analyzed, and soil heavy metal pollution condition in this area was estimated applying single factor index method and Hakanson＇ potential ecological risk index method with reference to the second grade of National Soil Environmental Quality Standard and soil background values of this area. [Result] According to the second grade of National Soil Environmental Quality Standard, soil heavy metals in this fruit producing area is at the level of no pollution; and the total potential ecological risk pollution risk （RI） of soil heavy metals was 97.7, indicating no risk. [Conclusion] The fruit producing area in Baise City, Guangxi Province is free of heavy metal pollution.
文摘With the increasing awareness of environmental protection, people’s concern of pollution issues arising. Vehicles, as the most important means of transportation, its exhaust emission has received considerable attention. The catalytic converter is able to purify harmful substances in exhaust gas. The absolute content of precious metals in the catalytic converter dominates the exhaust gas purification effect. Accurate detection of precious metal content is of great significance for controlling the cost of catalysts, ensuring catalytic performance and recovering precious metals from spent catalysts. We herein summarized several instruments for precious metals content exploration, such as X-ray fluorescence spectrometer (XRF), atomic absorption spectrometer (AAS), inductively coupled plasma emission spectrometer (ICP) and spectrophotometer. In this thesis, the feasibility of using various devices for characterizing precious metal content in catalytic converters is analyzed and their strengths or weaknesses are elaborated.
基金Supported by Key Research and Development Program of Guangxi(Gui Ke AB18221096)Fund of Guangxi Academy of Agricultural Sciences(2019ZX121Gui Nong Ke 2020ZX03)
文摘[Objectives]To study the characteristics of soil heavy metal contents in facility agriculture of Guangxi and analyze its risks.[Methods]The heavy metal content of 30 surface soil samples taken from facility agriculture in Guangxi was analyzed.The status of soil heavy metal pollution in facility agriculture of Guangxi was evaluated by the single factor index method,geo-accumulation index method and Hakanson potential ecological risk index method with reference to the soil background value in Guangxi.[Results]Compared with the soil background value in Guangxi,the over-limit rates of heavy metals cadmium,lead,arsenic,chromium,mercury,copper and zinc in soil samples were 56.67%,56.67%,16.67%,30.00%,50.00%,60.00%and 80.00%,respectively.Compared with the screening values of the Soil Environmental Quality-Risk Control Standard for Soil Contamination of Agricultural Land(for trial implementation)(GB15618-2018),the overlimit rates of the heavy metals cadmium,arsenic,copper and zinc in the surface soil of agricultural facilities in Guangxi were 56.67%,10.00%,16.67%and 23.33%,respectively.Except for the average content of soil cadmium exceeding the screening value,the evaluation content of the other six soil heavy metals did not exceed the screening value.According to the evaluation results of the single factor pollution index method,the surface soil arsenic and chromium of the agricultural facilities in Guangxi belonged to the clean level,lead,mercury,and copper belonged to mild pollution,and cadmium and zinc belonged to moderate pollution.According to the evaluation results of the geo-accumulation index,the lead,arsenic,chromium and mercury in the surface soil of the agricultural facilities in Guangxi belonged to the pollution-free level,while the cadmium,copper and zinc belonged to the mild-moderate pollution.According to the evaluation results of the potential ecological risk index method,the potential ecological risks of the heavy metals of lead,arsenic,chromium,copper and zinc in the soil of agricultural facilities in Guangxi belonged to low potential ecological risk level,and the potential ecological risks of cadmium and mercury belonged to moderate risk level.The potential ecological risk index(RI)of the seven heavy metals in the soil was 132.46,which belonged to moderate potential ecological risk.The largest contribution of soil heavy metals to the potential ecological risk index was cadmium and mercury.[Conclusions]Taking the soil of facility agriculture in Guangxi as the object,this paper studied the characteristics of heavy metal content in facility agricultural soil and its risk assessment,in order to provide a scientific basis for facility soil heavy metal risk prevention and control and provide safe technology for facility agriculture.
基金the National Key Technology R&D Program during the 11th Five-Year Plan period (2006BAD05B01)the project of Standards on Heavy Metal Contamination of Farmlands (2007-2009)Special Public Welfare Fund of Basic Scientific Research Service Spends for Research Institute/Academy supported by China Central Government
文摘According to the previous literature published since 1989, statistical analysis for reported data on the heavy metals in Chinese vegetable plantation soils was carried out systematically in this article. The purpose of this investigation was to study the status of heavy metal content in vegetable land soils systematically through objective assessment to promote the development of vegetable production with high quality and efficiency. It is concluded that Zn, Cr, Cu had relatively high concentrations while the mean concentrations of toxic metals, As, Hg, Cd were 8.03, 0.12, 0.28 mg·kg^-1, respectively with comparatively low concentrations in Chinese vegetable land. Comparing to Clainese Soil Quality Criterion GB 15618- 1995 （6.5 〈 pH 〈 7.5）, about 24.1, 10.3, and 9.2% of the total samples was contaminated by Cd, Hg, and As, respectively, and the descending order of heavy metals was Cd 〉 Hg 〉 As 〉 Zn 〉 Cu 〉 Cr 〉 Pb. When compared among different regions, the more serious heavy metal contamination was found in the vegetable land of eastern China and the main contamination elements were Cd, Hg, and Zn. In the mid region, vegetable plantation land soil was mainly polluted by As and Cd, as well as by Hg, Zn, and Cu, to some extent. In the west region of China, Cd and As contamination was also observed to some degree, along with few soil samples exceeding the grade Ⅱ level of GB 15618-1995 （6.5 〈 pH 〈 7.5） for Cu, Cr, and Hg content. Compared to the five vegetable plantation land patterns, the highest concentration of As, Cd, Hg, and Zn occurred in the industrial/sewage irrigation vegetable land, especially for Hg with 2.36 mg·kg^-1 content averagely, which is 10.5-21.1 times higher than the other four types of vegetable lands. The highest concentration of Cn and Cr occurred in the greenhouse vegetable land soils, and urban vegetable land soil had the highest Pb content in comparison with the other types of vegetable plantation land patterns. By analyzing heavy metal content under different vegetable land patterns, it was found that soil in vegetable production base had relatively low heavy metal concentrations except for Pb with a slightly higher amount in the suburb area. The soil quality of common vegetable land was good with the lowest concentrations for most heavy metals. Under present utilization patterns of vegetable land, the soil quality in Chinese vegetable base land was good with comparatively low concentrations of heavy metals and mostly not exceeding the grade II level of Chinese Soil Quality Criterion GB 15618-1995 （6.5 〈 pH 〈 7.5）. However, comparatively serious contamination was found in industrial/sewage irrigation and suburb vegetable land soils.
基金supported by Management of Central Public-interest Scientific Institution Basal Research Fund (Grant Nos. K0905, K1020)National Key Technologies R & D Program (Grant Nos. 2006BAB01A07, 2006BAB01B05)
文摘Levels of seven metals （Mn, Cu, Zn, Pb, Cr, Cd, and Se） in the scalp hair of Daicun and Xiangtian inhabitants were determined by ICP-MS/AFS. Daicun, as an experimental site, is near Dexing Copper Mine, Jiangxi Province, China, and exposed to mining pollution; Xiangtian, as a control site, is free from any mining and other industrial pollution. The heavy metal distribution in the scalp hair of the two diverse population segments exposed to different environments was discussed against the background of the heavy metal content of local plants, waters, and soils. The results show： 1） Levels ofCu, Zn, Pb, Cr, and Cd in the scalp hair of Daicun inhabitants were higher compared with Xiangtian counterparts which showed higher comparative levels of Se and Mn. But there were no significant differences of the levels of Cu and Zn in the hair samples between the two villages. In the hair of the inhabitants in the two villages, the levels for Se, Zn, and Cu were lower, while the level for Mn was higher, than the corresponding levels from other regions of the world. Compared with the standard issued by the Trace Element Research Council of China for Chinese inhabitants there were serious Se, Zn, Cu and Cr-deficiency phenomena in the hair samples from Daicun and Xiangtian. 2） Against the geological background of high levels ofZn, Cu, Se and Cr, there were deficiencies of Zn, Cu, Se and Cr in the hair samples of the Daictm population. This may have been caused by the distribution forms of the heavy metals in the soils, and antagonism among the elements. 3） Principal Component Analysis （PCA） and Cluster Analysis （CA） indicated that the origins of the heavy metals in the hair samples from the two villages had some differences as well as some similarities, this should be contributed mainly to the influence of the mining activities.
基金Item Sponsored by National Natural Science Foundation of China(51064019)Natural Science Foundation of Inner Mongolia of China(20010MS0911,NJzy08075)
文摘In blast furnace （BF） iron-making process, the hot metal silicon content was usually used to measure the quality of hot metal and to reflect the thermal state of BF. Principal component analysis （PCA） and partial least- square （PLS） regression methods were used to predict the hot metal silicon content. Under the conditions of BF rela- tively stable situation, PCA and PLS regression models of hot metal silicon content utilizing data from Baotou Steel No. 6 BF were established, which provided the accuracy of 88.4% and 89.2%. PLS model used less variables and time than principal component analysis model, and it was simple to calculate. It is shown that the model gives good results and is helpful for practical production.
基金financially supported by National Natural Science Foundation of China (No.51675255)Pre-research of National Basic Research Program of China(2014CB660810)the Rose Willow Outstanding Individual Programs of Lanzhou University of Technology(J201203)
文摘Microstructural evolution in weld metals was in-situ observed through utilizing a laser scanning confocal microscope at two cooling rates.The specimens with various nickel contents were adopted for the observation.In the specimen with low fraction of Ni（≤2 wt.%）,granular bainite microstructure（i.e.broad surface relief）transformation from intragranular nucleation site was in-situ observed,while,lath bainite microstructure originating from grain boundary of austenite was in-situ observed for specimens with high mass percentage of Ni（≥4 wt.%）.With increasing nickel content,the transformation temperature dropped.The prior austenite grain size was initially depressed and subsequently coarsened dramatically with the addition of Ni.The microstructure difference was ascribed to various nucleation sites and growth direction in the matrix.On account of those observations,not only the chemical component,cooling rate and microstructure were systematically correlated,but also the microstructural evolution was definite.
文摘Some key operation variables influencing hot metal silicon content were selected, and time lag of each of them was obtained. A standardized fuzzy system model was developed to approach the random nonlinear dynamic system of the change of silicon content, forecast the change of silicon content and calculate silicon content. The prediction of hot metal silicon content is very successful with the data collected online from BF No. 1 at Laiwu Iron and Steel Group Co.
基金Supported by Tianjin Science and Technology Plan Project(16PTZSTG-00020)Talents Project of Tianjin Agricultural University.Tianjin Science and Technology Plan Project(17JCYBJC29800)Various Talent Funding Project of Tianjin Agricultural University(J01009030702)
文摘This study aimed to explore an analysis method for baicalin in Scutellaria baicalensis Georgi and make a reference for the analysis of the medicinal value of S. baicalensis cultivated in Jizhou District. The content of baicalin in S. baicalensis cultivated in Jizhou District was determined using high-performance liquid chromatography( HPLC) to judge whether it met the requirements of Chinese Pharmacopoeia; and according to the requirements of the Chinese Pharmacopoeia of 2015 edition,the contents of heavy metals were determined by ICP-MS. The results showed that the contents of baicalin,Cr,Cu,As,Cd and Pb in S. baicalensis planted in Jizhou District were 14. 625 05%,11. 360,12. 830,0. 062 315,0. 025 715 and 0. 176 65 μg/g,respectively. The content of baicalin in S. baicalensis planted in Jizhou District was much higher than the standard( ≥ 9. 0%) of Chinese Pharmacopoeia of 2015 edition,and the contents of heavy metals were also below the limit( ≤20/1000 000) required by Chinese Pharmacopoeia of 2015 edition.
文摘The time series data of silicon content in hot metal were identified to have the chaotic feature because of the positive maximum Lyapunov exponent, and then the time scales to predict future were estimated. Finally a chaotic local-region model was constructed to predict silicon content in hot metal with good performance due to high hitting rate.
基金supported by Homeland Resource Non-Profit Research Special Funding Project(No.200911036)
文摘In recent years, most of domestic and foreign researches about heavy metal pollutions of metal mine mainly focus on water, soil and plants on the surface. There is lack of researches about heavy metal pollution in groundwater of metal mine. In this research, a certain antimony mine area is selected as a typical study area. Also, the study about statistical characteristics of heavy metals in groundwater has been carried out. Furthermore, the interrelationships have been preliminarily discussed through related analysis, such as relevant analysis, cluster analysis and principle component analysis. The results show that: the excessive elements in groundwater of study area are Sb, As, Pb, Se, and Ni. The average mass concentration of Sb, As, and Pb is higher than that of drinking water standards(GB5749-2006). The concentration of most heavy metals in dry season is lower than or equal to that in wet season for groundwater. Zn is the only metal in groundwater showing a different pattern, the concentration of which in dry season is higher than that in wet season. Under the impacts of stratum leaching and absorption effect, the concentration of heavy metals(except Pb and Ba) in groundwater are lower than or equal to that in surface water. As and Se, the two heavy metals have a significant positive correlation, which shows the two elements might have gone through similar environmental geochemical effect. Also, the connection among Zn, Hg, Pb, and Mn is not obvious; therefore, the sources of those elements are quite different. In addition, the elements of Se and As have obvious positive interrelationship with elements of CO_3^(2-) and F^-. Also, the Pb has significant positive correlation with PO_4^(3-), H_2SiO_3 and oxygen consumption. The results of cluster analysis show that 9 different heavy metals in the study area can be divided into 3 categories: Zn, Cd, Mn, Hg, Cu, and Cr belong to the first category, Se and As belong to the second one, and the last category is Pb. Also, the principle component analysis divides 6 heavy metals(Zn, As, Hg, Pb, Mn, and Se) into 4 different principle components, which can be utilized to assess heavy metals pollution situations in groundwater. The reliability of this method is higher than 91%. Moreover, the research provides theory basis and models for establishing evaluation index system and exploring the evaluation method of heavy mental pollution in groundwater.
文摘Feedstuff intake plays key role in impacting the yield and quality of milk. In this study, we discussed the contents of trace metal elements in cow milk impacted by different feedstuffs. We detected the contents of Pb, Cd, As, Cu, Mg, Ca, Fe and Zn in different feedstuffs and milk by atomic absorption spectrophotometry. The determinations of Pb, Cd and As contents were by graphite furnace A_AS and Cu, Mg, Ca, Fe and Zn was by flame atomic absorption spectrometry. The results showed that Pb, Cd, As and Cu presented in feedstuffs, but Pb, Cd and As were lowly detected in milk samples, and Cu was not detected in milk samples. The content of Mg in concentrates was lower than that in forages. However, the content of Mg in milk from concentrate feed was higher than that in forage feed. This suggested that the utilization of Mg in concentrate feed was higher than that in forage feed. The contents of Ca and Zn were opposite to Mg, and the utilization of Ca and Zn in forage feed was higher than that in concentrate feed. There was no obviously change law of Fe in different feedstuffs and milk samples. The relationship between the contents of trace metal elements in milk to feedstuffs would provide a theoretical basis for dairy farming. It would be useful for improving the milk yield and milk quality of dairy production.
文摘There are some problems in steelmaking with hot metal containing low silicon content such as difficulty in slag formation, less slag for dephosphorization and slag adhesion on oxygen lance and hood. To overcome these problems, experiments wcrc conducted and some improvements were obtained, such as adding appropriate flux, increasing the lance position slightly during steelmaking and using effective multi-outlet nozzle. Moreover, to keep normal heating rate, the ore and scrap charge should be reduced due to less chemical heat input in steelmaking.
