Rational design of extractant structure to improve the extraction and separation capacity of rare earth elements(REEs)is a long-standing challenge.Herein,a new strategy was proposed to improve the stability of the che...Rational design of extractant structure to improve the extraction and separation capacity of rare earth elements(REEs)is a long-standing challenge.Herein,a new strategy was proposed to improve the stability of the chelating structure formed by malonamide and REEs.The stability of the chelating structure is greatly improved by using a double-ring framework structure which makes the two carbonyl groups of malonamide unable to rotate freely and both of them point to the metal ion position.Three benzyl groups were used to construct the hydrophobicity of the extractant and the organic shell of the extracted species.Tribenzylhexahydro-pyrrolo-pyridine-dione(THPPD)was designed and synthesized.The structure reduces the energy consumed by rotating carbonyl group in the coordination with metal ions and then improves the extraction ability of extractant.The crystal structure was preorganized as expected,with the two carbonyls pointing in a favorable coordination direction to the structural complement of the metal ion.The extraction behaviors of REEs with THPPD in a nitric acid medium were studied.Compared with N,N’-dibenzyl-N,N’-dimethylmalonamide(DBDM-MA)with a chain structure,the extraction capacity of THPPD is 360 times higher than that of DBDM-MA at 5.0 mol/L sodium nitrate.Furthermore,the binding energy and Gibbs free energy were investigated by density functional theory(DFT)in conjunction with the B3LYP.The theoretical results show that THPPD has more effective interaction with Pr(NO_(3))3 than DBDM-MA.The construction of chelating groups conformation is a worthy direction to improve the coordination ability and even selectivity of extractant.展开更多
Fashion shopping in WeChat(微信)Moments(朋友圈)has become an important new channel because of the rapid development and broad application of the smart phone technology.The purpose of the paper is to test a model deali...Fashion shopping in WeChat(微信)Moments(朋友圈)has become an important new channel because of the rapid development and broad application of the smart phone technology.The purpose of the paper is to test a model dealing with direct effects of shopping values on purchase intention.The research model was tested using smart phone in a survey of 276 respondents.The results as follows:First,higher shopping value perceived consumers have more purchase intention of fashion products in WeChat.Second,utilitarian shopping value play more positive impact on purchase intention than hedonic shopping value.Additional managerial implications are discussed.展开更多
Online shopping has become an important new channel because of its rapid development and broad application of the Internettechnology. As consumer information search and release gradually shift from offline to online, ...Online shopping has become an important new channel because of its rapid development and broad application of the Internettechnology. As consumer information search and release gradually shift from offline to online, online reviews of products havebecome more valuable. Research shows that most online shoppers view online reviews from product users before purchasing. Asone of the most important forms of spreading awareness, online product reviews has an increasing impact on customer purchasedecisions and has gradually become an urgent issue in network marketing research. This phenomenon impels businesses to realizethat online reviews significantly affect trading volume. Businesses have attempted to manipulate online reviews by providing asignificant number of positive comments that could lead to consumer confidence and purchase of products. Internet users inChina are more interested in reading negative comments compared with the rest of the global Internet users. Thus, the effects ofstructural characteristics of potential customers, negative attitudes, and behavioral intentions have not yet aroused global concernbecause this phenomenon has been limited to the local scale.Based on literature, the main objective of negative online reviews is the positioning of fashion products. The perception ofnegative online reviews, purchase attitudes, and behaviors are the factors considered in the present study. Negative online reviewsof clothing and accessories sold online and their influence on consumer purchase intention and attitudes are analyzed. The studyaims to confirm that negative online reviews have an effect on consumer purchase intention, attitudes, and behaviors. Moreover,buying attitudes influence behavior intention.展开更多
As the Economic Reform and Opening Up processes continue to develop intensively in China, the tourism industry has attained aconsiderable scale and has developed rapidly after nearly 20 years of progress. In recent ye...As the Economic Reform and Opening Up processes continue to develop intensively in China, the tourism industry has attained aconsiderable scale and has developed rapidly after nearly 20 years of progress. In recent years, leisure tourism has become arapidly growing sunrise industry as a result of the gradual increase in Chinese income. Such increase became evident in the 80sand 90s, when consumption attitudes changed. Furthermore, the Internet and e-commerce have also grown very quickly.Consequently, the natural integration of tourism and e-commerce occurred. From 2004 to 2014, e-commerce websites devoted toChinese tourism emerged continuously, and the industry scale expanded unceasingly. Gradually, e-commerce captured thetraditional offline travel agency＇s market share. The pattern of industrial upgrading in tourism has become the current trend.However, some problems and contradictions also exist in the development of e-commerce in the tourism industry, and manytourism websites that once flourished had their ups and downs and even declined amidst the competition. This decline has beenbrought about by the failure of some tourism enterprises to grasp the purchase intention of customers and to enhance their corecompetitiveness according to the actual demands of their users. Thus, this empirical study aims to provide a better marketingstrategy policy for online travel managers. To attain this aim, questionnaire survey methods were used in combination with theanalysis of the related characteristics of online travel products.展开更多
Continental silicate weathering acts as a crucial negative feedback mechanism for removing atmospheric CO_(2) and maintaining Earth's long-term climate stability.However,quantifying continental silicate weathering...Continental silicate weathering acts as a crucial negative feedback mechanism for removing atmospheric CO_(2) and maintaining Earth's long-term climate stability.However,quantifying continental silicate weathering rates and fluxes continues to pose a fundamental challenge in Earth system science.This study utilizes the GEOCLIM carbon cycle model,which integrates modern high-resolution(0.1°×0.1°)datasets on surface temperature,runoff,topography,and lithology to model the spatial distribution of global silicate weathering fluxes.Results indicate a strong correlation between modeled basin-scale outputs and hydrological observations,with weathering rates falling within consistent error margins.Silicate weathering fluxes exhibit distinct latitudinal patterns,with the highest values concentrated within 30°of the equator,accounting for 76.9%of the global total.Continental contributions differ significantly,with Asian river basins representing 36.9%of global fluxes,primarily from Southeast Asia(17.4%),South Asia(8.2%),and East Asia(6.6%).They are followed by South America(29.2%)and Africa(21.7%).Tectonically active regions contribute 21.9%of global silicate weathering,while stable regions account for 72.6%.Multivariate regression analyses using RF and XGBoost machine learning algorithms identify runoff as the primary controlling factor of weathering on a global scale.Weathering in stable regions is jointly regulated by runoff and erosion rates,whereas temperature is the prevailing factor in tectonically active zones.The GEOCLIM model offers a robust framework for quantifying continental weathering processes.Future studies should incorporate organic carbon oxidation,burial,and sulfide oxidation dynamics to clarify carbon cycle interactions and reveal climate-dependent mechanisms for weathering responses and feedback.展开更多
基金Project supported by the National Natural Science Foundation of China(21876062)Shandong Provincial Natural Science Foundation(ZR2022QB067)。
文摘Rational design of extractant structure to improve the extraction and separation capacity of rare earth elements(REEs)is a long-standing challenge.Herein,a new strategy was proposed to improve the stability of the chelating structure formed by malonamide and REEs.The stability of the chelating structure is greatly improved by using a double-ring framework structure which makes the two carbonyl groups of malonamide unable to rotate freely and both of them point to the metal ion position.Three benzyl groups were used to construct the hydrophobicity of the extractant and the organic shell of the extracted species.Tribenzylhexahydro-pyrrolo-pyridine-dione(THPPD)was designed and synthesized.The structure reduces the energy consumed by rotating carbonyl group in the coordination with metal ions and then improves the extraction ability of extractant.The crystal structure was preorganized as expected,with the two carbonyls pointing in a favorable coordination direction to the structural complement of the metal ion.The extraction behaviors of REEs with THPPD in a nitric acid medium were studied.Compared with N,N’-dibenzyl-N,N’-dimethylmalonamide(DBDM-MA)with a chain structure,the extraction capacity of THPPD is 360 times higher than that of DBDM-MA at 5.0 mol/L sodium nitrate.Furthermore,the binding energy and Gibbs free energy were investigated by density functional theory(DFT)in conjunction with the B3LYP.The theoretical results show that THPPD has more effective interaction with Pr(NO_(3))3 than DBDM-MA.The construction of chelating groups conformation is a worthy direction to improve the coordination ability and even selectivity of extractant.
文摘Fashion shopping in WeChat(微信)Moments(朋友圈)has become an important new channel because of the rapid development and broad application of the smart phone technology.The purpose of the paper is to test a model dealing with direct effects of shopping values on purchase intention.The research model was tested using smart phone in a survey of 276 respondents.The results as follows:First,higher shopping value perceived consumers have more purchase intention of fashion products in WeChat.Second,utilitarian shopping value play more positive impact on purchase intention than hedonic shopping value.Additional managerial implications are discussed.
文摘Online shopping has become an important new channel because of its rapid development and broad application of the Internettechnology. As consumer information search and release gradually shift from offline to online, online reviews of products havebecome more valuable. Research shows that most online shoppers view online reviews from product users before purchasing. Asone of the most important forms of spreading awareness, online product reviews has an increasing impact on customer purchasedecisions and has gradually become an urgent issue in network marketing research. This phenomenon impels businesses to realizethat online reviews significantly affect trading volume. Businesses have attempted to manipulate online reviews by providing asignificant number of positive comments that could lead to consumer confidence and purchase of products. Internet users inChina are more interested in reading negative comments compared with the rest of the global Internet users. Thus, the effects ofstructural characteristics of potential customers, negative attitudes, and behavioral intentions have not yet aroused global concernbecause this phenomenon has been limited to the local scale.Based on literature, the main objective of negative online reviews is the positioning of fashion products. The perception ofnegative online reviews, purchase attitudes, and behaviors are the factors considered in the present study. Negative online reviewsof clothing and accessories sold online and their influence on consumer purchase intention and attitudes are analyzed. The studyaims to confirm that negative online reviews have an effect on consumer purchase intention, attitudes, and behaviors. Moreover,buying attitudes influence behavior intention.
文摘As the Economic Reform and Opening Up processes continue to develop intensively in China, the tourism industry has attained aconsiderable scale and has developed rapidly after nearly 20 years of progress. In recent years, leisure tourism has become arapidly growing sunrise industry as a result of the gradual increase in Chinese income. Such increase became evident in the 80sand 90s, when consumption attitudes changed. Furthermore, the Internet and e-commerce have also grown very quickly.Consequently, the natural integration of tourism and e-commerce occurred. From 2004 to 2014, e-commerce websites devoted toChinese tourism emerged continuously, and the industry scale expanded unceasingly. Gradually, e-commerce captured thetraditional offline travel agency＇s market share. The pattern of industrial upgrading in tourism has become the current trend.However, some problems and contradictions also exist in the development of e-commerce in the tourism industry, and manytourism websites that once flourished had their ups and downs and even declined amidst the competition. This decline has beenbrought about by the failure of some tourism enterprises to grasp the purchase intention of customers and to enhance their corecompetitiveness according to the actual demands of their users. Thus, this empirical study aims to provide a better marketingstrategy policy for online travel managers. To attain this aim, questionnaire survey methods were used in combination with theanalysis of the related characteristics of online travel products.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFF0800504)the Major Program of the National Natural Science Foundation of China(Grant No.41991324)the Major Research Plan of the National Natural Science Foundation of China(Grant No.92479106)。
文摘Continental silicate weathering acts as a crucial negative feedback mechanism for removing atmospheric CO_(2) and maintaining Earth's long-term climate stability.However,quantifying continental silicate weathering rates and fluxes continues to pose a fundamental challenge in Earth system science.This study utilizes the GEOCLIM carbon cycle model,which integrates modern high-resolution(0.1°×0.1°)datasets on surface temperature,runoff,topography,and lithology to model the spatial distribution of global silicate weathering fluxes.Results indicate a strong correlation between modeled basin-scale outputs and hydrological observations,with weathering rates falling within consistent error margins.Silicate weathering fluxes exhibit distinct latitudinal patterns,with the highest values concentrated within 30°of the equator,accounting for 76.9%of the global total.Continental contributions differ significantly,with Asian river basins representing 36.9%of global fluxes,primarily from Southeast Asia(17.4%),South Asia(8.2%),and East Asia(6.6%).They are followed by South America(29.2%)and Africa(21.7%).Tectonically active regions contribute 21.9%of global silicate weathering,while stable regions account for 72.6%.Multivariate regression analyses using RF and XGBoost machine learning algorithms identify runoff as the primary controlling factor of weathering on a global scale.Weathering in stable regions is jointly regulated by runoff and erosion rates,whereas temperature is the prevailing factor in tectonically active zones.The GEOCLIM model offers a robust framework for quantifying continental weathering processes.Future studies should incorporate organic carbon oxidation,burial,and sulfide oxidation dynamics to clarify carbon cycle interactions and reveal climate-dependent mechanisms for weathering responses and feedback.
