Extraction of theanine from waste liquid of tea polyphenol production was studied in aqueous surfactanttwo-phase system (ASTP) with cationic surfactant (CTAB) and anionic surfactant (SDS). Results indicate that ...Extraction of theanine from waste liquid of tea polyphenol production was studied in aqueous surfactanttwo-phase system (ASTP) with cationic surfactant (CTAB) and anionic surfactant (SDS). Results indicate that the region of ASTP is narrow and there is only a two-phase region of cationic surfactant. The increase in concentrations of NaBr and Na2SO4 are beneficial to the formation of ASTP. Theanine concentration in the bottom phase increases with increasing concentration of theanine, whereas the Partition coefficient and extraction rate only change a littlewhen the concentration of theanine is above 0.2 g.L-'. With the increase of SDS concentration, the phase ratio and the partition coefficient decrease, while the extraction efficiency of theanine increases and the concentration of theanine changes a little in the range from 2.4/7.5 to 2.8/7.2 for SDS/CTAB ratio. The temperature has a notable ef- fect on the concentration of theanine in the bottom phase, partition coefficient and extraction rate of theanine. The increase of waste liquid decreases the phase ratio, increases the concentration and extraction rate of theanine in the bottom ohase, since the orotein and the saccharide enter the bottom nhase with theanine.展开更多
The quantities of gas released into the environment during the extraction and processing of crude oil,by flaring,constitute a vast source of mineral wealth which can be used to produce other useful products.The proces...The quantities of gas released into the environment during the extraction and processing of crude oil,by flaring,constitute a vast source of mineral wealth which can be used to produce other useful products.The processes studied in this paper,as alternatives to the above problem,are the ones used in Shell Pearl Qatar project and Oryx GTL project.Both projects produce liquid fuels,mainly naphtha and diesel,in addition to more special fuel such as kerosene.This paper is a feasibility study of a project that makes use of the flare gas from the State of Texas,U.S.A.,as a feedstock to a process similar to either Shell Pearl Qatar project,or Oryx GTL project.The objective of this study is to determine the price range for crude oil over which an investment to similar projects can be profitable.An MS Excel Model was developed in order to perform calculations having as a variable the crude oil price and taking into account all the process and project’s financial data.The results of this model showed that a project similar to Shell Pearl Qatar remains profitable in crude oil price above$57.76/barrel,while a project similar to Oryx GTL remains viable for crude oil price over$31.4/bbl.In the price range$55-$60/barrel,the payout of the corresponding to Shell Pearl Qatar project will be in about 15.2 years and 3.3 years for a project similar to Oryx GTL.Finally,using the financial principles of this study we can apply them to any process in order to determine under what conditions will remain viable.展开更多
The effect of cooling liquid used for heat exchangers on the Cu alloy corrosion products has been examined using potential-time measurements under applied current condition (anodizing), potentiodynamic polarization, X...The effect of cooling liquid used for heat exchangers on the Cu alloy corrosion products has been examined using potential-time measurements under applied current condition (anodizing), potentiodynamic polarization, X-ray diffraction (XRD) and infrared spectroscopy (IR) The corrosion products formed on the Cu alloy surface during anodizing, are Cu2O, Cu2(OH)3Cl, and Cu2S. NaCl is detected in the corrosion products. The film formation depends on the applied current and the shift of potential to nobler direction indicates its formation progress.展开更多
The Karachi Port of Pakistan is a deep natural sea port with a history of 150 years. The Port has an 11 km long approach channel decaracted with buoys for proriding safe navigation of 75,000 DWT tankers,modern contain...The Karachi Port of Pakistan is a deep natural sea port with a history of 150 years. The Port has an 11 km long approach channel decaracted with buoys for proriding safe navigation of 75,000 DWT tankers,modern container vessels,bulk Karachi Port is the premier port of Pakistan and handles over 85 percent of the whole dry gen-展开更多
Efforts to provide alternative resources and technologies for producing liquid fuel have recently been intensified.Different levels of dependence on oil imports and carbon prices have a significant impact on the compo...Efforts to provide alternative resources and technologies for producing liquid fuel have recently been intensified.Different levels of dependence on oil imports and carbon prices have a significant impact on the composition of the cost-minimizing portfolio of technologies.Considering such factors,how should China plan its future liquid fuel industry?The model for supporting the technology portfolio and capacity configuration that minimizes the total system cost until 2045 is described in this study.The results obtained for different carbon prices and levels of dependence on oil import indicate that the oil-to-liquid fuel(OTL)will remain dominant in China's liquid fuel industry over the next three decades.If the carbon price is low,the coal-to-liquid fuel(CTL)process is competitive.For a high carbon price,the biomass-to-liquid fuel(BTL)technology expands more rapidly.The results also reveal that developing the BTL and CTL can effectively reduce the oil-import dependency;moreover,a high carbon price can lead to the CTL being replaced with the low-carbon technology(e.g.,BTL).Improvement in energy raw material conversion and application of CO_(2) removal technologies are also effective methods to control carbon emissions for achieving the carbon emission goals and ultimately emission reduction targets.展开更多
Electrocatalytic conversion of carbon dioxide to high value-added chemicals is a promising method for solving the energy crisis and global warming.Electrochemical active metal-containing conjugated polymers have been ...Electrocatalytic conversion of carbon dioxide to high value-added chemicals is a promising method for solving the energy crisis and global warming.Electrochemical active metal-containing conjugated polymers have been widely studied for heterogeneous carbon dioxide reduction.In the present contribution,we designed and synthesized a stable cobalt phthalocyanine-based conjugated polymer,named CoPPc-TFPPy-CP,and also explored its electro-catalytic application in carbon dioxide reduction to liquid products in an aqueous solution.In the catalyst,cobalt phthalocyanine acts as building blocks connected with 1,3,6,8-tetrakis(4-formyl phenyl)pyrenes via imine-linkages,leading to mesoporous formation polymers with the pore size centered at 4.1nm.And the central co-balt atoms shifted to a higher oxidation state after condensation.With these chemical and structural natures,the catalyst displayed a remarkable electrocatalytic CO_(2) reduction performance with an ethanol Faradaic efficiency of 43.25%at-1.0V vs RHE.While at the same time,the electrochemical reduction process catalyzed by cobalt phthalocyanine produced only carbon monoxide and hydrogen.To the best of our knowledge,CoPPc-TFPPy-CP is the first example among organic polymers and metal-organic frameworks that produces ethanol from CO_(2) with a remarkable selectivity.展开更多
The ethanol electro-reforming process was studied over PtRu/C catalysts synthesized by the modified polyol method with different compositions.In particular,this work reports the influence of anodic Pt:Ru ratio(5:1,2:1...The ethanol electro-reforming process was studied over PtRu/C catalysts synthesized by the modified polyol method with different compositions.In particular,this work reports the influence of anodic Pt:Ru ratio(5:1,2:1 and 1:2)on the organic product distribution(acetaldehyde,acetic acid and ethyl acetate)and pure hydrogen generation at different current densities operation levels.Physicochemical characterization of the catalysts was made by X-ray diffraction(XRD),temperature-programmed reduction(TPR)and N_(2) adsorption-desorption measurements.XRD patterns showed that Ru is introduced into the Pt structure,forming an alloy between both metals.Also,the degree of alloy was higher by increasing the Ru amounts.From TPR profiles Pt was found to be properly reduced while Ru was both in metallic state and forming RuO2.The electrochemical behaviour of each catalyst towards ethanol electroreforming process was investigated through electrochemical techniques in a half cell and a single proton exchange membrane(PEM)cell systems.An intermediate Pt:Ru ratio was found to result in high current density and electrochemical surface area(ECSA)values along with lower amounts of adsorbed species.Also,Ru addition seems to diminish the degree of degradation of the catalyst.Based on characterization and in agreement with essays carried out in a PEM cell at mild conditions(80℃ and 1 atm),PtRu/C 2:1 anode provided the best electrocatalytic results in terms of current density(740 mA cm^(-2)),hydrogen production and selectivity toward acetic acid(up to 15%apart from acetaldehyde and ethyl acetate)while requiring the lowest energy consumption.展开更多
Pramipexole belongs to a class of nonergot dopamine agonist recently approved for the treatment of early and advanced Parkinson's disease.A validated specific stability indicating reversed-phase liquid chromatographi...Pramipexole belongs to a class of nonergot dopamine agonist recently approved for the treatment of early and advanced Parkinson's disease.A validated specific stability indicating reversed-phase liquid chromatographic method has been developed for the quantitative determination of pramipexole in bulk as well as in pharmaceutical dosage forms in the presence of degradation products.Forced degradation studies were performed by exposition of drug to hydrolytic(acidic and basic),oxidative and photolytic stress conditions,as defined under ICH guideline Q1A(R2).Significant degradation was observed under hydrolytic,oxidative and photolytic conditions and the degradation products formed were identified by LC-MS.展开更多
On the bases of the field survey and a large number of testing data, we process the qualitative and quantitative assessment of the mine environment in the mid south of Shandong Province using the following grade Ⅰ fa...On the bases of the field survey and a large number of testing data, we process the qualitative and quantitative assessment of the mine environment in the mid south of Shandong Province using the following grade Ⅰ factors:the surface subsidence in mining area, the three wastes of mine industries, the pollution sources, the surface water pollution, the underground water pollution and the air pollution. By means of emitting factor judgment and water quality indexes, we locate pollution sources, main pollutants, pollution type and pollution grade in the study area. Using the MAPGIS, we draw a zonality map of the mine environment. This paper attempts to offer a concrete example, including valuable assessment method, data and conclusion, for the assessment of mine environment from the integrated assessment of mineral resources and mine environment. This research is oriented towards the sustainable development and the ecological environment optimization.展开更多
Internet financial wealth management product(IFWMP)has recently been one of the most popularity.There is limited quantitative research on IFWMP which can helps customers to choose the products based on the significanc...Internet financial wealth management product(IFWMP)has recently been one of the most popularity.There is limited quantitative research on IFWMP which can helps customers to choose the products based on the significance of each factor.In the paper,a multi-criteria decision-making model of IFWMP was developed,namely analytic hierarchy process(AHP)which is used to make decisions to the unstructured problems through quantifying weights of each criterion.This paper investigated ten influential factors relevant to the purchase of IFWMP and analyzed the frequency of collected responds to show the significance of factors.Based on the quantified weights,the result of the research indicated that compatibility,product liquidity,perceived ease of use and perceived usefulness affect the investors purchasing behaviors most that every investors should pay great attention to.展开更多
Internet financial wealth management product(IFWMP)has recently been one of the most gained popularity.There are limited quantitative research on IFWMP which can help customers to choose products based on the signific...Internet financial wealth management product(IFWMP)has recently been one of the most gained popularity.There are limited quantitative research on IFWMP which can help customers to choose products based on the significance of each factor.In this paper,a multi-criteria decision-making model for IFWMP was developed,namely the analytic hierarchy process(AHP)which is commonly used to make decisions for unstructured problems through quantifying weights of each criterion.This paper investigated ten influential factors relevant to the purchase of IFWMP and analyzed the frequency of collected response to show the significance of the factors.Based on the quantified weights,the results of the research indicated that compatibility,product liquidity,perceived ease of use,and perceived usefulness affected investors purchasing behaviors and that every investor should pay great attention to.展开更多
Coupling electrochemical CO_(2)reduction(CO_(2)R)with a renewable energy source to create high‐value fuels and chemicals is a promising strategy in moving toward a sustainable global energy economy.CO_(2)R liquid pro...Coupling electrochemical CO_(2)reduction(CO_(2)R)with a renewable energy source to create high‐value fuels and chemicals is a promising strategy in moving toward a sustainable global energy economy.CO_(2)R liquid products,such as formate,acetate,ethanol,and propanol,offer high volumetric energy density and are more easily stored and transported than their gaseous coun-terparts.However,a significant amount(~30%)of liquid products from electrochemical CO_(2)R in a flow cell reactor cross the ion exchange membrane,leading to the substantial loss of system‐level Faradaic efficiency.This severe crossover of the liquid product has—until now—received limited attention.Here,we review promising methods to suppress liquid product crossover,including the use of bipolar membranes,solid‐state electrolytes,and cation‐exchange membranes‐based acidic CO_(2)R systems.We then outline the re-maining challenges and future prospects for the production of concentrated liquid products from CO_(2).展开更多
In this paper,we developed and validated a simple,sensitive,and selective high-performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS) method to identify and measure the following prohibited substance...In this paper,we developed and validated a simple,sensitive,and selective high-performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS) method to identify and measure the following prohibited substances that may be found in cosmetic products:minoxidil,hydrocortisone, spironolactone,estrone,canrenone,triamcinolone acetonide and progesterone.Chromatographic separation was performed on a Waters Symmetry C18(100 mm×2.1 mm,3.5μm particle size) with a gradient elution system composed of 0.2%(v/v) formic acid aqueous solution and methanol containing 0.2%(v/v) formic acid at a flow rate of 0.3 mL/min.The substances were detected using a triple quadrupole mass spectrometer in the multiple reaction monitoring mode with an electrospray ionization source.All of the calibration curves showed good linearity(r 〉 0.999) within the tested concentration ranges.The limit of detection was 〈25 pg.The relative standard deviations for intraday precision for each of the prohibited substances were 〈3.5%at two concentration levels(2μg/g,10μg/g). The relative recovery rate for each of the prohibited substances ranged from 91.8%to 111%at three concentration levels(0.1μg/g,2μg/g,10μg/g),including the limit of quantification.In conclusion,we have developed and validated a method that can identify seven prohibited substances in cosmetic products.展开更多
A comparative study was conducted using two designs of a roxatidine acetate (ROX)-selective electrode; a conventional liquid inner contact called electrode A and a graphite-coated solid contact called electrode 13. ...A comparative study was conducted using two designs of a roxatidine acetate (ROX)-selective electrode; a conventional liquid inner contact called electrode A and a graphite-coated solid contact called electrode 13. The fabrication of electrodes was based on roxatidine-tetraphenylborate (ROX-TPB) as an ion-association complex in a PVC matrix using different plasticizers. Electrode A has a linear dynamic range of 2.2 ×10^-5 mol/L to 1.0 ×10^-2 mol/L, with a Nernstian slope of 54.7 mV/decade and a detection limit of 1.4 ×10^-6 mol/L. Electrode B shows linearity over the concentration range of 1.0×10^-6 mol/L to 1.0×10^-2 tool/L, with a Nernstian slope of 51.2 mV/decade and a limit of detection of 1.1×10^7 mol/L which is remarkably improved as a result of diminishing ion fluxes in this solid contact, ion-selective electrode. The proposed sensors display useful analytical characteristics for the determination of ROX in bulk powder and its pharmaceutical formulation. The present electrodes show clear discrimination of ROX from several inorganic, organic ions, sugars, some common drug excipients and the degradation product (3-[3-(1-piperidinyl methyl) phenoxy] propyl amine) of ROX. Furthermore, the proposed electrodes were utilized for the determination of ROX in human plasma, where electrode B covers drug Cmax which indicated its applicability to pharmacokinetic, bioavailability and bioequivalent studies. The results obtained by the proposed electrodes were statistically analyzed and compared with those obtained by a reported HPLC method. No significant difference for either accuracy or precision was observed.展开更多
基金Supported by the Fundamental Research Funds for the Central Universities(JUSRP11205)
文摘Extraction of theanine from waste liquid of tea polyphenol production was studied in aqueous surfactanttwo-phase system (ASTP) with cationic surfactant (CTAB) and anionic surfactant (SDS). Results indicate that the region of ASTP is narrow and there is only a two-phase region of cationic surfactant. The increase in concentrations of NaBr and Na2SO4 are beneficial to the formation of ASTP. Theanine concentration in the bottom phase increases with increasing concentration of theanine, whereas the Partition coefficient and extraction rate only change a littlewhen the concentration of theanine is above 0.2 g.L-'. With the increase of SDS concentration, the phase ratio and the partition coefficient decrease, while the extraction efficiency of theanine increases and the concentration of theanine changes a little in the range from 2.4/7.5 to 2.8/7.2 for SDS/CTAB ratio. The temperature has a notable ef- fect on the concentration of theanine in the bottom phase, partition coefficient and extraction rate of theanine. The increase of waste liquid decreases the phase ratio, increases the concentration and extraction rate of theanine in the bottom ohase, since the orotein and the saccharide enter the bottom nhase with theanine.
文摘The quantities of gas released into the environment during the extraction and processing of crude oil,by flaring,constitute a vast source of mineral wealth which can be used to produce other useful products.The processes studied in this paper,as alternatives to the above problem,are the ones used in Shell Pearl Qatar project and Oryx GTL project.Both projects produce liquid fuels,mainly naphtha and diesel,in addition to more special fuel such as kerosene.This paper is a feasibility study of a project that makes use of the flare gas from the State of Texas,U.S.A.,as a feedstock to a process similar to either Shell Pearl Qatar project,or Oryx GTL project.The objective of this study is to determine the price range for crude oil over which an investment to similar projects can be profitable.An MS Excel Model was developed in order to perform calculations having as a variable the crude oil price and taking into account all the process and project’s financial data.The results of this model showed that a project similar to Shell Pearl Qatar remains profitable in crude oil price above$57.76/barrel,while a project similar to Oryx GTL remains viable for crude oil price over$31.4/bbl.In the price range$55-$60/barrel,the payout of the corresponding to Shell Pearl Qatar project will be in about 15.2 years and 3.3 years for a project similar to Oryx GTL.Finally,using the financial principles of this study we can apply them to any process in order to determine under what conditions will remain viable.
文摘The effect of cooling liquid used for heat exchangers on the Cu alloy corrosion products has been examined using potential-time measurements under applied current condition (anodizing), potentiodynamic polarization, X-ray diffraction (XRD) and infrared spectroscopy (IR) The corrosion products formed on the Cu alloy surface during anodizing, are Cu2O, Cu2(OH)3Cl, and Cu2S. NaCl is detected in the corrosion products. The film formation depends on the applied current and the shift of potential to nobler direction indicates its formation progress.
文摘The Karachi Port of Pakistan is a deep natural sea port with a history of 150 years. The Port has an 11 km long approach channel decaracted with buoys for proriding safe navigation of 75,000 DWT tankers,modern container vessels,bulk Karachi Port is the premier port of Pakistan and handles over 85 percent of the whole dry gen-
基金National Natural Science Foundation of China(grant numbers 71961137012,71874055)National Science Centre,Poland(2018/30/Q/HS4/00764)research support by the Energy,Climate and Environment Program of International Institute for Applied System Analysis(IIASA)within the Young Scientists Summer Program(YSSP).
文摘Efforts to provide alternative resources and technologies for producing liquid fuel have recently been intensified.Different levels of dependence on oil imports and carbon prices have a significant impact on the composition of the cost-minimizing portfolio of technologies.Considering such factors,how should China plan its future liquid fuel industry?The model for supporting the technology portfolio and capacity configuration that minimizes the total system cost until 2045 is described in this study.The results obtained for different carbon prices and levels of dependence on oil import indicate that the oil-to-liquid fuel(OTL)will remain dominant in China's liquid fuel industry over the next three decades.If the carbon price is low,the coal-to-liquid fuel(CTL)process is competitive.For a high carbon price,the biomass-to-liquid fuel(BTL)technology expands more rapidly.The results also reveal that developing the BTL and CTL can effectively reduce the oil-import dependency;moreover,a high carbon price can lead to the CTL being replaced with the low-carbon technology(e.g.,BTL).Improvement in energy raw material conversion and application of CO_(2) removal technologies are also effective methods to control carbon emissions for achieving the carbon emission goals and ultimately emission reduction targets.
基金the financial support from the National Natural Science Foundation of China(22005099)。
文摘Electrocatalytic conversion of carbon dioxide to high value-added chemicals is a promising method for solving the energy crisis and global warming.Electrochemical active metal-containing conjugated polymers have been widely studied for heterogeneous carbon dioxide reduction.In the present contribution,we designed and synthesized a stable cobalt phthalocyanine-based conjugated polymer,named CoPPc-TFPPy-CP,and also explored its electro-catalytic application in carbon dioxide reduction to liquid products in an aqueous solution.In the catalyst,cobalt phthalocyanine acts as building blocks connected with 1,3,6,8-tetrakis(4-formyl phenyl)pyrenes via imine-linkages,leading to mesoporous formation polymers with the pore size centered at 4.1nm.And the central co-balt atoms shifted to a higher oxidation state after condensation.With these chemical and structural natures,the catalyst displayed a remarkable electrocatalytic CO_(2) reduction performance with an ethanol Faradaic efficiency of 43.25%at-1.0V vs RHE.While at the same time,the electrochemical reduction process catalyzed by cobalt phthalocyanine produced only carbon monoxide and hydrogen.To the best of our knowledge,CoPPc-TFPPy-CP is the first example among organic polymers and metal-organic frameworks that produces ethanol from CO_(2) with a remarkable selectivity.
基金the Spanish Ministry of Economy and Competitiveness(projects CTQ2016-75491-R)for the financial support。
文摘The ethanol electro-reforming process was studied over PtRu/C catalysts synthesized by the modified polyol method with different compositions.In particular,this work reports the influence of anodic Pt:Ru ratio(5:1,2:1 and 1:2)on the organic product distribution(acetaldehyde,acetic acid and ethyl acetate)and pure hydrogen generation at different current densities operation levels.Physicochemical characterization of the catalysts was made by X-ray diffraction(XRD),temperature-programmed reduction(TPR)and N_(2) adsorption-desorption measurements.XRD patterns showed that Ru is introduced into the Pt structure,forming an alloy between both metals.Also,the degree of alloy was higher by increasing the Ru amounts.From TPR profiles Pt was found to be properly reduced while Ru was both in metallic state and forming RuO2.The electrochemical behaviour of each catalyst towards ethanol electroreforming process was investigated through electrochemical techniques in a half cell and a single proton exchange membrane(PEM)cell systems.An intermediate Pt:Ru ratio was found to result in high current density and electrochemical surface area(ECSA)values along with lower amounts of adsorbed species.Also,Ru addition seems to diminish the degree of degradation of the catalyst.Based on characterization and in agreement with essays carried out in a PEM cell at mild conditions(80℃ and 1 atm),PtRu/C 2:1 anode provided the best electrocatalytic results in terms of current density(740 mA cm^(-2)),hydrogen production and selectivity toward acetic acid(up to 15%apart from acetaldehyde and ethyl acetate)while requiring the lowest energy consumption.
文摘Pramipexole belongs to a class of nonergot dopamine agonist recently approved for the treatment of early and advanced Parkinson's disease.A validated specific stability indicating reversed-phase liquid chromatographic method has been developed for the quantitative determination of pramipexole in bulk as well as in pharmaceutical dosage forms in the presence of degradation products.Forced degradation studies were performed by exposition of drug to hydrolytic(acidic and basic),oxidative and photolytic stress conditions,as defined under ICH guideline Q1A(R2).Significant degradation was observed under hydrolytic,oxidative and photolytic conditions and the degradation products formed were identified by LC-MS.
文摘On the bases of the field survey and a large number of testing data, we process the qualitative and quantitative assessment of the mine environment in the mid south of Shandong Province using the following grade Ⅰ factors:the surface subsidence in mining area, the three wastes of mine industries, the pollution sources, the surface water pollution, the underground water pollution and the air pollution. By means of emitting factor judgment and water quality indexes, we locate pollution sources, main pollutants, pollution type and pollution grade in the study area. Using the MAPGIS, we draw a zonality map of the mine environment. This paper attempts to offer a concrete example, including valuable assessment method, data and conclusion, for the assessment of mine environment from the integrated assessment of mineral resources and mine environment. This research is oriented towards the sustainable development and the ecological environment optimization.
文摘Internet financial wealth management product(IFWMP)has recently been one of the most popularity.There is limited quantitative research on IFWMP which can helps customers to choose the products based on the significance of each factor.In the paper,a multi-criteria decision-making model of IFWMP was developed,namely analytic hierarchy process(AHP)which is used to make decisions to the unstructured problems through quantifying weights of each criterion.This paper investigated ten influential factors relevant to the purchase of IFWMP and analyzed the frequency of collected responds to show the significance of factors.Based on the quantified weights,the result of the research indicated that compatibility,product liquidity,perceived ease of use and perceived usefulness affect the investors purchasing behaviors most that every investors should pay great attention to.
文摘Internet financial wealth management product(IFWMP)has recently been one of the most gained popularity.There are limited quantitative research on IFWMP which can help customers to choose products based on the significance of each factor.In this paper,a multi-criteria decision-making model for IFWMP was developed,namely the analytic hierarchy process(AHP)which is commonly used to make decisions for unstructured problems through quantifying weights of each criterion.This paper investigated ten influential factors relevant to the purchase of IFWMP and analyzed the frequency of collected response to show the significance of the factors.Based on the quantified weights,the results of the research indicated that compatibility,product liquidity,perceived ease of use,and perceived usefulness affected investors purchasing behaviors and that every investor should pay great attention to.
文摘Coupling electrochemical CO_(2)reduction(CO_(2)R)with a renewable energy source to create high‐value fuels and chemicals is a promising strategy in moving toward a sustainable global energy economy.CO_(2)R liquid products,such as formate,acetate,ethanol,and propanol,offer high volumetric energy density and are more easily stored and transported than their gaseous coun-terparts.However,a significant amount(~30%)of liquid products from electrochemical CO_(2)R in a flow cell reactor cross the ion exchange membrane,leading to the substantial loss of system‐level Faradaic efficiency.This severe crossover of the liquid product has—until now—received limited attention.Here,we review promising methods to suppress liquid product crossover,including the use of bipolar membranes,solid‐state electrolytes,and cation‐exchange membranes‐based acidic CO_(2)R systems.We then outline the re-maining challenges and future prospects for the production of concentrated liquid products from CO_(2).
基金the State Food and Drug Administration of the People's Republic of China for financially supporting this work
文摘In this paper,we developed and validated a simple,sensitive,and selective high-performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS) method to identify and measure the following prohibited substances that may be found in cosmetic products:minoxidil,hydrocortisone, spironolactone,estrone,canrenone,triamcinolone acetonide and progesterone.Chromatographic separation was performed on a Waters Symmetry C18(100 mm×2.1 mm,3.5μm particle size) with a gradient elution system composed of 0.2%(v/v) formic acid aqueous solution and methanol containing 0.2%(v/v) formic acid at a flow rate of 0.3 mL/min.The substances were detected using a triple quadrupole mass spectrometer in the multiple reaction monitoring mode with an electrospray ionization source.All of the calibration curves showed good linearity(r 〉 0.999) within the tested concentration ranges.The limit of detection was 〈25 pg.The relative standard deviations for intraday precision for each of the prohibited substances were 〈3.5%at two concentration levels(2μg/g,10μg/g). The relative recovery rate for each of the prohibited substances ranged from 91.8%to 111%at three concentration levels(0.1μg/g,2μg/g,10μg/g),including the limit of quantification.In conclusion,we have developed and validated a method that can identify seven prohibited substances in cosmetic products.
文摘A comparative study was conducted using two designs of a roxatidine acetate (ROX)-selective electrode; a conventional liquid inner contact called electrode A and a graphite-coated solid contact called electrode 13. The fabrication of electrodes was based on roxatidine-tetraphenylborate (ROX-TPB) as an ion-association complex in a PVC matrix using different plasticizers. Electrode A has a linear dynamic range of 2.2 ×10^-5 mol/L to 1.0 ×10^-2 mol/L, with a Nernstian slope of 54.7 mV/decade and a detection limit of 1.4 ×10^-6 mol/L. Electrode B shows linearity over the concentration range of 1.0×10^-6 mol/L to 1.0×10^-2 tool/L, with a Nernstian slope of 51.2 mV/decade and a limit of detection of 1.1×10^7 mol/L which is remarkably improved as a result of diminishing ion fluxes in this solid contact, ion-selective electrode. The proposed sensors display useful analytical characteristics for the determination of ROX in bulk powder and its pharmaceutical formulation. The present electrodes show clear discrimination of ROX from several inorganic, organic ions, sugars, some common drug excipients and the degradation product (3-[3-(1-piperidinyl methyl) phenoxy] propyl amine) of ROX. Furthermore, the proposed electrodes were utilized for the determination of ROX in human plasma, where electrode B covers drug Cmax which indicated its applicability to pharmacokinetic, bioavailability and bioequivalent studies. The results obtained by the proposed electrodes were statistically analyzed and compared with those obtained by a reported HPLC method. No significant difference for either accuracy or precision was observed.