The bending responses of functionally graded （FG） nanobeams with simply supported edges are investigated based on Timoshenko beam theory in this article. The Gurtin-Murdoch surface elasticity theory is adopted to an...The bending responses of functionally graded （FG） nanobeams with simply supported edges are investigated based on Timoshenko beam theory in this article. The Gurtin-Murdoch surface elasticity theory is adopted to analyze the influences of surface stress on bending response of FG nanobeam. The material properties are assumed to vary along the thickness of FG nanobeam in power law. The bending governing equations are derived by using the minimum total potential energy principle and explicit formulas are derived for rotation angle and deflection of nanobeams with surface effects. Illustrative examples are implemented to give the bending deformation of FG nanobeam. The influences of the aspect ratio, gradient index, and surface stress on dimensionless deflection are discussed in detail.展开更多
Super-heavy oil is a significant unconventional energy source,and more than 30 years of research have shown that steam-assisted gravity drainage(SAGD)technology is suitable for thick super-heavy oil reservoirs.Recentl...Super-heavy oil is a significant unconventional energy source,and more than 30 years of research have shown that steam-assisted gravity drainage(SAGD)technology is suitable for thick super-heavy oil reservoirs.Recently,more and more thin-layer super-heavy oil reservoirs have been discovered in China,while their deep buried depth and serous heterogeneity make the existing SAGD technology difficult to apply,so it is urgent to improve the existing SAGD technology for the thin-layer super-heavy oil.To this end,this paper focuses on the enlightenment of field application in SAGD technology.Firstly,based on typical SAGD field projects,the development history of SAGD technology in the world was reviewed,and the influence of reservoir physical properties on the application of SAGD technology in thin-layer superheavy oil reservoirs was analyzed.Secondly,the well pattern,wellbore structure,pre-heating,artificial lift,and monitor technique of SAGD were detailed described,and their adjustment direction was expounded for the development of thin-layer super-heavy oil reservoirs.Lastly,the gas-and solventassistant SAGD were comprehensively evaluated,and their application potential in thin-layer superheavy oil reservoirs was studied.The research results can provide theoretical guidance for the application of SAGD technology in thin-layer super-heavy oil reservoirs.展开更多
Objective:This article systematically analyses the effects of adverse drug events/adverse drug reactions(ADEs/ADRs)of oral Indigo Naturalis(Qingdai)preparations in order to provide references for its rational clinical...Objective:This article systematically analyses the effects of adverse drug events/adverse drug reactions(ADEs/ADRs)of oral Indigo Naturalis(Qingdai)preparations in order to provide references for its rational clinical application.Methods:All clinical studies reporting ADE/ADR related to the oral administration of Qingdai preparations were searched through electronic databases,including PubMed,the Cochrane Library,Embase,China National Knowledge Infrastructure(CNKI),China Biology Medicine disc(CBM),VIP Information Chinese Journal Service Platform(VIP),and Wanfang database,from inception to September 27,2020.Information were extracted from these literatures,including primary disease,type of adverse reactions,dose,treatment,outcomes and so on.Incidence of ADE/ADR was estimated,as well as distribution of primary diseases and victim organs and systems were analyzed.Results:A total of 682 articles were included,with 651 clinical population studies and 31 case reports.Among them,604 detailed ADR/AE involving 33459 patients using oral Qingdai preparations,and a total of 5061 cases were found to present adverse events,including 2827 cases of digestive system(abdominal pain,diarrhea,etc.),469 cases of blood system damage(thrombocytopenia,leukopenia,anemia,etc.),313 cases of liver damage(abnormal liver function,liver toxicity,elevated liver enzymes,etc.),327 cases of nervous system reactions(headache,dizziness,poor sleep,etc.)and 1186 cases of other systems and organs.Severe adverse events(SAEs)mainly were liver damage,and could be relived after symptomatic treatment.Conclusion:From the systematic information retrieval and analysis,it is found that oral Qingdai preparations application may clinically cause ADEs/ADRs in terms of gastrointestinal tract and liver damage.Therefore,when using oral Qingdai preparations,liver and stomach protection should be done.At the same time,pay close attention to various biochemical indicators and the patient's drug response during the treatment process,and,if necessary,deal with it in time so as not to deteriorate the condition.Moreover,active surveillance system should be conducted to monitor ADE/ADR,so as to establish a clearer causal relationship between the drug and the adverse event.展开更多
The intricate correlation between charge degrees of freedom and physical properties is a fascinating area of research in solid state chemistry and condensed matter physics.Herein,we report on the pressureinduced succe...The intricate correlation between charge degrees of freedom and physical properties is a fascinating area of research in solid state chemistry and condensed matter physics.Herein,we report on the pressureinduced successive charge transfer and accompanied resistive evolution in honeycomb layered ruthenate AgRuO_(3).Structural revisiting and spectroscopic analyses affirm the ilmenite type R-3 structure with mixed valence cations as Ag^(+1/+2)Ru^(+4/+5)O_(3) at ambient pressure.In-situ pressure-and temperature-dependent resistance variation reveals a successive insulatormetal-insulator transition upon pressing,accompanied by unprecedented charge transfer between Ag and Ru under applied pressure,and a further structural phase transition in the insulator region at higher pressure.These phenomena are also corroborated by in-situ pressure-dependent Raman spectra,synchrotron X-ray diffraction,bond valence sums,and electronic structure calculations,emphasizing the dominated rare Ag2+,and near zero thermal expansion in the ab-plane in the metallic zone mostly due to the Jahn-Teller effect of d9-Ag2+.The multiple electronic instabilities in AgRuO_(3) may offer new possibilities toward novel and unconventionally physical and chemical behaviors in strongly correlated honeycomb lattices.展开更多
This paper explores the impact of spatial externalities in shaping China's economic geography by establishing a theoretical framework that contains regional productivity,trade barriers and local amenities to captu...This paper explores the impact of spatial externalities in shaping China's economic geography by establishing a theoretical framework that contains regional productivity,trade barriers and local amenities to capture spatial externalities between different regions over time.Combining provincial data on bilateral trade flows with observed information about economic geography during the period 1998-2013,we estimate the distribution and marginal contribution of each explanatory.factor.Empirical results suggest that regional labor density and wage are positively related to exogenous productivity and amenities,and negatively related to trade barriers.Meanwhile,variation in the marginal contribution of exogenous productivity and amenities and trade barriers reflects the regional temporal-spatial features in China's recent marketization process.Therefore,the Chinese government should place more emphasis on absorbing advanced technologies and reducing inter-regional market barriers to promote balanced regional development and improve the eficiency of China s spatial resource allocation.展开更多
Epigenetics refers to how chromatin-associated factors and reversible chromatin modifications maintain DNA-based programs by regulating the chromatin structure(Strahl and Allis,2000).In recent years,genome sequencing ...Epigenetics refers to how chromatin-associated factors and reversible chromatin modifications maintain DNA-based programs by regulating the chromatin structure(Strahl and Allis,2000).In recent years,genome sequencing studies of cancer have shown that genes encoding epigenetic factors are commonly mutated in cancer(Garraway and Lander,2013).Dys regulated,or mutant.展开更多
Biochar produced from pyrolysis of biomass has been developed as a platform carbonaceous material that can be used in various applications.The specific surface area(SSA)and functionalities such as N-containing functio...Biochar produced from pyrolysis of biomass has been developed as a platform carbonaceous material that can be used in various applications.The specific surface area(SSA)and functionalities such as N-containing functional groups of biochar are the most significant properties determining the application performance of biochar as a carbon material in various areas,such as removal of pollutants,adsorption of CO_(2)and H2,catalysis,and energy storage.Producing biochar with preferable SSA and N functional groups is among the frontiers to engineer biochar materials.This study attempted to build machine learning models to predict and optimize specific surface area of biochar(SSA-char),N content of biochar(N-char),and yield of biochar(Yield-char)individually or simultaneously,by using elemental,proximate,and biochemical compositions of biomass and pyrolysis conditions as input variables.The predictions of Yield-char,N-char,and SSA-char were compared by using random forest(RF)and gradient boosting regression(GBR)models.GBR outperformed RF for most predictions.When input parameters included elemental and proximate compositions as well as pyrolysis conditions,the test R^(2) values for the single-target and multi-target GBR models were 0.90-0.95 except for the two-target prediction of Yield-char and SSA-char which had a test R^(2) of 0.84 and the three-target prediction model which had a test R^(2) of 0.81.As indicated by the Pearson correlation coefficient between variables and the feature importance of these GBR models,the top influencing factors toward predicting three targets were specified as follows:pyrolysis temperature,residence time,and fixed carbon for Yield-char;N and ash for N-char;ash and pyrolysis temperature for SSA-char.The effects of these parameters on three targets were different,but the trade-offs of these three were balanced during multi-target ML prediction and optimization.The optimum solutions were then experimentally verified,which opens a new way for designing smart biochar with target properties and oriented application potential.展开更多
This study investigates 1.5 generation1 Asian immigrant children’s(n=264)early literacy achievement patterns,treating them as a heterogeneous group.Specifically,the within-group variances in reading achievement from ...This study investigates 1.5 generation1 Asian immigrant children’s(n=264)early literacy achievement patterns,treating them as a heterogeneous group.Specifically,the within-group variances in reading achievement from kindergarten to third grade are examined,drawing on four waves of data from the ECLS-K class of 1998-1999.Our analysis shows that ethnicity plays a role in shaping the children’s initial reading readiness and later growth,but the effects of languages spoken at home are not significant.Our analysis also demonstrates a persistent achievement gap between low-and high-socioeconomic status(SES)Asian groups.However,gender difference in terms of children’s reading development is not found to be significant.There is also no interaction between SES and the other factors such as gender,ethnicity and language backgrounds.展开更多
基金supported by the National Natural Science Foundation of China(11302055)Heilongjiang Post-doctoral Scientific Research Start-up Funding(LBH-Q14046)
文摘The bending responses of functionally graded （FG） nanobeams with simply supported edges are investigated based on Timoshenko beam theory in this article. The Gurtin-Murdoch surface elasticity theory is adopted to analyze the influences of surface stress on bending response of FG nanobeam. The material properties are assumed to vary along the thickness of FG nanobeam in power law. The bending governing equations are derived by using the minimum total potential energy principle and explicit formulas are derived for rotation angle and deflection of nanobeams with surface effects. Illustrative examples are implemented to give the bending deformation of FG nanobeam. The influences of the aspect ratio, gradient index, and surface stress on dimensionless deflection are discussed in detail.
基金financially supported by the Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)(Grant Nos.CUGGC09 and CUG200637)Opening Fund of Key Laboratory of Unconventional Oil&Gas Development(China University of Petroleum(East China)),Ministry of Education(Grant No.19CX05005A-201)the Sinopec Science and Technology Department(Grant Nos.P2006 and 33550000-21-ZC0611-0006)。
文摘Super-heavy oil is a significant unconventional energy source,and more than 30 years of research have shown that steam-assisted gravity drainage(SAGD)technology is suitable for thick super-heavy oil reservoirs.Recently,more and more thin-layer super-heavy oil reservoirs have been discovered in China,while their deep buried depth and serous heterogeneity make the existing SAGD technology difficult to apply,so it is urgent to improve the existing SAGD technology for the thin-layer super-heavy oil.To this end,this paper focuses on the enlightenment of field application in SAGD technology.Firstly,based on typical SAGD field projects,the development history of SAGD technology in the world was reviewed,and the influence of reservoir physical properties on the application of SAGD technology in thin-layer superheavy oil reservoirs was analyzed.Secondly,the well pattern,wellbore structure,pre-heating,artificial lift,and monitor technique of SAGD were detailed described,and their adjustment direction was expounded for the development of thin-layer super-heavy oil reservoirs.Lastly,the gas-and solventassistant SAGD were comprehensively evaluated,and their application potential in thin-layer superheavy oil reservoirs was studied.The research results can provide theoretical guidance for the application of SAGD technology in thin-layer super-heavy oil reservoirs.
基金This research was financially supported by The National Key R&D Program of China(Grant No.2019YFC1709802).
文摘Objective:This article systematically analyses the effects of adverse drug events/adverse drug reactions(ADEs/ADRs)of oral Indigo Naturalis(Qingdai)preparations in order to provide references for its rational clinical application.Methods:All clinical studies reporting ADE/ADR related to the oral administration of Qingdai preparations were searched through electronic databases,including PubMed,the Cochrane Library,Embase,China National Knowledge Infrastructure(CNKI),China Biology Medicine disc(CBM),VIP Information Chinese Journal Service Platform(VIP),and Wanfang database,from inception to September 27,2020.Information were extracted from these literatures,including primary disease,type of adverse reactions,dose,treatment,outcomes and so on.Incidence of ADE/ADR was estimated,as well as distribution of primary diseases and victim organs and systems were analyzed.Results:A total of 682 articles were included,with 651 clinical population studies and 31 case reports.Among them,604 detailed ADR/AE involving 33459 patients using oral Qingdai preparations,and a total of 5061 cases were found to present adverse events,including 2827 cases of digestive system(abdominal pain,diarrhea,etc.),469 cases of blood system damage(thrombocytopenia,leukopenia,anemia,etc.),313 cases of liver damage(abnormal liver function,liver toxicity,elevated liver enzymes,etc.),327 cases of nervous system reactions(headache,dizziness,poor sleep,etc.)and 1186 cases of other systems and organs.Severe adverse events(SAEs)mainly were liver damage,and could be relived after symptomatic treatment.Conclusion:From the systematic information retrieval and analysis,it is found that oral Qingdai preparations application may clinically cause ADEs/ADRs in terms of gastrointestinal tract and liver damage.Therefore,when using oral Qingdai preparations,liver and stomach protection should be done.At the same time,pay close attention to various biochemical indicators and the patient's drug response during the treatment process,and,if necessary,deal with it in time so as not to deteriorate the condition.Moreover,active surveillance system should be conducted to monitor ADE/ADR,so as to establish a clearer causal relationship between the drug and the adverse event.
基金supported by the National Science Foundation of China(grant nos.NSFC-22090041,21875287,U1932217,11974246,12004252,12025408,11921004,11974432,and 92165204)the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(grant no.2017ZT07C069)NKRDPC-2017YFA0206203,NKRDPC-2018YFA0306001.
文摘The intricate correlation between charge degrees of freedom and physical properties is a fascinating area of research in solid state chemistry and condensed matter physics.Herein,we report on the pressureinduced successive charge transfer and accompanied resistive evolution in honeycomb layered ruthenate AgRuO_(3).Structural revisiting and spectroscopic analyses affirm the ilmenite type R-3 structure with mixed valence cations as Ag^(+1/+2)Ru^(+4/+5)O_(3) at ambient pressure.In-situ pressure-and temperature-dependent resistance variation reveals a successive insulatormetal-insulator transition upon pressing,accompanied by unprecedented charge transfer between Ag and Ru under applied pressure,and a further structural phase transition in the insulator region at higher pressure.These phenomena are also corroborated by in-situ pressure-dependent Raman spectra,synchrotron X-ray diffraction,bond valence sums,and electronic structure calculations,emphasizing the dominated rare Ag2+,and near zero thermal expansion in the ab-plane in the metallic zone mostly due to the Jahn-Teller effect of d9-Ag2+.The multiple electronic instabilities in AgRuO_(3) may offer new possibilities toward novel and unconventionally physical and chemical behaviors in strongly correlated honeycomb lattices.
基金The authors are grateful for support from the National Natural Science Foundation of China(No.71573269 and No.71873120)the China National Social Science Foundation(No.16BJY119)the Priority Academic Program Development of Jiangsu Higher Education Institutions and Zhejiang Province Natural Science Foundation(No.LY 18G030004).
文摘This paper explores the impact of spatial externalities in shaping China's economic geography by establishing a theoretical framework that contains regional productivity,trade barriers and local amenities to capture spatial externalities between different regions over time.Combining provincial data on bilateral trade flows with observed information about economic geography during the period 1998-2013,we estimate the distribution and marginal contribution of each explanatory.factor.Empirical results suggest that regional labor density and wage are positively related to exogenous productivity and amenities,and negatively related to trade barriers.Meanwhile,variation in the marginal contribution of exogenous productivity and amenities and trade barriers reflects the regional temporal-spatial features in China's recent marketization process.Therefore,the Chinese government should place more emphasis on absorbing advanced technologies and reducing inter-regional market barriers to promote balanced regional development and improve the eficiency of China s spatial resource allocation.
基金supported by the National Natural Science Foundation of China(81672771 and 81871867 to C.X.)the Ministry of Science and Technology of the People’s Republic of China(2017YFA0504102 to D.P.)+1 种基金Tianjin Municipal Special Program of Talents Development for Excellent Youth ScholarsThe Chair of this National Key Research and Development Project(2017YFA0504102)is Duanqing Pei,and the corresponding author of this artical,Chenghao Xuan,is one of the members of the project.
文摘Epigenetics refers to how chromatin-associated factors and reversible chromatin modifications maintain DNA-based programs by regulating the chromatin structure(Strahl and Allis,2000).In recent years,genome sequencing studies of cancer have shown that genes encoding epigenetic factors are commonly mutated in cancer(Garraway and Lander,2013).Dys regulated,or mutant.
基金the National Key Research and Development Program of China(2021YFE0104900)the National Natural Science Foundation of China(51906247)+1 种基金Hunan Provincial Natural Science Foundation of China(2022JJ20064)the Science and Technology Innovation Program of Hunan Province(2021RC4005).
文摘Biochar produced from pyrolysis of biomass has been developed as a platform carbonaceous material that can be used in various applications.The specific surface area(SSA)and functionalities such as N-containing functional groups of biochar are the most significant properties determining the application performance of biochar as a carbon material in various areas,such as removal of pollutants,adsorption of CO_(2)and H2,catalysis,and energy storage.Producing biochar with preferable SSA and N functional groups is among the frontiers to engineer biochar materials.This study attempted to build machine learning models to predict and optimize specific surface area of biochar(SSA-char),N content of biochar(N-char),and yield of biochar(Yield-char)individually or simultaneously,by using elemental,proximate,and biochemical compositions of biomass and pyrolysis conditions as input variables.The predictions of Yield-char,N-char,and SSA-char were compared by using random forest(RF)and gradient boosting regression(GBR)models.GBR outperformed RF for most predictions.When input parameters included elemental and proximate compositions as well as pyrolysis conditions,the test R^(2) values for the single-target and multi-target GBR models were 0.90-0.95 except for the two-target prediction of Yield-char and SSA-char which had a test R^(2) of 0.84 and the three-target prediction model which had a test R^(2) of 0.81.As indicated by the Pearson correlation coefficient between variables and the feature importance of these GBR models,the top influencing factors toward predicting three targets were specified as follows:pyrolysis temperature,residence time,and fixed carbon for Yield-char;N and ash for N-char;ash and pyrolysis temperature for SSA-char.The effects of these parameters on three targets were different,but the trade-offs of these three were balanced during multi-target ML prediction and optimization.The optimum solutions were then experimentally verified,which opens a new way for designing smart biochar with target properties and oriented application potential.
文摘This study investigates 1.5 generation1 Asian immigrant children’s(n=264)early literacy achievement patterns,treating them as a heterogeneous group.Specifically,the within-group variances in reading achievement from kindergarten to third grade are examined,drawing on four waves of data from the ECLS-K class of 1998-1999.Our analysis shows that ethnicity plays a role in shaping the children’s initial reading readiness and later growth,but the effects of languages spoken at home are not significant.Our analysis also demonstrates a persistent achievement gap between low-and high-socioeconomic status(SES)Asian groups.However,gender difference in terms of children’s reading development is not found to be significant.There is also no interaction between SES and the other factors such as gender,ethnicity and language backgrounds.
