The separation of carbon dioxide(CO_(2))is of great importance for environment protection and gas resource purification.The ionic liquids(ILs)-based gas separation membrane provides a new chance for efficient CO_(2)se...The separation of carbon dioxide(CO_(2))is of great importance for environment protection and gas resource purification.The ionic liquids(ILs)-based gas separation membrane provides a new chance for efficient CO_(2)separation,while high permeability and selectivity of membranes is a great challenge.In this study,the influence of two protic ILs with different anion([TMGH][Im]and[TMGH][PhO])on the CO_(2)separation performance of the prepared ILs/Pebax blended membranes were systematically investigated at different temperature.The results showed the CO_(2)permeability exhibits the rising trend for ILs/Pebax blended membranes with the increment of IL content.Especially,the[TMGH][Im]with low viscosity and high CO_(2)absorption capacity leads to the blended membranes showing better CO_(2)permeability and ideal CO_(2)selectivity than that of membranes with[TMGH][PhO]at high IL content.Besides,with operating temperature increasing,the gas permeability of 20%(mass)[TMGH][Im]/Pebax blended membrane increases due to the decreasing viscosity of IL and the rising chain mobility of polymer.Inversely,the gas selectivity shows decreasing trend because CO_(2)absorption capacity obviously decreased at higher temperature.展开更多
Nowadays,the use of social media is everywhere in college campuses.You can often see students who stare down at the mobile phone screen and brush the dynamic circle of friends,even community meetings,group discussions...Nowadays,the use of social media is everywhere in college campuses.You can often see students who stare down at the mobile phone screen and brush the dynamic circle of friends,even community meetings,group discussions are beginning to be replaced by WeChat Group.The rapid development of social media allows marketers to see more possibilities for marketing.College students group is a group that marketers can not ignore,this kind of target consumers also have their own characteristics.Only by understanding the characteristics and behavior of consumers can we better discover and spread demand.This paper will analyze the influence of the development of social media on the consumption behavior of college students,and put forward some suggestions on how to use social media to carry out marketing.展开更多
Ceramics are considered intrinsically brittle at macro scale due to the lack of slip mechanism and pre-existing defects,which greatly limits their potential applications in emerging fields including wearable electroni...Ceramics are considered intrinsically brittle at macro scale due to the lack of slip mechanism and pre-existing defects,which greatly limits their potential applications in emerging fields including wearable electronic devices and flexible display.In this contribution,we developed BiFeO_(3)/SiO_(2) dual-networks with exceptional flexibility through a coupled electronetting/electrospun method.The hybrid nanostructured networks endow the material with high tensile strength(2.7 MPa),excellent flexibility(80%recoverable deformation),and robust fatigue resistance performance(maintain flexibility after a 1000-cyclic compress test).After in-situ compounded with dielectric polymer via a layer-by-layer solution casting method,the resultant three-dimensional(3D)composite film exhibits a twice higher dielectric constant(εr)than polyether imide(PEI)film.More importantly,the breakdown strength of the 3D composite film is almost the same as that of the PEI film,resulting in an enhanced energy density of~6.0 J/cm^(3) and a high efficiency of 80%at 4.58 MV/cm.The unique structure,combined with the excellent balance between mechanical and dielectric properties in flexible structures,is of critical significance to the design of flexible functional ceramics and broadening their applications in wearable electric devices.展开更多
Dielectric materials play a crucial and unique role in modern advanced electrical and electronics engineering applications,lending their applicability to their desirable characteristics such as ultrafast charge/discha...Dielectric materials play a crucial and unique role in modern advanced electrical and electronics engineering applications,lending their applicability to their desirable characteristics such as ultrafast charge/discharge rate(~μs),long cycling life(>10^(6)without observable capacity deterioration).展开更多
Subcortical vascular mild cognitive impairment(svMCI)is a common prodromal stage of vascular dementia.Although mounting evidence has suggested abnormalities in several single brain network metrics,few studies have exp...Subcortical vascular mild cognitive impairment(svMCI)is a common prodromal stage of vascular dementia.Although mounting evidence has suggested abnormalities in several single brain network metrics,few studies have explored the consistency between functional and structural connectivity networks in svMCI.Here,we constructed such networks using resting-state f MRI for functional connectivity and diffusion tensor imaging for structural connectivity in 30 patients with svMCI and 30 normal controls.The functional networks were then parcellated into topological modules,corresponding to several well-defined functional domains.The coupling between the functional and structural networks was finally estimated and compared at the multiscale network level(whole brain and modular level).We found no significant intergroup differences in the functional–structural coupling within the whole brain;however,there was significantly increased functional–structural coupling within the dorsal attention module and decreased functional–structural coupling within the ventral attention module in the svMCI group.In addition,the svMCI patients demonstrated decreased intramodular connectivity strength in the visual,somatomotor,and dorsal attention modules as well as decreased intermodular connectivity strength between several modules in the functional network,mainly linking the visual,somatomotor,dorsal attention,ventral attention,and frontoparietal control modules.There was no significant correlation between the altered module-level functional–structural coupling and cognitive performance in patients with svMCI.These findings demonstrate for the first time that svMCI is reflected in a selective aberrant topological organization in multiscale brain networks and may improve our understanding of the pathophysiological mechanisms underlying svMCI.展开更多
Flexible ferroelectric memories,endowing with high data storage density,provide a chance for the nextgeneration wearable electronics.Here,flexible inorganic Mn-doped BiFeO_(3) thin films were directly integrated on fl...Flexible ferroelectric memories,endowing with high data storage density,provide a chance for the nextgeneration wearable electronics.Here,flexible inorganic Mn-doped BiFeO_(3) thin films were directly integrated on fluorophlogopite mica(F-Mica)substrates by an easy and low-cost all solution chemical solution deposition(AS-CSD)route.The integration of LaNiO_(3) buffer layer can improve the film surface density and uniformity.The flexible characteristic can be achieved by reducing the thickness of F-Mica substrates for the ferroelectric thin films.In contrast to BiFe_(0.93)Mn_(0.07)O_(3)/LaNiO_(3)/Si thin film deposited on rigid substrates(Si),the BiFe_(0.93)Mn_(0.07)O_(3)/LaNiO_(3)/F-mica fabricated on F-Mica show better ferroelectric performances due to the improved crystal growth and less defects.More importantly,the obtained BiFe_(0.93)Mn_(0.07)O_(3)/LaNiO_(3)/F-mica ferroelectric thin films still show large remnant polarization of Pr ~64 μC/cm^(2)(deterioration of ~7.2%),good antifatigue properties up to 1.2×10^(8) cycles and outstanding retention behaviors for 1.6×10^(4) s after continuous bending.This work will provide a feasible route to fabricate flexible inorganic ferroelectric thin films through low-cost solution method and show attractive comprehensive performances in next-generation wearable smart devices.展开更多
Searching for effective hydrogen evolution reaction(HER)electrocatalysts is crucial for water splitting.Transition metal nitrides(TMNs)are very attractive potential candidates since of high electrical conductivity,rob...Searching for effective hydrogen evolution reaction(HER)electrocatalysts is crucial for water splitting.Transition metal nitrides(TMNs)are very attractive potential candidates since of high electrical conductivity,robust stability,element rich and high activity.Antiperovskite metal nitrides provide chemical flexibility since two different types of transition metal elements are contained,allowing partial substitution both for A-and M-sites.Herein,we report a novel antiperovskite metal nitride Ag_(x)Ni_(1-x)NNi_(3)(0≤x≤0.80)thin film used as highly effective HER electrocatalysts.Pure phase antiperovskite nitride can be successfully obtained for Ag_(x)Ni_(1-x)NNi_(3)with x less than 0.80.The Ag_(0.76)Ni_(0.24)NNi_(3) towards HER shows an overpotential of 122 mV at 10 mA cm^(-2)in alkaline media.Furthermore,considering the role of Ag for adsorbing hydroxyl groups,chemical engineering has been carried out for designing metal/antiperovskite nitride Ag/Ag_(x)Ni_(1-x)NNi_(3)composite electrocatalysts.The 0.18 Ag/Ag_(0.80)Ni_(0.20)NNi_(3)electrocatalyst shows a mere 13 and 81 mV of overpotential to reach 1 and 10 mA cm^(-2),respectively,showing high durability in alkaline media.These results will provide a novel type of HER catalysts based on antiperovskite metal nitrides and a strategic design for metal/antiperovskite metal nitride composite electrocatalysts for HER in alkaline media.展开更多
基金supported by the National Key R&D Program of China(2020YFA0710200)the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(21921005)+2 种基金the Major Scientific and Technological Project of Shanxi Province of China(20201102005)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2020047)the Innovation Academy for Green Manufacture,Chinese Academy of Sciences(IAGM2020C15)。
文摘The separation of carbon dioxide(CO_(2))is of great importance for environment protection and gas resource purification.The ionic liquids(ILs)-based gas separation membrane provides a new chance for efficient CO_(2)separation,while high permeability and selectivity of membranes is a great challenge.In this study,the influence of two protic ILs with different anion([TMGH][Im]and[TMGH][PhO])on the CO_(2)separation performance of the prepared ILs/Pebax blended membranes were systematically investigated at different temperature.The results showed the CO_(2)permeability exhibits the rising trend for ILs/Pebax blended membranes with the increment of IL content.Especially,the[TMGH][Im]with low viscosity and high CO_(2)absorption capacity leads to the blended membranes showing better CO_(2)permeability and ideal CO_(2)selectivity than that of membranes with[TMGH][PhO]at high IL content.Besides,with operating temperature increasing,the gas permeability of 20%(mass)[TMGH][Im]/Pebax blended membrane increases due to the decreasing viscosity of IL and the rising chain mobility of polymer.Inversely,the gas selectivity shows decreasing trend because CO_(2)absorption capacity obviously decreased at higher temperature.
文摘Nowadays,the use of social media is everywhere in college campuses.You can often see students who stare down at the mobile phone screen and brush the dynamic circle of friends,even community meetings,group discussions are beginning to be replaced by WeChat Group.The rapid development of social media allows marketers to see more possibilities for marketing.College students group is a group that marketers can not ignore,this kind of target consumers also have their own characteristics.Only by understanding the characteristics and behavior of consumers can we better discover and spread demand.This paper will analyze the influence of the development of social media on the consumption behavior of college students,and put forward some suggestions on how to use social media to carry out marketing.
文摘离子液体(ILs)改性固体催化剂是一种构筑高效电催化界面的方法。为了研究ILs阳离子在催化剂中Pt表面对燃料电池中氧还原反应(ORR)性能的影响,本研究自主合成了两种疏水质子型ILs ([EIM][NTf_(2)],[BIM][NTf_(2)])和两种疏水非质子型ILs([EMIM][NTf_(2)],[BMIM][NTf_(2)]),并对商业化Pt/C进行改性。在本研究采用的咪唑类疏水ILs中,质子型ILs改性催化剂的ORR活性均高于非质子型ILs改性催化剂,其中,由1-丁基咪唑双(三氟甲磺酰)亚胺改性后的催化剂([BIM][NTf_(2)]@Pt/C)活性最高。在酸性半电池中ORR半波电位高达0.913 V (vs.RHE),质量活性提升至商业化Pt/C的1.73倍,比活性提升至商业化Pt/C的3倍,同时达到5000圈循环后半波电位仅下降12 mV,性能仍高于商业化Pt/C。进一步材料表征和电化学测试表明,[BIM][NTf_(2)]@Pt/C电催化活性的增强归因于该ILs可增多Pt表面参与反应活性位点、强化Pt表面质子及质量传递,并可有效抑制Pt纳米颗粒溶解,从而起到了增强ORR活性及稳定性的作用。本研究深化了对ILs@Pt界面协同电催化机理的认识,为设计下一代高效燃料电池催化剂提供了理论依据。
基金supported by the National Key R&D Program of China (No.2021YFB3800601)the National Natural Science Foundation of China (No.52102275)+2 种基金China Postdoctoral Science Foundation (Nos.2021TQ0163 and 2021M701821)the Open Youth Fund project of Foshan (South China)Institute of New Materials (No.2021AYF25011)Shuimu Tsinghua Scholar Program。
文摘Ceramics are considered intrinsically brittle at macro scale due to the lack of slip mechanism and pre-existing defects,which greatly limits their potential applications in emerging fields including wearable electronic devices and flexible display.In this contribution,we developed BiFeO_(3)/SiO_(2) dual-networks with exceptional flexibility through a coupled electronetting/electrospun method.The hybrid nanostructured networks endow the material with high tensile strength(2.7 MPa),excellent flexibility(80%recoverable deformation),and robust fatigue resistance performance(maintain flexibility after a 1000-cyclic compress test).After in-situ compounded with dielectric polymer via a layer-by-layer solution casting method,the resultant three-dimensional(3D)composite film exhibits a twice higher dielectric constant(εr)than polyether imide(PEI)film.More importantly,the breakdown strength of the 3D composite film is almost the same as that of the PEI film,resulting in an enhanced energy density of~6.0 J/cm^(3) and a high efficiency of 80%at 4.58 MV/cm.The unique structure,combined with the excellent balance between mechanical and dielectric properties in flexible structures,is of critical significance to the design of flexible functional ceramics and broadening their applications in wearable electric devices.
文摘Dielectric materials play a crucial and unique role in modern advanced electrical and electronics engineering applications,lending their applicability to their desirable characteristics such as ultrafast charge/discharge rate(~μs),long cycling life(>10^(6)without observable capacity deterioration).
基金supported by the Natural Science Foundation of Tianjin Municipal Science and Technology Commission(18JCQNJC10900)Tianjin Natural Science Foundation(17JCZDJC36300)。
文摘Subcortical vascular mild cognitive impairment(svMCI)is a common prodromal stage of vascular dementia.Although mounting evidence has suggested abnormalities in several single brain network metrics,few studies have explored the consistency between functional and structural connectivity networks in svMCI.Here,we constructed such networks using resting-state f MRI for functional connectivity and diffusion tensor imaging for structural connectivity in 30 patients with svMCI and 30 normal controls.The functional networks were then parcellated into topological modules,corresponding to several well-defined functional domains.The coupling between the functional and structural networks was finally estimated and compared at the multiscale network level(whole brain and modular level).We found no significant intergroup differences in the functional–structural coupling within the whole brain;however,there was significantly increased functional–structural coupling within the dorsal attention module and decreased functional–structural coupling within the ventral attention module in the svMCI group.In addition,the svMCI patients demonstrated decreased intramodular connectivity strength in the visual,somatomotor,and dorsal attention modules as well as decreased intermodular connectivity strength between several modules in the functional network,mainly linking the visual,somatomotor,dorsal attention,ventral attention,and frontoparietal control modules.There was no significant correlation between the altered module-level functional–structural coupling and cognitive performance in patients with svMCI.These findings demonstrate for the first time that svMCI is reflected in a selective aberrant topological organization in multiscale brain networks and may improve our understanding of the pathophysiological mechanisms underlying svMCI.
基金supported by the National Key Basic Research program(Grant No.2014CB931704)the Joint Funds of the National Natural Science Foundation of China and the Chinese Academy of Sciences Large-Scale Scientific Facility(Grant No.U1432137).
文摘Flexible ferroelectric memories,endowing with high data storage density,provide a chance for the nextgeneration wearable electronics.Here,flexible inorganic Mn-doped BiFeO_(3) thin films were directly integrated on fluorophlogopite mica(F-Mica)substrates by an easy and low-cost all solution chemical solution deposition(AS-CSD)route.The integration of LaNiO_(3) buffer layer can improve the film surface density and uniformity.The flexible characteristic can be achieved by reducing the thickness of F-Mica substrates for the ferroelectric thin films.In contrast to BiFe_(0.93)Mn_(0.07)O_(3)/LaNiO_(3)/Si thin film deposited on rigid substrates(Si),the BiFe_(0.93)Mn_(0.07)O_(3)/LaNiO_(3)/F-mica fabricated on F-Mica show better ferroelectric performances due to the improved crystal growth and less defects.More importantly,the obtained BiFe_(0.93)Mn_(0.07)O_(3)/LaNiO_(3)/F-mica ferroelectric thin films still show large remnant polarization of Pr ~64 μC/cm^(2)(deterioration of ~7.2%),good antifatigue properties up to 1.2×10^(8) cycles and outstanding retention behaviors for 1.6×10^(4) s after continuous bending.This work will provide a feasible route to fabricate flexible inorganic ferroelectric thin films through low-cost solution method and show attractive comprehensive performances in next-generation wearable smart devices.
基金financially supported by the National Key R&D Program of China(Nos.2016YFA0401801 and 2014CB931704)the Natural Science Foundation of Anhui Province(No.1608085QE107)+1 种基金the Key Research Program of Frontier Sciences,CAS(No.QYZDB-SSW-SLH015)supported by the Youth Innovation Promotion Association of CAS(No.2014283)。
文摘Searching for effective hydrogen evolution reaction(HER)electrocatalysts is crucial for water splitting.Transition metal nitrides(TMNs)are very attractive potential candidates since of high electrical conductivity,robust stability,element rich and high activity.Antiperovskite metal nitrides provide chemical flexibility since two different types of transition metal elements are contained,allowing partial substitution both for A-and M-sites.Herein,we report a novel antiperovskite metal nitride Ag_(x)Ni_(1-x)NNi_(3)(0≤x≤0.80)thin film used as highly effective HER electrocatalysts.Pure phase antiperovskite nitride can be successfully obtained for Ag_(x)Ni_(1-x)NNi_(3)with x less than 0.80.The Ag_(0.76)Ni_(0.24)NNi_(3) towards HER shows an overpotential of 122 mV at 10 mA cm^(-2)in alkaline media.Furthermore,considering the role of Ag for adsorbing hydroxyl groups,chemical engineering has been carried out for designing metal/antiperovskite nitride Ag/Ag_(x)Ni_(1-x)NNi_(3)composite electrocatalysts.The 0.18 Ag/Ag_(0.80)Ni_(0.20)NNi_(3)electrocatalyst shows a mere 13 and 81 mV of overpotential to reach 1 and 10 mA cm^(-2),respectively,showing high durability in alkaline media.These results will provide a novel type of HER catalysts based on antiperovskite metal nitrides and a strategic design for metal/antiperovskite metal nitride composite electrocatalysts for HER in alkaline media.
