BACKGROUND In recent years,the prevalence of obesity and metabolic syndrome in type 1 diabetes(T1DM)patients has gradually increased.Insulin resistance in T1DM deserves attention.It is necessary to clarify the relatio...BACKGROUND In recent years,the prevalence of obesity and metabolic syndrome in type 1 diabetes(T1DM)patients has gradually increased.Insulin resistance in T1DM deserves attention.It is necessary to clarify the relationship between body composition,metabolic syndrome and insulin resistance in T1DM to guide clinical treatment and intervention.AIM To assess body composition(BC)in T1DM patients and evaluate the relationship between BC,metabolic syndrome(MS),and insulin resistance in these indi-viduals.METHODS A total of 101 subjects with T1DM,aged 10 years or older,and with a disease duration of over 1 year were included.Bioelectrical impedance analysis using the Tsinghua-Tongfang BC Analyzer BCA-1B was employed to measure various BC parameters.Clinical and laboratory data were collected,and insulin resistance was calculated using the estimated glucose disposal rate(eGDR).RESULTS MS was diagnosed in 16/101 patients(15.84%),overweight in 16/101 patients(15.84%),obesity in 4/101(3.96%),hypertension in 34/101(33.66%%)and dyslip-idemia in 16/101 patients(15.84%).Visceral fat index(VFI)and trunk fat mass were significantly and negatively correlated with eGDR(both P<0.001).Female patients exhibited higher body fat percentage and visceral fat ratio compared to male patients.Binary logistic regression analysis revealed that significant factors for MS included eGDR[P=0.017,odds ratio(OR)=0.109],VFI(P=0.030,OR=3.529),and a family history of diabetes(P=0.004,OR=0.228).Significant factors for hypertension included eGDR(P<0.001,OR=0.488)and skeletal muscle mass(P=0.003,OR=1.111).Significant factors for dyslipidemia included trunk fat mass(P=0.033,OR=1.202)and eGDR(P=0.037,OR=0.708).CONCLUSION Visceral fat was found to be a superior predictor of MS compared to conventional measures such as body mass index and waist-to-hip ratio in Chinese individuals with T1DM.BC analysis,specifically identifying visceral fat(trunk fat),may play an important role in identifying the increased risk of MS in non-obese patients with T1DM.展开更多
Objective To study the effect of allitridum on the transient outward potassium current （Ito） of ventricular myocytes in heart failure （HF）. Methods The dual enzymatic method was used to separate single ventricular...Objective To study the effect of allitridum on the transient outward potassium current （Ito） of ventricular myocytes in heart failure （HF）. Methods The dual enzymatic method was used to separate single ventricular myocytes from Sprague Dawley rats. Patch-clamping was used to record Ito and analyze the effect of allitridum on the current. Results The Ito current had a significant decrease in the HF group, compared with the control group. The density of Ito in the HF group was increased after treatment of allitridum （30 μmol/L）. The peak current densities of Ito were enhanced in the HF group from 6.01 ±0.30 pA/pF to 8.41 ±0.54 pA/pF （P 〈 0.01） at ＋50 mV after treatment with allitridum （30 μmol/L）. We also determined the effect of allitridum on the gating mechanism of the Ito in the HF group. Conclusions We found that allitridum increased the Ito by accelerating the activation of channels and shortened the time constants of inactivation, and allitridum decreased the remodeling of Ito in ventricular myocytes of rats with HF.展开更多
Generally,most materials expand when heated and contract when cooled,whereas negative thermal expansion(NTE)materials are very rare.As a typical NTE material,PbTiO_(3) and related compounds have drawn particular inter...Generally,most materials expand when heated and contract when cooled,whereas negative thermal expansion(NTE)materials are very rare.As a typical NTE material,PbTiO_(3) and related compounds have drawn particular interest in recent years.The discovery of an enhanced NTE system in PbTiO_(3) is beneficial to deepen our understanding of its mechanism and regulate its properties.At present,the method of discriminating an enhanced NTE material based on PbTiO_(3) is not universal.Here,we propose a semi-empirical method through evaluating the average lattice distortion in related systems to estimate the relative coefficient of thermal expansion conveniently.The rationality of the method was verified by the analysis of the 0.6PbTiO_(3)-0.4Bi(Ga_(x)Fe_(1-x))O_(3) system.So far,all PbTiO_(3)-based compounds with enhanced NTE conform well to this method.This method provides the possibility to find more enhanced NTE PbTiO_(3)-based materials.展开更多
As a crucial environmental reform system to realize“carbon peaking”and“carbon neutrality”,the pilot policy of low-carbon cities(LCCs)puts pressure and challenges on high-carbon emitting enterprises(HCEEs)while pro...As a crucial environmental reform system to realize“carbon peaking”and“carbon neutrality”,the pilot policy of low-carbon cities(LCCs)puts pressure and challenges on high-carbon emitting enterprises(HCEEs)while providing opportunities for these firms to take the path of independent transformation.Employing the data of Chinese listed enterprises from 2006 to 2016 and adopting a difference-in-differences(DID)model,we evaluated the impact of LCC construction on the upgrading of HCEEs and its mechanisms.The results indicate that LCC construction enhances the upgrading of HCEEs in the pilot cities.The conclusions remain stable after a series of robustness tests.The mechanism analysis reveals that LCC construction triggers the upgrading of HCEEs by promoting resource allocation efficiency,R&D investment,and green technology innovation.The heterogeneity results indicate that this positive effect is more pronounced for HCEEs in regions with more stringent environmental law enforcement.This study also observes that the upgrading impact is more promi‐nent for state-owned enterprises,enterprises with higher bargaining power,and enterprises whose managers have a long-term vision.The above results provide directions for upgrading HCEEs and replicable evidence for cities in developing economies to fulfill the win-win target of environmental protection and economic transfor‐mation.展开更多
BackgroundPocket hematoma is one of the major complications associated with cardiovascular implantable electronic devices （CIEDs） implantation. The aim of this study is to evaluate the impact of body mass index （BM...BackgroundPocket hematoma is one of the major complications associated with cardiovascular implantable electronic devices （CIEDs） implantation. The aim of this study is to evaluate the impact of body mass index （BMI） on the occurrence of pocket hematoma after CIEDs implantation.MethodsThe study is a retrospective review of 972 patients receiving CIEDs implantation between 2008 and 2012 in a tertiary hospital.ResultsTwenty two patients （2.2%） developed severe pocket hematoma requiring re-intervention. The hematoma rate （4.6%,n = 15） of patients with a BMI of 〈 23 kg/m2 was significantly higher compared with that of patients with a BMI of≥23 kg/m2 （1.1%, n = 7,P〈 0.001）. In multivariate regression analysis, a BMI 〈 23.0 kg/m2 may be associated with the development of severe pocket hema-toma. An increase of 1.0 kg/m2 in BMI was associated with lower incidence of hematoma formation （OR： 0.84; 95% CI： 0.74-0.95;P = 0.006）.ConclusionBMI 〈 23 kg/m2 was associated with a higher incidence of pocket hematoma, requiring re-intervention. The data sup-port that great care must be taken when patients were with a lower BMI received CIEDs implantation.展开更多
Alloys with low thermal expansion could overcome thermal stress issues under temperature-fluctuated conditions and possess important application prospects,while they are restricted to finite chemical components and te...Alloys with low thermal expansion could overcome thermal stress issues under temperature-fluctuated conditions and possess important application prospects,while they are restricted to finite chemical components and temperature windows.In this study,we report a novel class of near-zero thermal expansion(near ZTE)alloys,ErFe_(10)V_(2−x)Mo_(x),over a wide temperature range(120–440 K).Neutron diffraction and magnetic measurements demonstrated that the ErFe_(10)V_(2−x)Mo_(x)compounds exhibited complex ferrimagnetic(FIM)structures below Curie temperature(TC).The near-ZTE behaviors were closely related to the itinerant Fe 3d moments in the collinear FIM states,as well as the geometric[−Fe−Fe−]linkages.Further,X-ray absorption near-edge structure(XANES)spectra revealed that the nonmagnetic substitution changed the electronic valence states of Fe atoms,which,in turn,changed Fe 3d moments and TC,hence,regulating the thermal expansion behaviors.Our work provides an insight into chemical modifications of thermal expansion in magnetic intermetallic compounds.展开更多
The development of low-cost and high-performance ZnO Schottky photodetectors (PDs) has drawn intensive attention,but still a challenge due to their poor conductivity and low light utilization efficiency.Here,we introd...The development of low-cost and high-performance ZnO Schottky photodetectors (PDs) has drawn intensive attention,but still a challenge due to their poor conductivity and low light utilization efficiency.Here,we introduce Ti_(3)C_(2)T_(X) into ZnO films to fabricate Schottky UV PDs via facile spin-coated method.The fabricated ZnO/Ti_(3)C_(2)T_(X)/ZnO compound film shows outstanding performance on photocurrent,responsivity,noise equivalent power (NEP),normalized detection rate (D~*),and linear dynamic region (LDR),compared with the original Zn O device.The photocurrent is significantly increased by 466%,and the responsivity is improved by one order of magnitude.In addition,it exhibits relatively low NEP (5.99×10^(-11)W),strong D~*(2.53×10~9 Jones),and high LDR (28 dB).The superior performance is ascribed to the enhanced conductivity and light absorption of ZnO film after introduction of Ti_(3)C_(2)T_(X) modification layer,leading to simultaneously faster electron transfer,lower the radiation recombination of electron and holes on the ZnO/Ti_(3)C_(2)T_(X)/ZnO compound film.This work provides a facile way to develop low-cost and highperformance ZnO Schottky PDs.展开更多
Thermal expansion is an essential issue in the field of materials science and engineering.Investigation of anomalous thermal expansion is beneficial to controlling it and developing related functions.Here,we report di...Thermal expansion is an essential issue in the field of materials science and engineering.Investigation of anomalous thermal expansion is beneficial to controlling it and developing related functions.Here,we report disitinctly anisotropic thermal expansion of CrB_(2)via temperature dependence of neutron diffraction,in which positive thermal expansion is observed within basal plane whereas negative thermal expansion emerges along the c direction.Intriguingly,zero thermal expansion of unit cell volume is determined from 5 to 130 K with the coefficient of thermal expansion ofāv=0.4(1)×10^(-6)K^(-1).Magnetization measurement shows there is an antiferromagnetic-paramagnetic transition near 90 K,which may correlate to the thermal expansion anomaly.DFT calculations identify no chemical binding of Cr-Cr pair,implying such antiferromagnetic ordering originates from the double exchange interaction of Cr-B-Cr.展开更多
The study reviews all medusa genera and species belonging to the families Bougainvilliidae, Eucodoniidae, Proboscidactylidae, Corymorphidae and Sugiuridae from the northern South China Sea. A new genus Xu, Guo & W...The study reviews all medusa genera and species belonging to the families Bougainvilliidae, Eucodoniidae, Proboscidactylidae, Corymorphidae and Sugiuridae from the northern South China Sea. A new genus Xu, Guo & Wang, gen. nov. is erected under the family Sugiuridae, based on the monotype, Monocanna ovale(Mayer, 1900) comb. nov. from Gastroblasta. Four new species, Nubiella terminaliknoba Xu, Guo & Wang sp. nov., Paranubiella shenzhenensis Xu, Huang & Wang, sp. nov., Eucodonium crassonemalis Xu, Guo & Lin, sp. nov. and Proboscidactyla trifurcata Xu, Huang & Guo, sp. nov., are described and illustrated here. The species Euphysora knides Huang, 1999 stat. rev. is revised to be a valid species. The keys to known genera of families Corymorphidae, Sugiuridae and species of genera Paranubiella, Eucodonium, Proboscidactyla are provided. All type specimens are deposited in the College of Ocean and Earth Sciences, Xiamen University.展开更多
Zero thermal expansion(ZTE)alloys have unique aspects in the application of the engineering of precise dimensional control.However,the harsh conditions to realize ZTE,i.e.,appropriate coupling among spin,lattice,and c...Zero thermal expansion(ZTE)alloys have unique aspects in the application of the engineering of precise dimensional control.However,the harsh conditions to realize ZTE,i.e.,appropriate coupling among spin,lattice,and charge upon heating,have limited the ZTE alloys by very few numbers of species.In this work,we report a route to achieving twodimensional(2D)ZTE behavior by regulating crystallographic texture and magneto-volume effects(MVEs)in volumetric positive thermal expansion alloys.This is illustrated in a series of Mn_(x)Fe_(5-x)Si_(3)compounds by those earth-abundant elements.As a result,a 2D ZTE performance with a coefficient of thermal expansion α_(1)=0.45×10^(-7)K^(-1) over a broad temperature window of 10–310 K was observed in MnFe4Si3.The experimental results by synchrotron X-ray diffraction,neutron diffraction,microscopy,and magnetization measurements reveal that such a ZTE behavior is strongly coupled with fiber crystallographic texture and magnetic moment at the crystallographic 6g site that dominates MVEs in the a-b plane.The competition between ferromagnetic Fe_(4d)–Fe_(6g)(J_(FM))and antiferromagnetic Mn_(4d)–Mn_(6g)(J_(AFM))interactions makes the Mn_(1.5)Fe_(3.5)Si_(3) and Mn_(2)Fe_(3)Si_(3)compounds show mixed magnetism and negative thermal expansion(NTE).The integral approach presented here can be used to extend the scope of ZTE/NTE species in other magnetic or ferroelectric materials.展开更多
基金Supported by the“SDF-sweet doctor cultivation”Project of Sinocare Diabetes Foundation,No.2022SD11 and No.2021SD09.
文摘BACKGROUND In recent years,the prevalence of obesity and metabolic syndrome in type 1 diabetes(T1DM)patients has gradually increased.Insulin resistance in T1DM deserves attention.It is necessary to clarify the relationship between body composition,metabolic syndrome and insulin resistance in T1DM to guide clinical treatment and intervention.AIM To assess body composition(BC)in T1DM patients and evaluate the relationship between BC,metabolic syndrome(MS),and insulin resistance in these indi-viduals.METHODS A total of 101 subjects with T1DM,aged 10 years or older,and with a disease duration of over 1 year were included.Bioelectrical impedance analysis using the Tsinghua-Tongfang BC Analyzer BCA-1B was employed to measure various BC parameters.Clinical and laboratory data were collected,and insulin resistance was calculated using the estimated glucose disposal rate(eGDR).RESULTS MS was diagnosed in 16/101 patients(15.84%),overweight in 16/101 patients(15.84%),obesity in 4/101(3.96%),hypertension in 34/101(33.66%%)and dyslip-idemia in 16/101 patients(15.84%).Visceral fat index(VFI)and trunk fat mass were significantly and negatively correlated with eGDR(both P<0.001).Female patients exhibited higher body fat percentage and visceral fat ratio compared to male patients.Binary logistic regression analysis revealed that significant factors for MS included eGDR[P=0.017,odds ratio(OR)=0.109],VFI(P=0.030,OR=3.529),and a family history of diabetes(P=0.004,OR=0.228).Significant factors for hypertension included eGDR(P<0.001,OR=0.488)and skeletal muscle mass(P=0.003,OR=1.111).Significant factors for dyslipidemia included trunk fat mass(P=0.033,OR=1.202)and eGDR(P=0.037,OR=0.708).CONCLUSION Visceral fat was found to be a superior predictor of MS compared to conventional measures such as body mass index and waist-to-hip ratio in Chinese individuals with T1DM.BC analysis,specifically identifying visceral fat(trunk fat),may play an important role in identifying the increased risk of MS in non-obese patients with T1DM.
基金Acknowledgments This work was supported by the National Natural Science Foundation of China （No： 81170177, 81030002 and 8147054）. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. There is no competing interest to declare.
文摘Objective To study the effect of allitridum on the transient outward potassium current （Ito） of ventricular myocytes in heart failure （HF）. Methods The dual enzymatic method was used to separate single ventricular myocytes from Sprague Dawley rats. Patch-clamping was used to record Ito and analyze the effect of allitridum on the current. Results The Ito current had a significant decrease in the HF group, compared with the control group. The density of Ito in the HF group was increased after treatment of allitridum （30 μmol/L）. The peak current densities of Ito were enhanced in the HF group from 6.01 ±0.30 pA/pF to 8.41 ±0.54 pA/pF （P 〈 0.01） at ＋50 mV after treatment with allitridum （30 μmol/L）. We also determined the effect of allitridum on the gating mechanism of the Ito in the HF group. Conclusions We found that allitridum increased the Ito by accelerating the activation of channels and shortened the time constants of inactivation, and allitridum decreased the remodeling of Ito in ventricular myocytes of rats with HF.
基金financially supported by the National Key R&D Program of China(No.2020YFA0406202)the National Natural Science Foundation of China(Nos.22090042 and 21731001)。
文摘Generally,most materials expand when heated and contract when cooled,whereas negative thermal expansion(NTE)materials are very rare.As a typical NTE material,PbTiO_(3) and related compounds have drawn particular interest in recent years.The discovery of an enhanced NTE system in PbTiO_(3) is beneficial to deepen our understanding of its mechanism and regulate its properties.At present,the method of discriminating an enhanced NTE material based on PbTiO_(3) is not universal.Here,we propose a semi-empirical method through evaluating the average lattice distortion in related systems to estimate the relative coefficient of thermal expansion conveniently.The rationality of the method was verified by the analysis of the 0.6PbTiO_(3)-0.4Bi(Ga_(x)Fe_(1-x))O_(3) system.So far,all PbTiO_(3)-based compounds with enhanced NTE conform well to this method.This method provides the possibility to find more enhanced NTE PbTiO_(3)-based materials.
基金This paper was supported by the Fundamental Research Funds for the Central Universities[Grant number:JBK2202018].
文摘As a crucial environmental reform system to realize“carbon peaking”and“carbon neutrality”,the pilot policy of low-carbon cities(LCCs)puts pressure and challenges on high-carbon emitting enterprises(HCEEs)while providing opportunities for these firms to take the path of independent transformation.Employing the data of Chinese listed enterprises from 2006 to 2016 and adopting a difference-in-differences(DID)model,we evaluated the impact of LCC construction on the upgrading of HCEEs and its mechanisms.The results indicate that LCC construction enhances the upgrading of HCEEs in the pilot cities.The conclusions remain stable after a series of robustness tests.The mechanism analysis reveals that LCC construction triggers the upgrading of HCEEs by promoting resource allocation efficiency,R&D investment,and green technology innovation.The heterogeneity results indicate that this positive effect is more pronounced for HCEEs in regions with more stringent environmental law enforcement.This study also observes that the upgrading impact is more promi‐nent for state-owned enterprises,enterprises with higher bargaining power,and enterprises whose managers have a long-term vision.The above results provide directions for upgrading HCEEs and replicable evidence for cities in developing economies to fulfill the win-win target of environmental protection and economic transfor‐mation.
文摘BackgroundPocket hematoma is one of the major complications associated with cardiovascular implantable electronic devices （CIEDs） implantation. The aim of this study is to evaluate the impact of body mass index （BMI） on the occurrence of pocket hematoma after CIEDs implantation.MethodsThe study is a retrospective review of 972 patients receiving CIEDs implantation between 2008 and 2012 in a tertiary hospital.ResultsTwenty two patients （2.2%） developed severe pocket hematoma requiring re-intervention. The hematoma rate （4.6%,n = 15） of patients with a BMI of 〈 23 kg/m2 was significantly higher compared with that of patients with a BMI of≥23 kg/m2 （1.1%, n = 7,P〈 0.001）. In multivariate regression analysis, a BMI 〈 23.0 kg/m2 may be associated with the development of severe pocket hema-toma. An increase of 1.0 kg/m2 in BMI was associated with lower incidence of hematoma formation （OR： 0.84; 95% CI： 0.74-0.95;P = 0.006）.ConclusionBMI 〈 23 kg/m2 was associated with a higher incidence of pocket hematoma, requiring re-intervention. The data sup-port that great care must be taken when patients were with a lower BMI received CIEDs implantation.
基金supported by the National Natural Science Foundation of China(21701008,21231001,21590793,and 21731001)National Postdoctoral Program for Innovative Talents(BX201700027)the Fundamental Research Funds for the Central Universities,China(FRF-IDRY-19-018).
文摘Alloys with low thermal expansion could overcome thermal stress issues under temperature-fluctuated conditions and possess important application prospects,while they are restricted to finite chemical components and temperature windows.In this study,we report a novel class of near-zero thermal expansion(near ZTE)alloys,ErFe_(10)V_(2−x)Mo_(x),over a wide temperature range(120–440 K).Neutron diffraction and magnetic measurements demonstrated that the ErFe_(10)V_(2−x)Mo_(x)compounds exhibited complex ferrimagnetic(FIM)structures below Curie temperature(TC).The near-ZTE behaviors were closely related to the itinerant Fe 3d moments in the collinear FIM states,as well as the geometric[−Fe−Fe−]linkages.Further,X-ray absorption near-edge structure(XANES)spectra revealed that the nonmagnetic substitution changed the electronic valence states of Fe atoms,which,in turn,changed Fe 3d moments and TC,hence,regulating the thermal expansion behaviors.Our work provides an insight into chemical modifications of thermal expansion in magnetic intermetallic compounds.
基金support from Zhejiang Provincial Natural Science Foundation (No. LY19F050007)the National Natural Science Foundation of China (No. 11604298)Zhoushan Science and Technology Project (Nos. 2019C21029, 2019C21017)。
文摘The development of low-cost and high-performance ZnO Schottky photodetectors (PDs) has drawn intensive attention,but still a challenge due to their poor conductivity and low light utilization efficiency.Here,we introduce Ti_(3)C_(2)T_(X) into ZnO films to fabricate Schottky UV PDs via facile spin-coated method.The fabricated ZnO/Ti_(3)C_(2)T_(X)/ZnO compound film shows outstanding performance on photocurrent,responsivity,noise equivalent power (NEP),normalized detection rate (D~*),and linear dynamic region (LDR),compared with the original Zn O device.The photocurrent is significantly increased by 466%,and the responsivity is improved by one order of magnitude.In addition,it exhibits relatively low NEP (5.99×10^(-11)W),strong D~*(2.53×10~9 Jones),and high LDR (28 dB).The superior performance is ascribed to the enhanced conductivity and light absorption of ZnO film after introduction of Ti_(3)C_(2)T_(X) modification layer,leading to simultaneously faster electron transfer,lower the radiation recombination of electron and holes on the ZnO/Ti_(3)C_(2)T_(X)/ZnO compound film.This work provides a facile way to develop low-cost and highperformance ZnO Schottky PDs.
基金supported by National Key R&D Program of China(2020YFA0406202)National Natural Science Foundation of China(22090042,21731001,22275015 and 21971009)Neutron diffraction experiments were carried out on WOMBAT in Australian Nuclear Science and Technology Organization(ANSTO).
文摘Thermal expansion is an essential issue in the field of materials science and engineering.Investigation of anomalous thermal expansion is beneficial to controlling it and developing related functions.Here,we report disitinctly anisotropic thermal expansion of CrB_(2)via temperature dependence of neutron diffraction,in which positive thermal expansion is observed within basal plane whereas negative thermal expansion emerges along the c direction.Intriguingly,zero thermal expansion of unit cell volume is determined from 5 to 130 K with the coefficient of thermal expansion ofāv=0.4(1)×10^(-6)K^(-1).Magnetization measurement shows there is an antiferromagnetic-paramagnetic transition near 90 K,which may correlate to the thermal expansion anomaly.DFT calculations identify no chemical binding of Cr-Cr pair,implying such antiferromagnetic ordering originates from the double exchange interaction of Cr-B-Cr.
基金supported by the Special Fund for Agro-scientific Research in the Public Interest(201403008)Foundation for Distinguished Young Teachers in Higher Education of Guangdong,China(YQ2014002)+2 种基金the National Natural Science Foundation of China(41876180)Global Climate Change and Ocean Atmosphere Interaction Research:the Marine Biological Sample Museum Upgrade and Expansion(GASI-01-02-04)Biological Classification System Research
文摘The study reviews all medusa genera and species belonging to the families Bougainvilliidae, Eucodoniidae, Proboscidactylidae, Corymorphidae and Sugiuridae from the northern South China Sea. A new genus Xu, Guo & Wang, gen. nov. is erected under the family Sugiuridae, based on the monotype, Monocanna ovale(Mayer, 1900) comb. nov. from Gastroblasta. Four new species, Nubiella terminaliknoba Xu, Guo & Wang sp. nov., Paranubiella shenzhenensis Xu, Huang & Wang, sp. nov., Eucodonium crassonemalis Xu, Guo & Lin, sp. nov. and Proboscidactyla trifurcata Xu, Huang & Guo, sp. nov., are described and illustrated here. The species Euphysora knides Huang, 1999 stat. rev. is revised to be a valid species. The keys to known genera of families Corymorphidae, Sugiuridae and species of genera Paranubiella, Eucodonium, Proboscidactyla are provided. All type specimens are deposited in the College of Ocean and Earth Sciences, Xiamen University.
基金supported by the National Key R&D Program of China(2020YFA0406202)the National Natural Science Foundation of China(22090042,21971009 and 21731001)+1 种基金the Fundamental Research Funds for the Central Universities,China(FRF-IDRY-19-018 and FRF-BR-19-003B)Neutron texture analysis was carried out at the Spallation Neutron Source(SNS)(Proposal No.2020B26069)。
文摘Zero thermal expansion(ZTE)alloys have unique aspects in the application of the engineering of precise dimensional control.However,the harsh conditions to realize ZTE,i.e.,appropriate coupling among spin,lattice,and charge upon heating,have limited the ZTE alloys by very few numbers of species.In this work,we report a route to achieving twodimensional(2D)ZTE behavior by regulating crystallographic texture and magneto-volume effects(MVEs)in volumetric positive thermal expansion alloys.This is illustrated in a series of Mn_(x)Fe_(5-x)Si_(3)compounds by those earth-abundant elements.As a result,a 2D ZTE performance with a coefficient of thermal expansion α_(1)=0.45×10^(-7)K^(-1) over a broad temperature window of 10–310 K was observed in MnFe4Si3.The experimental results by synchrotron X-ray diffraction,neutron diffraction,microscopy,and magnetization measurements reveal that such a ZTE behavior is strongly coupled with fiber crystallographic texture and magnetic moment at the crystallographic 6g site that dominates MVEs in the a-b plane.The competition between ferromagnetic Fe_(4d)–Fe_(6g)(J_(FM))and antiferromagnetic Mn_(4d)–Mn_(6g)(J_(AFM))interactions makes the Mn_(1.5)Fe_(3.5)Si_(3) and Mn_(2)Fe_(3)Si_(3)compounds show mixed magnetism and negative thermal expansion(NTE).The integral approach presented here can be used to extend the scope of ZTE/NTE species in other magnetic or ferroelectric materials.
