The world is undergoing profound changes in energy and technology.Countries are vigorously developing new sustainable energy sources and technologies.Renewable energy sources encompass various technologies such as win...The world is undergoing profound changes in energy and technology.Countries are vigorously developing new sustainable energy sources and technologies.Renewable energy sources encompass various technologies such as wind turbines,solar energy,nuclear energy,and bioenergy.Additionally,emerging technology fields include new energy vehicles,robots,and artificial intelligence devices,among others.The renewable energy industries and implementation of new technologies necessitate the development and adoption of new equipment and components.Austempered ductile iron(ADI)is renowned for its unique microstructure and superior properties.By utilizing ADI,lightweight and innovative castings can be designed to not only reduce weight but also save energy and decrease emissions.More importantly,these castings enhance the efficiency and reliability of new energy equipment and emerging technology installations.This paper describes the development,applications,and future prospects of lightweight and innovative ADI castings within sectors such as solar photovoltaic(PV),wind power generation,industry robots,and trucks in China.展开更多
As a zero-carbon fuel,hydrogen can be produced via electrochemical water splitting using clean electric energy by the hydrogen evolution reaction(HER)process.The ultimate goal of HER catalyst is to replace the expensi...As a zero-carbon fuel,hydrogen can be produced via electrochemical water splitting using clean electric energy by the hydrogen evolution reaction(HER)process.The ultimate goal of HER catalyst is to replace the expensive Pt metal benchmark with a cheap one with equivalent activities.In this work,we investigated the possibility of HER process on single-atom catalysts(SACs)doped on two-dimensional(2D)GaPS_(4)materials,which have a large intrinsic band gap that can be regulated by doping and tensile strain.Based on the machine learning regression analysis,we can expand the prediction of HER performance to more catalysts without expensive DFT calculation.The electron affinity and first ionization energy are the two most important descriptors related to the HER behavior.Furthermore,constrain molecular dynamics with solvation models and constant potentials were applied to understand the dynamics barrier of HER process of Pt SAC on GaPS_(4)materials.These findings not only provide important insights into the catalytic properties of single-atom catalysts on GaPS_(4)2D materials,but also provides theoretical guidance paradigm for exploration of new catalysts.展开更多
Technical standards are important documents for the development, application and expansion of any engineering material. In the casting industry, technical standards are the premise for producing high quality castings ...Technical standards are important documents for the development, application and expansion of any engineering material. In the casting industry, technical standards are the premise for producing high quality castings and they provide tools for inspection and acceptance of castings, and aid both the purchaser and the producer. In this paper, the most recent worldwide and Chinese technical standards for SG iron, ADI, CGI and heat resisting iron castings are described. It can be seen that these Chinese national standards have reached the level of world class standards. This will be beneficial for enhancing the Chinese foundry industry, improving Chinese casting quality and aid the supply of good quality castings to China's own industry. It is also good for the international buyer to source castings in China, and for the Chinese casting producer to export castings to other parts of the world. Current development trends for cast irons are also discussed.展开更多
The design of optimal heterogeneous catalysts for N_(2)-to-NH_(3) conversion is often dictated by the scaling relations,which result in a volcano curve that poses a limit on the catalytic performance.Herein,we reveal ...The design of optimal heterogeneous catalysts for N_(2)-to-NH_(3) conversion is often dictated by the scaling relations,which result in a volcano curve that poses a limit on the catalytic performance.Herein,we reveal a bowl active site that can break the scaling relations,through investigating the catalytic mechanisms of N_(2)-to-NH_(3) conversion on the lanthanide intermetallic electride catalyst LaRuSi by first-principles modeling.This bowl active site,composed of four surface La cations and one subsurface Si atom rich in electrons,plays the key role in enabling efficient catalysis.With adaptive electrostatic and orbital interactions,the bowl active site promotes the adsorption and activation of N_(2) that delivers facile cleavage of N-N bond,while destabilizes the adsorptions of ^(*)NH_(x)(x=1,2,3)species,which facilitates the release of the final NH_(3) product.By comparison with other electride catalysts isostructural to LaRuSi,we confirm the breaking of scaling relations between the adsorptions of ^(*)NH_(x) species and that of^(*)N on the bowl active site.Thus,this bowl active site presents a design concept that breaks the scaling relations for highly efficient heterogeneous catalysis of N_(2)-to-NH_(3) conversion.展开更多
Background This preclinical study in sheep sought to demonstrate the initial safety and feasibility of a novel transcatheter mitral valve system(Mi-thos valve)composed of a self-expanding frame and a bovine pericardia...Background This preclinical study in sheep sought to demonstrate the initial safety and feasibility of a novel transcatheter mitral valve system(Mi-thos valve)composed of a self-expanding frame and a bovine pericardial tissue bioprosthesis.Methods The valve was implanted in 26 sheep using a transapical approach for short-and long-term evaluation.The technical feasibility,safety,durability,and valve function were evaluated during and 6 months after the procedure using intracardiac and transthoracic echocardiography,multisliced computed tomography,histological analysis,and electron microscopy.Results The success rate of valve implantation was 100%,and the immediate survival rate after surgery was 84%.Five animals died within 90 min after the development of the prosthetic valve due to an acute left ventricular outflow tract obstruction(n=2)and sudden intraoperative ventricular fibrillation(n=3).Twelve animals died within 1 month due to acute left heart dysfunction.Mild(n=5)and moderate(n=2)paravalvular leakage occurred in seven animals,and two moderate PVL animals died of chronic heart failure within three months.Multimodality imaging studies of the remaining seven animals showed excellent function and alignment of the valves,with no coronary artery obstruction,no left ventricular outflow tract obstruction,no severe transvalvular gradients and no paravalvular leakage.Macroscopic evaluation demonstrated stable,secure positioning of the valve,with full endothelialization of the valve leaflets without injury to the ventricular or atrial walls.Histological and electron microscopic examinations at six months showed no obvious macro-or microcalcification in the leaflets.Conclusions Preclinical studies indicate that transcatheter implantation of the Mi-thos valve is technically safe and feasible.The durability,functionality,and lack of leaflet calcification were all verified in animal experiments.The information from these preclinical studies will be applied to patient selection criteria and the first-in-human studies.展开更多
Cast iron is an old and new,traditional and modern cast material.Liquid iron appeared in China in about 600 B.C.,and cast iron smelting was introduced in Europe between 1200-1450 A.D.However,cast iron technology devel...Cast iron is an old and new,traditional and modern cast material.Liquid iron appeared in China in about 600 B.C.,and cast iron smelting was introduced in Europe between 1200-1450 A.D.However,cast iron technology developed very slowly until the Industrial Revolution.Cast iron,as a traditional metal material,has advantages of low total cost,good castability and machinability。展开更多
While heterogeneous single-atom catalysts(SACs)have achieved great success in the past decade,their application is potentially limited by their simplistic single-atom active centers,which make single-cluster catalysts...While heterogeneous single-atom catalysts(SACs)have achieved great success in the past decade,their application is potentially limited by their simplistic single-atom active centers,which make single-cluster catalysts(SCCs)a natural extension in the domain of heterogeneous catalysis.SCCs with precise numbers of atoms and structural configurations possess SAC merits,yet have greater potential for catalyzing complex reactions and/or bulky reactants.Through systematic quantum-chemical studies and computational screening,we report here the rational design of transition metal three-atom clusters anchored on graphdiyne(GDY)as a novel kind of stable SCC with great promise for efficient and atomically precise heterogenous catalysis.By investigating their structure and catalytic performance for the oxygen reduction reaction,the hydrogen evolution reaction,and the CO_(2)reduction reaction,we have provided theoretical guidelines for their potential applications as heterogeneous catalysts.These GDY-supported three-atom SCCs provide an ideal benchmark scaffold for rational design of atomically precise heterogeneous catalysts for industrially important chemical reactions.展开更多
Background::Acute type A aortic dissection(ATAAD)and acute type A intramural hematoma(ATAIMH)are life-threatening diseases with high mortality.To better understand their clinical features in the Chinese population,we ...Background::Acute type A aortic dissection(ATAAD)and acute type A intramural hematoma(ATAIMH)are life-threatening diseases with high mortality.To better understand their clinical features in the Chinese population,we analyzed the data from the first Registry of Aortic Dissection in China(Sino-RAD)to promote the understanding and management of the diseases.Methods::All patients with ATAAD and ATAIMH enrolled in Sino-RAD from January 1,2012 to December 31,2016 were involved.The data of patients’selection,history,symptoms,management,outcomes,and postoperation complications were analyzed in the study.The continuous variables were compared using the Student’s t test for normal distributions and the Mann-Whitney U test for non-normal distributions.Categorical variables were compared using the Chi-square test or Fisher exact test.Results::A total of 1582 patients with ATAAD and 130 patients with ATAIMH were included.The mean age of all patients was 48.4 years.Patients with ATAAD were significantly younger than patients with ATAIMH(48.9 years vs.55.6 years,P<0.001).For the total cohort,males were dominant,but the male ratio of patients with ATAAD was significantly higher compared to those with ATAIMH(P=0.01).The time range from the onset of symptom to hospitalization was 2.0 days.More patients of ATAIMH had hypertension than that of ATAAD(82.3%vs.67.6%,P<0.05).Chest and back pain were the most common clinical symptoms.Computerized tomography(CT)was the most common initial diagnostic imaging modality.84.7%received surgical treatment and in-hospital mortality was 5.3%.Patients with ATAAD mainly received surgical treatment(89.6%),while most patients with ATAIMH received medical treatment(39.2%)or endovascular repair(35.4%).Conclusions::Our study suggests that doctors should comprehensively use clinical examination and genetic background screening for patients with ATAAD and ATAIMH and further shorten the time range from symptoms onset to intervention,achieving early diagnosis and treatment,thereby reducing the mortality rate of patients with aortic dissection in China.We should standardize the procedures of aortic dissection treatment and improve people’s understanding.Meanwhile,the curing and transferring efficiency should also be improved.展开更多
The magnetic properties and magnetocaloric effect of an antiferromagnetic/ferromagnetic(AFM/FM)BiFeO_(3)/Co bilayer with mixed-spin(5/2,3/2)have been studied based on Monte Carlo simulation.The magnetization,susceptib...The magnetic properties and magnetocaloric effect of an antiferromagnetic/ferromagnetic(AFM/FM)BiFeO_(3)/Co bilayer with mixed-spin(5/2,3/2)have been studied based on Monte Carlo simulation.The magnetization,susceptibility,and critical temperature are investigated under various exchange couplings and an external magnetic field.In particular,the influence of exchange couplings and an external magnetic field on the magnetic entropy change,adiabatic temperature change,and the relative cooling power(RCP)are studied.The simulation results indicated that the decrease of the exchange coupling and the increase of external magnetic fields can cause an increase of magnetic entropy change,adiabatic temperature change,and RCP.In addition,the hysteresis loops of the system are presented for different exchange couplings and temperatures.展开更多
Mesoporous,hollow Zn O microspheres were synthesized via a hydrothermal method,using glycerol and zinc acetate as the starting materials.XRD and FESEM analysis showed that the surface morphology of the spheres with a ...Mesoporous,hollow Zn O microspheres were synthesized via a hydrothermal method,using glycerol and zinc acetate as the starting materials.XRD and FESEM analysis showed that the surface morphology of the spheres with a Wurtzite structure could be reasonably adjusted by varying the weight ratio(Rw) of Zn(CH3COO)2 2H2O:H2O:C3H8O3.The responses of the gas sensor based on the spheres to 100 ppm ethanol and 100 ppm acetone are 18.9 and 10.4,respectively.The response and recovery times of the sensor to ethanol and acetone are 2 s and 3 s,3 s and 5 s,respectively.The hollow spheres show an intense UV emission at 392 nm and a broad blue-green emission at 488 nm.Interestingly,a light trapping phenomenon is revealed by UV emission and scattering measurements on the microspheres,which can be attributed to the mesoporous shell and hollow structure of the microsphere.展开更多
文摘The world is undergoing profound changes in energy and technology.Countries are vigorously developing new sustainable energy sources and technologies.Renewable energy sources encompass various technologies such as wind turbines,solar energy,nuclear energy,and bioenergy.Additionally,emerging technology fields include new energy vehicles,robots,and artificial intelligence devices,among others.The renewable energy industries and implementation of new technologies necessitate the development and adoption of new equipment and components.Austempered ductile iron(ADI)is renowned for its unique microstructure and superior properties.By utilizing ADI,lightweight and innovative castings can be designed to not only reduce weight but also save energy and decrease emissions.More importantly,these castings enhance the efficiency and reliability of new energy equipment and emerging technology installations.This paper describes the development,applications,and future prospects of lightweight and innovative ADI castings within sectors such as solar photovoltaic(PV),wind power generation,industry robots,and trucks in China.
基金supported by the National Natural Science Foundation of China (Grant No.12164009),which is received by Xuefei Liuthe Guizhou Science and Technology Foundation-ZK[2022]General 308,which is received by Xuefei Liu+2 种基金Top scientific and technological talents in Guizhou Province of Qian Jiaoji[2022]No.078,which is received by Xuefei LiuGraduate Research Fund Project of Guizhou Province (YJSKYJJ[2021]088),which is received by Tianyun Liuthe Haihe Laboratory of Sustainable Chemical Transformation for financial support。
文摘As a zero-carbon fuel,hydrogen can be produced via electrochemical water splitting using clean electric energy by the hydrogen evolution reaction(HER)process.The ultimate goal of HER catalyst is to replace the expensive Pt metal benchmark with a cheap one with equivalent activities.In this work,we investigated the possibility of HER process on single-atom catalysts(SACs)doped on two-dimensional(2D)GaPS_(4)materials,which have a large intrinsic band gap that can be regulated by doping and tensile strain.Based on the machine learning regression analysis,we can expand the prediction of HER performance to more catalysts without expensive DFT calculation.The electron affinity and first ionization energy are the two most important descriptors related to the HER behavior.Furthermore,constrain molecular dynamics with solvation models and constant potentials were applied to understand the dynamics barrier of HER process of Pt SAC on GaPS_(4)materials.These findings not only provide important insights into the catalytic properties of single-atom catalysts on GaPS_(4)2D materials,but also provides theoretical guidance paradigm for exploration of new catalysts.
文摘Technical standards are important documents for the development, application and expansion of any engineering material. In the casting industry, technical standards are the premise for producing high quality castings and they provide tools for inspection and acceptance of castings, and aid both the purchaser and the producer. In this paper, the most recent worldwide and Chinese technical standards for SG iron, ADI, CGI and heat resisting iron castings are described. It can be seen that these Chinese national standards have reached the level of world class standards. This will be beneficial for enhancing the Chinese foundry industry, improving Chinese casting quality and aid the supply of good quality castings to China's own industry. It is also good for the international buyer to source castings in China, and for the Chinese casting producer to export castings to other parts of the world. Current development trends for cast irons are also discussed.
文摘The design of optimal heterogeneous catalysts for N_(2)-to-NH_(3) conversion is often dictated by the scaling relations,which result in a volcano curve that poses a limit on the catalytic performance.Herein,we reveal a bowl active site that can break the scaling relations,through investigating the catalytic mechanisms of N_(2)-to-NH_(3) conversion on the lanthanide intermetallic electride catalyst LaRuSi by first-principles modeling.This bowl active site,composed of four surface La cations and one subsurface Si atom rich in electrons,plays the key role in enabling efficient catalysis.With adaptive electrostatic and orbital interactions,the bowl active site promotes the adsorption and activation of N_(2) that delivers facile cleavage of N-N bond,while destabilizes the adsorptions of ^(*)NH_(x)(x=1,2,3)species,which facilitates the release of the final NH_(3) product.By comparison with other electride catalysts isostructural to LaRuSi,we confirm the breaking of scaling relations between the adsorptions of ^(*)NH_(x) species and that of^(*)N on the bowl active site.Thus,this bowl active site presents a design concept that breaks the scaling relations for highly efficient heterogeneous catalysis of N_(2)-to-NH_(3) conversion.
基金This paper was supported by the National Key Research and Development Plan(2016YFC1101000)National Natural Science Foundation of China(81600240 and 81470500)The Distinguished Young Scholar Cultivation Project of Xijing Hospital(XJZT14J03,XJZT15ZL01,and 13QNP129)。
文摘Background This preclinical study in sheep sought to demonstrate the initial safety and feasibility of a novel transcatheter mitral valve system(Mi-thos valve)composed of a self-expanding frame and a bovine pericardial tissue bioprosthesis.Methods The valve was implanted in 26 sheep using a transapical approach for short-and long-term evaluation.The technical feasibility,safety,durability,and valve function were evaluated during and 6 months after the procedure using intracardiac and transthoracic echocardiography,multisliced computed tomography,histological analysis,and electron microscopy.Results The success rate of valve implantation was 100%,and the immediate survival rate after surgery was 84%.Five animals died within 90 min after the development of the prosthetic valve due to an acute left ventricular outflow tract obstruction(n=2)and sudden intraoperative ventricular fibrillation(n=3).Twelve animals died within 1 month due to acute left heart dysfunction.Mild(n=5)and moderate(n=2)paravalvular leakage occurred in seven animals,and two moderate PVL animals died of chronic heart failure within three months.Multimodality imaging studies of the remaining seven animals showed excellent function and alignment of the valves,with no coronary artery obstruction,no left ventricular outflow tract obstruction,no severe transvalvular gradients and no paravalvular leakage.Macroscopic evaluation demonstrated stable,secure positioning of the valve,with full endothelialization of the valve leaflets without injury to the ventricular or atrial walls.Histological and electron microscopic examinations at six months showed no obvious macro-or microcalcification in the leaflets.Conclusions Preclinical studies indicate that transcatheter implantation of the Mi-thos valve is technically safe and feasible.The durability,functionality,and lack of leaflet calcification were all verified in animal experiments.The information from these preclinical studies will be applied to patient selection criteria and the first-in-human studies.
文摘Cast iron is an old and new,traditional and modern cast material.Liquid iron appeared in China in about 600 B.C.,and cast iron smelting was introduced in Europe between 1200-1450 A.D.However,cast iron technology developed very slowly until the Industrial Revolution.Cast iron,as a traditional metal material,has advantages of low total cost,good castability and machinability。
基金This work was financially supported by the National Natural Science Foundation of China(grant no.22033005 to J.L.and grant no.21903047 to H.X.)The support of Guangdong Provincial Key Laboratory of Catalysis(grant no.2020B121201002)is also acknowledged.The calculations were performed using the supercomputers at Tsinghua National Laboratory for Information Science and Technology,the Computational Chemistry Laboratory of the Department of Chemistry under the Tsinghua Xuetang Talents Program,and the Supercomputer Center of the Southern University of Science and Technology.
文摘While heterogeneous single-atom catalysts(SACs)have achieved great success in the past decade,their application is potentially limited by their simplistic single-atom active centers,which make single-cluster catalysts(SCCs)a natural extension in the domain of heterogeneous catalysis.SCCs with precise numbers of atoms and structural configurations possess SAC merits,yet have greater potential for catalyzing complex reactions and/or bulky reactants.Through systematic quantum-chemical studies and computational screening,we report here the rational design of transition metal three-atom clusters anchored on graphdiyne(GDY)as a novel kind of stable SCC with great promise for efficient and atomically precise heterogenous catalysis.By investigating their structure and catalytic performance for the oxygen reduction reaction,the hydrogen evolution reaction,and the CO_(2)reduction reaction,we have provided theoretical guidelines for their potential applications as heterogeneous catalysts.These GDY-supported three-atom SCCs provide an ideal benchmark scaffold for rational design of atomically precise heterogeneous catalysts for industrially important chemical reactions.
基金the National Key Research and Development Program of China(2016YFC1301900)the National Natural Science Foundation of China(81970213,81870218,and 81770373)the Subject Booster Program from Xijing Hospital,the Fourth Military Medical University(XJZT18M L13).
文摘Background::Acute type A aortic dissection(ATAAD)and acute type A intramural hematoma(ATAIMH)are life-threatening diseases with high mortality.To better understand their clinical features in the Chinese population,we analyzed the data from the first Registry of Aortic Dissection in China(Sino-RAD)to promote the understanding and management of the diseases.Methods::All patients with ATAAD and ATAIMH enrolled in Sino-RAD from January 1,2012 to December 31,2016 were involved.The data of patients’selection,history,symptoms,management,outcomes,and postoperation complications were analyzed in the study.The continuous variables were compared using the Student’s t test for normal distributions and the Mann-Whitney U test for non-normal distributions.Categorical variables were compared using the Chi-square test or Fisher exact test.Results::A total of 1582 patients with ATAAD and 130 patients with ATAIMH were included.The mean age of all patients was 48.4 years.Patients with ATAAD were significantly younger than patients with ATAIMH(48.9 years vs.55.6 years,P<0.001).For the total cohort,males were dominant,but the male ratio of patients with ATAAD was significantly higher compared to those with ATAIMH(P=0.01).The time range from the onset of symptom to hospitalization was 2.0 days.More patients of ATAIMH had hypertension than that of ATAAD(82.3%vs.67.6%,P<0.05).Chest and back pain were the most common clinical symptoms.Computerized tomography(CT)was the most common initial diagnostic imaging modality.84.7%received surgical treatment and in-hospital mortality was 5.3%.Patients with ATAAD mainly received surgical treatment(89.6%),while most patients with ATAIMH received medical treatment(39.2%)or endovascular repair(35.4%).Conclusions::Our study suggests that doctors should comprehensively use clinical examination and genetic background screening for patients with ATAAD and ATAIMH and further shorten the time range from symptoms onset to intervention,achieving early diagnosis and treatment,thereby reducing the mortality rate of patients with aortic dissection in China.We should standardize the procedures of aortic dissection treatment and improve people’s understanding.Meanwhile,the curing and transferring efficiency should also be improved.
文摘The magnetic properties and magnetocaloric effect of an antiferromagnetic/ferromagnetic(AFM/FM)BiFeO_(3)/Co bilayer with mixed-spin(5/2,3/2)have been studied based on Monte Carlo simulation.The magnetization,susceptibility,and critical temperature are investigated under various exchange couplings and an external magnetic field.In particular,the influence of exchange couplings and an external magnetic field on the magnetic entropy change,adiabatic temperature change,and the relative cooling power(RCP)are studied.The simulation results indicated that the decrease of the exchange coupling and the increase of external magnetic fields can cause an increase of magnetic entropy change,adiabatic temperature change,and RCP.In addition,the hysteresis loops of the system are presented for different exchange couplings and temperatures.
基金supported by the National Natural Science Foundation of China and the Civil Aviation Administration of China (No.61079010)the financial supports of the Science and Technology Innovation Guide Funds of Civil Aviation Administration of China (2014)the Significant Preresearch Funds of Civil Aviation University of China (No.3122013P001)
文摘Mesoporous,hollow Zn O microspheres were synthesized via a hydrothermal method,using glycerol and zinc acetate as the starting materials.XRD and FESEM analysis showed that the surface morphology of the spheres with a Wurtzite structure could be reasonably adjusted by varying the weight ratio(Rw) of Zn(CH3COO)2 2H2O:H2O:C3H8O3.The responses of the gas sensor based on the spheres to 100 ppm ethanol and 100 ppm acetone are 18.9 and 10.4,respectively.The response and recovery times of the sensor to ethanol and acetone are 2 s and 3 s,3 s and 5 s,respectively.The hollow spheres show an intense UV emission at 392 nm and a broad blue-green emission at 488 nm.Interestingly,a light trapping phenomenon is revealed by UV emission and scattering measurements on the microspheres,which can be attributed to the mesoporous shell and hollow structure of the microsphere.