In 2009,the World Health Organization included snakebite on the list of neglected tropical diseases,acknowledging it as a common occupational hazard for farmers,plantation workers,and others,causing tens of thousands ...In 2009,the World Health Organization included snakebite on the list of neglected tropical diseases,acknowledging it as a common occupational hazard for farmers,plantation workers,and others,causing tens of thousands of deaths and chronic physical disabilities every year.This guideline aims to provide practical information to help clinical professionals evaluate and treat snakebite victims.These recommendations are based on clinical experience and clinical research evidence.This guideline focuses on the following topics:snake venom,clinical manifestations,auxiliary examination,diagnosis,treatments,and prevention.展开更多
Tweek atmospherics are extremely low frequency and very low frequency pulse signals with frequency dispersion characteristics that originate from lightning discharges and that propagate in the Earth–ionosphere wavegu...Tweek atmospherics are extremely low frequency and very low frequency pulse signals with frequency dispersion characteristics that originate from lightning discharges and that propagate in the Earth–ionosphere waveguide over long distances.In this study,we developed an automatic method to recognize tweek atmospherics and diagnose the lower ionosphere based on the machine learning method.The differences(automatic−manual)in each ionosphere parameter between the automatic method and the manual method were−0.07±2.73 km,0.03±0.92 cm^(−3),and 91±1,068 km for the ionospheric reflection height(h),equivalent electron densities at reflection heights(Ne),and propagation distance(d),respectively.Moreover,the automatic method is capable of recognizing higher harmonic tweek sferics.The evaluation results of the model suggest that the automatic method is a powerful tool for investigating the long-term variations in the lower ionosphere.展开更多
Veno-arterial extracorporeal membrane oxygenation(VA-ECMO) is indicated in patients with severe cardiogenic shock.During extracorporeal membrane oxygenation(ECMO) use,systemic anticoagulation is generally used to ensu...Veno-arterial extracorporeal membrane oxygenation(VA-ECMO) is indicated in patients with severe cardiogenic shock.During extracorporeal membrane oxygenation(ECMO) use,systemic anticoagulation is generally used to ensure the normal functioning of ECMO.Hemorrhage and thrombosis are two important complications of ECMO.However,despite adequate anticoagulation,some patients still experience thrombosis,such as inferior vena cava thrombosis (IVCT),after the removal of ECMO.^([1,2])A metaanalysis showed that the incidence of venous thrombosis during ECMO treatment is approximately 10%,^([3])but IVCT is rarely reported.We report two cases of IVCT after the removal of VA-ECMO cannulas.展开更多
Background:Since the trauma knowledge of trauma providers correlates with the outcomes of injured patients,this study aims to assess the socio-demographic characteristics and levels of trauma knowledge of trainees in ...Background:Since the trauma knowledge of trauma providers correlates with the outcomes of injured patients,this study aims to assess the socio-demographic characteristics and levels of trauma knowledge of trainees in the China trauma care training(CTCT)program in addition to their post-course test results to provide support for the development of trauma care training programs and trauma systems in China.Methods:A cross-sectional study was conducted by collecting demographic information,hospital-related information and trauma knowledge of the trainees from 19 regions in China.All participants were assessed by questionnaires collecting the socio-demographic data,the trauma care knowledge levels and the information of the hospitals.Results:There were 955 males(78.9%)and 256 females(21.1%)enrolled.Among them,854 were physicians(70.5%),357 were registered nurses(29.5%).In addition,64 of them also played an administrative role in the hospitals(5.3%).The score of the trainees who were members of the emergency department staff(72.59±14.13)was the highest among the scores of all the personnel surveyed,followed by those of the trainees from the intensive care unit(ICU)(71.17±12.72),trauma surgery department(67.26±13.81),orthopedics department(70.36±14.48),general surgery department(69.91±14.79)and other departments(69.93±16.91),P=0.031.The score of the professors(73.09±15.05)was higher than those of the associate professors(72.40±14.71),lecturers(70.07±14.25)and teaching assistants(67.58±15.16),P<0.0001.The score of the individuals who attended experts’trauma lectures(72.22±14.45)was higher than that of individuals who did not attend the lectures(69.33±15.17),P=0.001.The mean scores before and after the training were 71.02±14.82 and 84.24±13.77,respectively,P<0.001.The mean score of trauma knowledge after the training of trainees from different provinces and with different educational backgrounds was higher than that before the training,with a statistically significant difference(P<0.05).Conclusions:The level of trauma knowledge of trauma care providers was associated with their department,professional position and previous participation in related academic conferences.Trauma care experience and participation in academic lectures and training program including CTCT may effectively improve individuals’level of trauma knowledge.展开更多
It is generally accepted that herding behavior and overconfidence behavior are unrelated or even mutually exclusive.However,these behaviors can both lead to some similar market anomalies,such as excessive trading volu...It is generally accepted that herding behavior and overconfidence behavior are unrelated or even mutually exclusive.However,these behaviors can both lead to some similar market anomalies,such as excessive trading volume and volatility in the stock market.Due to the limitation of traditional time series analysis,we try to study whether there exists network relevance between the investor’s herding behavior and overconfidence behavior based on the complex network method.Since the investor’s herding behavior is based on market trends and overconfidence behavior is based on past performance,we convert the time series data of market trends into a market network and the time series data of the investor’s past judgments into an investor network.Then,we update these networks as new information arrives at the market and show the weighted in-degrees of the nodes in the market network and the investor network can represent the herding degree and the confidence degree of the investor,respectively.Using stock transaction data of Microsoft,US S&P 500 stock index,and China Hushen 300 stock index,we update the two networks and find that there exists a high similarity of network topological properties and a significant correlation of node parameter sequences between the market network and the investor network.Finally,we theoretically derive and conclude that the investor’s herding degree and confidence degree are highly related to each other when there is a clear market trend.展开更多
1.Introduction Sudden cardiac death(SCD)refers to sudden death due to a variety of cardiac causes.It is manifested as a sudden loss of consciousness,cardiac arrest,and respiratory arrest and generally shows early symp...1.Introduction Sudden cardiac death(SCD)refers to sudden death due to a variety of cardiac causes.It is manifested as a sudden loss of consciousness,cardiac arrest,and respiratory arrest and generally shows early symptoms that are atypical and not easily detected[1].According to a recent study,nearly 544000 patients suffer from SCD every year in China[2].展开更多
Currently,faced with the rapid development of information technology and increasing competition of the global economy,many countries have been very concerned about the issues of informatization concerning agriculture ...Currently,faced with the rapid development of information technology and increasing competition of the global economy,many countries have been very concerned about the issues of informatization concerning agriculture and rural areas. The level of informatization in the developed countries has been universally high,and some developing countries are also highly concerned about how to actively promote the rural market information service. With the increasing level of China's economic development,agriculture and rural economy have placed a growing demand on informatization. From the overall perspective of agricultural and rural informatization,this paper gives a detailed analysis of current situation,goals,tasks and constraints about agricultural and rural informatization construction,and finally makes the corresponding recommendations.展开更多
A new two-step spark plasma sintering(TSS)process with low-temperature pre-sintering and high-temperature final sintering has been successfully applied to prepare the tungsten-particle(Wp)-reinforced bulk metallic gla...A new two-step spark plasma sintering(TSS)process with low-temperature pre-sintering and high-temperature final sintering has been successfully applied to prepare the tungsten-particle(Wp)-reinforced bulk metallic glass composites(Wp/BMGCs).Compared to normal spark plasma sintering(NS),the densification rate and relative density of Wp/BMGCs can be improved by selecting TSS with appropriate sintering pressure in the low temperature pre-sintering stage.However,the compressive strength and plastic strain of 30%Wp/BMGCs prepared by TSS are both higher than those of the samples prepared by NS.The TSS process can significantly enhance the compressive strength of 30%Wp/BMGCs by 12%and remarkably increase the plastic strain by 50%,while the trend is completely opposite for 50%Wp/BMGCs.Quasi-in situ experiments and finite element simulations reveal that uneven temperature distribution among particles during low-temperature pre-sintering causes local overheating at contact points between particles,accelerating formation of sintering neck between particles and plastic deformation of Wp.When the volume fraction of Wp is low,TSS can improve the interface bonding between particles by increasing the number of sintering necks.This makes the fracture mode of Wp/BMGCs being predominantly transgranular fracture.However,as the volume fraction of Wp increases,the adverse effects of Wp plastic deformation are becoming more and more prominent.The aggregated Wp tends to form a solid"cage structure"that hinders the bonding between particles at the interface;correspondingly,the fracture behavior of Wp/BMGCs is mainly dominated by intergranular fracture.Additionally,reducing the sintering pressure during the low-temperature pre-sintering stage of TSS has been shown to effectively decrease plastic deformation in Wp,resulting in a higher degree of densification and better mechanical properties.展开更多
Hot deformation is a commonly employed processing technique to enhance the ductility and workability of Mg alloy.However,the hot deformation of Mg alloy is highly sensitive to factors such as temperature,strain rate,a...Hot deformation is a commonly employed processing technique to enhance the ductility and workability of Mg alloy.However,the hot deformation of Mg alloy is highly sensitive to factors such as temperature,strain rate,and strain,leading to complex flow behavior and an exceptionally narrow processing window for Mg alloy.To overcome the shortcomings of the conventional Arrhenius-type(AT)model,this study developed machine learning-based Arrhenius-type(ML-AT)models by combining the genetic algorithm(GA),particle swarm optimization(PSO),and artificial neural network(ANN).Results indicated that when describing the flow behavior of the AQ80 alloy,the PSO-ANN-AT model demonstrates the most prominent prediction accuracy and generalization ability among all ML-AT and AT models.Moreover,an activation energy-processing(AEP)map was established using the reconstructed flow stress and activation energy fields based on the PSO-ANN-AT model.Experimental validations revealed that this AEP map exhibits superior predictive capability for microstructure evolution compared to the one established by the traditional interpolation methods,ultimately contributing to the precise determination of the optimum processing window.These findings provide fresh insights into the accurate constitutive description and workability characterization of Mg alloy during hot deformation.展开更多
Background:This study aimed to evaluate the effects of standard rescue procedure (SRP) in improving severe trauma treatments in China.Methods:This study was conducted in 12 hospitals located in geographically and ...Background:This study aimed to evaluate the effects of standard rescue procedure (SRP) in improving severe trauma treatments in China.Methods:This study was conducted in 12 hospitals located in geographically and industrially different cities in China.A standard procedure on severe trauma rescue was established as a general rule for staff training and patient treatment.A regional network (system) efficiently integrating prehospital rescue,emergency room treatments,and hospital specialist treatments was built under the rule for information sharing and improving severe trauma treatments.Treatment outcomes were compared between before and I year after the implementation of the SRP.Results:The outcomes of a total of 74,615 and 12,051 trauma cases were collected from 12 hospitals before and after the implementation of the SRP.Implementation of the SRP led to efficient cooperation and information sharing of different treatment services.The emergency response time,prehospital transit time,emergency rescue time,consultation call time,and mortality rate of patients were 24.24 ± 4.32 min,45.69 ± 3.89 min,6.38 ± 1.05 min,17.53 ± 0.72 min,and 33.82% ± 3.87% (n =441),respectively,before the implementation of the standardization and significantly reduced to 10.11 ± 3.21 min,22.39 ± 4.32 min,3.26 ± 0.89 min,3.45 ± 0.45 min,and 20.49% ± 3.11%,separately (n =495,P 〈 0.05) after that.Conclusions:Staff training and SRP can significantly improve the efficiency of severe trauma treatments in China.展开更多
Purpose:To establish a severe blast lung injury model of goats and investigate the feasibility of lung ultrasonic score in the evaluation of blast lung injury.Methods:Twenty female healthy goats were randomly divided ...Purpose:To establish a severe blast lung injury model of goats and investigate the feasibility of lung ultrasonic score in the evaluation of blast lung injury.Methods:Twenty female healthy goats were randomly divided into three groups by different driving pressures:4.0 MPa group(n=4),4.5 MPa group(n=12)and 5.0 MPa group(n=4).The severe blast lung injury model of goats was established using a BST-I bio-shock tube.Vital signs(respiration,heart rate and blood pressure),lung ultrasound score(LUS),PO2/FiO2 and extravascular lung water(EVLW)were measured before injury(0 h)and at 0.5 h,3 h,6 h,9 h,12 h after injury.Computed tomography scan was performed before injury(0 h)and at 12 h after injury for dynamic monitoring of blast lung injury and measurement of lung volume.The correlation of LUS with PaO2/FiO2,EVLW,and lung injury ratio(lesion volume/total lung volume*100%)was analyzed.All animals were sacrificed at 12 h after injury for gross observation of lung injury and histopathological examination.Statistical analysis was performed by the SPSS 22.0 software.The measurement data were expressed as mean±standard deviation.The means of two samples were compared using independent-sample t-test.Pearson correlation analysis was conducted.Results:(1)At 12 h after injury,the mortality of goats was 0,41.67% and 100%in the 4.0 Mpa,4.5 MPa and 5.0 MPa groups,respectively;the area of pulmonary hemorrhage was 20.00%±13.14% in the 4.0 Mpa group and 42.14%±15.33% in the 4.5 MPa group.A severe lung shock injury model was established under the driving pressure of 4.5 MPa.(2)The respiratory rate,heart rate,LUS and EVLW were significantly increased,while PaO2/FiO2 was significantly reduced immediately after injury,and then they gradually recovered and became stabilized at 3 h after injury.(3)LUS was positively correlated with EVLW(3 h:r=-0.597,6 h:r=-0.698,9 h:r=-0.729;p<0.05)and lung injury ratio(12 h:r=-0.884,p<0.05),negatively correlated with PaO2/FiO2(3 h:r=-0.871,6 h:r=-0.637,9 h:r=-0.658;p<0.05).Conclusion:We established a severe blast lung injury model of goats using the BST-I bio-shock tube under the driving pressure of 4.5 MPa and confirmed that ultrasound can be used for quick evaluation and dynamic monitoring of blast lung injury.展开更多
High entropy metallic glasses(MGs) have attracted tremendous attentions owing to high entropy that benefits the probing of new MG-forming systems. However, the micro-formability of high entropy MGs is lack of invest...High entropy metallic glasses(MGs) have attracted tremendous attentions owing to high entropy that benefits the probing of new MG-forming systems. However, the micro-formability of high entropy MGs is lack of investigation in comparison with these conventional MG counterparts, which is crucial to the development of this kind of metallic alloys. In this work, the thermoplastic mciro-formability of TiZrHfNiCuBe high entropy MG was systemically investigated. Time-Temperature-Transformation(TTT)curve was first constructed based on isothermal crystallization experiments, which provides thermoplastic processing time of the supercooled high entropy MGs. By comparison with the deformation map,Newtonian flow was found beneficial to the thermoplastic formability. While the thermoplastic forming becomes arduous with reducing mould size to tens micrometer, because of the strong supercooled TiZrHfNiCuBe high entropy MG(fragility = 27). Fortunately, the micro-formability of TiZrHfNiCuBe high entropy MG could be improved by vibration loading, as demonstrated by finite-element-method simulation. Our findings not only systemically evaluate the thermoplastic micro-formability of high entropy MG, but also provide fundamental understanding of the phenomenon.展开更多
Trauma is a life-threatening "modern disease". The outcomes could only be optimized by cost-efficient and prompt trauma care, which embarks on the improvement of essential capacities and conceptual revolution in add...Trauma is a life-threatening "modern disease". The outcomes could only be optimized by cost-efficient and prompt trauma care, which embarks on the improvement of essential capacities and conceptual revolution in addition to the disruptive innovation of the trauma care system. According to experiences from the developed countries, systematic trauma care training is the cornerstone of the generalization and the improvement on the trauma care, such as the Advance Trauma Life Support (ATLS). Currently, the pre-hospital emergency medical services (EMS) has been one of the essential elements of infrastructure of health services in China, which is also fundamental to the trauma care system. Hereby, the China Trauma Care Training (CTCT) with independent intellectual property rights has been initiated and launched by the Chinese Trauma Surgeon Association to extend the up-to-date concepts and techniques in the field of trauma care as well to reinforce the generally well-accepted standardized protocols in the practices. This article reviews the current status of the trauma care system as well as the trauma care training.展开更多
In the present study,we investigate the crystal structure of high-entropy alloys(HEAs)in the form of CoFe2NiMn0.3AlCux(x=0.25,0.50,0.75,and 1.00)and their mechanical and magnetic properties.The CoFe2NiMn0.3AlCux alloy...In the present study,we investigate the crystal structure of high-entropy alloys(HEAs)in the form of CoFe2NiMn0.3AlCux(x=0.25,0.50,0.75,and 1.00)and their mechanical and magnetic properties.The CoFe2NiMn0.3AlCux alloys are composed of a mixture of a body-centered cubic(BCC)and a face-centered cubic(FCC)solid solution.The increased amounts of copper(Cu)boost both alloy strength and plastic ductility.The CoFe2 NiMn0.3AlCu1.0 HEAs demonstrate excellent mechanical properties,such as a high strength of 1832 MPa and a large plastic ductility of 22.38%.Magnetic property measurements on this alloy system indicated high saturated magnetization and high coercivity.The coercivity of the tested alloys lies in the range between 40 and 182 Oe,suggesting that the alloys have semi-hard magnetic properties.This study suggests that the present CoFe2NiMn0.3AlCux HEAs could serve as potential candidates for soft magnets in electromagnetic applications.展开更多
基金supported by the National Science Foundation of China(82160647)Hainan Clinical Medical Research Center Project(LCYX202310)+1 种基金Hainan Provincial Major Science and Technology Projects(ZDKJ202004)CAMS Innovation Fund for Medical Sciences(2019-I2M-5-023).
文摘In 2009,the World Health Organization included snakebite on the list of neglected tropical diseases,acknowledging it as a common occupational hazard for farmers,plantation workers,and others,causing tens of thousands of deaths and chronic physical disabilities every year.This guideline aims to provide practical information to help clinical professionals evaluate and treat snakebite victims.These recommendations are based on clinical experience and clinical research evidence.This guideline focuses on the following topics:snake venom,clinical manifestations,auxiliary examination,diagnosis,treatments,and prevention.
基金financially supported by the National Natural Science Foundation of China(No.51805181)the National Science Fund for Distinguished Young Scholars of China(No.51725504)the Fundamental Research Funds for the Central Universities of China(No.2020kfy XJJS049)。
基金supported by the Chinese Academy of Sciences(CAS)Project of Stable Support for Youth Team in Basic Research Field(Grant No.YSRR-018)the National Key R&D Program of China(Grant No.2019YFC1510103)+1 种基金the National Natural Science Foundation of China(Grant Nos.41875006 and U1938115)the Chinese Meridian Project,and the International Partnership Program of CAS(Grant No.183311KYSB20200003).
文摘Tweek atmospherics are extremely low frequency and very low frequency pulse signals with frequency dispersion characteristics that originate from lightning discharges and that propagate in the Earth–ionosphere waveguide over long distances.In this study,we developed an automatic method to recognize tweek atmospherics and diagnose the lower ionosphere based on the machine learning method.The differences(automatic−manual)in each ionosphere parameter between the automatic method and the manual method were−0.07±2.73 km,0.03±0.92 cm^(−3),and 91±1,068 km for the ionospheric reflection height(h),equivalent electron densities at reflection heights(Ne),and propagation distance(d),respectively.Moreover,the automatic method is capable of recognizing higher harmonic tweek sferics.The evaluation results of the model suggest that the automatic method is a powerful tool for investigating the long-term variations in the lower ionosphere.
文摘Veno-arterial extracorporeal membrane oxygenation(VA-ECMO) is indicated in patients with severe cardiogenic shock.During extracorporeal membrane oxygenation(ECMO) use,systemic anticoagulation is generally used to ensure the normal functioning of ECMO.Hemorrhage and thrombosis are two important complications of ECMO.However,despite adequate anticoagulation,some patients still experience thrombosis,such as inferior vena cava thrombosis (IVCT),after the removal of ECMO.^([1,2])A metaanalysis showed that the incidence of venous thrombosis during ECMO treatment is approximately 10%,^([3])but IVCT is rarely reported.We report two cases of IVCT after the removal of VA-ECMO cannulas.
基金support by grants from the“Chongqing Science and Technology Benefiting project”(cstc2016kjhmpt1001)research project from the State Key Laboratory of Trauma,Burns and Combined Injury(SKLZZ201603)。
文摘Background:Since the trauma knowledge of trauma providers correlates with the outcomes of injured patients,this study aims to assess the socio-demographic characteristics and levels of trauma knowledge of trainees in the China trauma care training(CTCT)program in addition to their post-course test results to provide support for the development of trauma care training programs and trauma systems in China.Methods:A cross-sectional study was conducted by collecting demographic information,hospital-related information and trauma knowledge of the trainees from 19 regions in China.All participants were assessed by questionnaires collecting the socio-demographic data,the trauma care knowledge levels and the information of the hospitals.Results:There were 955 males(78.9%)and 256 females(21.1%)enrolled.Among them,854 were physicians(70.5%),357 were registered nurses(29.5%).In addition,64 of them also played an administrative role in the hospitals(5.3%).The score of the trainees who were members of the emergency department staff(72.59±14.13)was the highest among the scores of all the personnel surveyed,followed by those of the trainees from the intensive care unit(ICU)(71.17±12.72),trauma surgery department(67.26±13.81),orthopedics department(70.36±14.48),general surgery department(69.91±14.79)and other departments(69.93±16.91),P=0.031.The score of the professors(73.09±15.05)was higher than those of the associate professors(72.40±14.71),lecturers(70.07±14.25)and teaching assistants(67.58±15.16),P<0.0001.The score of the individuals who attended experts’trauma lectures(72.22±14.45)was higher than that of individuals who did not attend the lectures(69.33±15.17),P=0.001.The mean scores before and after the training were 71.02±14.82 and 84.24±13.77,respectively,P<0.001.The mean score of trauma knowledge after the training of trainees from different provinces and with different educational backgrounds was higher than that before the training,with a statistically significant difference(P<0.05).Conclusions:The level of trauma knowledge of trauma care providers was associated with their department,professional position and previous participation in related academic conferences.Trauma care experience and participation in academic lectures and training program including CTCT may effectively improve individuals’level of trauma knowledge.
基金Project supported by the Youth Program of the National Social Science Foundation of China(Grant No.18CJY057)。
文摘It is generally accepted that herding behavior and overconfidence behavior are unrelated or even mutually exclusive.However,these behaviors can both lead to some similar market anomalies,such as excessive trading volume and volatility in the stock market.Due to the limitation of traditional time series analysis,we try to study whether there exists network relevance between the investor’s herding behavior and overconfidence behavior based on the complex network method.Since the investor’s herding behavior is based on market trends and overconfidence behavior is based on past performance,we convert the time series data of market trends into a market network and the time series data of the investor’s past judgments into an investor network.Then,we update these networks as new information arrives at the market and show the weighted in-degrees of the nodes in the market network and the investor network can represent the herding degree and the confidence degree of the investor,respectively.Using stock transaction data of Microsoft,US S&P 500 stock index,and China Hushen 300 stock index,we update the two networks and find that there exists a high similarity of network topological properties and a significant correlation of node parameter sequences between the market network and the investor network.Finally,we theoretically derive and conclude that the investor’s herding degree and confidence degree are highly related to each other when there is a clear market trend.
基金Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences(No.2019-I2M-5-023)Hainan Provincial Science and Technology Major Project(No.ZDKJ201804)+2 种基金National Natural Science Foundation of China(No.81871611)National Natural Science Foundation of China(No.81760352)Project of Hainan Provincial Department of Education(No.Hnjg2019ZD-16)
文摘1.Introduction Sudden cardiac death(SCD)refers to sudden death due to a variety of cardiac causes.It is manifested as a sudden loss of consciousness,cardiac arrest,and respiratory arrest and generally shows early symptoms that are atypical and not easily detected[1].According to a recent study,nearly 544000 patients suffer from SCD every year in China[2].
基金Supported by Business Management Cultivation Discipline of Southwest University Rongchang Campus
文摘Currently,faced with the rapid development of information technology and increasing competition of the global economy,many countries have been very concerned about the issues of informatization concerning agriculture and rural areas. The level of informatization in the developed countries has been universally high,and some developing countries are also highly concerned about how to actively promote the rural market information service. With the increasing level of China's economic development,agriculture and rural economy have placed a growing demand on informatization. From the overall perspective of agricultural and rural informatization,this paper gives a detailed analysis of current situation,goals,tasks and constraints about agricultural and rural informatization construction,and finally makes the corresponding recommendations.
基金financially supported by the National Natural Science Foundation of China(Nos.52371154,52090043,52175371 and 52271147)Guangdong Basic and Applied Basic Research Foundation(No.2023A1515012158)+1 种基金the Knowledge Innovation Program of Wuhan-Basic Researchthe Fundamental Research Funds for the Central Universities(No.2021GCRC003)。
文摘A new two-step spark plasma sintering(TSS)process with low-temperature pre-sintering and high-temperature final sintering has been successfully applied to prepare the tungsten-particle(Wp)-reinforced bulk metallic glass composites(Wp/BMGCs).Compared to normal spark plasma sintering(NS),the densification rate and relative density of Wp/BMGCs can be improved by selecting TSS with appropriate sintering pressure in the low temperature pre-sintering stage.However,the compressive strength and plastic strain of 30%Wp/BMGCs prepared by TSS are both higher than those of the samples prepared by NS.The TSS process can significantly enhance the compressive strength of 30%Wp/BMGCs by 12%and remarkably increase the plastic strain by 50%,while the trend is completely opposite for 50%Wp/BMGCs.Quasi-in situ experiments and finite element simulations reveal that uneven temperature distribution among particles during low-temperature pre-sintering causes local overheating at contact points between particles,accelerating formation of sintering neck between particles and plastic deformation of Wp.When the volume fraction of Wp is low,TSS can improve the interface bonding between particles by increasing the number of sintering necks.This makes the fracture mode of Wp/BMGCs being predominantly transgranular fracture.However,as the volume fraction of Wp increases,the adverse effects of Wp plastic deformation are becoming more and more prominent.The aggregated Wp tends to form a solid"cage structure"that hinders the bonding between particles at the interface;correspondingly,the fracture behavior of Wp/BMGCs is mainly dominated by intergranular fracture.Additionally,reducing the sintering pressure during the low-temperature pre-sintering stage of TSS has been shown to effectively decrease plastic deformation in Wp,resulting in a higher degree of densification and better mechanical properties.
基金supported by the National Natural Science Foundation of China(Grant Nos.52305361,51775194,52090043)China Postdoctoral Science Foundation(2023M741245)the National Key Research and Development Program of China(2022YFB3706903).
文摘Hot deformation is a commonly employed processing technique to enhance the ductility and workability of Mg alloy.However,the hot deformation of Mg alloy is highly sensitive to factors such as temperature,strain rate,and strain,leading to complex flow behavior and an exceptionally narrow processing window for Mg alloy.To overcome the shortcomings of the conventional Arrhenius-type(AT)model,this study developed machine learning-based Arrhenius-type(ML-AT)models by combining the genetic algorithm(GA),particle swarm optimization(PSO),and artificial neural network(ANN).Results indicated that when describing the flow behavior of the AQ80 alloy,the PSO-ANN-AT model demonstrates the most prominent prediction accuracy and generalization ability among all ML-AT and AT models.Moreover,an activation energy-processing(AEP)map was established using the reconstructed flow stress and activation energy fields based on the PSO-ANN-AT model.Experimental validations revealed that this AEP map exhibits superior predictive capability for microstructure evolution compared to the one established by the traditional interpolation methods,ultimately contributing to the precise determination of the optimum processing window.These findings provide fresh insights into the accurate constitutive description and workability characterization of Mg alloy during hot deformation.
文摘Background:This study aimed to evaluate the effects of standard rescue procedure (SRP) in improving severe trauma treatments in China.Methods:This study was conducted in 12 hospitals located in geographically and industrially different cities in China.A standard procedure on severe trauma rescue was established as a general rule for staff training and patient treatment.A regional network (system) efficiently integrating prehospital rescue,emergency room treatments,and hospital specialist treatments was built under the rule for information sharing and improving severe trauma treatments.Treatment outcomes were compared between before and I year after the implementation of the SRP.Results:The outcomes of a total of 74,615 and 12,051 trauma cases were collected from 12 hospitals before and after the implementation of the SRP.Implementation of the SRP led to efficient cooperation and information sharing of different treatment services.The emergency response time,prehospital transit time,emergency rescue time,consultation call time,and mortality rate of patients were 24.24 ± 4.32 min,45.69 ± 3.89 min,6.38 ± 1.05 min,17.53 ± 0.72 min,and 33.82% ± 3.87% (n =441),respectively,before the implementation of the standardization and significantly reduced to 10.11 ± 3.21 min,22.39 ± 4.32 min,3.26 ± 0.89 min,3.45 ± 0.45 min,and 20.49% ± 3.11%,separately (n =495,P 〈 0.05) after that.Conclusions:Staff training and SRP can significantly improve the efficiency of severe trauma treatments in China.
基金supported by State Key Laboratory of Trauma,Burns and Combined Injury Project(No.SKLYQ201901,No.SKLKF201801).
文摘Purpose:To establish a severe blast lung injury model of goats and investigate the feasibility of lung ultrasonic score in the evaluation of blast lung injury.Methods:Twenty female healthy goats were randomly divided into three groups by different driving pressures:4.0 MPa group(n=4),4.5 MPa group(n=12)and 5.0 MPa group(n=4).The severe blast lung injury model of goats was established using a BST-I bio-shock tube.Vital signs(respiration,heart rate and blood pressure),lung ultrasound score(LUS),PO2/FiO2 and extravascular lung water(EVLW)were measured before injury(0 h)and at 0.5 h,3 h,6 h,9 h,12 h after injury.Computed tomography scan was performed before injury(0 h)and at 12 h after injury for dynamic monitoring of blast lung injury and measurement of lung volume.The correlation of LUS with PaO2/FiO2,EVLW,and lung injury ratio(lesion volume/total lung volume*100%)was analyzed.All animals were sacrificed at 12 h after injury for gross observation of lung injury and histopathological examination.Statistical analysis was performed by the SPSS 22.0 software.The measurement data were expressed as mean±standard deviation.The means of two samples were compared using independent-sample t-test.Pearson correlation analysis was conducted.Results:(1)At 12 h after injury,the mortality of goats was 0,41.67% and 100%in the 4.0 Mpa,4.5 MPa and 5.0 MPa groups,respectively;the area of pulmonary hemorrhage was 20.00%±13.14% in the 4.0 Mpa group and 42.14%±15.33% in the 4.5 MPa group.A severe lung shock injury model was established under the driving pressure of 4.5 MPa.(2)The respiratory rate,heart rate,LUS and EVLW were significantly increased,while PaO2/FiO2 was significantly reduced immediately after injury,and then they gradually recovered and became stabilized at 3 h after injury.(3)LUS was positively correlated with EVLW(3 h:r=-0.597,6 h:r=-0.698,9 h:r=-0.729;p<0.05)and lung injury ratio(12 h:r=-0.884,p<0.05),negatively correlated with PaO2/FiO2(3 h:r=-0.871,6 h:r=-0.637,9 h:r=-0.658;p<0.05).Conclusion:We established a severe blast lung injury model of goats using the BST-I bio-shock tube under the driving pressure of 4.5 MPa and confirmed that ultrasound can be used for quick evaluation and dynamic monitoring of blast lung injury.
基金supported by the National Natural Science Foundation of China [Grant Nos. 51671090, 51725504, 51435007]the funds of the the State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology [number AWJ-17M06]
文摘High entropy metallic glasses(MGs) have attracted tremendous attentions owing to high entropy that benefits the probing of new MG-forming systems. However, the micro-formability of high entropy MGs is lack of investigation in comparison with these conventional MG counterparts, which is crucial to the development of this kind of metallic alloys. In this work, the thermoplastic mciro-formability of TiZrHfNiCuBe high entropy MG was systemically investigated. Time-Temperature-Transformation(TTT)curve was first constructed based on isothermal crystallization experiments, which provides thermoplastic processing time of the supercooled high entropy MGs. By comparison with the deformation map,Newtonian flow was found beneficial to the thermoplastic formability. While the thermoplastic forming becomes arduous with reducing mould size to tens micrometer, because of the strong supercooled TiZrHfNiCuBe high entropy MG(fragility = 27). Fortunately, the micro-formability of TiZrHfNiCuBe high entropy MG could be improved by vibration loading, as demonstrated by finite-element-method simulation. Our findings not only systemically evaluate the thermoplastic micro-formability of high entropy MG, but also provide fundamental understanding of the phenomenon.
文摘Trauma is a life-threatening "modern disease". The outcomes could only be optimized by cost-efficient and prompt trauma care, which embarks on the improvement of essential capacities and conceptual revolution in addition to the disruptive innovation of the trauma care system. According to experiences from the developed countries, systematic trauma care training is the cornerstone of the generalization and the improvement on the trauma care, such as the Advance Trauma Life Support (ATLS). Currently, the pre-hospital emergency medical services (EMS) has been one of the essential elements of infrastructure of health services in China, which is also fundamental to the trauma care system. Hereby, the China Trauma Care Training (CTCT) with independent intellectual property rights has been initiated and launched by the Chinese Trauma Surgeon Association to extend the up-to-date concepts and techniques in the field of trauma care as well to reinforce the generally well-accepted standardized protocols in the practices. This article reviews the current status of the trauma care system as well as the trauma care training.
基金financially supported by the National Natural Science Foundation of China(Nos.51301125,51971166,and 51904218)the Natural Science Basic Research Program of Shaanxi Province(No.2020JM-557)the State Key Laboratory of Solidification Processing in NWPU(No.SKLSP201811)。
文摘In the present study,we investigate the crystal structure of high-entropy alloys(HEAs)in the form of CoFe2NiMn0.3AlCux(x=0.25,0.50,0.75,and 1.00)and their mechanical and magnetic properties.The CoFe2NiMn0.3AlCux alloys are composed of a mixture of a body-centered cubic(BCC)and a face-centered cubic(FCC)solid solution.The increased amounts of copper(Cu)boost both alloy strength and plastic ductility.The CoFe2 NiMn0.3AlCu1.0 HEAs demonstrate excellent mechanical properties,such as a high strength of 1832 MPa and a large plastic ductility of 22.38%.Magnetic property measurements on this alloy system indicated high saturated magnetization and high coercivity.The coercivity of the tested alloys lies in the range between 40 and 182 Oe,suggesting that the alloys have semi-hard magnetic properties.This study suggests that the present CoFe2NiMn0.3AlCux HEAs could serve as potential candidates for soft magnets in electromagnetic applications.