The legacy of United States cluster munition use in Laos and Cambodia during the Second Indochina War is residual bomblets that unexpectedly detonate years later, killing and injuring children, farmers, and other civi...The legacy of United States cluster munition use in Laos and Cambodia during the Second Indochina War is residual bomblets that unexpectedly detonate years later, killing and injuring children, farmers, and other civilians. Cluster munitions release dozens of smaller bomblets that rain deadly ammunition on troops, armored tanks, and vegetation, effectively striking broad sections of war zone landscapes in one launch. While many bomblets detonate immediately, others fail to detonate and can lie dormant on the ground for years. The primary objectives of this study were to document the long-term consequences and impacts of the US Air Force bombing of Laos and Cambodia during the Second Indochina War (1959 to 1973). The historical lessons learned by United States should be shared with Russia and Ukraine governments and military. These countries need to discontinue the use of cluster bombs to prevent additional people living along the Russia-Ukraine border from having to live and die with the consequences of unexploded ordnance, including cluster bombs, for the next century.展开更多
Magnesium(Mg)-based implants have been clinically proven to fulfill long-term service requirements,but their passive degradation periods remain to be uncontrollable.Herein,we developed a novel near infrared(NIR)-respo...Magnesium(Mg)-based implants have been clinically proven to fulfill long-term service requirements,but their passive degradation periods remain to be uncontrollable.Herein,we developed a novel near infrared(NIR)-responsive coating on a Mg-Ag-Mn alloy with controllable biodegradation enhanced by air release.The coating exhibits a bi-layered structure,in which the outer layer consists of polycaprolactone(PCL)with the addition of nano-sized polypyrrole(PPy)particles for NIR response,whereas the inner layer is a porous ceramic film produced via plasma electrolytic oxidation(PEO).In particular,the porous structure of PEO film was proposed as a carrier for entrapped air to form the“air bomb”.Without NIR irradiation,the coating possesses a dense and homogeneous microstructure and exhibits excellent long-term durability in saline.Under the NIR irradiation,the PCL resin transforms from a rubbery state to a viscous state promoted by the photothermal action of PPy,while the thermal-expanded air in PEO film escapes from the PCL resin,resulting in macroscopic defects across the coating.This phenomenon leads to a change in the function of Mg alloy from"anti-corrosion"to"biodegradation".This work is expected to provide a new strategy for optimizing the service time of Mg-based implants.展开更多
Bomb cyclones are rapidly deepening extratropical cyclones predominantly found in midlatitude regions.These extreme events are particularly frequent over the North Pacific(NP),posing significant societal and environme...Bomb cyclones are rapidly deepening extratropical cyclones predominantly found in midlatitude regions.These extreme events are particularly frequent over the North Pacific(NP),posing significant societal and environmental risks.Currently,our understanding of the variability of bomb cyclones over the NP remains limited.This study analyzes the variations in multiple NP bomb cyclone characteristics from 1980 onward using four major reanalysis datasets.The results show a weakening trend of bomb cyclones since the beginning of the 21st century,which is characterized by significant reductions in maximum near-surface wind speeds,increases in minimum sea level pressure,and slower deepening rates.Further analysis reveals that the observed weakening trend of bomb cyclones is closely linked to a reduction in maximum 850 hPa Eady growth rate,driven primarily by reduced vertical wind shear within the 30°-45°N latitudinal band.Furthermore,our findings indicate that the Aleutian Low acts to modulate the meridional air temperature gradient over the midlatitude NP,which is corroborated by climate model outputs.This modulation provides a pathway for the Aleutian Low to affect low-level baroclinicity and thus bomb cyclone characteristics.These results have important implications for future projections of bomb cyclone activity over the NP,aiding in risk assessment and mitigating the impacts of these extreme events.展开更多
The sequential dispersing results of aerial cluster bomb are discussed. The ballistic model and the mod- el for impact point distribution of bullets are established. The main factors influencing impact point distribut...The sequential dispersing results of aerial cluster bomb are discussed. The ballistic model and the mod- el for impact point distribution of bullets are established. The main factors influencing impact point distribution are analyzed by numerical simulation. And the feasibility of improving distribution effect through sequential dis- persing is validated. Sequential dispersion and optimized airdrop parameters can help to achieve better battle effec- tiveness.展开更多
On a summer morning in Boqiang Village,tucked beneath the emerald mountains of Fanshi County,Shanxi Province,the Ultra Trail Mount Wutai2025 commenced with the sound of the starting pistol-an event that was much more ...On a summer morning in Boqiang Village,tucked beneath the emerald mountains of Fanshi County,Shanxi Province,the Ultra Trail Mount Wutai2025 commenced with the sound of the starting pistol-an event that was much more than just a competition.As soon as the colorful smoke bombs lit up the sky,some2,000 runners from China and abroad set off to reach one of the country's most sacred Buddhist peaks.Over the past decade,this race has become a fixture on the global running calendar and a symbol of the growing popularity of endurance sports.展开更多
An upsurge of terrorist activity has occurred in the past two decades. As part of this, explosive devices continue to be extensively deployed against civilians in wide-ranging environments. Bombings remain the leading...An upsurge of terrorist activity has occurred in the past two decades. As part of this, explosive devices continue to be extensively deployed against civilians in wide-ranging environments. Bombings remain the leading worldwide cause of civilian fatalities due to terrorism. This demands an understanding of modern terrorist bombing trends to inform mitigation strategy. The objective of this study was to identify the occurrence and severity of bombings against civilian targets in diverse attack settings, and to establish corresponding blast injury profiles. Data was obtained from analysis of the Global Terrorism Database(GTD) and a meta-analysis of blast injury data derived from the PubMed database. Closed environment explosions were associated with significantly greater(p<0.05) mortality than in open spaces. The injury profiles were found to be influenced by attack setting, with higher rates of primary injury on trains and buses, and secondary injury in open space.展开更多
Background:Since the 1970 s,terrorist bombings in subways have been frequently occurring worldwide.To cope with this threat and to provide medical response countermeasures,we analyzed the characteristics of subway bom...Background:Since the 1970 s,terrorist bombings in subways have been frequently occurring worldwide.To cope with this threat and to provide medical response countermeasures,we analyzed the characteristics of subway bombing terrorist attacks and used the Haddon matrix to explore medical response strategies.Methods:First,we analyzed 111 subway bombings from 1970 to 2017 recorded in the Global Terrorism Database to provide a reference for the strategy exploration.Then,we convened an expert panel to use the Haddon matrix to explore the medical response strategies to subway bombings.Results:In recent decades,at least one bombing attack occurs every 3 years.Summarized by the Haddon matrix,the influencing factors of medical responses to conventional subway bombings include the adequacy of first-aid kits and the medical evacuation equipment,the traffic conditions affecting the evacuation,the continuity and stability of communication,as well as the factors exclusively attributed to dirty bomb attacks in subways,such as ionizing radiation protection capabilities,the structure of the radiation sickness treatment network based on the subway lines,and the disposal of radioactive sewage.These factors form the basis of the strategy discussion.Conclusions:Since subway bombings are long-term threats,it is necessary to have proper medical response preparation.Based on the Haddon matrix,we explored the medical response strategies for terrorist subway bombings,especially dirty bomb attacks.Haddon matrix can help policymakers systematically find the most important factors,which makes the preparations of the response more efficient.展开更多
In order to numerically evaluate the acoustic characteristics of liquid rocket engine thrust chambers by means of a computational fluid dynamics method, a mathematical model of an artificial constant-volume bomb is pr...In order to numerically evaluate the acoustic characteristics of liquid rocket engine thrust chambers by means of a computational fluid dynamics method, a mathematical model of an artificial constant-volume bomb is proposed in this paper. A localized pressure pulse with a very high amplitude can be imposed on specified regions in a combustion chamber, the numerical procedure of which is described. Pressure oscillations actuated by the released constant-volume bomb can then be analyzed via Fast Fourier Transformation（FFT）, and their modes can be identified according to the theoretical acoustic eigenfrequencies of the thrust chamber. The damping performances of the corresponding acoustic modes are evaluated by the half-power bandwidth method. The predicted acoustic characteristics and their damping for a special engine combustor agree well with the experimental data, validating the mathematical model and its numerical procedures. A small-thrust liquid rocket engine chamber is then analyzed by the present model. The First Longitudinal（1L） acoustic mode can be excited easily and is hard to be damped. The axial position of the central constantvolume bomb has little influence on the amplitude and damping capacity of the First Radial（1R） and 1L acoustic modes. Tangential acoustic modes can only be triggered by an off-centered constant-volume bomb, among which the First Tangential（1T） mode is the strongest and regarded as the most harmful one. The amplitude of the 1L acoustic mode is smaller, but its damping factor is larger, as a constant-volume bomb is imposed approaching the injector face. These results are contributed to evaluate the acoustic characteristics and their damping of the combustion chamber.展开更多
文摘The legacy of United States cluster munition use in Laos and Cambodia during the Second Indochina War is residual bomblets that unexpectedly detonate years later, killing and injuring children, farmers, and other civilians. Cluster munitions release dozens of smaller bomblets that rain deadly ammunition on troops, armored tanks, and vegetation, effectively striking broad sections of war zone landscapes in one launch. While many bomblets detonate immediately, others fail to detonate and can lie dormant on the ground for years. The primary objectives of this study were to document the long-term consequences and impacts of the US Air Force bombing of Laos and Cambodia during the Second Indochina War (1959 to 1973). The historical lessons learned by United States should be shared with Russia and Ukraine governments and military. These countries need to discontinue the use of cluster bombs to prevent additional people living along the Russia-Ukraine border from having to live and die with the consequences of unexploded ordnance, including cluster bombs, for the next century.
基金the National Natural Science Foundation of China(No.52371065)the Hubei Provincial Natural Science Foundation of China(No.2023AFB637).
文摘Magnesium(Mg)-based implants have been clinically proven to fulfill long-term service requirements,but their passive degradation periods remain to be uncontrollable.Herein,we developed a novel near infrared(NIR)-responsive coating on a Mg-Ag-Mn alloy with controllable biodegradation enhanced by air release.The coating exhibits a bi-layered structure,in which the outer layer consists of polycaprolactone(PCL)with the addition of nano-sized polypyrrole(PPy)particles for NIR response,whereas the inner layer is a porous ceramic film produced via plasma electrolytic oxidation(PEO).In particular,the porous structure of PEO film was proposed as a carrier for entrapped air to form the“air bomb”.Without NIR irradiation,the coating possesses a dense and homogeneous microstructure and exhibits excellent long-term durability in saline.Under the NIR irradiation,the PCL resin transforms from a rubbery state to a viscous state promoted by the photothermal action of PPy,while the thermal-expanded air in PEO film escapes from the PCL resin,resulting in macroscopic defects across the coating.This phenomenon leads to a change in the function of Mg alloy from"anti-corrosion"to"biodegradation".This work is expected to provide a new strategy for optimizing the service time of Mg-based implants.
基金supported by the National Natural Science Foundation of China(Grant No.42030410)the Laoshan Laboratory(Grant Nos.LSKJ202202404 and LSKJ202202403)+1 种基金the Startup Foundation for Introducing Tal-ent of NUIST,Jiangsu Innovation Research Group(Grant No.JSS-CTD202346)the Jiangsu Funding Program for Excellent Post-doctoral Talent(Grant No.2023ZB690).
文摘Bomb cyclones are rapidly deepening extratropical cyclones predominantly found in midlatitude regions.These extreme events are particularly frequent over the North Pacific(NP),posing significant societal and environmental risks.Currently,our understanding of the variability of bomb cyclones over the NP remains limited.This study analyzes the variations in multiple NP bomb cyclone characteristics from 1980 onward using four major reanalysis datasets.The results show a weakening trend of bomb cyclones since the beginning of the 21st century,which is characterized by significant reductions in maximum near-surface wind speeds,increases in minimum sea level pressure,and slower deepening rates.Further analysis reveals that the observed weakening trend of bomb cyclones is closely linked to a reduction in maximum 850 hPa Eady growth rate,driven primarily by reduced vertical wind shear within the 30°-45°N latitudinal band.Furthermore,our findings indicate that the Aleutian Low acts to modulate the meridional air temperature gradient over the midlatitude NP,which is corroborated by climate model outputs.This modulation provides a pathway for the Aleutian Low to affect low-level baroclinicity and thus bomb cyclone characteristics.These results have important implications for future projections of bomb cyclone activity over the NP,aiding in risk assessment and mitigating the impacts of these extreme events.
基金Supported by the Independent Scientific Research of Nanjing University of Science and Technology(2011YBXM110)~~
文摘The sequential dispersing results of aerial cluster bomb are discussed. The ballistic model and the mod- el for impact point distribution of bullets are established. The main factors influencing impact point distribution are analyzed by numerical simulation. And the feasibility of improving distribution effect through sequential dis- persing is validated. Sequential dispersion and optimized airdrop parameters can help to achieve better battle effec- tiveness.
文摘On a summer morning in Boqiang Village,tucked beneath the emerald mountains of Fanshi County,Shanxi Province,the Ultra Trail Mount Wutai2025 commenced with the sound of the starting pistol-an event that was much more than just a competition.As soon as the colorful smoke bombs lit up the sky,some2,000 runners from China and abroad set off to reach one of the country's most sacred Buddhist peaks.Over the past decade,this race has become a fixture on the global running calendar and a symbol of the growing popularity of endurance sports.
基金support of the Institute for Security Science and TechnologyThe Royal British Legion Centre for Blast Injury Studies at Imperial College LondonThe Institute of Shock Physics also acknowledges the support of Imperial College London
文摘An upsurge of terrorist activity has occurred in the past two decades. As part of this, explosive devices continue to be extensively deployed against civilians in wide-ranging environments. Bombings remain the leading worldwide cause of civilian fatalities due to terrorism. This demands an understanding of modern terrorist bombing trends to inform mitigation strategy. The objective of this study was to identify the occurrence and severity of bombings against civilian targets in diverse attack settings, and to establish corresponding blast injury profiles. Data was obtained from analysis of the Global Terrorism Database(GTD) and a meta-analysis of blast injury data derived from the PubMed database. Closed environment explosions were associated with significantly greater(p<0.05) mortality than in open spaces. The injury profiles were found to be influenced by attack setting, with higher rates of primary injury on trains and buses, and secondary injury in open space.
文摘Background:Since the 1970 s,terrorist bombings in subways have been frequently occurring worldwide.To cope with this threat and to provide medical response countermeasures,we analyzed the characteristics of subway bombing terrorist attacks and used the Haddon matrix to explore medical response strategies.Methods:First,we analyzed 111 subway bombings from 1970 to 2017 recorded in the Global Terrorism Database to provide a reference for the strategy exploration.Then,we convened an expert panel to use the Haddon matrix to explore the medical response strategies to subway bombings.Results:In recent decades,at least one bombing attack occurs every 3 years.Summarized by the Haddon matrix,the influencing factors of medical responses to conventional subway bombings include the adequacy of first-aid kits and the medical evacuation equipment,the traffic conditions affecting the evacuation,the continuity and stability of communication,as well as the factors exclusively attributed to dirty bomb attacks in subways,such as ionizing radiation protection capabilities,the structure of the radiation sickness treatment network based on the subway lines,and the disposal of radioactive sewage.These factors form the basis of the strategy discussion.Conclusions:Since subway bombings are long-term threats,it is necessary to have proper medical response preparation.Based on the Haddon matrix,we explored the medical response strategies for terrorist subway bombings,especially dirty bomb attacks.Haddon matrix can help policymakers systematically find the most important factors,which makes the preparations of the response more efficient.
基金Financial support from the National Natural Science Foundation of China (Nos.51676111 and 11628206)
文摘In order to numerically evaluate the acoustic characteristics of liquid rocket engine thrust chambers by means of a computational fluid dynamics method, a mathematical model of an artificial constant-volume bomb is proposed in this paper. A localized pressure pulse with a very high amplitude can be imposed on specified regions in a combustion chamber, the numerical procedure of which is described. Pressure oscillations actuated by the released constant-volume bomb can then be analyzed via Fast Fourier Transformation（FFT）, and their modes can be identified according to the theoretical acoustic eigenfrequencies of the thrust chamber. The damping performances of the corresponding acoustic modes are evaluated by the half-power bandwidth method. The predicted acoustic characteristics and their damping for a special engine combustor agree well with the experimental data, validating the mathematical model and its numerical procedures. A small-thrust liquid rocket engine chamber is then analyzed by the present model. The First Longitudinal（1L） acoustic mode can be excited easily and is hard to be damped. The axial position of the central constantvolume bomb has little influence on the amplitude and damping capacity of the First Radial（1R） and 1L acoustic modes. Tangential acoustic modes can only be triggered by an off-centered constant-volume bomb, among which the First Tangential（1T） mode is the strongest and regarded as the most harmful one. The amplitude of the 1L acoustic mode is smaller, but its damping factor is larger, as a constant-volume bomb is imposed approaching the injector face. These results are contributed to evaluate the acoustic characteristics and their damping of the combustion chamber.
