Introduction: Voluntary assault and injuries are acts that damage the physical and psychological integrity of a human being. WHO in its global report on violence and health estimates that in 2000, 1.6 million people w...Introduction: Voluntary assault and injuries are acts that damage the physical and psychological integrity of a human being. WHO in its global report on violence and health estimates that in 2000, 1.6 million people worldwide died as a result of self-harm, interpersonal or collective violence, resulting in an overall rate adjusted by age of 28.8 per 100,000 population. Because of the seriousness of this phenomenon and the heavy socio-economic and health consequences that they generate, it seemed important to us to undertake this study, which aimed to study the deliberate injuries in the emergency unite of the Gabriel Touré Teaching Hospital in Bamako. Material and methods: This was a descriptive and cross-sectional study with a prospective study from September 1st, 2016 to August 31st, 12 months, covering 295 patients, including any patient received for voluntary injury consultation with a workable medical record and/or a full investigation record with or without requisition. Our data were collected on individual survey cards and subsequently analyzed with Word, Excel, IBM SPSS Statistics 22 software. Results: The majority of victims of assault and bodily injury were male with 83.1%;with a sex ratio of 4.9, the 18 to 28 age group was the most concerned with 163 cases of the 295 cases in our study, 55.2%. The extremes were 6 and 100 years old with an ectype at 11.08. The most affected ethnic group was Bambara with 38.6% (n = 114) followed by Fulani with 15.6% (n = 46). Students were the most affected at 24.7% (n = 73), followed by traders at 10%. The victims coming from outside Bamako are the most predominant with 22.4% (n = 66) followed by those of commune IV of Bamako 15.6% (n = 46). In 92.2% of the cases the mechanism was direct with n = 272. Of the lesions recorded in our study, wounds came first with 53.2% of cases. Radiography was the most used imaging at 44.7% (n = 89) followed by computed tomography at 34.7% (n = 69). The hemoperitoneum objectified by abdominal ultrasound represented 29.3% (n = 12). Fractures embarrure associated with bruising-hemorrhagic bruises were the most predominant with 13.4% (n = 10) objectified by brain scan. Conclusion: We note that the phenomenon of violence has reached worrying proportions, especially among young adults, particularly among students and is observed in all so-cio-professional layers. The polymorphism of these injuries caused by the predominant use of knives must draw the attention of our authorities to take measures to reduce these aggressions.展开更多
Images provided by the author unless otherwise stated■This summer the first major U.S.solo exhibition by leading Taiwan Residents artist Chen Chieh-jen took place at Manhattan's Asia Society.The exhibition 'C...Images provided by the author unless otherwise stated■This summer the first major U.S.solo exhibition by leading Taiwan Residents artist Chen Chieh-jen took place at Manhattan's Asia Society.The exhibition 'Condensation' united five silent films that address a variety of social topics into a cohesive unit. The films reflect the mind of someone who came to artistic maturity during a rapidly changing political environment in Taiwan.展开更多
We investigate a class of non-integrable two-particle Calogero-Moser systems modulated by a power-law external potential.The local well-posedness of the Cauchy problem is established under the strict initial separatio...We investigate a class of non-integrable two-particle Calogero-Moser systems modulated by a power-law external potential.The local well-posedness of the Cauchy problem is established under the strict initial separation condition for the particles.For suitably prepared initial configurations,local solutions can be extended globally via energy conservation;conversely,negative energy conditions induce(in)finite-time blowup.The linear(in)stability of stationary solutions is analyzed,with their energy serving as a threshold.Numerical investigations employ a fourth-order Runge-Kutta scheme with adaptive step-size control.Simulations demonstrate that the trajectories either converge to steady states or exhibit blowup,depending on the power exponentαand initial conditions.Increasingαaccelerates the convergence rate and dampens oscillatory dynamics,promoting a transition from periodic behavior to static equilibrium.展开更多
Radiative cooling textiles with spectrally selective surfaces offer a promising energy-efficient approach for sub-ambient cooling of outdoor objects and individuals.However,the spectrally selective mid-infrared emissi...Radiative cooling textiles with spectrally selective surfaces offer a promising energy-efficient approach for sub-ambient cooling of outdoor objects and individuals.However,the spectrally selective mid-infrared emission of these textiles significantly hinders their efficient radiative heat exchange with self-heated objects,thereby posing a significant challenge to their versatile cooling applicability.Herein,we present a bicomponent blow spinning strategy for the production of scalable,ultra-flexible,and healable textiles featuring a tailored dual gradient in both chemical composition and fiber diameter.The gradient in the fiber diameter of this textile introduces a hierarchically porous structure across the sunlight incident area,thereby achieving a competitive solar reflectivity of 98.7%on its outer surface.Additionally,the gradient in the chemical composition of this textile contributes to the formation of Janus infrared-absorbing surfaces:The outer surface demonstrates a high mid-infrared emission,whereas the inner surface shows a broad infrared absorptivity,facilitating radiative heat exchange with underlying self-heated objects.Consequently,this textile demonstrates multi-scenario radiative cooling capabilities,enabling versatile outdoor cooling for unheated objects by 7.8℃ and self-heated objects by 13.6℃,compared to commercial sunshade fabrics.展开更多
The unfolding global financial crisis is arousing jitters about another round of heavy blows to the world economy, which may be intensified by the possible U.S. government takeover of Citigroup Inc. and Bank of Americ...The unfolding global financial crisis is arousing jitters about another round of heavy blows to the world economy, which may be intensified by the possible U.S. government takeover of Citigroup Inc. and Bank of America Corp. lg, Chief Economist of the Asia-Pacific region for Credit Suisse First Boston (Hong Kong ) Ltd., published an article in the Securities Market Weekly, warning about five other major crashes that might dampen global economic recovery. Edited excerpts follow.展开更多
There is a beautiful city in southwestern Germany,lying on the southern bank of the Rhine River,which has flowed quietly nearby since ancient times.The city was the hometown of Johannes Gutenberg,the inventor of moder...There is a beautiful city in southwestern Germany,lying on the southern bank of the Rhine River,which has flowed quietly nearby since ancient times.The city was the hometown of Johannes Gutenberg,the inventor of modern typography,as well as of an excellent Bundesliga soccer team.It features a combination of ancient flavor and modern fashion,with not only time-honored churches展开更多
OVER 2,000 years ago,the bronze craftsmen in today’s Datong City,Shanxi Province,had already mastered the superb skills of copper production.Datong bronze-making craft was included in China’s state-level intangible ...OVER 2,000 years ago,the bronze craftsmen in today’s Datong City,Shanxi Province,had already mastered the superb skills of copper production.Datong bronze-making craft was included in China’s state-level intangible cultural heritage list in 2014.The craftsmanship which has been passed down through the millennia still shines brightly today after countless hammer blows and engravings.展开更多
Although poly(lactic acid)(PLA)is a good environmentally-friendly bio-degradable polymer which is used to substitute traditional petrochemical-based polymer packaging films,the barrier properties of PLA films are stil...Although poly(lactic acid)(PLA)is a good environmentally-friendly bio-degradable polymer which is used to substitute traditional petrochemical-based polymer packaging films,the barrier properties of PLA films are still insufficient for high-barrier packaging applications.In this study,oxygen scavenger hydroxyl-terminated polybutadiene(HTPB)and cobalt salt catalyst were incorporated into the PLA/poly(butylene adipate-co-terephthalate)(PLA/PBAT),followed by melting extrusion and three-layer co-extrusion blown film process to prepare the composite films.The oxygen permeability coefficient of the composite film combined with 6 wt%oxygen scavenger and 0.4 wt%catalyst was decreased significantly from 377.00 cc·mil·m^(-2)·day^(-1)·0.1 MPa^(-1) to 0.98 cc·mil·m^(-2)·day^(-1)·0.1 MPa^(-1),showing a remarkable enhancement of 384.69 times compared with the PLA/PBAT composite film.Meanwhile,the degradation behavior of the composite film was also accelerated,exhibiting a mass loss of nearly 60%of the original mass after seven days of degradation in an alkaline environment,whereas PLA/PBAT composite film only showed a mass loss of 32%.This work has successfully prepared PLA/PBAT composite films with simultaneously improved oxygen barrier property and degradation behavior,which has great potential for high-demanding green chemistry packaging industries,including food,agricultural,and military packaging.展开更多
Blowing snow events in Antarctica play an important role in the climate system,affecting the mass balance of the ice sheet and the radiative effects of the atmosphere.Due to the harsh weather conditions in Antarctica,...Blowing snow events in Antarctica play an important role in the climate system,affecting the mass balance of the ice sheet and the radiative effects of the atmosphere.Due to the harsh weather conditions in Antarctica,ground-based detection data is deficient,making it difficult to accurately obtain both the frequency of blowing snow and the evolution of the height of the blowing snow layer.In this study,we introduce a new method based on the raw signal from the C12 ceilometer to separate clear-sky,cloud,snowfall,and blowing snow conditions within a height of 500 meters above the surface of Zhongshan Station.Research has shown that more than 80%of the blowing snow at Zhongshan Station is affected by cyclonic systems,and less than 20%of the blowing snow is affected by katabatic winds.Further,Antarctic blowing snow is closely related to snowfall.When there is heavy snowfall(even a blizzard),a smaller wind speed can lead to the formation of a deep blowing snow layer within an hour after snowfall.However,as time increases,the threshold wind speed required to generate blowing snow significantly increases,and the thickness of the blowing snow layer becomes shallower.展开更多
The top-bottom combined blowing converter mainly adopts the blowing method of top-blowing oxygen and bottom-blowing nitrogen.In the production process,there are some disadvantages,such as a significant temperature dif...The top-bottom combined blowing converter mainly adopts the blowing method of top-blowing oxygen and bottom-blowing nitrogen.In the production process,there are some disadvantages,such as a significant temperature difference between the top and bottom of the molten pool,inadequate gas permeability of bottom blowing,and low decarburization efficiency.Therefore,we propose a novel bottom-blowing gas doped oxygen process to enhance the smelting conditions in the converter.The 500 kg medium frequency induction furnace with top and bottom-blowing function was used to explore the influence of the proportion of bottom-blowing gas doped oxygen on the smelting effect in different smelting cycles.Subsequently,industrial experimental verification was carried out on a 60 t converter.The results of intermediate frequency furnace experiments demonstrate that the bottom-blowing gas doped oxygen process exhibits a superior heating rate and decarburization efficiency during the initial and final stages of blowing compared to pure N2 used for bottom-blowing.Simultaneously,the dephosphorization efficiency exhibited an initial increase followed by a subsequent decrease as the bottom-blowing oxygen content increased.The industrial test of 60 t converter validates the findings above.Moreover,when the oxygen content in bottom-blowing gas is 5%,the average blowing time reduces by 54 s,and the minimum endpoint carbon-oxygen equilibrium reaches 0.00219 under this condition.The results demonstrate that the appropriate amount of oxygen doped in bottom-blowing gas can effectively enhance the metallurgical conditions of the converter and improve production efficiency.展开更多
The turbulent characteristics of the top-blown Laval nozzle and the influence of pressure and Mach number were studied through numerical simulation.With 2.72%error between the results and the empirical formula,the res...The turbulent characteristics of the top-blown Laval nozzle and the influence of pressure and Mach number were studied through numerical simulation.With 2.72%error between the results and the empirical formula,the results are reliable.Nozzle fluid is influenced by pipe structure,causing pressure and density to drop as speed increases.Differences in pressure and velocity between the jet and surrounding gas lead to jet velocity attenuation,flow expansion,deflection,and eddy currents.The optimal top blowing pressure is 0.6 MPa,and the center velocity and width of the jet are 345 m/s and 0.124 m,respectively,at 20De(De is the nozzle exit diameter).It achieves a maximum jet velocity of 456 m/s.The optimal nozzle Mach number is 1.75,with a maximum jet velocity of 451 m/s.At 20D_(e),the jet center velocity is 338 m/s,with a width of 0.12 m.展开更多
In this paper,a class of semilinear parabolic equations with cross coupling of power and exponential functions and large initial values are studied.By constructing and solving ordinary differential equations,the upper...In this paper,a class of semilinear parabolic equations with cross coupling of power and exponential functions and large initial values are studied.By constructing and solving ordinary differential equations,the upper and lower bounds on the solution life span of the equations areobtained.展开更多
Under the background of the strategic goal of"double carbon,"the carbon reduction and consumption reduction of the iron and steel industry,especially in the ironmaking process,need to be further improved.The...Under the background of the strategic goal of"double carbon,"the carbon reduction and consumption reduction of the iron and steel industry,especially in the ironmaking process,need to be further improved.The raceway of tuyere provides the chemical environment,fuel and power source for blast furnace smelting.The research on the characteristics of its action mode and mechanism is of great significance to clarify the way of reducing carbon and consumption of blast furnace.In general,the formation mechanism,energy distribution,research progress,extended resource injection and directional regulation are studied and expounded.The research results of various scholars on the characteristics of the raceway show that the raceway is a complex process including multiphase turbulent flow,heat,momentum,mass and homogeneous and heterogeneous chemical reactions.With the development of multi-source fuel injection technology,the complexity of problem research is more obvious.Therefore,the collection of multi-factor,multi-directional and multi-process characteristic information in the raceway can provide guarantee for the stability,smooth operation,high yield,carbon reduction and consumption reduction of blast furnace and provide new ideas for the green and low-carbon development of iron and steel industry.展开更多
The primary objective of this paper is to investigate the well-posedness theories associated with the discrete nonlinear Schrodinger and Klein-Gordon equations.These theories encompass both local and global well-posed...The primary objective of this paper is to investigate the well-posedness theories associated with the discrete nonlinear Schrodinger and Klein-Gordon equations.These theories encompass both local and global well-posedness,as well as the existence of blowing-up solutions for large and irregular initial data.The main results presented in this paper can be summarized as follows:(1)Discrete Nonlinear Schrodinger Equation:Global well-posedness in l^(p) spaces for all1≤p≤∞,regardless of whether it is in the defocusing or focusing cases.(2)Discrete Klein-Gordon Equation:Local well-posedness in l^(p) spaces for all 1≤p≤∞.Furthermore,in the defocusing case,we establish global well-posedness in l^(p) spaces for any2≤p≤2σ+2(σ>0).In contrast,in the focusing case,we show that solutions with negative energy blow up within a finite time.These conclusions reveal the distinct dynamic behaviors exhibited by the solutions of the equations in discrete settings compared to their continuous setting.Additionally,they illuminate the significant role that discretization plays in preventing ill-posedness,and collapse for the nonlinear Schrodinger equation.展开更多
In this article,we study the water wave problem with critical growth.We mainly concern with the blowup and asymptotic estimates of the global solution.First,we prove the blow up and decay estimates of the solution wit...In this article,we study the water wave problem with critical growth.We mainly concern with the blowup and asymptotic estimates of the global solution.First,we prove the blow up and decay estimates of the solution with low-energy initial value.Next,we prove the regularity of the global solution with low-energy initial value.In the last part,we study the concentration phenomenon of the global solution no matter with low energy or not by the method of concentration compactness principle.展开更多
Stall flutter poses great challenges to flight safety.To alleviate this problem,a steady blowing control considering the perturbation and wake-induced vibration at a large angle of attack is developed in this paper,wh...Stall flutter poses great challenges to flight safety.To alleviate this problem,a steady blowing control considering the perturbation and wake-induced vibration at a large angle of attack is developed in this paper,where two blowings are configured on upper and lower tail surfaces to suppress the stall flutter.The stall flutter with one-degree-of-freedom is first evaluated by numerical simulation.The equation of motion for stall flutter is solved by the Newmark-β method.Then,the stall flutter responses for five blowing speeds,i.e.,0,4,12,20,and 28 m/s under the airspeed range of 3–9 m/s,are studied in detail.The stall flutter suppression mechanism can be summarized as follows:a large blowing speed can inject energy into the boundary layer and enhance the high-pressure zone,which delays the flow separation on the suction surface.In this way,the formation of the leading-edge separation vortex is suppressed.Thus,the dynamic stall vortex is weakened and accelerates shedding.In addition,the driving moment is reduced,which leads to a decrement in the stall flutter amplitude.When the blowing speed is 28 m/s(stall flutter amplitude=0.1357 rad),compared with uncontrolled case(stall flutter amplitude=0.6002 rad),the amplitude can decrease by 77.39%,which demonstrates the effectiveness of the proposed steady blowing based active control strategy.展开更多
Sea ice and snow are the most sensitive and important crucial components of the global climate system,affecting the global climate by modulating the energy exchange between the ocean and the atmosphere.The sea near Zh...Sea ice and snow are the most sensitive and important crucial components of the global climate system,affecting the global climate by modulating the energy exchange between the ocean and the atmosphere.The sea near Zhongshan Station in Antarctica is covered by landfast sea ice,with snow depth influenced by both thermal factors and wind.This region frequently experiences katabatic winds and cyclones from the westerlies,leading to frequent snow blowing events that redistribute the snow and affects its depth,subsequently impacting the thermodynamic growth of sea ice.This study utilized the one-dimensional thermodynamic model ICEPACK to simulate landfast sea ice thickness and snow depth near Zhongshan Station in 2016.Two parameterization schemes for snow blowing,the Bulk scheme,and the ITDrdg(ITD/ridges)scheme are evaluated for their impact on snow depth.The results show that simulations using snow blowing schemes more closely align with observed results,with the ITDrdg scheme providing more accurate simulations,evidenced by root mean square errors of less than 10 cm for both snow depth and sea ice thickness.Snow blowing also impacts the thermodynamic growth of sea ice,particularly bottom growth.The sea ice bottom increases by 9.0 cm using the ITDrdg scheme compared to simulations without the snow blowing,accounting for 12.5%of total sea ice bottom growth.Furthermore,snow blowing process also influences snow ice formation,highlighting its primary role in affecting snow depth.Continued field observations of snow blowing are necessary to evaluate and improve parameterization schemes.展开更多
文摘Introduction: Voluntary assault and injuries are acts that damage the physical and psychological integrity of a human being. WHO in its global report on violence and health estimates that in 2000, 1.6 million people worldwide died as a result of self-harm, interpersonal or collective violence, resulting in an overall rate adjusted by age of 28.8 per 100,000 population. Because of the seriousness of this phenomenon and the heavy socio-economic and health consequences that they generate, it seemed important to us to undertake this study, which aimed to study the deliberate injuries in the emergency unite of the Gabriel Touré Teaching Hospital in Bamako. Material and methods: This was a descriptive and cross-sectional study with a prospective study from September 1st, 2016 to August 31st, 12 months, covering 295 patients, including any patient received for voluntary injury consultation with a workable medical record and/or a full investigation record with or without requisition. Our data were collected on individual survey cards and subsequently analyzed with Word, Excel, IBM SPSS Statistics 22 software. Results: The majority of victims of assault and bodily injury were male with 83.1%;with a sex ratio of 4.9, the 18 to 28 age group was the most concerned with 163 cases of the 295 cases in our study, 55.2%. The extremes were 6 and 100 years old with an ectype at 11.08. The most affected ethnic group was Bambara with 38.6% (n = 114) followed by Fulani with 15.6% (n = 46). Students were the most affected at 24.7% (n = 73), followed by traders at 10%. The victims coming from outside Bamako are the most predominant with 22.4% (n = 66) followed by those of commune IV of Bamako 15.6% (n = 46). In 92.2% of the cases the mechanism was direct with n = 272. Of the lesions recorded in our study, wounds came first with 53.2% of cases. Radiography was the most used imaging at 44.7% (n = 89) followed by computed tomography at 34.7% (n = 69). The hemoperitoneum objectified by abdominal ultrasound represented 29.3% (n = 12). Fractures embarrure associated with bruising-hemorrhagic bruises were the most predominant with 13.4% (n = 10) objectified by brain scan. Conclusion: We note that the phenomenon of violence has reached worrying proportions, especially among young adults, particularly among students and is observed in all so-cio-professional layers. The polymorphism of these injuries caused by the predominant use of knives must draw the attention of our authorities to take measures to reduce these aggressions.
文摘Images provided by the author unless otherwise stated■This summer the first major U.S.solo exhibition by leading Taiwan Residents artist Chen Chieh-jen took place at Manhattan's Asia Society.The exhibition 'Condensation' united five silent films that address a variety of social topics into a cohesive unit. The films reflect the mind of someone who came to artistic maturity during a rapidly changing political environment in Taiwan.
基金Supported by National Natural Science Foundation of China(12201118)Guangdong Basic and Applied Basic Research Foundation(2023A1515010706)。
文摘We investigate a class of non-integrable two-particle Calogero-Moser systems modulated by a power-law external potential.The local well-posedness of the Cauchy problem is established under the strict initial separation condition for the particles.For suitably prepared initial configurations,local solutions can be extended globally via energy conservation;conversely,negative energy conditions induce(in)finite-time blowup.The linear(in)stability of stationary solutions is analyzed,with their energy serving as a threshold.Numerical investigations employ a fourth-order Runge-Kutta scheme with adaptive step-size control.Simulations demonstrate that the trajectories either converge to steady states or exhibit blowup,depending on the power exponentαand initial conditions.Increasingαaccelerates the convergence rate and dampens oscillatory dynamics,promoting a transition from periodic behavior to static equilibrium.
基金financial support from the National Natural Science Foundation of China(Grant No.52273067,52233006)the Fundamental Research Funds for the Central Universities(Grant No.2232023A-03)+3 种基金the Shuguang Program of Shanghai Education Development Foundation and Shanghai Municipal Education Commission(Grant No.23SG29)the Natural Science Foundation of Shanghai(Grant No.24ZR1402400)the Shanghai Scientific and Technological Innovation Project(Grant No.24520713000)Innovation Program of Shanghai Municipal Education Commission(Grant No.2021-01-07-00-03-E00108).
文摘Radiative cooling textiles with spectrally selective surfaces offer a promising energy-efficient approach for sub-ambient cooling of outdoor objects and individuals.However,the spectrally selective mid-infrared emission of these textiles significantly hinders their efficient radiative heat exchange with self-heated objects,thereby posing a significant challenge to their versatile cooling applicability.Herein,we present a bicomponent blow spinning strategy for the production of scalable,ultra-flexible,and healable textiles featuring a tailored dual gradient in both chemical composition and fiber diameter.The gradient in the fiber diameter of this textile introduces a hierarchically porous structure across the sunlight incident area,thereby achieving a competitive solar reflectivity of 98.7%on its outer surface.Additionally,the gradient in the chemical composition of this textile contributes to the formation of Janus infrared-absorbing surfaces:The outer surface demonstrates a high mid-infrared emission,whereas the inner surface shows a broad infrared absorptivity,facilitating radiative heat exchange with underlying self-heated objects.Consequently,this textile demonstrates multi-scenario radiative cooling capabilities,enabling versatile outdoor cooling for unheated objects by 7.8℃ and self-heated objects by 13.6℃,compared to commercial sunshade fabrics.
文摘The unfolding global financial crisis is arousing jitters about another round of heavy blows to the world economy, which may be intensified by the possible U.S. government takeover of Citigroup Inc. and Bank of America Corp. lg, Chief Economist of the Asia-Pacific region for Credit Suisse First Boston (Hong Kong ) Ltd., published an article in the Securities Market Weekly, warning about five other major crashes that might dampen global economic recovery. Edited excerpts follow.
文摘There is a beautiful city in southwestern Germany,lying on the southern bank of the Rhine River,which has flowed quietly nearby since ancient times.The city was the hometown of Johannes Gutenberg,the inventor of modern typography,as well as of an excellent Bundesliga soccer team.It features a combination of ancient flavor and modern fashion,with not only time-honored churches
文摘OVER 2,000 years ago,the bronze craftsmen in today’s Datong City,Shanxi Province,had already mastered the superb skills of copper production.Datong bronze-making craft was included in China’s state-level intangible cultural heritage list in 2014.The craftsmanship which has been passed down through the millennia still shines brightly today after countless hammer blows and engravings.
基金financial support of this work by the National Natural Science Foundation of China(Nos.22378332,52003219)the Open Fund of Zhejiang Key Laboratory of Flexible Electronics(No.2022FE008)+1 种基金the Natural Science Foundation of Ningbo(NO.2022J058)Ministry of Industry and Information Technology high quality development project(TC220A04A-206).
文摘Although poly(lactic acid)(PLA)is a good environmentally-friendly bio-degradable polymer which is used to substitute traditional petrochemical-based polymer packaging films,the barrier properties of PLA films are still insufficient for high-barrier packaging applications.In this study,oxygen scavenger hydroxyl-terminated polybutadiene(HTPB)and cobalt salt catalyst were incorporated into the PLA/poly(butylene adipate-co-terephthalate)(PLA/PBAT),followed by melting extrusion and three-layer co-extrusion blown film process to prepare the composite films.The oxygen permeability coefficient of the composite film combined with 6 wt%oxygen scavenger and 0.4 wt%catalyst was decreased significantly from 377.00 cc·mil·m^(-2)·day^(-1)·0.1 MPa^(-1) to 0.98 cc·mil·m^(-2)·day^(-1)·0.1 MPa^(-1),showing a remarkable enhancement of 384.69 times compared with the PLA/PBAT composite film.Meanwhile,the degradation behavior of the composite film was also accelerated,exhibiting a mass loss of nearly 60%of the original mass after seven days of degradation in an alkaline environment,whereas PLA/PBAT composite film only showed a mass loss of 32%.This work has successfully prepared PLA/PBAT composite films with simultaneously improved oxygen barrier property and degradation behavior,which has great potential for high-demanding green chemistry packaging industries,including food,agricultural,and military packaging.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFC2802501)the National Natural Science Foundation of China(Grant Nos.41875025,62105367,42175154,42305084)+1 种基金the Hunan Provincial Natural Science Foundation of China(Grant Nos.2021JJ10047,2020JJ4662)the Research Project of National University of Defense Technology(Grant No.202401-YJRC-XX-030)。
文摘Blowing snow events in Antarctica play an important role in the climate system,affecting the mass balance of the ice sheet and the radiative effects of the atmosphere.Due to the harsh weather conditions in Antarctica,ground-based detection data is deficient,making it difficult to accurately obtain both the frequency of blowing snow and the evolution of the height of the blowing snow layer.In this study,we introduce a new method based on the raw signal from the C12 ceilometer to separate clear-sky,cloud,snowfall,and blowing snow conditions within a height of 500 meters above the surface of Zhongshan Station.Research has shown that more than 80%of the blowing snow at Zhongshan Station is affected by cyclonic systems,and less than 20%of the blowing snow is affected by katabatic winds.Further,Antarctic blowing snow is closely related to snowfall.When there is heavy snowfall(even a blizzard),a smaller wind speed can lead to the formation of a deep blowing snow layer within an hour after snowfall.However,as time increases,the threshold wind speed required to generate blowing snow significantly increases,and the thickness of the blowing snow layer becomes shallower.
基金supported by the National Natural Science Foundation of China(No.U21A20317)the National Key Research and Development Program of China(No.2017YFB0304201).
文摘The top-bottom combined blowing converter mainly adopts the blowing method of top-blowing oxygen and bottom-blowing nitrogen.In the production process,there are some disadvantages,such as a significant temperature difference between the top and bottom of the molten pool,inadequate gas permeability of bottom blowing,and low decarburization efficiency.Therefore,we propose a novel bottom-blowing gas doped oxygen process to enhance the smelting conditions in the converter.The 500 kg medium frequency induction furnace with top and bottom-blowing function was used to explore the influence of the proportion of bottom-blowing gas doped oxygen on the smelting effect in different smelting cycles.Subsequently,industrial experimental verification was carried out on a 60 t converter.The results of intermediate frequency furnace experiments demonstrate that the bottom-blowing gas doped oxygen process exhibits a superior heating rate and decarburization efficiency during the initial and final stages of blowing compared to pure N2 used for bottom-blowing.Simultaneously,the dephosphorization efficiency exhibited an initial increase followed by a subsequent decrease as the bottom-blowing oxygen content increased.The industrial test of 60 t converter validates the findings above.Moreover,when the oxygen content in bottom-blowing gas is 5%,the average blowing time reduces by 54 s,and the minimum endpoint carbon-oxygen equilibrium reaches 0.00219 under this condition.The results demonstrate that the appropriate amount of oxygen doped in bottom-blowing gas can effectively enhance the metallurgical conditions of the converter and improve production efficiency.
基金supported by the National Key Research and Development Project of China(No.2022YFC3902001)the National Natural Science Foundation of China(No.52004340)the Guangxi Innovation-driven Development Project,China(Nos.Gui 2021AA12006 and 2021AB26024)。
文摘The turbulent characteristics of the top-blown Laval nozzle and the influence of pressure and Mach number were studied through numerical simulation.With 2.72%error between the results and the empirical formula,the results are reliable.Nozzle fluid is influenced by pipe structure,causing pressure and density to drop as speed increases.Differences in pressure and velocity between the jet and surrounding gas lead to jet velocity attenuation,flow expansion,deflection,and eddy currents.The optimal top blowing pressure is 0.6 MPa,and the center velocity and width of the jet are 345 m/s and 0.124 m,respectively,at 20De(De is the nozzle exit diameter).It achieves a maximum jet velocity of 456 m/s.The optimal nozzle Mach number is 1.75,with a maximum jet velocity of 451 m/s.At 20D_(e),the jet center velocity is 338 m/s,with a width of 0.12 m.
基金Supported by Key Project Funding for Shaanxi Higher Education Teaching Reform Research (23BZ078)Shaanxi Provincial Education Science Planning Project (SGH24Y2782)+4 种基金Shaanxi Provincial Social Science Foundation Program(2024D008)Key Projects of the Second Huang Yanpei Vocational Education Thought Research Planning Project (ZJS2024ZN026)Shaanxi Higher Education Society Key Projects(XGHZ2301)2024 Annual Planning Project of the China Association for Non-Government Education (School Development Category)(CANFZG24095)the Youth Innovation Team of Shaanxi Universities。
文摘In this paper,a class of semilinear parabolic equations with cross coupling of power and exponential functions and large initial values are studied.By constructing and solving ordinary differential equations,the upper and lower bounds on the solution life span of the equations areobtained.
基金financially supported by the Major Science and Technology-Special Plan“Unveiling and Leading”Project of Shanxi Province(No.202201050201011)National Natural Science Foundation of China(No.52274316)+4 种基金China Baowu Low-Carbon Metallurgy Innovation Foundation(No.BWLCF202116)National Key R&D Program of China(No.2022YFE0208100)Major Science and Technology Project of Xinjiang(No.2022A01003)Major Science and Technology Projects of Anhui Province(No.202210700037)Special Funding for Science and Technology of China Minmetals Corporation(No.2021ZXD01).
文摘Under the background of the strategic goal of"double carbon,"the carbon reduction and consumption reduction of the iron and steel industry,especially in the ironmaking process,need to be further improved.The raceway of tuyere provides the chemical environment,fuel and power source for blast furnace smelting.The research on the characteristics of its action mode and mechanism is of great significance to clarify the way of reducing carbon and consumption of blast furnace.In general,the formation mechanism,energy distribution,research progress,extended resource injection and directional regulation are studied and expounded.The research results of various scholars on the characteristics of the raceway show that the raceway is a complex process including multiphase turbulent flow,heat,momentum,mass and homogeneous and heterogeneous chemical reactions.With the development of multi-source fuel injection technology,the complexity of problem research is more obvious.Therefore,the collection of multi-factor,multi-directional and multi-process characteristic information in the raceway can provide guarantee for the stability,smooth operation,high yield,carbon reduction and consumption reduction of blast furnace and provide new ideas for the green and low-carbon development of iron and steel industry.
基金in part supported by the NSFC(12171356,12494544)supported by the National Key R&D Program of China(2020 YFA0713300)+1 种基金the NSFC(12531006)the Nankai Zhide Foundation。
文摘The primary objective of this paper is to investigate the well-posedness theories associated with the discrete nonlinear Schrodinger and Klein-Gordon equations.These theories encompass both local and global well-posedness,as well as the existence of blowing-up solutions for large and irregular initial data.The main results presented in this paper can be summarized as follows:(1)Discrete Nonlinear Schrodinger Equation:Global well-posedness in l^(p) spaces for all1≤p≤∞,regardless of whether it is in the defocusing or focusing cases.(2)Discrete Klein-Gordon Equation:Local well-posedness in l^(p) spaces for all 1≤p≤∞.Furthermore,in the defocusing case,we establish global well-posedness in l^(p) spaces for any2≤p≤2σ+2(σ>0).In contrast,in the focusing case,we show that solutions with negative energy blow up within a finite time.These conclusions reveal the distinct dynamic behaviors exhibited by the solutions of the equations in discrete settings compared to their continuous setting.Additionally,they illuminate the significant role that discretization plays in preventing ill-posedness,and collapse for the nonlinear Schrodinger equation.
基金supported by the NSFC(12071391,12231016)the Guangdong Basic and Applied Basic Research Foundation(2022A1515010860)。
文摘In this article,we study the water wave problem with critical growth.We mainly concern with the blowup and asymptotic estimates of the global solution.First,we prove the blow up and decay estimates of the solution with low-energy initial value.Next,we prove the regularity of the global solution with low-energy initial value.In the last part,we study the concentration phenomenon of the global solution no matter with low energy or not by the method of concentration compactness principle.
基金co-supported by the National Natural Science Foundation of China(Nos.52472394,52425211,52201327,52272360)。
文摘Stall flutter poses great challenges to flight safety.To alleviate this problem,a steady blowing control considering the perturbation and wake-induced vibration at a large angle of attack is developed in this paper,where two blowings are configured on upper and lower tail surfaces to suppress the stall flutter.The stall flutter with one-degree-of-freedom is first evaluated by numerical simulation.The equation of motion for stall flutter is solved by the Newmark-β method.Then,the stall flutter responses for five blowing speeds,i.e.,0,4,12,20,and 28 m/s under the airspeed range of 3–9 m/s,are studied in detail.The stall flutter suppression mechanism can be summarized as follows:a large blowing speed can inject energy into the boundary layer and enhance the high-pressure zone,which delays the flow separation on the suction surface.In this way,the formation of the leading-edge separation vortex is suppressed.Thus,the dynamic stall vortex is weakened and accelerates shedding.In addition,the driving moment is reduced,which leads to a decrement in the stall flutter amplitude.When the blowing speed is 28 m/s(stall flutter amplitude=0.1357 rad),compared with uncontrolled case(stall flutter amplitude=0.6002 rad),the amplitude can decrease by 77.39%,which demonstrates the effectiveness of the proposed steady blowing based active control strategy.
基金The National Natural Science Foundation of China under contract Nos 42306255 and 41976217the National Key R&D Program of China under contract No.2018YFA0605903。
文摘Sea ice and snow are the most sensitive and important crucial components of the global climate system,affecting the global climate by modulating the energy exchange between the ocean and the atmosphere.The sea near Zhongshan Station in Antarctica is covered by landfast sea ice,with snow depth influenced by both thermal factors and wind.This region frequently experiences katabatic winds and cyclones from the westerlies,leading to frequent snow blowing events that redistribute the snow and affects its depth,subsequently impacting the thermodynamic growth of sea ice.This study utilized the one-dimensional thermodynamic model ICEPACK to simulate landfast sea ice thickness and snow depth near Zhongshan Station in 2016.Two parameterization schemes for snow blowing,the Bulk scheme,and the ITDrdg(ITD/ridges)scheme are evaluated for their impact on snow depth.The results show that simulations using snow blowing schemes more closely align with observed results,with the ITDrdg scheme providing more accurate simulations,evidenced by root mean square errors of less than 10 cm for both snow depth and sea ice thickness.Snow blowing also impacts the thermodynamic growth of sea ice,particularly bottom growth.The sea ice bottom increases by 9.0 cm using the ITDrdg scheme compared to simulations without the snow blowing,accounting for 12.5%of total sea ice bottom growth.Furthermore,snow blowing process also influences snow ice formation,highlighting its primary role in affecting snow depth.Continued field observations of snow blowing are necessary to evaluate and improve parameterization schemes.
