BACKGROUND Myocardial infarction,particularly ST-segment elevation myocardial infarction(STEMI),is a key global mortality cause.Our study investigated predictors of mortality in 96 STEMI patients undergoing primary pe...BACKGROUND Myocardial infarction,particularly ST-segment elevation myocardial infarction(STEMI),is a key global mortality cause.Our study investigated predictors of mortality in 96 STEMI patients undergoing primary percutaneous coronary intervention at Erbil Cardiac Center.Multiple factors were identified influencing in-hospital mortality.Significantly,time from symptom onset to hospital arrival emerged as a decisive factor.Consequently,our study hypothesis is:"Reducing time from symptom onset to hospital arrival significantly improves STEMI prognosis."AIM To determine the key factors influencing mortality rates in STEMI patients.METHODS We studied 96 consecutive STEMI patients undergoing primary percutaneous coronary intervention(PPCI)at the Erbil Cardiac Center.Their clinical histories were compiled,and coronary evaluations were performed via angiography on admission.Data included comorbid conditions,onset of cardiogenic shock,complications during PPCI,and more.Post-discharge,one-month follow-up assessments were completed.Statistical significance was set at P<0.05.RESULTS Our results unearthed several significant findings.The in-hospital and 30-d mortality rates among the 96 STEMI patients were 11.2%and 2.3%respectively.On the investigation of independent predictors of in-hospital mortality,we identified atypical presentation,onset of cardiogenic shock,presence of chronic kidney disease,Thrombolysis In Myocardial Infarction grades 0/1/2,triple vessel disease,ventricular tachycardia/ventricular fibrillation,coronary dissection,and the no-reflow phenomenon.Specifically,the recorded average time from symptom onset to hospital arrival amongst patients who did not survive was significantly longer(6.92±3.86 h)compared to those who survived(3.61±1.67 h),P<0.001.These findings underscore the critical role of timely intervention in improving the survival outcomes of STEMI patients.CONCLUSION Our results affirm that early hospital arrival after symptom onset significantly improves survival rates in STEMI patients,highlighting the critical need for prompt intervention.展开更多
1.This study is one of The Applied Economic Institutes Linkages Project(AERIL)which is funded by theCanadian International Development Agency(CIDA)and jiontly managed by The Conference Board of Canada(CBOC)and the Int...1.This study is one of The Applied Economic Institutes Linkages Project(AERIL)which is funded by theCanadian International Development Agency(CIDA)and jiontly managed by The Conference Board of Canada(CBOC)and the International Trade Research Institute in China.It is jointly implemented by the Institute ofEconomic Research of the Chinese State Planning Commission and the North—South Institute of Canada。展开更多
The tropical cyclone that lands or passes through Guangxi coast is a serious natural disaster, which brings about strong winds, heavy rains, storm surges and other disasters causing severe damage of property or casual...The tropical cyclone that lands or passes through Guangxi coast is a serious natural disaster, which brings about strong winds, heavy rains, storm surges and other disasters causing severe damage of property or casualties in the coastal region every year. By counting and analyzing the tropical cyclones affecting Guangxi coast from 1950 to 2012, we find that the annual number of tropical cyclones changes significantly, and the maximum value can be up to 9, whereas the minimum value is 0 in some year. The regularity of seasonal distribution of tropical cyclones is obvious, and the peak period is in July, August and September every year, followed by June and October. Most of tropical cyclones come from the east of Philippines. After entering the South China Sea and passing through Hainan province and Leizhou Peninsula, they landed on Guangxi coast once again and caused the mean of peak surge reaching 111.2 cm, which is 2.6 times of non-landing typhoon. The formation of storm surge disaster is directly related to the severe typhoon weather systems, diurnal spring tide and discharge of river flood. Severe typhoons generate huge waves and rainfall, which lead to the rise of water level at the estuary, and would result in significant increasing water when stacking up with the storm surge, and cause huge tidal disaster.展开更多
Using linear regression and correlation analysis method,the variation trend characteristics of average temperature,sunshine,precipitation and the phenology of five kinds of animals(Barn Swallows,Frogs,Cryptotympana at...Using linear regression and correlation analysis method,the variation trend characteristics of average temperature,sunshine,precipitation and the phenology of five kinds of animals(Barn Swallows,Frogs,Cryptotympana atra,Crickets,Indian Cuckoo) in Huimin County during 1980-2008 were analyzed.On this basis,the relationship between the phenological phases of various animals and monthly temperature,sunshine and precipitation was analyzed.And the reasons that the phenological phases of various animals adapted to the climatic factors were also discussed.展开更多
In this paper,an efficien formulation based on the Lagrangian method is presented to investigate the contact–impact problems of f exible multi-body systems.Generally,the penalty method and the Hertz contact law are t...In this paper,an efficien formulation based on the Lagrangian method is presented to investigate the contact–impact problems of f exible multi-body systems.Generally,the penalty method and the Hertz contact law are the most commonly used methods in engineering applications.However,these methods are highly dependent on various non-physical parameters,which have great effects on the simulation results.Moreover,a tremendous number of degrees of freedom in the contact–impact problems will influenc thenumericalefficien ysignificantl.Withtheconsideration of these two problems,a formulation combining the component mode synthesis method and the Lagrangian method is presented to investigate the contact–impact problems in fl xible multi-body system numerically.Meanwhile,the finit element meshing laws of the contact bodies will be studied preliminarily.A numerical example with experimental verificatio will certify the reliability of the presented formulationincontact–impactanalysis.Furthermore,aseries of numerical investigations explain how great the influenc of the finit element meshing has on the simulation results.Finally the limitations of the element size in different regions are summarized to satisfy both the accuracy and efficien y.展开更多
The Loess Plateau of China has experienced a lengthy drought and severe soil erosion.Changes in precipitation and land use largely determine the dynamics of runoff and sediment yield in this region. Trend and mutation...The Loess Plateau of China has experienced a lengthy drought and severe soil erosion.Changes in precipitation and land use largely determine the dynamics of runoff and sediment yield in this region. Trend and mutation analyses were performed on hydrological data(1981–2012) from the Yanwachuan watershed in the Loess Plateau Gully Region to study the evolution characteristics of runoff and sediment yield. A time-series contrasting method also was used to evaluate the effects of precipitation and soil and water conservation(SWC) on runoff and sediment yield. Annual sediment yield declined markedly from 1981 to 2012 although there was no significant change in annual precipitation and annual runoff. Change points of annual runoff and annual sediment yield occurred in 1996 and 1997,respectively. Compared with that in the baseline period(1981–1996), annual runoff and annual sediment yield in the change period(1997–2012)decreased by 17.0% and 76.0%, respectively, but annual precipitation increased by 6.3%. Runoff decreased in the flood season and normal season, but increased in the dry season, while sediment yield significantly declined in the whole study period. The SWC measures contributed significantly to the reduction of annual runoff(137.9%) and annual sediment yield(135%) and were more important than precipitation. Biological measures(forestland and grassland) accounted for 61.04% of total runoff reduction, while engineering measures(terraces and dams) accounted for 102.84% of total sediment yield reduction. Furthermore, SWC measures had positive ecological effects. This study provides a scientific basis for soil erosion control on the Loess Plateau.展开更多
[Objective] The research aimed to study the influence of facility agriculture development on the climate variation in Weifang. [Method] Shouguang was selected as the representative station of greenhouse shed planting ...[Objective] The research aimed to study the influence of facility agriculture development on the climate variation in Weifang. [Method] Shouguang was selected as the representative station of greenhouse shed planting zone. By using the precipitation, temperature and relative humidity, etc. in Weifang City during 1961-2010, the climatic variation situations in the whole city and the greenhouse shed planting zone were analyzed. The variation trend and evolution characteristics of climate in the different seasons before and after the facility agriculture plantation were contrasted and analyzed. [Result] The annual rainfall and relative humidity presented the declining trend in the whole city in recent 50 years. The annual average, maximum and minimum temperatures all presented the rising trend. Since the large-scale plantation of greenhouse shed, the declining range of annual rainfall in the greenhouse shed planting zone was lower than that in the whole city, and the declining range of relative humidity was obviously higher than that in the whole city. The rising ranges of annual average, maximum and minimum temperatures were higher than that in the whole city. [Conclusion] The research provided the theory basis for the development of facility agriculture.展开更多
Agricultural and rural economic policy system is one main driving force for the evolvement of agricultural Non-Point Source (NPS) pollution. In this paper, the main policies that influence agricultural NPS pollution...Agricultural and rural economic policy system is one main driving force for the evolvement of agricultural Non-Point Source (NPS) pollution. In this paper, the main policies that influence agricultural NPS pollution are chosen, and a method to evaluate the impacts of agricultural and rural economic policy system on agricultural NPS pollution is brought forward. According to this, the questions about how and to what degree the policy system influence on agricultural NPS pollution are discussed.展开更多
Database applications are becoming increasingly popular, mainly due to the advanced data management facilities that the underlying database management system offers compared against traditional legacy software applica...Database applications are becoming increasingly popular, mainly due to the advanced data management facilities that the underlying database management system offers compared against traditional legacy software applications. The interaction, however, of such applications with the database system introduces a number of issues, among which, this paper addresses the impact analysis of the changes performed at the database schema level. Our motivation is to provide the software engineers of database applications with automated methods that facilitate major maintenance tasks, such as source code corrections and regression testing, which should be triggered by the occurrence of such changes. The presented impact analysis is thus two-folded: the impact is analysed in terms of both the affected source code statements and the affected test suites concerning the testing of these applications. To achieve the former objective, a program slicing technique is employed, which is based on an extended version of the program dependency graph. The latter objective requires the analysis of test suites generated for database applications, which is accomplished by employing testing techniques tailored for this type of applications. Utilising both the slicing and the testing techniques enhances program comprehension of database applications, while also supporting the development of a number of practical metrics regarding their maintainability against schema changes. To evaluate the feasibility and effectiveness of the presented techniques and metrics, a software tool, called DATA, has been implemented. The experimental results from its usage on the TPC-C case study are reported and analysed.展开更多
Based on linearized 2-D Navier-Stokes equation, a Laplacetransform-boundary element coupling method for viscousfluid-structure impact analysis is proposed. Under assumption ofincompressibility for the fluid, the corre...Based on linearized 2-D Navier-Stokes equation, a Laplacetransform-boundary element coupling method for viscousfluid-structure impact analysis is proposed. Under assumption ofincompressibility for the fluid, the corresponding equivalentboundary integral equation in terms of the potential function andstream function is first established by Lamb's transform in theLaplace transform domain.展开更多
Britton Chance was a pioneer in many scientifc fields such as enzymatic reaction kinetis,bioenergetics,metabolism,in vivo NMr,and biophotonics.As an engineer,physical chemist,physicist,physiologist,biophysicist,bioche...Britton Chance was a pioneer in many scientifc fields such as enzymatic reaction kinetis,bioenergetics,metabolism,in vivo NMr,and biophotonics.As an engineer,physical chemist,physicist,physiologist,biophysicist,biochemist,innovator and educator,he had worked indiversifed fields over extended periods bet ween 1926 until his death in 2010,at the age of 97.Inorder to illustrate his scientific career and great impact on research from a new perspective,weemploy scientometric analysis tools to analyze the publications of Britton Chance with datadownloaded from the ISI Citation Indexes in April 2013.We included articles,reviews andproceding papers but excluded meeting abstracts.In total,we obtained 1023 publication recordswith 1236 authors in 266 joumals with 17,114 citations from 1945 to 2013.We show the annualpublications and citations that Britton Chance received from 1945 to 2013,and generate HistCitemaps on the basis of the global citations(GCS)and local(sel)citations(LCS)to show thecitation relationships among the top-30 publications of Britton Chance.Metabolism and the development of physical methods to probe it appear to be the commecting thread of the lifelongresearch of Britton Chance.Furthermore,we generate the joumal map and co-authorship maptoshow the broad scope of research topics and collaborators and the high impacts of the scientificoeuvre of Britton Chance ranging from physics,engineering,chemistry and biology to medicine.展开更多
Huge amount of digital data of the Great East Japan Earthquake is provided by the highly-developed digital data technology. But the method and technique for analysis of these huge digital data are not developed suffic...Huge amount of digital data of the Great East Japan Earthquake is provided by the highly-developed digital data technology. But the method and technique for analysis of these huge digital data are not developed sufficiently. This paper proposes a running spectrum technique for text data and analyzing changes of disaster phase during the disaster management cycle. Impact analysis of the nuclear power plant accidents have been performed by using Fukushima Minpo newspaper for its verification. The result shows the dynamic characteristics of the nuclear power plant accidents. As the time interval B becomes longer, the analysis data is used from wide range period along with the smoothing effect. When observing different time intervals B, fewer keywords have been ranked in the longer time intervals of B. The proposed technique is a powerful tool to effective and efficient disaster response and management. analyze effectively the huge amount of digital data for the展开更多
The method,in which a few carats of diamond grits are placed inside a capsule together with a steel ball,shaken for a number of times,and the unbroken ratio of the grits is then used to evaluate the quality of the dia...The method,in which a few carats of diamond grits are placed inside a capsule together with a steel ball,shaken for a number of times,and the unbroken ratio of the grits is then used to evaluate the quality of the diamond,has been well established for many years.However,the unbroken percentage,in an equivalent view,represents the impact toughness of the grits and cannot reflect the value of the crushing energy.Most of the previous empirical formulas obtained from experiments by scholars cannot be applied to practical tests.In this paper,a dimensional analysis was applied to investigate the impact toughness experiment,and the dimensionless relationship has been built among those variables such as the toughness index,the impact time,the impact frequency and the crushing energy per unit area.According to the results of a large number of experiments with synthetic diamond grits of mesh size 45/50,the percentage of the broken grits H is proportional to the impact time T^(1.14) when the impact frequency is 2400 r/min,and the impact frequency f^(2.576) when the number of impacts is 2000.展开更多
Numerical climate models render data in a gridded format which is often problematic for integrated analysis with other kinds of data in jurisdictional formats. In this paper a joint analysis of municipal Gross Domesti...Numerical climate models render data in a gridded format which is often problematic for integrated analysis with other kinds of data in jurisdictional formats. In this paper a joint analysis of municipal Gross Domestic Product per capita (GDPc) and predicted temperature increase was undertaken in order to estimate different levels of human and economic exposure. This is based on a method of converting model outputs into a country municipal grid which enabled depicting climate predictions from the Eta-Hadgem2-ES Regional Climate Model (RCM) into the municipal level in Brazil. The conversion to country municipality grid was made using a combination of interpolation and buffering techniques in ArcGIS for two emission scenarios (RCP 4.5 and 8.5) and three timeframes (2011-2040, 2041-2070, 2071-2100) for mean temperature increase and number of heatwave days (WSDI). The results were used to support the Third National Communication (TCN) of Brazil to the United Nations Framework Convention on Climate Change (UNFCCC) and show a coherent matching of the gridded output from the original RCM. The joint climate and GDPc analysis show that in the beginning of the century the more severe warming is centred over regions where GDPc is generally higher (Centre-West and Southeast). At the end of the century, critical levels of warming spread north and northeastwards where municipalities have the lowest GDPc levels. In the high emission scenario (RCP 8.5), the strongest warming and the spreading over poorer regions are anticipated to the mid-century. These results are the key to further explore solutions for climate change adaptation based on current resources and prepare in different sectors, for long-term risk management and climate adaptation planning strategies.展开更多
There is a common difficulty in elastic-plastic impact codes such as EPIC[2,3] NONSAP[4], etc.. Most of these codes use the simple linear functions usually taken from static problem to represent the displacement compo...There is a common difficulty in elastic-plastic impact codes such as EPIC[2,3] NONSAP[4], etc.. Most of these codes use the simple linear functions usually taken from static problem to represent the displacement components. In such finite element formulation, the stress components are constant in each element and they are discontinuous in any two neighboring elements. Therefore, the bases of using the virtual work principle in such elements are unreliable. In this paper, we introduce a new method, namely, the compatible stress iterative method, to eliminate the above-said difficulty. The calculated examples show that the calculation using the new method in dynamic finite element analysis of high velocity impact is valid and stable, and the element stiffness can be somewhat reduced.展开更多
With the continuous development and progress of economy,people's living standard and culture level have been improved,but with it,there are also various kinds of life stress,study stress and work stress,which make...With the continuous development and progress of economy,people's living standard and culture level have been improved,but with it,there are also various kinds of life stress,study stress and work stress,which make people's mental health problems in life more andmore prominent,and how to improve students'mental health level is the main task of each education stage.The current psychology discipline system has been perfected,including personality psychology and social psychology,which are effectively applied in the actual mental health education or psychological guidance work,and are key disciplines to improve people's mental health.The theoretical system of personality and social psychology consists of three theories:the theory of planned behavior,the theory of explanatory levels,and the theory of self-determination,all of which have an irreplaceable influence on mental health.In this regard,this paper combines relevant literature and work experience to study in depth the influence of personality ansocial psychology on mental health.展开更多
This paper summarizes the approach, findings and evaluation methodology for a study that investigated the feasibility and potential impacts of street conversion options on traffic operations in downtown Birmingham, A...This paper summarizes the approach, findings and evaluation methodology for a study that investigated the feasibility and potential impacts of street conversion options on traffic operations in downtown Birmingham, Alabama. Of particular interest were issues related to conversion of grid systems from one-way to two-way operations. Recommendations on the most promising design and control configurations for implementation are also provided. A literature review was performed that threw light on the issues and challenges associated with implementation of street conversions, and the available best practices. A comprehensive traffic impact analysis that ensued employed the SYNCHRO computer simulation model to represent current and future operations so as to assess the implications of two-way conversions at and around the test sites. Detailed realistic two-way operations scenarios were developed that considered geometric and right-of-way restrictions, the location of land uses that generate and/or attract vehicular and pedestrian traffic, connectivity with the street grid, and accessibility to nearby freeway facilities, as well as practical concerns.展开更多
The superior climate conditions gave birth to excellent GongCheng per- simmon, and persimmon industry has become a pillar industry of Gongcheng farm- ers. In order to study the effects of extreme weather conditions on...The superior climate conditions gave birth to excellent GongCheng per- simmon, and persimmon industry has become a pillar industry of Gongcheng farm- ers. In order to study the effects of extreme weather conditions on the growth of GongCheng persimmon, 60 years of meteorological data and the basic cultivation information of persimmon over the years in Gongcheng County were collected and analyzed using factor corresponding analysis method, so as to study the extreme weather conditions, the influence mechanism on persimmon industry and the de- fense measures. The extreme weather conditions that have great effects are the continuous low temperature in spring, high temperature in summer, strong wind, hail, rainstorm, drought, and frost, which can affect the persimmon tree vigor, fruit bearing rate, plant diseases and pests as well as the quality of fruit. Focusing on mete- orological service, it needs to avoid the meteorological disasters as far as possible from orchard construction to management to ensure high quality and yield of persimmon.展开更多
Guilin sugar orange has advantages of good taste, harvest during the Spring Festival, marketable market, and it has got swift and violent development in recent years. Sugar orange yield and quality is closely related ...Guilin sugar orange has advantages of good taste, harvest during the Spring Festival, marketable market, and it has got swift and violent development in recent years. Sugar orange yield and quality is closely related to meteorological conditions, so in order to study the effect of meteorological conditions on the Guilin sugar orange, the local conditions of each orange-planting county in Guilin is analyzed, and study is also carried out on the severe weather and its defense measures. The suitable growth temperature for sugar orange is 23-29 ℃, and sugar orange is not tolerant to waterlogging and drought, like light, and has no resistance to ice cold. The main meteorological disasters include high temperature, low temperature, flood, drought, wind, hail, etc. Reasonable selection of orchard, scientific management, especially the management of plant diseases and insect pests, is the key to ensure high-quality high sand sugar orange.展开更多
Natural gas hydrate, as a potential energy resource, deposits in permafrost and marine sediment with large quantities. The current exploitation methods include depressurization, thermal stimulation, and inhibitor inje...Natural gas hydrate, as a potential energy resource, deposits in permafrost and marine sediment with large quantities. The current exploitation methods include depressurization, thermal stimulation, and inhibitor injection. However, many issues have to be resolved before the commercial production. In the present study, a 2-D axisymmetric simulator for gas production from hydrate reservoirs is developed. The simulator includes equations of conductive and convective heat transfer, kinetic of hydrate decomposition, and multiphase flow. These equations are discretized based on the finite difference method and are solved with the fully implicit simultaneous solution method. The process of laboratory-scale hydrate decomposition by depressurization is simulated. For different surrounding temperatures and outlet pressures, time evolutions of gas and water generations during hydrate dissociation are evaluated, and variations of temperature, pressure, and multiphase fluid flow conditions are analyzed. The results suggest that the rate of heat transfer plays an important role in the process. Furthermore, high surrounding temperature and low outlet valve pressure may increase the rate of hydrate dissociation with insignificant impact on final cumulative gas volume.展开更多
文摘BACKGROUND Myocardial infarction,particularly ST-segment elevation myocardial infarction(STEMI),is a key global mortality cause.Our study investigated predictors of mortality in 96 STEMI patients undergoing primary percutaneous coronary intervention at Erbil Cardiac Center.Multiple factors were identified influencing in-hospital mortality.Significantly,time from symptom onset to hospital arrival emerged as a decisive factor.Consequently,our study hypothesis is:"Reducing time from symptom onset to hospital arrival significantly improves STEMI prognosis."AIM To determine the key factors influencing mortality rates in STEMI patients.METHODS We studied 96 consecutive STEMI patients undergoing primary percutaneous coronary intervention(PPCI)at the Erbil Cardiac Center.Their clinical histories were compiled,and coronary evaluations were performed via angiography on admission.Data included comorbid conditions,onset of cardiogenic shock,complications during PPCI,and more.Post-discharge,one-month follow-up assessments were completed.Statistical significance was set at P<0.05.RESULTS Our results unearthed several significant findings.The in-hospital and 30-d mortality rates among the 96 STEMI patients were 11.2%and 2.3%respectively.On the investigation of independent predictors of in-hospital mortality,we identified atypical presentation,onset of cardiogenic shock,presence of chronic kidney disease,Thrombolysis In Myocardial Infarction grades 0/1/2,triple vessel disease,ventricular tachycardia/ventricular fibrillation,coronary dissection,and the no-reflow phenomenon.Specifically,the recorded average time from symptom onset to hospital arrival amongst patients who did not survive was significantly longer(6.92±3.86 h)compared to those who survived(3.61±1.67 h),P<0.001.These findings underscore the critical role of timely intervention in improving the survival outcomes of STEMI patients.CONCLUSION Our results affirm that early hospital arrival after symptom onset significantly improves survival rates in STEMI patients,highlighting the critical need for prompt intervention.
文摘1.This study is one of The Applied Economic Institutes Linkages Project(AERIL)which is funded by theCanadian International Development Agency(CIDA)and jiontly managed by The Conference Board of Canada(CBOC)and the International Trade Research Institute in China.It is jointly implemented by the Institute ofEconomic Research of the Chinese State Planning Commission and the North—South Institute of Canada。
基金supported by National Nature Science (Grant No. 41266002)
文摘The tropical cyclone that lands or passes through Guangxi coast is a serious natural disaster, which brings about strong winds, heavy rains, storm surges and other disasters causing severe damage of property or casualties in the coastal region every year. By counting and analyzing the tropical cyclones affecting Guangxi coast from 1950 to 2012, we find that the annual number of tropical cyclones changes significantly, and the maximum value can be up to 9, whereas the minimum value is 0 in some year. The regularity of seasonal distribution of tropical cyclones is obvious, and the peak period is in July, August and September every year, followed by June and October. Most of tropical cyclones come from the east of Philippines. After entering the South China Sea and passing through Hainan province and Leizhou Peninsula, they landed on Guangxi coast once again and caused the mean of peak surge reaching 111.2 cm, which is 2.6 times of non-landing typhoon. The formation of storm surge disaster is directly related to the severe typhoon weather systems, diurnal spring tide and discharge of river flood. Severe typhoons generate huge waves and rainfall, which lead to the rise of water level at the estuary, and would result in significant increasing water when stacking up with the storm surge, and cause huge tidal disaster.
文摘Using linear regression and correlation analysis method,the variation trend characteristics of average temperature,sunshine,precipitation and the phenology of five kinds of animals(Barn Swallows,Frogs,Cryptotympana atra,Crickets,Indian Cuckoo) in Huimin County during 1980-2008 were analyzed.On this basis,the relationship between the phenological phases of various animals and monthly temperature,sunshine and precipitation was analyzed.And the reasons that the phenological phases of various animals adapted to the climatic factors were also discussed.
基金supported by the National Science Foundation of China (Grants 11132007,11272203)
文摘In this paper,an efficien formulation based on the Lagrangian method is presented to investigate the contact–impact problems of f exible multi-body systems.Generally,the penalty method and the Hertz contact law are the most commonly used methods in engineering applications.However,these methods are highly dependent on various non-physical parameters,which have great effects on the simulation results.Moreover,a tremendous number of degrees of freedom in the contact–impact problems will influenc thenumericalefficien ysignificantl.Withtheconsideration of these two problems,a formulation combining the component mode synthesis method and the Lagrangian method is presented to investigate the contact–impact problems in fl xible multi-body system numerically.Meanwhile,the finit element meshing laws of the contact bodies will be studied preliminarily.A numerical example with experimental verificatio will certify the reliability of the presented formulationincontact–impactanalysis.Furthermore,aseries of numerical investigations explain how great the influenc of the finit element meshing has on the simulation results.Finally the limitations of the element size in different regions are summarized to satisfy both the accuracy and efficien y.
基金supported by the National Natural Science Foundation of China (51239009, 41171034)Shaanxi Provincial Natural Science Foundation of China (Key) Project (2013JZ012)+1 种基金Shaanxi Provincial Key Laboratory Project of Department of Education (14JS059)Shaanxi Provincial Water Conservancy Science and Technology Project (2016slkj-11)
文摘The Loess Plateau of China has experienced a lengthy drought and severe soil erosion.Changes in precipitation and land use largely determine the dynamics of runoff and sediment yield in this region. Trend and mutation analyses were performed on hydrological data(1981–2012) from the Yanwachuan watershed in the Loess Plateau Gully Region to study the evolution characteristics of runoff and sediment yield. A time-series contrasting method also was used to evaluate the effects of precipitation and soil and water conservation(SWC) on runoff and sediment yield. Annual sediment yield declined markedly from 1981 to 2012 although there was no significant change in annual precipitation and annual runoff. Change points of annual runoff and annual sediment yield occurred in 1996 and 1997,respectively. Compared with that in the baseline period(1981–1996), annual runoff and annual sediment yield in the change period(1997–2012)decreased by 17.0% and 76.0%, respectively, but annual precipitation increased by 6.3%. Runoff decreased in the flood season and normal season, but increased in the dry season, while sediment yield significantly declined in the whole study period. The SWC measures contributed significantly to the reduction of annual runoff(137.9%) and annual sediment yield(135%) and were more important than precipitation. Biological measures(forestland and grassland) accounted for 61.04% of total runoff reduction, while engineering measures(terraces and dams) accounted for 102.84% of total sediment yield reduction. Furthermore, SWC measures had positive ecological effects. This study provides a scientific basis for soil erosion control on the Loess Plateau.
文摘[Objective] The research aimed to study the influence of facility agriculture development on the climate variation in Weifang. [Method] Shouguang was selected as the representative station of greenhouse shed planting zone. By using the precipitation, temperature and relative humidity, etc. in Weifang City during 1961-2010, the climatic variation situations in the whole city and the greenhouse shed planting zone were analyzed. The variation trend and evolution characteristics of climate in the different seasons before and after the facility agriculture plantation were contrasted and analyzed. [Result] The annual rainfall and relative humidity presented the declining trend in the whole city in recent 50 years. The annual average, maximum and minimum temperatures all presented the rising trend. Since the large-scale plantation of greenhouse shed, the declining range of annual rainfall in the greenhouse shed planting zone was lower than that in the whole city, and the declining range of relative humidity was obviously higher than that in the whole city. The rising ranges of annual average, maximum and minimum temperatures were higher than that in the whole city. [Conclusion] The research provided the theory basis for the development of facility agriculture.
文摘Agricultural and rural economic policy system is one main driving force for the evolvement of agricultural Non-Point Source (NPS) pollution. In this paper, the main policies that influence agricultural NPS pollution are chosen, and a method to evaluate the impacts of agricultural and rural economic policy system on agricultural NPS pollution is brought forward. According to this, the questions about how and to what degree the policy system influence on agricultural NPS pollution are discussed.
文摘Database applications are becoming increasingly popular, mainly due to the advanced data management facilities that the underlying database management system offers compared against traditional legacy software applications. The interaction, however, of such applications with the database system introduces a number of issues, among which, this paper addresses the impact analysis of the changes performed at the database schema level. Our motivation is to provide the software engineers of database applications with automated methods that facilitate major maintenance tasks, such as source code corrections and regression testing, which should be triggered by the occurrence of such changes. The presented impact analysis is thus two-folded: the impact is analysed in terms of both the affected source code statements and the affected test suites concerning the testing of these applications. To achieve the former objective, a program slicing technique is employed, which is based on an extended version of the program dependency graph. The latter objective requires the analysis of test suites generated for database applications, which is accomplished by employing testing techniques tailored for this type of applications. Utilising both the slicing and the testing techniques enhances program comprehension of database applications, while also supporting the development of a number of practical metrics regarding their maintainability against schema changes. To evaluate the feasibility and effectiveness of the presented techniques and metrics, a software tool, called DATA, has been implemented. The experimental results from its usage on the TPC-C case study are reported and analysed.
基金the National Defence Foundation of Science & Technology of China (No.J14.8.1.JW0515)
文摘Based on linearized 2-D Navier-Stokes equation, a Laplacetransform-boundary element coupling method for viscousfluid-structure impact analysis is proposed. Under assumption ofincompressibility for the fluid, the corresponding equivalentboundary integral equation in terms of the potential function andstream function is first established by Lamb's transform in theLaplace transform domain.
文摘Britton Chance was a pioneer in many scientifc fields such as enzymatic reaction kinetis,bioenergetics,metabolism,in vivo NMr,and biophotonics.As an engineer,physical chemist,physicist,physiologist,biophysicist,biochemist,innovator and educator,he had worked indiversifed fields over extended periods bet ween 1926 until his death in 2010,at the age of 97.Inorder to illustrate his scientific career and great impact on research from a new perspective,weemploy scientometric analysis tools to analyze the publications of Britton Chance with datadownloaded from the ISI Citation Indexes in April 2013.We included articles,reviews andproceding papers but excluded meeting abstracts.In total,we obtained 1023 publication recordswith 1236 authors in 266 joumals with 17,114 citations from 1945 to 2013.We show the annualpublications and citations that Britton Chance received from 1945 to 2013,and generate HistCitemaps on the basis of the global citations(GCS)and local(sel)citations(LCS)to show thecitation relationships among the top-30 publications of Britton Chance.Metabolism and the development of physical methods to probe it appear to be the commecting thread of the lifelongresearch of Britton Chance.Furthermore,we generate the joumal map and co-authorship maptoshow the broad scope of research topics and collaborators and the high impacts of the scientificoeuvre of Britton Chance ranging from physics,engineering,chemistry and biology to medicine.
文摘Huge amount of digital data of the Great East Japan Earthquake is provided by the highly-developed digital data technology. But the method and technique for analysis of these huge digital data are not developed sufficiently. This paper proposes a running spectrum technique for text data and analyzing changes of disaster phase during the disaster management cycle. Impact analysis of the nuclear power plant accidents have been performed by using Fukushima Minpo newspaper for its verification. The result shows the dynamic characteristics of the nuclear power plant accidents. As the time interval B becomes longer, the analysis data is used from wide range period along with the smoothing effect. When observing different time intervals B, fewer keywords have been ranked in the longer time intervals of B. The proposed technique is a powerful tool to effective and efficient disaster response and management. analyze effectively the huge amount of digital data for the
基金Supported by the National Natural Science Foundation of China(11572047)
文摘The method,in which a few carats of diamond grits are placed inside a capsule together with a steel ball,shaken for a number of times,and the unbroken ratio of the grits is then used to evaluate the quality of the diamond,has been well established for many years.However,the unbroken percentage,in an equivalent view,represents the impact toughness of the grits and cannot reflect the value of the crushing energy.Most of the previous empirical formulas obtained from experiments by scholars cannot be applied to practical tests.In this paper,a dimensional analysis was applied to investigate the impact toughness experiment,and the dimensionless relationship has been built among those variables such as the toughness index,the impact time,the impact frequency and the crushing energy per unit area.According to the results of a large number of experiments with synthetic diamond grits of mesh size 45/50,the percentage of the broken grits H is proportional to the impact time T^(1.14) when the impact frequency is 2400 r/min,and the impact frequency f^(2.576) when the number of impacts is 2000.
基金the United Nations Programme for Development(UNDP),Rede Clima(FINEP 01.13.0353.00)the Brazilian Ministry for Science and Technology for their financial support
文摘Numerical climate models render data in a gridded format which is often problematic for integrated analysis with other kinds of data in jurisdictional formats. In this paper a joint analysis of municipal Gross Domestic Product per capita (GDPc) and predicted temperature increase was undertaken in order to estimate different levels of human and economic exposure. This is based on a method of converting model outputs into a country municipal grid which enabled depicting climate predictions from the Eta-Hadgem2-ES Regional Climate Model (RCM) into the municipal level in Brazil. The conversion to country municipality grid was made using a combination of interpolation and buffering techniques in ArcGIS for two emission scenarios (RCP 4.5 and 8.5) and three timeframes (2011-2040, 2041-2070, 2071-2100) for mean temperature increase and number of heatwave days (WSDI). The results were used to support the Third National Communication (TCN) of Brazil to the United Nations Framework Convention on Climate Change (UNFCCC) and show a coherent matching of the gridded output from the original RCM. The joint climate and GDPc analysis show that in the beginning of the century the more severe warming is centred over regions where GDPc is generally higher (Centre-West and Southeast). At the end of the century, critical levels of warming spread north and northeastwards where municipalities have the lowest GDPc levels. In the high emission scenario (RCP 8.5), the strongest warming and the spreading over poorer regions are anticipated to the mid-century. These results are the key to further explore solutions for climate change adaptation based on current resources and prepare in different sectors, for long-term risk management and climate adaptation planning strategies.
文摘There is a common difficulty in elastic-plastic impact codes such as EPIC[2,3] NONSAP[4], etc.. Most of these codes use the simple linear functions usually taken from static problem to represent the displacement components. In such finite element formulation, the stress components are constant in each element and they are discontinuous in any two neighboring elements. Therefore, the bases of using the virtual work principle in such elements are unreliable. In this paper, we introduce a new method, namely, the compatible stress iterative method, to eliminate the above-said difficulty. The calculated examples show that the calculation using the new method in dynamic finite element analysis of high velocity impact is valid and stable, and the element stiffness can be somewhat reduced.
文摘With the continuous development and progress of economy,people's living standard and culture level have been improved,but with it,there are also various kinds of life stress,study stress and work stress,which make people's mental health problems in life more andmore prominent,and how to improve students'mental health level is the main task of each education stage.The current psychology discipline system has been perfected,including personality psychology and social psychology,which are effectively applied in the actual mental health education or psychological guidance work,and are key disciplines to improve people's mental health.The theoretical system of personality and social psychology consists of three theories:the theory of planned behavior,the theory of explanatory levels,and the theory of self-determination,all of which have an irreplaceable influence on mental health.In this regard,this paper combines relevant literature and work experience to study in depth the influence of personality ansocial psychology on mental health.
文摘This paper summarizes the approach, findings and evaluation methodology for a study that investigated the feasibility and potential impacts of street conversion options on traffic operations in downtown Birmingham, Alabama. Of particular interest were issues related to conversion of grid systems from one-way to two-way operations. Recommendations on the most promising design and control configurations for implementation are also provided. A literature review was performed that threw light on the issues and challenges associated with implementation of street conversions, and the available best practices. A comprehensive traffic impact analysis that ensued employed the SYNCHRO computer simulation model to represent current and future operations so as to assess the implications of two-way conversions at and around the test sites. Detailed realistic two-way operations scenarios were developed that considered geometric and right-of-way restrictions, the location of land uses that generate and/or attract vehicular and pedestrian traffic, connectivity with the street grid, and accessibility to nearby freeway facilities, as well as practical concerns.
文摘The superior climate conditions gave birth to excellent GongCheng per- simmon, and persimmon industry has become a pillar industry of Gongcheng farm- ers. In order to study the effects of extreme weather conditions on the growth of GongCheng persimmon, 60 years of meteorological data and the basic cultivation information of persimmon over the years in Gongcheng County were collected and analyzed using factor corresponding analysis method, so as to study the extreme weather conditions, the influence mechanism on persimmon industry and the de- fense measures. The extreme weather conditions that have great effects are the continuous low temperature in spring, high temperature in summer, strong wind, hail, rainstorm, drought, and frost, which can affect the persimmon tree vigor, fruit bearing rate, plant diseases and pests as well as the quality of fruit. Focusing on mete- orological service, it needs to avoid the meteorological disasters as far as possible from orchard construction to management to ensure high quality and yield of persimmon.
文摘Guilin sugar orange has advantages of good taste, harvest during the Spring Festival, marketable market, and it has got swift and violent development in recent years. Sugar orange yield and quality is closely related to meteorological conditions, so in order to study the effect of meteorological conditions on the Guilin sugar orange, the local conditions of each orange-planting county in Guilin is analyzed, and study is also carried out on the severe weather and its defense measures. The suitable growth temperature for sugar orange is 23-29 ℃, and sugar orange is not tolerant to waterlogging and drought, like light, and has no resistance to ice cold. The main meteorological disasters include high temperature, low temperature, flood, drought, wind, hail, etc. Reasonable selection of orchard, scientific management, especially the management of plant diseases and insect pests, is the key to ensure high-quality high sand sugar orange.
基金supported by the National High Technology Research and Development Program of China(863 Program, Grant No.2006AA09A209-5)the National Natural Science Foundation of China (Key Program,Grant No.50736001)the Major Research Project of Ministry of Education of China (Grant No.306005)
文摘Natural gas hydrate, as a potential energy resource, deposits in permafrost and marine sediment with large quantities. The current exploitation methods include depressurization, thermal stimulation, and inhibitor injection. However, many issues have to be resolved before the commercial production. In the present study, a 2-D axisymmetric simulator for gas production from hydrate reservoirs is developed. The simulator includes equations of conductive and convective heat transfer, kinetic of hydrate decomposition, and multiphase flow. These equations are discretized based on the finite difference method and are solved with the fully implicit simultaneous solution method. The process of laboratory-scale hydrate decomposition by depressurization is simulated. For different surrounding temperatures and outlet pressures, time evolutions of gas and water generations during hydrate dissociation are evaluated, and variations of temperature, pressure, and multiphase fluid flow conditions are analyzed. The results suggest that the rate of heat transfer plays an important role in the process. Furthermore, high surrounding temperature and low outlet valve pressure may increase the rate of hydrate dissociation with insignificant impact on final cumulative gas volume.