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Distribution law and susceptibility of geohazards across a gradient belt of the Western Sichuan Plateau
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作者 LI Tianbin WANG Jianfeng +4 位作者 HE Chaoyang MENG Lubo LI Chaofei MA Junjie WEI Daqiang 《Journal of Mountain Science》 SCIE CSCD 2024年第6期1849-1867,共19页
Across a gradient belt of the Western Sichuan Plateau,geohazards have seriously limited economic and social development.According to incomplete statistics,15,673 geohazards have been recorded in the study area.In orde... Across a gradient belt of the Western Sichuan Plateau,geohazards have seriously limited economic and social development.According to incomplete statistics,15,673 geohazards have been recorded in the study area.In order to mitigate the threat of geohazards to human engineering activities in the region,an overall understanding of the distribution pattern of geohazards and susceptibility assessment are necessary.In this paper,a gradient belt of the Western Sichuan Plateau and its zoning criteria were defined.Subsequently,on the basis of relief amplitude,distance to faults,rainfall,and human activities,three indicators of endogenic process were introduced:Bouguer gravity anomaly gradient,vertical deformation gradient,and horizontal deformation gradient.Thereafter,the distribution patterns of geohazards were investigated through mathematical statistics and ArcGIS software.By randomly selecting 10,449 hazards,a geohazard susceptibility map was generated using the Information Value(IV)model.Finally,the IV model was validated against 5224 hazards using the Area Under Curve(AUC)method.The results show that 47.6%of the geohazards were distributed in the zone of steep slope.Geohazards showed strong responses to distance to faults,human activities,and annual rainfall.The distribution of geohazards in the gradient belt of the Western Sichuan Plateau is more sensitive to vertical internal dynamics factors(such as vertical deformation gradient and Bouguer gravity anomaly gradient)without any apparent sensitivity to horizontal internal dynamics factors.The areas of high and very-high risk account for up to 32.22%,mainly distributed in the Longmenshan and Anning River faults.According to the AUC plot,the success rate of the IV model for generating the susceptibility map is 76%.This susceptibility map and geohazard distribution pattern can provide a reference for geological disaster monitoring,preparation of post-disaster emergency measures,and town planning. 展开更多
关键词 Gradient belt GEOHAZARDS distribution law Bouguer Gravity anomaly gradient Vertical deformation gradient SUSCEPTIBILITY
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Sand-dust storms in China: temporal-spatial distribution and tracks of source lands 被引量:11
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作者 QIU Xin-fa1, ZENG Yan2, MIAO Qi-long2 (1. Urban & Resource Department, Nanjing University, Nanjing 210009, China 2. Department of Environmental Science, Nanjing Institute of Meteorology, Nanjing 210044, China) 《Journal of Geographical Sciences》 SCIE CSCD 2001年第3期253-260,共9页
Sand-dust storm is a special natural disaster that frequently occurs in deserts and their surrounding areas. With the data published onSurface Meteorological Monthly Bulletin andSurface Chart during 1971–1996, the te... Sand-dust storm is a special natural disaster that frequently occurs in deserts and their surrounding areas. With the data published onSurface Meteorological Monthly Bulletin andSurface Chart during 1971–1996, the temporal-spatial distribution and annual variation of sand-dust storms are analyzed on the basis of the case study of atmospheric processes. Furthermore, the tracks and source areas of sand-dust storms are determined with the aid of GIS. The results show that except some parts of Qinghai Province and Inner Mongolia as well as Beijing, sand-dust storms decrease apparently in time and space in recent decades in China. Sand-dust storms occur most frequently in spring, especially in April. According to their source areas, sand-dust storms are classified into two types, i.e., the inner-source and outer-source sand-dust storms. Most of the outer-source sand-dust storms move along the north and west tracks. The north-track outer-source sand-dust storms always intrude into China across the Sino-Mongolian border from Hami, a city in the eastern part ofXinjiang, to Xilin Gol, a league in Inner Mongolia, while the west-track ones intrude into China from both southern and northern Xinjiang. The source lands of inner-source sand-dust storms concentrate in the Taklimakan Desert and its surrounding areas in southern Xinjiang, southern part of the Junggar Basin in north of Xinjiang, the Hexi Corridor in western Gansu Province, the dry deserts of Inner Mongolia and the Qaidam Basin in Qinghai. 展开更多
关键词 sand-dust storm temporal-spatial distribution TRACKS source lands
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Temporal-spatial distribution and variability of cadmium contamination in soils in Shenyang Zhangshi irrigation area,China 被引量:8
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作者 SUN Li-na ZHANG Yao-hua +3 位作者 SUN Tie-heng GONG Zong-qiang LIN Xin LI Hai-bo 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2006年第6期1241-1246,共6页
Heavy metal contamination in soils has been of wide concern in China in the last several decades. The heavy metal contamination was caused by sewage irrigation, mining and inappropriate utilization of various agrochem... Heavy metal contamination in soils has been of wide concern in China in the last several decades. The heavy metal contamination was caused by sewage irrigation, mining and inappropriate utilization of various agrochemicals and pesticides and so on. The Shenyang Zhangshi irrigation area (SZIA) in China is a representative area of heavy metal contamination of soils resulting from sewage irrigation for about 30 years duration. This study investigated the spatial distribution and temporal variation of soil cadmium contamination in the SZIA. The soil samples were collected from the SZIA in 1990 and 2004; Cd of soils was analyzed and then the spatial distribution and temporal variation of Cd in soils was modelled using kriging methods. The kriging map showed that long-term sewage irrigation had caused serious Cd contamination in topsoil and subsoil. In 2004, the Cd mean concentrations were 1.698 and 0.741 mg/kg, and the maxima 10.150 and 7.567 mg/kg in topsoils (0-20 cm) and subsoils (20-40 cm) respectively. These values are markedly more than the Cd levels in the second grade soil standard in China. In 1990, the Cd means were 1.023 and 0.331 mg/kg, and the maxima 9.400 and 3.156 mg/kg, in topsoils and subsoils respectively. The soil area in 1990 with Cd more than 1.5 mg/kg was 2701 and 206.4 hnl2 in topsoils and subsoils respectively; and in 2004, it was 7592 and 1583 hm^2, respectively. Compared with that in 1990, the mean and maximum concentration of Cd, as well as the soil area with Cd more than 1.5 mg/kg had all increased in 2004, both in topsoils and subsoils. 展开更多
关键词 temporal-spatial distribution cadmium contamination of soil Zhangshi sewage irrigation area (ZSIA) Shenyang
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Impact of Holocene environmental change on temporal-spatial distribution of Neolithic sites in Huaihe River Basin, Anhui Province 被引量:5
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作者 HUANG Run ZHU Cheng +1 位作者 GUAN Yong ZHENG Chaogui 《Journal of Geographical Sciences》 SCIE CSCD 2006年第2期199-208,共10页
The Huaihe River basin of Anhui is not only a transitional zone of physical geography, but also a convergent area of many cultures in China. It is one of the sensitive ecotones to global changes and the birthplace of ... The Huaihe River basin of Anhui is not only a transitional zone of physical geography, but also a convergent area of many cultures in China. It is one of the sensitive ecotones to global changes and the birthplace of Chinese civilization. Using the field archaeological data and the sporo-pollens and the age data of the drilling cores, we analysed Neolithic cultural development and environmental evolution in the Huaihe River basin of Anhui. According to the combination of some research results in archaeology with environmental evolution research, this paper discusses the relationship between culture and environment in the Huaihe River basin of Anhui. The Neolithic cultural development was strongly impacted by the environmental change. The primitive culture (Shishanzi) was developed in the beginning of the Holocene Megathermal Period with distinct regional feature of the culture. From 6.5 kaBP to 5.5 kaBP, the climate changed warmer and wetter. The frequent occurrence of flood and waterlog due to such a climate regime and high sea level caused the earth's surface environment deteriorated in the Huaihe River basin of Anhui and the interruption of the Neolithic cultural development, hence a lack of archaeological sites. From 5.5 kaBP to 4.0 kaBP, the climate changed from wet to dry, the natural environment was propitious to human survival. Dawenkou Culture and Longshan Culture flourished in this period. The Neolithic cultural development, the number of the sites and their distribution characteristics of the sites in the study area differed apparently from those in Central China and Shandong Province. 展开更多
关键词 HOLOCENE environmental change Neolithic site temporal-spatial distribution Huaihe Riverbasin of Anhui
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Temporal-spatial Distribution and Short-range Prediction Indicators of Hail Weather in East Central Haixi Prefecture of Qinghai Province 被引量:2
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作者 Xiuping Cheng Chengtao Shan +1 位作者 Gasang Pei Na Wang 《Meteorological and Environmental Research》 CAS 2013年第4期21-25,共5页
[ Objective] The study aimed to discuss the temporal-spatial distribution and short-range prediction indicators of hail weather in east central Haixi Prefecture of Qinghai Province. [Method] Using hail data of six sta... [ Objective] The study aimed to discuss the temporal-spatial distribution and short-range prediction indicators of hail weather in east central Haixi Prefecture of Qinghai Province. [Method] Using hail data of six stations in east central Haixi Prefecture from 1960 to 2010, the temporal and spatial distribution of hail weather was analyzed firstly. Afterwards, based on the high-altitude factual data of 30 case studies of hail during 2006 -2010, its high-altitude and ground weather situation and physical quantity field were studied to summarize short-term circulation pattern and shod- range prediction characteristics of hail weather. [ Result] In east central Haixi, hail appeared from April to September, and it was most frequently from May to August. Meanwhile, hail was frequent from 14:00 to 20:00. Among the six stations, hail was most frequent in Tianjun but least frequent in Wulan. Moreover, hail disaster mainly occurred in Wulan and Tianjun. In addition, there were three typos of circulation pattern of hail weather at 500 hPa. Hail mainly occurred under the effect of northwest airflow, and it had shortwave trough, cold center or trough, jet stream core or one of the three. Hail appeared frequently under the situation of upper-level divergence and low-level convergence, and abundant water vapor and water vapor flux convergence at low levels were important conditions for hailing. [ Conclusion] The research could provide scientific references for improving the accuracy of hail forecast. 展开更多
关键词 East central Haixi Prefecture HAIL temporal-spatial distribution Physical quantity field Short-range prediction indicators China
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Temporal-spatial Distribution of Various Types of Crime in the Special Wards of Tokyo 被引量:1
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作者 Zhuo LIU Hui LIN +1 位作者 Qinghua HE Yuling WANG 《Journal of Geodesy and Geoinformation Science》 2022年第2期19-28,共10页
Based on the official criminal data released by the Tokyo Metropolitan Police Department in 2019,this paper discusses the temporal-spatial distribution of various types of crimes in the special wards of Tokyo.The resu... Based on the official criminal data released by the Tokyo Metropolitan Police Department in 2019,this paper discusses the temporal-spatial distribution of various types of crimes in the special wards of Tokyo.The results show that:(1)The times of high and low incidence of different types of crime differ significantly.Although vicious crime and violent crime present no obvious monthly distribution,property crime clearly differs between the first and second half of a calendar year.(2)The month before the new year sees a surge in most types of crime.(3)Vicious crime peaks in the hours between night and early morning.Violent crime and property crime correlate positively with the frequency of human interaction and peak in the morning and evening commuting hours.(4)The spatial distribution of crime resembles the concentric circles of the three rings of the special wards of Tokyo,with a central high-incidence area,a center-peripheral low-incidence area,and a marginal high-incidence area.In addition,the center sees more personal crime than the periphery,whereas property crimes show the opposite trend.(5)A spatial autocorrelation analysis shows that the special wards of Tokyo may be grouped into the“high-high”and“low-low”agglomeration modes of different types of crime,with marked differences between the various types of crime.The crime can be divided into three types:central agglomeration,double central agglomeration,and decentralized agglomeration. 展开更多
关键词 crime geography temporal-spatial distribution spatial analysis special wards of Tokyo
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Study on the Temporal-spatial Distribution Characteristics of Extreme Precipitation in Jiangsu Province
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作者 Tengfei Zheng Xin Yu Jianmao Guo 《Meteorological and Environmental Research》 CAS 2013年第8期1-6,共6页
[Objective] The rasearch aimed to grasp the spatial and temporal distribution charactedstics of extreme precipitation in Jiangsu Prov- ince. [Methodl Threshold was determined by detrended fluctuation analysis (DFA) ... [Objective] The rasearch aimed to grasp the spatial and temporal distribution charactedstics of extreme precipitation in Jiangsu Prov- ince. [Methodl Threshold was determined by detrended fluctuation analysis (DFA) based on the data of daily precipitation over Jiangsu Province from 1961 to 2010, and the oscillation pedod and mutation were detected by the method of Morlet wavelet analysis and Mann-Kendall test respec- tively. [ Result~ The annual frequency of extreme precipitation in Jiangsu Province demonstrated oscillation characteristics with 8 -10 a, and the mutation mainly happened in 2006, In addition, the oscillation period of extreme precipitation during summer was 8 -10 a, and its mutation hap- pened in 1998. The oscillation periods of extreme precipitation, however, during autumn were 2 -3 and 5 -7 a. Extreme precipitation and total rain- fall had better consistency. They both presented the characteristics of more in the south and less in the north, and big-small-value zone was concentrated. [ Conclusion] The research could provide technical support for making defense policy of the related disaster for relevant departments. 展开更多
关键词 Detrended fluctuation analysis Extreme precipitation temporal-spatial distribution China
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Study on Temporal-spatial Distribution of Heavy Rain and Rainstorm in Different Functional Areas of Chongqing
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作者 Yuan Lin Mou Xinli +2 位作者 Zhang Meng Gu Yi Zhou Jie 《Meteorological and Environmental Research》 CAS 2014年第9期7-10,共4页
To discuss response ability of five functional areas to rainstorm flood in Chongqing,by taking 8 districts( counties) as research object,monthly occurrence times of heavy rain and rainstorm in different functional a... To discuss response ability of five functional areas to rainstorm flood in Chongqing,by taking 8 districts( counties) as research object,monthly occurrence times of heavy rain and rainstorm in different functional areas over the years and appearance month of the maximum rainfall were conducted statistics. Results showed that frequency distribution of heavy rain in whole year in different functional areas was different,but it was similar in the same functional zone. Temporal-spatial distribution of rainstorm was more independent,and there were different performances in various districts of each functional area. In urban functional core area and urban functional expansion area,rainstorm times was more,and the maximum precipitation was larger. In urban development new district,rainstorm times and the maximum precipitation were relatively smaller in whole Chongqing. In ecological conservation development area of northeast Chongqing,rainstorm duration was longer,and we needed prevention and control during June- September. In ecological protection area of southeast Chongqing,although rainstorm occurrence times was the most in Chongqing,the heavy rainstorm was less. 展开更多
关键词 Heavy rain Rainstorm Functional area temporal-spatial distribution Chongqing China
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CONCEPT, DISTRIBUTION LAW AND FORMATION MACHANISM OF INLAND SALINE ALKALINE WETLAND─ ─ Taking Songliao Plain for Example 被引量:5
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作者 SUN Guang you1, LUO Xin zheng2 , YI Fu ke1 , ZHANG Xiao ping1 (1.Changchun Institute of Geography, the Chinese Academy of Sciences,Changchun 130021,P.R.China 2.Institute of Geography, Academy of Henan Province, Zhengzhou 450052,P.R.China) 《Chinese Geographical Science》 SCIE CSCD 2000年第3期63-69,共2页
The paper, taking Songliao Plain for example, studied the concept, distribution law and formation mechanism of inland saline alkaline wetland. The inland saline alkaline wetland is distributed over the inland region o... The paper, taking Songliao Plain for example, studied the concept, distribution law and formation mechanism of inland saline alkaline wetland. The inland saline alkaline wetland is distributed over the inland region of arid or semi arid climate; it is the wet or slightly stagnant environment, forming saline alkaline soil and salt vegetation and making the geogra phical environment fonming complex with an ecosystem of saline alkaline wetland. The laws of zone nature and non zone nature control the distribution of the inland saline alkaline wetland that extensively spreads in north part of China and other countries. The inland saline alkaline wetland is formed jointly by atmosphere, hydrosphere, lithosphere and biosphere including intellectual sphere. Under the special condition, the artificial activity is possibly the key function. In order to improve the human environment, it is a great duty confronting the whole world to rationally transform the inland saline alkaline wetland. Therefore, we presented an anti inland theory to promote the environment transformation. 展开更多
关键词 Songliao Plain INLAND SALINE ALKALINE WETLAND WETLAND distribution law WETLAND CONCEPT WETLAND FORMATION mechanism
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A Research of the Finding and Distribution Law of Taisui in Modern China 被引量:11
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作者 Chao-Jiang Wang Shi-Qing Wang 《Agricultural Sciences》 2015年第4期407-414,共8页
The academic world is still uncertain about the classification of Taisui. It is debating whether Taisui is living or not, myxomycete complex or fungi. The passage studies the 228 finding reports of Taisui in modern Ch... The academic world is still uncertain about the classification of Taisui. It is debating whether Taisui is living or not, myxomycete complex or fungi. The passage studies the 228 finding reports of Taisui in modern China. It confirms that the first finding time of Taisui in modern China is 1963, and the first reported time is 1992. Taisui has been found in 25 administrative divisions. Taisui occurs the most times in Shandong Province. Besides, provinces where Taisui has been found most times are in northern China. Finding locations of Taisui vary from place to place. Taisui is most often found in normal earth layer, with different burying depth. Taisui is mainly found through seeing, tramping, and digging. Taisui findings lack subjective motivations and are connected with the life and production of the finders. Conclusion: Taisui is an object growing in earth layer. 展开更多
关键词 Taisui Finding law distribution law China in MODERN TIMES
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Seepage field distribution and water inflow laws of tunnels in water-rich regions 被引量:6
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作者 LI Zheng CHEN Zi-quan +2 位作者 HE Chuan MA Chun-chi DUAN Chao-ran 《Journal of Mountain Science》 SCIE CSCD 2022年第2期591-605,共15页
Currently,the water inrush hazards during tunnel construction,the water leakage during tunnel operation,and the accompanying disturbances to the ecological environment have become the main problems that affect the str... Currently,the water inrush hazards during tunnel construction,the water leakage during tunnel operation,and the accompanying disturbances to the ecological environment have become the main problems that affect the structural safety of tunnels in water-rich regions.In this paper,a tunnel seepage model testing system was used to conduct experiments of the grouting circle and primary support with different permeability coefficients.The influences of the supporting structures on the water inflow laws and the distribution of the water pressure in the tunnel were analyzed.With the decrease in the permeability coefficient of the grouting circle or the primary support,the inflow rate of water into the tunnel showed a non-linear decreasing trend.In comparison,the water inflow reduction effect of grouting circle was much better than that of primary support.With the increase of the permeability coefficient of the grouting ring,the water pressure behind the primary lining increases gradually,while the water pressure behind the grouting ring decreases.Thus,the grouting of surrounding rock during the construction of water-rich tunnel can effectively weaken the hydraulic connection,reduce the influence range of seepage,and significantly reduce the decline of groundwater.Meanwhile,the seepage tests at different hydrostatic heads and hydrodynamic heads during tunnel operation period were also conducted.As the hydrostatic head decreased,the water pressure at each characteristic point decreased approximately linearly,and the water inflow rate also had a gradual downward trend.Under the action of hydrodynamic head,the water pressure had an obvious lagging effect,which was not conducive to the stability of the supporting structures,and it could be mitigated by actively regulating the drainage rate.Compared with the hydrostatic head,the hydrodynamic head could change the real-time rate of water inflow to the tunnel and broke the dynamic balance between the water pressure and water inflow rate,thereby affecting the stress state on the supporting structures. 展开更多
关键词 Water-rich tunnel Seepage field distribution Water inflow law Construction period Operation period
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Spatial and Temporal Distribution of Different Grades of Short-time Precipitation in Xining City
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作者 Liang XU Yongling SU 《Meteorological and Environmental Research》 CAS 2023年第1期21-23,共3页
Based on the hourly precipitation data from 4 observation stations of Xining City from June to September during 2005-2011,the temporal and spatial distribution characteristics of short-time precipitation were analyzed... Based on the hourly precipitation data from 4 observation stations of Xining City from June to September during 2005-2011,the temporal and spatial distribution characteristics of short-time precipitation were analyzed.The results show that the precipitation distribution in Xining region exhibited the less-more-less trend from southwest to northeast,while the torrential rain gradually increased from the northwest and southwest to the middle.The hourly general precipitation in Xining region had obviously seasonal characteristics,and its annual distribution showed wavy changes,but the annual variation of short-time heavy precipitation and rainstorm was very obvious.Furthermore,short-time heavy precipitation was concentrated from 18:00 to 24:00,followed by 03:00-07:00 on the following day.The occurrence time of short-time rainstorm accorded with short-time heavy precipitation.It offers a useful reference for the accurate and timely short-term forecast. 展开更多
关键词 DIFFERENT GRADES Short-time PRECIPITATION temporal-spatial distribution
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Applicability of law of mass action to distribution of manganese between slag melts and liquid iron 被引量:1
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作者 张鉴 《中国有色金属学会会刊:英文版》 CSCD 2001年第5期778-783,共6页
According to the law of mass action and the coexistence theory of slag structure, the distribution of manganese between MnO FeO SiO 2 and MgO MnO FeO SiO 2 slag melts as well as liquid iron was analyzed. It is shown t... According to the law of mass action and the coexistence theory of slag structure, the distribution of manganese between MnO FeO SiO 2 and MgO MnO FeO SiO 2 slag melts as well as liquid iron was analyzed. It is shown that K ′ Mn and K MnO are only dependent on temperature and don’t change with basicities and compositions of slag melts. So the distribution of manganese between the above mentioned slag melts and molten iron obeys the law of mass action. But analysis of experimental results from other sources shows that K ′ Mn and K MnO really change with basicities of slag, which is probably arisen from not approaching equilibrium under low basicity slag melts. 展开更多
关键词 manganese distribution the law of mass action the coexistence theory of slag structure mass action concentration
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Relativistic Corrections to the Maxwellian Distribution for Astrophysical and Fusion Plasmas
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作者 Amaury de Kertanguy 《Journal of Applied Mathematics and Physics》 2023年第8期2414-2428,共15页
We present calculations and improvement inspired by the work of Lorenzo Zaninetti, published in 2020, it concerns a problem whose origin dates back 1911 with so called Maxwell-Jüttner distribution these lies on t... We present calculations and improvement inspired by the work of Lorenzo Zaninetti, published in 2020, it concerns a problem whose origin dates back 1911 with so called Maxwell-Jüttner distribution these lies on the Lorentz factor , with . This work uses powerful modern software for a reconstruction of Zaninetti work, which computes with special functions, these are included in the Mathematica software, as by instance Bessel and Meijer G-functions ready to manipulate. A progress is made, it is possible to perform an integral that is not computed in Zaninetti paper. This author connects the correct relativistic probability law: the Maxwell-Jüttner to the synchrotron emissivity with a magnetic B field, this work generalize these results, using the linear Stark effect and deals with an electric field E. 展开更多
关键词 Maxwell-Jüttner distribution Relativity Modification to Maxwell law Lorentz Factor Linear Stark Effect Plasma Physics
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Plastic zone distribution laws and its types of surrounding rock in large-span roadway 被引量:14
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作者 Li Chong Xu Jinhai +1 位作者 PanJianzhong Ma Chao 《International Journal of Mining Science and Technology》 2012年第1期23-28,共6页
In order to study the distribution laws and types of plastic zone of surrounding rock in large-span roadway, we analyzed the distribution laws with different spans and lateral pressures using FLAC 3D numerical calcula... In order to study the distribution laws and types of plastic zone of surrounding rock in large-span roadway, we analyzed the distribution laws with different spans and lateral pressures using FLAC 3D numerical calculation software. Based on the roadway support difficulty and distribution laws of the plastic zone of surrounding rock, we defined the large-span roadway and classified the types of large-span rectangular roadways. As a result, the distribution laws of the plastic zone on surrounding rock in a rectangular roadway with different spans and lateral pressures were obtained. The results show that the area of the plastic zone on surrounding rock increased with the increase of the spans and lateral pressures, and the plastic zone was symmetrical to the center line of roadway. At k = 0.5, 1.0, 1.5, and 2.0, the plastic zone presented "addleshape" distribution, "ellipse" distribution, "thin and high" distribution and "inverse trapezium" distribution, respectively. In addition, we classified the roadways into four types according to the different lateral pressures and spans, including small-span, moderate-span, large-span and extreme-large-span roadways. 展开更多
关键词 大跨度巷道 围岩塑性区 分布规律 围岩类型 横向压力 FLAC3D 矩形巷道 四舍五入
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Revisiting the Curie-Von Schweidler Law for Dielectric Relaxation and Derivation of Distribution Function for Relaxation Rates as Zipf’s Power Law and Manifestation of Fractional Differential Equation for Capacitor 被引量:1
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作者 Shantanu Das 《Journal of Modern Physics》 2017年第12期1988-2012,共25页
The classical power law relaxation, i.e. relaxation of current with inverse of power of time for a step-voltage excitation to dielectric—as popularly known as Curie-von Schweidler law is empirically derived and is ob... The classical power law relaxation, i.e. relaxation of current with inverse of power of time for a step-voltage excitation to dielectric—as popularly known as Curie-von Schweidler law is empirically derived and is observed in several relaxation experiments on various dielectrics studies since late 19th Century. This relaxation law is also regarded as “universal-law” for dielectric relaxations;and is also termed as power law. This empirical Curie-von Schewidler relaxation law is then used to derive fractional differential equations describing constituent expression for capacitor. In this paper, we give simple mathematical treatment to derive the distribution of relaxation rates of this Curie-von Schweidler law, and show that the relaxation rate follows Zipf’s power law distribution. We also show the method developed here give Zipfian power law distribution for relaxing time constants. Then we will show however mathematically correct this may be, but physical interpretation from the obtained time constants distribution are contradictory to the Zipfian rate relaxation distribution. In this paper, we develop possible explanation that as to why Zipfian distribution of relaxation rates appears for Curie-von Schweidler Law, and relate this law to time variant rate of relaxation. In this paper, we derive appearance of fractional derivative while using Zipfian power law distribution that gives notion of scale dependent relaxation rate function for Curie-von Schweidler relaxation phenomena. This paper gives analytical approach to get insight of a non-Debye relaxation and gives a new treatment to especially much used empirical Curie-von Schweidler (universal) relaxation law. 展开更多
关键词 Power law RELAXATION RATE distribution FRACTIONAL Derivative FRACTIONAL Integration Curie-Von Schweidler law Time-Constants Laplace INTEGRAL Zipf’s law INTEGRAL Representation Time Dependent RELAXATION RATE Scale Dependent RELAXATION RATE Non-Debye RELAXATION
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An optimized framework for degree distribution in LT codes based on power law
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作者 Asim Muhammad Choi GoangSeog 《Journal of Central South University》 SCIE EI CAS 2013年第10期2693-2699,共7页
LT codes are practical realization of digital fountain codes, which provides the concept of rateless coding. In this scheme, encoded symbols are generated infinitely from k information symbols. Decoder uses only(1+α)... LT codes are practical realization of digital fountain codes, which provides the concept of rateless coding. In this scheme, encoded symbols are generated infinitely from k information symbols. Decoder uses only(1+α)k number of encoded symbols to recover the original information. The degree distribution function in the LT codes helps to generate a random graph also referred as tanner graph. The artifact of tanner graph is responsible for computational complexity and overhead in the LT codes. Intuitively, a well designed degree distribution can be used for an efficient implementation of LT codes. The degree distribution function is studied as a function of power law, and LT codes are classified into two different categories: SFLT and RLT codes. Also, two different degree distributions are proposed and analyzed for SFLT codes which guarantee optimal performance in terms of computational complexity and overhead. 展开更多
关键词 FOUNTAIN CODES DEGREE distribution OVERHEAD computational COMPLEXITY power law
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Power Law Distributions in the Experiment for Adjustment of the Ion Source of the NBI System
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作者 韩筱璞 胡纯栋 《Plasma Science and Technology》 SCIE EI CAS CSCD 2005年第6期3102-3104,共3页
The experiential adjustment process in an experiment on the ion source of the neutral beam injector system for the HT-7 Tokamak is reported in this paper. With regard to the data obtained in the same condition, in arr... The experiential adjustment process in an experiment on the ion source of the neutral beam injector system for the HT-7 Tokamak is reported in this paper. With regard to the data obtained in the same condition, in arranging the arc current intensities of every shot with a decay rank, the distributions of the arc current intensity correspond to the power laws, and the distribution obtained in the condition with the cryo-pump corresponds to the double Pareto distribution. Using the similar study method, the distributions of the arc duration are close to the power laws too. These power law distributions are formed rather naturally instead of being the results of purposeful seeking. 展开更多
关键词 power law distribution adjustment experiment ion source double Pareto distribution
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Fracture propagation law of temporary plugging and diversion fracturing in shale reservoirs under completion experiments of horizontal well with multi-cluster sand jetting perforation
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作者 ZOU Yushi LI Yanchao +3 位作者 YANG Can ZHANG Shicheng MA Xinfang ZOU Longqing 《Petroleum Exploration and Development》 SCIE 2024年第3期715-726,共12页
This study conducted temporary plugging and diversion fracturing(TPDF)experiments using a true triaxial fracturing simulation system within a laboratory setting that replicated a lab-based horizontal well completion w... This study conducted temporary plugging and diversion fracturing(TPDF)experiments using a true triaxial fracturing simulation system within a laboratory setting that replicated a lab-based horizontal well completion with multi-cluster sand jetting perforation.The effects of temporary plugging agent(TPA)particle size,TPA concentration,single-cluster perforation number and cluster number on plugging pressure,multi-fracture diversion pattern and distribution of TPAs were investigated.A combination of TPAs with small particle sizes within the fracture and large particle sizes within the segment is conducive to increasing the plugging pressure and promoting the diversion of multi-fractures.The addition of fibers can quickly achieve ultra-high pressure,but it may lead to longitudinal fractures extending along the wellbore.The temporary plugging peak pressure increases with an increase in the concentration of the TPA,reaching a peak at a certain concentration,and further increases do not significantly improve the temporary plugging peak pressure.The breaking pressure and temporary plugging peak pressure show a decreasing trend with an increase in single-cluster perforation number.A lower number of single-cluster perforations is beneficial for increasing the breaking pressure and temporary plugging peak pressure,and it has a more significant control on the propagation of multi-cluster fractures.A lower number of clusters is not conducive to increasing the total number and complexity of artificial fractures,while a higher number of clusters makes it difficult to achieve effective plugging.The TPAs within the fracture is mainly concentrated in the complex fracture areas,especially at the intersections of fractures.Meanwhile,the TPAs within the segment are primarily distributed near the perforation cluster apertures which initiated complex fractures. 展开更多
关键词 shale temporary plugging and diversion fracturing multi-cluster sand jetting perforation distribution of temporary plugging agent fracture propagation law
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Power-law Distribution of Normal Fault Displacement and Length and Estimation of Extensional Strain due to Normal Faults:A Case Study of the Sierra de San Miguelito, Mexico 被引量:1
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作者 XUShunshan A.F.NIETO-SAMANIEGO S.A.ALANIZ-ALVAREZ 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2005年第1期36-42,共7页
The Sierra de San Miguelito is a relatively uplifted area and is constituted by a large amount of silicic volcanic rocks with ages from middle to late Cenozoic. The normal faults of the Sierra de San Miguelito are Dom... The Sierra de San Miguelito is a relatively uplifted area and is constituted by a large amount of silicic volcanic rocks with ages from middle to late Cenozoic. The normal faults of the Sierra de San Miguelito are Domino-style and nearly parallel. The cumulative length and displacement of the faults obey power-law distribution. The fractal dimension of the fault traces is -1.49. Using the multi-line one-dimensional sampling, the calculated exponent of cumulative fault displacements is -0.66. A cumulative curve combining measurements of all four sections yielded a slope of -0.63. The displacement-length plot shows a non-linear relationship and large dispersion of data. The large dispersion in the plot is mainly due to the fault linkage during faulting. An estimation of extensional strain due to the normal faults is ca. 0.1830. The bed extension strain is always less than or equal to the horizontal extension strain. The deformation in the Sierra de San Miguelito occurred near the surface, producing pervasive faults and many faults are too small to appear in maps and sections at common scales. The stretching produced by small faults reach ca. 33% of the total horizontal elongation. 展开更多
关键词 power-law distribution normal faults small faults finite strain Mexico
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