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Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ObjectiveThis paper aims to analyzes the shock response characteristics of a large-scale floating shock platform (LFSP) subjected to underwater explosion. MethodsThe acoustic-solid coupling approach is used as the basis for the numerical simulation. The validity of the calculation method used in this paper is verified by comparing the experimental data with simulation, and the shock response characteristics of the location of interest in the LFSP's inner bottm plating is investigated in terms of its longitudinal section distribution as well as the effects of changes in the horizontal distance to the blast source on the whole shock environment of LFSP's inner bottom structure, thereby the LFSP's shock response prediction formula is obtained by fitting method.ResultsThe results indicate that the shock response characteristics of the locations (i.e. outer and inner plates, longitudinal section in centre plane) distributed along the longitudinal section of the inner bottom structure are basically the same. The shock response amplitude of the front and back sides of the floating platform are small, while that of the middle is large. The shock responses of the outer and inner plates differ, and the spectral velocity of the inner plate is greater than that of the outer plate, while the spectral displacement of the outer plate is greater than that of the inner plate.ConclusionsThe measurement points within the inner bottom plating are excited so spikes appear in the shock spectral lines, resulting in the spectral velocity of the inner plate is higher than that of the outer plate. The horizontal distance of bottom plate to the blast source is smaller so the shock response is stronger, bringing about a greater spectral displacement of the outer plate than that of the inner plate.

Copyright of Arid Land Geography is the property of Chinese Academy of Sciences, Xinjiang Institute of Ecology & Geography and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Shanghai Land & Resources / Shanghai Guotu Ziyuan is the property of Editorial Board of Shanghai Land & Resources and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Asian Journals of Ecotoxicology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Advances in Earth Science (1001-8166) is the property of Advances in Earth Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Environmental Science & Technology (10036504) is the property of Editorial Board of Environmental Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Nonferrous Metals (Mining Section) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Engineering Geology / Gongcheng Dizhi Xuebao is the property of Journal of Engineering Geology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper analyzes 4 153 traditional villages in China, and uses GIS and other spatial analysis methods to deeply analyze the distribution characteristics of traditional villages and their formation mechanisms. The research finds that: (1) The distribution of traditional villages in China is generally condensed, mainly in the eastern coastal and southwestern regions, but the causes of the two are significantly different. (2) With the change of historical periods, the spatial agglomeration form of traditional villages has changed from "single core, multiple cores" to "multiple cores, single core". The number of traditional villages in the eastern agricultural and cultural area is significantly higher than that in the western nomadic cultural area. The distribution of traditional villages in the southwestern minority agricultural and cultural sub-region is the most concentrated. The distribution of ethnic minority traditional villages is in the middle of the southwest region, and the Han traditional villages are distributed in the south of the middle reaches of the Yangtze River. (3) The formation of the distribution pattern of traditional villages is the result of the comprehensive effect of many factors. Topography, climate, precipitation, and river waters are the basic factors that determine the formation and continuation of traditional villages. Agricultural production methods and historical population migration affect the agglomeration and development of traditional villages. The key factors of the sustainable development of traditional villages are the total number of existing traditional villages and the protection of local government policies. [ABSTRACT FROM AUTHOR]

This paper is based on the place names of Yanbian in China and Hamgyǒngbuk-do in North Korea which both in the Changbai Mountain area. Firstly, the classification and character analysis of the place names in the two regions is carried out, and the results show that the place names in Yanbian and Hamgyǒngbuk-do have regular similarity and differentiation in the type distribution and character characteristics. Based on spatial visualization, the kernel density estimation, direction distribution, elevation distribution, and spatial autocorrelation of place names in the two regions are analyzed. The results show that the place names of the two regions are not evenly distributed in space, and there are many dense areas. The place names are clustered in the eastern coastal areas of Hamgyǒngbuk-do and the areas on both sides of the China- North Korea border. The place names in the two regions are mostly concentrated on hills, terraces, and other topography. The place names of Yanbian and Hamgyǒngbuk-do spread along the direction of northwest-southeast and northeast-southwest, respectively, which are positively correlated with the altitude. The place names of Yanbian are more discrete than those of Hamgyǒngbuk- do, and the correlation between place names of Hamgyǒngbuk-do and altitude is greater than those of Yanbian. Yanbian presents high-value aggregation while Hamgyǒngbuk-do presents low-value aggregation. It reveals that the place-name distribution characteristics objectively implicitly or explicitly reflect the natural environment in different areas of the border between China and North Korea, and the unique place-name culture in the Changbai Mountain area is historical and national. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Geological Hazard & Control is the property of China Institute of Geological Environmental Monitoring (CIGEM) Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Problems concerning accumulation, degradation, metabolites and source identification of PAHs (polycyclic aromatic hydrocarbons) in lake ecosystems are hot topics of environmental protection in China. It is of great significance for restoration of the impaired lake ecosystems to carry out investigations concerning PAHs pollution status, the development trends, distribution characteristics, ecological risks and the sources apportionment in lakes of different areas in China. Based on the literature reviews in this respect, the paper indicated that (1) Most lakes had been at or above moderate pollution level (89%) in China, and 49% of lakes were heavily and severely polluted by PAHs. (2) Lakes, among others, in the eastern plain area accounted for 67%. (3) In terms of the characteristics of individual PAHs distribution in lake sediments, the high molecular weight PAHs predominated in the eastern area, while in Yunnan-Guizhou Plateau, Mongolia-Xinjiang and Qinghai-Tibet Plateau lakes, PAHs were of lower molecular weights. (4) Since China began reform and opening up, especially during the period of 1980-1990s, PAHs concentrations in lake sediments have been on the rise. (5) With respect to the source apportionment methods, the mostly commonly used at present are the diagnosis ratio and principal component analysis; besides, it is appropriate to use the PMF model when performing quantitative source apportionment. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on the monitoring data of PM2.5 obtained from national control stations during 2015-2018, this paper analyzes the annual change trend of PM2.5 concentration in different regions of Anhui Province, among which the PM2.5 concentration in the middle areas is the largest, followed by the south areas, and the PM2.5 concentration in the north areas is relatively small, indicating the pressure for improving the ambient air quality is large. Analysis of PM2.5 concentration distribution in January 2015-2018 and the backward trajectory of pollution sources indicate that the upper reaches of the air flow track in the north areas of the Province are generally the areas with higher pollution degree, while the air flow track sources in the middle and south areas are relatively scattered. Through emission reduction test simulated by WRF-NAQPMS regional model, the contribution rate of endogenous source to the concentration of PM2.5 in the whole province is 29%, while the contribution rate of endogenous source in the north of the Province is 23%. The results show that the contribution rate of endogenous source to the north of Anhui Province is lower than the average, and the contribution of exogenous transport to the north areas is higher than other regions. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Pearl River is the property of Pearl River Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agricultural Resources & Environment / Nongye Ziyuan yu Huanjing Xuebao is the property of Journal of Agricultural Resources & Environment Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Pearl River is the property of Pearl River Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To deeply understand the quantity, quality, spatial distribution characteristics and the representative of cultivated land of national standard farmland in western China at macro scale, it is very important to set up and improve the monitoring system of cultivated land quality in the whole country. This paper, based on the database of farmland classification and national standard farmland in western China (12 provinces, municipalities and autonomous regions), gives a analysis of the quantitative distribution characteristic of national standard farmland of the western region in gradation (quality) and on a secondary zone of the standard farming system. The paper then analyzes the spatial distribution features of standard farmland based on GIS and conducts inspection, definition and statistical tests for the representative of national standard farmland. Results show that: (1) In the view of quantitative distribution characteristics, national standard farmlands of the western China were distributed across all the gradations 4-15, but exhibited great differences in each gradation, such as more than half of them concentrated in 8-12 gradation. The distribution of national standard farmland in the 4, 5, 14, and 15 grades was less. Furthermore, national standard farmlands of the western China are unevenly distributed in the secondary zone and have not covered 28 secondary zones of the standard farming system. Therefore, there exists cultivated land but no national standard farmland in five secondary zones such as Daxing'an Mountains region and so on. (2) From the spatial distribution characteristics, national standard farmland is uniformly distributed on the whole, but there is a significant spatial difference and there exist excessive concentration phenomena in six secondary zones. Thus, the data presented suggest that we should adjust and optimize the monitoring sample plot layout of national standard farmland in western China, according to a comprehensive analysis of the testing results and the distribution characteristics. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Hydrobiology is the property of Editorial Department of Journal of Hydrobiology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agricultural Science & Technology (1008-0864) is the property of Journal of Agricultural Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Remote Sensing for Natural Resources is the property of Remote Sensing for Natural Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To improve the research and evaluation effect of remaining oil in high water cut oilfields， this paper sorted out the concept and influencing factors of remaining oil， summarized the research methods and applicable conditions of remaining oil from three aspects of microscopic distribution， macroscopic distribution， and quantitative analysis of saturation of remaining oil， and discussed the distribution characteristics of remaining oil in water flooding reservoirs， heavy oil reservoirs， and chemical flooding reservoirs based on literature research. The difficulties and development trends of remaining oil research were further put forward. The results show that the influencing factors of remaining oil mainly include geological structure， sedimentary microfacies， reservoir heterogeneity， well pattern density， well pattern， perfection of injection-production system， and production performance. The remaining oil research methods include experimental analysis， numerical simulation， field testing， etc. The research purposes and applicable conditions of each method are different， and the test results reflect the distribution of remaining oil saturation at different locations and scales. The distribution of remaining oil in high water cut oilfields is highly dispersed and relatively enriched， and the microscopic distribution of remaining oil is in various forms of continuous and discontinuous phases. The development trend of remaining oil research includes but is not limited to five aspects： the construction of super-large physical models， the integration of multi-scale high-resolution imaging systems， the improvement of numerical simulation methods considering the time-varying and discontinuous nonlinear seepage of different displacement media and physical properties， the comprehensive application of multidisciplinary and multi-method field testing， and the wide application of big data artificial intelligence.

Copyright of Rock & Mineral Analysis is the property of Editorial Board of Rock & Mineral Analysis and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of the Chinese Society of Rare Earths is the property of Editorial Department of Journal of the Chinese Society of Rare Earths and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Support vector machine (SVM) is one of the most popular classification methods and widely used in practice. But with the development of application, it encounters a problem which seriously limits the classification efficiency: it only focuses on the margin between classes, but ignores the class distributions. In order to solve the above problem, this paper proposed minimum class variance support vector machine (MCVSVM) by Zafeiriou and considered boundary information and distribution characteristics and therefore its classification efficiency was much better than SVM. The local characteristics of each class was quite important but it was regrettable that it was neglected by both SVM and MCVSVM. In view of this, this paper proposed support vector machine based on minimum manifold-based within-class scatter ( SVM-M WCS). The theoretical and experimental analysis shows the effectiveness of our proposed methods. [ABSTRACT FROM AUTHOR]

【Objective】 The present paper aimed to find out the soil nutrients characteristics of spatial distribution in the roots of Haloxylon ammodendron in the southern margin of the Gurbantunggut Desert.【Method】The 149-Regimen,Ganjiahu Nature Reserve and the H.ammodendron in the desert area around the Karamay Agricultural Technology Development Zone were taken as examples,The spatial distribution and characteristics of pH,electrical conductivity,water content,organic matter and available phosphorus in the roots of H.ammodendron were quantitatively studied by a combination of field survey sampling and laboratory test analysis.【Result】In different areas,the soil water content and soil pH of the root ofH.ammodendron were mainly near the main root the middle of the crown>the edge of the crown,and the difference was significant(P <0.05); The organic matter content decreased with the depth of the soil layer; The soil available phosphorus content and the soil electrical conductivity were generally in the middle of the crown > near the main root > the crown edge,which generally decreases with the increase of soil depth.【Conclusion】There was a ‘fat island’ effect in the root zone of H.ammodendron in different regions,and the maximum concentration range in 0-40 cm soil layer. [ABSTRACT FROM AUTHOR]

【Objective】The present paper aimed to provide theoretical basis for the rational application of potassium and chlorine fertilizer in the flue-cured tobacco production in Yunnan raw material base of Yunyan brand.【Method】 1130 soil samples from 37 counties of Kunming, Qujing, Honghe, Baoshan, Wenshan were used as materials to determine the content of potassium and chlorine in tobacco samples. The characteristics of potassium and chlorine ratio in different regions, main varieties, soils at different altitudes and tobacco leaves in Yunnan raw material base of Yunyan brand were analyzed. The potassium chlorine ratio of tobacco leaves was regionalized by ArcGIS. 【Result】The results showed that the samples with potassium chloride ratio more than 10 % were the most, accounting for 43.2 %; The samples with potassium chloride ratio between 4.0 % and 6.0 % were the least, accounting for 11.7 %. Qujing had the largest number of towns with low K/C ratio(< 4 %) and Wenshan had the smallest; Qujing had the largest number of towns with high K/C ratio(> 10 %), while other cities had the same number. The main cultivar with the highest mean of K/C ratio in middle tobacco leaves was Yunyan 85, which was 14.41; The lowest was Yunyan 97, which was 7.30; The others were between 8.44 and 12.73. The highest mean of K/C ratio of middle tobacco leaves in different altitude areas was 11.72, which was mainly distributed in the altitude area of 1100-1400 meters; The lowest was 8.91, which was mainly distributed in the altitude area of 2000-2300 meters. 【Conclusion】In order to production of high-quality flue-cured tobacco in Yunnan raw material base of Yunyan brand, areas with high K/C ratio of tobacco leaves in Kunming, Qujing, Honghe, Baoshan and Wenshan could be selected. K326, Yunyan 87, Yunyan 85 and other high efficient flue-cured tobacco varieties for potassium accumulation and utilization could be selected. It could be planted at the altitude of 1100-2000 meters. [ABSTRACT FROM AUTHOR]

Copyright of Acta Sedimentologica Sinica is the property of Acta Sedimentologica Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Engineering Geology / Gongcheng Dizhi Xuebao is the property of Journal of Engineering Geology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agricultural Science & Technology (1008-0864) is the property of Journal of Agricultural Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to understand the heavy metal pollution in surrounding farmland tillage soil caused by coal mine, this paper studied the area around a coal mine in southwest Shandong province. The 104 samples of surrounding farmland tillage soil were collected, and the concentration of heavy metals including Cr, Ni, Cu, Cd, Zn, Pb were tested by ICP-MS. Single factor index, nemero index and geoaccumulation index were used to analyze the spatial distribution characteristics and the appraise pollution level of six heavy metals. The results show that the six kinds of heavy metals are obviously accumulated, and have different spatial distribution characteristics in the nearby regions of coal gangue dump, industrial square, coal transfer station and transit lines. Only Cu and Ni elements have significant correlation in spatial distribution. The total pollution is in a light degree. It has no Cr element pollution, small-scale slight pollution area of Ni element, some slight pollution area and small-scale moderately pollution area of Cd element in the research area. Other elements including Cu, Zn and Pb are relatively safe. [ABSTRACT FROM AUTHOR]

This paper describes a new method for determining the individual sources of goaf gas emissions in Shihe coal mine. Desorbed gases from coal seam No. 3 and its seven neighboring seams were respectively sampled and analyzed of iheir composition including CH4 ,C2H6, stable carbon isotopes in CO2 and hydrogen isotopes in CH4. Based on the analyzed results,a mathematical model was developed for calculating the sources of goaf gas emissions. The model was then applied in No. 5302 panel in Shihe coal mine to determine the emission sources of the goaf gas from each of the coal seams. The results show that CH4 concentration, stable carbon isotopes in CO2 and hydrogen isotopes in CH4 in creased with the depth of No. 3 seam. In terms of the characteristics of goaf gas emissions in No. 5302 panel, it can be divided into three stages with the panel advance. In the initial stage,the goaf gas emission was dominated with gas desorbed from the mining No. 3 seam, this dominance weakened as the panel advances and stabilized at around 20% - 25% of the total goaf gas emissions. In the second stage,gas from neighboring seams started to play an important role in the goaf gas,taking up 20%-25% of the total goaf gas emissions. In the third stage,the sources of the goaf gas emission became stable and gases desorbed from No. 9 and No. 15 seams made up 20% -25% and 30% -35% of the total goaf gas emissions respectively. This isotopes based method,in comparison with the tradition method for determining the sources of goaf gas emissions, can give quantitative description of dynamic change in the individual sources of goaf gas emissions with the advance of a mining panel, enabling a more targeted and effective control of goaf gas emissions. [ABSTRACT FROM AUTHOR]

After the coal mining face is mined, the pressure transmitted by the surrounding rock in the goaf will experience a process from growth to stability, during this period, the growth rate and pressure distribution of overburden pressure in goaf have a direct impact on the safety production of working face and the surrounding roadway support. In order to deeply study the overburden pressure distribution characteristics of goaf after push mining in adjacent mining faces, this paper studies the overburden pressure distribution characteristics of goaf in adjacent fully mechanized mining faces through the combination of field data measurement and theoretical analysis, and obtains the distribution law of goaf pressure in strike and dip direction. The results show that: after the overburden pressure of goaf is stable, its tendency overburden pressure presents “□” parabolic distribution, which is specifically expressed as the overburden pressure in the middle of goaf > the overburden pressure in the lower part of goaf > the overburden pressure in the upper part of goaf; the change of overburden pressure in goaf is divided into four stages: initial growth period of pressure value, slow rise period of pressure value, rapid growth period of pressure value and gradual stabilization period of pressure value.

The study of metal element mineral resources in coal is the focus in the field of coal geology,and it has important strategic significance for the transformation of China’ s coal industry. In order to systematically sort out the status quo of mineral resources in China’ s coal,to promote the comprehensive investigation and utilization of mineral resources in coal,to expand the development direction of traditional coal geological industry,In this paper,based on the systematic collection of relevant geological data, sampling test, comprehensive analysis and research, Through the systematic discussion, the concept of mineral resources mineral resources in coal is put forward,the concept of the main metal element mineral resources in coal is put forward,and the distribution characteristics of gallium, germanium and lithium in coal are summarized. By analyzing the source, sedimentary environment and tectonic-thermal evolution conditions, the distribution characteristics of gallium, germanium and lithium resources in China’ s coal. The copper and gallium enrichment areas in China are mainly distributed in the two coal-forming stages of the Carboniferous-Permian and South China Permian in China. The germanium in coal is mainly distributed in the northeast early chalk The control of germanium, gallium and lithium metal in coal is characterized by regional distribution, At the same time, combined with the current coal mineral resources in the forefront of mineral resources research problems, the future research direction of metal element mineral resources in China is prospected. Proposed to focus on strengthening the coal metal element testing technology and enrichment of mineralization mechanism of the study, Which is of guiding significance for the comprehensive development and utilization of mineral resources in China. [ABSTRACT FROM AUTHOR]

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Copyright of Mycosystema is the property of Mycosystema Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the present paper, the authors conducted some experiments on the samples of the soils of Daquanhu coal fire for analyzing the characteristics of the heavy metals distribution in this fire zone, such as the Hg, As, Cu, Pb, Cr and the Zn, which is relevant to the soil properties of the sampling sites. Results show that the temperature increases with the depth increase of the sampling site in both normal and abnormal area, and the variation of temperature increase in the normal area is less than that of the abnormal area. The content of organic matter of soils decreases with the depth increase of the sampling site in both the normal area and the abnormal area. And the layer one, the layer two, the layer three and the layer four of the normal area soil contains more organic matter than that of the abnormal area soils. The contents of some heavy metals in the layer one of normal area soil, such as the Cu, Pb, Cr, Zn and the Ni, are less than that of the layer one of the abnormal soil. In the layer two of the abnormal area soil, the content of these heavy metals shows a trend of increase. In both the normal area and the abnormal area soils, the contents of the Hg, As, Cu and the Ni fluctuate little along the increase of the depth of sampling site. But the contents of the Pb, Cr and the Zn in abnormal area soil fluctuate more than that of the normal area soil. Results also show that the heat effect of the coal fire, the topography of the fire zone, the properties of the soil and the local climate parameters are the main factors to impact the spatial distribution of the heavy metals in the soil of underground coal fires. An analysis of the As speciation shows that the content of the residual As speciation is the highest, and that of the water soluble As speciation is the lowest. Contents contour maps show that the accumulating characteristics of the water soluble As speciation within the soil of the layer one to layer four consequently has the same trend of the accumulation of CaCO3 in this area. In the normal area of the fire zone, the contents of the residual As speciation and the iron As speciation have the same trend of change as the change of CaCO3 following the sampling depth increase. However, in the abnormal area of the fire zone, the content of the residual As fluctuates with a similar trend of the content of the organic matter following the increase of sampling depth. The mean content of the water soluble As in both the normal area and the abnormal area stays stable, which indicates that no close relationship exists between the As content and the soil temperature as well as the soil properties. [ABSTRACT FROM AUTHOR]

In order to effectively manage and protect the shallow groundwater resource in Yongcheng City and maintain the sustainable utilization of water resource, distribution characteristics and sources of pollutants must be identified.On the basis of sampling and analysis of shallow groundwater, this paper studies the sources and distribution characteristics of main pollution components, combining with the influence of industrial layout change and land use type distribution caused by urban development.The results show that the growth of urban secondary industry (industry and mining) and GDP are correlated with the increase of SO42- and NO3- contents in shallow groundwater, the dense areas of urban industry and population tend to be the same as the seriously polluted areas of shallow groundwater.The main source of shallow groundwater pollution is the increase of SO42- content, in addition to directly causing the deterioration of water quality.It also indirectly changes the intensity of hydrogeochemical action.It leads to an increase in the dissolution of the insoluble carbonate and silicate, which further increases the content of TDS and changes the water quality.In addition, NO3- and COD are also the main pollution sources.It comes partly from industrial waste water and partly from the excessive use of pesticides and fertilizer in agriculture.

Based on the data of Ningxia Hui Autonomous Region forest resources inventory, field investigation and laboratory analysis, this paper studied the carbon sequestration status of forest eco-systems in Ningxia region, estimated the carbon density and storage of forest ecosystems, and analyzed their spatial distribution characteristics. The results showed that the biomass of each forest vegetation component was in the order of arbor layer (46. 64 Mg·hm-2 ) > litterfall layer (7. 34 Mg·hm-2) > fine root layer (6. 67 Mg·hm-2 ) > shrub-grass layer (0. 73 Mg·hm-2 ). Spruce (115. 43 Mg·hm-2) and Pinus tabuliformis (94. 55 Mg·hm-2 ) had higher vegetation biomasses per unit area than other tree species. Over-mature forest had the highest arbor carbon density among the forests with different ages. However, the young forest had the highest arbor carbon storage (1. 90 Tg C) due to its widest planted area. Overall, the average carbon density of forest ecosystems in Ningxia region was 265. 74 Mg C·hm-2, and the carbon storage was 43. 54 Tg C. Carbon density and storage of vegetation were 27. 24 Mg C·hm-2 and 4. 46 Tg C, respectively. Carbon storage in the soil was 8. 76 times of that in the vegetation. In the southern part of Ningxia region, the forest carbon storage was higher than in the northern part, where the low C storage was mainly related to the small forest area and young forest age structure. With the improvement of forest age structure and the further implementation of forestry ecoengineering, the forest ecosystems in Ningxia region would achieve a huge carbon sequestration potential. [ABSTRACT FROM AUTHOR]

This paper studied the distribution characteristics of phosphorus contents of 107 flue-cured tobacco leaf samples from domestic main tobacco areas and Zimbabwe, and analyzed the relationships between phosphorus contents and routine chemical components. The results indicated that: CD the phosphorus content of domestic main tobacco areas ranged from 0.25% to 0.66% with the mean of (0.43 ±0.08) %, the phosphorus content of Zimbabwe ranged from 0.45% to 0.67% with the mean of (0.53 ± 0.05) %; (2) the order of the phosphorus contents in flue-cured tobacco leaves among different areas was Zimbabwe (0.53%) > Southeast tobacco area (0.49%) > the upper and middle Yangtze River tobacco area (0.45%) > Southwest tobacco area (0.42%) > the Yellow and Huai River tobacco area (0.41%) > North tobacco area (0.39%), and the differences among these areas reached extremely significant level; (3) the phosphorus contents increased with the rise of stalk position, and there was no significant difference among different positions; (4) the phosphorus content in flue-cured tobacco leaf had significant or extremely significant positive correlation with nicotine, potassium and chlorine contents, and had extremely negative correlation with total sugar, reducing sugar content and nitrogen/nicotine, sugar/nicotine, but had no significant correlation with total nitrogen and potassium/chlorine; (5) the clustering results based on the phosphorus contents and harmonic character evaluation of the chemical components at different phosphorus content levels showed that the flue-cured tobacco leaves with medium and high phosphorus content clusters had proper chemical components, better harmony among indexes and high available value. [ABSTRACT FROM AUTHOR]