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用于大地测量数据的空间大地元数据标准
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作者 Spen.,JF 肖学年 《测绘标准化》 1998年第2期29-35,共7页
联邦地理数据委员会(FGDC)的联邦大地控制测量分委会(FGCS)负责制定适当的标准和规范以用于采集和存储大半测量数据并将这些数据提供给联邦、州和地方政府及私人企业。1994年6月8日颁布FGDC的《数字空间大地元数... 联邦地理数据委员会(FGDC)的联邦大地控制测量分委会(FGCS)负责制定适当的标准和规范以用于采集和存储大半测量数据并将这些数据提供给联邦、州和地方政府及私人企业。1994年6月8日颁布FGDC的《数字空间大地元数据内容标准》,该标准为逐步建立国家空间数据基础设施(NSDI)提供了数字数据交换的机制。 展开更多
关键词 大地测量 测量数据 空间大地元 数据标准
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A Comparative Study of the L2 Pragmatic Competence of University Students in Hong Kong and the Chinese Mainland:The Contributions of Sociocultural Context and Linguistic Proficiency
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作者 Scott AUBREY Rod ELLIS 《Chinese Journal of Applied Linguistics》 2024年第3期371-392,524,共23页
This study investigates the differences in pragmatic competence between Hong Kong and Chinese mainland university students.Participants included 19 native speakers of English,115 Chinese mainland students,divided into... This study investigates the differences in pragmatic competence between Hong Kong and Chinese mainland university students.Participants included 19 native speakers of English,115 Chinese mainland students,divided into those who had spent time abroad in an English-speaking country(CM A)and those who had not(CM NA),and 97 Hong Kong students,divided into those from an English-medium secondary school(Hong Kong EMI)and those from a Chinese-medium school(Hong Kong CMI).Linguistic proficiency was measured by a C-test,and pragmatic competence by a Metapragmatic Knowledge Test,an Irony Test and a Monologic Role Play.Group scores were compared using ANCOVAs to control for differences in proficiency.The results point to a continuum of pragmatic competence—EMI>CMI>CM A>CM NA—reflecting the groups’access to English in real-life contexts.The differences between the Hong Kong groups and the Chinese mainland groups were clearest in those tests measuring processing capacity(i.e.,Irony Response Time and the Monologic Role Play).CM A,but not CM NA,performed as well as the Hong Kong groups on measures of metapragmatic awareness.The results are discussed in terms of Bialystok’s(1993)distinction between analyzed representation and control of processing. 展开更多
关键词 pragmatic competence social context Hong Kong the Chinese mainland metapragmatic knowledge processing capacity
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Rapid detection and risk assessment of soil contamination at lead smelting site based on machine learning
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作者 Sheng-guo XUE Jing-pei FENG +5 位作者 Wen-shun KE Mu LI Kun-yan QIU Chu-xuan LI Chuan WU Lin GUO 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第9期3054-3068,共15页
A general prediction model for seven heavy metals was established using the heavy metal contents of 207soil samples measured by a portable X-ray fluorescence spectrometer(XRF)and six environmental factors as model cor... A general prediction model for seven heavy metals was established using the heavy metal contents of 207soil samples measured by a portable X-ray fluorescence spectrometer(XRF)and six environmental factors as model correction coefficients.The eXtreme Gradient Boosting(XGBoost)model was used to fit the relationship between the content of heavy metals and environment characteristics to evaluate the soil ecological risk of the smelting site.The results demonstrated that the generalized prediction model developed for Pb,Cd,and As was highly accurate with fitted coefficients(R^(2))values of 0.911,0.950,and 0.835,respectively.Topsoil presented the highest ecological risk,and there existed high potential ecological risk at some positions with different depths due to high mobility of Cd.Generally,the application of machine learning significantly increased the accuracy of pXRF measurements,and identified key environmental factors.The adapted potential ecological risk assessment emphasized the need to focus on Pb,Cd,and As in future site remediation efforts. 展开更多
关键词 smelting site potentially toxic elements X-ray fluorescence potential ecological risk machine learning
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Deformation caused by the 2011 eastern Japan great earthquake monitored using the GPS single-epoch precise point positioning technique 被引量:4
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作者 郭金运 原永东 +2 位作者 孔巧丽 李国伟 王方建 《Applied Geophysics》 SCIE CSCD 2012年第4期483-493,497,共12页
Crustal deformation can provide constraints for studying earthquake rupture and shock wave transmission for the Mw9.0 eastern Japan great earthquake. Using the single- epoch precise point positioning (PPP) method an... Crustal deformation can provide constraints for studying earthquake rupture and shock wave transmission for the Mw9.0 eastern Japan great earthquake. Using the single- epoch precise point positioning (PPP) method and the appropriate positioning flow, we process GPS data from six IGS (International GNSS Service) sites (e.g., MIZU, TSK2, USUD, MTKA, AIRA and KSMV) located in Japan and obtain the positioning results with centimeter scale precision. The displacement time series of the six sites are analyzed using the least squares spectral analysis method to estimate deformations caused by the Mw9.0 mainshock and the Mw7.9 aftershock, and the cumulative displacements after 1 day. Mainshock displacements at station MIZU, the nearest site to the mainshock in the North (N), East (E), and Up (U) directions, are -1.202 m, 2.180 m and -0.104 m, respectively, and the cumulative deformations after 1 day are -1.117 m, 2.071 m and -0.072 m, respectively. The displacements at station KSMV, the nearest site to the Mw7.9 aftershock in the N, E and U directions, are -0.032 m, 0.742 m and -0.345 m, respectively. The other sites obviously experienced eastern movements and subsidence. The deformation vectors indicate that the horizontal displacements caused by the earthquake point to the epicenter and rupture. Elastic bounds evidently took place at all sites. The results indicate that the crustal movements and earthquake were part of a megathrust caused by the Pacific Plate sinking under the North American Plate to the northeast of Japan island arc. 展开更多
关键词 Eastern Japan great earthquake GPS single-epoch precise point positioning crustal deformation
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Land Suitability Evaluation of Food Crops in Vulnerably Ecological Area Based Upscalin Method 被引量:4
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作者 何英彬 Luca Ongaro 王毅敏 《Agricultural Science & Technology》 CAS 2009年第6期168-174,共7页
In order to provide some preliminary recommendations for the sustainable use and management of croplands, land suitability evaluation for crops was carried out in Shouyang County which partly locates on the Loess Plat... In order to provide some preliminary recommendations for the sustainable use and management of croplands, land suitability evaluation for crops was carried out in Shouyang County which partly locates on the Loess Plateau suffering severe soil and water erosion and is characterized by ecological vulnerability and semi-arid climate. Here, land suitability for 4 local crops of maize, wheat, sorghum and millet under 2 cultivation senarios of tradition and mechanization was evaluated by a upscaling approach. The upscaling was implemented in a land form hierarchy which was composed of land unit, land facet and land site at 3 spatial levels. The IAO land suitability evaluation model for crops was revised by applying a meteorological revision index. Rresults showed that a polarized phenomenon occurred, which means that the most suitable class (S1) and the most unsuitable class (N2) were predominant in acreage percentage for all the 4 crops. Maize, millet and wheat were relatively more adaptive to be grown and should be ploughed in the traditional mode. Hence, future cropland use policy should pay more attention to the conversion of arable land to forestland and grassland in unsuitable areas and to more investment for agricultural production in suitable regions, and it is necessary to balance the relationship between the livelihood of local farmers and environmental protection to maintain a healthy and stable ecosystem. 展开更多
关键词 Land facet Land site Land unit
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CALCULATION METHOD FOR EARTH PRESSURE CONSIDERING DISPLACEMENT 被引量:1
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作者 张小平 胡明亮 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2009年第3期229-234,共6页
The calculation of earth pressure is a difficult problem in the pit foundation design. Aiming at the problem, the earth pressure calculation formulas considering the displacement are proposed. A method for determining... The calculation of earth pressure is a difficult problem in the pit foundation design. Aiming at the problem, the earth pressure calculation formulas considering the displacement are proposed. A method for determining the limit displacement is given and it is convenient for use. The result indicates that the earth pressure calculated by the formulas is between the earth pressure at rest and the Rankine earth pressure, the formulas can reflect the change rules of active and passive earth pressures along with the displacement. Moreover, the calculation result using the formulas is approximate to the monitoring result. It confirms the validity of the formula deduction and the rationality of the calculation results. As for the passive earth pressure, the calculation method is theoretically feasible. 展开更多
关键词 FOUNDATIONS finite element method DISPLACEMENT earth pressure
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Exploration of the spatial pattern of urban residential land use with geographically weighted regression technique: a case study of Nanjing,China 被引量:1
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作者 胡明星 吴江 朱选 《Journal of Southeast University(English Edition)》 EI CAS 2015年第1期149-156,共8页
As the traditional methods and technical means cannot meet the quantitative research needs of the urban land use patterns, quantitative research methods for the urban land use pattern are established via the GIS (geo... As the traditional methods and technical means cannot meet the quantitative research needs of the urban land use patterns, quantitative research methods for the urban land use pattern are established via the GIS (geographic information system ) technique combined with the related theories and models. Taking the city of Nanjing as an example, a spatial database of urban land use and other environmental and socio-economic data is constructed. A multiple linear regression model is developed to determine the statistically significant factors affecting the residential land use distributions. To explain the spatial variations of urban land use patterns, the geographically weighted regression (GWR) is employed to establish spatial associations between these significant factors and the distribution of urban residential land use. The results demonstrate that the GWR can provide an effective approach to the exploration of the urban land use spatial patterns and also provide useful spatial information for planning residential development and other types of urban land use. 展开更多
关键词 urban residential land use GIS (geographic information system) multiple linear regression geographically weighted regression
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The Gaoyuzhuang Palaeobiology 被引量:1
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作者 徐兆良 阿拉米克S.M. 《Acta Botanica Sinica》 CSCD 2002年第5期617-627,共11页
Black bedded, nodular, and lenticular chert and silicified parts of stromatolites from the approximately 1 400 - 1 600 million year-old Gaoyuzhuang Formation, North China, contain remark-ably well prep served microflo... Black bedded, nodular, and lenticular chert and silicified parts of stromatolites from the approximately 1 400 - 1 600 million year-old Gaoyuzhuang Formation, North China, contain remark-ably well prep served microflora composed of diverse prokaryotic and possible eukaryotic microbes. Macroscopic algae have also been found. This Formation provides important paleobiological information from which to assess status of Mesoproterozoic life, and to evaluate paleoenvironmental conditions and pre-Phanerozoic biostratigraphy. The Gaoyuzhuang Formation has yielded over 100 taxa described by over 10 investigators. Most of the microbial taxa can be divided into three different assemblages according to their paleobiological and paleoenvironmental characteristics. I. The oscillatoriacean/chroococcacean assemblage which occurs in the first member of the Formation and this is interpreted to represent an assemblage from shallow water mat-building and mat-dwelling taxa with some possible planktonic taxa; 2. the nostocacean assemblage found only in the second member, and includes benthic mat-building or mat-dwelling taxa; and 3. the chroococcacean assemblage of the fourth member, which represents intertidal to supratidal mat-building and allochthonous taxa. Proterozoic microfossils found in chert, especially cyanobacteria, are possibly more valuable as paleoenvironmental indicators than as chronostratigraphic tools because of their morphological conservation, although trends in diversity appear to exist for cyanobacteria in the Proterozoic. The general characteristics of Gaoyuzhuang microfossils, and the fact that most nostocacean chains occur and are. preserved with the chain perpendicular to bedding indicate that: (1) the individual size of Gaoyuzhuang microfossils are part of a general trend of increase with time; (2) Gaoyuzhuang deposits are possibly in a fresh water environment and the rate of sedimentation might be equal to or less than the microbial growth rate; (3) the sedimentary model of Gaoyuzhuang might be from intertidal to subtidal or deep sea, and then to intertidal or supratidal; and (4) the eukaryotic organisms had densely occurred when Gaoyuzhuang Formation deposited. 展开更多
关键词 North China MESOPROTEROZOIC Gaoyuzhuang Formation PALAEOBIOLOGY
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Analysis on Chemical Compositions in Chinese Wolfberry from Different Producing Areas 被引量:4
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作者 董海峰 任永丽 《Agricultural Science & Technology》 CAS 2012年第9期1870-1872,共3页
[Objective] This study aimed to conduct correspondence cluster analysis of the trace elements in Chinese wolfberry from Qinghai and Ningxia regions, and to investigate the relationship among the quality of the wolfber... [Objective] This study aimed to conduct correspondence cluster analysis of the trace elements in Chinese wolfberry from Qinghai and Ningxia regions, and to investigate the relationship among the quality of the wolfberry samples, the composition of trace elements and the sample sources. [Method] The determined contents of trace elements and ratios of zinc to copper (Zn/Cu) of wolfberry from 11 different producing areas of Qinghai and Ningxia regions were adopted to construct the raw measurement data matrix, to analyze the distribution characteristics of the trace ele- ments in wolfberry from Qinghai and Ningxia by using the corresponding cluster analysis method. [Result] The quality of wolfberry samples in 7hongning County, Zhongwei City, Pingluo County, Shizuishan City, Heicheng Town of Ningxia Hui Au-tonomous Region and Hehuang Valley, Golmud City of Qinghai Province is mainly related to the contents of Zn and Mn; Zn/Cu greatly affects the quality of Chinese wolfberry in Dulan County of Qinghai Province; Fe has great effect on the quality of Chinese wolfberry in Yinchuan City of Ningxia Hui Autonomous Region; Cu greatly affects the quality of Chinese wolfberry in Nuomuhong Village of Qinghai Province and a wolfberry research institute in Ningxia. [Conclusion] The relationship between the quality of wolfberry from different producing areas and the trace elements was investigated, which provides theoretical and practical basis for the cultivation, har- vesting, processing, and further development and utilization of Chinese wolfberry resources from different producing areas. 展开更多
关键词 Chinese wolfberry Correspondence cluster analysis Trace elements
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Wavy Distribution of Trace Elements in Phytolacca Samples from Different Areas 被引量:4
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作者 杜莹 欧阳荔 +1 位作者 刘雅琼 王京宇 《Journal of Chinese Pharmaceutical Sciences》 CAS 2004年第4期271-275,共5页
To study the distribution of 25 elements, i.e. Be, Cd, Ce, Cr, Cu, Dy, Er,Eu, Gd, Ge, Ho, La, Lu, Mo, Nd, Pb, Pr, Sm, Sr, Tb, Tl, Tm, Y, Yb and Zn in Phytolacca, atraditional Chinese medicinal herb, collected from nin... To study the distribution of 25 elements, i.e. Be, Cd, Ce, Cr, Cu, Dy, Er,Eu, Gd, Ge, Ho, La, Lu, Mo, Nd, Pb, Pr, Sm, Sr, Tb, Tl, Tm, Y, Yb and Zn in Phytolacca, atraditional Chinese medicinal herb, collected from nine areas of P. R. China. Methods Twenty-fiveelements in Phytolacca including essential elements, toxic elements and rare earth elements intraditional Chinese medicinal herbs from different areas were analyzed by ICP-MS. Results The 25elements in Phytolacca were determined by ICP-MS under optimized conditions. The detection limitswere 0.003 -0.71 ng·mL^(-1). The recoveries were 88% - 118% . The relative standard deviations ofthe measurements were 1.7% - 13.3%. Conclusion The determined concentrations of elements inPhytolacca acinosa Roxb vary from one area to another; however, the distribution tendency ofelements in all the samples is similar. The distribution tendency of rare earth elements inPhytolacca acinosa Roxb is consistent with that in nature. 展开更多
关键词 traditional chinese medicinal herbs trace elements ICP-MS DISTRIBUTION
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Influence of Soil Geochemistry to the Quality of Winter Jujube in Zhanhua 被引量:1
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作者 高宗军 王敏 +1 位作者 庞绪贵 刘中业 《Agricultural Science & Technology》 CAS 2010年第9期209-212,216,共5页
[Objective] The aim was to investigate the effects of soil geochemistry on the quality of winter jujube.[Method]Based on the data of ecological geochemical survey in lower Yellow River Basin,the relevance of the geoch... [Objective] The aim was to investigate the effects of soil geochemistry on the quality of winter jujube.[Method]Based on the data of ecological geochemical survey in lower Yellow River Basin,the relevance of the geochemistry environment in top soils and the quality of winter jujubes was analyzed.[Result]Cd,Ni and other heavy metals in the soil more obviously affected the nutrition of winter jujubes.[Conclusion]B,Mn,MgO,Cd,Zn,K2O and other elements in the root soil played an important role in the enrichment of Cr and Hg of winter jujube fruit.And the absorption of heavy metals in winter jujube root could be interfered by improving fertilization method,to reduce the enrichment of harmful elements in jujube fruit. 展开更多
关键词 Zhanhua winter jujube Ecological geochemical environment Heavy metal element
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浅谈哈萨克医药(三)
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作者 海拉提·哈力毛拉 《家庭中医药》 2010年第3期16-16,共1页
吐热阿克,即地元(意译:地、立足点、定居点、支柱),泛指人、万物及宇宙立足的本源。它是人类先天禀赋与后天摄生(衣、食、住、行)的源泉,也是寝休的最基本支撑。它以人类及动物、植物、金属、土、砂与石头等支撑来发挥其特性与... 吐热阿克,即地元(意译:地、立足点、定居点、支柱),泛指人、万物及宇宙立足的本源。它是人类先天禀赋与后天摄生(衣、食、住、行)的源泉,也是寝休的最基本支撑。它以人类及动物、植物、金属、土、砂与石头等支撑来发挥其特性与本能。地元给予人类以下的财富(之本):先天的特征、形态、个卟生、性别、差异等及后天养生的立足点、定居点和住宅。 展开更多
关键词 哈萨克医药 先天禀赋 人类 地元 定居 后天
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浅析城市化进程中房地产业的发展——以土地为视角
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作者 王晓夺 《轻工设计》 2011年第1期95-96,共2页
城市化是中国发展的必然趋势,房地产业在城市化发展的进程中又扮演着十分主妥的角色。从二者之间的联系纽带--土地入手,探讨二者之间的联系与互动也就显得极为关键。尤其是在中国城乡二元结构体系下,关于土地的核心问题如果视而不见... 城市化是中国发展的必然趋势,房地产业在城市化发展的进程中又扮演着十分主妥的角色。从二者之间的联系纽带--土地入手,探讨二者之间的联系与互动也就显得极为关键。尤其是在中国城乡二元结构体系下,关于土地的核心问题如果视而不见,城市化与房地产业也许很难有和谐长远的发展。 展开更多
关键词 城市化 地产 地元结构
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Study on Trace Elements in Rehmannia glutinosa Libosch. by Principal Component Analysis and Clustering Analysis
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作者 申明金 陈丽 曹洪斌 《Agricultural Science & Technology》 CAS 2013年第12期1764-1768,共5页
[Objective] This study aimed to investigate the trace elements in Rehman- nia glutinosa Libosch. by using principal component analysis and clustering analysis. [Method] Principal component analysis and clustering anal... [Objective] This study aimed to investigate the trace elements in Rehman- nia glutinosa Libosch. by using principal component analysis and clustering analysis. [Method] Principal component analysis and clustering analysis of R. glutinosa medicinal materials from different sources were conducted with contents of six trace elements as indices. [Result] The principal component analysis could comprehen- sively evaluate the quality of R. glutinosa samples with objective results which was consistent with the results of clustering analysis. [Conclusion] Principal component analysis and clustering analysis methods can be used for the quality evaluation of Chinese medicinal materials with multiple indices. 展开更多
关键词 Rehmannia glutinosa Libosch. (Radix Rehmanniae) Trace elements Principal component analysis Clustering analysis
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Preliminary Study on the Accumulation Characteristics of Mineral Elements in Potted Poa crymophila under Drought and Water Stress
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作者 李天才 曹广民 +2 位作者 林丽 李以康 柯浔 《Agricultural Science & Technology》 CAS 2017年第12期2216-2218,共3页
[Objective] This study was conducted to explain the mechanism of the accumulation characteristics of mineral elements in alpine grassland plants. [Method] Cultivated alpine grassland plant, Poa crymophila, was treated... [Objective] This study was conducted to explain the mechanism of the accumulation characteristics of mineral elements in alpine grassland plants. [Method] Cultivated alpine grassland plant, Poa crymophila, was treated with drought and wa- ter stress, and then the samples were collected and analyzed. [Result] Compared with the control group, under drought and water stress, multiple mineral elements tended to accumulate and increase, and there were significant differences in the contents of Cu, Mn, Ni and P (P〈0.05). [Conclusion] Under drought and water stress, mineral elements in potted Poa crymophila tended to accumulate and in- crease, which is the adaption and response of Poa crymophila to drought and water stress, as well as the re-verification of the starvation effect hypothesis of mineral effects. The starvation effect of mineral elements is one of the endogenic forces for the accumulation and differentiation of mineral elements in grassland plants. 展开更多
关键词 Potted Poa crymophila Mineral elements Accumulation characteristic Drouaht: Water stress
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Two-dimensional frequency-domain acoustic fullwaveform inversion with rugged topography 被引量:1
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作者 张钱江 戴世坤 +3 位作者 陈龙伟 李昆 赵东东 黄兴兴 《Applied Geophysics》 SCIE CSCD 2015年第3期378-388,467,468,共13页
We studied finite-element-method-based two-dimensional frequency-domain acoustic FWI under rugged topography conditions. The exponential attenuation boundary condition suitable for rugged topography is proposed to sol... We studied finite-element-method-based two-dimensional frequency-domain acoustic FWI under rugged topography conditions. The exponential attenuation boundary condition suitable for rugged topography is proposed to solve the cutoff botmdary problem as well as to consider the requirement of using the same subdivision grid in joint multifrequency inversion. The proposed method introduces the attenuation factor, and by adjusting it, acoustic waves are sufficiently attenuated in the attenuation layer to minimize the cutoff boundary effect. Based on the law of exponential attenuation, expressions for computing the attenuation factor and the thickness of attenuation layers are derived for different frequencies. In multifrequency-domain FWI, the conjugate gradient method is used to solve equations in the Gauss-Newton algorithm and thus minimize the computation cost in calculating the Hessian matrix. In addition, the effect of initial model selection and frequency combination on FWI is analyzed. Examples using numerical simulations and FWI calculations are used to verify the efficiency of the proposed method. 展开更多
关键词 Full-waveform inversion rugged topography attenuation boundary condition finite element method
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0.18μm CMOS programmable frequency divider design for DVB-T
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作者 胡庆生 仲建锋 何小虎 《Journal of Southeast University(English Edition)》 EI CAS 2008年第2期159-162,共4页
The implementation of a programmable frequency divider, which is one of the components of the phase-locked loop (PLL) frequency synthesizer for digital video broadcastingterrestrial (DVB-T) and other modem communi... The implementation of a programmable frequency divider, which is one of the components of the phase-locked loop (PLL) frequency synthesizer for digital video broadcastingterrestrial (DVB-T) and other modem communication systems, is presented. By cooperating with a dual-modulus prescaler, this divider can realize an integer frequency division from 926 to 1 387. Besides the traditional standard cell design flow, such as logic synthesis, placement and routing, the interactions between front-end and back-end are also considered to optimize the design flow under deep submicron technology. By back-annotating the back-end information to front-end design, a custom wire-load model is created which is more practical compared with the default model. This divider has been fabricated in TSMC 0. 18μm CMOS technology using Artisan standard cell library. The chip area is 675 μm × 475 μm and the power consumption is about 2 mW under a 1.8 V power supply. Measurement results show that it works correctly and can realize a frequency division with high precision. 展开更多
关键词 programmable frequency divider frequency synthesizer standard cell DVB-T
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Hybrid FEM-BEM for simulation of electromagnetic response
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作者 余海涛 《Journal of Southeast University(English Edition)》 EI CAS 2004年第3期303-308,共6页
A finite element method with boundary element method (FEM-BEM) is presented for computing electromagnetic induction. The features of an edge element method including the volume and surface edge element method are inve... A finite element method with boundary element method (FEM-BEM) is presented for computing electromagnetic induction. The features of an edge element method including the volume and surface edge element method are investigated in depth. Surface basis functions of edge elements to an arbitrary shape of target are derived according to the geometrical property of basis functions and applied to discretize the surface integral equation for 3-D general targets. The proposed model is presented to compute resonant frequencies and surface current of underground unexplored ordnance (UXO), and then the electromagnetic responses of single target with different frequencies and positions of sensor are simulated and results are validated by experiments. 展开更多
关键词 Boundary element method Electromagnetic field effects Finite element method GEOMETRY Integral equations Radial basis function networks
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Research Progress of Soil Loss in Karst Areas under the Dual Structure of Southwest China 被引量:1
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作者 安吉平 王济 +2 位作者 蔡雄飞 段志斌 颜蒙蒙 《Agricultural Science & Technology》 CAS 2017年第8期1452-1458,共7页
The research progress of soil loss under the dual structure of southwest karst is systematically studied. The results show that the research of the soil erosion in karst mountainous area started late, and the basic re... The research progress of soil loss under the dual structure of southwest karst is systematically studied. The results show that the research of the soil erosion in karst mountainous area started late, and the basic research is lagging. Most of the existing research results focus on the present situation, causes and control measures of surface erosion. The view of underground soil loss in the context of karst diploid structure has been recognized by most scholars. However, limited to the research methods and the lack of observational data, the way of underground soil loss, the amount of loss and its harm are still unclear. Therefore, seeking the necessary technical means to carry out the necessary field observation from the way and process of loss is the focus of the study of soil loss under karst structure in the future. 展开更多
关键词 KARST Dual structure Surface soil erosion Underground soil loss
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Evaluation of Membership Degree on Conventional Chemical Components in Tobacco from Tobacco Leaf Bases in Yunnan Province Based on Cigarette Brands 被引量:2
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作者 Folin LI Yu CHEN +1 位作者 Wen OUYANG Kunyu REN 《Agricultural Science & Technology》 CAS 2017年第1期137-141,175,共6页
[Objective] This study was conducted to investigate the quality condition of chemical components of tobacco in Yunnan. [Method] The C3F samples were collected from 76 base units in Yunnan Province and their convention... [Objective] This study was conducted to investigate the quality condition of chemical components of tobacco in Yunnan. [Method] The C3F samples were collected from 76 base units in Yunnan Province and their conventional chemical components were analyzed, and the evaluation was carded out based on the membership function and hierarchical cluster analysis of cigarette brands H1 and H2 in Yunnan. [Result] The results showed that: (1) Major chemical components of 76 base units were coordinated overall. (2) Total nitrogen of brand H1 was higher than that of the high-quality tobacco leaves by 12.08%; raw tobacco of brands H3 and H2 satisfied the quality requirements of high-quality tobacco in Yunnan; and the total sugar and reducing sugar in flue-cured tobacco of brand H4 were higher those of the high-quality tobacco leaves by 0.76% and 10.3%, respectively. (3) The total sugar, reducing sugar and potassium of tobacco leaves from bases of G1 group were higher than those of tobacco from bases of G2 group by 38.1%, 2.27% and 7.34%, respectively; and total nitrogen and chlorine were lower by 4.69% and 11.11%, respectively; and nicotine contents in tobacco of the two groups were similar. (4) H2 and H3 were not significantly different in main chemical components; H3 and H4 were significantly different in total nitrogen, while other main chemical components were not significant different; and there were no significant differences between H4 and H2. [Conclusion] The quality of tobacco leaves from tobacco base units of G1 and G2 groups was better. Therefore, the evaluation provides theoretical reference for construction of tobacco base units. 展开更多
关键词 Membership function Base unit Conformity degree TOBACCO
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