期刊文献+
共找到13,976篇文章
< 1 2 250 >
每页显示 20 50 100
Establishment of Prediction Method of Tourism Meteorological Index in Langzhong Ancient City
1
作者 Rui MA Peiqiang WANG Yuhang YANG 《Meteorological and Environmental Research》 2024年第5期41-44,共4页
Based on the meteorological data of Langzhong from 2010 to 2020,the human body comfort index was calculated,and tourism climate comfort was evaluated to establish the prediction equation of tourism meteorological inde... Based on the meteorological data of Langzhong from 2010 to 2020,the human body comfort index was calculated,and tourism climate comfort was evaluated to establish the prediction equation of tourism meteorological index.OLS was used to compare the correlation between actual tourist flow and tourism meteorological index and test the model effect.Average correlation coefficient R was 0.7017,so the correlation was strong,and P value was 0.The two were significantly correlated at 0.01 level(bilateral).It can be seen that the forecast equation of tourism meteorological index had a strong correlation with the actual number of tourists,and the predicted value was basically close to the actual situation,and the forecast effect is good. 展开更多
关键词 Tourism meteorological index Climate assessment Correlation analysis Prediction method Langzhong City
下载PDF
Study on the evaluation index system and evaluation method for self-elevating drilling unit design 被引量:1
2
作者 王运龙 纪卓尚 《Journal of Marine Science and Application》 2009年第1期46-52,共7页
In the process of designing self-elevating drilling unit, it is important, yet complicated, to use comparison and filtering to select the optimum scheme from the feasible ones. In this research, an index system and me... In the process of designing self-elevating drilling unit, it is important, yet complicated, to use comparison and filtering to select the optimum scheme from the feasible ones. In this research, an index system and methodology for the evaluation of self-elevating drilling unit was proposed. Based on this, a multi-objective combinatorial optimization model was developed, using the improved grey relation Analysis (GRA), in which the analytic hierarchy process (AHP) was used to determine the weights of the evaluating indices. It considered the connections within the indices, reflecting the objective nature of things, and also considered the subjective interests of ship owners and the needs of designers. The evaluation index system and evaluation method can be used in the selection of an optimal scheme and advanced assessment. A case study shows the index system and evaluation method are scientific, reasonable, and easy to put into practice. At the same time, such an evaluation index system and evaluation method will be helpful for making decisions for other mobile platforms. 展开更多
关键词 self-elevating drilling unit evaluation index system evaluation method grey relation analysis (GRA) analytic hierarchy process (AHP)
下载PDF
Evaluation of regional water resources carrying capacity based on binary index method and reduction index method 被引量:13
3
作者 Hong-yuan Fang Sheng-wei Gan Chen-ying Xue 《Water Science and Engineering》 EI CAS CSCD 2019年第4期263-273,共11页
Based on the regional water resources carrying capacity(WRCC)evaluation principles and evaluation index system in the National Technical Outline of Water Resources Carrying Capacity Monitoring and Early Warning(hereaf... Based on the regional water resources carrying capacity(WRCC)evaluation principles and evaluation index system in the National Technical Outline of Water Resources Carrying Capacity Monitoring and Early Warning(hereafter referred to as the Technical Outline),this paper elaborates on the collection and sorting of the basic data of water resources conditions,water resources development and utilization status,social and economic development in basins,analysis and examination of integrity,consistency,normativeness,and rationality of the basic data,and the necessity of WRCC evaluation.This paper also describes the technique of evaluating the WRCC in prefecture-level cities and city-level administrative divisions in the District of the Taihu Lake Basin,which is composed of the Taihu Lake Basin and the Southeastern River Basin.The evaluation process combines the binary index evaluation method and reduction index evaluation method.The former,recommended by the Technical Outline,uses the total water use and the amount of exploited groundwater as evaluation indices,showing stronger operability,while the latter is developed by simplifying and optimizing the comprehensive index system with greater systematicness and completeness.The mutual validation and adjustment of the results of the above-mentioned two evaluation methods indicate that the WRCC of the District of the Taihu Lake Basin is overloaded in general because some prefecture-level cities and city-level administrative divisions in the Taihu Lake Basin and the Southeastern River Basin are in a severely overloaded state.In order to explain this conclusion,this paper analyzes the causes of WRCC overloading from the aspects of basin water environment,water resources development and utilization,water resources regulation and control ability,water resources utilization efficiency,and water resources management. 展开更多
关键词 Water resources carrying capacity(WRCC) EVALUATION Binary index method Reduction index method Prefecture-level cities and city-level administrative divisions
下载PDF
Construction of the First Certification Evaluation Index System for Diabetes Specialist Nurses by Delphi Method 被引量:4
4
作者 Haihua Zou Xue Gong +1 位作者 Siyun Wang Weiju Chen 《International Journal of Clinical Medicine》 2020年第5期242-251,共10页
Objective: To establish an evaluation index system for the first-time certification of diabetes specialist nurses in line with the clinical nursing practice in China, and to provide a reference basis for government ad... Objective: To establish an evaluation index system for the first-time certification of diabetes specialist nurses in line with the clinical nursing practice in China, and to provide a reference basis for government administrations and hospitals to formulate unified standards. Methods: After the research team has determined the theme, it will consult the development of A) specialist nursing through the library, Internet and electronic literature database;B) the history of the development of specialist nurses in diabetes and other fields;C) the selection criteria of specialist nurses;D) the training of specialist nurses system, assessment method;E) Specialist nurse certification body, evaluation standards and certification standards and other related documents, literature, books and report materials. The author established the preliminary index system through literature review, specialist interview and group discussion and used Delphi method to organize three rounds of 30 experts’ consultations. Results: A first certification evaluation index system including 8 fundamental indicators, 5 first-level indicators, 19 second-level indicators and 99 third-level indicators was constructed for diabetes nurses. Conclusion: The results of three rounds of expert consultation and demonstration are reliable, and the constructed index system is suitable for comprehensive evaluation of diabetes specialist nurses, which provides a basis for the effective management of nursing resources. 展开更多
关键词 DIABETIC SPECIALIST Nurses First CERTIFICATION Evaluation index DELPHI method
下载PDF
Evaluation of Natural Ecological Environment in Guangzhou City Based on Remote Sensing Technology and Comprehensive Index Method 被引量:4
5
作者 MA Jiaojiao NIU Anyi CHEN Zhiyun 《Journal of Landscape Research》 2016年第3期79-82,共4页
Based on the ETM remote sensing images of Guangzhou City in 2014, the spatial distribution results o f three environmental factors including vegetation coverage(NDVI), soil index(vegetation index of bare soil) and sl ... Based on the ETM remote sensing images of Guangzhou City in 2014, the spatial distribution results o f three environmental factors including vegetation coverage(NDVI), soil index(vegetation index of bare soil) and sl ope were obtained. By using comprehensive index method, the normalized environmental factors were weighted and superimposed, and the fi nal evaluation results of ecological environment in Guangzhou City were obtained. The results showed that overall situation of natural ecological environment in Guangzhou was not optimistic, that is, the area of land with bad, moderate, good and superior environment accounted for 59.70%, 35.79%, 4.50% and around 0.01% of total area of land in Guangzhou City respectively. Ecological environment was generally poor in the central urban districts in the south of Guangzhou City, while it was relatively better in the north and northeast. Attaching importance to the constr uction of greenbelts and greenways is an effective way to improve regional environmental quality and natural ecological e nvironment level. 展开更多
关键词 Remote sensing interpretation Natural ecological environment Comprehensive index method Environmental assessment GUANGZHOU
下载PDF
Comparison of delay compensation methods for real-time hybrid simulation using frequency-domain evaluation index 被引量:2
6
作者 Xu Weijie Guo Tong Chen Cheng 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2016年第1期129-143,共15页
The delay compensation method plays an essential role in maintaining the stability and achieving accurate real-time hybrid simulation results. The effectiveness of various compensation methods in different test scenar... The delay compensation method plays an essential role in maintaining the stability and achieving accurate real-time hybrid simulation results. The effectiveness of various compensation methods in different test scenarios, however, needs to be quantitatively evaluated. In this study, four compensation methods (i.e., the polynomial extrapolation, the linear acceleration extrapolation, the inverse compensation and the adaptive inverse compensation) are selected and compared experimentally using a frequency evaluation index (FEI) method. The effectiveness of the FEI method is first verified through comparison with the discrete transfer fimction approach for compensation methods assuming constant delay. Incomparable advantage is further demonstrated for the FEI method when applied to adaptive compensation methods, where the discrete transfer function approach is difficult to implement. Both numerical simulation and laboratory tests with predefined displacements are conducted using sinusoidal signals and random signals as inputs. Findings from numerical simulation and experimental results demonstrate that the FEI method is an efficient and effective approach to compare the performance of different compensation methods, especially for those requiring adaptation of compensation parameters. 展开更多
关键词 real-time hybrid simulation frequency domain evaluation index delay compensation methods
下载PDF
A sludge volume index (SVI) model based on the multivariate local quadratic polynomial regression method 被引量:4
7
作者 Honggui Han Xiaolong Wu +1 位作者 Luming Ge Junfei Qiao 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第5期1071-1077,共7页
In this study, a multivariate local quadratic polynomial regression(MLQPR) method is proposed to design a model for the sludge volume index(SVI). In MLQPR, a quadratic polynomial regression function is established to ... In this study, a multivariate local quadratic polynomial regression(MLQPR) method is proposed to design a model for the sludge volume index(SVI). In MLQPR, a quadratic polynomial regression function is established to describe the relationship between SVI and the relative variables, and the important terms of the quadratic polynomial regression function are determined by the significant test of the corresponding coefficients. Moreover, a local estimation method is introduced to adjust the weights of the quadratic polynomial regression function to improve the model accuracy. Finally, the proposed method is applied to predict the SVI values in a real wastewater treatment process(WWTP). The experimental results demonstrate that the proposed MLQPR method has faster testing speed and more accurate results than some existing methods. 展开更多
关键词 Sludge volume index Multivariate quadratic polynomial regression Local estimation method Wastewater treatment process
下载PDF
Analysis of one-dimensional rheological consolidation of double-layered soil with fractional derivative Merchant model and non-Darcian flow described by non-Newtonian index 被引量:3
8
作者 CUI Peng-lu LIU Zhong-yu +1 位作者 ZHANG Jia-chao FAN Zhi-cheng 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第1期284-296,共13页
To further investigate the one-dimensional(1D)rheological consolidation mechanism of double-layered soil,the fractional derivative Merchant model(FDMM)and the non-Darcian flow model with the non-Newtonian index are re... To further investigate the one-dimensional(1D)rheological consolidation mechanism of double-layered soil,the fractional derivative Merchant model(FDMM)and the non-Darcian flow model with the non-Newtonian index are respectively introduced to describe the deformation of viscoelastic soil and the flow of pore water in the process of consolidation.Accordingly,an 1D rheological consolidation equation of double-layered soil is obtained,and its numerical analysis is performed by the implicit finite difference method.In order to verify its validity,the numerical solutions by the present method for some simplified cases are compared with the results in the related literature.Then,the influence of the revelent parameters on the rheological consolidation of double-layered soil are investigated.Numerical results indicate that the parameters of non-Darcian flow and FDMM of the first soil layer greatly influence the consolidation rate of double-layered soil.As the decrease of relative compressibility or the increase of relative permeability between the lower soil and the upper soil,the dissipation rate of excess pore water pressure and the settlement rate of the ground will be accelerated.Increasing the relative thickness of soil layer with high permeability or low compressibility will also accelerate the consolidation rate of double-layered soil. 展开更多
关键词 double-layered soil rheological consolidation fractional derivative non-Darcian flow non-newtonian index finite difference method viscoelasticity
下载PDF
The study of coal mine equipment’s comprehensive evaluation index system and evaluation method 被引量:2
9
作者 王新华 史国庆 《Journal of Coal Science & Engineering(China)》 2004年第2期117-121,共5页
Equipment management is one of the important parts of business administra- tion of coal. Most of coal mines take no account of their equipment management, and have no comprehensive and effective evaluation index syste... Equipment management is one of the important parts of business administra- tion of coal. Most of coal mines take no account of their equipment management, and have no comprehensive and effective evaluation index system. Based on the analysis of the equipment evaluation measures of reform and the applications, the paper built up a comprehensive and effective evaluation index system of coal mine equipment, and im- proved the evaluation method with the use of fuzzy theory, analytic hierarchy process and entropy method. 展开更多
关键词 equipment of coal mine comprehensive evaluation index system fuzzy theory entropy method
下载PDF
Determination of Fructose and Glucose Contents in Honey by Liquid Chromatography-refractive Index Detection Method and Direct Titration Method 被引量:1
10
作者 Xiaoya PU Xusheng DU +1 位作者 Bo LIU Hua ZHANG 《Agricultural Biotechnology》 CAS 2016年第2期31-33,共3页
In this study, fructose and glucose contents in honey were determined by liquid chromatography-refractive index detection method and alkaline copper tartrate solution-direct titration method. According to the results,... In this study, fructose and glucose contents in honey were determined by liquid chromatography-refractive index detection method and alkaline copper tartrate solution-direct titration method. According to the results, there were great differences between determination results of reducing sugar contents by liquid chromatography-refractive index detection method and alkaline copper tartrate solution-direct titration method. Specifically, average determination results of reducing sugar contents by liquid chromatography-refractive index detection method were reduced by about 9.5% compared with alkaline copper tartrate solution-direct titra- tion method. Subsequently, determination results of reducing sugar contents by two methods were compared and analyzed. Liquid chromatography-refractive index detection method was used to determine fructose and glucose monomers in honey, but alkaline copper tartrate solution-direct titration method was used to determine reducing sugar composition in honey, which might lead to significantly different results. Due to small sample size and limited conditions, the determination results were not necessarily representative. Bee product acquisition and processing enterprises and relevant departments should pay much attention on these issues and fully consider the current situation of grass-roots units to develop scientific, rigorous, simple, universal, convenient, low-cost and practicable standards, thus ensuring the safety and reliability of food quality. 展开更多
关键词 HONEY FRUCTOSE GLUCOSE Liquid chromatography with refractive index detection method
下载PDF
Index system and methods for comprehensive assessment of cross-border power grid interconnection projects 被引量:1
11
作者 Teng Zhao Yizhe Jiang +4 位作者 Han Jiang Yi Gao Wei Wu Chen Wang Jinxiang Zhu 《Global Energy Interconnection》 CAS 2020年第6期532-544,共13页
With the global economy integration and progress in energy transformation,it has become a general trend to surpass national boundaries to achieve wider and optimal energy resource allocations.Consequently,there is a c... With the global economy integration and progress in energy transformation,it has become a general trend to surpass national boundaries to achieve wider and optimal energy resource allocations.Consequently,there is a critical n eed to adopt scie ntific approaches in assessi ng cross-border power grid interconnection projects.First,con sidering the promotion of large-scale renewable energy resources and improvements in system adequacy,a comprehensive assessment index system,including costs,socio-economic benefits,environmental benefits,and technical benefits,is established in this study.Second,a synthetic assessment framework is proposed for cross-border power grid interconnection projects based on the index system comprising cost-benefit analysis,with market and network simulations,iterative methods for indicator weight evaluation,and technique for order preferenee by similarity to an ideal solution(TOPSIS)method for the project rankings.Fin ally,by assessi ng and comparing three cross-border projects betwee n Europe and Asia,the proposed index system and assessment framework have been proved to be effective and feasible;the results of this system can thus support investment decision-making related to such projects in the future. 展开更多
关键词 Cross-border power grid interconnection Comprehensive assessment index system Cost-benefit analysis Iterative method TOPSIS method
下载PDF
A new estimation method and an anisotropy index for the deformation modulus of jointed rock masses 被引量:1
12
作者 Bohu Zhang Junyan Mu +2 位作者 Jun Zheng Qing Lv Jianhui Deng 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2022年第1期153-168,共16页
The deformation modulus of a rock mass is an important parameter to describe its mechanical behavior.In this study,an analytical method is developed to determine the deformation modulus of jointed rock masses,which co... The deformation modulus of a rock mass is an important parameter to describe its mechanical behavior.In this study,an analytical method is developed to determine the deformation modulus of jointed rock masses,which considers the mechanical properties of intact rocks and joints based on the superposition principle.Due to incorporating the variations in the orientations and sizes of joint sets,the proposed method is applicable to the rock mass with persistent and parallel joints as well as that with nonpersistent and nonparallel joints.In addition,an anisotropy index AIdmfor the deformation modulus is defined to quantitatively describe the anisotropy of rock masses.The range of AIdmis from 0 to 1,and the more anisotropic the rock mass is,the larger the value of AIdmwill be.To evaluate the proposed method,20 groups of numerical experiments are conducted with the universal distinct element code(UDEC).For each experimental group,the deformation modulus in 24 directions are obtained by UDEC(numerical value)and the proposed method(predicted value),and then the mean error rates are calculated.Note that the mean error rate is the mean value of the error rates of the deformation modulus in 24 directions,where for each direction,the error rate is equal to the ratio of numerical value minus predicted value to the numerical value.The results show that(i)for different experimental groups,the mean error rates vary between 5.06%and 22.03%;(ii)the error rates for the discrete fracture networks(DFNs)with two sets of joints are at the same level as those with one set of joints;and(iii)therefore,the proposed method for estimating the deformation modulus of jointed rock masses is valid. 展开更多
关键词 Deformation modulus Analytical method Anisotropy index Jointed rock masses Mechanical behavior Discrete fracture network(DFN)
下载PDF
A Method for Determining the Reliability Index of a Materiel Subsystem 被引量:2
13
作者 RENJian-jun ZHANGXi-bin 《International Journal of Plant Engineering and Management》 2002年第4期234-240,共7页
This paper presents a method for determining the reliability index of a subsystem in the materiel demonstration phase-AHP Failure Rate Method. It fully considers the various factors which influence a subsystem reliabi... This paper presents a method for determining the reliability index of a subsystem in the materiel demonstration phase-AHP Failure Rate Method. It fully considers the various factors which influence a subsystem reliability index and solves a difficult problem that puzzles the demonstration personnel. 展开更多
关键词 materiel subsystem reliability index AHP failure rate method
下载PDF
A Double-Index Method to Classify Kuroshio Intrusion Paths in the Luzon Strait 被引量:6
14
作者 Zhida HUANG Hailong LIU +1 位作者 Jianyu HU Pengfei LIN 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2016年第6期715-729,共15页
A double index (DI), which is made up of two sub-indices, is proposed to describe the spatial patterns of the Kuroshio intrusion and mesoscale eddies west to the Luzon Strait, based on satellite altimeter data. The ... A double index (DI), which is made up of two sub-indices, is proposed to describe the spatial patterns of the Kuroshio intrusion and mesoscale eddies west to the Luzon Strait, based on satellite altimeter data. The area-integrated negative and positive geostrophic vorticities are defined as the Kuroshio warm eddy index (KWI) and the Kuroshio cold eddy index (KCI), respectively. Three typical spatial patterns are identified by the DI: the Kuroshio warm eddy path (KWEP), the Kuroshio cold eddy path (KCEP), and the leaking path. The primary features of the DI and three patterns are further investigated and compared with previous indices. The effects of the integrated area and the algorithm of the integration are investigated in detail. In general, the DI can overcome the problem of previously used indices in which the positive and negative geostrophic vorticities cancel each other out. Thus, the proportions of missing and misjudged events are greatly reduced using the DI. The DI, as compared with previously used indices, can better distinguish the paths of the Kuroshio intrusion and can be used for further research. 展开更多
关键词 Luzon Strait Kuroshio intrusion mesoscale eddy double-index method
下载PDF
Kind of Fuzzy Method Determining Index Weight on Multi-Objctive Decision Making
15
作者 程国明 黄侃 《International Journal of Mining Science and Technology》 SCIE EI 1999年第2期211-214,共4页
Based on fuzzy characteristic of dicision-making thought, matrix of priority relation has been introduced and blurrized. A kind of fuzzy method, which is to determine the index weight on multi-objective decision makin... Based on fuzzy characteristic of dicision-making thought, matrix of priority relation has been introduced and blurrized. A kind of fuzzy method, which is to determine the index weight on multi-objective decision making, has been put forward by means of the sequence root method for analysis of hierarchical process (AHP). Using this method an example which is to define the index weigbt on multi-objective decision making in thc scheme optimization of mine design has been given. 展开更多
关键词 fuzzy method index weight MULTI-OBJECTIVE decision making CONSISTENCY MINE design
下载PDF
Research on the statistics index system and evaluation method of high and new technology industry development
16
作者 李晓东 张霞 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2004年第3期334-337,共4页
During the evolution of the global economic, high and new technology industry has become the main driver to impel the global economy growth via technological advancement, and the main means to guarantee the sustainabl... During the evolution of the global economic, high and new technology industry has become the main driver to impel the global economy growth via technological advancement, and the main means to guarantee the sustainable development of the global economy. In the view of China’s situation, this article analyzes the experiences of OECD in high and new technology industry and gives a statistics index system along with the evaluation method to estimate the development of high and new technology industry. 展开更多
关键词 High and new technology industry DEVELOPMENT Statistics index system Evaluation method
下载PDF
基于U2-Net深度网络和投影波谷法的在架图书错序检测
17
作者 王红芳 王宇航 +1 位作者 宣静雯 张凯兵 《现代电子技术》 北大核心 2024年第3期149-154,共6页
针对在架图书错序检测中图书索书号区域的准确定位关键问题,提出一种基于U2⁃Net深度网络和投影波谷法的在架图书索书号区域定位识别方法。该方法首先使用U2⁃Net深度网络对在架图书索书号区域进行预分割,然后通过投影波谷法对每本图书的... 针对在架图书错序检测中图书索书号区域的准确定位关键问题,提出一种基于U2⁃Net深度网络和投影波谷法的在架图书索书号区域定位识别方法。该方法首先使用U2⁃Net深度网络对在架图书索书号区域进行预分割,然后通过投影波谷法对每本图书的索书号区域进一步精确分割,最后对分割出的索书号区域图像使用光学字符识别技术,完成对索书号的识别,通过对识别结果进行排序关系判断,完成错序检测过程。实验结果表明,该方法能实现准确的索书号区域图像分割,为图书馆智能化管理提供了有效的解决方案。 展开更多
关键词 深度网络 U2⁃Net 投影波谷法 图书错序检测 光学字符识别 索书号定位
下载PDF
Axle-equivalent method of steel-deck pavement 被引量:3
18
作者 张磊 钱振东 +1 位作者 程刚 刘振清 《Journal of Southeast University(English Edition)》 EI CAS 2006年第1期96-100,共5页
An index system of steel deck pavement design is proposed according to the study and classification of failure types. Furthermore the axle-equivalent equation is presented according to the fatigue principle of pavemen... An index system of steel deck pavement design is proposed according to the study and classification of failure types. Furthermore the axle-equivalent equation is presented according to the fatigue principle of pavement structures. Based on indoor experiments and theoretical analysis, this paper studies the stress characteristics of three different axle types which are corresponding with the other three typical pavement structures, and also presents the parameters of each axle's equivalent formula. The three axle types include single-axle single-wheel, single-axle double-wheel and double-axle double-wheel. According to analyses of influential factors such as climate, environment, traffic and stress condition, the developed axle equivalent formula and the parameters modified by the field test data can be applied in the design of a new bridge deck pavement and the assessment of an existing bridge deck pavement. 展开更多
关键词 steel bridge asphalt mixture PAVEMENT fatigue-equivalent principle axle-equivalent method index
下载PDF
Derwent Innovations Index数据库的主要特点及其检索方法 被引量:12
19
作者 郑伟 《中国索引》 2009年第1期56-60,共5页
Derwent Innovations Index收录全面的专利文献,可以综合检索世界各国的专利文献,包括世界各地化学、电子电气以及工程技术领域内综合全面的发明信息,本文介绍该系统的特点、检索途径与方法等。
关键词 德温特 检索方法 DERWENT Innovations index RETRIEVAL methodS
下载PDF
石灰性土壤起始NO_3^-N对土壤供氮能力测定方法的影响 被引量:21
20
作者 叶优良 李生秀 《植物营养与肥料学报》 CAS CSCD 北大核心 2002年第3期310-317,共8页
在陕西省的澄城、永寿、杨陵 3地区选取有机质、全N、硝态N含量差异较大的 17个石灰性土壤 ,分别在淋洗与未淋洗土壤起始NO-3 N后 ,利用盆栽试验探讨土壤NO-3 N淋洗前、后 ,不同方法测定的已矿化N和可矿化N与小麦吸N量之间的相关性。... 在陕西省的澄城、永寿、杨陵 3地区选取有机质、全N、硝态N含量差异较大的 17个石灰性土壤 ,分别在淋洗与未淋洗土壤起始NO-3 N后 ,利用盆栽试验探讨土壤NO-3 N淋洗前、后 ,不同方法测定的已矿化N和可矿化N与小麦吸N量之间的相关性。结果表明 ,未淋洗土壤起始NO-3 N ,用KCl直接浸取、KCl煮沸法所浸取以及通气培养前CaCl2 所淋洗的起始NO-3 N均与小麦吸N量密切相关 ,相关系数 (r)分别为 0 934 ,0 85 6和 0 86 2 ,均达1%显著水准。与此相反 ,通气培养、淹水培养、沸水煮沸、碱性高锰酸钾、酸性高锰酸钾及碱解扩散等方法所提取的可矿化N与小麦吸N量间无显著相关。淋洗土壤起始NO-3 N后 ,用KCl直接浸取、KCl煮沸法浸取以及通气培养前CaCl2 所淋洗的起始NO-3 N与小麦吸N量之间的相关系数明显降低 ,达不到 5 %的显著水准。而通气培养、淹水培养、沸水煮沸、碱性高锰酸钾、酸性高锰酸钾及碱解扩散等方法所提取的可矿化N与小麦吸N量之间相关系数却明显提高 ,都达到 5 %或 1%的显著水平。其中变化最明显的是淹水培养 1周矿化出的NH+ 4 N、通气正式培养 2周矿化出的NO-3 N及碱解扩散出的NH+ 4 N ,其与小麦地上部吸N量之间的相关系数 (r)分别由淋洗前的0 44 3,0 119,0 2 5 9增加到淋洗后的 0 86 6 。 展开更多
关键词 石灰性土壤 起始NO3^--n 土壤供氮能力 测定方法
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部