期刊文献+
共找到20,303篇文章
< 1 2 250 >
每页显示 20 50 100
Analysis of Perioperative Respiratory Care Methods and their Application Value in Children with Congenital Heart Disease
1
作者 Liangyin Quan 《Journal of Clinical and Nursing Research》 2024年第2期22-27,共6页
Objective:To analyze the perioperative respiratory care methods and application value in children with congenital heart disease.Methods:60 children with congenital heart disease(treated from January 2021 to October 20... Objective:To analyze the perioperative respiratory care methods and application value in children with congenital heart disease.Methods:60 children with congenital heart disease(treated from January 2021 to October 2023)were screened and divided into two groups randomly.Each group consisted of 30 cases.The perioperative routine was used in the control group.The observation group underwent the perioperative routine along with better respiratory care.Oxygenation indicators,surgical complications,and family satisfaction levels of the groups were compared.Results:There was no significant difference in the oxygenation index between the two groups of children at admission(P>0.05).At discharge,the oxygenation indicators in the observation group were better than those of the control group,and the incidence of surgical complications was lower than that of the control group.The total satisfaction of family members in the observation group was higher than that of the control group(P<0.05).Conclusion:During the perioperative period for children with congenital heart disease,the implementation of respiratory care,which mainly involves symptomatic care,catheter care,sputum suction care,etc.,can actively improve the oxygenation indicators,reduce surgical complications,and promote faster and better recovery,of children with congenital heart disease. 展开更多
关键词 Congenital heart disease Perioperative respiratory care Nursing methods and value
下载PDF
A Study of EM Algorithm as an Imputation Method: A Model-Based Simulation Study with Application to a Synthetic Compositional Data
2
作者 Yisa Adeniyi Abolade Yichuan Zhao 《Open Journal of Modelling and Simulation》 2024年第2期33-42,共10页
Compositional data, such as relative information, is a crucial aspect of machine learning and other related fields. It is typically recorded as closed data or sums to a constant, like 100%. The statistical linear mode... Compositional data, such as relative information, is a crucial aspect of machine learning and other related fields. It is typically recorded as closed data or sums to a constant, like 100%. The statistical linear model is the most used technique for identifying hidden relationships between underlying random variables of interest. However, data quality is a significant challenge in machine learning, especially when missing data is present. The linear regression model is a commonly used statistical modeling technique used in various applications to find relationships between variables of interest. When estimating linear regression parameters which are useful for things like future prediction and partial effects analysis of independent variables, maximum likelihood estimation (MLE) is the method of choice. However, many datasets contain missing observations, which can lead to costly and time-consuming data recovery. To address this issue, the expectation-maximization (EM) algorithm has been suggested as a solution for situations including missing data. The EM algorithm repeatedly finds the best estimates of parameters in statistical models that depend on variables or data that have not been observed. This is called maximum likelihood or maximum a posteriori (MAP). Using the present estimate as input, the expectation (E) step constructs a log-likelihood function. Finding the parameters that maximize the anticipated log-likelihood, as determined in the E step, is the job of the maximization (M) phase. This study looked at how well the EM algorithm worked on a made-up compositional dataset with missing observations. It used both the robust least square version and ordinary least square regression techniques. The efficacy of the EM algorithm was compared with two alternative imputation techniques, k-Nearest Neighbor (k-NN) and mean imputation (), in terms of Aitchison distances and covariance. 展开更多
关键词 Compositional Data Linear Regression Model Least Square method Robust Least Square method Synthetic Data Aitchison Distance Maximum Likelihood Estimation Expectation-Maximization Algorithm k-Nearest Neighbor and Mean imputation
下载PDF
Research on the Coupled and Coordinated Development of Tourism and Transport in Chengdu City
3
作者 Min Kang Qiguang Lv 《Proceedings of Business and Economic Studies》 2024年第3期6-15,共10页
Based on a total of 16 indicators selected from the tourism and transport industries,an evaluation index system of the coupling and coordination development level of tourism and transport is constructed.The entropy va... Based on a total of 16 indicators selected from the tourism and transport industries,an evaluation index system of the coupling and coordination development level of tourism and transport is constructed.The entropy value method and the coupling coordination degree model are used to conduct an empirical study on the development level and coupling coordination level of the transport and tourism industries in Chengdu City from 2011 to 2020.The results show that,on the whole,the coupling coordination degree of transport and tourism in Chengdu is poor and has been in a state of mild to moderate dysfunction.The development level of tourism lagged behind the development of transport from 2011 to 2012,and the two were in a state of mild dysfunction.However,from 2013 onwards,the development level of tourism was prioritized over the development level of transport.This shift caused the coupling coordination degree of the two industries to decline sharply to 0.23305 in 2013.The development level of the tourism industry increased again,reaching 0.34206 in 2019,which marked an improvement.Consequently,the coordination degree of the transport and tourism industries evolved from moderate dislocation to mild dislocation.Finally,the results of the empirical research are analyzed,and corresponding suggestions are put forward to promote the sustainable growth of the transport and tourism industries in Chengdu City.These suggestions aim to improve the coupled and coordinated development level of the two industries. 展开更多
关键词 Coupling coordination Chengdu city Transport industry tourism industry Entropy value method Coupling coordination degree model
下载PDF
A two-parameter multiple shooting method and its application to the natural vibrations of non-prismatic multi-segment beams
4
作者 R.HOŁUBOWSKI K.JARCZEWSKA 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第12期2243-2252,共10页
This paper presents an enhanced version of the standard shooting method that enables problems with two unknown parameters to be solved.A novel approach is applied to the analysis of the natural vibrations of Euler-Ber... This paper presents an enhanced version of the standard shooting method that enables problems with two unknown parameters to be solved.A novel approach is applied to the analysis of the natural vibrations of Euler-Bernoulli beams.The proposed algorithm,named as two-parameter multiple shooting method,is a new powerful numerical tool for calculating the natural frequencies and modes of multi-segment prismatic and non-prismatic beams with different boundary conditions.The impact of the axial force and additional point masses is also taken into account.Due to the fact that the method is based directly on the fourth-order ordinary differential equation,the structures do not have to be divided into many small elements to obtain an accurate enough solution,even though the geometry is very complex.To verify the proposed method,three different examples are considered,i.e.,a three-segment non-prismatic beam,a prismatic column subject to non-uniformly distributed compressive loads,and a two-segment beam with an additional point mass.Numerical analyses are carried out with the software MATHEMATICA.The results are compared with the solutions computed by the commercial finite element program SOFiSTiK.Good agreement is achieved,which confirms the correctness and high effectiveness of the formulated algorithm. 展开更多
关键词 two-parameter multiple shooting method two-point boundary value problem natural vibration non-prismatic beam multi-segment beam
下载PDF
Valuing options to renew at future market value:the case of commercial property leases
5
作者 Jenny Jing Wang Jianfu Shen Frederik Pretorius 《Financial Innovation》 2023年第1期1932-1966,共35页
In this study,we develop and empirically test a valuation model for a commonly encountered option in office leases:a tenant’s option to renew at future market rent(a fair market value)with lease termination as the ma... In this study,we develop and empirically test a valuation model for a commonly encountered option in office leases:a tenant’s option to renew at future market rent(a fair market value)with lease termination as the maturity date.The model integrates decision analysis with real options analysis and market risk with private risks.“Option value”is defined as the private value of the option to either party pre-contract,while“option price”assumes a fair agreement between transacting parties and can be positive(rental premium paid)or negative(rental discount offered).Without manifest expectations,an analysis of a sample of office leases supports the model’s logic with price estimates in a practical range.The tenants’option price/value is shown to have a negative relationship with the original/renewal lease term;conversely,the landlords’option value is positively related to the original/renewal term.Comparative analyses show that transaction costs have a positive effect on tenants’option value and on prices,while vacancy costs and the vacancy period are both positively related to the landlords’option value and negatively related to price.Market rent is found to have a negative relationship with option price.Overall,this study provides a theoretical analysis and empirical tests of the value of a real option that allows option holders to renew/extend their contracts at a fair market value. 展开更多
关键词 Fair market value renewal Commercial property leases Real option VALUATION Integrated method
下载PDF
Using a Spatial Convolution Method to Estimate Ecosystem Services Values at Regional Level: a Case Study in Northeast China 被引量:1
6
作者 何英彬 唐华俊 +4 位作者 陈佑启 姚艳敏 杨鹏 李建平 辛晓平 《Journal of Landscape Research》 2010年第7期1-6,共6页
Since the introduction of the concept, studies on valuation of ecosystem services have been overwhelming, in cognizance of its great significance. In this article, the authors took Northeast China as the study area an... Since the introduction of the concept, studies on valuation of ecosystem services have been overwhelming, in cognizance of its great significance. In this article, the authors took Northeast China as the study area and applied the published coefficients for the world by Costanza to calculate the ecosystem services values through a spatial convolution method. The convolution analysis was done with a square processor with 5×5 neighborhood cells. The results showed that the ecosystem services value for the study area in the year 2003 was US$44 990 million which is US$89 million less than the value without operation, and the main contributions for that decrease were from water bodies, wetlands and estuaries. It is expected that this article can attract more interest to explore this field adopting geographic methods. 展开更多
关键词 ECOSYSTEM services values GEOGRAPHICAL SPATIAL convolution method Estimation SPATIAL HETEROGENEITY BIOMES
下载PDF
A circular zone counting method of identifying a Duffing oscillator state transition and determining the critical value in weak signal detection 被引量:3
7
作者 李梦平 许雪梅 +1 位作者 杨兵初 丁家峰 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第6期192-197,共6页
Identifying state transition and determining the critical value of the Duffing oscillator are crucial to indicating external signal existence and have a great influence on detection accuracy in weak signal detection. ... Identifying state transition and determining the critical value of the Duffing oscillator are crucial to indicating external signal existence and have a great influence on detection accuracy in weak signal detection. A circular zone counting (CZC) method is proposed in this paper, by combining the Duffing oscillator's phase trajectory feature and numerical calculation for quickly and accurately identifying state transition and determining the critical value, to realize a high- efficiency weak signal detection. Detailed model analysis and method construction of the CZC method are introduced. Numerical experiments into the reliability of the proposed CZC method compared with the maximum Lyapunov exponent (MLE) method are carried out. The CZC method is demonstrated to have better detecting ability than the MLE method, and furthermore it is simpler and clearer in calculation to extend to engineering application. 展开更多
关键词 identifying state transition determining critical value Duffing oscillator circular zone countingmethod maximum Lyapunov exponent method
下载PDF
A Microcomputer Fitted Method for Determination of the True ODF of Hexagonal Materials according to the Maximum-Entropy Estimate 被引量:1
8
作者 Liqing CHEN Fu WANG Zhide LIANG Dept.of Materials Science and Engineering,Northeast University of Technology.Shenyang,110006,China 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1993年第1期71-73,共3页
A method which is especially suitable for microcomputer calculation of the true orientation distribution function (ODF) according to the maximum-entropy estimate is proposed for hexagonal system polycrystalline materi... A method which is especially suitable for microcomputer calculation of the true orientation distribution function (ODF) according to the maximum-entropy estimate is proposed for hexagonal system polycrystalline materials with physical symmetry.The resultant computational software system has been also designed and first carried out in a microcomputer PANAFACOM-U1200 being on line with the X-ray diffractometer D/max-3A.The simu- lated calculation shows that the method is concisely pragmatic and easily popularized,while the results obtained are trust worthy. 展开更多
关键词 ODF maximum-entropy estimate microcomputer fitted method
下载PDF
On the Application of Adomian Decomposition Method to Special Equations in Physical Sciences
9
作者 Aishah Alsulami Mariam Al-Mazmumy +1 位作者 Huda Bakodah Nawal Alzaid 《American Journal of Computational Mathematics》 2023年第3期387-397,共11页
The current manuscript makes use of the prominent iterative procedure, called the Adomian Decomposition Method (ADM), to tackle some important special differential equations. The equations of curiosity in this study a... The current manuscript makes use of the prominent iterative procedure, called the Adomian Decomposition Method (ADM), to tackle some important special differential equations. The equations of curiosity in this study are the singular equations that arise in many physical science applications. Thus, through the application of the ADM, a generalized recursive scheme was successfully derived and further utilized to obtain closed-form solutions for the models under consideration. The method is, indeed, fascinating as respective exact analytical solutions are accurately acquired with only a small number of iterations. 展开更多
关键词 Iterative Scheme Adomian Decomposition method Initial-value Problems Singular Ordinary Differential Equations
下载PDF
AN ASYMPTOTIC BEHAVIOR AND A POSTERIORI ERROR ESTIMATES FOR THE GENERALIZED SCHWARTZ METHOD OF ADVECTION-DIFFUSION EQUATION
10
作者 Salah BOULAARAS Mohammed Said TOUATI BRAHIM +1 位作者 Smail BOUZENADA Abderrahmane ZARAI 《Acta Mathematica Scientia》 SCIE CSCD 2018年第4期1227-1244,共18页
In this paper, a posteriori error estimates for the generalized Schwartz method with Dirichlet boundary conditions on the interfaces for advection-diffusion equation with second order boundary value problems are prove... In this paper, a posteriori error estimates for the generalized Schwartz method with Dirichlet boundary conditions on the interfaces for advection-diffusion equation with second order boundary value problems are proved by using the Euler time scheme combined with Galerkin spatial method. Furthermore, an asymptotic behavior in Sobolev norm is de- duced using Benssoussau-Lions' algorithm. Finally, the results of some numerical experiments are presented to support the theory. 展开更多
关键词 a posteriori error estimates GODDM ADVECTION-DIFFUSION Galerkin method Benssoussan-Lions' algorithm
下载PDF
A SPECIAL METHOD OF FOURIER SERIES WHICH IS EQUAL TO THE METHOD OF SEPARATION OF VARIABLES ON BOUNDARY VALUE PROBLEM
11
作者 Yan Xianggan Wu Jike, Department of Mechanics, Peking Unirersity, Bejing 100871. China 《Acta Mechanica Solida Sinica》 SCIE EI 1997年第3期255-261,共7页
By the separation of singularity, a special Fourier series solution of the boundary value problem for plane is obtained, which can satisfy all boundary conditions and converges rapidly. II is proved that the solution ... By the separation of singularity, a special Fourier series solution of the boundary value problem for plane is obtained, which can satisfy all boundary conditions and converges rapidly. II is proved that the solution is equal to the result of separation of variables. As a result, the non-linear characteristic equations resulting from the method of separation of variables are transformed into polynomial equations that can provide a foundation for approximate computation and asymptotic analysis. 展开更多
关键词 separation of singularity series resolution method of separation of variables boundary value problem characteristic equation
下载PDF
Estimation of Acute Toxicity of Ammonium Sulphate to the Fresh Water Catfish,Heteropneustes fossilis——Ⅰ.Analysis of LC_(50) Values Determined by Various Methods
12
作者 TARUNK.BANERJEE 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 1993年第1期31-36,共6页
The acute toxic effects of ammonium sulphate to fresh-water catfish, Heteropneustes fossilis (H.fossilis) have been studied by determining LC50 values with 95% confidence limits, by the graphic method, the logistic me... The acute toxic effects of ammonium sulphate to fresh-water catfish, Heteropneustes fossilis (H.fossilis) have been studied by determining LC50 values with 95% confidence limits, by the graphic method, the logistic method, the Spearman and Karber method and the trimmed Spearman-Karber method. The trimmed Spearman-Karber method was found the most ideal for ammonium salt toxicity test. The flaws in the trimmed Spearman-Karber method are also discussed. 展开更多
关键词 values Determined by Various methods Analysis of LC Estimation of Acute toxicity of Ammonium Sulphate to the Fresh Water Catfish Heteropneustes fossilis
下载PDF
Using an Alternative Method to Estimate the Status of Iodine Nutrition in Pregnant Women
13
作者 LIU Xiao Bing WU Meng +4 位作者 ZHANG Yu WANG Lei PIAO Jian Hua YANG Li Chen YANG Xiao Guang 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2018年第7期535-538,共4页
Iodine is an element that is essential for the synthesis of thyroid hormones.Adequate intake of dietary iodine has been recognized as a critical factor for maintaining health.It is a well-known fact that iodine defici... Iodine is an element that is essential for the synthesis of thyroid hormones.Adequate intake of dietary iodine has been recognized as a critical factor for maintaining health.It is a well-known fact that iodine deficiency can impede the production of thyroid hormones in both the mother and fetus,which increases the risk of brain damage in the fetal stage. 展开更多
关键词 CR UIC Using an Alternative method to estimate the Status of Iodine Nutrition in Pregnant Women UIE
下载PDF
A METHOD OF ESTIMATING THE INFLUENCE OF EXPERIMENTAL ERRORS ON THE EXPERIMENTAL RESULTS OF MATERIAL PARAMETERS AND THE CRITERIA TO VALUE THIS INFLUENCE
14
作者 Yao Weixing Tsinghua University 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 1991年第3期320-325,共6页
In this paper the main sources causing the scatter of the experimental results of the material parameters are discussed. They can be divided into two parts: one is the experimental errors which are introduced because ... In this paper the main sources causing the scatter of the experimental results of the material parameters are discussed. They can be divided into two parts: one is the experimental errors which are introduced because of the inaccuracy of experimental equipment, the experimental techniques, etc., and the form of the scatter caused by this source is called external distribution. The other is due to the irregularity and inhomogeneity of the material structure and the randomness of deformation process. The scatter caused by this source is inherent and then this form of the scatter is called internal distribution. Obviously the experimental distribution of material parameters combines these two distributions in some way; therefore, it is a sum distribution of the external distribution and the internal distribution. In view of this , a general method used to analyse the influence of the experimental errors on the experimental results is presented, and three criteria used to value this influence are defined. An example in which the fracture toughness KIC is analysed shows that this method is reasonable, convenient and effective. 展开更多
关键词 A method of ESTIMATING the INFLUENCE of EXPERIMENTAL ERRORS ON the EXPERIMENTAL RESULTS of MATERIAL PARAMETERS AND the CRITERIA to value THIS INFLUENCE
下载PDF
Data-Driven Adaptive Predictive Control Method With Autotuned Weighting Factor for Nonlinear Systems Using Triangular Dynamic Linearization
15
作者 Zhong-Hua Pang Yumo Zhang +2 位作者 Xueyuan Sun Shengnan Gao Guo-Ping Liu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第8期1880-1882,共3页
Dear Editor,In this letter,a novel data-driven adaptive predictive control method is proposed using the triangular dynamic linearization technique.The proposed method only contains one time-varying parameter with expl... Dear Editor,In this letter,a novel data-driven adaptive predictive control method is proposed using the triangular dynamic linearization technique.The proposed method only contains one time-varying parameter with explicit physical meaning,which can prevent severe deviation in parameter estimation.Specifically,a triangular dynamic linearization(TDL)data model is employed to predict future system outputs,and then to correct inaccurate predictive outputs,a feedback regulator is designed.An autotuned weighing factor is introduced to alleviate the computational burden in practical applications and further improve output tracking performance.Closed-loop stability conditions are derived by rigorous analysis.Simulation results are provided to demonstrate the efficacy of the proposed method. 展开更多
关键词 ESTIMATION TECHNIQUE method
下载PDF
Existence and numerical approximation of a solution to frictional contact problem for electro-elastic materials
16
作者 Othman Baiz EL-Hassan Benkhira Rachid Fakhar 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2024年第2期201-219,共19页
In this paper,a frictional contact problem between an electro-elastic body and an electrically conductive foundation is studied.The contact is modeled by normal compliance with finite penetration and a version of Coul... In this paper,a frictional contact problem between an electro-elastic body and an electrically conductive foundation is studied.The contact is modeled by normal compliance with finite penetration and a version of Coulomb’s law of dry friction in which the coefficient of friction depends on the slip.In addition,the effects of the electrical conductivity of the foundation are taken into account.This model leads to a coupled system of the quasi-variational inequality of the elliptic type for the displacement and the nonlinear variational equation for the electric potential.The existence of a weak solution is proved by using an abstract result for elliptic variational inequalities and a fixed point argument.Then,a finite element approximation of the problem is presented.Under some regularity conditions,an optimal order error estimate of the approximate solution is derived.Finally,a successive iteration technique is used to solve the problem numerically and a convergence result is established. 展开更多
关键词 piezoelectric material frictional contact variational Inequality fixed point process finite element method error estimation iteration method
下载PDF
A robust triaxial localization method of AE source using refraction path
17
作者 Yichao Rui Jie Chen +4 位作者 Jiongkun Chen Jiadong Qiu Zilong Zhou Wenzhong Wang Jinyang Fan 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第4期521-530,共10页
Acoustic emission(AE)localization algorithms based on homogeneous media or single-velocity are less accurate when applied to the triaxial localization experiments.To the end,a robust triaxial localization method of AE... Acoustic emission(AE)localization algorithms based on homogeneous media or single-velocity are less accurate when applied to the triaxial localization experiments.To the end,a robust triaxial localization method of AE source using refraction path is proposed.Firstly,the control equation of the refraction path is established according to the sensor coordinates and arrival times.Secondly,considering the influence of time-difference-of-arrival(TDOA)errors,the residual of the governing equation is calculated to estimate the equation weight.Thirdly,the refraction points in different directions are solved using Snell’s law and orthogonal constraints.Finally,the source coordinates are iteratively solved by weighted correction terms.The feasibility and accuracy of the proposed method are verified by pencil-lead breaking experiments.The simulation results show that the new method is almost unaffected by the refraction ratio,and always holds more stable and accurate positioning performance than the traditional method under different ratios and scales of TDOA outliers. 展开更多
关键词 Acoustic emission(AE) Source localization Robust method Refraction paths Weight estimations
下载PDF
Optimized NPK fertilizer recommendations based on topsoil available nutrient criteria for wheat in drylands of China
18
作者 Wenjie Yang Jie Yu +9 位作者 Yanhang Li Bingli Jia Longgang Jiang Aijing Yuan Yue Ma Ming Huang Hanbing Cao Jinshan Liu Weihong Qiu Zhaohui Wang 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第7期2421-2433,共13页
The optimized management of crop fertilization is very important for improving crop yield and reducing the consumption of chemical fertilizers.Critical nutrient values can be used for evaluating the nutritional status... The optimized management of crop fertilization is very important for improving crop yield and reducing the consumption of chemical fertilizers.Critical nutrient values can be used for evaluating the nutritional status of a crop,and they reflect the nutrient concentrations above which the plant is sufficiently supplied for achieving the maximum potential yield.Based on on-farm surveys of 504 farmers and 60 field experimental sites in the drylands of China,we proposed a recommended fertilization method to determine nitrogen(N),phosphorus(P),and potassium(K)fertilizer input rates for wheat production,and then validated the method by a field experiment at 66 different sites in northern China.The results showed that wheat grain yield varied from 1.1 to 9.2 t ha^(-1),averaging 4.6 t ha^(-1),and it had a quadratic relationship with the topsoil(0-20 cm)nitrate N and soil available P contents at harvest.However,yield was not correlated with the inputs of N,P,and K fertilizers.Based on the relationship(exponential decay model)between 95–105%of the relative yield and topsoil nitrate N,available P,and available K contents at wheat harvest from 60 field experiments,the topsoil critical nutrient values were determined as 34.6,15.6,and 150 mg kg^(-1)for soil nitrate N,available P,and available K,respectively.Then,based on five groups of relative yield(>125%,115–125%,105–115%,95–105%,and<95%)and the model,the five groups of topsoil critical nutrient levels and fertilization coefficients(Fc)were determined.Finally,we proposed a new method for calculating the recommended fertilizer input rate as:Fr=Gy×Nr×Fc,where Fr is the recommended fertilizer(N/P/K)input rate;Gy is the potential grain yield;Nr is the N(N_(rN)),P(N_(rP)),and K(N_(rK))nutrient requirements for wheat to produce 1,000 kg of grain;and Fc is a coefficient for N(N_c)/P(P_c)/K(K_c)fertilizer.A 2-year validated experiment confirmed that the new method reduced N fertilizer input by 17.5%(38.5 kg N ha^(-1))and P fertilizer input by 43.5%(57.5 kg P_(2)O_(5) ha^(-1))in northern China and did not reduce the wheat yield.This outcome can significantly increase the farmers’benefits(by 7.58%,or 139 US$ha^(-1)).Therefore,this new recommended fertilization method can be used as a tool to guide N,P,and K fertilizer application rates for dryland wheat production. 展开更多
关键词 fertilization method dryland wheat soil nutrient critical value soil nitrogen topsoil nutrients
下载PDF
The First Global Map of Atmospheric Ammonia(NH_(3)) as Observed by the HIRAS/FY-3D Satellite
19
作者 Minqiang ZHOU Zhili DENG +6 位作者 Charles ROBERT Xingying ZHANG Lu ZHANG Yapeng WANG Chengli QI Pucai WANG Martine De MAZIÈRE 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第3期379-390,共12页
Atmospheric ammonia(NH_(3)) is a chemically active trace gas that plays an important role in the atmospheric environment and climate change. Satellite remote sensing is a powerful technique to monitor NH_(3) concentra... Atmospheric ammonia(NH_(3)) is a chemically active trace gas that plays an important role in the atmospheric environment and climate change. Satellite remote sensing is a powerful technique to monitor NH_(3) concentration based on the absorption lines of NH_(3) in the thermal infrared region. In this study, we establish a retrieval algorithm to derive the NH_(3)column from the Hyperspectral Infrared Atmospheric Sounder(HIRAS) onboard the Chinese Feng Yun(FY)-3D satellite and present the first atmospheric NH_(3) column global map observed by the HIRAS instrument. The HIRAS observations can well capture NH_(3) hotspots around the world, e.g., India, West Africa, and East China, where large NH_(3) emissions exist. The HIRAS NH_(3) columns are also compared to the space-based Infrared Atmospheric Sounding Interferometer(IASI)measurements, and we find that the two instruments observe a consistent NH_(3) global distribution, with correlation coefficient(R) values of 0.28–0.73. Finally, some remaining issues about the HIRAS NH_(3) retrieval are discussed. 展开更多
关键词 AMMONIA HIRAS/FY-3D satellite thermal-infrared observation remote sensing optimal estimation method
下载PDF
Wavelet Multi-Resolution Interpolation Galerkin Method for Linear Singularly Perturbed Boundary Value Problems
20
作者 Jiaqun Wang Guanxu Pan +1 位作者 Youhe Zhou Xiaojing Liu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第4期297-318,共22页
In this study,a wavelet multi-resolution interpolation Galerkin method(WMIGM)is proposed to solve linear singularly perturbed boundary value problems.Unlike conventional wavelet schemes,the proposed algorithm can be r... In this study,a wavelet multi-resolution interpolation Galerkin method(WMIGM)is proposed to solve linear singularly perturbed boundary value problems.Unlike conventional wavelet schemes,the proposed algorithm can be readily extended to special node generation techniques,such as the Shishkin node.Such a wavelet method allows a high degree of local refinement of the nodal distribution to efficiently capture localized steep gradients.All the shape functions possess the Kronecker delta property,making the imposition of boundary conditions as easy as that in the finite element method.Four numerical examples are studied to demonstrate the validity and accuracy of the proposedwavelet method.The results showthat the use ofmodified Shishkin nodes can significantly reduce numerical oscillation near the boundary layer.Compared with many other methods,the proposed method possesses satisfactory accuracy and efficiency.The theoretical and numerical results demonstrate that the order of theε-uniform convergence of this wavelet method can reach 5. 展开更多
关键词 Wavelet multi-resolution interpolation Galerkin singularly perturbed boundary value problems mesh-free method Shishkin node boundary layer
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部