期刊文献+
共找到93,408篇文章
< 1 2 250 >
每页显示 20 50 100
Calculating models on surface tension of RE_2O_3-Mg O-SiO_2(RE=La, Nd, Sm, Gd and Y) melts 被引量:2
1
作者 吴铖川 成国光 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第11期3696-3701,共6页
A thermodynamic model was developed for determining the surface tension of RE2O3-MgO-SiO2(RE=La, Nd, Sm, Gd and Y) melts considering the ionic radii of the components and Butler's equation. The temperature and com... A thermodynamic model was developed for determining the surface tension of RE2O3-MgO-SiO2(RE=La, Nd, Sm, Gd and Y) melts considering the ionic radii of the components and Butler's equation. The temperature and composition dependence of the surface tensions in molten RE2O3-MgO-SiO2 slag systems was reproduced by the present model using surface tensions and molar volumes of pure oxides, as well as the anionic and cationic radii of the melt components. The iso-surface tension lines of La2O3-MgO-SiO2 slag melt at 1873 K were calculated and the effects of slag composition on the surface tension were also investigated. The surface tensions of La2O3, Gd2O3, Nd2O3 and Y2O3 at 1873 K were evaluated as 686, 677, 664 and 541 m N/m, respectively. The surface tension of pure rare earth oxide melts linearly decreases with increasing cationic field strength, except for Y2O3 oxide, while Y2O3 has a much weaker surface tension. The evaluated results of the surface tension show good agreements with literature data, and the mean deviation of the present model is found to be 1.05% at 1873 K. 展开更多
关键词 rare-earth oxide surface tension ionic radius Butler's equation calculating model
下载PDF
APPLICATION OF WYATT-WHITE METHOD TO CALCULATING INTRINSIC RATES OF INCREASE FOR HYMENOPTEROUS PARASITOIDS
2
作者 况荣平 Sandy M.Smith 《Zoological Research》 CAS CSCD 1993年第3期208-214,共7页
The method developed by Wyatt and White (1977) was applied to calculate the intrinsic rates of increase for parasitoids based on 23 fecundity data sets from the literature. The studies showed that there existed the li... The method developed by Wyatt and White (1977) was applied to calculate the intrinsic rates of increase for parasitoids based on 23 fecundity data sets from the literature. The studies showed that there existed the linear relationship between the accurate values of rm and In f (Md) / d or In (A/d/2) / d, that is, 1) rm= 0.845 In (Md) / d or 2) rm= 0.880 In (Md/ 2) / d. Where d is the prereproductive time, Md is the number of female offspring produced per original female from the first to the dthday of reproduction, and Md/2 is the number of female offspring produced per original female from the first to the (d/ 2) th day of reproduction. These equations can provide the accurate estimates of rm for parasitoids in this study. The approach is advantageous because it does not require the construction of detailed fecundity tables for estimating parasitoid rates of increase. Of course, whether these equations are appropriate for the other taxa will need to be further studied. 展开更多
关键词 PARASITOID Intrinsic rate of increase calculation
下载PDF
Calculating Method for Influence of Material Flow on Energy Consumption in Steel Manufacturing Process 被引量:8
3
作者 YU Qing-bo LU Zhong-wu CAI Jiu-ju 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2007年第2期46-51,共6页
From the viewpoint of systems energy conservation, the influences of material flow on its energy consumption in a steel manufacturing process is an important subject. The quantitative analysis of the relationship betw... From the viewpoint of systems energy conservation, the influences of material flow on its energy consumption in a steel manufacturing process is an important subject. The quantitative analysis of the relationship between material flow and the energy intensity is useful to save energy in steel industry. Based on the concept of standard material flow diagram, all possible situations of ferric material flow in steel manufacturing process are analyzed. The expressions of the influence of material flow deviated from standard material flow diagram on energy consumption are put forward. 展开更多
关键词 steel manufacturing process material flow energy consumption calculating method
下载PDF
NEW METHODS FOR CALCULATING ACTIVITIES OF COMPONENTS FROM PHASE DIAGRAMS IN BINARY PERITECTIC SYSTEMS 被引量:2
4
作者 Zhang, Yongjun Zhang, Xunying Fu, Chongyue 《中国有色金属学会会刊:英文版》 EI CSCD 1997年第2期48-54,共7页
NEWMETHODSFORCALCULATINGACTIVITIESOFCOMPONENTSFROMPHASEDIAGRAMSINBINARYPERITECTICSYSTEMS①ZhangYongjunHunanSu... NEWMETHODSFORCALCULATINGACTIVITIESOFCOMPONENTSFROMPHASEDIAGRAMSINBINARYPERITECTICSYSTEMS①ZhangYongjunHunanSuperiorTechMateri... 展开更多
关键词 THERMODYNAMICS phase DIAGRAMS activity calculation BINARY PERITECTIC SYSTEMS
下载PDF
Hyperbolic Fibonacci and Lucas Functions, “Golden” Fibonacci Goniometry, Bodnar’s Geometry, and Hilbert’s Fourth Problem—Part II. A New Geometric Theory of Phyllotaxis (Bodnar’s Geometry) 被引量:2
5
作者 Alexey Stakhov Samuil Aranson 《Applied Mathematics》 2011年第2期181-188,共8页
This article refers to the “Mathematics of Harmony” by Alexey Stakhov in 2009, a new interdisciplinary direction of modern science. The main goal of the article is to describe two modern scientific discoveries–New ... This article refers to the “Mathematics of Harmony” by Alexey Stakhov in 2009, a new interdisciplinary direction of modern science. The main goal of the article is to describe two modern scientific discoveries–New Geometric Theory of Phyllotaxis (Bodnar’s Geometry) and Hilbert’s Fourth Problem based on the Hyperbolic Fibonacci and Lucas Functions and “Golden” Fibonacci λ-Goniometry (λ > 0 is a given positive real number). Although these discoveries refer to different areas of science (mathematics and theoretical botany), however they are based on one and the same scientific ideas-the “golden mean,” which had been introduced by Euclid in his Elements, and its generalization—the “metallic means,” which have been studied recently by Argentinian mathematician Vera Spinadel. The article is a confirmation of interdisciplinary character of the “Mathematics of Harmony”, which originates from Euclid’s Elements. 展开更多
关键词 Euclid’s Fifth Postulate Lobachevski’s geometry HYPERBOLIC geometry PHYLLOTAXIS Bodnar’s geometry Hilbert’s Fourth Problem The “Golden” and “Metallic” Means Binet Formukas HYPERBOLIC FIBONACCI and Lucas Functions Gazale Formulas “Golden” FIBONACCI λ-Goniometry
下载PDF
The Calculating Model of Structural Analysis for Jack-Up Rig Legs 被引量:1
6
作者 Gu Guowei and Huang Youqing Senier Engineer, China Ofishore Oil Development & Engineering Corporation, (CNOOC), Zhanajiang 524057 China Offshore Oil Development & Engineering Corporation, (CNOOC), Zhanajiang 524057 《China Ocean Engineering》 SCIE EI 1993年第4期409-416,共8页
The selection or establishment of structural calculating model is a matter of primary importance in structural analysis. By analysing the irrationality of the calculating models used by some research organizations at ... The selection or establishment of structural calculating model is a matter of primary importance in structural analysis. By analysing the irrationality of the calculating models used by some research organizations at home and abroad in structural analyses for truss jack-up rig legs, this paper introduces a new calculation model which is more reasonable. This model can simulate better the load situation of a rig reflecting more precisely the effects of the leg loads caused by the spring support of gearboxes of the jacking system and the secondary bending moment raised by hull displacement under extreme conditions. The rig conversion was completed in 1989. In July 1991 the rig safely stood the frontal hitting of Typhoon with the wind speed of 52 m / s, which shows that the checking on the structure is correct. 展开更多
关键词 JACK-UP LEG CONVERSION calculating model PLATFORM
下载PDF
Research on spatial calculating analysis model of landuse change 被引量:5
7
作者 张新长 潘琼 赵元 《Journal of Geographical Sciences》 SCIE CSCD 2004年第3期359-365,共7页
The spatial calculating analysis model is based on GIS overlay. It will compartmentalize the land in research district into three spatial types: unchanged parts, converted parts and increased parts. By this method we ... The spatial calculating analysis model is based on GIS overlay. It will compartmentalize the land in research district into three spatial types: unchanged parts, converted parts and increased parts. By this method we can evaluate the numerical model and dynamic degree model for calculating land-use change rates. Furthermore, the paper raises the possibility of revising the calculating analysis model of spatial information in order to predicate more precisely the dynamic changing level of all types of land uses. In the most concrete terms, the model is used mainly to understand changed area and changed rates (increasing or decreasing) of different land types from microcosmic angle and establish spatial distribution and spatio-temporal principles of the changing urban lands. And we will try to find out why the situation can take place by combining social and economic situations. The result indicates the calculating analysis model of spatial information can derive more accurate procedure of spatial transference and increase of all kinds of land from microcosmic angle. By this model and technology we can conduct the research of land-use spatio-temporal structure evolution more systematically and more deeply, and can obtain a satisfactory result. The result will benefit the rational planning and management of urban land use of developed coastal areas in China in the future. 展开更多
关键词 land use dynamic change spatial calculating analysis model
下载PDF
First-principles calculations of 5d atoms doped hexagonal-AlN sheets: Geometry, magnetic property and the influence of symmetry and symmetry-breaking on the electronic structure 被引量:2
8
作者 汤富领 刘冉 +4 位作者 薛红涛 路文江 冯煜东 芮执元 黄敏 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第1期324-329,共6页
The geometry, electronic structure and magnetic property of the hexagonal AlN(h-AlN) sheet doped by 5d atoms(Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au and Hg) are investigated by first-principles calculations based on the den... The geometry, electronic structure and magnetic property of the hexagonal AlN(h-AlN) sheet doped by 5d atoms(Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au and Hg) are investigated by first-principles calculations based on the density functional theory. The influence of symmetry and symmetry-breaking is also studied. There are two types of local symmetries of the doped systems: C3v and D3h. The symmetry will deviate from exact C3v and D3h for some particular dopants after optimization. The total magnetic moments of the doped systems are 0μBfor Lu, Ta and Ir; 1μB for Hf, W, Pt and Hg; 2μB for Re and Au; and 3μB for Os and Al-vacancy. The total densities of state are presented, where impurity energy levels exist. The impurity energy levels and total magnetic moments can be explained by the splitting of 5d orbitals or molecular orbitals under different symmetries. 展开更多
关键词 hexagonal-AlN sheet first-principles calculations 5d atoms symmetry and symmetry-breaking
下载PDF
N-Calculator与NUFER耦合模型和组合预测法在食物氮足迹研究中的应用
9
作者 乔森 赵骏廷 郑洪波 《安全与环境学报》 CAS CSCD 北大核心 2024年第2期778-786,共9页
为改善传统N-Calculator模型的局限性,加强食物氮足迹核算结果与环境影响的联系,提高活性氮管理预见性,将N-Calculator模型与食物系统养分流动(Nutrient Flows in Food Chains,Environment and Resources Use,NUFER)模型进行耦合,以估... 为改善传统N-Calculator模型的局限性,加强食物氮足迹核算结果与环境影响的联系,提高活性氮管理预见性,将N-Calculator模型与食物系统养分流动(Nutrient Flows in Food Chains,Environment and Resources Use,NUFER)模型进行耦合,以估算我国2001—2020年人均食物氮足迹,建立组合预测体系。结果显示:2001—2020年,我国人均食物氮足迹由16.04 kg N/a增至18.95 kg N/a;全国食物氮足迹由20.47 Mt N/a增至26.76 Mt N/a;居民饮食结构正由以植物源食物为主的低氮消费模式转向以动物源食物为主的高氮消费模式;食物生产过程产生的活性氮的最终归宿为大气(64.3%)、水体和深层土壤(35.7%);我国食物氮足迹与人均可支配收入、城市化率、动物源食物消费氮占比呈正相关性,与恩格尔系数呈负相关性;未来10 a我国人均食物氮足迹呈增长趋势,预测结果显示年均增幅为0.16 kg N/a。 展开更多
关键词 环境学 食物氮足迹 活性氮 N-calculator模型 NUFER模型 组合预测模型
下载PDF
Method of branch ariflow for calculatinga complicated mine ventilation networks 被引量:1
10
作者 刘泽功 《Journal of Coal Science & Engineering(China)》 2001年第1期64-69,共6页
The solutions widely used at present for calculating complicated mine ventilation networks are ones in which resistance of the branches and characteristic parameters of the fans are taken as basic input data. But it i... The solutions widely used at present for calculating complicated mine ventilation networks are ones in which resistance of the branches and characteristic parameters of the fans are taken as basic input data. But it is time and energy consuming to obtain the branch resistance values. A new solution is developed in this paper in which the branch resistance values are obtained through measuring and evaluating the airflow of the whole ventilation network. Theoretical analysis is made of the establishment of a linear equation series with branch resistance as unknown numbers, an equation series for which one, and only one, result of solutions exists. This solution is programmed in C language and passed on a personal computer. The programmed solution programmed proves of practical use, as demonstrated by specific examples. Being different from other solutions, the method takes the branch airflow and fan working points as basic input data, and the present solution is of greater advantage for calculating ventilation networks of mines in operation. 展开更多
关键词 air resistance MEASUREMENTS calculATION COMPUTERS
下载PDF
Fuzzy recognition of missile borne multi-line array infrared detection based on size calculating 被引量:2
11
作者 Bing-shan Lei Jing Li +1 位作者 Wei-na Hao Ke-ding Yan 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2021年第4期1135-1142,共8页
In order to improve the infrared detection and discrimination ability of the smart munition to the dynamic armor target under the complex background,the multi-line array infrared detection system is established based ... In order to improve the infrared detection and discrimination ability of the smart munition to the dynamic armor target under the complex background,the multi-line array infrared detection system is established based on the combination of the single unit infrared detector.The surface dimension features of ground armored targets are identified by size calculating solution algorithm.The signal response value and the value of size calculating are identified by the method of fuzzy recognition to make the fuzzy classification judgment for armored target.According to the characteristics of the target signal,a custom threshold de-noising function is proposed to solve the problem of signal preprocessing.The multi-line array infrared detection can complete the scanning detection in a large area in a short time with the characteristics of smart munition in the steady-state scanning stage.The method solves the disadvantages of wide scanning interval and low detection probability of single unit infrared detection.By reducing the scanning interval,the number of random rendezvous in the infrared feature area of the upper surface is increased,the accuracy of the size calculating is guaranteed.The experiments results show that in the fuzzy recognition method,the size calculating is introduced as the feature operator,which can improve the recognition ability of the ground armor target with different shape size. 展开更多
关键词 Multi-line array infrared detection Size calculating Custom threshold de-noising Fuzzy comprehensive discrimination algorithm
下载PDF
A methodology for calculating the passenger comfort benefits of railway travel 被引量:2
12
作者 Wencheng Huang Bin Shuai 《Journal of Modern Transportation》 2018年第2期107-118,共12页
A comfortable environment in railway passenger coaches can be regarded as a resource for social consumption during the transport process. Railway passenger comfort benefits (RPCBs) can be regarded as a special gener... A comfortable environment in railway passenger coaches can be regarded as a resource for social consumption during the transport process. Railway passenger comfort benefits (RPCBs) can be regarded as a special generalized cost. In this paper, we select a series of objective and subjective indexes to formulate a quantitative method of calculating the RPCB with considering ticket fares. This method includes three steps: make the initial data dimensionless, calculate the weight of each index, and finally calculate the RPCBs. The proposed method was validated with the data collected from two types of trains: G13 from Beijing South to Shanghai Hongqiao and T109 from Beijing to Shanghai. Also, questionnaire survey was conducted in both trains. After data processing, the results show that there is a linear relationship between the RPCB and ticket fare with a correlation coefficient of 0.9616. 展开更多
关键词 Railway transportation economy Comfortbenefit Quantitative calculation Passenger ticket fares Two-phase AHP
下载PDF
A General Calculating Method of Rotor’s Torsional Stiffness Based on Stiffness Influence Coefficient 被引量:1
13
作者 Danmei Xie Wangfan Li +3 位作者 Ling Yang Yong Qian Xianbo Zhao Zhigang Gao 《Engineering(科研)》 2010年第9期698-704,共7页
In order to develop a general calculating rotor’s torsional stiffness based on stiffness influence coefficient for different rotor assembling, the calculation method of the torsional stiffness influence coefficient o... In order to develop a general calculating rotor’s torsional stiffness based on stiffness influence coefficient for different rotor assembling, the calculation method of the torsional stiffness influence coefficient of equal thickness disc is researched in this paper at first. Then the torsional stiffness influence coefficient λ of equal thickness disc is fit to a binary curved face and a calculation equation is obtained based on a large quantity of calculating data, which lays the foundation for research on a general calculating method of rotor torsional stiffness. Thirdly a simplified calculation method for equivalent stiffness diameter of stepped equal thickness disc and cone disc in the steam turbine generators is suggested. Finally a general calculating program for calculating rotor’s torsional vibration features is developed, and the torsional vibration features of a verity of steam turbine rotors are calculated for verification. The calculating results show that stiffness influence coefficient λ of equal-thickness disc depends on parameters of B and H, as well as the stiffness influence coefficient λ;and discs with complex structure can be simplified to equal-thickness discs with little error by using the method suggested in this paper;error can be controlled within 1% when equivalent diameter of stiffness is calculated by this method. 展开更多
关键词 ROTOR DISC GENERAL calculating Method Torsional STIFFNESS STIFFNESS Influence COEFFICIENT
下载PDF
Determine the Stress Calculating Mode of Sliding Failure of Soil Mass under the Push-Extend Multi-under-Reamed Pile 被引量:1
14
作者 Yongmei Qian Xuezhe Chen Xuewen Xie 《Engineering(科研)》 2014年第5期254-259,共6页
Through the analysis of the sliding failure form of soil mass under the bearing push-extend reamed of Push-extend Multi-under-reamed Pile, in the paper, the law of coulomb-Mohr is used to establish a stress function a... Through the analysis of the sliding failure form of soil mass under the bearing push-extend reamed of Push-extend Multi-under-reamed Pile, in the paper, the law of coulomb-Mohr is used to establish a stress function and the theory of the sliding line is used to establish Prandtl regional stress field, which determines the stress calculating mode of soil mass and provides a theoretical basis for a further study of this type of pile ultimate bearing capacity of soil mass. 展开更多
关键词 The Push-Extend Multi-under-Reamed Pile Sliding Failure the Bearing Push-Extend REAMED calculating MODE
下载PDF
FULLERENE GEOMETRY PREDICTION WITH MOLECULAR MECHANICS CALCULATIONS
15
作者 Ming Dan CHEN 《Chinese Chemical Letters》 SCIE CAS CSCD 1993年第2期149-152,共4页
A serial of fullerenes had been built and the optimized geome- tries had been obtained with the energy minimization of molecular mechanics calculations according to the fact that the pentagonal number is exactly 12 in... A serial of fullerenes had been built and the optimized geome- tries had been obtained with the energy minimization of molecular mechanics calculations according to the fact that the pentagonal number is exactly 12 in the fullerenes which consist of pentagons and hexagons.The fullerene geometry prediction could facilitate further theoretical and synthetical studies in the near future. 展开更多
关键词 FULLERENE geometry PREDICTION WITH MOLECULAR MECHANICS calculATIONS THAN
下载PDF
Density functional calculation of equilibrium geometry and electronic structure of pyrite
16
作者 邱冠周 肖奇 +1 位作者 胡岳华 徐竞 《中国有色金属学会会刊:英文版》 CSCD 2001年第4期583-586,共4页
The equilibrium geometry and electronic structure of pyrite has been studied using self consistent density functional theory within the local density approximation (LDA). The optimum bulk geometry is in good agreement... The equilibrium geometry and electronic structure of pyrite has been studied using self consistent density functional theory within the local density approximation (LDA). The optimum bulk geometry is in good agreement with crystallographic data. The calculated band structure and density of states in the region around the Fermi energy show that valence band maximum (VBM) is at X (100), and the conduction band minimum (CBM) is at G (000). The indirect and direct band gaps are 0.6?eV and 0.74?eV, respectively. The calculated contour map of difference of charge density shows excess charge in nonbonding d electron states on the Fe sites. The density increases between sulfur nuclei and between iron and sulfur nuclei qualitatively reveal that S-S bond and Fe-S bond are covalent binding. 展开更多
关键词 density functional calculation electronic structure equilibrium geometry PYRITE
下载PDF
Fractal Geometry:Axioms,Fractal Derivative and Its Geometrical Meaning 被引量:1
17
作者 V.K.Balkhanov 《Journal of Environmental & Earth Sciences》 2019年第1期1-5,共5页
Physics success is largely determined by using mathematics.Physics often themselves create the necessary mathematical apparatus.This article shows how you can construct a fractal calculus-mathematics of fractal geomet... Physics success is largely determined by using mathematics.Physics often themselves create the necessary mathematical apparatus.This article shows how you can construct a fractal calculus-mathematics of fractal geometry.In modem scientific literature often write from a firm that"there is no strict definition of fractals",to the more moderate that"objects in a certain sense,fractal and similar."We show that fractal geometry is a strict mathematical theory,defined by their axioms.This methodology allows the geometry of axiomatised naturally define fractal integrals and differentials.Consistent application on your input below the axiom gives the opportunity to develop effective methods of measurement of fractal dimension,geometri-cal interpretation of fractal derivative gain and open dual symmetry. 展开更多
关键词 FRACTAL geometry FRACTAL dimension FRACTAL calculUS DUALITY
下载PDF
A CALCULATING METHOD OF THE KILL PROBABILITY ATTACK AREA FOR AAM 被引量:1
18
作者 Li Ting-jie, Liu Run-quan and Wang Chao-zhiBeijing University of Aeronautics and Astronautics Zhu Gu-xiang and Wang Li-zhen014 Center of Ministry of Aeronautics and Astronautics 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 1991年第4期339-346,共8页
This paper provides a calculating method which can be used in calculation of the kill probability attack area for every AAM. At first, attack area of AAM and kill probability of every characteristic point are obtained... This paper provides a calculating method which can be used in calculation of the kill probability attack area for every AAM. At first, attack area of AAM and kill probability of every characteristic point are obtained by combining trajectory calculation with kill probability calculation. Then, coordinates of a fire point relative to standard kill probability value in terms of standardization method are found. At last, equivalent kill probability curve equations are formulated by means of curve fitting method. 展开更多
关键词 A calculating METHOD OF THE KILL PROBABILITY ATTACK AREA FOR AAM area
下载PDF
The Method of Calculating Average Skidding Distance
19
作者 张志贤 冯志丽 《Journal of Forestry Research》 SCIE CAS CSCD 1997年第1期47-49,共3页
By analyzing the existing average skidding distance formulac and the shape of the landing area, theauthors put forward that the average skidding distance is the shortest when the ratio of length and width is 1, and th... By analyzing the existing average skidding distance formulac and the shape of the landing area, theauthors put forward that the average skidding distance is the shortest when the ratio of length and width is 1, and the landing collectioll area is in proportion to of average geometrical skidding distance. The new models of calculating average distance are presented. 展开更多
关键词 AVERAGE DISTANCE calculATION METHOD Loggingarea
下载PDF
The Geometry, Vibrational Frequencies and Thermodynamic Properties of Naphthalene Based on ab initio Calculation
20
作者 肖继梅 贡雪东 +1 位作者 肖鹤鸣 丘应楠 《分子科学学报》 CAS CSCD 1998年第3期50-55,共6页
采用abinitio方法,在HF/631G水平下计算了萘的几何构型和振动频率.计算所得几何构型和转动惯量与实验结果相符良好.计算所得振动频率平均比实验结果大9.5%左右;经校正(校正系数0.905)的计算频率与实... 采用abinitio方法,在HF/631G水平下计算了萘的几何构型和振动频率.计算所得几何构型和转动惯量与实验结果相符良好.计算所得振动频率平均比实验结果大9.5%左右;经校正(校正系数0.905)的计算频率与实验结果很接近.用校正后的频率计算所得不同温度下的热力学性质如标准熵、标准热容等与实验结果相吻合. 展开更多
关键词 abinitio法 分子几何构型 振动频率 热力学性质
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部