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    题名 作者 年代 出处 被引量
1LAGFD-WAM numerical wave model-Ⅰ. Basic physical model显示文摘The LAGFD-WAM wave model is a third generation wave model. In the present paper the physical aspect of the model was shown in great detail including energy spectrum balance equation, complicated characteristics equations and source functions.Yuan Yeli, Hua Feng, Pan Zengdi Sun Letao First Institute of Oceanography, State Oceanic Administration, Qingdao 266003, China 1991Acta Oceanologica Sinica1991,10,4:46
2Dynamical Framework of IAP Nine-Level Atmospheric General Circulation Model显示文摘The dynamical framework of the nine-level version of the IAP AGCM is presented in this paper. The emphasis of the model’s description is put on the following two aspects:(1) A model’s standard atmosphere, which is a satisfactory approximation to the observed troposphere and lower stratosphere standard atmosphere, is introduced into the equations of the model to permit a more accurate calculation of the vertical transport terms, especially near the tropopause; (2) The vertical levels of the model are carefully selected to guarantee a smooth dependence of layer thickness upon pressure in order to reduce the truncation error involved in the unequal interval vertical finite-differencing. For testing the model, two kinds of linear baroclinic Rossby-Haurwitz waves, one of which has a dynamically stable vertical structure and the other has a relatively unstable one, are constructed to provide initial conditions for numerical experiments. The two waves have been integrated for more than 300 days and 100 days张学洪 1990Advances in Atmospheric Sciences1990,7,1:48
3Simulation analysis and match experiment on negative and positive pressures of pneumatic precision metering device for rapeseed显示文摘Positive and negative pressures determine the performance of pneumatic precision metering device for rapeseed.In order to investigate the relationship between positive and negative pressures of nozzles,fluid models of chamber were developed to simulate the airflow,and the k-εturbulence model was conducted to capture the pressure and velocity of nozzles.Through these efforts linear models were achieved.Meanwhile,the three-factor factorial split-split experiment was designed with negative pressure,positive pressure and the rotating speeds varying from-1000 to-4500 Pa,50 to 250 Pa and 10 to 45 r/min,respectively.The mathematical models were developed through employing the stepwise regression method.The sequence of influential factors on the quality of feed index was positive pressure,negative pressure and rotating speed.To obtain the match regulation of negative and positive pressures with“good”performance,the ratio coefficient K of negative and positive pressures was introduced to build mathematical models.Models relating ratio coefficient K with positive pressure were fitted in different rotating speeds.The results showed that the ratio coefficient was matchedГ∈[f1(x),f2(x)]from the fitting equations with the rotating speed of 10-30 r/min;while the rotating speed has greater influence when it was 35-40 r/min and the setsΛ∈[g1(x),g2(x)]were achieved,where x∈[100,250].This study could be conducted to adjust the rotating speed of the pneumatic system to optimize the ideal performance of the seeder.Yu Jiajia Liao Yitao Cong Jinling Yang Song Liao Qingxi 2014International Journal of Agricultural and Biological Engineering2014,7,3:21
4Study on the Relation between Garment Style and Ease Distribution显示文摘The shape of body and the ease of garment are the important elements in constructing garment style. However, the distribution of ease in garment is uneven and the curves showing different cross-sections of garment style with ease are unavailable in the literature. This information is crucial when the three-dimensional garment style is transformed into two-dimensional garment patterns. Thus, several different X-line style garments are produced by 3D draping technology, and the cubic spline is used to fit the cross sectional curves of BL, WL of body and garment. By comparing cross sections of body and garment, the ease at different location can be derived. Besides, garments in 10 different dimensions and quantities of style ease are included in the current study. By numerical operation on discrete ease data at different location, the fitted functions of ease distribution are obtained.王朝晖 张渭源 2004Journal of Donghua University(English Edition)2004,21,6:12
5The Convergence of Least-Squares Progressive Iterative Approximation for Singular Least-Squares Fitting System显示文摘Data fitting is an extensively employed modeling tool in geometric design. With the advent of the big data era, the data sets to be fitted are made larger and larger, leading to more and more least-squares fitting systems with singular coefficient matrices. LSPIA (least-squares progressive iterative approximation) is an efficient iterative method for the least-squares fitting. However, the convergence of LSPIA for the singular least-squares fitting systems remains as an open problem. In this paper, the authors showed that LSPIA for the singular least-squares fitting systems is convergent. Moreover, in a special case, LSPIA converges to the Moore-Penrose (M-P) pseudo-inverse solution to the least- squares fitting result of the data set. This property makes LSPIA, an iterative method with clear geometric meanings, robust in geometric modeling applications. In addition, the authors discussed some implementation detail of LSPIA, and presented an example to validate the convergence of LSPIA for the singular least-squares fitting systems.LIN Hongwei CAO Qi ZHANG Xiaoting 2018Journal of Systems Science & Complexity2018,31,6:11
6On solubility and supersolubility of some classes of finite groups显示文摘Let G be a finite group and H a subgroup of G. Then H is said to be S-permutable in G if HP = PH for all Sylow subgroups P of G. Let HsG be the subgroup of H generated by all those subgroups of H which are S-permutable in G. Then we say that H is S-embedded in G if G has a normal subgroup T and an S-permutable subgroup C such that T ∩ H HsG and HT = C. Our main result is the following Theorem A. A group G is supersoluble if and only if for every non-cyclic Sylow subgroup P of the generalized Fitting subgroup F*(G) of G, at least one of the following holds: (1) Every maximal subgroup of P is S-embedded in G. (2) Every cyclic subgroup H of P with prime order or order 4 (if P is a non-abelian 2-group and H Z∞(G)) is S-embedded in G.SHUM Kar Ping SKIBA Alexander N. 2009Science China Mathematics2009,52,2:10
7Improved form of wind wave frequency spectrum显示文摘The lower frequency part of the theoretical wind wave spectrum proposed by the authors (Wen et al. , 1988a, b,c) has been improved and the form of spectrum is appreciably simplified. In addition to the field data collected in the Bohai Sea region and used in the previous papers, those obtained in the Huanghai Sea, the East China Sea and the South China Sea have been employed so that the improved spectra can be verified on a more extensive observational basis. Computed results agree with the observations well. Further comparisons have been made between the proposed spectra and the JONSWAP spectrum. Though the two types of spectrum are close to each other in form, the former shows, as a whole, better agreement with the observation than the latter. By introducing an improved relation between the peak-ness factor and significant wave steepness, the spectrum contains only significant wave height and period as parameters. For spectra given in this form, the computed peak frequencies coincide approximatelyWen Shengchang (S. C. Wen ), Zhang Dacuo, Guo Peifang, Wang Wei, Chen Bohai and Tai Weitao Institute of Physical Oceanography, Ocean University of Qingdao, China 1989Acta Oceanologica Sinica1989,8,4:10
8Automatic image segmentation method for cotton leaves with disease under natural environment显示文摘In order to improve the image segmentation performance of cotton leaves in natural environment, an automatic segmentation model of diseased leaf with active gradient and local information is proposed. Firstly, a segmented monotone decreasing edge composite function is proposed to accelerate the evolution of the level set curve in the gradient smooth region. Secondly, canny edge detection operator gradient is introduced into the model as the global information. In the process of the evolution of the level set function, the guidance information of the energy function is used to guide the curve evolution according to the local information of the image, and the smooth contour curve is obtained. And the main direction of the evolution of the level set curve is controlled according to the global gradient information, which effectively overcomes the local minima in the process of the evolution of the level set function. Finally, the Heaviside function is introduced into the energy function to smooth the contours of the motion and to increase the penalty function Φ(x) to calibrate the deviation of the level set function so that the level set is smooth and closed. The results showed that the model of cotton leaf edge profile curve could be obtained in the model of cotton leaf covered by bare soil, straw mulching and plastic film mulching, and the ideal edge of the ROI could be realized when the light was not uniform. In the complex background, the model can segment the leaves of the cotton with uneven illumination, shadow and weed background, and it is better to realize the ideal extraction of the edge of the blade. Compared with the Geodesic Active Contour(GAC) algorithm, Chan-Vese(C-V) algorithm and Local Binary Fitting(LBF) algorithm, it is found that the model has the advantages of segmentation accuracy and running time when processing seven kinds of cotton disease leaves images, including uneven lighting, leaf disease spot blur, adhesive diseased leaf, shadow, complex background, unclear diseased leaf edges, and staggered condition. This model can not only conduct image segmentation of cotton leaves under natural conditions, but also provide technical support for the accurate identification and diagnosis of cotton diseases.ZHANG Jian-hua KONG Fan-tao WU Jian-zhai HAN Shu-qing ZHAI Zhi-fen 2018Journal of Integrative Agriculture2018,17,8:9
9The Influence of Minimal Subgroups on the Structure of Finite GroupsYanming Wang Mathematics Department,Zhongshan University,Guangzhou 510275,P.R.China 2000Acta Mathematica Sinica,English Series2000,16,1:8
10Methane adsorption behavior on coal having different pore structures显示文摘The adsorption of methane onto five dry coal samples was measured at 298 K over the pressure range from 0 to 3.5 MPa using a volumetric method.The isotherm data were fitted to the Langmuir and the Freundlich equations.The kinetic data were fitted to a pseudo second order equation,the linear driving force equation(LDF),and an intra-particle diffusion model.These results showed that higher methane adsorption is correlated with larger micro-pore volumes and specific surface areas.The adsorption was related to the narrow micro-pore size distribution when the previous two parameters are large.The kinetics study showed that the kinetics of methane adsorption onto these five dry coal samples followed a pseudo second order model very well.Methane adsorption rates are controlled by intra-particle diffusion.The faster the intra-particle diffusion,the faster the methane adsorption rate will be.Zhao Yi Jiang Chengfa Chu Wei 2012International Journal of Mining Science and Technology2012,22,6:7
11An intelligent SVM modeling process for crude oil properties prediction based on a hybrid GA-PSO method显示文摘Properties prediction of crude oil remains an essential issue for refineries. In this communication, an exhaustive and extendable support vector machine(SVM) intelligent prediction process has been proposed to solve this problem. A novel hybrid genetic algorithm-particle swarm optimization(GA-PSO)method was applied to optimize the SVM model. The optimization process and result demonstrated that the newly proposed GA-PSO-SVM method was more accurate and time-saving than the classical GA or PSO method. Compared with the classical Grid-search SVM, the combined GA-PSO-SVM model appeared to be more applicable for the properties prediction task. The TBP distillation curve fitting was exampled to evaluate the performance of the developed model. The regression result demonstrated the high accuracy and efficiency of the proposed process. The model can be applied in the Industrial Internet as a plugin, and the adaptability and flexibility is demonstrated by the implement of crude oil molecular reconstruction employing the intelligent prediction process.Kexin Bi Tong Qiu 2019Chinese Journal of Chemical Engineering2019,27,8:6
12The Theoretical Analysis of Multi-wavelength Pyrometer:Check and Autosearch for Emissivity General Expression显示文摘In general, the dependence of the logarithm of the emissivity upon wavelength is usually used in the treatment of data measured by multi-wavelength pyrometer. In this paper, the suitability of this expression for different materials has been examined. Further more, an effective method for automatically searching the mathematical model between emissivity and wavelength has been procsed. The calculated results show that the accuracy is improved by using this data treatment method.孙晓刚 徐文辉 褚载祥 1998Journal of Harbin Institute of Technology(New Series)1998,5,3:6
13INTRACLOUD LIGHTNING DISCHARGES IN THE LOWER PART OF THUNDERCLOUD显示文摘From analysis of observational data of thunderstorms in Gansu,China,it was deduced that the electricstructure of thunderclouds in this region is often positive charge in the upper,main negative in the middlelayer and another positive charge,large in magnitude and extensive in dimension,in the lower part.Intra-cloud discharges often take place between the main negative charge and lower positive charge instead of upper.Case analysis of 6 intracloud discharges in two storms on August 3 and 4,1986 shows that the centers of thesedischarges and the dipole moments destroyed were at the altitude of 3.8—6 km msl(7.6—-13.5℃)and 18—40 C km,respectively.刘欣生 叶宗秀 邵选民 王才伟 言穆弘 郭昌明 1989Acta meteorologica Sinica1989,3,2:6
14Robust inversion analysis of local gravity anomalies caused by geological dislocation model of faults显示文摘RobustinversionanalysisoflocalgravityanomaliescausedbygeologicaldislocationmodeloffaultsJIANLIANGHUANG(黄建梁)CHONGYANGSHEN(申...黄建梁 申重阳 李辉 1998Acta Seismologica Sinica(English Edition)1998,11,1:5
15A derivation of the generalized Korf growth equation and its application显示文摘Based on the biological hypothesis of tree growth, the generafized Korf growth equation, was derived theoretically. From a standpoint of applications, the equation can be used in two ways associated with the power exponent of p, and stwo types of growth equations: the Korf-A (P> 1 ) and the Korf-B (0< p <1) were developed and between them, there is the Gompertz equation (P = 1) to separate each other. All of the three types of equations are independent. It was conduded that the Korf-A equation could be used to describe the growth of trees, of which inflection point is between O and A/e, while the Korf-B equation with the inffection point between A/e and A could be applied to describe the biological population growth. It was found that the Korf-A equation had a better property in describing the growth process of a tree or a stand and its applications to predicting height growth and stand self-thinning showed general good fitness.李凤日 赵宝东 苏贵林 2000Journal of Forestry Research2000,11,2:5
16Splitting and Merging Based Multi-model Fitting for Point Cloud Segmentation显示文摘This paper deals with the massive point cloud segmentation processing technology on the basis of machine vision, which is the second essential factor for the intelligent data processing of three dimensional conformation in digital photogrammetry. In this paper, multi-model fitting method is used to segment the point cloud according to the spatial distribution and spatial geometric structure of point clouds by fitting the point cloud into different geometric primitives models. Because point cloud usually possesses large amount of 3D points, which are uneven distributed over various complex structures, this paper proposes a point cloud segmentation method based on multi-model fitting. Firstly, the pre-segmentation of point cloud is conducted by using the clustering method based on density distribution. And then the follow fitting and segmentation are carried out by using the multi-model fitting method based on split and merging. For the plane and the arc surface, this paper uses different fitting methods, and finally realizing the indoor dense point cloud segmentation. The experimental results show that this method can achieve the automatic segmentation of the point cloud without setting the number of models in advance. Compared with the existing point cloud segmentation methods, this method has obvious advantages in segmentation effect and time cost, and can achieve higher segmentation accuracy. After processed by method proposed in this paper, the point cloud even with large-scale and complex structures can often be segmented into 3D geometric elements with finer and accurate model parameters, which can give rise to an accurate 3D conformation.Liangpei ZHANG Yun ZHANG Zhenzhong CHEN Peipei XIAO Bin LUO 2019Journal of Geodesy and Geoinformation Science2019,2,2:5
17Check of free oscillation signal with SG data显示文摘The observation of the Earth’s free oscillation is an important way to study the Earth’s inner structure and geophysical parameters. Many geophysicists have investigated the Earth’s normal modes with strainmeters and spring gravimeters. Since the superconducting gravimeters appeared, people have gained a new kind of more stable instruments to detect the normal modes. The measurement for the Earth’s free oscillation with the superconducting gravimeters is one of the main goals of the Global Geodynamics Project. In this note, we have investigated the Earth’s normal modes excited by Peru Ms 7.9 Earthquake on June 23, 2001 with the superconducting gravimeter C032 at the Wuhan station. After having completed the subtraction of gravity tides with the 20th order polynomial fitting, and the correction for pressure and the analysis of the noise spectrum of the superconducting gravimeter, we accurately observed all base normal modes from 0S0 to 0S32 and the splittings of 0S2 and 0S3. Those results show a goodXiang’e Lei Houze Xu Heping Sun 2002Chinese Science Bulletin2002,47,18:4
18An Aridity Trend in China and Its Abrupt Feature in Association with the Global Warming显示文摘A distinct aridity trend in China in last 100 years is presented by applying a linear fitting to both the climate records and the hydrological records, which is supported by evidence of environmental changes and seems to be associated with a global warming trend during this period.The Mann Kendall Rank statistic test reveals a very interesting feature that the climate of China entered into a dry regime abruptly in about 1920’s, which synchronized with the rapid warming of the global temperature at almost the same time.According to an analysis of the meridional profile of observed global zonal mean precipitation anomalies during the peak period of global wanning (1930-1940), the drought occurred in whole middle latitude zone (25°N-55°N) of the Northern Hemisphere, where the most part of China is located in. Although this pattern is in good agreement with the latitude distribution of the difference of zonal mean rates of precipitation between 4 × CO2 and 1 × CO2 simulated by climate model (Manabe符淙斌 1993Advances in Atmospheric Sciences1993,10,1:4
19A general, fast and robust B-spline fitting scheme for micro-line tool path under chord error constraint显示文摘The discontinuity of linear tool path(or G01 blocks) brings about unnecessary feedrate deceleration and fluctuation during machining. To improve the continuity, the linear tool path is usually smoothed by the local transition method or the global fitting method. For micro-line tool path, the transition method will significantly decrease the machining efficiency and introduce feedrate fluctuation. The global fitting method cannot be directly used in the NC interpolation because the indispensable chord error checking and iterative fitting processes are computation-intensive. This paper presents a general, fast and robust B-spline fitting scheme under chord error constraint for high speed interpolation of micro-line tool path. The proposed fitting method guarantees the chord error by utilizing the strong convex hull property of B-spline curves. The knot vector and control points are initially generated by a progressive iterative approximation method and locally refined to conform to the chord error constraint by using an analytical method. The analytical approximation and refining methods avoid solving a linear system of equations that is necessary in the standard B-spline fitting method. The feasibility and efficiency of the proposed scheme has been verified via simulations and experiments. Compared with the traditional fitting method, the proposed scheme can strictly constrain the chord error and can significantly decrease the computational load. Compared with the transition scheme, the proposed scheme can significantly increase the machining efficiency for the same micro-line tool path under the same chord error tolerance.BI QingZhen HUANG Jie LU YaoAn ZHU LiMin DING Han 2019Science China(Technological Sciences)2019,62,2:4
20Many-knot spline technique for approximation of data显示文摘A class of new fundamental functions with compact support called many-knot spline is introduced. The two-scale relation for the fundamental functions is investigated, and the higher order accuracy spline approximation scheme is constructed by using the available degrees of freedom which come from additional knots. The technique has been efficiently applied to the problems such as time-frequency analysis, computer aided geometric design, and digital signal processing.齐东旭 李华山 1999Science China(Technological Sciences)1999,42,4:4
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