期刊文献+
共找到30篇文章
< 1 2 >
每页显示 20 50 100
Yields,growth and water use under chemical topping in relations to row configuration and plant density in drip-irrigated cotton 被引量:1
1
作者 Wang Xuejiao Hu Yanping +10 位作者 Ji Chunrong Chen Yongfan Sun Shuai Zhang Zeshan Zhang Yutong Wang Sen Yang Mingfeng Ji Fen Guo Yanyun Li Jie Zhang Lizhen 《Journal of Cotton Research》 CAS 2024年第2期123-136,共14页
Background Water deficit is an important problem in agricultural production in arid regions.With the advent of wholly mechanized technology for cotton planting in Xinjiang,it is important to determine which planting m... Background Water deficit is an important problem in agricultural production in arid regions.With the advent of wholly mechanized technology for cotton planting in Xinjiang,it is important to determine which planting mode could achieve high yield,fiber quality and water use efficiency(WUE).This study aimed to explore if chemical topping affected cotton yield,quality and water use in relation to row configuration and plant densities.Results Experiments were carried out in Xinjiang China,in 2020 and 2021 with two topping method,manual topping and chemical topping,two plant densities,low and high,and two row configurations,i.e.,76 cm equal rows and 10+66 cm narrow-wide rows,which were commonly applied in matching harvest machine.Chemical topping increased seed cotton yield,but did not affect cotton fiber quality comparing to traditional manual topping.Under equal row spacing,the WUE in higher density was 62.4%higher than in the lower one.However,under narrow-wide row spacing,the WUE in lower density was 53.3%higher than in higher one(farmers’practice).For machine-harvest cotton in Xinjiang,the optimal row configuration and plant density for chemical topping was narrow-wide rows with 15 plants m-2 or equal rows with 18 plants m-2.Conclusion The plant density recommended in narrow-wide rows was less than farmers’practice and the density in equal rows was moderate with local practice.Our results provide new knowledge on optimizing agronomic managements of machine-harvested cotton for both high yield and water efficient. 展开更多
关键词 Yield components Fiber quality TRANSPIratioN Water use efficiency Heat ratio method(HRM)
下载PDF
Estimation of quality factors by energy ratio method 被引量:1
2
作者 王宗俊 曹思远 +5 位作者 张浩然 曲英铭 袁殿 杨金浩 张德龙 邵冠铭 《Applied Geophysics》 SCIE CSCD 2015年第1期86-92,122,123,共9页
The quality factor Q, which reflects the energy attenuation of seismic waves in subsurface media, is a diagnostic tool for hydrocarbon detection and reservoir characterization. In this paper, we propose a new Q extrac... The quality factor Q, which reflects the energy attenuation of seismic waves in subsurface media, is a diagnostic tool for hydrocarbon detection and reservoir characterization. In this paper, we propose a new Q extraction method based on the energy ratio before and after the wavelet attenuation, named the energy-ratio method(ERM). The proposed method uses multipoint signal data in the time domain to estimate the wavelet energy without invoking the source wavelet spectrum, which is necessary in conventional Q extraction methods, and is applicable to any source wavelet spectrum; however, it requires high-precision seismic data. Forward zero-offset VSP modeling suggests that the ERM can be used for reliable Q inversion after nonintrinsic attenuation(geometric dispersion, refl ection, and transmission loss) compensation. The application to real zero-offset VSP data shows that the Q values extracted by the ERM and spectral ratio methods are identical, which proves the reliability of the new method. 展开更多
关键词 Quality factor Q energy ratio time domain seismic wavelet spectral ratio method
下载PDF
Fuzzy distances based FMAGDM compromise ratio method and application 被引量:2
3
作者 Zhenfeng Rui Dengfeng Li 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2010年第3期455-460,共6页
An extended compromise ratio method(CRM) based on fuzzy distances is developed to solve fuzzy multi-attribute group decision making problems in which weights of attributes and ratings of alternatives on attributes a... An extended compromise ratio method(CRM) based on fuzzy distances is developed to solve fuzzy multi-attribute group decision making problems in which weights of attributes and ratings of alternatives on attributes are expressed with values of linguistic variables parameterized using triangular fuzzy numbers.A compromise solution is determined by introducing the ranking index based on the concept that the chosen alternative should be as close as possible to the positive ideal solution and as far away from the negative ideal solution as possible simultaneously.This proposed method is compared with other existing methods to show its feasibility and effectiveness and illustrated with an example of the military route selection problem as one of the possible applications. 展开更多
关键词 fuzzy multi-attribute group decision making(FMAGDM) compromise ratio method(CRM) linguistic variable fuzzy number fuzzy distance.
下载PDF
Identification and analysis of serum samples by surface-enhanced Raman spectroscopy combined with characteristic ratio method and PCA for gastric cancer detection 被引量:2
4
作者 Liu Guo Yuanpeng Li +5 位作者 Furong Huang Jia Dong Fucui Li Xinhao Yang Siqi Zhu Maoxun Yang 《Journal of Innovative Optical Health Sciences》 SCIE EI CAS 2019年第2期13-23,共11页
This study aimed to explore the application of surface-enhanced Raman scattering(SERS)in the rapid diagnosis of gastric cancer.The SERS spectra of 68 serum samples from gastric cancer patients and healthy volunteers w... This study aimed to explore the application of surface-enhanced Raman scattering(SERS)in the rapid diagnosis of gastric cancer.The SERS spectra of 68 serum samples from gastric cancer patients and healthy volunteers were acquired.The characteristic ratio method(CRM)and principal component analysis(PCA)were used to differentiate gastric cancer serum from normal serum.Compared with healthy volunteers,the serum SERS intensity of gastric cancer patients was relatively high at 722 cm^(-1),while it was relatively low at 588,644,861,1008,1235,1397,1445 and 1586 cm^(-1).These results indicated that the relative content of nucleic acids in the serum of gastric cancer patients rises while the relative content of amino acids and carbohydrates decreases.In PCA,the sensitivity and specificity of discriminating gastric cancer were 94.1%and 94.1%,respectively,with the accuracy of 94.1%.Based on the intensity ratios of four characteristic peaks at 722,861,1008 and 1397 cm^(-1),CRM presented the diagnostic sensitivity and specificity of 100%and 97.4%,respectively,and the accuracy of 98.5%.Therefore,the three peak intensity ratios of I_(722)/I_(861),I_(722)/I_(1008)and I_(722)/I_(1397)can be considered as biologicalfingerprint information for gastric cancer diagnosis and can rapidly and directly reflect the physiological and pathological changes associated with gastric cancer development.This study provides an important basis and standards for the early diagnosis of gastric cancer. 展开更多
关键词 Surface-enhanced Raman spectroscopy SERUM gastric cancer characteristic ratio method principal components analysis
下载PDF
Calculation method of sliding ratios for conjugate-curve gear pair and its application 被引量:3
5
作者 梁栋 陈兵奎 高艳娥 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第3期946-955,共10页
The calculation method of sliding ratios for conjugate-curve gear pair, generated based on the theory of conjugate curves,is proposed. The theoretical model of conjugate-curve gear drive is briefly introduced. The gen... The calculation method of sliding ratios for conjugate-curve gear pair, generated based on the theory of conjugate curves,is proposed. The theoretical model of conjugate-curve gear drive is briefly introduced. The general calculation formulas of sliding ratios are developed according to the conjugate curves. The applications to the circular arc gears based on conjugate curves and the novel involute-helix gears are studied. A comparison on the sliding coefficient with the conventional corresponding gear drive is also carried out. The influences of gear parameters such as spiral parameter, gear ratio and modulus on the sliding ratios of gear drive are discussed. Brief description of manufacturing method for conjugate-curve gear pair is given. The research results show that the sliding ratios of gear pair become smaller with the increase of spiral parameter and gear ratio, respectively. And it will be greater with the increase of modulus for the tooth profiles. The meshing characteristics of conjugate-curve gears are further reflected and the optimization design of tooth profiles with high performance may be obtained. 展开更多
关键词 conjugate-curve gear conjugate curve sliding ratio manufacturing method
下载PDF
Design of flying vehicle control system by signal to noise ratio
6
作者 孙龙大 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2001年第1期63-68,共6页
Presents the new concept of ″Desired to be small″ based on the basic function of vehicle flight control system for an optimal design of flying vehicle control system, and the definition of S/N ratio and calculation ... Presents the new concept of ″Desired to be small″ based on the basic function of vehicle flight control system for an optimal design of flying vehicle control system, and the definition of S/N ratio and calculation formula for ″Desired to be small″ dynamic characteristics, and the S/N ratio method established for design of velicle flight control systems, by which, an orthogrnal table is used to arrange test schemes, and error facters are used to simulate various interferences, and the use of S/N ratio as a design criterion to synthesise the design of dynamic and static characteristics for definition of an optimal scheme, the application of S/N ratio method to the design of a type of vehicle control system and the single run success abtained in design of control system, technical evaluation test and design finalization flight test. 展开更多
关键词 S/N ratio method control system dynamic characteristics static characteristics parameter design
下载PDF
Analysis of the Wave Velocity Ratio Anomalies in the Tianshan Region of Xinjiang
7
作者 Zhang Linlin Gao Chaojun 《Earthquake Research in China》 CSCD 2017年第1期39-50,共12页
Based on the seismic observation report data provided by the Xinjiang Digital Seismic Network from 2009 to 2014,we calculate the wave velocity ratio and its background value for medium and small earthquakes by using t... Based on the seismic observation report data provided by the Xinjiang Digital Seismic Network from 2009 to 2014,we calculate the wave velocity ratio and its background value for medium and small earthquakes by using the multi-station method in Tianshan,Xinjiang.This paper analyzes the variation of the wave velocity ratio disturbance value to highlight the abnormal,and also back-traces 7 moderate earthquakes at the research area.The results show that:(1)the background value of the wave velocity ratio is almost 1.70,the wave velocity ratio obviously decreases in the middle-eastern part of Tianshan and the region near the Puchang fault;(2)the wave velocity ratio disturbance value is mostly low in the epicenter before four earthquakes of M≥5.0 from 2011 to 2013 in the study area;(3)before 7 moderate strong earthquakes,the earthquake events with low value of the wave velocity ratio account for over 60% of corresponding total events near the epicenters,and the low value of the wave velocity ratio is relatively obvious before moderate earthquakes. 展开更多
关键词 Seismic observation report Multi-station method The wave velocity ratio disturbance value Tianshan region
下载PDF
Tomographic inversion of near-surface Q factor by combining surface and cross-hole seismic surveys 被引量:9
8
作者 李国发 郑浩 +2 位作者 祝文亮 王明超 翟桐立 《Applied Geophysics》 SCIE CSCD 2016年第1期93-102,219,220,共12页
The estimation of the quality factor Q plays a fundamental role in enhancing seismic resolution via absorption compensation in the near-surface layer.We present a new geometry that can be used to acquire field data by... The estimation of the quality factor Q plays a fundamental role in enhancing seismic resolution via absorption compensation in the near-surface layer.We present a new geometry that can be used to acquire field data by combining surface and cross-hole surveys to decrease the effect of geophone coupling on Q estimation.In this study,we drilled number of receiver holes around the source hole,each hole has different depth and each geophone is placed geophones into the bottom of each receiver hole to avoid the effect of geophone coupling with the borehole wall on Q estimation in conventional cross-hole seismic surveys.We also propose a novel tomographic inversion of the Q factor without the effect of the source signature,and examine its stability and reliability using synthetic data.We estimate the Q factors of the near-surface layer in two different frequency bands using field data acquired in the Dagang Oilfield.The results show that seismic absorption in the nearsurface layer is much greater than that in the subsurface strata.Thus,it is of critical practical importance to enhance the seismic solution by compensating for near-surface absorption.In addition,we derive different Q factors from two frequency bands,which can be treated,to some extent,as evidence of a frequency-dependent Q. 展开更多
关键词 near surface Q factor tomographic inversion spectral ratio method frequency dependence
下载PDF
An analysis of seismic scattering attenuation in a random elastic medium 被引量:2
9
作者 刘炯 魏修成 +4 位作者 季玉新 陈天胜 刘春园 张春涛 戴明刚 《Applied Geophysics》 SCIE CSCD 2011年第4期344-354,372,共12页
Seismic attenuation has been inherent media characteristics in which an interesting topic of research, for it reflects the seismic waves propagate. There are many factors that cause seismic wave attenuation, such as g... Seismic attenuation has been inherent media characteristics in which an interesting topic of research, for it reflects the seismic waves propagate. There are many factors that cause seismic wave attenuation, such as geometry attenuation caused by energy dissipating during propagation, friction attenuation by relative sliding among rock grains, and scattering attenuation by rock heterogeneity. In this paper we study P-wave scattering attenuation in a random elastic medium by numerical simulations from a statistical point of view. A random elastic medium model is built based on general stochastic process theory. Then a staggered-grid pseudo-spectral method is used to simulate wave propagation. Scattering attenuation is estimated by the spectral ratio method based on virtual detector records. Random elastic media numerical scatter results with various heterogeneity levels show that the higher heterogeneous levels cause greater scattering attenuation. When the scatter sizes are smaller than a wave length, the larger scatters give a greater attenuation. Finally, we propose a method to evaluate fluid-flow attenuation in porous media. The fluid- flow attenuation is derived from total attenuation and scattering attenuation in random porous media and the attenuation is estimated quantitatively. Results show that in the real seismic frequency range when the heterogeneous scale is about 10^1 meters (less than one wave length), scattering attenuation is larger than fluid-tlow attenuation in random porous media and scattering attenuation is the main factor of seismic attenuation in real heterogeneous porous media. 展开更多
关键词 scattering attenuation random elastic medium the spectral ratio method
下载PDF
Optimizing data for electrical resistivity tomography in hardened sites through the ratio method
10
作者 Jiang Fuyu Gao Likun +2 位作者 Chen Haijun Ni Jiong Li Fuqiang 《Journal of Southeast University(English Edition)》 EI CAS 2024年第4期372-385,共14页
To reduce the shielding effect of hardened layers on electrical resistivity tomography,a ratio method based on the distortion correction principle and the isolation coefficient is proposed.The effects of the resistivi... To reduce the shielding effect of hardened layers on electrical resistivity tomography,a ratio method based on the distortion correction principle and the isolation coefficient is proposed.The effects of the resistivity and thickness of hardened concrete layers on the detection of target objects are explored.Both numerical simulations and indoor tank tests indicate that when the ratio method is employed to correct the original collected data,the maximum allowable error for the isolation coefficient should not exceed 1%.Notably,when the ratio of hardened layer thickness to electrode spacing does not exceed 1,correction through this method significantly enhances the recognition capability of target objects.However,when the hardened layer thickness is greater than the electrode spacing by a factor of 2 or more,the ratio method cannot achieve satisfactory results.The case study of flood control engineering detection in the Zhangxi section of the Huangpen River in Dongzhi County demonstrates that the detection effect after correction by the ratio method is comparable to that for the adjacent unhardened pavement,and the influence of the hardened layer is obviously weakened,resulting in more reliable results. 展开更多
关键词 ratio method resistivity tomography hardened site distortion principle data optimization
下载PDF
Site response in the Qionghai Basin in the Wenchuan earthquake 被引量:3
11
作者 Wang Haiyun Xie Lili +1 位作者 Wang Suyang Ye Peng 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2013年第2期195-199,共5页
Amplification effects of soil site response can significantly impact ground motions, and must be considered in the seismic fortification of buildings/structures to prevent or mitigate this potential seismic hazard. Ut... Amplification effects of soil site response can significantly impact ground motions, and must be considered in the seismic fortification of buildings/structures to prevent or mitigate this potential seismic hazard. Utilizing acceleration time histories from the main shock of the Wenchuan earthquake recorded at four stations (i.e., one on bedrock and three on soil) in the Qionghai Basin, the site responses from three soil sites are studied by using the traditional spectral ratio method. The bedrock site is selected as a reference site. This study found that peak ground accelerations (PGAs) on the soil sites are much larger than on bedrock, with EW, NS and UD components of 3.96-6.58, 6.27-10.98, and 3.17-6.66 times those of the bedrock site, respectively. The amplification effects of the soil sites on ground motions in the frequency range of 0.1 Hz to 10 Hz are significant, depending on the thickness of the soil layer and the frequency content of the site. A significant amplification occurs with high frequency components of ground motion at shallow soil sites, and low and high frequency components of ground motion at intermediate soil sites. 展开更多
关键词 site response traditional spectral ratio method acceleration time history Qionghai Basin Wenchuan earthquake
下载PDF
Effects of unsymmetrical geometric confinements on depletion interactions in colloidal suspensions 被引量:3
12
作者 郭纪源 黄立新 肖长明 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第7期1638-1644,共7页
The depletion interactions between two large-spheres immersed in a fluid of small spheres under unsymmetrical geometrical confinement are studied through the acceptance ratio method. The numerical results show that no... The depletion interactions between two large-spheres immersed in a fluid of small spheres under unsymmetrical geometrical confinement are studied through the acceptance ratio method. The numerical results show that no matter whether the volume fraction is large or small, both the depletion potential and depletion force are affected by the presence of the two plates; the closer the two large spheres are to the plate, the larger the effects of the unsymmetrical confinements. 展开更多
关键词 depletion interactions COLLOIDAL acceptance ratio method
下载PDF
Prediction of plastic zone size around circular tunnels in non-hydrostatic stress field 被引量:6
13
作者 Behnam Bagheri Fazlollah Soltani Hamid Mohammadi 《International Journal of Mining Science and Technology》 SCIE EI 2014年第1期81-85,共5页
This paper discusses the calculation of plastic zone properties around circular tunnels to rock-masses that satisfy the Hoek–Brown failure criterion in non-hydrostatic condition,and reviews the calculation of plastic... This paper discusses the calculation of plastic zone properties around circular tunnels to rock-masses that satisfy the Hoek–Brown failure criterion in non-hydrostatic condition,and reviews the calculation of plastic zone and displacement,and the basis of the convergence–confinement method in hydrostatic condition.A two-dimensional numerical simulation model was developed to gain understanding of the plastic zone shape.Plastic zone radius in any angles around the tunnel is analyzed and measured,using different values of overburden(four states)and stress ratio(nine states).Plastic zone radius equations were obtained from fitting curve to data which are dependent on the values of stress ratio,angle and plastic zone radius in hydrostatic condition.Finally validation of this equation indicate that results predict the real plastic zone radius appropriately. 展开更多
关键词 Plastic zone radius Convergence-confinement method Non-hydrostatic condition Stress ratio
下载PDF
Seismic ground motion variations resulting from site conditions 被引量:1
14
作者 Silacheva N Kulbayeva U Kravchenko N 《Geodesy and Geodynamics》 2014年第2期9-15,共7页
Amplification of seismic ground motions in the territory of Almaty city is evaluated by using different methods. The pattern and probable causes of ground motion variations in different engineering-geological conditio... Amplification of seismic ground motions in the territory of Almaty city is evaluated by using different methods. The pattern and probable causes of ground motion variations in different engineering-geological conditions are characterized. An expeditious application of these techniques within a complex methodical approach for Almaty city microzonation is considered. 展开更多
关键词 ground motion variations spectral ratio methodical approach
下载PDF
Distribution of Lg coda Q in Xinjiang and its adjacent regions
15
作者 徐彦 毛燕 +2 位作者 胡家富 苏有锦 丛连理 《Acta Seismologica Sinica(English Edition)》 EI CSCD 2005年第2期162-170,254,共10页
In this study, we collected 1156 broadband vertical components records at 22 digital seismic stations in Xinjiang region, Urumqi station, and 7 stations in the adjacent regions during the period of 1999-2003. The reco... In this study, we collected 1156 broadband vertical components records at 22 digital seismic stations in Xinjiang region, Urumqi station, and 7 stations in the adjacent regions during the period of 1999-2003. The records were firstly processed by the stacked spectral ratio method to obtain Q0 (Q at 1 Hz) and the frequency correlation factor η corresponding to each path. Based on the results, the distribution images of Q0 and η in 1°×1° grids for Xinjiang region were gained by the back-projection technique. The results indicate that Q0 is high (300-450) in the Tarim platform and marginal Siberian platform, while Q0 is low (150-250) in the southern regions as west Kunlun fold system and Songpan-Ganzi fold system. In the northern regions as Junggar fold system and Tianshan fold system, Q0 is also low (250-300) and η varies between 0.5 and 0.9. 展开更多
关键词 Lg coda Q stacked spectral ratio method back-projection technique Xinjiang region
下载PDF
Investigation of upper crust anisotropy in Ghaen-Birjand region, east-central Iran
16
作者 Mohammad-Reza Gheitanchi Zoya Zarifii 《Acta Seismologica Sinica(English Edition)》 CSCD 2004年第5期518-525,共8页
A number of aftershocks of the May 10th 1997, Zirkuh (Ghaen-Birjand) destructive earthquake have been used to investigate the anisotropy in the upper crust by observing shear wave splitting. Particle motion diagram an... A number of aftershocks of the May 10th 1997, Zirkuh (Ghaen-Birjand) destructive earthquake have been used to investigate the anisotropy in the upper crust by observing shear wave splitting. Particle motion diagram and aspect ratio methods were used as two different approaches to obtain splitting parameters. Clear shear wave splitting was observed on the records of the selected aftershocks, indicating that the media in the region was highly anisotropic. By using particle motion method, the direction of fast shear wave was found 22°N±19°E, while the delay time between the fast and slow shear waves was obtained to be (65±16) ms. By aspect ratio method, the direction of fast shear wave was determined to be 35°N±18°E and the delay time between fast and slow shear waves was found to be (49±10) ms. For a simple horizontal layer with a thickness about 5 km and uniformly distributed anisotropy, a stress aligned cracks model was used and the result was interpreted in terms of vertical aligned cracks in the direction of N22°E, having a density about 0.01. It is assumed that cracks are fluid-filled since they are located in the upper crust. Finally, by using Hudson cracks model for three crack densities 0.005, 0.01, 0.03, the velocity curves of shear wave were plotted as a function of angle between the symmetrical axis of cracks and the azimuth of source to receiver. It was concluded that when shear wave was polarized parallel to the crack surface, the velocity was uniform, but the velocity curve varied clearly if shear wave was polarized perpendicular to the crack surface. 展开更多
关键词 shear wave splitting anisotropy in upper crust Hudson cracks model particle motion diagram aspect ratio method Zirkuh (Ghaen-Birjand) earthquake active faults aftershock activity
下载PDF
Improved Approach Based on SVM for License Plate Character Recognition
17
作者 王晓华 王晓光 《Journal of Beijing Institute of Technology》 EI CAS 2005年第4期378-381,共4页
An improved approach based on support vector machine (SVM) called the center distance ratio method is presented for license plate character recognition. First the support vectors are pre-extraeted. A minimal set cal... An improved approach based on support vector machine (SVM) called the center distance ratio method is presented for license plate character recognition. First the support vectors are pre-extraeted. A minimal set called the margin vector set, which contains all support vectors, is extracted. These margin vectors compose new training data and construct the classifier by using the general SVM optimized. The experimental resuhs show that the improved SVM method does well at correct rate and training speed. 展开更多
关键词 support vector machine(SVM) center distance ratio method margin vector support vector character recognition
下载PDF
Depletion interactions in binary mixtures of repulsive colloids
18
作者 李卫华 邱枫 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第10期623-631,共9页
Acceptance ratio method, which has been used to calculate the depletion potential in binary hard-sphere mixtures, is extended to the computation of the depletion potential of non-rigid particle systems. The repulsive ... Acceptance ratio method, which has been used to calculate the depletion potential in binary hard-sphere mixtures, is extended to the computation of the depletion potential of non-rigid particle systems. The repulsive part of the Lennard-Jones pair potential is used as the direct pair potential between the non-rigid particles. The depletion potential between two big spheres immersed in a suspension of small spheres is determined with the acceptance ratio method through the application of Monte Carlo simulation. In order to check the validity of this method, our results are compared with those obtained by the Asakura-Oosawa approximation, and by Varial expansion approach, and by molecular dynamics simulation. The total effective potential and the depth of its potential well are computed for various softness parameters of the direct pair potential. 展开更多
关键词 acceptance ratio method Monte Carlo depletion interaction
下载PDF
Improved Support Vector Machine Approach Based on Determining Thresholds Automatically
19
作者 王晓华 闫雪梅 王晓光 《Journal of Beijing Institute of Technology》 EI CAS 2007年第3期300-304,共5页
To improve the training speed of support vector machine (SVM), a method called improved center distance ratio method (ICDRM) with determining thresholds automatically is presented here without reduce the identific... To improve the training speed of support vector machine (SVM), a method called improved center distance ratio method (ICDRM) with determining thresholds automatically is presented here without reduce the identification rate. In this method border vectors are chosen from the given samples by comparing sample vectors with center distance ratio in advance. The number of training samples is reduced greatly and the training speed is improved. This method is used to the identification for license plate characters. Experimental resuhs show that the improved SVM method-ICDRM does well at identification rate and training speed. 展开更多
关键词 support vector machine (SVM) improved center distance ratio method (ICDRM) THRESHOLD border vector
下载PDF
Complex of Copper(Ⅱ) with 1, 4, 9, 12-Tetraaza Cyclo-2, 3, 6, 7, 10, 14, 15-Tetrabenzocetanan-5, 8, 13, 16-Tetraone by Spectrophotometry
20
作者 Zunli Mo 《Rare Metals》 SCIE EI CAS CSCD 2001年第1期24-27,共4页
The spectrophotometric characteristic of a new reagent 1, 4, 9, 12-tetraaza Cyclo-2, 3, 6, 7, 10, 11, 14, 15 tetrabenzocetanan-5, 8, 13, 16-tetraone (TCTCT) and its complex with Cu(Ⅱ) were studied. The reagent and i... The spectrophotometric characteristic of a new reagent 1, 4, 9, 12-tetraaza Cyclo-2, 3, 6, 7, 10, 11, 14, 15 tetrabenzocetanan-5, 8, 13, 16-tetraone (TCTCT) and its complex with Cu(Ⅱ) were studied. The reagent and its complex with Cu(Ⅱ) have a similar maximum absorbance at 446 um. In C6H4(C2O4HK)-NaOH buffer (pH=4.00), the complex of Cu(Ⅱ)-TCTCT formed when it was heated. The absorbance increased with the increase of the concentration of Cu(Ⅱ) in the range of 1 .6x10-7-5.5x 10-5 mol/L. The composition ratio of the complex was formed to be 1: 1 using the molar ratio method. The method was simple, rapid and sensitive, giving an apparent molar absorptivity of 1.25x105 L mol-1 cm-1 and the apparent stability constant of 1 .04x106. The method was directly applied of copper in fresh milk. 展开更多
关键词 complex of Cu (Ⅱ) reagent TCTCT molar ratio method
下载PDF
上一页 1 2 下一页 到第
使用帮助 返回顶部