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红外光谱曲线分峰拟合程序的编写 被引量:11
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作者 徐怡庄 李维红 +5 位作者 彭卿 许振华 翁诗甫 宋增福 吴瑾光 徐光宪 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 1997年第1期55-61,共7页
我们用C语言开发出了用于解决谱带重叠问题的光谱分峰曲线拟合的Curvefit软件,并为程序配备了多种功能和一个友好的人机交互界面以方便使用。经试用表明,该软件无论是在运算速度上还是在运算结果的可靠性方面上都是比较令人... 我们用C语言开发出了用于解决谱带重叠问题的光谱分峰曲线拟合的Curvefit软件,并为程序配备了多种功能和一个友好的人机交互界面以方便使用。经试用表明,该软件无论是在运算速度上还是在运算结果的可靠性方面上都是比较令人满意的。 展开更多
关键词 红外光谱 软件 光谱 曲线峰拟
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语文课程性质:探索、反思与重建 被引量:4
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作者 魏本亚 《天津师范大学学报(基础教育版)》 2009年第1期23-27,共5页
语文课程性质的探索经历了四个阶段,四个阶段呈现出明显的分合曲线;支撑语文课程性质的哲学基础也因时代不同而变奏;重建语文课程性质需要回归、整合,而明确语文课程的主体、客体以及主客体之间的联系,课程性质的重建才能变得简约、具体。
关键词 语文课程性质 分合曲线 认知活动 言语自觉 实践过程
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Higher-Dimensional Integrable Systems Arising from Motions of Curves on S^2(R)and S^3(R) 被引量:2
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作者 QU Chang-Zheng LI Yan-Yan 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第10期841-843,共3页
We show that higher-dimensional integrable systems including the (2+1)-dimensional generalized sine-Gordon equation and the (2+1)-dimensional complex mKdV equation are associated with motions of surfaces inducedby end... We show that higher-dimensional integrable systems including the (2+1)-dimensional generalized sine-Gordon equation and the (2+1)-dimensional complex mKdV equation are associated with motions of surfaces inducedby endowing with an extra space variable to the motions of curves on S^2(R) and S^3(R). 展开更多
关键词 higher-dimensional integrable system motion of curve sine-Gordon equation complex mKdV equation
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Statistical Analysis Methods of Fatigue Crack Growth Rate 被引量:1
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作者 张啸尘 谢里阳 +3 位作者 刘建中 张宇 佟安时 马园园 《Transactions of Tianjin University》 EI CAS 2014年第5期322-327,共6页
The standard center-cracked tensile specimens M (T) with different widths made of aluminum alloy were designed for fatigue crack growth rate experiments, and the effect of specimen size on the fatigue crack growth r... The standard center-cracked tensile specimens M (T) with different widths made of aluminum alloy were designed for fatigue crack growth rate experiments, and the effect of specimen size on the fatigue crack growth rate was discussed. The firing equation and the p-da/dN-△K curve of fatigue crack growth rate (with different confidence and reliability levels) were obtained by one-side tolerance factor analysis. In order to reasonably reflect the dispersion of material properties on the fatigue crack growth rate and fatigue crack propagation life, two novel statistical analysis methods were proposed, which can be used to describe the probability distribution of fatigue crack growth rate. Compared with the traditional statistical analysis method of probabilistic fatigue crack growth rate, the fitted curves from the novel statistical analysis methods yield more objective description on the probability distribution of crack growth rate. 展开更多
关键词 probabilistic fatigue crack growth rate CONFIDENCE RELIABILITY p-da/dN-△K curve fitting
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Temperature distribution of the incompletely mixed fluid flowing in the tubes and the unmixed fluid crossing over the tubes 被引量:1
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作者 WANG Jun CHEN Liang-cai +2 位作者 HE Wei FENG Xtao-qiang LIU Wei 《Journal of Energy and Power Engineering》 2007年第1期49-56,共8页
A new model is established to describe heat exchanging of the incompletely mixed fluid flowing in the tubes and the unmixed fluid crossing out of the tubes in the heat-exchangers especially in air cooler. In the model... A new model is established to describe heat exchanging of the incompletely mixed fluid flowing in the tubes and the unmixed fluid crossing out of the tubes in the heat-exchangers especially in air cooler. In the model, a new method of analyzing volume is proposed to develop the temperature distribution equations of the two fluids --tw(x) and ta(X,,7"). With tw(x) and ta (x, ,7), the curves of the temperature distribution of the two fluids can be obtained. Also tw(x) and ta(x,n) can be used to calculate parameters of structure of an air cooler and to improve performances of it. 展开更多
关键词 air cooler heat-exchangers temperature distribution analyzing volume
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Analytical Algorithms for the Blend Ratios by Fibre-bundle Tensile Curves Part I: Typical Tensile Curve and the Strength and Work Methods 被引量:1
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作者 于伟东 POSTLE Ron 严灏景 《Journal of Donghua University(English Edition)》 EI CAS 2004年第2期27-33,共7页
The blend ratio and tensile properties are vital important characteristics of blended fibre bundles. Fibre-bundle tensile behaviour has been measured by means of the Sirolan-Tensor in order to derive a typical specifi... The blend ratio and tensile properties are vital important characteristics of blended fibre bundles. Fibre-bundle tensile behaviour has been measured by means of the Sirolan-Tensor in order to derive a typical specific stress — extension curve. According to the typical tensile curve, the relationships between the blend ratio and the tensile parameters are discussed and established. Two new algorithms, so-called the strength method and the work method, have been developed for the blend-ratio estimation of blended fibre bundles. The relevant blend-ratios and calculations of the two methods are defined in detail. Also, the characteristics have been explained for every calculation and compared to each others. The experimental results show that the blend ratios estimated from the theoretical methods are high coincidence with the measured results. Meanwhile, the specific stress — extension curve of blended fibre bundles depends directly on the blend ratios of the fibre bundles. 展开更多
关键词 fibre bundle blend ratio TENSILE STRESS EXTENSION
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Estimation of Design Sea Ice Thickness with Maximum Entropy Distribution by Particle Swarm Optimization Method 被引量:1
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作者 TAO Shanshan DONG Sheng +1 位作者 WANG Zhifeng JIANG Wensheng 《Journal of Ocean University of China》 SCIE CAS 2016年第3期423-428,共6页
The maximum entropy distribution, which consists of various recognized theoretical distributions, is a better curve to estimate the design thickness of sea ice. Method of moment and empirical curve fitting method are ... The maximum entropy distribution, which consists of various recognized theoretical distributions, is a better curve to estimate the design thickness of sea ice. Method of moment and empirical curve fitting method are common-used parameter estimation methods for maximum entropy distribution. In this study, we propose to use the particle swarm optimization method as a new parameter estimation method for the maximum entropy distribution, which has the advantage to avoid deviation introduced by simplifications made in other methods. We conducted a case study to fit the hindcasted thickness of the sea ice in the Liaodong Bay of Bohai Sea using these three parameter-estimation methods for the maximum entropy distribution. All methods implemented in this study pass the K-S tests at 0.05 significant level. In terms of the average sum of deviation squares, the empirical curve fitting method provides the best fit for the original data, while the method of moment provides the worst. Among all three methods, the particle swarm optimization method predicts the largest thickness of the sea ice for a same return period. As a result, we recommend using the particle swarm optimization method for the maximum entropy distribution for offshore structures mainly influenced by the sea ice in winter, but using the empirical curve fitting method to reduce the cost in the design of temporary and economic buildings. 展开更多
关键词 sea ice thickness maximum entropy distribution particle swarm optimization return period offshore structural de-sign
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Analytical analysis of pullout resistance of the hydraulic expansion rockbolts on a frictionally coupled model 被引量:1
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作者 Sejin KIM Heejung YOUN Kyoungchul KIM 《Journal of Mountain Science》 SCIE CSCD 2016年第12期2249-2259,共11页
This paper proposes an empirical formula to estimate the shear strength of hydraulic expansion rockbolts.The field experimental results were obtained from eleven pullout tests to evaluate the results computed by the p... This paper proposes an empirical formula to estimate the shear strength of hydraulic expansion rockbolts.The field experimental results were obtained from eleven pullout tests to evaluate the results computed by the proposed formula.It was found that shear resistance of hydraulic expansion rockbolts significantly depends on the uniaxial compressive strength and elastic modulus of rock,with high correlation coefficients of 0.7651 and0.8587,respectively.The developed formula enables estimation of the maximum pullout load in an analytical process without pullout tests in the field.Conversely,due to the poor interlocking at the initial pullout load,the measured displacements were higher than the estimated ones.To reduce the interlocking effects between bolt and rock,we recommend preloading of 29.4 kN.Preload allows reducing the distance between the measured and estimated displacement and making two load-displacement curves practically identical with marginal differences of 1.1 to 1.5 mm at the maximum pullout load. 展开更多
关键词 Expansion rockbolt Pullout resistance Pullout load Shear strength
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Target reliability index for serviceability limit state of single piles 被引量:3
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作者 边晓亚 郑俊杰 +1 位作者 徐志军 章荣军 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第1期310-316,共7页
The objective is to develop an approach for the determination of the target reliability index for serviceability limit state(SLS) of single piles. This contributes to conducting the SLS reliability-based design(RBD) o... The objective is to develop an approach for the determination of the target reliability index for serviceability limit state(SLS) of single piles. This contributes to conducting the SLS reliability-based design(RBD) of piles. Based on a two-parameter,hyperbolic curve-fitting equation describing the load-settlement relation of piles, the SLS model factor is defined. Then, taking into account the uncertainties of load-settlement model, load and bearing capacity of piles, the formula for computing the SLS reliability index(βsls) is obtained using the mean value first order second moment(MVFOSM) method. Meanwhile, the limit state function for conducting the SLS reliability analysis by the Monte Carlo simulation(MCS) method is established. These two methods are finally applied to determine the SLS target reliability index. Herein, the limiting tolerable settlement(slt) is treated as a random variable. For illustration, four load test databases from South Africa are compiled again to conduct reliability analysis and present the recommended target reliability indices. The results indicate that the MVFOSM method overestimates βsls compared to that computed by the MCS method. Besides, both factor of safety(FS) and slt are key factors influencing βsls, so the combination of FS and βsls is welcome to be used for the SLS reliability analysis of piles when slt is determined. For smaller slt, pile types and soils conditions have significant influence on the SLS target reliability indices; for larger slt, slt is the major factor having influence on the SLS target reliability indices. This proves that slt is the most key parameter for the determination of the SLS target reliability index. 展开更多
关键词 single pile serviceability limit state target reliability index mean value first order second moment method Monte Carlo simulation
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“Liverscore”is predictive of both liver fi brosis and activity in chronic hepatitis C
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作者 Shoukat Ali Arain Qamar Jamal Amir Omair 《World Journal of Gastroenterology》 SCIE CAS CSCD 2011年第41期4607-4613,共7页
AIM:To formulate a noninvasive index predictive of se-verity of liver f ibrosis and activity in chronic hepatitis C.METHODS:This cross sectional study was conducted on polymerase chain reaction positive,treatment nave... AIM:To formulate a noninvasive index predictive of se-verity of liver f ibrosis and activity in chronic hepatitis C.METHODS:This cross sectional study was conducted on polymerase chain reaction positive,treatment nave patients.Fibrosis was staged on a f ive point scale from F0-F4 and activity was graded on a four point scale from A0-A3,according to the METAVIR system.Patients were divided into two overall severity groups,minimal disease(< F2 and < A2)and signif icant disease(≥ F2 or ≥ A2).Eleven markers were measured in blood.Sta-tistically,the primary outcome variable was identif ica-tion of minimal and signif icant overall disease.Indices were formulated using β regression values of different combinations of nine statistically significant factors.Diagnostic performance of these indices was assessed through receiver-operating characteristic curve analysis.RESULTS:A total of 98 patients were included and of these 46 had an overall clinically significant disease.Our f inal six marker index,Liverscore for Hepatitis C,consisted of age,alanine transaminase,gamma-gluta-myl transpeptidase,apolipoprotein A-1,alpha-2 macro-globulin and hyaluronic acid.The area under the curve was found to be 0.813.On a 0-1 scale,negative predic-tive value at a cutoff level of ≤ 0.40 was 83%,while positive predictive value at ≥ 0.80 remained 89%.Al-together,61% of the patients had these discriminative scores.CONCLUSION:This index is discriminative of minimal and significant overall liver disease in a majority of chronic hepatitis C patients and can help in clinical de-cision making. 展开更多
关键词 Chronic hepatitis C Staging and grading Liver fibrosis and activity Noninvasive assessment Liverscore
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Failure Analysis in Graphite Epoxy Composite Laminates
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作者 Olanrewaju Aluko 《Journal of Mechanics Engineering and Automation》 2014年第10期813-819,共7页
The present analysis was performed to obtain bearing strength for pinned joints in uni-directional graphite epoxy composite laminates using characteristic curve model. The characteristic dimensions used to determine t... The present analysis was performed to obtain bearing strength for pinned joints in uni-directional graphite epoxy composite laminates using characteristic curve model. The characteristic dimensions used to determine the characteristic curve were evaluated using a two-dimensional finite element model that was developed in ANSYS14.5 Software. Also, two-dimensional finite element stress analysis was developed to determine the stress distribution needed to evaluate the failure. Tsai-Wu failure criterion was used in the analysis with the characteristic curve to predict bearing strength. The results of the analysis showed good agreement with experimental data. 展开更多
关键词 Bearing strength COMPOSITE finite element experiment.
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Uncertainty analysis of correlated non-normal geotechnical parameters using Gaussian copula 被引量:10
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作者 LI DianQing TANG XiaoSong +1 位作者 ZHOU ChuangBing PHOON Kok-Kwang 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第11期3081-3089,共9页
Determining the joint probability distribution of correlated non-normal geotechnical parameters based on incomplete statistical data is a challenging problem.This paper proposes a Gaussian copula-based method for mode... Determining the joint probability distribution of correlated non-normal geotechnical parameters based on incomplete statistical data is a challenging problem.This paper proposes a Gaussian copula-based method for modelling the joint probability distribution of bivariate uncertain data.First,the concepts of Pearson and Kendall correlation coefficients are presented,and the copula theory is briefly introduced.Thereafter,a Pearson method and a Kendall method are developed to determine the copula parameter underlying Gaussian copula.Second,these two methods are compared in computational efficiency,applicability,and capability of fitting data.Finally,four load-test datasets of load-displacement curves of piles are used to illustrate the proposed method.The results indicate that the proposed Gaussian copula-based method can not only characterize the correlation between geotechnical parameters,but also construct the joint probability distribution function of correlated non-normal geotechnical parameters in a more general way.It can serve as a general tool to construct the joint probability distribution of correlated geotechnical parameters based on incomplete data.The Gaussian copula using the Kendall method is superior to that using the Pearson method,which should be recommended for modelling and simulating the joint probability distribution of correlated geotechnical parameters.There exists a strong negative correlation between the two parameters underlying load-displacement curves.Neglecting such correlation will not capture the scatter in the measured load-displacement curves.These results substantially extend the application of the copula theory to multivariate simulation in geotechnical engineering. 展开更多
关键词 geotechnical parameters uncertainty analysis joint probability distribution function Gaussian copula Pearson corre-lation coefficient Kendall correlation coefficient load-displacement curve
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New minimal surfaces in the hyperbolic space
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作者 CUI NingWei TENENBLAT Keti 《Science China Mathematics》 SCIE CSCD 2017年第9期1679-1704,共26页
We obtain new complete minimal surfaces in the hyperbolic space H3, by using Ribaucour transformations. Starting with the family of spherical catenoids in H^3 found by Mori(1981), we obtain 2-and 3-parameter families ... We obtain new complete minimal surfaces in the hyperbolic space H3, by using Ribaucour transformations. Starting with the family of spherical catenoids in H^3 found by Mori(1981), we obtain 2-and 3-parameter families of new minimal surfaces in the hyperbolic space, by solving a non trivial integro-differential system. Special choices of the parameters provide minimal surfaces whose parametrizations are defined on connected regions of R^2 minus a disjoint union of Jordan curves. Any connected region bounded by such a Jordan curve, generates a complete minimal surface, whose boundary at infinity of H^3 is a closed curve. The geometric properties of the surfaces regarding the ends, completeness and symmetries are discussed. 展开更多
关键词 minimal surfaces hyperbolic space Ribaucour transformations
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New data processing method for improving the measurement accuracy in FTP 被引量:1
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作者 田静 孙杰 +2 位作者 宁韩利 许中奇 杨明 《Optoelectronics Letters》 EI 2011年第1期69-73,共5页
During the 3D shape measurement,there are noises in the images that are obtained by the capture system.The traditional method,Fourier transform profilometry(FTP) technique,improves the accuracy only by the filtering m... During the 3D shape measurement,there are noises in the images that are obtained by the capture system.The traditional method,Fourier transform profilometry(FTP) technique,improves the accuracy only by the filtering method in the frequency domain.In this paper,the curve fitting method is used for the light field distribution calculation before the filtering process applied in the frequency domain by choosing a suitable filter window,and then the higher quality of the basic frequency component signal is got.This method can avoid the frequency overlapping caused by the noise,so the improvement of the measuring accuracy of FTP is realized. 展开更多
关键词 Curve fitting Data handling Fourier transforms Frequency domain analysis Profilometry Three dimensional
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