期刊文献+
共找到14篇文章
< 1 >
每页显示 20 50 100
实验室小样抄造法分析湿造法纤维滤材的过滤性能
1
作者 贾瑞清 王炉平 吴雪平 《机床与液压》 北大核心 2000年第4期100-101,90,共3页
关键词 湿造纤维滤材 力学性能 实验室小样抄造
下载PDF
第一铬矿小样取样法
2
《铬盐工业》 1996年第F04期7-22,共16页
关键词 铬矿 取样 人工取样 机械取样 国际标准 小样取样
下载PDF
油棕基因组DNA 3种提取方法的比较研究 被引量:8
3
作者 周丽霞 肖勇 +1 位作者 杨耀东 马子龙 《江西农业学报》 CAS 2013年第8期9-11,共3页
采用CTAB小样提取法、PVP法和SDS-CTAB改良法,分别从油棕嫩叶和老叶中提取基因组DNA,并通过紫外分光光度计、琼脂糖凝胶电泳和PCR反应进行检测。研究结果表明:用CTAB小样提取法提取的油棕嫩叶总DNA的质量最好,纯度最高;用其他2种方法提... 采用CTAB小样提取法、PVP法和SDS-CTAB改良法,分别从油棕嫩叶和老叶中提取基因组DNA,并通过紫外分光光度计、琼脂糖凝胶电泳和PCR反应进行检测。研究结果表明:用CTAB小样提取法提取的油棕嫩叶总DNA的质量最好,纯度最高;用其他2种方法提取的DNA的质量均较差。 展开更多
关键词 油棕 基因组DNA 提取 CTAB小样提取 PVP SDS-CTAB改良
下载PDF
楠木人工林优树选择标准和方法 被引量:15
4
作者 陈祖松 《福建林业科技》 北大核心 1999年第2期29-33,共5页
本文分别应用小样地法、平均木标准差对比法、综合评分法、优势木对比法对4株预选树(nm-20、nm-19、nm-18、nm-06)进行分析,制定选优标准,确定nm-20为优树。分析结果表明:应用小样地法进行楠木人工林选... 本文分别应用小样地法、平均木标准差对比法、综合评分法、优势木对比法对4株预选树(nm-20、nm-19、nm-18、nm-06)进行分析,制定选优标准,确定nm-20为优树。分析结果表明:应用小样地法进行楠木人工林选优最客观、正确,工作量较少。若预选树生长量指标md>40%、mh>30%、mv>140%且形质指标符合,则可确定为优树。 展开更多
关键词 楠木 优树 选择标准 小样
下载PDF
复合材料防弹板性能小样本分析 被引量:3
5
作者 张佐光 沈建明 +1 位作者 李敏 孙志杰 《北京航空航天大学学报》 EI CAS CSCD 北大核心 2003年第6期561-564,共4页
二维配对升降法小样本统计分析方法可在较少的试验量下 ,获得高可靠度的结果 .在靶试数据基础上运用该统计方法 ,推导出三种复合材料防弹板在确定置信度和一定穿透率下的临界穿透速度、最小全穿透速度和最大不穿透速度 ,以及一定未穿透... 二维配对升降法小样本统计分析方法可在较少的试验量下 ,获得高可靠度的结果 .在靶试数据基础上运用该统计方法 ,推导出三种复合材料防弹板在确定置信度和一定穿透率下的临界穿透速度、最小全穿透速度和最大不穿透速度 ,以及一定未穿透概率下的临界面密度 . 展开更多
关键词 装甲 复合材料 置信水平 临界穿透速度 小样本二维配对升降
下载PDF
针织物在标准大气中单位面积质量的试验方法 被引量:1
6
作者 刘智德 《天津纺织科技》 2022年第3期41-44,共4页
当前尚无关于针织物在标准大气中测定其单位面积质量的国内标准。文中选用常见的针织物,包括平纹布、罗纹布、双面布、毛圈布、毛衫布等,在标准大气中调湿一段时间后,用小样法测定单位面积质量。结果表明,此方法操作快捷、效率高,符合... 当前尚无关于针织物在标准大气中测定其单位面积质量的国内标准。文中选用常见的针织物,包括平纹布、罗纹布、双面布、毛圈布、毛衫布等,在标准大气中调湿一段时间后,用小样法测定单位面积质量。结果表明,此方法操作快捷、效率高,符合客户的要求。 展开更多
关键词 针织物 标准大气 单位面积质量 调湿 小样法
下载PDF
Data-driven methods for predicting the representative temperature of bridge cable based on limited measured data
7
作者 WANG Fen DAI Gong-lian +2 位作者 HE Chang-lin GE Hao RAO Hui-ming 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第9期3168-3186,共19页
Cable-stayed bridges have been widely used in high-speed railway infrastructure.The accurate determination of cable’s representative temperatures is vital during the intricate processes of design,construction,and mai... Cable-stayed bridges have been widely used in high-speed railway infrastructure.The accurate determination of cable’s representative temperatures is vital during the intricate processes of design,construction,and maintenance of cable-stayed bridges.However,the representative temperatures of stayed cables are not specified in the existing design codes.To address this issue,this study investigates the distribution of the cable temperature and determinates its representative temperature.First,an experimental investigation,spanning over a period of one year,was carried out near the bridge site to obtain the temperature data.According to the statistical analysis of the measured data,it reveals that the temperature distribution is generally uniform along the cable cross-section without significant temperature gradient.Then,based on the limited data,the Monte Carlo,the gradient boosted regression trees(GBRT),and univariate linear regression(ULR)methods are employed to predict the cable’s representative temperature throughout the service life.These methods effectively overcome the limitations of insufficient monitoring data and accurately predict the representative temperature of the cables.However,each method has its own advantages and limitations in terms of applicability and accuracy.A comprehensive evaluation of the performance of these methods is conducted,and practical recommendations are provided for their application.The proposed methods and representative temperatures provide a good basis for the operation and maintenance of in-service long-span cable-stayed bridges. 展开更多
关键词 cable-stayed bridges representative temperature gradient boosted regression trees(GBRT)method field test limited measured data
下载PDF
对森林经理调查几种方法的思考
8
作者 刘永强 仇洪林 《黑龙江林业》 2002年第8期19-19,共1页
关键词 森林经理调查 森林经营 样地控制 小样圆分层抽样 航空样片判读
下载PDF
Notes on the Scaling Function 被引量:2
9
作者 WUHua-an ZHANGGui-zhen 《Chinese Quarterly Journal of Mathematics》 CSCD 2004年第2期188-191,共4页
Two properties are given in this paper about the scaling function: suppose Vj; j ∈ Z is a multiresolution analysis with a continuous scaling function φ which have compact support set and that φ the Fourier transfor... Two properties are given in this paper about the scaling function: suppose Vj; j ∈ Z is a multiresolution analysis with a continuous scaling function φ which have compact support set and that φ the Fourier transform of φ is a continuous real function, compactly supported, then φ(0) ≠ 0 and when supp φ = [a1,b1]∪[a2,b2](b1 < a2,0 < a2), then we havea1 ≤ 0, 0 < b1, a1 < b2/2 ≤ b1, 2π < b2 - a1 ≤ 8π. 展开更多
关键词 multiresolution analysis scaling function Fourier transform
下载PDF
Investigation of Image Fusion Between High-Resolution Image and Multi-spectral Image 被引量:1
10
作者 LI Pingxiang WANG ZhijunLI Pingxiang, professor, State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, 129 Luoyu Road, Wuhan 430079, China. 《Geo-Spatial Information Science》 2003年第2期31-34,共4页
On the basis of a thorough understanding of the physical characteristics of remote sensing image, this paper employs the theories of wavelet transform and signal sampling to develop a new image fusion algorithm. The a... On the basis of a thorough understanding of the physical characteristics of remote sensing image, this paper employs the theories of wavelet transform and signal sampling to develop a new image fusion algorithm. The algorithm has been successfully applied to the image fusion of SPOT PAN and TM of Guangdong province, China. The experimental results show that a perfect image fusion can be built up by using the image analytical solution and re-construction in the image frequency domain based on the physical characteristics of the image formation. The method has demonstrated that the results of the image fusion do not change spectral characteristics of the original image. 展开更多
关键词 image fusion remote sensing wavelet transform signal sampling
下载PDF
Bayesian Method Reliability of Flight Simulator
11
作者 WANG Li XIONG Jing 《International English Education Research》 2017年第1期76-78,共3页
This paper introduces the basic viewpoints and characteristics of Bayesian statistics. Which provides a theoretical basis for solving the problem of small sample of flight simulator using Bayesian method. A series of ... This paper introduces the basic viewpoints and characteristics of Bayesian statistics. Which provides a theoretical basis for solving the problem of small sample of flight simulator using Bayesian method. A series of formulas were derived to establish the Bayesian reliability modeling and evaluation model for flight simulation equipment. The two key problems of Bayesian method were pointed out as follows: obtaining the prior distribution of WeibuU parameter, calculating the parameter a posterior distribution and parameter estimation without analytic solution, and proposing the corresponding solution scheme. 展开更多
关键词 Small sample data Flight simulation equipment Reliability modeling Bayesian method Weibull parameter
下载PDF
Soil Properties Degradation Assessment Using Infrared Scanning Technique of Soils (Case Study: Eastern of Congo)
12
作者 Bashagaluke Janvier Mulumuna Janvier +6 位作者 Pieter Pypers Walangululu Jean Shepherd Keith MochogeBenson Mugwe Jayne Vanlauwe Bernard Boeckx Pascal 《Journal of Agricultural Science and Technology(A)》 2013年第9期677-688,共12页
Recently, near infrared reflectance (NIR) and mid-infrared (MIR) spectroscopy techniques are increasingly introduced as convenient and simple non-destructive techniques for quantifying several soil properties. Thi... Recently, near infrared reflectance (NIR) and mid-infrared (MIR) spectroscopy techniques are increasingly introduced as convenient and simple non-destructive techniques for quantifying several soil properties. This study uses MIR method to predict pH, soil organic C, total N, AI, Ca, Mg and K, CEC and soil texture for soil samples collected in Sud-Kivu, Congo. A total of 536 composite soil samples were taken from two locations (Burhale and Luhihi) at two depths (0-20 cm and 20-40 cm) using a spatially-stratified random sampling design within an area of 200 km2. Differences in characteristics were evaluated between the two locations, land use (cultivated vs. non-cultivated land) with soil depths. A random subset of the samples (10%) were analyzed using standard wet chemistry methods, and calibration models developed by MIR data to estimate soil properties for the full soil sample set. Partial least squares regression (PLS) method gave acceptable coefficients of determination between 0.71 and 0.93 for all parameters. Soil organic matter levels were higher in cultivated plots in Luhihi (3.9% C) than in Burhale (3.0% C), suggesting lower levels of soil fertility in the later area. This indicates high levels of acidity, which are likely to limit crop production in the area. Phosphorus deficiency is acute in Burhale (2.4 mg P/kg) but less in Luhihi (5.4 mg P/kg). In both locations, low levels of Ca and Mg indicate that soils may be susceptible to deficiencies in both elements.These findings provide new opportunities for monitoring soil quality in the region which can benefit multiple actors and scientists involved in the agricultural and environmental sectors. 展开更多
关键词 Parameter DEPTH infrared correlation prediction landuse.
下载PDF
Learning rates of regularized regression on the unit sphere 被引量:2
13
作者 CAO FeiLong LIN ShaoBo +1 位作者 CHANG XiangYu XU ZongBen 《Science China Mathematics》 SCIE 2013年第4期861-876,共16页
This paper addresses the learning algorithm on the unit sphere.The main purpose is to present an error analysis for regression generated by regularized least square algorithms with spherical harmonics kernel.The exces... This paper addresses the learning algorithm on the unit sphere.The main purpose is to present an error analysis for regression generated by regularized least square algorithms with spherical harmonics kernel.The excess error can be estimated by the sum of sample errors and regularization errors.Our study shows that by introducing a suitable spherical harmonics kernel,the regularization parameter can decrease arbitrarily fast with the sample size. 展开更多
关键词 SPHERE regularized regression spherical harmonics kernel rate of convergence
原文传递
Wave propagation of laminated composite plates via GPU-based wavelet finite element method 被引量:5
14
作者 ZUO Hao YANG ZhiBo +2 位作者 SUN Yu XU CaiBin CHEN XueFeng 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2017年第6期832-843,共12页
This paper presents a novel parallel implementation technology for wave-based structural health monitoring (SHM) in laminated composite plates. The wavelet-based B-spline wavelet on he interval (BSWI) element is cons... This paper presents a novel parallel implementation technology for wave-based structural health monitoring (SHM) in laminated composite plates. The wavelet-based B-spline wavelet on he interval (BSWI) element is constructed according to Hamilton’s principle, and the element by element algorithm is parallelly executed on graphics processing unit (GPU) using compute unified device architecture (CUDA) to get the responses in full wave field accurately. By means of the Fourier spectral analysis method,the Mindlin plate theory is selected for wave modeling of laminated composite plates while the Kirchhoff plate theory predicts unreasonably phase and group velocities. Numerical examples involving wave propagation in laminated composite plates without and with crack are performed and discussed in detail. The parallel implementation on GPU is accelerated 146 times comparing with the same wave motion problem executed on central processing unit (CPU). The validity and accuracy of the proposed parallel implementation are also demonstrated by comparing with conventional finite element method (FEM) and the computation time has been reduced from hours to minutes. The damage size and location have been successfully determined according to wave propagation results based on delay-and-sum (DAS). The results show that the proposed parallel implementation of wavelet finite element method (WFEM) is very appropriate and efficient for wave-based SHM in laminated composite plates. 展开更多
关键词 wave propagation laminated composite plates wavelet finite element method parallel implementation structural health monitoring
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部