期刊文献+
共找到10,163篇文章
< 1 2 250 >
每页显示 20 50 100
Using Different Standardized Methods for Species Identification:A Case Study Using Beaks from Three Ommastrephid Species 被引量:4
1
作者 HU Guanyu FANG Zhou +3 位作者 LIU Bilin CHEN Xinjun STAPLES Kevin CHEN Yong 《Journal of Ocean University of China》 SCIE CAS CSCD 2018年第2期355-362,共8页
The cephalopod beak is a vital hard structure with a stable configuration and has been widely used for the identification of cephalopod species. This study was conducted to determine the best standardization method fo... The cephalopod beak is a vital hard structure with a stable configuration and has been widely used for the identification of cephalopod species. This study was conducted to determine the best standardization method for identifying different species by measuring 12 morphological variables of the beaks of Illex argentinus, Ommastrephes bartramii, and Dosidicus gigas that were collected by Chinese jigging vessels. To remove the effects of size, these morphometric variables were standardized using three methods. The average ratios of the upper beak morphological variables and upper crest length of O. bartramii and D. gigas were found to be greater than those of I. argentinus. However, for lower beaks, only the average of LRL(lower rostrum length)/LCL(lower crest length), LRW(lower rostrum width)/LCL, and LLWL(lower lateral wall length)/LCL of O. bartramii and D. gigas were greater than those of I. argentinus. The ratios of beak morphological variables and crest length were found to be all significantly different among the three species(P < 0.001). Among the three standardization methods, the correct classification rate of stepwise discriminant analysis(SDA) was the highest using the ratios of beak morphological variables and crest length. Compared with hood length, the correct classification rate was slightly higher when using beak variables standardized by crest length using an allometric model. The correct classification rate of the lower beak was also found to be greater than that of the upper beak. This study indicates that the ratios of beak morphological variables to crest length could be used for interspecies and intraspecies identification. Meanwhile, the lower beak variables were found to be more effective than upper beak variables in classifying beaks found in the stomachs of predators. 展开更多
关键词 BEAK standardized methods DISCRIMINANT analysis Illex argentinus Ommastrephes bartramii Dosidicus GIGAS
下载PDF
Compilation Principles and Methods of China’s First Mongolian Standard in Meteorological Industry
2
作者 Ying Chun Yu Gang Han Yanli 《Meteorological and Environmental Research》 CAS 2019年第4期118-121,共4页
Mongolian Terms Commonly Used in Meteorological Services that was issued by the China Meteorological Administration is China s first traditional Mongolian standard in meteorological industry. In the process of formula... Mongolian Terms Commonly Used in Meteorological Services that was issued by the China Meteorological Administration is China s first traditional Mongolian standard in meteorological industry. In the process of formulation, the compilation unit fully complied with the principles of scientificity, practicability, universality and versatility, and used literal translation, free translation, and the combination of literal translation and free translation to translate and compile 71 mongolian terms commonly used in meteorological services. The standard fills the blank of standardization construction of basic traditional Mongolian language in the meteorological industry of China. 展开更多
关键词 METEOROLOGY MONGOLIAN language standard COMPILATION PRINCIPLES and methods
下载PDF
LA-ICP-MS Calibrations for Intact Rock Samples with Internal Standard and Modified Constant-Sum Methods
3
作者 Sheng Peng Qinhong Hu 《American Journal of Analytical Chemistry》 2012年第2期168-174,共7页
Laser ablation coupled with inductively coupled plasma-mass spectrometry (LA-ICP-MS) calibration was conducted with multiple spot analyses on eleven intact rock samples using both an internal standard (IS) method and ... Laser ablation coupled with inductively coupled plasma-mass spectrometry (LA-ICP-MS) calibration was conducted with multiple spot analyses on eleven intact rock samples using both an internal standard (IS) method and a modified constant-sum (MCS) method. Methods were then compared for reported bulk elemental composition of the rocks. The MCS method was based on the sum of eight major elements, which is spatially more stable than one single major ele-ment as used in the IS method, and is quite constant among different rock samples. Calibrations were performed with standard reference materials NIST SRM 610, 612, 614, and 616. Little difference was found between using a single standard and a set of standards, because of the good linearity shown by the reference materials. Comparison of the two calibration methods shows that the MCS method produced better and more stable results than the IS method for heterogeneous samples. With the MCS method, approximately 94% to 95% of the total measurements are within the range of ±100% relative deviation, compared with 82% to 86% with the IS method. The IS method resulted insubstantial overestimations for some rock samples (e.g., 648% for Basalt BCR-2 using NIST SRM 610 as the calibration standard), while the largest deviation with the MCS method was 216% for U in Eagle Ford shale #80 sample. For Quartz latite QLO-1, a relative homogeneous sample, the IS method generated slightly better results than the MCS method. Regardless of method, spatially heterogeneous distribution of elements in the intact rock at the scale of the laser spot is considered to be the main reason for the large relative deviations seen in our work compared to published results. 展开更多
关键词 LA-ICP-MS Quantitative Calibration Internal standard method MODIFIED Constant-Sum method
下载PDF
Effectiveness of Participatory Teaching Methods in the Standardized Training of Respiratory Medicine Residents
4
作者 Yanbing Wang Jieru Feng 《Journal of Contemporary Educational Research》 2023年第10期179-184,共6页
Objective:To explore and analyze the application effect of participatory teaching method in the standardized training of respiratory medicine residents.Methods:The study period was from May 2022 to May 2023.20 doctors... Objective:To explore and analyze the application effect of participatory teaching method in the standardized training of respiratory medicine residents.Methods:The study period was from May 2022 to May 2023.20 doctors in the standardized training of respiratory medicine residency in our hospital were taken as research subjects and grouped into the participatory group(n=10)and the routine group(n=10)by using the random number lottery method.The participatory group practised participatory teaching methods,and the routine group practised routine teaching methods.The results of discharge assessment,teaching evaluation,and mini-Clinical Evaluation Exercise(mini-CEX)assessment were compared between the groups.Results:The theoretical assessment,operational assessment,and total scores of the participatory group were significantly higher than those of the routine group,and the difference was statistically significant(P<0.05).The teaching evaluation of independent learning,theoretical mastery,teamwork,clinical thinking,communication,and learning interest of the participatory group was significantly higher than that of the routine group,and the difference was statistically significant(P<0.05).The mini-CEX assessments of history inquiry,organizational effectiveness,professionalism,physical examination,clinical diagnosis,communication skills,and overall clinical competence of the participatory group were significantly better than those of the routine group,and the difference was statistically significant(P<0.05).The teaching satisfaction of the participatory group was significantly higher than that of the routine group,the difference was statistically significant(P<0.05).Conclusion:Participatory teaching methods can improve the overall level of doctors in the respiratory medicine residency standardized training,and the teaching satisfaction is improved. 展开更多
关键词 Participatory teaching method Respiratory medicine RESIDENCY standardized training
下载PDF
Inspiration of Foreign Innovative Drug Pricing Methods and Medical Insurance Payment Standards to China
5
作者 Rao Xiuli Sun Lihua 《Asian Journal of Social Pharmacy》 2023年第4期365-373,共9页
Objective To study the innovative drug pricing methods and medical insurance payment standards in foreign countries and to provide reference for China’s government.Methods The official websites were searched for info... Objective To study the innovative drug pricing methods and medical insurance payment standards in foreign countries and to provide reference for China’s government.Methods The official websites were searched for information and related literature,and literature review was used.Results and Conclusion In foreign countries,the clinical value of innovative drugs and their impact on medical insurance funds were comprehensively evaluated based on factors such as quality-adjusted life years,clinical benefit,and improvement of clinical benefit.Then,the evaluation results were taken as an important basis for whether innovative drugs were admitted to the medical insurance catalog and establishing medical insurance payment standards.By using international experience for reference,innovative drug pricing methods and medical insurance payment standards for China’s national conditions can be improved by establishing a basic database of clinical value and drug economic evaluation of innovative drugs,as well as innovative drug payment models based on decision thresholds. 展开更多
关键词 innovative drug pricing method payment standard medical insurance international experience
下载PDF
Improved EEMD-based standardization method for developing long tree-ring chronologies 被引量:5
6
作者 Xianliang Zhang Junxia Li +1 位作者 Xiaobo Liu Zhenju Chen 《Journal of Forestry Research》 SCIE CAS CSCD 2020年第6期2217-2224,共8页
Long tree-ring chronologies can be developed by overlapping data from living trees with data from fossil trees through cross-dating.However,low-frequency climate signals are lost when standardizing tree-ring series du... Long tree-ring chronologies can be developed by overlapping data from living trees with data from fossil trees through cross-dating.However,low-frequency climate signals are lost when standardizing tree-ring series due to the"segment length curse".To alleviate the segment length curse and thus improve the standardization method for developing long tree-ring chronologies,here we first calculated a mean value for all the tree ring series by overlapping all of the tree ring series.The growth trend of the mean tree ring width(i.e.,cumulated average growth trend of all the series)was determined using ensemble empirical mode decomposition.Then the chronology was developed by dividing the mean value by the growth trend of the mean value.Our improved method alleviated the problem of trend distortion.Long-term signals were better preserved using the improved method than in previous detrending methods.The chronologies developed using the improved method were better correlated with climate than those developed using conservative methods.The improved standardization method alleviates trend distortion and retains more of the low-frequency climate signals. 展开更多
关键词 standardization methods Tree rings Segment length curse DETRENDING
下载PDF
Calculating the Number of Pregnant Women Receiving Standardized Services for PMTCT of HIV in Liangshan Prefecture,Based on the Equivalent Method 被引量:1
7
作者 QU Shui Ling WANG Ai Ling +3 位作者 PAN Xiao Ping WANG Xiao Yan LUO Hui Ming ZHANG Tong 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2020年第10期745-749,共5页
Objective To calculate the number of pregnant women who receive standardized prevention of mother-to-child transmission(PMTCT)services for HIV annually.Methods HIV-positive pregnant women in six counties of Liangshan ... Objective To calculate the number of pregnant women who receive standardized prevention of mother-to-child transmission(PMTCT)services for HIV annually.Methods HIV-positive pregnant women in six counties of Liangshan Prefecture in 2017 were selected as study subjects.The entire process,from when the subjects first received the PMTCT of HIV services to the end,was divided into four stages,which were further divided into 25 phases.The equivalent coefficient was used to indicate the weight of workload in each phase.Seven experts were invited to score the equivalent coefficient;the number of pregnant women who received standardized services to prevent the transmission of HIV was calculated.Results A total of 663 HIV-positive pregnant women were registered in six Liangshan Prefecture counties in 2017.This figure was converted into 7,780 person-months devoted to HIV-positive pregnant women,with 260 person-months(3.34%)spent on the first antenatal care,1,510 person-months(19.41%)during pregnancy,378 person-months(4.86%)on delivery,and 5,632 person-months(72.39%)on post-partum period.The equivalent coefficient calculation showed that 314 HIV-positive pregnant women received standardized PMTCT services.Conclusion The number of pregnant women receiving standardized services for the PMTCT of HIV can be calculated accurately using the equivalent method to identify the gap between the level of PMTCT of HIV intervention services needed and the actual workload. 展开更多
关键词 Equivalent method standardized services PMTCT Pregnant women HIV
下载PDF
Study on the System of Aquatic Environmental Monitoring Methods in China 被引量:1
8
作者 ZHANG Xiao-ling DENG Li SUN Jing 《Meteorological and Environmental Research》 CAS 2012年第3期53-56,共4页
The development of Chinese system of aquatic environmental monitoring methods was summarized. The existing problem of the system of aquatic environmental monitoring methods was analyzed. At last, some suggestions were... The development of Chinese system of aquatic environmental monitoring methods was summarized. The existing problem of the system of aquatic environmental monitoring methods was analyzed. At last, some suggestions were made on setting and implementing the system of aquat- ic environmental monitoring methods in China. 展开更多
关键词 Aquatic quality standards The system of aquatic environmental monitoring methods China
下载PDF
A Mini Review on Testing Methods for Mechanical Properties of Natural Fibre Honeycomb Sandwich Structure and Fractography Analysis 被引量:1
9
作者 Nahiyan Al-Azad Nur Hafidah Binti Dedifitrianto Mohd. Kamal Mohd. Shah 《Journal of Materials Science and Chemical Engineering》 2021年第5期29-38,共10页
This paper is a review of the past research of mechanical testing methods for natural fibre honeycomb sandwich structure as well as failure modes analysis at a microscopic level by using Scanning Electron Microscope (... This paper is a review of the past research of mechanical testing methods for natural fibre honeycomb sandwich structure as well as failure modes analysis at a microscopic level by using Scanning Electron Microscope (SEM). As the world is garnering attention towards renewable resources for environmental purposes, studies of natural fibre have been increasing as well as the application of natural fibre throughout various industries such as aerospace, automobiles, and construction sectors. This paper is started with brief information regarding the honeycomb sandwich structure, introduction to natural fibre, its applications as well as the factors affecting the performances of the structure. Next, the mechanical testing methods are listed out as well as the expected outcomes obtained from the respective testing. The mechanical properties are also identified by conducting lab tests according to the ASTM standard for sandwich and core structures. The microstructure of the deformed samples is then examined under Scanning Electron Microscope (SEM) by using different magnifications to study the failure mechanisms of the samples. The images obtained from the SEM test are analyzed by using fractography which will show the failure modes of the samples. This article is based on past research conducted by professional on the related topic. 展开更多
关键词 Natural Fibre Honeycomb Sandwich Structure Testing methods ASTM standard SEM Test
下载PDF
Smart Society and Artificial Intelligence:Big Data Scheduling and the Global Standard Method Applied to Smart Maintenance 被引量:1
10
作者 Ruben Foresti Stefano Rossi +2 位作者 Matteo Magnani Corrado Guarino Lo Bianco Nicola Delmonte 《Engineering》 SCIE EI 2020年第7期835-846,共12页
The implementation of artificial intelligence(AI)in a smart society,in which the analysis of human habits is mandatory,requires automated data scheduling and analysis using smart applications,a smart infrastructure,sm... The implementation of artificial intelligence(AI)in a smart society,in which the analysis of human habits is mandatory,requires automated data scheduling and analysis using smart applications,a smart infrastructure,smart systems,and a smart network.In this context,which is characterized by a large gap between training and operative processes,a dedicated method is required to manage and extract the massive amount of data and the related information mining.The method presented in this work aims to reduce this gap with near-zero-failure advanced diagnostics(AD)for smart management,which is exploitable in any context of Society 5.0,thus reducing the risk factors at all management levels and ensuring quality and sustainability.We have also developed innovative applications for a humancentered management system to support scheduling in the maintenance of operative processes,for reducing training costs,for improving production yield,and for creating a human–machine cyberspace for smart infrastructure design.The results obtained in 12 international companies demonstrate a possible global standardization of operative processes,leading to the design of a near-zero-failure intelligent system that is able to learn and upgrade itself.Our new method provides guidance for selecting the new generation of intelligent manufacturing and smart systems in order to optimize human–machine interactions,with the related smart maintenance and education. 展开更多
关键词 Smart maintenance Smart society Artificial intelligence Human-centered management system Big data scheduling Global standard method Society 5.0 Industry 4.0
下载PDF
Exploring the Application Effect of Flipped Classroom Combined with Problem-Based Learning Teaching Method in Clinical Skills Teaching of Standardized Training for Resident Doctors of Traditional Chinese Medicine 被引量:1
11
作者 Jingjing Tang 《Journal of Biosciences and Medicines》 CAS 2023年第2期169-176,共8页
Objective: To explore the application effect of flipped classroom combined with problem-based learning teaching method in clinical skills teaching of standardized training for resident doctors of traditional Chinese M... Objective: To explore the application effect of flipped classroom combined with problem-based learning teaching method in clinical skills teaching of standardized training for resident doctors of traditional Chinese Medicine. Methods: The study used the experimental control method. The study lasted from September to November 2022. The subjects of this study were 49 students of standardized training for resident doctors of traditional Chinese Medicine from grades 2020, 2021 and 2022 of Dazhou integrated TCM & Western Medicine Hospital. They were randomly divided into experiment group (25) and control group (24). The experiment group adopted flipped classroom combined with problem-based learning teaching method, and the control group adopted traditional teaching method. The teaching content was 4 basic clinical skill projects, including four diagnoses of traditional Chinese Medicine, cardiopulmonary resuscitation, dressing change procedure, acupuncture and massage. The evaluation method was carried out by comparing the students’ performance and a self-designed questionnaire was used to investigate the students’ evaluation of the teaching method. Results: The test scores of total scores in the experimental group (90.12 ± 5.89) were all higher than those in the control group (81.47 ± 7.96) (t = 4.53, P P Conclusions: The teaching process of the flipped classroom combined with problem-based learning teaching method is conducive to improving the efficiency of classroom teaching, cultivating students’ self-learning ability, and enhancing students’ willingness to learn. 展开更多
关键词 standardized Training for Resident Doctors of Traditional Chinese Medicine Clinical Skills Teaching Flipped Classroom Problem-Based Learning Teaching method
下载PDF
Analytical and Traveling Wave Solutions to the Fifth Order Standard Sawada-Kotera Equation via the Generalized exp(-Φ(ξ))-Expansion Method 被引量:1
12
作者 M. Y. Ali M. G. Hafez +1 位作者 M. K. H. Chowdury M. T. Akter 《Journal of Applied Mathematics and Physics》 2016年第2期262-271,共10页
In this article, we propose a generalized exp(-Φ(ξ))-expansion method and successfully implement it to find exact traveling wave solutions to the fifth order standard Sawada-Kotera (SK) equation. The exact traveling... In this article, we propose a generalized exp(-Φ(ξ))-expansion method and successfully implement it to find exact traveling wave solutions to the fifth order standard Sawada-Kotera (SK) equation. The exact traveling wave solutions are established in the form of trigonometric, hyperbolic, exponential and rational functions with some free parameters. It is shown that this method is standard, effective and easily applicable mathematical tool for solving nonlinear partial differential equations arises in the field of mathematical physics and engineering. 展开更多
关键词 Generalized exp(-Φ(ξ))-Expansion method Fifth Order standard Sawada-Kotera Equation SOLITONS Periodic Wave Solutions
下载PDF
Design Method of Equipment Optimization Development Based on Standardization Theory 被引量:2
13
作者 Lv-bo MAI 《Defence Technology(防务技术)》 SCIE EI CAS 2013年第3期140-145,共6页
The matters of equipment optimization development are usually discrete,fuzzy and non-quantitative.It is difficult directly to optimize the equipment development with a mathematical model.A set of methods for designing... The matters of equipment optimization development are usually discrete,fuzzy and non-quantitative.It is difficult directly to optimize the equipment development with a mathematical model.A set of methods for designing the equipment optimization development with six dimensions and eight main elements is established based on the theory and method of standardization.The top-tier design space of systematic development of equipment is built up by the relations of basic models,series and model spectrums.The relations of time and space for equipment optimization development are established.The design processes of a six dimension systematic space are expounded.The connotation of each plan in the main system space is analyzed.A design method for an entire equipment is established with standardization theory.The coordinating design methods of equipment technical system and the optimization design methods of equipment integration are discussed.The design methods for universalization and serialization of components and parts are established.The design methods of equipment optimization development highlight the relations of the basic model of platform,the serialization of platform basic models,the modularization of equipment functions,the model spectrum of variant equipment,and the universalization and serialization of components and parts. 展开更多
关键词 优化设计方法 优化开发 化设备 标准化 优化发展 数学模型 设计空间 设备系统
下载PDF
The Research on Methodology for Material Code Standardization in the Implementation of MRP-Ⅱ
14
作者 孙虞 《Journal of Southeast University(English Edition)》 EI CAS 1996年第2期13-18,共6页
This paper analyses the current common problems of material code standardization in the implementation of MRP Ⅱ, and puts forward the basic ideas and methods for solving the problems, which has some reference value ... This paper analyses the current common problems of material code standardization in the implementation of MRP Ⅱ, and puts forward the basic ideas and methods for solving the problems, which has some reference value for the popularization of application o 展开更多
关键词 CODING standard methods
下载PDF
Multilevel grey evaluation on the comprehensive contribution of standards to Shanghai automobile industry
15
作者 陶城 宋静 《Journal of Shanghai University(English Edition)》 CAS 2010年第4期301-305,共5页
Standard has played an important role in modern enterprises and society through the encouragement of technology innovation and distribution. Based on the survey of 30 typical enterprises in the field of automobile in ... Standard has played an important role in modern enterprises and society through the encouragement of technology innovation and distribution. Based on the survey of 30 typical enterprises in the field of automobile in Shanghai, this paper makes quantitative analysis on comprehensive contribution of standard to automobile industry and accomplishes the demonstration of standard comprehensive evaluation index system. The analysis shows that standardization makes obvious contribution to Shanghai automobile industry. 展开更多
关键词 standardIZATION evaluation index comprehensive contribution of standards analytic hierarchy process (AHP)method multilevel fussy comprehensive evaluation
下载PDF
MULTI-PARAMETER ACCELERATED MODIFIED NEWTON-RAPHSON METHODS FOR RIGIDPLASTIC FE ANALYSIS
16
作者 Shi Gang Liu Xiaolin 《Acta Mechanica Solida Sinica》 SCIE EI 2002年第4期323-331,共9页
Applications of certain multi-parameter acceleration techniques used with themodified New-ton-Raphson (mN-R) methods to solve the nonlinear equations arising from rigid-plasticfinite element analysis are investigated.... Applications of certain multi-parameter acceleration techniques used with themodified New-ton-Raphson (mN-R) methods to solve the nonlinear equations arising from rigid-plasticfinite element analysis are investigated. New modified multi-parameter techniques, developed fromCrisfield's multi-parameter methods, are utilized to solve these nonlinear equations. The numericalperformance of these techniques is compared with the standard Newton-Raphson method (sN-R),Crisfield's single parameter method (C1), Crisfield's two parameter method (C2) and Crisfield'sthree parameter method (C3). The new techniques do not involve additional residual force calculationand require little extra computational effort. In addition, they are more robust and efficient thanother existing acceleration techniques. 展开更多
关键词 rigid-plastic FEM standard newton-raphson method modified newton-raphsonmethod crisfield's multi-parameter accelerated techniques modified multi-parameter acceleratedtechniques
下载PDF
Synthesis of an IS and Steviol Glycoside Analysis by a Validated Internal Standard Method
17
作者 Jan M. C. Geuns Tom Struyf +2 位作者 Stijn Ceunen Gert Steurs Wim De Borggraeve 《American Journal of Analytical Chemistry》 2018年第11期547-559,共13页
The internal standard (IS) method is the best method for the analysis of samples, as it is independent of errors in injection volume, changes in sample volumes, and changes in sensitivity of the detector, etc. Use of ... The internal standard (IS) method is the best method for the analysis of samples, as it is independent of errors in injection volume, changes in sample volumes, and changes in sensitivity of the detector, etc. Use of an internal standard allows for the correction of losses due to sample clean-up of complex samples. An ideal IS is a compound that has properties very similar to, and that behaves as the compounds to be analysed. Ideally, only in the last step of analysis (HPLC), the IS should be well separated from the compounds of the mixture to be analysed. After testing several existing compounds with negative results, we decided to synthesise the 19-O-β-D-galactopyranosyl-13-O-β-D-glucopyranosyl-steviol as IS. This is the 19-galactosyl ester of steviolmonoside (13-O-β-D-glucopyranosyl-steviol). The IS was made according to published methods. Steviolmonoside (SM) was made from purified commercial rubusoside (Rub) by refluxing it in 10% KOH for 2 h. SM was precipitated and crystallized from MeOH. The hydroxyls of the glucose unit of SM were protected by acetylation. The acetylated SM was crystallized from acetone and dissolved in 1,2-dichloroethane. Then Ag2CO3 on Celite and tetra-acetylated galactopyranosyl bromide were added and the mixture was refluxed for 2 h. After cooling, BaO in MeOH was added to remove the acetyl groups. The 1,2-dichloroethane fraction was then extracted three times with equal volumes of water and the water fraction containing the IS was further purified on a C18 flash chromatography column. Traces of unreacted SM were removed by preparative HPLC on an Alltima C18 column (250 mm × 22 mm, particle size 10 μm) with AcCN:water (35:65, 20 ml/min). Detection was at 210 nm (KNAUER, “Smartline” UV detector 2500). The collected IS fraction from the HPLC was completely dried. Mixtures of steviol glycosides (SVglys) containing IS could be purified over SPE cartridges without change of the SVgly over IS ratio. The calibration curves for rebaudioside A (RebA) and stevioside (ST) were linear between 0.012 and 0.95 and between 0.013 and 1.13 mM for RebA and ST, respectively. The accuracy was checked by the standard addition method. It was concluded that the IS method gives an excellent precision and accuracy. 展开更多
关键词 STEVIOL GLYCOSIDES INTERNAL standard method VALIDATION Quantification PURIFICATION
下载PDF
The Measurement and Uncertainty Analysis of Antenna Factor of Microwave Antennas Based on Standard Site Method
18
作者 Chaochan Chen Hong Shi +1 位作者 Yi Miao Yu Sang 《International Journal of Communications, Network and System Sciences》 2017年第5期138-145,共8页
A method of Standard Site Method (SSM) in the American National Standards Institute’s ANSI C63.5 is described in the frequency ranges from 30 MHz to 1000 MHz. And a measurement system is set up for determining antenn... A method of Standard Site Method (SSM) in the American National Standards Institute’s ANSI C63.5 is described in the frequency ranges from 30 MHz to 1000 MHz. And a measurement system is set up for determining antenna factors (AF) of antennas on an Open Area Test Sites (OATS). AF of antennas including log-periodic antenna and biconical antenna is measured with SSM method by Shanghai Institute of Measurement and Testing Technology (SIMT), which shows good agreement to data measured by National Institute of Metrology (NIM). In the end, it analyzes the measurement uncertainty of SIMT in the 30 MHz to 1000 MHz frequency band and does comparison to that of NIM. 展开更多
关键词 ANTENNA FACTORS standard SITE method (SSM) MEASUREMENT UNCERTAINTY
下载PDF
Methods for Setting up a Three-Dimensional Industrial Surveying System of “Building Blocks Type”
19
作者 FENGWenhao 《Geo-Spatial Information Science》 2004年第3期157-161,共5页
This paper is to advance some relevant techniques to set up a three-dimensional industrial surveying system of “building blocks type”, making use of the electronic theodolite, standard ruler and portable computer.
关键词 three-dimensional industrial surveying system initial direction innertarget collimator method standard ruler accuracy
下载PDF
Current dependence coefficient determination for different DC standard resistors measurements based on Ⅴ-Ⅰ method
20
作者 Rasha S M Ali M Helmy A Raouf 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2016年第4期332-335,共4页
Current dependence and stability of the measured resistance value are very important for the accurate measurement of DC standard resistor. In this paper, the volt-ampere (V-I) measurement method has been applied ... Current dependence and stability of the measured resistance value are very important for the accurate measurement of DC standard resistor. In this paper, the volt-ampere (V-I) measurement method has been applied to study the current depend-ence of four different types of standard resistors. Diverse values are obtained through the investigation of their stability at dif-ferent currents. Therefore, the current dependence coefficient (CDC) can be determined for each one of the studied resistors. Research shows CDC depends on the applied current value, the measurement time and the resistor type, as clearly demonstra-ted in this research. 展开更多
关键词 current dependence coefficient standard resistors volt-ampere method resistor stability
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部