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Measurement and Evaluation of the Business Environment in Large and Medium-Sized Cities in China
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作者 Yi Zhang 《Proceedings of Business and Economic Studies》 2024年第3期75-79,共5页
The comprehensive development level of the business environment reflects the quality of a region’s economic development,and a good business environment will give a city a strong vitality.This paper uses the entropy m... The comprehensive development level of the business environment reflects the quality of a region’s economic development,and a good business environment will give a city a strong vitality.This paper uses the entropy method to measure and evaluate the business environment of 106 large and medium-sized cities in China from 2017 to 2021.The results show that:From the spatial point of view,the business environment index of China’s cities shows a gradually decreasing pattern from east to west and from south to north.The balance of the business environment of large and medium-sized cities in China is divided into four levels according to the standard deviation of the ranking of each subindex.The greater the standard deviation,the more unbalanced the overall development of the business environment in the region.Finally,this paper put forward countermeasures and suggestions to further optimize the business environment. 展开更多
关键词 Business environment evaluation system Entropy evaluation method
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Online Capacitor Voltage Transformer Measurement Error State Evaluation Method Based on In-Phase Relationship and Abnormal Point Detection
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作者 Yongqi Liu Wei Shi +2 位作者 Jiusong Hu Yantao Zhao Pang Wang 《Smart Grid and Renewable Energy》 2024年第1期34-48,共15页
The assessment of the measurement error status of online Capacitor Voltage Transformers (CVT) within the power grid is of profound significance to the equitable trade of electric energy and the secure operation of the... The assessment of the measurement error status of online Capacitor Voltage Transformers (CVT) within the power grid is of profound significance to the equitable trade of electric energy and the secure operation of the power grid. This paper advances an online CVT error state evaluation method, anchored in the in-phase relationship and outlier detection. Initially, this method leverages the in-phase relationship to obviate the influence of primary side fluctuations in the grid on assessment accuracy. Subsequently, Principal Component Analysis (PCA) is employed to meticulously disentangle the error change information inherent in the CVT from the measured values and to compute statistics that delineate the error state. Finally, the Local Outlier Factor (LOF) is deployed to discern outliers in the statistics, with thresholds serving to appraise the CVT error state. Experimental results incontrovertibly demonstrate the efficacy of this method, showcasing its prowess in effecting online tracking of CVT error changes and conducting error state assessments. The discernible enhancements in reliability, accuracy, and sensitivity are manifest, with the assessment accuracy reaching an exemplary 0.01%. 展开更多
关键词 Capacitor Voltage Transformer measurement Error Online Monitoring Principal Component Analysis Local Outlier Factor
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Evaluation of Dosimetric Impact of Uncertainty of Measurement in Estimating External Radiotherapy Dose
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作者 Collins Omondi Margaret Chege Samson Omondi 《Open Journal of Applied Sciences》 2024年第8期1985-1995,共11页
Cancer is a major societal public health and economic problem, responsible for one in every six deaths. Radiotherapy is the main technique of treatment for more than half of cancer patients. To achieve a successful ou... Cancer is a major societal public health and economic problem, responsible for one in every six deaths. Radiotherapy is the main technique of treatment for more than half of cancer patients. To achieve a successful outcome, the radiation dose must be delivered accurately and precisely to the tumor, within ± 5% accuracy. Smaller uncertainties are required for better treatment outcome. The objective of the study is to investigate the uncertainty of measurement of external radiotherapy beam using a standard ionization chamber under reference conditions. Clinical farmers type ionization chamber measurement was compared against the National Reference standard, by exposing it in a beam 60Co gamma source. The measurement set up was carried out according to IAEA TRS 498 protocol and uncertainty of measurement evaluated according to GUM TEDDOC-1585. Evaluation and analysis were done for the identified subjects of uncertainty contributors. The expanded uncertainty associated with 56 mGy/nC ND,W was found to be 0.9% corresponding to a confidence level of approximately 95% with a coverage factor of k = 2. The study established the impact of dosimetry uncertainty of measurement in estimating external radiotherapy dose. The investigation established that the largest contributor of uncertainty is the stability of the ionization chamber at 36%, followed by temperature at 22% and positioning of the chamber in the beam at 8%. The effect of pressure, electrometer, resolution, and reproducibility were found to be minimal to the overall uncertainty. The study indicate that there is no flawless measurement, as there are many prospective sources of variation. Measurement results have component of unreliability and should be regarded as best estimates of the true value. . 展开更多
关键词 Absorbed Dose to Water RADIOTHERAPY Uncertainty of measurement Secondary Standards Dosimetry Laboratory Ionizing Chamber
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Laser Measurement and Intensity Evaluation of Intake Swirl in Engine Using a Water Analog 被引量:4
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作者 孙柏刚 李向荣 杜巍 《Journal of Beijing Institute of Technology》 EI CAS 2000年第4期391-396,共6页
The intake swirl in the cylinder was induced by a swirler which was fixed in one of two intake ports. In order to understand the characteristics of the intake swirl, a transparent water analog was designed which simul... The intake swirl in the cylinder was induced by a swirler which was fixed in one of two intake ports. In order to understand the characteristics of the intake swirl, a transparent water analog was designed which simulated 150 type single cylinder engine. At the same time, the particle image velocimetry was used to measure the flow fields induced by various swirlers in the analog. After measurement, a new method was presented to evaluate the intensity of the intake swirl. Then, when the measured sections, the lifts of valve and the swirlers were different, the calculated results of the flow field were compared. 展开更多
关键词 diesel engine intake swirl water analog particle image velocimetry measurement
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Correlation between the rock mass properties and maximum horizontal stress:A case study of overcoring stress measurements
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作者 Peng Li Meifeng Cai +2 位作者 Shengjun Miao Yuan Li Yu Wang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS 2025年第1期39-48,共10页
Understanding the mechanical properties of the lithologies is crucial to accurately determine the horizontal stress magnitude.To investigate the correlation between the rock mass properties and maximum horizontal stre... Understanding the mechanical properties of the lithologies is crucial to accurately determine the horizontal stress magnitude.To investigate the correlation between the rock mass properties and maximum horizontal stress,the three-dimensional(3D)stress tensors at 89 measuring points determined using an improved overcoring technique in nine mines in China were adopted,a newly defined characteristic parameter C_(ERP)was proposed as an indicator for evaluating the structural properties of rock masses,and a fuzzy relation matrix was established using the information distribution method.The results indicate that both the vertical stress and horizontal stress exhibit a good linear growth relationship with depth.There is no remarkable correlation between the elastic modulus,Poisson's ratio and depth,and the distribution of data points is scattered and messy.Moreover,there is no obvious relationship between the rock quality designation(RQD)and depth.The maximum horizontal stress σ_(H) is a function of rock properties,showing a certain linear relationship with the C_(ERP)at the same depth.In addition,the overall change trend of σ_(H) determined by the established fuzzy identification method is to increase with the increase of C_(ERP).The fuzzy identification method also demonstrates a relatively detailed local relationship betweenσ_H and C_(ERP),and the predicted curve rises in a fluctuating way,which is in accord well with the measured stress data. 展开更多
关键词 overcoring stress measurements elastic modulus Poisson's ratio rock quality designation maximum horizontal stress fuzzy identification
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Evaluation of the effectiveness of preventive nursing measures for pressure injuries in patients in the neurology intensive care unit
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作者 Rong Zhang Peng-Xin Ma Juan-Juan Zhang 《World Journal of Clinical Cases》 SCIE 2024年第19期3807-3814,共8页
BACKGROUND Patients in neurology intensive care units(ICU)are prone to pressure injuries(PU)due to factors such as severe illness,long-term bed rest,and physiological dysfunction.PU not only causes pain and complicati... BACKGROUND Patients in neurology intensive care units(ICU)are prone to pressure injuries(PU)due to factors such as severe illness,long-term bed rest,and physiological dysfunction.PU not only causes pain and complications to patients,but also increases medical burden,prolongs hospitalization time,and affects the recovery process.AIM To evaluate and optimize the effectiveness of pressure injury prevention nursing measures in neurology ICU patients.METHODS A retrospective study was conducted,and 60 patients who were admitted to the ICU of the Department of Neurology were selected and divided into an observation group and a control group according to the order of admission,with 30 people in each group.The observation group implemented pressure injury prevention and nursing measures,while the control group adopted routine care.RESULTS Comparison between observation and control groups following pressure injury prevention nursing intervention revealed significantly lower incidence rates in the observation group compared to the control group at 48 h(8.3%vs 26.7%),7 d(16.7%vs 43.3%),and 14 d(20.0%vs 50.0%).This suggests a substantial reduction in pressure injury incidence in the observation group,with the gap widening over time.Additionally,patients in the observation group exhibited quicker recovery,with a shorter average time to get out of bed(48 h vs 72 h)and a shorter average length of stay(12 d vs 15 d)compared to the control group.Furthermore,post-intervention,patients in the observation group reported significantly improved quality of life scores,including higher scores in body satisfaction,feeling and function,and comfort(both psychological and physiological),indicating enhanced overall well-being and comfort following the implementation of pressure injury prevention nursing measures.CONCLUSION Implementing pressure injury preventive care measures for neurology ICU patients will have better results. 展开更多
关键词 Neurology intensive care units Pressure injury Preventive care Effect evaluation Optimization research Prognostic effect
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Evaluation of the International Vehicle Emission (IVE) model with on-road remote sensing measurements 被引量:24
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作者 GUO Hui ZHANG Qing-yu +1 位作者 SHI Yao WANG Da-hui 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第7期818-826,共9页
Intemational Vehicle Emissions (IVE) model funded by U.S. Environmental Protection Agency (USEPA) is designed to estimate emissions from motor vehicles in developing countries. In this study, the IVE model was eva... Intemational Vehicle Emissions (IVE) model funded by U.S. Environmental Protection Agency (USEPA) is designed to estimate emissions from motor vehicles in developing countries. In this study, the IVE model was evaluated by utilizing a dataset available from the remote sensing measurements on a large number of vehicles at five different sites in Hangzhou, China, in 2004 and 2005. Average fuel-based emission factors derived from the remote sensing measurements were compared with corresponding emission factors derived from IVE calculations for urban, hot stabilized condition. The results show a good agreement between the two methods for gasoline passenger cars' HC emission for all 1VE subsectors and technology classes. In the case of CO emissions, the modeled results were reasonably good, although systematically underestimate the emissions by almost 12%-50% for different technology classes. However, the model totally overestimated NOx emissions. The IVE NOx emission factors were 1.5-3.5 times of the remote sensing measured ones. The IVE model was also evaluated for light duty gasoline truck, heavy duty gasoline vehicles and motor cycles. A notable result was observed that the decrease in emissions from technology class State II to State I were overestimated by the IVE model compared to remote sensing measurements for all the three pollutants. Finally, in order to improve emission estimation, the adjusted base emission factors from local studies are strongly recommended to be used in the IVE model. 展开更多
关键词 remote sensing IVE model fuel-based emission factor evaluation
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First Evaluation and Frequency Measurement of the Strontium Optical Lattice Clock at NIM 被引量:14
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作者 林弋戈 王强 +7 位作者 李烨 孟飞 林百科 臧二军 孙震 房芳 李天初 方占军 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第9期17-20,共4页
An optical lattice clock based on 87Sr is built at National Institute of Metrology (NIM) of China. The systematic frequency shifts of the clock are evaluated with a total uncertainty of 2.3×10-16. To measure it... An optical lattice clock based on 87Sr is built at National Institute of Metrology (NIM) of China. The systematic frequency shifts of the clock are evaluated with a total uncertainty of 2.3×10-16. To measure its absolute frequency with respect to NIM's cesium fountain clock NIM5, the frequency of a flywheel H-maser of NIM5 is transferred to the Sr laboratory through a 50-kin-long fiber. reference frequency of this H-maser, is used for the optical this Sr clock is measured to be 429228004229873.7(1.4)Hz. A fiber optical frequency comb, phase-locked to the frequency measurement. The absolute frequency of 展开更多
关键词 AOM First evaluation and Frequency measurement of the Strontium Optical Lattice Clock at NIM
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New Measurement Method for Spline Shaft Rolling Performance Evaluation using Laser Displacement Sensor 被引量:4
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作者 Hong-Wei Li Zhi-Qiang Liang +3 位作者 Jia-Jie Pei Li Jiao Li-Jing Xie Xi-Bin Wang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2018年第4期124-132,共9页
In order to control the quality of spline shaft in rolling process, an efficient measurement method for rolling performance evaluation is essential. Here, a newly developed on-machine non-contact measurement prototype... In order to control the quality of spline shaft in rolling process, an efficient measurement method for rolling performance evaluation is essential. Here, a newly developed on-machine non-contact measurement prototype based on laser displacement sensor and rotary encoder is proposed. The prototype is intended for the automated evaluation of the spline shaft rolling performance by measuring the dimensional change of tooth root, which is correlated with the surface residual stress and micro-hardness. Laser displacement sensor and rotary encoder are used to record the polar radius and polar angle of each point on measuring section. Data are displayed in a polar coordinate system and fitted in a gear. Through multipoint curvature method, the roots of spline shaft are recognized automatically. Then, the dimensional change can be calculated by fitting the radius of the tooth root circle before and after rolling. Systematic error covering offset error is also analyzed and calibrated. At last, measurement test results show that the system has advantages of simple structure, high measurement precision(radius error < 0.6 μm), high measurement efficiency(measuring time < 2 s) and automatic control ability, providing a new opportunity for the efficient evaluation of various spline shafts in high-precision mechanical processing. 展开更多
关键词 Laser measurement Spline shaft Rolling performance Dimensional change
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Measurement Uncertainty Evaluation of Conicity Error Inspected on CMM 被引量:11
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作者 WANG Dongxia SONG Aiguo +2 位作者 WEN Xiulan XU Youxiong QIAO Guifang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第1期212-218,共7页
The cone is widely used in mechanical design for rotation, centering and fixing. Whether the conicity error can be measured and evaluated accurately will directly influence its assembly accuracy and working performanc... The cone is widely used in mechanical design for rotation, centering and fixing. Whether the conicity error can be measured and evaluated accurately will directly influence its assembly accuracy and working performance. According to the new generation geometrical product specification(GPS), the error and its measurement uncertainty should be evaluated together. The mathematical model of the minimum zone conicity error is established and an improved immune evolutionary algorithm(IlEA) is proposed to search for the conicity error. In the IIEA, initial antibodies are firstly generated by using quasi-random sequences and two kinds of affinities are calculated. Then, each antibody clone is generated and they are self-adaptively mutated so as to maintain diversity. Similar antibody is suppressed and new random antibody is generated. Because the mathematical model of conicity error is strongly nonlinear and the input quantities are not independent, it is difficult to use Guide to the expression of uncertainty in the measurement(GUM) method to evaluate measurement uncertainty. Adaptive Monte Carlo method(AMCM) is proposed to estimate measurement uncertainty in which the number of Monte Carlo trials is selected adaptively and the quality of the numerical results is directly controlled. The cone parts was machined on lathe CK6140 and measured on Miracle NC 454 Coordinate Measuring Machine(CMM). The experiment results confirm that the proposed method not only can search for the approximate solution of the minimum zone conicity error(MZCE) rapidly and precisely, but also can evaluate measurement uncertainty and give control variables with an expected numerical tolerance. The conicity errors computed by the proposed method are 20%-40% less than those computed by NC454 CMM software and the evaluation accuracy improves significantly. 展开更多
关键词 minimum zone conicity error improved immune evolutionary algorithm measurement uncertainty adaptive Monte Carlo method
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Experiments on acoustic measurement of fractured rocks and application of acoustic logging data to evaluation of fractures 被引量:4
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作者 Bao-Zhi Pan Ming-Xin Yuan +3 位作者 Chun-Hui Fang Wen-Bin Liu Yu-Hang Guo Li-Hua Zhang 《Petroleum Science》 SCIE CAS CSCD 2017年第3期520-528,共9页
Fractures in oil and gas reservoirs have been the topic of many studies and have attracted reservoir research all over the world. Because of the complexities of the fractures, it is difficult to use fractured reservoi... Fractures in oil and gas reservoirs have been the topic of many studies and have attracted reservoir research all over the world. Because of the complexities of the fractures, it is difficult to use fractured reservoir core samples to investigate true underground conditions. Due to the diversity of the fracture parameters, the simulation and evaluation of fractured rock in the laboratory setting is also difficult. Previous researchers have typically used a single material, such as resin, to simulate fractures. There has been a great deal of simplifying of the materials and conditions, which has led to disappointing results in application. In the present study, sandstone core samples were selected and sectioned to simulate fractures, and the changes of the compressional and shear waves were measured with the gradual increasing of the fracture width. The effects of the simulated fracture width on the acoustic wave velocity and amplitude were analyzed. Two variables were defined: H represents the amplitude attenuation ratio of the compressional and shear wave, and x represents the transit time difference value of the shear wave and compressional wave divided by the transit time of the compressional wave. The effect of fracture width on these two physical quantities was then analyzed. Finally, the methods of quantitative evaluation for fracture width with H and x were obtained. The experimental results showed that the rock fractures linearly reduced the velocity of the shear and compressional waves. The effect of twin fractures on thecompressional velocity was almost equal to that of a single fracture which had the same fracture width as the sum of the twin fractures. At the same time, the existence of fractures led to acoustic wave amplitude attenuations, and the compressional wave attenuation was two times greater than that of the shear wave. In this paper, a method was proposed to calculate the fracture width with x and H, then this was applied to the array acoustic imaging logging data.The application examples showed that the calculated fracture width could be compared with fractures on the electric imaging logs. These rules were applied in the well logs to effectively evaluate the fractures, under the case of no image logs, which had significance to prospecting and development of oil and gas in fractured reservoirs. 展开更多
关键词 Fractured rockAcoustic wave amplitude Fracture width Acoustic wave velocity Experimental measurement
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Performance evaluation of two types of heated cables for distributedtemperature sensing-based measurement of soil moisture content 被引量:10
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作者 Dingfeng Cao Bin Shi +3 位作者 Honghu Zhu Kun Zhu Guangqing Wei Kai Gu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2016年第2期212-217,共6页
Distributed temperature sensing(DTS)using heated cables has been recently developed for distributed monitoring of in-situ soil moisture content.In this method,the thermal and electrical properties of heated cables hav... Distributed temperature sensing(DTS)using heated cables has been recently developed for distributed monitoring of in-situ soil moisture content.In this method,the thermal and electrical properties of heated cables have a significant influence on the measurement accuracy of soil moisture content.In this paper,the performances of two heated cables,i.e.the carbon-fiber heated cable(CFHC)and the metalnet heated cable(MNHC),are studied in the laboratory.Their structures,uniformity in the axial direction,measurement accuracy and suitability are evaluated.The test results indicate that the MNHC has a better uniformity in the axial direction than CFHC.Both CFHC and MNHC have high measurement accuracy.The CFHC is more suitable for short-distance measurement(500 m),while the MNHC can be used for longdistance measurement(>500 m). 展开更多
关键词 Soil moisture content Carbon-fiber heated cable(CFHC) Metal-net heated cable(MNHC) Distributed measurement Optical fiber
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Evaluation of wind vectors observed by HY-2A scatterometer using ocean buoy observations,ASCAT measurements,and numerical model data 被引量:5
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作者 李大伟 申辉 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2015年第5期1191-1200,共10页
The first Chinese microwave ocean environment satellite HY-2A was launched successfully in August, 201 I. This study presents a quality assessment of HY-2A scatterometer (HYSCAT) data based on comparison with ocean ... The first Chinese microwave ocean environment satellite HY-2A was launched successfully in August, 201 I. This study presents a quality assessment of HY-2A scatterometer (HYSCAT) data based on comparison with ocean buoy data, the Advanced Scatterometer (ASCAT) data, and numerical model data from the National Centers for Environmental Prediction (NCEP). The in-situ observations include those from buoy arrays operated by the National Data Buoy Center (NDBC) and Tropical Atmosphere Ocean (TAO) project. Only buoys located offshore and in deep water were analyzed. The temporal and spatial collocation windows between HYSCAT data and buoy observations were 30 min and 25 km, respectively. The comparisons showed that the wind speeds and directions observed by HYSCAT agree well with the buoy data. The root-mean-squared errors (RMSEs) of wind speed and direction for the HYSCAT standard wind products are 1.90 m/s and 22.80°, respectively. For the HYSCAT-ASCAT comparison, the temporal and spatial differences were limited to 1 h and 25 km, respectively. This comparison yielded RMSEs of 1.68 m/s for wind speed and 19.1° for wind direction. We also compared HYSCAT winds with reanalysis data from NCEP. The results show that the RMSEs of wind speed and direction are 2.6 m/s and 26°, respectively. The global distribution of wind speed residuals (HYSCAT-NCEP) is also presented here for evaluation of the HYSCAT-retrieved wind field globally. Considering the large temporal and spatial differences of the collocated data, it is concluded that the HYSCAT-retrieved wind speed and direction met the mission requirements, which were 2 rn/s and 20° for wind speeds in the range 2-24 m/s. These encouraging assessment results show that the wind data obtained from HYSCAT will be useful for the scientific community. 展开更多
关键词 HY-2A SCATTEROMETER wind fields evaluation
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Real-time reliability evaluation based on damaged measurement degradation data 被引量:16
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作者 王小林 蒋平 +1 位作者 郭波 程志君 《Journal of Central South University》 SCIE EI CAS 2012年第11期3162-3169,共8页
A method was proposed to evaluate the real-time reliability for a single product based on damaged measurement degradation data.Most researches on degradation analysis often assumed that the measurement process did not... A method was proposed to evaluate the real-time reliability for a single product based on damaged measurement degradation data.Most researches on degradation analysis often assumed that the measurement process did not have any impact on the product's performance.However,in some cases,the measurement process may exert extra stress on products being measured.To obtain trustful results in such a situation,a new degradation model was derived.Then,by fusing the prior information of product and its own on-line degradation data,the real-time reliability was evaluated on the basis of Bayesian formula.To make the proposed method more practical,a procedure based on expectation maximization (EM) algorithm was presented to estimate the unknown parameters.Finally,the performance of the proposed method was illustrated by a simulation study.The results show that ignoring the influence of the damaged measurement process can lead to biased evaluation results,if the damaged measurement process is involved. 展开更多
关键词 degradation analysis damaged measurement real-time reliability expectation maximization algorithm
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Safety evaluation for railway vehicles using an improved indirect measurement method of wheel–rail forces 被引量:8
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作者 Jing Zeng Lai Wei Pingbo Wu 《Journal of Modern Transportation》 2016年第2期114-123,共10页
The wheel-rail force measurement is of great importance to the condition monitoring and safety evaluation of railway vehicles. In this paper, an improved indirect method for wheel-rail force measurement is proposed to... The wheel-rail force measurement is of great importance to the condition monitoring and safety evaluation of railway vehicles. In this paper, an improved indirect method for wheel-rail force measurement is proposed to evaluate the running safety of railway vehicles. In this method, the equilibrium equations of a suspended wheelset are derived and the wheel-rail forces are then be obtained from measured suspension and inertia forces. This indirect method avoids structural modifications to the wheelset and is applicable to the long-term operation of railway vehicles. As the wheel-rail lateral forces at two sides of the wheelset are difficult to separate, a new derailment criterion by combined use of wheelset derailment coefficient and wheel unloading ratio is proposed. To illustrate its effectiveness, the indirect method is applied to safety evaluation of rail- way vehicles in different scenarios, such as the cross wind safety of a high-speed train and the safety of a metro vehicle with hunting motions. Then, the feasibility of using this method to identify wheel-rail forces for low-floor light rail vehicles with resilient wheels is discussed. The values identified by this method is compared with that by Simpack simulation for the same low-floor vehicle, which shows a good coincidence between them in the time domain of the wheelset lateral force and the wheel-rail vertical force. In addition, use of the method to determine the high-frequency wheel-rail interaction forces reveals that it is possible to identify the high-frequency wheel-rail forces through the accelerations on the axle box. 展开更多
关键词 Wheel-rail force Safety evaluation - Indirect method Union safety domain Wheelset derailment coefficient Hunting motions Cross wind Low-floor vehicle
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Multilevel Tests and Measurement Evaluation Methods for the Application of Composite Materials in Spacecraft Structures 被引量:1
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作者 WANG Yuhang GUO Liangshuai +2 位作者 ZHOU Peng ZHANG Tao WANG Fuhui 《上海航天(中英文)》 CSCD 2022年第1期111-121,共11页
With the implementation of new-generation launch vehicles,space stations,lunar and deep space exploration,etc.,the development of spacecraft structures will face new challenges. In order to reduce the spacecraft weigh... With the implementation of new-generation launch vehicles,space stations,lunar and deep space exploration,etc.,the development of spacecraft structures will face new challenges. In order to reduce the spacecraft weight and increase the payload,composite material structures will be widely used. It is difficult to evaluate the strength and life of composite materials due to their complex mechanism and various phenomena in damage and failure.Meanwhile,the structures of composite materials used in spacecrafts will bear complex loads,including the coupling loads of tension,pressure,bending,shear,and torsion. Static loads,thermal loads,and vibration loads may occur at the same time,which asks for verification requirements to ensure the structure safety. Therefore,it is necessary to carry out a systematic multi-level experimental study. In this paper,the building block approach (BBA) is used to investigate the multilevel composite material structures for spacecrafts. The advanced measurement technology is adopted based on digital image correlation (DIC) and piezoelectric and optical fiber sensors to measure the composite material structure deformation. The virtual experiment technology is applied to provide sufficient and reliable data for the evaluation of the composite material structures of spacecrafts. 展开更多
关键词 composite material structure SPACECRAFT multilevel test measurement evaluation
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Field measurement and evaluation of vibration in different areas of a metro depot 被引量:3
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作者 Feng Qingsong Zhang Yunlai +3 位作者 Jiang Jian Wang Ziyu Lei Xiaoyan Zhang Ling 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2022年第2期529-542,共14页
This paper presents a study of the characteristics of a railway vibration at three key sections containing different track structures in a metro depot.The results show that the vertical and horizontal vibration accele... This paper presents a study of the characteristics of a railway vibration at three key sections containing different track structures in a metro depot.The results show that the vertical and horizontal vibration acceleration levels are proportional to train speed.The Z-weighted vertical acceleration levels obtained showed that the vibration source strengths at the ballast foot of the testing line and the throat area were very close.The vibration attenuation at the repair line was larger than that of the testing line.In the throat area,the peak frequency of vibration obtained at the ballast foot(2.5 m)could be shifted to a lower frequency band by using polyurethane sleepers instead of standard concrete sleepers.Polyurethane sleepers can help to reduce vertical vibration in a frequency band of 0-10 Hz.The vibration levels would satisfy the limits given in the ISO2631-2-2003(2013)for any location more than 5 m away from the source at the testing line and 2.5 m away from the source at the repair line and throat area. 展开更多
关键词 field measurement metro depot peak frequency vibration acceleration environmental impacts
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The Evaluation of Measurement Uncertainty and Its Application in the Vacuum Pressure Measurement 被引量:1
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作者 Yulin Zhou Xin Quan Tieniu Yang 《Open Journal of Applied Sciences》 2015年第8期495-500,共6页
In order to accurately measure the pressure and the pressure difference between two points in the vacuum chamber, a large number of experimental data were used to research the performance of the three capacitance diap... In order to accurately measure the pressure and the pressure difference between two points in the vacuum chamber, a large number of experimental data were used to research the performance of the three capacitance diaphragm gauge and analysis the main influences of the uncertainly degree of pressure in the process. In this paper, three kind of uncertainty, such as the single uncertainty, the synthesis uncertainty and the expanded uncertainty of the three capacitance diaphragm gauges are introduced in detail in pressure measurement. The results show that the performance difference of capacitance diaphragm gauge can be very influential to the accuracy of the pressure difference measurement and the uncertainty of different pressure can be very influential to pressure measurement. That for accurately measuring pressure and pressure difference has certain reference significance. 展开更多
关键词 CAPACITANCE DIAPHRAGM GAUGES PRESSURE measurement measurement UNCERTAINTY
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Evaluation and Coordinated Development Measurement of the Construction of Marine Ecological Civilization in Coastal Areas—Taking Shandong Province, China as an Example 被引量:1
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作者 Jun Ma 《Journal of Geoscience and Environment Protection》 2020年第3期37-54,共18页
This paper selected 25 evaluation indexes from the three aspects of marine ecological economy, marine ecological environment and marine ecological society to construct an evaluation index system of the construction of... This paper selected 25 evaluation indexes from the three aspects of marine ecological economy, marine ecological environment and marine ecological society to construct an evaluation index system of the construction of coastal marine ecological civilization, using the analytic hierarchy process (AHP) and entropy value method to determine evaluation index weights, and measured the construction level of marine ecological civilization in Shandong Province during the period of 2006-2016. The results showed that the construction level of marine ecological civilization in Shandong Province during 2006-2016 as a whole is on the rise. In terms of the increase of the scores of each subsystem, the development of marine ecological society increased the most, followed by the development of marine ecological economy, while the development of marine ecological environment was relatively slow. This paper also analyzed the coordinated development level of the paired subsystems such as the marine ecological economy plus marine ecological environment, marine ecological society plus marine ecological environment and marine ecological economy plus marine ecological society in Shandong Province during the period of 2006-2016 by using the coupling coordination analysis model. The results showed that the level of coordinated development between the three pairs of subsystems has basically gone through the development process from low coordination to moderate coordination, and finally to high coordination. 展开更多
关键词 MARINE ECOLOGICAL CIVILIZATION evaluation Index System COORDINATED Development Empirical Analysis
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Measurement and Evaluation of Efficiency of Regional Technical Innovation Jiangsu Province 被引量:2
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作者 龚荒 王新宇 《Journal of China University of Mining and Technology》 2004年第1期26-32,41,共8页
The target system was built to evaluate the efficiency of technical innovation for 13 cities and three regions in Jiangsu province based on the data envelopment analysis. This paper comparatively analyzed the efficien... The target system was built to evaluate the efficiency of technical innovation for 13 cities and three regions in Jiangsu province based on the data envelopment analysis. This paper comparatively analyzed the efficiency of innovation and scaling return for each region in Jiangsu province. The projection analysis on production frontier face for inefficient regions was also performed. Evolving rules and regional difference of technical innovation system of Jiangsu province were explored. Some important results and suggestion were obtained. 展开更多
关键词 REGION technical innovation data envelopment analysis evaluation
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