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Measured dynamic load distribution within the in situ axlebox bearing of high-speed trains under polygonal wheel–rail excitation
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作者 Yu Hou Xi Wang +4 位作者 Jiaqi Wei Menghua Zhao Wei Zhao Huailong Shi Chengyu Sha 《Railway Engineering Science》 EI 2024年第4期444-460,共17页
The dynamic load distribution within in-service axlebox bearings of high-speed trains is crucial for the fatigue reliability assessment and forward design of axlebox bearings. This paper presents an in situ measuremen... The dynamic load distribution within in-service axlebox bearings of high-speed trains is crucial for the fatigue reliability assessment and forward design of axlebox bearings. This paper presents an in situ measurement of the dynamic load distribution in the four rows of two axlebox bearings on a bogie wheelset of a high-speed train under polygonal wheel–rail excitation. The measurement employed an improved strain-based method to measure the dynamic radial load distribution of roller bearings. The four rows of two axlebox bearings on a wheelset exhibited different ranges of loaded zones and different means of distributed loads. Besides, the mean value and standard deviation of measured roller–raceway contact loads showed non-monotonic variations with the frequency of wheel–rail excitation. The fatigue life of the four bearing rows under polygonal wheel–rail excitation was quantitatively predicted by compiling the measured roller–raceway contact load spectra of the most loaded position and considering the load spectra as input. 展开更多
关键词 High-speed train Axlebox bearing Dynamic load distribution In situ measurement Polygonal wheel–rail excitation
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Data-driven methods for predicting the representative temperature of bridge cable based on limited measured data
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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
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A Synergistic Multi-Attribute Decision-Making Method for Educational Institutions Evaluation Using Similarity Measures of Possibility Pythagorean Fuzzy Hypersoft Sets
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作者 Khuram Ali Khan Saba Mubeen Ishfaq +1 位作者 Atiqe Ur Rahman Salwa El-Morsy 《Computer Modeling in Engineering & Sciences》 SCIE EI 2025年第1期501-530,共30页
Due to the numerous variables to take into account as well as the inherent ambiguity and uncertainty,evaluating educational institutions can be difficult.The concept of a possibility Pythagorean fuzzy hypersoft set(pP... Due to the numerous variables to take into account as well as the inherent ambiguity and uncertainty,evaluating educational institutions can be difficult.The concept of a possibility Pythagorean fuzzy hypersoft set(pPyFHSS)is more flexible in this regard than other theoretical fuzzy set-like models,even though some attempts have been made in the literature to address such uncertainties.This study investigates the elementary notions of pPyFHSS including its set-theoretic operations union,intersection,complement,OR-and AND-operations.Some results related to these operations are also modified for pPyFHSS.Additionally,the similarity measures between pPyFHSSs are formulated with the assistance of numerical examples and results.Lastly,an intelligent decision-assisted mechanism is developed with the proposal of a robust algorithm based on similarity measures for solving multi-attribute decision-making(MADM)problems.A case study that helps the decision-makers assess the best educational institution is discussed to validate the suggested system.The algorithmic results are compared with the most pertinent model to evaluate the adaptability of pPyFHSS,as it generalizes the classical possibility fuzzy set-like theoretical models.Similarly,while considering significant evaluating factors,the flexibility of pPyFHSS is observed through structural comparison. 展开更多
关键词 Hypersoft set Pythagorean fuzzy hypersoft set computational complexity multi-attribute decision-making optimization similarity measures uncertainty
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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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Voices that matter:The impact of patient-reported outcome measures on clinical decision-making
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作者 Naveen Jeyaraman Madhan Jeyaraman +2 位作者 Swaminathan Ramasubramanian Sangeetha Balaji Sathish Muthu 《World Journal of Methodology》 2025年第2期54-61,共8页
The critical role of patient-reported outcome measures(PROMs)in enhancing clinical decision-making and promoting patient-centered care has gained a profound significance in scientific research.PROMs encapsulate a pati... The critical role of patient-reported outcome measures(PROMs)in enhancing clinical decision-making and promoting patient-centered care has gained a profound significance in scientific research.PROMs encapsulate a patient's health status directly from their perspective,encompassing various domains such as symptom severity,functional status,and overall quality of life.By integrating PROMs into routine clinical practice and research,healthcare providers can achieve a more nuanced understanding of patient experiences and tailor treatments accordingly.The deployment of PROMs supports dynamic patient-provider interactions,fostering better patient engagement and adherence to tre-atment plans.Moreover,PROMs are pivotal in clinical settings for monitoring disease progression and treatment efficacy,particularly in chronic and mental health conditions.However,challenges in implementing PROMs include data collection and management,integration into existing health systems,and acceptance by patients and providers.Overcoming these barriers necessitates technological advancements,policy development,and continuous education to enhance the acceptability and effectiveness of PROMs.The paper concludes with recommendations for future research and policy-making aimed at optimizing the use and impact of PROMs across healthcare settings. 展开更多
关键词 Patient-reported outcome measures Clinical decision-making Patient-centered care Healthcare technology Data management Policy development
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Variations in quantifying patient reported outcome measures to estimate treatment effect
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作者 Sathish Muthu Srujun Vadranapu 《World Journal of Methodology》 2025年第2期44-53,共10页
In the practice of healthcare,patient-reported outcomes(PROs)and PRO measures(PROMs)are used as an attempt to observe the changes in complex clinical situations.They guide us in making decisions based on the evidence ... In the practice of healthcare,patient-reported outcomes(PROs)and PRO measures(PROMs)are used as an attempt to observe the changes in complex clinical situations.They guide us in making decisions based on the evidence regarding patient care by recording the change in outcomes for a particular treatment to a given condition and finally to understand whether a patient will benefit from a particular treatment and to quantify the treatment effect.For any PROM to be usable in health care,we need it to be reliable,encapsulating the points of interest with the potential to detect any real change.Using structured outcome measures routinely in clinical practice helps the physician to understand the functional limitation of a patient that would otherwise not be clear in an office interview,and this allows the physician and patient to have a meaningful conver-sation as well as a customized plan for each patient.Having mentioned the rationale and the benefits of PROMs,understanding the quantification process is crucial before embarking on management decisions.A better interpretation of change needs to identify the treatment effect based on clinical relevance for a given condition.There are a multiple set of measurement indices to serve this effect and most of them are used interchangeably without clear demarcation on their differences.This article details the various quantification metrics used to evaluate the treatment effect using PROMs,their limitations and the scope of usage and implementation in clinical practice. 展开更多
关键词 Patient-reported outcome measures Treatment effect Minimal clinical important difference Patient-accepted symptom state Minimum detectable change ORTHOPEDICS
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Measurement of Rural Inclusive Financial Development and Analysis of Spatial Effects on Anti-poverty 被引量:2
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作者 Yongbin LU Chunmei WANG Weican QU 《Asian Agricultural Research》 2017年第1期33-40,46,共9页
Based on two dimensions of supply and demand,we use six indicators to establish a rural inclusive financial development index and evaluate the development of China's rural inclusive finance. We use spatial panel d... Based on two dimensions of supply and demand,we use six indicators to establish a rural inclusive financial development index and evaluate the development of China's rural inclusive finance. We use spatial panel data model to examine the relationship between financial inclusion and rural poverty. Results show that:( i) both the rural inclusive finance and rural residents' per capita consumption present spatial clustering feature and show significant spatial correlation;( ii) the development of rural inclusive finance has significant spatial effect on poverty alleviation along time and space dimensions. In this study,the paper puts forward policy recommendations on strengthening the rural financial resources flow and constructing diversified rural inclusive financial system. 展开更多
关键词 Inclusive financial Rural finance anti-poverty Spatial effect
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Application and dynamical performance simulation of tooth surface measured data of hypoid gear 被引量:2
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作者 XU Zhong-si FENG Lei LEI Hong-xia 《Journal of Measurement Science and Instrumentation》 CAS 2014年第2期1-8,共8页
The tooth surface shape of hypoid gear is very complicated, and tooth surface accuracy of hypoid gear can be measured by using the latticed measurement and scanning measurement. Advantages and disadvantages of the two... The tooth surface shape of hypoid gear is very complicated, and tooth surface accuracy of hypoid gear can be measured by using the latticed measurement and scanning measurement. Advantages and disadvantages of the two measurement patterns are compared and application of their measurement data on hypoid gear's quality management is analyzed. How to use these measurement data to simulate the dynamical performance of hypoid gear is researched, and the intelligent predicton of the dynamical performance indexes of contact spot, root stress, vibration exciting forces and load distribution and hertz contact stress on the tooth surface are carried out. This research work has an important guiding sense to design and ma- chine hypoid gear with low vibration and noise. 展开更多
关键词 hypoid gear latticed measurement scanning measurement tooth surface dynamical performance simulation
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Assessing the influence of the minimum measured diameter on forest spatial patterns and nearest neighborhood relationships 被引量:1
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作者 LI Yuan-fa YANG Hai-peng +2 位作者 WANG Hong-xiang YE Shao-ming LIU Wen-zhen 《Journal of Mountain Science》 SCIE CSCD 2019年第10期2308-2319,共12页
Forest structure analysis is important for understanding the properties and development of a forest community,and its outcomes can be influenced by how trees are measured in sampled plots.Although there is a general c... Forest structure analysis is important for understanding the properties and development of a forest community,and its outcomes can be influenced by how trees are measured in sampled plots.Although there is a general consensus on the height at which tree diameter should be measured[1.3 m:diameter at breast height(DBH)],the minimum measureddiameter(MMD)often varies in different studies.In this study,we assumed that the outcomes of forest structure analysis can be influenced by MMD and,to this end,we applied g(r)function and stand spatial structural parameters(SSSPs)to investigate how different MMDs affect forest spatial structure analysis in two pine-oak mixed forests(30 and 57 years old)in southwest China and one old-growth oak forest(>120years old)from northwest China.Our results showed that 1)MMD was closely related to the distribution patterns of forest trees.Tree distribution patterns at each observational scale(r=0-20 m)tended tobecome random as the MMD increased.The older the community,the earlier this random distribution pattern appeared.2)As the MMD increased,neighboring trees became more regularly distributed around a reference tree.In most cases,however,nearest neighbors of a reference tree were randomly distributed.3)Tree species mingling decreased with increasing diameter,but it decreased slowly in older forests.4)No correlations can be found between individual tree size differentiation and MMD.We recommend that comparisons of spatial structures between communities would be more effective if using a unified MMD criterion. 展开更多
关键词 Distribution patterns Minimum measured DIAMETER Mixed FOREST Nearest NEIGHBOR analysis Species MINGLING Uniform angle index
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Research on the Explosion Temperature Response of Fuel Air Explosive Measured by Colorimetric Pyrometer 被引量:1
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作者 刘庆明 白春华 《Defence Technology(防务技术)》 SCIE EI CAS 2010年第1期59-64,共6页
An infrared colorimetric radiation thermometrical system was established based on the theory of optical radiation. The dynamic temperature history of fuel air explosive (FAE) was measured to obtain the temperature res... An infrared colorimetric radiation thermometrical system was established based on the theory of optical radiation. The dynamic temperature history of fuel air explosive (FAE) was measured to obtain the temperature responses of primary initiation FAE and secondary initiation FAE in real time. And the characteristics of their temperature history curves were compared and analyzed. The results show that the primary initiation FAE has higher explosion temperature and longer duration compared to the secondary initiation FAE. 展开更多
关键词 mechanics of explosion explosion temperature fuel air explosive radiation pyrometry colorimetric pyrometer infrared temperature measurement
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The Realistic Dilemma and Countermeasures of Anti-poverty Industrial-capacity Cooperation Between China and Africa 被引量:1
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作者 Wang Zhizhang Zheng Shiyan 《Contemporary Social Sciences》 2020年第5期47-69,共23页
Poverty eradication is an important goal of African social development.China has always attached great importance to exchanges and cooperation with African countries in the field of poverty reduction and with the deep... Poverty eradication is an important goal of African social development.China has always attached great importance to exchanges and cooperation with African countries in the field of poverty reduction and with the deepening of the practice and understanding of China-Africa anti-poverty cooperation,industrial-capacity cooperation has become a new theme of poverty reduction and development in China-Africa cooperation at the 2016 Forum on China Africa Cooperation(FOCAC)—Africa-China Poverty Reduction and Development Conference.Through combing and analysis of relevant literature and data,we found that China-Africa industrial-capacity cooperation,which is based on infrastructure construction,industrial park construction and trade exchanges,has played an important role in poverty reduction and development in African countries by facilitating industrialization and agricultural modernization,enhancing endogenous motivation for poverty alleviation,and improving the sustainable livelihood of poor people.At present,in the practice of anti-poverty industrial-capacity cooperation between China and Africa,there are still difficulties such as weak anti-poverty foundation and cooperation paths yet to be optimized.Meanwhile,it is also faced with a series of risks and challenges such as intensified international competition.In order to improve the cooperation between China and Africa,promote anti-poverty benefits,optimize the implementation paths,and better solve the dilemma of cooperation,we put forward relevant countermeasures and suggestions from the four dimensions of government,enterprises,think tanks and people. 展开更多
关键词 China and Africa industrial-capacity cooperation anti-poverty realistic dilemma COUNTERmeasurES
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Reversion of weak-measured quantum entanglement state 被引量:1
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作者 Shao-Jiang Du Yonggang Peng +3 位作者 Hai-Ran Feng Feng Han Lian-Wu Yang Yu-Jun Zheng 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第7期308-312,共5页
We theoretically study the reversible process of quantum entanglement state by means of weak measurement and corresponding reversible operation.We present a protocol of the reversion operation in two bodies based on t... We theoretically study the reversible process of quantum entanglement state by means of weak measurement and corresponding reversible operation.We present a protocol of the reversion operation in two bodies based on the theory of reversion of single photon and then expend it in quantum communication channels.The theoretical results demonstrate that the protocol does not break the information transmission after a weak measurement and a reversible measurement with the subsequent process in the transmission path.It can reverse the perturbed entanglement intensity evolution to its original state.Under the condition of different weak measurement intensity the protocol can reverse the perturbed quantum entanglement system perfectly.In the process we can get the classical information described by information gain from the quantum system through weak measurement operation.On the other hand,in order to realize complete reversibility,the classical information of the quantum entanglement system must obey a limited range we present in this paper in the reverse process. 展开更多
关键词 quantum entanglement weak measurement reversion operation information gain and reversibility
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Exploring China's Western and Central County Systems Performance Measured by Outcomes Framework Scores-A Cross-sectional Survey of Routine Healthcare Data
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作者 石军 张亮 +3 位作者 刘岳 王江波 Chris Scarf 熊巨洋 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2011年第4期419-425,共7页
This study was designed to measure the performance of county health systems in central and western China utilizing routine healthcare data.Drawing on a literature review and expert consultation,the study established a... This study was designed to measure the performance of county health systems in central and western China utilizing routine healthcare data.Drawing on a literature review and expert consultation,the study established a theoretical framework and an indicator system for performance review.Questionnaires were designed and disseminated to collect empirical data on health system performance in four counties of two central and western provinces.Quantitative data were subjected to descriptive statistical analysis through SPSS12.0.Three dimensions were introduced in the performance review framework—health outcomes,financial risk protection and consumer and provider satisfaction.Health outcomes were assessed from four secondary indicators:infant mortality rate;maternal mortality rate;under-5 child mortality rate;and the incidence of Class A and Class B notifiable diseases.Financial risk was assessed using two secondary indicators:the proportion of the cost of inpatient care that was reimbursed under the New Cooperative Medical System(NCMS) insurance scheme,and the rate of NCMS funds utilization.The assessment of satisfaction was made using two secondary indicators:the overall satisfaction of local residents with healthcare services,and the satisfaction of health practitioners at the township and village level.The study indicated better health system performance in the two counties in Chongqing than those in Shanxi.It was concluded that outcome framework scores can fairly reveal performance differences among county health systems in central and western China,and can provide practical evidence for optimizing the operation and inputs of county health systems.Caution needs to be exercised in generalizing such performance outcomes as many factors such as spending and organization that contribute to county health system performance were not included in the study. 展开更多
关键词 COUNTY health systems performance OUTCOME measurement
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Drilling-based measuring method for the c-φ parameter of rock and its field application 被引量:3
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作者 Bei Jiang Fenglin Ma +5 位作者 Qi Wang Hongke Gao Dahu Zhai Yusong Deng Chuanjie Xu Liangdi Yao 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第1期65-76,共12页
The technology of drilling tests makes it possible to obtain the strength parameter of rock accurately in situ. In this paper, a new rock cutting analysis model that considers the influence of the rock crushing zone(R... The technology of drilling tests makes it possible to obtain the strength parameter of rock accurately in situ. In this paper, a new rock cutting analysis model that considers the influence of the rock crushing zone(RCZ) is built. The formula for an ultimate cutting force is established based on the limit equilibrium principle. The relationship between digital drilling parameters(DDP) and the c-φ parameter(DDP-cφ formula, where c refers to the cohesion and φ refers to the internal friction angle) is derived, and the response of drilling parameters and cutting ratio to the strength parameters is analyzed. The drillingbased measuring method for the c-φ parameter of rock is constructed. The laboratory verification test is then completed, and the difference in results between the drilling test and the compression test is less than 6%. On this basis, in-situ rock drilling tests in a traffic tunnel and a coal mine roadway are carried out, and the strength parameters of the surrounding rock are effectively tested. The average difference ratio of the results is less than 11%, which verifies the effectiveness of the proposed method for obtaining the strength parameters based on digital drilling. This study provides methodological support for field testing of rock strength parameters. 展开更多
关键词 Digital drilling Rock crushing zone c-u parameter measurement method Field application
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HealthMeasures患者报告结局报告清单的解读
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作者 臧娴 宗旭倩 +4 位作者 袁长蓉 王玲 吴傅蕾 张雯 黄青梅 《护士进修杂志》 2024年第10期1088-1092,共5页
美国匹兹堡大学和HealthMeasures指导委员会及PROMIS健康组织标准委员会共同发表了HealthMeasures患者报告结局报告清单,旨在促进不同患者报告结局测量工具的标准化报告,帮助研究人员提高工具报告质量及结果解释的准确性,进一步改善跨... 美国匹兹堡大学和HealthMeasures指导委员会及PROMIS健康组织标准委员会共同发表了HealthMeasures患者报告结局报告清单,旨在促进不同患者报告结局测量工具的标准化报告,帮助研究人员提高工具报告质量及结果解释的准确性,进一步改善跨研究间的比较分析。本文对HealthMeasures患者报告结局报告清单的主要内容进行介绍和解读,以期为中国患者报告结局研究者提供参考和借鉴。 展开更多
关键词 患者报告结局 报告清单 测量工具 标准化 解读
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Higher-Order Fluctuations and Measured Phase Operators in the Squeezed Thermal States
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作者 Dong Chuanhua (College of Science, Shanghai University) 《Advances in Manufacturing》 SCIE CAS 1999年第1期42-46,共5页
We study the higher order fluctuations and squeezing of quadrature operators in the squeezed thermal states. In terms of measured phase operators, we discuss the fluctuations and squeezing of phases in these states.... We study the higher order fluctuations and squeezing of quadrature operators in the squeezed thermal states. In terms of measured phase operators, we discuss the fluctuations and squeezing of phases in these states. We conclude that the condition of higher order squeezing for quadrature components of the field is order independent and the fluctuations of measured phase operators are temperature independent. 展开更多
关键词 squeezed thermal state higher order squeezing measured phase operator
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An Improved Method for Correction of Air Temperature Measured Using Different Radiation Shields
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作者 CHENG Xinghong SU Debin +6 位作者 LI Deping CHEN Lu XU Wenjing YANG Meilin LI Yongcheng YUE Zhizhong WANG Zijing 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2014年第6期1460-1468,共9页
The variation of air temperature measurement errors using two different radiation shields (DTR502B Vaisala,Finland,and HYTFZ01,Huayun Tongda Satcom,China) was studied.Datasets were collected in the field at the Daxi... The variation of air temperature measurement errors using two different radiation shields (DTR502B Vaisala,Finland,and HYTFZ01,Huayun Tongda Satcom,China) was studied.Datasets were collected in the field at the Daxing weather station in Beijing from June 2011 to May 2012.Most air temperature values obtained with these two commonly used radiation shields were lower than the reference records obtained with the new Fiber Reinforced Polymers (FRP) Stevenson screen.In most cases,the air temperature errors when using the two devices were smaller on overcast and rainy days than on sunny days; and smaller when using the imported rather than the Chinese shield.The measured errors changed sharply at sunrise and sunset,and reached maxima at noon.Their diurnal variation characteristics were,naturally,related to changes in solar radiation.The relationships between the record errors,global radiation,and wind speed were nonlinear.An improved correction method was proposed based on the approach described by Nakamura and Mahrt (2005) (NM05),in which the impact of the solar zenith angle (SZA) on the temperature error is considered and extreme errors due to changes in SZA can be corrected effectively.Measurement errors were reduced significantly after correction by either method for both shields.The error reduction rate using the improved correction method for the Chinese and imported shields were 3.3% and 40.4% higher than those using the NM05 method,respectively. 展开更多
关键词 radiation shield measurement error impacts of solar zenith angle improved correction method
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Fluctuations and Squeezing for Measured Phase Operators of the J-C Model in the Kerr Medium
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作者 许毅 董传华 李可 《Journal of Shanghai University(English Edition)》 CAS 2004年第2期148-154,共7页
By using the theory of measured phase operator proposed by Barnett and Pegg, dynamic properties of the phase of a field are studied. The time evolution and squeezing of measured phase operators of a coherent field int... By using the theory of measured phase operator proposed by Barnett and Pegg, dynamic properties of the phase of a field are studied. The time evolution and squeezing of measured phase operators of a coherent field interacting with a two-level atom in the cavity with or without the Kerr medium are investigated. The influences of virtual cavity field on squeezing of measured phase operator are studied. Our numerical results show that the squeezing effects are clearly influenced by Kerr medium parameters, the field intensity, and the detuning. Moreover, the influence of the virtual-photon field makes more quantum noise in the evolution of measured phase operators. Key words Jaynes-Cummings model (JCM) - Kerr medium - measured phase operator - squeezing - virtual photon PACS 2001 4250Dv 展开更多
关键词 Jaynes-Cummings model (JCM) Kerr medium measured phase operator SQUEEZING virtual photon
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A portable instrument for measurement of atmospheric O_(x) and NO_(2) based on cavity ring-down spectroscopy 被引量:1
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作者 Jinzhao Tong Renzhi Hu +5 位作者 Changjin Hu Haotian Cai Chuan Lin Jiawei Wang Liang Chen Pinhua Xie 《Atmospheric and Oceanic Science Letters》 CSCD 2024年第6期21-25,共5页
Atmospheric O_(x)(nitrogen dioxide(NO_(2))+ozone(O_(3)))can better reflect the local and regional change character-istics of oxidants compared to O_(3)alone,so obtaining O_(x)accurately and rapidly is the basis for ev... Atmospheric O_(x)(nitrogen dioxide(NO_(2))+ozone(O_(3)))can better reflect the local and regional change character-istics of oxidants compared to O_(3)alone,so obtaining O_(x)accurately and rapidly is the basis for evaluating the O_(3)production rate.Furthermore,O_(x)has proved to be a more representative indicator and can serve as a reflection of pollution prevention efficacy.A portable instrument for measuring atmospheric O_(x)and NO_(2)based on cavity ring-down spectroscopy(O_(x)/NO_(2)-CRDS)was developed in this work.The NO_(2)concentration is accurately mea-sured according to its absorption characteristic at 407.86 nm.Ambient O_(3)is converted into NO_(2)by chemical titration of high concentrations of nitrogen oxide(NO),and the O_(3)conversion efficiencies obtained are nearly 99%.The detection limit of the O_(x)/NO_(2)-CRDS system for O_(x)is 0.024 ppbv(0.1 s),and the overall uncertainty of the instrument is±6%.Moreover,the Kalman filtering technique was applied to improve the measurement accuracy of O_(x)/NO_(2)-CRDS.The system was applied in a comprehensive field observation campaign at Hefei Sci-ence Island from 26 to 30 September 2022,and the time concentration series and change characteristics of O_(x)and NO_(2)were obtained for five days.The measured O_(x)concentrations were compared with those of two com-mercial instruments,and the consistency was good(R^(2)=0.98),indicating that this system can be deployed to accurately and rapidly obtain the concentrations of atmospheric O_(x)and NO_(2).It will be a useful tool for assessing the atmospheric oxidation capacity and controlling O_(3)pollution. 展开更多
关键词 Cavity ring-down OXIDANT OZONE Portable measurement
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New Approach for Measured Surface Localization Based on Umbilical Points
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作者 Xiao-Ping Xiao Ming Yin +2 位作者 Liang Heng Guo-Fu Yin Zi-Sheng Li 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2017年第5期1203-1215,共13页
Measured surface localization (MSL) is one of the key essentials for the assessment of form error in pre- cision manufacturing. Currently, the researches on MSL have focused on the corresponding relation search betw... Measured surface localization (MSL) is one of the key essentials for the assessment of form error in pre- cision manufacturing. Currently, the researches on MSL have focused on the corresponding relation search between two surfaces, the performance improvement of localization algorithms and the uncertainty analysis of localization. However, low efficiency, limitation of localization algo- rithms and mismatch of multiple similarities of feature points with no prior are the common disadvantages for MSL. In order to match feature points quickly and fulfill MSL efficiently, this paper presents a new localization approach for measured surfaces by extracting the generic umbilics and estimating their single complex variables, describing the match methods of ambiguous relation at umbilics, presenting the initial localization process of one pair matched points, refining MSL on the basis of obtained closet points for some measured points by the improvement directed projection method. In addition, the proposed algorithm is simulated in two different types of surfaces,two different localization types and multiple similar sur- faces, also tested with the part of B-spline surface machined and bottle mould with no knowledge, finally the initial and accurate rigid body transformation matrix, localization errors between two surfaces and execution time are got. The experimental results show that the pro- posed method is feasible, more accurate in localization and high in efficiency. The proposed research can not only improve the accuracy and performance of form error assessment, but also provide an effective guideline for the integration of different types of measured surfaces. 展开更多
关键词 measured surface localization Umbilicalpoints and complex variable Similar surface patchesInitial and accurate localization
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