期刊文献+
共找到554,470篇文章
< 1 2 250 >
每页显示 20 50 100
Research progress in digital auscultation:equipment and systems,characteristic parameters,and their application in diagnosis of pulmonary diseases and syndromes
1
作者 Shuyi ZHANG Tao JIANG Jiatuo XU 《Digital Chinese Medicine》 2025年第1期20-27,共8页
Traditional Chinese medicine(TCM)auscultation has a long history,and with advancements in equipment and analytical methods,the quantitative analysis of auscultation parameters has determined.However,the complexity and... Traditional Chinese medicine(TCM)auscultation has a long history,and with advancements in equipment and analytical methods,the quantitative analysis of auscultation parameters has determined.However,the complexity and diversity of auscultation,along with variations in devices,analytical methods,and applications,bring challenges to its standardization and deeper application.This review presents the advancements in auscultation equipment and systems,auscultation characteristic parameters,and their application in the diagnosis of pulmonary diseases and syndromes over the past 10 years,while also exploring the progress and challenges of current digital research of auscultation.This review also proposes the establishment of standardized protocols for the collection and analysis of auscultation data,the incorporation of advanced artificial intelligence(AI)auscultation analysis methods,and an exploration of the diagnostic utility of auscultatory features in pulmonary diseases and syndromes,so as to provide more precise decision support for intelligent diagnosis of pulmonary diseases and syndromes. 展开更多
关键词 Digital auscultation Equipment and systems characteristic parameters Pulmonary diseases and syndromes Intelligent diagnosis
暂未订购
Ocular biometric parameter characteristics and influence on refractive power in Chinese children
2
作者 Chao-Ying Ye Yu-Jia Liu +3 位作者 Wen-Qian Xing Jian-Min Shang Yang-Fan Xu Xiao-Mei Qu 《International Journal of Ophthalmology(English edition)》 2025年第12期2372-2379,共8页
AIM:To analyze ocular parameters and refractive status in children aged 3-12y and to explore differences in these parameters across age groups with identical refractive status for studying refractive progression.METHO... AIM:To analyze ocular parameters and refractive status in children aged 3-12y and to explore differences in these parameters across age groups with identical refractive status for studying refractive progression.METHODS:Demographic characteristics,cycloplegic refraction data,and ocular parameters of the participants were collected.Changes in ocular parameters were described according to different age groups.After adjusting for refractive factors,the relationship between age and ocular parameters was explored.Standard regression coefficients(β)obtained from multiple linear regressions were used to compare the magnitude of the effect of age on the parameters and ocular components on refractive power.RESULTS:Data were collected from the right eyes of 1504 participants.Lens thickness(LT)decreased with age,whereas the axial length(AL)and anterior chamber depth(ACD)increased.In the high-hyperopia group,changes in age were only associated with AL and LT.In the low-myopia group,the increase in age was also associated with corneal astigmatism.In the overall model,theβvalue for LT was the highest at 0.41,whereasβfor ACD and AL was significant in all groups except for the high-hyperopia group.Theβvalue of the LT on refractive power in children was slightly greater in the low age group than in the high age group.CONCLUSION:Among children with the same refractive status,the older the age,the longer the axis length and the thinner the lens.The lens affected refractive power in children in the younger age group more than in the older age group.The ocular parameter most affected by age was LT. 展开更多
关键词 pediatric eye conditions refractive error ocular parameters lens thickness axis length
原文传递
Corneal endothelial characteristics and biometric parameters in microcornea
3
作者 Xiang-Zheng Zhang Li Pei +8 位作者 Jia-Ning Shi Xi Lu Ran-Yi Ding Xiao-Wei Zhong Xin Wang Du-Lei Zou Wei-Yun Shi Can Zhao Ting Wang 《International Journal of Ophthalmology(English edition)》 2025年第10期1856-1863,共8页
AIM:To assess the corneal biometric parameters and endothelial cell characteristics in microcornea patients,and exploring their correlations.METHODS:This cross-sectional study included 28 patients of microcornea with ... AIM:To assess the corneal biometric parameters and endothelial cell characteristics in microcornea patients,and exploring their correlations.METHODS:This cross-sectional study included 28 patients of microcornea with uveal coloboma(MCUC),13 patients of microcornea without coloboma(MCNC),and 30 age-matched healthy individuals(the control group).Corneal biometric parameters such as axial length(AL),anterior chamber depth(ACD),and white-to-white corneal diameter(WTW)were measured using the IOL Master.The corneal endothelial cell density(ECD),percentage of hexagonal cells(6A),average cell area(AVE),maximum cell area(MAX),minimum cell area(MIN),cell area standard deviation(SD),and coefficient of variation(CV)were collected by specular microscopy.RESULTS:This study included MCUC and MCNC patients with age-and sex-matched controls.All patients exhibited significantly reduced WTW(MCUC:8.51±0.71 mm;MCNC:9.08±0.42 mm)and worse logMAR BCVA(MCUC 0.62±0.43;MCNC 0.46±0.28)compared to controls(both P<0.001).The ECD was 3106.32±336.80 cells/mm²in the MCUC group and 2906.92±323.53 cells/mm²in the MCNC group,both significantly higher than the control group(2647.43±203.06 cells/mm²,P<0.05).In contrast,the CV,AVE,SD,and ACD in the MCUC and MCNC groups were significantly lower compared to controls(P<0.01).In patients with microcornea,the WTW was negatively correlated with the ECD and 6A,but positively with the CV,MAX,AVE,and SD.The ACD was negatively linked to the ECD,but positively to the AVE.CONCLUSION:The corneal ECD and 6A are increased,while the CV is decreased in patients with microcornea,particularly in those accompanied by uveal coloboma.The ECD and morphology demonstrate close correlations with the WTW and ACD. 展开更多
关键词 MICROCORNEA corneal endothelial cell corneal biometric parameters uveal coloboma anterior chamber depth
原文传递
Damage characteristics and energy evolution law of high static load coalrock combination under the influence of dynamic load parameters
4
作者 TANG Long TU Shi-hao +4 位作者 TU Hong-sheng MIAO Kai-jun GUO Ben-huan ZHAO Hong-bin MA Jie-yang 《Journal of Central South University》 2025年第11期4397-4416,共20页
Based on MTS Landmark 370.50 rock dynamic and static load fatigue test system and acoustic emission(AE)monitoring method,the damage characteristics and energy evolution law of high static load coal-rock combination(CR... Based on MTS Landmark 370.50 rock dynamic and static load fatigue test system and acoustic emission(AE)monitoring method,the damage characteristics and energy evolution law of high static load coal-rock combination(CRC)under the influence of dynamic load parameters were studied.The main results are as follows:1)Dynamic load increases the rheological properties and damage fracture development of CRC.With the increase of the amplitude and frequency of the dynamic load,the number of dynamic load cycles required for the failure of the CRC decreases,the irreversible strain increases,and the failure of sample accelerates;2)The AE positioning events during the loading process of the specimen decrease with the increase of the dynamic load amplitude,and increase with the increase of the dynamic load frequency;3)The fractal dimension,total energy and cumulative elastic energy of the broken particles of the CRC increase with the increase of the amplitude and frequency of the dynamic load.The fractal dimension corresponding to the increase of the dynamic load frequency is larger,and the energy and cumulative elastic energy corresponding to the increase of the dynamic load amplitude are larger. 展开更多
关键词 dynamic-static load dynamic load parameters coal-rock combination damage and failure energy evolution
在线阅读 下载PDF
Parameter influence analysis and optimization of wheel–rail creepage characteristics in high-speed railway curves
5
作者 Bolun An Jiapeng Liu +3 位作者 Guang Yang Feng shou Liu Tong Shi Ming Zhai 《Railway Sciences》 2025年第1期37-51,共15页
Purpose–To investigate the influence of vehicle operation speed,curve geometry parameters and rail profile parameters on wheel–rail creepage in high-speed railway curves and propose a multi-parameter coordinated opt... Purpose–To investigate the influence of vehicle operation speed,curve geometry parameters and rail profile parameters on wheel–rail creepage in high-speed railway curves and propose a multi-parameter coordinated optimization strategy to reduce wheel–rail contact fatigue damage.Design/methodology/approach–Taking a small-radius curve of a high-speed railway as the research object,field measurements were conducted to obtain track parameters and wheel–rail profiles.A coupled vehicle-track dynamics model was established.Multiple numerical experiments were designed using the Latin Hypercube Sampling method to extract wheel-rail creepage indicators and construct a parameter-creepage response surface model.Findings–Key service parameters affecting wheel–rail creepage were identified,including the matching relationship between curve geometry and vehicle speed and rail profile parameters.The influence patterns of various parameters on wheel–rail creepage were revealed through response surface analysis,leading to the establishment of parameter optimization criteria.Originality/value–This study presents the systematic investigation of wheel–rail creepage characteristics under multi-parameter coupling in high-speed railway curves.A response surface-based parameter-creepage relationship model was established,and a multi-parameter coordinated optimization strategy was proposed.The research findings provide theoretical guidance for controlling wheel–rail contact fatigue damage and optimizing wheel–rail profiles in high-speed railway curves. 展开更多
关键词 High-speed railway Curve track Wheel-rail creepage parameter analysis Response surface methodology Optimization design
在线阅读 下载PDF
Characteristic Shear Strength Parameters Derived from Cone Penetration Test
6
作者 Erdi Myftaraga Olsi Koreta 《Journal of Civil Engineering and Architecture》 2025年第3期148-156,共9页
The interpretation and application of CPT(cone penetration test)results is characterized by considerable variability of data,either in measured or correlated parameters.According to the requirements of Eurocode 7 the ... The interpretation and application of CPT(cone penetration test)results is characterized by considerable variability of data,either in measured or correlated parameters.According to the requirements of Eurocode 7 the existing variability in soil properties has to be taken into account statistically during the determination of the characteristic values of each parameter.This should be done by selecting a cautious estimate of the value affecting the limit state.Obtaining the characteristic values of CPT measurements is not an easy task and on this aspect nor clear neither unified guidelines exist.This paper focuses in several approaches to characterize the cone resistance and the sleeve friction using simple statistical analysis,in order for these parameters to be applicable in design.Similar procedures are then applied to determine the characteristic values of correlated parameters from CPT such as the effective friction angle for sands and the undrained shear strength for clays.The resulting characteristic values of the considered parameters emphasize the fact that the prediction and the interpretation of characteristic values of soil properties is a complicated and biased procedure. 展开更多
关键词 Eurocode 7 CPTu(piezocone test) characteristic value friction angle undrained shear strength
在线阅读 下载PDF
Influence of geometric parameters on aerodynamic characteristics of serpentine convergent-divergent nozzle
7
作者 Xin WEI Xiaojuan SHI Honghu JI 《Chinese Journal of Aeronautics》 2025年第4期155-175,共21页
The serpentine convergent-divergent nozzle represents an optimal configuration for nextgeneration fighter aircraft characterized by low detectability and high thrust-to-weight ratio.In contrast to the serpentine conve... The serpentine convergent-divergent nozzle represents an optimal configuration for nextgeneration fighter aircraft characterized by low detectability and high thrust-to-weight ratio.In contrast to the serpentine convergent nozzle,such configuration offers increased design flexibility with additional parameters,leading to heightened interactions among these parameters.As such,it is crucial to reveal the influence of design parameters on the aerodynamic performance of the serpentine convergent-divergent nozzle and the multifactor interaction,as well as its mechanism.Therefore,the influence,interaction and sensitivity of parameters on the aerodynamic performance of the nozzle were numerically investigated using the orthogonal test method.Additionally,the influence mechanism of the convergence angle,throat aspect ratio,and axial length to inlet diameter on the flow characteristics of the nozzle was investigated in detail.The results show that the convergence angle is identified as the main factor affecting the aerodynamic parameters of the nozzle.As the convergence angle increases,the thrust coefficient,total pressure recovery coefficient and discharge coefficient gradually decrease.The interaction between throat aspect ratio and other parameters is obvious.Different design parameters affect the local loss and the friction loss by affecting the curvature and wetted perimeter area,resulting in different aerodynamic characteristics of serpentine convergent-divergent nozzle. 展开更多
关键词 Serpentine convergentdivergent nozzle AERODYNAMICS Orthogonal test method Flow characteristic Sensitivity analysis Multifactor interaction analysis
原文传递
Multimodal clinical parameters-based immune status associated with the prognosis in patients with hepatocellular carcinoma
8
作者 Yu-Zhou Zhang Yuan-Ze Tang +4 位作者 Yun-Xuan He Shu-Tong Pan Hao-Cheng Dai Yu Liu Hai-Feng Zhou 《World Journal of Gastrointestinal Oncology》 2026年第1期75-91,共17页
Hepatocellular carcinoma presents with three distinct immune phenotypes,including immune-desert,immune-excluded,and immune-inflamed,indicating various treatment responses and prognostic outcomes.The clinical applicati... Hepatocellular carcinoma presents with three distinct immune phenotypes,including immune-desert,immune-excluded,and immune-inflamed,indicating various treatment responses and prognostic outcomes.The clinical application of multi-omics parameters is still restricted by the expensive and less accessible assays,although they accurately reflect immune status.A comprehensive evaluation framework based on“easy-to-obtain”multi-model clinical parameters is urgently required,incorporating clinical features to establish baseline patient profiles and disease staging;routine blood tests assessing systemic metabolic and functional status;immune cell subsets quantifying subcluster dynamics;imaging features delineating tumor morphology,spatial configuration,and perilesional anatomical relationships;immunohistochemical markers positioning qualitative and quantitative detection of tumor antigens from the cellular and molecular level.This integrated phenomic approach aims to improve prognostic stratification and clinical decision-making in hepatocellular carcinoma management conveniently and practically. 展开更多
关键词 Hepatocellular carcinoma Immune status PHENOTYPE Multimodal parameters PROGNOSIS
暂未订购
Sociodemographic characteristics of suicide attempters treated in the emergency department and the effect of psychological care
9
作者 En-Sheng Tang Wan-Li Ren Hua Zou 《World Journal of Psychiatry》 2026年第1期116-124,共9页
BACKGROUND Appropriate care for individuals who attempt suicide and are admitted to the emergency department(ED)can prevent future suicidal behavior.It is vital to understand their sociodemographic characteristics and... BACKGROUND Appropriate care for individuals who attempt suicide and are admitted to the emergency department(ED)can prevent future suicidal behavior.It is vital to understand their sociodemographic characteristics and the effects of targeted psychological care.AIM To analyze sociodemographic characteristics of suicide attempters treated in the ED and evaluate the efficacy of psychological care.METHODS Data from 239 suicide attempters treated in the ED of the Central Hospital of Enshi Tujia and Miao Autonomous Prefecture(Hubei Province,China)between January 2021 and February 2025 were divided into 2:Control(n=108)and psychological care(n=131).The demographic characteristics and effects of the psychological care were analyzed.RESULTS The mean(±SD)age of the 239 patients[114 male(47.7%),125 female(52.3%)]was 26.25±9.3 years,of whom 122(45.2%)were single,117(48.9%)were married,and 106(44.4%)had secondary education.Thirty-eight(15.9%)patients had suicidal intent,with a mean of 1.26±0.59 suicide attempts each.Twenty-two(9.21%)patients had a family history of suicide,while 8(3.34%)had a family history of suicide attempt(s).Before intervention,mean Suicidal Intent Scale scores in the psychological nursing and control groups were 21.57±5.28 and 19.86±5.92,respectively(P>0.05).After 1 month of nursing intervention,the respective scores were 10.09±1.11 and 16.48±0.87(P<0.001);and the re-suicide rates were 11.45%(15/131)and 24.07%(26/108)(P<0.001).CONCLUSION Psychological care significantly reduces suicide risk;EDs should provide comprehensive mental health care. 展开更多
关键词 Emergency department Suicide attempts SUICIDE Psychological nursing Demographic characteristics
暂未订购
Influence of Geometric Parameters of Pre-Chamber on Mixture Formation in Marine Ammonia/Hydrogen Engines
10
作者 Shuzhe Yan Shengli Wei +2 位作者 Yuhao Lu Yuanchen Li Yuhan Li 《哈尔滨工程大学学报(英文版)》 2026年第1期277-291,共15页
Pre-chamber ignition technology can address the issue of uneven in-cylinder mixture combustion in large-bore marine engines.The impact of various pre-chamber structures on the formation of the mixture and jet flames w... Pre-chamber ignition technology can address the issue of uneven in-cylinder mixture combustion in large-bore marine engines.The impact of various pre-chamber structures on the formation of the mixture and jet flames within the pre-chamber is explored.This study performed numerical simulations on a large-bore marine ammonia/hydrogen pre-chamber engine prototype,considering pre-chamber volume,throat diameter,the distance between the hydrogen injector and the spark plug,and the hydrogen injector angle.Compared with the original engine,when the pre-chamber volume is 73.4 ml,the throat diameter is 14 mm,the distance ratio is 0.92,and the hydrogen injector angle is 80°.Moreover,the peak pressure in the pre-chamber increased by 23.1%,and that in the main chamber increased by 46.3%.The results indicate that the performance of the original engine is greatly enhanced by altering its fuel and pre-chamber structure. 展开更多
关键词 Pre-chamber ignition Ammonia/hydrogen fuel Pre-chamber mixture formation Jet characteristics Marine engine
在线阅读 下载PDF
Morphological characteristics and corresponding functional properties of homeostatic human microglia
11
作者 Pariya Khodabakhsh Olga Garaschuk 《Neural Regeneration Research》 2026年第3期1112-1113,共2页
Microglia,the resident immune cells of the central nervous system,exhibit a wide array of functional states,even in their so-called“homeostatic”condition,when they are not actively responding to overt pathological s... Microglia,the resident immune cells of the central nervous system,exhibit a wide array of functional states,even in their so-called“homeostatic”condition,when they are not actively responding to overt pathological stimuli.These functional states can be visualized using a combination of multi-omics techniques(e.g.,gene and protein expression,posttranslational modifications,mRNA profiling,and metabolomics),and,in the case of homeostatic microglia,are largely defined by the global(e.g.,genetic variations,organism’s age,sex,circadian rhythms,and gut microbiota)as well as local(specific area of the brain,immediate microglial surrounding,neuron-glia interactions and synaptic density/activity)signals(Paolicelli et al.,2022).While phenomics(i.e.,ultrastructural microglial morphology and motility)is also one of the key microglial state-defining parameters,it is known that cells with similar morphology can belong to different functional states. 展开更多
关键词 functional properties multi omics techniques protein expressionposttranslational modificationsmrna profilingand homeostatic human microglia morphological characteristics resident immune cells homeostatic microgliaare protein expression
暂未订购
Prestack seismic stochastic inversion based on statistical characteristic parameters 被引量:4
12
作者 Wang Bao-Li Lin Ying +1 位作者 Zhang Guang-Zhi Yin Xing-Yao 《Applied Geophysics》 SCIE CSCD 2021年第1期63-74,129,共13页
In the conventional stochastic inversion method,the spatial structure information of underground strata is usually characterized by variograms.However,effectively characterizing the heterogeneity of complex strata is ... In the conventional stochastic inversion method,the spatial structure information of underground strata is usually characterized by variograms.However,effectively characterizing the heterogeneity of complex strata is difficult.In this paper,multiple parameters are used to fully explore the underground formation information in the known seismic reflection and well log data.The spatial structure characteristics of complex underground reservoirs are described more comprehensively using multiple statistical characteristic parameters.We propose a prestack seismic stochastic inversion method based on prior information on statistical characteristic parameters.According to the random medium theory,this method obtains several statistical characteristic parameters from known seismic and logging data,constructs a prior information model that meets the spatial structure characteristics of the underground strata,and integrates multiparameter constraints into the likelihood function to construct the objective function.The very fast quantum annealing algorithm is used to optimize and update the objective function to obtain the fi nal inversion result.The model test shows that compared with the traditional prior information model construction method,the prior information model based on multiple parameters in this paper contains more detailed stratigraphic information,which can better describe complex underground reservoirs.A real data analysis shows that the stochastic inversion method proposed in this paper can effectively predict the geophysical characteristics of complex underground reservoirs and has a high resolution. 展开更多
关键词 prior information random medium theory statistical characteristic parameters stochastic inversion very fast quantum annealing
在线阅读 下载PDF
Synthetically quantitative evaluation function of characteristic parameters on CO_2 arc welding process 被引量:4
13
作者 俞建荣 蒋力培 +2 位作者 史耀武 孙振国 王军波 《China Welding》 EI CAS 2001年第1期19-26,共8页
The statistical probability and their variation regularity of the measurable characteristic parameters in the CO 2 arc welding droplet short circuiting transfer process have been studied. The statistical analysis sh... The statistical probability and their variation regularity of the measurable characteristic parameters in the CO 2 arc welding droplet short circuiting transfer process have been studied. The statistical analysis shows that the sensitivity of each characteristic parameter with regard to the variation of the short circuiting transfer process is different. The sensitivity of 4 kinds among these characteristic parameters is more intense than that of the short circuiting transfer frequency. In order to take account of the synthetic influence of these characteristic parameters, by means of the characteristic parameters synthetic value, a quantitative evaluation function is built up to describe and evaluate the short circuiting transfer process of CO 2 arc welding in real time. The testing shows that the evaluation function can give a suitable synthetic valuation for the short circuiting transfer process with a variety of welding variables. 展开更多
关键词 CO 2 arc welding process characteristic parameters quantitative evaluation function
在线阅读 下载PDF
LAD PARAMETER ESTIMATION of SaS BASED on SAMPLE CHARACTERISTIC FUNCTION
14
作者 陈高波 《科技信息》 2010年第25期I0028-I0028,I0027,共2页
Parameter estimation to alpha stable distribution is difficult for without a explicit probability density function. On the base of sample characteristic function,an iterative LAD parameter estimation algorithm for SaS... Parameter estimation to alpha stable distribution is difficult for without a explicit probability density function. On the base of sample characteristic function,an iterative LAD parameter estimation algorithm for SaS is discussed. The example illustrates that the algorithm is feasible and efficient. 展开更多
关键词 概率 密度函数 计算方法 迭代参数
在线阅读 下载PDF
Infl uence of structural parameters on dynamic characteristics and wind-induced buffeting responses of a super-long-span cable-stayed bridge 被引量:7
15
作者 Wang Hao Chen Chunchao +1 位作者 Xing Chenxi Li Aiqun 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2014年第3期389-399,共11页
A 3D finite element (FE) model for the Sutong cable-stayed bridge (SCB) is established based on ANSYS. The dynamic characteristics of the bridge are analyzed using a subspace iteration method. Based on recorded wi... A 3D finite element (FE) model for the Sutong cable-stayed bridge (SCB) is established based on ANSYS. The dynamic characteristics of the bridge are analyzed using a subspace iteration method. Based on recorded wind data, the measured spectra expression is presented using the nonlinear least-squares regression method. Turbulent winds at the bridge site are simulated based on the spectral representation method and the FFT technique. The influence of some key structural parameters and measures on the dynamic characteristics of the bridge are investigated. These parameters include dead load intensity, as well as vertical, lateral and torsional stiffness of the steel box girder. In addition, the influence of elastic stiffness of the connection device employed between the towers and the girder on the vibration mode of the steel box girder is investigated. The analysis shows that all of the vertical, lateral and torsional buffeting displacement responses reduce gradually as the dead load intensity increases. The dynamic characteristics and the structural buffeting displacement response of the SCB are only slightly affected by the vertical and torsional stiffness of the steel box girder, and the lateral and torsional buffeting displacement responses reduce gradually as the lateral stiffness increases. These results provide a reference for dynamic analysis and design of super-long-span cable-stayed bridges. 展开更多
关键词 cable-stayed bridge dynamic characteristics finite element (FE) method wind field simulation buffetingresponse parameter effects elastic connection device
在线阅读 下载PDF
The influence of MoS_2 on tribology characteristic parameter of Ni60A/MoS_2 composite lubricating coating 被引量:1
16
作者 ZHAO Yun-cai GE Shi-rong 《Journal of Coal Science & Engineering(China)》 2010年第1期94-98,共5页
The influence of MoS2 on the tribology characteristic parameter of Ni60A/MoS2 composite lubricating coating was researched on the UMT-2 fretting abrasion tester (USA) The result shows that with increasing content of... The influence of MoS2 on the tribology characteristic parameter of Ni60A/MoS2 composite lubricating coating was researched on the UMT-2 fretting abrasion tester (USA) The result shows that with increasing content of MoS2, the hardness curve of the composite coating decreases and the trend accelerates. Under the same experimental conditions, the mass loss of plasma spray composite coating without adding MoS2 iS 1.27×10^-2 mg. When the amount of MoS2 reaches 35%, the mass loss is 0.96×10^-2 mg. It can be seen that adding MoS2 phase can improve the wear resistance, the amplitude of which is close to 30%. The friction coefficient of plasma spray composite coating without adding MoS2 is 0.23. Adding MoSz could decrease the friction coefficient of the coating and presents a downtrend. When the mass fraction is 35%, the friction coefficient is the smallest (0.13), and the range is doubled. 展开更多
关键词 plasma spraying MoS2 phase composite lubricant coating tribology characteristic parameter friction coefficient
在线阅读 下载PDF
Relations Between Red Edge Characteristics and Agronomic Parameters of Crops 被引量:36
17
作者 TANGYan-Lin WANGRen-Chao HUANGJing-Feng 《Pedosphere》 SCIE CAS CSCD 2004年第4期467-474,共8页
The hyperspectral reflectance of the canopy and the leaves on the main stemfor six varieties, two each of rice corn, and cotton crops, were measured at different growth stageswith an ASD FieldSpec Pro FR^(TM) to analy... The hyperspectral reflectance of the canopy and the leaves on the main stemfor six varieties, two each of rice corn, and cotton crops, were measured at different growth stageswith an ASD FieldSpec Pro FR^(TM) to analyze red edge characteristics forleaf area indices (LAI),aboveground biomass, as well as the chlorophyll, carotenoid, and nitrogen content, emphasizingcomparative differences on the red edge parameters. The results showed a 'double peak' phenomenonfor the red edge of the canopy spectra but not for the leaves. There were 'increase' and 'decrease'change rules for the red edge position, lambda_r, the red edge slope, D lambda_r, and the red edgearea, S_r, of the canopy spectra for all 3 crops with a 'blue shift' for lambda_r of the leafspectra for all 3 crops as the development stages progressed. For rice, corn, and cotton the LAI andfresh leaf mass had highly significant correlations (P < 0.01) to the red edge parameters lambda_r,D lambda_r, and S_r of their canopy spectra. Additionally, for all crops the chlorophyll-a,chlorophyll-b, total chlorophyll, and carotenoid content of the leaves all had highly significant (P< 0.01) correlations to their lambda_r. For rice, the nitrogen content of the leaves in g kg^(-1)and phytomassfor a unit area of land in g m^(-2) also had a highly significant (P < 0.01)correlation to lambda_r, D lambda_r lambda_r, and S_r of the canopy spectra. 展开更多
关键词 agronomic parameter CROP red edge parameter correlation analysis
在线阅读 下载PDF
Some Characteristic Parameters of the Basic Components of the Solar Radio Emission 被引量:1
18
作者 Ji Shuchen (Beijing Astronomical Observatory, The Chinese Academy of Sciences, Beijing 100080, China) (Yunnan Observatory, The Chinese Academy of Sciences, Kunming 650011, China) (National Astronomical Observatories, The Chinese Academy of Sciences) $$ 《天文研究与技术》 CSCD 1999年第S1期457-460,共4页
Four basic components of the solar radio emission: the quiet sun, the slowly varying component (SVC), the radio burst and the ultra-fast varying component (UFVC) are studied. As their six characteristic parameters: ra... Four basic components of the solar radio emission: the quiet sun, the slowly varying component (SVC), the radio burst and the ultra-fast varying component (UFVC) are studied. As their six characteristic parameters: radiation source, brightness temperature, radiation lifetime, polarized radiation, radiation mechanism, and character of superposition are affirmed. 展开更多
关键词 RADIO Some characteristic parameters of the Basic Components Basic of the Solar Radio Emission
在线阅读 下载PDF
Variation characteristics of aquifer parameters induced by groundwater source heat pump operation under variable flow 被引量:5
19
作者 王松庆 张旭 《Journal of Central South University》 SCIE EI CAS 2011年第4期1272-1277,共6页
The variation characteristics of aquifer parameters,induced by groundwater source heat pump(GWSHP) operation under variable flow,were theoretically analyzed through a case study,in which the characteristics of buildin... The variation characteristics of aquifer parameters,induced by groundwater source heat pump(GWSHP) operation under variable flow,were theoretically analyzed through a case study,in which the characteristics of building air conditioning load were considered.The results,compared with the constant flow operation,indicate that the influence on the variations of porosity,hydraulic conductivity and confined water head is decreased by 48%,51% and 71%,respectively,under variable flow operation.The security of variable flow operation is superior to that of constant flow.It is also concluded that the climate region and function of the buildings are primary factors which affect the suitability of variable flow operation in GWSHP. 展开更多
关键词 groundwater source heat pump variation characteristic aquifer parameter variable flow
在线阅读 下载PDF
Field tests on mechanical characteristics and strength parameters of red-sandstone 被引量:4
20
作者 蒋建清 杨果林 《Journal of Central South University》 SCIE EI CAS 2010年第2期381-387,共7页
Large-scale field shear tests on ten specimens of the red-sandstone embankment at a highway in Hunan,China,were performed to examine mechanical characteristics and parameters of red-sandstone.The curves of thrust-disp... Large-scale field shear tests on ten specimens of the red-sandstone embankment at a highway in Hunan,China,were performed to examine mechanical characteristics and parameters of red-sandstone.The curves of thrust-displacement,failure mode,and shear strength parameters for red-sandstone with different water contents,different compactions,and different grain size distributions were obtained from the tests.A practical procedure of in-situ test for red-sandstone embankment was proposed to normalize the test equipment and test steps.Based on three-dimensional thrust-sliding limit equilibrium method,the formulas for calculating strength parameters of red-sandstone considering three-dimensional sliding surface were inferred.The results show that red-sandstone has typical complete curves of stress-strain,strain softening,which are caused by the special structure of red-sandstone;water content and compaction are important factors for strength and failure mode of red-sandstone;The average value of cohesion and internal friction angle of the specimens calculated by three-dimensional technique are 21.56 kPa and 29.29°,respectively,and those by traditional two-dimensional method are 25.52 kPa and 33.76°,respectively. 展开更多
关键词 red-sandstone large-scale field test mechanical characteristic strength parameter
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部