检索结果-南通市图书馆

Crack Fault Classification for Planetary Gearbox Based on Feature Selection Technique and K-means Clustering Method

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2018年第1期31卷 242-252页

作者： Li-ming Wang Yi-min shao State Key Laboratory of Mechanical Transmission Chongqing University

During the condition monitoring of a planetary gearbox, features are extracted from raw data for a fault ***, different features have different sensitivity for identifying different fault types, and thus, the selection of a sensitive feature subset from an entire feature set and retaining as much of the class discriminatory information as possible has a directly effect on the accuracy of the classification results. In this paper, an improved hybrid feature selection technique(IHFST) that combines a distance evaluation technique(DET), Pearson’s correlation analysis, and an ad hoc technique is proposed. In IHFST, a temporary feature subset without irrelevant features is first selected according to the distance evaluation criterion of DET, and the Pearson’s correlation analysis and ad hoc technique are then employed to find and remove redundant features in the temporary feature subset, respectively, and hence,a sensitive feature subset without irrelevant or redundant features is selected from the entire feature set. Further, the k-means clustering method is applied to classify the different kinds of health conditions. The effectiveness of the proposed method was validated through several experiments carried out on a planetary gearbox with incipient cracks seeded in the tooth root of the sun gear, planet gear, and ring gear. The results show that the proposed method can successfully distinguish the different health conditions of a planetary gearbox, and achieves a better classification performance than other methods. This study proposes a sensitive feature subset selection method that achieves an obvious improvement in terms of the accuracy of the fault classification.

关键词： Planetary gearbox Gear crack Feature selection technique K-means classification

Emergence and Shaping of Huangmei Opera： From A Genetic View

在线全文

学校读者我要写书评

暂无评论

学术界 2013年第9期 298-303页

作者： shao min Department of Chinese Anqing Normal University Anqing Anhui 246011

From a genetic view,the emergence of Huangmei Opera is closely related to the historical and cultural features of Wanjiang region and the bordering Wan-E-Gan area. The natural and human geography,economic production features and folk culture features of the Wanjiang historical and cultural core area marvelously facilitate the emergence of this fantastic art. Although Wangjiang history and culture alone does not necessarily bring about Huangmei Opera,it is indispensable for its emergence. Therefore,it is beneficial for its inheritance,innovation and re-emergence to combine Huangmei Opera and other Wanjiang historical cultural phenomena and conduct some necessary experiment.

关键词：遗传学梅历史文化文化特征人文地理生产特点文化现象皖江

A copper-based metal-organic framework for upgrading natural gas through the recovery of C_(2)H_(6) and C_(3)H_(8)

在线全文

学校读者我要写书评

暂无评论

Green Chemical Engineering 2023年第1期4卷 81-87页

作者： shao-min Wang Qing-Yuan Yang School of Chemical Engineering and Technology Xi'an Jiaotong UniversityXi'an710049China

Natural gas processing involves the separation of higher hydrocarbons(C2–C3)from methane,which is an important and energy-intensive *** this paper,we present a comprehensive study of an innovative copper-based MOF(Cu-MOF)for the separation of propane and ethane from *** material exhibits a high adsorption capacity and selectivity for C2–C3 hydrocarbons over methane,which is primarily due to its preferential C2–C3 hydrocarbon *** adsorption isotherms at ambient conditions showed a remarkable uptake of C_(3)H_(8)of 134.0 cm^(3)/g,as well as excellent selectivity of 204 and 9 for C_(3)H_(8)/CH_(4)and C_(2)H_(6)/CH_(4).According to the theoretical calculations,differences in van der Waals interactions and polarizability of the guest molecules were responsible for influencing separation *** addition,we conducted adsorption kinetic experiments,dynamic breakthrough,and cycling experiments to further examine the separation ***,this research establishes an energy-efficient adsorbent for upgrading natural gas.

关键词： Natural gas Adsorption Separation Light hydrocarbons MOF

Vegetation physiological parameter setting in the Simple Biosphere model 2(SiB2) for alpine meadows in the upper reaches of Heihe river

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2015年第5期58卷 755-769页

作者： LI Yuan SUN Rui LIU shao min State Key Laboratory of Remote Sensing Science Beijing Normal University and Institute of Remote Sensing and Digital Earth CAS School of Geography Beijing Normal University Beijing Key Laboratory of Environmental Remote Sensing and City Digitalization Department of Civil Engineering Monash University

Land surface process modeling of high and cold area with vegetation cover has not yielded satisfactory results in previous applications. In this study, land surface energy budget is simulated using a land surface model for the A'rou meadow in the upper-reach area of the Heihe River Basin in the eastern Tibetan Plateau. The model performance is evaluated using the in-situ observations and remotely sensed data. Sensible and soil heat fluxes are overestimated while latent heat flux is underestimated when the default parameter setting is used. By analyzing physical and physiological processes and the sensitivities of key parameters, the inappropriate default setting of optimum growth and inhibition temperatures is identified as an important reason for the bias. The average daytime temperature during the period of fastest vegetation growth(June and July) is adopted as the optimum growth temperature, and the inhibition temperatures were adjusted using the same increment as the optimum temperature based on the temperature acclimation. These adjustments significantly reduced the biases in sensible, latent, and soil heat fluxes.

关键词： SiB2 land surface process alpine meadow Heihe River Basin Tibetan Plateau

Estimation and prediction of black carbon emissions in Beijing City

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2007年第9期52卷 1274-1281页

作者： LIU Yuan shao min State Joint Key Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences Peking UniversityBeijing 100871 China

Black carbon is a by-product of incomplete combustion of carbon containing fuels. It can alter atmos-pheric radiation property and make adverse impacts on human health. The energy consumption in Beijing City depends largely on coal burning. Recently,Beijing City has been performing the municipal energy structure adjustment as a tool for air pollution abatement,aiming at the air quality goal for the Beijing 2008 Olympic Games. Based on Beijing energy use data in 2000,combined with emission fac-tors of major sources of black carbon,the emission of black carbon in Beijing City is estimated to be 7.77 Gg. Coke,raw coal and biomass as non-commercial energy are the main contributors to municipal black carbon emissions. Based on Beijing energy planning in the year 2008,the emission of black carbon in 2008 will be 2.97 Gg if the contribution from biomass is not taken into account. Assuming that the black carbon emission from rural biomass in 2008 is the same as that in 2004,the biomass burning will be the largest emitter of black carbon to Beijing City in 2008.

关键词：北京炭黑排放估计预测空气污染物

Numerical Study on Scale Effect of Form Factor for DTMB5415, KCS,KVLCC2, and 4000TEU Container Ship

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2021年第5期35卷 767-778页

作者： WANG Zhan-zhi min shao-song PENG Fei Department of Naval Architecture and Ocean Engineering Naval University of EngineeringWuhan 430033China

Four ships,a twin-propeller naval ship,two single-propeller container ships,and a single-propeller very large crude carrier(VLCC),were studied to investigate the scale effect of the form *** viscous flow fields of the ships at different scales were solved numerically via the Reynolds-averaged Navier–Stokes method combined with the shear stress transport k–ωturbulence *** numerical method was validated through comparisons with experimental data,and numerical uncertainty analysis was carried out based on the ITTC recommended *** this basis,scale effects of the form factor were analyzed using different friction lines,and scale effects of flow fields and the mean axial wake fractions were further analyzed in *** results showed that the form factor exhibited scale effects when adopting the ITTC-1957 line,and it increased with the increase in the Reynolds *** scale effect of the form factor reduces the prediction precision of the full-scale ship *** friction line has a significant effect on the form *** form factor exhibits little dependence on the Reynolds number when using the numerical friction line or the Katsui line,which is useful for full-scale ship resistance *** the increasing Reynolds number,the boundary layer thickness becomes thinner and the axial velocity contour contracts toward the center plane,and there is nearly a linear relationship between the reciprocal of mean axial wake fraction on propeller disc and Reynolds number in logarithmic scale for the three types of ship forms.

关键词： form factor scale effect ITTC-1957 line numerical calculation flow field

Advances in micro-nano biosensing platforms for intracellular electrophysiology

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第11期24卷 1017-1026页

作者： Jiajin XUE min shao Zhigang GAO Ning HU General Surgery Department Children’s HospitalZhejiang University School of MedicineHangzhou 310052China Department of Chemistry Zhejiang UniversityHangzhou 310058China Zhejiang-Israel Joint Laboratory of Self-Assembling Functional Materials ZJU-Hangzhou Global Scientific and Technological Innovation CenterZhejiang UniversityHangzhou 311215China Physical Examination Center The Second Affiliated Hospital of Zhejiang University School of MedicineHangzhou 310052China

The establishment of a dependable electrophysiological detection platform is paramount for cardiology and neuroscience *** the past decade,devices based on micro and nanoscale sensing and control technologies have been developed to construct electrophysiological *** unique morphological advantages and novel processing methods offer the potential for high-throughput,high-fidelity electrical signal *** this review,we analyze the structure,transmembrane strategies,and electrophysiological detection methods of active/passive micro and nano sensing *** also provide an outlook on their vast potential for development in light of the opportunities and challenges facing micro and nano sensing technology,with the aim of pushing for higher-level electrophysiological platform construction to meet the needs of experimental research and clinical applications.

关键词： Intracellular electrophysiology Micro-nano biosensing platforms Cardiology and neuroscience Intracellular action potentials

RHEOLOGICAL PROPERTIES OF WHEAT GLIADINS IN AQUEOUS PROPANOL

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2013年第5期31卷 809-814页

作者： shao-min Sun 宋义虎 Qiang Zheng MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang University

Rheological properties of wheat gliadins in 50% （V/F） aqueous propanol were carried out as a function of gliadin concentration c and temperature. The solutions at 20 g L-1 to 200 g L-1 behave as Newtonian fluids with an flow activation energy of 23.5-27.3 kJ mol-1. Intrinsic viscosity [η] and Huggins constant kH are determined according to Huggins plot at c 〈 120 g L-1. The results reveal that gliadins are not spherical shaped and the molecular size tends to increase with temperature due to improved solvation.

关键词： Gliadin Solution Rheological properties Intrinsic viscosity.

Investigation of carbonyl compound sources at a rural site in the Yangtze River Delta region of China

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2015年第2期27卷 128-136页

作者： ming Wang Wentai Chen min shao Sihua Lu Limin Zeng min Hu State Joint Key Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences and EngineeringPeking University

Carbonyl compounds are important intermediates in atmospheric photochemistry, but their primary sources are still not understood well. In this work, carbonyls, hydrocarbons,and alkyl nitrates were continuously measured during November 2011 at a rural site in the Yangtze River Delta region of China. Mixing ratios of carbonyls and hydrocarbons showed large fluctuations during the entire measurement. The average level for total measured volatile organic compounds during the pollution episode from 25 th to 27 th November, 2011 was 91.6 ppb, about 7 times the value for the clean period of 7th–8th, November, 2011. To preliminarily identify toluene sources at this site, the emission ratio of toluene to benzene（T/B） during the pollution episode was determined based on photochemical ages derived from the relationship of alkyl nitrates to their parent alkanes. The calculated T/B was5.8 ppb/ppb, significantly higher than the values of 0.2–1.7 ppb/ppb for vehicular exhaust and other combustion sources, indicating the dominant influence of industrial emissions on ambient toluene. The contributions of industrial sources to ambient carbonyls were then calculated using a multiple linear regression fit model that used toluene and alkyl nitrates as respective tracers for industrial emission and secondary production. During the pollution episode, 18.5%, 69.0%, and 52.9% of measured formaldehyde, acetaldehyde, and acetone were considered to be attributable to industrial emissions. The emission ratios relative to toluene for formaldehyde, acetaldehyde, and acetone were determined to be 0.10, 0.20 and0.40 ppb/ppb, respectively. More research on industrial carbonyl emission characteristics is needed to understand carbonyl sources better.

关键词： Carbonyl compounds Source apportionment Industrial emission Yangtze River Delta