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41.
Peter M. Kekenes-Huskey Don E. Burgess Bin Sun Daniel C. Bartos Ezekiel R. Rozmus Corey L. Anderson Craig T. January Lee L. Eckhardt Brian P. Delisle 《International journal of molecular sciences》2022,23(13)
The electrocardiogram (ECG) empowered clinician scientists to measure the electrical activity of the heart noninvasively to identify arrhythmias and heart disease. Shortly after the standardization of the 12-lead ECG for the diagnosis of heart disease, several families with autosomal recessive (Jervell and Lange-Nielsen Syndrome) and dominant (Romano–Ward Syndrome) forms of long QT syndrome (LQTS) were identified. An abnormally long heart rate-corrected QT-interval was established as a biomarker for the risk of sudden cardiac death. Since then, the International LQTS Registry was established; a phenotypic scoring system to identify LQTS patients was developed; the major genes that associate with typical forms of LQTS were identified; and guidelines for the successful management of patients advanced. In this review, we discuss the molecular and cellular mechanisms for LQTS associated with missense variants in KCNQ1 (LQT1) and KCNH2 (LQT2). We move beyond the “benign” to a “pathogenic” binary classification scheme for different KCNQ1 and KCNH2 missense variants and discuss gene- and mutation-specific differences in K+ channel dysfunction, which can predispose people to distinct clinical phenotypes (e.g., concealed, pleiotropic, severe, etc.). We conclude by discussing the emerging computational structural modeling strategies that will distinguish between dysfunctional subtypes of KCNQ1 and KCNH2 variants, with the goal of realizing a layered precision medicine approach focused on individuals. 相似文献
42.
Reduction Algorithms Based on Discernibility Matrix: The Ordered Attributes Method 总被引:36,自引:2,他引:36
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1 IntroductionIn Rough Set Theory[1], Pawall has defined two sorts of infOrInion systems withoat and withdecision attributes, denoted as (U C} and (U C U D) respectthely Rere U is the forrse Of obects,Me C and D aJre the condition attribote set tal the decision attriliute set respectively Their reductsare called reduct and rel8Jtive reduct reSPecttwBy Pawha, a reduct must satisfy a indePendent conditbo, tha is, a reduct 0 / R G C, R is'independent if Vr C R, mD(R) / mD(R-- {r}) f… 相似文献
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Piston-ring and Cylinder-liner Lubrication in Internal Combustion Engines Based on Thermo-hydrodynamic 总被引:1,自引:1,他引:0
ZHANG Junhong GAO Hongge NI Guangjian State Key Laboratory of Engine Tianjin University Tianjin China Tianjin Internal Combustion Engine Research Institute China Received April revised March accepted August published electronically August 《机械工程学报(英文版)》2011,(6)
Currently the extruded effect,roughness to the lubricant shear thinning,temperature changes and other factors or some combination of a single factor mainly considered in the lubrication study of piston ring-cylinder.In the study of the energy equation,the oil viscosity-temperature properties,adsorption layer characteristics are usually not considered.So the theoretical research is different from the actual situation of engineering.The lubrication of piston ring-cylinder liner system in internal combustion(I... 相似文献
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LIANG Xingyu WANG Yuesen SHU Gequn WEI Haiqiao DONG Lihui MEI Yifan State Key Laboratory of Engines Tianjin University Tianjin China Oil Material Research Institute PLA Genera Logistics Department Beijing China Received February revised March accepted March published electronically November 《机械工程学报(英文版)》2011,(6):1022-1027
Violent axial vibration of a vehicle engine crankshaft might lead to multiple defects to the engine.Much research on mechanism and control measures has been done on engines,such as using the dynamic stiffness matrix method,rayleigh differential method,and system matrix method.But the source of axial vibration has not been identified clearly because there are many excitation factors for the axial vibration of a crankshaft,such as coupled torsional-axial vibration and coupled bending-axial vibration,etc.In order to improve the calculation reliability and identify the excitation source of axial vibration of in vehicle engine crankshafts,this paper presents a method to identify the axial vibration excitation source of crankshafts for high speed diesel engines based on an auto-regressive and moving average(ARMA) model.Through determining initial moving average variables and measuring axial /bending/torsional vibrations of a crankshaft at the free-end of a 4-cylinder diesel engine,autoregressive spectrum analysis is applied to the measured vibration signal.The results show that the axial vibration of the crankshaft is mainly excited by coupled bending vibration at high speed.But at low speed,the axial vibration in some frequencies is excited primarily by torsional excitation.Through investigation of axial vibration source of engine crankshafts,calculation accuracy of vibration can be improved significantly. 相似文献
45.
ZHENG Songlin XU Honghui FENG Jinzhi ZHENG Zuanxi WANG Youtao LU Leilei College of Mechanical Engineering University of Shanghai for Science Technology Shanghai China College of Automotive Engineering Tongji University Shanghai China Received April revised November accepted June published electronically June 《机械工程学报(英文版)》2011,(6):1111-1115
There are two kinds of internationally recognized approaches in terms of lightweight design.One is based on fatigue accumulated damage theory to achieve better reliability by optimal structural design;another is to use high performance lightweight materials.The former method takes very few considerations on the structural strengthening effects caused by the massive small loads in service.In order to ensure safety,the design is usually conservative,but the strength potential of the component is not fully exerted.In the latter method,cost is the biggest obstacle to lightweight materials in automotive applications.For the purpose of light weighting design on a fuel cell vehicle,the new design method is applied on drive shafts.The method is based on the low amplitude load strengthening characteristics of the material,and allows the stress,corresponding to test load,to enter into the strengthened range of the material.Under this condition,the light weighting design should assure that the reliability of the shaft is not impaired,even maximizes the strength potential of machine part in order to achieve the weight reduction and eventually to reduce the cost.At last,the feasibility of the design is verified by means of strength analysis and modal analysis based on the CAD model of light weighted shaft.The design applies to the load case of half shaft in independent axle,also provides technological reference for the structural lightweight design of vehicles and other machineries. 相似文献
46.
January Gnitecki Zahra M K Moussavi 《IEEE engineering in medicine and biology magazine》2007,26(1):20-29
This study reviews the adaptive methods of canceling heart sounds from lung sounds that have been investigated over approximately 20 years. Filtering techniques are categorized as linear adaptive filters and filters employing time-frequency based methods. Several filtering schemes are outlined within these two categories. Methods of heart sound localization are indicated in conjunction with the studies of heart-sound cancellation. Details such as digitization parameters, the location of heart and lung sound recordings, and the number of subjects used in each study. Since a primary objective of respiratory sound research is bring about improvements to monitoring and diagnosis of respiratory disease, the potential usefulness of any method for filtering heart sounds from lung sounds rests on its ability to perform in a clinical setting 相似文献
47.
在前文的研究基础上,本文研究了过渡族元素在Ti-Al-Sc,Ti-Al-V,Ti-Al-Nb和Ti-Al-Mo四个三元合金系中Ti,X相形成中的行为。 实验结果表明:在含有过渡族元素Sc,V,Nb和Mo的Ti-Al固溶体中,Ti_3X相的形成仍然遵守电子浓度规律,且过渡族元素的价电子数是由它们的d能带结构决定的。对周期表中位于Ti左侧的Sc,N_(sc)=2(s~2);对周期表中位于Ti右侧的V,Nb和Mo,N_v=3(d~3),N_(Nb)=4(d~4),和N_(Mo)=5(d~5)。另外,实验结果还表明:合金中添加任何一种过渡族元素都不可能对Ti,X相的形成有抑制作用。 相似文献
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CHEN Huawei WANG Aimin NING Ruxin SHAO Canxia Digital Design Manufacturing Laboratory Beijing Institute of Technology Beijing China Received February revised February accepted February published electronically February 《机械工程学报(英文版)》2011,(6):1035-1044
With sustaining change of production mode,layout planning is no longer a thing built once for all.Cellular layout(CL) is becoming a hotspot in the research field of manufacturing system layout.Traditional researches on layout planning are mainly concentrating on aspects of layout arithmetic,style and evaluation,etc.Relatively seldom efforts are paid to CL and its specific problems as cell formation(CF),equipment sharing and CL analysis.Through problem analyzing of layout in cellular manufacturing system(CMS),research approach of cell formation,interactive layout and layout analysis threaded with process interconnection relationship(PIR) is proposed.Typical key technologies in CL like CF technology based on similarity analysis of part processes,interactive visual layout technology,layout evaluation technology founded on PIR analysis and algorithm of cell equipment sharing are put forward.Against the background of one enterprise which encounters problems of low utility of key equipments and disperse material logistic,an example of four-cell layout is given.The CL adjustment and analysis results show that equipment with high level of sharing degree should be disposed around the boundary of its main cell,and be near to other sharing cells as possible;process route should be centralized by all means,so equipment adjustment is to be implemented along direction that route intersection can be decreased;giving consideration to the existence of discrete cell,logistic route and its density should be centralized to cells formed.The proposed research can help improve equipment utility and material logistic efficiency of CL,and can be popularized to other application availably. 相似文献
50.
HE Bin XIAO Xinbiao JIN Xuesong FANG Jianying State Key Laboratory of Traction Power Southwest Jiaotong University Chengdu China Knorr-Bremse Systems for Rail Vehicles Co.Ltd Suzhou China Received February revised March accepted March published electronically November 《机械工程学报(英文版)》2011,(6):1056-1067
The existing researches on the damping wheel mainly focus on investigating the influence of damping structure change on the vibro-acoustic control.The changes include the geometric size of the damping structure,the damping material parameters,and the placement,and so on.In order to further understand the mechanism in reducing the acoustic radiation of railway wheel with layer damping treatment,in this paper,the wheel is simply modified by a full-sized circular plate.The circle plate side has stuck circumference constrained damping ridges and radial constrained damping ridges on it.Based on a hybrid finite element method-boundary element method(FEM-BEM),the paper develops a vibro-acoustic radiation model for such a distributed constrained damping structure.The vibration and acoustic radiation of the circular plate is analyzed.In the analysis,the dynamic response of the system is obtained by using the 3D finite model superposition method.The obtained vibration response is used as the initial boundary condition in solving Helmholtz boundary integral equation for the sound radiation analysis.In the procedure,firstly,the modal analysis of the circular plate is performed to get the distribution of the system modal strain energy.Secondly,the vibro-acoustic radiation characteristics of the plate with different kinds of circumference damping ridges and radial damping ridges are compared in order to try to find the best effective damping ridge structure.Thirdly,using the distribution of the plate modal strain energy investigates the effect of the ridge distribution locations on the circular plate on its vibro-acoustic radiation.The calculation and analysis research results show that,the sticking circumference and radial damping ridges on the plate can control the vibro-acoustic radiation of the plate effectively in different frequency range.The distribution of the constrained damping ridge has an effect on reduction in vibro-acoustic radiation of the circular plate.The present research is very useful in the design of railway wheel with low noise level. 相似文献