检索结果-南通市图书馆

Determination of mining-induced stresses using diametral rock core deformations

在线全文

学校读者我要写书评

暂无评论

International Journal of Coal science & Technology 2022年第6期9卷 13-24页

作者： Yizhuo Li Hani s.Mitri Department of Mining and Materials Engineering McGill UniversityMontrealCanada

Knowledge of ground stresses is crucial for ground control activities such as the design of underground openings,selec-tion of support systems,and analysis for ***,it is a known fact that far field stresses experience changes in orientation and magnitude due to the presence of geological structures and due to the excavations created by mining *** a result,in-situ stresses around drifts,ramps,and stopes in underground mines are quite different from far field or pre-mining *** purpose of this research is to develop a simple and practical methodology for determining in-situ *** relief occurs once the rock core is drilled *** relief is a function of the surrounding stress *** study uses exploration rock cores that are drilled off for the purpose of orebody definition in the underground *** method measures and analyzes the diametral core deformations in *** case studies from operating underground mines are presented for *** these case studies,rock core deformations are measured with a customized test apparatus and rock samples were prepared and tested for Young's modulus and Poisson's *** differential stress,namely the difference between the local principal stresses in the plane perpendicular to the core rock axis is *** is shown that this methodology is useful for determining the brittle shear ratio in the rock mass,which is of primary interest to ground control studies.

关键词： In-situ stresses Rock core diametral deformation strain relief Core-based stress measurement Brittle shear ratio

Numerical Examination of the Effects of Ion Thermal flow on Plasma sheath Characteristics

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 Physics Letters 2013年第8期30卷 110-113页

作者： Mansour Khoramabadi s.farhad Masoudi Department of Physics Boroujerd BranchIslamic Azad UniversityP.O.Box 518BoroujerdIran Department of Physics K.N.Toosi University of TechnologyP.O.Box 15875-4416TehranIran

The effects of ion thermal flow on the electric and hydrodynamic characteristics of a plasma sheath are examined using a multi-fluid *** comparison with cold plasma,ion pressure is modeled by a power law dependence on the ion density in warm *** pressure force on the ion depends on the ion density,ion temperature,and a nearly constant parameter called the ion polytropic *** well-known quantities for this coefficient,γi=1 and 3,are considered,corresponding to isothermal and adiabatic flows,*** numerical calculations show that increasing the ion temperature decreases the sheath thickness and increases the ion impact energy and ion saturation current at the *** ion polytropic coefficient has the same effect as the ion temperature and intensifies the ion temperature effects.

关键词： coefficient coefficient quantities

Transcontinental Translational Medicine Collaboration: A successful sinoCuban Joint B-to-B Program

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Biomedical and Environmental sciences 2013年第7期26卷 517-519页

作者： LU Kai CHEN Tao CHEN Yu George f. Gao Chinese Center for Disease Control and Prevention

Translational medicine is a comprehensive discipline that aims to convert laboratory research results into products and technology for clinical application using modern molecular biological techniques, to improve our understanding of the human body and disease and to optimize laboratory design for clinical observation and analysis for basic research. Its ultimate goal is improving holistic medicine and helping patients solve their health problems. Translational medicine includes two processes： bench to bedside and bedside to bench, known as B-to-B processes. The first B-to-B （bench to bedside） refers to the application of results of the laboratory to clinical use as a medical product or a diagnosis and treatment technology. The second B-to-B （bedside to bench） describes the process by which clinical observation and analysis provides ideas and guidance for experiment design for basic medical research. The two processes complement each other and constitute the two-way cycle of translational medicine. Translational medicine can be applied to clinical disease detection in the form of new biomarkers and can accelerate drug discovery. In recent years, with the biotechnology, increasing rapid development of outcomes of research on molecular pathogenesis can be directly applied to clinical theraDv.

关键词： Transcontinental Translational Medicine Collaboration A successful sinoCuban Joint B-to-B Program

Incidence and determinants of sudden infant death syndrome:a population-based study on 37 million births

在线全文

学校读者我要写书评

暂无评论

World Journal of Pediatrics 2015年第1期11卷 41-47页

作者： Ghaidaa f Hakeem Lisa Oddy Christina A Holcroft Haim A Abenhaim Department of Obstetrics and Gynecology Jewish General HospitalMcGill University Center for Clinical Epidemiology and Community studies Jewish General HospitalMontréalQuébecCanada

Background:The objective of our study is to measure the incidence of sudden infant death syndrome(sIDs),estimate the birth to death interval,and identify associated maternal and infant risk ***:We carried out a population-based cohort study on 37418280 births using data from the Centers for Disease Control and Prevention's"Linked Birth-Infant Death"and"fetal Death"data files from 1995 to *** statistics and cox-proportional hazard models were used to estimate the adjusted effect of maternal and newborn characteristics on the risk of ***:There were 24101 cases of sIDs identified for an overall 10-year incidence of 6.4 cases per 10000 *** the study period,the incidence decreased from 8.1 to 5.6 per 10000 and appeared to be most common among infants aged 2-4 *** factors inchuded maternal ages,black,non-Hispanic race,smoking,increasing parity,inadequate prenatal care,prematurity and growth ***:While the incidence of sIDs in the Us has declined,it currently remains the leading cause of post-neonatal mortality,highlighting an important public health *** campaigns should be targeted towards mothers at increased risk in order to raise their awareness of modifiable risk factors for sIDs such as maternal smoking and inadequate prenatal care.

关键词： incidence risk factors sudden infant death syndrome

A composite sphere assemblage model for porous oolitic rocks:Application to thermal conductivity

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2017年第1期9卷 54-61页

作者： f. Chen A. Giraud D. Grgic K. Kalo Geo Ressources Laboratory Université de Lorraine (ENSG) CNRS CREGU Vandoeuvre-lès-Nancy F-54518 France

The present work is devoted to the determination of linear effective thermal conductivity of porous rocks characterized by an assemblage of grains(oolites) coated by a matrix. Two distinct classes of pores, *** or intra oolitic pores(oolite porosity) and mesopores or inter oolitic pores(inter oolite porosity), are taken into account. The overall porosity is supposed to be connected and decomposed into oolite porosity and matrix porosity. Within the framework of Hashin composite sphere assemblage(CsA)models, a two-step homogenization method is developed. At the first homogenization step, pores are assembled into two layers by using self-consistent scheme(sCs). At the second step, the two porous layers constituting the oolites and the matrix are assembled by using generalized self-consistent scheme(GsCs) and referred to as three-phase model. Numerical results are presented for data representative of a porous oolitic limestone. It is shown that the influence of porosity on the overall thermal conductivity of such materials may be significant.

关键词： Effective thermal conductivity Three-phase model Oolitic limestone Composite sphere assemblage(CsA) model

Propagation behavior of elastic waves in one-dimensional piezoelectric/piezomagnetic phononic crystal with line defects

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica sinica 2014年第5期30卷 703-713页

作者： Y.Pang f.-Y.Jiao J.-X.Liu Department of Engineering Mechanics Shijiazhuang Tie Dao University school of Mathematics and Physics University of Science and Technology Beijing

Using a stiffness matrix method, we in- vestigate the propagation behaviors of elastic waves in one-dimensional （1D） piezoelectric/piezomagnetic （PE/PM） phononic crystals （PCs） with line defects by calculating energy reflection/transmittion coefficients of quasi-pressure and quasi-shear waves. Line defects are created by the re- placement of PE or PM constituent layer. The defect modes existing in the first gap are considered and the influences on defect modes of the material properties and volume fraction of the defect layers, the type of incident waves, the location of defect layer and the number of structural layers are discussed in detail. Numerical results indicate that defect modes are the most obvious when the defect layers are inserted in the middle of the perfect PCs; the types of incidence wave and material properties of the defect layers have important effects on the numbers, the location of frequencies and the peaks of defect modes, and the defect modes are strongly de- pendent on volume fraction of the defect layers. We hope this paper will be found useful for the design of PE/PM acoustic filters or acoustic transducer with PCs structures.

关键词： 1D phononic crystal Piezoelectric/piezomag- netic. Elastic wave Line defect stiffness matrix method

Influence of Non-Magnetic substitutional Atoms on spontaneous Moment and Curie Temperature of Ce_2Co_(17) Compounds

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2002年第4期20卷 273-277页

作者：胡社军刘正义 De Boer f R Buschow K H J faculty of Materials and Energy Guangdong University of Technology Guangzhou 510643 China

The structure and magnetic properties of Ce 2Co 17-xM x(M=Ga,Al and si) compounds for M concentrations up to x=5 were studied by means of X-ray diffraction and magnetic measurements. The experimental results show that the Curie temperatures and Co spontaneous magnetization decrease significantly with increasing the addition of non-magnetic substitutional atoms, and that si which has a minimum solid solubility in Ce 2Co 17 causes a largest reduction of Curie temperature, spontaneous magnetization and moment per Co atom compared with Ga and Al.

关键词： rare earths Ce 2Co 17 compounds Curie temperature spontaneous magnetization

Text-Independent Algorithm for source Printer Identification Based on Ensemble Learning

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2022年第10期73卷 1417-1436页

作者： Naglaa f.El Abady Mohamed Taha Hala H.Zayed Department of Computer science Faculty of Computers and Artificial IntelligenceBenha University13518Egypt school of Information Technology and Computer science(ITCs) Nile University12677Egypt

Because of the widespread availability of low-cost printers and scanners,document forgery has become extremely *** or signatures are used to protect important papers such as certificates,passports,and identification *** the origins of printed documents is helpful for criminal investigations and also for authenticating digital versions of a document in today’s *** printer identification(sPI)has become increasingly popular for identifying frauds in printed *** paper provides a proposed algorithm for identifying the source printer and categorizing the questioned document into one of the printer classes.A dataset of 1200 papers from 20 distinct(13)laser and(7)inkjet printers achieved significant identification results.A proposed algorithm based on global features such as the Histogram of Oriented Gradient(HOG)and local features such as Local Binary Pattern(LBP)descriptors has been proposed for printer *** classification,Decision Trees(DT),k-Nearest Neighbors(k-NN),Random forests,Aggregate bootstrapping(bagging),Adaptive-boosting(boosting),support Vector Machine(sVM),and mixtures of these classifiers have been *** proposed algorithm can accurately classify the questioned documents into their appropriate printer *** adaptive boosting classifier attained a 96%*** proposed algorithm is compared to four recently published algorithms that used the same dataset and gives better classification accuracy.

关键词： Document forensics source printer identification(sPI) HOG LBP principal component analysis(PCA) bagging AdaBoost

Transcriptome profile of human neuroblastoma cells in the hypomagnetic field

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

science China(Life sciences) 2014年第4期57卷 448-461,1-3页

作者： MO WeiChuan LIU Ying BARTLETT Perry f HE RongQiao Institute of Biophysics Chinese Academy of Sciences Queensland Brain Institute The University of QueenslandBrisbane

Research has shown that the hypomagnetic field(HMf)can affect embryo development,cell proliferation,learning and memory,and in vitro tubulin *** the present study,we aimed to elucidate the molecular mechanism by which the HMf exerts its effect,by comparing the transcriptome profiles of human neuroblastoma cells exposed to either the HMf or the geomagnetic field.A total of 2464 differentially expressed genes(DEGs)were identified,216 of which were up-regulated and2248 of which were down-regulated after exposure to the *** DEGs were found to be significantly clustered into several key processes,namely macromolecule localization,protein transport,RNA processing,and brain *** DEGs were verified by real-time quantitative PCR,and the expression levels of nine of these DEGs were measured every 6 *** notably,MAPK1 and CRY2,showed significant up-and down-regulation,respectively,during the first 6 h of HMf exposure,which suggests involvement of the MAPK pathway and cryptochrome in the early bio-HMf *** results provide insights into the molecular mechanisms underlying the observed biological effects of the HMf.

关键词： hypomagnetic field geomagnetic field transcriptome profile massively parallel sequencing MAPK1 CRY2