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Assessing the Impact of Using Different Land Cover Classification in Regional Modeling Studies for the Manaus Area,Brazil
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作者 Sameh Adib Abou Rafee Ana Beatriz Kawashima +3 位作者 Marcos Vinícius Bueno de Morais Viviana Urbina Leila Droprinchinski Martins Jorge Alberto Martins 《Journal of Geoscience and Environment Protection》 2015年第6期77-82,共6页
Land cover classification is one of the main components of the modern weather research and forecasting models, which can influence the meteorological variable, and in turn the concentration of air pollutants. In this ... Land cover classification is one of the main components of the modern weather research and forecasting models, which can influence the meteorological variable, and in turn the concentration of air pollutants. In this study the impact of using two traditional land use classifications, the United States Geological Survey (USGS) and the Moderate-resolution Imaging Spectroradiometer (MODIS), were evaluated. The Weather Research and Forecasting model (WRF, version 3.2.1) was run for the period 18 - 22 August, 2014 (dry season) at a grid spacing of 3 km centered on the city of Manaus. The comparison between simulated and ground-based observed data revealed significant differences in the meteorological fields, for instance, the temperature. Compared to USGS, MODIS classification showed better skill in representing observed temperature for urban areas of Manaus, while the two files showed similar results for nearby areas. The analysis of the files suggests that the better quality of the simulations favorable to the MODIS file is straightly related to its better representation of urban class of land use, which is observed to be not adequately represented by USGS. 展开更多
关键词 Land Use and Land Cover Classification Regional modeling studies Urban Air Quality
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A CLOUD-RESOLVING MODELING STUDY OF SURFACE RAINFALL PROCESSES ASSOCIATED WITH LANDFALLING TYPHOON KAEMI(2006) 被引量:8
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作者 崔晓鹏 许凤雯 《Journal of Tropical Meteorology》 SCIE 2009年第2期181-191,共11页
The detailed surface rainfall processes associated with landfalling typhoon Kaemi(2006) are investigated based on hourly data from a two-dimensional cloud-resolving model simulation. The model is integrated for 6 da... The detailed surface rainfall processes associated with landfalling typhoon Kaemi(2006) are investigated based on hourly data from a two-dimensional cloud-resolving model simulation. The model is integrated for 6 days with imposed large-scale vertical velocity, zonal wind, horizontal temperature and vapor advection from National Center for Environmental Prediction (NCEP) / Global Data Assimilation System (GDAS) data. The simulation data are validated with observations in terms of surface rain rate. The Root-Mean-Squared (RMS) difference in surface rain rate between the simulation and the gauge observations is 0.660 mm h^-1, which is smaller than the standard deviations of both the simulated rain rate (0.753 mm h^-1) and the observed rain rate (0.833 mm h^-1). The simulation data are then used to study the physical causes associated with the detailed surface rainfall processes during the landfall. The results show that time averaged and model domain-mean Ps mainly comes from large-scale convergence (QWVF) and local vapor loss (positive QWVT). Large underestimation (about 15%) of Ps will occur if QWVT and QCM (cloud source/sink) are not considered as contributors to Ps ,QWVF accounts for the variation of P during most of the integration time, while it is not always a contributor to Ps,Sometimes surface rainfall could occur when divergence is dominant with local vapor loss to be a contributor to Ps - Surface rainfall is a result ofmulti-timescale interactions. QWVE possesses the longest time scale and the lowest frequeney the second and QCM of variation with time and may exert impact on P on longer time scales. QWVF possesses longest time scale and lowest frequency and can explain most of the variation of Ps. QWVT possess shorter time scales and higher frequencies, which can explain more detailed variations in Ps. Partitioning analysis shows that stratiform rainfall is dominant from the morning of 26 July till the late night of 27 July. After that, convective rainfall dominates till about 1000 LST 28 July. Before 28 July, the variations of QWVT in rainfall-free regions contribute less to that of the domain-mean QWVT while after that they contribute much, which is consistent to the corresponding variations in their fractional coverage. The variations of QWVF in rainfall regions are the main contributors to that of the domain-mean QWVF, then the main contributors to the surface rain rate before the afternoon of 28 July. 展开更多
关键词 surface rainfall processes landfalling typhoon cloud-resolving modeling study
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Snow and sea ice thermodynamics in the Arctic:Model validation and sensitivity study against SHEBA data 被引量:6
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作者 Cheng Bin Timo Vihma +2 位作者 Zhang Zhanhai Li Zhijun Wu Huiding 《Chinese Journal of Polar Science》 2008年第2期108-122,共15页
Evolution of the Arctic sea ice and its snow cover during the SHEBA year were simulated by applying a high-resolution thermodynamic snow/ice model (HIGHTSI). Attention was paid to the impact of albedo on snow and se... Evolution of the Arctic sea ice and its snow cover during the SHEBA year were simulated by applying a high-resolution thermodynamic snow/ice model (HIGHTSI). Attention was paid to the impact of albedo on snow and sea ice mass balance, effect of snow on total ice mass balance, and the model vertical resolution. The SHEBA annual simulation was made applying the best possible external forcing data set created by the Sea Ice Model Intercomparison Project. The HIGHTSI control run reasonably reproduced the observed snow and ice thickness. A number of albedo schemes were incorporated into HIGHTSI to study the feedback processes between the albedo and snow and ice thickness. The snow thickness turned out to be an essential variable in the albedo parameterization. Albedo schemes dependent on the surface temperature were liable to excessive positive feedback effects generated by errors in the modelled surface temperature. The superimposed ice formation should be taken into account for the annual Arctic sea ice mass balance. 展开更多
关键词 ARCTIC sea ice model validation and sensitivity study SHEBA data.
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Verification of a laboratory-based dilation model for in situ conditions using continuum models 被引量:6
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作者 G.Walton M.S.Diederichs +1 位作者 L.R.Alejano J.Arzúa 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2014年第6期522-534,共13页
With respect to constitutive models for continuum modeling applications, the post-yield domain remainsthe area of greatest uncertainty. Recent studies based on laboratory testing have led to thedevelopment of a number... With respect to constitutive models for continuum modeling applications, the post-yield domain remainsthe area of greatest uncertainty. Recent studies based on laboratory testing have led to thedevelopment of a number of models for brittle rock dilation, which account for both the plastic shearstrain and confining stress dependencies of this phenomenon. Although these models are useful inproviding an improved understanding of how dilatancy evolves during a compression test, there hasbeen relatively little work performed examining their validity for modeling brittle rock yield in situ. Inthis study, different constitutive models for rock dilation are reviewed and then tested, in the context of anumber of case studies, using a continuum finite-difference approach (FLAC). The uncertainty associatedwith the modeling of brittle fracture localization is addressed, and the overall ability of mobilizeddilation models to replicate in situ deformation measurements and yield patterns is evaluated. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved. 展开更多
关键词 Dilation Continuum models Case studies Brittle rock
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Modeling study on the flow patterns of gas–liquid flow for fast decarburization during the RH process 被引量:2
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作者 Yi-hong Li Yan-ping Bao +2 位作者 Rui Wang Li-feng Ma Jian-sheng Liu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2018年第2期153-163,共11页
A water model and a high-speed video camera were utilized in the 300-t RH equipment to study the effect of steel flow patterns in a vacuum chamber on fast decarburization and a superior flow-pattern map was obtained d... A water model and a high-speed video camera were utilized in the 300-t RH equipment to study the effect of steel flow patterns in a vacuum chamber on fast decarburization and a superior flow-pattern map was obtained during the practical RH process. There are three flow patterns with different bubbling characteristics and steel surface states in the vacuum chamber: boiling pattern(BP), transition pattern(TP), and wave pattern(WP). The effect of the liquid-steel level and the residence time of the steel in the chamber on flow patterns and decarburization reaction were investigated, respectively. The liquid-steel level significantly affected the flow-pattern transition from BP to WP, and the residence time and reaction area were crucial to evaluate the whole decarburization process rather than the circulation flow rate and mixing time. A superior flow-pattern map during the practical RH process showed that the steel flow pattern changed from BP to TP quickly, and then remained as TP until the end of decarburization. 展开更多
关键词 modeling study flow pattern vacuum chamber residence time decarburization RH process
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A Systematic Review of Animal and Clinical Studies on the Use of Scaffolds for Urethral Repair 被引量:3
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作者 祁娜 李文娇 田虹 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2016年第1期111-117,共7页
Replacing urethral tissue with functional scaffolds has been one of the challenging problems in the field of urethra reconstruction or repair over the last several decades. Various scaffold materials have been used in... Replacing urethral tissue with functional scaffolds has been one of the challenging problems in the field of urethra reconstruction or repair over the last several decades. Various scaffold materials have been used in animal studies, but clinical studies on use of scaffolds for urethral repair are scarce. The aim of this study was to review recent animal and clinical studies on the use of different scaffolds for urethral repair, and to evaluate these scaffolds based on the evidence from these studies. Pub Med and OVID databases were searched to identify relevant studies, in conjunction with further manual search. Studies that met the inclusion criteria were systematically evaluated. Of 555 identified studies, 38 were included for analysis. It was found that in both animal and clinical studies, scaffolds seeded with cells were used for repair of large segmental defects of the urethra, such as in tubular urethroplasty. When the defect area was small, cell-free scaffolds were more likely to be applied. A lot of pre-clinical and limited clinical evidence showed that natural or artificial materials could be used as scaffolds for urethral repair. Urinary tissue engineering is still in the immature stage, and the safety, efficacy, cost-effectiveness of the scaffolds are needed for further study. 展开更多
关键词 material/scaffold urethral repair tissue engineering/regenerative medicine animal models clinical studies
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An Application of the Modified Shear Lag Model to Study the Influence of Thermal Residual Stresses on the Stiffness and Yield Strength of Short Fiber Reinforced Metal Matrix Composites 被引量:1
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作者 Zhonghao JIANG and Jianshe LIAN(Dept. of Materials Science and Engineering, Jilin University of Technology, Changchun 130025, China)Shangli DONG and Dezhuang YANG(School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1999年第3期213-221,共9页
The modified shear lag model proposed recently was applied to calculate thermal residual stresses and subsequent stress distributions under tensile and compressive loadings. The expressions for the elastic moduli and ... The modified shear lag model proposed recently was applied to calculate thermal residual stresses and subsequent stress distributions under tensile and compressive loadings. The expressions for the elastic moduli and the yield strengths under tensile and compressive loadings were derived which take account of thermal residual stresses. The asymmetries in the elastic modulus and the yield strength were interpreted using the derived expressions and the obtained results of the stress calculations. The model predictions have exhibited good agreements with the experimental results and also with the other theoretical predictions 展开更多
关键词 ab Figure An Application of the Modified Shear Lag model to Study the Influence of Thermal Residual Stresses on the Stiffness and Yield Strength of Short Fiber Reinforced Metal Matrix Composites
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Observations and Modeling of Incoming Longwave Radiation to Snow Beneath Forest Canopies in the West Tianshan Mountains, China 被引量:3
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作者 LU Heng WEI Wen-shou +2 位作者 LIU Ming-zhe HAN Xi HONG Wen 《Journal of Mountain Science》 SCIE CSCD 2014年第5期1138-1153,共16页
Forest canopy reduces shortwave radiation and increases the incoming longwave radiation to snowpacks beneath forest canopies. Furthermore, the effect of forest canopy may be changed by complex topography. In this pape... Forest canopy reduces shortwave radiation and increases the incoming longwave radiation to snowpacks beneath forest canopies. Furthermore, the effect of forest canopy may be changed by complex topography. In this paper, we measured and simulated the incoming longwave radiation to snow beneath forest at different canopy openness in the west Tianshan Mountains, China(43°16'N, 84°24'E) during spring 2013. A sensitivity study was conducted to explore the way that terrain influenced the incoming longwave radiation to snow beneath forest canopies. In the simulation model, measurement datasets, including air temperature, incoming shortwave radiation above canopy, and longwave radiation enhanced by adjacent terrain, were applied to calculate the incoming longwave radiation to snow beneath forest canopy. The simulation results were consistent with the measurements on hourly scale and daily scale. The effect of longwave radiation enhanced by terrain was important than that of shortwave radiation above forest canopy with different openness except the 20% canopy openness. The longwave radiation enhanced due to adjacent terrain increases with the slope increase and temperature rise. When air temperature(or slope) is relatively low, thelongwave radiation enhanced by adjacent terrain is not sensitive to slope(or air temperature), but the sensitivity increases with the decrease of snow cover area on sunny slope. The effect of longwave radiation is especially sensitive when the snow cover on sunny slope melts completely. The effect of incoming shortwave radiation reflected by adjacent terrain on incoming longwave radiation to snow beneath forest canopies is more slight than that of the enhanced longwave radiation. 展开更多
关键词 Incoming longwave radiation Snow beneath forest canopy Simulation model Complex topography Sensitivity study
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A GRADIENT ANALYSIS & MODELING OF THE NECT FOR GLOBAL CHANGE STUDY 被引量:6
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作者 Zhang Xinshi et al.(Laboratory of Quantitative Vegetation Ecology, Institute of Botany, CAS) 《Bulletin of the Chinese Academy of Sciences》 1998年第1期15-21,共7页
The North East China Transect (NECT) is an exemplary region of landmass running along the line of 43°30′ North Latitude and caught between 112° and 130°30′ East Longtitude, and is being sampled by the... The North East China Transect (NECT) is an exemplary region of landmass running along the line of 43°30′ North Latitude and caught between 112° and 130°30′ East Longtitude, and is being sampled by the International Geosphere-Biosphere Program (IGBP) for today’s study on global change. So far, it has already been listed in the first set of IGBP-sponsored transects, becoming a key theatre and "hot spot" for probing terrestrial ecosystems. In terms of biota, the nearly 1,600-kilometre-long tract is located in a mid-latitude zone, featuring a vegetational transition from a temperate timberland of evergreen coniferous forests and broadleaved deciduous forests to a mild-temperate steppe. According to the norms of biome types, it consists of three subzones: meadow steppe, typical steppe and desert steppe in a continuous east-to-west spatial sequence. There are four ecological stations supported by a great number of permanent samples, long-term plots and an enormous build-up of experimental data along 展开更多
关键词 NECT A GRADIENT ANALYSIS modelING OF THE NECT FOR GLOBAL CHANGE STUDY GCTE
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Cold-modeling study of a circulating fluidized bed reactor for flue gas desulfurization (FGD)
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作者 Qian, Feng Liu, Tong-Guang Zhang, Zhen-Fang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2000年第2期88-94,共7页
Short residence time of the sorbent in the gas stream and formation of a dense layer of reaction product surrounding its surface influence the sulfur removal efficiency. A practical means of improving the process perf... Short residence time of the sorbent in the gas stream and formation of a dense layer of reaction product surrounding its surface influence the sulfur removal efficiency. A practical means of improving the process performance is to employ fluidized bed reaction in replacement of entrained bed reaction on normally used in cool side desulfurizaiton. This paper describes cold modeling study of a circulating fluidized bed reactor. Several aspects of the problem are discussed: fluidization behavior of CaO, attrition of the sorbent and solids entrainment from the fluidized bed. Mechanisms and key controlling parameters are identified, and an integral model based on rate of attrition and mass balance is developed for predicting steady state mass flows and particle size distributions of the system. A process flow scheme is finally presented for conducting desulfurization tests in the second stage of the study. 展开更多
关键词 circulating fluidized bed reactor flue gas desulfurization cold modeling study CLC number: X701 Document code: A
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A Model Comparison Study of Fragment Production in 140 A MeV 58,64Ni+9Be Reactions
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作者 马春旺 张艳丽 +1 位作者 王闪闪 乔春源 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第7期29-33,共5页
The cross sections of fragments produced in the 140 A MeV58,64Ni+9 Be projectile fragmentation reactions are calculated by using the antisymmetrized molecular dynamics (AMD) model, the modified statistical abrasion... The cross sections of fragments produced in the 140 A MeV58,64Ni+9 Be projectile fragmentation reactions are calculated by using the antisymmetrized molecular dynamics (AMD) model, the modified statistical abrasion- ablation (SAA) model, and the empirical EPAX2/EPAX3 formulae. The Gogny-gO interaction is taken as the effective nucleon-nucleon interaction in the AMD calculation, and the decays of fragments obtained from the AMD results are calculated by using the GEMINI code. The calculated cross sections of fragments are compared. 展开更多
关键词 BE A model Comparison Study of Fragment Production in 140 A MeV REACTIONS AMD NI
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New models to study vulvodynia: hyperinnervation and nociceptor sensitization in the female genital tract
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作者 Christine M.Barry Kalyani K.Huilgol Rainer V.Haberberger 《Neural Regeneration Research》 SCIE CAS CSCD 2018年第12期2096-2097,共2页
Vulvodynia is a prevalent form of chronic pain, most com- monly affecting the vaginal vestibule (vestibulodynia) (Pukall et al., 2016). Women with vulvodynia describe intense pain in response to light touch of the... Vulvodynia is a prevalent form of chronic pain, most com- monly affecting the vaginal vestibule (vestibulodynia) (Pukall et al., 2016). Women with vulvodynia describe intense pain in response to light touch of the affected region, such that sexual function and other activities can be severely limited. Medical costs associated with vulvodynia are high, exceeding $21 billion annually in the United States (Xie et al., 2012). The high level of direct medical costs has been linked to high treatment failure rates. Many women with the disorder consult multiple practitioners and undergo multiple courses of treatment with limited benefit. 展开更多
关键词 New models to study vulvodynia hyperinnervation and nociceptor sensitization in the female genital tract CFA
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NUMERICAL INVESTIGATION OF THREE-DIMENSIONAL VISCOUS INCOMPRESSIBLE FLOWS IN DIVERGENT CURVED CHANNELS AND TURBULENT MODEL STUDY
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作者 焦德勇 杨弘炜 +2 位作者 赵志君 苏杰先 冯国泰 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1989年第7期639-646,共8页
In order to make the numerical calculation of viscous flows more convenient for the flows in channel with complicated profile governing equations expressed in the arbitrary curvilinear coordinates were derived by mean... In order to make the numerical calculation of viscous flows more convenient for the flows in channel with complicated profile governing equations expressed in the arbitrary curvilinear coordinates were derived by means of Favre density-weighted averaged method, and a turbulent model with effect of curvature modification was also derived. The numerical calculation of laminar and turbulent flown in divergent curved channels was carried out by means of parabolizeil computation method. The calculating results were used to analyze and investigate the aerodynamic performance of talor cascades in compressors preliminarily. 展开更多
关键词 NUMERICAL INVESTIGATION OF THREE-DIMENSIONAL VISCOUS INCOMPRESSIBLE FLOWS IN DIVERGENT CURVED CHANNELS AND TURBULENT model STUDY
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Suggestion of global model for carob batch fermentation to produce bioethanol
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作者 Bilel Hadrich Nabil Kechaou 《Journal of Chemistry and Chemical Engineering》 2009年第8期44-49,63,共7页
Modelling of carob batch fermentation is established basing on mass transfer balances. The modelling treats the reaction kinetics of substrate (S), the micro-organisms (X) and the ethanol (E). Nine models are ta... Modelling of carob batch fermentation is established basing on mass transfer balances. The modelling treats the reaction kinetics of substrate (S), the micro-organisms (X) and the ethanol (E). Nine models are taken from the literature to describe specific organism growth rate and specific ethanol development rate. These models treat all types of fermentation. The Phisalapbong et al. model and the Ghose and Tyagi model show the best fit of the experimental data. This affirms that the batch fermentation of carob is conducted with substrate and/or ethanol inhibition. Some simulations and relationships (X = f(S), E = f(S)) are obtained from the Phisalaphong et al. model. Those simulations show a lot of important and useful results of carob batch fermentation process. 展开更多
关键词 kinetics and mechanisms of reactions mathematical modelling modelling and simulation studies
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A STUDY ON MECHANICAL MODEL OF THE HELICOPTER "GROUND RESONANCE
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作者 Gu Zhong-quan Nanjing Aeronautical Institute 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 1991年第4期354-360,共7页
The key problem to the calculation and optimization design of the helicopter 'Ground Resonance' is to correctly build up a mechanical model. In the past, the literature was only concerned with the lag modes of... The key problem to the calculation and optimization design of the helicopter 'Ground Resonance' is to correctly build up a mechanical model. In the past, the literature was only concerned with the lag modes of the rotor blade and the flap modes were neglected. But such approaches should be reconsidered now. In order to study the influences of rotating multiblades rotor on the degrees of freedom and also the flap ''Ground Resonance' of a helicopter, it is necessary to consider not only the lag degrees of freedom but also the flap degrees of freedom. Using Lagrangian equation a dynamical equation of the space model for helicopter 'Ground Resonance'is deduced for the first time. Some computation results show that the mechanical model including both lag DOF and flap DOF is more reasonable. 展开更多
关键词 GROUND RESONANCE A STUDY ON MECHANICAL model OF THE HELICOPTER
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Empirical Study of "Double Threshold" Modified Model on New Product Diffusion
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作者 LIU Dan SHENG Qiran XIN Zhanhong CAO Jiantong 《China Communications》 SCIE CSCD 2014年第12期44-53,共10页
The innovations actually diffuse among social network nowadays.Individual heterogeneity,interactions between individuals and network topology influence a lot.We established a "double threshold" modified mode... The innovations actually diffuse among social network nowadays.Individual heterogeneity,interactions between individuals and network topology influence a lot.We established a "double threshold" modified model and took the number of neighbors,neighbors' adoption and the cost-benefit parameters as crucial influencing factors.The diffusion of DaLingTong(CDMA450)products in MeiShan city of SiChuan province during 2004 to 2007 has been used to verity the model on Matlab.The validation results fit the actual diffusion pattern of DaLingTong(CDMA450) products very well.The results indicate that there exists a "tipping point(threshold)" in the process of innovation diffusion.If the initial adoption quantity is larger than the tipping point,then the product will spread to a large portion of people,otherwise is will collapse to zero.The model can effectively predict the diffusion of new products,and can influence the diffusion process by changing the value of the parameters. 展开更多
关键词 innovation diffusion threshold innovation model empirical study social network
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Development of a comprehensive finite element cervical spine model for studying neck injury of pilot
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作者 Lizhen Wang1,2,Qi Zhang2,Yubo Fan2,Ming Zhang1(1 Dept.of Health Technology and Informatics,The Hong Kong Polytechnic University,Hong Kong,China 2 School of Biological Science and Medical Engineering,Beihang University,Beijing,China) 《医用生物力学》 EI CAS CSCD 2009年第S1期103-104,共2页
Introduction-The cervical spine is subjected to injury frequently,especially among pilots who are usually on the condition of high acceleration.Injuries of the cervical spine will be potential risk of damage to the sp... Introduction-The cervical spine is subjected to injury frequently,especially among pilots who are usually on the condition of high acceleration.Injuries of the cervical spine will be potential risk of damage to the spinal cord,which could be result in life threatening 展开更多
关键词 Development of a comprehensive finite element cervical spine model for studying neck injury of pilot
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Laboratory Models for the Study of the Peri-implantation Period
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作者 STANLEY R.GLASSER 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 1991年第1期48-55,共8页
The greatest risks to mammalian pregnancy occur during the peri-implantation period (passage through the uterotubal junction, blastulation, zona shedding, embryonic signaling and recognition, blastocyst attachment, po... The greatest risks to mammalian pregnancy occur during the peri-implantation period (passage through the uterotubal junction, blastulation, zona shedding, embryonic signaling and recognition, blastocyst attachment, postattachment events initiating placentation). Conventional markers and screening methods do not provide the means to clarify the relationship between exposure of a reproductively competent woman to a xenobiotic compound and the specific error in the functional expression of an embryogenetic process identified by impairment or deletion of that process. Laboratory models which provide the flexibility of in vitro culture methods and allow integration of cellular and molecular techniques have identified cell-specific, stage-specific markers that could focus on the mechanism of xenobiotic action. In vitro models have been used to define postattachment trophoblast cell differentiation. Trophoblast specific peptide hormones prove to be valid markers of established pregnancy. They provide no assessment of the risk to the embryo during the peri-implantation period. The relationship between developmental time of exposure and risk is discussed in terms of trophoblast differentiation. 展开更多
关键词 Laboratory models for the Study of the Peri-implantation Period
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Evaluation of the Accuracy of Digital Models Obtained Using Intraoral and Extraoral Scanners versus Gold Standard Plaster Model (Diagnostic Accuracy Study)
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作者 Mohammed Amr Labib Amr Ragab El-Beialy Khaled Hazem Attia 《Open Journal of Medical Imaging》 2020年第3期151-163,共13页
<b>Introduction:</b> Digital models showed promising results for orthodontic diagnosis and treatment planning. Digital models can be obtained from alginate impressions as well as direct intra-oral scanners... <b>Introduction:</b> Digital models showed promising results for orthodontic diagnosis and treatment planning. Digital models can be obtained from alginate impressions as well as direct intra-oral scanners. Studies assessing the accuracy of digital models have shown digital models to be valid, clinically acceptable, and more quickly obtainable. With the advent of new scanners with better scanning technology researches are necessary to evaluate their accuracy and reliability. <b>Aim of Study:</b> To evaluate the diagnostic accuracy of 3D digital models obtained through intraoral and extraoral scanning modalities to the reference gold standard plaster model. <b>Material & Methods:</b> Twenty-four adult male and female subjects were randomly selected for this study. The intraoral scanners evaluated in this study were Sirona (CEREC Omnicam) and 3 shape (TRIOS 3), while the laboratory scanners used were Sirona (inEos X5), and 3 shape (D850). Intra-oral scanning of the subjects and extra-oral scanning of their alginate impressions, plaster models of the alginate impression, rubber base impression, and plaster model of their rubber base impression were done. Linear dental measurements included intermolar width, interpremolar width, intercanine width, mesiodistal width of the 1<sup>st</sup> permanent molar, 1<sup>st</sup> premolar, canine and central incisor and arch width. All data were collected, tabulated and subjected to statistical analysis. <b>Results:</b> Small differences between the plaster and digital models were observed. Intra-observer reliability analysis for 14 out of the 16 measurements showed that all variables exhibited good to excellent reliability. <b>Conclusions: </b>There was no difference between the digitization using the intraoral scanner or the laboratory scanner. The most accurate digitization technique was the 3 Shape laboratory scanner of the cast of the alginate impression. The inEos X5 showed the highest error of digitization of the alginate and rubber base impressions. 展开更多
关键词 Study models Digital models ORTHODONTICS Intra-Oral Scanners Impression Scanner
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Dynamical Study of a Constant Viscous Dark Energy Model in Classical and Loop Quantum Cosmology
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作者 Sara Benchikh Noureddine Mebarki Dalel Aberkane 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第5期144-148,共5页
Dynamical behaviors and stability properties of a flat space Friedmann-Robertson-Walker universe filled with pressureless dark matter and viscous dark energy are studied in the context of standard classical and loop q... Dynamical behaviors and stability properties of a flat space Friedmann-Robertson-Walker universe filled with pressureless dark matter and viscous dark energy are studied in the context of standard classical and loop quantum cosmology. Assuming that the dark energy has a constant bulk viscosity, it is found that the bulk viscosity effects influence only the quintessence model case leading to the existence of a viscous late time attractor solution of de- Sitter type, whereas the quantum geometry effects influence the phantom model case where the big rip singularity is removed. Moreover, our results of the Hubble parameter as a function of the redshift are in good agreement with the more recent data. 展开更多
关键词 of on in Dynamical Study of a Constant Viscous Dark Energy model in Classical and Loop Quantum Cosmology is that for been FRW
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