检索结果-南通市图书馆

Post Locoregional Therapy Treatment Imaging in Hepatocellular Carcinoma Patients:A Literature-based Review

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 Clinical and Translational Hepatology 2018年第2期6卷 189-197页

作者： Shamar Young Andrew j.Taylor Tina Sanghvi Department of Radiology University of MinnesotaMinneapolisMNUSA

Imaging plays a crucial role in the diagnosis of hepatocellular carcinoma(HCC)as well as in determining treatment efficacy,or complications,following *** other cancers,HCC is most commonly treated by locoregional therapies(LRTs)such as thermal ablation,transarterial chemoembolization,and transarterial *** treatments can lead to changes on imaging that make determination of residual/recurrent disease *** literature-based review dis-cusses the expected postimaging findings following LRT.

关键词： Hepatocellular carcinoma(HCC) Transarterial chemoembolization(TACE) Thermal ablation Transarterial radioembolization(TARE) Magnetic resonance imaging(MRI)

Geant4 applications for modeling molecular transport in complex vacuum geometries

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International journal of Modeling, Simulation, and Scientific Computing 2014年第2期5卷 53-64页

作者： jack Singal j.Brian Langton Rafe Schindler Department of Physics University of Richmond Gottwald Center for the Sciences 28 Westhampton DriveRichmondVA 23173 Kavli Institute for Particle Astrophysics and Cosmology SLAC National Accelerator Laboratory and Stanford University Menlo Park CA 94025

We discuss a novel use of the Geant4 simulation toolkit to model molecular transport in a vacuum environment,in the molecular flow *** Geant4 toolkit was originally developed by the high energy physics community to simulate the interactions of elemen-tary particles within complex detector *** its capabilities are utilized to model molecular vacuum transport in geometries where other techniques are *** techniques are verified with an application representing a simple vacuum geometry that has been studied previously both analytically and by basic Monte Carlo *** discuss the use of an application with a very complicated geometry,that of the Large Synoptic Survey Telescope camera cryostat,to determine probabilities of transport of contaminant molecules to optical surfaces where control of contamination is crucial.

关键词： Gas flow dynamics Monte Carlo methods vacuum systems pumping sys-tems contamination sources

Determination of gas reservoir(s) using AVO inversion within “XY” field offshore Niger Delta

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum Research 2019年第1期4卷 52-58页

作者： B.S.Ajanaku O.j.Akintorinwa Department of Applied Geophysics Federal University of TechnologyAkureNigeria

The AVO inversion analysis of pre-stack seismic data of“XY”field located within the offshore,Niger Delta Basin has been considered in this research work with the aim of using AVO inversion to delineate gas reservoirs within the *** different inversion techniques are carried out in order to obtain accurate reservoir *** conventional AVO inversion analysis of the field do not identify the gas reservoirs clearly as there are other zones without gas with similar signatures,however,the cross-plots analysis of elastic parameters and the inverted volumes are used to delineate two gas reservoirs at 2000 and 2100 ***,the inversion techniques help to map the reservoir zone in a better way by increasing the vertical *** inversion analysis as used in this research help for better understanding of the physical properties of the delineated reservoirs.

关键词： Pre-stack seismic Reservoir AVO inversion Cross-plots Compressional Shear wave

Fuzzy Logic Based Handover Authentication in 5g Telecommunication Heterogeneous Networks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer Systems Science & Engineering 2023年第7期46卷 1141-1152页

作者： j.Divakaran Arvind Chakrapani K.Srihari Vivekanandha College of Engineering for Women TiruchengodeNamakkal637205TamilnaduIndia Karpagam College of Engineering Coimbatore641032TamilnaduIndia SNS College of Technology Coimbatore641035TamilnaduIndia

Under various deployment circumstances,fifth-generation(5G)telecommunications delivers improved network compound management with fast communication *** to the introduction of the Internet of Things(IoT)in data management,the majority of the ultra-dense network models in 5G networks frequently have decreased spectral efficiency,weak handover management,and *** majority of traditional handover authentication models are seriously threatened,making them vulnerable to a variety of security *** authentication of networked devices is the most important ***,a model that incorporates the handover mechanism and authentication model must be *** article uses a fuzzy logic model to create a handover and key management system that focuses on cloud handover management and authentication *** order to decrease delays in 5G networks,the fuzzy logic is built with multiple criteria that aim to reduce the number of executed handovers and target cell *** simulation is run to evaluate the model’s performance in terms of latency,spatial complexity,and other metrics related to authentication attack validation.

关键词： Handover authentication mobility management fuzzy logic latency 5G IoT MATLAB 3gpp

Silvicultural alternatives to conventional even-aged forest man-agement-what limits global adoption?

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Forest Ecosystems 2015年第2期2卷 123-138页

作者： Klaus j Puettmann Scott McG Wilson Susan C Baker Pablo j Donoso Lars Dr?ssler Girma Amente Brian D Harvey Thomas Knoke Yuanchang Lu Susanna Nocentini Francis E Putz Toshiya Yoshida jürgen Bauhus Department of Forest Ecosystems and Society Oregon State University Consultant Forester and Forest Ecologist School ofBiological Sciences University of Tasmania Department of Forests and Society Faculty of Forest Sciences and Natural Resources Universidad Austral de Chile Southern Swedish Forest Research Centre Swedish Agricultural University Haramaya University Institut de recherche sur les forêts Université du Québec en Abitibi-Témiscamingue 445 Boulevard de l’Université Institute of Forest Management TUMSchool of Life Sciences Weihenstephan Technische Universit?t München Department of Forest Management and Statistics IFRIT Chinese Academy of Forestry Department of Agricultural Food and Forestry Systems University of Florence Department of Biology University of Florida Uryu Experimental Forest Field Science Center for Northern Biosphere Hokkaido University Chair of Silviculture Faculty of Environment and Natural Resources University of FreiburgTennenbacherstr

Background： The development of forestry as a scientific and management discipline over the last two centuries has mainly emphasized intensive management operations focused on increased commodity production, mostly wood. This conventionar＇ forest management approach has typically favored production of even-aged, single-species stands. While alternative management regimes have generally received less attention, this has been changing over the last three decades, especially in countries with developed economies. Reasons for this change include a combination of new information and concerns about the ecological consequences of intensive forestry practices and a willingness on the part of many forest owners and society to embrace a wider set of management objectives. Alternative silvicultural approaches are characterized by a set of fundamental principles, including avoidance of clearcutting, an emphasis on structural diversity and small-scale variability, deployment of mixed species with natural regeneration, and avoidance of intensive site-preparation methods. Methods： Our compilation of the authors＇ experiences and perspectives from various parts of the world aims to initiate a larger discussion concerning the constraints to and the potential of adopting alternative silvicultural practices. Results： The results suggest that a wider adoption of alternative silvicultural practices is currently hindered by a suite of ecological, economic, logistical, informational, cultural, and historical constraints. Individual contexts display their own unique combinations and relative significance of these constraints, and accordingly, targeted efforts, such as regulations and incentives, may help to overcome specific challenges. Conclusions： In a broader context, we propose that less emphases on strict applications of principles and on stand structures might provide additional flexibility and facilitate the adoption of alternative silvicultural regimes in a broader set of circumstanc

关键词： Natural Regeneration Forest Owner Stand Structure Commodity Production Private Landowner

维普期刊数据库

Grass Cover Influences Hydrophysical Parameters and Heterogeneity of Water Flow in a Sandy Soil

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2011年第6期21卷 719-729页

作者： L.LICHNER D.j.ELDRIDGE K.SCHACHT N.ZHUKOVA L.HOLKO M.íR j.PECHO Institute of Hydrology Slovak Academy of Sciences Department of Environment Climate Change and Water School of BiologicalEarth and Environmental SciencesUniversity of New South Wales Geography Department Ruhr-University BochumUniversitaetsstrasse M.Nodia Institute of Geophysics Institute of Hydrodynamics Academy of Sciences of the Czech Republic Institute of Atmospheric Physics Academy of Sciences of the Czech Republic

Vegetation cover has a major effect on water flow in soils. Two sites, separated by distance of about 50 m, were selected to quantify the influence of grass cover on hydrophysical parameters and heterogeneity of water flow in a sandy soil emerging during a heavy rain following a long hot, dry period. A control soil （pure sand） with limited impact of vegetation or organic matter was obtained by sampling at 50 cm depth beneath a glade area, and a grassland soil was covered in a 10 cm thick humic layer and colonised by grasses. The persistence of water repellency was measured using the water drop penetration time test, sorptivity and unsaturated hydraulic conductivity using a mini disk infiltrometer, and saturated hydraulic conductivity using a double-ring infiltrometer. Dye tracer experiments were used to assess the heterogeneity of water flow, and both the modified method for estimating effective cross section and an original method for assessing the degree of preferential flow were used to quantify this heterogeneity from the images of dyed soil profiles. Most hydrophysical parameters were substantially different between the two surfaces. The grassland soil had an index of water repellency about 10 times that of pure sand and the persistence of water repellency almost 350 times that of pure sand. Water and ethanol sorptivities in the grassland soil were 7% and 43%, respectively, of those of the pure sand. Hydraulic conductivity and saturated hydraulic conductivities in the grassland soil were 5% and 16% of those of the pure sand, respectively. Dye tracer experiments revealed a stable flow with ＂air-draining＂ condition in pure sand and well-developed preferential flow in grassland soil, corresponding to individual grass tussocks and sinai! micro-depressions. The grassland soil was substantially more water repellent and had 3 times the degree of preferential flow compared to pure sand. The results of this study reinforce our view that the consequences of any change in

关键词： dye tracing grassland soil hydrophobicity infiltration preferential flow

维普期刊数据库

Sediment loads response to climate change:A preliminary study of eight large Chinese rivers

在线全文

学校读者我要写书评

暂无评论

International journal of Sediment Research 2013年第1期28卷 1-14页

作者： X.X.LU L.S.RAN S.LIU T.jIANG S.R.ZHANG j.j.WANG Department of Geography National University of Singapore117570Singapore Global Change and Watershed Management Center Yunnan University of Finance and EconomicsYunnan National Climate Centre China Meteorological AdministrationBeijingChina College of Water Sciences Beijing Normal UniversityChina

Climate change characterized by increasing temperature is able to affect precipitation regime and thus surface ***,the manner in which river sediment loads respond to climate change is not well understood,and related assessment regarding the effect of climate change on sediment loads is *** present a quantitative estimate of changes in sediment loads(from 1.5 Gt yr-1pre-1990 to 0.6 Gt yr-1from 1991-2007) in response to climate change in eight large Chinese *** the past decades,precipitation change coupled with rising temperatures has played a significant role in influencing the sediment delivery dynamics,although human activities, such as reservoir construction,water diversion,sand mining and land cover change,are still the predominant forces. Lower precipitation coupled with rising temperatures has significantly reduced sediment loads delivered into the sea in semi-arid climates(4-61%).In contrast,increasingly warmer and wetter climates in subtropical zones has yielded more sediment(0.4-11%),although the increase was offset by human *** results indicate that,compared with mechanical retention by reservoirs,water reduction caused by climate change or human withdrawals has contributed more sediment reduction for the rivers with abundant sediment supply but limited transport capacity(e.g.,the Huanghe).Furthermore,our results indicate that every 1%change in precipitation has resulted in a 1.3%change in water discharge and a 2%change in sediment *** addition,every 1%change in water discharge caused by precipitation has led to a 1.6%change in sediment loads,but the same percentage of water discharge change caused largely by humans would only result in a 0.9%change in sediment *** figures can be used as a guideline for evaluating the responses of sediment loads to climate change in similar climate zones because future global warming will cause dramatic changes in water and sediment in river basins worldwide at rates previou

关键词： Sediment load Climate change Human activity Water withdrawal Chinese rivers

The Holocene Palaeoclimatic change in southern vicinity of Tengger Desert

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1999年第6期44卷 550-555页

作者： H.-j. Pachur B. Wuenneman Geomorphologic Lab. Institute of Geography FU BerlinGeomorphologic Lab. Institute of Geography FU Berlin 14195 Berlin Germany 14195 Berlin Germany

Through stratigraphy and chronology studies on Hongshui River section located at the southern vicinity of Tengger Desert, and based on the analysis results of TOC, TIC, elements, stable oxygen isotope that possess a h... 详细信息

关键词： Tengger Desert Holocene Paleaoclimate.

维普期刊数据库

Variations in total organic carbon and grain size distribution in ephemeral river sediments in western India

在线全文

学校读者我要写书评

暂无评论

International journal of Sediment Research 2011年第2期26卷 239-246页

作者： j.DINAKARAN N.S.R.KRISHNAYYA Ecology Laboratory Department of BotanyFaculty of ScienceM.S.University of Baroda

Total organic carbon(TOC) and grain size distribution(sand,silt,and clay) in the ephemeral Mahi River(western India) sediments were measured to look at their effectiveness in understanding the late Quaternary monsoon *** sites spread across the alluvial zone and three sites from the estuarine zone were *** concentration in the sediments of the alluvial and estuarine zone sites ranged between 0.04 and 0.39%and 0.04 and 0.23%,*** was observed that grain size differed significantly at the alluvial zone sites,whereas an uniform trend was found in the estuarine zone *** study indicated that low concentration of TOC and coarse size fractions(sand) in sediments were well correlated with available records of arid/weaker palaeomonsoon periods,whereas higher concentration of TOC and fine grain size fractions(silt + clay) in sediments were well correlated with available records of enhanced palaeomonsoon periods of the ephemeral Mahi *** concentrations of TOC and fine grain size particles in sediments at the estuarine zone sites are attributed to the backwater in the system,deeper sedimentation,and/or greater decomposition *** is concluded that,TOC and grain size distributions in the ephemeraL river sediments are simple and effective parameters to develop an understanding about late Quaternary monsoon conditions in ephemeral rivers.

关键词： Ephemeral river Fluvial sediments Total organic carbon Particle size distribution Quaternary monsoon