检索结果-南通市图书馆

Distribution and changes of active layer thickness(ALT) and soil temperature(TTOP) in the source area of the Yellow River using the GIPL model

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2014年第8期57卷 1834-1845页

作者： LUO DongLiang jIN Huijun Sergei MARCHENKO vladimir ROMANOVSKY State Key Laboratory of Frozen Soils Engineering Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences Geophysical Institute University of Alaska FairbanksFairbanks Alaska 99775 USA

Active layer thickness（ALT） is critical to the understanding of the surface energy balance, hydrological cycles, plant growth, and cold region engineering projects in permafrost regions. The temperature at the bottom of the active layer, a boundary layer between the equilibrium thermal state（in permafrost below） and transient thermal state（in the atmosphere and surface canopies above）, is an important parameter to reflect the existence and thermal stability of permafrost. In this study, the Geophysical Institute Permafrost Model（GIPL） was used to model the spatial distribution of and changes in ALT and soil temperature in the Source Area of the Yellow River（SAYR）, where continuous, discontinuous, and sporadic permafrost coexists with seasonally frozen ground. Monthly air temperatures downscaled from the CRU TS3.0 datasets, monthly snow depth derived from the passive microwave remote-sensing data SMMR and SSM/I, and vegetation patterns and soil properties at scale of 1：1000000 were used as input data after modified with GIS techniques. The model validation was carried out carefully with in-situ ALT in the SAYR interpolated from the field-measured soil temperature data. The results of the model indicate that the average ALT in the SAYR has significantly increased from 1.8 m in 1980 to 2.4 m in 2006 at an average rate of 2.2 cm yr–1. The mean annual temperature at the bottom of the active layer, or temperature at the top of permafrost（TTOP） rose substantially from –1.1°C in 1980 to –0.6°C in 2006 at an average rate of 0.018°C yr–1. The increasing rate of the ALT and TTOP has accelerated since 2000. Regional warming and degradation of permafrost has also occurred, and the changes in the areal extent of regions with a sub-zero TTOP shrank from 2.4×104 to 2.2×104 km2 at an average rate of 74 km2 yr–1. Changes of ALT and temperature have adversely affected the environmental stability in the SAYR.

关键词： GIPL model active layer thickness TTOP degradation of permafrost

The two faces of vaccine-induced immune response:protection or increased risk of HIV infection?!

在线全文

学校读者我要写书评

暂无评论

Virologica Sinica 2014年第1期29卷 7-9页

作者： vladimir Temchura Matthias Tenbusch Department of Molecular and Medical Virology Ruhr-University Bochum

Since the first HIV vaccine trial in1986 a variety of vaccination strategies have been developed and tested for immunogenicity in clinical phase I safety ***,only six vaccines have been approved for phaseⅡb/Ⅲefficac... 详细信息

关键词：疫苗接种 HIV 感染率免疫反应保护危险性诱导疫苗试验

Self-assembled formation of long, thin, and uncoalesced GaN nanowires on crystalline TiN films

在线全文

学校读者我要写书评

暂无评论

Nano Research 2018年第1期11卷 565-576页

作者： David van Treeck Gabriele Calabrese jelle j. W. Goertz vladimir M. Kaganer Oliver Brandt Sergio Fernandez-Garrido, Lutz Geelhaar PauI-Drude-lnstitut f~r Festk6rperelektronik Leibniz-lnstitut im Forschungsverbund Berlin e.V. Hausvogteiplatz 5-7 I 0117 Berlin Germany

We investigate in detail the self-assembled nucleation and growth of vertically oriented GaN nanowires by molecular beam epitaxy on crystalline TiN films. We demonstrate that this type of substrate allows for the growth of long and thin GaN nanowires that do not suffer from coalescence, a problem common to the growth on Si and other substrates. Only beyond a certain nanowire length that depends on the nanowire density and exceeds here 1.5 bun, coalescence takes place by bundling, i.e. the same process as on Si. By analyzing the nearest neighbor distance distribution, we identify the diffusion-induced repulsion of neighboring nanowires as the main mechanism limiting nanowire density during nucleation on TiN. Since on Si the final density is determined by shadowing of the impinging molecular beams by existing nanowires, it is the difference in adatom surface diffusion that enables the formation of nanowire ensembles with reduced density on TiN. These nanowire ensembles combine properties that make them a promising basis for the growth of core-shell heterostructures.

关键词： nanocolumn gallium nitride nucleation metal substrate coalescence core-shell

Impact of Zener-Hollomon parameter on substructure and texture evolution during thermomechanical treatment of iron-containing wrought aluminium alloys

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2019年第5期29卷 893-906页

作者： Evgenii ARYSHENSKII jürgen HIRSCH vladimir BAZHIN Rudolf KAWALLA Ulrich PRAL TU Bergakademie Freiberg Institut für Metallformung Samara State Aerospace University Samara National Research University Hydro Aluminium Rolled Products GmbH Research and Development St.Petersburg Mining University Institute of Automation of Manufacturing Processes

The objective of the investigation is to evaluate the influence of the Zener-Hollomon parameter on substructure and texture evolution in iron-containing wrought aluminium alloys (type AA8011). Methods applied are X-ray texture analysis, electron backscatter diffraction (EBSD) and optical microscopy. The results show a serious impact of the Zener-Hollomon parameter on cube texture evolution during the thermomechanical treatment in iron-containing aluminium alloys. An increase in the Zener-Hollomon parameter reduces the survivability of cube texture during hot deformation and reinforces particle-stimulated nucleation (PSN) during the annealing process. However, thermomechanical treatment at low temperatures leads to active precipitation and as a result fine-dispersed participles tend to block all nuclei except for those producing large cube-oriented grains. It is concluded that in iron-containing wrought aluminium alloys, the general correlation between the Zener-Hollomon parameter and subgrain size is similar to that observed in 3xxx series alloys and can be described by the specific set of equations derived.

关键词： aluminium alloy texture Zener-Hollomon parameter substructure hot rolling

First Insights into the Viral Communities of the Deep-sea Anoxic Brines of the Red Sea

在线全文

学校读者我要写书评

暂无评论

Genomics, Proteomics & Bioinformatics 2015年第5期13卷 304-309页

作者： Andr Antunes Intikhab Alam Marta Filipa Simoes Camille Daniels Ari j.S.Ferreira Rania Siam Hamza El-Dorry vladimir B.Bajic Computational Bioscience Research Center (CBRC) ComputerElectrical and Mathematical Sciences and Engineering Division (CEMSE)King Abdullah University of Science and Technology (KAUST) Red Sea Research Center (RSRC) Biological and Environmental Sciences and Engineering Division (BESE)King Abdullah University of Science and Technology (KAUST) Biology Department American University in Cairo

The deep-sea brines of the Red Sea include some of the most extreme and unique envi- ronments on Earth. They combine high salinities with increases in temperature, heavy metals, hydrostatic pressure, and anoxic conditions, creating unique settings for thriving populations of novel extremophiles. Despite a recent increase of studies focusing on these unusual biotopes, their viral communities remain unexplored. The current survey explores four metagenomic datasets obtained from different brine-seawater interface samples, focusing specifically on the diversity of their viral communities. Data analysis confirmed that the particle-attached viral communities present in the brine-seawater interfaces were diverse and generally dominated by Candovirales, yet appearing distinct from sample to sample. With a level of caution, we report the unexpected finding of Phycodnaviridae, which infects algae and plants, and trace amounts of insect-infecting Iridoviridae. Results from Kebrit Deep revealed stratification in the viral communities present in the interface： the upper-interface was enriched with viruses associated with typical marine bacteria, while the lower-interface was enriched with haloviruses and halophages. These results provide first insights into the unexplored viral communities present in deep-sea brines of the Red Sea, represent- ing one of the first steps for ongoing and future sampling efforts and studies.

关键词： Viral diversity Metagenomics Brine-seawater interface Caudovirales Red Sea

Overcoming thermo-optical dynamics in broadband nanophotonic sensing

在线全文

学校读者我要写书评

暂无评论

Microsystems & Nanoengineering 2021年第4期7卷 47-57页

作者： Mingkang Wang Diego j.Perez-Morelo vladimir Aksyuk Microsystems and Nanotechnology Division National Institute of Standards and TechnologyGaithersburgMD 20899USA Institute for Research in Electronics and Applied Physics University of MarylandCollege ParkMD 20742USA

Advances in integrated photonics open up exciting opportunities for batch-fabricated optical sensors using high-quality-factor nanophotonic cavities to achieve ultrahigh sensitivities and *** sensitivity improves with increasing optical power;however,localized absorption and heating within a micrometer-scale mode volume prominently distorts the cavity resonances and strongly couples the sensor response to thermal dynamics,limiting the sensitivity and hindering the measurement of broadband time-dependent ***,we derive a frequency-dependent photonic sensor transfer function that accounts for thermo-optical dynamics and quantitatively describes the measured broadband optomechanical signal from an integrated photonic atomic force microscopy nanomechanical *** this transfer function,the probe can be operated in the high optical power,strongly thermo-optically nonlinear regime,accurately measuring low-and intermediate-frequency components of a dynamic signal while reaching a sensitivity of 0.7fm/Hz^(1/2) at high frequencies,an improvement of=10x relative to the best performance in the linear ***,we discover that a higher transduction gain and sensitivity are achieved with lower quality-factor optical modes for low signal *** limited to optomechanical transducers,the derived transfer function is generally valid for describing the small-signal dynamic responses of a broad range of technologically important photonic sensors subject to the thermo-optical effect.

关键词： dynamics regime hinder

Biological Dose Estimation Model for Proton Beam Therapy

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 Medical Physics, Clinical Engineering and Radiation Oncology 2015年第2期4卷 149-161页

作者： vladimir Anferov Indra j. Das Pronova Solutions LLC Knoxville USA Indiana University School of Medicine Indianapolis USA IU Health Proton Therapy Center Bloomington USA

Purpose: The recommended value for the relative biological effectiveness (RBE) of proton beams is currently assumed to be 1.1. However, there is increasing evidence that RBE increases towards the end of proton beam range that may increase the biological effect of proton beam in the distal regions of the dose deposition. Methods: A computational approach is presented for estimating the biological effect of the proton beam. It includes a method for calculating the dose averaged linear energy transfer (LET) along the measured Bragg peak and published LET to RBE conversion routine. To validate the proposed method, we have performed Monte Carlo simulations of the pristine Bragg peak at various beam energies and compared the analysis with the simulated results. A good agreement within 5% is observed between the LET analysis of the modeled Bragg peaks and Monte Carlo simulations. Results: Applying the method to the set of Bragg peaks measured at a proton therapy facility we have estimated LET and RBE values along each Bragg peak. Combining the individual RBE-weighted Bragg peaks with known energy modulation weights we have calculated the RBE-weighted dose in the modulated proton beam. The proposed computational method provides a tool for calculating dose averaged LET along the measured Bragg peak. Conclusions: Combined with a model to convert LET into RBE, this method enables calculation of RBE-weighted dose both in pristine Bragg peak and in modulated beam in proton therapy.

关键词： Proton Beam Therapy Relative Biological Effectiveness Linear Energy Transfer

Separation of Soybean Oil/n-hexane Miscellas Using Polymeric Membranes

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 Food Science and Engineering 2012年第11期2卷 616-624页

作者： Marcus V. Tres jéssica C. Racoski Zuleica Novello jonas R.M. de Melo Helen C. Ferraz Marco DiLuccio josé vladimir oliveira: Department of Food Engineering URI-Campus de Erechim Av. Sete de Setembro 1621 Erechim 99700-000 RS Brazil Program of Chemical Engineering COPPE UFRJ-Centro de Tecnologia Bloco G Sala 115 Rio de Janeiro 21941-972 R JBrazil

Separation of refined soybean oil/n-hexane miscellas was studied using different commercial ultra- and nanofiltration membranes, with cut-oil＇s in the range of 1 to 5 kDa and salt rejection higher than 97% （MgSO4）. Commercial soybean oil and n-hexane miscellas with 1：3 and 1：1 mass ratios were permeated in a dead-end module. The effects of the feed pressure （2-25 bar） on oil and n-hexane fluxes and rejection were investigated. Oil rejection ranged from negative values to 30.8%, soybean oil flux from 28.9 to 617.8 g/m2 hl and n-hexane flux from 8.5 to 1,078.5 g m2 hl. Membrane fouling was observed at all experimental conditions studied. The membrane separation process has proven to be a promising alternative to solvent recovery in soybean oil extraction.

关键词： Soybean oil n-hexane ultrafiltration nanofiltration polymeric membranes.

Cognitive Supervisor for an Autonomous Swarm of Robots

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Intelligent Control and Automation 2017年第1期8卷 44-65页

作者： vladimir G.Ivancevic Darryn j.Reid Decision Sciences Joint and Operations Analysis DivisionDefence Science&Technology GroupCanberraAustralia

As a sequel to our recent work [1], in which a control framework was developed for large-scale joint swarms of unmanned ground (UGV) and aerial (UAV) vehicles, the present paper proposes cognitive and meta-cognitive supervisor models for this kind of distributed robotic system. The cognitive supervisor model is a formalization of the recently Nobel-awarded research in brain science on mammalian and human path integration and navigation, performed by the hippocampus. This is formalized here as an adaptive Hamiltonian path integral, and efficiently simulated for implementation on robotic vehicles as a pair of coupled nonlinear Schr?dinger equations. The meta-cognitive supervisor model is a modal logic of actions and plans that hinges on a weak causality relation that specifies when atoms may change their values without specifying that they must change. This relatively simple logic is decidable yet sufficiently expressive to support the level of inference needed in our application. The atoms and action primitives of the logic framework also provide a straight-forward way of connecting the meta-cognitive supervisor with the cognitive supervisor, with other modules, and to the meta-cognitive supervisors of other robotic platforms in the swarm.

关键词： Autonomous Robotic Swarm Cognitive Supervisor Hippocampus Path Integration and Navigation Hamiltonian Path Integral Modal Logic Nonlinear Schrodinger Equation Reasoning about Actions and Plans