检索结果-南通市图书馆

The role of isotropic and anisotropic Hubbard corrections for the magnetic ordering and absolute band alignment of hematite α-Fe2O3(0001)surfaces

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2019年第3期29卷 349-355页

作者： Sateesh Bandaru Ivan Scivetti Chi-yung Yam Gilberto Teobaldi School of Chemical and Bioprocess Engineering University College Dublin Beijing Computational Science Research Center Stephenson Institute for Renewable Energy Department of ChemistryThe University of Liverpool Scientific Computing Department Science and Technology Facilities CouncilDaresbury Laboratory

An isotropic (+U) and anisotropic [+(U-J)] corrected Density Functional Theory study for bulk hematite (α-Fe2O3) was carried out,and several competing terminations of its (0001) surface modeled via slabs of increasing thickness from twelve to thirty-six *** spite of small quantitative differences,the use of either U or (U-J)corrections showed not to qualitatively affect the results of the simulations both for bulkα-Fe2O3and the lowestenergyα-Fe2O3(0001) surface studied,regardless of the thickness of the slab *** energy favored antiferromagnetic ordering of bulkα-Fe2O3was preserved in the relaxed slabs,with the largest surface-induced effects limited to the outermost three Fe-layers in the *** O-and Fe-terminations were found to be energetically favored and ***,fully O-or Fe-terminated surfaces were calculated to be energetically disfavored and ***,the role of Fe-or O-termination for the semiconducting or metallic nature as well as absolute band alignment ofα-Fe2O3(0001) surfaces was analyzed and discussed with respect to the challenges in enhancing the activity ofα-Fe2O3samples as photo-electrode for water splitting.

关键词： Hematite α-Fe2O3 Surfaces Photo-electrodes Density functional theory Electronic properties Magnetic properties

Sensitivity of precipitation statistics to urban growth in a subtropical coastal megacity cluster

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2017年第9期29卷 6-12页

作者： Christopher Claus Holst Johnny C.L.Chan Chi-yung Tam School of Energy and Enuironment City Uniuersity of liong KongHong KongChina Guy Carpenter Asia-Pacific Climate Impact Centre City Uniuersity of Hong KongHong KongChina Earth System Science Programme The Chinese Uniuersity of Hong KongHong KongChina

This short paper presents an investigation on how human activities may or may not affect precipitation based on numerical simulations of precipitation in a benchmark case with modified lower boundary conditions, representing different stages of urban development in the model. The results indicate that certain degrees of urbanization affect the likelihood of heavy precipitation significantly, while less urbanized or smaller cities are much less prone to these effects. Such a result can be explained based on our previous work where the sensitivity of precipitation statistics to surface anthropogenic heat sources lies in the generation of buoyancy and turbulence in the planetary boundary layer and dissipation through triggering of convection. Thus only mega cities of sufficient size, and hence human-activity-related anthropogenic heat emission, can expect to experience such effects. In other words, as cities grow, their effects upon precipitation appear to grow as well.

关键词： Urban precipitation Micro climate sensitivity Urbanization

Horizontal gas mixing in rectangular fluidized bed:A novel method for gas dispersion coefficients in various conditions and distributor designs

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2017年第7期25卷 848-861页

作者： Asheesh Nautiyal Chien-Song Chyang Pin-Wei Li Hsin-yung Hou Department of Chemical Engineering Chung Yuan Christian UniversityTaoyuan 320TaiwanChina

In a rectangular fluidized bed combustor, the tracer gas is injected continuously into the bed from a point source at the center of the distributor plate. In this study, a general governing equation is formulated for tracer gas dispersion in the bed. An analytical solution is derived to estimate the dispersion coefficients, Dxand Dy, in a horizontal plane. The concentration profiles at different sampling heights with various gas velocities are ***, to estimate the dispersion coefficients, surface fitting of the obtained analytical solution to the experimental data is performed. The dispersion coefficients obtained from this model are compared with those of a conventional model. Additionally, the effect of walls, bed height and gas injection rate on the dispersion coefficients in a horizontal plane is investigated, and the effect of distributor design on the dispersion coefficients in a horizontal plane is investigated with different tracer positions. It is found that Dxand Dyare nearly equivalent at a lower tracer gas ratio of the injected gas to the total gas flow rate. It is also demonstrated that the effect of bed height on Dxis minor. This model is also able to estimate the dispersion coefficients in the case of a multihorizontal nozzle distributor.

关键词： Gas dispersion coefficient Horizontal mixing Wall effect Surface modeling

Experimental and Modeling Studies on the Chemical Vapor Infiltration with Respect to the Effects of Thermal Gradient and Other Operating Parameters

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2018年第3期33卷 525-532页

作者： Kyung Do Joo Do Hoon Kim Gui yung Chung Department of Chemical Engineering Hong Ik University

Effects of operating parameters in the thermal gradient chemical vapor infiltration of propane such as thermal gradient, diffusion, infiltrations time, and concentration of propane were studied by focusing on the visualizations of the intrinsic effects of these parameters. A uniform deposition in the preform was obtained with a gradually increasing temperature along the gas flow. The uniformity of deposition through the preform got improved with increasing deposition time. Results of numerical modeling estimated the experimental data very well when the pre-exponential factor of the overall rate of carbon deposition from propane reported by Vaidyaraman[1] was multiplied by 4. The average density of a preform increased by about 3 times from 0.38 to 1.15 g/cm3 after 60 hr deposition with a thermal gradient under the conditions of 3% propane in nitrogen and 840 to 900 ℃.

关键词： TG-CVI propane C/C composites uniform deposition mathematical modeling

Human-Animal Interactions in Disaster Settings:A Systematic Review

在线全文

学校读者我要写书评

暂无评论

International Journal of Disaster Risk Science 2023年第3期14卷 369-381页

作者： Haorui Wu Lindsay K.Heyland mandy yung Maryam Schneider School of Social Work Faculty of HealthDalhousie UniversityHalifaxNS B3H 4R2Canada Department of Psychology Mount Saint Vincent UniversityHalifaxNSB3M2J6Canada

This systematic review aimed to assess the current knowledge of human-animal interactions(HAIs)in disaster settings and identify areas for future research.A Preferred Reporting Items for Systematic Reviews and Meta-Analyses search was conducted on three multidisciplinary databases,identifying English-language journal articles published between January 2000and February 2022 that explored the benefits of and challenges associated with HAI in disasters and *** review analyzed 94 articles using both quantitative and qualitative *** review found a paucity of universal terminology to describe the bidirectional relationship between humans and animals during disasters and a failure to include all animal types in every stage of disaster and emergency ***,research predominantly focused on the health and well-being benefits of HAI for humans rather than *** to promote social and environmental justice for humans and their co-inhabitants should support the welfare of both humans and animals in disaster *** recommendations were developed based on these findings to increase the inclusion of HAI in research,policy,and *** of the review included the exclusion of pre-2000 articles and all grey literature,limited research examining different combinations of animal and disaster types,and limited research outside of North America.

关键词： Emergency management Hazards and disaster research Human-animal bonds Human-animal interactions Human-animal welfare Inclusive Literature review

Coinfection of TT virus and response to interferon therapy in patients with chronic hepatitis B or C

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2002年第3期8卷 567-570页

作者： yung-ChihLai Ruey-TyngHu Sien-SingYang Chi-HwaWu Liver Unit Department of Internal MedicineCathay General HospitalTaipeiTaiwan

AIM: To investigate the serum positive percentage of TT virus (TTV) in patients with chronic hepatitis B or C and the response of the coinfected TTV to interferon (IFN) during IFN therapy for chronic hepatitis B and C. METHODS: We retrospectively studied the serum samples of 70 patients with chronic hepatitis who had received IFN-alpha therapy from January 1997 to June 2000, which included 40 cases of hepatitis B and 30 hepatitis C. All the patients had been followed up for at least 6 months after the end of IFN therapy. The serum TTV DNA was detected using the polymerase chain reaction (PCR) before and every month during the course of IFN treatment. RESULTS: TTV infection was detected in 15% (6/40) of the chronic hepatitis B group and 30% (9/30) of the chronic hepatitis C group. Loss of serum TTV DNA during IFN therapy occurred in 3 of 6 patients (50%) and 6 of 9 (67%) of hepatitis B and C groups, respectively. Seronegativity of TTV was found all during the first month of IFN therapy in the 9 patients. There was no correlation between the seroconversion of TTV and the biochemical changes of the patients. CONCLUSION: TTV is not infrequently coinfected in patients with chronic hepatitis B and C in Taiwan, and more than half of the TTV infections are IFN-sensitive. However, the loss of serum TTV DNA does not affect the clinical course of the patients with chronic hepatitis B or C.

关键词： Torque teno virus Adult DNA Virus Infections Female Hepatitis B, Chronic Hepatitis C, Chronic Humans Interferon-alpha Male Middle Aged Retrospective Studies

The Shanghai Corporate Pavilion design for World Expo in Shanghai 2010

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2010年第4期4卷 519-521页

作者： yung Ho CHANG Department of Architecture Massachusetts Institute of TechnologyMassachusetts MA 02139USA Atelier FCJZBeijing 10084China

New technologies are becoming today’s basic building *** paper presents a case study of the Shanghai Corporate Pavilion for the 2010World Expo in *** the shape of the building to the use of solar energy,the Shanghai Corporate Pavilion incorporates the state-of-art technologies to convey the spirit of the *** addresses the pressing issue of energy,environment,and sustainability and reflects the spirit of Shanghai as a historically progressive yet still fast moving international metropolis.

关键词： 2010World Expo LED lights solar energy

Numerical study on Rayleigh-Taylor effect on cylindrically converging Richtmyer-Meshkov instability

维普期刊数据库评论

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(Physics,Mechanics & Astronomy) 2019年第12期62卷 68-77页

作者： ZhiGang Zhai Fu Zhang ZhangBo Zhou JuChun Ding Chih-yung Wen Department of Modern Mechanics University of Science and Technology of ChinaHefei 230026China Beijing Institute of Space Long March Vehicle Beijing 100076China Department of Mechanical Engineering The Hong Kong Polytechnic UniversityHong Kong 999077China

Evolution of a two-dimensional air/SF6 single-mode interface is numerically investigated by an upwind CE/SE method under a cylindrically converging circumstance. The Rayleigh-Taylor effect caused by the flow deceleration on the phase inversion(RTPI)is highlighted. The RTPI was firstly observed in our previous experiment, but the related mechanism remains unclear. By isolating the three-dimensional effect, it is found here that the initial amplitude(a0), the azimuthal mode number(k0) and the re-shocking moment are the three major parameters which determine the RTPI occurrence. In the variable space of(k0, a0), a critical a0 for the RTPI occurrence is solved for each k0, and there exists a threshold value of k0 below which the RTPI will not occur no matter what a0 is. There exists a special k0 corresponding to the largest critical a0, and the reduction rule of critical a0 with k0 can be well described by an exponential decay function. The results show that the occurrence of the RTPI requires a small a0 which should be less than a critical value, a large k0 which should exceed a threshold, and a right impinging moment of the re-shock which should be later than the RTPI occurrence. Finally, the effects of the incident shock strength, the density ratio and the initial position of the interface on the threshold value of k0 and on the maximum critical a0 are examined. These new findings would facilitate the understanding of the converging Richtmyer-Meshkov instability and would be helpful for designing an optimal structure of the inertia confinement fusion capsule.

关键词： converging shock wave Rayleigh-Taylor effect Richtmyer-Meshkov instability

Cooperative Spectrum Sensing in Cognitive Radio Using Bayesian Updating with Multiple Observations

在线全文

学校读者我要写书评

暂无评论

Journal of Electronic Science and Technology 2019年第3期17卷 252-259页

作者： yung-Fa Huang Jyu-Wei Wang the Department of Information and Communication Engineering Chaoyang University of TechnologyTaichung 41368 the Department of Photonics and Communication Engineering Asia UniversityTaichung 41354

We study cooperative spectrum sensing in cognitive radio (CR) networks using the hidden Markov model (HMM) for opportunistic spectrum access (OSA). We assume that the primary channel operates in a time division multiple address (TDMA) manner. Thus, spectrum sensing is operating in a slot-by-slot basis. In contrast to the conventional Bayesian updating using only one observation, in this work, we propose to perform the update in a concatenated fashion with all the observations available from the secondary users (SUs). In the proposed scheme, a predefined threshold on the belief is used for determining the channel activity. With the threshold, the proposed scheme is more flexible in the system operation than the simple majority vote scheme, in which no such threshold is available. We compare, by simulations, the performance of the proposed concatenated update scheme with that of the majority vote scheme and show that the probabilities of correctly detecting a busy state and an idle state are about 1 as the number of SUs is as large as 15, so the effects of the further increase in the number of SUs are limited.

关键词： Bayesian updating cognitive radio(CR) cooperative sensing hidden Markov model(HMM)