检索结果-南通市图书馆

Fabrication of Core-Shell Hydrogel Bead Based on Sodium Alginate and Chitosan for Methylene Blue Adsorption

在线全文

学校读者我要写书评

暂无评论

Journal of Renewable Materials 2024年第4期12卷 815-826页

作者： xiaoyu Chen School of Material Engineering Jinling Institute of TechnologyNanjing211169China

A novel core-shell hydrogel bead was fabricated for effective removal of methylene blue dye from aqueous *** core,made of sodium alginate-g-polyacrylamide and attapulgite nanofibers,was cross-linked by Calcium ions(Ca^(2+)).The shell,composed of a chitosan/activated carbon mixture,was then coated onto the *** transform infrared spectroscopy confirmed the grafting polymerization of acrylamide onto sodium *** electron microscopy images showed the core-shell *** core exhibited a high water uptake ratio,facilitating the diffusion of methylene blue into the *** the diffusion process,the methylene blue was first adsorbed by the shell and then further adsorbed by the *** tests showed that the coreshell structure had a larger adsorption capacity than the core *** shell effectively enhanced the adsorption capacity to methylene blue compared to the single *** blue was adsorbed by activated carbon and chitosan in the shell,and the residual methylene blue diffused into the core and was further adsorbed.

关键词： Core-shell structure hydrogel bead attapulgite nanofiber sodium alginate polyacrylamide methylene blue adsorption material

Triad-displaced ULAs configuration for non-circular sources with larger continuous virtual aperture and enhanced degrees of freedom

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 Systems Engineering and Electronics 2024年第1期35卷 81-93页

作者： SHAIKH Abdul Hayee DANG xiaoyu HUANG Daqing College of Electronic and Information Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China

Non-uniform linear array(NULA)configurations are well renowned due to their structural ability for providing increased degrees of freedom(DOF)and wider array aperture than uniform linear arrays(ULAs).These characteristics play a significant role in improving the direction-of-arrival(DOA)estimation ***,most of the existing NULA geometries are primarily applicable to circular sources(CSs),while they limitedly improve the DOF and continuous virtual aperture for noncircular sources(NCSs).Toward this purpose,we present a triaddisplaced ULAs(Tdis-ULAs)configuration for *** TdisULAs structure generally consists of three ULAs,which are appropriately *** proposed antenna array approach fully exploits the non-circular characteristics of the *** the same number of elements,the Tdis-ULAs design achieves more DOF and larger hole-free co-array aperture than its sparse array ***,the number of uniform DOF,optimal distribution of elements among the ULAs,and precise element positions are uniquely determined by the closed-form ***,the proposed array also produces a filled resulting *** simulations are conducted to show the performance advantages of the proposed Tdis-ULAs configuration over its counterpart designs.

关键词： direction-of-arrival(DOA)estimation sparse array non-circular source(NCS) sum co-array difference co-array degrees of freedom(DOF)

AWells-Riley/based COVID-19 infectiousrisk assessment model combining both short rangeandroom scale effects

在线全文

学校读者我要写书评

暂无评论

Building Simulation 2024年第1期17卷 93-111页

作者： Yinshuai Feng Yifan Fan xiaoyu Luo Jian Ge College of Civil Engineering and Architecture Zhejiang UniversityHangzhouChina Center for Balance Architecture Zhejiang UniversityHangzhouChina International Research Center for Green Building and Low-Carbon City International CampusZhejiang UniversityHainingChina

There is growing evidence of the high transmission potential of COVID-19 through virus-laden *** aerosols are inhaled in various concentrations,an overall assessment of transmission risks at different indoor scales is ***,a comprehensive risk assessment method that evaluates the direct link between short-range and room-scale zones is stl *** this paper,a risk assessment model combining both short-range and room-scale effects is developed to obtain effective reproduction number in confined indoor environments,called Turbulent Jet Wells Riley(TJWR)*** with the viral load data and aerosol generation data of different human respiratory activities,the Monte Carlo simulation method is applied to calculate the quanta emission rate,which further provides the input parameters of the TJWR *** known outbreaks(Hangzhou banquet hall X,Guangzhou restaurant Y,and Hong Kong restaurant Z,China)are chosen to validate the TJWR *** show that the TJWR model is more efficient than the original Wells-Riley *** average relative error of the TJWR model ranges between 9%and 4.%,while for the Wells-Riley model,it ranges between 57%and 78%.The TJWR model also proves that infection risk assessments using the well-mixed assumption can systematically underestimate the transmission risk for those close to the ***,there is a significant positive linear correlation between the total number of exposed individuals at the short-range and the effective reproduction *** newly developed TJWR model has great potential for rapid and real-time overall airborne transmission risk assessment in buildings and cities.

关键词： COVID-19 airborne transmission infection risk Wells-Riley model Monte Carlo simulation

A high-order target phase approach for the station-keeping of periodic orbits

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Astrodynamics 2024年第1期8卷 61-75页

作者： xiaoyu Fu Nicola Baresi Roberto Armellin Surrey Space Centre University of SurreyGuildfordGU27XHUK Te PūnahaĀtea-Auckland Space Institute University of AucklandAuckland1010New Zealand

A novel high-order target phase approach(TPhA)for the station-keeping of periodic orbits is proposed in this *** key elements of the TPhA method,the phase-angle Poincare map and high-order maneuver map,are constructed using differential algebra(DA)techniques to determine station-keeping epochs and calculate correction maneuvers.A stochastic optimization framework tailored for the TPhA-based station-keeping process is leveraged to search for fuel-optimal and error-robust TPhA ***-satellite orbits(QSOs)around Phobos are investigated to demonstrate the efficacy of TPhA in mutli-fidelity dynamical *** Carlo simulations demonstrated that the baseline QSO of JAXA’s Martian Moons eXploration(MMX)mission could be maintained with a monthly maneuver budget of approximately 1 m/s.

关键词： target phase approach(TPhA) station-keeping Poincarémap differential algebra(DA) quasi-satellite orbit(QSO)

Effects of physical properties of supercritical water on heat transfer characteristics of single particle within a particle cluster Author links open overlay panel

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2024年第8期91卷 291-302页

作者： xiaoyu Li Bowei Zhang Huibo Wang Hui Jin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an710049China

The complex physical properties of supercritical water(SCW)make the heat transfer characteristics of particles within a particle cluster *** heat transfer characteristics of single particle within a particle cluster in SCW,influenced by surrounding particles,have not been effectively *** numerical simulations were conducted to investigate the heat transfer characteristics of particle clusters in SCW under different *** results were compared and analyzed with those from constant property *** was found that Reynolds number(Re)and the void fraction of particle cluster have no special effects on the variation trends of Nusselt number(Nu)for the focused ***,the particle temperature had a significant effect on the variation trends of *** effect of Re on the heat transfer rate exponent(η)of the focused particle can be divided into two zones:a significant effect zone and a non-significant effect *** effect of void fraction onηin the non-significant effect zone was *** the non-significant effect zone,ηdecreased with the increasing particle *** the significant effect zone,the variation trends ofηbecame more *** fundamental reason for this series of phenomena is the changes in distribution of physical properties.A model forηwas developed for the non-significant effect *** model can filter out the effects of Re and certain particle cluster spatial configurations,and it demonstrates good predictive performance.

关键词： Supercritical water Particle cluster Heat transfer characteristics Heat transfer rate exponent Physical properties correction

Synthesis of chitosan-based grafting magnetic flocculants for flocculation of kaolin suspensions

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 Environmental Sciences 2024年第5期139卷 193-205页

作者： Chuang Liu xiaoyu Wang Sicong Du Wenyan Liang Beijing Key Lab for Source Control Technology of Water Pollution/Engineering Research Center for Water Pollution Source Control&Eco-remediation/College of Environmental Science and Engineering Beijing Forestry UniversityBeijing 100083China

A series of novel chitosan-based magnetic flocculants FS@CTS-P(AM-DMC)was prepared by molecular structure *** characterization results showed that FS@CTS-P(AM-DMC)had a uniform size of about 21.4. nm,featuring a typical core-shell structure,and the average coating layer thickness of CTS-P(AM-DMC)was about 5.03 ***@CTS-P(AM-DMC)exhibited excellent flocculation performance for kaolin suspension,achieved 92.54. turbidity removal efficiency under dosage of 150 mg/L,pH 7.0,even at high turbidity(2000 NTU)with a removal efficiency of 96.96%.The flocculation mechanism was revealed to be dominated by charge neutralization under acidic and neutral conditions,while adsorption and bridging effects play an important role in alkaline *** properties of magnetic aggregates during flocculation,breakage,and regeneration were studied at different pH levels and *** the process of magnetophoretic,magnetic particles collide and adsorb with kaolin particles continuously due to magnetic and electrostatic attraction,transform into magnetic chain clusters,and then further form three-dimensional network magnetic aggregates that can capture free kaolin particles and other chain *** image velocimetry confirmed the formation of eddy current of magnetic flocs and experienced three stages:acceleration,stabilization,and deceleration.

关键词： Magnetic flocculation Chitosan Fe_(3)O_(4. Graft copolymerization PIV

Theoretical model of azimuthal combustion instability subject to non-trivial boundary conditions

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第9期37卷 113-130页

作者： Lei QIN xiaoyu WANG Guangyu ZHANG Xiaofeng SUN Research Institute of Aero-Engine Beihang UniversityBeijing 100191China School of Energy and Power Engineering Beihang UniversityBeijing 100191China

The problem of evaluating the sensitivity of non-trivial boundary conditions to the onset of azimuthal combustion instability is a longstanding challenge in the development process of mod-ern gas *** difficulty lies in how to describe three-dimensional in-and outlet boundary conditions in an artificial computational *** date,the existing analytical models have still failed to quantitatively explain why the features of the azimuthal combustion instability of a com-bustor in laboratory environment are quite different from that in a real gas turbine,making the sta-bility control devices developed in laboratory generally lose the effectiveness in practical *** overcome this limitation,we provide a novel theoretical framework to directly include the effect of non-trivial boundary conditions on the azimuthal combustion instability.A key step is to take the non-trivial boundary conditions as equivalent distributed sources so as to uniformly describe the physical characteristics of the inner surface in an annular enclosure along with different in-and outlet ***,a dispersion relation equation is established by the application of three-dimensional Green's function approach and generalized impedance *** show that the effects of the generalized modal reflection coefficients on azimuthal unstable modes are extremely prominent,and even prompt the transition from stable to unstable mode,thus reasonably explaining why the thermoacoustic instability phenomena in a real gas tur-bine are difficult to observe in an isolated combustion ***,this work provides an effective tool for analysis of the azimuthal combustion instability including various complicated boundary conditions.

关键词： Combustion instability Aeroacoustics Modeling Optimization techniques Control

Catalytic Asymmetric Synthesis of Inherently Chiral Saddle- Shaped Dibenzo[b,fI[1,5]diazocines

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 Journal of Chemistry 2024年第17期42卷 1953-1959页

作者： Jinmiao Zhou Mengyao Tang xiaoyu Yang Schoolof Physical Science and Technology ShanghaiTech UniversityShanghai 201210China

Dibenzo[b,fi[1,5]diazocines are a class of eight-membered heterocycles,which exhibit unique rigid saddle-shaped structure and possess inherent *** this study,we report a convenient and straightforward method for the catalytic enantioselective synthesis of these unique chiral molecules through chiral phosphoric acid-catalyzed dimerization of ***,the addition of corresponding 2-acylaniline as the co-catalyst significantly improved the efficiency of these reactions,and a simple phase separation operation resulted in products with excellent *** studies were performed to elucidate the mechanism behind these reactions,leading to the proposal of a plausible reaction mechanism based on the study findings.

关键词： Dibenzo[b,f]diazocines Saddle-shaped inherent chirality Organocatalysis Asymmetric catalysis Medium-ring compounds Cooperativecatalysis Chiral phosphoricacids

Four-to Six-Year Periodic Variation of Arctic Sea-Ice Extent and Its Three Main Driving Factors

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2024年第10期41卷 1999-2010页

作者： Ping CHEN Jinping ZHAO xiaoyu WANG Institute of Oceanographic Instrumentation Qilu University of Technology(Shandong Academy of Sciences)Qingdao 266000China College of Oceanic and Atmospheric Sciences Ocean University of ChinaQingdao 266000China Frontiers Science Center for Deep Ocean Multispheres and Earth SystemKey Laboratory of Physical OceanographyOcean University of ChinaQingdao 266000China

Besides the rapid retreating trend of Arctic sea-ice extent(SIE),this study found the most outstanding low-frequency variation of SIE to be a 4.6-year periodic *** a clustering analysis algorithm,the SIE in most ice-covered regions was clustered into two special regions:Region-1 around the Barents Sea and Region-2 around the Canadian Basin,which were located on either side of the Arctic Transpolar *** 4.6-year periodic variation in these two regions was identified using a novel method called“running linear fitting algorithm”.The rate of temporal variation of the Arctic SIE was related to three driving factors:the regional air temperature,the sea-ice areal flux across the Arctic Transpolar Drift,and the divergence of sea-ice *** 4.6-year periodic variation was found to have always been present since 1979,but the SIE responded to different factors under heavy and light ice conditions divided by the year *** joint contribution of the three factors to SIE variation exceeded 83%and 59%in the two regions,respectively,remarkably reflecting their dynamic *** is proven that the process of El Niño-Southern Oscillation(ENSO)is closely associated with the three factors,being the fundamental source of the 4.6-year periodic variations of Arctic SIE.

关键词： sea-ice extent periodic variation air temperature sea-ice areal flux Arctic Transpolar Drift ice-drift divergence ENSO