检索结果-南通市图书馆

Regulating melting Process in the Energy Storage of Solid-Liquid Pcm based on Double mRT-LBm Simulation

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 Thermal Science 2024年第5期33卷 1688-1700页

作者： cheN Weiqi SONG Zhichao QUAN Dongliang he Yurong School of Energy Science&Engineering Harbin Institute of TechnologyHarbin 150001China heilongjiang Key Laboratory of New Energy Storage materials and Processes Harbin 150001China Zhengzhou Research Institute of Harbin Institute of Technology Zhengzhou 450000China Innovation&Research Institute of Hiwing Technology Academy Beijing 100074China

The melting process of solid-liquid phase change materials(Pcm)has a significant impact on their energy storage *** more effectively apply solid-liquid Pcm for energy storage,it is crucial to study the regulation of melting process of solid-liquid Pcm,which is numerically investigated based on double multiple relaxation time lattice Boltzmann method(mRT-LBm)in this *** this work we pay more attention to the effects of different Stefan numbers(Ste)and Rayleigh numbers(Ra)on the melting *** results indicate that the Pcm melting is greatly influenced by the Ste number and Ra number,which can be divided into the heat conduction dominant stage and the convection dominant stage,according to the onset time of convection Fo_(c).In order to describe the contribution of the heat conduction dominant stage to the whole melting process quantitatively,we firstly propose the ratio of the heat conduction dominant stage R_(pc),which can be defined as the ratio of Fo_(c)to the complete melting time Fo_(m).R_(pc)gradually decreases as the Ra number increases,and when the Ste number rises:R_(pc)=90.0%when Ste=1.0 and Ra=1×10^(5),R_(pc)=39.6%when Ste=0.1 and Ra=1×10^(5),and R_(pc)=14.0%when Ste=1.0 and Ra=1×10~7.A regime map about the effects of different Ste numbers and Ra numbers on R_(pc)has been further *** discovered findings would be helpful in regulating melting process in the energy storage of solid-liquid Pcm.

关键词： latent thermal energy storage solid-liquid phase change double mRT-LBm dominant melting mechanism

Gravitational wave footprints from Higgs-portal scalegenesis with multiple dark chiral scalars

在线全文

学校读者我要写书评

暂无评论

chinese Physics c 2024年第4期48卷 209-221页

作者： he-Xu Zhang Shinya matsuzaki Hiroyuki Ishida center for Theoretical Physics and college of Physics Jilin UniversityChangchun 130012China center for Liberal Arts and Sciences Toyama Prefectural UniversityToyama 939-0398Japan

We discuss the gravitational wave(GW)spectra predicted from the electroweak scalegenesis of the Higgs portal type with a large number of dark chiral flavors,which many flavor QcD would underlie and give the dynamical explanation of the negative Higgs portal coupling required to trigger the electroweak symmetry *** employ the linear-sigma model as the low-energy description of dark many flavor QcD and show that the model undergoes ultra-supercooling due to the produced strong first-order thermal phase transition along the(approximately realized)flat direction based on the Gildener-Weinberg *** through evaluation of the bubble nucleation/percolation,we address the reheating and relaxation processes,which are generically non-thermal and *** the reheating epoch in terms of the e-folding number,we propose proper formulae for the redshift effects on the GW frequencies and signal *** then turns out that the ultra-supercooling predicted from the Higgs-portal scalegenesis generically yields none of GW signals with the frequencies as low as nano Hz,unless the released latent heat is transported into another sector other than reheating the ***,models of this class prefer to give the higher frequency signals and still keeps the future prospected detection sensitivity,like at LISA,BBO,and DEcIGO,*** also find that with large flavors in the dark sector,the GW signals are made further smaller and the peak frequencies *** phenomenological consequences related to the multiple chiral scalars include the prediction of dark pions with the mass much less than TeV scale,which is also briefly addressed.

关键词： gravitational wave electroweak scalegenesis many flavor QcD

carbon allocation in Picea jezoensis:Adaptation strategies of a non-treeline species at its upper elevation limit

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 2024年第3期11卷 347-357页

作者： Renkai Dong Na Li mai-he Li Yu cong Haibo Du Decai Gao Hong S.he Key Laboratory of Geographical Processes and Ecological Security in changbai mountains Ministry of EducationSchool of Geographical SciencesNortheast Normal UniversityChangchun130024China School of Natural Resources University of MissouriColumbiaMO65211USA Swiss Federal Institute for Forest Snow and Landscape Research WSL8903BirmensdorfSwitzerland Northeast Institute of Geography and Agricultural Ecology Chinese Academy of SciencesChangchun130102China School of Life Science Hebei UniversityBaoding071002China

Understanding the physiological adaptations of non-treeline trees to environmental stress is important to understand future shifts in species composition and distribution of current treeline *** aim of the present study was to elucidate the mechanisms of the formation of the upper elevation limit of non-treeline tree species,Picea jezoensis,and the carbon allocation strategies of the species on changbai *** employed the^(13)c in situ pulse labeling technique to trace the distribution of photosynthetically assimilated carbon in Picea jezoensis at different elevational positions(tree species at its upper elevation limit(TSAUE,1,700 m a.s.l.)under treeline ecotone;tree species at a lower elevation position(TSALE,1,400 m a.s.l.).We analyzed^(13)c and the non-structural carbohydrate(NSc)concentrations in various tissues following *** findings revealed a significant shift in carbon allocation in TSAUE compared to *** was a pronounced increase inδ^(13)c allocation to belowground components(roots,soil,soil respiration)in TSAUE compared to ***,the c flow rate within the plant-soil-atmosphere system was faster,and the c residence time in the plant was shorter in *** trends indicate enhanced c sink activity in belowground tissues in TSAUE,with newly assimilated c being preferentially directed there,suggesting a more conservative c allocation strategy by *** at higher elevations under harsher *** a strategy,prioritizing c storage in roots,likely aids in withstanding winter cold stress at the expense of aboveground growth during the growing season,leading to reduced growth of TSAUE compared to *** results of the present study shed light on the adaptive mechanisms governing the upper elevation limits of non-treeline trees,and enhances our understanding of how non-treeline species might respond to ongoing climate change.

关键词： ^(13)c pulse labeling carbon distribution Non-structural carbohydrates(NSc) Non-treeline species Sink activity Stressful environments Upper elevation limit

Performance of evolutionary optimized machine learning for modeling total organic carbon in core samples of shale gas fields

在线全文

学校读者我要写书评

暂无评论

Petroleum 2024年第1期10卷 150-164页

作者： Leonardo Goliatt c.m.Saporetti L.c.Oliveira E.Pereira Department of computational and Applied mechanics Federal University of Juiz de ForaJuiz de ForaBrazil Department of computational modeling Polytechnic InstituteRio de Janeiro State UniversityNova FriburgoBrazil Petrobras Rio de JaneiroBrazil Department of Stratigraphy and Paleontology Rio de Janeiro State UniversityRio de JaneiroBrazil

Rock samples'TOc content is the best indicator of the organic matter in source *** origin rock samples’analysis is used to calculate it manually by *** method requires time and resources because it relies on samples from many well intervals in source ***,research has been done to aid this *** learning algorithms can estimate total organic carbon instead of well logs and stratigraphic *** light of these efforts,the current work present a study on automating the total organic carbon estimation using machine learning approaches improved by an evolutionary methodology to give the model flexibility and *** algorithms,differential evolution,particle swarm optimization,grey wolf optimization,artificial bee colony,and evolution strategies were used to improve machine learning models to predict *** six metaheuristics were integrated into four machine learning methods:extreme learning machine,elastic net linear model,linear support vector regression,and multivariate adaptive regression *** samples from the YuDong-Nan shale gas field,located in the Sichuan basin,were used to evaluate the hybrid *** findings show that combining machine learning models with an evolutionary algorithms in a hybrid fashion produce flexible models that accurately predict *** results show that,independent of the metaheuristic used to guide the model selection,optimized extreme learning machines attained the best performance scores according to six *** hybrid models can be used in exploratory geological research,particularly for unconventional oil and gas resources.

关键词： Total organic carbon Hybrid models Automated machine learning Evolutionary algorithms Geology

Identification of the optimal doping position of hetero-atoms in chalcogen-doped Fe-N-c catalysts for oxygen reduction reaction

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第6期89卷 99-108页

作者： Weihao Liu Huanhuan he Qingtao Liu Xin Wan Jianglan Shui School of materials Science and Engineering Beihang UniversityBeijing100191China School of Space and Environment Beihang UniversityBeijing102206China Tianmushan Laboratory Hangzhou310023China

The excellent oxygen reduction reaction(ORR)activity of Fe–N–c catalysts in acidic media makes them potential for low-cost proton exchange membrane fuel *** recent years,it has been shown that heteroatoms(B,O,S,P,cl,F,etc.)can be used as electron-withdrawing groups to modulate the planar structure and electron distribution of the Fe–Nx active sites to achieve simultaneous improvement of catalytic activity and ***,the optimal location of the heteroatoms remains ***,taking chalcogen heteroatoms(S and Se)as an example,we control the doping positions and investigate their effect on the ORR performance of the Fe–N–c *** first coordination shell of the iron single atom is identified as the optimal doping *** optimized catalysts Fe–N_(3)Se_(1)/Nc and Fe–N_(3)Se_(1)/Nc demonstrate improved activity and stability in both half cells and fuel *** work provides insights into the enhancement mechanism of heteroatom doping in single-atom catalysts.

关键词： Oxygen reduction reaction Fe-N-c catalysts hetero-atom doping Doping position Enhancement mechanism

Underwater four-quadrant dual-beam circumferential scanning laser fuze using nonlinear adaptive backscatter filter based on pauseable SAF-LmS algorithm

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第7期37卷 1-13页

作者： Guangbo Xu Bingting Zha Hailu Yuan Zhen Zheng he Zhang ministerial Key Laboratory of ZNDY Nanjing University of Science and TechnologyNanjing 210094China Science and Technology on Electromechanical Dynamic control Laboratory Beijing 100081China Shanghai Radio Equipment Research Institute Shanghai 201109China

The phenomenon of a target echo peak overlapping with the backscattered echo peak significantly undermines the detection range and precision of underwater laser *** overcome this issue,we propose a four-quadrant dual-beam circumferential scanning laser fuze to distinguish various interference signals and provide more real-time data for the backscatter filtering *** enhances the algorithm loading capability of the *** order to address the problem of insufficient filtering capacity in existing linear backscatter filtering algorithms,we develop a nonlinear backscattering adaptive filter based on the spline adaptive filter least mean square(SAF-LmS)*** also designed an algorithm pause module to retain the original trend of the target echo peak,improving the time discrimination accuracy and anti-interference capability of the ***,experiments are conducted with varying signal-to-noise ratios of the original underwater target echo *** experimental results show that the average signal-to-noise ratio before and after filtering can be improved by more than31 d B,with an increase of up to 76%in extreme detection distance.

关键词： Laser fuze Underwater laser detection Backscatter adaptive filter Spline least mean square algorithm Nonlinear filtering algorithm

characterization of Fe-containing particles in chengdu,southwest china,using single-particle aerosol mass spectrometry

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第2期136卷 110-120页

作者： Renjiang he Junke Zhang Luyao chen Wei Zhang Yingwei Xi School of Public health Southwest Medical UniversityLuzhou 646000China Faculty of Geosciences and Environmental Engineering Southwest Jiaotong UniversityChengdu 611756China Sichuan Environmental monitoring center Chengdu 610074China

Single-particle aerosol mass spectrometry was used to study the characteristics of Fecontaining particles during winter in chengdu,southwest *** mass concentrations of Pm_(2.5)and Pm_(10)during the study period were 64±38 and 89±49μg/m~3,respectively,and NO_(2)and particulate matter were high compared with most other regions of *** Fecontaining particles were divided into seven categories with different mass spectra,sources and aging *** highest contribution was from Fe mixed with carbonaceous components(Fe-c,23.1%)*** was more mixed with sulfate than nitrate and therefore the contribution of Fe mixed with sulfate(Fe-S,20.7%)particles was higher than that of Fe mixed with nitrate(Fe-N,12.5%)*** contributions from Fe-containing particles related to primary combustion were high in the small particle size range,whereas aged Fecontaining particles and dust-related particles were mostly found in the coarse particle size *** air masses mainly originated from the west and east of chengdu,and the corresponding Pm_(2.5)concentrations were 79±36 and 55±36μg/m~3,*** west and east air masses showed stronger contributions of Fe-containing particles related to biomass burning(Fe-B)and fossil fuel combustion(Fe-c and Fe-S)particles,*** southwest area contributed the most Fe-containing *** assessments of the effects of Fe-containing particles during heavy pollution period should pay more attention to Fe-c and Fe-S ***-reduction of Fe-containing particles should consider both local emissions and short-distance transmission from the surrounding areas.

关键词： Fe-containing particles Particle composition Potential source areas Evolution chengdu

Highly Strong,Tough,and cryogenically Adaptive Hydrogel Ionic conductors via coordination Interactions

在线全文

学校读者我要写书评

暂无评论

Research 2024年第3期2024卷 703-713页

作者： Zhuomin Wang Siheng Wang Lei Zhang he Liu Xu Xu Institute of chemical Industry of Forestry Products Key Laboratory of Biomass Energy and MaterialJiangsu ProvinceKey Laboratory of Chemical Engineering of Forest ProductsNational Forestry and Grassland AdministrationNational Engineering Research Center of Low-Carbon Processing and Utilization of Forest BiomassJiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest ResourcesChinese Academy of ForestryNanjing 210042China college of chemical Engineering Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest ResourcesNanjing Forestry UniversityNanjing 210037China.

Despite the promise of high flexibility and conformability of hydrogel ionic conductors,existing polymeric conductive hydrogels have long suffered from compromises in mechanical,electrical,and cryoadaptive properties due to monotonous functional improvement strategies,leading to lingering ***,we propose an all-in-one strategy for the preparation of poly(acrylic acid)/cellulose(PAA/cel)hydrogel ionic conductors in a facile yet effective manner combining acrylic acid and salt-dissolved cellulose,in which abundant zinc ions simultaneously form strong coordination interactions with the two polymers,while free solute salts contribute to ionic conductivity and bind water molecules to prevent ***,the developed PAA/cel hydrogel simultaneously achieved excellent mechanical,conductive,and cryogenically adaptive properties,with performances of 42.5 mPa for compressive strength,1.6 mPa for tensile strength,896.9%for stretchability,9.2 mJ m^(−3)for toughness,59.5 kJ m^(−2)for fracture energy,and 13.9 and 6.2 mS cm^(−1)for ionic conductivity at 25 and−70°c,*** by these features,the resultant hydrogel ionic conductor is further demonstrated to be assembled as a self-powered electronic skin(e-skin)with high signal-to-noise ratio for use in monitoring movement and physiological signals regardless of cold temperatures,with hinting that could go beyond high-performance hydrogel ionic conductors.

关键词： Highly freezing salts

Impact of cOVID-19-related lifestyle changes on diabetic macular edema

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 Ophthalmology(English edition) 2024年第1期17卷 97-106页

作者： Bryce P.Johnson Yu-Guang he Zachary m.Robertson Angeline Wang Rafael L.Ufret-Vincenty Department of Ophthalmology UT Southwestern Medical CenterDallasTexas 75390-9057USA

AIm:To assess diabetic macular edema(DmE)progression during the early phases of the cOVID-19 pandemic,when severe societal restrictions raised the concern of possible deterioration of health in patients with systemic conditions,particularly those requiring frequent office ***:This is a multicenter retrospective chart review of 370 patients(724 eyes)with an established diagnosis of DmE seen on 3 separate visits between January 2019 and July *** 1 was January 2019 to February 2020(considered pre-cOVID-19),period 2 was march 2020 to December 2020(considered the height of the pandemic;highest level of pandemic-related clinical and societal regulations)and period 3 was January 2021 to July 2021(re-adjustment to the new“pandemic norms”).main outcome measures included visual acuity,body mass index(BmI),blood pressure(BP),hemoglobin A1c(HbA1c),macular thickness,patient adherence to scheduled ophthalmology visits,and DmE treatment(s)received at each *** facilitate measurement of macular thickness,each macula was divided into 9 Early Treatment Diabetic Retinopathy Study(ETDRS)-defined macular sectors as measured by OcT ***:There was no change of BmI,systolic BP,and diastolic BP between any of the time ***1c showed a very small increase from period 1(7.6%)to period 2(7.8%,P=0.015)and decreased back to 7.6%at period 3(P=0.12).macular thickness decreased for 100%of macular *** central macular thickness decreased across all 3 periods from 329.5 to 316.6μm(P=0.0045).After analysis of multiple variables including HbA1c,BmI,adherence to scheduled appointments,different clinic centers,and treatment interventions,there was no easily identifiable subgroup of patients that experienced the increase in ***:DmE doesn’t worsen during the cOVID-19 pandemic,instead sustaining a very small but statistically significant *** identifying a mechanism behind our findings is beyond the scope of this study,potential explanat

关键词： cOVID-19 diabetic macular edema diabetic retinopathy optical coherence tomography