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Effect of brazing parameters on fillet size and microstructure of cladded fin-microchannel tube joints

Transactions of Nonferrous Metals Society of china 2020年第12期30卷 3240-3253页

作者： j.c.guía-tello M.I.PEcH-cANUL E.TRUjILLO-VÁZQUEZ M.A.PEcH-cANUL centro de investigación en materiales avanzados(cimav) laboratorio nacional de nanotecnologíamiguel de cervantes no.120chihuahuachi8.31136méxico centro de investigación y de estudios avanzados del instituto politécnico nacional-unidad saltillo av.industria metalúrgica no.1062parque industrial saltillo-ramos arizperamos arizpecoahuila25900méxico conacyt-facultad de ciencias físico matemáticas benemérita universidad autónoma de pueblaav.san claudiocd universitariajardines de san manuelpueblapuebla72570méxico cinvestav-mérida km 6 ant.carr.a progresoap 73 cordemexméridayu3.97310méxico

This work concerns the optimization of furnace brazing conditions for joining micro-multiport aluminum tubes and fins made with AA4343/AA3003/AA4343 brazing sheet in mini-assemblies mimicking the core of an automotive heat *** method was used for design of experiment,considering five process parameters with two levels of *** aim was to maximize the fillet size of the brazed joints,which has an important influence on the thermal integrity and mechanical *** length measurements of brazed joints were performed with a metallographic *** statistical analysis allowed to obtain the optimum values of process parameters(peak temperature,residence time,heating rate,microchannel tube type and flux).At a 95%confidence level,the variability of fillet length is most significantly affected by the peak brazing temperature(77%),residence time(15%)and heating rate(7%).The predicted maximum fillet length was(152±11)μm,which was corroborated by confirmation *** microstructural analysis of tube−fin joints showed that variations in peak temperature and residence time affect only the size of the eutectic zone of fillet formed,but not the nature or composition of the constituent phases.

关键词： brazing cladded fin Taguchi method fillet size microstructure aluminum peak temperature optimization

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Distinct Effects of Three Tea Varieties Made Green Teas on Improving Diabetic Dyslipidemia Induced by High-Fat Diet in c57BL/6j Mice

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Food Science and Human Wellness 2024年

作者： Wei gu Zhutong Wang guohuo Wu Huimin guo Huijun cheng cong Li Linbo chen Daxiang Li Zhongwen Xie State Key Laboratory of Tea Plant Biology and Utilization， School of Tea and Food Sciences & Technology， Anhui Agricultural University center for Biotechnology， Anhui Agricultural University college of Life Sciences， Anhui Agricultural University Tea Research Institute， Yunnan Academy of Agricultural Sciences

currently， cultivated tea plants are classified into three varieties， namely， c. sinensis var. sinensis， c. sinensis var. assamica， and c. sinensis var. kucha. Three tea varieties made green teas (TVGTs) are widely consumed worldwide. However， a comparative investigation of the beneficial effects， mechanism， and characteristic compounds of TVGTs has not been reported. Here， three representative tea plant varieties， namely， c. sinensis var. sinensis cv. Fuding (FD)， c. sinensis var. assamica cv. Yunkang 10 (YK)， and c. sinensis var. kucha (Kc)， planted in the same garden， were used to make green teas utilizing the same standard procedure. Our findings show that the TVGTs effectively improved hyperglycemia， obesity， dyslipidemia， fatty liver， and mesenteric artery (MA) hypercontractility in mice with diabetes and obesity induced by a high-fat diet (HFD) after 11- and 22-week interventions， with YK being the most effective at 22 weeks. Liver lipidomics indicated that the TVGTs restored the glycerophospholipid and sphingolipid balance and reduced triglycerides， with YK demonstrating superior effects. The TVGTs， particularly YK， suppressed triglyceride synthesis through the ARV1-FXR-SHP-SREBP-1c pathway. A chemical profile analysis revealed that YK green tea had enriched active compounds， including caffeine， quinic acid， L-theanine， gallic acid， and catechins， compared with FD and Kc green teas， which may contribute to ameliorating diabetic dyslipidemia via synergistic action. As a representative tea variety of c. sinensis var. assamica， YK green tea was found to be superior to the other two green teas in preventing and treating diabetic dyslipidemia， especially with long-term consumption. These data provide important information for tea plant breeders and tea consumers.

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Taxonomic dependency and spatial heterogeneity in assembly mechanisms of bacteria across complex coastal waters

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Ecological Processes 2024年第1期13卷 80-97页

作者： Huizhen Yan Dandan Lin Gaoke gu Yujie Huang Xuya Hu Zhenhao Yu Dandi Hou Demin Zhang Barbara j.campbell Kai Wang State Key Laboratory for Managing Biotic and chemical Threats to the Quality and Safety of Agro-Products School of Marine SciencesNingbo University Key Laboratory of Marine Biotechnology of Zhejiang Province School of Marine Sciences Ningbo University Department of Biological Sciences Clemson University

Background Understanding community assembly mechanisms across taxa and space is fundamental for microbial ecology. However, the variability and determinants of assembly processes over taxa and space remain unclear. Here, we investigated taxonomic dependency and spatial heterogeneity in bacterial assembly mechanisms across coastal waters in the East china Sea using neutral and null models with customized visualization *** Overall, bacterial assembly mechanisms varied across broad taxonomic groups(phyla and proteobacterial classes) and space at the regional scale. A determinism–stochasticity balanced mechanism governed total bacterial assembly, while taxonomic dependency existed in assembly mechanisms and ecological processes. Among community ecological features, niche breadth and negative-to-positive cohesion ratio were strongly associated with the determinism-to-stochasticity ratio of bacterial groups. Bacterial assembly mechanisms commonly exhibited spatial heterogeneity, the extent and determinants of which varied across taxonomic groups. Spatial assembly of total bacteria was directly driven by many environmental factors and potential interactions between taxa, but not directly by geographic factors. Overall, the bacterial groups with higher spatial heterogeneity in assembly mechanisms were more related to environmental and/or geographic factors(except Bacteroidetes), while those with lower heterogeneity were more related to ecological *** Our results confirm the pervasiveness of taxonomic dependency and spatial heterogeneity in bacterial assembly, providing a finer understanding about regulation across complex coastal waters.

关键词： Bacterioplankton Assembly mechanism Niche breadth Null model Environmental gradient Biogeography

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consumer transparency in the production chain for plant varieties produced using new genomic techniques

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aBIOTEcH 2024年第2期5卷 239-246页

作者： j.M.Lukasiewicz c.c.M.van de Wiel L.A.P.Lotz M.j.M.Smulders Wageningen University&Research P.O.Box 386NL-6700 AJ WageningenThe Netherlands

Plants edited with new genomic techniques(NGTs)currently fall under the Genetically Modified Organisms Directive(2001/18/Ec)in the European *** the proposal of the European commission,NGT plants are partially exempted from the regulations of this *** proposal makes a distinction between two categories of NGT plants:NGT-1 and ***-1 category plants are considered equal to plants obtained through conventional breeding *** plants will not be labelled for the consumer,although they will be labelled as ***-2 category plants may be labelled with additional information as a positive *** of seeds of varieties made with gene editing,but not the products,would mean that most steps in the production chain are transparent,but not the last step towards ***“right to know”and increasing knowledge of gene-edited food is a common theme in food labelling towards ***,we describe current labelling regimes and registers and how these may be applied to provide transparency on gene-edited products to ***,we also look into consumer studies,which indicate a greater acceptance of gene-edited food among consumers,especially when additional benefits such as sustainability are mentioned.

关键词： Labelling New genomic techniques consumer transparency Plant products

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Tuning electronic properties of cobalt phthalocyanines for oxygen reduction and evolution reactions

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Science china chemistry 2024年第1期67卷 398-407页

作者： jianlin jiang Zhen Liu Shuaijun Pan Xinnian Xia Bing Qin Yang Hu Xuxu Wang jiamin Lan Yu gu Encai Ou Weijian Xu joseph j.Richardson Rui guo SINOPEc Research Institute of Petroleum Processing co. Ltd.Beijing 100083China college of chemistry and chemical Engineering Hunan UniversityChangsha 410082China college of chemistry and Materials Science Hunan Agricultural UniversityChangsha 410128China Department of chemical Engineering The University of MelbourneParkville 3010Australia college of Environmental Science and Engineering Hunan UniversityChangsha 410082China School of Engineering RMIT UniversityMelbourneVictoria 3001Australia

Metal–phthalocyanines are a class of catalytically active materials promising in energy conversion and storage fields(e.g.,electrocatalysis).However,understanding and controlling the electrochemical properties in metal-phthalocyanine systems is ***,we elucidate the electrocatalytic origins of a series of cobalt-phthalocyanine molecular catalysts and finetune their electronic properties at the atomic level,both experimentally and *** interactions between the cobalt center and the local coordination environment are regulated by introducing either electron-donating or electron-withdrawing groups on the phthalocyanine ligand,and the spin-orbit splitting of cobalt is increased by~0.15 eV compared with the nonsubstituted ***,the aminated cobalt phthalocyanine-based electrocatalysts exhibit low free energies in the ratedetermining steps of the oxygen reduction(-1.68 eV)and oxygen evolution reactions(0.37 eV).This contributes to the high electrocatalytic activity(e.g.,a halfwave potential of 0.84 V and an overpotential of 0.30 V at 10 mAcm^(-2)),featuring a high selectivity of a four-electron pathway(i.e.,a negligible by-product of hydrogen peroxide).These catalysts also exhibit exceptional kinetic current density(Tafel slope of 100 mV dec^(-1))in oxygen reduction reactions,in addition to a superior power density(158 mWcm^(-2))and a high cycling stability(>1,300 cycles)in Zn-air batteries,outperforming the commercial Pt/c and/or RuO2counterparts.

关键词： interfacial wettability molecular catalysts carbon nanotubes density functional theory electrochemistry

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Semi-analytical investigation of heat transfer in a porous convective radiative moving longitudinal fin exposed to magnetic field in the presence of a shape-dependent trihybrid nanofluid

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Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 197-216页

作者： c.G.PAVITHRA B.j.GIREESHA M.L.KEERTHI Department of PG Studies and Research in Mathematics Kuvempu UniversityShankaraghatta 577451India Department of Mathematics and Statistics M.S.Ramaiah University of Applied SciencesBengaluru 560058India

The thermal examination of a non-integer-ordered mobile fin with a magnetism in the presence of a trihybrid nanofluid(Fe_3O_4-Au-Zn-blood) is carried out. Three types of nanoparticles, each having a different shape, are considered. These shapes include spherical(Fe_3O_4), cylindrical(Au), and platelet(Zn) configurations. The combination approach is utilized to evaluate the physical and thermal characteristics of the trihybrid and hybrid nanofluids, excluding the thermal conductivity and dynamic viscosity. These two properties are inferred by means of the interpolation method based on the volume fraction of nanoparticles. The governing equation is transformed into a dimensionless form, and the Adomian decomposition Sumudu transform method(ADSTM) is adopted to solve the conundrum of a moving fin immersed in a trihybrid nanofluid. The obtained results agree well with those numerical simulation results, indicating that this research is reliable. The influence of diverse factors on the thermal overview for varying noninteger values of γ is analyzed and presented in graphical representations. Furthermore, the fluctuations in the heat transfer concerning the pertinent parameters are studied. The results show that the heat flux in the presence of the combination of spherical, cylindrical, and platelet nanoparticles is higher than that in the presence of the combination of only spherical and cylindrical nanoparticles. The temperature at the fin tip increases by 0.705 759% when the value of the Peclet number increases by 400%, while decreases by 11.825 13% when the value of the Hartman number increases by 400%.

关键词： convection radiation moving longitudinal fin Adomian decomposition Sumudu transform method(ADSTM) trihybrid nanofluid magnetic field

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Thermoluminescence characterization of natural and synthetic irradiated ce-monazites

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journal of Rare Earths 2024年第4期42卷 643-650页

作者： V.correcher c.Boronat j.Garcia-guinea j.F.Benavente T.Rivera-Montalvo cIEMAT Av.Complutense 4028040MadridSpain MNcN-cSIc J.Gutierrez Abascal 228006MadridSpain Instituto Politécnico Nacional CICATA-IPNAv.Legaria 694Mexico City11500Mexico

The thermoluminescence(TL)emission of synthetic and natural ce-monazites was characterized here to determine the potential application in the identification of microscopic defects from a qualitative point of view trying to link each TL peak to a chemical-physical *** kinetic parameters that lead the luminescence processes were calculated by means of variable heating rate and computing glow curve deconvolution methods and allow identifying three groups of components at~90,130 and 290℃(for the mineral sample)and~90,170,220,270 and 320℃(for the synthetic cePO_(4):Nd_(0.20),La_(0.25)).The main differences appreciated in these complex TL curves are mainly due to(i)the content of impurities(natural sample contains lanthanides as well as U 0.60%and Th 5.22%)and(ii)the degree of crystallinity of the samples which is directly related to the type of impurities(synthetic monazite relies only on Nd and La).The behavior of the dose response in the range of 1-8 Gy is similar for both samples;the TL intensity increases linearly as the dose increases without changes in the position of the maxima,denoting first-order kinetic luminescence *** peak could be mostly associated with structural defects(i.e.,phase transitions),chemical reactions(i.e.,ce3+?ce4+redox reaction,dehydration or dehydroxylation processes)or intrinsic defects(i.e.,Frenkel defects,ODcs or NBOHcs).

关键词： Thermoluminescence Kineticparameters Phosphate ce-monazite Defects Rare earths

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A marathon,not a sprint:Increasing population physical activity as a legacy of sports mega-events

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journal of Sport and Health Science 2024年第6期13卷 732-735页

作者： Fiona c.Bull Paul j.Simpson Physical Activity Unit Department of Health PromotionWorld Health OrganizationGeneva CH-1211Switzerland The BMj London WC1H 9JPUK

*** matters The withdrawal of Australia as hosts for the commonwealth Games in 2026 demonstrates that large international sporting events are more than just sporting mastery,medals,and *** also matters.1 The cost of hosting a major international tournament is eye-wateringly *** governments need to show that the billions of dollars of investment deliver a return beyond sporting glory to justify the resources that are spent.

关键词： return dollar sport

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cO oxidation under lean and stoichiometric conditions over ceriazirconia with very low metal contents(cu,co,Ag and Pt)

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journal of Rare Earths 2024年第9期42卷 1669-1681,I0002页

作者： j.c.Martínez-Munuera M.P.Yeste A.García-García McMA Group Department of Inorganic Chemistry and Institute of MaterialsUniversity of AlicanteCarretera de San Vicente del Raspeig s/n03690San Vicente del RaspeigAlicanteSpain Solid chemistry and catalysis Group Department of Materials ScienceMetallurgic Engineering and Inorganic ChemistryInstitute of Electronic Microscopy and Materials ResearchUniversity of CádizAp.40E-11510Puerto RealCádizSpain

In this work,several ceria-zirconia based catalysts with very lo w(and equimolar) metal contents were prepared,characterised and tested for the cO oxidatio n reaction(under lean and stoichiometric conditions),trying to emulate those conditions found in a diesel oxidation catalyst(DOc) system from a diesel engine and those encountered under gasoline exhaust(λ=1).The metals chosen are cu,co,Ag and Pt(as a reliable benchmark).The results reveal enormous differences among reducibility and catalytic activity despite quite similar structural and textural properties of the catalysts,showing differences among dispersion(Ag-catalyst seems to present a low level of dispersion).This catalyst seems to be characterised,as well,by a strong electronic interaction between ce and Ag centres which is suggested to yield an improved reducibility under H_(2)-TPR ***,the order in catalytic activity(cu>Ag>co≈Pt>>support) seems not to follow the order found in reducibility and the cu-catalyst seems to be the most active independently on the reaction conditions,yielding nearly overlapped cO oxidation catalytic *** restingly,a stro ng correlation between the catalytic activity under the two conditions tested and the OSc values of the ce_(0.8)Zr_(0.2)O_(2)-supported metal catalysts is ***,OSc parameter measured at 150℃ can be used as a relevant descriptor to evaluate the cO oxidation activity at low and medium conversions for the investigated catalysts,much better than the H_(2)-TPR measurements.

关键词： cO oxidation Low metal content ceria-zirconia copper species OSc parameter Rare earths

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The challenging management of malignant ureteral obstruction:Analysis of a series of 188 cases

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current Urology 2024年第1期18卷 34-42页

作者： Alberto Artiles Medina Inés Laso García Fernando González tello Sara Álvarez Rodríguez Manuel Hevia Palacios Marina Mata Alcaraz césar Mínguez Ojeda Fernando Arias Funez Victoria Gómez Dos Santos Francisco javier Burgos Revilla Department of Urology Hospital Universitario Ramón y CajalMadridSpain Department of Radiology Hospital Universitario Ramón y CajalMadridSpain

Background:Malignant ureteral obstruction(MUO)is a common condition that complicates the course of advanced *** aims of this study are to analyze the causes,management,and survival of patients with obstructive nephropathy due to malignant ureteric obstruction and to determine prognostic ***,we studied the complications and outcomes in patients who underwent urinary *** and methods:A retrospective study was conducted on patients with computed tomography-confirmed MUO between january 2016 and November ***,clinical,radiological,laboratory,and management data were *** curves were estimated using the Kaplan-Meier method,and univariate and multivariate cox proportional hazards models were used to test the association between parameters and ***:A total of 188 patients were *** mean age was 69.01 years(SD,14.95 years),and the majority(54.8%)were *** most common mechanism leading to MUO was compression by a pelvic mass(36.9%),and the 3 most frequent tumors causing MUO were prostate(17.6%),bladder(16.5%),and rectal cancer(11.7%).Forty-seven patients(25%)underwent urinary diversion:23(48.9%)underwent double-j stenting and 21(44.7%)underwent percutaneous *** most common reason for urinary diversion was acute kidney injury(53.3%).Recovery of renal function was observed in 55.8%of the patients after urinary *** most frequently identified complications after urinary diversion were urinary tract infection(24.4%),hematuria(17.0%),and urinary sepsis(14.9%).The median survival after hydronephrosis diagnosis was 6.43 months(interquartile range,1.91-14.81 months).In patients who underwent urinary decompression,the median survival after urinary diversion was 8.67 months(interquartile range,2.99-17.28 months).In the multivariate analysis,a lower grade of hydronephrosis and cancer cachexia negatively impacted ***:cancer patients with MUO have a poor pro

关键词： Hydronephrosis Ureteral obstruction Neoplasms Urinary diversion Survival Prognosis

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