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Friction 2024年第3期12卷 522-538页

作者： Marta OsTOLAZA Alaitz ZABALA Jon inaki ARRiZUBiETA iñigo LLAVORi Nagore OTEGi Aitzol LAMiKiZ Department of Mechanical Engineering University of the Basque Country UPV/EHUPlaza Torres Quevedo 1Bilbo 48013Spain Faculty of Engineering Mechanics and Industrial ProductionMondragon UnibertsitateaLoramendi 4Mondragon 20500Spain

Wear-driven tool failure is one of the main hurdles in the *** issue can be addressed through surface coating with ceramic-reinforced metal matrix ***,the maximum ceramic content is limited by *** this work,the tribological behaviour of the functionally graded WC-ceramic-particlereinforced stellite 6 coatings is *** that end,the wear resistance at room temperature and 400°C is ***,the tribological analysis is supported by crack sensitivity and hardness evaluation,which is of utmost importance in the processing of composite materials with *** indicate that functionally graded materials can be employed to increase the maximum admissible WC content,hence improving the tribological behaviour,most notably at high ***,a shift from abrasive to oxidative wear is observed in high-temperature wear testing.

关键词： friction coating metal matrix composite functionally graded materials high temperature laserdirected energy deposition

Tailoring local structures of atomically dispersed copper sites for highly selective CO_(2) electroreduction

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Carbon Energy 2024年第4期6卷 79-90页

作者： Kyung‐Jong Noh Byoung Joon Park Ying Wang Yejung choi sang‐Hoon You Yong‐Tae Kim Kug‐seung Lee Jeong Woo Han Department of Chemical Engineering Pohang University of Science and Technology(POSTECH)PohangGyeongbukRepublic of Korea Department of Materials science and Engineering Pohang University of Science and Technology(POSTECH)PohangGyeongbukRepublic of Korea Pohang Accelerator Laboratory(PAL) Beamline DivisionPohangGyeongbukRepublic of Korea

Atomically‐dispersed copper sites coordinated with nitrogen‐doped carbon(Cu–N–C)can provide novel possibilities to enable highly selective and active electrochemical CO_(2) reduction ***,the construction of optimal local electronic structures for nitrogen‐coordinated Cu sites(Cu–N_(4))on carbon remains ***,we synthesized the Cu–N–C catalysts with atomically‐dispersed edge‐hosted Cu–N_(4) sites(Cu–N_(4)C_(8))located in a micropore between two graphitic sheets via a facile method to control the concentration of metal ***‐hosted Cu–N_(4)C_(8) catalysts outperformed the previously reported M–N–C catalysts for CO_(2)‐to‐CO conversion,achieving a maximum CO Faradaic efficiency(FECO)of 96%,a CO current density of–8.97 mA cm^(–2) at–0.8 V versus reversible hydrogen electrode(RHE),and over FECO of 90%from–0.6 to–1.0 V versus *** studies revealed that the micropore of the graphitic layer in edge‐hosted Cu–N_(4)C_(8) sites causes the d‐orbital energy level of the Cu atom to shift upward,which in return decreases the occupancy of antibonding states in the*COOH *** research suggests new insights into tailoring the locally coordinated structure of the electrocatalyst at the atomic scale to achieve highly selective electrocatalytic reactions.

关键词： atomic local structure density functional theory electrochemical CO_(2)reduction metal nitrogen‐doped carbon single‐atom catalyst

The Adsorption Properties of TEMPO Oxidized Cellulose against the Mixture of Methylene Blue and Rhemazol Yellow FG

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Journal of Renewable Materials 2024年第8期12卷 1369-1382页

作者： Mahendra, i. Putu Dinita, Kartika Program studi Kimia Fakultas Sains Insitut Teknologi Sumatera Jalan Terusan Ryacudu Way Huwi Jati Agung Lampung Selatan 35365 Indonesia

TEMPO/NaOCl/NaBr treatment significantly increased the number of negative charges on the cellulose surface. Two concentrations of NaOCl, 5 and 30 mmol/g of cellulose, were used in this study. The number of carboxyl groups in the two cellulosic samples oxidized using TEMPO/NaOCl/NaBr was 0.5160 and 1.8461 mmol/g of cellulose, respectively. The oxidized cellulose samples treated with 5 and 30 mmol/g NaOCl exhibited higher crystallinity, at 81.15% and 80.14%, respectively, compared to untreated cellulose, which had a crystallinity of 75.95%. The pH effect indicated that the highest adsorption capacity for methylene blue was achieved under alkaline conditions (pH 9), while the highest adsorption capacity for rhemazol yellow FG was achieved under acidic conditions. The kinetic model of TEMPO-oxidized cellulose for methylene blue and rhemazol yellow FG conformed to the pseudo-second-order model. The initial concentration parameter revealed that the isotherm model for the adsorption of methylene blue and rhemazol yellow FG by TEMPO-oxidized cellulose conformed to the Langmuir model. The dye removal efficiencies for methylene blue and rhemazol yellow FG using TEMPO-oxidized cellulose (30 mmol/g) were approximately 80.17% and 59.52%, respectively. These results demonstrate that TEMPO/NaOCl/NaBr-oxidized samples can effectively separate cationic and anionic dye mixtures. Furthermore, the use of TEMPO-oxidized cellulose showed good regeneration capability, maintaining more than 95% of its adsorption capacity after 8 cycles. © 2024 The Authors.

关键词： stripping (dyes)

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计算超导螺线管磁体中电磁应力的解析方法

Acta Mechanica sinica 2024年第4期40卷 4-20页

作者： Jeonghwan Park Kibum choi Yufan Yan Jaemin Kim seungyong Hahn Department of Electrical and Computer Engineering Seoul National UniversitySeoul08826Republic of Korea Applied superconductivity Center and Electric Power institute Seoul National UniversitySeoul08826Republic of Korea

在高场磁体中,压缩磁径向应力比拉伸应力更受青睐,原因是它能降低磁体绕组内的整体峰值磁应力.这对于无绝缘高温超导(Ni HTs)磁体尤为重要,因为压缩径向应力能够产生良好的匝间接触,这对于无绝缘高温超导线圈中的电流共享以及随之而来... 详细信息

在高场磁体中,压缩磁径向应力比拉伸应力更受青睐,原因是它能降低磁体绕组内的整体峰值磁应力.这对于无绝缘高温超导(Ni HTs)磁体尤为重要,因为压缩径向应力能够产生良好的匝间接触,这对于无绝缘高温超导线圈中的电流共享以及随之而来的自保护行为至关重要.根据关键磁体设计参数(如目标中心场、背景磁场、内外绕组直径和外部径向堆叠),我们给出了可以从解析上确定高场超导磁体具有压缩径向应力的电磁-力学条件.本文提出的方法可以识别干绕线圈中径向匝间接触行为的3种不同模式:(1)完全分离;(2)完全接触;以及(3)混合模式(即部分分离和接触).文章随后提出一种使用完全压缩径向应力电磁-力学条件来计算干绕线圈中应力分布的解析方法.并通过有限元分析示例验证了解析方法与数值方法的良好一致性.文章结果可以帮助磁体工程师在早期设计阶段更好地概览高场超导磁体的电磁-力学行为.

关键词：高温超导背景磁场径向应力力学条件拉伸应力匝间接触行为混合模式

Adiponectin restores the obesity-induced impaired immunomodulatory function of mesenchymal stromal cells via glycolytic reprogramming

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Acta Pharmaceutica sinica B 2024年第1期14卷 273-291页

作者： Duc-Vinh Pham Thi-Kem Nguyen Bao-Loc Nguyen Jong-Oh Kim Jee-Heon Jeong inho choi Pil-Hoon Park Department of Pharmacology Hanoi University of PharmacyHanoi 100000Viet Nam College of Pharmacy Yeungnam UniversityGyeongsan 38541Republic of Korea Department of Medical Biotechnology Yeungnam UniversityGyeongsan 38541Republic of Korea Research institute of Cell Culture Yeungnam UniversityGyeongsan 38541Republic of Korea Department of Precision Medicine School of MedicineSungkyunkwan UniversitySuwon 16419Republic of Korea

Obesity has been known to negatively modulate the life-span and immunosuppressive potential of mesenchymal stromal cells(MsC).However,it remains unclear what drives the compromised potency of obese *** this study,we examined the involvement of adiponectin,an adipose tissuederived hormone,in obesity-induced impaired therapeutic function of ***-induced obesity leads to a decrease in serum adiponectin,accompanied by impairment of survival and immunomodulatory effects of adipose-derived MsC(ADsC).interestingly,priming with globular adiponectin(gAcrp)improved the immunomodulatory potential of obese *** effects were also observed in lean *** addition,gAcrp potentiated the therapeutic effectiveness of ADsC in a mouse model of Dss-induced ***,while obesity inhibited the glycolytic capacity of MsC,gAcrp treatment induced a metabolic shift toward glycolysis through activation of adiponectin receptor type 1/p38 MAPK/hypoxia inducible factor-1a *** findings suggest that activation of adiponectin signaling is a promising strategy for enhancing the therapeutic efficacy of MsC against immune-mediated disorders.

关键词： Adiponectin Adipose-derived stromal cells Colitis Glycolytic induction HiF1a immunomodulation Mesenchymal stromal cells Obesity

Change in Grain-size Composition of Lignite under Cyclic Freezing-Thawing and Wetting-Drying

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Natural Resources 2024年第1期15卷 17-27页

作者： Natalia s. Batugina Vladislav i. Fedorov Chersky institute of Mining of the North siberian Branch Russian Academy of sciences Yakutsk Russia

The paper presents the change in grain-size composition of lignite under cyclic freezing-thawing (FTC) and wetting-drying (WDC). The article shows that in the spring and autumn periods the lignites can be subjected to repeated freezing-thawing and wetting-drying, which determines the possibility of changing their grain-size composition and structure. Experimental studies in laboratory conditions on the influence of cyclic freezing-thawing (FTC) and wetting-drying (WDC) on the quality indicators of lignites have been carried out, their granulometric (fractional) composition has been studied. Freezing-thawing cycle conditions are as follows (FTC): minimum exposure temperature: -20°C;maximum: +5°C;relative humidity: 30%;number of processing cycles: 3. Wetting-drying cycles are as follows (WDC): drying temperatures are +20, +40, +60, +80°C, drying time 90 minutes, the coals are further subjected to rain (soaking) for a period of water saturation to humidity of 30% - 40% and dry again. The number of wetting-drying cycles is 3 times. The tests have revealed the destructive effects of FTC and WDC on the samples of lower metamorphic grade coal, and the cycles of wet-dry lead to the much higher yield of fine sizes (-6+0;-13+0 mm) than the cycles of freeze-thaw. Furthermore, it is found that the increase in the yield of fines depends on the heating temperature: coal disintegration proceeds more intensively at a higher temperature of drying.

关键词： Lignite Freezing-Thawing Cycle Wetting-Drying Cycle Grain size Composition Dust Coal storage Loss Quality

A Dimensional Reduction Approach Based on Essential Constraints in Linear Programming

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American Journal of Operations Research 2024年第1期14卷 1-31页

作者： Eirini i. Nikolopoulou George s. Androulakis Department of Mathematics University of Patras Patras Greece Department of Business Administration University of Patras Patras Greece

This paper presents a new dimension reduction strategy for medium and large-scale linear programming problems. The proposed method uses a subset of the original constraints and combines two algorithms: the weighted average and the cosine simplex algorithm. The first approach identifies binding constraints by using the weighted average of each constraint, whereas the second algorithm is based on the cosine similarity between the vector of the objective function and the constraints. These two approaches are complementary, and when used together, they locate the essential subset of initial constraints required for solving medium and large-scale linear programming problems. After reducing the dimension of the linear programming problem using the subset of the essential constraints, the solution method can be chosen from any suitable method for linear programming. The proposed approach was applied to a set of well-known benchmarks as well as more than 2000 random medium and large-scale linear programming problems. The results are promising, indicating that the new approach contributes to the reduction of both the size of the problems and the total number of iterations required. A tree-based classification model also confirmed the need for combining the two approaches. A detailed numerical example, the general numerical results, and the statistical analysis for the decision tree procedure are presented.

关键词： Linear Programming Binding Constraints Dimension Reduction Cosine similarity Decision Analysis Decision Trees

sANC Monte Carlo programs for small-angle Bhabha scattering

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Chinese Physics C 2024年第4期48卷 14-19页

作者： A.B.Arbuzov s.G.Bondarenko i.R.Boyko L.V.Kalinovskaya A.A.Kampf R.R.sadykov V.L.Yermolchyk Bogoliubov Laboratory of Theoretical Physics JINRDubna141980 Russia Dzhelepov Laboratory of Nuclear Problems JINRDubna141980 Russia Dubna state University Dubna141982 Russia

Luminosity monitoring at e^(+)e^(−)colliders was investigated using sANC Monte Carlo event generator RenesANCe and integrator MCsANC for simulation of Bhabha scattering at low *** are presented for center-of-mass energies of the Z boson resonance and at 240 GeV for the conditions of typical luminosity *** is shown that bremsstrahlung events with extremely low electron scattering angles are relevant to match the precision tags of future electron-positron colliders.

关键词： luminosity Bhabha scattering QED Monte Carlo simulation

Are population cycles recovering?

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integrative Zoology 2024年第3期19卷 538-547页

作者： Vasily D.YAKUsHOV Boris i.sHEFTEL A.N.severtsov institute of Ecology and Evolution of the Russian Academy of sciences MoscowRussia

The dynamics of populations of small mammals of Central siberia was *** studies were carried out at the Yenisei ecological station“Mirnoye”of the *** institute of Ecology and Evolution,Russian Academy of *** time series analysis was performed by the wavelet transform using the statistical data processing language *** the 20th century,the dynamics of the population of the community and some of its constituent species(sorex araneus;***;***;***;***;Craseomys rufocanus;Clethrionomys rutilus;Microtus oeconomus;***)were characterized by a 4-year *** type of dynamics changed to noncyclic by the nineties,but by 2022,four species(***,***,***,and ***)and the community as a whole showed a tendency toward recovery of population *** remaining species were characterized by consistently low numbers with irregular low amplitude fluctuations.

关键词： population cycles small mammals time-series analysis wavelet transform

superexchange and charge transfer in the nickelate superconductor La3Ni2O7 under pressure

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science China(Physics,Mechanics & Astronomy) 2024年第11期Mechanics & Astronomy) .卷 5-12页

作者： Wéi Wú Zhihui Luo Dao-Xin Yao Meng Wang Center for Neutron science and Technology Guangdong Provincial Key Laboratory of Magnetoelectric Physics and DevicesSchool of Physics Sun Yat-sen University

Recently, a bulk nickelate superconductor La3Ni2O7is discovered at pressures with a remarkable high transition temperature Tc～ 80 K. Here, we study a Hubbard model with tight-binding parameters derived from ab initio calculations of La3Ni2O7,by employing large scale determinant quantum Monte Carlo and cellular dynamical mean-field theory. Our result suggests that the superexchange couplings in this system are comparable to that of cuprates. The system is a charge transfer insulator as the hole concentration becomes four per site at large Hubbard U. Upon hole doping, two low-energy spin-singlet bands emerge in the system exhibiting distinct correlation properties: while the one composed of the out-of-plane Ni-d3z2-r2and O-pzorbitals demonstrates strong antiferromagnetic correlations and narrow effective bandwidth, the in-plane singlet band consisting of the Ni-dx2-y2and O-px/pyorbitals is in general more itinerant. Over a broad range of hole doping, the doped holes occupy primarily the dx2-y2and px/pyorbitals, whereas the d3z2-r2and pzorbitals retain underdoped. We propose an effective t-J model to capture the relevant physics and discuss the implications of our result for comprehending the La3Ni2O7superconductivity.

关键词： superconductivity nickelate superconductors Hubbard model superexchange charge transfer insulator quantum Monte Carlo