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Superexchange and charge transfer in the nickelate superconductor La_(3)Ni_(2)O_(7) under pressure

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Science China(Physics,Mechanics & Astronomy) 2024年第11期67卷 1-8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 PhysicsSun Yat-sen UniversityGuangzhou 510275China

Recently, a bulk nickelate superconductor La_(3)Ni_(2)O_(7) is discovered at pressures with a remarkable high transition temperature T_(c)~ 80 K. Here, we study a Hubbard model with tight-binding parameters derived from ab initio calculations of La_(3)Ni_(2)O_(7),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-d_(3z^(2)-r^(2)) and O-p_(z) orbitals demonstrates strong antiferromagnetic correlations and narrow effective bandwidth, the in-plane singlet band consisting of the Ni-d_(x^(2)-y^(2)) and O-p_(x)/p_(y) orbitals is in general more itinerant. Over a broad range of hole doping, the doped holes occupy primarily the d_(x^(2)-y^(2)) and p_(x)/p_(y) orbitals, whereas the d_(3z^(2)-r^(2)) and p_(z) orbitals retain underdoped. We propose an effective t-J model to capture the relevant physics and discuss the implications of our result for comprehending the La_(3)Ni_(2)O_(7) superconductivity.

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

Quantum algorithms for matrix operations and linear systems of equations

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Communications in Theoretical Physics 2024年第3期76卷 100-112页

作者： Wentao Qi Alexandr i Zenchuk Asutosh Kumar Junde Wu School of Mathematical Sciences Zhejiang UniversityHangzhou 310027China Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry RAS ChernogolovkaRussia P.G.Department of Physics Gaya CollegeMagadh UniversityRampurGaya 823001India Harish-Chandra Research institute HBNIChhatnag RoadJhunsiPrayagraj 211019India Vaidic and Modern Physics Research Centre Bhagal BhimBhinmalJalore 343029India

Fundamental matrix operations and solving linear systems of equations are ubiquitous in scientific *** the‘sender-receiver’model,we propose quantum algorithms for matrix operations such as matrix-vector product,matrix-matrix product,the sum of two matrices,and the calculation of determinant and inverse *** encode the matrix entries into the probability amplitudes of the pure initial states of *** applying proper unitary transformation to the complete quantum system,the desired result can be found in certain blocks of the receiver’s density *** quantum protocols can be used as subroutines in other quantum ***,we present an alternative quantum algorithm for solving linear systems of equations.

关键词： matrix operation systems of linear equations ‘sender-receiver’quantum computation model quantum algorithm

Near resonance vibration isolation on a levered-dual response(LEDAR)Coulomb-damped system by differential preloads/offsets in linear springs

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 1033-1050页

作者： T.i.TOLUWALOJU C.K.THEiN D.HALiM Department of Mechanical Materials and Manufacturing EngineeringUniversity of Nottingham Ningbo ChinaNingbo 315100Zhejiang ProvinceChina Nottingham Ningbo China Beacons of Excellence Research and innovation institute University of Nottingham Ningbo ChinaNingbo 315048Zhejiang ProvinceChina

The levered-dual response(LEDAR)Coulomb-damped system attains near resonant vibration isolation by differential preloads/offsets in linear *** takes the advantages of both the preloads/offsets in linear springs and the guiderail friction for realizing different levels of vibration *** isolation capacities are investigated on the strategies with both the horizontal and vertical guiderails,with the horizontal rail only,and without *** compressive preloads generally result in the consumption of most of the initial excitation energy so as to overcome the potential *** isolation onsets at the frequency ratio of 1∓0.095 on the left-hand side(LHS)and the right-hand side(RHS)of the lever are relative to the load plate *** observed near resonant isolation thus makes the LEDAR system a candidate for the isolation of the mechanical systems about resonance while opening a path for simultaneous harvesterisolation functions and passive functions at extreme frequencies.

关键词： lever ratio Coulomb damping preload tension/compression isolation band/depth offset potential

Deep bed filtration model for cake filtration and erosion

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 355-372页

作者： L.i.KUZMiNA Y.V.OSiPOV A.R.PESTEREV Department of Applied Mathematics HSE UniversityMoscow 101000Russia Department of Computer Science and Applied Mathematics Moscow State University of Civil EngineeringMoscow 129337Russia

Many phenomena in nature and technology are associated with the filtration of suspensions and colloids in porous media. Two main types of particle deposition,namely, cake filtration at the inlet and deep bed filtration throughout the entire porous medium, are studied by different models. A unified approach for the transport and deposition of particles based on the deep bed filtration model is proposed. A variable suspension flow rate, proportional to the number of free pores at the inlet of the porous medium, is considered. To model cake filtration, this flow rate is introduced into the mass balance equation of deep bed filtration. For the cake filtration without deposit erosion,the suspension flow rate decreases to zero, and the suspension does not penetrate deep into the porous medium. in the case of the cake filtration with erosion, the suspension flow rate is nonzero, and the deposit is distributed throughout the entire porous medium. An exact solution is obtained for a constant filtration function. The method of characteristics is used to construct the asymptotics of the concentration front of suspended and retained particles for a filtration function in a general form. Explicit formulae are obtained for a linear filtration function. The properties of these solutions are studied in detail.

关键词： deep bed filtration cake filtration porous medium particle deposition and erosion analytical solution concentration front

Phase composition,conductivity,and sensor properties of cerium-doped indium oxide

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Nano Materials Science 2024年第2期6卷 193-200页

作者： M.i.ikim G.N.Gerasimov V.F.Gromov O.J.ilegbusi L.i.Trakhtenberg N.N.Semenov Federal Research Center for Chemical Physics of RAS MoscowRussia University of Central Florida OrlandoFLUSA Moscow institute of Physics and Technology(State University) DolgoprudnyMoscow RegionRussia Lomonosov Moscow State University MoscowRussia

The hydrothermal synthesis of in_(2)O_(3)and CeO_(2)–in_(2)O_(3)is investigated as well as the properties of sensor layers based on these *** the synthesis of in_(2)O_(3),intermediate products in(OH)_(3)and inOOH are formed,which are the precursors of stable cubic(c-in_(2)O_(3))and metastable rhombohedral(rh-in_(2)O_(3))phases,respectively.A transition from c-in_(2)O_(3)to rh-in_(2)O_(3)is observed with the addition of CeO_(2).The introduction of cerium into rh-in_(2)O_(3)results in a decrease in the sensor response to hydrogen,while it increases in composites based on c-in_(2)O_(3).The data on the sensor activity of the composites correlate with XPS results in which CeO_(2)causes a decrease in the concentrations of chemisorbed oxygen and oxygen vacancies in rh-in_(2)O_(3).The reverse situation is observed in composites based on c-in_(2)O_(3).Compared to in_(2)O_(3)and CeO_(2)–in_(2)O_(3)obtained by other methods,the synthesized composites demonstrate maximum response to H_(2)at low temperatures by 70–100℃,and have short response time(0.2–0.5 s),short recovery time(6–7 s),and long-term stability.A model is proposed for the dependence of sensitivity on the direction of electron transfer between in_(2)O_(3)and CeO_(2).

关键词： Cerium oxide indium oxide Nanocomposite Hydrothermal method Cubic phase Rhombohedral phase Sensor response Conductivity Hydrogen Response/recovery time

Post processing of additive manufactured Mg alloys:Current status,challenges,and opportunities

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Journal of Magnesium and Alloys 2024年第4期12卷 1283-1310页

作者： Nooruddin Ansari Fatima Ghassan Alabtah Mohammad i.Albakri Marwan Khraisheh Mechanical Engineering Program Texas A&M University at QatarP.O.Box 23874DohaQatar

Magnesium(Mg)and its alloys are emerging as a structural material for the aerospace,automobile,and electronics industries,driven by the imperative of weight *** are also drawing notable attention in the medical industries owing to their biodegradability and a lower elastic modulus comparable to *** ability to manufacture near-net shape products featuring intricate geometries has sparked huge interest in additive manufacturing(AM)of Mg alloys,reflecting a transformation in the manufacturing ***,AM of Mg alloys presents more formidable challenges due to inherent properties,particularly susceptibility to oxidation,gas trapping,high thermal expansion coefficient,and low solidification *** leads to defects such as porosity,lack of fusion,cracking,delamination,residual stresses,and inhomogeneity,ultimately influencing the mechanical,corrosion,and surface properties of AM Mg *** address these issues,post-processing of AM Mg alloys are often needed to make them suitable for *** present article reviews all post-processing techniques adapted for AM Mg alloys to date,including heat treatment,hot isostatic pressing,friction stir processing,and surface *** utilization of these methods within the hybrid AM process,employing interlayer post-processing,is also *** post-processing conditions are reported,and their influence on the microstructure,mechanical,and corrosion properties are ***,future prospects and research directions are proposed.

关键词： Magnesium alloy Additive manufacturing Post-processing Heat treatment HiP

Effectiveness of external prestressing in enhancing the non-ductile hanger failure mechanism in reinforced concrete inverted T-beams

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Frontiers of Structural and Civil Engineering 2024年第7期18卷 1050-1065页

作者： Ahmed M.ATTA Reda N.BEHiRY Mohammed i.HARAZ Structural Engineering Department Faculty of EngineeringTanta UniversityTanta 33511Egypt Nile Higher institute for Engineering and Technology Mansoura 11001Egypt

Recently,inverted T-beams have been used in reinforced concrete(RC)bridges to support transverse precast *** T-beams,contrary to practice with conventional beams,are loaded on the flanges upper *** loading configuration causes hanger failure due to the generation of vertical tensile stresses near the bottom of the *** key purpose of this study is to investigate the efficiency of vertical external prestressing stainless-steel bars in mitigating non-ductile hanger failure in reinforced concrete inverted *** experimental study on six inverted-T beams,including two un-strengthened specimens,was carried *** study showed that the value of the prestressing level had a considerable impact on the performance of hanger mechanism in relation to crack pattern,ultimate loads,cracking behavior,load-deflection,strains,and *** experimental results indicated that the suggested method for strengthening inverted T-beams had efficacy in reducing the seriousness of the non-ductile hanger failure and resulted in a strength increase of up to 53% when compared to that of the un-strengthened ***,two analytical models for estimating the hanger capacity and the average crack width of the strengthened RC inverted T-beams were *** models that were proposed exhibited a high degree of agreement with the experimental results.

关键词： RC bridges inverted T-beams strengthening hanger failure external prestressing

immunotherapy in gastric cancer with liver metastasis:Challenges and opportunities

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World Journal of Gastrointestinal Surgery 2024年第6期16卷 1513-1516页

作者： Murat Bardakçi Yakup Ergun Department of Medical Oncology Diyarbakır Gazi Yasargil Training and Research HospitalDiyarbakir 021000KayapinarTürkiye Department of Medical Oncology Antalya City HospitalAntalya 07080Türkiye

in this editorial,we review the article by Liu et al published in the World Journal of Gastrointestinal Surgery investigating the efficacy and safety of immunotherapy in patients with gastric cancer(GC)and liver ***,the fifth most com-monly diagnosed malignancy worldwide,presents a significant challenge due to its multifactorial etiology and a grim prognosis for unresectable or recurrent *** advent of immune checkpoint inhibitors(iCis)has revolutionized oncology;yet liver metastasis has been associated with reduced response rates,progression-free survival,and overall survival in various *** Che-ckMate-649 and KEYNOTE-859 trials demonstrated promising results with iCis in advanced GC,particularly in patients with liver ***,a meta-analysis of liver metastatic solid tumors revealed worse outcomes with iCis,high-lighting the need for further *** combined therapies,including iCis with local treatments,show promise in improving outcomes,the nuanced landscape of iCis in liver metastatic GC necessitates continued research for robust *** current contradictions in the literature underscore the impor-tance of cautious interpretation and the exploration of tailored approaches to enhance clinical efficacy in this challenging patient population.

关键词： Gastric cancer Liver metastasis immunotherapy immune checkpoint in-hibitors Transarterial chemoembolization Tumor microenvironment

VR-based digital twin for remote monitoring of mining equipment:Architecture and a case study

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虚拟现实与智能硬件（中英文） 2024年第2期6卷 100-112页

作者： Jovana PLAVŠiĆ ilija MiŠKOViĆNorman BKeevil Norman B.Keevil institute of Mining Engineering University of British ColumbiaVancouverBC V6T 1Z4Canada

Background Traditional methods for monitoring mining equipment rely primarily on visual inspections,which are time-consuming,inefficient,and *** article introduces a novel approach to monitoring mission-critical systems and services in the mining industry by integrating virtual reality(VR)and digital twin(DT)***-based DTs enable remote equipment monitoring,advanced analysis of machine health,enhanced visualization,and improved decision *** This article presents an architecture for VR-based DT development,including the developmental stages,activities,and stakeholders involved.A case study on the condition monitoring of a conveyor belt using real-time synthetic vibration sensor data was conducted using the proposed *** study demonstrated the application of the methodology in remote monitoring and identified the need for further development for implementation in active mining *** article also discusses interdisciplinarity,choice of tools,computational resources,time and cost,human involvement,user acceptance,frequency of inspection,multiuser environment,potential risks,and applications beyond the mining *** The findings of this study provide a foundation for future research in the domain of VR-based DTs for remote equipment monitoring and a novel application area for VR in mining.

关键词： Virtual reality Digital twin Condition monitoring Mining equipment