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Quantized bound states around a vortex in anisotropic superconductors

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Science China(Physics,Mechanics & Astronomy) 2024年第6期67卷 146-155页

作者： ke xiang Da Wang Qiang-Hua Wang National Laboratory of Solid State Microstructures&School of Physics Nanjing UniversityNanjing 210093China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093China

The bound states around a vortex in anisotropic superconductors is a longstanding yet important *** this work,we develop a variational theory on the basis of the Andreev approximation to obtain the energy levels and wave functions of the low-energy quantized bound states in superconductors with anisotropic pairing on arbitrary Fermi *** the case of circular Fermi surface,the effective Schr¨odinger equation yielding the bound state energies gets back to the theory proposed by Volovik and Kopnin many years *** generalization here enables us to prove the equidistant energy spectrum inside a vortex in a broader class of *** importantly,we are now able to obtain the wave functions of these bound states by projecting the quasiclassical wave function on the eigenmodes of the effective Schr¨odinger equation,going beyond the quasiclassical Eilenberger results,which,as we find,are sensitive to the scattering *** the case of isotropic Fermi surface,the spatial profile of the low-energy local density of states is dominated near the vortex center and elongates along the gap antinode directions,in addition to the ubiquitous Friedel oscillation arising from the quantum inteference neglected in the Eilenberger ***,as a consequence of the pairing anisotropy,the quantized wave functions develop a peculiar distribution of winding number,which reduces stepwise towards the vortex *** work provides a flexible way to study the vortex bound states in the future.

关键词： vortex bound state anisotropic superconductor Andreev approximation

An integrative mathematical model of microwave ion thruster for mHz-frequency thrust noise analysis

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Chinese Journal of Aeronautics 2024年第4期37卷 121-136页

作者： xiang NIU Hui LIU Daren yu Plasma Propulsion Laboratory Harbin Institute of TechnologyHarbin 150001China

Many high-precision space missions need thrusters to produce thrust with low noise to compensate for disturbances and ensure satellite platform stability. Microwave ion thruster is characterized with a wide thrust range and potential for these missions. A cost-effective and accurate mathematical model is crucial for mHz-frequency thrust noise analysis and feedback controller design. The Particle-In-Cell(PIC) and global models are two common simulation tools. The PIC model is characterized with high accuracy but huge computation cost, which is difficult to analyze long-time performance characteristics. Now, the global model is only used for the discharge chamber with low accuracy and cannot reflect ion extraction properties. In this paper, an integrative mathematical model is built for a 1-cm microwave ion thruster and can reflect ion beamlet divergence and impingement on the Accelerator Grid(AG). Simulation results show good agreement with experiments at 0.06 sccm. However, the model demonstrates worse consistency with experiments when the flux increases to 0.1 sccm, which may be because the influence of neutral gas on the Electron Cyclotron Resonance(ECR) is not considered in the model. A long-time(1000 s) simulation is conducted with this model under 35 μN. It takes 3 hrs, and the thrust noise reaches 1 μN/Hz^(0.5) at 1 mHz.

关键词： Electric propulsion Microwave ion thruster Integrative model Sheath property Ion beamlet divergence Thrust noise Plasma

Single-atom Co alloyed Ru for electrocatalytic nitrite reduction to ammonia

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Nano Research 2024年第5期17卷 3660-3666页

作者： Fuzhou Wang Jiaqi xiang Guike Zhang Kai Chen ke Chu School of Materials Science and Engineering Lanzhou Jiaotong UniversityLanzhou 730070China

Electrochemical converting NO_(2)^(-)into NH_(3)(NO_(2)RR)holds an enormous prospect to attain efficient NH_(3) electrosynthesis and polluted NO_(2)^(-)***,we report single-atom Co alloyed Ru(Co_(1)Ru)as an efficient and durable NO_(2)RR *** experimental and theoretical investigations reveal that single-atom Co alloying of Ru enables the construction of Co_(1)-Ru heteronuclear active sites to synergistically promote NO_(2)^(-)activation/hydrogenation while suppressing the competitive H_(2) evolution,rendering the greatly enhanced activity and selectivity of Co_(1)Ru towards the NO_(2)***,Co_(1)Ru assembled within a flow cell exhibits an impressive NH_(3) yield rate of 2379.2μmol·h^(-1)·cm^(-2) with an NH_(3)-Faradaic efficiency of 92%at a high current density of 415.9 mA·cm^(-2),which is among the highest NO_(2)RR performances reported to date.

关键词： electrochemical converting NO_(2)-into NH3 single-atom alloys theoretical computations industrial-level current density

Bayesian partial pooling to reduce uncertainty in overcoring rock stress estimation

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1192-1201页

作者： yu Feng ke Gao Suzanne Lacasse Norwegian Geotechnical Institute OsloNorway Department of Earth and Space Sciences Southern University of Science and TechnologyShenzhenChina

The state of in situ stress is a crucial parameter in subsurface engineering,especially for critical projects like nuclear waste *** one of the two ISRM suggested methods,the overcoring(OC)method is widely used to estimate the full stress tensors in rocks by independent regression analysis of the data from each OC ***,such customary independent analysis of individual OC tests,known as no pooling,is liable to yield unreliable test-specific stress estimates due to various uncertainty sources involved in the OC *** address this problem,a practical and no-cost solution is considered by incorporating into OC data analysis additional information implied within adjacent OC tests,which are usually available in OC measurement ***,this paper presents a Bayesian partial pooling(hierarchical)model for combined analysis of adjacent OC *** performed five case studies using OC test data made at a nuclear waste repository research site of *** results demonstrate that partial pooling of adjacent OC tests indeed allows borrowing of information across adjacent tests,and yields improved stress tensor estimates with reduced uncertainties simultaneously for all individual tests than they are independently analysed as no pooling,particularly for those unreliable no pooling stress estimates.A further model comparison shows that the partial pooling model also gives better predictive performance,and thus confirms that the information borrowed across adjacent OC tests is relevant and effective.

关键词： Overcoring stress measurement Uncertainty reduction Partial pooling Bayesian hierarchical model Nuclear waste repository

Microstructure and mechanical properties of a cast TRIP-assisted multiphase stainless steel

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China Foundry 2024年第3期21卷 221-228页

作者： Meng-xin Wang Zi-xiang Wu Jing-yu He xiang Chen School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China key Laboratory for Advanced Materials Processing Technology Ministry of EducationBeijing 100084China

Stainless steels are used in a wide range of complex environments due to their excellent corrosion *** stainless steels can offer an excellent combination of strength,toughness and corrosion resistance due to the coexistence of different *** microstructure and mechanical properties of a novel cast multiphase stainless steel,composed of martensite,ferrite,and austenite,were investigated following appropriate heat treatment processes:solution treatment at 1,050℃ for 0.5 h followed by water quenching to room temperature,and aging treatment at 500℃ for 4 h followed by water quenching to room *** show reversed austenite is formed by diffusion of Ni element during aging process,and the enrichment of Ni atoms directly determines the mechanical stability of *** austenite with a lower Ni content undergoes a martensitic transformation during plastic *** tensile strength of the specimen exceeds 1,100 MPa and the elongation exceeds 24%after solid solution,and further increases to 1,247 MPa and 25%after aging *** enhancement is due to the TRIP effect of austenite and the precipitation of the nanoscale G-phase pinning dislocations in ferrite and martensite.

关键词： multiphase stainless steel mechanical properties TRIP effect reversed austenite G-phase

Unraveling magnetic properties and martensitic transformation in Mn-rich Ni-Mn-Sn alloys:first-principles calculations and experiments

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Rare Metals 2024年第4期43卷 1769-1785页

作者： yu Zhang Jing Bai ke-Liang Guo Jia-Xin Xu Jiang-Long Gu Nicola Morley Qui-Zhi Gao yu-Dong Zhang Claude Esling xiang Zhao Liang Zuo key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Material Science and EngineeringNortheastern UniversityShenyang110819China key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province School of Resources and MaterialsNortheastern University at QinhuangdaoQinhuangdao066004China Department of Material Science and Engineering University of SheffieldSheffieldS13JDUK State key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao066004China Laboratoire d’Étude des Microstructures Et de Mécanique des Matériaux University of Lorraine57045MetzFrance

We have investigated the phase stability,magnetic properties,and martensitic transformation thermodynamics/kinetics of the Ni_(24-x)Mn_(18+x+y)Sn_(6-y)(x,y=0,1,2)system by combining the first-principles calculations and *** calculation results show that the optimized lattice parameters are consistent with the experimental ***,we obtain the relation equation for the austenite formation energy(E_(form-A))and Mn content(X_(Mn)):E_(form-A)=507.358X_(Mn)-274.126,as well as for the six-layer modulated(6M)martensite formation energy(E_(form-6M))and Ni content(X_(Ni)):E_(form-6M)=-728.484X_(Ni)+*** ternary phase diagram of the total magnetic moment was *** excess Mn will reduce the total magnetic moment of 6M(Mag6M)and non-modulated(NM)(MagNM)martensites,with the following equations relating the total magnetic moment and Mn content:Mag_(6M)=-15.905X_(Mn)+7.902and Mag_(NM)=-14.781X_(Mn)+7.411,while the effect on austenite is *** variation of total magnetic moment is mainly dominated by the Mn atomic magnetic *** 3d electrons of Mn_(Sn)(Mn at Sn sublattice)play an important role in magnetic properties from the perspective of the electronic density of *** on the thermodynamics of martensitic transformation,the alloys will likely undergo austenite?6M?NM transformation *** the thermodynamic and kinetic results,the martensitic transformation temperature decreases with x increasing and increases with y *** results are expected to provide reference for predicting the phase stability and magnetic properties of NiMn-Sn alloys.

关键词： Ni-Mn-Sn First-principles calculations Martensitic transformation Magnetic property Kinetics

103 GHz germanium-on-silicon photodiode enabled by an optimized U-shaped electrode

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Photonics Research 2024年第1期12卷 1-6页

作者： Yang Shi xiang Li Mingjie Zou yu yu Xinliang Zhang Wuhan National Laboratory for Optoelectronics&School of Optical and Electronic Information Huazhong University of Science and TechnologyWuhan 430074China School of Mechanical Engineering and Electronic Information China University of GeosciencesWuhan 430074China Optics Valley Laboratory Wuhan 430074China Xidian University Xi’an 710126China

High-performance germanium photodiodes are crucial components in silicon photonic integrated circuits for large-capacity data ***,the bandwidths of most germanium photodiodes are limited by the intractable resistance–capacitance parasitic ***,we introduce a unique U-shaped electrode to alleviate this issue,reducing the parasitic effect by 36%without compromising any other ***,a large bandwidth of 103 GHz,an optical responsivity of 0.95 A/W at 1550 nm,and a dark current as low as 1.3 nA are achieved,leading to a record high specific *** is the first breakthrough to 100 GHz bandwidth among all vertical germanium photodiodes,to the best of our *** eye diagrams of 120 Gb/s on-off keying and 200 Gb/s four-level pulse amplitude signals are well *** work provides a promising solution for chip-based ultra-fast photodetection.

关键词： Gb/s shaped electrode

Photoinduced superlubricity on TiO_(2) surfaces

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Friction 2024年第3期12卷 428-438页

作者： ke HAN Liran MA yu TIAN Jianbin LUO State key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China Received:16 September 2022/Revised:28 October 2022/Accepted:27 December 2022The author(s)2022.

Superlubricity control is of great interest in both industry and scientific research,and several methods have been proposed to achieve this *** this work,ultraviolet(UV)light was introduced into titanium dioxide(TiO_(2))and silicon nitride(Si_(3)N_(4))tribosystems to accomplish photoinduced *** friction coefficients(COFs)between Si_(3)N_(4) balls and TiO_(2) plates in the mixtures of sulfuric acid(H^(2)SO_(4))solution and glycerol solution were obviously reduced,and the system entered the superlubricity region(COFkey to the photoinduced superlubricity in this *** findings showed one method for achieving superlubricity by introducing a light field that could be further applied to special working conditions.

关键词： light control friction superlubricity glycerol titanium dioxide(TiO_(2))

Mechanical allodynia and affective behavior are improved by INI-0602,a gap junction hemichannel inhibitor,in a rat model of neuropathic pain induced by sciatic nerve injury

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中国药理学与毒理学杂志 2016年第10期30卷 1027-1028页

作者： ZHANG Xiao-min FAN Li-xia PENG yue-xia SONG Qi xiang yu-ke WU Wei-li WANG Qin TAO Liang Department of Pharmacology Zhongshan School of MedicineSun Yat-Sen University

OBJECTIVE To investigated the effects of INI-0602 on nociceptive reflex,depression-associated andanxiety-related behaviors caused by neuropathic pain in sciatic nerve injury *** Male rat were subjected to sciatic nerve injury(SNI)or sham *** received daily treatment with INI-0602 intrathecally,at a dose of 0.25μg/10μ*** response frequency to mechanical allodynia in animals was measured with von Frey hairs on day 1,3,5,7,14,*** were evaluated in the forced swimming test(FST)test,tail suspension test(TST),sucrose preference test(SPT)for depression-like *** performed open field test(OFT)and elevated plus-maze test(EPM)to evaluate anxiety-associated ***,we investigated the alterations of NMDA receptor and the brain-derived neurotrophic factor(BDNF)and also the expression of connexin43 and connexin32,structure protein of gap junction channel,on the protein level and the number of activated astrocyte showed by *** The SNI procedure produced mechanical allodynia and accompanied with depressive-like and anxiety-like *** with INI-0602 produced a significant analgesic effect in SNI rats at day 7(model+NS:11.017±1.506 g;model+INI-0602:31.157±1.532 g,P<0.01),and still obviously on the 21th day(31.067±1.787,P<0.01).INI-0602 could also improve the performance of sciatic nerve injury rats among program behavior tests related to depression and *** parallel with relief of pain,the alterations of NMDA receptor and the brain-derived neurotrophic factor(BDNF),involved in central sensitization and synaptic plasticity,were ***-0602 not only could inhibited spared nerve injury induced up-regulated of NR2B and phosphorylation NR2B in early and late neuropathic pain(early phase:Nr2b:2.897±0.228,P<0.01;p-Nr2b:2.984±0.236,P<0.01;late phase:Nr2b:2.594±0.187,P<0.01;p-Nr2b:3.124±0.330,P<0.01),but also could inhibit the increased of BDNF in the early(model+NS:3.637±0.381,model+INI-0602:1.148±0.

关键词： INI-0602 gap junction hemichannel inhibitor neuropathic pain depression anxiety