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Investigations of nuclear chirality at iThemba LABS

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Frontiers of physics 2024年第2期19卷 7-38页

作者： R.A.Bark e.A.Lawrie c.Liu S.y.Wang iThemba Laboratory for Accelerator Based Sciences National Research FoundationP.O.Box 722Somerset-West 7129South Africa Department of physics University of the Western CapePrivate Bag X177535BellvilleSouth Africa Shandong provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial environment Institute of Space SciencesShandong UniversityWeihai 264209China

progress in the studies of chirality in atomic nuclei at iThemba LABS is *** regions of chirality,around mass 80 and 190 have been discovered using the AFRODITe array,specifically in the nuclei^(74)As,^(78,80,82)Br,^(81)Kr,and^(193,194,198)*** phenomena have been observed,including multiple chiral bands in the same nucleus,the coexistence of octupole correlations and nuclear chirality,and the coexistence of pseudo spin and nuclear *** best example of chiral degeneracy to date was found in ^(194)*** level scheme of ^(106)Ag has been revisited and interpreted in terms of two-and four-quasiparticle *** using the particle-rotor model have shown that the fingerprints of chirality in the two-quasiparticle system only can occur in an idealised model *** systems with a higher number of quasiparticles,the calculations showed that nuclear chirality can persist.

关键词： chirality high-spin states particle-rotor model

cognition on oxidation behavior of Ni-based superalloy GH4742 when exposed to water vapor

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Journal of Materials Science & Technology 2024年第7期174卷 15-22页

作者： H.Xu S.F.yang e.H.Wang c.y.Guo y.S.Liu X.M.Hou y.L.Zhang State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Institute for carbon Neutrality University of Science and Technology BeijingBeijing 100083China

The oxidation behavior of Ni-based superalloy GH4742 exposed to water vapor was investigated at 900-1100℃for 50 h in Ar+20%H_(2)O,with Ar+20%O_(2)included for *** presence of H_(2)O is adverse to formation of continuous cr_(2)O_(3)oxide layer but contributes to generation of big *** on this,Ni^(2+)and co^(2+)are more easily to diffuse towards the outermost oxide layer(OOL),forming non-protective Ni-and co-rich oxides with high *** leads to a higher weight gain in Ar+20%H_(2)O than that in Ar+20%O_(2).At elevated temperatures,the spallation of oxide scale occurs while the consumption of cr is reduced in Ar+20%H_(2)O,and the contents of Ni-and co-rich oxides at this moment are reduced in the *** oxidation mechanism was also discussed.

关键词： GH4742 Superalloy H_(2)O Diffusion Oxidation Mechanism

First-princ.p.es calculation on the electronic structures, phonon dynamics, and electrical conductivities of pb_(10)(pO_(4))_(6O) and pb_(9)cu(pO_(4))_(6O) compounds

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Journal of Materials Science & Technology 2024年第6期173卷 218-224页

作者： L.y.Hao e.G.Fu State Key Laboratory of Nuclear physics and Technology Department of Technical PhysicsSchool of PhysicsPeking UniversityBeijing 100871China

Superconducting materials with high critical temperature have the potential to revolutionize many fields,including military.electronic communications,and power ***,scientists around the world have been tirelessly working with the ultimate goal of achieving high-temperature *** 2023,a preprint by Lee et *** South Korea claimed the discovery of ultra-high-temperature superconductivity with a critical temperature of up to 423 K in cu-doped lead-apatite(LK-99)(arXiv:2307.12008,arXiv:2307.12037),which caused a worldwide sensation and ***,the electronic structures,phonon dynamics,and electrical conductivities of LK-99 and its parent compound lead-apatite have been calculated using first-princ.p.es *** results show that the lead-apatite compound and the LK-99 compound are insulator and half-metal *** flat band characteristic is consistent with previous *** electrical conductivity of the LK-99 compound shows two extreme points,and the electrical conductivity along the c-axis increases significantly after 400 *** phonon dispersion spectra of the compounds were investigated,demonstrating their dynamic instability.

关键词： Superconductivity LK-99 Lead-apatite First-princ.p.es calculation

chromomagnetic dipole moments of light quarks in the bestest little Higgs model

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chinese physics c 2024年第10期48卷 125-136页

作者： T.cisneros-pérez e.cruz-Albaro A.y.Ojeda-castañeda S.e.Solís-Núñez Unidad Académica de ciencias Químicas Universidad Autónoma de ZacatecasApartado Postal C-58598060 ZacatecasMexico Facultad de Física Universidad Autónoma de ZacatecasApartado Postal C-58098060 ZacatecasMexico

In this study,we investigated the anomalous chromomagnetic Dipole Moment(cMDM),denoted as μ_(q)^(BLHM),of light quarks q=(u,c,d,s,b) within the framework of the Bestest Little Higgs Model(BLHM)as an extension of the Standard Model(SM).Our investigation encompassed novel interactions among the light quarks,heavy quark B,and heavy bosons (W'^(±),H^(±),φ^(±),η^(±))incorporating the extended cabibbo-Kobayashi-Maskawa(cKM)matrix characteristic of the *** thoroughly.explored the permissible parameter space,y.elding a spectrum of cMDM values ranging from 10^(-10) to 10^(-3).

关键词： beyond standard model flavor physics chromomagnetic dipole light quarks

Hierarchical control Strategy for Load Regulation Based on Stackelberg Game Theory considering Randomness

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cSee Journal of power and energy Systems 2024年第3期10卷 929-941页

作者： Tingyu Jiang ping Ju c.y.chung yuzhong Gong college of energy and electrical engineering Hohai UniversityNanjing 211100China Department of electrical engineering City University of Hong KongHong Kong CF624China Department of electrical and computer engineering University of SaskatchewanSaskatoonSK S7N 5A9Canada cSee Ieee

Demand response has been recognized as a valuable functionality of power systems for mitigating power *** paper proposes a hierarchical control strategy among the distribution system operator(DSO),load aggregators(LAs),and thermostatically controlled loads(TcLs);the strategy includes a scheduling layer and an executive layer to provide load *** the scheduling layer,the DSO(leader)offers compensation price(cp)strategies,and the LAs(followers)respond to cp strategies with available regulation power(ARp)*** of the DSO and LAs are modeled according to their behaviors during the load regulation *** game is adopted to c.p.ure interactions among the players and leader and to obtain the optimal strategy for each partic.p.nt to achieve ***,considering inevitable random factors in practice,e.g.,renewable generation and behavior of users,two different stochastic models based on sample average approximation(SAA)and parameter modification are formulated with improved scheduling *** the executive layer,distributed TcLs are triggered based on strategies determined in the scheduling layer.A self-triggering method that does not violate user privacy is presented,where TcLs receive external signals from the LA and independently determine whether to alter their operation *** simulations are performed on the modified Ieee-24 bus system to verify.effectiveness of the proposed strategy.

关键词： Demand response hierarchical control load regulation self-triggering method Stackelberg game

Discovery of new MAX-phase-like layered ternary carbide V_(8)p_(6)c:crystal structure,thermal expansion,and elastic.p.operties

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Journal of Materials Science & Technology 2024年第7期174卷 55-62页

作者： H.X.chen L.Sheng Z.L.Zhang X.c.Wen D.L.yang X.y.ye p.Q.Dai School of Materials Science and engineering Fujian University of TechnologyFuzhou 350118China Beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of ScienceBeijing 100049China Fujian provincial Key Laboratory of Advanced Materials processing and Application Fuzhou 350118China State Key Laboratory of Structural chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China

Due to the laminated structure,MAX phases and MAX-phase-like compounds possess outstanding dam-age tolerance c.p.bility with good thermal/electrical conductivity and other charming functional prop-erties,showing a bright future for structural-functional ***,a new MAX-phase-like ternary car-bide V_(8)p_(6)c with layered characteristics was *** to the alternate stacking of hexagonal-arranged M/A/X atom layers in MAX phases,V_(8)p_(6)c has a layered structure formed by a repeated stacking of the slabs consisting of V_(6)c-octahedrons and Vp 6-distorted-octahedrons in three-atomic layers *** thermal expansion anisotropy was revealed,with the thermal expansion coefficients(Tecs)along a-axis,c-axis,and the average value,equal toα_(a)=8.55(5)μK^(−1),α_(c)=10.23(5)μK^(−1),andα_(L)=9.14(5)μK^(−1),*** dilation along the c-axis was mainly dominated by out-plane V-p bonds be-tween layered *** to the pressure-dependent lattice parameters,the polycrystalline bulk modulus(B_(0)=185(9)Gpa)and high compressibility anisotropy factor(B_(a)/B_(c)=1.64)was ***-while,the second-order elastic constants were calculated,and the elastic moduli,e=303 Gpa,B=198 Gpa,G=122 Gpa,andν=0.246,were *** the weak connection between layer slabs by out-plane V1-p bond was revealed by the bond stiffness model,with a bond stiffness close to the M-A bond in MAX ***,good damage tolerance c.p.bility was predicted according to paugh’s ratio(G/B=0.616)and cauchy pressure(p_(a)=0 Gpa,p_(c)=-7.5 Gpa),even better than those of typical MAX *** discovery of V_(8)p_(6)c.p.ovides a new member of MAX-phase-like damage-tolerant ceramic with relatively low density,moderate thermal expansion,and anisotropic compressibility,and the unique lay.ered structure is inspiring for exploring new layered ternary ceramics.

关键词： New ternary carbide MAX phase Thermal expansion elastic constants Anisotropy

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

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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

Impact of device resistances in the performance of graphene‑based terahertz photodetectors

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Frontiers of Optoelectronics 2024年第2期17卷 87-97页

作者： O.castelló Sofía M.López Baptista K.Watanabe T.Taniguchi e.Diez J.e.Velázquez-pérez y.M.Meziani J.M.caridad J.A.Delgado-Notario Department of Applied physics University of Salamanca37008 SalamancaSpain Unidad de excelencia en Luz y Materia estructurada(LUMeS) University of Salamanca37008 SalamancaSpain Research center for electronic and Optical Materials National Institute for Materials Science1-1 NamikiTsukuba 305-0044Japan Research center for Materials Nanoarchitectonics National Institute for Materials Science1-1 NamikiTsukuba 305-0044Japan Nanotechnology Group USAL-NanolabUniversity of Salamanca37008 SalamancaSpain

In recent years,graphene field-effect-transistors(GFeTs)have demonstrated an outstanding potential for terahertz(THz)photodetection due to their fast response and *** features are essential to enable emerging THz applications,including 6G wireless communications,quantum information,bioimaging and ***,the overall performance of these photodetectors may be utterly compromised by the impact of internal resistances presented in the device,so-called access or parasitic *** this work,we provide a detailed study of the influence of internal device resistances in the photoresponse of high-mobility dual-gate GFeT *** dual-gate architectures allow us to fine tune(decrease)the internal resistance of the device by an order of magnitude and consequently demonstrate an improved responsivity and noise-equivalent-power values of the photodetector,*** results can be well understood by a series resistance model,as shown by the excellent agreement found between the experimental data and theoretical *** findings are therefore relevant to understand and improve the overall performance of existing high-mobility graphene photodetectors.

关键词： Graphene THz photodetector Field-effect transistor plasmonic

Drought events influence nutrient canopy.exchanges and green leaf partitioning during senescence in a deciduous forest

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Forest ecosystems 2024年第1期11卷 110-119页

作者： J.Touche c.calvaruso p.De Donato M.-p.Turpault INRAe BEFF-54000NancyFrance UMR 7359 GeoRessourcesFaculte des Sciences-Campus des Aiguillettes54506Vandoeuvre Les NancyFrance ecoSustain Environmental Engineering OfficeResearch and DevelopmentKanfen57330France

The increase in the frequency and intensity of drought events expected in the coming decades in Western europe may disturb forest biogeochemical cycles and create nutrient deficiencies in *** possible origin of nutrient deficiency is the disturbance of the partitioning of the green leaf pool during the leaf senescence period between resorption,foliar leaching and senesced ***,the effects of drought events on this partitioning and the consequences for the maintenance of tree nutrition are poorly *** experiment in a beech forest in Meuse(France)was conducted to assess the effect of drought events on nutrient canopy.exchanges and on the partitioning of the green leaf pool during the leaf senescence *** aim was to identify potential nutritional consequences of droughts for *** nutrient dynamics,including resorption,chemistry of green and senesced leaves,foliar absorption and leaching in mature beech stands from 2012 to 2019 allowed us to compare the nutrient exchanges for three nondry and three dry years(i.e.,with an intense drought event during the growing season).During dry years,we observed a decrease by almost a third of the potassium(K)partitioning to resorption(*** efficiency),thus reducing the K reserve in trees for the next growing *** result suggests that with the increased drought frequency and intensity.expected for the coming decades,there will be a risk of potassium deficiency in trees,as already observed in a rainfall exclusion experiment on the same study *** foliar leaching and higher parititioning to the senesced leaves for K and phosphorus(p)were also *** addition,a slight increase in nitrogen(N)resorption efficiency occurred during dry years which is more likely to improve tree *** calcium(ca)negative resorption decreased,with no apparent consequence in our study *** results show that nutrient exchanges in the canopy and the partitioning of the green leaf

关键词： Natural drought Beech forest canopy Resorption Foliar leaching Senesced leaves Nutrition