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Impact of the Brink-Axel hypothesis on unique first-forbiddenβ-transitions for r-process nuclei

chinese Physics c 2024年第3期48卷 148-168页

作者： Fakeha Farooq Jameel-un nabi Ramoona Shehzadi Department of Physics University of the PunjabQuaid-e-Azam Campus 54590LahorePakistan university of Wah Quaid AvenueWah Cantt 47040PunjabPakistan

Key nuclear inputs for the astrophysical r-process simulations are the weak interaction ***,the accuracy of these inputs directly affects the reliability of nucleosynthesis *** majority of the stellar rates,used in simulation studies are calculated by invoking the Brink-Axel(BA)*** BA hypothesis assumes that the strength functions of all parent excited states are the same as for the ground state,only shifted in ***,the BA hypothesis has to be tested against microscopically calculated state-by-state *** this project,we study the impact of the BA hypothesis on calculated stellarβ^(-)-decay and electron capture *** investigation include both unique first forbidden(U1F)and allowed transitions for 106 neutron-rich trans-iron nuclei([27,77]≤[Z,A]≤[82,208]).The calculations were performed using the deformed proton-neutron quasiparticle random-phase approximation(pn-QRPA)model with a simple plus quadrupole separable and schematic ***-point and several key r-process nuclei lie within the considered mass region of the nuclear *** computed electron capture andβ^(-)-decay rates using two different prescriptions for strength *** was based on invoking the BA hypothesis and the other was the state-by-state calculation of strength functions,under stellar density and temperature conditions([10,1]≤[ρYe(g/cm^(3)),T(GK)]≤[10^(11),30]).Our results show that the BA hypothesis invoked U1Fβ^(-)rates are overestimated by 4–5 orders of magnitude as compared to microscopic *** capture rates,more than two orders of magnitude differences were noted when applying the BA *** was concluded that the BA hypothesis is not a reliable approximation,especially forβ^(-)-decay forbidden transitions.

关键词： Brink-Axel hypothesis pn-QRPA model unique first forbiddenβ-transitions GT strength functions trans-iron nuclei r-process

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Progress in preparation of Aln-reinforced magnesium matrix composites:A review

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china Foundry 2024年第1期21卷 1-10页

作者： lu chen Shu-lin lü Di-jia Zhao Wei Guo Jian-yu li Shu-sen Wu State Key lab of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

As a ceramic material,Aln has very good thermophysical and mechanical *** addition,Aln is an effective refining agent for Mg alloys because it has a lattice constant similar to that of ***,Aln is an ideal reinforcement for magnesium matrix composites(MMcs),and is attracting increasing *** review addresses the development of preparation technologies for Aln-reinforced Mg matrix *** mainstream preparation techniques include stir casting,melt infiltration,powder metallurgy,and in-situ *** addition,the advantages and disadvantages of these techniques are analyzed in depth,and it is pointed out that the next direction for the preparation of high-performance Aln-reinforced MMcs is less aluminization and multiple technologies integration.

关键词： Aln MMcs preparation thermophysical property mechanical property

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Radiative capture of proton through the ^(14)n(p,γ)^(15)O reaction at low energy

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chinese Physics c 2024年第4期48卷 183-192页

作者： B.F.Irgaziev Abdul Kabir Jameel-un nabi national university of Uzbekistan Tashkent 100174Uzbekistan Space and Astrophysics Research lab National Centre of GIS and Space ApplicationsDepartment of Space ScienceInstitute of Space TechnologyIslamabad 44000Pakistan university of Wah Quaid AvenueWah Cantt 47040PunjabPakistan

The cnO cycle is the main source of energy in stars more massive than our *** process defines the energy production,the duration of which can be used to determine the lifetime of massive *** cycle is an important tool for determining the age of globular *** proton capture via p+^(14)n→^(15)O+γ,at energies of astrophysical interest,is an important process in the cnO *** this project,we apply a potential model to describe both non-resonant and resonant reactions in the channels where radiative capture occurs through electric E1 *** employed the R-matrix method to describe the ongoing reactions via M1 resonant transitions,when it was not possible to correctly reproduce the experimental data using the potential *** partial components of the astrophysical S-factor are calculated for all possible electric and magnetic dipole transitions in ^(15)*** linear extrapolated S-factor at zero energy(S(0))agrees well with earlier reported values for all transition types considered in this *** on the value of the total astrophysical S-factor,depending on the collision energy,we calculate the nuclear reaction rates for p+^(14)n→^(15)O+γ.The computed rates agree well with the results reported in the nAcRE II collaboration and most recent existing measurements.

关键词： cnO cycle potential model R-matrix method cross-section astrophysical S-factor nuclear rates.

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Empirical model for fusion cross sections of ca-induced reactions

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chinese Physics c 2024年第3期48卷 126-132页

作者： Reddi Rani.l n.Sowmya K.n Sridhar H c.Manjunatha M.M.Armstrong Arasu Department of Physics St.Joseph's College(Autonomous)Affiliated to Bharathidasan UniversityTiruchirappalli620002TNIndia Department of Physics Govt.First.Grade CollegeChikkaballapur-562101KarnatakaIndia Department of Physics Govt.First.Grade CollegeMalur-563160KarnatakaIndia Department of Physics Govt.First.Grade CollegeDevanahalli-562110KarnatakaIndia

A new empirical formula for the astrophysical S-factor has been suggested as a function of the coulomb interaction parameter,center of mass energy,and barrier *** 22 fusion reactions with ^(40,48)ca as projectiles were considered for different targets,leading to compound nuclei with atomic and mass numbers varying between 40≤Z≤≤Z≤112 and 88≤A≤27888≤A≤278,*** fusion cross-sections have been estimated using the geometric factor,the Gamow-Sommerfield factor,and the empirical formula for the *** study's findings showed better agreement with those of available experiments when compared to Wong's *** present work leads to a smaller standard deviation value than Wong's formula when used to correlate the experimental data of calcium-induced fusion ***'s formula provides a good approximation of fusion cross-sections when the center of mass energy is below the fusion barrier when compared to above the fusion barrier.

关键词： fusion cross-sections Wong formula Gamow-Sommerfield-factor Geometric-factor S-factor

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Effect of characteristics and distribution of Mg_(17)Al_(12)precipitates on tensile and bending properties of high-Al-containing Mg alloys

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Journal of Magnesium and Alloys 2024年第2期12卷 779-793页

作者： Sumi Jo Gyo Myeong lee Jong un lee Young Min Kim Sung Hyuk Park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Department of Magnesium Korea Institute of Materials ScienceChangwon 51508Republic of Korea

This study investigates the effect of characteristics and distribution of Mg_(17)Al_(12)precipitates on the uniaxial tensile and three-point bending properties of extruded Mg alloys containing high Al *** extruded Mg–9Al–1Zn–0.3Mn(AZ91)alloy contains lamellar-structured Mg_(17)Al_(12)discontinuous precipitates along the grain boundaries,which are formed via static precipitation during natural air *** extruded Mg–11Al–1Zn–0.3Mn(AZ111)alloy contains spherical Mg_(17)Al_(12)precipitates at the grain boundaries and inside the grains,which are formed via dynamic precipitation during *** to inhomogeneous distribution of precipitates,the AZ111 alloy consists of two different precipitate regions:precipitate-rich region with numerous precipitates and finer grains and precipitate-scarce region with a few precipitates and coarser *** AZ111 alloy exhibits a higher tensile strength than the AZ91 alloy because its smaller grain size and more abundant precipitates result in stronger grain-boundary hardening and precipitation hardening effects,***,the tensile elongation of the AZ111 alloy is lower than that of the AZ91 alloy because the weak cohesion between the dynamic precipitates and the matrix facilitates the crack initiation and *** bending,a macrocrack initiates on the outer surface of bending specimen in both *** AZ111 alloy exhibits higher bending yield strength and lower failure bending strain than the AZ91 *** bending specimens of the AZ91 alloy have similar bending formability,whereas those of the AZ111 alloy exhibit considerable differences in bending formability and crack propagation behavior,depending on the distribution and number density of precipitates in the *** bending specimens of the AZ111 alloy,it is found that the failure bending strain(ε_(f,bending))is inversely proportional to the area fraction of precipitates in the outer zone of bending specimen(A_(ppt)),with a relation

关键词： Mg–Al alloy Extrusion Bending Precipitation Microstructure

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Re-analysis of temperature dependent neutron capture rates and stellarβ-decay rates of^(95-98)Mo

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chinese Physics c 2024年第9期48卷 142-149页

作者： Abdul Kabir Jameel-un nabi Muhammad Tahir Abdul Muneem Zain Ul Abideen Space and Astrophysics Research lab National Centre of GIS and Space ApplicationsDepartment of Space ScienceInstitute of Space TechnologyIslamabad 44000Pakistan university of Wah Quaid AvenueWah Cantt 47040PunjabPakistan Faculty of Engineering Sciences GIK Institute of Engineering Sciences and TechnologyTopi 23640Khyber PakhtunkhwaPakistan

The neutron capture rates and temperature dependent stellar beta decay rates of Mo isotopes are investigated within the framework of the statistical code TAlYS v1.96 and the proton neutron quasi particle random phase approximation(pn-QRPA)*** Maxwellian average cross-section(MAcS)and neutron capture rates for the^(95-98)Mo(n,γ)^(96-99)Mo radiative capture process are analyzed within the framework of the statistical code TAlYS v1.96 based on the phenomenological nuclear level density model and gamma strength *** present model-based computations for the MAcS are comparable to the existing measured *** sensitivity of stellar weak interaction rates to various densities and temperatures is investigated within the framework of the pn-QRPA *** attention is paid to the impact of thermally filled excited states in the decaying nuclei(^(95-98)Mo)on electron emission and positron capture ***,we compare the neutron capture rates and stellar beta decay *** is found that neutron capture rates are higher than stellar beta decay rates at both lower and higher temperatures.

关键词： cross-section TAlYS nuclear level density decay rates capture rates

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cr-induced fusion reactions to synthesize superheavy elements

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nuclear Science and Techniques 2024年第5期35卷 122-130页

作者： S.Madhu H.c.Manjunatha n.Sowmya B.M.Rajesh l.Seenappa R.S.Susheela Department of Physics R V College of EngineeringBangalore 560074India Visvesvaraya Technological university BelagaviKarnataka 590018India Department of Physics Government First Grade CollegeSrinivasapurKarnataka 563135India Department of Physics Government First Grade CollegeDevanahallyKarnataka 562110India Department of Physics Government First Grade CollegeMulbagalKarnataka 563131India Department of Physics Government First Grade collegeNanjangudOoty RoadMysore 571301India

We investigated ^(50,52-54)cr-induced fusion reactions for the synthesis of the superheavy element in the 104≤Z≤122 *** cross sections produced in this investigation using ^(54)cr projectiles were compared with those obtained in prior *** estimated cross sections from this analysis are consistent with the findings of prior *** the current study,the predicted cross section was found to be 42fb at 236 MeV for ^(53)cr+^(243)Am,23.2 fb at 236 MeV for ^(54)cr+^(247)cm,95.6 fb at 240 MeV for ^(53)cr+248Bk,and 1.33 fb at 242 MeV for ^(53)cr+***,these projected cross sections with excitation energy and beam energy will be useful in future cr-induced fusion reaction investigations.

关键词： Fusion cross sections compound nucleus formation probability Survival probability Evaporation residue cross sections

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Efficient guiding and focusing of intense laser pulse using periodic thin slits

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Matter and Radiation at Extremes 2024年第4期9卷 29-39页

作者： l.Xu T.W.Huang K.Jiang c.n.Wu H.Peng P.c.hen R.li H.B.Zhuo c.T.Zhou Shenzhen Key laboratory of Ultraintense laser and Advanced Material Technology Center for Intense Laser ApplicationTechnologyand College of Engineering PhysicsShenzhen Technology UniversityShenzhen 518118People’s Republic of China

Slits have been widely used in laser-plasma interactions as plasma optical components for generating high-harmonic light and controlling laser-driven particle ***,we propose and demonstrate that periodic thin slits can be regarded as a new breed of optical elements for efficient focusing and guiding of intense laser *** fundamental physics of intense laser interaction with thin slits is studied,and it is revealed that relativistic effects can lead to enhanced laser focusing far beyond the pure diffractive focusing *** addition,the interaction of an intense laser pulse with periodic thin slits makes it feasible to achieve multifold enhancement in both laser intensity and energy transfer efficiency compared with conventional *** results provide a novel method for manipulating ultra-intense laser pulses and should be of interest for many laser-based applications.

关键词： laser pulse intense

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Imprints of a gravitational wave through the weak field deflection of photons

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chinese Physics c 2024年第8期48卷 240-245页

作者： Reggie c.Pantig Ali Övgün Physics Department Mapúa University658 Muralla St.IntramurosManila 1002Philippines Physics Department Eastern Mediterranean UniversityFamagusta99628 North Cyprusvia Mersin 10Turkiye

In this study,we investigate the novel phenomenon of gravitational lensing experienced by gravitational waves traveling past a Schwarzschild black hole perturbed by a specific,first-order,polar gravitational *** apply the Gauss-Bonnet theorem,finding a topological contribution to the deflection of light rays passing near the black *** demonstrate that the deflection angle can be determined by analyzing a region entirely outside the path of the light ray,leading to a calculation based solely on the parameters of the perturbing wave(legendre polynomial order,l;frequency,σ).This approach offers a unique perspective on gravitational lensing and expands our understanding of black hole interactions with gravitational waves.

关键词： supermassive black holes gravitational waves chaos weak deflection angle Gauss-Bonnet theorem

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Effect of radiative loss mechanisms on FIR thermometric parameters of nd^(3+)-doped lithium tellurite glasses

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Journal of Rare Earths 2024年第7期42卷 1250-1257,I0002页

作者： c.Y.Morassuti A.P.l Silva l.A.O.nunes S.M.lima l.H.c.Andrade Optical and Photothermal Spectroscopy Group(GEOF) Center for Studies in Natural Resources(CERNA)State University of Mato Grosso do Sul(UEMS)C.P.351DouradosMSBrazil Renato Archer Information Technology center Dom Pedro I Highway(SP-65)Km 1436-Chácaras Campos dos AmaraisCampinasSPBrazil Institute of Physics of São carlos University of São PauloSão CarlosSPBrazil

nd^(3+)-doped tellurite glasses are promising materials for thermometers based on the fluorescence intensity ratio(FIR)***,at high nd^(3+)concentrations,energy transfer(ET)processes such as optical reabsorption and cross-relaxation can affect the nd^(3+)emission,which has been little explored in the ***,the present work investigated the use of nd^(3+)-doped tellurite glass(samples doped with nd^(3+)at 0.2 mol%,0.5 mol%,2.0 mol%,and 4.0 mol%)in fluorescence thermometers,in the temperature range from 299 to 371 *** results indicate a strong dependence of the FIR parameters on the nd^(3+)concentration,due to changes in the emission band profiles caused by optical reabsorption of the nd^(3+)emissions and cross-relaxation processes.A decrease of the relative sensitivity of the ratio^(4)F_(5/2)→^(4)I_(9/2)/^(4)F_(3/2)→^(4)I_(9/2)is observed for samples doped with higher amounts of nd^(3+).The maximum relative sensitivity at 299 K is 3.00%/K,which is the highest value among the reported nd^(3+)ions.

关键词： nd^(3+)-doped tellurite glass Fluorescence intensity ratio Optical thermometry Judd-Ofelt Rare earths

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