This laboratory portrait is drawn to give a general view of the research and education on nuclearphysics and technology at Peking University. Since Peking University (PKU) is the eldest and also one of the most prest...
The intelligent control of accelerator particle beams,achieved through machine learning,offers a new opportunity for the design and regulation of high-power,high-intensity *** recent years,this technology has been app...
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The intelligent control of accelerator particle beams,achieved through machine learning,offers a new opportunity for the design and regulation of high-power,high-intensity *** recent years,this technology has been applied in several practical *** instance,the DeepMind team successfully used reinforcement learning to control the plasma in a Tokamak device with 19 control magnets[1].
We propose a novel criterion to identify the first-order QCD phase transition and the critical end-point (CEP) via directly the netproton number fluctuations measured in relativistic heavy-ion collision (RHIC) *** thi...
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We propose a novel criterion to identify the first-order QCD phase transition and the critical end-point (CEP) via directly the netproton number fluctuations measured in relativistic heavy-ion collision (RHIC) *** this method,we show that there has not yet been a direct signal of the CEP of QCD according to the currently available data accumulated in the beam energy scan experiments with ■.However,there is still a possibility for the CEP to appear in the matter generated by the collisions with energy below 7.7 Ge V,and its identification requires future measurements with high statistics for the high-order cumulants at low collision energies.
A state-of-the-art detector array with a digital data acquisition system has been developed for charged-particle decay studies,includingβ-delayed protons,αdecay,and direct proton emissions from exotic proton-rich **...
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A state-of-the-art detector array with a digital data acquisition system has been developed for charged-particle decay studies,includingβ-delayed protons,αdecay,and direct proton emissions from exotic proton-rich *** digital data acquisition system enables precise synchronization and processing of complex signals from various detectors,such as plastic scintillators,silicon detectors,and germaniumγ*** system's performance was evaluated using theβdecay of^(32)Ar and its neighboring nuclei,produced via projectile fragmentation at the first Radioactive Ion Beam Line in Lanzhou(RIBLL1).key measurements,including the half-life,charged-particle spectrum,andγ-ray spectrum,were obtained and compared with previous results for *** the implantation–decay method,the isotopes of interest were implanted into two doublesided silicon strip detectors,where their subsequent decays were measured and correlated with preceding implantations using both position and time *** detection system has potential for further applications,including the study ofβ-delayed charged-particle decay and direct proton emissions from even more exotic proton-rich nuclei.
Nanostructured materials have demonstrated superior radiation-damage tolerance compared to their coarse-grained counterparts,contributing to the extended lifespan of nuclear ***,the mechanisms underlying this enhanced...
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Nanostructured materials have demonstrated superior radiation-damage tolerance compared to their coarse-grained counterparts,contributing to the extended lifespan of nuclear ***,the mechanisms underlying this enhanced irradiation resistance remain *** this study,we present atomistic simulations to investigate the impact of Cu/W heterophase interface on the evolution of irradiation-induced *** simulation results reveal that the Cu/W interfaces can act as defect sinks,effectively trapping self-interstitial atoms(SIAs).Furthermore,the interface demonstrates both the interstitial emission and interstitial transfer mechanisms,wherein the trapped W SIAs facilitate the emission of Cu atoms from the interface to the Cu *** emitted Cu SIAs can promote defect recombination on the Cu side,leading to a reduced defect concentration in the Cu/W ***,these combined mechanisms contribute to a lower overall concentration of irradiation-induced defect,thereby enhancing the radiation resistance of Cu/W nanomultilayers.
The isospin asymmetry and quadrupole deformation value of drip-line nuclei are investigated using the Weizsäcker-Skyrme nuclear mass *** observe that for heavy nuclei at the neutron drip line,the Coulomb energy h...
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The isospin asymmetry and quadrupole deformation value of drip-line nuclei are investigated using the Weizsäcker-Skyrme nuclear mass *** observe that for heavy nuclei at the neutron drip line,the Coulomb energy heightened by an aug-mented charge could not be mitigated completely by symmetry energy because of isospin asymmetry saturation but is resisted complementally by strong nuclear *** positions of saltation for the difference in proton numbers between two neighboring nuclei at the neutron drip line,and the isospin asymmetry of the neutron drip-line nucleus as a function of the neutron number distinctly correspond to the known magic numbers,which can serve as a reference to verify the undeter-mined neutron magic *** fitting of the binding energy difference between mirror nuclei(BEDbMN),a set of Coulomb energy coefficients with greater accuracy is obtained.A high-precision description of the BEDbMN is useful for accurately determining the experimentally unknown mass of the nucleus close to the proton drip line if the mass of its mirror nucleus is measured experimentally.
Based on the Skyrme energy density functional and reaction Q-value,this study proposed an effective nucleus-nucleus poten-tial for describing the capture barrier in heavy-ion fusion *** 443 extracted barrier heights w...
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Based on the Skyrme energy density functional and reaction Q-value,this study proposed an effective nucleus-nucleus poten-tial for describing the capture barrier in heavy-ion fusion *** 443 extracted barrier heights were well reproduced with a root-mean-square(RMS)error of 1.53 MeV,and the RMS deviations with respect to 144 time-dependent Hartree-Fock capture barrier heights were only 1.05 *** with the Siwek-Wilczyński formula,wherein three parameters were determined by the proposed effective potentials,the measured capture cross sections at energies around the barriers were reasonably well reproduced for several fusion reactions induced by nearly spherical nuclei as well as by nuclei with large deformations,such as^(154)Sm and^(238)*** shallow capture pockets and small values of the average barrier radii resulted in the reduction of the capture cross sections for 52,54Cr-and 64 Ni-induced reactions,which were related to the synthesis of new super-heavy nuclei.
The observed low-lying K=5/2^(±) positive-and negative-parity bands in the stable nucleus ^(153)Eu are investigated using the reflection-asymmetric triaxial particle rotor *** experimental energy spectra,energy s...
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The observed low-lying K=5/2^(±) positive-and negative-parity bands in the stable nucleus ^(153)Eu are investigated using the reflection-asymmetric triaxial particle rotor *** experimental energy spectra,energy staggering parameters,and intraband E2 and M1 transition probabilities are well *** calculated interband B(E1)values are found to depend sensitively on the octupole deformation parameter β_(30),although the energy spectra and intraband E2 and M1 transitions can be reproduced without the octupole degree of *** observed enhanced E1 transition probabilities can be reproduced with β_(30)=*** detailed analysis of the intrinsic wave functions shows these nearly degenerate positive-and negative-parity bands are built on two individual proton configurations,i.e.,dominated by πg_(7/2)[Ω=5/2]and πh_(11/2)[Ω=5/2],respectively,which differs from the parity doublet bands built on a single parity-mixed configuration.
This study investigated the tetrahedral structure in^(80)Zr and Lambda(Λ)impurity effect in^(81)ΛZr using the multidimensionally constrained relativistic Hartree-Bogoliubov *** ground states of both^(80)Zr and^(81)...
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This study investigated the tetrahedral structure in^(80)Zr and Lambda(Λ)impurity effect in^(81)ΛZr using the multidimensionally constrained relativistic Hartree-Bogoliubov *** ground states of both^(80)Zr and^(81)ΛZr exhibit a tetrahedral configuration,accompanied by prolate and axial-octupole shaped *** calculations reveal that there are changes in the deformation parametersβ20,β30,andβ32 uponΛbinding to^(80)Zr,except forβ32 whenΛoccupies *** to the two shape isomers,theΛparticle exhibits weaker binding energy in the tetrahedral state when occupying the 1/2+[000](Λs)or 1/2−[110]single-particle *** contrast,the strongest binding occurs for theΛparticle in the 1/2−[101]state with tetrahedral ***,a largeΛseparation energy may not necessarily correlate with a significant overlap between the density distributions of theΛparticle and nuclear core,particularly for tetrahedral hypernuclei.
The strain-induced crystallization behaviors of ultrasonic micro-injection molded poly(L-lactic acid)/poly(D-lactic acid)(PLLA/PDLA)samples from an amorphous state were investigated by stress-strain relations and in s...
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The strain-induced crystallization behaviors of ultrasonic micro-injection molded poly(L-lactic acid)/poly(D-lactic acid)(PLLA/PDLA)samples from an amorphous state were investigated by stress-strain relations and in situ wide angle X-ray diffraction(WAXD) *** formation of direct strain-induced stereocomplex(SC) was *** samples molded at 50 and 80 °C,this phenomenon can be attributed to the acceleration of the ordered structures due to the existence of a large number of SC *** SC nuclei are assumed to serve as the transient physical cross-links to initiate the strain-induced *** onset of strain-induced crystallization is analogous to the heating induced structural ***,the observed strain-induced SC process can be considered a pseudo process,which is actually thermally *** further stretching,the actual strain-induced crystallization occurs with the exclusive formation of the homocrystallite(HC),while the preceding formed SC crystals undergo slight fragmentation during subsequent tensile *** 120 °C,due to the reduced number of SC nuclei within the sample,the occurrence of cold crystallization during stretching plays a more significant role than SC nuclei with respect to the strain-induced SC process,as demonstrated by in situ WAXD measurements upon annealing in both the static and stretched states.
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