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To study the β -delayed neutron decay of nuclei far from β stability line, a new β -delayed neutron detection system working with the continuous beam mode has been built at Peking University and tested with radioactive ion beams . To get fast timing signal for neutron Time-of-Flight (ToF) measurement and good spatial correlation between the implanted particles and the subsequent β particles, a double-sided silicon detector is sandwiched between two thin plastic scintillators , which constitute the implantation and β detection array. According to the test measurements with radioactive ion beams, this detection system has a high β coincident detection efficiency of 30 . 7 ( 5 ) % with much less disturbance from other unstable nuclei and the random background. After the time-walk correction and the flight path calibration, good energy resolution based on neutron ToF measurement can be obtained. The properties of this detection system make the study of β -delayed neutron decay of nuclei with very low beam intensity feasible.

A resonant state at 3.21-0.04+0.12MeV, located just above the one-neutron separation threshold, was observed for the first time in Be12 from the Be11(d,p)Be12 one-neutron transfer reaction in inverse kinematics. This state is assigned a spin-parity of 0- according to the systematics of the level scheme of the N=8 isotones and decay-width analysis. Gamow coupled-channel and Gamow shell-model calculations show the importance of the continuum coupling, which dramatically influences the excitation energy and ordering of low-lying states. Various exotic structures associated with cross-shell intruding configurations in Be12 and in its isotonic nucleus Li11 are comparably discussed.

A kinematically complete quasifree (p,pn) experiment in inverse kinematics was performed to study the structure of the Borromean nucleus ^{17}B, which had long been considered to have a neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for 1s_{1/2} and 0d_{5/2} orbitals, and a surprisingly small percentage of 9(2)% was determined for 1s_{1/2}. Our finding of such a small 1s_{1/2} component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in ^{17}B. The present work gives the smallest s- or p-orbital component among known nuclei exhibiting halo features and implies that the dominant occupation of s or p orbitals is not a prerequisite for the occurrence of a neutron halo.

8 pags., 4 figs., 3 tabs., The nuclear structure of 51Ar, an uncharted territory so far, was studied by the (p,2p) reaction using γ-ray spectroscopy for the bound states and the invariant mass method for the unbound states. Two peaks were detected in the γ-ray spectrum and six peaks were observed in the 50Ar+n relative energy spectrum. Comparing the results to our shell-model calculations, two bound and six unbound states were established. Three of the unbound states could only be placed tentatively due to the low number of counts in the relative energy spectrum of events associated with the decay through the first excited state of 50Ar. The low cross sections populating the two bound states of 51Ar could be interpreted as a clear signature for the presence of significant subshell closures at neutron numbers 32 and 34 in argon isotopes. It was also revealed that due to the two valence holes, unbound collective states coexist with individual-particle states in 51Ar., We are very grateful to the RIKEN Nishina Center accelerator staff for providing the stable beam and to the BigRIPS team for the smooth operation of the secondary beams. The development of the MINOS device has been supported by the European Research Council through the ERC Grant No. MINOS-258567. F. B. was supported by the RIKEN Special Postdoctoral Researcher Program. K. O. acknowledges the support by Grant-in-Aid for Scientific Research JP16K05352. Y. U. acknowledges the support by Grant-in-Aid for Scientific Research 20K03981. Y. L. S. acknowledges the support of Marie Skłodowska-Curie Individual Fellowship (H2020-MSCA-IF-2015-705023) from the European Union and the support from the Helmholtz International Center for FAIR. H. N. L. acknowledges the support from the Enhanced Eurotalents program (PCOFUND-GA-2013-600382) co-funded by CEA and the European Union. T. A., C. L., D. R., H. T., V. W., L. Z., H. N. L., V. W. and A. O. acknowledge the support from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) Project No. 279384907-SFB 1245. R. B. G. acknowledges the support from the DFG under Grant No. BL 1513/1-1. Y. L. S. and A. O. acknowledge the support from the Alexander von Humboldt Foundation. B. D. L. and L. X. C. acknowledge the support from the Vietnam Ministry of Science and Technology under Grant No. ĐTCB.01/21/VKHKTHN. I. G. has been supported by HIC for FAIR and HRZZ under project No. 1257 and 7194. K. I. H., D. K. and S. Y. P. acknowledge the support from the NRF grant funded by the Korea government (No. 2017R1A2B2012382 and 2019M7A1A1033186). F. B. acknowledge the support from the RIKEN Special Postdoctoral Researcher Program. D. S. and Z. E. were supported by projects No. GINOP-2.3.3-15-2016-00034 and No. K128947. V. V. acknowledges support from the Spanish Ministerio de Economía y Competitividad under Contract No. FPA2017-84756-C4-2-P. V. W. and P. K. acknowledge the support from BMBF grants 05P15RDFN1 and 05P19RDFN1. P. K. acknowledges support from HGS-HIRe. This work was also supported by NKFIH (114454).

The Borromean halo nucleus 6He has been studied by a kinematically complete measurement of Coulomb and nuclear breakup into α + 2n on Pb and C targets at 70 MeV/nucleon. Fully quantum-mechanical four-body breakup calculations reproduce the energy and angular differential cross sections below E rel ∼ 1 MeV for both targets. The model used here reproduces the 6He ground-state properties as well as α-n and n-n scattering data and predicts an average opening angle 〈 θ n n 〉 of 68∘ between the two halo neutrons. However, the model underestimates the breakup cross sections for higher E rel , indicating a possible contribution from the inelastic breakup. Alternatively, we examine the empirically modified calculations that reproduce the energy-differential cross sections for a wide range of scattering angles for both targets. The extracted B(E1) peaks at E rel ∼ 1.4 MeV and amounts to 1.6(2) e2 fm2 for E rel ≤ 20 MeV, resulting 〈 θ n n 〉 = 56 − 10 + 9 degrees. In either interpretation, the current results show evidence of the dineutron spatial correlation in 6He.

7 pags., 4 figs., 1 tab., Excited states in the N=40 isotone Ti were populated via the V(p,2p)Ti reaction at ∼200 MeV/nucleon at the Radioactive Isotope Beam Factory and studied using γ-ray spectroscopy. The energies of the 2 →0 and 4 →2 transitions, observed here for the first time, indicate a deformed Ti ground state. These energies are increased compared to the neighboring Cr and Fe isotones, suggesting a small decrease of quadrupole collectivity. The present measurement is well reproduced by large-scale shell-model calculations based on effective interactions, while ab initio and beyond mean-field calculations do not yet reproduce our findings. The shell-model calculations for Ti show a dominant configuration with four neutrons excited across the N=40 gap. Likewise, they indicate that the N=40 island of inversion extends down to Z=20, disfavoring a possible doubly magic character of the elusive Ca., We thank the RIKEN Nishina Center accelerator staff and the Bi-gRIPS team for the stable operation of the high-intensity Zn beam and for the preparation of the secondary beam setting. K.O. ac-knowledges the support by Grant-in-Aid for Scientific Research of the Japan Society for the Promotion of Science (JSPS) JP16K05352. A.P. is supported in part by the Ministerio de Ciencia, Innovación y Universidades (Spain), Severo Ochoa Programme SEV-2016-0597 and grant PGC-2018-94583. F.B. is supported by the RIKEN Spe-cial Postdoctoral Researcher Program. L.X.C. and B.D.L. would like to thank the Vietnam Ministry of Science and Technology (MOST) for its support through the Physics Development Program Grant No. ÐTÐLCN.25/18. I.G. has been supported by HIC for FAIR and Croatian Science Foundation under projects no. 1257 and 7194. D. So. was supported by the the European Regional Develop-ment Fund contract No. GINOP-2.3.3-15-2016-00034 and the National Research, Development and Innovation Fund of Hungary via Project No. K128947. V.V. acknowledges support from the Span-ish Ministerio de Economía y Competitividad under Contract No. FPA2017-84756-C4-2-P. K.I.H., D.K. and S.Y.P. acknowledge the sup-port from the National Research Foundation of Korea grant No. 2018R1A5A1025563 and 2019M7A1A1033186. The development of MINOS was supported by the European Research Council through the ERC Grant No. MINOS-258567. This work was also supported by the JSPS KAKENHI Grant No. 18K03639, MEXT as “Priority is-sue on post-K computer” (Elucidation of the fundamental laws and evolution of the universe), the Joint Institute for Computational Fundamental Science (JICFuS), the CNS-RIKEN joint project for large-scale nuclear structure calculations, Natural Sciences and Engineering Research Council (NSERC) of Canada, the Deutsche Forschungsgemeinschaft – Projektnummer 279384907 – SFB 1245, the PRISMA Cluster of Excellence, and the BMBF under Contracts No. 05P18RDFN1 and 05P19RDFN1. TRIUMF receives funding via a contribution through the National Research Council Canada. Com-putations were performed at the Jülich Supercomputing Center (JURECA)

A new 11Be( d , p )12Be transfer reaction experiment was carried out in inverse kinematics at 26.9A MeV, with special efforts devoted to the determination of the deuteron target thickness and of the required optical potentials from the present elastic scattering data. In addition a direct measurement of the cross section for the 0 2 + state was realized by applying an isomer-tagging technique. The s-wave spectroscopic factors of 0.20 − 0.04 + 0.03 and 0.41 − 0.11 + 0.11 were extracted for the 0 1 + and 0 2 + states, respectively, in 12Be. Using the ratio of these spectroscopic factors, together with the previously reported results for the p-wave components, the single-particle component intensities in the bound 0 + states of 12Be were deduced, allowing a direct comparison with the theoretical predictions. It is evidenced that the ground-state configuration of 12Be is dominated by the d-wave intruder, exhibiting a dramatic evolution of the intruding mechanism from 11Be to 12Be, with a persistence of the N = 8 magic number broken.

We present an investigation of the structure of 13Be obtained via a kinematically complete measurement of the (p,pn) reaction in inverse kinematics at 265 MeV/nucleon. The relative energy spectrum of 13Be is compared to Transfer-to-the-Continuum calculations which use as structure inputs the overlaps of the 14Be ground-state wave function, computed in a three-body model, with the unbound states of the 13Be residual nucleus. The key role of neutron p-wave orbital in the interpretation of the low-relative-energy part of the spectrum is discussed. Keywords: Quasi-free scattering, Borromean nuclei, Three-body model, Resonances

We have investigated the coupling effect between magnetic and electric orders of the commensurate antiferromagnetic compound Nb 2 Co 4 O 9 . In magnetically ordered state ( T N = 27.5 K), a significant magnetoelectric effect, in which the electric polarization generated below its antiferromagnetic temperature shows a field-dependent increase, has been observed. Accordingly, the field-induced dielectric peak increases with the increasing applied magnetic field as well. In this manuscript, driving mechanisms of the spin-correlated dielectric anomalies and electric polarization in this compound have been discussed.

We report on the first γ-ray spectroscopy of 51,53K produced via the 52,54Ca(p,2p) reactions at ∼250 MeV/nucleon. Unambiguous final-state angular-momentum assignments were achieved for beam intensities down to few particles per second by using a new technique based on reaction vertex tracking combined with a thick liquid-hydrogen target. Through γ-ray spectroscopy and exclusive parallel momentum distribution analysis, 3/2+ ground states and 1/2+ first excited states in 51,53K were established quantifying the natural ordering of the 1 d 3 / 2 and 2 s 1 / 2 proton-hole states that are restored at N = 32 and 34. State-of-the-art ab initio calculations and shell-model calculations with improved phenomenological effective interactions reproduce the present data and predict consistently the increase of the E(1/2 1 + ) - E(3/2 1 + ) energy differences towards N = 40.

Mountain garlic is an edible perennial herb widely distributed in Asian, European, and Siberian regions, referring to a class of Allium species. In South Korea, mountain garlic mainly consists of two Allium species, Allium ochotense Prokh. and A. microdictyon Prokh. Due to having spicy garlic odor and nutrition contents, mountain garlic is used as a vegetable and traditional medicine in South Korea, Japan, and China. However, the genetic relationship between A. ochotense and A. microdictyon belonging to the subgenus Anguinum is still unclear. To understand the genetic diversity and phylogenetic relationships of mountain garlic populations in South Korea, we collected 25 mountain garlic materials from 8 geographical areas and analyzed their genetic diversity and relationships based on sequence variations of the nuclear ribosomal DNA (nrDNA) internal transcribed spacer (ITS) region. The DNA alignment result showed that A. ochotense and A. microdictyon were clearly divided into two groups, sharing 11 respective, particular nucleotide variable sites. It suggested that the nrDNA ITS region could be used to discriminate among Allium intraspecies. This species identification method would be utilized to distinguish unclear mountain garlic materials. This work not only provides more sequence resources of mountain garlic, but also validates the efficiency of the molecular discrimination method based on the nrDNA ITS region sequence.

A new constitutive model, which is a modification from Gao's second constitutive model, has been introduced by using the finite deformation theory. The new model fulfils the condition that strain energy becomes zero under no deformation. For incompressible polymer rubber materials, when n=1 and a=0, the new constitutive relation may be simplified to the Mooney-Rivlin model; when n=1 and α=1, the new constitutive relation may be simplified to the Neo-Hookean model. The discussions of basic finite deformation examples illustrate how the new constitutive model reasonably describes the deformation properties of polymer rubber materials, and how the applied range of polymer rubber materials have been broadened by using the new constitutive model.

From an inelastic excitation and breakup experiment with a 12Be beam at 29 MeV/u, a large 4He+8He cluster decay width of 1.1(2) MeV is determined for a state at an excitation energy of 10.3 MeV and with a spin parity of 0+. By using the R-matrix analysis, a cluster spectroscopic factor of 0.53(10) is extracted from the cluster partial width, providing a strong support for the clustering structure in 12Be. A specially designed zero-degree telescope played an essential role in the present experiment and has been demonstrated to be a promising tool in future studies of the molecular-like resonances near the cluster separation threshold.

The elastic scattering and breakup reactions of the halo nucleus $^{11}\mathrm{Be}$ on deuterons at an incident energy of $26.9A$ MeV are reported for the first time. Special attention has been paid to the determination and subtraction of the proton contaminations in the deuterated polyethylene ${({\mathrm{CD}}_{2})}_{n}$ target (where ${\mathrm{D}}_{2}$ denotes $^{2}\mathrm{H}_{2}$). The cross sections for elastic scattering are analyzed with the systematic optical potentials of Daehnick et al. and DA1p, as well as with single-folding potentials, derived from the Jeukenne-Lejeune-Mahaux effective nucleon-nucleon interaction. An extended version of the continuum-discretized coupled-channels (XCDCC) formalism, including dynamic core excitation (DCX) effects, is applied to analyze the elastic scattering and breakup data. Comparisons of the full XCDCC calculation with that omitting DCX effects indicate that the core excitation plays a remarkable role in reproducing breakup reactions of $^{11}\mathrm{Be}+d$.

Hot pepper is usually attacked by various pathogens, which can cause large production loss. Molecular identification is the most commonly used method to discriminate the species of pathogens, plants, and even animals. Among the numerous DNA markers, the nuclear ribosomal DNA (nrDNA) internal transcribed spacer (ITS) region was one of the most widely used markers for pathogen species systematics. In this study, we collected 26 pepper materials from different geographical regions in South Korea, and checked and identified the pathogen species they carried based on the sequence analysis result of the nrDNA ITS region. According to the sequence analysis analogue with the existing sequence reports in the NCBI GenBank database, there were five anthracnose Colletotrichum species found in 26 materials in all, including C. acutatum, C. scovillei, C. gloeosporioides, C. nymphaeae, and C. simmondsii. Among them, C. scovillei, considered the C. acutatum species complex, combined with C. acutatum and C. gloeosporioides, were considered as the most common anthracnose pathogens in peppers, while C. nymphaeae and C. simmondsii were firstly reported to infect peppers in South Korea, although these two species had been found to infect other vegetables, fruits, and other plant species. The effective advanced detection of potential pathogens would help to direct disease prevention and treatment.

A Multi-Neutron Correlation Spectrometer (MuNCoS) composed of 80 detector modules was constructed at Peking University. A position resolution of less than 3 cm (FWHM) for a typical long scintillation module was obtained based on cosmic ray tests. A calibration method using an unstable nucleus beam of 11 Be, together with the fragment identification by using a zero degree telescope, has been successfully developed. Neutron detection efficiencies of 15(1)% and 17(2)% were achieved for neutron energy intervals of 30–40 MeV and 40–60 MeV, respectively, and at a signal charge threshold of 4 MeVee. The experimentally determined neutron detection efficiencies agree well with the simulation based on the GEANT4 code.

BMBO (Ba2Mg(B3O6)2 crystal) is an excellent birefringent crystal and a potential stimulated Raman scattering (SRS) crystal. In this paper, high temperature Raman spectroscopy was used to in-situ study the melt structure near a BMBO crystal–melt interface. [B3O6]3− groups were found in this region. The result reveals that both of BaO bonds and MgO bonds are the weak bonds in the BMBO crystal structure. During the melting process, the crystal structure broke into Ba2+ ions, Mg2+ ions and [B3O6]3− groups. Our experimental results confirmed that the well-developed faces of BMBO crystals are the (001), (101) and (012) faces. Based on attachment energy theory, the crystal growth habit was discussed. The (001) (101) and (012) crystal faces linked by the weak BaO bonds and MgO bonds have smaller attachment energies and slower growth rates, and thus present in the final morphology. The (012) crystal face has a multi-terrace structure, which suggests that BMBO crystal grows with a layer-by-layer mode.

Ba2Mg ( B3O6 )( 2 ) (BMBO) is a potential stimulated Raman scattering (SRS) crystal . In this work, a colorless transparent BMBO single crystal with a dimension of 32x23x7 mm(3) has been grown by the Kyropoulos method. A spontaneous Raman spectrum of the crystal was recorded at room temperature. Site group analysis and first-principles calculations were employed to interpret the Raman spectrum . The site group analysis results show that the total lattice modes are 10A(g)+11A(u)+10E(g)+11E(u), of which 10A(g)+10E(g) are Raman -active. The crystal Raman spectrum was computed in CASTEP (Cambridge Sequential Total Energy Package) using a hybrid method combining density functional perturbation theory with the finite displacement method. All of the Raman -active modes have been identified. The internal modes of the B3O6 ring in the crystal give rise to vibrations with Raman shifts above 220 cm(-1); the translations and the librations of the rings, as well as the translations of the Ba2+ cations, give rise to vibrations with Raman shifts below 220 cm(-1). The strongest peak at 645 cm(-1) in the experimental spectrum is assigned to the breathing mode of the B3O6 ring.

With the development of technology and application requirements, researchers pay attention to not only magnetic properties of Alnico alloy but also its thermal stability. Their magnetic properties keeps in closely touch with phase microstructure[1], also Liu focuses on the effect of orientation degree of precipitated phase on thermal stability[2]. This paper mainly studies the influence of phase structure to thermal stability of Alnico8 alloys by adjusting the contents of Co and Nb(Sample A:36wt%Co; Sample B:36wt%Co, 1.1wt%Nb; Sample C:35wt%Co, 1.1wt%Nb). The morphology is characterized by Transmission Electron Microscope, the magnetic properties are measured by the B-H apparatus with closed circuit.

Background: For the deeply bound one-nucleon removal at intermediate energies using a $^{9}\text{Be}$ or $^{12}\text{C}$ target, a strong reduction of cross section was observed relative to the prediction of eikonal theoretical model. The large disagreement has not been explained and the systematic trend is inconsistent with results from transfer reactions. The recently observed asymmetric parallel momentum distribution of the knockout residue indicates the significant dissipative core-target interaction in the knockout reaction with a composite target, implying new reaction mechanisms beyond the eikonal reaction descriptions.Purpose: To investigate the reaction mechanism for deeply bound nucleon removal at intermediate energies.Method: Neutron removal from $^{14}\text{O}$ using a $^{12}\text{C}$ target at 60 MeV/nucleon was performed. Nucleon knockout cross sections were measured. The unbound excited states of $^{13}\text{O}$ were reconstructed by using the invariant mass method with the residues and the associated decay protons measured in coincidence. The measured cross sections are compared with an intra-nuclear cascade (INC) prediction.Results: The measured cross section of ($^{14}\text{O}$, $^{11}\text{C}$) is 60(9) mb, which is 3.5 times larger than that of ($^{14}\text{O}$, $^{13}\text{O}$) channel. This $2pn$-removal cross section is consistent with INC prediction, which is 66 mb with the main contribution being non-direct reaction processes. On the other hand, the upper limit of the cross section for one-neutron removal from $^{14}\text{O}$ followed by proton evaporation is 4.6(20) mb, integrated up to 6 MeV above the proton separation energy of $^{13}\text{O}$. The calculated total cross section for such reaction processes by the INC model is 2.5 mb, which is within the measured upper limit.Conclusions: The data provide the first constraint on the role of core excitation and evaporation processes in deeply bound nucleon removal from asymmetric nuclei. The experiment results suggest that non-direct reaction processes, which are not considered in the eikonal model, play an important role in deeply bound nucleon removal from asymmetric nuclei at intermediate energies.

The elastic scattering and breakup of the halo nucleus $^{11}\mathrm{Be}$ on protons at an incident energy of $26.9A$ MeV have been measured. The $^{11}\mathrm{Be}+p$ elastic scattering cross sections at various energies, including the present one, are systematically analyzed with the Chapel Hill 89 (CH89) and Koning-Delaroche (KD) global optical model potentials (OMPs), and the corresponding normalization factors are obtained. An extended version of the continuum-discretized coupled-channels (XCDCC) formalism, including dynamic core excitation effects, is applied to analyze the elastic scattering and breakup data. It is found that the core excitation plays a moderate role in the elastic scattering and breakup reaction of the halo nucleus $^{11}\mathrm{Be}$, being consistent with previous results at higher energies.

An overall irradiation and calibration technique was introduced and applied to a test scintillation detector array. An integral conversion method was used to reduce the nonlinearity of the time difference spectrum, and to improve the position determination especially for positions close to the two ends of a long scintillation bar. An overall position resolution of about 3.0 cm (FWHM) was extracted from the residual analysis method and verified by a direct measurement. Energy calibration was also realized by selecting cosmic rays at different incident angles. The bulk light attenuation lengths for the four test bars were also determined. It is demonstrated that these methods are especially efficient for calibrating large and complex detector arrays.

A new 11 Be(p,d) transfer reaction experiment is performed in inverse kinematics with a radioactive 11 Be beam at 26.9A MeV. Three low-lying states, namely the 0 + ground state, the 2 + state at Ex = 3.37 MeV, and the multiplet at around 6 MeV in 10 Be, are populated by this one-neutron transfer reaction. These three states in 10 Be are clearly discriminated from the Q-value spectrum, which is rebuilt from energies and angles of the recoil deuterons in coincidence with 10 Be. A spectroscopic factor for each state is extracted by comparing the experimental differential cross sections to the theoretical calculation results using the finite range adiabatic distorted wave approximation method with different global nucleon-nucleus potentials. It is found that the newly extracted spectroscopic factors for the 0 + and 2 + states are consistent with the previous ones, but the factor for the multiplet is smaller than the value in the reference, and the possible reason is discussed.

A pure aluminum matrix composite reinforced by Al 18 B 4 O 33 whisker with Bi 2 O 3 coatings was fabricated by squeeze casting method. The damping behaviors of the coated composites are investigated. The introduction of Bi at the interface between whisker and matrix in the coated composite during squeeze casting process plays an important role in the improvement of damping capacity. The results of damping characterization indicate that the damping capacity of the coated composites strongly depends on the coating contents and vibration frequencies. The damping mechanisms of the coated composites have changed when the vibration frequency changed. The presence of a critical temperature in the damping-temperature curves of the coated composites has been found first when the vibration frequencies have changed. The critical temperature decreased with the increasing of coating contents. The dominant damping mechanisms are transferred from dislocation damping (below the critical temperature) into interfacial damping (beyond the critical temperature).

This paper summarises pre-conceptual solutions for all sub-units of a potential rotating target system for the CSNS project. In order to test the validity of this concept and to gain first experience with a rotating target, the CSNS project has decided to embark on the construction of a mock-up test stand. The purpose is to provide first demonstration of the viability of the above concept by using a full model of the target head components and shaft and a dummy target with the right diameter and weight; confirm that acceptance criteria can be reached; gain experience in running a rotating target; verify certain parameters obtained by calculations. By carrying out a development program, it should be possible to produce a sound basis for a decision as to whether or not CSNS wants to adopt a rotating target as the preferred solution.