The level structure of the double-magic nucleus 34 Si（Z=14,N=20） was investigated by evaluating the available data.On the basis of experimental results from the beta-decay and fusion-evaporation reactions,we established the level scheme by assigning spin-parities up to 6 1 + at 6233 keV.The high energy positions of the excited states are consistent with the magicity at 34 Si,such as the 2 2 + state of the spherical ground band at 4.519 MeV and the3 - ,4 - ,and 5 - states of the one-particle one-hole cross-shell states at approximately 4.5 MeV.This nucleus,for a long time,has attracted much attention because of,on one side,a proton bubble structure in the ground state and,on the other side,a deformation in the second 0 + state,0 2 + .By a comparison of the constructed level scheme with the shell model calculations,we describe the emerging structures in the ground and second 0 + states and the negative-parity 3 - states within the framework of the shell model context.We propose a deformed rotational band with the cascading 6 2 + -4 1 + -2 1 + transitions built on the 0 2 + state.

The excited states of the neutron-rich nucleus 140I were, for the first time, investigated by a β-delayed γ-ray spectroscopy. The parent nuclide 140Te was produced through the in-flight fission of the 238U beam at 345 MeV per nucleon on a 9Be target at the Radioactive Isotope Beam Factory (RIBF), RIKEN in Japan. The half-life of 140Te was measured to be 350(5) ms and the spin-parity of ground state of 140I was found to be 2−. The spin-parities of three levels at 926, 1188, and 1787 keV were assigned as 1+ based on log f t values. These allowed Gamow-Teller (G-T) transition-states could be interpreted as the transformation of a neutron in the h9/2 orbital into a proton in the h11/2 orbital. Systematic features of level structures and G-T transitions are discussed in the frameworks of the large-scale shell model and deformed shell model.

The search for new isotopes using the in-flight fission of a U-238 beam has been conducted concurrently with decay measurements, during the so-called EURICA campaigns, at the RIKEN Nishina Center RI Beam Factory. Fission fragments were analyzed and identified in flight using the BigRIPS separator. We have identified the following 36 new neutron-rich isotopes: Rb-104, Zr-113, Nb-116, Mo-118,Mo-119, Tc-121,Tc-122, Ru-125, Rh-127,Rh-128, Pd-129,Pd-130,Pd-131, Ag-132, Cd-134, In-136,In-137, Sn-139,Sn-140, Sb-141,Sb-142, Te-144,Te-145, I-146,I-147, Xe-149,Xe-150, Cs-149,Cs-150,Cs-151, Ba-153,Ba-154, and La-154,La-155,La-156,La-157.

A new isomer with ms half-life was observed in 160Nd at RIBF, RIKEN Nishina Center by using in-flight fission of 238U beam and a cluster-type Ge detector array, EURICA. The experimental results and a PSM calculation indicate that the isomer in 160Nd is a 2 quasi-particle excitation of neutrons with a configuration of n1/2[521]x7/2[633] as the case in other N = 100 isotones. The E(4+)/E(2+) ratio of the ground-state band, 3.29, shows the 160Nd is well deformed and the ground band has a rotational nature. The 4- excitation of 160Nd showed an increase in energy by ~100 keV compared to that of 162Sm as predicted by the PSM calculation. A PSM calculation was performed by changing input beta_4 value and confirmed that the large hexadecupole deformation in Nd was responsible for the increase of the isomer energy.

We offer a possibility that the nuclear system with protons, Z = 8 has a large deformation at neutrons, N = 20; 28O that is beyond the neutron drip line. According to our previous works [arXiv: 1604.05013, 1604.02786, 1604.01017], it is expected that the ferro-deformation would occur at Z = 8, N = 20 through a shape phase transition at N = 18 out of N =16. The shape transition can be explained in terms of isospin dependent spin-orbital interactions between neutrons in the d3/2 orbital and protons in the d5/2 orbital, by yielding both the neutron and the proton pseudo-shell configurations built on each combined subshells. We argue that such a large deformation at N = 18 would be responsible for the 26O to be unbound, leading to a ground state neutron emitter. The ferro-deformation is mapped on the nuclear chart such that is around the following critical proton, neutron coordinates, (Z, N); (64, 104), (40, 64), (20, 40), (8, 20). This configuration depicts a beautiful pattern coming from a harmonious order in the microscopic quantum world.

We exhibit a wide variety of the nuclear shape phases over the nuclear chart along with a shell model scheme. Various nuclear shapes are demonstrated within the framework of proton-neutron spin-orbital interactions; ferro-deformed, sub-ferro-deformed, and spherical shapes. The spherical shape is classified into the three magic-number categories in view of a large shell gap mechanism; double-magic nuclei I, double magic nuclei II, and double magic nuclei III. We discuss nuclear shape coexistence in the space Z = 76 to 84 as providing a new way to understanding the dynamical shape phases.

We study a global nuclear structure in the framework of experimental observables. With the aid of large nuclear structure data at the national nuclear data center, NNDC, we present the distinctive systematic patterns emerged in the first 2+ excited energies, E(2+) and their energy ratios to the first 4+ levels, R = E(4+)/E(2+), in the even-even nuclei, over 50 < Z < 82 for protons, and 50 < N < 126 for neutrons. We introduce the so-called pseudo-shell configurations from the subshells mixture in order to explain a semi-double shell closure, a shape phase transition, and a reinforced deformation. It is found that the reinforced deformation arises when Z = 64 or 66 correlates with N = 90 and reaches its maximum, indicating R = 3.3. Such a saturated reinforced deformation spans over Z = 58 to 72 and N = 100 to 106 as showing its center at Z = 64 or 66 and at N = 102 or 104. We define this reinforced deformation 'a ferro-deformation' like a ferro-magnetism in condensed matter physics. The shape coexistence would be expected to occur, such as a ferro-deformation, with a strong rotational mode, and a near spherical shape, with a vibrational mode, at the critical points of Z = 64 or 66, with N = 88 and 90; 150Sm and 152Sm, 152Gd and 154Gd, and 154Dy and 156Dy. We suggest that a super-deformation, which can be formed at high-lying excited states in a moderate deformed nucleus, would correspond to the ferro-deformation at N = 88 for the nuclei; Sm, Gd, and Dy. We argue that the ferro-deformation can be closely associated with a strong spin-orbital interaction between neutrons and protons in the spin-orbit doublet, h9/2-h11/2, leading to the critical points at Z, N = 64, 104.

We present nuclear physics programs based on the planned experiments using rare isotope beams (RIBs) for the future Korean Rare Isotope Beams Accelerator facility(KRIA). This ambitious facility has both an Isotope Separation On Line (ISOL) and fragmentation capability for producing RIBs and accelerating beams of wide range mass of nuclides with energies of a few to hundreds MeV per nucleon. Low energy RIBs at Elab = 5 to 20 MeV per nucleon are for the study of nuclear structure and nuclear astrophysics toward and beyond the drip lines while higher energy RIBs produced by inflight fragmentation with the reaccelerated ions from the ISOL enable to explore the neutron drip lines in intermediate mass regions. The planned programs have goals for investigating internal structures of the exotic nuclei toward and beyond the nucleon drip lines by addressing the following issues: how the shell structure evolves in areas of extreme proton to neutron imbalance; whether the isospin symmetry maintains in isobaric mirror nuclei at and beyond the drip lines; how two-proton radioactivity affects abundances of the elements; what the role of the continuum states including resonant states above protondecay threshold in exotic nuclei is in astrophysical nuclear reaction processes, and how the nuclear reaction rates triggered by unbound proton-rich nuclei make an effect on rapid proton capture processes in a very hot stellar plasma.

We suggest that the emergence of a large deformation in the magnesium, Mg, nuclides, especially at the Z = 12, N = 12, should be associated with an octahedral deformed shape. Within the framework of molecular geometrical symmetry, we find a possibility that the Z = 12, N = 12 system would form an octahedral structure consisting of six points of alpha(4He) particles, yielding the ground collectivity. With this point of view, we draw the following serial molecular structures; the Z = 10, N = 10, 20Ne, corresponds to a hexahedral, the Z = 8, N = 8, 16O, does to a tetrahedral, and the Z = 6, N = 6, 12C, does to a trigonal symmetry. Moreover, the Z = 2, N = 2, 4He(alpha), fits into a tetrahedral symmetry with four points of nucleons; two protons and two neutrons. The enhanced deformation at Z = 12 with N > 20 would be explained by a deformed shape related to an Ethene(Ethylene)-like skeleton with six alpha particles. The deformation at Z = 10, with N = 10 and 12, can be interpreted as being attributed to a hexahedral shape combined by five alpha particles as well. By noticing that the Z = 4, N = 4 system is unstable to the ground state under two-body system with two alpha particles, we conclude that alpha particles, rather than the eight-protons-neutrons nucleon, govern the 8Be stability. Accordingly, the alpha particle should be a third nucleon, like a proton or a neutron, in a nucleus. We name it the 'Alpharon'. With this picture, we are able to open a new gate toward understanding of nuclear many-body systems; nucleon-nucleon interaction, shell structures, nucleon-synthesis, and nuclear matters. We argue that nature favors three-body systems; three quarks for a nucleon, three nucleons for a nucleus.

With the experimental data at the national nuclear data center, NNDC, we investigate systematically the emerging nuclear structure properties in the first 2+ excited energies, E(2+) and their energy ratios to the first 4+ levels, R = E(4+)/E(2+) in the nuclei over 28 < Z < 50 for protons, and 40 < N < 70 for neutrons. By introducing the pseudo-shell configurations built on the combined subshells, we explain the following phenomena; a semi-double shell closure, a shape phase transition, and a reinforced deformation. The reinforced deformation arises suddenly at Z = 40 (or 38), N = 60 and approaches a maximum value, R = 3.3, as being centered at Z = 40, N = 64. We define this reinforced deformation 'a ferro-deformation', as in the previous study [arXiv:1604.01017]. The shape coexistence would be expected to be, as forming a ferro-deformation, with a strong rotational mode, and a near spherical shape, with a vibrational mode, in the transitional region at N = 58, 60, and 62 for the nuclei, with Z = 38 and 40; 96Sr, 98Sr, 100Sr, and 98Zr, 100Zr, and 102Zr. We suggest that the ferro-deformation should be closely associated with a strong spin-orbital interaction between neutrons in the g7/2 orbital and protons in the g9/2 orbital. Such an isospin dependent spin-orbital interaction, with the same angular momentum, l = 4, reinforces nuclear surface toward a sudden and dramatic deformation, giving rise to the ferro-deformation at the critical point, Z = 40, N = 64. We discuss the similarities and differences of the ferro-deformation between the two critical points; Z = 40, N = 64 and Z = 64, N = 104.

We present a possibility that the system with Z = 20, N = 40, 60Ca, has a large deformation, even though it has both proton and neutron magic numbers, symbolizing a spherical nucleus. This large deformation corresponds to the so-called ferro-deformation that occurs at the particular critical points over the nuclear chart. By comparisons with the ferra-deformation at the critical point Z = 40, N = 64 [arXiv:1604.02786], we draw a conclusion that shape phase transitions should occur at Z = 18 or 20 when N = 36 to 38, which leads to a ferro-deformation at the critical points of Z = 18 or 20, N = 40; 58Ar, 60Ca. We explain the shape phase transition in terms of isospin dependent spin-orbital interactions between neutrons in the f5/2 orbital and protons in the f7/2 orbital. We find a universal behavior over the nuclear chart for yielding the ferro-deformation such that; Z = 64, N = 104, Z = 40, N = 64, and Z = 20, N = 40, respectively. This feature is linked to concept of the neutron(n)-proton(p)interaction in spin-orbital couplings such that; nh9/2-ph11/2, ng7/2-pg9/2, and nf5/2-pf7/2, respectively. It is suggested that triple shape coexistence would be possible in the Z = 20, N = 36, 56Ca, and the Z = 18, N = 36, 54Ar, where the ferro-deformation is expected to be built on the second 0+ state. The predicted level schemes for 52Ar, 54Ar, 56Ar, 56Ca, 58Ca, and 60Ca are presented.

We propose an organic photovoltaic (OPV) device with the energy conversion layer. In this structure, the energy conversion layer is formed on the outer surface of the conventional P3HT:PCBM solar cells. Rubrene layer is used for the spectral down-conversion layer. Rubrene layer absorbs the ultraviolet light and re-emits visible light, wavelengths of which coincide with the optical absorption spectrum range of the photoactive layer of the solar cell. In this paper, the thickness effects of the energy conversion layer on the energy conversion efficiency of the OPV device were demonstrated. Considerable increase about 1.5 times in the efficiency was achieved.

R. Lozeva,1,* A. Odahara,2 C.-B. Moon,3 S. Nishimura,4 P. Doornenbal,4 H. Naı̈dja,1,5,6 F. Nowacki,1 P.-A. Söderström,4 T. Sumikama,7 G. Lorusso,4 J. Wu,8,4 Z. Y. Xu,9 H. Baba,4 F. Browne,10,4 R. Daido,2,4 J.-M. Daugas,11 F. Didierjean,1 Y. Fang,2,4 T. Isobe,4 I. Kojouharov,5 N. Kurz,5 Z. Patel,12,4 S. Rice,12,4 H. Sakurai,4,9 H. Schaffner,5 L. Sinclair,13,4 H. Watanabe,14 A. Yagi,2,4 R. Yokoyama,15 T. Kubo,4 N. Inabe,4 H. Suzuki,4 N. Fukuda,4 D. Kameda,4 H. Takeda,4 D. S. Ahn,4 D. Murai,16 F. L. Bello Garrote,17 E. Ideguchi,18 T. Ishigaki,2,4 H. S. Jung,19 T. Komatsubara,20 Y. K. Kwon,20 S. Morimoto,2,4 M. Niikura,9 H. Nishibata,2,4 I. Nishizuka,7,4 T. Shimoda,2 and K. Tshoo20 1IPHC, CNRS, IN2P3 and University of Strasbourg, F-67037 Strasbourg Cedex 2, France 2Department of Physics, Osaka University, Osaka 560-0043 Toyonaka, Japan 3Department of Display Engineering, Hoseo University, Chung-Nam 336-795, Republic of Korea 4RIKEN Nishina Center, Wako-shi, Saitama 351-0198, Japan 5GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt, Germany 6University of Constantine, 25000 Constantine, Algeria 7Department of Physics, Tohoku University, Miyagi 980-8578, Japan 8School of Physics and State key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China 9Department of Physics, University of Tokyo, Tokyo 113-0033, Japan 10School of Computing, Engineering and Mathematics, University of Brighton, Brighton BN2 4GJ, United Kingdom 11CEA, DAM, DIF, F-91297 Arpajon Cedex, France 12Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom 13Department of Physics, University of York, Heslington, York YO10 5DD, United Kingdom 14School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191, China 15CNS, University of Tokyo, Wako, Saitama 351-0198, Japan 16Department of Physics, Rikkyo University, Toshima, Tokyo 171-8501, Japan 17Department of Physics, University of Oslo, N-0316, Oslo, Norway 18RCNP, Osaka University, Ibaraki, Osaka 567-0047, Japan 19Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA 20Rare Isotope Science Project, Institute for Basic Science, Daejeon 305-811, Republic of Korea (Received 1 May 2015; revised manuscript received 3 July 2015; published 3 August 2015; corrected 5 August 2015)

The KOBRA (KOrea Broad acceptance Recoil spectrometer and Apparatus) is a multi-purpose recoil spectrometer for low-energy nuclear experiments at the RAON accelerator complex. It is divided into two stages based on the operational function: the first stage (F0–F3) is an in-flight separator or beam transport line, and the second stage (F3–F5) is a large acceptance spectrometer. For spectrometers using radioactive ion (RI) beams, high performance, such as high resolution and large acceptance, are especially required due to the limit of quality of RI beams. In this respect, a dispersion-matching technique and a movable magnet system were employed for high resolution and large acceptance, respectively. Reaction spectra at the focal plane for the dispersion matching mode were obtained and analyzed using a Monte Carlo simulation code. In addition, the geometrical angular acceptances with respect to the distance between the reaction target and the first Q-pole doublet of the second stage were calculated, and the expected maximum solid angle of the spectrometer was estimated.

Blue phosphorescent organic light-emitting diodes (PHOLEDs) were fabricated using double dopants FIrpic and FIr6 in emissive layer (EML) with structure of ITO/NPB (700Å)/mCP:FIrpic-8%:FIr6-x% (300Å)/TPBi (300Å)/Liq (20Å)/Al (1200Å). We optimized concentration of the second dopant FIr6 in the presence of a fixed FIrpic to observe its effect on electrical performance of PHOLED device. 24.8cd/A of luminous efficiency was achieved by the device with dopant ratio of 8%FIrpic:4%FIr6 in EML. Efficiency roll-off was also improved 20% compared to the PHOLED device singly dopped with FIrpic or FIr6 only. Second doping proved its effect in stabilizing charge balance in EML and enhancing energy transfer of triplet excitons between two dopants.

We investigated the optical properties of light emission based on the resonance energy transfer mechanism between two molecules in the host–dopant systems. For this purpose, we fabricated the organic light-emitting devices with the different doped emissive layers. The host matrices were made of 4,4′,4″-tris(carbasol-l-nyl)triphenylamine (TCTA) and 2-methyl-9,10-di(2-naphthyl)anthracene (MADN) molecules and the doped molecules were 5,6,11,12-tetraphenylnaphtacene (Rubrene) and 4-(Dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidin-4-yl-vinyl)-4H-pyran (DCJTB). The concentrations of the doped molecules were 0.1%, 0.3%, 0.5%, and 0.8%. Through spectroscopic analysis using multi-peak fits with a Gaussian function to the emission spectra, we obtained the relative light intensity of the two dopants according to the doping concentrations and examined the relations between the molecular excited energy states and the nature of energy transfer in the host and dopant systems. We show that the luminous efficiency of the devices has a strong correlation between the energy transfer owing to the individual molecular intrinsic properties and the electrical characteristics associated with the bulky properties in the devices.