Astrophysically Important 26Si States Studied with the 28Si(4He,6He)26Si Reaction

Y. K. Kwon,이춘식,J. Y. Moon,J. H. Lee,J. Y. Kim,M. K. Cheoun,S. Kubono,H. Yamaguchi,J. J. He,A. Saito,Y. Wakabayashi,H. Fujikawa,G. Amadio,N. Iwasa,K. Inafuku,L. H. Khiem,M. Tanaka,Y. Fuchi,A. A. Chen,S 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.2

The emission of a 1.809-MeV γ-ray from the first excited state of 26Mg, followed by β-decay of 26Al in its ground state (denoted as 26Alg.s.), has been identied by several gamma-ray telescopes. To resolve the controversy over the possible sources of the observational 1.809-MeV γ-rays, one needs accurate knowledge of the production rate of 26Alg.s.. The 25Al(p,γ)26Si reaction is one of the most important astrophysical reactions to be investigated, but its rate is uncertain due to the lack of level information on 26Si above the proton threshold (Qpγ = 5.518 MeV). Illiadis et al. suggested that the 25Al(p,γ)26Si reaction should be dominated by a 3+ unnatural parity state at Ex = 5970 keV. Recent studies proposed several states as candidates for the 3+ states. However, the spin-parity assignments for these states are still uncertain. In the present work, we measured the 28Si(4He,6He)26Si reaction at 120 MeV to confirm the unnatural parity states just above the proton threshold. The measurement was performed with the high-resolution particle analyzer at the Center for Nuclear Study, University of Tokyo. We observed a total of 22 excited states in 26Si. The 7018-keV level, which was only observed by Bardayan et al. with the 28Si(p; t)26Si reaction, was confirmed in our measurement. Among the candidates of unnatural parity states at Ex = 5678, 5916, and 5945 keV, the 5918-keV state was only observed within the error of the excitation energy. A new state at Ex = 6101 keV was also identified.

In-situ preparation of WO_3/TiO_2 composite film with increased photo quantum efficiency on titanium substrate

J. He,Q.Z. Cai,D. Zhu,Q. Luo,D.Q. Zhang,X.W. Li,X. Zhao,W. Sun 한국물리학회 2011 Current Applied Physics Vol.11 No.1

A WO_3/TiO_2 composite film was in-situ prepared in tungstate electrolyte and characterized by Electron microscopy, X-ray diffraction, UV―Vis spectrophotometer and Photoluminescence. The oxide film consists of mixture phases of anatase and rutile, showing porous structures and metallurgical bond with substrate. With the incorporation of WO_3 into TiO_2, the optical absorption edge of TiO_2 filmwas shifted to longer wavelength slightly and the separation between electrons and holes was promoted effectively. WO_3/TiO_2 composite film with increased photo quantum efficiency will be promising in the treatment of environmental pollutants.

Distinct Electronic Structure for the Extreme Magnetoresistance in YSb

He, Junfeng,Zhang, Chaofan,Ghimire, Nirmal J.,Liang, Tian,Jia, Chunjing,Jiang, Juan,Tang, Shujie,Chen, Sudi,He, Yu,Mo, S.-K.,Hwang, C. C.,Hashimoto, M.,Lu, D. H.,Moritz, B.,Devereaux, T. P.,Chen, Y. L American Physical Society 2016 Physical Review Letters Vol.117 No.26

Enhanced delivery of T cells to tumor after chemotherapy using membrane-anchored, apoptosis-targeted peptide

He, X.,Bonaparte, N.,Kim, S.,Acharya, B.,Lee, J.Y.,Chi, L.,Lee, H.J.,Paik, Y.K.,Moon, P.G.,Baek, M.C.,Lee, E.K.,Kim, J.H.,Kim, I.S.,Lee, B.H. Elsevier Science Publishers 2012 Journal of controlled release Vol.162 No.3

Chemotherapy-induced apoptosis of tumor cells enhances the antigen presentation and sensitizes tumor cells to T cell-mediated cytotoxicity. Here we harnessed the apoptosis of tumor cells as a homing signal for the delivery of T cells to tumor. Jurkat T cells were anchored with ApoPep-1, an apoptosis-targeted peptide ligand, using the biocompatible anchor for membrane (BAM), an oleyl acid derivative. The ApoPep-1-BAM conjugate was efficiently anchored to cell membrane, while little anchoring was obtained with ApoPep-1 alone. The retention period of the ApoPep-1-BAM conjugate on cell membrane was approximately 80 and 40min in the absence and presence of serum, respectively. ApoPep-1 was resistant to degradation in serum until 2h. The apoptosis-targeted T cells that were anchored with the ApoPep-1-BAM preferentially bound to apoptotic tumor cells over living cells. When intravenously injected into tumor-bearing mice, the number of apoptosis-targeted T cells and in vivo fluorescence signals by the homing of the cells to doxorubicin-treated tumor were higher than those of untargeted T cells. Accumulation of apoptosis-targeted T cells at other organs such as liver was not detected. These results suggest that the chemotherapy-induced apoptosis and subsequent enhancement of T cell delivery to tumor by the membrane anchoring of the apoptosis-targeted peptide could be a novel strategy for cancer immunotherapy.

R&D Status of High-current Accelerators at IFP

J. J. Deng,J. S. Shi,W. P. Xie,L. W. Zhang,K. Z. Zhang,S. P. Feng,J. Li,M. Wang,Y. He,L. S. Xia,Z. Y. Dai,H. T. Li,L. Wen,S. F. Chen,X. Li,Q. G. Lai,M. H. Xia,Y. C. Guan,S. Y. Song,L. Chen 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.61

High-current accelerators have many important applications in Z-pinches, high-power microwaves, and free electron lasers, imploding liners and radiography and so on. Research activities on Zpinches, imploding liners, radiography at the Institute of Fluid Physics (IFP) are introduced. Several main high-current accelerators developed and being developed at IFP are described, such as the Linear Induction Accelerator X-Ray Facility Upgrade (LIAXFU, 12 MeV, 2.5 kA, 90 ns), the Dragon-I linear induction accelerator (20 MeV, 2.5 kA, 60 ns), and the Primary Test Stand for Z-pinch (PTS, 10 MA, 120 ns). The design of Dragon-II linear induction accelerator (20 MeV, 2.5 kA, 3 × 60 ns) to be built will be presented briefly.

A bridge from monotectic alloys to liquid-phase-separated bulk metallic glasses: Design, microstructure and phase evolution

He, J.,Mattern, N.,Tan, J.,Zhao, J.Z.,Kaban, I.,Wang, Z.,Ratke, L.,Kim, D.H.,Kim, W.T.,Eckert, J. Elsevier Science 2013 ACTA MATERIALIA Vol.61 No.6

The Zr-Ce-La system is characterized by a miscibility gap and a monotectic reaction. It separates into Zr-rich and CeLa-rich liquids upon cooling through the gap. Based on this system, a new Zr-Ce-La-Al-Co monotectic system was created to synthesize liquid-phase-separated bulk metallic glasses (LPS-BMGs) by copper mold casting. A systematical investigation was performed for the effects of the relative atomic ratios of Zr:CeLa, Co:Al and Ce:La on the microstructure features and chemical compositions of the two coexistent phases. Dual atom pairs with positive heat of mixing (Zr-Ce: +12kJmol<SUP>-1</SUP> and Zr-La: +13kJmol<SUP>-1</SUP>) are originally adopted to develop such LPS-BMGs. A series of in situ formed LPS-BMGs with a critical thickness of 2.5mm has been successfully synthesized. By combining the kinetics of liquid-liquid phase separation with the formation of metallic glasses, the mechanisms of phase formation and the microstructure evolution in the rapidly cooled alloys are discussed in detail. Furthermore, a thermodynamic model is proposed for LPS-BMG design, attempting to build a bridge from monotectic/immiscible (M/I) alloys to LPS-BMGs. This work not only provides opportunities for new insights into the synthesis of LPS-BMGs and their properties but also opens new perspectives for processing and research of M/I alloys.

Synthesis of ultra-thin tellurium nanoflakes on textiles for high-performance flexible and wearable nanogenerators

He, W.,Van Ngoc, H.,Qian, Y.T.,Hwang, J.S.,Yan, Y.P.,Choi, H.,Kang, D.J. New York] ; North-Holland 2017 APPLIED SURFACE SCIENCE - Vol.392 No.-

We report that ultra-thin tellurium (Te) nanoflakes were successfully grown on a sample of a gold-coated textile, which then was used as an active piezoelectric material. An output voltage of 4V and a current of 300nA were obtained from the bending test under a driving frequency of 10Hz. To test the practical applications, Te nanoflake nanogenerator (TFNG) device was attached to the subject's arm, and mechanical energy was converted to electrical energy by means of periodic arm-bending motions. The optimized open-circuit voltage and short-circuit current density of approximately 125V and 17μA/cm<SUP>2</SUP>, respectively, were observed when a TFNG device underwent a compression test with a compressive force of 8N and driving frequency of 10Hz. This high-power generation enabled the instantaneous powering of 10 green light-emitting diodes that shone without any assistance from an external power source.

δ-catenin overexpression promotes angiogenic potential of CWR22Rv-1 prostate cancer cells via HIF-1α and VEGF

He, Y.,Kim, H.,Ryu, T.,Kang, Y.,Kim, J.A.,Kim, B.H.,Lee, J.H.,Kang, K.,Lu, Q.,Kim, K. North-Holland Pub ; Elsevier Science Ltd 2013 FEBS letters Vol.587 No.2

This study revealed that CWR22Rv-1 cells overexpressing δ-catenin display bigger tumor formation and higher angiogenic potentials than their matched control cells in the CAM assay. In addition, δ-catenin overexpression in CWR22Rv-1 cells results in increased hypoxia-inducible factor 1-alpha (HIF-1α and vascular endothelial growth factor (VEGF) expression. Furthermore, δ-catenin overexpression was found to enhance nuclear distribution of both β-catenin and HIF-1α in hypoxic condition, which is diminished by knockdown of δ-catenin. Our current study adds novel evidence regarding contribution of δ-catenin to the progression of prostate cancer.

Effect of carbon contents and Ti addition on microstructure of ultralow carbon steel

He, Y.S.,Dong, J.L.,Lee, C.Y.,Yoon, J.,Lee, B.,Shin, K. Maney Publishing 2012 Materials technology Vol.27 No.1

Temperature-Dependent Raman Study of the Pyrochlore Superconductor Cd2Re2O7

J.S. Bae,양인상,D. Madrus,Hyun Kyung Ko,J. He,R. Jin,T.W. Noh,Y.S. Lee 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.5I

We present the results of Raman studies of the pyrochlore superconductor Cd2Re2O7 as a function of temperature. The overall features of the observed Raman spectra are in accord with the prediction of the factor group analysis and clearly identify two successive structural transitions, one at 200 K and the other at 120 K. New modes at 156, 325, and 411 cm.1 appear below 200 K, and peaks at 193 . 200 cm.1 and at 345 cm.1 are detected below 120 K. Moreover, the peak near 676 cm.1 shows an abrupt softening by 20 cm.1 below 200 K, but a slow hardening behavior below 120 K. On the other hand, the slope of the full width at half maximum of the peak at 230 cm.1 is found to decrease abruptly below 200 K, which appears to be parallel with the changes in the electric properties. This is indicative of the close relation between the lattice dynamics and the electronic properties. Our Raman spectra suggest that the structural changes at 200 K and 120 K in the Re- O(1) network, where O(1) is for oxygen atom at the apex of the ReO6 octahedron, is responsible for the changes in the electronic properties of the Cd2Re2O7 compound.