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Ren, Q.*; Gupta, M. K.*; Jin, M.*; Ding, J.*; Wu, J.*; Chen, Z.*; Lin, S.*; Fabelo, O.*; Rodriguez-Velamazan, J. A.*; Kofu, Maiko; et al.
Nature Materials, 22, p.999 - 1006, 2023/05
Yan, S. Q.*; Li, X. Y.*; Nishio, Katsuhisa; Lugaro, M.*; Li, Z. H.*; Makii, Hiroyuki; Pignatari, M.*; Wang, Y. B.*; Orlandi, R.; Hirose, Kentaro; et al.
Astrophysical Journal, 919(2), p.84_1 - 84_7, 2021/10
Times Cited Count:1 Percentile:9.31(Astronomy & Astrophysics)Chen, Y. Q.*; Tanida, Kiyoshi; Belle Collaboration*; 181 of others*
Physical Review D, 102(1), p.012002_1 - 012002_12, 2020/07
Times Cited Count:9 Percentile:62.97(Astronomy & Astrophysics)Ono, Akira*; Xu, J.*; Colonna, M.*; Danielewicz, P.*; Ko, C. M.*; Tsang, M. B.*; Wang, Y,-J.*; Wolter, H.*; Zhang, Y.-X.*; Chen, L.-W.*; et al.
Physical Review C, 100(4), p.044617_1 - 044617_35, 2019/10
Times Cited Count:52 Percentile:98.56(Physics, Nuclear)International comparison of heavy-ion induced reaction models were discussed in the international conference "Transport2017" held in April 2017. Owing to their importance for safety assessment of heavy-ion accelerators and dosimetry of astronauts, various models to simulate heavy-ion induced reaction models are developed. This study is intended to clarify the difference among them to pinpoint their problems. In the comparison study, 320 protons and neutrons were packed in a 20-fm-large cube to calculate the number and energies of collisions during the time evolution. The author contributed to this study by running calculation using JQMD (JAERI Quantum Molecular Dynamics). This study showed that time step in the calculation is one of the biggest causes of the discrepancies. For example, the calculation by JQMD comprises 1-fm/c time steps, each of which is composed of transport, scattering and decay phases. Therefore a sequence of scattering, and decay followed by another scattering in 1 fm/c cannot be considered. Moreover, in JQMD particles are labeled by sequential numbers and scattering reactions are simulated by the order. Therefore scattering between low ID numbers, that between high ID numbers and that between the first (low ID) pair is overlooked in JQMD. Above indications obtained in this study must be kept in our mind for future JQMD upgrades.
Li, B.; Wang, H.*; Kawakita, Yukinobu; Zhang, Q.*; Feygenson, M.*; Yu, H. L.*; Wu, D.*; Ohara, Koji*; Kikuchi, Tatsuya*; Shibata, Kaoru; et al.
Nature Materials, 17(3), p.226 - 230, 2018/03
Times Cited Count:110 Percentile:96.86(Chemistry, Physical)Zhang, Y.-X.*; Wang, Y,-J.*; Colonna, M.*; Danielewicz, P.*; Ono, Akira*; Tsang, M. B.*; Wolter, H.*; Xu, J.*; Chen, L.-W.*; Cozma, D.*; et al.
Physical Review C, 97(3), p.034625_1 - 034625_20, 2018/03
Times Cited Count:90 Percentile:99.11(Physics, Nuclear)International comparison of heavy-ion induced reaction models were discussed in the international conference "Transport2017" held in April 2017. Owing to their importance for safety assessment of heavy-ion accelerators and dosimetry of astronauts, various models to simulate heavy-ion induced reaction models are developed. This study is intended to clarify the difference among them to pinpoint their problems. In the comparison study, 320 protons and 320 neutrons were packed in a 20-fm-large cube to calculate the number of particle-particle collisions as well as the energies of collisions during the time evolution. In addition to the calculation, their algorithms were compared. The author contributed to this study by running calculation using JQMD (JAERI Quantum Molecular Dynamics). The results were compared with those calculated by the other 15 codes from over the world. Algorithm comparison showed that JQMD calculates collision probabilities from protons at first and collisions by neutrons are simulated later, which might be unreasonable. On the other hand, it was clarified that the calculation by JQMD agrees with those by the others. Despite the fact that some codes deviate from the average by a factor of 2, JQMD exhibited stable performance.
Yan, S. Q.*; Li, Z. H.*; Wang, Y. B.*; Nishio, Katsuhisa; Lugaro, M.*; Karakas, A. I.*; Makii, Hiroyuki; Mohr, P.*; Su, J.*; Li, Y. J.*; et al.
Astrophysical Journal, 848(2), p.98_1 - 98_8, 2017/10
Times Cited Count:5 Percentile:21.72(Astronomy & Astrophysics)Yan, S. Q.*; Li, Z. H.*; Wang, Y. B.*; Nishio, Katsuhisa; Makii, Hiroyuki; Su, J.*; Li, Y. J.*; Nishinaka, Ichiro; Hirose, Kentaro; Han, Y. L.*; et al.
Physical Review C, 94(1), p.015804_1 - 015804_5, 2016/07
Times Cited Count:6 Percentile:44.68(Physics, Nuclear)Long, Y.-W.*; Kawakami, Takateru*; Chen, W.-T.*; Saito, Takashi*; Watanuki, Tetsu; Nakakura, Yuta*; Liu, Q.-Q.*; Jin, C.-Q.*; Shimakawa, Yuichi*
Chemistry of Materials, 24(11), p.2235 - 2239, 2012/06
Times Cited Count:35 Percentile:70.92(Chemistry, Physical)An A-site ordered perovskite-structure oxide, LaCuFeO, shows unusual intermetallic charge transfer between the A-site Cu and the B-site Fe ions. Like temperature, pressure also induces the intermetallic charge transfer at room temperature and the compound changes from low-pressure LaCuFeO to high-pressure LaCuFeO accompanying with significant volume collapse and as well as unusual softening in bulk modulus. In addition, the material was changed from an antiferromagnetic insulator to a paramagnetic metal transition. Either by physical or chemical (cation substitution) pressure, the charge-transfer transition temperature decreases, and the lower volume phase stabilizes Cu and Fe at the A and B sites, respectively.
Deng, Z.*; Jin, C. Q.*; Liu, Q. Q.*; Wang, X. C.*; Zhu, J. L.*; Feng, S. M.*; Chen, L. C.*; Yu, R. C.*; Arguello, C.*; Goko, Tatsuo*; et al.
Nature Communications (Internet), 2, p.1425_1 - 1425_5, 2011/08
Times Cited Count:150 Percentile:93.71(Multidisciplinary Sciences)In a prototypical ferromagnet (Ga,Mn)As based on a III-V semiconductor, substitution of divalent Mn atoms into trivalent Ga sites leads to severely limited chemical solubility and metastable specimens available only as thin films. The doping of hole carriers via (Ga,Mn) substitution also prohibits electron doping. To overcome these difficulties, Masek et al. theoretically proposed systems based on a I-II-V semiconductor LiZnAs, where isovalent (Zn,Mn) substitution is decoupled from carrier doping with excess/deficient Li concentrations. Here we show successful synthesis of Li(ZnMn)As in bulk materials. We reported that ferromagnetism with a critical temperature of up to 50 K is observed in nominally Li-excess compounds, which have p-type carriers.
Chen, L.-M.; Kando, Masaki; Xu, M. H.*; Li, Y.-T.*; Koga, J. K.; Chen, M.*; Xu, H.*; Yuan, X.-H.*; Dong, Q. L.*; Sheng, Z. M.*; et al.
Physical Review Letters, 100(4), p.045004_1 - 045004_4, 2008/02
Times Cited Count:90 Percentile:92.62(Physics, Multidisciplinary)We observed the increase of the K- X-ray conversion efficiency (hK) produced by a 60 fs frequency doubled high contrast laser pulse focused on Cu foil, compared to the case of the fundamental laser pulse. hK shows a strong dependence on the nonlinearly skewed shape of the laser pulse. It reaches a maximum for a 100 fs negatively skewed pulse. The electron spectrum shaping contributes to the enhancement of hK. Simulations demonstrate that high contrast lasers are an effective tool for optimizing the X-ray emission, via the enhanced Vacuum Heating mechanism.
Yamasaki, Chisato*; Murakami, Katsuhiko*; Fujii, Yasuyuki*; Sato, Yoshiharu*; Harada, Erimi*; Takeda, Junichi*; Taniya, Takayuki*; Sakate, Ryuichi*; Kikugawa, Shingo*; Shimada, Makoto*; et al.
Nucleic Acids Research, 36(Database), p.D793 - D799, 2008/01
Times Cited Count:51 Percentile:71.37(Biochemistry & Molecular Biology)Here we report the new features and improvements in our latest release of the H-Invitational Database, a comprehensive annotation resource for human genes and transcripts. H-InvDB, originally developed as an integrated database of the human transcriptome based on extensive annotation of large sets of fulllength cDNA (FLcDNA) clones, now provides annotation for 120 558 human mRNAs extracted from the International Nucleotide Sequence Databases (INSD), in addition to 54 978 human FLcDNAs, in the latest release H-InvDB. We mapped those human transcripts onto the human genome sequences (NCBI build 36.1) and determined 34 699 human gene clusters, which could define 34 057 protein-coding and 642 non-protein-coding loci; 858 transcribed loci overlapped with predicted pseudogenes.
Chen, L.-M.; Kotaki, Hideyuki; Nakajima, Kazuhisa*; Koga, J. K.; Bulanov, S. V.; Tajima, Toshiki; Gu, Y. Q.*; Peng, H. S.*; Wang, X. X.*; Wen, T. S.*; et al.
Physics of Plasmas, 14(4), p.040703_1 - 040703_4, 2007/04
Times Cited Count:36 Percentile:75.67(Physics, Fluids & Plasmas)An experiment for the laser self-guiding studies has been carried out with 100 TW laser pulse interaction with the long underdense plasma. Formation of extremely long plasma channel with its length, about 10 mm, 20 times above the Rayleigh length is observed. The self-focusing channel features such as the laser pulse significant bending and the electron cavity formation are demonstrated experimentally for the first time.
Xu, M. H.*; Chen, L.-M.; Li, Y.-T.*; Yuan, X.-H.*; Liu, Y.-Q.*; Nakajima, Kazuhisa; Tajima, Toshiki; Wang, Z.-H.*; Wei, Z.-Y.*; Zhao, W.*; et al.
Acta Physica Sinica, 56(1), p.353 - 358, 2007/01
Times Cited Count:5 Percentile:37.33(Physics, Multidisciplinary)The characteristics of X-ray sources generated by p-polarized femtosecond laser-solid interactions are experimentally studied in the relativistic regime. By use of knife-edge image technique and a single-photon-counting X-ray CCD camera, we obtain the source size, the spectrum and the conversion efficiency of the X-ray sources. The experimental results show that the conversion efficiency of photons reaches an optimum value 7.0810/sr at the laser intensity of 1.610W/cm, which is different from the Reich's simulation results. We find that about 10% of laser energy is converted into the forward hot electrons at the laser intensity of 1.610W/cm.
Chen, Z. Q.; Yamamoto, Shunya; Kawasuso, Atsuo; Xu, Y. H.; Sekiguchi, Takashi*
Applied Surface Science, 244(1-4), p.377 - 380, 2005/05
Times Cited Count:16 Percentile:55.81(Chemistry, Physical)Homo- and heteroepitaxial ZnO films were grown by pulsed laser deposition on single crystal ZnO substrate and AlO substrate, respectively. The surface roughness probed by atomic force microscope (AFM) depends strongly on the substrate, which is much larger for the heteroepitaxial layer. Doppler broadening of positron annihilation measurements show existence of defects in both of the films, with a higher concentration in the homoepitaxial film. Raman scattering measurements reveal the E2 phonon vibration mode at 437 cm, which is characteristic of the wurtzite structure. These films show strong ultraviolet (UV) emission at 3.3 eV from the cathodoluminescence measurements, which indicates good optical properties.
Chen, Z. Q.; Kawasuso, Atsuo; Xu, Y.; Naramoto, Hiroshi*; Yuan, X. L.*; Sekiguchi, Takashi*; Suzuki, Ryoichi*; Odaira, Toshiyuki*
Physical Review B, 71(11), p.115213_1 - 115213_8, 2005/03
Times Cited Count:104 Percentile:93.73(Materials Science, Multidisciplinary)ZnO crystals were implanted with 20-80 keV hydrogen ions up to a total dose of 4.410 cm. Positron annihilation measurements show introduction of zinc vacancies, which are filled with hydrogen atoms. After isochronal annealing at 200-500 C, the vacancies agglomerate into hydrogen bubbles. Further annealing at 600-700 C causes release of hydrogen out of the bubbles, leaving large amount of microvoids. These microvoids are annealed out at high temperature of 1000 C. Cathodoluminescence measurements reveal that hydrogen ions also passivate deep level emission centers before their release from the sample, and lead to the improvement of the UV emission.
Chen, Z. Q.; Kawasuso, Atsuo; Xu, Y.; Naramoto, Hiroshi; Yuan, X. L.*; Sekiguchi, Takashi*; Suzuki, Ryoichi*; Odaira, Toshiyuki*
Journal of Applied Physics, 97(1), p.013528_1 - 013528_6, 2005/01
Times Cited Count:147 Percentile:96.39(Physics, Applied)Phosphorus ions were implanted into ZnO crystals with energies of 50-380 keV to a dose of 10-10 cm. Positron annihilation measurements show the introduction of vacancy clusters after implantation. These vacancy clusters evolve to microvoids after annealing at a temperature of 600C, and disappear gradually up to 1100C. Raman scattering measurements show the production of oxygen vacancies (V). They are annealed up to 700C accompanying the agglomeration of vacancy clusters. The light emissions of ZnO are suppressed due to the competing nonradiative recombination centers introduced by implantation. Recovery of the light emission occurs above 600C. The vacancy-type defects detected by positrons might be part of the nonradiative recombination centers. Hall measurement shows n-type conductivity for the P-implanted ZnO layer, which suggests that phosphorus is an amphoteric dopant.
Chen, L.-M.; Koga, J. K.; Kando, Masaki; Kotaki, Hideyuki; Nakajima, Kazuhisa; Bulanov, S. V.; Tajima, Toshiki; Xu, M. H.*; Li, Y.-T.*; Dong, Q. L.*; et al.
no journal, ,
Interaction of intense Ti: Sapphire laser with Cu foil targets has been studied by measuring hard X-ray generation. Hard X-ray spectroscopy and K X-ray conversion efficiency () from Cu plasma have been studied as a function of laser intensity via pulse duration scan (60 fs 600 fs), laser pulse energy scan (60 mJ 600 mJ) and target displacement scan from best focus. For intensity I W/cm, the Cu keep on increasing to reach a maximum value of at an intensity W/cm. The focusing is varied widely to give a range of intensities from 10 W/cm W/cm. Comparing to a recent publication, two individual emission peaks are obtained, one is at best focal spot and the other is at larger target offset corresponding to W/cm. Each peak is corresponding to different energy absorption mechanism. In addition, when we introduce slightly detuning of compressor gratings at the best focal condition, it shows generated by negatively skewed 100 fs pulse width laser irradiation reach and almost 7 times greater than the case of positively skewed pulse. Vacuum Heating is greatly stimulated in this case and preciously control of pre-plasma is the key factor in tuning control of X-ray emission in relativistic fs regime.
Koga, J. K.; Chen, L.-M.; Kotaki, Hideyuki; Nakajima, Kazuhisa; Bulanov, S. V.; Tajima, Toshiki; Gu, Y. Q.*; Peng, H. S.*; Hua, J. F.*; An, W. M.*; et al.
no journal, ,
First experiments for electron acceleration with the laser-gas plasma interaction have been carried out with 30 fs, 100 TW relativistic Ti:Sapphier laser pulse into a long slit (1.2 10 mm) gas plasma. The 10 mm length plasma channel formed that was longer than 20 times the Rayleigh length. Plasma density was the key factor for this long channel stimulation under 100 TW laser pulse irradiation that was much higher than critical power for relativistic self-focusing. For the first time, channel characteristics such as laser bending, hosing and cavity formation were demonstrated experimentally. In case of long channel guiding, accelerated electron bunch was tightly collimated with low emmitance mm mrad and quasi-monoenergetic electron bunch ( 70 MeV) was obtained as well. Accelerated electron charge current with electron energy 1 MeV was 10 nC/shot which was highest value in laser accelerator, to our knowledge, and ascribed to the contribution of long plasma channel. These well controlled laser-driven acceleration is an important cornerstone of relativistic engineering.
Kameshima, Takashi; Kotaki, Hideyuki; Kando, Masaki; Daito, Izuru; Kawase, Keigo; Fukuda, Yuji; Chen, L. M.*; Homma, Takayuki; Kondo, Shuji; Esirkepov, T. Z.; et al.
no journal, ,
The acceleration method of laser plasma electron acceleration has very strong electric field, however, the acceleration length is veryshort. Hence, the energy gain of electron beams were confined to be approximately 100 MeV. Recently, this problem was solved by using discharge capillary. The feature of plasma was used that high dense plasma has low refractive index. Distributing plasma inside capillary as low dense plasma is in the center of capillary and high dense plasma is in the external side of capillary can make a laser pulse propaget inside capillary with initial focal spot size. Experiments with capillary were performed in China Academy of Engineering Physics (CAEP) and Japan Atomic Energy Agency (JAEA). We obtained the results of 4.4 J laser pulse optical guiding in 4 cm capillary and 0.56 GeV electron production in CAEP in 2006, and 1 J laser pulse optical guiding in 4 cm capillary and electron beams productions.