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Journal Articles

Suppressed lattice disorder for large emission enhancement and structural robustness in hybrid lead iodide perovskite discovered by high-pressure isotope effect

Kong, L.*; Gong, J.*; Hu, Q.*; Capitani, F.*; Celeste, A.*; Hattori, Takanori; Sano, Asami; Li, N.*; Yang, W.*; Liu, G.*; et al.

Advanced Functional Materials, 31(9), p.2009131_1 - 2009131_12, 2021/02

 Times Cited Count:1 Percentile:24.67(Chemistry, Multidisciplinary)

The soft nature of organic-inorganic halide perovskites renders their lattice particularly tunable to external stimuli such as pressure, undoubtedly offering an effective way to modify their structure for extraordinary optoelectronic properties. However, these soft materials meanwhile feature a general characteristic that even a very mild pressure will lead to detrimental lattice distortion and weaken the critical light-matter interaction, thereby triggering the performance degradation. Here, using the methylammonium lead iodide as a representative exploratory platform, we observed the pressure-driven lattice disorder can be significantly suppressed via hydrogen isotope effect, which is crucial for better optical and mechanical properties previously unattainable.

Journal Articles

Development on laser cutting technique to suppress spatter particles aiming at disposal of radio-active waste

Naoe, Takashi; Teshigawara, Makoto; Futakawa, Masatoshi; Mizutani, Haruki; Muramatsu, Toshiharu; Yamada, Tomonori; Ushitsuka, Yuji*; Tanaka, Nobuatsu*; Yamasaki, Kazuhiko*

Proceedings of 8th International Congress on Laser Advanced Materials Processing (LAMP 2019) (Internet), 5 Pages, 2019/05

Laser cutting is one of the options in the disposal of radio-active waste, such as spallation neutron target vessel in J-PARC, etc. Due to unique characteristic of laser, such as non-contact system, it is more easily to provide remote-controlled system in comparison with conventional one, such as mechanical cutting machine, etc. However, a demerit of laser cutting is the sputter and fume caused by laser cutting, resulting in contamination with radio-active materials its surroundings. Recently it was developed that the spatter suppression technique by controlling laser beam profile in laser welding process. In order to apply this suppression technique to laser cutting, first of all, we attempted to observe the phenomenon at melting area during laser cutting using a high-speed video camera in order to make the physical model. The result showed that the appearance of fume and sputter were independently confirmed in the time evolution.

Journal Articles

Retreat from stress; Rattling in a planar coordination

Suekuni, Koichiro*; Lee, C. H.*; Tanaka, Hiromi*; Nishibori, Eiji*; Nakamura, Atsushi*; Kasai, Hidetaka*; Mori, Hitoshi*; Usui, Hidetomo*; Ochi, Masayuki*; Hasegawa, Takumi*; et al.

Advanced Materials, 30(13), p.1706230_1 - 1706230_6, 2018/03

 Times Cited Count:35 Percentile:90.91(Chemistry, Multidisciplinary)

Thermoelectric materials for highly efficient devices must satisfy conflicting requirements of high electrical conductivity and low thermal conductivity. In this paper, we studied the crystal structure and phonon dynamics of tetrahedrites (Cu,Zn)$$_{12}$$(Sb,As)$$_{4}$$S$$_{13}$$. The results revealed that the Cu atoms in a planar coordination are rattling, which effectively scatter phonons. These findings provide a new strategy for the development of highly efficient thermoelectric materials with planar coordination.

Journal Articles

Investigation of microstructure in additive manufactured Inconel 625 by spatially resolved neutron transmission spectroscopy

Tremsin, A. S.*; Gao, Y.*; Dial, L. C.*; Grazzi, F.*; Shinohara, Takenao

Science and Technology of Advanced Materials, 17(1), p.324 - 336, 2016/07

 Times Cited Count:17 Percentile:61.27(Materials Science, Multidisciplinary)

Journal Articles

The Study on application of laser technology for the reactor core dismantling

Iwai, Hiroki; Nakamura, Yasuyuki; Mizui, Hiroyuki; Sano, Kazuya; Morishita, Yoshitsugu

Proceedings of 7th International Congress on Laser Advanced Materials Processing (LAMP 2015) (Internet), 4 Pages, 2015/08

The reactor of FUGEN is characterized by its tube-cluster construction that contains 224 channels arranging both the pressure and the calandria tubes coaxially in each channel. And the periphery part of the core has the laminated structure of up to 150 mm thickness of carbon steel for radiation shielding. Method for dismantling the reactor core is also being studied with considering processes of dismantlement by remote-handling devices under the water for the radiation shielding. In order to shorten the term of the reactor dismantlement work and reduce the secondary waste, some cutting tests and literature research for various cutting methods had been carried out. As the result, the laser cutting method, which has feature of the narrow cutting kerf and the fast cutting velocity, was mainly selected for dismantling the reactor. In this presentation, current activities of FUGEN decommissioning and R&D of laser cutting tests are introduced.

Journal Articles

Surface modification effects on hydrogen absorption property of a hydrogen storage alloy by short pulse laser irradiation

Abe, Hiroshi; Shimomura, Takuya; Tokuhira, Shinnosuke*; Shimada, Yukihiro*; Takenaka, Yusuke*; Furuyama, Yuta*; Nishimura, Akihiko; Uchida, Hirohisa*; Daido, Hiroyuki; Oshima, Takeshi

Proceedings of 7th International Congress on Laser Advanced Materials Processing (LAMP 2015) (Internet), 4 Pages, 2015/08

A short pulse laser (the nanosecond and femtosecond) was applied to hydrogen absorbing alloys surface layer, and a surface modification experiment was put into effective to aim at improvement of hydrogen adsorption functionally. It was investigated about correlation between an initial hydrogen absorption reaction rate of hydrogen alloys and a laser irradiation in this research. The laser irradiation condition was done with pulse width 100 fsec and energy 0.2 - 3.4 mJ/pulse. It blazed down on hydrogen absorbing alloys (LaNi$$_{4.6}$$Al$$_{0.4}$$) and changed local order in the surface. As a result, the initial hydrogen absorption reaction rate was 1.5 - 3.0 times as fast as a irradiated sample, and the result and laser irradiated sample found out that a hydrogen absorption function improves. A laser irradiation can conclude to be effective in surface modification of the hydrogen storage materials.

Journal Articles

Novel electrothermodynamic power generation

Kim, Y.*; Kim, J.*; Yamanaka, Satoru*; Nakajima, Akira*; Ogawa, Takashi*; Serizawa, Takeshi*; Tanaka, Hirohisa*; Baba, Masaaki*; Fukuda, Tatsuo; Yoshii, Kenji; et al.

Advanced Energy Materials, 5(13), p.1401942_1 - 1401942_6, 2015/07

 Times Cited Count:8 Percentile:41.84(Chemistry, Physical)

An innovative electro-thermodynamic cycle based on temporal temperature variations using pyroelectric effect has been presented. Practical energy is successfully generated in both $textit{in-situ}$ synchrotron X-ray diffraction measurements under controlled conditions and $textit{Operando}$ real engine dynamometer experiments. The main generating origin is revealed as a combination of a crystal structure change and dipole change phenomenon corresponds to the temperature variation. In particular, the electric field induced 180$$^circ$$ domain switching extremely improves generating power, and the true energy breakeven with temperature variation is firstly achieved.

Journal Articles

X-ray line profile study on shot/laser-peened stainless steel

Kumagai, Masayoshi*; Akita, Koichi; Imafuku, Muneyuki*; Oya, Shinichi*

Advanced Materials Research, 996, p.39 - 44, 2014/08

 Times Cited Count:4 Percentile:92.01

The microstructural features of shot and laser peened austenitic stainless steels were studied using line profile analysis with X-rays. Although both specimens had similar residual stress profiles toward the depth direction, the microstructural features were different not only on the original surfaces of the specimens but also to several micrometers in depth. The dislocation densities of the SP specimen were greater than that of the LP specimen. And the crystallite sizes of the SP specimen were smaller than that of the LP specimen.

Journal Articles

Evaluation of welding residual stresses using diffraction spot trace method

Suzuki, Kenji*; Shobu, Takahisa; Shiro, Ayumi; Zhang, S.*

Advanced Materials Research, 996, p.76 - 81, 2014/08

 Times Cited Count:0 Percentile:0

Journal Articles

Very high cycle fatigue in pulsed high power spallation neutron source

Xiong, Z.*; Futakawa, Masatoshi; Naoe, Takashi; Maekawa, Katsuhiro*

Advanced Materials Research, 891-892, p.536 - 541, 2014/03

 Times Cited Count:6 Percentile:95.65

Very high cycle fatigue degradation of type 316L austenitic stainless steel, which is used as the structural material of neutron spallation sources under intensive neutron irradiation environment, is investigated by using an ultrasonic fatigue testing machine. The strain rate imposed on the structure of neutron spallation source is almost equivalent to that produced in the testing machine. The temperature on the surface was controlled by the air-cooling. The effect of strain rate on the fatigue strength is recognized to increase the fatigue limit.

Journal Articles

Cation and anion exchange membranes prepared by radiation-induced graft polymerization for application in electrodialysis

Chen, J.; Asano, Masaharu; Maekawa, Yasunari

Advanced Materials Research, 881-883, p.1157 - 1160, 2014/01

 Times Cited Count:1 Percentile:60.31

Cation and anion exchange membranes were prepared by radiation-induced graft polymerization of ethyl styrenesulfonate and chloromethyl styrene, respectively, onto poly(ethylene-$$alt$$-tetrafluoroethylene) (ETFE) films, followed by hydrolysis in the former case and quaternization in the latter case. The degree of grafting as well as the ion exchange capacity (IEC) and the conductivity of the prepared membranes were investigated. Furthermore, the cation and anion exchange membranes were tested in an electrodialysis cell using caesium ion aqueous solution in the dilute compartment. It was found that the high-IEC membranes enhanced the electrodialysis speed, while the low-IEC membranes showed the high percent removal.

Journal Articles

Transformation strain and texture evolution during diffusional phase transformation of low alloy steels studied by neutron diffraction

Xu, P. G.; Tomota, Yo*; Vogel, S. C.*; Suzuki, Tetsuya*; Yonemura, Masao*; Kamiyama, Takashi*

Reviews on Advanced Materials Science, 33(5), p.389 - 395, 2013/08

Journal Articles

Synthesis of a Ni-containing porous SiOC material from polyphenylmethylsiloxane by a direct foaming technique

Idesaki, Akira; Colombo, P.*

Advanced Engineering Materials, 14(12), p.1116 - 1122, 2012/12

 Times Cited Count:9 Percentile:33.5(Materials Science, Multidisciplinary)

Journal Articles

Phase-change materials; Vibrational softening upon crystallization and its impact on thermal properties

Matsunaga, Toshiyuki*; Yamada, Noboru*; Kojima, Rie*; Shamoto, Shinichi; Sato, Masugu*; Tanida, Hajime*; Uruga, Tomoya*; Kohara, Shinji*; Takata, Masaki*; Zalden, P.*; et al.

Advanced Functional Materials, 21(12), p.2232 - 2239, 2011/06

 Times Cited Count:103 Percentile:95.79(Chemistry, Multidisciplinary)

Thermal properties of the amorphous and crystalline state of phase-change materials show remarkable differences such as higher thermal displacements and a more pronounced anharmonic behavior in the crystalline phase. These findings are related to the change of bonding upon crystallization.

Journal Articles

Reverse Monte Carlo simulation approach on the amorphous structure of C$$_{59}$$N

Ferdows, M.; Suzuya, Kentaro; Kawakita, Yukinobu; Kohara, Shinji*; Kodama, Katsuaki; Yamamoto, Kazunori; Shamoto, Shinichi; Hirata, Takamichi*; Omote, Kenji*; Kasama, Yasuhiko*; et al.

Abstracts of 7th International Symposium on Advanced Materials in Asia-Pacific (NT 2010)/JAIST International Symposium on Nano Technology 2010 (7th ISAMAP), p.25 - 28, 2010/09

We performed Reverse Monte Carlo analysis (RMCA) to study amorphous structure of a heterofullerene, C$$_{59}$$N by using pulsed neutron powder diffraction data. The scattering function S(Q) shows that the structure is amorphous, while the atomic pair distribution function (PDF) shows that the local structure is similar to that of C$$_{60}$$. Obtained structures strongly depend on the initial models. Problems for this RMCA method are discussed.

Journal Articles

Hydrogenation and dehydrogenation of passivated aluminum under high pressure

Saito, Hiroyuki; Machida, Akihiko; Sakurai, Yoko; Katayama, Yoshinori; Aoki, Katsutoshi

Proceedings of 18th International Symposium on Processing and Fabrication of Advanced Materials (PFAM-18), p.75 - 80, 2009/12

Journal Articles

First-principles study on the decohesion of grain boundary by hydrogen trapping in Aluminum and other metals

Yamaguchi, Masatake; Ebihara, Kenichi; Itakura, Mitsuhiro; Kadoyoshi, Tomoko*; Suzudo, Tomoaki; Kaburaki, Hideo

Proceedings of 18th International Symposium on Processing and Fabrication of Advanced Materials (PFAM-18), p.65 - 74, 2009/12

Generally speaking, the reduction of surface energy by hydrogen trapping is not considered as a key factor in the mechanism of hydrogen embrittlement of metals. This is because it is not known how much hydrogen atoms can be trapped at grain boundaries of metals and how much the cohesive energy (work of fracture) of the grain boundary can be reduced by the hydrogen trapping. From first-principles, we calculated the cohesive energy of bcc Fe $$Sigma$$3(111) and fcc Al(Cu) $$Sigma$$5(012) symmetrical tilt grain boundaries with varying the trapping density of hydrogen. We found that the cohesive energy of Fe, Al and Cu grain boundaries can be significantly reduced by the hydrogen trapping; it indicates that the reduction of surface energy can cause the hydrogen embrittlement in all Fe, Al, and Cu grain boundaries.

Journal Articles

Bioleaching of enargite by arsenic-tolerant $$Acidithiobacillus$$ $$ferrooxidans$$

Sasaki, Keiko*; Takatsugi, Koichiro*; Hirajima, Tsuyoshi*; Kozai, Naofumi; Onuki, Toshihiko; Tuovinen, O. H.*

Advanced Materials Research, 71-73, p.485 - 488, 2009/05

 Times Cited Count:4 Percentile:91.13

no abstracts in English

Journal Articles

Synthesis of SiC based fibers with continuous pore structure by melt-spinning and controlled curing method

Kita, Kenichiro; Narisawa, Masaki*; Mabuchi, Hiroshi*; Ito, Masayoshi*; Sugimoto, Masaki; Yoshikawa, Masahito

Advanced Materials Research, 66, p.5 - 8, 2009/04

 Times Cited Count:2 Percentile:68.51

Journal Articles

Surface modification and deuterium retention in tungsten and molybdenum exposed to low-energy, high flux deuterium plasmas

Alimov, V.; Shu, Wataru; Roth, J.*; Komarov, D. A.*; Lindig, S.*; Isobe, Kanetsugu; Nakamura, Hirofumi; Yamanishi, Toshihiko

Advanced Materials Research, 59, p.42 - 45, 2009/00

 Times Cited Count:0 Percentile:0.12

63 (Records 1-20 displayed on this page)