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51.
Here we show a technique to obtain a tilt series of dark-field (DF) transmission electron microscopy (TEM) images in ordering alloys for tomographic three-dimensional (3D) observations. A tilt series of DF TEM images of D1a-ordered Ni4Mo precipitates in a Ni-Mo alloy was successfully obtained by adjusting a diffraction condition for a superlattice reflection from the Ni4Mo precipitates. Since the superlattice reflection usually has a long extinction distance, dynamic diffraction effects such as thickness fringes can be suppressed to some extent with precise realignment of the diffraction condition. By using the tilt series of the DF TEM images, we attempted a computed TEM tomography to visualize 3D shapes and positions of the precipitates. 相似文献
52.
D‐A1‐D‐A2 Backbone Strategy for Benzobisthiadiazole Based n‐Channel Organic Transistors: Clarifying the Selenium‐Substitution Effect on the Molecular Packing and Charge Transport Properties in Electron‐Deficient Polymers 下载免费PDF全文
Yang Wang Tsukasa Hasegawa Hidetoshi Matsumoto Takehiko Mori Tsuyoshi Michinobu 《Advanced functional materials》2017,27(33)
Unipolar n‐type semiconducting polymers based on the benzobisthiadiazole (BBT) unit and its heteroatom‐substituted derivatives are for the first time synthesized by the D‐A1‐D‐A2 polymer‐backbone design strategy. Selenium (Se) substitution is a very effective molecular design, but it has been seldom studied in n‐type polymers. In this study, within the similar conjugated framework, the Se substitution effects on the optical, electrochemical, solid‐state polymer packing, electron mobility, and air‐stability of the target unipolar n‐type polymers are unraveled. Replacing the sulfur (S) atom in the thiadiazole heterocycles with the Se atom leads to narrower bandgaps and deeper lowest unoccupied molecular orbital (LUMO) levels of the n‐type polymers. Furthermore, the Se‐substituted polymer (pSeN‐NDI) shows shorter lamellar packing distances and stronger edge‐on π–π stacking interactions than its S‐counterpart (pSN‐NDI), as observed by the two‐dimensional grazing‐incidence wide‐angle X‐ray scattering (GIWAXS) patterns. With the deeper LUMO level and thin‐film microstructures suitable for transistors, pSeN‐NDI exhibits four‐fold higher electron mobilities (μe) than pSN‐NDI. However, the other Se‐containing polymer, pSeS‐NDI, forms rather amorphous film structures, which is caused by its limited thermal stability and decomposition during the thermal annealing processes, thus giving rise to a lower μe than its S‐counterpart (pBBT‐NDI). Most importantly, pBBT‐NDI demonstrates an electron mobility of 0.039 cm2 V?1 s?1, which is noticeable among the unipolar n‐type polymers based on the BBT and its analogs. 相似文献
53.
Jingtao Xu Jiazhen Wu Satoshi Heguri Gang Mu Yoichi Tanabe Katsumi Tanigaki 《Journal of Electronic Materials》2012,41(6):1177-1180
Polycrystalline samples of type?I clathrate Ba8Ni x Ge46?x (x?=?3, 4, 6) have been synthesized using a radio-frequency (RF) induction furnace. Ba8Ni x Ge46?x samples show metallic-like behavior (d??/dT?>?0) with high resistivity at room temperature, and diamagnetic susceptibility at 2?K and 300?K. The charge carriers vary from n type to p type depending on the Ni stoichiometry. The carrier concentrations at 300?K are calculated to be 5.84(3)?e?/cell for x?=?3, 2.29(1)?e?/cell for x?=?4, and 3.29(1)?h+/cell for x?=?6. The deviation of the carrier concentrations from the values expected based on 4-bonded Ni suggests that vacancies may play a very important role in the electronic states. The effective carrier masses are estimated from the low-temperature heat capacity data. 相似文献
54.
Tetsuya Iizuka Hideki Sezutsu Ken‐ichiro Tatematsu Isao Kobayashi Naoyuki Yonemura Keiro Uchino Kenichi Nakajima Katsura Kojima Chiyuki Takabayashi Hiroaki Machii Katsushige Yamada Hiroyuki Kurihara Tetsuo Asakura Yasumoto Nakazawa Atsushi Miyawaki Satoshi Karasawa Hatsumi Kobayashi Junji Yamaguchi Nobuo Kuwabara Takashi Nakamura Kei Yoshii Toshiki Tamura 《Advanced functional materials》2013,23(42):5232-5239
Silk is a protein fiber used to weave fabrics and as a biomaterial in medical applications. Recently, genetically modified silks have been produced from transgenic silkworms. In the present study, transgenic silkworms for the mass production of three colors of fluorescent silks, (green, red, and orange) are generated using a vector originating from the fibroin H chain gene and a classical breeding method. The suitability of the recombinant silks for making fabrics is investigated by harvesting large amounts of the cocoons, obtained from rearing over 20 thousand silkworms. The application of low temperature and a weakly alkaline solution for cooking and reeling enables the production of silk fiber without loss of color. The maximum strain tolerated and Young's modulus of the fluorescent silks are similar to those of ordinary silk, although the maximum stress value of the recombinant silk is slightly lower than that of the control. Fabrics with fluorescent color are demonstrated using the recombinant silk, with the color persisting for over two years. The results indicate that large amounts of genetically modified silk can be made by transgenic silkworms, and the silk is applicable as functional silk fiber for making fabrics and for use in medical applications. 相似文献
55.
Jason H. C. Yang Kungen Teii Chung-Chueh Chang Seiichiro Matsumoto Miriam Rafailovich 《Advanced functional materials》2021,31(4):2005066
Cubic boron nitride (c-BN) has an ultrahardness and a large bandgap energy like diamond. In the last 30 years, most of the attention has been directed towards the mechanical and electronic applications of c-BN, while its biological potential has been overlooked. The authors report in vitro biocompatibility of high-quality c-BN films prepared by plasma-enhanced chemical vapor deposition using the chemistry of fluorine. c-BN films become superhydrophilic when chemical-treated in hydrogen and nitrogen plasmas with or without the impact of low-energy ions due to a marked increase in polar part of the surface free energy by removal of the fluorine atoms terminating c-BN surfaces. Satisfactory proliferation and differentiation of osteoblastic cells comparable with a control sample and a superhydrophilic nanocrystalline diamond film, and the formation of mineral deposits by biomineralization are confirmed on the superhydrophilic c-BN films with negative values of zeta potential. The results demonstrate a high potential of c-BN as a noncytotoxic ultrahard coating material for biological and biomedical applications. 相似文献
56.
Seiya Suzuki Takuya Iwasaki K. Kanishka H. De Silva Shigeru Suehara Kenji Watanabe Takashi Taniguchi Satoshi Moriyama Masamichi Yoshimura Takashi Aizawa Tomonobu Nakayama 《Advanced functional materials》2021,31(5):2007038
Germanene, a 2D honeycomb germanium crystal, is grown at graphene/Ag(111) and hexagonal boron nitride (h-BN)/Ag(111) interfaces by segregating germanium atoms. A simple annealing process in N2 or H2/Ar at ambient pressure leads to the formation of germanene, indicating that an ultrahigh-vacuum condition is not necessary. The grown germanene is stable in air and uniform over the entire area covered with a van der Waals (vdW) material. As an important finding, it is necessary to use a vdW material as a cap layer for the present germanene growth method since the use of an Al2O3 cap layer results in no germanene formation. The present study also proves that Raman spectroscopy in air is a powerful tool for characterizing germanene at the interfaces, which is concluded by multiple analyses including first-principles density functional theory calculations. The direct growth of h-BN-capped germanene on Ag(111), which is demonstrated in the present study, is considered to be a promising technique for the fabrication of future germanene-based electronic devices. 相似文献
57.
Kun Liang Ray A. Matsumoto Wei Zhao Naresh C. Osti Ivan Popov Bishnu P. Thapaliya Simon Fleischmann Sudhajit Misra Kaitlyn Prenger Madhusudan Tyagi Eugene Mamontov Veronica Augustyn Raymond R. Unocic Alexei P. Sokolov Sheng Dai Peter T. Cummings Michael Naguib 《Advanced functional materials》2021,31(33):2104007
MXenes exhibit excellent capacitance at high scan rates in sulfuric acid aqueous electrolytes, but the narrow potential window of aqueous electrolytes limits the energy density. Organic electrolytes and room-temperature ionic liquids (RTILs) can provide higher potential windows, leading to higher energy density. The large cation size of RTIL hinders its intercalation in-between the layers of MXene limiting the specific capacitance in comparison to aqueous electrolytes. In this work, different chain lengths alkylammonium (AA) cations are intercalated into Ti3C2Tx, producing variation of MXene interlayer spacings (d-spacing). AA-cation-intercalated Ti3C2Tx (AA-Ti3C2), exhibits higher specific capacitances, and cycling stabilities than pristine Ti3C2Tx in 1 m 1-ethly-3-methylimidazolium bis-(trifluoromethylsulfonyl)-imide (EMIMTFSI) in acetonitrile and neat EMIMTFSI RTIL electrolytes. Pre-intercalated MXene with an interlayer spacing of ≈2.2 nm, can deliver a large specific capacitance of 257 F g−1 (1428 mF cm−2 and 492 F cm−3) in neat EMIMTFSI electrolyte leading to high energy density. Quasi elastic neutron scattering and electrochemical impedance spectroscopy are used to study the dynamics of confined RTIL in pre-intercalated MXene. Molecular dynamics simulations suggest significant differences in the structures of RTIL ions and AA cations inside the Ti3C2Tx interlayer, providing insights into the differences in the observed electrochemical behavior. 相似文献
58.
Matsumoto S. Hiraoka Y. Ishiyama T. Sakai T. Yachi T. Yamada I. Ito A. Arimoto Y. 《Electron Devices, IEEE Transactions on》1998,45(9):1940-1945
The device characteristics of a quasi-SOI power MOSFET were investigated to obtain its optimum device structure. The oxide at the original bottom surface of the bulk power MOSFET of the quasi-SOI power MOSFET formed by reversed silicon wafer direct bonding acts as the buried oxide of the conventional SOI power MOSFET. The short channel effect of the quasi-SOI power MOSFET was larger than that in the conventional SOI power MOSFET. It was suppressed by increasing the width of the oxide in the body region, and the parasitic bipolar effect was suppressed by decreasing it. We also propose a new device structure which can suppress the short channel effect and parasitic bipolar effect of a quasi-SOI power MOSFET based on the results of these experiments 相似文献
59.
Characteristics of thermally expanded core fiber 总被引:1,自引:0,他引:1
Thermally expanded core (TEC) fiber is expected to reduce fiber-to-fiber and fiber-to-laser diode connection loss. This paper describes the characteristics of TEC fiber theoretically and experimentally. We reveal theoretically that when fabricating TEC fiber the mode field diameter (MFD) is enlarged more effectively by increasing the heating temperature rather than the heating time. In the 1300-1600°C temperature range with heating times between 0 and 60 min, it is necessary to control the temperature accurately so that no deviation from the target temperature is more than ±30°C. This is in order to ensure that any connection loss caused by MFD mismatch is less than 0.1 dB. We show experimentally that the propagation loss of TEC fiber is dependent on the heating region and wavelength by using a micro burner with a propane/oxygen flame. Based on the relationship between the loss characteristics and the expanded MFD, we suggest a method for nondestructively measuring the MFD in TEC fibers 相似文献
60.
A novel high-isolation structure for a polarisation-insensitive nonreciprocal device intended for optical circulator application is proposed. It consists of birefringent crystals and polarisation rotators. Experimental demonstration shows an isolation of over 42 dB and an insertion loss of under 1.5 dB.<> 相似文献