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431.
Takashi Nakanishi Hirokazu Takahashi Tsuyoshi Michinobu Jonathan P. Hill Katsuhiko Ariga 《Thin solid films》2008,516(9):2401-2406
Fine-tuning of the supramolecularly organized nanometer scale architectures of fullerene derivatives, fulleropyrrolidines substituted with a mono-, di-, or tri(n-hexadecyloxy)phenyl group is described. These synthetic fullerene derivatives possess one- (1), two- (2), or three- (3) long alkyl chains. The correlation between the number of alkyl chain multiplicity and the self-organized bilayer structures as the fundamental subunit as well as the superstructures formed in different solvents were investigated using microscopic and spectroscopic techniques. The fullerene derivatives studied formed interdigitated lamellar bilayer structures whose d spacing values, estimated by X-ray diffraction patterns, are 2.63 nm for 1, 3.50 nm for 2, and 4.28 nm for 3, respectively. There are the two differing intermolecular forces present due to C60 (sp2-carbons) or alkyl chains (sp3-carbons). Fullerene moieties always exhibit strong π-π interactions, while van der Waals interactions between alkyl chains can be altered by variation of their multiplicity. Substitution of three alkyl chains at the fullerene moiety (3) was the most effective method for stimulating polymorphism in its derivatives in different solvents. 相似文献
432.
Sato Hirokazu Adachi Nozomu Todaka Yoshikazu Omura Tomohiko Sato Koichi 《Metallurgical and Materials Transactions A》2021,52(11):4749-4752
Metallurgical and Materials Transactions A - We revealed that hydrogen (H) in pure Fe promotes grain refinement during plastic deformation, which is caused by the increase in dislocation density by... 相似文献
433.
Akiko Isa Jun Minamino Haruna Mizuno Shigehiko Suzuki Yoichi Kojima Hirokazu Ito 《木材化学与工艺学杂志》2013,33(3):208-216
Abstract To improve the water resistance of bamboo flour/high-density polyethylene (HDPE) composites, the effects of plastic content, coupling agents, and the addition of micro-fibrillated cellulose (MFC) on formulations were studied, and their rheological and mechanical properties were evaluated. The composites were prepared by injecting molding with a basic composition of equivalent amounts of bamboo flour and HDPE, and the melting fluidity of the compounds, tensile strength, and tensile modulus of the composites were determined. An increase in water resistance was detected in all three tests. By increasing the plastic content, negative effects such as a decreased tensile modulus were observed. When evaluating the compatibility between bamboo flour and plastic using coupling agents and MFC addition, positive effects were noted for water resistance, melting fluidity, and tensile modulus. We also confirmed that the procedure used to increase the compatibility between bamboo flour and plastic could easily be used for industrial applications by changing the coupling agents. Overall, a novel positive property (increased tensile modulus) and an increased water resistance were observed after MFC addition. 相似文献
434.
Hirokazu Ishitobi Keirei Uruma Masato Takeuchi Junichi Ryu Yukitaka Kato 《Applied Thermal Engineering》2013,50(2):1639-1644
Lithium chloride (LiCl) modified magnesium hydroxide (Mg(OH)2) is a potential new material for chemical heat pumps. However, there is insufficient information concerning its dehydration and hydration behavior. In this study, the dehydration and hydration reactions, corresponding to the heat storage and the heat output operations, respectively, of authentic Mg(OH)2 and LiCl-modified Mg(OH)2 were investigated by thermogravimetric methods and near infrared spectroscopy. The dehydration of authentic Mg(OH)2 proceeded as a one-step reaction. In contrast, the dehydration of LiCl-modified Mg(OH)2 occurred in two steps. The dehydration reaction rates were increased by LiCl modification of the Mg(OH)2 surface, while the activation energy for the first-order dehydration reaction was lowered. The mechanism for the hydration reaction of magnesium oxide (MgO) was different to that for the hydration of LiCl-modified MgO. This difference was explained by the effect of the LiCl on the MgO particle surface. 相似文献
435.
A study on the life distribution and reliability for a roller guide with cage was carried out with a total number of 90 test samples in two lots (N s = 38 and 52), and different fatigue life distribution functions, such as the two and three parameter Weibull distributions, and the log-normal distribution were used for analyzing the test data. The basic dynamic load rating formula standardized by ISO in 2004 was also compared with the life test data in relation to the effect of crowning on both ends of the carriage raceway. This study revealed the following: (1) the best fit for the life test data was achieved by the three-parameter Weibull distribution with the third parameter being the minimum life γ, using a Weibull slope of m = 27/20, and a load life exponent of 10/3. The log-normal distribution came second, and the two-parameter Weibull distribution third. (2) The test data did not fit with the two-parameter Weibull distribution using a Weibull slope of 9/8, which had been used in the ISO linear bearing standard. (3) Fatigue failure on the roller guide was initiated near the starting points of the crowning on both ends of the carriage raceway. Almost 70% of the test specimens were found to have uneven and inclined contact situations with the rollers. (4) The basic dynamic load ratings evaluated theoretically fit well to the life test results, while the λ b m factors were also observed to fall within a suitable value range. 相似文献
436.
Hirokazu Kikuchi Sho Nakahara Takaaki Tomai Kazuo Terashima 《The Journal of Supercritical Fluids》2010,55(1):325-332
A two-dimensional, sheet-like dielectric barrier discharge microplasma that can be generated in supercritical fluids was developed. With this type of plasma, generated in supercritical xenon, nanocrystalline diamonds and diamondoid-like sp3 bonded nano-hydrocarbons were synthesized by using adamantane as a precursor and seed. Pressure and temperature were set close to the critical point of xenon at 6.3 MPa and 290.2 K, respectively. The peak-to-peak voltage for microplasma generation was between 3.4 and 7.1 kV, at a frequency of 10 kHz and the power consumption of the microplasma determined from the I-V measurements reached about 30 mW. Transmission electron microscopy analysis of the lattice of the synthesized particles revealed crystal structures similar to those observed in nanodiamonds, while micro-Raman spectra yielded features also found in Raman and ab initio computational studies of diamondoids. 相似文献
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For improving the ozone consumption efficiency (OCE) of the ozone-electrolysis process, an ozone-electrolysis system with an independent electrolytic cell from an ozone contactor (indirect ozone injection system) and a three-dimensional electrode were introduced in this study. The reactor successfully enhanced the OCE and the ratio of 1,4-dioxane degradation rate to ozone injection rate (RDO) in comparison with the previous reactor. The three-dimensional electrode also contributed the improvement of the OCE and the RDO due to lowering the current density on the cathode. As the indirect ozone injection system allows higher degree of freedom for the reactor design, it is useful for application of ozone-electrolysis to practical water treatments. 相似文献