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991.
Fan Zhang Akio Yoshinaka Robert C. Ripley 《Propellants, Explosives, Pyrotechnics》2024,49(3):e202300260
A structural reactive material (SRM) cylinder is considered here as a limiting case of a dense metallic energetic system in which a mixture of metal particles is consolidated to the theoretical maximum density excluding porosity, to possess both high energy density and mechanical strength. Dynamic fragmentation and free-field explosion of a 103 mm inner diameter SRM cylinder charge is experimentally studied, with a wall thickness varying in a range of metal-to-explosive mass ratio M/C=1.3 to 4.0. Under explosive loading, the SRM cylinder produces a designated fragment size distribution divided into two groups: fine fragments with sizes on the order of 102 μm and below, and coarse fragments with sizes on the order ranging between 100-101 mm. Prompt detonation shock-induced reaction (DSIR) of the expanding cloud of high-concentration fine fragments supplements the energy to enhance the primary blast as it propagates, while the coarse fragments form a high-speed, high-concentration metal momentum flux crossing the fireball and blast front to contribute to the total impulse loading to a nearby structure. Rapid impact-induced reaction (IIR) of the secondary fragments from high-speed coarse SRM fragments further enhances the reflected blast loading or generates a high interior explosion pressure as fragments perforate into the structure. The above distinctive characteristics of a unique hetero-blast are coupled effectively in the near-field range. 相似文献
992.
Bun-Ichiro Ono Kazuyasu Kijima Nobuya Ishii Takahiro Kawato Akio Matsuda Andrzej Paszewski Sumio Shinoda 《Yeast (Chichester, England)》1996,12(11):1153-1162
We examined how the activity of O-acetylserine and O-acetylhomoserine sulphydrylase (OAS/OAH) SHLase of Saccharomyces cerevisiae is affected by sulphur source added to the growth medium and genetic background of the strain. In a wild-type strain, the activity was repressed if methionine, cysteine or glutathione was added to the growth medium. However, in a strain deficient of cystathionine γ-lyase, cysteine and glutathione were repressive, but methionine was not. In strains deficient of serine O-acetyltransferase (SATase), OAS/OAH SHLase activity was low regardless of sulphur source and was further lowered by cysteine and glutathione, but not by methionine. From these observations, we concluded that S-adenosylmethionine should be excluded from being the effector for regulation of OAS/OAH SHLase. Instead, we suspected that S. cerevisiae would have the same regulatory system as Escherichia coli for sulphate assimilation; i.e. cysteine inhibits SATase to lower the cellular concentration of OAS which is required for induction of the sulphate assimilation enzymes including OAS/OAH SHLase. Subsequently, we obtained data supporting this speculation. 相似文献
993.
Hiroyuki Nishimura Akio Nakashiba Ryuichiro Kawakami Fumio Inoue Toshio Inoue Shinzaburo Oshimo 《Polymer Composites》1993,14(6):473-480
This paper describes methods of evaluating polybutene electrofusion joints and results of mechanical strength measurements for an electrofusion joint. Suitable fusion conditions were determined qualitatively through measurement of fusion interface temperatures and observation of the fusion zone. A method of determining standard fusion conditions, based on the relation between heating time and tensile strength, is also indicated. Differences in thermal properties between polybutene and polyethylene resins are discussed. It was found that polybutene required less supplied power per unit fusion area for suitable fusion. It was also confirmed that an electrofusion joint required a cold zone. 相似文献
994.
Gisele G. Santos Oscar Peitl Akio Koike Shusaku Akiba Shigeki Sawamura Mikio Nagano Yoshitaka Saijo Susumu Harako Satoshi Yoshida Edgar D. Zanotto 《Journal of the American Ceramic Society》2023,106(1):596-612
A few authors have reasonably proposed that liquid–liquid phase-separated (LLPS) glasses could show improved fracture strength, Sf, and toughness, KIc, as the second phase could provide a barrier to crack propagation via deflection, bowing, trapping, or bridging. Due to the associated tensile or compressive residual stresses, the second phase could also act as a toughening or a weakening mechanism. In this work, we investigated five glasses of the PbO–B2O3–Al2O3 system spanning across the miscibility gap: Four of them undergo LLPS—three are binodal (two B2O3-rich and one PbO-rich) and one is spinodal—and one does not show LLPS (composition outside the miscibility gap). Their compositions were designed in such a way that the amorphous particles are under compressive residual stresses in some and under tensile residual stresses in others. The following mechanical properties were determined: the Vickers hardness, ball on three balls (B3B) strength, and toughness, KIc-SEVNB (single-edge V-notch beam [SEVNB]). The microstructures and compositions were analyzed using scanning electron microscopy with energy-dispersive X-ray spectrometry. The spinodal glass showed, by far, the best mechanical properties. Its KIc-SEVNB = 1.6 ± 0.1 MPa m1/2, which embodies an increase of almost 50% over the B2O3-rich binodal composition, and 90% considering the PbO-rich binodal composition. Moreover, its fracture strength, Sf = 166 ± 7 MPa, is one of the highest ones ever reported for an LLPS glass. Fracture analyses evidenced that the spinodal composition exhibited the lowest net stress at the fracture point. Moreover, calculations indicate that the internal residual stress level is the lowest in the spinodal glass. The overall results indicate that the microstructural effect of the spinodal glass is the most significant factor for its superior mechanical properties. This work corroborates the idea that LLPS provides a feasible and stimulating solution to improve the mechanical properties of glasses. 相似文献
995.
Artificial Life and Robotics - With the spread of COVID-19, the need for remote detection of physical conditions is increasing, for example, there are several situations wherein the body... 相似文献
996.
Oikawa Ryo Doi Akio Ishida Masaru Chakraborty Basabi 《Artificial Life and Robotics》2023,28(2):460-470
Artificial Life and Robotics - Percutaneous coronary intervention (PCI) is mainly used in the treatment of stenosis of the coronary arteries of the heart characteristic of coronary artery disease,... 相似文献
997.
998.
Artificial Life and Robotics - An operator feels a burden when he/she controls a rescue robot remotely because he/she has to keep watching camera images to find the target object. We think that... 相似文献
999.
Oilseed rape straw (OS), rice straw (RS), wheat straw (WS), and corn stover (CS) particles were used to reinforce bio-polyols based polyurethane (PU) foams. The influence of crop straws (XS) fillers on the stability in water, degradability in soil, thermal stability, and elasticity of foams were investigated. The incorporation of OS and CS particles in the PU matrix increased the stability of reinforced foams in water, while the addition of WS and RS particles made foams lower stability in water. PU foams reinforced by XS particles displayed mass reductions up to 53.8% after burying in soil for 250 days. The reinforced foams were more stable under heating but the enhancement of thermal stability trended to disappear after water immersion or soil burying. The reinforced foams showed better elasticity that incorporations of OS and CS made PU foams higher height recovery percentage, while RS and WS made the recovery percentage decline firstly and then enhance during three times compressions. All these four XS particles are suitable to modify bio-based PU foams, especially OS and CS particles appear to be more outstanding in preparing foams with higher stability in water, degradability in soil, thermal stability, and elasticity than RS and WS particles. 相似文献
1000.
Katsuki Hayashi Kazuki Mitsui Tatsuki Shimizu Rikiya Kado Takumi Umada Akio Koike Satoshi Yoshida Seiji Inaba Akira Saitoh 《Journal of the American Ceramic Society》2023,106(3):1732-1738
The well-known Makishima–Mackenzie relationship, consisting of two terms of the dense packing structure and dissociation energy regarding bonding in constituent oxides, enables fabricating oxide glasses with ultrahigh Young's modulus (∼140 GPa) and a small coefficient of thermal expansion (CTE) (∼4 ppm/K). The effects of increasing MgO and Ta2O5 contents in an MgO–Ta2O5–Al2O3–SiO2–B2O3 glass system using a conventional melt-quenching method are revealed. The essential oxides of Al2O3 and Ta2O5 are primarily suitable for dense packing structures dominated by a large coordination number of oxygens. The substitution of CaO by MgO results in high dissociation energy when the glass composition falls in the peraluminous regime (Al2O3/[MgO + CaO] > 1). A small CTE is realized by increasing the molar ratio of Al2O3/MgO. According to magic-angle spinning-nuclear magnetic resonance spectra, mechanically and thermally functional oxide glasses depend on their structures. These findings facilitate the development of glass substrate applications without thermal dilatation. 相似文献