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Kenji Hirota Kazuhiko Kitamura Yoshihiko Ukai Keiichi Matsunaga 《Journal of Materials Processing Technology》2014,214(10):2095-2101
In this paper, a new assembling method of spline joints that enables tight fitting in a simple manner by allowing slight plastic deformation at the spline teeth was introduced. Experiments were carried out for the spline joints of medium carbon steel varying the overlap zone between the male and the female spline teeth. Axial joining strength was increased with increase in the overlap length due to the residual compressive stress by forming. The joint by the proposed method also showed higher torsional strength than the conventional joint. Improvement in the torsional strength was explained based on the deformation and hardness distribution around the spline teeth. With respect to the shape of overlap zone, better results were obtained when using the specimen having a uniform overlap length along the axial direction. 相似文献
23.
Samuel L. Manzello Seul-Hyun Park Sayaka SuzukiJohn R. Shields Yoshihiko Hayashi 《Fire Safety Journal》2011,46(8):568-578
Attempting to experimentally quantify the vulnerabilities of structures to ignition from firebrand showers has remained elusive. The coupling of two facilities has begun to unravel this difficult problem. The NIST Firebrand Generator (NIST Dragon) is an experimental device that can generate a firebrand shower in a safe and repeatable fashion. Since wind plays a critical role in the spread of WUI fires in the USA and urban fires in Japan, NIST has established collaboration with the Building Research Institute (BRI) in Japan. BRI maintains one of the only full scale wind tunnel facilities in the world designed specifically for fire experimentation; the Fire Research Wind Tunnel Facility (FRWTF). The present investigation is aimed at extensively quantifying firebrand penetration through building vents using full scale tests. A structure was placed inside the FRWTF and firebrand showers were directed at the structure using the NIST Dragon. The structure was fitted with a generic building vent, consisting of only a frame fitted with a metal mesh. Six different mesh sizes openings were used for testing. Behind the mesh, four different materials were placed to ascertain whether the firebrands that were able to penetrate the building mesh assembly could ignite these materials. Reduced scale test methods afford the capability to test new vent technologies and may serve as the basis for new standard testing methodologies. As a result, a new experimental facility developed at NIST is presented and is known as the NIST Dragon's LAIR (Lofting and Ignition Research). The NIST Dragon's LAIR has been developed to simulate a wind driven firebrand attack at reduced scale. The facility consists of a reduced scale Firebrand Generator (Baby Dragon) coupled to a bench scale wind tunnel. Finally, a series of full scale experiments were conducted to visualize the flow of firebrands around obstacles placed downstream of the NIST Dragon. Firebrands were observed to accumulate in front of these obstacles at a stagnation plane, as was observed when the structure was used for firebrand penetration through building vent experiments, due to flow recirculation. The accumulation of firebrands at a stagnation plane presents a severe threat to ignitable materials placed near structures. 相似文献
24.
The mere exposure effect refers to the phenomenon where previous exposures to stimuli increase participants’ subsequent affective preference for those stimuli. This study explored the effect of selective attention on the mere exposure effect. The experiments manipulated the to-be-attended drawings in the exposure period (either red or green polygons in Experiments 1 and 2; both red and green polygons in Experiments 3 and 4) and black to-be-evaluated drawings in the affective judgment period (morphologically identical to the red or green polygons in Experiments 1 and 4; morphologically identical to the composite drawings in Experiments 2 and 3). The results showed a significant mere exposure effect only for the target shapes involved in attentional selection, even when the participants could recognize the nontarget shapes. This indicates that selective attention modulated the mere exposure effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
25.
Koshi Takenaka Miku Sato Masaya Mitamura Yasunori Yokoyama Naoyuki Katayama Yoshihiko Okamoto 《Journal of the American Ceramic Society》2020,103(4):2757-2763
We used spray-dry method to synthesize fine powder of β-Cu1.8Zn0.2V2O7 showing large negative thermal expansion (NTE) linearly to temperature over a wide temperature range. The NTE of β-Cu1.8Zn0.2V2O7 is produced by microstructures consisting of voids and anisotropic thermal deformation of crystal grains in ceramics. By reducing the size of the microstructures that produce NTE, large NTE equivalent to that of bulk was realized, even for ceramic particles of about 2 μm size. Comparison with particles produced using a conventional method demonstrates that the particle size distribution is narrow and that the particles are nearly spherical. This achievement is expected to pave the way to use of NTE materials in micrometer-scale control of thermal expansion. 相似文献
26.
Kaname Uno Shohei Iyoshi Masato Yoshihara Kazuhisa Kitami Kazumasa Mogi Hiroki Fujimoto Mai Sugiyama Yoshihiro Koya Yoshihiko Yamakita Akihiro Nawa Tomohiro Kanayama Hiroyuki Tomita Atsushi Enomoto Hiroaki Kajiyama 《International journal of molecular sciences》2022,23(8)
Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy and has a unique metastatic route using ascites, known as the transcoelomic root. However, studies on ascites and contained cellular components have not yet been sufficiently clarified. In this review, we focus on the significance of accumulating ascites, contained EOC cells in the form of spheroids, and interaction with non-malignant host cells. To become resistant against anoikis, EOC cells form spheroids in ascites, where epithelial-to-mesenchymal transition stimulated by transforming growth factor-β can be a key pathway. As spheroids form, EOC cells are also gaining the ability to attach and invade the peritoneum to induce intraperitoneal metastasis, as well as resistance to conventional chemotherapy. Recently, accumulating evidence suggests that EOC spheroids in ascites are composed of not only cancer cells, but also non-malignant cells existing with higher abundance than EOC cells in ascites, including macrophages, mesothelial cells, and lymphocytes. Moreover, hetero-cellular spheroids are demonstrated to form more aggregated spheroids and have higher adhesion ability for the mesothelial layer. To improve the poor prognosis, we need to elucidate the mechanisms of spheroid formation and interactions with non-malignant cells in ascites that are a unique tumor microenvironment for EOC. 相似文献
27.
Electron beam sterilization of cyclo olefin polymer leads to polymer degradation and production of alkyl radicals
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Hideaki Kiminami Yasufumi Imae Eiji Takahashi Hong Wei Satoshi Oomura Yoshihiko Abe 《应用聚合物科学杂志》2016,133(23)
We investigated the effects of electron‐beam (EB) sterilization on syringe barrels manufactured from cyclo olefin polymer (COP). The chemical structure of the polymer was determined by interpreting the 13C NMR and DEPT‐135 spectra of the COP resin. The antioxidants in the resin were identified by analyzing the liquid chromatography‐photo diode array‐mass spectrometry (LC‐PDA‐MS) data for the methanol extract of the resin and the gas chromatography‐mass spectrometry (GC‐MS) data for the supercritical methanol degradation products of the extract. NMR and LC‐PDA‐MS analyses revealed that EB sterilization produces degradation products in the COP main chain and reduces the quantity of the antioxidants in the COP resin. ESR spectra of the EB‐sterilized syringe barrels indicated the presence and location of alkyl radicals, which were generated in the COP main chain by EB sterilization. ESR analyses also indicated that the quantity of alkyl radicals decreased over time. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43498. 相似文献
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29.
Yoshihiko Okada Kaori Sasaki Baiqian Zhong Hideki Ishida Takeshi Mitsuda 《Journal of the American Ceramic Society》1994,77(5):1319-1323
A mixture of CaO and silicic acid prepared with a Ca/Si ratio of 2.0 was hydrothermally synthesized at 80° to 200°C, and the thermal decomposition behavior of the products (C-S-H with Ca(OH)2 ) was analyzed using XRD, 29 Si MAS NMR, and the trimethylsililation method (TMS). It was found that the main silicate anion structure of C-S-H was a mixture of a dimer and a single-chain polymer (larger than Si5 O16 ) and that polymerization advanced with an increase of the synthesizing temperature. On heating, the products decomposed to form β-C2 S. It was found that the decomposition was gradual and that the-higher the temperature of hydrothermal synthesis, the lower was the temperature of the decomposition into β-C2 S. Although the decomposition proceeded to form a monomer (β-C2 S) from the polymer and dimer, this dimer was resistant to heat and did not decompose unless heated to above 400°C. 相似文献
30.
Nanospheres of poly(lactide-co-glycolide) (PLGA), a biodegradable polymer, have been prepared using the conventional solvent diffusion method. In this study,
a method combining the solvent diffusion method and a two-step (premix) membrane emulsification technique is proposed for
the preparation of monodisperse PLGA nanospheres with a diameter of 200 nm. The monodispersity of the PLGA nanospheres was
higher than that of nanospheres obtained by the conventional solvent diffusion method. Generally, preparation of small particles
or droplets by the membrane emulsification technique requires a supply of high-pressure nitrogen gas to force the emulsion
or dispersion solution through the small pores of the membrane. However, in the technique proposed here, low-pressure nitrogen
gas (0.02–0.11 kgf/cm2) is sufficient. Thus, using this technique, one can obtain monodisperse PLGA nanospheres with a diameter of 200 nm in a relatively
short period of time under low-pressure nitrogen gas. 相似文献