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151.
Vast literature is available for modeling the coupled fluid structure interaction involving the flow of a pulsatile fluid through pipes/shells under ambient temperature. In contrast it is found that there is no literature on such problems under the influence of temperature. This paper considers the evaluation of dynamic instability regions due to a flow of pulsating hot fluid through an insulated composite cylindrical shell. A coupled fluid structure interaction model in conjunction with uncoupled thermomechanical model is used for analysis. The system's equations of motion containing periodic coefficients are expressed in modal domain considering linear transformation. Fourth order Runge–Kutta method using Gill's coefficient is adopted to compute the state transition matrix which provides the stability information of the periodic system following the Floquet–Liapunov theory. Pulsatile flow of water at various magnitude of steady state temperature is considered and hence the effect of water temperature on the instability regions is analyzed. The influence of lamina fibre angle on the instability regions is also examined. 相似文献
152.
Masaki Taneike Kota Sawada Fujio Abe 《Metallurgical and Materials Transactions A》2004,35(4):1255-1262
The distributions and precipitated amounts of M23C6 carbides and MX-type carbonitrides with decreasing carbon content from 0.16 to 0.002 mass pct in 9Cr-3W steel, which is used
as a heat-resistant steel, has been investigated. The microstructures of the steels are observed to be martensite. Distributions
of precipitates differ greatly among the steels depending on carbon concentration. In the steels containing carbon at levels
above 0.05 pct, M23C6 carbides precipitate along boundaries and fine MX carbonitrides precipitate mainly in the matrix after tempering. In 0.002
pct C steel, there are no M23C6 carbide precipitates, and instead, fine MX with sizes of 2 to 20 nm precipitate densely along boundaries. In 0.02 pct C steel,
a small amount of M23C6 carbides precipitate, but the sizes are quite large and the main precipitates along boundaries are MX, as with 0.002 pct
C steel. A combination of the removal of any carbide whose size is much larger than that of MX-type nitrides, and the fine
distributions of MX-type nitrides along boundaries, is significantly effective for the stabilization of a variety of boundaries
in the martensitic 9Cr steel. 相似文献
153.
Jiyoung Kim Min Sung Choi Kang Ho Shin Manikantan Kota Yingbo Kang Soojung Lee Jun Young Lee Ho Seok Park 《Advanced materials (Deerfield Beach, Fla.)》2019,31(34)
Electrochemical sodium storage and capture are considered an attractive technology owing to the natural abundance, low cost, safety, and cleanness of sodium, and the higher efficiency of the electrochemical system compared to fossil‐fuel‐based counterparts. Considering that the sodium‐ion chemistry often largely deviates from the lithium‐based one despite the physical and chemical similarities, the architecture and chemical structure of electrode materials should be designed for highly efficient sodium storage and capture technologies. Here, the rational design in the structure and chemistry of carbon materials for sodium‐ion batteries (SIBs), sodium‐ion capacitors (SICs), and capacitive deionization (CDI) applications is comprehensively reviewed. Types and features of carbon materials are classified into ordered and disordered carbons as well as nanodimensional and nanoporous carbons, covering the effect of synthesis parameters on the carbon structure and chemistry. The sodium storage mechanism and performance of these carbon materials are correlated with the key structural/chemical factors, including the interlayer spacing, crystallite size, porous characteristics, micro/nanostructure, morphology, surface chemistry, heteroatom incorporation, and hybridization. Finally, perspectives on current impediment and future research directions into the development of practical SIBs, SICs, and CDI are also provided. 相似文献
154.
Yuji Hiruma Kota Marumo Rintaro Aoyagi Hajime Nagata Tadashi Takenaka 《Journal of Electroceramics》2008,21(1-4):296-299
Bismuth potassium titanate, (Bi1/2K1/2)TiO3 (BKT), ceramics were prepared by the hot-pressing (HP) method without dopant and with dopants of Bi2O3, La2O3 and MnCO3. The relative density of BKT ceramics hot-pressed at 1,060 and 1,080 °C (hereafter abbreviated to BKT-HP1060°C and BKT-HP1080°C) and x mass% Bi2O3, La2O3 and MnCO3 doped BKT ceramics hot-pressed at 1,060 °C (hereafter abbreviated as BKTBix; x?=?0.1–0.6, BKTLax; x?=?0.1–0.6 and BKTMnx; x?=?0.1–0.3) were all higher than 97%. In this study, the ferroelectric properties of BKT ceramics were successfully obtained, and the remanent polarization P r and coercive field E c of BKT-HP1080°C were 22.2 μC/cm2 and 52.5 kV/cm, respectively. A small amount of La tends to increase P r, and the P r of BKTLa0.1 was 19.2 μC/cm2. The piezoelectricities were improved to optimize poling conditions, and the electromechanical coupling factor k 33 and piezoelectric constant d 33 of BKT-HP1080°C were 0.34 and 82.8 pC/N, respectively. 相似文献
155.
Kota Fukaya Koichi Sasaki Taishi Kimura Masumi Inoue Hideo Sugai 《Thin solid films》2009,517(8):2762-2766
We correlated the crystallinity of YBaCuO films prepared by magnetron sputtering deposition using Ar/O2 mixture gas with the atomic and molecular composition in the gas phase. YBaCuO films were deposited on MgO substrates at 670 °C. Two-dimensional distributions of Y, Ba, Cu, YO, BaO, and CuO densities and one-dimensional distribution of O density were measured by laser-induced fluorescence spectroscopy. The Y and Ba densities decreased significantly with the increase of the O2 partial pressure, and they were below the detection limit at an O2 flow ratio of 10% and a total gas pressure of 53 Pa. The decrease in the Y and Ba densities was compensated by an increase in the YO and BaO densities. The decrease in the Cu density with the increase of the O2 partial pressure was less significant, while the CuO density was below the detection limit at all the discharge conditions. The O density was evaluated to be 1012-1013 cm− 3, which was much higher than the Cu density. On the other hand, YBaCuO films with high crystallinity were obtained at total gas pressures of 53-80 Pa and O2 flow ratios of 50-70%. Therefore, it is concluded that the precursors for the deposition of YBaCuO films with high crystallinity are Cu, YO, BaO, and O. 相似文献
156.
A procedure for the topology design of compliant mechanisms with multiple output requirements is presented. Two methods for handling the multiple output requirements are developed, a combined virtual load method and a weighted sum of objectives method. The problem formulations and numerical solution procedures are discussed and illustrated by design examples. The examples illustrate the capabilities of the design procedure, the effect of the direction of the output deflection requirements on the solution, as well as computational issues such as the effect of the starting point and effect of the material resource constraint. 相似文献
157.
Xinbao Liu Mitsuharu Shiwa Kota Sawada Hisashi Yamawaki Makoto Watanabe 《Materials Letters》2010,64(11):1247-1250
In this work, the internal friction of 2.25Cr-1Mo steel measured on a dynamic mechanical analyzer (DMA) was used to evaluate its thermal diffusivity at elevated temperatures. With the dual cantilever clamp, the internal friction of 2.25Cr-1Mo steel at high temperatures was obtained, which was mainly composed of the thermoelastic relaxation with a peak of 15 Hz and the broad spectrum of relaxation processes especially at low frequencies. According to the deconvolution of these results, the thermoelastic internal friction of 2.25Cr-1Mo steel at high temperatures was achieved. Then, the thermal diffusivity of 2.25Cr-1Mo steel at high temperatures was quantitatively estimated, which confirmed the validity of present method. 相似文献
158.
Kotone Naitoh Yuta Orihara Hiroshi Sakagami Takumi Miura Keitaro Satoh Shigeru Amano Kenjiro Bandow Yosuke Iijima Kota Kurosaki Yoshihiro Uesawa Masashi Hashimoto Hidetsugu Wakabayashi 《International journal of molecular sciences》2022,23(5)
Background: Very few papers covering the anticancer activity of azulenes have been reported, as compared with those of antibacterial and anti-inflammatory activity. This led us to investigate the antitumor potential of fifteen 4,6,8-trimethyl azulene amide derivatives against oral malignant cells. Methods: 4,6,8-Trimethyl azulene amide derivatives were newly synthesized. Anticancer activity was evaluated by tumor-specificity against four human oral squamous cell carcinoma (OSCC) cell lines over three normal oral cells. Neurotoxicity was evaluated by cytotoxicity against three neuronal cell lines over normal oral cells. Apoptosis induction was evaluated by Western blot and cell cycle analyses. Results: Among fifteen derivatives, compounds 7, 9, and 15 showed the highest anticancer activity, and relatively lower neurotoxicity than doxorubicin, 5-fluorouracil (5-FU), and melphalan. They induced the accumulation of a comparable amount of a subG1 population, but slightly lower extent of caspase activation, as compared with actinomycin D, used as an apoptosis inducer. The quantitative structure–activity relationship analysis suggests the significant correlation of tumor-specificity with a 3D shape of molecules, and possible involvement of inflammation and hormone receptor response pathways. Conclusions: Compounds 7 and 15 can be potential candidates of a lead compound for developing novel anticancer drugs. 相似文献
159.
160.
Yuan Liu Susumu Tsukamoto Kota Sawada Fujio Abe 《Metallurgical and Materials Transactions A》2014,45(3):1306-1314
Microstructure evolution of newly developed 9Cr-3W-3Co-V, Nb steel with boron addition (B steel) has been analyzed during HAZ thermal cycle at the peak temperature of around Ac3 (Ac3 HAZ) and post-weld heat treatment (PWHT) to elucidate the prevention mechanism of type IV failure by boron addition. It was found that enhancement of the boundary strengthening by precipitates is the main reason for prevention of type IV failure by boron addition. In B steel HAZ, original austenite is reconstituted through martensitic α to γ reverse transformation during the heating and original martensite is reconstituted through martensitic transformation during cooling of the Ac3 HAZ thermal cycle. This process allows M23C6 carbides to precipitate at the prior austenite grain (PAG) and block boundaries during PWHT even if the chemical segregation of carbide forming elements exists. The effect of boundary strengthening on the creep property has also been investigated. Microstructure evolution during creep was compared among Gr.92 with different Ac3 HAZ microstructures prepared by three kinds of heat treatments and B steel. The results revealed that both the boundary length and kernel average misorientation value decreased in all samples during creep. However, this process occurred very rapidly in Ac3 HAZ simulated Gr.92, whereas it was significantly retarded in the other samples with sufficient boundary strengthening by precipitates. This result confirms that the precipitates formed at PAG and block boundaries play the most important role to stabilize the microstructure of Ac3 HAZ simulated samples during creep and prolong the creep life. 相似文献