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111.
Takayuki Tokoroyama Makoto Kamiya Noritsugu Umehara Chao Wang Dongfeng Diao 《Lubrication Science》2012,24(3):129-139
The influence of ultraviolet (UV) irradiation on low frictional performance of CNx coatings with 100 nm thickness having nitrogen contents of 9%, 14% and 19% deposited on Si(100) substrate by ion beam mixing was investigated in N2 atmosphere environment. Three UV lights of 254, 312 and 365 nm were used to irradiate the surface of CNx / Si(100) for 60 min. The changes of N / C ratio and atomic binding energy in the coating were analysed using Auger electron spectroscopy and X‐ray photoelectron spectroscopy, respectively. The friction coefficient of Si3N4 ball sliding against CNx was measured by a pin‐on‐disc tribometer, and wear tracks were analysed by the transmission electron microscope image. The results showed that UV irradiation on CNx coating can decrease the critical frictional cycles for low friction coefficient and that the mechanism is due to the formation of graphite‐like structure in the topmost CNx coating. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
112.
113.
Carbon nanofibers (CNFs) and carbon nanotubes (CNTs) are new carbon-based materials. However, the production of CNFs and CNTs is very difficult due to the complicated processes and high temperature involved. Therefore, a method of fabrication is required that enables high throughput at a low cost.Our previous study reported that oxygen ion beam energy of 500 eV applied to glassy carbon (GC) forms the finest pitch conical anti-reflection (AR) structures, and that an irradiation time of more than 24 min fabricates conical AR structures with heights of more than 250 nm. After the fabrication of the AR structures, irradiation by an argon ion (Ar+ beam changes the surface morphology, and oblique angle irradiation can form CNFs. Thus, we carried out oblique Ar+ beam irradiation on conical carbon protrusions on GC fabricated by oxygen ion beam irradiation. As a result, CNFs have been formed using oxygen and argon ion beam irradiation at room temperature. In addition, multi-wall CNT can be obtained by two-step ion beam irradiation. 相似文献
114.
Tomomasa Shinozaki Kenji Nomura Toshio Kamiya Masahiro Hirano Hideo Hosono 《Thin solid films》2010,518(11):2996-497
Epitaxial (0001) films of GaN were grown on (111) YSZ substrates using single-crystalline InGaZnO4 (sc-IGZO) lattice-matched buffer layers by molecular beam epitaxy with a NH3 source. The epitaxial relationships are (0001)GaN//(0001)IGZO//(111)YSZ in out-of-plane and [112¯0]GaN//[112¯0]IGZO//[11¯0]YSZ in in-plane. This is different from those reported for GaN on many oxide crystals; the in-plane orientation of GaN crystal lattice is rotated by 30° with respect to those of oxide substrates except for ZnO. Although these GaN films showed relatively large tilting and twisting angles, which would be due to the reaction between GaN and IGZO, the GaN films grown on the sc-IGZO buffer layers exhibited stronger band-edge photoluminescence than GaN grown on a low-temperature GaN buffer layer. 相似文献
115.
S. Shimizu T. Komaru K. Okawa M. Azuma T. Kamiya C. M. Fortmann I. Shimizu 《Solar Energy Materials & Solar Cells》2001,66(1-4)
Chlorinated intrinsic amorphous silicon films [a-Si:H(Cl)] and solar cell i-layers were fabricated using electron cyclotron resonance-assisted chemical vapor deposition (ECR-CVD) and SiH2Cl2 source gas. n–i–p solar cells deposited on ZnO–coated SnO2 substrates had poor photovoltaic performances despite the good electronic properties measured on the a-Si:H(Cl) films. Improved open–circuit voltage (Voc) of 0.84 V and fill factor (FF) of 54% were observed in n–i–p solar cells by providing an n/i buffer layer and by using Ga-doped ZnO coated glass substrates. However, the FF improvement was still rather poor, which is thought to originate from high interface recombination in the ECR deposited solar cells. The Voc and the FF showed much stable feature against light soaking. 相似文献
116.
Chirp and stability of mode-locked semiconductor lasers 总被引:1,自引:0,他引:1
A numerical study of mode-locked semiconductor lasers is presented with special attention to the chirp characteristics and to dispersion-related criteria for stable pulse-train emission. The dependence of the pulse chirp upon the refractive-index change, both with carrier density and carrier temperature changes, is discussed. The experimental observation of blue-chirped pulses for passive mode-locking in contrast to red-chirped pulses for active mode-locking is found to be due to the different contributions of gain and absorber media to the refractive-index change. In addition, it is revealed that the boundary of the stable operation regime is critically influenced by the spectral characteristics of laser and external cavity. Design considerations toward the achievement of high pulse energy, narrow spectral bandwidth, and linear chirp are given 相似文献
117.
Mayumi Komine Tuba Mussarat Ansary Md Razib Hossain Koji Kamiya Mamitaro Ohtsuki 《International journal of molecular sciences》2022,23(20)
COVID-19 is a recently emerged viral infection worldwide. SARS-CoV-2, the causative virus, is believed to have emerged from bat coronaviruses, probably through host conversion. The bat coronavirus which has the highest gene homology to SARS-CoV-2 specifically infects deep forest bats in China whose habitat extends through the Middle East to Southern Europe. Host conversion might have occurred due to the deforestation by humans exposing wild bats to the environment they had never encountered before. SARS-CoV-2 infects cells through two mechanisms: through its receptor ACE2 with the help of enzyme TMPRSS and through membrane fusion with the help of elastases in the inflammatory condition. Obesity, hypertension, diabetes mellitus, and pulmonary diseases cause poor prognosis of COVID-19. Aging is another factor promoting poor prognosis. These diseases and aging cause low-level and persistent inflammation in humans, which can promote poor prognosis of COVID-19. Psoriasis and atopic dermatitis are the major inflammatory skin diseases. These inflammatory skin conditions, however, do not seem to cause poor prognosis for COVID-19 based on the epidemiological data accumulated so far. These mechanisms need to be elucidated. 相似文献
118.
J. Takahashi M. Kuwayama H. Kamiya M. Takatsu T. Oota I. Yamai 《Journal of Materials Science》1988,23(1):337-342
Decomposition behaviours, including phase separation by the spinodal mechanism, were investigated for selected compositions ofx = 0.7, 0.5 and 0.3 in Ti
x
Sn1–x
O2 alloy. Inside the coherent spinodal, an equimolar alloy was found to decompose most rapidly at 1100° C and the decomposition rate decreased as the annealing temperature increased. The difference in the rate of decomposition outside the spinodal betweenx = 0.7 andx = 0.3 alloys suggested that the ionic mobility of diffusing tin was much slower than that of titanium in the alloy system. The effect of some dopants on the decomposition rate was also examined. Doping with tungsten or antimony atoms strongly suppressed the phase separation both inside and outside the spinodal, especially resulting in a prolonged stabilization ofx = 0.7 alloy. The role of the dopants in affecting the decomposition rate is discussed in relation to selective substitution of the doping atoms in the tin or titanium sublattice. 相似文献
119.
120.
Sorption and permeation of CO2 in poly(ethylene terephthalate) crystallized by sorption of high-pressure CO2 were examined below 1 atm at temperatures from 15 to 65°C. A large solubility and a high permeability of CO2 in this specimen were observed compared to poly(ethylene terephthalate) crystallized by thermal annealing to a similar degree. A large unrelaxed volume is expected to be left in the specimen after removal of high-pressure CO2 compared to the data of other PET samples. The thermal history during the measurements up to 65°C, which causes relaxation of the specimen, was shown to decrease CO2 solubility. On the other hand, permeation data after annealing show not only decreased permeability but also increased apparent diffusivity. The results mean a lower mobility of gases sorbed in the unrelaxed volume than that of ordinarily dissolved gases, which corresponds to the partial immobilization model. 相似文献