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排序方式: 共有1878条查询结果,搜索用时 859 毫秒
1.
Lili Hao Jiaxiang Li Peng Wang Zongliang Wang Zhenxu Wu Yu Wang Zixue Jiao Min Guo Tongfei Shi Qigang Wang Yoshihiro Ito Yen Wei Peibiao Zhang 《Advanced functional materials》2021,31(15):2009661
The degradation behavior of implants is significantly important for bone repair. However, it is still unprocurable to spatiotemporally regulate the degradation of the implants to match bone ingrowth. In this paper, a magneto-controlled biodegradation model is established to explore the degradation behavior of magnetic scaffolds in a magnetothermal microenvironment generated by an alternating magnetic field (AMF). The results demonstrate that the scaffolds can be heated by magnetic nanoparticles (NPs) under AMF, which dramatically accelerated scaffold degradation. Especially, magnetic NPs modified by oleic acid with a better interface compatibility exhibit a greater heating efficiency to further facilitate the degradation. Furthermore, the molecular dynamics simulations reveal that the enhanced motion correlation between magnetic NPs and polymer matrix can accelerate the energy transfer. As a proof-of-concept, the feasibility of magneto-controlled degradation for implants is demonstrated, and an optimizing strategy for better heating efficiency of nanomaterials is provided, which may have great instructive significance for clinical medicine. 相似文献
2.
A highly transparent and thermally stable copolymer of 1‐adamantyl methacrylate and styrene
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Thermal and optical properties of copolymers of 1‐adamantyl methacrylate (AdMA) and styrene (St) prepared by free radical polymerization in the bulk are investigated. The copolymer forms an azeotrope when the composition is AdMA/St = 55/45 mol%. The glass transition temperature and decomposition temperature of the azeotropic copolymer are 170 and ca 340 °C, respectively. The refractive index increases nonlinearly with St content from 1.522 to 1.591. The light scattering loss at 633 nm is 28.1 dB km?1, which is less than half of that of polystyrene. The total optical loss including molecular vibrational absorption, which is evaluated using a copolymer‐based optical fiber, is 292–645 dB km?1 at 500–700 nm. These values correspond to transmittances of 86–93% for a 1 m optical path length. © 2014 Society of Chemical Industry 相似文献
3.
Taro Shimonosono Yoshihiro Hirata Mubin Changgan Syohei Kamei Rina Tokaiya Soichiro Sameshima Toshifumi Yoshidome Katsuhiko Yamaji 《Ceramics International》2018,44(8):8904-8912
This paper reports the performance of porous Gd-doped ceria (GDC) electrochemical cells with Co metal in both electrodes (cell No. 1) and with Ni metal in the cathode and Co metal in the anode (cell No. 2) for CO2 decomposition, CH4 decomposition, and the dry reforming reaction of a biogas with CO2 gas (CH4 + CO2 → 2H2 + 2CO) or with O2 gas in air (3CH4 +?1.875CO2 +?1.314O2 → 6H2 +?4.875CO +?0.7515O2). GDC cell No. 1 produced H2 gas at formation rates of 0.055 and 0.33?mL-H2/(min?m2-electrode) per 1?mL-supplied gas/(min?m2-electrode) at 600?°C and 800?°C, respectively, by the reforming of the biogas with CO2 gas. Similarly, cell No. 2 produced H2 gas at formation rates of 0.40?mL-H2/(min?m2) per 1?mL-supplied gas/(min?m2) at 800?°C from a mixture of biogas and CO2 gas. The dry reforming of a real biogas with CO2 or O2 gas at 800?°C proceeded thermodynamically over the Co or Ni metal catalyst in the cathode of the porous GDC cell. Faraday's law controlled the dry reforming rate of the biogas at 600?°C in cell No. 2. This paper also clarifies the influence of carbon deposition, which originates from CH4 pyrolysis (CH4 → C + 2H2) and disproportionation of CO gas (2CO → C + CO2), on the cell performance during dry reforming. The dry reforming of a biogas with O2 molecules from air exhibits high durability because of the oxidation of the deposited carbon by supplied air. 相似文献
4.
Mechanisms of orientational and photoelastic birefringence generation of methacrylates for the design of zero–zero‐birefringence polymers
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Houran Shafiee Shotaro Beppu Shuhei Iwasaki Akihiro Tagaya Yasuhiro Koike 《Polymer Engineering and Science》2015,55(6):1330-1338
The intrinsic birefringence Δn0 and photoelastic coefficient C of poly(methyl methacrylate), poly(2,2,2‐trifluroethyl methacrylate), poly(phenyl methacrylate), and poly(2,2,3,3,3‐pentafluorophenyl methacrylate) were determined. We categorized these methacrylate polymers into four birefringence‐types, even though their molecular structures differed only by the substituents on the side chains. Based on the results of Δn0 and C, novel polymers that exhibit neither orientational nor photoelastic birefringence, i.e., zero–zero‐birefringence polymers, were designed and synthesized by quaternary copolymerization system. Furthermore, we confirmed that the mechanisms of orientational birefringence and photoelastic birefringence generation were different in these methacrylate polymers. The conformation of the repeat unit of the polymers was nearly constant during the generation of orientational birefringence. In contrast, the conformation of the repeat unit of the polymers changed during the generation of photoelastic birefringence in the glassy state. These findings demonstrated the reasonability of evaluating orientational and photoelastic birefringence separately, as well as the adequacy of the classification of polymers into four birefringence‐types. Given these results and the fact that zero–zero‐birefringence polymers could be prepared successfully by four‐birefringence type monomers, we demonstrated the reasonability of the method for designing the zero–zero‐birefringence polymers. POLYM. ENG. SCI., 55:1330–1338, 2015. © 2015 Society of Plastics Engineers 相似文献
5.
Yoshihiro Iida Toshikatsu Tsuyuki Takao Mashima Takeo Takashima Kunito Okuyama 《亚洲传热研究》2002,31(1):28-41
This paper presents a series of experimental results on a passive augmentation technique of boiling heat transfer by supplying solid particles in liquid. A cylindrical heater 0.88 mm in diameter is placed in saturated water, in which a lot of mobile particles exist, and the nucleate and film boiling heat transfer characteristics are measured. Particle materials used were alumina, glass, and porous alumina, and the diameter ranged from 0.3 mm to 2.5 mm. Particles are fluidized by the occurrence of boiling without any additive power, and the heat transfer is augmented. The maximum augmentation ratio obtained in this experiment reaches about ten times the heat transfer coefficient obtained in liquid alone. The augmentation ratio is mainly affected by the particle material, diameter, and the height of the particle bed set at no boiling condition. The augmentation mechanism is discussed on the basis of the experimental results. © 2001 Scripta Technica, Heat Trans Asian Res, 31(1): 28–41, 2002 相似文献
6.
Yoshihiro Yajima 《时间序列分析杂志》1985,6(3):187-201
Abstract. We shall investigate the asymptotic behaviour of the sample autocorrelations and partial autocorrelations of a multiplicative ARIMA process and derive their limiting distributions. Some simulations are presented to illustrate the results obtained. 相似文献
7.
A newly developed graded-index polymer optical fiber (GI-POF) with high-temperature and high-humidity stability was proposed. As it was found that the high numerical aperture and high glass transition temperature (T/sub g/) at the core center of the GI-POF were key issues to achieve both high-temperature and humidity stability, a partially fluorinated polymer material was adopted to obtain both characteristics in the GI-POF. The newly developed GI-POF had low-loss (140 dB/km at 650-nm wavelength), high-bandwidth (higher than 1 GHz for 100 m transmission), high-temperature and humidity stability at 70/spl deg/C, 80% relative humidity (R.H.) and low bending loss. 相似文献
8.
Hideo Sawada Hiroshi Kakehi Masashi Koizumi Yoshihiro Katoh Masashi Miura 《Journal of Materials Science》2007,42(17):7147-7153
Fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomer [RF-(DOBAA)
n
-RF] reacted with tetraethoxysilane (TEOS) and silica nanoparticles in the presence of low-molecular weight biocides such as
hibitane, hinokitiol, and hinokioil under alkaline conditions to afford RF-(DOBAA)
n
-RF/silica nanocomposites-encapsulated these biocides in excellent to moderate isolated yields. Fluoroalkyl end-capped N,N-dimethylacrylamide oligomer [RF-(DMAA)
n
-RF] and acrylic acid oligomer [RF-(ACA)
n
-RF]/silica nanocomposites-encapsulated hibitane were obtained under similar conditions. Dynamic light scattering measurements
showed that the size of these fluorinated nanocomposites-encapsulated biocides thus obtained is nanometer size-controlled.
Additionally, these fluorinated nanocomposites were shown to have a good dispersibility and stability in methanol and water.
Of particular interest, these fluorinated nanocomposites-encapsulated biocides were found to have a good antibacterial activity
against Staphylococcus aureus, and these nanocomposites were applied to the surface modification of traditional organic polymers such as poly(methyl methacrylate). 相似文献
9.
Takeshi Shiofuku Norihiro Abe Yoshihiro Tabuchi Hirokazu Taki Shoujie He 《Artificial Life and Robotics》2008,13(1):290-293
This paper presents an approach of measuring in real-time the vector of finger that is pointing to an object. DSP is used
in the operation processing unit in order to do the real-time processing. The steps include the extraction of flesh-colored
regions from an image, the labeling of the flesh-colored regions, and the detection of two characteristic positions on the
finger so that the direction that the finger is pointing at will be calculated. The entire process takes about 29 msec, which
makes it possible to have the frame rate of 34 fps. With this frame rate, this measurement approach is considered real-time
and promising to be merged into other application systems.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
10.
Masatsune Kato Takaaki Aoki Takashi Noji Yasuhiro Ono Yoji Koike Tomoyuki Hikita Yoshitami Saito 《Journal of Superconductivity and Novel Magnetism》1994,7(1):37-38
We have investigated the relation between the crystal structure and superconductivity in La1.9Bi0.1CuO4+δ , in which the phase separation observed in La2CuO4+δ is suppressed. A phase diagram in theT?δ plane is given for La1.9Bi0.1CuO4+δ with excess oxygen. For very smallδ values, the crystal structure is orthorhombic, and an orthorhombic-tetragonal phase transition occurs markedly atδ ~ 0.03 in the measured temperature range between 13 and 293 K. Superconductivity is observed in the range of 0.04<δ<0.11. This is clear evidence thathigh-T c superconductivity also appears in the tetragonal phase. 相似文献