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91.
Shū Kobayashi Kentaro Kakumoto Yuichiro Mori Kei Manabe 《Israel journal of chemistry》2001,41(4):247-250
Asymmetric Michael reactions of ß-ketoesters with enones were effectively catalyzed by complexes of silver salts and BINAP derivatives in water. The reactions have proved to give Michael adducts in high yields with high enantioselectivities. These reactions are the first example of Lewis acid-catalyzed asymmetric Michael reactions in water. 相似文献
92.
Gang Huang Jiuhui Han Fan Zhang Ziqian Wang Hamzeh Kashani Kentaro Watanabe Mingwei Chen 《Advanced materials (Deerfield Beach, Fla.)》2019,31(2)
The key bottlenecks hindering the practical implementations of lithium‐metal anodes in high‐energy‐density rechargeable batteries are the uncontrolled dendrite growth and infinite volume changes during charging and discharging, which lead to short lifespan and catastrophic safety hazards. In principle, these problems can be mitigated or even solved by loading lithium into a high‐surface‐area, conductive, and lithiophilic porous scaffold. However, a suitable material that can synchronously host a large loading amount of lithium and endure a large current density has not been achieved. Here, a lithiophilic 3D nanoporous nitrogen‐doped graphene as the sought‐after scaffold material for lithium anodes is reported. The high surface area, large porosity, and high conductivity of the nanoporous graphene concede not only dendrite‐free stripping/plating but also abundant open space accommodating volume fluctuations of lithium. This ingenious scaffold endows the lithium composite anode with a long‐term cycling stability and ultrahigh rate capability, significantly improving the charge storage performance of high‐energy‐density rechargeable lithium batteries. 相似文献
93.
The importance of transparent conductive film is increasing due to its use in applications such as touch‐panel devices. Although indium tin oxide is widely used because of its high conductivity and transparency, conductive polymers are being studied as alternative materials that avoid the use of rare metals and the brittleness associated with existing systems. Polyethylene dioxythiophene (PEDOT)/polyethylene sulfonic acid (PSS) is drawing a lot of attention due to its well‐balanced conductivity, transparency, film formability, and chemical stability. The nonconductive PSS reportedly covers the conductive PEDOT. The PSS shell provides carrier and film‐formability to PEDOT but is also a barrier that hinders electrical conductivity. Therefore, the PEDOT film formability is explored supported by a substrate without the addition of PSS. The “hierarchical nanoporous layer glass” holds the PSS‐free PEDOT with its nanopores to form a homogeneous, transparent film. The PSS‐free PEDOT film thus achieves transparency of over 85% and resistivity of below 500 Ω sq?1. 相似文献
94.
Kenji Kinashi Hironori ShinkaiWataru Sakai Naoto Tsutsumi 《Organic Electronics》2013,14(11):2987-2993
Photorefractive (PR) performances of methyl-substituted poly(triarylamine) (PTAA)-based PR device were demonstrated using chemically modified electrodes (CMEs) of self-assembled monolayer (SAM) coated indium-tin-oxide (ITO) electrodes. The SAM-ITO electrodes successfully suppressed dark current which blocks the formation of space-charge field and also causes the dielectric breakdown. The PR device consisted of composite of PTAA, 4-azacycloheptylbenzylidenemalononitrile (7-DCST), N-ethylcarbazole (ECz), and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) sandwiched between the SAM-ITO electrodes. The PR devices showed the PR performances: optical gain Γ, refractive index Δn, diffraction efficiency η, response time τ, sensitivity S, phase shift Φ, trap-limited field Eq, number density of traps NT, and space-charge field ESC. The remarkable response time of 11.3 ms was achieved at the low electric field of 20 V μm−1, which was comparable to the response time of high-definition television (HDTV) quality of 16 ms. Our approach will widen the usage of higher mobility materials to photorefractive field and give us more favorable materials to achieve the best performance of photorefractivity in the future. 相似文献
95.
We present a method for combining two bilingual dictionaries to make a third, using one language as a pivot. In this case
we combine a Japanese-English dictionary with a Malay-English dictionary, to produce a Japanese-Malay dictionary. Our method
differs from previous methods in its improved matching through normalization of the pivot language. We have made a prototype
dictionary of around 76,000 Japanese-Malay pairs for 50,000 Japanese head words. 相似文献
96.
Tomoya Nagira Shugo Morita Hiroyoshi Yokota Hideyuki Yasuda Christopher M. Gourlay Masato Yoshiya Akira Sugiyama Kentaro Uesugi Akihisa Takeuchi Yoshio Suzuki 《Metallurgical and Materials Transactions A》2014,45(12):5613-5623
Synchrotron X-ray radiography at 125 frames per second was used to study deformation mechanisms in semi-solid Fe-C alloys at high solid fraction and shear strain rates of 10?1/s. An image correlation approach was also used to quantify the shear strain fields and study shear-induced dilation and the origin of shear cracking. It was shown that, at high solid fraction (90 to 93 pct solid), rearrangement including rotation and translation of solid particles became restricted and shear strain localized into narrow liquid-filled channels/fissures. Shear cracking was shown to originate from inadequate liquid flow into the expanding spaces between solid particles caused by shear-induced dilation. At lower solid fraction (~85 pct solid), solid particles rearranged with a significantly higher component of rotation leading to more shear-induced dilation and a wider shear band. 相似文献
97.
Shigeo Yamabe Kazuo Kobayashi-Hattori Kentaro Kaneko Hiroshi Endo Toshichika Takita 《Food chemistry》2007,100(1):369-374
To clarify the effect of soybean varieties on isoflavone, a useful component for human health, in soybean products, we investigated changes in the isoflavone content and composition in rice-koji miso, after fermentation/aging for 6 or 12 months using varieties of soybeans (Tohoku-126, Tohoku-135, Tohoku-139, Suzuyutaka and Chinese soybeans), by high performance liquid chromatography. In soybeans, the total isoflavone content in Tohoku-126 was 444 mg/100 g, which was 1.2–2.0 times the content in the other soybean varieties. The malonyl glycosides and aglycones in soybeans accounted for more than 60% and only a few percent, respectively. As for rice-koji miso, the total isoflavone and aglycone contents were the highest in miso prepared from Tohoku-126. The ratios of glycosides to aglycones (80.1–92.6%) in miso were higher than those in the original soybeans. The time course of the isoflavone composition during the fermentation/aging process of rice-koji miso indicated that glycosides decreased from 86.4% to 44.9% after 6 months but aglycones increased from 9.6% to 53.3%. 相似文献
98.
99.
A gold permanent magnet for an ornamental material is developed in the Au-Fe-Ni system. It is found that the magnetic properties of the An-12.5 wt% Fe-12.5 wt% Ni alloy aged at 450°C for seven hours and cold-swaged by 92 percent are Br = 0.53 T (5300 G), iHc = 40.8 kA/m (510 Oe), and (BH)max = 9.1 kJ/m3(1.1 MGOe). The Au-12.5 wt% Fe-10 wt% Ni-2.5 wt% Co alloy aged at 450°C for 2.5 h and swaged by 86 percent attained Br = 0.54 T (5400 G), iHc = 42.4 kA/m (530 Oe), and (BH)max = 9.6 kJ/m3 (1.2 MGOe). In these alloys, the magnetic hardening is due to the fine Fe-Ni rich ferromagnetic particles precipitated in the Au matrix. 相似文献
100.
A relationship between emission characteristics of Ba atom as an emitter material and temperature distributions of an electrode in a fluorescent lamp is described, which is measured by using laser-induced fluorescence and black-body radiation method, respectively. In a virgin lamp, a hot spot observed at the electrode edge connected to the power supply is the main source of Ba atom emission. In a long-term-used lamp, it is shown that Ba atom emission, thermionic electron emission in cathode half-cycle and electron collection in anode half-cycle are most active on the hot spot appearing on the center of the electrode. 相似文献