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91.
Based on finite-difference time-domain(FDTD) method,the wave propagation and localization in two-dimensional defect-containing piezoelectric phononic crystals are investigated when the mechanical-electrical coupling is taken into account.The characteristics of localized defect modes are studied,and the effects of the number and direction of defects on the defect modes and transmission coefficients are discussed.Numerical results of defect modes and transmission coefficients are presented for BaTiO3/polymer piezocomposite,and from which we can see that the number and direction of defects have pronounced effects on the defect modes and transmission coefficients.The results also show the existence of elastic wave localization in piezoelectric phononic crystals containing defects. 相似文献
92.
To clarify the phenomenon of cavitation erosion in the sliding bearings of internal combustion engines, an apparatus was prepared and tests were conducted on cavitation in the oil between the cylindrical face of a rotating shaft and the tip of a horn attached to an ultrasonic oscillator. This apparatus produces an oil flow and a plus-minus oil pressure between a shaft and a horn tip to simulate erosion and its distribution on bearing surfaces.From patterns of cavitation erosion on the tip of a horn made of an Al-Sn alloy and the pressure distribution on the wedge oil film, it was determined that the region where cavitation bubbles occur and the region where erosion occurs owing to the collapse of the bubbles do not necessarily coincide.Cavitation erosion was found to occur in both the plus and the minus oil film pressure regions and erosion due to bubble collapse occurs in the regions where pressure increases in the direction of oil flow.The test results allow the postulation of the mechanism and the reasons for the occurrence of cavitation erosion on actual sliding bearing surfaces. 相似文献
93.
Biocatalytic Synthesis of Nitriles through Dehydration of Aldoximes: The Substrate Scope of Aldoxime Dehydratases
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Tobias Betke Jun Higuchi Philipp Rommelmann Keiko Oike Dr. Taiji Nomura Prof.Dr. Yasuo Kato Prof.Dr. Yasuhisa Asano Prof.Dr. Harald Gröger 《Chembiochem : a European journal of chemical biology》2018,19(8):768-779
Nitriles, which are mostly needed and produced by the chemical industry, play a major role in various industry segments, ranging from high‐volume, low‐price sectors, such as polymers, to low‐volume, high‐price sectors, such as chiral pharma drugs. A common industrial technology for nitrile production is ammoxidation as a gas‐phase reaction at high temperature. Further popular approaches are substitution or addition reactions with hydrogen cyanide or derivatives thereof. A major drawback, however, is the very high toxicity of cyanide. Recently, as a synthetic alternative, a novel enzymatic approach towards nitriles has been developed with aldoxime dehydratases, which are capable of converting an aldoxime in one step through dehydration into nitriles. Because the aldoxime substrates are easily accessible, this route is of high interest for synthetic purposes. However, whenever a novel method is developed for organic synthesis, it raises the question of substrate scope as one of the key criteria for application as a “synthetic platform technology”. Thus, the scope of this review is to give an overview of the current state of the substrate scope of this enzymatic method for synthesizing nitriles with aldoxime dehydratases. As a recently emerging enzyme class, a range of substrates has already been studied so far, comprising nonchiral and chiral aldoximes. This enzyme class of aldoxime dehydratases shows a broad substrate tolerance and accepts aliphatic and aromatic aldoximes, as well as arylaliphatic aldoximes. Furthermore, aldoximes with a stereogenic center are also recognized and high enantioselectivities are found for 2‐arylpropylaldoximes, in particular. It is further noteworthy that the enantiopreference depends on the E and Z isomers. Thus, opposite enantiomers are accessible from the same racemic aldehyde and the same enzyme. 相似文献
94.
Nakamori H Matsuyama S Imai S Kimura T Sano Y Kohmura Y Tamasaku K Yabashi M Ishikawa T Yamauchi K 《The Review of scientific instruments》2012,83(5):053701
To construct adaptive x-ray focusing optics whose optical parameters can be varied while performing wavefront correction, ultraprecise piezoelectric deformable mirrors have been developed. We computationally and experimentally investigated undesirable short-period deformation caused by piezoelectric actuators adhered to the substrate during mirror deformation. Based on the results of finite element method analysis, shape measurements, and the observation of x-ray reflection images, a guideline is developed for designing deformable mirrors that do not have short-period deformation errors. 相似文献
95.
K Eto Y Tsubamoto Y Terauchi T Sugiyama T Kishimoto N Takahashi N Yamauchi N Kubota S Murayama T Aizawa Y Akanuma S Aizawa H Kasai Y Yazaki T Kadowaki 《Canadian Metallurgical Quarterly》1999,283(5404):981-985
Glucose metabolism in glycolysis and in mitochondria is pivotal to glucose-induced insulin secretion from pancreatic beta cells. One or more factors derived from glycolysis other than pyruvate appear to be required for the generation of mitochondrial signals that lead to insulin secretion. The electrons of the glycolysis-derived reduced form of nicotinamide adenine dinucleotide (NADH) are transferred to mitochondria through the NADH shuttle system. By abolishing the NADH shuttle function, glucose-induced increases in NADH autofluorescence, mitochondrial membrane potential, and adenosine triphosphate content were reduced and glucose-induced insulin secretion was abrogated. The NADH shuttle evidently couples glycolysis with activation of mitochondrial energy metabolism to trigger insulin secretion. 相似文献
96.
Kazuhiro Nomura Kiyoshi Noro Yasuhisa Nakamura Yoshiteru Yazawa Hisao Yoshida Atsushi Satsuma Tadashi Hattori 《Catalysis Letters》1998,53(3-4):167-169
The examination of the combustion of a trace amount of methane over Pd‐ion‐exchanged silicoaluminophosphate‐5 (Pd‐SAPO‐5)
at low temperature in the presence of water vapor reveals that water vapor strongly depresses methane combustion and causes
a significant decrease in catalytic activity with time. The newly prepared bimetallic catalyst Pd–Pt‐SAPO‐5, on the other
hand, shows higher performance for methane combustion under similar conditions.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
97.
Segawa M. Ono M. Musha S. Kishimoto Y. Ohashi A. 《Advanced Packaging, IEEE Transactions on》1999,22(2):160-165
The world's smallest (105×55×20 mm) and lightest (130 g) digital still camera has been developed, in which a 330 K pixel complementary metal-oxide-semiconductor (CMOS) image sensor chip is used as an image sensor. The authors have developed a new thinner and smaller image sensor module, called tape automated bonding (TAB) on glass (TOG) module, using the anisotropic conductive paste (ACP) interconnection method. The TOG production process was established by obtaining optimum bonding conditions for both optical glass bonding and CMOS chip bonding to the TAB tape. The bonding conditions including sufficient bonding margins, were mainly studied. The TOG module obtained good imaging properties, It also has a high reliability such as thermal cycle test (-40 to +110°C/30 min, 2000 cycles) and the high temperature storage test (60°C, 90% RH, 3000 h). The stable production process was confirmed by fabricating an automatic bonding machine 相似文献
98.
Photochemical and photoelectrochemical properties of ruthenium tris(2,2′-bipyridine) (Ru2+)-viologen (V2+) linked disulfides [RuCnVC6S]2 (n (number of methylene groups)=3, 7) with different spacer-chain lengths and Ru2+ disulfides [RuCmS]2 (m=13, 17) were compared. The luminescence intensity in CH3CN was in the order of [RuC13S]2≈[RuC17S]2>[RuC7VC6S]2[RuC3VC6S]2, implying efficient photoinduced electron-transfer between Ru2+ and V2+ moieties in the linked compounds. The monolayer assembly of the compound was fabricated on a gold surface. In the presence of triethanolamine, the anodic photocurrent was clearly observed from the RuCnVC6S/Au (n=3, 7) electrode (gold electrode modified with [RuCnVC6S]2), and its intensity was substantially larger for n=7 than for n=3. Photocurrent action spectra for the RuCnVC6S/Au (n=3, 7) electrodes were well correlated with the corresponding electronic absorption spectra in solution. The photocurrent from the RuC7VC6S/Au electrode was reduced more effectively by the coexistence of a water-soluble viologen as compared with the RuC3VC6S/Au electrode. The photocurrent from the RuCmS/Au (m=13, 17) electrode was very small. The results suggest that the spacer-chain length between the Ru2+ and the V2+ moieties profoundly affects the Ru2+-sensitized photocurrent. 相似文献
99.
Kazuhiro Nomura Kiyoshi Noro Yasuhisa Nakamura Hisao Yoshida Atsushi Satsuma Tadashi Hattori 《Catalysis Letters》1999,58(2-3):127-130
Combustion of a trace amount of CH4 over Pd catalysts supported on calcined ZrO2 was examined under nearly exhaust gas conditions where the temperature is not so high and water vapor coexists. High catalytic
activity was obtained with ZrO2 support calcined at 1073 and 1273 K. The durability test at 673 K for 100 h revealed that the activity of these catalysts
hardly decreased, while that of the Pd catalysts supported on calcined Al2O3 were much decreased in the course of time. These results demonstrated the advantages of ZrO2 as a support for Pd catalysts in the present reaction.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
100.
Kazuhiro Mizuno Hiroyuki Katsukawa Yasuhisa Sakurai Naoki Tanaka 《Electrical Engineering in Japan》1997,119(2):10-17
A new fault location system using optical current transducers (CTs) to detect faulted sections in the bus bars of directly grounded 275-kV substations has been developed. This system detects fault current by combining optical CTs with wound-type CTs. The new type of optical CT applies a bulk-type Faraday sensor to the combination of windings around a magnetic iron core and a solenoid coil. The optical CT was capable of current measuring over 50 kA. A current differential discriminator combining an optical CT and a wound-type CT verified the operational performance with 40-kA currents. The intended level of fault detection performance was obtained. Based on these results, a system is being made for actual application in 275-kV substations. © 1997 Scripta Technica, Inc. Electr Eng Jpn 119(2): 10–17, 1997 相似文献