Engineering

67	Tanei, H.; Tanigaki, K.; Kusakabe, K.; Ogi, H.; Nakamura, N.; Hirao, M. (Graduate School of Engineering Science) Stacking-Fault Structure Explains Unusual Elasticity of Nanocrystalline Diamonds Applied Physics Letters, 94, 041914 (2009) In nanocrystalline diamond thin films, it is reported that the off-diagonal elastic constants are significantly larger than the bulk values. This letter reveals that the unusual elasticity is consistently explained by stacking fault inside the diamond grains instead of the graphitic plate inclusion, which was only possible mechanism. Ab initio calculation shows that stacking fault introduced in the diamond structure behaves as graphitic sp ² bonds, and the elastic constants calculated from the strain-energy relationship agree with the acoustic measurements.

68	Toyofuku, M.; Fujiwara, S.; Shin-ike, T.; Kuniyasu, H.; Kambe, N. (Graduate School of Engineering) Platinum-Catalyzed Intramolecular Vinylchalcogenation of Alkynes with β-Phenylchalcogeno Conjugated Amides Journal of the American Chemical Society, 130, 10504-10505 (2008) Simultaneous addition of carbon and heteroatom units to alkynes with the cleavage of carbon-heteroatom bond by transition metal complexes has been of great interest. However introduction of vinyl groups as carbon units remains as a challenging theme. We found that Pt(0) catalyzes intramolecular cis-vinylthiolation and –selenation of alkynes and developed a unique synthetic reaction that accomplishes effective construction of unsaturated six-membered lactam frameworks. Structure of a product was determined by X-ray analysis and a plausible reaction pathway was proposed.

69	Tsutsui, M.; Taniguchi, M.; Kawai, T. (Institute of Scientific and Industrial Research) Transverse Field Effects on DNA-Sized Particle Dynamics Nano Letters, 9(4), 1659-1662 (2009)

70	Tuan, L. Q.; Umakoshi, H.; Shimanouchi, T.; Kuboi, R. (Graduate School of Engineering Science) Liposome-Recruited Activity of Oxidized and Fragmented Superoxide Dismutase Langmuir, 24(2), 350-354 (2008) LIPOzyme ( lipo some + en zyme ) was developed by using the “break-down” type approach. The peptide fragment of H ₂ O ₂ -treated Cu,Zn-superoxide dismutase (SOD) was found to be reactivated with POPC liposome. The H ₂ O ₂ -treated (fragmented) SOD, which lost its activity and also secondary structure, was dramatically reactivated only by adding POPC liposomes, resulting in 1.3-2.8 times higher enzymatic activity. A comparison of the fractions detected in reverse-phase chromatography shows that specific SOD fragments could contribute to the induction of the SOD-LIPOzyme function.

71	Yamagami, R.; Kobayashi, K.; Tagawa, S. (Institute of Scientific and Industrial Research) Formation of Spectral Intermediate G-C and A-T Anion Complex in Duplex DNA Studied by Pulse Radiolysis Journal of the American Chemical Soeiety, 130(44), 14772-14777 (2008) In the early stages of radiation-induced DNA damage, high-energy radiation ionizes the nucleic acid bases, generating positive holes and electrons within the DNA strand. Identification of the DNA sites that trap these holes and electrons is essential to understanding the progression of radiation-induced damage. This paper describes the use of nanosecond pulse radiolysis to investigate the dynamics of electron adducts of oligonucelotides. The radical anions of the nucleotides were produced by the reaction of hydrated electrons and were protonated to form the corresponding neutral radicals.

72	Yamaguchi, A.; Shimizu, S.; Ishihara, Y.; Fujiwara, T. (Graduate School of Information Science and Technology) Bag-based Data Models for Incomplete Information and Their Closure Properties Journal of Intelligent Information Systems, 30, 115-135 (2008) In most practical database applications, incompleteness and duplication of facts should be carefully handled. We propose four bag-based data models for incomplete information. In the data models, incompleteness is represented by variables. Then we investigate the closure properties of forward and inverse algebraic operations (selection, projection, product, union, difference, and unique) on each of the data models. Moreover, for non-closed operations, we discuss the possibility of extending our data models so that the operations become closed.

73	Yamamoto T. ^1 ; Choi, M.-S. ^1 ; Majima, S. ^1 ; Fukuda, T. ^1 ; Kakeshita, T. ^1 ; Taguchi, E. ^2 ; Mori, H. ^2 ^1 (Graduate School of Engineering) ^2 (Research Center for Ultra-high Voltage Electron Microscopy) Iron Content and Temperature Dependence of Diffuse Scattering in Ti-(50-x)Ni-xFe (6≤x≤10) Alloys Philosophical Magazine, 88(7), 1027-1035 (2008) Electrical resistivity of Ti-(50-x)Ni-xFe (6≤x≤10) alloys exhibits a local minimum at T _min . In these alloys, diffuse scatterings appear below T _min at an incommensurate position of g+<ζζ0>, where g is a reciprocal lattice vector of the B2-phase and ζ~1/3. The value ζ increases with decreasing temperature and decreases with increasing Fe content. The value ζ at T _min agrees with the length of nesting vector obtained by a band calculation, suggesting that the diffuse scatterings are caused by the nesting effect of the Fermi surface in the B2-type structure.

74	Yokoyama, S.; Nakamura, R.; Nose, M.; Araki, T.; Yasui, T. (Graduate School of Engineering Science) Terahertz Spectrum Analyzer Based on a Terahertz Frequency Comb Optics Express, 16(17), 13052-13061 (2008) Precise frequency measurements of continuous-wave terahertz (THz) radiations are required to establish frequency metrology in the THz spectral region. We propose a THz-comb-referenced spectrum analyzer to measure the absolute frequency and spectral shape of continuous-wave THz radiation. Based on a stable frequency comb of photocarriers generated in a photoconductive antenna, the absolute frequency of test sources in sub-THz and THz regions was determined to a precision of a rubidium atomic clock. This spectrum analyzer has the potential to become a powerful tool for THz frequency metrology.

Back

5 of 5

share !