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Synthesis of Directly Connected BODIPY Oligomers through Suzuki–Miyaura Coupling
Hayashi, Yosuke,Yamaguchi, Shigeru,Cha, Won Young,Kim, Dongho,Shinokubo, Hiroshi American Chemical Society 2011 ORGANIC LETTERS Vol.13 No.12
<P>Treatment of a <I>meso</I>-arylboron dipyrrin (BODIPY) with NBS provides mono- and dibrominated BODIPYs at the 2- and 6-positions in excellent yields with high regioselectivity. Brominated products can be employed as a nice building block for the synthesis of a variety of BODIPY derivatives through Suzuki–Miyaura coupling. Because of a lack of substituents at the 1,3,5,7-positions, a directly β–β-linked BODIPY dimer exhibits a completely coplanar conformation of BODIPY units, offering effective π-conjugation.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/orlef7/2011/orlef7.2011.13.issue-12/ol200799u/production/images/medium/ol-2011-00799u_0001.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ol200799u'>ACS Electronic Supporting Info</A></P>
Variable speed control of weight stacks in 3 kN force standard machine
Toshiyuki Hayashi,Yoshihisa Katase,Hiroshi Maejima,Yukio Yamaguchi,Kazunaga Ueda 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
In calibrations of force measuring instruments using dead-weight type force standard machines, increasing the moving speed of dead-weights in linkage-weight stacks generally improves working efficiency but makes the calibration uncertainty worse due to oscillation of the weights. This conflict can be solved by introducing variable speed control of the linkage-weight stacks to drive the weights quickly in most loading/unloading processes and reduce the speed only when the moving weight comes close to a neighboring weight. Thus, variable speed control reduces the calibration time and prevents weight oscillation. The 3 kN dead-weight type force standard machine of NMIJ has already been equipped with AC servo motors for weight actuation, and variable speed control can be realized by modifying the existing control software. This report describes the design and results of the modification.
Masako Tada,Ayaka Hayashi,Yumi Asano,Musashi Kubiura-Ichimaru,Takamasa Ito,Miho Yoshii,Hiroshi Kimura,Yoichi Matsuda,Mitsuo Oshimura 한국유전학회 2021 Genes & Genomics Vol.43 No.3
Background DNA methylation is a signifcant epigenetic modifcation that is evolutionarily conserved in various species and often serves as a repressive mark for transcription. DNA methylation levels and patterns are regulated by a balance of opposing enzyme functions, DNA methyltransferases, DNMT1/3A/3B and methylcytosine dioxygenases, TET1/2/3. In mice, the TET enzyme converts DNA cytosine methylation (5mC) to 5-hydroxymethylcytosine (5hmC) at the beginning of fertilisation and gastrulation and initiates a global loss of 5mC, while the 5mC level is increased on the onset of cell differentiation during early embryonic development. Objective Global loss and gain of DNA methylation may be diferently regulated in diverged species. Methods Chicken B-cell lymphoma DT40 cells were used as an avian model to compare diferences in the overall regulation of DNA modifcation with mammals. Results We found that DNA methylation is maintained at high levels in DT40 cells through compact chromatin formation, which inhibits TET-mediated demethylation. Human and mouse chromosomes introduced into DT40 cells by cell fusion lost the majority of 5mC, except for human subtelomeric repeats. Conclusion Our attempt to elucidate the diferences in the epigenetic regulatory mechanisms between birds and mammals explored the evidence that they share a common chromatin-based regulation of TET–DNA access, while chicken DNMT1 is involved in diferent target sequence recognition systems, suggesting that factors inducing DNMT–DNA association have already diverged.
HIGH ANGULAR RESOLUTION [Fe II] λ1.644 μ SPECTROSCOPY OF YSOS WITH SUBARU TELESCOPE
PYO TAE-SOO,HAYASHI MASAHIKO,NAOTO KOBAYASHI,TERADA HIROSHI,TOKUNAGA ALAN T. The Korean Astronomical Society 2005 Journal of The Korean Astronomical Society Vol.38 No.2
We present results of the velocity-resolved spectroscopy of the [Fe II] $\lambda$1.644${\mu}m$ emission toward outflow sources with the Subaru Telescope at the angular resolution of 0.apos;16 ${\~}$ 0.apos;5 arcseconds. The observed sources are L1551 IRS 5, DG Tau, HL Tau and RW Aur, which are located in the Taurus-Aurigae Molecular Cloud, one of the closest star forming regions (0.apos;1 = 14 AU). We were able to resolve outflow structure in the vicinity of the sources at a scale of a few tens of AU. The position-velocity diagram of each object shows two velocity components: the high velocity component (HVC: 200 - 400 km $s^{-l}$) and the low velocity component (LVC: 50 - 150 km $s^{-l}$), which are clearly distinct in space and velocity. The HVC may be a highly collimated jet presumed from its narrow velocity width and high velocity. The LVC, on the other hand, may be a widely opened disk wind inferred from its broad velocity width and low velocity. The spectrum taken perpendicular to the L1551 IRS 5 outflow at its base shows that the LVC has a spatially wide subcomponent, supporting the above interpretation. We demonstrated that the [Fe II] 1.644 $\mu$ spectroscopy is a very powerful tool for the studies of fast jets and winds that directly emanate from star-disk systems.
Microstructure Control of Grain-oriented Barium-titanate Ceramics and Their Piezoelectric Properties
Petr Pulpan,Rintaro Mori,Hiroshi Hayashi,Yoshitaka Nagamori,Yuichi Yamamoto,Satoshi Wada 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.41
A templated grain growth (TGG) method was used for the preparation of grain-oriented bariumtitanate (BaTiO3, BT) ceramics. [110]-oriented BT plate-like template particles were dispersed in a matrix of hydrothermal BT spherical particles of various sizes. The Lotgering method using the Xray diffraction (XRD) pattern determined the degree of orientation along the [110] direction (F110). An optimization of the preparation conditions was performed in terms of the template-to-matrix weight ratio (T/M), the Ba/Ti ratio, and the sintering temperature and time in order to achieve a high F110 along with a small grain size and a high density. A grain size as small as 10 µm could be reached for Ba/Ti ratios close to the stoichiometric value. Lower values led to an increase in F110 and in the grain size. A T/M bigger than 80% was necessary for F110 to be above 80% and for the grain size lower than 40 µm. The density was almost independent of the T/M and the Ba/Ti ratios. The grain growth was limited by a two-step sintering process. Small grain size, high F110 and high density are essential if the piezoelectric constant d33 is to be increased above the values for standard BT ceramics.