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排序方式: 共有621条查询结果,搜索用时 59 毫秒
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Dr. Yogesh Kumar Maurya Dr. Pingchun Wei Takahide Shimada Dr. Kazuhisa Yamasumi Dr. Shigeki Mori Prof. Dr. Ko Furukawa Dr. Hajime Kusaba Prof. Dr. Tatsumi Ishihara Prof. Dr. Yongshu Xie Dr. Masatoshi Ishida Prof. Dr. Hiroyuki Furuta 《化学:亚洲杂志》2021,16(7):743-747
A facile synthetic strategy towards conformationally stable chiral chromophores based on dimeric porphyrinoids has been established. A peculiar class of face-to-face intramolecularly interlocked corrole dimers were formed by the oxidative C−C coupling linked at the inner carbon sites upon simple treatment of copper(II) ions. Their intrinsic electronic structures were modulated by the peripheral corrole ring annulations, which lead to distinct optical properties and redox profiles. The stereogenic carbon centers implemented in the confused corrole skeleton provided a rationale for designing novel chiral materials. 相似文献
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Total Synthesis and Biological Evaluation of the Antibiotic Lysocin E and Its Enantiomeric,Epimeric, and N‐Demethylated Analogues 下载免费PDF全文
Dr. Motoki Murai Takuya Kaji Dr. Takefumi Kuranaga Dr. Hiroshi Hamamoto Prof. Dr. Kazuhisa Sekimizu Prof. Dr. Masayuki Inoue 《Angewandte Chemie (International ed. in English)》2015,54(5):1556-1560
Lysocin E, a macrocyclic peptide, exhibits potent antibacterial activity against methicillin‐resistant Staphylococcus aureus (MRSA) through a novel mechanism. The first total synthesis of lysocin E was achieved by applying a full solid‐phase strategy. The developed approach also provides rapid access to the enantiomeric, epimeric, and N‐demethylated analogues of lysocin E. Significantly, the antibacterial activity of the unnatural enantiomer was comparable to that of the natural isomer, suggesting the absence of chiral recognition in its mode of action. 相似文献
5.
Melting characteristics of phase change material by natural convection heat transfer inside horizontal rectangular capsules are examined experimentally. The capsules are heated isothermally and three kinds of aspect ratios (qH/W=3, 1 and 1/3) are provided. Octadecane and ice are used, respectively, as the phase change material. A method of analysis applying the empirical correlations for natural convection heat transfer in a vertical or horizontal enclosure to the melting in the rectangular capsules is presented. The predicted results show good agreement with the experimental data. For the melting of octadecane and ice, it is found that the effect of aspect ratio on the melting process is not significant for the range ofB=1/3 to 3. 相似文献
6.
In recent years, the hole drilling method for determining residual stresses has been implemented with optical methods such
as holographic interferometry and ESPI to overcome certain limitations of the strain rosette version of hole drilling. Although
offering advantages, the interferometric methods require vibration isolation, a significant drawback to their use outside
of the laboratory. In this study, a 3D image correlation approach was used to measure micron-sized surface displacements caused
by the localized stress relief associated with hole drilling. Residual stresses were then found from the displacements using
non-dimensional relations previously derived by finite element analysis. A major advantage of image correlation is that it
does not require interferometric vibration isolation. Experiments were performed to check the ability of this new approach
for uniaxial and equi-biaxial states of stress. Stresses determined by the approach were in good agreement with computed values
and those determined by hole drilling using holographic interferometry. 相似文献
7.
Kazuhisa Sato Shunya Tashiro Shuhei Matsunaga Yohei Yamaguchi Takanori Kiguchi Toyohiko J. Konno 《哲学杂志》2018,98(21):1945-1960
We have studied three-dimensional (3D) structures and growth processes of 14H-type long-period stacking order (LPSO) formed in Mg97Zn1Gd2 cast alloys by single tilt-axis electron tomography (ET) using high-angle annular dark-field scanning transmission electron microscopy. Evolution of the solute-enriched stacking faults (SFs) and the 14H LPSO by ageing were visualised in 3D with a high spatial resolution in multi-scale fields of views from a few nanometres to ~10 μm. Lateral growth of the solute-enriched SFs and the LPSO in the (0?0?0?1)Mg plane is notable compared to the out-of-plane growth in the [0?0?0?1]Mg direction. The 14H LPSO grows at the cost of decomposition of the (Mg, Zn)3Gd-type precipitates, and accompany a change of in-plane edge angles from 30 to 60°. We have updated the Time–Temperature–Transformation diagram for precipitation in Mg97Zn1Gd2 alloys: starting temperatures of both solute-enriched SFs and LPSO formation shifted to a shorter time side than those in the previous diagram. 相似文献
8.
Nobuhiro ShionozakiToru Yamaguchi Hiroyuki KitanoMitsutaka Tomizawa Kimiko Makino Hiromi Uchiro 《Tetrahedron letters》2012,53(38):5167-5170
Total synthesis of an antitumor compound myceliothermophin A and related compounds based on a convergent synthetic strategy was investigated. A common decalin skeleton of myceliothermophins was stereoselectively constructed by an IMDA reaction. The fully elaborated precursor of myceliothermophins was obtained via aldol reaction of N-protected γ-methoxylactam with decalin aldehyde. By using Teoc group for the protection of nitrogen atom of lactam ring, selective deprotection prior to the hydrolysis of methoxyaminal moiety was successfully achieved to obtain γ-methoxylactams (myceliothermophins C and D). Subsequent hydrolysis of these compounds afforded the corresponding γ-hydroxylactam, and myceliothermophins A and B in high yield. Myceliothermophin E was also synthesized by dehydration of the obtained γ-hydroxylactams. The absolute configurations of myceliothermophins A-E were also successfully determined. 相似文献
9.
T. Umecky T. Takamuku T. Aida T. Makino T. Aizawa M. Kanakubo 《Journal of solution chemistry》2014,43(9-10):1539-1549
2H and 17O NMR relaxation times, T 1(2H) and T 1(17O), and 2H NMR chemical shifts, δ(2H), in CO2-saturated CD3OD and C2D5OD solutions were measured at 313.2 K over the pressure range up to ~6 MPa. The rotational correlation times, τ r, of the CD and OD axes within CD3OD and C2D5OD molecules and the CO axis within the CO2 molecule were determined from T 1(2H) and T 1(17O), and the magnetic susceptibility-corrected chemical shifts, δ corr, were derived from δ(2H). The differences in τ r and δ corr observed between the two alcohol systems: τ r and δ corr of OD in C2D5OD, decreased rapidly with increasing CO2 concentration, while those of OD in CD3OD remained almost unchanged at mole fractions of CO2, \( x_{\text CO_{2}} \) , lower than ~0.25 and then slightly decreased at higher \( x_{\text CO_{2}} \) . The hydrogen bonding structure in C2D5OD was found to be gradually broken down by CO2 dissolution. On the other hand, in CD3OD, it has been revealed that the hydrogen bonding structure can persist at \( x_{\text CO_{2}} \) < ~0.25 but then collapses at higher \( x_{\text CO_{2}} \) . 相似文献
10.
Takashi Nakamura Keiji Yashiro Kazuhisa Sato Junichiro Mizusaki 《Journal of solid state chemistry》2009,182(5):1121-299
In order to elucidate the relation between thermodynamic quantities, the defect structure, and the defect equilibrium in La2−xSrxNiO4+δ, statistical thermodynamic calculation is carried out and calculated results are compared to those obtained from experimental data. Partial molar enthalpy of oxygen and partial molar entropy of oxygen are obtained from δ-P(O2)-T relation by using Gibbs-Helmholtz equation. Statistical thermodynamic model is derived from defect equilibrium models proposed before by authors, localized electron model and delocalized electron model which could well explain the variation of oxygen content of La2−xSrxNiO4+δ. Although assumed defect species and their equilibrium are different, the results of thermodynamic calculation by localized electron model and delocalized electron model show minor difference. Calculated results by the both models agree with the thermodynamic quantities obtained from oxygen nonstoichiometry of La2−xSrxNiO4+δ. 相似文献