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101.
Shin-ichi Takekuma Manami Yamamoto Aki Nakagawa Tomohiro Iwata Toshie Minematsu Hideko Takekuma 《Tetrahedron》2012,68(39):8318-8329
Wittig reaction of (E)-3-(3-guaiazulenyl)propenal (11) with (3-guaiazulenylmethyl)triphenylphosphonium bromide (9) in ethanol containing NaOEt at 25 °C for 24 h under argon gives the title new (2E,4E)-1,3-butadiene derivative 4, in 33% isolated yield, which upon treatment with hexafluorophosphoric acid (i.e., 65% HPF6 aqueous solution) in tetrahydrofuran (=THF) at 25 °C for 1 h under aerobic conditions affords a new air (two-electron) oxidation product (E)-ethylene-1,2-bis(3-guaiazulenylmethylium) bis(hexafluorophosphate) (14), quantitatively, and further, zinc-reduction of 14 in trifluoroacetic acid (=CF3COOH) at 0 °C for 1 h under argon reverts 4, quantitatively. Along with the above interesting results, our discovered another preparation method, spectroscopic properties, crystal structure, and electrochemical behavior of 4, which serves as a strong two-electron donor and acceptor, compared with those of the previously reported (E)-1,2-di(3-guaiazulenyl)ethylene (3) are documented in detail. 相似文献
102.
We extend recent work on nonlinear optimal control problems with integer restrictions on some of the control functions (mixed-integer optimal control problems, MIOCP). We improve a theorem (Sager et?al. in Math Program 118(1): 109–149, 2009) that states that the solution of a relaxed and convexified problem can be approximated with arbitrary precision by a solution fulfilling the integer requirements. Unlike in previous publications the new proof avoids the usage of the Krein-Milman theorem, which is undesirable as it only states the existence of a solution that may switch infinitely often. We present a constructive way to obtain an integer solution with a guaranteed bound on the performance loss in polynomial time. We prove that this bound depends linearly on the control discretization grid. A numerical benchmark example illustrates the procedure. As a byproduct, we obtain an estimate of the Hausdorff distance between reachable sets. We improve the approximation order to linear grid size h instead of the previously known result with order ${\sqrt{h}}$ (H?ckl in Reachable sets, control sets and their computation, augsburger mathematisch-naturwissenschaftliche schriften. Dr. Bernd Wi?ner, Augsburg, 1996). We are able to include a Special Ordered Set condition which will allow for a transfer of the results to a more general, multi-dimensional and nonlinear case compared to the Theorems in Pietrus and Veliov in (Syst Control Lett 58:395–399, 2009). 相似文献
103.
M. Sakaguchi T. OhuraT. Iwata Y. Enomoto-Rogers 《Polymer Degradation and Stability》2012,97(3):257-263
Nano cellulose particles covered with a block copolymer of microcrystalline cellulose and poly(methyl methacrylate) (MCC-block-PMMA) were produced by a solid mechano-chemical polymerization. The polymerization of methyl methacrylate was initiated by chain-end-type microcrystalline cellulose (MCC) radicals (i.e., MCC mechano radicals) on the surface of MCC that were induced by mechanical fracture of β-1,4 glycosidic linkages. The chemically modified cellulose particles with MCC-block-PMMA were fractionated by Soxhlet extraction with chloroform, and resulted in MCC-block-PMMA residue from residue on the filter and MCC-block-PMMA filtrate from filtrate solution. The surface of the MCC particles chemically modified with MCC-block-PMMA in MCC-block-PMMA residue was partially covered with PMMA chains of the MCC-block-PMMA. In contrast, the surfaces of the MCC nanoparticles chemically modified with MCC-block-PMMA in MCC-block-PMMA filtrate were fully covered with PMMA chains of the MCC-block-PMMA. A dispersion of the chemically fully modified MCC nanoparticles in chloroform was optically transparent. The average diameter of the chemically fully modified MCC nanoparticles in chloroform was estimated to be 52 nm. These were confirmed by electron spin resonance, Fourier transform infrared, and 1H nuclear magnetic resonance spectroscopy, by gel permeation chromatography and dynamic light scattering. 相似文献
104.
Yoshimi Ohmae Natsuko I. Kobayashi Keitaro Tanoi Atsushi Hirose Takayuki Saito Akihiko Noda Naoko Iwata Akimasa Nakano Satoru Nakamura Tomoko M. Nakanishi 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(1):241-244
The mineral composition of frozen food of taro [Colocasia esculenta (L.) Schott] was analyzed to categorize the geographical production place of taro. The concentrations of Co and H2PO4
− were found to be useful to separate the producing place between Japan and China. The analysis was performed by instrumental
neutron activation analysis (INAA) and ion chromatography (IC). In the case of INAA, the samples were dried and sealed in
a vinyl bag and irradiated with thermal neutrons from JRR3M, installed at Japan Atomic Energy Agency (JAEA). The activated
samples were cooled down for a few weeks and the elements (Co, Cr, Fe, Rb, Zn) were determined. Cobalt concentration of frozen
taro from China was higher than that from Japan. The tendency was the same in the fresh sample of taro. When concentration
of H2PO4
− of frozen sample was measured, taro from Japanese product was higher than that of Chinese one, contrary to fresh sample.
This result might be caused by the leakage of H2PO4
− during freezing process, indicating that we should be careful to apply the discrimination indicators. In addition to Co,
there was a significant difference of Rb and Fe concentrations between frozen taro from Japan and China. 相似文献
105.
Yoshida K Iwata K Nishiyama Y Kimura Y Hamaguchi HO 《The Journal of chemical physics》2012,136(10):104504
Vibrational cooling rate of the first excited singlet (S(1)) state of trans-stilbene and bulk thermal diffusivity are measured for seven room temperature ionic liquids, C(2)mimTf(2)N, C(4)mimTf(2)N, C(4)mimPF(6), C(5)mimTf(2)N, C(6)mimTf(2)N, C(8)mimTf(2)N, and bmpyTf(2)N. Vibrational cooling rate measured with picosecond time-resolved Raman spectroscopy reflects solute-solvent and solvent-solvent energy transfer in a microscopic solvent environment. Thermal diffusivity measured with the transient grating method indicates macroscopic heat conduction capability. Vibrational cooling rate of S(1) trans-stilbene is known to have a good correlation with bulk thermal diffusivity in ordinary molecular liquids. In the seven ionic liquids studied, however, vibrational cooling rate shows no correlation with thermal diffusivity; the observed rates are similar (0.082 to 0.12 ps(-1) in the seven ionic liquids and 0.08 to 0.14 ps(-1) in molecular liquids) despite large differences in thermal diffusivity (5.4-7.5 × 10(-8) m(2) s(-1) in ionic liquids and 8.0-10 × 10(-8) m(2) s(-1) in molecular liquids). This finding is consistent with our working hypothesis that there are local structures characteristically formed in ionic liquids. Vibrational cooling rate is determined by energy transfer among solvent ions in a local structure, while macroscopic thermal diffusion is controlled by heat transfer over boundaries of local structures. By using "local" thermal diffusivity, we are able to simulate the vibrational cooling kinetics observed in ionic liquids with a model assuming thermal diffusion in continuous media. The lower limit of the size of local structure is estimated with vibrational cooling process observed with and without the excess energy. A quantitative discussion with a numerical simulation shows that the diameter of local structure is larger than 10 nm. If we combine this lower limit, 10 nm, with the upper limit, 100 nm, which is estimated from the transparency (no light scattering) of ionic liquids, an order of magnitude estimate of local structure is obtained as 10 nm < L < 100 nm, where L is the length or the diameter of the domain of local structure. 相似文献
106.
In this paper, we establish a stronger version of Artemov's arithmetical completeness theorem of the Logic of Proofs . Moreover, we prove a version of the uniform arithmetical completeness theorem of . 相似文献
107.
Dr. Takayuki Iwata Mizuki Hyodo Takuto Fukami Prof. Dr. Yoshihito Shiota Prof. Dr. Kazunari Yoshizawa Prof. Dr. Mitsuru Shindo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(39):8506-8510
We report herein an efficient method to synthesize triptycenes by the reaction of benzynes and anthranoxides, which are electron-rich and readily prepared from the corresponding anthrones. Using this method, 1,9-syn-substituted triptycenes were regioselectively obtained employing 3-methoxybenzynes. This method was also applied to synthesize pentiptycenes. A DFT study revealed that the cycloaddition of lithium anthranoxide and benzyne proceeds stepwise. 相似文献
108.
109.
110.
Yoshinori Shiobara Tomoko Iwata Mitsuaki Kodama Yoshinori Asakawa Tsunematsu Takemoto Yoshimasa Fukazawa 《Tetrahedron letters》1985,26(7):913-916
Dehydrocurdione, a sesquiterpene isolated from , was converted to curcumenol, isocurcumenol or new spirolactones in a highly selective manner and their absolute configurations were determined. 相似文献