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141.
Proton magnetic resonance spectra were measured at 1·8 K for the compounds NH4Br, NH4I, NH4SCN, (NH4)2CrO4, and NH4NO3. The observed derivative curves cannot be explained on the basis only of the dipolar interactions between protons in the NH4 + ion held rigidly in the crystal lattices. We considered the effect of quantum mechanical tunnelling on the rotation of an NH4 + ion about its C3-axis and calculated the theoretical lineshapes for various assumed values of the tunnelling splitting constants. Comparison between experiment and theory is quite satisfactory, and the tunnelling splitting constants, Δ, in the librational ground state of the ammonium ion in these salts are determined. It is found that there is a linear relation between the Δ values and the potential barrier to reorientation. 相似文献
142.
143.
A survey of metabolic changes in potato leaves by NMR‐based metabolic profiling in relation to resistance to late blight disease under field conditions
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Satoru Tomita Seishi Ikeda Shogo Tsuda Nobutaka Someya Kenji Asano Jun Kikuchi Eisuke Chikayama Hiroshi Ono Yasuyo Sekiyama 《Magnetic resonance in chemistry : MRC》2017,55(2):120-127
Non‐targeted nuclear magnetic resonance (NMR)‐based metabolic profiling was applied to potato leaves to survey metabolic changes associated with late blight resistance under field conditions. Potato plants were grown in an experimental field, and the compound leaves with no visible symptoms were collected from 20 cultivars/lines at two sampling time points: (i) the time of initial presentation of symptoms in susceptible cultivars and (ii) 12 days before this initiation. 1H NMR spectra of the foliar metabolites soluble in deuterium oxide‐ or methanol‐d4‐based buffers were measured and used for multivariate analysis. Principal component analysis for six cultivars at symptom initiation showed a class separation corresponding to their levels of late blight resistance. This separation was primarily explained by higher levels of malic acid, methanol, and rutin and a lower level of sucrose in the resistant cultivars than in the susceptible ones. Partial least squares regression revealed that the levels of these metabolites were strongly associated with the disease severity measured in this study under field conditions. These associations were observed only for the leaves harvested at the symptom initiation stage, but not for those collected 12 days beforehand. Subsequently, a simple, alternative enzymatic assay for l ‐malic acid was used to estimate late blight resistance, as a model for applying the potential metabolic marker obtained. This study demonstrated the potential of metabolomics for field‐grown plants in combination with targeted methods for quantifying marker levels, moving towards marker‐assisted screening of new cultivars with durable late blight resistance. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
144.
Synthesis of a Pentacene‐Type Silaborin via Double Dehydrogenative Cyclization of 1,4‐Diboryl‐2,5‐disilylbenzene
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Tatsuya Hirofuji Dr. Toshiaki Ikeda Prof. Dr. Takeharu Haino Prof. Dr. Yohsuke Yamamoto Prof. Dr. Atsushi Kawachi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(28):9734-9739
A new pentacene‐type silaborin, in which three benzene rings are bridged by silicon and boron atoms, has been synthesized and characterized by using NMR spectroscopy and X‐ray crystallographic analysis. The precursor, 1,4‐bis(dimesitylboryl)‐2,5‐bis(phenylsilyl)benzene ( 4 ), was prepared by stepwise introduction of a silyl group and a boryl group to a benzene ring starting from 1,4‐dibromobenzene. Double cyclization of 4 proceeds by a H‐Mes exchange and a B‐H/C‐H dehydrogenative condensation to afford pentacene‐type silaborin 5 . X‐ray crystal structure analysis reveals that 5 adopts a bent structure rather than a planar one. UV/Vis spectra and DFT calculations for 5 reveal a lowering of the LUMO energy level compared with corresponding anthracene‐type 3 . 相似文献
145.
Ayabe M Ikeda A Shinkai S Sakamoto S Yamaguchi K 《Chemical communications (Cambridge, England)》2002,(10):1032-1033
Porphyrin dimer 1, which does not have an inside cavity and cannot interact with [60]fullerene (C60), becomes an excellent C60-acceptor with a large cavity in the presence of a Pd(II) complex. 相似文献
146.
Kaneda M Asaoka S Ikeda H Mori T Wada T Inoue Y 《Chemical communications (Cambridge, England)》2002,(12):1272-1273
A hydrostatic pressure of up to 750 MPa induced discontinuous changes in the enantiomeric excess of the (E)-isomer obtained in the enantio-differentiating photoisomerization of (Z)-cyclooctene and (Z,Z)-cycloocta-1,5-diene, sensitized by chiral benzene-1,2,4,5-tetracarboxylates; indicating a switching of the enantio-differentiation mechanism, which is attributable to dramatic conformational changes of chiral alkoxycarbonyl auxiliaries at a specific pressure. 相似文献
147.
Naito O Cui Z Ide S Suzuki T Oikawa T Seki M Hatae T Fujita T Kondoh T Shirai H Ikeda Y Ushigusa K 《Physical review letters》2002,89(6):065001
Evolution of the lower-hybrid(LH)-driven current profile was measured during the formation of an internal transport barrier (ITB) in a reversed magnetic shear discharge. As the ITB developed, the initially centrally peaked LH-driven current profile gradually turned hollow and was sometimes accompanied by an off-axis peak in the electron temperature profile. These observations indicate the concentration of LH power deposition to the ITB for this case as a result of nonlinear coupling between the LH waves and the target plasma. 相似文献
148.
Hashi K Shimizu T Goto A Kiyoshi T Matsumoto S Wada H Fujito T Hasegawa K Yoshikawa M Miki T Ito S Hamada M Hayashi S 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2002,156(2):318-321
We have developed a 920-MHz NMR system and performed the proton NMR measurement of H(2)O and ethylbenzene using the superconducting magnet operating at 21.6 T (920 MHz for proton), which is the highest field produced by a superconducting NMR magnet in the persistent mode. From the NMR measurements, it is verified that both homogeneity and stability of the magnet have a specification sufficient for a high resolution NMR. 相似文献
149.
Kaoru Ikeda 《Communications in Mathematical Physics》1996,180(3):757-777
We consider constructing the higher order Hamiltonian structures on the dual of the Lie algebra from the first Hamiltonian structure of the coadjoint orbit method. For this purpose we show that the structure of the Lie algebrag is inherited to the algebra of vector fields ong
* through the solution of the Modified Classical Yang-Baxter equation (Classicalr matrix). We study the algebra that generates the compatible Poisson brackets.This work was supported by Grant Aid for Scientific Research, the Ministry of Education. 相似文献
150.
Visible photoluminescence (PL) of nanocrystalline silicon (nc-Si) embedded in single crystal CaF2 formed on Si(1 1 1) has been studied and the influence of ex situ rapid thermal annealing (RTA) on the surface morphology and PL spectra has been studied. It has been found that the PL intensity and uniformity was improved by RTA with appropriate temperature and short annealing time. 相似文献