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941.
Seto Kenji Hollenshead Jeromy T. Watson A. Ted Chang C. T. Philip Slattery John C. 《Transport in Porous Media》2001,42(3):351-387
This study develops a methodology for determining the absolute permeability distribution in a porous media sample using velocity data obtained from NMR imaging experiments. An objective function describing the discrepancy between observed and simulated data is reduced by iteratively updating the permeability. This parameter estimation scheme is based on an iterative method which uses optimal control theory to refine the estimates. Although this theory is developed for both isotropic and anisotropic porous media, the permeability reconstructions examined in this paper are restricted to the isotropic case. Synthetic data are used to investigate the impact of varying the noise in the experimental data, the degree of parameterization, the relative weighting of the regularization term in the objective function, and the amount and type of data required to obtain a satisfactory permeability reconstruction. These synthetic data are extracted from the solution of numerical experiments that have utilized an assumed permeability distribution. The methodology is also applied to data gathered in laboratory experiments for water flow in a sandstone sample. 相似文献
942.
Kenji Sasaki Ying‐Xue Zhang Kensuke Okuda Takashi Hirota 《Journal of heterocyclic chemistry》2001,38(2):425-429
The reactions of N‐(5,6‐dihydro[1]benzoxepino[5,4‐ d]pyrimidin‐4‐yl)amidines or its amide oxime derivatives with hydroxylamine hydrochloride gave abnormal cyclization products via a ring cleavage of pyrimidine component accompanied with a ring closure of [1,2,4]oxadiazole. 相似文献
943.
Hiroshi Maruoka Kenji Yamagata Motoyoshi Yamazaki 《Journal of heterocyclic chemistry》2001,38(1):269-274
The reactions of 2‐benzamido‐4,5‐dihydro‐3‐thiophene(and ‐3‐furan)carbonitriles ( 1a‐c and 4a‐c ) with ethyl acetoacetate in the presence of tin(IV) chloride and triethylamine provided the corresponding ethyl 2‐(5,6‐dihydro‐2‐phenylthieno(and furo)[2,3‐d]pyrimidin‐4‐yl)‐3‐oxobutanoates ( 2a‐c and 9a‐c ). Similarly, compounds 1a‐c and 4a‐c reacted with dialkyl malonates to give the corresponding dialkyl(5,6‐dihydro‐2‐phenylthieno(and furo)[2,3‐d]pyrimidin‐4‐yl)propanedioates ( 5a‐c, 6a‐c, 10a‐c and 11a‐c ). 相似文献
944.
Kiyofumi Kurihara Takao Iguchi Toshiaki Banaka Kenji Ochi Kazuo Kojima 《Fluid Phase Equilibria》2001,180(1-2):59-69
The excess molar enthalpies of the systems 2-butanone+water and methanol+hexane which show limited miscibility were measured at 283.15–298.15 K using a flow microcalorimeter. The experimental data were correlated using three local-composition (LC) models (NRTL, modified Wilson and modified EBLCM). These models were also used to predict the liquid–liquid equilibria for both systems with the parameters obtained from the excess enthalpy data. 相似文献
945.
We prove a smoothing property for one dimensional time dependent Schr?dinger equations with potentials which satisfy at infinity, k≥ 2. As an application, we show that the initial value problem for certain nonlinear Schr?dinger equations with such potentials
is L
2 well-posed. We also prove a sharp asymptotic estimate of the L
p
-norm of the normalized eigenfunctions of H=−Δ+V for large energy.
Dedicated to Jean-Michel Combes on the occasion of his Sixtieth Birthday
Received: 10 October 2000 / Accepted: 29 March 2001 相似文献
946.
A solid state ionic device to titrate electrolytes in water was produced, and the performance of the device was examined. The device named the coulometric titration apparatus is a three-component electrochemical cell like an electrodialyzer. The central component, the analyzing room, is a container of the sample solution. The sample solution, 10−1 M H2SO4, NaOH, Na2SO4, or 10−7–10−2 M Na2SO4, is separated from the cathode and the anode room solutions, 10−2 M H2SO4, NaOH, or Na2SO4, by Nafion-117 and Tosflex IE-SF34 membranes working as the anion and the cation blocking electrodes, respectively. The quantity of electricity to extract whole electrolytes in the sample solution is evaluated from the peak area of the titration curve. The sample concentration is successfully determined by the calibration curve method, with the quantity of electricity and the sample volume (6 ml) in the range from 10−1 to 10−5 M. 相似文献
947.
Kenji Nishihara 《数学进展》2001,(4)
本文讨论单个粘性守恒律方程与具有粘性的p方程组的Cauchy问题.根据初始资料的不同情形,其相应的Riemann问题以疏散波,激波或它们的迭加为弱解.本文的目的是指出Cauchy问题的解将分别趋于疏散波,激波或它们的迭加.本文基本方法是能量积分法.文中综述了现有的成果,也提出了一些未解决的问题. 相似文献
948.
Tamiko Takahashi Hiroaki Kameda Tomoyo Kamei Jyunichi Koyanagi Fabio Pichierri Kenji Omata Miyuki Ishizaki Hiroshi Nakamura 《Tetrahedron: Asymmetry》2013,24(17):1001-1009
Optically active 1-fluoroindan-1-carboxylic acid (FICA) was designed and prepared as its methyl ester for determining the absolute configuration of chiral molecules by both 1H and 19F NMR spectroscopies. Enantiomerically pure isomers of FICA methyl esters (FICA Me esters) were obtained by chromatographic separation using HPLC with a Daicel Chiralcel OJ-H column. The absolute configuration of the (+)-FICA Me ester was deduced to be (S) by X-ray crystallographic analysis of the (+)-FICA amide of (R)-α-phenethylamine. Both enantiomers were derived to the diastereomeric esters of chiral secondary alcohols by an ester exchange reaction. In the 1H NMR spectra, the signs of ΔδH (δR ? δS) were consistent on each side of the FICA molecular plane. Therefore, the concept of the modified Mosher’s method could be successfully applied to the FICA-based procedure. Moreover, the consistency in the signs of ΔδF (δR ? δS) values suggests that the FICA method would be reliable in assigning the absolute configurations of secondary alcohols based on 19F NMR spectroscopy. 相似文献
949.
Dr. Tomohiro Higashino Keiichi Ishida Dr. Tsuneaki Sakurai Prof. Dr. Shu Seki Tatsuki Konishi Dr. Kenji Kamada Prof. Dr. Kenji Kamada Prof. Dr. Hiroshi Imahori 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(25):6425-6438
Linear ladder-type π-conjugated molecules have attracted much interest because of their intriguing physicochemical properties. To modulate their electronic structures, an effective strategy is to incorporate main-group elements into ladder-type π-conjugated molecules. In line with this strategy, a variety of ladder-type π-conjugated molecules with main-group elements have been synthesized to explore their potential utility as organic functional materials. In this context, phosphole-based π-conjugated molecules are highly attractive, owing to their unique optical and electrochemical properties, which arise from the phosphorus atom. Herein, the synthesis and physicochemical properties of doubly thiophene-fused benzodiphospholes, as a new class of phosphole-based ladder-type π-conjugated molecule, are reported. Systematic investigations into the physicochemical properties of doubly thiophene-fused benzodiphospholes revealed their pluripotent features: intense near-infrared fluorescence, excellent two-photon absorption property, and remarkably high electron-transporting ability. This study demonstrates the potential utility of doubly thiophene-fused benzodiphospholes as organic functional materials for biological imaging, nonlinear optics, organic transistors, and organic photovoltaics. 相似文献
950.