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排序方式: 共有214条查询结果,搜索用时 15 毫秒
41.
water proton T1 in blood from healthy volunteers and patients with acute leukaemia, lymphoma; iron deficiency anaemia, post hepatitic cirrhosis and tuberculosis, was measured by a FT-NMR spectrometer. Relaxation measurements were performed at 60MHz frequency and a temperature of (20 ± 0.5)C. The T1 measured for each disease correlates strongly with hemoglobin content. The spin-lattice relaxation time in each abnormal group was signaficantly (p < 0.001) elevated over normal group. There is little overlap between the healthy and abnormal groups. On the contrast, T1 ranges obtained for malignant groups and non-malignant diseases do overlap. 相似文献
42.
Max-Olivier Hongler Halil Mete Soner Ludwig Streit 《Applied Mathematics and Optimization》2004,49(2):113-121
We construct the explicit connection existing between a solvable model of the discrete velocities non-linear Boltzmann equation and the Hamilton-Bellman-Jacobi equation associated with a simple optimal control of a piecewise deterministic process. This study extends the known relation that exists between the Burgers equation and a simple controlled diffusion problem. In both cases the resulting partial differential equations can be linearized via a logarithmic transformation and hence offer the possibility to solve physically relevant non-linear field models in full generality. 相似文献
43.
M. Sc. Ibrahim Halil Öner M. Sc. Christine Joy Querebillo Dr. Christin David Dipl.‐Ing. Ulrich Gernert M. Sc. Carsten Walter Prof. Dr. Matthias Driess Prof. Dr. Silke Leimkühler Dr. Khoa Hoang Ly Prof. Dr. Inez M. Weidinger 《Angewandte Chemie (International ed. in English)》2018,57(24):7225-7229
We present the fabrication of TiO2 nanotube electrodes with high biocompatibility and extraordinary spectroscopic properties. Intense surface‐enhanced resonance Raman signals of the heme unit of the redox enzyme Cytochrome b5 were observed upon covalent immobilization of the protein matrix on the TiO2 surface, revealing overall preserved structural integrity and redox behavior. The enhancement factor could be rationally controlled by varying the electrode annealing temperature, reaching a record maximum value of over 70 at 475 °C. For the first time, such high values are reported for non‐directly surface‐interacting probes, for which the involvement of charge‐transfer processes in signal amplification can be excluded. The origin of the surface enhancement is exclusively attributed to enhanced localized electric fields resulting from the specific optical properties of the nanotubular geometry of the electrode. 相似文献
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45.
sa Sdr Yadigar Gülseven Sdr Sndor Gbi Halil Berber Rui Fausto 《Molecules (Basel, Switzerland)》2021,26(9)
A new Schiff base compound, 3-(5-bromo-2-hydroxybenzylideneamino)phenol (abbreviated as BHAP) was synthesized and characterized by 1H- and 13C- nuclear magnetic resonance and infrared spectroscopies. DFT/B3LYP/6-311++G(d,p) calculations were undertaken in order to explore the conformational space of both the E- and Z- geometrical isomers of the enol-imine and keto-amine tautomers of the compound. Optimized geometries and relative energies were obtained, and it was shown that the most stable species is the E-enol-imine form, which may exist in four low-energy intramolecularly hydrogen-bonded forms (I, II, V, and VI) that are almost isoenergetic. These conformers were concluded to exist in the gas phase equilibrium with nearly equal populations. On the other hand, the infrared spectra of the compound isolated in a cryogenic argon matrix (10 K) are compatible with the presence in the matrix of only two of these conformers (conformers II and V), while conformers I and VI convert to these ones by quantum mechanical tunneling through the barrier associated with the rotation of the OH phenolic group around the C–O bond. The matrix isolation infrared spectrum was then assigned and interpreted with help of the DFT(B3LYP)/6-311++G(d,p) calculated infrared spectra for conformers II and V. In addition, natural bond orbital (NBO) analysis was performed on the most stable conformer of the experimentally relevant isomeric form (E-enol-imino conformer V) to shed light on details of its electronic structure. This investigation stresses the fundamental structural relevance of the O–H···N intramolecular H-bond in o-hydroxyaryl Schiff base compounds. 相似文献
46.
This paper is concerned with a generalization of Bernstein–Bézier curves. A one parameter family of rational Bernstein–Bézier
curves is introduced based on a de Casteljau type algorithm. A subdivision procedure is discussed, and matrix representation
and degree elevation formulas are obtained. We also represent conic sections using rational q-Bernstein–Bézier curves.
AMS subject classification (2000) 65D17 相似文献
47.
Improvement of cycling stability of LiMn2O4 cathode by Fe2O3 surface modification for Li-ion battery
The surface of spinel LiMn2O4 was modified with Fe2O3 (1.0, 2.0, 3.0, 4.0, and 5.0 wt%) by a simple sol-gel method to improve its electrochemical performance at room temperature. Compared with bare LiMn2O4, surface modification improved cycling stability of the material. Among the surface-modified cathode materials, the 3.0- and 4.0-wt% surface-modified cathodes have lesser capacity loss than the others. While the bare LiMn2O4 showed 25.4 % capacity loss in 70 cycles at room temperature, 3.0 and 4.0 wt% of Fe2O3-modified LiMn2O4 only exhibited the capacity loss of 2.6 and 2.3 % in 70 cycles at room temperature, respectively. The structure and phase were identified with X-ray diffractometer along with the lattice constant calculated by a Win-Metric program. 相似文献
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Bayraktar H Ghosh PS Rotello VM Knapp MJ 《Chemical communications (Cambridge, England)》2006,(13):1390-1392
Functionalized gold nanoparticles bind selectively to cytochrome c or cytochrome c peroxidase and inhibit enzyme turnover. 相似文献