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41.
E. Beckmann Richard Meyer K. Desamari J. Thiele K. Haring R. Hanslian J. v. Bosse A. Stock G. Krüss E. Thiele O. Liesche F. Junker E. Rimini F. Olivari L. Rügheimer E. Rudolfi L. Gonder D. Mc. Intosh E. H. Archibald und W. Weber 《Fresenius' Journal of Analytical Chemistry》1912,51(9):562-570
Ohne Zusammenfassung 相似文献
42.
Stone M Stock G Bunin K Kumar K Epstein M Kambhamettu C Li M Parthasarathy V Prince J 《The Journal of the Acoustical Society of America》2007,122(1):532-541
Speech is usually produced in an upright sitting or standing posture. Measurements and judgments of speech may be made in conditions requiring a supine position, however. These conditions include MRI recordings, and oral procedures, such as, adjustments to dental appliances, medical and surgical procedures. It is of interest, therefore, to see whether gravity has strong or systematic effects on tongue behavior. In the present study, 13 subjects repeated several words, which contained extreme consonant and vowel tongue positions, during upright and supine condition. Ultrasound imaging provided midsagittal tongue contours, in each condition, for comparison. A neck brace was used to stabilize transducer placement and the palate was used as a physiological reference to register the data sets. Results showed a significant subject effect. In supine position the tongue was more posterior than upright for seven subjects, more anterior for two subjects and varied by phoneme for four subjects. However, there was no significant phoneme effect. The direction of change and the amount of change were not directly related. Most subjects had small upright-supine differences. The largest differences, less than 3 mm on average, were in the posterior tongue. 相似文献
43.
Classical molecular dynamics simulations of the folding of alanine peptides in aqueous solution are analyzed by constructing a deterministic model of the dynamics, using methods from nonlinear time series analysis. While the dimension of the free energy landscape increases with system size, a Lyapunov analysis shows that the effective dimension of the dynamic system is rather small and even decreases with chain length. The observed reduction of phase space is a nonlinear cooperative effect that is caused by intramolecular hydrogen bonds that stabilize the secondary structure of the peptides. 相似文献
44.
Brandon Wilfong Muhtar Ahart Stephen A. Gramsch Chris Stock Xiaomin Li H. Luo Russell J. Hemley 《Journal of Raman spectroscopy : JRS》2016,47(2):227-232
The vibrational and structural properties of Pb(Fe0.5Nb0.5)O3 have been investigated using Raman spectroscopy up to 40 GPa at 300 K and from 300 to 415 K at selected pressures. The measurements reveal three phase transitions, at 5.5, 8.7, and 24 GPa at room temperature. The temperature dependences of the spectra indicate transitions at 1.5 GPa, at 335 and 365 K. The results are consistent with the appearance of an intermediate tetragonal P4mm phase between the ferroelectric R3m and paraelectric Pm‐3m phases. A P–T phase diagram is proposed that allows further insight into the magnetoelectric coupling present in this material. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
45.
Philipp Stock Nicole Spintig Juliane Scholz Jan Dirk Epping Christian Oelsner Dennis Wiedemann 《Journal of Coordination Chemistry》2015,68(17-18):3099-3115
This work presents a detailed study of the photo-induced spin-state dynamics of the photochromic iron(II) complex 1, where the metal ion is in the field of a tripodal hexa-imine ligand with protolysable phenol groups. The nature of the complex’s ground state has been identified as a spin singlet by 1H NMR and steady-state UV/vis spectroscopies, and its distorted octahedral structure was analyzed via crystal structure determination. Sub-picosecond and nanosecond time-resolved laser flash photolysis experiments identify the long-lived quintet state of 1 as the selective product of photoexcitation in the UV/vis spectral region. Thermal barriers of spin-state interconversion as a function of solvent and added base are derived from temperature-dependent rates of transient decay. Ground-state recovery is found to be significantly affected by the solvent and is strongly enhanced, in particular, by base-driven solvolysis of the ligand’s phenol groups. Partial spontaneous deprotonation of the phenolic hydroxyl groups of 1 seems to prevail on metal oxide surfaces, i.e. on alumina. Composite materials, like 1 at Al2O3, that retain the characteristic spectral features of the parent iron(II) complex can be readily obtained by wet impregnation of hydrous alumina with solutions of 1. 相似文献
46.
The bifunctional metalloligand bis(carboxyethylgermanium)sesquioxide, (HOOCCH2CH2Ge)2O3, was employed in the systematic high‐throughput (HT) investigation of the system Zn2+/(HOOCCH2CH2Ge)2O3/H2O/C4H9OH. Two new metal‐organogermanates Zn[(OOCCH2CH2Ge)2O3] ( 1 ) and Zn2(O3GeCH2CH2COO) ( 2 ) were discovered that show two new structural motifs for this class of compounds. Whereas in compound 1 a formal intercalation in the structure of (HOOCCH2CH2Ge)2O3 is observed, 2 exhibits a new layered structure composed of CGeO3 and ZnO4 unit linked by μ3‐oxygen atoms. Both connectivity modes lead to dense three‐dimensional framework structures. 相似文献
47.
Horcajada P Salles F Wuttke S Devic T Heurtaux D Maurin G Vimont A Daturi M David O Magnier E Stock N Filinchuk Y Popov D Riekel C Férey G Serre C 《Journal of the American Chemical Society》2011,133(44):17839-17847
A series of organically modified iron(III) terephthalate MIL-88B and iron(III) 4,4'-biphenyl dicarboxylate MIL-88D flexible solids have been synthesized and characterized through a combination of X-ray diffraction, IR spectroscopy, and thermal analysis (MIL stands for Material from Institut Lavoisier). The swelling amplitude of the highly flexible MOFs tuned by introducing functional groups onto the phenyl rings shows a clear dependence on the steric hindrance and on the number of groups per aromatic ring. For instance, while the introduction of four methyl groups per spacer in dried MIL-88B results in a large permanent porosity, introducing two or four methyl groups in MIL-88D allows an easier pore opening in the presence of liquids without drastically decreasing the swelling magnitude. The influence of the degree of saturation of the metal center and the nature of the solvent on the swelling is also discussed. Finally, a computationally assisted structure determination has led to a proposal of plausible structures for the closed (dried) and open forms of modified MIL-88B and MIL-88D and to evaluation of their framework energies subject to the nature of the functional groups. 相似文献
48.
Reinhard Stock 《Pramana》2003,60(5):965-982
I review recent progress in ultrarelativistic nucleus-nucleus collisions, and the connection of this field to modern QCD theory
of deconfinement and/or chiral symmetry restoration. The talks at this Conference have shown a convergence of data and theory
as far as the CERN SPS investigations at √s = 17 GeV are concerned; the parton-hadron phase boundary seems now located atT = 170 ± 10 MeV. New data from RHIC and direct photon production results from CERN have been shown that point out the field’s
future direction: analysis of partonic matter atT > 200 MeV. Astrophysics analysis was shown to be linked crucially to further theoretical progress with non-perturbative QCD. 相似文献
49.
Properties of solutions and colloidal suspensions such as molecular and particle dynamics, diffusivities, and size distributions may be determined through dynamic light-scattering experiments. Here a number of methods for predicting the details of the linewidth distribution from photon correlation spectroscopy data are reviewed. Their performance on simulated data (with and without noise added) and experimental data from polystyrene latex standards (including a mixture of two standards) is compared. Methods which do not assume a specific form for the distribution are considered. These include cumulants, histograms, exponential sampling, subdistributions, a non-negatively constrained histogram, and Provencher's constrained regularization. Constrained regularization was found to be most robust to noise present in the autocorrelation function and therefore most reliable for analyzing experimental data; however, the method sometimes oversmoothed the distribution. For bimodal distributions the histogram method performed well in our testing, especially when the approximate peak locations were known a priori. Two linear least-squares fitting methods, exponential sampling and the non-negatively constrained histogram, yield accurate values for the overall mean and standard deviation and can be implemented easily on a microcomputer. The linear subdistribution method, although computationally fast, sometimes was not as accurate as other methods. 相似文献
50.