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21.
Magnetic susceptibility measurements were used to study solid solutions Ti3?xCrxO5 (0 ? × ? 0.17). Contributions to magnetic susceptibility for the α-phase were defined by the statistical analysis of the experimental data. A conclusion was made on the varing character of exchange interactions in α-Ti3?xCrxO5 with increasing Cr content. In the present work, the information given indicates that Cr stabilizes the high-temperature α-Ti3O5 and decreases the temperature of semiconductor-metal phase transition. Magnetic properties of low-temperature α-Ti3O5 phase with chromium addition are shown to be explained by the existence of exchange-coupled pairs Ti3+? Cr3+. 相似文献
22.
Summary The seasonal variations of the carbon content in the ocean are shown to be small as compared to those taking place in the
atmosphere. Atmospheric meridional mixing is not intense enough to compensate for the variations of the atmospheric CO2. If we assume meridional mixing to be zero, then the seasonal variations of carbon in the atmospheric column should be equal
to those of carbon in the continental bionass but opposite to them in sign. This latter value is essentially the difference
between productivity and destructivity of the land biomass Productivity of humid areas at any latitude is proportional to
the diurnal mean solar radiation flux at that latitude. In the present study the temporal variations of this flux are harmonically
approximated. Further, an harmonic approximation is found for expressing the temporal course of biomass destructivity at various
latitudes. Productivity/destructivity oscillations appear to be almost in couterphase but amplitudinally close to each other.
Riassunto Le variazioni stagionali del contenuto di carbonio nell'oceano sono piccole rispetto a quelle che si verificano nell'atmosfera. Il mescolamento atmosferico meridionale non è abbastanza intenso da compensare le variazioni del CO2 atmosferico. Se si ammette che il mescolamento sia zero, le variazioni stagionali del carbonio nella colonna atmo-sferica dovrebbero essere uguali a quelle del carbonio nella biomassa continentale ma opposte a queste ultime come segno. Quest'ultimo valore è essenzialmente la differenza tra la produttività e la distruttività nella biomassa terrestre. La produttività delle aree umide ad ogni latitudine è proporzionale al flusso di radiazione solare diurno medio a quella latitudine. In questo studio si approssimano armonicamente le variazioni temporali di questo flusso. Inoltre si trova un'approssimazione armonica per esprimere l'andamento temporale della distruttività della biomassa a varie latitudini. Le oscillazioni di producttività/distruttività sembrano quasi in controfase ma prossime l'una all'altra per quanto riguarda l'ampiezza.
Резюме Показано, что сезонные изменения содержания углерода в океане малы по сравнению с изменениями в атмосфере. Меридионаляное перемешивание атмосферы не успевает выравнивать атмосферные колебания CO2. В приближении нулевого меридионляного перемешиваиия сезонные колебания содержания углерода в атмосферном столбе равны по величине и противололожны по знаку изменению содерзания углерода в континентальной биомассе, иоторое равно разности продуктивности и деструктивности. Продуктивность гумидных областей на разных широтах пропорционаляна среднесуточному потоку солнечной радиации на зтих широтах. В работе найдено гармоническое привлижение для изменения во времени последних величин. С помощью зтих данных определено гармоническое приближение для поведения во времени деструктивности на ражных широтах. Колебание продуктивности и деструктивности оказались происходящими почти в противофазя с близкими по величине амплитудами.相似文献
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T. K. Meleshko D. M. Il’gach N. N. Bogorad N. V. Kukarkina E. N. Vlasova A. V. Dobrodumov I. I. Malakhova N. I. Gorshkov V. D. Krasikov A. V. Yakimanskii 《Polymer Science Series B》2010,52(9-10):589-599
Multicentered initiators for the controlled (pseudoliving) radical polymerization are synthesized via polymer analog transformation of hydroxyl-containing polyimides based on o-aminophenols. Conditions providing variations in the degree of functionalization of polyimides by initiating 2-bromoisobutyrate groups are determined, and optimum conditions for the preparation of macroinitators containing the above groups in each repeat polyimide unit are found. Via the method of controlled radical polymerization with the atom transfer on multicentered macroinitiators in the presence of complexes of univalent copper halides, graft copolymers of poly(methylmethacrylate) on polyimide backbone are obtained. Molecular-mass characteristics of graft copolymers are studied via multiple-detection size-exclusion liquid chromatography. Preparation of graft copolymers (polymer brushes) with a homogeneous grafting density and a homogeneous length of side chains necessitates grafting of the side chain on the polyimide initiator, which contains initiating groups in each repeat unit. 相似文献
26.
Mikhail V. Gorshkov David M. Good Yaroslav Lyutvinskiy Hongqian Yang Roman A. Zubarev 《Journal of the American Society for Mass Spectrometry》2010,21(11):1846-1851
Ion storage in an electrostatic trap has been implemented with the introduction of the Orbitrap Fourier transform mass spectrometer
(FTMS), which demonstrates performance similar to high-field ion cyclotron resonance MS. High mass spectral characteristics
resulted in rapid acceptance of the Orbitrap FTMS for Life Sciences applications. The basics of Orbitrap operation are well
documented; however, like in any ion trap MS technology, its performance is limited by interactions between the ion clouds.
These interactions result in ion cloud couplings, systematic errors in measured masses, interference between ion clouds of
different size yet with close m/z ratios, etc. In this work, we have characterized the space-charge effect on the measured frequency for the Orbitrap FTMS,
looking for the possibility to achieve sub-ppm levels of mass measurement accuracy (MMA) for peptides in a wide range of total
ion population. As a result of this characterization, we proposed an m/z calibration law for the Orbitrap FTMS that accounts for the total ion population present in the trap during a data acquisition
event. Using this law, we were able to achieve a zero-space charge MMA limit of 80 ppb for the commercial Orbitrap FTMS system
and sub-ppm level of MMA over a wide range of total ion populations with the automatic gain control values varying from 10
to 107. 相似文献
27.
E. S. Demidov A. N. Mikhaylov A. I. Belov M. V. Karzanova N. E. Demidova Yu. I. Chigirinskii A. N. Shushunov D. I. Tetelbaum O. N. Gorshkov E. A. Evropeitsev 《Physics of the Solid State》2011,53(12):2415-2420
It has been shown that the presence of silicon nanoparticles in a layer of porous silicon saturated with tungsten-tellurite
glass causes an increase in the photoluminescence quantum efficiency of erbium (1530 nm) by an order of magnitude in the case
of long-wavelength excitation and an enhancement of the ytterbium photoluminescence (980 nm) by almost 50 times and erbium
photoluminescence by 25 times in the case of short-wavelength pumping. This luminescence enhancement is explained by the formation
of additional channels of transfer of external excitation by silicon nanocrystallites in porous silicon to impurity ytterbium
and erbium ions in tungsten-tellurite glass. 相似文献
28.
29.
A. A. Goloborod’ko C. Mayerhofer A. R. Zubarev I. A. Tarasova A. V. Gorshkov R. A. Zubarev M. V. Gorshkov 《Journal of Analytical Chemistry》2010,65(14):1462-1468
Database search is the most popular approach used for the identification of peptides in contemporary shotgun proteomics; it
utilizes only mass spectrometric data. In this work, we introduce three criteria for the verification of peptide identification;
these are based on the analysis of data orthogonal to tandem mass spectra. The first one utilizes chromatographic retention
times of peptides. The development of such approaches has been hindered by the relatively low accuracy of retention time prediction
algorithms. In this work, we suggest the use of two independent models of the liquid chromatography of peptides, which increase
the reliability of the results. The second criterion utilizes the mean number of missed tryptic cleavages per peptide. The
third one results from the analysis of the difference between theoretical and experimentally measured peptide masses. The
proposed criteria were applied to the tandem mass spectra of tryptic peptides from rat kidney tissue, which were processed
by the Mascot search engine. All the criteria showed that Mascot significantly overestimated the reliability of an identification.
This conclusion was supported by the PeptideProphet algorithm. 相似文献