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21.
22.
I. Ursu I. Apostol M. Dinescu I. N. Mihăilescu A. Popa A. M. Prokhorov V. I. Konov N. I. Chapliev 《Applied Physics A: Materials Science & Processing》1984,34(2):133-138
Progressive damage of aluminium mirrors subjected to microsecond pulsed TEA-CO2 laser irradiation in air, at incident intensity levels lower than the thresholds for melting induction and air breakdown ignition, was evidenced by electron microscopy investigations. A simple model was developed accounting for the results of our experimental studies. 相似文献
23.
Conclusions
From Stachys annua L. have been isolated the diacetate and two monoacetates of a new diterpenoid C20H32O3, which has been named stachysolone. It has been shown that stachysolone is a bicyclic ,-unsaturated ketone containing secondary and tertiary hydroxy groups.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 1, pp. 7–10, 1969 相似文献
24.
A microsecond periodic pulse was applied on thin probes in a positive column of a neon or helium glow discharge. The local transient phenomena provoked by this pulse were detected by a photomultiplier and presented in a time-distance display. They are qualitatively described and explained. The results are in good agreement with previous theories. 相似文献
25.
In this paper we consider two von Neumann subalgebras and of a type II1 factor . For a map φ on , we define
26.
A. P. Nizovtsev S. Ya. Kilin F. Jelezko I. Popa A. Gruber C. Tietz J. Wrachtrup 《Optics and Spectroscopy》2003,94(6):848-858
The spin-selective photokinetics of a single matrix-isolated impurity molecule with a triplet-triplet optical transition, T 0–T 1, is considered and the manifestations of the photokinetics in the fluorescence excitation spectra and intensity autocorrelation functions g (2)(τ) of the molecule undergoing narrow-band optical excitation is studied to resolve the fine structure of the transition. The rates of intersystem crossings (ISCs) T 1→S→T 0 to and from a nonradiating singlet state S of the molecule and the rate of population relaxation among the ground (T 0) state sublevels can be obtained from the spectra and g (2)(τ) using the analytical expressions obtained. New experiments on an individual NV defect center in nanocrystals of diamond, where, for the first time, the fine structure of its triplet-triplet 3 A-3 E zero-phonon optical transition (~637 nm) at 1.4 K was resolved, are interpreted. It is concluded that the rate of the ISC transition from the m S =0 sublevel of the excited 3 E state to the singlet 1 A state (~1 kHz) is much slower than the rates from the m S =±1 substates, while the rates of ISC transitions to different m S substates of the ground 3 A state are close to each other (~1 Hz). As a result, only the optical transition between m S =0 sublevels in the 3 A-3 E manifold contributes strongly to the fluorescence. The experimentally observed double-exponential decay of the g (2)(τ) function is explained by the two pathways available to the center for it to leave the S state: (i) the S→ T 0(m S )=0) transition and (ii) the S→T 0(m S =±1) transitions followed by the slow spin-lattice relaxation T 0(m S =±1)→T 0(m S =0) (rate ~0.1 Hz). The work is important for studies where the NV center is used as a single photon source or for quantum information processing. 相似文献
27.
We describe a simple method for tracking the course of microbial degradation of polysaccharide-rich feedstocks. The method
involves determining total polysaccharides present in the feedstock, measured in glucose equivalents, relative to the fractional
component of polysaccharides exhibiting 2,3-dinitrosalycylic acid aldehyde activity. The ratio of total polysaccharide to
aldehyde activity, defined as the end-point fragmentation (EPF) index, is then calculated and tracked as it shifts as microbial
degradation of polysaccharide-rich feedstock progresses. While degradation occurs, the EPF index falls. It bottoms out at
an asymptotic limit marking the point in time where further degradation of the polysaccharide-rich feedstock has ceased. The
EPF index can be used to follow the progressive breakdown of composting polysaccharide-rich waste. It may also have applicability
as a means of tracking the turnover of polysaccharides in other complex environments including soil, sediments, wetlands,
and peat bogs. 相似文献
28.
R.J.M. Konings K. Popa E. Colineau F. Wastin 《The Journal of chemical thermodynamics》2008,40(2):220-224
The heat capacity of calcium monouranate CaUO4 and strontium monouranate SrUO4 have been measured over the temperature range (2 to 300) K. The results are significantly different from earlier measurements, confirming the conclusions from our previous study on BaUO4. The standard entropy at T = 298.15 K of orthorhombic α-SrUO4 is consistent with the values for the isostructural BaUO4 as well as the alkali uranates Na2UO4 and Cs2UO4. The standard entropy of the rhombohedral CaUO4 is appreciably different, which is attributed to the different structures of the uranium sublattices. 相似文献
29.
Mihaela Frunza Gabriela Lisa M. I. Popa N. D. Miron Denisa Ileana Nistor 《Journal of Thermal Analysis and Calorimetry》2008,93(2):373-379
The thermal behavior of the new inorganic-organic nanohybrid materials obtained by intercalation of chloramphenicol and salicylate
into layered double hydroxides (LDHs) by direct synthesis method, anion exchange reaction and the reconstruction method was
evaluated by dynamic thermogravimetric analysis in air, at heating rates of 5°C min−1. The XRD patterns of the samples are characteristic for those of well crystallized solids with layered double hydroxide structures.
The FTIR spectroscopy results show the presence of the organic compound within the network structure of the synthesized LDHs.
The kinetic parameters (reaction order (n) apparent activation energy (E
a) and pre-exponential factor (lnA) were calculated by the Coats-Redfern method. The compensation effects were determined. 相似文献
30.
S. Dumitriu M. I. Popa I. Hăulică A. Crîngu A. Stratone 《Colloid and polymer science》1989,267(7):595-599
Ampicillin and chloramphenicol were coupled on xanthan by activation by dicyclohexyl-carbodiimide. Drug release from the support was studied in vitro for ampicillin, and in vitro and in vivo conditions for chloramphenicol. 相似文献