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61.
Determination of neomycin trisulphate (NMS) in a dosage form (Neox and Neosol) was carried out by capillary isotachophoresis
(cITP) with conductometric detection. The following electrolytes: leading: 10 mmol dm−3 sodium acetate + 0.08 % hydroxyethylcelulose (HEC) and acetic acid to pH = 5.5, and terminating: 10 mmol dm−3
β-alanine were tested for isotachophoretic separation of NMS. The calibration curve was linear over the range of 10.00 mg dm−3 to 100.00 mg dm−3 with LOD = 5.69 mg dm−3 and LOQ = 18.96 mg dm−3. The results were compared to the conductometric determination of NMS with: ammonium molybdate (VI), silver nitrate (V) and
Reinecke salt. Good accuracy was obtained from conductometric titration of NMS with Reinecke salt, the recoveries being as
follows: 100 % (RSD = 1.99 %); 96.17 % (RSD = 2.10 %) and 95.22 % (RSD = 1.55 %) for NMS in pure form, Neosol and Neox, respectively. 相似文献
62.
Więckowska Anna Bajda Marek Więckowski Krzysztof Malawska Barbara 《平面色谱法杂志一现代薄层色谱法》2010,23(5):359-364
JPC – Journal of Planar Chromatography – Modern TLC - This paper reports an investigation of physicochemical properties of four series of carbamates of 3-hydroxy and... 相似文献
63.
V. Sydorchuk S. Khalameida V. Zazhigalov J. Skubiszewska-Zięba R. Leboda 《Journal of Thermal Analysis and Calorimetry》2010,100(1):11-17
Physicochemical processes during thermal treatment of vanadium and phosphorus oxides mixture (1) as well as with diammonium
hydrophosphate (2) in the closed system (autoclave) have been studied. In the first case, at 300 °C, the defective structure
γ-VOPO4 is formed and in the second case, there was established possibility of synthesis of vanadyl hydrophosphate—the precursor
of vanadyl pyrophosphate (the catalyst of n-butane oxidation to maleic anhydride). At the same time, various phases of mixed ammonium and vanadium phosphates were obtained
at lower and higher temperatures. 相似文献
64.
Waldemar Tomaszewski Vladimir M. Gun’ko Roman Leboda Jadwiga Skubiszewska-Zięba 《Central European Journal of Chemistry》2010,8(4):750-757
Solid phase extraction (SPE) of methoxy- and methylenedioxyamphetamines from diluted aqueous solutions was investigated on
carbon and polymeric adsorbents of different textures and chemical compositions. Those adsorbents were applied cartridges
packed with three chemically modified carbons prepared from plum stones (initial A2PS, oxidized A2PS-O, and reduced A2PS-H)
and commercially available adsorbents (polymeric LiChrolut EN, graphitized Hypercarb and Carboprep). Several factors influence
the recovery rates of amphetamine derivatives such as the polarity of adsorbates (free energy of salvation), the specific
surface area and surface composition of adsorbents, and the solvent characteristics. Different combinations of these factors
affect the recovery rate (R1) for high- and low-surface area adsorbents. The minimal R1 values are observed for an amphetamine
derivative at a maximal solvation effect and for a set of amphetamines adsorbed on graphitized carbons.
相似文献
65.
M. Motyka F. Janiak K. Ryczko G. Sęk J. Misiewicz A. Bauer R. Weih S. Höfling M. Kamp A. Forchel 《Opto-Electronics Review》2011,19(2):137-139
Modulation spectroscopy in its Fourier-transformed mode has been employed to investigate the optical properties of broken
gap ‘W’-shaped GaSb/AlSb/InAs/InGaSb/InAs/AlSb/GaSb quantum well structures designed to emit in the mid infrared range of
3–4 μm for applications in laser-based gas sensing. Besides the optical transitions originating from the confined states in
the type II quantum wells, a number of spectral features at the energy above the GaSb band gap have been detected. They have
been analyzed in a function of InAs and GaSb layer widths and ultimately connected with resonant states in the range of AlSb
tunneling barriers. 相似文献
66.
This paper discusses adaptive finite element methods for the solution of elliptic eigenvalue problems associated with partial differential operators. An adaptive method based on nodal-patch refinement leads to an asymptotic error reduction property for the computed sequence of simple eigenvalues and eigenfunctions. This justifies the use of the proven saturation property for a class of reliable and efficient hierarchical a posteriori error estimators. Numerical experiments confirm that the saturation property is present even for very coarse meshes for many examples; in other cases the smallness assumption on the initial mesh may be severe. 相似文献
67.
Tail asymptotics of supremum of certain Gaussian processes over threshold dependent random intervals
Let {X(t),t ≥ 0} be a centered Gaussian process and let γ be a non-negative constant. In this paper we study the asymptotics of \(\mathbb {P} \left \{\underset {t\in [0,\mathcal {T}/u^{\gamma }]}\sup X(t)>u\right \}\) as \(u\rightarrow \infty \) , with \(\mathcal {T}\) an independent of X non-negative random variable. As an application, we derive the asymptotics of finite-time ruin probability of time-changed fractional Brownian motion risk processes. 相似文献
68.
Adam Osękowski 《Central European Journal of Mathematics》2014,12(8):1198-1213
We study sharp weak-type inequalities for a wide class of Fourier multipliers resulting from modulation of the jumps of Lévy processes. In particular, we obtain optimal estimates for second-order Riesz transforms, which lead to interesting a priori bounds for smooth functions on ? d . The proofs rest on probabilistic methods: we deduce the above inequalities from the corresponding estimates for martingales. To obtain the lower bounds, we exploit the properties of laminates, important probability measures on the space of matrices of dimension 2×2, and some transference-type arguments. 相似文献
69.
Piotr Jędrzejewicz 《Central European Journal of Mathematics》2014,12(8):1278-1284
We prove that an irreducible polynomial derivation in positive characteristic is a Jacobian derivation if and only if there exists an (n-1)-element p-basis of its ring of constants. In the case of two variables we characterize these derivations in terms of their divergence and some nontrivial constants. 相似文献
70.
Łukasz Dębowski 《Journal of Theoretical Probability》2014,27(2):539-551
We investigate stationary hidden Markov processes for which mutual information between the past and the future is infinite. It is assumed that the number of observable states is finite and the number of hidden states is countably infinite. Under this assumption, we show that the block mutual information of a hidden Markov process is upper bounded by a power law determined by the tail index of the hidden state distribution. Moreover, we exhibit three examples of processes. The first example, considered previously, is nonergodic and the mutual information between the blocks is bounded by the logarithm of the block length. The second example is also nonergodic but the mutual information between the blocks obeys a power law. The third example obeys the power law and is ergodic. 相似文献