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61.
Constructions introduced by Dirac for singular Lagrangians are extended and reinterpreted to cover cases when kernel distributions are either nonintegrable or of nonconstant rank, and constraint sets need not be closed. 相似文献
62.
Arūnas Jagminas Marija Kurtinaitienė Kęstutis Mažeika Ričardas Rotomskis Gediminas Niaura Algirdas Selskis 《Journal of nanoparticle research》2011,13(9):4133-4142
Developing of a simple method for the fabrication of superparamagnetic iron oxide nanoparticles (Nps) is still a challenge for materials scientists. This work reveals a way to fabricate especially stable ferrofluids from spherical Nps of magnetite using the co-precipitation method, for which a new (diglycolic acid) stabilizer was applied. The Nps of the average size of ~7.4–16.5 nm were characterized by means of high resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), selective area electron diffraction (SAED), Raman, FTIR and Mössbauer spectroscopy. The stabilization effect of the diglycolic acid for the growth of superparamagnetic Nps growth was discussed on the basis of experimental results. 相似文献
63.
Jacek Achrem‐Achremowicz Elżbieta Kępczyńska Marek Żylewski Zbigniew Janeczko 《Biomedical chromatography : BMC》2010,24(3):261-267
A series of superlipophilic or highly lipophilic semisynthetic betulin derivatives was prepared and their relative lipophilicity was measured by reversed‐phase thin‐layer chromatography (RP‐TLC) at different pH values using 1,4‐dioxane–acetate buffer mixtures as mobile phases. Cholesterol, 17β‐estradiol and pure betulin were used as the reference compounds. Linear relationships were found between RM values and 1,4‐dioxane concentrations in the mobile phases. LogP values were also calculated with computer programs ACD/LogP (ChemSketch 11.0, Advanced Chemistry Development Inc.) and ClogP (Daylight Chemical Information Systems Inc.). The empirical and theoretical data were compared, and the RM0 values correlated well with logP. Two of the synthesized betulin derivatives are reported for the first time. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
64.
C. Stępniak 《Annals of the Institute of Statistical Mathematics》1987,39(1):563-573
Summary It is shown that in linear estimation both unbiased and biased, all unique (up to equivalence with respect to risk) locally
best estimators and their limits constitute a complete class. 相似文献
65.
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
66.
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
67.
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
68.
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
69.
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
70.
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