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101.
102.
103.
Ferenc F. Gaál Ljiljana S. Jovanović Zorka S. Jevrić Jolan N. Ilijević Velimir D. Canić 《Mikrochimica acta》1978,69(1-2):27-34
Summary Electroanalytical End-Point Determination of Hydrolytic Precipitation Titrations of Sulphate and OxalateThe possibilities of application of biamperometric and bipotentiometric end-point determination by means of various indicator electrodes are described. Several titrants were used. Best results were obtained with quinhydrone electrodes. Interference levels of several anions were established. The lowest concentration of oxalate and sulphate that can be determined is 5×10–4
M.
Zusammenfassung Die Anwendungsmöglichkeiten der biamperometrischen und bipotentiometrischen Endpunktbestimmung mittels verschiedener Indikatorelektroden wurden beschrieben. Es wurden einige Titranten benützt. Die besten Resultate wurden mit Chinhydronelektroden erhalten. Die störende Wirkung verschiedener Anionen wurde festgestellt. Die geringste bestimmbare Konzentration beider Anionen (Sulfat und Oxalat) ist 5·10–4 M.相似文献
104.
Gaál V Kilár F Acs B Szijjártó Z Kocsis B Kustos I 《Colloids and surfaces. B, Biointerfaces》2005,45(3-4):125-130
Implantation of artificial intraocular lenses into the eye during ophthalmic surgical procedures ensures an unliving surface on which bacterial pathogens may attach and form biofilms. Despite antibiotic treatment bacteria growing in biofilms might cause inflammation and serious complications. In this study the adhesive ability of 7 Staphylococcus aureus and 11 coagulase-negative Staphylococcus (CNS) strains to the surface of acrylic intraocular lenses had been examined by the ultrasonic method. In untreated cases adhesion of the S. aureus and CNS strains did not differ significantly. We could not demonstrate significant differences between the adhesive ability of the standard strains and the clinical isolates. In this study a single – 60 min long – antibiotic (ciprofloxacin and tobramycin) treatment had been applied, that correlate well with the single or intermittant antibiotic prophylaxis of patients. Ciprofloxacin administration was able to reduce significantly the number of attached cells on the surface of acrylic lenses both in the case of S. aureus and CNS strains. Dependence of the effect from concentration could also be demonstrated. Tobramycin treatment was able to inhibit significantly the attachment of S. aureus cells. Despite the debate on antibiotic prophylaxis we presented in our experiments that a single antibiotic administration can decrease the attachment of bacterial cells to the surface of acrylic intraocular lenses, and might be effective in the prevention of postoperative endophthalmitis, that is a rare but serious complication of ophthalmic surgery. 相似文献
105.
We study the intersection of a subvariety X of an abelian variety A over with the union of all the algebraic subgroups of A of given dimension d. Our main result states that if we remove a suitable exceptional subset from X and if d is small enough then the intersection enjoys a Northcott-like property: the points of bounded height on it form a finite
set. The condition on d involves only the dimension of X and the structure of A up to isogenies. We show how it can be weakened if we assume certain conjectures in the direction of an abelian version of
Lehmer's problem. The theorem is especially meaningful when X is a curve since it is then possible to bound the height and hence to prove finiteness of the set under consideration. This
generalises the result of E. Viada on powers of elliptic curves and is analogous to work of E. Bombieri, D. Masser and U.
Zannier on tori, whose general strategy we follow. 相似文献
106.
Conclusions In the UV irradiation (wavelength interval 236–800 m) of polypropylene (atactic and isotactic) and polyethylene at temperatures of 77–123°K, a substantial amount (1018–1019 g–1) of radicals of various types are formed. Hydroperoxide groups are among the main sources of radicals in the case of oxidized polypropylene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 778–783, April, 1967. 相似文献
107.
Katalin Gaál-Nagy 《Central European Journal of Physics》2010,8(5):833-842
I present a first-principles investigation of the vibrational properties of the chiral molecule 3-tert-butylcyclohexene. The
vibrational density of states (vDOS) of the two existing conformers has been calculated ab initio within the framework of density-functional theory and density-functional perturbation theory, using both the local-density
approximation and the generalized-gradient approximation for the exchange-correlation potential. The vDOS of the two conformers
are very similar. The vDOS has been investigated with respect to contributions of the cyclohexene ring and the tert-butyl
group and also regarding the localization of vibrational modes. Additionally, the eigendisplacements of characteristic modes
of 3-tert-butylcyclohexene have been analyzed. 相似文献
108.
Gałezowska J Janicki R Mondry A Burgada R Bailly T Lecouvey M Kozłowski H 《Dalton transactions (Cambridge, England : 2003)》2006,(36):4384-4394
The proton and metal complex equilibria of trans-cyclohexane-1,2-diamine-N,N,N',N'-tetrakis(methylenephosphonic acid) (CDTP) with lanthanide(iii) ions, where Ln(III) = La(III), Nd(III), Sm(III), Eu(III), Gd(III), Tb(III), Ho(III) and Lu(III) were studied. The stoichiometry, protonation and complex formation constants were determined by potentiometric titration at 25.0 degrees C and ionic strength of 0.1 mol dm(-3) (KCl). All metal ions form several species: [LnH4L]-, [LnH3L](2-), [LnH2L](3-), [LnHL](4-), [LnL](5-), [LnH(-1)L](6-) and [LnH(-2)L](7-) in the pH range between 2 and 11. The stability constants log beta(LnL) were found to be between 14.7 and 16.7. The studied complexes were also characterized by spectroscopic methods (31P NMR, UV-Vis absorption and emission spectroscopy). These studies allowed to reveal a distinct structural change of the Ln(III)-CDTP complex which occurs between protonated and hydroxy species in solutions at pH around 7.5. The major change is caused by the involvement of both nitrogen donors in the metal ion coordination occurring in ML species. The data obtained from UV-Vis spectroscopy allowed to draw conclusions about complex symmetry and to estimate a number of coordinated water molecules. The hydration number or more precisely the number of two OH oscillators was found to be approximately one in all species formed over the pH range between 5 and 10. The structure of the major hydroxy complex was supported by X-ray crystallographic data. The crystal structures of the Eu(III) and Tb(III) complexes clearly show that the CDTP ligand is coordinated to the Ln(III) ion by two nitrogen and four oxygen atoms in such a way that only one oxygen atom from each phosphonic group is placed in the lanthanide inner sphere. The monomeric complex anion is connected to a symmetry related ion through short hydrogen bonds formed by two hydroxy ions and one water molecule. In this way the two neighbouring anions form a quasi-dimer in which one of the Ln(III) ion is seven-coordinate (two N atoms, four O atoms and one hydroxy ion) and the other is eight-coordinate (two N atoms, four O atoms, one hydroxy ion and one water molecule). 相似文献
109.
Bubbling in unbounded coflowing liquids 总被引:1,自引:0,他引:1
An investigation of the stability of low density and viscosity fluid jets and spouts in unbounded coflowing liquids is presented. A full parametrical analysis from low to high Weber and Reynolds numbers shows that the presence of any fluid of finite density and viscosity inside the hollow jet elicits a transition from an absolute to a convective instability at a finite value of the Weber number, for any value of the Reynolds number. Below that critical value of the Weber number, the absolute character of the instability leads to local breakup, and consequently to local bubbling. Experimental data support our model. 相似文献
110.
Mirosław Gałązka 《Phase Transitions》2013,86(11-12):1125-1132
An equation of state accounting for coupling of the primary order parameter (here the polarization) with a secondary order parameter (here a strain ?) is used to describe the temperature dependences of the spontaneous polarization and of the electric susceptibility on external biasing field. A new scaling invariant and its explicit expression are given. The theory is exemplified by the effective critical behavior of the molecular ferroelectric crystals (CH3NH3)5Bi2Cl11 (MAPCB) and (CH3NH3)5Bi2Br11 (MAPBB). 相似文献