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921.
Duralí Mendíl Ahmet Bílgín Yaşar Gök H. Basrí Şentük 《Journal of inclusion phenomena and macrocyclic chemistry》2002,43(3-4):265-270
A new N,N'-substituted diaminoglyoxime (H
2
L) containing a diazatetraoxamacrobicycle [2.2.2B] has been synthesized from an aromatic primary amine attached to the cryptand moiety and cyanogen-di-N-oxide. The BF2
+-capped Co(III) and heterotri-nuclear complexes of thevic-dioxime were prepared. The new compounds werecharacterized by a combination of elemental analysis and 1H NMR,13C NMR, IR and MS spectral data. 相似文献
922.
Jürgen Eichenauer Holger Grothe Jürgen Lehn Alev Topuzoğlu 《manuscripta mathematica》1987,59(3):331-346
On-linear multiple recursive congruential pseudo random number generator with prime modulus p is introduced. Let x, n0, be the sequence generated by a usual linear (r+1)-step recursive congruential generator with prime modulus p and denote by N(n), n0, the sequence of non-negative integers with xN(n)0 (mod p). The non-linear generator is defined by znxN(n)+1·x
N(n)
–1
(mod p), n0, where x
N(n)
–1
denotes the inverse element of xN(n) in the Galois field GF(p). A condition is given which ensures that the generated sequence is purely periodic with period length pr and all (p–1)r r-tupels (y1,...,yr) with 1y1,...,yrp are generated once per period when r-tupels of consecutive numbers of the generated sequence are formed. For r=1 this generator coincides with the generator introduced by Eichenauer and Lehn [2]. 相似文献
923.
924.
Elif Varhan Oral Özge Tokul-Ölmez İsmail Yener Mehmet Firat Zeki Tunay Pınar Terzioğlu 《Analytical letters》2019,52(2):320-336
Aerial parts and roots of the 12 Allium species collected from five localities of Turkey were studied for trace elements (Ag, As, Cd, Co, Cr, Cu, Ni, Pb, Se, Tl, V, and Zn) using inductively coupled plasma mass spectrometry (ICP-MS). A tomato leaves certified reference material was used to characterize the accuracy and precision of the analysis. Each Allium species contained Se (315–2740?µg/kg), Tl (2.75–71?µg/kg), V (77–6790?µg/kg), and Zn (3.73–26.6?mg/kg) which can meet the necessary daily intake of these minerals. In addition, chemometric analyses were performed using correlation analysis, principal component analysis, and hierarchical cluster analysis to determine the association of 12 trace elements in the Allium species. Using chemometrics, the distribution of elements between aerial parts and roots, and geographic collection localities of Allium species were also examined. This study is important the consumers because of the wide consumption of Allium species. This report is the first detailed characterization of the metal content of Allium species. 相似文献
925.
R. J. Speakman E. C. Stone M. D. Glascock A. Çilingiroğlu P. Zimansky H. Neff 《Journal of Radioanalytical and Nuclear Chemistry》2004,262(1):119-127
The assessment of environmental pollution of the coastal areas of the Malaysian Peninsula was done by analyzing the contents of the heavy and trace elements in the bivalves blood clams (Anadara granosa) and green mussels (Perna viridis) and sediments at twenty-two sampling stations to look for prevailing trends. Heavy and trace elements analyzed in this study were As, Cd, Cr, Cu, Pb, Se and Zn. Two techniques, namely the neutron activation analysis (NAA) and atomic absorption spectrophotometry (AAS) were used in the quantitative determination of the heavy metals while Marine Sediment Reference Material (BCSS) and Lobster Hepatopancreas (TORT-1) provided the certified reference materials in the quality assurance control. The potential use of these bivalves as suitable bio-indicators was evaluated from correlation tests based on the concentrations of heavy and trace elements in the sediment-metals system to those in the bivalves. 相似文献
926.
İsmail Yener Mustafa Abdullah Yilmaz Özge Tokul Ölmez Pelin Köseoğlu Yılmaz Yeter Yeşil 《Analytical letters》2019,52(7):1031-1049
The Euphorbiaceae family comprises of about 300 genera and 5000 species primarily distributed in America and tropical Africa. The Euphorbia genus is represented by 105 species and locally named as “Sütle?en” and “Xa?îl” in Turkey. The present study aimed to determine the chemical constituents of E. aleppica, E. eriophora, E. macroclada, E. grisophylla, E. seguieriana subsp. seguieriana, E. craspedia, E. denticulata, E. falcata, and E. fistulosa, and classify them by utilizing the chemometric techniques of principal component analysis (PCA) and hierarchical cluster analysis (HCA). Linoleic acid, 17-tetratriacontane, palmitic acid, and hexatriacontane were the major fatty acids from the gas chromatography–mass spectrometry (GC/MS) analyses. Characterization of 268 constituents of the studied species was achieved by liquid chromatography–ion trap–time-of-flight–mass spectrometry (LC-IT-TOF-MS). Furthermore, a new liquid chromatography–tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous quantitative determination of 11 compounds (quinic acid, protocatechuic acid, rutin, hesperidin, eugenol, p-coumaric acid, piceatannol, scopoletin, dl-kavain, chrysophanic acid, and resiniferatoxin) in these species. The developed method was validated for the linearity, limit of detection, limit of quantification, repeatability, and recovery. 相似文献
927.
Tülay. Bal. Demirci Yüksel Köseoğlu Sadik Güner Bahri Ülküseven 《Central European Journal of Chemistry》2006,4(1):149-159
Four new oxovanadium(IV) compounds were prepared by template reaction of salicyl-, 5-bromosalicyl-and 3-methoxysalicyl-aldehyde
S-methylthiosemicarbazones with 2-hydroxy-, 5-bromo-2-hydroxy-and 3-methoxy-2-hydroxy-benzaldehyde in various combinations.
The compounds were isolated as stable solid compounds with general formula [VO(L)] and characterized by elemental analysis,
conductivity and magnetic measurements, electronic, IR and EPR spectroscopy. The X-band EPR signals recorded from powder forms
of all samples have a single asymmetric line shape and theoretical fit studies proved the presence of axial symmetry around
the paramagnetic vanadium ions. The anisotropic Lande splitting factors take values of g‖ < g⊥ < ge = 2.0023. Orbital energy levels for magnetic electrons were determined from theoretically well fitted Spin Hamiltonian parameters.
The EPR spectra recorded from solution forms almost have isotropic character. 相似文献
928.
Mehmet Çopuroğlu Shane O’Brien Gabriel M. Crean 《Journal of Sol-Gel Science and Technology》2006,40(1):75-82
A hybrid material system consisting of (3-glycidyloxypropyl)trimethoxysilane, dimethyldimethoxysilane and zirconium(IV) n-propoxide was prepared. The influence of processing parameters including Zr content, UV irradiation and sol ageing on the
properties of the resultant thin films was discussed. Refractive index, at 633 nm, and reflectance measurements were performed
and near-field waveguide images of the samples were taken. Optical propagation loss measurements, at 633 nm, were studied.
Film thickness and cross-sectional scanning electron microscopy images were obtained as a function of process conditions.
FT-IR spectroscopy was used to monitor chemical reaction pathways in the system during processing. It was demonstrated that
the crosslinking of epoxy groups in the structure, along with inorganic network formation as a result of sol-gel reactions,
was the primary reason for the changes in the optical and physical properties of the system. As Zr containing species and/or
UV irradiation may be employed to crosslink the epoxy groups in the structure, the optical and physical properties of the
system can be tuned by optimal combination of these two crosslinking methods, as well as sol ageing process. 相似文献
929.
Energy dispersive X-ray fluorescence technique was used for the determination of As, Sr, Mo, Ba, In and Ce in fly ash Afsin-Elbistan power plants using the standard addition method. An annular241Am source was employed for excitation of the K shell of the elements. 相似文献
930.
Eroğlu AE Volkan M Bayramh E Ataman OY Mark HB 《Analytical and bioanalytical chemistry》1996,355(5-6):667-671
In the analytical system suggested, atmospheric hydrogen sulfide reacts with the surface of a filter paper treated with aqueous cadmium chloride and yields a luminescent species whose intensity can be correlated with the analyte concentration in ambient air. It was shown that the luminescent species are CdS solid particles which were formed in a well defined size. The paper luminescence was also tried on polymeric surfaces; polyethyleneoxide, polyvinyl alcohol, ethylcellulose and carboxymethylcellulose were found to give a similar luminescence signal. The system can be used on the tip of an optical fiber for an irreversible, cumulative type of analytical device for hydrogen sulfide determination. The 3s detection limit for the paper luminescence detection system was 7.8 ppb H(2)S. 相似文献