Defect clusters and precipitation/oxidation of MgO-Co1−xO solid solution

MgO and Co_1−xO powders in 9:1 and 1:9 molar ratio (denoted as M₉C₁ and M₁C₉, respectively) were sintered and homogenized at 1600°C followed by annealing at 850°C and 800°C, respectively to form defect clusters and precipitates. Analytical electron microscopic observations indicated the protoxide remained as rock salt structure with complicated planar diffraction contrast for M₉C₁ sample, however with spinel paracrystal precipitated from the M₁C₉ sample due to the assembly of charge- and volume-compensating defects of the 4:1 type, i.e., four octahedral vacant sites surrounding one Co³⁺-filled tetrahedral interstitial site. The spacing of such defect clusters is 4.5 times the lattice spacing of the average spinel structure of Mg-doped Co_3−δO₄, indicating a higher defect cluster concentration than undoped Co_3−δO₄. The {111} faulting of Mg-doped Co_3−δO₄/Co_1−xO in the annealed M₁C₉ sample implies the possible presence of zinc blend-type defect clusters with cation vacancies assembled along oxygen close packed (111) plane.     

长链氨羧络合剂萃取稀土饵

研究了长链氨羧络合剂N,N′-二(十二烷基)乙二胺二乙酸钠(Na2R2Y)的氯仿溶液萃取稀土饵的行为;考察了溶液酸度、络合剂浓度、相比和温度对萃取率的影响.用摩尔比法测定了Na2R2Y与Er3+的络合摩尔比为1∶1;结果表明,Na2R2Y的氯仿溶液对饵的萃取率随络合剂浓度的增大而增大,随温度的升高而降低.     

Synthesis of positively charged lipids containing a 1,3-oxathiolane cycle

Positively charged lipids of the 1,3-oxathiolane series were synthesized by interaction of 2-pentadecyl-5-tosyloxymethyl- or -5-iodomethyl-1,3-oxathiolane with 2-(N,N-dimcthyl-amino)ethanol.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2347–2349, September, 1996.     

Biamperometric neutralisation titrations in non-aqueous solvents applying tin electrode pair for the end-point detection

Summary Tertiary amines and salts of organic acids in acetic anhydride with 5% of acetic acid were titrated applying a biamperometric indicating system consisting of a polarised or unpolarised pair of tin electrodes by means of 0.1 N perchloric acid in glacial acetic acid. Amounts of 15.4–29.8 mg were analysed with average deviations of <0.6%, the results obtained being in a good agreement with those of potentiometry. The biamperometric end-point detection using an indicating system of polarised pair of tin electrodes can be applied for coulometric determinations of these bases with satisfying accuracy. By means of anodic generation of hydrogen ions in the presence of hydroquinone amounts of 0.5–1.0 mg were titrated with average deviations of < 1.3%. The results obtained were compared with those obtained of catalytic thermometric and photometric titrations.

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Biamperometrische Neutralisationstitrationen in nichtwärigen Lösungsmitteln unter Anwendung eines Zinn-Elektrodenpaares als Indicatorsystem

Zusammenfassung Tertiäre Amine und Salze organischer Säuren werden in Acetanhydrid mit 5% Essigsäure durch Titration mit einer 0,1 N Lösung von Perchlorsäure in Essigsäure bestimmt. Das verwendete biamperometrische Indicatorsystem besteht aus einem Paar polarisierter oder nichtpolarisierter Zinnelektroden. Mengen von 15,4–29,8 mg wurden mit einer mittleren Abweichung von <0,6% analysiert. Die Ergebnisse stimmen gut mit denen von potentiometrischen Titrationen überein. Die biamperometrische Endpunkttechnik mit polarisierten Zinnelektroden kann für coulometrische Bestimmungen dieser Basen mit zufriedenstellender Genauigkeit benutzt werden. Durch anodische Erzeugung von Wasserstoffionen in Gegenwart von Hydrochinon wurden Mengen von 0,5–1,0 mg mit einer mittleren Abweichung von < 1,3% titriert. Die Ergebnisse wurden mit denen von katalytisch-thermometrischen und photometrischen Titrationen verglichen.

     

Reagents for new heteroannelation reactions III. 2-(Methylthio)-2-thiazoline

Summary A variety of partly novel tri- and tetracyclic hetero systems were obtained by reaction of heteroaromatic 2-aminoesters with 2-(methylthio)-2-thiazoline, yielding double-annelation of a thiazolo[2,3-b]pyrimido moiety in a one-pot process.On leave from University of Chittagong, Bangladesh     

分子筛改性气—液毛细管柱及其性能考察

以原位合成法制备的分子筛膜对玻璃毛细管内壁进行改性后，成功地制备了常规口径及大口径分配ＳＣＯＴ柱，并对毛细管柱的性能进行了评价。     

19F and 1H NMR spectra of halocarbons

19F NMR chemical shifts and coupling constants are reported for 215 compounds. For 77 of these compounds, 1H NMR spectral data are also given. Long-range couplings, including 8J(F,F) and 5J(F,H), are reported. The complexity of halocarbon spectra owing to the presence of rotational isomers, asymmetric centers, long-range couplings, and chlorine isotope effects are illustrated, and the methods used for analyzing such complex spectra are briefly discussed.     

Computer interactive identification system for polycyclic aromatic hydrocarbons in reversed-phase microcolumn liquid chromatography

Summary A computer interactive identification system is proposed which is based on the relationship between retention and molecular properties such as the size and shape of polycyclic aromatic hydrocarbons (PAHs). This system offers an automatic analytical process for liquid chromatography, providing a reliable identification of the separated components. The identification can be further enhanced by the use of multiple detectors such as a multichannel UV detector. The system can be used for optimization procedures, resulting in a highly automatic complex analytical system.     

On the loss of cadmium, antimony and silver during dry ashing of biological material

Summary The loss of cadmium, antimony and silver during dry ashing of marine weeds, mussels and shrimps was studied with the aid of radioactive tracers. Except for antimony all biological material was labelled by uptake of the radioactive tracers by the organisms while still alive. At an ashing temperature of 500° C and below no significant loss by volatilization of these elements occurs. The results obtained at higher temperatures with cadmium show that the behaviour of this element may depend on the composition of the organic material. Retention on the wall of quartz crucibles did not cause serious losses.

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Über den Verlust an Cadmium, Antimon und Silber bei der Trockenveraschung von biologischem Material

Zusammenfassung Mit Hilfe radioaktiver Tracer wurden die Verluste an Cadmium, Antimon und Silber bei der Trockenveraschung von Seetang, Muscheln und Krabben untersucht. Mit Ausnahme von Antimon wurden alle Materialien mit den Tracern durch Aufnahme im lebenden Zustand markiert. Bei Veraschungstemperaturen von 500° C und darunter konnten keine signifikanten Verluste durch Verflüchtigung der Elemente festgestellt werden. Das Verhalten von Cadmium bei höheren Temperaturen kann von der Zusammensetzung des organischen Materials abhängen. Verluste durch Haften an der Wand des Quarztiegels waren unbedeutend.

     

Phenolic Compounds of Plants of the Scutellaria L. Genus. Distribution, Structure, and Properties

Information on flavones, flavanones, flavanonols, flavonols, chalcones, isoflavones, biflavonoids, lignoflavonoids, and lignane glycosides and stilbenes isolated from plants of the Scutellaria L. genus was systematized and reviewed. A list of 208 phenolic compounds was given according to flavonoid type with an indication of the plant sources, structures, and physicochemical properties and citations of the original articles.