Studies on the solvent extraction of yttrium thenoyltrifluoroacetonate

Studies of extractions of yttrium from aqueous solution into chloroform, benzene, methyl isobutyl ketone, and mixtures of these solvents, containing thenoyltrifluoroacetone are described. The effects of reagent concentration, added n-butylamine, and added fluoride were investigated. Values of pH$\text{1}\text{2}$ and P_e were determined, and identifications of the involved species are suggested.     

Polystyrene resins with immobilized polyamines: Preparation,characterization, and ability to bind Cu(II) ions

Three polyamine ligands, ethylenediamine (EDA), diethylenetriamine (DTA), and triethylenetetramine (TETA), were bound to three chloromethylated “popcorn” polystyrene resins (16, 50, and 100% phenyl ring substitution) with the use of pyridine as the reaction medium. The rate of chloride displacement decreased with increasing molecular weight of the amine and higher degree of resin chloromethylation, while the extent of multiple attachments to the polymer matrix increased. The additional crosslinking, a result of multiple attachments, caused the polyamine resins to swell to a lesser extent in pyridine and water. The ability of the insoluble polyamine–polystyrene resins to chelate Cu²⁺ ions from dilute solutions (200 ppm) was determined at pH 5. With EDA resins the capacity for Cu²⁺ increased with increasing amount of the bound polyamine, with DTA it remained unchanged, while with TETA it was found to decrease.     

深圳市1408例儿童发中钙,铁,镁含量调查与分析

用火焰原子吸收法检测了深圳市１４０８例１３岁以下儿童发中钙，铁，镁的元素含量，并探讨了元素含量与年龄，性别的关系，结果显示，性别差异有显著意义，钙，镁含量随年龄增长有相似变化。     

A convenient synthesis of cis and trans 4-tert-butoxycarbonyl-substituted cyclohexylglycine

A novel synthesis of cis and trans substituted 4-tert-butoxycarbonyl cyclohexylglycines via asymmetric aminohydroxylation of vinyl styrene followed by reduction of the aromatic ring and subsequent oxidation is reported.     

STRUCTURE OF DYE AGGREGATES AND THE MECHANISM(S) OF PHOTOSENSITIZATION OF AgBr*,†

Abstract— This paper reports the present conclusions of an extended investigation on photo-sensitization of silver bromide. A general molecular packing structure for dye aggregates on the AgBr (111) surface is proposed. This structure, along with the observed spectral absorption displacements of small aggregates, is used to elucidate the phenomena of antisensitization and supersensitization. Supersensitization is seen as a partitioning of large dye aggregates into small aggregates by a deliberately added second component or by gaps between the aggregates. This partitioning isolates antisensitizing dye in a small fraction of the aggregates and minimizes its effect. The smallest aggregates are least likely to contain an antisensitizer, and show the highest quantum efficiency for photoconductivity and photographic action. Photoconductivity measurements establish that supersensitization occurs before the electron appears in the AgBr phase.
The question of direct electron injection vs. energy transfer as mechanisms for AgBr photosensitization is examined in terms of radiationless transfer to surface Ag₂S on AgBr. The absorption of surface Ag₂S is shown to be adequate for acceptance of Förster transfer from the dye, and surface Ag₂S is known to be photographically active. However, this mechanism is inefficient, and inadequate to account for observed high efficiency infrared sensitization. Direct electron injection is seen as the more probable mechanism for efficient dye sensitization of AgBr.     

Determination of panaxadiol and panaxatriol in ginseng and its preparations by capillary supercritical fluid chromatography (SFC).

Capillary supercritical fluid chromatographic (SFC) method has been developed for the determination of panaxadiol and panaxatriol in ginseng and its preparations. 0.1 g ginseng or an appropriate amount of its preparations was hydrolysed by 15% H2SO4 in an ethanol:water (1:1 v/v) solution for 4 h followed by 15% NaOH for 0.5 h. The mixture was extracted by cyclohexane. The cyclohexane extracts were purified by a partition column and concentrated by an adsorption column and then analysed by SFC. Methyltestosterone was used as the internal standard.     

富烯碳原子簇的石墨层间闭合形成机理

本文提出了富烯碳原子簇的石墨层间闭合形成机理，由该机理推出的许多结果与实验事实符合很好。我们认为碳原子簇自由基的快速淬灭及其淬灭速度是富烯碳原子簇形成及其丰度的决定因素。由此得出富烯碳原子簇在给定实验条件下产生的必然性，并预言不同大小的富烯碳原子簇可以通过优化实验条件选择性地合成。     

Mass spectrometric investigation of bimolecular compounds

Two points involving molecular structure have been investigated using mass spectrometry. First, mass spectra have been obtained that indicate a rapid means for differentiating bimolecular compounds from other structural isomers. Second, the mass spectrometric method has been used to evaluate bonding within bimolecular compounds. Quinone compounds have been reacted with dhydroxybenzene compounds to produce quinhydrone products, and upon mass spectrometric analysis, the quinhydrones decompose to regenerate derivatives of the starting materials. Evaluation of the decomposition products suggests that the hydroxyl hydrogens are involved in a resonance structure, and while in symmetrical quinhydrones, the hydroxyl hydrogens are probably associated equally with each reactant, unsymmetrical quinhydrones generate an unbalanced electronic distribution that eliminates the complete equivalency of the hydrogens.     

Determination of phosphite,hypophosphite, tellurium and mercury

A new catalytic oxidation procedure, involving the use of a cerium(IV) sulfate reagent in perchloric acid with a mixed silver(I)—manganese(II) perchlorate catalyst, has been developed for the determination of phosphite, hypophosphite, and tellurium. By this method 15—100 mg of phosphite, 5—35 mg of hypophosphite, and 10—105 mg of tellurium may be determined with standard deviations of ±0.17, ±0.32, and ±0.21% respectively. A direct titration procedure for mercury(I) is described using a ceric perchlorate solution as titrant with the mixed catalyst system. Samples from 65–510 mg may be analyzed with a standard deviation of ±0.36%.