Ultrastructures in the Spirotheca of Fusulinella (Fusulinid foraminifer)

An SEM study has been conducted to examine the ultrastructures in the spirotheca of Fusulinella and to reveal the ultra-features of the basic layers consisting of the spirotheca of Fusulinella. The study has demonstrated that the diaphanotheca in the spirotheca of Fusulinella could be considered as a secondary structure.     

Study on the Vortex of the Qinghai-Xizang (Tibet) Plateau in Summer

In this paper an ideal model for the formation and development of the Qinghai-Xizang Plateau vortex is presented by a large number of statistical data and typical case studies. It points out that the Plateau vortex is shallow and thermal originated from a strong heat source near the surface of the west of the Plateau. Then moving eastward , it develops and becomes stronger and thicker with larger upward vertical velocity, and causes great precipitation in the middle Plateau. But at this time the heat source in the vortex becomes weaker, and even the heat sink occurs near the surface. Consequently, it disappears in a cold trough with a strong heat sink in the east of the Plateau. The heat source (sink) is mainly determined by the vertical eddy flux convergence (divergence) of the sensible heat caused by the cumulus convection and turbu-lance. Both the nonuniform heating (cooling) at the surface and the convergence (divergence) of the eddy kinetic energy coact and play an important role in the genesis (di     

Polymerization of α-methylstyrene in the solid (frozen) state

Russian Chemical Bulletin -     

Model Study of Basin Soil Loss (BSL) in the Loess Plateau of China (Ⅱ)

According to the influence of underlayer factor upon the basin erosion and in the support of Geographic Information System (GIS) of Loess Plateau(LPIS), the Gushanchuan Basin is divided into several regions with different erosion intensity. Correlating them to the BSL quantity, the complete soil loss model is established. By using this model, the soil loss quantity of the whole basin as well as each erosion intensity region can be estimated.     

Effects of Y (Ⅲ) Ions on the Fluorescence Properties of Ce(Ⅲ) Ion and the Organic Ligands in the Complex

The enhancement effects of Y ( Ⅲ) ions on the fluorescence of Ce ( Ⅲ) in Ce ( Ⅲ)-Y ( Ⅲ)-PMMA (polymethylmethacrylate ) or Ce ( Ⅲ)-Y ( Ⅲ)-PVC (polyvinyl chloride ) complex systems were observed. The influence of Y ( Ⅲ) ions on the emission spectra of PMMA ligands in PMMA-Y ( Ⅲ) and the fluorescent enhance- ment of Y( Ⅲ) on Ce( Ⅲ) emission in PMMA-Ce-Y by Y( Ⅲ) ion were studied. It was also of interest to note that when Y ( Ⅲ) ions were added into PMMA and into bpy(bipyridine ), respectively, the emission spectrum of PMMA ligands was split into fine structure bands by Y ( Ⅲ), and the fluorescence intensities of bpy ligands in bpy-Y ( Ⅲ) complexes were considerably increased.     

Model Study of Basin Soil Loss (BSL) in the Loess Plateau of China (Ⅰ)

Rain is the main motive force of erosion in the Loess Plateau of China. The relationship between rain and basin soil loss (BSL) is the base for establishing BSL model. Based on areo image interpretation, site investigation and analysis of 30-year rain-hydrological data of the study area——the Gushanchuan River Basin which is a branch of the middle reaches of the Yellow River basin as well as one of the intense erosion centres, the BSL features have been revealed. According to the features, the structure of the BSL model is proposed as follows: C·R =S, where C, R and S represent the factor of underlayer, rain and BSL quantity, respectively.Then by using the methods of multivariate statistical analysis, the dominant rain specific elements that affect the BSL and the corresponding formula of the relationship between rain and BSL have been determined as P_m and I_a, and respectively. With this formula the BSL quantity of every rainfall can be estimated. The estimated accuracy can be satisfied after correc     

Theoretical Investigations of the Inclusion Processes of (4-tert-butylphenyl) (3-sulfonatophenyl) (phenyl) Phosphine in β-Cyclodextrin

Quantum mechanical calculations on the (4-tert-butylphenyl)(3-sulfonatophenyl) (phenyl) phosphine/-cyclodextrin inclusion complex werecarried out using semi-empirical calculations. Inclusion process pathways are describedand the most probable structures of the 1:1 complex are sought through a global potentialenergy scan. The calculations suggest that the most stable structure is obtained whenthe aromatic ring bearing the tert-butyl group is includedinto the hydrophobic cavity of the -cyclodextrin from theside of the primary hydroxyl groups.     

Analysis of the Probability of the Mössbauer Effect in Iron(III) β-Diketonates

The probability of the Mössbauer effect f has been evaluated and the Debye temperatures of intermolecular vibrations _M at 295 and 78 K have been determined for ten Fe(III) -diketonates, which are complexes of molecular type. Variation of _M with temperature and molecular mass M has been found; in the latter case, _M decreases as M increases. As a result of this antibatic change in _M and M, the effect of a decreased energy of intermolecular interaction dominates the effect of increased molecular mass, and f decreases in conformity with the prediction provided by the molecular crystal model.     

Determination of the apparent standard potential of the Dy/Dy(Ⅲ) system in the LiCl-KCl eutectic

The apparent standard potential of Dy/Dy(III) system in the LiCl-KCl eutectic has been determined by the logarithmic analysis of the semi-integrals of voltammograms, logarithmic analysis of chronopotentiograms and the open circuit potentiometry. The dysprosium equilibrium potentiab for various concentration of dysprosium chloride in the LiCl-KCl eutectic melt between 400-500℃ were first determined experimentally, and the apparent standard potential of this system and its temperature dependance have been calculated.     

Involvement of ·OH radicals in the mechanism of excitation of the uranyl ion in the chemiluminescent oxidation of U(IV) by atmospheric oxygen in aqueous solutions of perchloric acid

The chemiluminescence (CL) kinetics in U(IV) oxidation by atmospheric oxygen in aqueous HClO₄ has been investigated. The CL quantum yield (η_CL, E/(mol U(IV))) in this reaction is 1.4 × 10^?8. The elementary event generating the CL emitter, which is the electronically excited uranyl ion *(UO ₂ ²⁺ ), is electron transfer from the uranyl ion UO ₂ ⁺ to the oxidizer (^·OH radical). The Ag⁺ ion quenches CL, and the Cu²⁺ ion enhances CL.     

Aging of the paint palette of Valerio Castello (1624–1659) in different paintings of the same age (1650–1655)

It is well known, from ancient Egypt, that some pigments and colourants can change with time for light effect or chemical attack. Cennino Cennini in the fifteenth century in his book “Il libro dell’arte o trattato della pittura” describes the use of many pigments and their degradation. He was aware of the problems and was able to suggest the answers in the use of pigments on several supports, but he could not understand the physical–chemical reason of the alteration processes. In this study, we point out the aging effects in seven paintings, practically of the same period (1650–1655). We considered in particular green, white and blue pigments of the palette of Valerio Castello. About 150 spots were selected on works painted on four different supports, canvas, wood panel, copper and slate. For each point, several determinations were carried on the pigments and decomposition products, aiming to determine the state of conservation of the paintings, the nature of the pigments, their alteration and if the support can affect the kinetics of degradation.     

Adsorptive Stripping Voltammetric Study of the Enhancement of Copper(Ⅱ) in Phosphate and Carbonate media and in the Presence of Silicate

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Photolysis of oxygen saturated ethers in the presence of Sn(Ⅱ) or Cu(Ⅱ) salts

Photolysis of diethyl ether-oxygen charge transfer complex in the presence of Sn(Ⅱ)or Cu(Ⅱ)salts gave higher yields of the oxidation products,ethyl acetate,acetaldehyde,ethanol,ethyl formate and methanol compared with those without the salts.In addition,the photolysis of an oxygen saturated te-trahydrofuran(THF)or dibutyl ether solution gave y-butyro-lactone or butanol and butyl butyrate as major products with small amounts of undetermined compounds,respectively.Their yields were also affected by the addition of Cu(Ⅱ)or Sn(Ⅱ)salts.     

Nucleotide hydrolysis in the presence of μ-hydroxo-bridged-cobalt(III) complexes

Abstract

Two cobalt(III) complexes with tridentate ligands, the acyclic diethylenetriamine and macrocyclic 1,4,7-triazacyclononane, were examined as potential catalysts for the hydrolysis of adenosine 5′-triphosphate (ATP). Studies were performed primarily at pH 4.5, where the two complexes were in the binuclear di-μ-hydroxo forms. For both complexes, a rapid initial hydrolysis with first order dependence on the concentration of ATP was observed, k_obs of approximately 0.20 min^?1, followed by very slow hydrolysis. Deuterium isotope studies done in D₂O showed a normal isotope effect with k_H/k_D = 1.8. Spectral investigations and ⁵⁹Co NMR studies indicated that the biphasic nature of the hydrolysis reaction may be due to the formation of a complex in which inorganic phosphate is coordinated to the cobalt, effectively poisoning the catalyst.     

Stereochemistry of the coupling step in photo-S_(RN) 1 reaction

The photo-S_(RN) 1 reaction of (+)-camphor and aryl halides was investigated in order toestimate the stereochemistry of the coupling step of aryl radicals with a nucleophile. The ratio of endo toexo products determined by ~1H NMR and CD spectra was found to be 99:1. MNDO calculationsof the orbital parameters showed a favorable one-sided overlap of the enolate ion with the SOMO of arylradical. In addition, fragmentation of (ArX)~- was found to be related to the energy of SOMO of(ArX)~-.     

Chemical Studies on the Glycosides in the Leaves of Oplopanax Elatus Nakai(Ⅳ)

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In situ study of the breakout crystallization in the poly(butadiene)-block-poly(ε-caprolactone) thin film

Despite its wide occurrence in soft confined block co-polymers, breakout crystallization remains poorly understood and is difficult to control. In this work, thin films of cylinder-forming poly(butadiene)-block-poly(ε-caprolactone) (PB-b-PCL) diblock co-polymers, with PCL being the minority block, have been chosen as the study subject. We demonstrate a new route to study the breakout crystallization by obtaining the microphase separation structure within terraced lamellae first and then in situ tracking down the lamellar coalescence, resulting from the development of the crystal growth front. We find that the crystal growth front has sucked materials from the surrounding amorphous lamellae, which lead to the decrease of the lamellar zones and coalescence of the microphase separation structure. Dividing the breakout crystallization into parallel breakout and vertical breakout, we illustrate that it is the crystallization-driven molecular diffusion that make the molecules overcome the topography constraint and grow into large-scale spherulite. Moreover, the results show that the polymer microphase separation structure has a significant influence on the crystal nucleation and greatly retarded the crystal growth rate. With a well-designed microphase separation structure within terraces and an easily tunable atomic force microscopy in situ imaging technique, an intensive study of the breakout crystallization and concomitant microdomain coalescence has been offered.     

Studies of the Intramolecular Aromatic-ring Stacking Interactions in the Ternary Platinum(Ⅱ) Complexes

The stability constants of some ternary mixed-ligand complexes, Pt(Phen)(CA) , where Phen=1,10-phenanthroline and CA- =carboxylate, were determined by means of potentiometric pH titration in aqueous solutions(I=0.1 mol/L, KNO3; 25 ℃), and the stability of them was compared with that of the corresponding binary complexes. It was revealed that the ternary complexes containing phenylalkane carboxylates ligands(PCA-) are much more stable than those formed with formate and acetate. The results indicate that there exist the intramolecular aromatic-ring interactions between the phenanthroline ring of Phen and the phenyl moiety of ligand PCA- in the ternary mixed-ligand Pt(Phen)(PCA)- complexes. The extent of the stacking interactions, which depends on the number of methylene groups between the phenyl moieties and the coordinated phenylalkane carboxylate groups, was calculated. The best-fitted stack was obtained for the complexes with 2-phenylacetate and 3-phenylpropionate as the ligands.     

Reactivity of thio (amino) derivatives of the ω-(4-hydroxyaryl)alkyl type in radical reactions

The enthalpies, activation energies, and rate constants of the reactions of thio (amino) alkylphenols of different structures were calculated and compared with those of the reactions of alkyl-substituted phenols, alkoxyl and alkyl radicals, hydroperoxides, and nitrogen dioxide, as well as the reactions of phenoxyl radicals with molecules of the substrate being oxidized. The calculation was performed by the intersecting parabolas method using O-H bond energy data for phenols. The correlation between the molecular structure of the thio (amino) alkylphenols and their reactivity in radical reactions is considered.     

Characterization of the bis(β-diimino-tetracyano-pyrrolizinido)-metal(II) complexes incorporated in polymeric matrices

The bis(-diimino-tetracyano-pyrrolizinido)-Cu(II) complex (CuL₂) has been incorporated in polystyrene (0.28% w/w), by evaporating tetrahydrofuran solutions either at room temperature (a) or at 100°C (b). From IR and UV-vis measurements and optical microscopy on the resulting films (a orb, thickness 50 m) it is concluded that CuL₂ is present as a concentrated (C10^–1 M) THF solution ina and as small solid particles (diameter <1 m) inb. The difference in colour of the films (dark bluea, light blueb), due to the different physical state of CuL₂ in the matrix, is expected, and has been preliminarily shown using similar films based on NiL₂, to be useful for sensing organic vapours in the atmosphere.