Zusammenhang zwischen den K α-Satelliten-Linien und den Röntgenübergängen vom Typ K 1 L 1→L 2 bei den Elementen Neon,Natrium, Magnesium,Aluminium und Silizium

Zusammenfassung Für die Elemente Neon, Natrium, Magnesium, Aluminium und Silizium werden mit einem quantenmechanischen Variationsverfahren unter Verwendung einer minimalen STF-Funktionenbasis Röntgenübergänge vom Typ K ¹L¹L² berechnet und den K -Satellit-Linien , , ₃, ₃ and ₄ zugeordnet.

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Relation between K -Satellits and X-ray-transitions of the type K ¹ L ¹L ² for Ne, Na, Mg, Al and Si

STF-Calculations are reported for X-ray-transitions of the type K ¹L¹L² for Ne, Na, Mg, Al and Si. It is shown that these transitions are correlated with the K -satellits , , ₃, ₃ and ₄.

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Die Wellenfunktionen können auf Anfrage zur Verfügung gestellt werden.     

Plutonium and americium in sediment samples along the Romanian sector of the Danube river and the Black Sea coast

The concentrations of²³⁸Pu,^239,240Pu and²⁴¹Am were determined in eight sediment samples, collected from the bed of the Romanian sector of the Danube river and the Black Sea coast during 1994 and 1995. Fusion with potassium carbonate was used to achieve complete dissolution of the samples. Tracers,²⁴²Pu and²⁴³Am, were added and the separation of plutonium from americium, uranium and thorium was performed by anion exchange. Americium was separated from uranium in two steps, using a conventional anion exchange resin and an extraction chromatographic resin for transuranics. After electrodeposition on stainless steel discs the nuclides were counted with -spectrometry with -PIPS detectors. The total plutonium concentrations obtained by this method were compared with the acid leachable plutonium concentrations reported for the same samples in a previous paper.     

Isomer yield ratios and cross sections for110(4.9 h)In/110(69 min)In and108(58 min) In/108(39.6 min)In produced by alpha reactions on silver

This paper reports the determination of absolute excitation functions and cross section ratios for the production of 110(4.9 h)/110(69 min) In and^{108(58 min)/108(39.6 min)}In in reactions of -particles with natural silver. Target stack foils of silver were bombarded with the 55.0 MeV -particle, beam available at the Buenos Aires synchrocyclotron. The -spectrometry was used for the identification and for the determination of the absolute activity of^{110(4.9 h)}In and^{110(69 min)}In from¹⁰⁷Ag/, n/ and¹⁰⁹Ag/, 3n/ reactions and of^{108(58 min)}In and^{108(39.6 min)}In from¹⁰⁷Ag/, 3n/ and¹⁰⁹Ag/, 5n/ reactions by means of Ge intrinsic detector.This work has been sponsored by the Subsecretaria de Ciencia y Tecnología Argentina.     

Structure of N,N-disubstituted α,β-unsaturated α-amino aldehydes

Study of the IR and¹H and¹³C NMR spectra of N,N-disubstituted ,-unsaturated -amino aldehydes showed that in the nature of the electron density distribution these compounds occupy an intermediate position between -unsubstituted amino olefins and ,-unsubstituted aldehydes, being significantly closer to the latter.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2031–2034, September, 1991.     

Procedures to define Pu isotopic ratios characterizing a contaminated area in Palomares (Spain)

Plutonium isotopic ratios have been calculated in soils contaminated by the Palomares accident which occurred in 1966 (Almería, Southeastem Spain). Contrasted techniques have been used to determine the radionuclide activities:²³⁸Pu and^238+240Pu were analysed by -spectrometry prior purification on anion-exchange resins, the ratio²³⁹Pu/²⁴⁰Pu was estimated by -spectra deconvolution and²⁴¹Pu was directly measured by liquid scintillation counting and indirectly through quantification of in-grown²⁴¹Am from aged plutonium discs. The mean activity ratios²³⁸Pu/²³⁹Pu,²³⁹Pu/²⁴⁰Pu,²⁴¹Pu/²³⁹Pu, backdated to 1966, were 0.027±0.002 (1), 4.5±0.2 (1) and 8.2±0.8 (1), respectively, characterizing the accident of Palomares as the source term of the measured plutonium.     

Determination of Np,Pu and Am in high level radioactive waste with extraction-liquid scintillation counting

A new method for the determination of transuranium elements, Np, Pu and Am with extraction-liquid scintillation counting has been studied systematically. Procedures for the separation of Pu and Am by HDEHP-TRPO extraction and for the separation of Np by TTA-TiOA extraction have been developed, by which the recovery of Np, Pu and Am is 97%, 99% and 99%, respectively, and the decontamination factors for the major fission products (⁹⁰Sr,¹³⁷Cs etc.) are 10⁴–10⁶. Pulse shape discrimination (PSD) technique has been introduced to liquid scintillation counting, by which the counting efficiency of -activity is >99% and the rejection of -counts is >99.95%. This new method, combining extraction and pulse shape discrimination with liquid scintillation technique, has been successfully applied to the assay of Np, Pu and Am in high level radioactive waste.     

Steroid compounds of marine sponges. VII. Preparation of derivatives of sokotrasterol and halistanol sulfates and structure-activity interrelationships among these compounds

Five new sulfated derivatives of sokotrasterol and halistanol have been obtained: 24-nor-5-cholane-2,3,6,23-tetraol 2,3,6-tri(sodium sulfate); 24-nor-5-cholane-2,3,6,23-tetraol 2,3,6-tri(sodium sulfate) 23-palmitate; 24,25-dimethyl-5-cholestane-2,3,6-triol 3-(sodium sulfate); 24,25-dimethyl-5-cholestane-2,3,6-triol 6-(sodium sulfate); and 24,25-dimethyl-5-cholestane-2,3,6-triol 2,6-di(sodium sulfate). The inhibiting and membranolytic properties of the polysulfated steroids from sponges and their derivatives have been studied. It has been shown that physiological activity in this series of compounds depends on biphilicity.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 441–445, July–August, 1986.     

1H-NMR Investigation of the Binding of 2-Methylnaphthalene to α-Cyclodextrin in D2O Solutions

As -cyclodextrin (-CD) was added to D₂Osolutions of 2-methylnaphthalene, its proton signals shifted to lower fieldsat low concentrations of -CD. At 2.0 × 10^-2 moldm^-3 of -CD, however, a reverse, higher-field shift wasobserved for the H-8 signal, indicating the formation of 1 : 1 and 2 : 1-CD–2-methylnaphthalene inclusion complexes. Intrinsic chemicalshift differences of all the protons in 2-methylnaphthalene have beenevaluated for both the 1 : 1 and the 2 : 1-CD–2-methylnaphthalene inclusion complexes. These intrinsicchemical shift differences suggest that the first -CD molecule has noselectivity in accommodating one end of uncomplexed 2-methylnaphthalene;-CD binds to a methyl group, as well as a naphthalene ring-end havingno methyl group, to form the 1 : 1 inclusion complex, resulting in theformation of two kinds of 1 : 1 complexes.     

Chemical treatment of US Department of Energy high level and low level waste to obtain a pure radiochemical fraction for determination of californium alpha-decay content

We have developed a chemical separation technique that allows the radiochemical determination of the californium -decay content in Department of Energy (DOE) high level wastes from the Hanford and Savannah River sites. The chemical separation technique uses a series of column extraction chromatography steps that use Eichrom Industries' lanthanide and actinide +3 oxidation state selective Ln-resin^® and the transuranic selective +4 oxidation state TRU-resin^® to obtain intermediate product phases in dilute nitric acid. The technique has been demonstrated on three types of authentic DOE high and low level waste samples. We obtain discrimination from Pu -activity by a factor of over 200 and from ²⁴⁴Cm -activity by a factor approaching 1700. Californium recoveries are measured by addition of a ²⁴⁹Cf spike and are in the range of 50% to 90% in the synthetic samples and are in the range of 1.4% to 48% for the authentic DOE waste samples.     

Enthalpy of solution of carbohydrates using a modified differential scanning calorimeter

A differential scanning calorimeter (DSC) was modified for the determination of enthalpies of solution. The measurements were performed on aqueous solutions of the deoxy- and fluoro-deoxy derivatives of D-glucopyranose (Glu) where the OH group on the C1, C2, C3, and C6 is replaced by H (1HGlu, 2HGlu, 3HGlu, and 6HGlu) and by F (1FGlu, 2FGlu, 3FGlu, and 6FGlu), 4-deoxy 4-fluoro--D-glucopyranoside (4FGlu), 1-methoxy--D-glucopyranoside (MeOGlu), 1-phenoxy--D-glucopyranoside (PheOGlu), D-mannopyranose (Man), and 3-methoxy--D-glucopyranoside (3MeOGlu), at 15.1, 25.0, 35.0, and 45.1°C. The enthalpies of solution _sH⁰(T) ranged from 1.00±0.25 kJ-mol^–1 for 6HGlu at 15.1°C to 20.4±1.4 for PhOGlu at 45.1°C and were in good agreement with literature values for Man, Glu, MeOGlu, and 3MeOGlu at 25.0 and 35.0°C and for MeOMan and 2HGlu at 35.0°C. _sH⁰(T) for the derivatives were then extrapolated up to the melting temperature T_m and compared with their enthalpies of fusion, _fH also determined from DSC measurements. If the agreement between _sH⁰(T_m) and _fH was within the 95% confidence level, then it was concluded that intermolecular interactions between the carbohydrate molecules in the liquid phase were the same as between the carbohydrate and water molecules in the solution phase. This agreement was observed for aqueous solutions of Man, Glu, MeOGlu, 3HGlu, 3FGlu, and 6FGlu.     

Substrate and Positional Selectivity in Electrophilic Substitution Reactions of Pyrrole, Furan, Thiophene, and Selenophene Derivatives

The relative reactivity (substrate selectivity) of five-membered heterocycles on electrophilic substitution (pyrrole >> furan > selenophene > thiophene) and their positional selectivity (furan > selenophene thiophene > pyrrole) are not consistent. The indicated differences in positional selectivity ( : ratios) of the parent heterocycles show up essentially in orientation on electrophilic substitution reactions of their derivatives and the corresponding benzannelated systems. It was shown that the positional selectivity was reduced in a sequence corresponding to the change in relative stability of the onium states of the elements (O⁺ < Se⁺ S⁺ < N⁺) and reflects the predominant role of the heteroatoms in stabilizing the -complexes formed on -substitution, in which the positive charge is distributed between the heteroatom and one -carbon atom (in -isom ers four atoms of the ring participate in delocalization of the charge). This interpretation was confirmed by quantum-chemical calculations carried out by the RHF/6-31G(d), MP2/6-31G(d)//RHF(6)-31G(d), and B3LYP/6-31G(d) ab initio methods.     

The synthesis of vinyl naphthalenes with fluorinated side chains

Summary Methods for the synthesis of -fluoro--vinyl naphthalene and -difluoromethyl--vinylnaphthalene were developed.     

Synthesis of bacterial antigenic polysaccharides and their fragments V. Use of 1,2-o-isopropylidene-4,6-O-ethylidene-α-D-galactopyranose for the synthesis of oligosaccharides with 3-o-substituted galactopyranose residue

Conclusions Trisaccharide-D-glucopyranosyl-(14)--L-rhamnopyranosyl-(1 3)-D-galactose was synthesized by using, 2-O-isopropylidene-4,6-O-ethylidene--D-galactopyranose for producing 1 3-rhamnosylgalactose, linkage.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1609–1613, July, 1977.     

Zur Stereoisomerie der 2,6-Dichlor-4-methoxyheptane

2,6-Dichloro-4-methoxy-heptanes may exist as 2 optical active isomers and 2 meso compounds. By double addition of ,-dichloro-dimethylether to propene a mixture of these stereoisomers was obtained. They were separated by HPLC. Using¹H- and¹³C-NMR-spectroscopy their configuration could be established.

     

A robust procedure for the determination of plutonium and americium in seawater

A new procedure for the analysis of Pu and Am in large water samples is presented. In this procedure, the actinides are first preconcentrated from 200 liter water samples with combined MnO₂ and Fe(OH)₃ co-precipitation. Pu and Am are then separated from the large amount of Mn by performing a second precipitation of Fe(OH)₃ at pH 6. The final separation of Pu and Am from interfering elements and from each other is achieved with the use of a single extraction chromatographic column of TRU-ResinÔ. The -activities are then determined using -spectrometry after source preparation by CeF₃ micro co-precipitation. The procedure described is faster, simpler, more robust and gives higher chemical yields then procedures normally used for routine analysis of Pu and Am. The chemical yields of Pu and Am, when analysing 200 liter sea water samples, are between 80-85%.     

Analysis of kinetic data by Johnson-Mehl equation

Johnson-Mehl equation is written as d/dt=k ⁿ t ^n–1 (1–) where is the degree of reaction,t time andn a constant. Use of this equation in kinetic analysis present problems because of the presence of a t term on the right hand side. The equation is not a true kinetic equation andk is not a true rate constant.This paper presents a brief discussion on the use of this equation as such or in a modified form and also indicates the proper procedure for evaluating kinetic parameters correctly. Some experimental data on the reduction of Fe₂O₃ to Fe₃O₄ have been used to test the mathematical procedure proposed. This reaction is known to follow the typical trend described by Johnson-Mehl equation.

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Zusammenfassung Die Johnson-Mehl-Beziehung lautet:d/dt=k ⁿ t ^n–1(1–) mit der Reaktionskoordinate, der Zeitt und der Konstanten. Eine Anwendung dieser Gleichung in der kinetischen Analyse verursacht Probleme, da auf der rechten Seite der Gleichung ein t-haltiger Ausdruck steht. Die Gleichung ist keine wirkliche kinetische Gleichung undk ist keine wahre Geschwindigkeitskonstante.Diese Arbeit beschreibt eine kurze Diskussion der Anwendung dieser Gleichung in dieser oder einer modifizierten Form und beschreibt, wie korrekte kinetische Parameter erhalten werden können. Zum Testen des vorgeschlagenen mathematischen Verfahrens wurden einige experimentelle Daten der Reduktion von Fe₂O₃ zu Fe₃O₄ benutz. Diese Reaktion ist bekannt, dem typischen, durch die Johnson-Mehl-Gleichung beschriebenem Trend zu folgen.

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Dr. S. B. Sarkar wishes to acknowledge the financial support of the Commonwealth Commission (U.K.) and the experimental facilities provided by the Imperial College of Science and Technology, London U.K.     

Laboratory standard for radionuclides in nuclear waste

A laboratory standard for the determination of long-lived radionuclides in nuclear waste has been prepared using concrete as matrix. It will be used to check sample preparation procedures, chemical separations and methods for the determination of nuclides, e.g., nuclear counting techniques or mass spectrometry. The material chosen was a fine-grained ready-to-use cement mixture, to which the following radionuclides were added:⁶⁰Co and¹³⁷Cs as -ray-emitting nuclides,⁹⁹Tc,⁹⁰Sr and⁵⁵Fe as radionuclides emitting pure -radiation or low-energy electrons, and²³³U,²³⁷Np,²³⁸Pu and²⁴¹Am as -emitters. Care was taken to attain a homogeneous distribution of the nuclides in the standard material. Pieces of about 1 g were formed as suitable and representative samples. Repeated analyses were carried out with the standard to check its homogeneity. The analytical procedures are described in brief. The pieces of the standard material have the same content of nuclides within ±5% at a 95% level of confidence.     

A general differential technique for the determination of parameters for d(α)/dt=f(α)A exp (−E/RT)

A general differential method is developed and described which determines the Arrhenius parameters, energy of activation and the preexponential factor, as functions of degree of conversion from sets of two or more experiments with differing thermal programs. (These experiments may be performed at any combination of isothermal, constant heating rate or other temperature programs.) The method tests to see whether or not the kinetics follow the equation,f()=(1–)ⁿ, and calculates the correct reaction order, n, when such an equation is applicable. The correct energy of activation,E, is determined as a function of both temperature and conversion. The correct preexponential term,A, is calculated for all cases described by equation, d()/dt=f () A exp(–E/RT), except for the autocatalytic case in whichf()=0)=0. Calculation of parameters for equations involving other functions forf() will be described in a subsequent paper.

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Zusammenfassung Es wurde ein allgemeines Differentialverfahren entwickelt und beschrieben, das die Arrheniusschen Parameter, namentlich die Aktivierungsenergie und den präexponentiellen Faktor, als Funktion des Umsetzungsgrades aus Angaben über zwei oder mehrere Experimente mit verschiedenen Temperaturprogrammen beschreibt. (Diese Experimente können mit beliebigen Kombinationen aus isothermen Temperaturprogrammen, solchen mit konstanter Aufheizgeschwindigkeit oder anderen Temperaturprogrammen durchgeführt werden.) Das Verfahren überprüft, ob die Kinetik durch die Gleichungf()=(1–)ⁿ beschrieben werden kann und berechnet die richtige Reaktionsordnungn, wenn eine solche Gleichung anwendbar ist. Die richtige Aktivierungsenergie E wird als Funktion von Temperatur und Umsatz bestimmt. Der richtige präexponentielle Ausdruck wird für alle beschriebenen Fälle mittels der Gleichung d()/dt=f()A exp (-E/RT) berechnet. Eine Ausnahme bildet der Fall Autokatalyse, wobeif(=0)=0 gilt. Die Berechnung der Parameter für Gleichungen mit anderen Funktionen fürf() wird in einem späteren Manuskript beschrieben.

     

Oligomerization of vinylic compounds on montmorillonite clay catalysts

Among the various solid acid catalysts used for oligomerisation, Montmorillonite K10 and filtrol clays are found to convert -methylstyrene and -phenylstyrene smoothly into indane derivatives in solvent-free liquid phase. However, in the presence of solvents like isoamylene, pentane and dichloromethane -methyl styrene reacts to give a linear dimer and trimer in different proportion.IPCL Communication No:265     

Unusual transformation of trimethylsilyloxyisoxazolidines initiated by the fluoride ion

It was found that opening of the isoxazolidine ring of 6a-isopropenyl-1/-trimethylsilyloxy-3, 3a,4,5,6,6a-hexahydro-(1H)-cyclopent[c]isoxazoles by the F^– ion initially gives an intermediate, a tertiary nitrosocompound detected by UV and NMR spectroscopy. Its transformation, finally, into ,-unsaturated aldoximes probably involves an unprecedented allylic migration of the nitroso group.Deceased.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 461–464, March, 1994.