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1.
The cohydrolysis of-cyanoethyl- and-cyanopropylmethyldichlorosilanes with dimethyldichlorosilane has been studied and the optimum conditions ensuring the maximum yield of rings containing cyanoalhyl groups have been determined.B is(-cyanoethyl)hexamethylcyclotetrasiloxane,-cyanopropylpentamethylcyclotetrasiloxane, and bis(-cyanopropyl)hexamethylcyclotetrasiloxane have been obtained for the first time and characterized.  相似文献   

2.
Zusammenfassung Es wird vorgeschlagen, die Bezeichnungen weak-field-Methode bzw. strong-field-Methode durch (L)-Methode bzw. ()-Methode zu ersetzen.Nach einer kurzen Einführung in die ()-Methode wird mit den Mitteln der Gruppen-und Darstellungstheorie eine Formel abgeleitet, mit deren Hilfe man schnell Rasse und Multiplizität der Terme eines Komplexions in der ()-Methode angeben kann. Einige Spezialfälle dieser Formel und die systematische Bestimmung der ()-Funktionen werden erörtert.
It is suggested that the misleading designations weak field method and strong field method be replaced by (L) method and () method, respectively.Following a brief introduction to the () method an equation is derived by group theoretical means which leads to rapid classification of the () terms. Several special cases and short cuts are discussed as well as the systematic determination of the () functions.

Résumé Le remplacement des termes «méthode du champ faible» et «méthode du champ fort» par «méthode (L)» et «méthode ()» est proposé.Après une introduction dans la méthode () une formule est dérivée à l'aide de la théorie des groupes et des représentations, qui donne la représentation irréductible et la multiplicité des termes d'un ion complexe dans le cadre de la méthode (). Quelques cas spéciaux de cette formule et la détermination systématique des fonctions (/gG) sont discutés.


Ich danke Herrn Professor Dr. H. Hartmann für den Hinweis auf das vorliegende Problem und der Deutsehen Forschungsgemeinschaft für ein Stipendium.  相似文献   

3.
The catalytic oxidation of lower olefins has been studied. The effect of ozonized oxygen has been examined. The results show that the apparent activation energy decreases. The industrial importance of the phenomenon is pointed out.
. , . . .
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4.
Acetylenic - and -keto alcohols and acetals of acetylenic - and -keto alcohols and acetals of acetylenic - and -formyl alcohols undergo cyclization to -dihydropyrones and -dihydrofuranones under the influence of acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1471–1473, November, 1976.  相似文献   

5.
Summary Polymetallic solid solutions of the ethylenediaminetetracetic acid (EDTA) and six divalent metal ions exist in the range: MgMnCoZnNiCu(EDTA) · 6H2O where + + + + + =2, 01, 0,,2, 0, 1.This type of structure is characterized by the presence of two different octahedral carboxylate-bridged coordination sites forming infinite zig-zag chains. Visible and i.r. spectra and t.g.a. analysis show that there is occupational preference for the two coordination sites in the crystalline structure.Due to this preference, and also to the structural features, the heterobimetallic MM(EDTA) · 6H2O compounds constitute a structurally new class of materials which can be described as ordered alternating-heterobimetallic polymeric coordination complexes.  相似文献   

6.
Tosylation of -cyclodextrin in an aqueous alkaline solution gave two regiospecific isomers (2-monotosyl--cyclodextrin(1) and 6-monotosyl--cyclodextrin(2)), that could recognize and catalyze small sized guest molecules; 2-monotosyl--CD recognized small sized guest molecules more effectively than did 6-monotosyl--CD.  相似文献   

7.
Fluorescent active host labeled at the upper and lower rims of -cyclodextrin, namely, mono-3A-deoxy-3A-pyrenebutylamido-6X,Y-O-bis-pyrenebutylate-mono-altro--cyclodextrin (-3) has been synthesized as a chemosensor for steroidal guests using fluorescence spectra change upon a guest addition. The -3 shows monomer and excimer fluorescence, which results in an increase of the intensity of monomer and decrease of excimer fluorescence with a host–guest binding in the cyclodextrin cavity. The extent of monomer and excimer fluorescence variations of -3 was used as an indication for the sensing ability for the guests examined. The guest-induced fluorescence changes were measured for 10–7 M solutions of -3. The sensing parameters (Iex/I0ex and Imon/I0mono) were used to describe the sensing ability of -3. The values of Iex/I0ex describe that -3 shows less selectivity for guests than that of mono-3A-deoxy-3A-pyrenebutylamido-6X-O-mono-pyrenebutylate-mono-altro--cyclodextrin (-2), and the values of Imon/I0mono show that -3 shows higher sensitivity and selectivity than that of -2.  相似文献   

8.
    
Zusammenfassung -Spektren von Radionuklidmischungen sowie von neutronenaktivierten Proben von Blei und Aluminium wurden mit einem NaJ(Tl)--Spektrometer und in einigen Fällen mit einem Ge(Li)--Spektrometer aufgenommen. Die Mischspektren wurden durch Vergleich mit Standardspektren der einzelnen Radionuklide nach einem Least-Squares-Verfahren in ihre Komponenten zerlegt. Die Auswertung erfolgte auf einer Rechenmaschine IBM 360/75.Die -Spektren waren mit und ohne Spektrenstabilisator aufgenommen worden. Das Rechenprogramm hatte die Optionen Gainshift-Korrektur und Eingabe und Eliminierung überzähliger Standards. Die Ergebnisse der verschiedenen Kombinationen von Meß- und Auswertungsverfahren werden diskutiert. Zur übersichtlichen Beurteilung der Ergebnisse wird eine ideale mittlere Standardabweichung definiert, mit der die gefundenen Standardabweichungen verglichen werden.Die beschriebenen Analysen demonstrieren die Möglichkeiten und Grenzen der Simultanbestimmung mehrerer Radionuklide mit den in vorhergehenden Arbeiten von uns beschriebenen Rechenprogrammen.
Experiences with the least squares analysis of -ray Spectra of nuclide mixtures and the simultaneous determination of long-lived radionuclides in neutron-activated lead and aluminium
-Ray spectra from artificial mixtures of up to 17 various radionuclides as well as -ray spectra from neutron activated samples of lead and aluminium were recorded by NaI (Tl)- and Ge(Li)--ray spectrometers and analyzed by comparison with standard spectra of the composing radionuclides. The evaluation was carried out by a least squares procedure using an IBM-360/75 computer. Recording of the -ray spectra was done with and without digital spectrum stabilization. The evaluation program offered the optional subprograms Gainshift Correction and Input and Elimination of Supernumerary Standard Spectra. Results from the various combinations of these different recording and evaluating techniques are discussed. In order to have an independent reference figure for comparison and estimation of the results an ideal mean standard deviation has been defined. The examples presented show the applicabilities as well as the limitations of this procedure for the simultaneous determination of several radionuclides by means of the computer programs recently described by us.


Herrn Priv.-Doz. Dr. H. W. Nürnberg danken wir für die stete Förderung dieser Arbeit. Herrn W. Soyka und Herrn M. Rauschen danken wir für die Hilfe bei der Aufnahme der -Spektren. Herrn Hendess vom Zentralinstitut für Angewandte Mathematik der KFA Jülich danken wir für die Mitarbeit bei den Computerberechnungen.  相似文献   

9.
The possibilities were evaluated of nondestructive determination of silicon content in large-scale samples of coal /about 20–50 kg/, based on the spectrometry of prompt -radiation from processes /n, n /, E=1779 keV and /n, /, E=3539 keV and 4935 keV. The neutron sources were either241Am–Be or252Cf located additionally in D2O moderator. A Ge/Li/ detector was used for -radiation detection. In exposure times of up to 2 h, the detection limits of 1.3% and 0.9% and accuracies of silicon determination of 0.66% and 0.40% have been achieved in case of /n, / and /n, n / processes, respectively.  相似文献   

10.
Photon correlation spectroscopy has been used to study theaggregation processes of natural and some modified cyclodextrins (CDs) in diluted aqueoussolutions. -, -, and -CD form large, polydisperse aggregatesin water, although the aggregation capability is different depending on the macrocycle considered. -CD solutions filtered through 0.2~m give a single-modaldistribution of aggregates of 224 nm in size. The monomeric -CD can be isolated by filtering through 0.1 m. -CD displays a bimodaldistribution (monomer + aggregates) with both pore sizes. At the concentrations studied (0.012 M) the contribution in mass of the aggregates with both CDs isnegligible. -CD is much more persistent in its aggregation, even after sievingits solutions through 0.02 m filters, and time dependent. The aggregation displayed byCDs with partial substitution of the OH groups (Methyl--CD and Hydroxypropyl--CD) is much weaker, indicating the implication of the hydrophilic rims ofthe CDs in the process. High temperatures, addition of urea or electrolytes andionisation of the OH groups by raising the pH, prevent the aggregation.  相似文献   

11.
The phase equilibria in the total range of component concentrations in the V2O5-Cr2O3 system up to 1000 °C were studied by means of phase powder diffraction and DTA. Two compounds exist in the system: CrVO4, melting incongruently at 860±5 °C, and Cr2V4O13, which decomposes in the solid state at 640±5 °C to CrVO4(s) and V2O5(s). At 645±5 °C, CrVO4 and V2O5 form a eutectic mixture with the CrVO4 content not exceeding 2% mol.
Zusammenfassung Mittels DTA und Pulverdiffraktionsaufnahmen wurde das Phasengleichgewicht des Systems V2O5-Cr2O3 bis 1000 °C im gesamten Konzentrationsbereich untersucht. Innerhalb des Systemes existieren zwei Verbindungen: CrVO4 mit einem inkongruentem Schmelzpunkt bei 860±5 °C und Cr2V4O13, das sich in festem Zustand bei 640±5 °C in CrVO4(s) und V2O5(s) zersetzt. Bei 645±5 °C bilden CrVO4 und V2O5 ein eutektisches Gemisch mit einem maximalen CrVO4-Gehalt von 2 mol%.

DTA V25-Cr23 1000° . : CrVO4, 860±5° Cr2V4O13, 640±5° CrVO4 V2O5, 645±5° CrVO4, 2 %.
  相似文献   

12.
A new nuclear excitation process,99Tc (, )99mTc reaction, was applied for the first time to radioactivation analysis of technetium. Bremsstrahlung irradiation of99Tc samples gave the reaction product99mTc which emits -ray measurable with ease by a semiconductor detector. The production rate of99mTc per g99Tc was linearly correlated with the flux of bremsstrahlung. The detection limit of99Tc was estimated to be nanogram order (0.63 Bq99Tc) under the optimum irradiation condition. Possible interference by100Ru(, p)99mTc reaction was also studied, which could be discriminated from the (, ) reaction by simultaneously occurring98Ru (, p)97Ru reaction.  相似文献   

13.
Summary Short-range segmental motions of the amorphous phase of polyamide 66 were studied by means of spin probe radicals. In a dry sample the relaxation in the temperature range 366–426 with an activation energy 27.6 kJ/mol was found. In a sample containing traces of water two processes, and relaxations, with activation energies 47.0 kJ/mol and 22.0 kJ/mol, respectively, were found. relaxation was dominant in the higher temperature range (410–460 K) while relaxation was active at lower temperatures (365–410 K).
Zusammenfassung Die inneren, lokalen Drehbewegungen in den amorphen Bereichen des Polyamid 66 wurden mit Hilfe der Paramagnersondenmethode untersucht. Wasserfreies Polyamid 66 zeigt den-Relaxations-prozeß (die Aktivierungsenergie 27.6 kJ/Mol) im Temperaturbereich von 366 K bis 426 K, wasserhaltiges Polyamid 66 zeigt zwei Prozesse,- und-Relaxationen, deren Aktivierungsenergien 47.0 kJ/Mol und 22.0 kJ/Mol sind. Die-Relaxation dominiert in dem höheren Temperaturbereich (von 410 K bis 460 K) und die-Relaxation in dem niederen Temperaturbereich (von 365 K bis 410 K).
  相似文献   

14.
The reactions of 1, 1, 3-trichloro-1-propene and also 1, 1, 1-trichloro-2-propene with acetoacetic ester gave -(, -dichlorallyl)acetoacetic ester (I). In the reactions with aniline and o- and p-toluidines, the corresponding -(, -dichloroallyl)--arylamino-crotonic esters were produced, thermal cyclization of which gave 2-methyl-3-(, -dichloroallyl)-4-hydroxyquinoline (II) and its 6CH3- (III) and 8CH3- (IV) homologs. With phosphorus oxychloride, II–IV gave the corresponding 4-chloro-substituted quinolines (V–VII); with concentrated sulfuric acid, II–VII were converted into the corresponding -quinolinylpropionic acids VIII–XIII.For part XI, see [5].  相似文献   

15.
METRIAREZ- and -, two new derivatives of 5-mercapto-1,2,4-triazole with - and -resorcylic acids have been synthesized and their physicochemical and chelating properties determined. With metal ions havingp andd electrons they form water-soluble coloured chelates at L M molar ratios of 1 1 with Cu2+ and Pb2+ ( and ), Hg2+ and Zn2+ () and Cd2+, In3+ and Bi3+ () and 2 1 with Fe3+, Fe2+, Co2+ and Ni2+ ( and ) and Zn2+ (). The chelates are non-extractable by organic solvents. The stability constants of these complexes, as well as their spectrophotometric sensitivity and extinction coefficients were determined. Iron and zinc in multivitamin tablets were determined spectrophotometrically using the ligands.  相似文献   

16.
-Alumina was synthesized by thermal decomposition of aluminium(III) isopropoxide, and its properties were investigated. The change in its surface area with increasing calcination temperature resembled that of -alumina. Both aluminas had the same acid strength, and their activities in isomerization of 1-butene were the same. -Alumina as a support for molybdenum catalyst in the epoxidation of allyl alcohol also behavedin the same manner as -alumina. Thus -alumina has almost the same catalytic properties as -alumina.  相似文献   

17.
The predictive accuracy for estimating infinite dilution activity coefficients by a modification of the UNIFAC method wherein the group interaction parameters were based on only data (referred to as -based UNIFAC) has been studied. Estimates and measured values were compared for six prototypical solutes in a series of homologous n-alkanes, l-alcohols and alkanenitrile solvents. Despite the fact that the interaction parameters were derived using only data, this approach still gave serious errors due to several inherent problems in the original UNIFAC model. Its performance is sometimes even poorer than that of the original UNIFAC method. For example for nitromethane in alcohols and p-dioxane in nitriles values predicted by the -based UNIFAC are essentially zero. The large errors for these systems are most likely due to inaccurate interaction parameters in the -based UNIFAC method.  相似文献   

18.
Zusammenfassung Ringschluß von -bzw. -Phenyl--ferrocenyl-buttersäure liefert die homoannular überbrückten Ketone (- bzw. -Phenyl--ketotetramethylen)-ferrocen (VI, VII, XIV). Die Ermittlung der Absolutkonfiguration dieser Ketone gelang durch Korrelation des Asymmetriezentrums der optisch aktiven -Phenyl--ferrocenyl-buttersäure (deren Absolutkonfiguration primär bestimmt wurde) mit der Konfiguration des planar asymmetrischen Anteils in den optisch aktiven Ketonen.Die erhaltenen Ergebnisse waren auch mit der früher für (+)-1,2-(-Ketotetramethylen)-ferrocen (I) auf unabhängigem Weg ermittelten Konfiguration in Einklang, wie durch Messung des optischen Circulardichroismus erwiesen werden konnte: die rechtsdrehenden Enantiomeren besitzen die (R), die linksdrehenden (S)-Konfiguration.
Ring closure of - and -phenyl--ferrocenylbutyric acid yielded the corresponding homoannularily bridged ketones, (- and -phenyl--ketotetramethylene)-ferrocene (VI, VII, XIV), respectively. The absolute configuration of these ketones could be established by correlation of the asymmetric center of the optically active -phenyl--ferrocenylbutyric acid (whose absolute configuration was determined previously) with the configuration of the planar asymmetric part in the optically active ketones.The results obtained support the configuration reported earlier for (+)-1,2-(-ketotetramethylene)-ferrocene (I) and established by an independent route. The configurations could also be supported by use of optical circular dichroism, i. e., the dextrorotatory enantiomers have the (R)-configuration, the laevorotatory the (S)-configuration.


Mit 1 Abbildung

Über die Verwendung des Ausdruckes Ferrocen-Chiralität (bzw. Chiralitäts-Zentrum und Planar-Chiralität) vgl., Fußnote S. 266.

Vgl. hierzu die Fußnote auf S. 1066

3. Mitt. über Ferrocenasymmetrie, zugleich 24. Mitt. über Ferrocenderivate:H. Falk undK. Schlögl, Mh. Chem.96, 266 (1965).  相似文献   

19.
Summary Surface tension e of mercury in equilibrium with crystals (floating on its surface) of octacosane, 1-hexadecanol, 1-octadecanol, ethyl palmitate, benzophenone and azoxybenzene at 7° is almost equal to that at 23° (measured earlier); also the difference between the surface tension ( 0) of uncontaminated mercury and e (i. e., equilibrium surface pressure) is independent of temperature within the limits of the experimental error. This shows that the hypothesis making 0- e an analog of the vapor pressure of the solid is incorrect. The relation e= (=cohesion of the crystal,=thickness of the surface layer of mercury) is in agreement with the negligible temperature coefficient of e . The calculated is approximately 9 angstroems.
Zusammenfassung Die Oberflächenspannung e von Quecksilber im Gleichgewicht mit Kristallen (schwimmend auf der Oberfläche) von Octosane, 1-hexadecanol, 1-octodecanol, Äthylpalmitat, Benzophenon und Azoxylbenzol bei 7 °C ist nahezu gleich der bei23 °C gemessenen. Auch die Differenz der Oberflächenspannung von reinstem Quecksilber ( 0) und ( e), d. h. dem Gleichgewichtsobderflächendruck ist unabhängig von der Temperatur innerhalb der experimentellen Fehlergrenze. Dies zeigt, daß die Hypothese, nach der man 0- e in Analogie zum Dampfdruck des Festen betrachtet, unkorrekt ist. Die Beziehung e= (=Kohäsion des Kristalls,=Dicke des Oberflächenfilms auf Quecksilber) ist in Übereinstimmung mit dem vernachlässigbaren Temperaturkoefifzienten von e. Das berechnete beträgt ungefähr 9 Å.
  相似文献   

20.
The -radiolysis of Methyl Red solution in HCl medium at pH=2 has been studied along with energy transfer reaction brought about byF and hole centers of -irradiated NaCl. The G-values for degradation of the azo dye indicator by radiolysis and -irradiated salt were determined as 9·10–1 and 4.8·10–3, respectively. The kinetic rate constants (k) of degradation are evaluated as 2·10–5 rad–1 in the case of direct radiolysis, while for the irradiated salt it is 2·10–7 rad–1. The extent of degradation by direct -radiolysis is 100–200 times greater as compared to that by the -irradiated salt. The same mechanism is proposed for radiolysis as well as the reaction induced by -irradiated sodium chloride.  相似文献   

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