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1.
《Comptes Rendus de l'Academie des Sciences Series IIC Chemistry #》1999,327(14):1351-1354
Knowles and Sternberg gave the definition of the M integral relative to the dilatational symmetry in the elasticity domain. The path domain independence of this integral correspond to some very restricted applications. We propose to enlarge the field of application in defining for every type of transformation a modified path domain independent M integral. The demonstration that this conservation law is associate to the transformation is considered. 相似文献
2.
《European Polymer Journal》1987,23(1):1-5
A study of rheological properties in the molten state of two short glass fibre reinforced polyesters (polyethylene terephthalate and polybutylene terephthalate) was carried out, both in steady and dynamic flow. The results lead to information on the flow behaviour of these composite materials. Moreover, this study confirms the presence of fibre tied entanglements and shows the influence of the matrix. 相似文献
3.
《Comptes Rendus de l'Academie des Sciences Series IIC Chemistry #》1999,327(11):1197-1200
To evaluate the thickness of the layers of a Ti/TiAl3/Al system, experiments based on surface resistance measurements have been performed. The thickness of each layer is deduced from a comparison among calculated and measured values of resistance. We present here a solution for the simulation of surface resistance and the results obtained with this method on Ti/TiAl3/Al systems. 相似文献
4.
《Annales de Chimie Science des Materiaux》1999,24(3):233-240
The magnetic properties of titanium phosphates ATiP2O7 (A=Na,K,Rb), A2Ti2(PO4)3 (A=K,Rb), BaTi2(PO4)3 M g3Ti4P6O24 and titanium silicophosphates ATi3P6Si2O25 (A=K,Cs) have been investigated by magnetic susceptibility and electron spin resonance measurements. All the compounds are paramagnetic and the thermal variation of the susceptibility can be described with a Curie-Weiss law χm=χ0+ Cm/T−θp. The values of μeff per Ti+3 and the spectroscopic data obtained from the 77K E.P.R. spectra are discussed as a function of the structural data. 相似文献
5.
Résumé Les spectres d'absorption infrarouge de l'acétate de méthyle et de l'acétate de méthyle perdeutéré ont été étudiés de 300 à 4000 cm–1. La comparaison des spectres a permis l'attribution certaine des bandes de l'acétate de méthyle, en particulier de la bande observée vers 1245 cm–1 qui correspond à une vibration concernant la liaison C-O.
Summary The infrared absorption spectra of methyl acetate and the perdeuterated methyl acetate have been studied from 300 to 4000 cm–1. The comparison of the spectra has made it possible to attribute certain of the bands of methyl acetate, in particular the band observed around 1245 cm–1, which corresponds to a vibration involving the C-O bond.
Zusammenfassung Die Absorptionsspektren von Methylacetat der Zusammensetzung CH3COOCH3 und CD3COOCD3 im Infrarot wurden zwischen 300 und 4000 cm–1 untersucht. Der Vergleich dieser Spektren führte zur sicheren Zuordnung der Banden des Methylacetats, insbesondere der bei 1245 cm–1 gelegenen Bande, die der C-O-Bindung zugehört.相似文献
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7.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1978,34(10):965-966
A comparative study is made of i.r. and Raman spectra of p-toluidine rhombic single crystals in the 0–200 cm−1 range, at liquid helium temperature. No evidence of a phase transition up to room temperature has been found 相似文献
8.
《Annales de l'Institut Pasteur. Immunologie》1981,132(2):219-230
The authors describe a method for isolation of Toxoplasma gondii antigenic membrane components. Technical work is described into four points:
- 1.1) specific labelling of membrane proteins was realised by DD125ISA;
- 2.2) methacrylate microspheres were bound to unbroken toxoplasma membranes by the mean of an indirect technic with antibody molecules (double sandwich); these microspheres were used to modify the membrane density;
- 3.3) toxoplasmas bound to microspheres were broken by sonication;
- 4.4) microspheres fixed to membrane components were isolated by isopycnic ultracentrifugation on continuous sucrose gradient.
9.
《Comptes Rendus de l'Academie des Sciences Series IIC Chemistry #》1999,327(12):1215-1221
This note presents, in the framework of three-dimensional linear elastodynamics in the time domain, a method for evaluating sensitivities of integral functionals to crack shapes, based on the adjoint state approach and resulting in a sensitivity formula expressed in terms of surface integrals (on the external boundary and the crack surface) and contour integrals (involving the direct and adjoint stress intensity factor distributions on the crack front). This method is well-suited to boundary element treatments of e.g. crack reconstruction inverse problems. 相似文献
10.
《The Chemical Engineering Journal》1991,45(3):149-164
A recursive procedure for enumerating separation sequences involving columns with one or two feed streams and several sidestreams is presented in t 相似文献
11.
Résumé La méthode indiquée parKendall etFriedemann pour le dosage de l'alanine n'est nullement spécifique de cet acide aminé; les modifications queFürth et ses collaborateurs ont apporté à cette méthode dans le but de la rendre spécifique, n'ont atteint ce but que partiellement, et par des moyens compliqués.Le présent travail montre qu'il suffit d'ajouter à la solution des hydroxyacides provenant de la désamination des acides aminés, le dixième de son volume d'une solution d'acétate mercurique à 5% pour empêcher au cours del'oxydation ulterieure par le permanganate, toute production d'acétaldéhyde à partir de la sérine et de l'acide aspartique; dans ces conditions, l'acétaldéhyde formé ne provient plus que de l'alanine. La réaction colorimétrique donnée par l'acétaldéhyde avec le nitroprussiate de soude et la pipérazine, permet d'en faire le dosage spécifique en présence des autres aldéhydes fournis pas les autres acides aminés. Il est ainsi possible de doser l'alanine d'une façon rigoureusement spécifique en présence d'acides aminés quelconques. Cette méthode permet la détermination, à 5% près, de 2 mgr. et plus d'alanine.En modifiant les conditions d'oxydation par le permanganate (augmentation de la concentration en SO4Mn, et de la durée d'oxydation) et en supprimant l'addition d'acétate mercurique, on obtient une production quantitative d'acétaldéhyde à partir de l'ensemble alanine + sérine + acide aspartique; il est ainsi possible de doser la somme de ces trois acides aminés en présence d'acides aminés quelconques, et de déterminer, par conséquent, la teneur d'un mélange d'acides aminés quelconques en alanine d'une part et en l'ensemble sérine + acide aspartique de l'autre. Les chiffres obtenus correspondent à 95 à 97% de la teneur réelle en alanine, et à 93 à 95% de la teneur réelle en sérine + acide aspartique.
Summary The method given byKendall andFriedemann for the determination of alanine is by no means specific for this amino acid.Fürth and his co-workers introduced some modifications in order to make the method specific. The aim, however, was obtained but partially and by complicated means.It is shown in the paper present that it is sufficient to add to the solution of the hydroxy-acids formed by desamination of the amino-acids, one tenth of its volume of a 5% mercuric acetate solution, in order to inhibit the formation of acetaldehyde from serine and aspartic acid during the ultimate oxidation by permanganate. Acetaldehyde formed under those circumstances solely originates from alanine. The colour reaction which acetaldehyde gives with sodium nitroprussiate and piperazine, is specific. Thus, a colorimetric determination of acetaldehyde in presence of other aldehydes originating from the other amino-acids, is made possible. It ensues that a strictly specific determination of alanine in the presence of any other amino acid can be performed. This method allows to determine, at least, 2 mgs. of alanine, the limit of error being about 5%. By altering the conditions of the permanganate oxidation (i. e. by augmenting the concentration of manganous sulphate or by extending the time of oxidation) and by omitting the addition of mercuric acetate, acetaldehyde is formed quantitatively as a product of the sum of alanine + serine + aspartic acid. It is possible, in this way, to determine the sum of these three amino acids in presence of any other amino acids and to calculate therefrom the quantity of both alanine and the sum of serine + aspartic acid, contained in a mixture of whatsoever amino acids. The figures obtained represent 95–97% of the true alanine content, and 93–95% of the true content of serine + aspartic acid.
Zusammenfassung Die vonKendall undFriedemann für die Bestimmung des Alanins angegebene Methode ist für diese Aminosäure keineswegs spezifisch. Die Modifikationen, die vonFürth und seinen Mitarbeitern eingeführt wurden, um die Methode spezifisch zu gestalten, erreichen dieses Ziel nur teilweise und durch komplizierte Mittel.Die vorliegende Arbeit zeigt, daß es genügt, der Lösung der Oxysäuren, die bei der Desaminierung der Aminosäuren entstehen, ein Zehntel ihres Volumens an 5%iger Quecksilberacetatlösung zuzufügen, um die Entstehung von Acetaldehyd aus dem Serin und der Asparaginsäure bei der schließlichen Oxydation mit Permanganat zu verhindern. Der unter diesen Umständen gebildete Acetaldehyd entsteht lediglich aus dem Alanin. Die Farbreaktion, die der Acetaldehyd mit Nitroprussidnatrium und Piperazin gibt, ist spezifisch und ermöglicht eine kolorimetrische Bestimmung in Gegenwart anderer Aldehyde, die aus den anderen Aminosäuren entstehen. Es ist mithin eine streng spezifische Bestimmung des Alanins in Gegenwart irgendeiner anderen Aminosäure möglich. Diese Methode gestattet die Bestimmung von wenigstens 2 mg Alanin bei einer Fehlergrenze von ungefähr 5%. Wenn man die Bedingungen bei der Permanganatoxydation ändert (durch Erhöhen der Konzentration von MnSO4, bzw. der Oxydationsdauer) und das Zufügen von Quecksilberacetat unterläßt, erfolgt die Bildung des Acetaldehyds quantitativ, und zwar aus der Summe Alanin + Serin + Asparaginsäure; es ist auf diese Weise möglich, die Summe dieser drei Aminosäuren in Gegenwart beliebiger anderer Aminosäuren zu bestimmen und daraus den Gehalt eines Gemisches beliebiger Aminosäuren an Alanin einerseits und an der Summe Serin + Asparaginsäure andererseits zu bestimmen. Die erhaltenen Zahlen entsprechen 95 bis 97% des wahren Alaningehaltes und 93 bis 95% des wahren Gehaltes an Serin + Asparaginsäure.相似文献
12.
《European Polymer Journal》1985,21(12):1005-1011
The radiation initiated polymerization of methyl acrylate was investigated under precipitating conditions in n-hexane In 10 and 25% monomer solutions, the conversion curves are auto-accelerated and post-polymerization is observed in the dark. The initial rate of this post-polymerization steadily increases with the degree of conversion reached during irradiation, suggesting that trapped growing chains are responsible for the effect. The post-polymerization was followed at 23, 40 and 60°. From the results, it is concluded that chain termination is negligible under such conditions. The addition of methanol to the monomer solutions results in decreased rates and in a reduction of the extent of auto-acceleration. No influence of any “matrix effect” could be detected in these systems. 相似文献
13.
Jean -Pierre Labbé 《Mikrochimica acta》1962,50(1-2):283-288
Résumé L'auteur présente une nouvelle méthode microgravimétrique pour le germanium, utilisant la pesée du germanimolybdate de tétraphénylarsonium. Le facteur analytique estF
Ge=0,02137 pour le métal.
En l'honneur du ProfesseurF. Feigl, pour son 70e anniversaire. 相似文献
Summary A new method is described for the microgravimetric determination of germanium by means of the weight of the tetraphenylarsonium germanimolybdate. The gravimetric factor isF Ge=0.02137 for the metal.
Zusammenfassung Eine neue mikrogravimetrische Methode zur Bestimmung von Germanium als Tetraphenylarsonium-Germano(IV)-molybdat wird angegeben. Der Umrechnungsfaktor zur Ermittlung des Gehaltes an elementarem Germanium beträgt 0,02137.
En l'honneur du ProfesseurF. Feigl, pour son 70e anniversaire. 相似文献
14.
Using a hanging dropping mercury electrode (according to Vogel) the autliors find a better sensitivity of measurements in the determination of triphenyl tin acetate as fungicide residues on vegetable inatter. 相似文献
15.
《European Polymer Journal》1985,21(6):591-596
The thickening process for unsaturated polyester resin in styrene monomer and with magnesium oxide (MgO) has been evaluated by gel permeation chromatography (GPC). The GPC analysis n tetrahydrofuran (THF) shows that with time the distribution shifts towards higher molecular weight. This effect disappears when the products are analysed in a polar solvent. The process of thickening is attributed to the formation of reversible ionic association. The existence of strong ionic bonds in the final products is confirmed by the presence of a rubber-like plateau in dynamic mechanical properties. The effects of water and magnesium oxide concentrations are given. 相似文献
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Two compounds of sulphamide type:p-amino-benzene sulphonamide (I) and 3,4-dimethylisoxazol 5-sulphanylamide (II) were studied by combustion calorimetry and by differential scanning calorimetry (DSC).The enthalpies in solid state at 298,15 K of combustion, c
H
m
o
(I)=-2788,5±1,6 kJ mol–1, c
H
m
o
(II)=-5036±3,8 kJ mol–1 and of formation, f
H
m
o
(I)=-458,3±1,6 kJ mol–1, fH
m
o
(II)=-180,1±3,8 kJ mol–1 were determined.The thermal effects concerning the melting and phase transition of this compounds were also measured. 相似文献
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《The Chemical Engineering Journal》1992,48(2):119-127
The authors present the results of an experimental study on the crystallization of tetrahydrate sodium perborate in a fluidized bed. The influences of supersaturation, seed crystal size, temperature and solution velocity on the overall growth rate were examined. The overall dissolution rate determined under comparable hydrodynamical conditions for various seed crystal sizes and temperatures is also reported.The growth rate is not very sensitive to the variations in crystal size, the temperature and the hydrodynamical conditions, but it depends on the supersaturation and the presence of some soluble impurities.The comparison between growth and dissolution rates shows that under actual working conditions the diffusional mass transfer step is not the limiting step of the growth mechanism. 相似文献
20.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1986,42(8):919-925
The force constant matrix F of the pyrrole molecule has been determined on the basis of the experimental frequencies of C4H4NH and C4D4ND by an iterative consistency method. The force field obtained interprets quite well the vibrational spectra of pyrrole and its deuteroderivatives. The band assignments are discussed and compared to other published data. 相似文献