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1.
An increase in the number of titration cycles results in a considerable decrease in HT and OT values, which in turn, brings about a decrease in the amount of desorbed hydrogen. This shows that water, being a product of titration reaction, is adsorbed on the oxidized surface of rhodium and represents a kinetic-diffusive barrier for hydrogen titration.
, HT OT, , , . , , , , , - .
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2.
It is probable that different phenomena attributed to mechanical stirring during the Belousov-Zhabotinskii (BZ) reaction are caused by atmospheric oxygen and, as far as our experiments show, they have nothing to do with dissipative structures or with the turbulence of the reacting mixture.
, , , -, .
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3.
Catalytic deactivation dynamics of zeolites in multicycle processes has been calculated. It has been revealed that in naphthalene sorption on NaX zeolites surface deactivation is predominant with its similarity criterion close to unity and a high fraction of deactivation. Calculated data for several multicycle processes are given.
. , NaX . .
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4.
Liquid phase oxidation of cycloalkane diheteroanalogs catalyzed by compounds of Cu2+, Ni2+, Co2+, Cr3+, Fe3+ has been studied. It has been established that these catalysts can be applied to intensify, oxidize and increase the selectivity of this process.
: Cu2, Ni2+, Co2+, Cr3+, Fe3+. .
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5.
The theoretical curves in the coordinates a vs. time for isothermal, and avs. temperature for non-isothermal experiments are calculated as functions of three kinetic parameters: activation energyE, pre-exponentical factorA and theg() function describing the mechanism of thermal decomposition of solids. The results show that conclusions not taking into consideration all three parameters can lead to information of little value concerning the mechanism of the decomposition and kinetic calculations. A correlation between non-isothermal and isothermal experiments, important for determination of the thermal stabilities of the compounds, is impossible without a knowledge of theg() function.
Zusammenfassung Theoretische Umsatzkurven gegent für isotherme bzw gegen Temperatur für nichtisotherme Versuchsführung wurden berechnet in Abhängigkeit von den drei kinetischen Parametern AktivierungsenergieE, PräexponentialfaktorA und derg()-Funktion, die den Mechanismus der Zersetzung von Festkörpern beschreibt. Die Ergebnisse zeigen, dass Schlussfolgerungen, die nicht alle drei Parameter berücksichtigen, zu, Ergebnissen von geringer Aussagekraft bezüglich des Zersetzungsmechanismus und der kinetischen Interpretation führen. Eine Korrelation nicht-isothermer und isothermer Experimente, die für die Bestimmung der thermischen Stabilität der Verbindungen wichtig ist, ist ohne Kenntnis der Funktiong() unmöglich.

- - : , - g(), . , , , . , g().
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6.
Investigations of the thermal stability of detonating fuse containing 10 g pentaerythrol tetranitrate (PETN) revealed that the cord burnt under unconfinement at 403 K. Under confinement in a steel pipe or copper tube there was a partial detonation at 403 K. In order to characterize the thermal stability of PETN and pyrotechnic composition used in fuse head of electric detonators differential thermal analysis (DTA) was used.The electric detonators of aluminium cell and copper cell were heated from ambient temperature to 373 K at an average rate of 0.4 deg/min. The rate of heating was increased gradually to 1.5 deg/min till explosion. The detonation temperature varied between 373 K and 375 K.The impact and friction sensitivity of detonating fuse was poor. There was no detonation when a 5 kg hammer was repeatedly hit over the fuse from a height of one metre. There was no detonation when the detonating fuse was rubbed by a blunt edge of steel plate till it was smashed.
Zusammenfassung Untersuchungen der thermischen Stabilität von Sprengschnuren mit 10 gm–1 PETN zeigten, daß die Schnur frei bei 403 K verbrennt. Unter Abschluß in einem Stahloder Kupferrohr tritt bei 403 K eine partielle Detonation auf. Zur Charakterisierung der thermischen Stabilität von PETN und von pyrotechnischen Mischungen, die in Zünderköpfen von elektrischen Sprengkapseln verwendet werden, wurde Differentialthermoanalyse (DTA) angewendet. Die elektrischen Sprengkapseln von Aluminium- und Kupferzellen wurden mit einer durchschnittlichen Aufheizgeschwindigkeit von 0.4 Grad/min von Raumtemperatur auf 373 K erhitzt. Die Aufheizgeschwindigkeit wurde bis zur Explosion allmählich auf 1,5 Grad/min erhöht. Die einzelnen Detonationen erfolgten bei einer Temperatur zwischen 373 und 375 K. Die Stoß- und Reibempfindlichkeit der Sprengschnur war gering. Bei einem mehrmaligen Einwirken eines 5 kg-Hammers aus einer Höhe von 1 m erfolgte keine Detonation. Bei Reiben mit der unscharfen Kante einer Stahlplatte bis zur Zerstörung erfolgte keine Detonation.

, 10 –1 PETN, , 403 , 403 . PETN , , . 373 0,4°/. 1,5°/ . 373 375 . . 5 1 . , .


The authors are indebted to the Director, Central Mining Research Station for giving permission to publish this paper. The views expressed in the paper are those of the authors and not necessarily of the institute which they belong to.  相似文献   

7.
General forms of the kinetic equations for the conversion of various hydrocarbons in reforming of multicomponent gasoline fractions on platinum/alumina catalysts have been confirmed experimentally by using a gradientless method.
.
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8.
Three new hydrazinium(1+) fluoro complexes, N2H5AsF6, (N2H5)2ZrF6 and (N2H5)2HfF6, were prepared and characterized by means of chemical analysis, IR and Raman spectroscopy and X-ray powder diffraction. Study of their thermal behaviour via TG, DTG and DTA measurements showed that they decompose in stages; the decomposition of N2H5AsF6 proceeded in two steps, through the intermediate NH4AsF6; (N2H5)2ZrF6. Decomposed in three steps, through (NH4)2ZrF6 and NH4ZrF5. The thermal decomposition of (N2H5)2HfF6 is more complex; in the first step (NH4)2HfF6 with some N2H5HfF5 was obtained, and in the second NH4HfF5. The intermediates were identified by means of chemical analysis and vibrational spectroscopy.
Zusammenfassung Die Hydrazinium(1+)-fluorokomplexe N2H5AsF6, (N2H5)2ZrF6 und (N2H5)2HfF6 wurden dargestellt und durch chemische Analyse, IR- und Ramanspektren sowie Röntgenbeugungsdiagramme charakterisiert. Die Untersuchung ihres thermischen Verhaltens durch simultane TG-DTG-DTA-Messungen zeigte, dass sie sich schrittweise zersetzen: N2H5AsF6 zersetzt sich in 2 Stufen mit NH4AsF6 als Zwischenprodukt; (N2H5)2ZrF6 zersetzt sich in 3 Stufen über (NH4)2ZrF6 und NH4ZrF5. Die thermische Zersetzung von (N2H5)2HfF6 ist komplizierter, der erste Schritt liefert (NH4)2HfF6 mit wenig N2H5HfF5, der zweite NH4HfF5. Die Zwischenprodukte wurden durch chemische Analyse und Schwingungsspektroskopie identifiziert.

N2H5AsF6, (N2H5)2ZrF6 (N2H5)2HfF6, - , ., , . , N2H5AsF6 NH4AsF6, (N2H5)2ZrF6 — (NH4)2ZrF6 NH4ZrF5. (N2H5)2HfF6 : (NH4)2HfF6 N2H5HfF5, NH4HfF5. .


We thank Miss B. Sedej for chemical analysis. The work was financed through the Research Community of Slovenia.  相似文献   

9.
A comparison of the properties of supported zirconium catalysts containing zirconium ions in different valence states in ethylene polymerization shows that an increase in the proportion of active centers involving Zr(III) ions results in a decreasing molecular weight of the polymer. The catalyst activity is practically unchanged.
, , . , , Zr(III) . .
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10.
The activity of modified Fe/Al2O3 catalysts in the hydrocondensation of CO has been studied in terms of the selectivity for light olefins and of repartition of the hydrocarbon products.
Fe/Al2O3 CO, .
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11.
Nonsteady state activity during the gas phase oxidation of ethanol in a simple flow reactor and its dependence on pretreatment and reaction conditions can be explained utilizing the previously presented model of possible surface vanadia phases on silica.
.
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12.
Chemical oscillatory behavior in the uncatalyzed bromate oxidation of hydroquinone and nitrophenols is reported. The reaction is strongly inhibited by stirring. Effect of one-electron redox couples (EZ catalysts) on the system is described.
. . - ( EZ) .
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13.
The nature of adsorbed sulfonium and phosphonate ylids on a new barium hydroxide catalyst (C-200) is analyzed by IR. The catalytic activity of C-200 in solid-liquid phase transfer conditions is explained by these IR studies.
(C-200) . C-200 - .
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14.
The amount of 1-alkene formed by the dehydration of 2-methyl-2-butanol with several metal oxide catalysts parallels the temperature dependence of acetate pyrolysis where the amount of 2-methyl-1-butene increases with increasing temperature.
1-, 2--2- , , 2--1- .
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15.
An increase of the reduction temperature of a Ni/CeO2 solid results in a continuous decrease of the catalytic activity toward C2H6 hydrogenolysis and of the quantity of adsorbed H2. O2 treatments with subsequent reduction at low temperature restore a part of the initial properties. This behavior, typical of a strong metal support interaction, is similar to that of Ni/TiO2, Ni/SiO2 and Ni/ZrO2 solids and shows that the SMSI phenomenon is general.
Ni/CeO2 C2H6 H2. . , (), Ni/TiO2, Ni/SiO2 Ni/ZrO2 , .
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16.
4,4-bismaleimidophenyl methane (BM) and 3,3-bismaleimidophenyl sulfone (BS) were blended in solution using weight ratios 31 (MS31), 21 (MS21), 11 (MS11), 12 (MS12) and 13 (MS13). Chain extended bismaleimide resins were also prepared by treating BS/BM with 4,4-diaminodiphenyl ether in molar ratios of 10.3 (BM-E and BS-E resins). These resins were also blended with bismaleimides and the curing characteristics were evaluated by differential scanning calorimetry. Increase in BM content in BMBS blends or increase in chain extended bismaleimide content in BM-EBS or BS-E BM blends resulted in a reduction of melting and curing temperatures. Indication about the extent of cross-linking was obtained from solubility measurements (in DMF) of isothermally cured resins (180 °C, lh and 220 °C, lh in an air oven). Thermogravimetric analysis of samples isothermally cured at 180 °C and 220 °C (lh each) was carried out in nitrogen atmosphere. Improvement in thermal stability of chain extended bismaleimides was observed on blending.
Zusammenfassung 4,4-Bismalimidophenyl-methan (BM) und 3,3-Bismalimidophenyl-sulfon (BS) wurden in Lösung in den Gewichtsverhältnissen 31 (MS31), 21 (MS21), 11 (MS11), 12 (MS12) und 13 (MS13) gemischt. Auch kettenpolymerisierten Bismalimid-Harze wurden durch Behandlung von BS/BM mit Diaminodiphenylether im Molverhältnis 10,3 dargestellt (BM-E- und BS-E-Harze). Die Kennwerte der Aushärtung von Mischungen dieser Harze mit den Bismalimiden wurden mittels DSC ermittelt. Eine Erhöhung des BM-Gehaltes in den BM BS-Mischungen oder des Gehaltes der BM-E BS oder BS-E-Mischungen an kettenpolymerisierten Bismalimiden führt zu einer Erniedrigung der Schmelz- und Aushärtetemperaturen. Hinweise über den Vernetzungsgrad wurden aus Löslichkeitsmessungen (in DMF) von Isotherm (je 1 Stunde bei 180 und 220 °C in Luft) gehärteten Harzen erhalten. Die thermogravimetrische Analyse der Isotherm bei 180 bzw. 220 °C 1 Stunde ausgehärteten Proben wurde in Stickstoffatmosphäre ausgeführt. Die thermische Stabilität der Bismalimide wird durch Verschneiden verbessert.

4,4-- () 3,3-- () 31 (MC 31), 21 (MC 21), 11 (MC 11), 12 (MC 12) 13 (MC13). - / 4,4- 10,3 ( - C-). - . - - - - , . ( 1 180 220°) . . - .


The financial assistance provided by Department of Science and Technology is gratefully acknowledged.  相似文献   

17.
X-ray diffraction studies of platinum-alumina catalysts in a high-temperature chamber have revealed that for the catalysts obtained by the reduction of preactivated samples, no complete reduction of platinum takes place.
, , , .
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18.
The thermal interaction of Kovdor apatite, calcite, dolomite and forsterite with calcium polyphosphate up to 1200 °C were studied by chemical, thermal (under dynamic and quasiisothermal and isobaric conditions), X-ray, electronmicroscopic and chromatographic methods. It was found that the accompanying minerals of apatite react with calcium polyphosphate at lower temperature in comparison with apatite, complicating the process of thermal defluorination of papatite.
Zusammenfassung Die thermische Wechselwirkung von Kovdor-Apatit, Calcit, Dolomit und Forsterit mit Calciumpolyphosphat bei Temperaturen bis 1200 °C wurde durch chemische, thermische (unter dynamischen, quasiisothermen und isobaren Bedingungen), röntgenographische, elektronenmikroskopische und chromatographische Methoden untersucht. Es wurde festgestellt, daß die Begleitminerale des Apatits im Vergleich zum Apatit selbst bei niedrigeren Temperaturen mit Calciumpolyphosphat reagieren und so den Prozeß der thermischen Entfluorierung von Apatit komplizieren.

, , 1200° , ( ), , - . , , .
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19.
Copper oxide is moderately active and selective in the oxidative dehydrogenation of n-butane. Selectivity to C4 olefin is almost constant in the range of 200–520°C. The apparent activation energy determined between 200 and 360°C was 18.8 kcal/mol, and 9.2 kcal/mol at higher temperatures.
-. C4 200–520°C. 200–360°C 18,8 /, 9,2 /.
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20.
The Arrhenius expression for reaction 1, CH3CH2COO2NO2CH3CH2COO2+NO2, has been determined to be k=2×1015 exp (–12800/T)·s–1. The free radical mechanism is the exclusive thermal decomposition mechanism of PPN. The main nitrogenous decomposition products of pure PPN are ethyl nitrate, nitrogen dioxide and methyl nitrate. In the presence of NO, ethyl nitrite is the major organitrogen product.
CH3CH2COO2NO2CH3CH2COO2+NO2 : k=2·1015exp (–12800/T) –1. () - . , . NO .
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