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31.
Thermal properties of cis-1,4-poly(butadiene), Europrene cis, were investigated by means of thermal analysis and complementary methods. Thermal analysis of polymer was carried out both in air and inert atmosphere with a derivatgraph, DSC and internal TG-FTIR coupling system as well as internal TG, DTA-MS coupling system. It was found that investigations in air atmosphere the method of the sample preparation ofcis-1,4-poly(butadiene) influences the results of thermal analysis, which is connected with the rate oxygen diffusion into the reaction zone. Taking into consideration both the method of the sample preparing and atmosphere of thermal studies, the values of activation energy of destruction of cis-1,4-poly(butadiene) were determined. Using TG-FTIR and TG-MS methods, some products of thermal destruction of elastomer were determined.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
32.
The equilibrium of the reaction Cu2++Cu?2 Cu+ has been investigated in cone. solutions of Ca(ClO4)2. The apparent equilibrium constants of this reaction and the formal potentials of the Cu2+/Cu+, Cu2+/Cu and Cu+/Cu redox systems were determined. From these data the hydration numbers of the Cu2+ and Cu+ ions were estimated and the scheme of the reaction studied was proposed and discussed. In addition the equilibrium constants of the reaction Cu2++Cu(Hg)?2 Cu+ were calculated and discussed. 相似文献
33.
Effect of mineral fillers on thermal properties and flammability ofcis-1,4-polyisoprene vulcanizates
The effect of mineral fillers such as Ultrasil VN-3, Ze?O?Sil P-45, Aerosil 200, Frantex 8, Kaolin and precipitated calcium carbonate on the thermal properties sulphur vulcanizates ofcis-1,4-polyisoprene were studied by means of thermal analysis. It was found that the addition of a mineral filler did not change the nature of the thermal processes in isoprene vulcanizates essentially, but it distinctly affected the positions of the peaks recorded in the DTA curves. The mineral fillers affected the temperatures and rates of degradation and destruction of polyisoprene cross-linked with sulphur. The presence of a mineral filler brought about a decrease in the flammability ofcis-1,4-polyisoprene sulphur vulcanizates. 相似文献
34.
T. Kleps M. Piaskiewicz W. Parasiewicz L. Ślusarski 《Journal of Thermal Analysis and Calorimetry》1997,49(1):351-359
An effect of a cyclic low molecular-weight polymertrans-polyoctenamer rubber (TOR) on the thermal stability of diene rubbers and their vulcanizates was investigated. The investigation was carried out in the air and nitrogen atmospheres using thermogravimetry, DSC and simultaneous thermoanalytical methods. The thermal stability indexes:T
5,T
max and activation energy of degradation (E), as well asT
g andT
m values, have been determined.It was found thattrans-polyoctenamer (TOR) increases of the thermal stability indices of raw diene rubbers and their vulcanizates. The results show that the thermal degradation of diene rubbers occurred at higher temperature if they were blended with TOR. In our opinion, intermolecular structures formed between the cyclic low-molecular weight polymer and some linear rubber molecules may be the reason for the higher thermal stability of these rubber blends.The work was supported by State Committee for Research, Poland. Grant No. 7.T08 E 032-08. 相似文献
35.
A contamination in a 3-manifold is an object interpolating between the contact structure and the lamination. Contaminations
seem to provide a link between 3-dimensional contact geometry and the classical topology of 3-manifolds, as described in a
separate paper (Oertel and Świa̧tkowski, Contact structures, σ-confoliations, and contaminations in 3-manifolds. arXiv math.GT/0307177).
In this article we deal with contaminations carried by branched surfaces, giving a sufficient condition for a branched surface
to carry a pure contamination. 相似文献
36.
A solution of 2-(octylsulphanyl)benzoic acid in 1,2-dichloroethane was used as a liquid membrane for selective pertraction
of Pb2+ cations. Transport processes were carried out in a multi-membrane hybrid system (MHS) consisting of two cation-exchange membranes
(CEM) and a flowing liquid membrane (FLM) in the following order: CEM | FLM | CEM. The liquid membrane phase was dehydrated
continuously using a pervaporation method (PV). The system was capable of transporting Pb2+ ions selectively from a multi-cation aqueous solution composed of Na+, K+, Ca2+, Mg2+, and Pb2+ nitrates. A comparative study of the carrier efficiency under various feed pH conditions was performed. It was found that
the carrier exhibited sufficient selectivity and transport efficiency under a broad range of operational conditions, with
a maximum transport rate of Pb2+ ions attaining the value of (1.09 ± 0.03) × 10−10 mol cm−2 s−1 and the selectivity coefficient of up to 40. 相似文献
37.
Agnieszka Skórska-Stania Magdalena Śliwa Kamil Musilek Kamil Kuca Josef Jampilek Robert Musiol Barbara J. Oleksyn Jiri Dohnal 《Structural chemistry》2010,21(3):495-501
The investigation of relationships between the molecular structure of the compounds capable to reactivate acetylcholinesterase
(AChE) inhibited by organophosphorus toxins, such as nerve agents and pesticides, is an important step toward synthesis of
more efficient antidota. In the present article, we describe the crystal structures of two new AChE reactivators, which are
bromides of (E)-1,4-bis(4-hydroxyiminomethylpyridinium)-but-2-ene (K075) and of 4,4′-bis(hydroxyiminomethyl)-1,1′-(1,4-phenylenedimethyl)-bispyridinium
(K114). Their molecular geometry and intermolecular interactions in the crystalline state are compared to those in the crystal
structures of the well-known AChE reactivators, obidoxime, and TMB-4. Inspection of hydrogen bonds and other short intermolecular
contacts in the crystalline AChE–obidoxime complex revealed their similarity to those observed in the crystal structures of
K075 and K114. 相似文献
38.
Renata Świsłocka Monika Kalinowska Wiesława Ferenc Jan Sarzyński Włodzimierz Lewandowski 《Central European Journal of Chemistry》2012,10(4):1095-1105
The aim of this work was to study the spectroscopic and magnetic properties of copper(II) o-, m-, p-aminobenzoates, o-, m-, p-methoxybenzoates and o-, m- and p-nitrobenzoates. The complexes were synthesized and their compositions were evaluated by elementary analysis. The infrared and Raman spectra for Cu(II) aminobenzoates, methoxybenzoates and nitrobenzoates were recorded and assigned. The obtained data were compared with those previously published for aminobenzoic, methoxybenzoic and nitrobenzoic acids and their sodium salts. The structures of Cu(II) o-, m-, p-aminobenzoates, o-, m-, p-methoxybenzoates and o-, m- and p-nitrobenzoates as well as the change in the electronic charges distribution caused by Cu(II) complex formation were discussed. 相似文献
39.
Ludomir Zommer Alexander Jablonski László Kotis Gyorgy Safran Miklós Menyhárd 《Surface science》2010,604(7-8):633-640
A multilayer sample (C (23.3 nm)/Ta (26.5 nm)/C (22.7 nm)/Si substrate) was submitted to AES depth profiling by Ar+ ions of energy 1 keV and angles of incidence of 72°, 78°, and 82°. The shapes of the as-measured depth profiles were strongly different emphasizing that the ion-bombardment conditions strongly affects the shapes of measured depth profiles. We simulated the depth profile measured at an angle of incidence of 72° by calculating the backscattering factor, applying attenuation lengths available in the literature, and simulating the ion-bombardment-induced specimen alteration with a TRIDYN simulation and a trial and error method. The good agreement between the calculated and measured depth profiles justified the method applied. 相似文献
40.
We present various versions of generalized Aleksandrov–Bakelman–Pucci (ABP) maximum principle for L
p
-viscosity solutions of fully nonlinear second-order elliptic and parabolic equations with possibly superlinear-growth gradient
terms and unbounded coefficients. We derive the results via the “iterated” comparison function method, which was introduced
in our previous paper (Koike and Święch in Nonlin. Diff. Eq. Appl. 11, 491–509, 2004) for fully nonlinear elliptic equations. Our results extend those of (Koike and Święch in Nonlin. Diff. Eq.
Appl. 11, 491–509, 2004) and (Fok in Comm. Partial Diff. Eq. 23(5–6), 967–983) in the elliptic case, and of (Crandall et al. in Indiana Univ. Math. J. 47(4), 1293–1326, 1998; Comm. Partial Diff. Eq. 25, 1997–2053, 2000; Wang in Comm. Pure Appl. Math. 45, 27–76, 1992) and (Crandall and Święch in Lecture Notes in Pure and Applied Mathematics, vol. 234. Dekker, New York, 2003)
in the parabolic case.
Dedicated to Hitoshi Ishii on the occasion of his 60th birthday. 相似文献