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101.
Blends of polypropylene (PP) and ethylene-octene copolymers (EOC) were investigated by transmission electron microscopy (TEM) and by differential scanning calorimetry (DSC). The EOC contained 28, 37, 40 or 52 wt% of octene. Only the 50/50 PP/EOC ratio was used for all blends. None of the blends was fully miscible, there was always two-phase morphology. TEM observation followed by image analysis by ImageJ software revealed that the largest particles were in blend containing EOC-28 and the smallest were in blend with EOC-52. The coarsening rate at 200 °C was evaluated by TEM. The glass transition temperature (Tg) shift indicated partial miscibility. Partial miscibility was then confirmed by direct observation of bright PP lamellae in EOC dark phase. 相似文献
102.
Klára Melánová Ludvík Beneš Vítězslav Zima Jan Svoboda Miroslava Trchová Jiří Dybal 《Journal of inclusion phenomena and macrocyclic chemistry》2007,58(1-2):95-101
Intercalation compounds of α-Zr(HPO4)2 · H2O with 1,2-alkanediols (from C3 to C16) have been prepared by replacing 1-propanol in α-Zr(HPO4)2 · 2C3H7OH with the desired 1,2-alkanediols by a treatment in a microwave field. It was found that the intercalates contain 1.5 molecules
of diol per formula unit. The diol molecules are placed between the host layers in a bimolecular way with their aliphatic
chains tilted at an angle of 51°. The diol molecules are anchored in the interlayer space by H-bonds. A mixed intercalate,
containing 1,2-butanediol and 1,2-decanediol in a roughly equimolar ratio, is formed when the α-Zr(HPO4)2 · 2C3H7OH intercalate, suspended in a mixture of 1,2-butanediol and 1,2-decanediol, is exposed to microwave radiation. No new phase
containing both types of the guest molecules was observed when the 1-propanol intercalate, suspended in a mixture of 1-propanol
and 1,2-octanediol, is exposed to microwave radiation. 相似文献
103.
Uranium is determined via its 239U nuclide (74.0 keV, t = 23.5 min) in natural waters down to 0.03 ng U ml-1 after preconcentration with activated carbon and oxine; 30-min irradiation and counting times are used. No preconcentration is required for samples containing more than 4 ng U ml-1 with 10-min irradiation and counting times. Uranium in urine can be determined under a boron shield at the 5 ng ml-1 level after 30-min irradiation and counting. 相似文献
104.
Molecular-mechanics calculations for strain of carbenium ions are tested using Bentley's unified reactivity scale for bridgehead solvolysis as reference. Excellent correlations are obtained for solvolytic bridgehead reactivity with the calculated steric-energy difference (ΔEst) between substrate (R? H or R? OH) and cation (R+). After adjustment of appropriate force-field parameters, the approach is successfully extended to the rigid, but planar cations derived from structures 15 – 20 ; however, the general set of parameters cannot be applied to highly strained systems such as the cation formed from 17 . With all of the 18 sets of parameters tested, the 2-endo-norbornyl derivative 16 , is adequately correlated, while the exo isomer 15 exhibits enhanced reactivity by a factor of ca. 102 to 103. 相似文献
105.
106.
The longitudinal magnetoresistance of polycrystalline platinum wires has been measured in magnetic fields up to 45 kOe at liquid helium temperatures. The deviations from Kohler's rule found depend on the concentration of quenched-in vacancies, and are interpreted as due to the contribution of single vacancies in platinum to the small angle scattering of electrons. The small-angle scattering may also be responsible for the linear magnetoresistance of platinum in high magnetic fields. 相似文献
107.
108.
V. Svoboda 《Fresenius' Journal of Analytical Chemistry》1968,238(3):161-167
Zusammenfassung Zur Beurteilung von Photomaterial, das zur spektrographischen Analyse mit hoher Nachweisempfindlichkeit bestimmt ist, eignen sich die Parameter L
max und R
max. L
max ist für Verfahren ma\gebend, bei denen man eine hohe absolute Nachweisempfindlichkeit erreichen will, R
max für eine hohe Konzentrationsempfindlichkeit. Es wurden Formeln abgeleitet, nach denen man den Wert dieser Parameter berechnen kann, wenn die Konstanten der Kennlinie , , E
0und die AbhÄngigkeit der SchwÄrzungsfluktuationen von der SchwÄrzung bekannt sind. Nach dem vorgeschlagenen Verfahren wurden die Eigenschaften von acht Spektralplattensorten verglichen.
Summary The parameters L max and R max are proposed for testing photomaterials used for high sensitivity emission spectrography. For attaining highest absolute sensitivity the materials with high value of L max are to be applied, for highest concentration sensitivity the value of R max is decisive. Formulas for these parameters are derived, which are functions of characteristic curve constants , , E 0of the form of Siedentopfs' equation and of the slope of density fluctuation. According to the method proposed 8 different photomaterials have been tested.相似文献
109.
110.