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971.
Yong Wang Qiang Fu Qijun Li Gong Zhang Kaizhi Shen Yu‐Zhong Wang 《Journal of Polymer Science.Polymer Physics》2002,40(18):2086-2097
For a more complete understanding of the toughening mechanism of polypropylene (PP)/ethylene‐propylene‐diene rubber (EPDM) blends, dynamic packing injection molding was used to control the phase morphology and rubber particle orientation in the matrix. The relative impact strength of the blends increased at low EPDM contents, and then a definite ductile–brittle (D–B) transition was observed when the EPDM content reached 25 wt %, at which point blends should fail in the ductile mode with conventional molding. Wide‐angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) were used to investigate the shear‐induced crystal structure, morphology, orientation, and phase separation of the blends. WAXD results showed that the observed D–B transition took place mainly for a constant crystal structure (α form). Also, no remarkable changes in the crystallinity and melting point of PP were observed by DSC. The highly oriented and elongated rubber particles were seen via SEM at high EPDM contents. Our results suggest that Wu's criterion is no longer valid when dispersed rubber particles are elongated and oriented. The possible fracture mechanism is discussed on the basis of the stress concentration in a filler‐dispersed matrix. It can be concluded that not only the interparticle distance but also the stress fields around individual particles play an important role in polymer toughening. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2086–2097, 2002 相似文献
972.
973.
FuLinYAN AiXiaWANG ZhongJianJIA LeiHE 《中国化学快报》2003,14(12):1253-1254
A new isopropenyl benzofuran-type tetramer was isolated from the roots of ligularia stenocephala and its structure was established by spectroscopic methods. 相似文献
974.
Zhong‐Lu You 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(7):m339-m341
The title complex, [Cu(C11H14BrN2O)(N3)]n, is an interesting azide‐bridged polynuclear copper(II) compound. The CuII atom is five‐coordinated in a square‐pyramidal configuration, with one O and two N atoms of one Schiff base and one terminal N atom of a bridging azide ligand defining the basal plane, and another terminal N atom of another bridging azide ligand occupying the axial position. The {4‐bromo‐2‐[2‐(dimethylamino)ethyliminomethyl]phenolato}copper(II) moieties are linked by the bridging azide ligands, forming polymeric chains running along the b axis. Adjacent chains are further linked by weak Br⋯Br interactions into a sheet. 相似文献
975.
Hiroaki Aikawa Tero Kilpeläinen Nageswari Shanmugalingam Xiao Zhong 《Potential Analysis》2007,26(3):281-301
We establish a scale-invariant version of the boundary Harnack principle for p-harmonic functions in Euclidean C
1,1-domains and obtain estimates for the decay rates of positive p-harmonic functions vanishing on a segment of the boundary in terms of the distance to the boundary. We use these estimates
to study the behavior of conformal Martin kernel functions and positive p-superharmonic functions near the boundary of the domain.
H. A. was partially supported by Grant-in-Aid for (B) (2) (No. 15340046) Japan Society for the Promotion of Science. N. S.
was partially supported by NSF grant DMS-0355027. X. Z. was partially supported by the Taft foundation. 相似文献
976.
报道了以氯化钯作催化剂,区域选择性氧化9-烯丙基-1-氧代-4-氮杂双环(4.3.0)壬烷及10-烯丙基-1-氧代-4-氮杂双环(5.3.0)癸烷,制备了9-丙酮基-1-氧化-4-氮杂双环(4.3.0)壬烷及10-丙酮基-1-氧代-4-氮杂双环(5.3.0)癸烷。比较了不同催化条件和溶剂系统的反应收率,发现以PdCl2/对-苯醌为催化系统和以含水的DMF溶剂系统氧化收率最高。 相似文献
977.
978.
979.
A new method of preparing electrical conductive molybdenumoxide by thermal decomposition from hydrazine-containing molybdenum saltwas described.The process of the thermal decomposition of hydrazine-containing molybdemum salt was investigated by thermal analysis(TG and DTA)and the thermally decomposed product was studied by S.E.M.and chemicalanalysis.The result indicated that the molybdenum oxide obtained in thisway was electrical conductive. 相似文献
980.
Prof. Dr.-Ing. Dr.-Ing. E.h. K. Stephan M. Sc. L. -C. Zhong Dr.-Ing. P. Stephan 《Heat and Mass Transfer》1995,30(6):467-472
A model is presented that considers the influence of capillary pressure on the evaporation of a liquid film on a vertical that plate. The governing equations are derived and numerically integrated with a step-variable Runge-Kutta method. The numerical results are compared with the analytical solution from Nusselt's film condensation theory. The deviation from the Nusselt film theory become very prominent when the liquid film becomes thin enough. This can be attributed to the fact that the Nusselt film theory does not consider the influence of capillary pressure on the shape of the liquid film.Es wird ein Modell vorgestellt, das den Einfluß des Kapillardrucks auf die Verdampfung eines dünnen Flüssigkeitsfilms berücksichtigt, der entlang einer senkrechten Platte herabrieselt. Die maßgebenden Gleichungen werden abgeleitet und numerisch mit einem Runge-Kutta-Verfahren veränderlicher Schrittweite integriert. Die numerischen Ergebnisse werden mit denen der Nusseltschen Filmtheorie verglichen. Dabei ergeben sich beträchtliche Abweichungen von dieser in den Bereichen, in denen der Flüssigkeitsfilm sehr dünn wird. Dies ist darauf zurückzuführen, daß die Nusseltsche Filmtheorie den Einfluß des Kapillardrucks auf die Filmkontur nicht berücksichtigt. 相似文献