Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
The morphology of even-even nylons has been reexamined in order to determine whether crystallographic factors can exert a dominant influence on the morphology and growth behavior of polymeric spherulites. Directional solidification of these polyamides produces long oriented spherulites at zone velocities below ∼5 μm/m…
Emerging chick limb-buds at first grow only in length, not width. The growth parameters of limb mesoderm--cell shapes, distributions, division patterns and cleavage orientations--are incompatible with representations of this tissue as an elongating solid composed of proliferating but immobile cells. We observe that sa…
The morphological diversity in even-even nylons described in Paper I was found to be the result of crystallographic factors related to the high extent of hydrogen bonding. Among all spherulitic species in these polyamides, only positive spherulites crystallize in accordance with the phenomenological theory of Keith an…
Abstract X‐Ray diffraction orientation measurements have been made on a wide range of films blown from three high‐density polyethylenes, to determine more precisely the conditions which lead to the high‐stress crystallization type of orientation. The most extensive measurements relate to films from Hostalen GM 9955F;…
Magnetic properties and electrical conductivity of the YFe 2 O 4 single crystal were investigated. It was disclosed that YFe 2 O 4 is an antiferromagnet whose Néel point is 205 K, and the spin lies parallel to the hexagonal c axis. Below T N , the magnetization parallel to the c axis was not proportional to the magnet…
Abstract After X‐ray excitation of PbWO 4 /PbMoO 4 mixed single crystals at liquid nitrogen temperature two types of MoO ‐electron centres are observed by means of EPR. For low molybdenum concentration axial S 4 ‐symmetry centres are present, whereas in the case of crystals with high molybdenum content the centres und…
The paramagnetic susceptibility of potassium-tetracyanoquinodimethane (K-TCNQ) as a function of temperature is analyzed. K-TCNQ is considered to be in the strong to intermediate correlation regime of the Hubbard model. The magnetic properties are described in terms of a Heisenberg exchange Hamiltonian between localize…
The rheological behavior of PVC emulsion resin plastisols was investigated in steady shear flow. The shear rate dependence of the plastisol viscosity was influenced by (1) Brownian diffusion, (2) partial dissolution of the suspended resin, and (3) particle‐particle interactions. Partial dissolution of polymer from the…
Degradation of natural or man‐made polymers in supercritical acetone offers considerable advantages because sensitive products can be detected and secondary reactions largely suppressed. Cellulose and chitin serve as examples to demonstrate the conveint nature of this procedure.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTUse of terbium(III) fluorescence enhancement to selectively monitor DNA and RNA guanine residues and their alteration by chemical modificationDavid P. Ringer, Stuart Burchett, and Donald E. KizerCite this: Biochemistry 1978, 17, 22, 4818–4825Publication Date (Print):October…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and thermal decomposition of homoleptic tert-butyl lanthanide complexesAndrea L. Wayda and William J. EvansCite this: J. Am. Chem. Soc. 1978, 100, 22, 7119–7121Publication Date (Print):October 1, 1978Publication History Published online1 May 2002Published inissue 1…
Abstract Several dioctahedral clay minerals are related through reaction series. These series can be produced hydro-thermally from beidellite gel and montmorillonite by making simple changes in interlayer and solution chemistry. The series are: gel-K-beidellite-random illite/smectite-K-rectorite-illite K-montmorilloni…
Abstract Gelation and melting of aqueous gelatin were investigated by differential scanning calorimetry. This phenomenon can be analyzed as a conventional crystallization process assuming predetermined primary nucleation and unidirectional growth. The results were interpreted in terms of the fringed micelle model. Cal…
Abstract Samples of low‐density polyethylene (LDPE), high‐density polyethylene (HDPE), and tetratetracontane ( n ‐C 44 H 90 ) free from additives were heated in air at temperatures between 120 and 180°C. As a comparison, “as received” HDPE containing unspecified additives has also been included. The structural changes…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe octahedral hexasilver molecule. Seven crystal structures of variously vacuum-dehydrated fully silver(1+)-exchanged zeolite AYang Kim and Karl SeffCite this: J. Am. Chem. Soc. 1978, 100, 22, 6989–6997Publication Date (Print):October 1, 1978Publication History Published on…
The structure of an iron porphyrin with dichlorocarbene as ligand has now been estabished by X-ray analysis. The complex (1) accordingly contains a planar Fe(TPP)skeleton with H2O and CCl2 as axial ligands. The structural unit (2) is almost linear.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolyoxoanion supported organometallics: synthesis and characterization of .alpha.[(.eta.5-C5H5)Ti(PW11O39)]4-R. K. C. Ho and W. G. KlempererCite this: J. Am. Chem. Soc. 1978, 100, 21, 6772–6774Publication Date (Print):October 1, 1978Publication History Published online1 May…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLow-temperature solution preparation of Group 4B, 5B and 6B transition-metal dichalcogenidesRussell R. Chianelli and Martin B. DinesCite this: Inorg. Chem. 1978, 17, 10, 2758–2762Publication Date (Print):October 1, 1978Publication History Published online1 May 2002Published…
The influence of Ar on the recrystallization of implanted amorphous silicon layers has been studied. Investigation of the growth kinetics at temperatures up to 575 °C showed that epitaxial regrowth of silicon is halted if the Ar concentration at the amorphous–single-crystal interface reaches about 1.5×1020 cm−3. Furth…
The electrical properties of thin sandwich cells (M/Pc/Au) have been studied in a quantitative fashion. Here, M is either aluminum or indium (150–400 Å thick), and Pc represents metalfree phthalocyanine (H2Pc) or its zinc complex (ZnPc). The phthalocyanines were ∼3000 Å thick. These devices were assembled by depositio…