摘要:

AbstractPolymer processing consists of basically three functional steps: plasticization of a solid polymer, forming of the plasticized polymer into a desired shape, and solidification of the formed polymer. Polymer processing requires a good knowledge in the melt rheology, morphology, mechanochemistry, melting and crystallization behavior of the polymer as well as engineering knowledge in heating, cooling and deformation processes. Thus, it presents an unusual challenge to polymer engineers and scientists. The gap between theory and practice is extremely large in polymer processing. In spite of extensive fundamental knowledge, many problems in the procedure still remains “practically” unsolved. In this paper, three important examples of the unsolved problems in polymer processing—namely, screw extrusion process, weld‐line (self‐diffusion) behavior of polymer melt, and temperature build‐up in capillary flow—are discus

ISSN:0028-7113    

DOI:10.1111/j.2164-0947.1974.tb01582.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractIncreasing emphasis is being placed upon the role of the M.D. as the leader of a team of health professionals to whom he delegates many hitherto jealously guarded responsibilities. But most M.D.s are ill‐prepared for their new role. One effective way of training for this “new look” in M.D.s is through an integrated Health Sciences approach with student doctors, nurses, pharmacists, and dentists involved in closely integrated training programs. One ongoing program is disc

ISSN:0028-7113    

DOI:10.1111/j.2164-0947.1974.tb01583.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThe effect of protein intake (47, 95, and 142 g) on calcium retention, calcium absorption, and urinary calcium of 33 young adult males was determined at calcium intakes of 500, 800, and 1400 mg daily. Magnesium intake was 400 (27 subjects) or 490 mg (six subjects). The calcium‐to‐phosphorus ratio was 1.0 (1400 mg calcium intake), 0.8 (800 mg calcium intake), and 0.6 (500 mg calcium intake).When consuming the 47‐g protein intake, the subjects were consistently in calcium balance and the amount of calcium retained was unaffected by the calcium intake. At the 95‐g protein intake, none of the subjects were in calcium balance when 500 mg calcium was given, but they did achieve balance when 800 mg was given. When 142‐g protein was ingested, no subject was in balance at either the 500‐ or 800‐mg calcium intake and only three of 15 subjects were in balance at the 1400‐mg intake. Calcium absorption was not affected by dietary protein at an intake of 500 mg calcium, but significantly more calcium was absorbed at medium or high protein intakes than at low when 800 or 1400 mg calcium was given, the maximal protein effect having been reached at the 95‐g protein level. Urinary calcium was significantly affected by protein intake. All subjects, regardless of level of calcium intake, excreted less calcium when given the low protein diet than when given the medium, and all except two subjects excreted less when given the medium than when given the

ISSN:0028-7113    

DOI:10.1111/j.2164-0947.1974.tb01584.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractIndustrial populations provide unique opportunities for epidemiologic research to study risk factors in chronic disease and identify health hazards in the work environment. In such populations, demographic, morbidity, and mortality data are readily accessible and generally reliable. Moreover, industrial populations are usually stable enough to permit long‐term follow‐up for prospective studies. In this paper, the major findings of several epidemiological studies done in a large corporation are revie

ISSN:0028-7113    

DOI:10.1111/j.2164-0947.1974.tb01585.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThe nonthermal structural rearrangements of cyclooctatetraene to semibullvalene and 2,3‐dihydrotriquinacen‐2‐one are described. The first pathway, which is entirely general in its scope, entails as its key step the Ag(I)‐catalyzed 1,8‐bishomocubane → snoutane isomerization reaction. Subsequent hydrolysis‐oxidation provides 9,10‐diazasnoutenes, which cannot be isolated but lose nitrogen rapidly with generation of the semibullvalenes. The equilibrium imbalances that arise upon monosubstitution and 2,8‐annulation of this divinylcyclopropane system are also outlined. Cycloaddition of TCNE to cyclooctatetraeneiron tricarbonyl affords an unusual α,π‐Fe(CO)3complex, oxidative decomposition of which gives 2,2,3,3‐tetracyanodihydrotriquinacene. A four‐step conversion of the latter to triquinacene‐2‐carboxylic acid is outlined. Resolution of the acid and conversion of the chiral material to (+)‐2,3‐dihydrotriquinacen‐2‐one serves as a prelude to dimerization of these “halves” to potential dodecahedrane precursors. The thermally promoted degenerate isomerization and rearrangement reactions of a variety of cyclooctatetraenes are next presented. Lastly, the latent potential of the [8]annulene ring system to function as a neighboring grou

ISSN:0028-7113    

DOI:10.1111/j.2164-0947.1974.tb01586.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

ISSN:0028-7113    

DOI:10.1111/j.2164-0947.1974.tb01587.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

ISSN:0028-7113    

DOI:10.1111/j.2164-0947.1974.tb01588.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

ISSN:0028-7113    

DOI:10.1111/j.2164-0947.1974.tb01589.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY