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31.
Min Jiang Katsunari Oikawa Tamio Ikeshoji 《Metallurgical and Materials Transactions A》2005,36(9):2307-2314
With a potential-energy function of Co described by the embedded-atom method (EAM), molecular-dynamics (MD) simulations were
performed for a series of initial fcc configurations with different types of dislocations or preset hcp embryos. The gliding
process of a Shockley dislocation on a closepacked plane has been observed, which starts from the origin of the dislocation
and proceeds at a high speed of 280 m/s toward a certain direction. An atom which has been swept by the dislocation line was
detected to contribute a displacement close to the Burgers vector of a Shockley dislocation. It is in this way that a new
stacking sequence is produced and an hcp lamella grows in the fcc structure. A similar gliding process has been observed in
the case where an intrinsic stacking fault is preexisting in the fcc structure. The transformation is, again, toward forming
a local hcp region. These results prove that a special dislocation in the fcc structure can act as an embryo of the hcp, as
described in many dislocation mechanisms of the martensitic transformation. The fcc → hcp phase-tranformation process of Co
has been further reproduced by a simulation initiated from an fcc/hcp two-phase configuration. It yields a single hcp crystal
as the final transformed product. 相似文献
32.
33.
The freezing point depression, ΔT, of swollen DCP-, TT- and sulphur-cured natural rubber in benzene was observed. The dependence of the parameter, aH, introduced by Kuhn, was not affected by the type of structure of crosslink sites. It was found from the comparison of the experimental results and scaling law that aH can reflect not only the difference in three-dimensional structure of network between a degraded and an undegraded rubber vulcanizates but also the difference in degraded network structures between rubber samples with various conditions of degradation. 相似文献
34.
Kokubun Y. Suzuki S. Fuse T. Uehara H. Iga K. Oikawa M. Misawa S. 《Electronics letters》1983,19(24):1009-1010
A novel mode scrambler for multimode optical waveguides is proposed to stabilise branching characteristics against the mode excitation conditio. A 2 × 2 optical star coupler is fabricated using this mode scrambler, and a stable branching ratio is realised with an excess insertion loss of 2.7 dB. 相似文献
35.
A theoretical study has been carried out in order to explain the sensitivities of electron beam and X-ray resists. A preliminary investigation reveals that the behavior of these resists, on irradiation by high energy radiation, may be considered to be the electronically-excited species in the polymer. To elucidate the chemical reactions in the excited states the adiabatic potential curves are calculated by the INDO/S procedure, which considers all the valence electrons and all the singly excited electronic configurations. Polyethylene and polyisobutylene were chosen as representative of crosslinkable and degradable polymers, respectively, since there is a parallelism between the beam sensitivity of resists and the effects of high energy radiation on polymers. Polyisobutylene has many antibonding curves favorable for the main chain scission in the excited states and polyethylene does not except for one improbable state. It was concluded that degradability is explainable by the ease of bond fission in the excited states; the crosslinkability is considered to be nondegradable property. 相似文献
36.
K Ajiki Y Murakawa T Yamashita N Oikawa K Sezaki Y Kotsuka A Furuse M Omata 《Canadian Metallurgical Quarterly》1996,29(2):155-160
In twenty eight patients with iron deficiency the efficacy of iron-acetil-transferrin treatment (2-3 mg/kg/die) has been evaluated from the changes of the following variables: RBC and reticulocyte count, Hb concentration, MCV, MCH, serum ferritin, serum iron, TIBC, and ZnPP. These variables were assessed before and after three months of treatment in all patients, and after three months from the end of the treatment in thirteen patients. At the end of the treatment there was a significant increase of RBC count, Hb concentration, MCV, MCH, serum ferritin, serum iron, and TIBC, a significant decrease of ZnPP, while reticulocyte count remained essentially unchanged. After three months from the end of the treatment only serum ferritin and ZnPP underwent an additional significant increase and decrease, respectively. In twenty-six patients serum ferritin values returned to normal. The changes of RBC and reticulocyte count, Hb concentration, MCV, serum iron, and TIBC were larger the lower the initial values, suggesting that the efficacy of the treatment is greater the more serious the iron deficiency. 相似文献
37.
Summary Schiffs bases of polyallylamine were synthesized by the reaction with four aldehydes. Salicylaldehyde (S)- and 2-pyridinecarboxaldehyde (P)-Schiff's base could be used as reverse osmosis membranes when crosslinked with divinyl sulfone, diacetyl or ethylene glycol diglycidyl ether. S-base membrane had a high mechanical strength but poor water permeability (K1), while P-base membrane showed a high rejection, particularly against CoCl2, and a high K1 because of chlate formation, but poor strength. The membranes of P-base and a hybrid PS-base exhibited a possibility of separating alkali metal salts and transition metal salts from each other. 相似文献
38.
The freezing-point depression, ΔT, of swollen dicumene peroxide cured natural rubber in benzene has been measured. The parameter aH, introduced by Kuhn, which varies inversely as ΔT, should be regarded as an indication of the depression. The anomalous depression is considered to occur due to a non-frozen benzene area formed on the surrounding network chains. From comparison of the scaling law and the experimental results, it was clear that aH can reflect not only the quantity corresponding to network chain density determined by conventional methods but also the difference in three-dimensional network structure between degraded and undegraded rubber vulcanizates. 相似文献
39.
The copolymer prepared from 4-vinylpyridine and methyl vinyl ketone could form a dense and tough membrane which is stronger than cellulose acetate when crosslinked with malonyl dihydrazide (MD) or 2-phenyl-4,6-dihydrazino-s-triazine (PDT), showing a fair performance in reverse osmosis for NaCl and CoCl2 feed. The relationship between the content of MD or PDT and the membrane performance was investigated. An increase in MD or PDT led to an increase in membrane thickness and water content as well as the performance. A maximum rejection was obtained at ca. 30 mol % MD and ca. 13 mol % PDT based on MVK, and a maximum membrane strength at 20–30 mol % crosslinking agent. A membrane of a lower NaCl rejection tended to be permselective due to the complexation of the CoCl2 with membrane. About 1:1 copolymer gave membranes of a higher rejection, which may be related to monomer arrangement in the copolymer chain. There methods for the flux improvement were presented and discussed: preparation of a copolymer blend membrane containing a hydrophilic monomer, crosslinking quaternization of membranes with diiodobutane, and oximation of the membrane material in order to introduce hydrophilic groups. 相似文献
40.