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Damage produced in p-type silicon by neutron irradiation at room temperature was studied by deep-level transient spectroscopy (DLTS). The production of three defects (Ev + 0.15, Ev + 0.34 and Ev + 0.45 eV) by neutron irradiation and the formation of two defects (Ev + 0.25 and Ev + 0.21 eV) during annealing were reported. It was found that many properties of the neutron damage were similar to those of the electron damage obtained by other works as far as the DLTS measurements are concerned. The DLTS measuements indicated no evidence for the production of defect clusters in the neutron damage. By comparing with the results previously obtained by the Hall effect measurements, it was found that the DLTS measurements mainly evaluated the properties of the point defects outside the clusters. The fact that the DLTS measurements did nto reflect the properties fo the defect clusters was ascribed to the reduction of majority carrier capture by defects inside the clusters due to the potential barrier formed by the cluster-space-charge regions.  相似文献   
136.
Interaction of tocored with unsaturated fatty esters   总被引:1,自引:0,他引:1  
Tocored, an oxidation product of tocopherol and its model, 2,2,7,8-tetramethyl-5,6-chromanquinone reacted with methyl linoleate at an elevated temperature to form an adduct with isomerized linoleate. Oxidation of tocored in fatty esters produced a variety of products, depending on the degree of unsaturation of the esters. With methyl palmitate no addition product was detected but tocopurple and tocoreddimer were identified as minor products irrespective of the degree of saturation. A mechanism involving the interaction of tocored with lipid radicals to yield an adduct as the consequence of antioxidative action of tocored is postulated.  相似文献   
137.
One difficulty in analyzing the state of filament in the dry spinning process is that in the boundary conditions required to solve the equations of mass, momentum and energy which are derived on the consideration of balance with respect to infinitesimally small element are not given a priori. The equations which include these boundary conditions in themselves are derived by considering mass, momentum, and energy balances with respect to the entire cross section of filament. These additional macroscopic equations are simplified to a great extent by assuming the flat velocity profile through the cross section of filament. Besides, in the steady state, these macroscopic equations are modified to give the equations of average solvent content, spinning tension, cross-sectional area, and average temperature. When the spinning conditions are given and the physical constants are measured for a given polymer and solvent system, it becomes possible to calculate the state of filament by solving these microscopic and macroscopic equations simultaneously without resorting to actual spinning.  相似文献   
138.
The study of the cation site preferences related to Rh3+ or Sn4+ ions in the spinel lattice leads to a series of new spinels. Various sulfo-spinels containing some of the transition elements such as Mn, Fe, Co and Ni, have been synthesized and the cation distributions and u-parameters were determined. Some magnetic and electrical properties were measured for Fe2RhS4 and Cd1?xFe1+xSnS4 (0 ≤ x ≤ 0.9).  相似文献   
139.
The behavior of polycations as flocculants for kaolinite was examined by means of turbidity measurement, with the use of the following four kinds of cationic polysulfones, with molecular weights ranging from 14,000 to 330,000; diallyldimethylammonium chloride SO2 copolymer [P(DADMAmCl? SO2)], diallyldiethylammonium chloride–SO2 copolymer [P(DADEAmCl? SO2)], diallylmethylamine hydrochloride–SO2 copolymer [P(DAMA? HCl? SO2)], diallylamine hydrochloride–SO2 copolymer [P(DAAHCl? SO2)]. The effect of the degree of polymerization on the flocculation was remarkable at low molecular weight range. The flocculation value, which is defined as the quantity of the polycation required to obtain 50% transparency at 660 mμ of the supernatant fluid of 2% kaolinite suspension, was inversely proportional to the degree of polymerization to the 0.734 power in the case of P(DADMAmCl? SO2). This can be understood as the extension of Schulze-Hardy's law. The four different kinds of polysulfones having a similar molecular weight show almost the same capacity for flocculation in acidic or neutral solution. In alkaline solution, however, P(DAMAHCl? SO2) and P(DAA? HCl? SO2) are less effective and have higher flocculation values than P(DADMAmCl? SO2) and P(DADEAmCl? SO2), which are classified as polyquaternary ammonium chlorides. Moreover the difference increases with increasing pH. This may be attributable to the difference of the dissociability of the polycation. The degree of dissociation of P(DAMA? HCl? SO2) or P(DAA? HCl? SO2) decreases with increasing pH and more additive is required to neutralize negative charges on kaolinite. On the other hand, P(DADMAmCl? SO2) and P(DADEAmCl? SO2) are almost completely dissociated and are good flocculants over a wide range of pH.  相似文献   
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