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905.
K.Y. Lim Y.S. Lee Y.D. Chung I.W. Lyo C.N. Whang J.Y. Won H.J. Kang 《Applied Physics A: Materials Science & Processing》2000,70(4):431-434
In this study, the grain boundary diffusion of Cu through a TiN layer with columnar structure was investigated by X-ray photoelectron
spectroscopy (XPS). It was observed that Cu atoms diffuse from the Cu layer to the surface along the grain boundaries in the
TiN layer at elevated temperature. In order to estimate the grain boundary diffusion constants, we used the surface accumulation
method. The diffusivity of Cu through TiN layer with columnar structure from 400 °C to 650 °C is Db≈6×10−11exp(−0.29/(kBT )) cm2/s.
Received: 18 May 1999 / Accepted: 8 September 1999 / Published online: 23 February 2000 相似文献
906.
Mei-Yeut Lim Tse-Chuan Chou Xi-Zhang Lin Chiung-Yu Chen Tzong-Rong Ling Shu-Chu Shiesh 《Colloids and surfaces. B, Biointerfaces》2000,17(4):265-274
Application of nonionic surfactants in chemolitholysis was developed to combine two immiscible cholelitholytic solvents, MTBE and EDTA, into a homogeneous solution to increase the efficiency of gallstone dissolution. Eight kinds of Sinopol were employed to investigate and prepare the homogeneous solution, which included MTBE, EDTA (2wt.%) aqueous solution and the Sinopol, thereby, an in vitro study of chemolitholysis was carried out. Three kinds of gallstones were characterized by FTIR and SEM. The dissolution percentage of three kinds of gallstones in the homogeneous (Sinopol mixed) solution was evaluated and a comparison of the average dissolution percentage between these Sinopol mixed solutions and traditional cholelitholytic solvents was made. The composition of gallstones was classified into oil-soluble and water-soluble groups. Furthermore, the hydrophobic and hydrophilic properties of solvents corresponding to oil-soluble and water-soluble gallstone components were analysed and discussed with a phase diagram. 相似文献
907.
Hyoung Lim Koh Sang Ho Lee Kyung Lim Kim 《Reaction Kinetics and Catalysis Letters》2000,71(2):239-244
The effect of MoO3 addition to alumina supported vanadia catalysts on the catalytic activity for the selective catlaytic reduction of NO is investigated. Upon the addition of MoO3, catalytic activity is enhanced and the particle size of V2O5 which is shown by the results of XRD and Raman spectroscopy is decreased. The MoO3-V2O5/Al2O3 catalyst also exhibits more resistance to SO2 deactivation than V2O5/Al2O3 does. 相似文献
908.
We demonstrate that all the known single- and double-logarithm summations for a parton distribution function can be unified
in the Collins–Soper resummation technique by applying soft approximations appropriate in different kinematic regions to real
gluon emissions. Neglecting the gluon longitudinal momentum, we obtain the (double-logarithm) resummation for two-scale QCD processes, and the Balitsky–Fadin–Kuraev–Lipatov (single-logarithm) equation
for one-scale processes. Neglecting the transverse momentum, we obtain the threshold (double-logarithm) resummation for two-scale
processes, and the Dokshitzer–Gribov–Lipatov–Altarelli–Parisi (single-logarithm) equation for one-scale processes. If we keep
the longitudinal and transverse momenta simultaneously, we derive a unified resummation for a large Bjorken variable x, and a unified evolution equation appropriate for both intermediate and small x.
Received: 9 March 1999 / Revised version: 12 April 1999 / Published online: 3 August 1999 相似文献
909.
A series of miniemulsion systems based on styrene/azobisisobutyronitrile in the presence of poly(methyl methacrylate‐b‐2‐(dimethylamino)ethyl methacrylate) as a surfactant and hexadecane (HD) as a cosurfactant were developed. For comparison, a series of pseudoconventional emulsions also were carried out with the same procedure used for the aforementioned series but without the cosurfactant (HD). Both the droplet size and shelf life were also measured. Experimental results indicate that it is possible to slow the effect of Ostwald ripening and thereby produce a stable miniemulsion with the block copolymer as the surfactant and HD as the cosurfactant. In addition, the extent to which varying the surfactant concentration and copolymer composition could affect both the polymer particle size during the polymerization and the polymerization rate was examined. Variation in the polymer particle sizes during polymerization indicates that droplet and aqueous (micellar or both homogeneous) nucleation occurs in the miniemulsion polymerization. With the same concentration of the surfactant used in the miniemulsion polymerization, the polymerization rates of systems with M12B36 are faster than those of systems with M12B12. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1818–1827, 2000 相似文献
910.
Soon Young Cha Jong Keun Lee Bum Soon Lim Taek Seung Lee Won Ho Park 《Journal of polymer science. Part A, Polymer chemistry》2001,39(6):880-887
The introduction of a conjugated vinyl group to chitooligosaccharide (COS) has been easily accomplished by the coupling of glycidyl methacrylate (GMA) to COS in aqueous solution without an additional catalyst. Depolymerization of chitosan was carried out by deaminative cleavage using sodium nitrite. The average degree of polymerization of COS could be controlled by varying the molar ratio of sodium nitrite and the amino group of chitosan. The degree of substitution (percentage), as determined by 1H NMR, of GMA to COS increased up to 60% at a reaction time of 48 h. The structure of products (COS‐GMAs) were identified by Fourier transform infrared spectroscopy, 1H NMR, and 13C NMR. The resulting COS‐GMAs were readily soluble in neutral water, like the original COS, and exhibited an excellent antimicrobial activity. The reactivity of COS‐GMA was investigated by the reaction with poly(vinyl alcohol) (PVA). The reaction products were found to have a lower crystallinity than PVA because of the introduction of the COS‐GMA units. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 880–887, 2001 相似文献