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81.
In-Suk Wee 《Probability Theory and Related Fields》1990,85(4):469-488
Summary Let {X
t
} be a 1 process with stationary independent increments and its Lévy measurev be given byv{yy>x}=x
–L
1
(x), v{yy<–x}=x
–L
2
(x) whereL
1,L
2 are slowly varying at 0 and and 0<1. We construct two types of a nondecreasing functionh(t) depending on 0<<1 or =1 such that lim inf
a.s. ast 0 andt for some positive finite constantC.This research is partialy supported by a grant from Korea University 相似文献
82.
83.
Xie XN Chung HJ Xu H Xu X Sow CH Wee AT 《Journal of the American Chemical Society》2004,126(24):7665-7675
We report, for the first time, the native oxide decomposition/etching and direct local oxide growth on 6H-SiC (0001) surface induced by atomic force microscopy (AFM). Surface native oxide was decomposed and assembled into protruded lines when the negatively biased AFM tip was scanned over surface areas. The mechanism of decomposition was found to be governed by the Fowler-Nordheim emission current enhanced by the negatively biased AFM tip. Direct oxide growth on the SiC surface was achieved when the AFM tip was immobilized and longer bias duration applied. In particular, the aspect ratio of oxide grown on SiC was found to be several times higher than that on the Si surface. The improved aspect ratio on SiC was attributed to the anisotropic OH(-) diffusion involved in vertical and lateral oxidation along the polar and nonpolar directions such as [0001] and [110] axis in SiC crystal. The electron transport in the above AFM grown oxide on SiC was further investigated by I-V characteristics. The dielectrical strength of AFM oxide against degradation and breakdown under electrical stressing was evaluated. 相似文献
84.
Sequencing of peptides via low-energy collision-induced dissociation of protonated peptides typically yields b(n) and y(n) sequence ions. The isomeric residues leucine and isoleucine rarely can be distinguished in these experiments since they give b(n) and y(n) sequence ions of the same m/z. Siu's pioneering work on electrospray ionization of copper complexes of peptides (Chu IK, Rodriquez CF, Lau TC, Hopkinson AC, Siu KWM. J. Phys. Chem. B 2000; 104: 3393) provides a way of forming radical cations of peptides in the gas phase. This method was used to generate M(+ small middle dot) ions of the two isomeric peptides Gly-Leu-Arg and Gly-Ile-Arg in order to compare their fragmentation reactions. Both radical cations fragment to give even electron y(2) and y(1) sequence ions as well as side-chain radical losses of CH(3) and CH(3)CH(2) for isoleucine and (CH(3))(2)CH for leucine. In contrast the [M + H](+) and [M + 2H](2+) ions do not allow distinction between the isomeric leucine and isoleucine peptides. 相似文献
85.
Mieock Kim Moon Young Jin Chul Wee Lee Chong Shik Chin 《Journal of organometallic chemistry》2004,689(22):3535-3540
The second generation of Grubbs type catalyst, (PCy3)(H2IMes)Cl2RuCHPh (1) undergoes the Cl replacement with CH3CN to give cationic ruthenium carbene complexes, [(RCN)3(H2IMes)RuCHPh](OTf)2 (2, R = CH3 (a), Ph (b)) in the presence of AgOTf. The reaction of 2a with H2O in the presence of CH3CN gives (aqua)ruthenium complex, [Ru(H2IMes)(NCCH3) 4(H2O)](OTf)2 (3) and benzaldehyde. Benzaldehyde is also observed in the reaction of 1 with H2O. Plausible reaction pathways are suggested for the degradation of ruthenium benzylidenes to give benzaldehyde on the basis of the isotope labeling experiments. 相似文献
86.
87.
J. H. Moon M. Ebihara B. F. Ni B. Arporn P. Setyo R. M. Theresia B. S. Wee N. A. Abd. Salim P. C. B. Pabroa 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(1):217-221
Since 2000, collaborative studies for applying NAA have been performed through the Forum for Nuclear Cooperation in Asia (FNCA)
sponsored by the Japanese Government. White rice is a main food for Asians and thus was selected as a common target sample
for a collaborative study in 2008. Seven Asian countries including China, Indonesia, Japan, Korea, Malaysia, Philippines and
Thailand, are greatly concerned about the composition of arsenic, heavy metals, and essential trace elements and took part
in this study. Rice samples were purchased and prepared by following a protocol that had been proposed for this study. Samples
were analyzed by their own NAA systems. In each country, more than 10 elements were examined and the results were compared.
These data will be very useful in the monitoring of the levels of food contamination and to evaluate the nutritional status
for people living in Asia. 相似文献
88.
Zhaofu Fei Dr. Dun‐Ru Zhu Prof. Xue Yang Dr. Lingjie Meng Dr. Qinghua Lu Prof. Wee Han Ang Dr. Rosario Scopelliti Dr. Christian G. Hartinger Dr. Paul J. Dyson Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(22):6473-6481
A series of fluorescent imidazolium‐based salts containing the cation [AnCH2MeIm]+ (in which An=anthracene and Im=the imidazolium cation) with Cl?, BF4?, PF6?, SO3CF3?, [N(CN)2]?, [N(SO2CF3)2]?, or PhBF3? anions have been prepared and characterized. X‐ray diffraction analysis of four of the salts reveals a number of C? H???X‐type (X=O, N, F) hydrogen bonds between the hydrogen atoms from the imidazolium ring and in some cases from the anthracene ring with the electronegative atoms of the anions. Additionally, C? H???π interactions can be found in all the salts analyzed by X‐ray diffraction, whereas π–π stacking is observed only in the salt containing the phenyltrifluoroborate anion. Fluorescence emission analysis in acetonitrile shows that the fluorescence of these salts varies significantly according to the nature of the anion, and correlates to the extent of ion pairing present in solution. Photodimerization of these salts was observed, and in one case a dimer has been isolated and characterized by X‐ray crystallography. 相似文献
89.
The fermentative production of lactic acid from cheese whey and corn steep liquor (CSL) as cheap raw materials was investigated by using Lactobacillus sp. RKY2 in order to develop a cost-effective fermentation medium. Lactic acid yields based on consumed lactose were obtained at more than 0.98 g/g from the medium containing whey lactose. Lactic acid productivities and yields obtained from whey lactose medium were slightly higher than those obtained from pure lactose medium. The lactic acid productivity gradually decreased with increase in substrate concentration owing to substrate and product inhibitions. The fermentation efficiencies were improved by the addition of more CSL to the medium. Moreover, through the cell-recycle repeated batch fermentation, lactic acid productivity was maximized to 6.34 g/L/h, which was 6.2 times higher than that of the batch fermentation. 相似文献
90.
Unprecedented Acid‐Promoted Polymerization and Gelation of Acrylamide: A Serendipitous Discovery 下载免费PDF全文
Siew Yin Chan Dr. Shermin S. Goh Dr. Qingqing Dou Benjamin Qi Yu Chan Dr. Wee Sim Choo Prof. David James Young Prof. Xian Jun Loh 《化学:亚洲杂志》2018,13(14):1797-1804
Dilute acid polymerizes degassed, aqueous acrylamide with concomitant gelation, without the need for added free radical initiator or cross‐linking agent. This reaction is accelerated by sonication or UV irradiation, but inhibited by adventitious oxygen or the addition of a free radical inhibitor, suggesting an acid‐accelerated free radical process. The resulting hydrogels are thixotropic in nature and partially disrupted by the addition of chaotropic agents, indicating the importance of hydrogen bonding to the 3D network. This discovery was made while trying to prepare pectin‐polyacrylamide hydrogels. We observed that pectin initiated the gelation of acrylamide, but only if the aqueous pectin samples had a pH lower than ca. 5. 相似文献