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71.
Wang Y Zang K Chua S Sander MS Tripathy S Fonstad CG 《The journal of physical chemistry. B》2006,110(23):11081-11087
Dense, crystalline arrays of InGaN nanorings, nanodots, and nanoarrows have been fabricated on GaN substrates by template-assisted nano-area selective growth. To create the nanostructures, we have used nanoporous anodic alumina films as templates to pattern nanopores in an SiO2 transfer layer, and then used this patterned SiO2 layer as a template for nitride growth by metalorganic chemical vapor deposition. We have varied the diameter of the deposited nitride nanostructures from 35 to 250 nm by changing the initial anodic alumina template structure. In addition, by controlling the nitride growth time we have created various types of nanostructures, from nanorings to nanoarrows. This structural evolution begins with the nucleation and formation of a nanoring structure, followed by coalescence and growth to form faceted nanodots, and finally lateral overgrowth to form faceted nanoarrows. 相似文献
72.
A novel organocatalytic asymmetric tandem Michael-Henry reaction catalyzed by 9-amino-9-deoxyepiquinine (VI) has been developed. The reaction was efficiently catalyzed by catalyst VI to give highly functionalized cyclohexanes with four stereogenic carbons including two quaternary stereocenters in excellent enantioselectivities (97 to >99% ee) and high diastereoselectivities (93:7-99:1 dr). Thus, the first organocatalytic asymmetric Henry reaction of common ketones as acceptors is shown. 相似文献
73.
Identification of a serine protease inhibitor homologue in Bird's Nest by an integrated proteomics approach. 总被引:4,自引:0,他引:4
For centuries, the edible nests of Collocalia spp. ("Bird's Nests") have been used as a Chinese delicacy that had been claimed to be an effective health-giving tonic. However, clinical studies indicated that in Singapore, Bird's Nest is the most common cause of food-induced anaphylaxis in children, which could lead to potentially life-threatening allergenic reactions. The purpose of this study was to characterize the major allergens in Bird's Nest by using the combined technologies of two-dimensional gel electrophoresis (2-DE), immunochemistry, N-terminal protein sequencing, and mass spectrometry. Results from the immunostaining of the Western blots of the Bird's Nest 2-DE separated proteins with the sera from allergic patients indicated the presence of a major allergen of 66 kDa. Initial searches of the matrix assisted laser desorption/ionization--time of flight--mass spectrometry (MALDI-TOF-MS) tryptic peptide masses of the allergen in the SWISS-PROT and NCBI nonredundant databases revealed that this protein was novel. Based on the partial protein sequence information obtained from N-terminal microsequencing and nanoelectrospray-tandem MS, the 66 kDa immunoreactive allergen was found to be homologous to ovoinhibitor, a Kazal-type serine protease inhibitor, which is one of the dominant allergens found in chicken egg white. 相似文献
74.
75.
S.K.?Donthu D.Z.?ChiEmail author S.?Tripathy A.S.W.?Wong S.J.?Chua 《Applied Physics A: Materials Science & Processing》2004,79(3):637-642
The micro-Raman spectroscopic technique was used to investigate vibrational properties of NiSi thin films formed on three different (100)Si substrates: non-implanted, 20 keV BF2+-implanted, and 20 keV B+-implanted. Raman measurements were also performed on NiSi powder to identify various phonon modes associated with different selection rules of group theory. It was found that the Raman peaks for NiSi thin films formed on the BF2+-implanted substrate were broader and shifted to lower frequencies compared to those for films formed on the other substrates. The broadening of the Raman peaks for these films, which also exhibit much improved thermal stability, is attributed to the small grains that probably result from the segregation of fluorine to grain boundaries and interfaces. It is further proposed that grain boundary segregation influences the stress in the silicide film, resulting in shifts in phonon peak positions. PACS 78.30.Am; 74.25.Kc; 68.35.Dv; 68.55.Ln; 66.30.Jt 相似文献
76.
Kok Seng Chua 《Archiv der Mathematik》2003,81(1):11-21
Let p(n)
denote the number of unrestricted partitions of the positive integer
n, and let
m be a prime $\geq 13$. We prove, for
k = 1, explicit congruences of the form
where $r_{m,k}, \delta_{m,k}$ are integers depending on m and
k and $\phi_{m,k}(z)$ are explicitly computable level one
holomorphic modular forms of small weight. We also give theoretical and numerical support
that the congruences also hold for k > 1.
Our main idea is a level reduction result for the modular forms which originated
from Atkin-Lehner. From our result, we deduce periodicity properties for the
partition function with short periods which improve upon recent results
of K. Ono.
Received: 24 January 2002 相似文献
77.
78.
The fate of six different branched-chain fatty acids (BCFAs) in an anaerobic environment of a river sediment was studied in
vitro by culturing enrichment consortia. The anaerobic consortium of BCFA-degrading genus degraded BCFAs with tertiary carbons
through β-oxidation, followed by methanogenesis by methane-producing anaerobic bacteria. The consortium could not degrade
BCFAs with quaternary carbon. Degree of branching at the alpha or beta position along the carbon chain interfered with the
beta-oxidation mechanisms of the branched-chain fatty acid. 相似文献
79.
Difference between lattice constants of silicon (Si) and diamond is approximately 52%. Therefore Si1—xCx which has a lattice constant between two materials should be formed on Si substrate to be diamond nucleation sites and reduce the stress between the diamond film and Si substrate. Si wafers with carbonization and dc-biasing pretreatment were prepared in a microwave plasma chemical vapor deposition (CVD) system, then they were investigated by Raman spectroscopy, Photoluminescence (PL), chemical etching and scanning electron microscope (SEM) to study the pretreatment effect. This was achieved by studying a series of samples pretreated by carbonization and dc-biasing. 相似文献
80.
In this study, activated sludge bacteria from a conventional wastewater treatment process were induced to accumulate polyhydroxyalkanoates
(PHAs) under different carbon-nitrogen (C:N) ratios. As the C:N ratio increased from 20 to 140, specific polymer yield increased
to a maximum of 0.38 g of polymer/g of dry cell mass while specific growth yield decreased. The highest overall polymer production
yield of 0.11 g of polymer/g of carbonaceous substrate consumed was achieved using a C:N ratio of 100. Moreover, the composition
of polymer accumulated was dependent on the valeric acid content in the feed. Copolymer poly (3-hydroxybutyrate-co-3-hydroxyvalerate)
[P(3HB-co-3HV)] was produced in the presence of valeric acid. The 3-hydroxyvalerate (3HV) mole fraction in the copolymer was
linearly related tovaleric content in the feed, which reached a maximum of 54% when valeric acid was used as sole carbon source.
When the 3HV U in the polymer increased from 0–54 mol%, the melting temperature decreased from 178° to 99°C. Thus, the composition,
and hence the mechanical properties, of the copolymer produced from activated sludge can be controlled by adjusting the mole
fraction of valeric acid in the feed medium. 相似文献