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71.
72.
K. C. Nicolaou Phil S. Baran Rolf Jautelat Yun He Kin Chiu Fong Ha‐Soon Choi Won Hyung Yoon Yong‐Li Zhong 《Angewandte Chemie (International ed. in English)》1999,38(4):549-552
A seven‐step cascade reaction —in which selective mesylation, epoxide formation, epoxide lysis, cyclization, reiterative oxidation, and nitrogen–oxygen exchange occur sequentially—facilitates the construction of the maleic anhydride moiety of CP molecules 1 and 2 (>93% yield per step). Unstable intermediates of this reaction sequence were detected, providing evidence for the proposed mechanism and resulting in the discovery of a new chemical entity. 相似文献
73.
Zhixun Ma Kin Man Yu Wladek Walukiewicz Peter Y. Yu Samuel S. Mao 《Applied Physics A: Materials Science & Processing》2009,96(2):379-384
We have deposited CdTe films by laser-assisted epitaxy approach and investigated the influence of substrate and film thickness
on the film properties. Grown on Si(001), GaAs(001), and quartz substrates; the CdTe films exhibit preferential orientation
along the cubic CdTe(111) direction. When the films are thin (<500 nm), a blueshift of the band gap and splitting of valence
bands were observed. These results are attributed to the existence of residual strains induced by mismatch of the film lattice
constant with that of the substrate, and by their difference in thermal expansion coefficients. The bulk band-gap energy of
1.5 eV was achieved on the surface of thick CdTe films grown on Si(001) substrate, indicating that strain was almost completely
relaxed in this case. Our results demonstrate that by a proper selection of substrate and film thickness it is possible to
grow film semiconductors with band gap approaching those of bulk crystals. 相似文献
74.
Biofuel cell controlled by enzyme logic network — Approaching physiologically regulated devices 总被引:1,自引:1,他引:0
Tsz Kin Tam Marcos Pita Maryna Ornatska Evgeny Katz 《Bioelectrochemistry (Amsterdam, Netherlands)》2009,76(1-2):4
A “smart” biofuel cell switchable ON and OFF upon application of several chemical signals processed by an enzyme logic network was designed. The biocomputing system performing logic operations on the input signals was composed of four enzymes: alcohol dehydrogenase (ADH), amyloglucosidase (AGS), invertase (INV) and glucose dehydrogenase (GDH). These enzymes were activated by different combinations of chemical input signals: NADH, acetaldehyde, maltose and sucrose. The sequence of biochemical reactions catalyzed by the enzymes models a logic network composed of concatenated AND/OR gates. Upon application of specific “successful” patterns of the chemical input signals, the cascade of biochemical reactions resulted in the formation of gluconic acid, thus producing acidic pH in the solution. This resulted in the activation of a pH-sensitive redox-polymer-modified cathode in the biofuel cell, thus, switching ON the entire cell and dramatically increasing its power output. Application of another chemical signal (urea in the presence of urease) resulted in the return to the initial neutral pH value, when the O2-reducing cathode and the entire cell are in the mute state. The reversible activation–inactivation of the biofuel cell was controlled by the enzymatic reactions logically processing a number of chemical input signals applied in different combinations. The studied biofuel cell exemplifies a new kind of bioelectronic device where the bioelectronic function is controlled by a biocomputing system. Such devices will provide a new dimension in bioelectronics and biocomputing benefiting from the integration of both concepts. 相似文献
75.
This paper is concerned with the existence of an optimal control problem for a quasi-linear elliptic obstacle variational inequality in which the obstacle is taken as the control. Firstly, we get some existence results under the assumption of the leading operator of the variational inequality with a monotone type mapping in Section 2. In Section 3, as an application, without the assumption of the monotone type mapping for the leading operator of the variational inequality, we prove that the leading operator of the variational inequality is a monotone type mapping. Existence of the optimal obstacle is proved. The method used here is different from [Y.Y. Zhou, X.Q. Yang, K.L. Teo, The existence results for optimal control problems governed by a variational inequality, J. Math. Anal. Appl. 321 (2006) 595-608]. 相似文献
76.
Stoponium, a bound state of the top squark and its antiparticle in a supersymmetric model, may be found in the ongoing Higgs searches at the LHC. Its WW and ZZ detection ratios relative to the standard model Higgs boson can be more than unity from the WW* threshold to the two Higgs threshold. The γγ channel is equally promising. Some regions of the stoponium mass below 150 GeV are already being probed by the ATLAS and CMS experiments. 相似文献
77.
The a-SiNx:H with a large bandgap of 3.8 eV was utilized to decorate ZnO nanowires. The UV emission from the a-SiNx:H-decorated ZnO nanowires are greatly enhanced compared with the undecorated ZnO nanowire. The deep-level defect emission has been completely suppressed even though the sample was annealed at temperatures up to 400 °C. The incorporation of H and N is suggested to passivate the defect states at the nanowire surface and thus result in the flat-band effect near ZnO surface as well as reduction of the nonradiative recombination probability. 相似文献
78.
We verify the feasibility of the proposed theoretical strategy for designing the broadband near-zero permittivity (ENZ) metamaterial at optical frequency range with numerical simulations. In addition, the designed broadband ENZ stack is used as meta-atoms to build functional nanophotonic devices with extraordinary properties, including an ultranarrow electromagnetic energy tunneling channel and an ENZ concave focusing lens. 相似文献
79.
Chung KH So CM Wong SM Luk CH Zhou Z Lau CP Kwong FY 《Chemical communications (Cambridge, England)》2012,48(14):1967-1969
A new class of easily accessible hemilabile benzimidazolyl phosphine ligands has been developed. The ligand skeleton is prepared from commercially available and inexpensive o-phenylenediamine and 2-bromobenzoic acid. With catalyst loading down to 0.5 mol% palladium, excellent catalytic activity towards the Suzuki-Miyaura coupling of aryl mesylates is still observed. This represents the lowest catalyst loading achieved so far for this reaction in general. X-Ray crystallography shows that new ligand L2 is coordinated with Pd in a κ(2)-P,N fashion. 相似文献
80.
The purpose of this paper is to present an iterative scheme for finding a common element of the set of solutions to the variational inclusion problem with multivalued maximal monotone mapping and inverse-strongly monotone mappings and the set of fixed points of nonexpansive mappings in Hilbert space.Under suitable conditions, some strong convergence theorems for approximating this common elements are proved. The results presented in the paper not only improve and extend the main results in Korpelevich(Ekonomika i Matematicheskie Metody,1976,12(4):747-756),but also extend and replenish the corresponding results obtained by Iiduka and Takahashi(Nonlinear Anal TMA,2005,61(3):341-350),Takahashi and Toyoda(J Optim Theory Appl,2003, 118(2):417-428),Nadezhkina and Takahashi(J Optim Theory Appl,2006,128(1):191- 201),and Zeng and Yao(Taiwanese Journal of Mathematics,2006,10(5):1293-1303). 相似文献