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991.
Naoki Tanaka Yoshiaki Hamada Masamichi Tsuboi Shuji Saito Yasuki Endo Eizi Hirota 《Journal of Molecular Spectroscopy》1984,103(1):87-94
15NO2 (88 lines) in the ground state has been observed in the microwave spectral region up to 170 GHz. The least squares analysis gave the higher order distortion terms of rotational and spin-rotational Hamiltonian. 相似文献
992.
A variety of α-chloromethyl, α,α-dichloromethyl, and α,α,α-trichloromethyl ketones were synthesized from aldehyde utilizing cathodic reduction as key reactions. 相似文献
993.
994.
995.
A new refractometer has been developed based on changes in the effective refractive index (RI) of the highest-order TE (or TM) mode in a prism-coupled multimode planar waveguide induced by interaction between an evanescent field and a liquid sample. The waveguide was a 100-mu;m -thick quartz plate fixed on a poly(methyl methacrylate) support containing a flow cell. A pair of prism couplers contacted the quartz plate in the flow-cell region. Such an optical sensor can detect the RI of liquid in a wide range by monitoring the resonant angle of the highest-order mode that changes order number with changes in the sample's RI. When a highest-order mode corresponding to a given RI range is used as the sensor probe, a slight RI change in this range can be detected by measurement of the output light intensity. With this method the sensor was demonstrated to have a resolution of 3x10(-5) for the RI of an aqueous solution. Combining this result with theoretical calculation indicates that the sensor can detect a 0.5-nm-thick monolayer adsorbed from an aqueous solution. Therefore, the sensor is suitable for real-time detection of biomolecular interactions. 相似文献
996.
Optical characterization of photonic crystal delay lines based on one-dimensional coupled defects 总被引:5,自引:0,他引:5
We performed optical characterizations of optical delay lines based on photonic crystal waveguides. The delay lines were composed of cylindrical air holes in silicon-on-silicon-dioxide ridge waveguides, defects were periodically created by means of increasing the separation of two neighboring air holes, and the structure was designed to have flat-transmittance impurity band. We clearly observed an impurity band with a bandwidth of ~30 nm and a maximum transmittance of ~0.5 at an operating wavelength of ~1.55 microm . A 600-fs delay was confirmed with a 20-microm -long delay line. A good agreement was confirmed between the experimental results and the calculations. 相似文献
997.
beta-Methoxytyrosine (beta-OMeTyr) is a stereoundefined component of papuamides A and B, novel cyclodepsipeptides, with anti-HIV and cytotoxic activities. For structural determination and total synthesis of papuamides, all stereoisomers of beta-OMeTyr were stereoselectively prepared from (S)- and (R)-serine, respectively. 相似文献
998.
Fukuhara K Nakanishi I Kansui H Sugiyama E Kimura M Shimada T Urano S Yamaguchi K Miyata N 《Journal of the American Chemical Society》2002,124(21):5952-5953
A catechin analogue in which the geometry was constrained to be planar was synthesized. The planar catechin showed excellent radical-scavenging ability, comparable to that of quercetin, and efficient protection against DNA strand breakage induced by the Fenton reaction. 相似文献
999.
Synthesis of a new class of furan-fused tetracyclic compounds using o-quinodimethane chemistry and investigation of their antiviral Activity 总被引:1,自引:0,他引:1
Matsuya Y Sasaki K Nagaoka M Kakuda H Toyooka N Imanishi N Ochiai H Nemoto H 《The Journal of organic chemistry》2004,69(23):7989-7993
The synthesis and evaluation of antiviral activity of new furan-fused tetracyclic compounds are described. The syntheses were satisfactorily achieved on the basis of o-quinodimethane chemistry, using furan-containing benzocyclobutene derivatives as a substrate, in high generality and stereoselectivity. The various derivatives thus synthesized were examined on their inhibitory activity on virus growth using a hemagglutinin (HA) method, leading to a discovery of promising candidates for new antiviral drugs having high activity and good therapeutic index. 相似文献
1000.
Murata H Takahashi M Namba K Takahashi N Nishide H 《The Journal of organic chemistry》2004,69(3):631-638
A purely organic, high-spin, and durable polyradical molecule was synthesized: It is based on the non-Kekulé- and non-disjoint design of a pi-conjugated poly(1,2-phenylenevinylene) backbone pendantly 4-substituted with multiple robust arylaminium radicals. 4-N,N-Bis(4-methoxy- and -tert-butylphenyl)amino-2-bromostyrene 5 were synthesized and polymerized with a palladium-phosphine catalyst to afford the head-to-tail-linked polyradical precursors (1). Oxidation of 1 with the nitrosonium ion solubilized with a crown ether gave the aminium polyradicals (1(+)()) which were durable (half-life > 1 month) at room temperature in air. A high-spin ground state with an average S = (4.5)/2 for 1a(+) was proved even at room temperature by magnetic susceptibility, magnetization, ESR, and NMR measurements. 相似文献