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101.
102.
Absolute rate constants, k2, for the reaction of OH radicals with 2-methyl-2-butene have been determined over the temperature range 297–425 K using a flash photolysis-resonance fluorescence technique. The Arrhenius expression obtained was k2 = 3.6 × 10?11 exp [(450 ± 400)/RT] cm3 molecule?1 s?1. 相似文献
103.
Philip L. Southwick Klaus M. Hahn Jean Chao Patrick L. Perry Allan S. Wagman Marc Wagner Alan S. Waggoner 《Journal of fluorescence》1995,5(2):231-235
A red fluorescent dye of the oxonol class, bis-[1-(carboxymethyl)barbituric acid-(5)]-pentamethinoxonol, has been synthesized and, in the form of the succinimidyl active ester, has been applied to antibody labeling for application to flow cytometry and to imaging of tissue sections. The new dye, named CMOX (for carboxymethyloxonol), shows maximum excitation at 583 nm and emission at 611 nm, with a quantum yield of 0.2 in aqueous buffer and methanol. Antibodies labeled with the new dye show favorable brightness, photostability, and low levels of nonspecific binding. 相似文献
104.
105.
Raising the pH of an aqueous solution of thorium nitrate results in the precipitation of a hydrated thorium oxide. At room temperature this material does not exhibit any emissive properties, but upon cooling to 77 K a strong green luminescence can be observed. The emission spectrum is fairly broad, and is characterized by an emission lifetime of 125 μs. Calcination of the hydrolysis product produces an anhydrous thorium oxide which is not luminescent at any temperature. Through the production of a series of mixed lanthanide/thorium hydrolysis products, it was established that the luminescent species was a clustered thorium compound. Sensitization of Eu(III) emission by the thorium hydrolysis product was observed. 相似文献
106.
G. W. Gibbons S. W. Hawking Gary T. Horowitz Malcolm J. Perry 《Communications in Mathematical Physics》1983,88(3):295-308
We extend Witten's proof of the positive mass theorem at spacelike infinity to show that the mass is positive for initial data on an asymptotically flat spatial hypersurface Σ which is regular outside an apparent horizonH. In addition, we prove that if a black hole has electromagnetic charge, then the mass is greater than the modulus of the charge. These results are also valid for the Bondi mass at null infinity. Finally, in the case of the Einstein equation with a negative cosmological constant, we show that a suitably defined mass is positive for data on an asymptotically anti-de Sitter surface Σ which is regular outside an apparent horizon. 相似文献
107.
A.J. Perry 《Solid State Communications》1977,24(1):37-39
The intrinsic coercivity of sintered Cr-modified Mn2Sb materials, where the particle size is about the same as the domain wall spacing, is found to be about 700 Oe. This originates in the difficulty of nucleating a domain of reversed magnetization. The coercivity increases initially with temperature, following the variation of anisotropy field. 相似文献
108.
109.
Shirtcliffe NJ McHale G Newton MI Perry CC Roach P 《Chemical communications (Cambridge, England)》2005,(25):3135-3137
Switching between superhydrophobicity and superhydrophilicity in porous materials was predicted theoretically and demonstrated experimentally with the example of thermally induced contact angle change; tunability of this system was also demonstrated. 相似文献
110.
When mixtures of monosubstituted cyclobutadieneiron tricarbonyl complexes and propyne are irradiated, substituted toluenes are obtained. The composition of the isomeric mixture is influenced by the nature of the substituent in the metal complex. Electron-withdrawing groups produce mixtures containing a very large percent of the ortho isomer while electron-releasing groups yield mixtures rich in the para isomer. Complex mixtures of isomeric benzene compounds are obtained when substituted acetylenes are allowed to react with methyl- or isopropylcyclobutadieneiron tricarbonyl. 相似文献