排序方式: 共有23条查询结果,搜索用时 31 毫秒
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Shin-Hwa Wang Tzung-Shin Yeh 《Journal of Mathematical Analysis and Applications》2008,342(2):1175-1191
We study exact multiplicity of positive solutions and the bifurcation curve of the p-Laplacian perturbed Gelfand problem from combustion theory
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We study the exact multiplicity and ordering properties of positive solutions of the p-Laplacian Dirichlet problem
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Fu SC Tzing SH Chen HC Wang YC Ding WH 《Analytical and bioanalytical chemistry》2012,402(6):2209-2216
A simple sample pretreatment technique, dispersive micro-solid phase extraction, was applied for the extraction of N-nitrosodimethylamine (NDMA) and other four N-nitrosamines (NAs) from samples of swimming pool water. The parameters affecting the extraction efficiency were systematically
investigated. The best extraction conditions involved immersing 75 mg of carbon molecular sieve, Carboxen™ 1003 (as an adsorbent),
in a 50-mL water sample (pH 7.0) containing 5% sodium chloride in a sample tube. After 20 min of extraction by vigorous shaking,
the adsorbent was collected on a filter and the NAs desorbed by treatment with 150 μL of dichloromethane. A 10-μL aliquot
was then directly determined by large-volume injection gas chromatography with chemical ionization mass spectrometry using
the selected ion storage mode. The limits of quantitation were <0.9 ng/L. The precision for these analytes, as indicated by
relative standard deviations, were <8% for both intra- and inter-day analyses. Accuracy, expressed as the mean extraction
recovery, was between 62% and 109%. A preliminary analysis of swimming pool water samples revealed that NDMA was present in
the highest concentration, in the range from n.d. to 100 ng/L. 相似文献
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Shin-Hwa Wang 《Journal of Mathematical Analysis and Applications》2004,291(1):128-153
We study the bifurcation diagrams of positive solutions of the two point boundary value problem
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Thermogravimetric analysis (TGA) with nitrogen and oxygen as carrier gas is used for the analysis of cotton lint samples for evaluating their stickiness. The advantage of the low melting point of trehalulose, a commonly found sugar, in the presence of oxygen as carrier gas is used for the evaluation. The oxidation of sugar present in the cotton lint results in increased weight around the melting point, which is proportional to the sugar content. The decomposition of the sugar further results in weight loss. This method is compared with the sticky cotton thermodetector and viscosity method for the estimation of sugar content. Good agreement between the methods suggests the usefulness and simplicity of TGA for estimation of stickiness in cotton. 相似文献
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Tzing SH Ghule A Chang JY Ling YC 《Rapid communications in mass spectrometry : RCM》2003,17(8):811-815
The ion/molecule reactions of nine monosubstituted naphthalene compounds in chemical ionization mass spectrometry (CI-MS) were studied using tetrahydrofuran (THF) as CI reagent. Proton affinity factors, substituent effects and the preferred site of adduct ion attachment were examined. Good correlation was observed between proton affinity and the formation of [M](+*) and [M+H](+) ions. The influence of substituents on protonation and site-specific adduct [M+13](+) and [M+41](+) ion formation is also observed, with the cyano substituent showing the most stable [M+41](+) ion. Collision-activated dissociation experiments were used to characterize the variety of adducts formed under CI conditions, and provided insight into product ion structures and mechanisms of dissociation and condensation during CI-MS/MS. 相似文献
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We study the bifurcation diagrams of (classical) positive solutions u with |u |∞ ∈ (0, ∞) of the p -Laplacian Dirichlet problem (φp (u ′(x)))′ + λfq (u (x))) = 0, –1 ≤ x ≤ 1, u (–1) = 0 = u (1), where p > 1, φp (y) = |y |p –2 y, (φp (u ′))′ is the one-dimensional p -Laplacian, λ > 0 is a bifurcation parameter, and the nonlinearity fq (u) = |1 – u |q is defined on [0, ∞) with constant q > 0. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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We study the bifurcation diagrams of positive solutions of the multiparameter p -Laplacian problem (φ p (u ′(x)))′ + f λ,μ (u (x)) = 0, –1 < x < 1, u (– 1) = u (1) = 0, where p > 1, φ p (y) = |y |p –2 y, (φ p (u ′))′ is the one-dimensional p -Laplacian, f λ,μ (u)= g (u, λ) + h (u, μ), and λ > λ0 and μ > μ0 are two bifurcation parameters, λ0 and μ0 are two given real numbers. Assuming that functions g and h satisfy hypotheses (H1)–(H4), for fixed μ > μ0,we give a classification of totally eight qualitatively different bifurcation diagrams. We prove that, on the (λ, ∥u ∥∞)-plane, each bifurcation diagram consists of exactly one curve which is either a monotone curve or has exactly one turning point where the curve turns to the right. Hence the problem has at most two positive solutions for each λ > λ0. More precisely, we prove the exact multiplicity of positive solutions. In addition, for all p > 1, we give interesting examples which show complete evolution of bifurcation diagrams as μ varies. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献