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排序方式: 共有133条查询结果,搜索用时 339 毫秒
1.
Jonn M. Rassias 《数学研究及应用》1987,7(1):77-80
It is well known that F. G. Tricomi (1923) is the originator of the theoryof boundary value problems for mixed type equations by establishing the Thicomi equation: y·uxx+uyy=0 which is hyperbolic for y < 0, elliptic for y=0. and parabolic for y= 0 and then applied it in the theory of transonic flows.Then A.V.Bitsadze together with M. A . Lavrent′ev (1950) established the Bitsadze Lavre nt′ev equation: sgn( y ) ·uxx+uyy=0 where sgn(y) = 1 for y > 0, = -1 for y<0, 0 for y=0 with the discontinuous coefficient sgn( y ) of uxx, while in the case of Tricomi equation the corre sponding coefficient y is continuous. In this paper we establish the mixed Bitsadze Lavrent′ev Tricomi equation. Lu=K(y)·uxx+sgn(x) ·uyy+r(x,y)·u=f(x,y), where the coefficient K=K(y) of uxx is increasing continuous and coefficient M=sgn(x) of uyy discontinuous, r=r(x,y) is once continuously differentiable, f=f(x,y) continuous. Finally we prove the uniqueness of quasi regular solutions and observe that these new results can bbe applied in fluid dynamics. 相似文献
2.
para‐Substituted with electron donating or electron withdrawing groups triphenyl trithioarsenites, (ArS)3As, and octasulfur in refluxing carbon disulfide or chloroform do not give the triaryl tetrathioarsenates, (ArS)3As=S, as was claimed in the literature for tris(4‐methylphenyl) tetrathioarsenate. In some cases oxidative decomposition to As2O3 and disulfides ArSSAr was found. When equivalent amounts of the same esters and octasulfur were heated at 105 or 150 °C no AsV compound was detected or isolated and again some esters decomposed to As2O3 and disulfides. These experiments demonstrated that the aromatic trithioarsenites do not react with octasulfur, probably because they cannot open the octasulfur ring. These esters in solution react with octasulfur in the presence of a catalytic (10—20 mol%) amount of triethylamine giving disulfides, As2O3 and colored solids which could not be characterized. 相似文献
3.
Konstantinos P. Prousalis Gerasimos M. Tsivgoulis 《International journal of environmental analytical chemistry》2013,93(13-14):1065-1078
With the aim of developing polyclonal antibodies binding as many phenyl-N-methylcarbamate insecticides (PNMCs) as possible, IgY antibodies were produced in laying hens. Two haptens (3-(2,6-dimethyl-4-(methylcarbamoyl)phenylaminocarbonyl)propanoic acid and 4-((2,6-dimethyl-4-(methylcarbamoyl)phenylaminocarbonyl)-3,3-dimethyl)butanoic acid) were synthesized preserving the major structural features of PNMCs, by a novel synthetic pathway. These haptens differed only in the spacer arm incorporated. Immunizing antigen and coating antigen were prepared by coupling the first hapten with bovine serum albumin and the second with thyroglobulin, from porcine thyroid glands, respectively. The titre and maturation increase in the developed antibodies, in the egg yolk, were assessed by non-competitive ELISA. Avidity and cross-reactivity of the antibodies with selected pesticides were estimated by means of competitive ELISA. The produced IgYs exhibited a high binding capacity to carbaryl, trimethacarb, metolcarb, aminocarb, and promecarb. These antibodies can be used for immunosorbent preparation for analytical purposes. 相似文献
4.
Imen Ben Atitallah Georgia Antonopoulou Ioanna Ntaikou Amaia Soto Beobide Vassilios Dracopoulos Tahar Mechichi Gerasimos Lyberatos 《Molecules (Basel, Switzerland)》2022,27(4)
The effect of different pretreatment approaches based on alkali (NaOH)/hydrogen peroxide (H2O2) on willow sawdust (WS) biomass, in terms of delignification efficiency, structural changes of lignocellulose and subsequent fermentation toward ethanol, was investigated. Bioethanol production was carried out using the conventional yeast Saccharomyces cerevisiae, as well as three non-conventional yeasts strains, i.e., Pichia stipitis, Pachysolen tannophilus, Wickerhamomyces anomalus X19, separately and in co-cultures. The experimental results showed that a two-stage pretreatment approach (NaOH (0.5% w/v) for 24 h and H2O2 (0.5% v/v) for 24 h) led to higher delignification (38.3 ± 0.1%) and saccharification efficiency (31.7 ± 0.3%) and higher ethanol concentration and yield. Monocultures of S. cerevisiae or W. anomalus X19 and co-cultures with P. stipitis exhibited ethanol yields in the range of 11.67 ± 0.21 to 13.81 ± 0.20 g/100 g total solids (TS). When WS was subjected to H2O2 (0.5% v/v) alone for 24 h, the lowest ethanol yields were observed for all yeast strains, due to the minor impact of this treatment on the main chemical and structural WS characteristics. In order to decide which is the best pretreatment approach, a detailed techno-economical assessment is needed, which will take into account the ethanol yields and the minimum processing cost. 相似文献
5.
Muhammad Aslam NoorThemistocles M. Rassias 《Journal of Mathematical Analysis and Applications》2002,268(1):334-343
In this paper, we consider and analyze a new class of projection methods for solving pseudomonotone general variational inequalities using the Wiener-Hopf equations technique. The modified methods converge for pseudomonotone operators. Our proof of convergence is very simple as compared with other methods. The proposed methods include several known methods as special cases. 相似文献
6.
In this paper, we introduce Pexiderized generalized operators on certain special spaces introduced by Bielecki-Czerwik and
investigate their norms. 相似文献
7.
Our synthetic efforts towards an iNOS (inducible isoform of the nitric oxide synthase) inhibitor led us to the relatively unexplored field of generating and controlling the reactivity of chiral, unsymmetrical thiiranium species. We found that product regiochemistry depends on a tunable equilibrium, the understanding of which proved pivotal in defining a new route to a drug substance. The development of a new amidination method is also discussed. 相似文献
8.
In this paper we obtain a result on Hyers–Ulam stability of the linear functional equation in a single variable $f(\varphi (x)) = g(x) \cdot f(x)$ on a complete metric group. 相似文献
9.
Abstract We have measured the Raman spectra of the quasi-one-dimensional crystal SbSBr as a function of pressure at 295, 70, 37 and 25 K. The pressure coefficients of the observed Raman modes have been determined and used to distinguish inter-from intrachain modes. Spectral features characteristic of the ferroelectric phase have been attributed to impurities or lattice imperfections and not to the presence of the ferroelectric phase, providing indication that the para-to ferroelectric phase transition occurs below 25 K. 相似文献
10.
John Michael Rassias Matina John Rassias 《Journal of Mathematical Analysis and Applications》2003,281(2):516-524
In 1941 Hyers solved the well-known Ulam stability problem for linear mappings. In 1951 Bourgin was the second author to treat this problem for additive mappings. In 1982-1998 Rassias established the Hyers-Ulam stability of linear and nonlinear mappings. In 1983 Skof was the first author to solve the same problem on a restricted domain. In 1998 Jung investigated the Hyers-Ulam stability of more general mappings on restricted domains. In this paper we introduce additive mappings of two forms: of “Jensen” and “Jensen type,” and achieve the Ulam stability of these mappings on restricted domains. Finally, we apply our results to the asymptotic behavior of the functional equations of these types. 相似文献