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141.
Consider the generalized dispersive equation defined by{iδtu+Ф(√-△)u=0,(x,t)∈R^n×R,u(x,0)=f(x),F∈F(R^n),(*)whereФ(√-△)is a pseudo-differential operator with symbolФ(|ζ|).In the present paper,assuming thatФsatisfies suitable growth conditions and the initial data in H^s(R^n),we bound the Hausdorff dimension of the sets on which the pointwise convergence of solutions to the dispersive equations(*)fails.These upper bounds of Hausdorff dimension shall be obtained via the Kolmogorov-Seliverstov-Plessner method. 相似文献
142.
In this paper recurrent neural networks with time-varying delays and continuously distributed delays are considered. Without assuming the global Lipschitz conditions of activation functions, some sufficient conditions for the existence and local exponential stability of the almost periodic solutions are established, which are new and complement previously known results. 相似文献
143.
一个从闭区间到自身的连续映射被称为3阶非单谷Feigenbaum映射,如果它是函数方程f~3(λx)=λf(x)的解.本文讨论了3阶非单谷Feigenbaum映射的拟极限集及其Hausdorff维数.3阶非单谷Feigenbaum映射必然产生混沌,混沌的产生使得拟极限集的存在性问题复杂化.文中采用分形几何中的知识方法证明了此类映射的拟极限集的存在性,并相应的对其Hausdorff维数作出了估计.最后给了一个具体的例子,说明确实存在这样的3阶非单谷Feigenbaum映射. 相似文献
144.
集值映射图的广义相依导数与真有效解的最优性条件 总被引:1,自引:0,他引:1
本文提出了集值映射图的SP-相依导数的概念,利用这个概念,给出了集值向量优化问题两种真有效解的最优性条件. 相似文献
145.
单位球上Bergman空间上的紧算子 总被引:3,自引:0,他引:3
当S满足一些可积条件时,我们证明了Lap(B)(p>1)上的有界算子S是紧的当且仅当S的Berezin变换在单位球B的边界趋近于零. 相似文献
146.
In this paper, to further boost the photocatalytic performance of CdMoO4, Bi3+ was successfully doped into CdMoO4 by a facile microwave hydrothermal method. The Bi-doped CdMoO4 photocatalysts prepared were characterized by Brunauer-Emmett-Teller (BET) method, X-ray diffraction (XRD), UV–Vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), electron spin-resonance (ESR) and surface photovoltage spectroscopy (SPS). The results exhibit that doping Bi3+ into CdMoO4 remarkably boosts the separation rate of photoinduced charge pairs and the specific surface area, decrease the crystal size, narrows the band gap of the CdMoO4 and induces the binding energy shift of Cd, all these advantageous factors result in the promoted photocatalytic performance of CdMoO4. Using rhodamine B (RhB) as model toxic pollutant, the photocatalytic activities of the photocatalysts were evaluated under a 500 W Xe lamp irradiation. When the molar ratio of Bi/Cd is 0.2%, Bi-CdMoO4 prepared displays the best photocatalytic performance, the photocatalytic performance of the 0.2% sample is more than twice of that of the reference CdMoO4. 相似文献
147.
1 INTRODUCTION As is widely known, PCDFs together with poly- chlorinated dibenzo-p-dioxins (PCDDs) and poly- chlorinated biphenyls (PCBs) have been included in many blacklists, such as “persistent organic pol- lutants (POPs)” and suspected “environmental en- docrine disruptors (EEDs)”. This is because PC- DFs are chemically and thermally stable and com- plex PCDF mixtures are generally resistant to bio- degradation. Although the concentration of these chemicals is quite low o… 相似文献
148.
《Journal of organometallic chemistry》2005,690(24-25):5900-5911
{[2-(Dialkylamino)ethenyl]ethoxycarbene}chromium complexes 4 have been made available from lithiated terminal alkynes, hexacarbonylchromium, triethyloxonium tetrafluoroborate and secondary amines in a one-pot operation, in good to excellent yields. Reactions of these complexes with alkynes afford 5-dialkylamino-3-ethoxycyclopentadienes 8 with excellent chemoselectivity. From cyclopentadienes of type 8, angular and linear triquinanes, di- and triannelated benzene derivatives 24/25, steroid-like skeletons 30/31, and hexacycles 32/33 can be obtained with great facility. In addition, otherwise not easily accessible cyclopenta[b]pyrans 42/43 and novel spiro[4.4]nonatrienes 52/53 can be prepared in single operational steps from complexes 4 and terminal alkynes via [3 + 2 + 2 + 1] and [3 + 2 + 2 + 2] cocyclizations incorporating two and three alkyne units, respectively. Upon heating simple Fischer carbene complexes of type 2 with methylenecyclopropanes 64, cyclopentenones 65 are formed by formal [4 + 1] cycloadditions. New carbenemetal complexes which have different chemical reactivities can be formed in situ by transmetallation from the corresponding carbenechromium complexes. Various cyclopentenone, cyclopentene and cycloheptanone derivatives are easily accessible from these new carbenemetal (nickel and rhodium) complexes and an alkyne or an allene. 相似文献
149.
150.
《中国化学快报》2020,31(12):3205-3208
Selenization of Fe2O3 with NaHSe led to Se/Fe3O4. The unexpected generation of Fe3O4 attributed to the reduction conditions of the reaction, and the resulted magnetic features of the material facilitated its separation in practical applications. Owning to the synergistic effect of Se with Fe, the material was especially active to catalyze the oxidative C=C scission using O2 as mild oxidant. The technique has been successfully applied in polyene degradation project, which is of profound practical values for the treatment of the polyene pigment pollution and may be applied in the food and pharmaceutical industry. 相似文献