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71.
Testing the validity of the conditional capital asset pricing model(CAPM) is a puzzle in the finance literatureLewellen and Nagel[14]find that the variation in betas and in the equity premium would have to be implausibly large to explain important asset-pricing anomaliesUnfortunately, they do not provide a rigorous test statisticBased on a simulation study, the method proposed in Lewellen and Nagel[14]tends to reject the null too frequently.We develop a new test procedure and derive its limiting distribution under the null hypothesis.Also, we provide a Bootstrap approach to the testing procedure to gain a good finite sample performanceBoth simulations and empirical studies show that our test is necessary for making correct inferences with the conditional CAPM. 相似文献
72.
Tetrabutylammonium fluoride(TBAF) effectively facilitated a denitrative substitution reaction of electron-deficient nitroarenes with phenylthiotrimethylsilane(PhSTMS) under mild and base-free neutral conditions at room temperature,providing a practical and efficient synthesis of useful unsymmetrical diaryl thioethers.Nitroarenes bearing ortho-and para-positioned electron-withdrawing groups are the most reactive substrates,indicating that this reaction most possibly proceeded via the nucleophilic aromatic substitution(S_NAr) mechanism. 相似文献
73.
Achieving higher performances without an external curing agent in natural magnolol-based epoxy resin
Qi Cao Zhihuan Weng Yu Qi Jiahui Li Wentao Liu Chengde Liu Shouhai Zhang Zhiyong Wei Yousi Chen Xigao Jian 《中国化学快报》2022,(4):2195-2199
Bio-based epoxy thermoset prepared from renewable biomass raw materials can alleviate fossil energy crisis and reduce environmental pollution,which satisfies the needs of sustainable social development.In this study,a bio-based epoxy thermoset precursor(MGOL-EP) was synthesized from a naturally occurring magnolol through a facile and efficient one-step process.And the fully bio-based epoxy thermoset(MGOL-EP-SC) was obtained by self-curing without adding any other hardener.MGOL-EP-SC revealed an ... 相似文献
74.
Aggregation-induced emission(AIE) based luminescent materials are generating intensive interest due to their unique fluorescence in the aggregation state. Herein we report a strategy of dynamic covalent chemistry(DCC) controlled AIE luminogens for the regulation of multicolor emission in reversible covalent polymer networks. Tetraphenylethene derived ring-chain tautomers were prepared, and the emission was readily controlled through multimode, such as changing the solvent, adding the base, and d... 相似文献
75.
Qifei Li Xiangxiang Ye Hong Yu Chengfeng Du Wenping Sun Weiling Liu Hongge Pan Xianhong Rui 《中国化学快报》2022,33(5):2663-2668
Zinc-ion batteries(ZIBs), in particular quasi-solid-state ZIBs, occupy a crucial position in the field of energy storage devices owing to the superiorities of abundant zinc reserve, low cost, high safety and high theoretical capacity of zinc anode. However, as divalent Zn2+ions experience strong electrostatic interactions when intercalating into the cathode materials, which poses challenges to the structural stability and higher demand in Zn2+ions diffusion kinetics of the ... 相似文献
76.
We present a comparative study of the application of a recently introduced heuristic algorithm to the optimization of transport on three major types of complex networks. The algorithm balances network traffic iteratively by minimizing the maximum node betweenness with as little path lengthening as possible. We show that by using this optimal routing, a network can sustain significantly higher traffic without jamming than in the case of shortest path routing. A formula is proved and tested with numerical simulation that allows quick computation of the average number of hops along the path and of the average travel times once the betweennesses of the nodes are computed. Using this formula, we show that routing optimization preserves the small-world character exhibited by networks under shortest path routing, and that it significantly reduces the average travel time on congested networks with only a negligible increase in the average travel time at low loads. Finally, we study the correlation between the weights of the links in the case of optimal routing and the betweennesses of the nodes connected by them. 相似文献
77.
The recent development of selective oxidation of aromatic sulfides with molecular oxygen was highlighted. The sulfoxides and sulfones could be obtained by simply switching the reaction media, i.e., bis(2-butoxyethyl)ether (BBE) or poly(ethylene glycol)dimethyl ether (PEGDME). The application of the high-boiling-point polyether as an initiator and green media can eliminate the need of large quantities of additives and volatile solvents. This strategy represents an economic and eco-friendly method that could find potential applications. 相似文献
78.
Some novel cycloaddition reactions based on benzyne and olefins have been developed.These reactions were performed in the absence of a transition metal catalyst,and they displayed good yields.These cycloaddition reactions of benzyne with olefins provide effective routes for synthesizing benzocyclobutenes,biaryl compounds and 9,10-dihydrophenanthrene derivatives. 相似文献
79.
Zonglin Li Jianjun Chen Yu Xie Junjie Wen Huiling Weng Mingxue Wang Jingyi Zhang Jinyan Cao Guocai Tian Qiulin Zhang Ping Ning 《Journal of Energy Chemistry》2024,(4):213-225
An in-depth mechanism in zonal activation of CO2 and H2 molecular over dual-active sites has not been revealed yet.Here,Ni-Co-MgO was rationally constructed to elucidate the CO2 methanation mechanism.The abundant surface nickel and cobalt components as active sites led to strong Ni-Co interaction with charge transfer from nickel to cobalt.Notably,electron-enriched Coδ- species participated in efficient chemisorption and activation of CO2 to ... 相似文献
80.
Hydrodynamic instabilities induced by a shock wave can be observed in both natural phenomena and engineering applications,and are frequently employed to study gas dynamics, vortex dynamics, and turbulence. Controlling these instabilities is very desirable, but remains a challenge in applications such as inertial confinement fusion. The field of “shock-gas-layer interaction” has experienced rapid development, driven by advances in experimental and numerical techniques as well as theoretical under... 相似文献