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41.
Sedigheh Borhani Seyed Gholamreza Etemad Seyed Abdolkarim Hosseini Ravandi 《Heat and Mass Transfer》2011,47(7):807-811
In this study a non-conventional electrospinning technique was designed for the production of high bulky polyacrylonitrile
(PAN) nanofiber mats. Optimum nanofiber mats are achieved with 15 wt.% solution of PAN in dimethylformamide. Such mats result
in a bulk porosity which is as high as 99.9 and a density as low as 0.84 × 10−3 g/cm3. The effect of the porosity of nanofiber mats on the air permeability and coupled heat and moisture transfer of fibers was
investigated. Based on the results, high bulky nanofiber mats possess high heat and moisture transfer. Experimental data reveal
that upon a slight decrease in the bulk porosity, air permeability and heat transfer decrease noticeably, while moisture transfer
variation is low. 相似文献
42.
A novel synthesis of polysubstituted pyrazoles 3a-d, pyrimidines 4a-f and quinolines 5a-c via the reaction of α,α-oxoketene dithioacetals 2a-c with hydrazine hydrate, malonohydrazide, urea, thiourea and aniline is reported and the synthetic potential of the method is demonstrated. The structure of the new compounds was established upon their elemental analysis, IR, 1H NMR and 13C NMR. 相似文献
43.
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45.
Eman S. Al‐Aidarous Ebraheem O. Alzahrani Hitoshi Ishii Arshad M. M. Younas 《Mathematische Nachrichten》2014,287(14-15):1563-1588
We study the dynamical boundary value problem for Hamilton‐Jacobi equations of the eikonal type with a small parameter. We establish two results concerning the asymptotic behavior of solutions of the Hamilton‐Jacobi equations: one concerns with the convergence of solutions as the parameter goes to zero and the other with the large‐time asymptotics of solutions of the limit equation. 相似文献
46.
Friedel–Crafts acylation of benzene derivatives such as anisole, toluene, and xylene has been successively carried out using silver nitrate as the catalyst in the presence of an eco friendly solvent (ethyl alcohol). Both benzoyl chloride and acetyl chloride reacted smoothly under the conditions to afford the corresponding ketones in good yield.
47.
Ebraheem Abdu Musad 《合成通讯》2013,43(23):3569-3576
Some new 3,4,5-substituted isoxazoles, 3,4,5 and 1,3,4,5-substituted pyrazoles were prepared by reaction of α,α-oxoketen dithioacetals with hydroxylamine hydrochloride; phenyl hydrazine and hydrazine hydrate respectively under solvothermal conditions involving an ecofriendly method without any environmental pollution. The yields are in the range of 71–91%. The structure of the new compounds were established upon their elemental analysis, IR, 1H NMR, and 13C NMR. 相似文献
48.
‘Local’ and ‘nonlocal’ contributions to σd are calculated by INDO molecular orbital methods. It is demonstrated, by means of Pople's approach5 using ‘gauge dependent’ atomic orbitals, that σ is effectively constant for C, N, O or F in a number of chemically different environments and that σ is negligible. The use of Flygare's method12 produces a significant and variable ‘nonlocal’ contribution, which renders σd in this formulation comparable to the gauge dependent term in Ramsey's expression. 相似文献
49.
In this paper we prove that an n-dimensional compact homogeneous Riemannian manifold isometrically immersed in the hyperbolic space Hn+1 is isometric to a sphere.AMS Subject Classification (1990): 53A07, 53C42, 57S15 相似文献
50.
Low temperature specific heat measurements on (TTF) (TCNQ) are reported. The Debye temperature is 89.5 K. No term linear in temperature is observed, and comparison with other data indicates the low temperature phase is that of a small band gap non-magnetic semiconductor. 相似文献