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171.
在这篇文章里,我们给出了一个具有性质(a)Hausdorff star-Lindel?f空间X使得e(X)=2c,这个例子部分地回答了Matveev的一个问题。 相似文献
172.
173.
本文讨论带Dirichlet边值条件的非线性椭圆型特征值问题,给出了正特征函数存在和唯一的充分必要条件. 相似文献
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175.
Mei Hua LIU Wei Jian XU Xiao Cong XU Yah Bing LU Yah Ru MIAO 《中国化学快报》2006,17(11):1507-1510
The preliminary results for one-pot synthesis of dendronized aromatic polyamides with chloromethyl groups in the periphery by macromonomer approach were reported first time. The GPC analysis of the resulting dendronized polymers has shown typical weight average molecular weight (Mw) of 41554 and a polydispersity of 2.74. 相似文献
176.
A generalized phase-shifting algorithm is implemented in the electron-wave interferometry with a transmission electron microscope, based on simultaneous measurement of the initial phases of the interferograms. The initial phase of each interferogram that has inherent linear carrier fringes is calculated using the Fourier co-efiicients of the interferogram itself corresponding to the carrier-frequency. Taking advantage of this phase-shifting method in both spatial resolution and precision, the phase distribution of a biological weak phase object is successfully measured. This promises to be one of the most spectacular application fields for this new technology. 相似文献
177.
We observed circular white-light dark spatial solitons in photovoltaic self-defocusing LiNbO3:Fe crystal using an ordinary incandescent lamp as light source (a line source) with the filament of the bulb parallel to the crystalline c axis. Besides the above condition, the formation of the elliptic soliton needs an additive condition that the crystalline c axis is parallel to the minor axis of dark elliptic spot. 相似文献
178.
Jia Zhen YANG* Ru Bo ZHANG Institute of Rare Scattered Element Chemistry Liaoning University Shenyang 《中国化学快报》2002,13(5)
This paper reports the EMF(electromotive force) measurements of cell (A) without liquid junction at five temperatures from 278.15 to 318.15 K. Pt|H2(101.325kPa)|HCl(m1),GaCl3(m2),H2O|Ag|AgCl (A) The measurements on the system HCl+GaCl3+H2O was carried out in an appropriate concentration of hydrochloric acid when the concentration of hydrochloric acid is not lower than 0.13 mol/kg the hydrolysis of Ga3+ can be avoided or elimited1. The standard association constant, KAS ,… 相似文献
179.
Colin Ponce Ruipeng Li Christina Mao Panayot Vassilevski 《Numerical Linear Algebra with Applications》2023,30(5):e2501
A common challenge in regression is that for many problems, the degrees of freedom required for a high-quality solution also allows for overfitting. Regularization is a class of strategies that seek to restrict the range of possible solutions so as to discourage overfitting while still enabling good solutions, and different regularization strategies impose different types of restrictions. In this paper, we present a multilevel regularization strategy that constructs and trains a hierarchy of neural networks, each of which has layers that are wider versions of the previous network's layers. We draw intuition and techniques from the field of Algebraic Multigrid (AMG), traditionally used for solving linear and nonlinear systems of equations, and specifically adapt the Full Approximation Scheme (FAS) for nonlinear systems of equations to the problem of deep learning. Training through V-cycles then encourage the neural networks to build a hierarchical understanding of the problem. We refer to this approach as multilevel-in-width to distinguish from prior multilevel works which hierarchically alter the depth of neural networks. The resulting approach is a highly flexible framework that can be applied to a variety of layer types, which we demonstrate with both fully connected and convolutional layers. We experimentally show with PDE regression problems that our multilevel training approach is an effective regularizer, improving the generalize performance of the neural networks studied. 相似文献
180.
Aryne‐Induced Novel Tandem 1,2‐Addition/(3+2) Cycloaddition to Generate Imidazolidines and Pyrrolidines 下载免费PDF全文
Dr. Sharada P. Swain Yi‐Chun Shih Dr. Shwu‐Chen Tsay Joby Jacob Dr. Chun‐Cheng Lin Dr. Kuo Chu Hwang Dr. Jia‐Cherng Horng Prof. Dr. Jih Ru Hwu 《Angewandte Chemie (International ed. in English)》2015,54(34):9926-9930
A new “single‐flask” method was developed for the synthesis of imidazolidines and pyrrolidines with high stereoselectivity. First, a Schiff base was arylated with an aryne. Second, an intramolecular proton transfer took place from the methylene position to the anionic aryne ring. Third, the resultant ylide reacted with a second equivalent of the same Schiff base in situ or an electron‐deficient alkene through a (3+2) cycloaddition. These sequential tandem 1,2‐addition/(3+2) cycloaddition reactions led to the desired heterocycles in 63–88 % yields. 相似文献