排序方式: 共有59条查询结果,搜索用时 9 毫秒
41.
Xiaofu He Wei Liu Xuzhou Li Qingli Li Feng Liu Virginia A. Rauh Dazhi Yin Ravi Bansal Yunsuo Duan Alayar Kangarlu Bradley S. Peterson Dongrong Xu 《Magnetic resonance imaging》2014
Diffusion tensor imaging (DTI) data often suffer from artifacts caused by motion. These artifacts are especially severe in DTI data from infants, and implementing tight quality controls is therefore imperative for DTI studies of infants. Currently, routine procedures for quality assurance of DTI data involve the slice-wise visual inspection of color-encoded, fractional anisotropy (CFA) images. Such procedures often yield inconsistent results across different data sets, across different operators who are examining those data sets, and sometimes even across time when the same operator inspects the same data set on two different occasions. We propose a more consistent, reliable, and effective method to evaluate the quality of CFA images automatically using their color cast, which is calculated on the distribution statistics of the 2D histogram in the color space as defined by the International Commission on Illumination (CIE) on lightness and a and b (LAB) for the color-opponent dimensions (also known as the CIELAB color space) of the images. Experimental results using DTI data acquired from neonates verified that this proposed method is rapid and accurate. The method thus provides a new tool for real-time quality assurance for DTI data. 相似文献
42.
MA Juan & GAO QingYu College of Chemical Engineering China University of Mining Technology Xuzhou China 《中国科学B辑(英文版)》2011,(9)
The control effect of recycled noise,generated by the superposition of a primary Gaussian noise source and a secondary source with a constant delay,has been studied in an excitable FitzHugh-Nagumo system.We mainly focus on the performance of noise-induced spike and coherence resonance in a parameter region sub-threshold to supercritical Hopf bifurcation.For fixed noise intensity,simulations show that the coherence(quantitatively measured by R,which is defined as the mean value of the spike interval time T n... 相似文献
43.
Dr. Guangfeng Li Dr. Zhixuan Zhou Chang Yuan Zhewen Guo Yuhang Liu Dr. Dong Zhao Dr. Kai Liu Jun Zhao Prof. Hongwei Tan Prof. Xuzhou Yan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(25):10099-10103
Herein, the trackable supramolecular transformation of a two-component molecular cage to a three-component cage through supramolecular fusion with another two-component molecular square is described. The use of tetraphenylethene (TPE), a chromophore with aggregation-induced emission (AIE) character, as a component for the molecular cages enables facile fluorescence monitoring of the transformation process: while both cages exhibit fluorescence emission via the restriction of intramolecular motion of the TPE motif, the interactions between TPE and 4,4′-bipyridine introduced in the supramolecular fusion process result in partial fluorescence quenching and shifts in the emission maximum. This study provides a simple and efficient approach towards complex supramolecular cages with emergent functions and demonstrates that AIE features could provide unique opportunities for the characterization of complex, dynamic supramolecular transformation processes. 相似文献
44.
RbⅧ—NbⅪ离子n=4complex跃迁谱线、波长和振子强度 总被引:4,自引:0,他引:4
用HXR方法计算了类锌等电子序列RbⅧ-NbⅫ离子n=4complex组态能级,通过对各能级值沿等电子序列的变化规律分析,找出了ⅦE随Zc变化的一种新的拟合公式,运用此公式和我们自己设计的FOR-TRAN程序对上述组态各能级值进行了系统的拟合计算,给出了4s^2-4s4p,4s4p-4s4d跃迁谱线波长和相应的振子强度。 相似文献
45.
46.
Zhaoming Zhang Lin Cheng Jun Zhao Lei Wang Kai Liu Wei Yu Xuzhou Yan 《Angewandte Chemie (International ed. in English)》2020,59(29):12139-12146
Nature has engineered delicate synergistic covalent and supramolecular polymers (CSPs) to achieve advanced life functions, such as the thin filaments that assist in muscle contraction. Constructing artificial synergistic CSP materials with bioinspired mechanically adaptive features, however, represents a challenging goal. Here, we report an artificial CSP system to illustrate the integration of a covalent polymer (CP) and a supramolecular polymer (SP) in a synergistic fashion, along with the emergence of notable mechanical and dynamic properties which are unattainable when the two polymers are formed individually. The synergistic effect relies on the peculiar network structures of the SP and CPs, which endow the resultant CSPs with overall improved mechanical performance in terms of the stiffness, strength, stretchability, toughness, and elastic recovery. Moreover, the dynamic properties of the SP, including self‐healing, stimuli‐responsiveness, and reprocessing, are also retained in the CSPs, thus leading to their application as programmable and tunable materials. 相似文献
47.
Host–guest complexation between a dibenzo-24-crown-8-based cryptand and a paraquat derivative was studied. Subsequently, two novel [2]rotaxanes based on the dibenzo-24-crown-8-based cryptand/paraquat recognition motif were prepared by threading-followed-by-stoppering method and single-pot method, respectively. The obtained mechanically interlocked structures were confirmed by 1H NMR, 13C NMR, 2D NMR, and ESI-MS. 相似文献
48.
设G是一个图,若对于图G的任一条边e,G-e都存在一个分数k-因子,则称G是一个分数k-消去图.若k=2,则称分数k-消去图为分数2-消去图.本文证明了当bind(G)≥2,并且δ(G)≥3时,G是分数2-消去图. 相似文献
49.
WANG KeQuan & FAN QiuBo College of Mathematics Physics Xuzhou Institute of Technology Xuzhou China 《中国科学G辑(英文版)》2009,52(9):1307-1312
We seek to analyze a three-level cascade laser with a pair of nonlinearly coupled waveguides inside the cavity. Applying the
pertinent master equation, we investigate the squeezing and entanglement properties intracavity produced by our system. It
is shown that with the help of nonlinearly coupled waveguides highly squeezed as well as macroscopic entangled light with
high intensity can be achieved.
Supported by the Natural Science Youth Teacher Foundation of Xuzhou Institute of Technology (Grant No. XKY2007317) 相似文献
50.
关于长方矩阵加权Drazin逆的一种分裂法 总被引:4,自引:0,他引:4
本文给出了求解长方矩阵加W-权Drazin逆的一种分裂法及其相应的迭代法;并且讨论了迭代法收敛到加W-权Drazin逆的充分必要条件。对迭代法半收敛的情形,本文亦作了讨论。 相似文献