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861.
Yao Chun-Hsu Chang Tung-Hao Tsai Min-Jia Lai Yuan-Chun Chen Yi-An Chang Yuan-Jen Chen Chin-Hsing 《Journal of Radioanalytical and Nuclear Chemistry》2017,311(2):1277-1286
Volumetric modulated arc therapy (VMAT) was developed to shorten treatment time and increase target conformance. However, a true three-dimensional (3D) gel dosimeter is needed for dose verification. In this study, two clinic cases were adopted: a simple case of lung cancer and a complex case of larynx cancer. For each clinic case, two treatment plans were generated for the same planning target volume using VMAT and intensity modulated radiation therapy calculation software packages. An N-isopropylacrylamide (NIPAM) polymer gel dosimeter was used for 3D dose verification. In addition, the dose characteristics of the NIPAM gel dosimeter were investigated for the two clinic cases.
相似文献862.
为了合成selaginellin家族天然产物,我们开发了炔锂和对亚甲基苯醌的1,6-加成反应。研究了此反应的反应条件及底物适用范围和限制。结果表明,对亚甲基苯醌苯环上的取代基对反应速率和产率有显著的影响:吸电子基团增加其亲电性,使反应变快,并且可以得到较高的产率;与此相反,给电子基团则降低了对亚甲基苯醌的亲电性,反应变慢,并且表现出可逆性,产率变低。端炔对反应影响很小,均能得到高产率的产物。本方法可用于快速构建selaginellin家族天然产物的骨架结构。 相似文献
863.
WANG Bo LIU ZhengWei HAN YunKun LEI ZhenXin LUO YangPing & HAN ZhanWen National Astronomical Observatories/Yunnan Observatory Chinese Academy of Sciences Kunming China Key Laboratory for the Structure Evolution of Celestial Objects Graduate University of Chinese Academy of Sciences Beijing 《中国科学:物理学 力学 天文学(英文版)》2010,(3)
Type Ia supernovae (SNe Ia) play an important role in diverse areas of astrophysics, from the chemical evolution of galaxies to observational cosmology. However, the nature of the progenitors of SNe Ia is still unclear. In this paper, according to a detailed binary population synthesis study, we obtained SN Ia birthrates and delay times from different progenitor models, and compared them with observations. We find that the Galactic SN Ia birthrate from the double-degenerate (DD) model is close to those infe... 相似文献
864.
Nonlinear Dynamics - This paper investigates the generation of some novel bursting patterns in active control oscillator with multiple time delays. We present the bursting patterns, including... 相似文献
865.
In this Letter, self-organization of directed networks is surveyed. Inspired from the results in neural networks research, we propose an asymmetric coupling scheme with simple edge deleting rules. Results show that all-to-all networks can be organized into scale-free networks with feed-forward structures. Corresponding analysis is also given. 相似文献
866.
867.
This study extends the upstream flux‐splitting finite‐volume (UFF) scheme to shallow water equations with source terms. Coupling the hydrostatic reconstruction method (HRM) with the UFF scheme achieves a resultant numerical scheme that adequately balances flux gradients and source terms. The proposed scheme is validated in three benchmark problems and applied to flood flows in the natural/irregular river with bridge pier obstructions. The results of the simulations are in satisfactory agreement with the available analytical solutions, experimental data and field measurements. Comparisons of the present results with those obtained by the surface gradient method (SGM) demonstrate the superior stability and higher accuracy of the HRM. The stability test results also show that the HRM requires less CPU time (up to 60%) than the SGM. The proposed well‐balanced UFF scheme is accurate, stable and efficient to solve flow problems involving irregular bed topography. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
868.
Xavier L��pez Pere Mir�� Jorge J. Carb�� Antonio Rodr��guez-Fortea Carles Bo Josep M. Poblet 《Theoretical chemistry accounts》2011,128(4-6):393-404
Computational chemistry applied to the study of polyoxometalates has achieved its maturity in the last years. During two decades, important advances have been made using theoretical tools in the comprehension and interpretation of many relevant issues. In the present mini-review, we want to stress that different techniques have been incorporated to the routine of computation: from the very first Hartree?CFock LCAO-SCF calculation on the decavanadate anion, followed by numerous density functional theory?Cbased studies on increasingly complex systems, also applying correlated ab initio techniques for magnetism and, more recently, using molecular dynamics to analyse properties in liquid media, the information provided by computational chemistry gets more and more relevant. 相似文献
869.
870.
Bo Deng 《Journal of Differential Equations》2011,250(6):2940-2957
For a class of circuit models for neurons, it has been shown that the transmembrane electrical potentials in spike bursts have an inverse correlation with the intra-cellular energy conversion: the fewer spikes per burst the more energetic each spike is. Here we demonstrate that as the per-spike energy goes down to zero, a universal constant to the bifurcation of spike-bursts emerges in a similar way as Feigenbaum's constant does to the period-doubling bifurcation to chaos generation, and the new universal constant is the first natural number 1. 相似文献