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采用非线性动力学方法研究脑精神疾病是近年来国内外学者研究的热点和趋势.针对脑精神疾病的研究和诊断中缺少客观有效的量化参数和量化指标的状况,提出了一种根据对时间序列功率谱划分而定义的谱熵,然后用其计算和分析脑电信号谱熵的方法.通过数据仿真试验证明该谱熵和信号活跃性之间存在正相关关系.基于这种相关性,应用该方法对抑郁症患者和正常对照组的脑电信号功率谱熵进行了数值计算,然后进行了分析对比和统计检验.实验结果表明:抑郁症患者脑电信号的功率谱熵在部分脑区显著弱于正常健康人.证明该谱熵能够表征大脑电生理活动状况,提供反映其活动性强弱的信息,可以作为度量大脑电生理活动性的一个参数.这对于能否将该功率谱熵作为诊断脑精神疾病的物理参数具有积极意义. 相似文献
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von-Neumann正则环与左SF-环 总被引:6,自引:0,他引:6
环R称为左SF-环,如果每个单左R-模是平坦的.众所周知,Von-Neumann正则环是SF-环,但SF-环是否是正则环至今仍是公开问题,本文主要研究左SF-环是正则环的条件,证明了:如果R是左SF-环且R的每个极大左(右)理想是广义弱理想,那么R是强正则环.并且推广了Rege[3]中的相应结果. 相似文献
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A ring R is called a left (right) SF-ring if all simple left (right) R-modules are flat. It is known that von Neumann regular rings are left and right SF-rings. In this paper, we study the regularity of right SF-rings and prove that if R is a right SF-ring whose all maximal (essential) right ideals are GW-ideals, then R is regular. 相似文献
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Let E/F be a Galois extension of number fields with Galois group G=Gal(E/F), and let p be a prime not dividing #G. In this paper, using character theory of finite groups, we obtain the upper bound of #K2OE if the group K2OE is cyclic, and prove some results on the divisibility of the p-rank of the tame kernel K2OE, where E/F is not necessarily abelian. In particular, in the case of G=Cn, Dn, A4, we easily get some results on the divisibility of the p-rank of the tame kernel K2OE by the character table. Let E/Q be a normal extension with Galois group Dl, where l is an odd prime, and F/Q a non-normal subextension with degree l. As an application, we show that f|p-rank K2OF, where f is the smallest positive integer such that pf≡±1(mod l). 相似文献
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设计并合成了12个亚乙基桥联双茚类锆、铪配合物meso-/rac-1~7[ansa-C2H4-(3-R-4,7-Me2-C9H3)2MCl2:M=Zr R=nBu (meso-/rac-1),iPr (meso-2),CH2Cy (meso-/rac-3),Bn (meso-/rac-4),CH2C6H4(4-CH3)(meso-/rac-5);M=Hf,R=CH2C6H4(4-CH3)(meso-/rac-7);ansa-C2H4-{2-Me-3-Bn-5,6-[1,3-(CH2)3]C9 相似文献
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To obtain useful information for identifying inhibitors of urate transporter 1(URAT1), three-dimensional quantitative structure-activity relationship(3 D-QSAR) analysis was conducted for a series of lesinurad analogs via Topomer comparative molecular field analysis(CoMFA). A 3 D-QSAR model was established using a training set of 51 compounds and externally validated with a test set of 17 compounds. The Topomer CoMFA model obtained(q^2 = 0.976, r2 = 0.990) was robust and satisfactory. Subsequently, seven compounds with significant URAT1 inhibitory activity were designed according to the contour maps produced by the Topomer CoMFA model. 相似文献
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以CuC2O4纳米微球为模板,通过水热法在120 ℃、1 h时成功合成了一维CuC2O4/ZnO异质结构。 采用热重分析(TGA)、场发射扫描电子显微镜(FE-SEM)、能量散射X射线谱(EDX)、透射电子显微镜(TEM)和X射线粉末衍射(XRD)等测试技术对产物的结构和形貌进行了表征。 结果表明,所得产物为一维CuC2O4/ZnO纳米棒束,长约1 μm,直径约500 nm。 每个棒束由许多纳米棒沿同一方向组装而成。 TEM照片和EDX光谱表明,CuC2O4和ZnO形成了均匀的异质结构。 相似文献