共查询到19条相似文献,搜索用时 687 毫秒
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以4种吡啶-4-甲醛缩氨基酸席夫碱配体及其相应的4种金属配合物为研究对象,分别对金黄色葡萄球菌和大肠杆菌2种细菌进行了抑菌实验,测定了最小抑菌浓度(MIC)。应用密度泛函理论(DFT)中的B3LYP方法,从分子前线轨道、键级、电荷分布等方面探讨这类化合物的结构与抑菌效果之间的关系,结果表明C=N健的键级越小,化合物分子的HOMO与LUMO之间的能量差(△E)越小,氮原子上的电子云密度越大,EHOMO能量越高,抑菌效果越好,且抑菌活性部位可能在C=N和吡啶环上。 相似文献
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为满足实验教学和电子爱好者的需要,提出了一种电磁曲射炮实验装置的设计与实现方法;首先给出了基于单片机的电磁曲射炮实验装置整体功能和发射机构分析和计算依据;然后设计了电磁炮子系统的硬件实现电路以及控制方法;采用OPENMV摄像头模块识别标靶方向,利用TFmini激光传感器进行标靶的距离测量,选择CDS5500总线式闭环控制舵机精确控制水平方向角和仰角;设计分段二次多项式拟合仰角和发射炮弹距离的二次函数关系来实现精准发射;该装置具有向固定位置发射、自定义位置发射、自动瞄准模式和弹仓装填等几种工作模式;经测试在射程设定为240 cm时,该装置射击平均误差为1.125 cm;最后通过实验证明了本实验装置的可行性和有效性. 相似文献
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从疑似猪水肿病的30份病料中分离到21株大肠杆菌,经O血清型鉴定,6株为O139,5株为O8,4株为O138,O141、O149、O2各2株,其中O139、O8、O138为优势血清型。用优势血清型菌株筛选出敏感药物,并研制出多价油乳剂灭活苗和高免血清,用多价油乳剂灭活苗免疫仔猪,预防猪水肿病效果良好,而采取多价油乳剂灭活苗预防接种配合活菌制剂益生素的使用,预防效果更佳。使用高免血清是治疗本病的有效方法,而使用高免血清配合敏感抗生素,治疗效果更佳。 相似文献
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The sensitivity data of Staphylococcus aureus and Escherichia coli to a large set of antibiotics have undergone time series procedures of analysis in order to highlight possibly periodical behavior in time. These oscillational patterns have been characterized through the use of FFT and cross-correlational and variance analysis and were proved to be species-specific and drug-independent. S. aureus was shown to have a large period of oscillation (40 months) when compared to E. coli (from 7 to 11 months). A perfect species distinction was only possible through cross correlation. These results may reflect the influence of the local environment, since this finding was not referred to in the literature. 相似文献
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K.-W. Cheng C.-T. Hung M.-H. Chiang F.-N. Hwang J.-S. Wu 《Computer Physics Communications》2011,(1):164-166
Parallel-plate nitrogen dielectric barrier discharge (DBD) driven by a quasi-pulsed power source (60 kHz) is simulated using a fully-implicit 1D self-consistent fluid modeling code. Simulated discharged currents of gap distances (0.5, 0.7 and 1.0 mm) agree very well with measured data; while simulated discharged currents of wider gap distance (1.2 mm) fail to reproduce the measured data. It is found that the discharge mode is homogeneous Townsend-like for the former case; while it is filamentary-like for the latter case based on the experimental observation. These findings demonstrate that previous numerical studies showing mode transition by changing the gap distance may require further investigation. 相似文献
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为了深入研究微腔结构介质阻挡放电(MDBD)的放电机理,搭建了基于介质板表面网格微结构电极装置的实验平台.在分析MDBD微放电过程的基础上,提出了基于电压控制电流源(VCCS)的等效电路来模拟MDBD微放电气隙的动态变化.利用Matlab建立动态仿真模型,并对MDBD的放电特性进行仿真,得到了MDBD放电时的电压电流波形和Lissajous图形.同时,对MDBD的放电特性进行实验研究,并将仿真与实验结果进行对比,验证了MDBD动态仿真模型的准确性.进而利用仿真模型分析计算了不同电压幅值下平均放电功率和放电通道传输电荷量,结果表明,通过仿真计算和实验测量得到的结果及其变化规律是一致的. 相似文献
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同轴圆柱反应器常用于发生介质阻挡放电。实验表明在大气环境的放电中,仅单侧电极有介质的同轴圆柱反应器,放电特性不同于两侧电极都有介质的反应器。前者正反半周放电机理不同,等效电气参数区别很大,不能再用传统的非线性箝位模型作为其等效负载模型。针对此类反应器,提出一种新的半周不对称分段等效模型,并给出了基于李萨如图形的模型参数计算方法,使之能更精确地描述此类介质阻挡放电反应器的电气特性。 相似文献
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Abstract— A numerical method was used to investigate the firing characteristics of the discharge cell in an AC shadow‐mask PDP (SM‐PDP). The firing voltages for the various discharge paths in the addressing and sustaining periods were calculated, and the effects of the metal barrier rib and the dielectric layer in the discharge cell on the firing characteristics were studied. Furthermore, the advantages of the SM‐PDP in terms of the firing characteristics will be discussed. 相似文献
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Thomas Unfer Jean-Pierre Boeuf François Rogier 《Computer Physics Communications》2010,181(2):247-1019
The breakdown of a gas gap at high products of pd (pressure × distance) is a multi-scale phenomenon in both time and space. This is especially true when the plasma is interacting with a gas flow, a problem of considerable recent interest in the context of aerodynamic applications of surface discharges. This paper presents a contribution to the numerical modeling of such discharges. We describe here a new approach for adaptive meshing which is suitable for use with the explicit asynchronous integration scheme described in our previous publication. Rather than relying on a family of nested grids as is commonly done, this technique is based on a single unstructured mesh with possible non-conforming cells at the interface between coarse and fine areas. Substantial computational time saving has been achieved for a surface dielectric barrier discharge configuration of the kind proposed as plasma actuators for flow control. 相似文献