Recursive algorithms for deriving bandpass or band-rejection filters from lowpass filters

Two recursive algorithms are presented for calculating the coefficients of a bandpass transfer function, given the lowpass prototype transfer function. In both cases, the method is general, valid for prototypes having both poles and zeros, and provides excellent accuracy. Moreover, it is shown that the coefficients of band-rejection filters can be derived by using either algorithm.<>     

凝结水精处理专题调研报告

凝结水的品质是影响热力系统腐蚀与结垢的主要因素之一。通过调研火力发电厂的水化学工况的特点、凝结水处理系统的作用以及国内的实际情况 ,提出凝结水处理系统的设计要求。     

核探针技术的初步应用

使用新建成的核探针开展了阿米巴细胞中微量元素锌的含量及其分布的观察;锰矿物中微米级矿粒和矿物相的分析;深海锰结核内微米级层状结构的分析;反球化元素对球墨铸铁的影响以及微量元素的偏析造成不锈钢零件局域性断裂的研究。     

Vesicular transport: implications for cell polarity

In polarized cells intracellular sorting of plasma membrane proteins occurs to a large extent at the trans-Golgi network, giving rise to vesicles destined for distinct plasma membrane domains. This review discusses the several pathways, both direct and indirect, which lead to protein incorporation into the correct cell surface, as well as the mechanisms involved. Proteins contain signals which direct their incorporation into the distinct vesicles destined for plasma membrane microdomains. Specific coat proteins are involved in vesicle assembly and are likely to play a role in the generation of discrete vesicle populations. Molecules involved in vesicle docking and fusion may also add specificity to the targeting process.     

Mechanically driven syntheses of carbides and silcides

Most metal carbides or slicides may be synthesized at room temperature, by ball milling mixtures of elemental powders for some tens of hours with a vibratory mill. Both stable and metastable compounds containing a high density of defects can be obtained. In general, phases stable at low temperatures are synthesized. This observation allows us to confirm recent estimations for the maximum temperature (600 K) attained in these powders during mechanical alloying. Exceptions are found for some MSi₂ suicides with M = titanium, iron or molybdenum for which both low- and high-temperature phases are formed.     

基于代价敏感Faster R-CNN的脑CT影像出血诊断方法

脑出血是一种在患者颅内突然发生的重急症,常伴随有强烈的症状和较高致死率,基于脑CT影像对脑出血进行自动化快速诊断具有重要意义。其中,临床上有效应用的实现不仅要求诊断结果的准确性、诊断速度和结果解释能力,尤其要重视出血漏检情形。因此本文提出代价敏感的Faster R-CNN模型,通过自动调节模型中锚的训练样本比例以及在损失函数中引入衡量阳性样本重要性的超参数等方式,更多地关注阳性样本和漏检情形提升检测效果,最后通过定位的具体目标区域来诊断脑内出血情况。经多次实验选择性能最优的网络结构和合适的超参数,利用多项指标度量最终模型的检测和诊断效果。实验结果表明,代价敏感的Faster R-CNN方法能够从减少漏检的角度上更好地识别出血区域,进而提高不平衡代价下的脑出血诊断效果。     

基于核方法的敏感信息过滤的研究

在深入分析敏感信息过滤任务的特点和难点的基础上,针对现有一般的信息过滤方法的不足,提出了一种利用敏感词的组合信息来改进过滤效果的思想.进而,研究了在核方法的框架下特征共现行为建模的原则并提出了复合ANOVA核来刻画特征组合行为.通过真实信息过滤环境中的测试评估,显示了此敏感信息过滤方法的有效性.     

Synthesis, characterization and electrochemical properties of 4.8 V LiNi0.5Mn1.5O4 cathode material in lithium-ion batteries

In this work the synthesis of a nickel doped cubic manganese spinel has been studied for application as cathode material in secondary lithium batteries. Six different experimental approaches have been tested in order to carry out a screening of the various possible synthetic routes. The used synthetic strategies were wet chemistry (WC), solid state (SS), combustion synthesis (CS), cellulose-based sol-gel synthesis (SG-C), ascorbic acid-based sol-gel synthesis (SG-AA) and resorcinol/formaldehyde-based sol-gel synthesis (SG-RF). The goal of our study is to obtain insights about how the synthesis conditions can be modified in order to achieve a material with improved electrochemical performances in such devices, especially in high current operating regimes. The synthesized materials have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), atomic absorption, inductively coupled plasma (ICP-MS) atomic emission spectroscopy, surface area measurements and tested as high voltage cathodes in Li-ion electrochemical devices.     

Catalytic wall reactor: Catalytic coatings of stainless steel by VOx/TiO2 and Co/SiO2 catalysts

Catalytic wall (structured) reactors and structured supports are suitable to study the catalytic properties of nanosized materials. The coating of metallic (aluminum and stainless steel) plates by thin layers of active phase is presented in two cases, VO_x/TiO₂ and Co/SiO₂, catalysts used in the oxidative dehydrogenation (ODH) of propane and in Fischer–Tropsch synthesis (FTS) of clean fuels, respectively. The preparation of coated plates and their characterisation by various methods of physicochemical analysis are described. Both chemical and physical methods were used for coating. VO_x/TiO₂ layers were obtained by grafting of Ti (on Al or stainless-steel plates) and V (on TiO₂) alkoxides and use of sol–gel media or suspension. A silica primer was deposited (on stainless-steel plate) by plasma-assisted chemical vapour deposition (PACVD) onto which Co oxide and silica were coprecipitated from sol–gel. The catalytic experiments in the respective reactions were carried out in special plate reactors and compared with those of catalytic powders. The study shows that the coating of a metallic substrate by a catalyst is not straightforward and requires specific studies dealing with both chemistry (chemical affinity between substrate and catalytic layers) and catalytic engineering (catalytic performance in taylor-made reactors).