EMAP: An efficient mutual authentication protocol for passive RFID tags

Radio frequency identification (RFID) system is a contactless automatic identification system, which uses small and low cost RFID tags. The primary problem of current security and privacy preserving schemes is that, in order to identify only one single tag, these schemes require a linear computational complexity on the server side. We propose an efficient mutual authentication protocol for passive RFID tags that provides confidentiality, untraceability, mutual authentication, and efficiency. The proposed protocol shifts the heavy burden of asymmetric encryption and decryption operations on the more powerful server side and only leaves lightweight hash operation on tag side. It is also efficient in terms of time complexity, space complexity, and communication cost, which are very important for practical large-scale RFID applications.     

食品中单增李斯特氏菌检测PCR-免疫胶体金 试纸条方法的建立

目的 建立食品中单核增生李斯特氏菌快速检测PCR-免疫胶体金试纸条法。方法 通过设计特异性引物建立单增李斯特氏菌检测PCR方法并使用免疫胶体金技术建立PCR产物快速检测试纸条; 用试验菌株检测PCR-免疫胶体金试纸条方法的检测特异度与敏感度。使用新建方法对市售肉制品和乳制品中单核增生李斯特氏菌进行检测, 验证该方法在食品检测中的可行性。结果 PCR-免疫胶体金法具有良好的特异度, 敏感度比标准琼脂糖凝胶电泳法高100倍。采集乳品样品131份, 阳性样品1份, 检出率1.53%; 肉制品224份, 阳性样品4份, 检测率1.79%。结论 建立的单增李斯特氏菌检测PCR-免疫胶体金试纸条法特异度好, 敏感度高, 适用于食品中单增李斯特氏菌的检测。     

高温高盐油藏用调驱体系的研究进展

综述了聚合物冻胶、无机凝胶、无机盐沉淀、预交联冻胶颗粒、聚合物微球、柔性体6种耐温抗盐调驱体系,分析了各种调驱体系的特点、作用机理和现场应用情况,提出了今后耐温抗盐调驱体系的研究方向,即研制新型的耐温抗盐聚合物、加强对无机体系的研究和研制有机-无机复合体系。参48     

Na3V2(PO4)3 with specially designed carbon framework as high performance cathode for sodium-ion batteries

The structures of materials have great influence on their properties. For materials with low electron conductivity, fast electron transport pathway can be constructed through carbon structure design. Here we report a simple but effective method to improve the electrochemical performances of Na₃V₂(PO₄)₃. Polyvinyl Pyrrolidone (PVP) can improve the viscosity of the precursor solution, thus forming aggregate structured material. In Na₃V₂(PO₄)₃, primary particles with a diameter of approximately 300?nm are aggregated through a special carbon network to form micro-sized secondary particles. This kind of structure will provide easy access for electron transportation, thereby improving electrochemical performance of the material. As a cathode material for sodium-ion batteries, Na₃V₂(PO₄)₃ delivers excellent rate (86.6 mAh g^?1 at 30?C) and cycling performance (capacity retention of 88.4% after 2000 cycles at 10?C). The material also exhibits a specific capacity of 100.2 mAh g^?1 at 5?C under 55?°C. The above-mentioned performance is far better than the control sample without PVP. The special carbon network provides electron transport channels which improves the electrochemical performance of the material. This method may provide new ideas for the preparation of phosphate materials.     

芜菁多糖除蛋白及抑制RAW264.7巨噬细胞焦亡作用研究

目的 考察芜菁多糖两种方法除蛋白效果,并探讨其对RAW264.7巨噬细胞焦亡的抑制作用。方法 采用AB-8大孔吸附树脂法、Savage法去除蛋白,苯酚-硫酸法测定多糖含量,采用脂多糖(lipopolysaccharide,LPS)及三磷酸腺苷(adenosine triphosphate,ATP)建立细胞焦亡模型,细胞毒性检测试剂盒(cell counting kit-8,CCK8)检测芜菁多糖对RAW264.7细胞增殖率的影响,免疫印迹实验(Western-Blot,WB)检测消皮素D (gasdermin D,GSDMD)相对表达量,酶联免疫吸附测定法检测白细胞介素-18 (interleukin18,IL-18)、IL-1β、肿瘤坏死因子-α (tumor necrosis factor-α,TNF-α)、IL-6水平。结果 AB-8大孔吸附树脂除蛋白,多糖保留率为85.9%,蛋白去除率为91.0%;Savage法多糖保留率为77.6%,蛋白去除率为72.8%,精密度、稳定性、重复性和加样回收率的相对标准偏差(relative standard deviation,RSD)均小于...     

A novel logistic multi-class supervised classification model based on multi-fractal spectrum parameters for hyperspectral data

A novel logistic multi-class supervised classification model based on multi-fractal spectrum parameters is proposed to avoid the error that is caused by the difference between the real data distribution and the hypothetic Gaussian distribution and avoid the computational burden working in the logistic regression classification directly for hyperspectral data. The multi-fractal spectra and parameters are calculated firstly with training samples along the spectral dimension of hyperspectral data. Secondly, the logistic regression model is employed in our work because the logistic regression classification model is a distribution-free nonlinear model which is based on the conditional probability without the Gaussian distribution assumption of the random variables, and the obtained multi-fractal parameters are applied to establish the multi-class logistic regression classification model. Finally, the Newton–Raphson method is applied to estimate the model parameters via the maximum likelihood algorithm. The classification results of the proposed model are compared with the logistic regression classification model based on an adaptive bands selection method by using the Airborne Visible/Infrared Imaging Spectrometer and airborne Push Hyperspectral Imager data. The results illuminate that the proposed approach achieves better accuracy with lower computational cost simultaneously.     

PCR-免疫胶体金试纸条方法检测食品中 肠出血性大肠杆菌O157:H7

目的建立PCR-免疫胶体金试纸条法快速检测食品中肠出血性大肠杆菌O157:H7的分析方法。方法通过设计特异性引物建立肠出血性大肠杆菌O157:H7 PCR检测方法并使用免疫胶体金技术以及双抗体夹心法建立PCR产物快速检测试纸条并设计核酸检测展开液;将1株大肠杆菌O157:H7标准菌株和7株其他常见食源性致病菌作为试验菌株,用试验菌株检测PCR-免疫胶体金试纸条方法的检测特异度,并比较PCR-免疫胶体金试纸条法和PCR-琼脂糖凝胶电泳法的检测敏感度。结果 PCR-免疫胶体金法具有良好的特异度,灵敏度比标准琼脂糖凝胶电泳法高100倍。结论本文建立的肠出血性大肠杆菌O157:H7检测PCR-免疫胶体金试纸条法特异度好,灵敏度高,价格低廉,适用于食品中肠出血性大肠杆菌O157:H7的检测。     

结合Bayer模式与局部相关模型的Demosaicing算法

结合差值模型与小波变换理论,提出高频相似模型,并在理论分析的基础上,给出产生该模型时小波变换应满足的条件;从Bayer模式的内在特征出发,找到其与小波变换过程巧妙结合的方法,进而提出了R,B平面的一种有效重构方法.该方法不用迭代,大大缩短了重建时间,与Gunturk等所提方法的计算代价之比为19∶432.文中还给出了一种完整的demosaicing算法,对比实验表明,所提算法在重建效果和计算代价上都明显占优.     

航空交错 TDI 红外影像复原

针对航空交错延时积分(Time delay and integration, TDI)红外影像奇数行和偶数行之间灰度差异、错动以及影像降晰问题, 提出了一种交错TDI红外影像复原方法. 首先采用对影像灰度差异不敏感的基于相位相关 (Phase-only correlation, POC) 的位移估计方法估计奇数行影像和偶数行影像之间的亚像素精度位移场. 其次以奇数行影像为参考, 根据位移估计结果对偶数行影像做点对点灰度校正, 并对齐奇数行影像和灰度校正后的偶数行影像. 最后采用BTV (Bilateral total variation)正则化超分辨率重建方法反降晰, 得到复原影像. 实验结果表明复原影像中奇偶行的错动得到有效补偿, 地物的边缘和纹理结构更加清晰, 影像质量显著提高.