A novel non-enzymatic hydrogen peroxide sensor based on Co:ZnO modified electrodes

There is currently intense interest in the use of nanoparticles for a wide range of biomedical and technological applications. In this paper, the hierarchical Co doped ZnO nanoflowers were synthesized by a facile wet chemical method and explored as biosensing material. The as-modified novel hydrogen peroxide sensor exhibited a wide linear range(0.25–20 mM), highly reproducible response(R.S.D. of 2.7%) and long-term stability. The doping Co~(2+)ions carried out the oxidations rapidly and efficiently for the catalysis of hydrogen peroxide(H_2O_2). A high activity toward H_2O_2 in the presence of ascorbic acid(AA) and NaNO_2, which are only common for natural enzymes, has also been demonstrated. The good analytical performance, low cost and straightforward preparation method makes this doped semiconductor promising for a wide range of potential applications in medicine, biotechnology and environmental chemistry.     

基于分数阶位置状态的量子粒子群算法

由量子力学的概念和粒子群优化算法的结合,量子行为粒子优化算法作为粒子群算法的一个变种,具有更好的全局搜索能力.为了提高量子粒子算法的全局搜索能力,结合分数阶微积分的概念,本文提出了一种新的算法.该算法将分数阶微积分中常用的GL定义引入了量子粒子算法的更新迭代公式中,利用分数阶微积分的长时记忆特性,通过记忆量子粒子在更新迭代过程中的历史位置和历史信息,增强算法的收敛速度和收敛精度.为了全面评估算法的基本性能,本文进行了一些关于基本测试函数的功能测试.通过对于不同阶次的分数阶量子粒子算法的对比实验和与其他粒子群改进算法的对比实验,实验结果表明,该算法具有更高的收敛精度.     

Structure prediction for the down state of a potassium channel voltage sensor

Voltage-gated potassium (Kv) channels, essential for regulating potassium uptake and cell volume in plants and electrical excitability in animals, switch between conducting and non-conducting states as a result of conformational changes in the four voltage-sensing domains (VSDs) that surround the channel pore. This process, known as gating, is initiated by a cluster of positively charged residues on the fourth transmembrane segment (S4) of each VSD, which drives the VSD into a 'down state' at negative voltages and an 'up state' at more positive voltages. The crystal structure of Kv1.2 probably corresponds to the up state, but the local environment of S4 in the down state and its motion in voltage gating remains unresolved. Here we employed several conditional lethal/second-site suppressor yeast screens to determine the transmembrane packing of the VSD in the down state. This screen relies on the ability of KAT1, a eukaryotic Kv channel, to conduct potassium when its VSDs are in the down state, thereby rescuing potassium-transport-deficient yeast. Starting with KAT1 channels bearing conditional lethal mutations, we identified second-site suppressor mutations throughout the VSD that recover yeast growth. We then constructed a down state model of the channel using six pairs of interacting residues as structural constraints and verified this model by engineering suppressor mutations on the basis of spatial considerations. A comparison of this down state model with the up state Kv1.2 structure suggests that the VSDs undergo large rearrangements during gating, whereas the S4 segment remains positioned between the central pore and the remainder of the VSD in both states.     

An Analysis of International Data Encryption Algorithm（IDEA） Security against Differential Cryptanalysis

The security of international date encryption algorithm （IDEA（16））, a mini IDEA cipher, against differential cryptanalysis is investigated. The results show that [DEA（16） is secure against differential cryptanalysis attack after 5 rounds while IDEA（8） needs 7 rounds for the same level of security. The transition matrix for IDEA（16） and its eigenvalue of second largest magnitude are computed. The storage method for the transition matrix has been optimized to speed up file I/O. The emphasis of the work lies in finding out an effective way of computing the eigenvalue of the matrix. To lower time complexity, three mature algorithms in finding eigenvalues are compared from one another and subspace iteration algorithm is employed to compute the eigenvalue of second largest module, with a precision of 0.001.     

文学翻译的“度”的研究

文学翻译因其翻译对象——文学作品的特殊性,译者在翻译时经常会发挥自己的主观能动性去创造性地翻译原作品,造成译作在某种程度上背叛了原作,这种现象有其必然性,但应该有"度"。本文重点研究在翻译过程中,译者受到哪些因素的约束。     

残障学生健康心理之养成

分析了残障学生特殊心理问题的形成及心理健康问题的原因, 并根据其分类的不同分析了肢残生挥之不去的自卑及对人生的茫然与朦胧; 指明了解决残障生心理健康问题的途径和方法。途径是一般性补偿和科学补偿。方法是教育心理学方法和特别研究设置的补偿方法, 还提出了因人施教、递进式教育方法及实施新科技教学方法。     

考虑变厚度的杂交应力元

提出了用于变厚度板平面应力问题分析的杂交元列式,其中以位移场和膜力场为独立未知场量.基于Pian-Sumihara四边形杂交单元的五参数应力场和常规双线性位移场构造一个变厚度平面四边形杂交元.通过若干数值算例验证了新单元的正确性和优越性.     

基于S3C2440和ADS1294的心电信号采集和处理系统

介绍了一套基于S3C2440嵌入式处理器和ADS1294模数转化芯片的心电信号采集、处理系统,S3C2440根据ADS1294的工作时序对其进行控制、采样和输出多导联心电信号.S3C2440采用LC/OS-Ⅱ实时操作系统,在接收采样后的心电信号的同时,进行了FIR和IIR软件滤波.最后给出了经过采样、滤波处理的心电波形图,验证了整套系统的可行性.     

基于BP神经网络模型的滑坡易发性评价方法

滑坡是中国频发的地质灾害,滑坡的易发性评价涉及多种影响因素,如何利用多影响因素进行精确、有效的滑坡易发性评价是滑坡减灾防灾工作的重点和前提。为探讨基于反向传播(back propagation, BP)神经网络模型的不同滑坡易发性评价方法的适用性,以川西蒲江县为研究区,通过实地调查与编录,筛选地质、地貌、环境等12类影响因子,分析各影响因子与滑坡的相关性,确定影响因子的权重大小,构建BP神经网络模型,完成因子权重法和栅格赋值法的滑坡易发性评价图编制和精度评价。结果显示：研究区筛选的12类滑坡影响因子不存在线性相关,坡度、地形湿度指数(topographic wetness index, TWI)和距道路距离对区内滑坡发育影响明显,利用滑坡影响因子构建的BP神经网络模型可对滑坡易发性进行有效的定量评价。综合现场调查与接收者操作特征(receiver operating characteristic, ROC)曲线精度分析,结果表明：基于BP神经网络模型的栅格赋值法和因子权重法曲线下面积(area under curve, AUC)分别为0.86和0.798,栅格赋值法评价精度优于因子权重...     

基于区块链的电子病历共享与可验证方案

为解决传统电子病历存储方案共享难、数据易篡改和隐私泄露问题,为此构建一种基于区块链的电子病历可搜索加密存储、高效共享与可验证方案。通过使用简洁非交互零知识证明(zero-knowledge succinct non-interactive arguments of knowledge, zk-SNARKs)构建用户身份认证系统,提高用户身份的隐私性,匿名性。通过提出基于改进Merkle树的格可搜索加密方案,实现电子病历的可搜索加密与验证方案;并在此基础上通过智能合约构造搜索方案的双重验证。通过将相应的加密数据外包到星际文件系统(interplanetary file system, IPFS)以降低存储成本。通过实验对加密算法性能、智能合约时间和花费开销、链下存储性能进行仿真测试。验证了该系统能够满足电子病历系统应用需求,并提高了数据完整性、搜索效率性和身份保密性。