稀土应用于电化学储能的研究进展

储能是实现清洁能源替代传统化石能源的关键,其核心是开发高效储能材料,其中稀土材料由于独特的电子结构,在电化学储能各领域显示出了巨大应用的前景.主要综述了稀土在铅酸蓄电池、镍氢电池、固体氧化物燃料电池(SOFC)、锂离子电池、超级电容器和锂硫电池中的研究和应用现状,期望发展系统功能材料合成和组装技术,拓展其在未来储能中的应用.     

Hydrogenation of nanostructured semiconductors for energy conversion and storage

Nanostructured semiconductors have been researched intensively for energy conversion and storage applications in recent decades. Despite of tremendous find- ings and achievements, the performance of the devices resulted from the nanomaterials in terms of energy conversion efficiency and storage capacity needs further improvement to become economically viable for subsequent commercializa- tion. Hydrogenation is a simple, efficient, and cost-effective way for tailoring the electronic and morphological properties of the nanostructured materials. This work reviews a series of hydrogenated nanostructured materials was produced by the hydrogenation of a wide range of nanomaterials. These materials with improved inherent conductivity and changed characteristic lattice structure possess much enhanced per- formance for energy conversion application, e.g., photo- electrocatalytic production of hydrogen, and energy storage applications, e.g., lithium-ion batteries and supercapacitors. The hydrogenation mechanisms as well as resultant properties responsible for the efficiency improvement are explored in details. This work provides guidance for researchers to use the hydrogenation technology to design functional materials.     

High temperature electrochemical discharge performance of LaFeO3 coated with C/Ni as anode material for NiMH batteries

Perovskite LaFeO₃ is considered as a promising new anode material for nickel/metal hydride batteries due to its low cost, environmental friendliness and high temperature resistance. However, the poor conductivity of LaFeO₃ material restricts the discharge ability, which is problematic for its future widespread application. To solve the above issue, in this study, we prepared C/Ni-coated LaFeO₃ composite in view of the excellent electrical conductivity of carbon and nickel metal. Results show that the C/Ni-coated LaFeO₃ composite delivers remarkably increased discharge capacity of ～345 mAh g^?1 at 60 ?°C in contrast to ～267 mAh g^?1 for pure LaFeO₃. Furthermore, the carbon and nickel not only increase the electrical conductivity of the LaFeO₃ but also reduces the agglomeration of the LaFeO₃, therefore, the C/Ni-coated LaFeO₃ composite serves superior long cycle-life, which maintains 60.9% after 100 cycles (52.9% for the LaFeO₃ sample). In overall, the electrochemical behavior of the C/Ni-coated LaFeO₃ composite confirms its high potential as nickel/metal hydride batteries for energy storage applications.     

一种改进的特征面积和特征能量计算方法及其应用

特征面积、特征能量算法是时域分析方法中识别信号局部突变的有效手段，但传统算法在用于含有低频或直流干扰信号的场合时具有局限性。分析了无缝钢管在线漏磁检测原理，对钢管缺陷识别技术中的特征面积、特征能量算法进行了改进，提出了新的算法。结果表明，利用改进后的算法对有缺陷区域的特征面积、特征能量进行计算的结果与无缺陷区域的计算结果差别明显，二者之比有大幅度提高。有外伤与无伤特征面积之比值大于28，特征能量之比值大于900，有内伤与无伤特征面积之比值大于10，特征能量之比值大于90。以此特征面积和特征能量作为特征量识别钢管缺陷及判断内、外伤的类型，效果良好。该方法容易实现，适于生产过程中进行实时监测。     

一种改进的特征面积和特征能量计算方法及其应用

特征面积、特征能量算法是时域分析方法中识别信号局部突变的有效手段 ,但传统算法在用于含有低频或直流干扰信号的场合时具有局限性。分析了无缝钢管在线漏磁检测原理 ,对钢管缺陷识别技术中的特征面积、特征能量算法进行了改进 ,提出了新的算法。结果表明 ,利用改进后的算法对有缺陷区域的特征面积、特征能量进行计算的结果与无缺陷区域的计算结果差别明显 ,二者之比有大幅度提高。有外伤与无伤特征面积之比值大于 2 8,特征能量之比值大于 90 0 ,有内伤与无伤特征面积之比值大于 10 ,特征能量之比值大于 90。以此特征面积和特征能量作为特征量识别钢管缺陷及判断内、外伤的类型 ,效果良好。该方法容易实现 ,适于生产过程中进行实时监测     

Binder-free heterostructure(g-C_3N_4/PPy) based thin film on semi-flexible nickel foam via hybrid spray technique for energy storage application

A semi-flexible binder-free graphitic carbon nitride(g-C₃N₄) intercalated polypyrrole(PPy) nanocomposite thin film was prepared via hybrid electrospray technique. A homogeneous thin film was achieved by the controlled spray process. A deposited thin film illustrated the amorphous nature of composite with high surface purity and good chemical composition. The surface analysis confirmed the smoother surface with well-defined distinct phases of g-C₃N₄ and...     

一种改进的RNS算法的研究及应用

针对异常检测问题,改进了混合神经元免疫系统中实数阴性选择算法(RNS,real-valuednegative selection),使其更好地应用在多种纬度的空间上。实验结果表明,使用改进后的实数阴性选择算法(GRNS,general RNS)的神经元免疫系统仅用很少的自体集,就可以达到较高的检测率和比较低的误警率,在高维度特征量的异常检测中取得了很好的效果。     

Reverse microemulsion synthesis of nanostructured complex oxides for catalytic combustion

Catalysts play an important role in many industrial processes, but their use in high-temperature applications-such as energy generation through natural gas combustion, steam reforming and the partial oxidation of hydrocarbons to produce feedstock chemicals--is problematic. The need for catalytic materials that remain stable and active over long periods at high operation temperatures, often in the presence of deactivating or even poisoning compounds, presents a challenge. For example, catalytic methane combustion, which generates power with reduced greenhouse-gas and nitrogen-oxide emissions, is limited by the availability of catalysts that are sufficiently active at low temperatures for start-up and are then able to sustain activity and mechanical integrity at flame temperatures as high as 1,300 degrees C. Here we use sol-gel processing in reverse microemulsions to produce discrete barium hexa-aluminate nanoparticles that display excellent methane combustion activity, owing to their high surface area, high thermal stability and the ultrahigh dispersion of cerium oxide on the their surfaces. Our synthesis method provides a general route to the production of a wide range of thermally stable nanostructured composite materials with large surface-to-volume ratios and an ultrahigh component dispersion that gives rise to synergistic chemical and electronic effects, thus paving the way to the development of catalysts suitable for high-temperature industrial applications.     

无机介孔材料在第三代电化学生物传感器中的应用研究

无机介孔材料是一种孔直径在2,50nm的多孔材料。这种材料具有结构规则,机械性能高、化学和热能稳定性好等特点。近年来,随着材料合成技术的提高,不断有新型高负载能力和生物相容性好的介孔材料被开发出来。同时,实验表明,无机介孔材料是固载生物大分子的良好载体。利用无机介孔材料固载氧化还原蛋白质并结合其的直接电子转移,为我们提供了一种新的构建第三代生物传感器的方法。基于无机介孔材料的特点及氧化还原蛋白质的直接电子转移,所构建的第三代电化学生物传感器有望具有较传统电化学传感器更好的性能。将介孔材料分为二氧化硅基和非二氧化硅基2大类,描述了无机介孔材料在第三代电化学生物传感器中的应用。     

一种改进型宽带SPDT开关的设计及其应用

描述了单刀双掷PIN管开关的原理，提出了一种改进的3倍频程宽带开关，并给出了设计和测量结果，具有频带宽、隔离度高和插损低的特点，弥补了传统并联二极管带宽窄的缺点，结合其在实际天线阵列中的应用，验证了该开关的实用性，给出了其在天线阵中的测量结果．     

Annealing temperature-dependent electrochemical properties of Aeroxide P25 TiO_2 nanoparticles as anode material for lithium storage

TiO_2 has been widely studied as an important electrode material for electrochemical energy storage.Understanding its relationship between textural properties and electrochemical characteristics is essential to boosting its practical performances. Herein, Aeroxide P25 TiO_2 nanoparticles annealing at different temperatures(400–600 °C) were investigated as an anode material of lithium ion battery. Their evolution in crystal phase and microstructural characteristics were characterized by XRD and BET surface analysis, and their lithium storage properties in half-cells were evaluated by various electrochemical analyses, including cyclic voltammetry, cycling testing, and electrochemical impedance spectroscopy. It was found that the lithium storage properties were critically dependent on the size of TiO_2 anode materials. Pristine P25 initially exhibited the highest initial discharge specific capacity due to its smallest particle size; however, rapid capacity loss occurred during extended cycling. The annealing process was found to effectively enhance the cycling stability of TiO_2 although possessing a large particle size and smaller surface area. Typically, P400 showed the best performances in cycling stability, capacity retention ratio, and rate capability, which is mainly attributed to the synergistic effect of high crystallinity, reasonable particle size, and less internal resistance. This study provides an instance of optimizing the textural properties of metal oxides for advanced LIB anode material applications.     

N-(4-羧基苯基)-苯并异硒唑酮的合成工艺研究

以硒、硼氢化钾、对氨基苯甲酸等为原料,通过还原、缩合等反应合成了N-(4-羧基苯基)-苯并异硒唑酮,实验考查了还原剂、溶剂及反应时间对收率的影响,结果表明:还原剂为硼氢化钾,反应溶剂为乙醚-水,反应时间3h,为较佳反应条件,总收率可达46.6％,目标物的结构经过IR、1 H-NMR及ESI-MS等方法确证.     

Sn/C复合材料的制备及作为锂离子电池负极材料的性能

采用SnCl2.2H2O乙醇溶液浸渍竹炭和NaBH4还原方法制备出一种锂二次电池负极用Sn/C复合材料。考察了复合材料中Sn含量对产物收率、微观结构及电化学性能的影响。结果表明,Sn2+大部分进入到竹炭的孔道中,并被还原为单质Sn;当单质Sn与复合材料质量比为42.5∶100时,复合电极材料具有555.1mAh/g的可逆容量,循环20次后容量保持在423.8 mAh/g,显示出较好的实用性能。     

微胶囊化改性氢氧化镁及其在低密度聚乙烯中的阻燃性能研究

采用一步法合成了三聚氰胺树脂和脲醛树脂。分别对氢氧化镁阻燃剂进行微胶囊化改性,通过对其FTIR、SEM、TEM、TG DSC、XRD,以及添加至高聚物中后进行复合材料常规力学性能测试和极限氧指数（LOI）的测定,研究微胶囊化改性超细氢氧化镁的改性效果。结果表明,三聚氰胺树脂和脲醛树脂被成功包覆在氢氧化镁表面,并且改性后氢氧化镁热稳定性良好,粉体与聚合物基体之间的界面粘结性得到提高,与未改性氢氧化镁相比机械性能有较大提高,其极限氧指数较低密度聚乙烯有很大提升。其中,以反应温度70 ℃、包覆量15%的微胶囊化改性效果最好。     

带相变储能的太阳能热水系统分析

提出相变材料(PCM)+水的太阳能联合储能方案,将其应用于24 h供热水的传统太阳能加电辅热热水系统中,建立PCM+水联合储能的数学模型。将该系统应用于昆明地区的情况进行全年模拟分析,对比有无PCM时储热水箱中水温的变化、热损失及电辅热耗电量。结果表明PCM联合储能的热水系统,储热水箱中水温波动小;即加入PCM联合储能对水箱中水温有"削峰填谷"的作用,热损失和电辅热耗电量均减小,全年节电率达17.7%。分析了相变温度与PCM体积比(PCM体积与水体积之比)对水箱储能性能的影响,给出了水箱储热性能随相变温度和相PCM体积比变化的规律及其选取范围。     

多孔LiFePO_4锂电池正极材料制备及电化学性能研究

聚苯乙烯微球(PST)作模板成功地制备出了三维(3D)多孔LiFePO4锂电池正极材料,并与传统固相法制备的LiFePO4比较,分析形貌、性能差异.结果显示,固相法合成的LiFePO4近似呈球形,颗粒大小不均,平均粒径约80~220nm.而模板法合成产物具有3D多孔结构,孔径较为均匀.BET测试显示,3D多孔LiFePO4比表面积较大,为11.239 8m2/g,单孔体积为0.034cm3/g,而固相法合成产物比表面积为2.003 2m2/g,单孔体积为0.006cm3/g.因此,3D多孔LiFePO4为锂电池中锂离子嵌入和脱出提供便利通道.电化学性能显示,两种方法在3.3~3.5V电压区间有一个较好充电和放电平台,固相法最大充放电比容量为60~70mAh·g-1,而模板法合成的多孔材料其稳定性较好,充放电比容量基本稳定在170mAh·g-1左右.电化学阻抗谱(EIS)分析,多孔的LiFePO4材料其欧姆接触电阻(R1)、电化学反应的电荷转移电阻(R2)和半无限边界条件下的扩散阻抗(W1)较之固相法合成LiFePO4材料均小,3D多孔结构有利于减少因阻抗引起的电池容量的损耗,增强电池的稳定性,提高可逆比容量.     

镍渣基矿井充填用胶凝材料的制备

以提高矿业固体废弃物综合利用水平,降低矿山充填采矿成本为目的,本文开展了利用水淬镍渣制备矿山井下充填用胶凝材料的研究。分别采用机械活化和化学活化的方法,对水淬镍渣进行了提高其胶凝性能的探讨。以井下充填体的强度指标为评价标准,分析了磨矿细度和激发剂对水淬镍渣活性的激发程度和胶凝性能的影响,对水淬镍渣的化学活化机理进行了分析。研究结果表明,以活化处理的水淬镍渣为主要原料(占原料总量的85%)制备的胶结剂,可以作为水泥的替代品用于矿井充填料的生产。     

一种改进的TDOA概率定位算法及应用

在TDOA无源定位方法中,定位精度一直是最根本的问题,一个完整的定位解应包括一个最可能定位点坐标和一定误差条件下的定位边界,且定位性能与系统内监测站的布局有关.作者对一种概率定位算法进行了改进以满足实际工程要求.大量试验与仿真表明,改进后的算法降低了运算复杂度,具有很强的实用性,并已经成功运用于无线电网络监测系统.     

改进蚂蚁算法在组合优化中的应用-置换FlowShop问题求解

置换FlowShop问题是生产调度问题中的一种，具有广泛的工程应用背景．有效的调度能够提高企业的生产效率和设备利用率，增强企业竞争能力．然而多机器的置换FlowShop问题属于NP-hard问题，很难得到问题的最优解．文章简单介绍了蚂蚁算法，并提出退火蚂蚁算法一将max-min ant system与模拟退火算法相结合．通过与max-min ant system运算结果进行比较最后得出结论：退火蚂蚁算法性能得到显著提高．     

Facile synthesis of nanostructured LiFePO4/C cathode material for lithium-ion batteries

Nanostructured LiFePO4/C cathode material was prepared by FePO4·2H2O/C precursor by in situ restriction reaction.The synthesized LiFePO4/C cathode material presents a narrow distribution of nano-sized particles and exhibits an excellent electrochemical property with various rates.The facile synthesis route for the preparation of nano-sized LiFePO4 material has the particular advantage of simple synthesis process and low synthesis cost.