Using Wikipedia knowledge to improve text classification

Text classification has been widely used to assist users with the discovery of useful information from the Internet. However, traditional classification methods are based on the “Bag of Words” (BOW) representation, which only accounts for term frequency in the documents, and ignores important semantic relationships between key terms. To overcome this problem, previous work attempted to enrich text representation by means of manual intervention or automatic document expansion. The achieved improvement is unfortunately very limited, due to the poor coverage capability of the dictionary, and to the ineffectiveness of term expansion. In this paper, we automatically construct a thesaurus of concepts from Wikipedia. We then introduce a unified framework to expand the BOW representation with semantic relations (synonymy, hyponymy, and associative relations), and demonstrate its efficacy in enhancing previous approaches for text classification. Experimental results on several data sets show that the proposed approach, integrated with the thesaurus built from Wikipedia, can achieve significant improvements with respect to the baseline algorithm.

Flexible Solid-State Direct Ethanol Fuel Cell Catalyzed by Nanoporous High-Entropy Al-Pd-Ni-Cu-Mo Anode and Spinel (AlMnCo)3O4 Cathode

As in many other electrochemical energy-converting systems, the flexible direct ethanol fuel cells rely heavily on high-performance catalysts with low noble metal contents and high tolerance to poisoning. In this work, a generic dealloying procedure to synthesize nanoporous multicomponent anodic and cathodic catalysts for the high-performance ethanol fuel cells is reported. On the anode side, the nanoporous AlPdNiCuMo high-entropy alloy exhibits an electrochemically active surface area of 88.53 m² g⁻¹_Pd and a mass activity of 2.67 A mg⁻¹_Pd for the ethanol oxidation reaction. On the cathode side, the dealloyed spinel (AlMnCo)₃O₄ nanosheets with no noble metals demonstrate a comparable catalytic performance as the standard Pt/C for the oxygen reduction reaction, and tolerance to high concentrations of ethanol. Equipped with such anodic and cathodic catalysts, the flexible solid-state ethanol fuel cell is able to deliver an ultra-high energy density of 13.63 mWh cm⁻² with only 3 mL ethanol, which is outstanding compared with other similar solid-state energy devices. Moreover, the solid-state ethanol fuel cell is highly flexible, durable and exhibits an inject-and-run function.     

基于固液两相流模拟的选矿循环水深度澄清装置优化

部分选矿循环水中含一定量的高分散性悬浮颗粒,仅依靠简单浓缩沉降难以澄清,无法达到回用要求。针对这一难题,提出了一种选矿循环水固体悬浮物澄清装置。为优化装置的结构参数与运行参数,建立了选矿循环水深度澄清装置的二维物理模型,基于计算流体力学（CFD）的方法,选用Mixture和RNG k?ε 模型对装置主要的结构参数与运行参数展开了数值模拟研究。研究发现适当降低水力循环区喷嘴长度,增加喉管与喷嘴管径比、颗粒沉降区开口尺寸、装置直径等结构,能够降低颗粒沉降区平均湍动能,由于湍动能为单位质量流体由于紊流脉动所具有的动能,故降低了颗粒沉降区流场的紊流程度,增加了水流的稳定性,提高了装置对悬浮颗粒的去除效果;同时发现降低入口流速、增加悬浮颗粒粒径有助于提高悬浮物的去除率,当进水流速为0.1 m·s?1、经过混凝的悬浮颗粒形成粒径大于100 μm时,装置对选矿循环水中的悬浮颗粒去除效果显著。      

基于Visual LISP的监控面积智能化快速计算

研究了目前智能建筑的监控设备所能监控区域面积的智能化计算问题,提出了监控面积计算方法,增加了可视化的显示功能,其方法对开发具有智能化的智能建筑安防系统有重要借鉴价值.     

Measurement of Absorption and Scattering With an Integrating Sphere Detector: Application to Microalgae

A spectrometer with an integrating sphere (IS) detector was used to measure the absorbance due to scattering and absorption. Analysis of the measurement process showed that two measurements of the absorbance, one with the cuvette placed in the normal spectrometer position, and the second with the cuvette placed next to the entrance aperture of the IS detector, provide enough information to separate the contributions from scattering and molecular absorption. Measurements were carried out with mixtures of microsphere and chromophore solutions. Two cases were examined: microspheres suspended in an aqueous fluorescein solution, and microspheres suspended in an aqueous holmium oxide solution. In both cases, the proposed measurement model gave results which were in good agreement with the expected response. Measurements on microalgae suspensions yielded a molecular absorption contribution and a scattering contribution. The scattering contribution had significant spectral structure which was inversely related to the molecular absorption contribution. The absorption and scattering contributions may provide independent information on the status of chlorophyll molecules and the structure of chloroplasts in microalgae.     

Applications of Self-Collimated Properties of Photonic Crystal in 3D Imaging Lidar System

Photonic crystals(PCs)are increasingly attracting attention due to their ability to control light propagation.In this paper,the dispersion properties of a two-dimensional(2D)square lattice PCs with plane-wave expansion(PWE)method are presented,the equi-frequency contours and the band structure are analyzed,and the alignment transmission characteristics are simulated by using the finite difference time domain(FDTD)method,in addition,for the wavelength of 1.55μm,a kind of application structure with the lattice constant a=405nm and the radius of air holes R=135nm which can restrict the transmission of beams in photonic crystal without defect is proposed and simulated.The structure which can collimate the output beam and compress its divergence angle is easy to design.It has wide application prospects in optical communication and three-dimensional(3D)imaging lidar systems.     

建筑群下复杂断层倾斜煤层充填条带开采技术研究

为防止或尽可能减轻开采对环境和其他资源的不良影响,取得最佳的经济效益和社会效益,以某矿井的3#、4#煤层开采为基础,讨论了条带开采的工作面布置,利用概率积分法对3#、4#煤层不同开采工艺下的地表沉陷做出预测,并确定了采空区充填参数。     

电感耦合等离子体质谱法测定莲藕中的铅、镉、铬、砷和汞

目的 建立电感耦合等离子体质谱法同时测定莲藕中的铅、镉、铬、砷和汞含量的分析方法。方法样品经微波消解后,以209铋、115铟、72锗内标溶液消除非质谱干扰,以氦气为碰撞反应气消除质谱干扰。采用基准物质大米粉GBW(E)100348、菠菜GBW10015和加标回收率验证方法的准确度。对方法的线性范围、检出限、精密度和回收率等进行了考察。结果 铅、镉、铬、砷和汞5种元素的线性范围分别为0～50、0～50、0～50、0～50和0～2μg/L;相兲系数r分别为0.9996、0.9996、0.9991、0.9997和0.9990;平均加标回收率分别为97.3%、97.5%、95.7%、96.0%和97.4%;相对标准偏差分别为0.37%、0.89%、1.04%、1.03%、1.58%;检出限分别为0.001、0.002、0.002、0.001和0.0003mg/kg。结论 该方法操作简便,干扰较小,灵敏度高,同时检出限低、精密度高、准确度好,适用于同时检测莲藕中的铅、镉、铬、砷和汞。     

高电压锂离子电池LiNi0.5Mn1.5O4的合成及性能

以Li2CO3,NiO和电解MnO2为原料,用固相法合成了LiNi0.5M n1.5O4。采用XRD,SEM和恒流充放电测试研究了合成样品的性能。XRD测试表明,在950℃下加热12h,然后600℃下退火48h,所得样品具有立方尖晶石结构。电化学测试表明,充放电曲线只在4.7V附近存在电压平台,但容量及循环性能有待于提高。     

双草酸硼酸锂的制备新方法、表征及性能研究

详细介绍了一种锂离子电池电解质盐双草酸硼酸锂（LiBOB）的新制备方法——乙腈溶剂法. 制备过程采用硼酸、碳酸锂、草酸等作为原料, 首先采用P204萃淋树脂预处理锂源, 后将反应物置于乙腈溶剂中直接反应, 所得产品经过乙二醇二甲醚提纯后即得到产物. 产物通过红外光谱和X射线衍射检测手段定性, 用原子吸收和离子色谱检测手段定量, 证明所制备的LiBOB杂质含量少, 纯度达到99.95%. 并通过热分析证实其热稳定性优于一般商品用LiBOB, 整套实验方法优势明显.