Time-Inconsistent Stochastic LQ Problem with Regime Switching

Journal of Systems Science and Complexity - This paper investigates a time-inconsistent stochastic linear-quadratic problem with regime switching that is characterized via a finite-state Markov...     

一种基于数独分组的拉丁超立方试验设计方法

为解决拉丁超立方设计在复杂因子的实验设计空间中存在优化时间长和因子水平组合爆炸的问题。提出一种基于数独分组的拉丁超立方设计方法。该方法对因子通过数独分组降维,在降维后的各个子空间中平移种子设计。将基于数独分组的拉丁超立方设计与另外两种常用的拉丁超立方设计方法在中高维度试验空间中进行对比,结果表明,基于数独分组的拉丁超立方设计有较优的空间填充性和最短的运行时间。     

Mining and Integrating Reliable Decision Rules for Imbalanced Cancer Gene Expression Data Sets

There have been many skewed cancer gene expression datasets in the post-genomic era. Extraction of differential expression genes or construction of decision rules using these skewed datasets by traditional algorithms will seriously underestimate the performance of the minority class, leading to inaccurate diagnosis in clinical trails. This paper presents a skewed gene selection algorithm that introduces a weighted metric into the gene selection procedure. The extracted genes are paired as decision rules to distinguish both classes, with these decision rules then integrated into an ensemble learning framework by majority voting to recognize test examples; thus avoiding tedious data normalization and classifier construction. The mining and integrating of a few reliable decision rules gave higher or at least comparable classification performance than many traditional class imbalance learning algorithms on four benchmark imbalanced cancer gene expression datasets.     

氧化热处理对不锈钢基碳纳米管结构及其电化学检测性能的影响

采用化学气相沉积法,以不锈钢基体中的Fe、Ni等成分为催化剂,直接在其表面生长碳纳米管并进行氧化热处理。采用场发射扫描电镜观察制备的碳纳米管形貌及尺寸,并采用接触角测量方法检测试样亲水性质,结合透射电镜、拉曼光谱和XPS检测分析氧化热处理引起的碳管形貌和特征差异,最后考察尿酸在碳纳米管电极上的电化学响应。结果表明,氧化热处理使碳纳米管平滑的表面变得粗糙,暴露出了更多的边平面结构,并且碳纳米管从疏水变为超亲水状态,使其在电化学反应过程中电极表面能够更好地与溶液中的物质接触,有利于材料电化学性能的提高;以经过氧化热处理的碳纳米管为电极,能够在大量抗坏血酸存在的条件下选择性地测定尿酸。     

Effects of metal binder on the microstructure and mechanical properties of Al2O3-based micro-nanocomposite ceramic tool material

The Al2O3?(W,Ti)C composites with Ni and Mo additions varying from 0vol% to 12vol% were prepared via hot pressing sintering under 30 MPa. The microstructure was investigated via X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy dispersive spectrometry (EDS). Mechanical properties such as flexural strength, fracture toughness, and Vickers hardness were also measured. Results show that the main phases A12O3 and (W,Ti)C were detected by XRD. Compound MoNi also existed in sintered nanocom-posites. The fracture modes of the nanocomposites were both intergranular and transgranular fractures. The plastic deformation of metal particles and crack bridging were the main toughening mechanisms. The maximum flexural strength and fracture toughness were obtained for 9vol% and 12vol% additions of Ni and Mo, respectively. The hardness of the composites reduced gradually with increasing content of metals Ni and Mo.     

成语中的量范畴

成语中的量范畴包括大量、小量、比较量、全（满/足）量、群量、等量、增量、减量、合适量、过量（余量）、未然量、连续量、主观量等;量范畴具有种类多样、集双（多）量于一体、量的搭配反映“主景”与“背景”的关系、选择具体的小量和大量指代抽象的小量和大量、明显与隐晦、本义和引申义中的量不平衡等特点;量范畴具有语义、语用和语法作用;有些成语描写了量范畴的弊端及对量的选择;表达或描写量范畴有数量词、形容词、名词、副词、程度补语、叠音与重叠以及比喻等形式.     

纳通道内λ-DNA过孔信号的小波去噪及统计分析

针对λ噬菌体中的脱氧核糖核酸(λ-DNA)通过纳米通道时的过孔信号噪音大,强度弱且非平稳的缺点,提出了使用具有良好时频域分辨能力的小波分析方法对其进行去噪处理,并对有效去噪后的λ-DNA过孔信号进行了统计分析.首先根据小波去噪原理,选择合适的小波函数,确定最佳的分解层数并选取合适的阈值,对实验采集到的含噪声信号进行去噪处理.根据最终去噪效果可得,以sym7为小波基函数、分解层数5层、使用默认软阈值可以有效降低信号中的噪声,提高信噪比.然后,对具有48 000个碱基对(48 kbp)的λ-DNA通过60 nm氮化硅(SiN)纳米孔的特征信号进行了统计分析,分析结果表明,阻塞电流和过孔时间分别符合双峰高斯分布和偏正态分布,这为后续DNA分子的辨识工作提供了依据.     

胞壁结合型生物破乳菌Alcaligenes sp. S-XJ-1氮源利用特性

以六种氨基酸及硝酸铵为氮源培养胞壁结合型生物破乳剂产生菌Alcaligenes sp.S-XJ-1,进而分析菌体对谷氨酸和硝酸铵的利用过程,并建立菌体的生长及氮源利用模型.结果表明:氮源种类和投量是影响菌体产量和性能的重要因素;菌体对氮源的利用顺序依次为有机氮、氨态氮、硝态氮;谷氨酸为氮源时对生物破乳菌产量的促进效果最佳,相比于硝酸铵为氮源时,菌体最大比增长速率和产率系数更高,用于菌体代谢供能的氮源消耗量更低.     

热塑性聚氨酯/凹凸棒土纳米复合材料力学行为研究

通过溶液共混法制备了热塑性聚氨酯（TPU） /凹凸棒土（AT）纳米复合材料,研究AT的加入对TPU基体滞后、拉伸应力软化行为和松弛效应的影响.研究结果显示：随着AT的加入,纳米复合材料的滞后圈增大,拉伸应力软化效应增强,应力松弛速率和程度降低.TPU/AT体系分子链运动模型表明纳米复合材料力学行为的改变,可能是因为AT和TPU基体间形成了氢键,阻碍了分子链的运动。     

GFRP管高强混凝土空心柱轴压试验研究

为研究GFRP管高强混凝土短柱的轴心受压性能,进行了4根不同截面组合柱的轴心受压试验,主要研究其工作机理和破坏形态.试验结果表明:在荷载作用初期,组合柱GFRP管对混凝土没有约束作用,随着荷载作用增加,GFRP管表面出现白纹和轻微的响声;在极限状态时,GFRP管被拉断,并伴随巨大的响声.GFRP管-高强混凝土-钢管组合柱的承载力比GFRP管-高强混凝土-GFRP管组合柱高37%左右.采用统一理论法建立组合柱的轴压承载力计算公式,理论计算结果与试验结果吻合良好.