基于三次Bézier基函数插值的GM(1,1)模型背景值优化研究

本文研究了传统灰色GM(1,1)模型存在模型精度不高的问题.利用带形状参数的三次Bézier基函数,给出插值函数的表达式,并结合复化梯形公式,给定误差限的方法,获得了比传统灰色GM(1,1)模型更高精度的结果.推广了传统灰色GM(1,1)预测模型的结果.     

A unified framework for mapping individual interregional high-order morphological connectivity based on regional cortical features from anatomical MRI

Building individual brain networks form the single volume of anatomical MRI is a challenging task. Furthermore, the high-order connectivity of morphological networks remains unexplored. This paper aimed to investigate the individual high-order morphological connectivity from anatomical MRI. Towards this goal, a unified framework based on six feature distances (euclidean, seuclidean, mahalanobis, cityblock, minkowski, and chebychev) was proposed to derive high-order interregional morphological features. The test-retest datasets and the healthy aging datasets were applied to analyze the reliability and the inter-subject variability of the novel features. In addition, the predictive models based on these novel features were established for age estimation. The proposed six neuroanatomical features exhibited significant high-to-excellent reliability. Certain connections were significantly correlated to biological age based on the six novel metrics (p < .05, FDR corrected). Moreover, the predicted age were significantly correlated to the original age in each regression task (r > 0.5, p < 10⁻⁶). The results suggested that the novel high-order metrics were reliable and could reflect individual differences, which could be beneficial for current methods of individual brain connectomes.     

变频控制直接膨胀式太阳能热泵的数值模拟

文中通过对变频控制直接膨胀式太阳能热泵的数值模拟,指出PV/T- SAHP系统实现变频控制从而解决太阳能热泵集热器面积与压缩机的容量不匹配的关键问题是找到系统集热/蒸发器的MSS线.为变工况下太阳能热泵系统的研究提供参考.     

Ultrasonic-assisted synthesis of Ce doped cubic–hexagonal ZnTiO3 with highly efficient sonocatalytic activity

Ce doped ZnTiO₃ as a novel catalyst with highly efficient and stable sonocatalytic activity was synthesized via an ultrasound-assisted sol–gel method using non-ionic surfactant Pluronic F127 as structure directing agent. Synthesized samples were characterized by using various techniques, such as XRD, TEM, SEM, EDX, ​XRF, BET, DRS, and PL, and their sonocatalytic activity studied toward degradation of p-Nitrophenol as a model organic compound. The synthesized mesoporous Ce/ZnTiO₃ had mixed cubic–hexagonal phase with large surface area (118.2 m² g^–1) and narrow pore size distribution (4.9 nm). The effects of cerium concentration, calcination temperature, and calcination time on the structure and the sonocatalytic activity of Ce/ZnTiO₃ were studied in detail. XRD results were suggested that the relation between the phase structure and the catalytic activity is considerable. Significant decrease in band-gap and PL intensity was observed with increasing the cerium concentration in the ZnTiO₃. It became clear that the Ce/ZnTiO₃ (0.81 mol%) shows high sonocatalytic activity compared with pure ZnTiO₃ and other Ce/ZnTiO₃ samples as well as commercial TiO₂-P25. The possible mechanism for the enhanced sonocatalytic activity of Ce/ZnTiO₃ was discussed in details. The electrical energy consumption was also considered during sonocatalytic experiments.     

Thermal degradation mechanism of flame retarded epoxy resins with a DOPO-substitued organophosphorus oligomer by TG-FTIR and DP-MS

A novel phosphorus-containing oligomeric flame retardant, poly(DOPO substituted hydroxyphenyl methanol pentaerythritol diphosphonate) (PDPDP) was synthesized and applied to flame retarded epoxy resins. The thermal degradation behaviors of flame retarded epoxy composites with PDPDP were investigated by thermogravimetric analysis (TGA), thermogravimetric analysis/infrared spectrometry (TG-FTIR) and direct pyrolysis-mass spectrometry (DP-MS) techniques. The identification of pyrolysis fragment ions provided insight into the flame retardant mechanism. The results showed that the mass loss rate of the EP/PDPDP composites was clearly lower than pure EP when the temperature was higher than 300 °C in air or nitrogen atmosphere. The results also suggested that the main decomposition fragment ions of the EP/PDPDP composite were H₂O, CO₂, CO, benzene, and phenol. The incorporation of PDPDP can reduce the release of combustible gas and induce the formation of char layer, hence the fire potential hazard was reduced.     

基于均匀设计抽样遗传算法求解背包问题

众所周知,遗传算法的运行机理及特点是具有定向制导的随机搜索技术,其定向制导的原则是:导向以高适应度模式为祖先的"家族"方向.以此结论为基础,利用均匀设计抽样的理论和方法,对遗传算法中的交叉操作进行了重新设计,给出了一个新的GA算法,称之为均匀设计抽样遗传算法.最后将均匀设计抽样遗传算法应用于求解背包问题,并与简单遗传算...     

关于CAP-子群的一点注记（英文）

对于有限群G的每一主因子H/K来说,若G的子群L满足LH=LK或者L∩H=L∩K,则称L是G的CAP-子群.本文通过假设G的每个非循环Sylow子群P有一个子群D使得1〈｜D｜〈｜P｜,且P的所有阶为｜D｜和2｜D｜（若P是非交换2-群且｜P∶D｜〉2）的子群H是G的CAP-子群,得到G为p-幂零群的一个结果.     

沉积温度对Cu_2O薄膜生长过程及光电性能的影响(英文)

以硫酸铜为铜源,采用一步化学浴沉积法制备出了晶粒尺寸可调的纳米晶Cu2O薄膜。通过X射线衍射、扫描电镜和紫外可见分光光度法研究了沉积温度对薄膜晶体结构、成核密度、晶粒尺寸、薄膜厚度和光电性能的影响。结果表明,当在60~90℃范围内调节温度时,能够很好地控制晶粒尺寸、薄膜厚度,并将禁带宽度控制在33~51 nm、392~556 nm和2.47~2.61 eV范围内;随着晶粒尺寸的减小,紫外可见光谱的吸收边有明显的蓝移。此外还对薄膜的生长过程,成核密度和颗粒尺寸变化的机理进行了讨论。     

Electrophile-driven copper-catalyzed one-pot synthesis of 3-halogen quinoline derivatives

A convenient and regioselective one-pot synthesis of 3-chloride or 3-bromide quinoline derivatives was achieved through a Grignard addition reaction by alkynyl Grignard regent to o-trifluoroacetyl aniline and a Cu(II)-catalyzed cyclization–halogenation tandem reaction with aqueous HCl or HBr as electrophilic reagent.     

Cu2+对不同相形态中聚3-己基噻吩光学性质的影响

用紫外-可见吸收光谱和荧光光谱方法研究了Cu2+分别与稀溶液、分散液和薄膜三种体系中的聚3-己基噻吩(P3HT)的相互作用. 结果表明, P3HT的相形态对其相互作用有重要影响. 在四氢呋喃的稀溶液中, P3HT与Cu2+的溶剂化程度都很高, 它们之间几乎不存在化学作用; 在分散液中, P3HT形成聚集的颗粒, Cu2+的加入产生较弱的氧化掺杂, Cu2+部分进入到分散颗粒中; 在P3HT的薄膜中, Cu2+使链的共轭长度变短, 引起光吸收蓝移.