基于分数阶微分的图像增强算法

相比传统的基于整数阶微分的图像增强算子,分数阶微分增强算子能提升图像的高频边缘信息,且非线性保留图像纹理细节和平滑区域的中低频信息。文中根据Riemann-Liouville分数阶微分定义,构造了5×5大小的分数阶微分增强算子模板,同时采用传统的整数阶图像增强算子Sobel算子、Prewitt算子和Laplacian算子,分别对灰度图像和彩色图像进行图像增强处理实验。最后,引入图像熵的计算,对图像增强的结果进行熵值大小的计算与分析。随着分数阶微分阶次的增加,分数阶微分增强算子处理后的图像熵值呈上升趋势,说明图像的纹理细节信息得到了加强。     

Relay Scheme Based on Distributed Luby Transform Codes for InterPlaNetary Internet

Distributed Luby Transform （DLT） codes have been proposed to improve the robustness and system throughputs for multisource single-sink networks by exploiting the benefits of Network Coding （NC） at a single relay. All the proposed schemes such as the DLT and Soliton-Like Rateless Coding （SLRC） have attempted to maintain Robust Soliton Distribution （RSD） or Soliton-Like Distribution （SLD） for the output data at the relay. This rzsult in some source symbols to be discarded, thereby degrading the throughput. In this paper, we have proposed a novel method called the Full DLT （FDLT） coding scheme to be applied in the InterPlaNetary （IPN） Internet scenario comprising two sources and one relay The aim of the proposed scheme is to fully utilise the source symbols so as to reduce the overheads and improve energy efficiencies at the sources while maintaining low overhead at the relay. In addition, almost no buffer is needed in the proposed scheme so the relay can have limited storage space, and the proposed scheme is resilient to the churn rates of the nodes. The simulation results have shown that the proposed scheme outperforms the aforementioned schemes with respect to source overheads and total overhead in addition to preserving the benefits of NC and LT codes.     

石英晶体微天平驱动电路设计

石英晶体微天平能够测量微小质量的变化,其广泛应用在生物医学、蛋白质、气体等的吸附检测。本电路设计以STC15F2K60S2单片机为核心,利用石英晶振片的特性,振荡器的起振、稳定振荡原理,以及自动增益控制等方法,构造稳定的振荡电路,实现对石英晶片频率变化的直接测量,进而推断出相应的质量变化。使用LCD显示模块,实时显示频率、质量等的测量值,并扩展RS232接口,实现与上位机之间的通信。     

麻痹性贝毒产毒藻株的三维荧光光谱识别技术研究

利用三维荧光光谱技术,研究了以微小亚历山大藻 （台湾株）（AMSY）、塔玛亚历山大藻（大亚湾株）（ATDY）、链状裸甲藻（防城港株）（GCFC）、塔玛亚历山大藻（香港株）（ATHK）、链状亚历山大藻（南海株）（ACSY）5株4种产麻痹性贝毒(PSP)微藻以及21株不产PSP藻在不同温度条件下培养微藻的各生长期产毒能力与三维荧光的关系。研究结果表明,在不同温度条件下,产毒藻类单位藻细胞产毒量会发生显著变化,低温可促进麻痹性贝毒的产生。通过Db7小波分解,选取Ca3尺度分量的联合荧光谱作为特征谱并利用Fisher判别发现,产PSP藻与不产PSP藻荧光差异主要集中在λ_ex为400~425和450~545nm;λ_em为715~750 nm的波段,利用判别函数建立判别式,实现了对产麻痹性贝类毒素藻类的识别测定。对产PSP毒素藻类的判别率达到93.7%,不产PSP毒素藻类判别率达到93.3% ,综合判别率为93.5%。该研究可实现对水体中活体产PSP微藻的快速识别,为进一步开发产毒微藻识别仪提供理论基础。     

酰胺接枝ACF的制备及其在处理水体中重金属Cu2+的应用

利用聚丙烯腈基活性碳纤维(PAN-ACF)表面存在的羧基与氯化亚砜SOCl2发生酰氯化反应后与乙二胺110℃加热回流在其表面接枝胺基、酰胺基团对其进行改性,用傅立叶转换红外光谱仪(FTIR)、X射线光电子能谱仪(XPS)对改性前后活性碳纤维的表面结构和元素结合态及含量变化进行了表征,并将改性后的活性碳纤维(NH-ACF)应用于水体中Cu2+离子的去除处理,用电感耦合等离子体原子发射光谱仪(ICP-AES)检测被处理溶液中的Cu2+离子浓度变化,进而得出Cu2+离子在NH-ACF上的最大吸附量qmax.结果表明,NH-ACF比未改性处理的PAN-ACF对Cu2+吸附去除能力具有显著的优势,前者约为后者的1.5倍.     

陈皮中黄酮类化合物的微波辅助提取

黄酮类化合物对人体具有多种生理活性,对黄酮的提取研究具有重要的实用意义。实验通过改装微波炉,采用微波法提取陈皮中的黄酮类化合物,研究了乙醇浓度、微波温度、微波时间、微波反应器的火力点对黄酮提取率的影响。通过正交试验,确定了最佳提取工艺条件。     

Mechanism into selective oxidation of cinnamaldehyde using β-cyclodextrin polymer as phase-transfer catalyst

Selective oxidation of cinnamaldehyde to benzaldehyde in the presence of bicarbonate and hydrogen peroxide and catalyzed by β-cyclodextrin polymer (β-CDP) was investigated. β-CDP was utilized as the phase-transfer catalyst in this study. The immobilized β-cyclodextrin possessing a hydrophobic host cavity was found to be efficient as mass-transfer promoters for the oxidation of cinnamaldehyde. Benzaldehyde could be obtained in 63% yield under optimal reaction conditions. The results indicate the complex formed between cinnamaldehyde and β-CDP via the intermolecular weak interactions, e.g., hydrogen bond was the reason why the conversion and selectivity could be significantly promoted. Finally, the reusability of the catalyst was also evaluated. Its catalytic activity remained unchanged even after recycled for six times, which suggests it is an efficient catalyst for oxidation of cinnamaldehyde.     

La1-xCaxMnO3外延薄膜的制备、结构及磁电阻效应

采用溶胶-凝胶旋涂法在单晶LaAlO3 (100)基片上生长了La1-xCaxMnO3(x=0, 0.05, 0.1, 0.2)外延薄膜. 利用X射线衍射仪(XRD)、 原子力显微镜(AFM)、 聚焦离子束系统(FIB)、 X射线光电子能谱分析仪(XPS)、 振动样品磁强计(VSM)和磁性测量系统(MPMS)对样品的结构、 形貌、 价态、 居里温度和磁电阻效应进行了研究. 结果表明, 薄膜为立方钙钛矿结构, 具有明显的(100)外延生长取向和平整的表面. 在居里温度附近, 样品发生铁磁-顺磁转变. 随着Ca2+掺杂量的增加, 样品的居里温度升高, La0.8Ca0.2MnO3的居里温度为264 K. 随温度的变化, 样品发生了金属-绝缘体转变. 样品还具有较大的磁电阻效应, 在H=2.0 T, T=210 K时, La0.95Ca0.05MnO3的磁电阻达到80.9%.     

First-Principle Calculations for Elastic and Thermodynamic Properties of Diamond

The elastic constants and thermodynamic properties of diamond are investigated by using the CRYSTAL03 program. The lattice parameters, the bulk modulus, the heat capacity, the Grüneisen parameter, and the Debye temperature are obtained. The results are in good agreement with the available experimental and theoretical data. Moreover, the relationship between V/V₀ and pressure, the elastic constants underhigh pressure are successfully obtained. Especially, the elastic constants of diamond under high pressure are firstly obtained theoretically. At the same time, the variations of the thermal expansion α with pressure P and temperature T are obtained systematically in the ranges of 0-870 GPa and 0-1600 K.     

间苯二甲酸连接的氢键导致的二维锌配位聚合物的合成及晶体结构

由于配位聚合物在催化材料,磁性材料和光学材料等领域内具有广泛的 应用价值,近年来人们已经合成了不少多维配位聚合物,并对其进行了结构鉴定和性质研究。配位聚合物一般都是通过体系内的配位键、氢键,和金属－金属间相互作用等作用力形成。在大多数的体系中,一般采用含氮基团,如4,4－联吡啶,2,4,6－三（4－吡啶基）－1,3,5－三嗪,1,4－二咪唑丁胺等作为桥连配体合成具有各种不同拓扑结构的无限伸展体系。同时,利用含氧基团作为桥基合成各类配位聚合物也是一个重要的途径,一般为多酸体系,如1,3,5－三苯甲酸,马来酸等。我们通过分子自组装作用,合成了一例由间苯二甲酸作桥基通过氢键导致的金属锌的二维配位聚合物,通过单晶X－射线衍射,研究了它的结构。