二(2-氨基乙基)-(3-氨基丙基)胺的合成新方法

以二(氰基甲基)胺及丙烯腈为原料，通过亲核加成、氢化反应合成了不等臂有机多胺化合物二(2-氨基乙基)-(3-氨基丙基)胺，标题化合物及其中间产物经多种谱学手段表征确证。在优化条件下，产物的总收率为67％，含量99.5％(HPLC)。     

基于多尺度图谱和局部谱的目标提取算法

针对多尺度图谱算法不能有效提取含有较多纹理或包含差异较大区域的目标物体, 提出了一种结合图像平滑、多尺度图谱和局部谱的目标提取方法。首先对图像进行l0梯度最小化平滑处理, 锐化边缘的同时消除图像的部分纹理信息; 其次通过多尺度图谱方法对图像进行分割, 该算法结合了归一化割算法的高精确度和多尺度算法的高效率性; 最后结合局部谱理论, 将人工选取的种子区域作为约束条件, 进行有偏割向量估计, 通过最大类间方差法将该向量分割成目标和背景。实验表明, 该方法弥补了多尺度图谱算法的不足, 并能产生很好的目标提取效果。     

基于稀疏表示的信号DOA估计

将信号DOA的估计问题转换为一个联合稀疏表示的求解问题.通过对接收数据矩阵的奇异值分解实现各时间和频率快拍数据的联合;然后通过求解一个平滑l0范数稀疏约束的联合优化问题实现信号源DOA的估计.基于稀疏表示的信号DOA估计方法不仅能够有效地减少数据量,而且具有以下优点:更好的抗噪声性能、更高的计算效率、适用于相关和非相关信号.通过与其他DOA估计方法的比较,表明了该方法的有效性和优越性.     

α-Tocopherol alteration of soybean antiherbivory toTrichoplusia ni larvae

The antioxidant vitamin E, <img src="/content/k1865k06h886025l/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-tocopherol, was tested as a candidate elicitor of alterable antiherbivory in soybean plants against cabbage looper larvae. Although a nonspecific antioxidant, vitamin E proved elicitory to the involved sulfhydryl-dependent receptor-energy transducer protein in soybean plasma membrane. Effects of <img src="/content/k1865k06h886025l/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-tocopherol were dependent on dosage, time, and space in the plant. The observed elicited effects were all decreases in herbivory. The best negative phytochemical correlate of looper feeding was the percentage of increased total HPLC peak area of extractables from elicited as compared to nonelicited leaves. Some specific compounds, e.g., glyceollins, were quantitatively major components of the total profile of secondary metabolites.     

基于朴素基因表达式编程挖掘紧致函数

基因表达式编程(GEP)是一种基因型和表现型相分离的进化新模型,为了挖掘紧致的函数关系,分析了进化系统各因素对挖掘紧致函数的影响,提出了带紧致压力的适应度函数来进化函数紧致解。实验表明,带有紧致压力的适应度函数能自动进化计算机程序,适合挖掘的紧致关系,在挖掘紧致函数中,朴素基因表达式编程(NGEP)比GEP提高效率21.7%,与不带压力的系统相比,GEP的平均压缩了31.2%,NGEP系统平均压缩了42.5%;NGEP较GEP更容易发现紧致解,且函数表达形式更容易理解,丰富了NGEP理论.     

Catalytic Combustion of Model Carbon Particles (CPs) over Pt/β-SiC Catalyst

Platinum catalyst supported on a medium surface area <i><img src="/content/l180w9r66167580u/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i>-SiC was successfully used for the catalytic combustion of model carbon particles and compared to a catalyst supported on a low surface area <i><img src="/content/l180w9r66167580u/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"></i>-SiC. The <i><img src="/content/l180w9r66167580u/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i>-SiC-based catalyst showed no deactivation as a function of cycling tests while a strong deactivation was observed on the <i><img src="/content/l180w9r66167580u/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"></i>-SiC-based catalyst. This deactivation was attributed to the progressive encapsulation of the platinum particles by a layer of silica which built up during the combustion cycle. These results render possible the use of Pt/<i><img src="/content/l180w9r66167580u/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i>-SiC catalyst as a diesel carbon particle catalytic filter with continuous regeneration.     

辣椒红色素的提取工艺及稳定性研究

红辣椒中含有纯天然辣椒红色素，研究了辣椒红色素的几种提取方法。用有机溶剂从辣椒中提取红色素，同时对不同温度、不同时间下的色素提取率进行测试，以确定最佳提取条件；研究发现，乙酸乙酯法可以有效地去除辣椒中的辣味，使产品应用于更广泛的领域。本文还研究了辣椒红色素对pH值、光照、温度、金属离子的稳定性。     

基于加权平滑l_0范数的单快拍波达方向估计

针对现有基于压缩感知的DOA估计算法估计精度不高的问题,提出一种基于加权平滑l0范数的单快拍DOA估计算法。所提算法采用一种新的加权方式,在构造一个恰当的平滑连续函数后,根据接收数据的初始解确定一个合适的递减的{σ}序列[σ_1,σ_2,?,σ_J],并对每一个σ值,用最速下降法来求解l0范数的逼近函数H_σ(S)的最小值;然后将该σ值作为下一次迭代的初始值,并在每次迭代开始时更新权值,通过多次的迭代获得逼近函数的最小解,即逼近的最小l0范数。通过仿真实验表明所提算法可对DOA进行有效估计,且容易实现、精度较高,与未加权的改进平滑l_0范数DOA估计方法相比具有更好的估计性能。     

双三相永磁同步电机模型预测电流控制研究

六相逆变器为双三相永磁同步电机提供了丰富的电压矢量资源,能够使预测电流控制变得更加精准,但更多的电压矢量会带来算法计算量过大的问题,同时双三相电机的谐波电流会使电机的损耗增加,需要对其进行抑制。提出了一种改进的模型预测电流控制方法。利用最外围大矢量与次外围中矢量在z1z2子平面方向相反的特性,在一个控制周期内将两个矢量按照相应比例结合并作用于电机,可实现抑制谐波电流的目的。根据定子磁链所在扇区的位置确定出更小范围内的8个预测电压矢量,从而减少了系统运算量。同时以d,q轴电流误差项作为价值函数,消除z1z2子平面的电流误差项,如此可避免权重系数的整定。通过实验对所研究方法进行了验证,结果表明所提MPCC方法可以有效地降低谐波电流,并且具有良好的控制性能。     

The influence of platinum on the maintenance of α-Al2O3 as a protective scale

The influence of externally located platinum on the isothermal stability of <img src="/content/u73l247g42153330/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-Al<sub>2</sub>O<sub>3</sub> scales formed at high temperatures has been examined. It has been observed that a nickel-base alloy forms an external scale of <img src="/content/u73l247g42153330/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-Al<sub>2</sub>O<sub>3</sub> during oxidation at 1200°C, but this scale breaks down isothermally, enabling a faster-growing Cr<sub>2</sub>O<sub>3</sub>-rich scale to develop. However, in the presence of platinum metal alongside the specimen in the furnace hot zone, the breakdown of the <img src="/content/u73l247g42153330/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-Al<sub>2</sub>O<sub>3</sub> scale is postponed for a substantial period of time. It appears that platinum, as the volatile species PtO<sub>2</sub>, is incorporated into the growing <img src="/content/u73l247g42153330/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-Al<sub>2</sub>O<sub>3</sub> scale where it either influences the stress relief mechanism at temperature or reduces oxidation growth stress generation and thus significantly enhances the isothermal stability of the scale.