新光谱变换结合神经网络提取山区地形遥感水体信息

通过对比分析MNDWI结合阈值法和波段谱间关系结合阈值法这两种常见的水体信息法,针对其识别山体阴影和水体的准确率的不高的缺点,提出了一种新的光谱变换结合神经网络分类法。实验结果表明,新光谱变换结合BP神经网络的遥感分类方法基本上消除了山体阴影对水体提取的干扰,提取水体信息的效果比前两种方法要好。     

负载苯基荧光酮纤维富集-GFAAS法测定痕量锗

苯基荧光酮;负载纤维;富集;石墨炉原子吸收;锗     

季铵化聚4-乙烯吡啶衍生物与葫芦脲[6]的超分子自组装及性质研究

通过葫芦[6]脲(CB[6])与季铵化聚4-乙烯吡啶衍生物2在水溶液中于室温下进行超分子组装, 得到一种新型的超分子聚合物3, 并通过¹H NMR, IR, 元素分析, X射线粉末衍射分析(XRD)对其结构进行了表征, 证实CB[6]位于2的侧基脂肪链上, 通过非共价键与2结合; 通过热重分析(TGA)、紫外-可见吸收(UV-vis)对其性质进行了研究, 证实了超分子聚合物3比相应的聚合物2有更高的热稳定性, 以及更强的UV-vis吸收.     

图的无符号拉普拉斯和距离无符号拉普拉斯特征值

Let G be a simple graph. We first show that ■, where δiand di denote the i-th signless Laplacian eigenvalue and the i-th degree of vertex in G, respectively.Suppose G is a simple and connected graph, then some inequalities on the distance signless Laplacian eigenvalues are obtained by deleting some vertices and some edges from G. In addition, for the distance signless Laplacian spectral radius ρQ(G), we determine the extremal graphs with the minimum ρQ(G) among the trees with given diameter, the unicyclic and bicyclic graphs with given girth, respectively.     

用VITA法检测壁湍流喷射事件的归组问题

用子波分析和能量最大准则解决了ＶＩＴＡ法检测壁湍流猝发中的喷射事件的归组问题     

高效液相色谱法测定保健食品中七烯甲萘醌

建立高效液相色谱法测定保健食品中七烯甲萘醌(MK-7)。含油脂类食品先经脂肪酶酶解,再经异丙醇提取,不含油食品直接使用异丙醇超声提取,采用高效液相紫外检测器进行检测。用Intersil ODS–3 C_(18)型色谱柱(4.6 mm×150 mm,5μm),以甲醇–异丙醇(体积比为75∶25)为流动相,流量为1.0 mL/min,检测波长为270 nm,柱温为40℃,进样体积为20μL。MK-7的质量浓度在0.4-20 mg/L的范围内与色谱峰面积具有良好的线性关系,相关系数为0.9998,方法检出限为0.06 mg/L,定量限为0.2 mg/L。含油脂类食品与不含油脂类食品中MK-7平均加标回收率分别为96.2%、103.2%,测定结果的相对标准偏差分别为0.9%、1.0%(n=9)。室温下,MK-7样品溶液在24 h内稳定。该方法操作简单,可用于保健食品中MK-7的含量测定。     

一种变象管分幅/扫描的高时间分辨光谱测量方法

本文详细介绍了西安光机所正在研制中的一种变象管瞬时光谱测量系统,它由WDG30型光栅光谱头与JTG 305型变象管分幅/扫描摄影机组成。文中给出了系统的总体设计考虑、变象管及其控制和主要性能参数。     

压力下CeSb晶体的导电特性研究

在4.2—273K 温区内,0—14 Kbar 压强下,测量了 CeSb 单晶的电阻率.计及 P-f 互作用随温度的变化,我们在理论上计算了与压强有关的 CeSb 磁性电阻率,并将计算结果与实验值比较.     

A Novel Synthesis of Alkaline Earth Silicate Phosphor Sr3MgSi2O8： Eu^2＋, Dy^3＋

A novel method for synthesizing long afterglow silicate phosphor Sr3MgSi2O8：Eu^2＋,Dy^3＋using TEOS and inorganic powders as reactants was reported. Acetic acid as a catalyzer controlled the hydrolysis of TEOS by adjusting pH value of the system. The morphologies of precursor were characterized by transmission electron microscope （TEM）. The structure and optical properties of the phosphor powders were systematically investigated by means of X-ray diffraction and spectrofluorometry. TEM images have reflected the core-shell structure and quasi-spherical morphology of the precursor particles. It was found that the single-phase Sr3MgSi2O8 crystalline structures were obtained at 1050 and 1250 ℃ for the samples prepared with the nano-coating method and the solid state reaction, respectively. The emission intensities of the phosphors prepared by the present method were higher than those by the conventional process. Also, the afterglow characteristic was better than that prepared by solid-state reaction in the comparable condition.     

絮凝剂产生菌(DSF-1)絮凝活性研究(Ⅰ)

采用稀释划线法从土壤中分离得到一株絮凝剂产生菌DSF-1。通过高岭土悬浮液对该絮凝剂的絮凝活性做了初步研究,结果表明DSF-1产絮凝剂具有产生速度快、絮凝活性高、耐热性能良好的优点。