NHn,NHm^＋,NHn^—（n—1,2,3;m=1,2,3,4）体系Gaussian—n和CBS—n方法物理化学性质的理论研究（三）NH3,NH3^＋,NH3^—,NH4^＋体系

利用多种方法研究NH3,NH3^＋,NH3^－,NH4^＋体系的物理化学性质：离解能,电子亲合势,离化能,质子亲合势,原子化能。这些方法有Gaussian-n:G1,G2,G2(MP2)以及CBS－n,CBS-4,CBS-Q,CBS-APNO。对所得结果及其误差进行比较和分析。     

Influence of acid leaching and calcination on iron removal of coal kaolin

Calcination and acid leaching of coal kaolin were studied to determine an effective and economical preparation method of calcined kaolin. Thermogravimetric-differential thermal analysis (TG-DTA) and X-ray diffraction (XRD) demonstrated that 900℃ was the suitable temperature for the calcination. Leaching tests showed that hydrochloric acid was more effective for iron dissolution from raw coal kaolin (RCK), whereas oxalic acid was more effective on iron dissolution from calcined coal kaolin (CCK). The iron dissolution from CCK was 28.78wt%, which is far less effective than the 54.86wt% of RCK under their respective optimal conditions. Through analysis by using M?ssbauer spectroscopy, it is detected that nearly all of the structural ferrous ions in RCK were removed by hydrochloric acid. However, iron sites in CCK changed slightly by oxalic acid leaching because nearly all ferrous ions were transformed into ferric species after firing at 900℃. It can be concluded that it is difficult to remove the structural ferric ions and ferric oxides evolved from the structural ferrous ions. Thus, iron removal by acids should be conducted prior to calcination.     

Reconstruction algorithm of computerized ionospheric tomography

Applying the technique of computer tomography to ionosphere detection, Computerized Ionospheric Tomography (CIT) can produce the large scale distribution of electron density in a two dimentional longitudinal section of ionosphere. According to the actual detecting condition of sparse receiver and limited projecting angle, polynomial interpolation method and projecting angle expansion method are proposed. A new energy function is formulated according to the constraint of least neighbourhood error. Simulated annealing is incorporated in the iteration of ART to get the global minimum of energy function. Sun Xiaon; born in May 1968, Ph. D. Current research interest is in computer graphics & Image processing Supported by the National Natural Science Foundation of China     

X、Ku波段宽带低噪声放大器的设计

文章利用有损匹配的方法设计了一种覆盖X、Ku波段的宽带低噪声放大器,其工作频率为8～18 GHz,带内功率增益大于32 dB,增益平坦度小于3 dB,输入输出端口的回波损耗S11和S22均优于-7 dB,噪声系数小于2.8 dB,最大输出功率为16 dBm,且具有工作频带宽、输入输出匹配结构简单的特点.     

近红外光谱法定量分析亚麻油中的主要组分

用厚度为 1cm的玻璃比色皿作为吸收池 ,测定了亚麻油的近红外光谱 ,利用 70 0 0～ 6 0 0 0cm-1范围内的透波率 ,建立了主成分回归分析模型和BP人工神经网络模型 ,用二模型预测了亚麻油中油酸、亚油酸和亚麻酸的含量 ,预测结果的平均相对误差均在 2 %以内 ,并BP人工神经网络模型预测的效果较好。该法可用于亚麻油中主要组分的实时成分分析。     

计算重构光谱分析仪研究进展

光谱测量广泛应用于科学研究及工业生产中,而传统光谱仪因体积庞大难以满足众多应用需求.近年来,快速发展的计算重构光谱分析仪因其具有紧凑小巧、高分辨率和大测量带宽等优势而成为研究热点.光波经过计算重构光谱分析仪后所产生的光斑图案与波长存在一一对应关系,因此采取合适的解调算法可以从生成的光斑图案中重构入射光谱信息.目前计算重...     

牡丹种间花粉粒形态差异性比较

利用扫描电子显微镜对三种牡丹不同品种的花粉形态进行了观察研究,报道了花粉形态特征和种闻差异,探讨了花粉形态特征在种间演化的分类学意义。结果表明,牡丹属牡丹组成熟花粉粒形态大小和外壁纹饰存在着种间差异。     

含有喹啉和香豆素的蓝色发光材料的合成及性能

合成了一种含有喹啉和香豆素基团且发射蓝光的发光材料(QCC),通过紫外-可见吸收光谱和荧光发射光谱对QCC的光物理性质进行了测试.结果 表明QCC的最大吸收峰为330 nm,且在360～540 nm内具有强的荧光发射带.随着溶剂极性的增加,QCC的荧光发射峰出现明显的红移.通过荧光猝灭技术分别观察了QCC与电子给体(D...     

利用扫描电镜分析砍创性骨外伤的研究

在大型显微镜下,对锐器（单刃刀）和钝器（短柄斧）形成的骨外伤的微观形态进行了分析研究．结果表明：通过特征识别骨外伤的砍切痕迹,往往误差较大,某些肉眼看不见的三维特征通过微观分析可以清晰地识别．着重强调扫描电镜（SEM）在骨外伤鉴定中,具有重要的使用价值．     

离子源辅助法制备T iN及等离子体特性研究

采用TCP等离子体辅助电子束蒸发沉积技术,在室温条件下的玻璃基片上制备了纳米结构的氮化钛薄膜.运用X衍射技术对该薄膜进行表征.利用朗缪尔静电双探针诊断了蒸发镀膜装置反应室内等离子体密度及分析其分布规律,并分析了气压和功率对等离子体分布的影响.结果表明:离子源源口等离子体密度较大且分布不均匀;反应室内等离子体迅速扩散,密度变小且分布趋于均匀.