Co-occurrence of Dominant Direct and Indirect Transitions in Low Temperature Sputtered Indium Tin Oxide Thin Films on Polymers

Indium tin oxide （ITO） layers are prepared on polymethylmethacrylate and polyethylene terephthalate by rf- magnetron sputtering at room temperature. Their 3D-AFM images and visible transmittance spectra are contrastively characterized and studied. An interesting morphological effect of the polymer substrates on their top ITO layers is observed. Dominant direct and indirect transition types deduced from optical spectra are surprisingly found in ITO films on different polymers. Furthermore, qualitative band structures are figured, and some theoretical discussions about the correlation of optical band structure, interface/surface morphology and carrier density are also presented.     

BPR氧化减色法测定过氧化氢亨利常数

利用冷阱收集气-液平衡管出来的气相过氧化氢,以及氯化血红素(Hemin)催化下溴邻苯三酚红(bromopyrogallolred,BPR)被过氧化氢氧化减色的分光光度法检测,测定了温度依赖的过氧化氢亨利常数。在10~35℃的范围内,过氧化氢亨利常数KH(mol·L-1·atm-1)表达为lnKH=a/T-b,其中a=7269±22,b=13·26±0·08,T为温度(K)。过氧化氢溶解焓ΔH为60·43±0·18kJ·K-1·mol-1。     

Improving the precision of fluorescence lifetime measurement using a streak camera

Streak camera has high temporal resolution and high sensitivity, and is a powerful tool in biomedical study to measure fluorescence lifetime and perform fluorescence lifetime imaging. However, nonuniformity of the gain in the streak tube and nonlinearity of the sweeping speed limit the precision of fluorescence lifetime measurement, particularly when fluorescence lifetimes are short. We have constructed a two-photon excitation fluorescence lifetime measurement system that is based on a synchroscan streak camera and have developed accordingly a method to correct the effect of gain nonuniformity and nonlinearity of sweeping speed on the measurement precision. A continuous-wave laser of high stability is used to calibrate the gain of the streak camera, and a Fabry-Perot etalon is used to calibrate the nonlinearity of the sweeping speed. Fitting algorithms are used to correct the gain of the streak camera and nonlinearity of the sweeping speed respectively, which significantly improves the measurement precision of the system, as characterized through the fluorescence lifetime of the short-lived fluorescence dye, Rose Bengal. Experimental results show that the measurement fluctuation of the lifetime has been improved from more than 10% to 2% after correcting the effects of gain nonuniformity and sweeping speed nonlinearity.     

Uptake of transferrin-conjugated quantum dots in single living cells

We study the uptake and distribution of transferrin （Tf）-conjugated CdSe/CdS/ZnS quantum dots （QDs） in single living HeLa cells with both fluorescence confocal microscopy and three-dimensional （3D） reconstruction technique. By increasing the co-incubation time or the dosage of QDs-Tf, we find that the uptake of QDs-Tf bioconjugates in the cells increases correspondingly, but with different uptake rates. Additionally, the distribution of QDs-Tf, in single live HeLa cells is time dependent. To our knowledge, this is the first study on quantitatively analyzing the uptake and distribution of bioconjugated QDs in single living cells. Such QDs nanoplatform can be further modified for developing biomedical evaluation tool in cancer diagnosis and targeted drug delivery.     

L~2(R~n)空间上的不确定原理

该文主要研究L~2(R~n)空间上的不确定原理,将时频分析中信号的时间和Fourier的频率定义推广到了L~2(R~n)空间上.得到了L~2(R~n)空间上一个更强形式的不确定原理.并得到了不确定原理等式成立的条件.     

The Initial Reactions of H3PO4 and NaH2PO4Supported on Silica: A Joint Experimental and Theoretical Study

利用XRD、TG、DRIFTS、31P MAS NMR和密度泛函理论研究了浸渍法制备的硅胶负载型磷酸和磷酸二氢钠催化剂,阐明了催化剂制备过程中生成的初始缩合产物和其反应机理. 光谱试验结果显示,在二氧化硅负载的磷酸上,除了聚磷酸外,还有硅磷酸盐的存在;在二氧化硅负载的磷酸二氢钠上,仅发现聚磷酸钠存在. 密度泛函模拟结果也证明,磷酸与二氧化硅表面硅羟基之间的反应在缩合反应的初始阶段比其自身的二聚反应更为有利. 但是在硅胶负载的磷酸二氢钠上,磷酸二氢钠的二聚和三聚是缩合反应初始阶段的主要反应.     

新型衍射光学成像光谱仪的设计和分析

为了克服在传统衍射光学成像光谱仪中,衍射透镜的焦距随波长变化引起系统放大率随波长变化,从而导致光谱图像的像元配准误差,得到并不精确的相对光谱信号强度,提出了将衍射透镜与消色差透镜系统相结合的新型折/衍混合、二组元复合远心成像光学系统的技术方案,具体分析推导了该系统的成像理论.在此理论指导下,利用光学设计软件Zemax设计了一套可见近红外成像光谱仪光学系统.结果表明,不但系统的放大率不随波长变化,而且进一步降低了衍射透镜的加工难度,改进了衍射光学成像光谱仪的光学性能,为新型衍射光学成像光谱仪的研制提供了重要的理论依据和设计指导.     

阿普唑仑的波谱学数据和结构确证

阿普唑仑是一种临床上广泛应用的具有抗抑郁作用的药物. 本文对阿普唑仑进行了¹H、¹³C NMR检测,通过DEPT和¹H-¹H COSY、¹³C-¹H HSQC、¹³C-¹H HMBC等2D NMR技术对该化合物的¹H、¹³C NMR谱的信号进行了全归属,通过量子化学计算和NMR数据证实了化合物中亚甲基上2个氢的磁不等价性. 讨论了红外吸收光谱的特征峰,并对阿普唑仑的TOF MS的裂解途径进行了分析.      

Annealing effects on the microwave permittivity and permeability properties of Fe79Si16B5 microwires and their micowave absorption performances

This paper reports that amorphous magnetic microwires(Fe79Si16B5) have been fabricated by a melt-extraction technique and have been annealed at 600°C and 750°C respectively.Differential scanning calorimeter measurements show that nanocrystalline magnetic phase(α-Fe) has been formed in the amorphous matrix when it was annealed at 600°C.Hard magnetic phase(Fe2B) was formed in the microwires annealed at 750°C,which increases the magnetic coercivity.Microwave permittivity and permeability are found to be dependent on the microstructures.The permittivity fitting results show that multi Lorentzian dispersion processes exist.For microwires annealed at 750°C,their resonance peaks due to the domain wall movements and natural resonance are found higher than those of microwires annealed at 600°C.The microwave absorption performance of microwires annealed at 600°C is found better than microwires annealed at 750°C.     

三个矩阵秩不等式的多种证明

针对线性代数课程教学中三个矩阵秩的不等式的证明展开研究,对每一个不等式,分别给出相应的证明。