钡-偶氮胂Ⅲ-锌(钴)-邻菲口罗啉多元配合物显色反应的研究

在近中性环境中，研究了钡与偶氮胂Ⅲ、锌（钴）、邻菲口罗啉形成多元配合物的条件及其配合物组成。显色体系的摩尔吸光系数由二元配合物的２．１×１０４Ｌ·ｍｏｌ－１·ｃｍ－１提高到７．４×１０４Ｌ·ｍｏｌ－１·ｃｍ－１。用此方法，经过简单的分离后，可作硅钡合金中钡的光度法测定。     

铜与2-羟基-3-羧基-5-磺酸基苯重氮氨基偶氮苯反应的分光光度法研究及应用

研究了铜与２－羟基－３－羧基－５－磺酸基苯重氮氨基偶氮苯（ＨＣＳＤＡＡ）的显色反应。在Ｔｒｉ－ｔｏｎＮ－１０１存在下和ｐＨ１０．４～１１．５的缓冲介质中，Ｃｕ２＋与ＨＣＳＤＡＡ形成１∶２的红色配合物，其最大吸收波长是５３０ｎｍ，对比度为１０２ｎｍ，表观摩尔吸光系数为１．３１×１０５Ｌ·ｍｏｌ－１·ｃｍ－１。铜在０～０．２４μｇ／ｍＬ范围内服从比尔定律。用于铅锌矿和花生中微量铜的测定，相对误差不大于３．７％，相对标准偏差不大于１．６％（ｎ＝６）。     

钡-偶氮胂Ⅲ-锌(钴)-邻菲啰啉多元配合物显色反应的研究

在近中性环境中,研究了钡与偶氮胂Ш、锌(钴)、邻菲啰啉形成多元配合物的条件及其配合物组成.显色体系的摩尔吸光系数由二元配合物的2.1×104L·mol-1·cm-1提高到7.4×104L·mol-1·cm-1.用此方法,经过简单的分离后,可作硅钡合金中钡的光度法测定.     

新试剂1-(2-羟基苯基)-3-[4-(苯基偶氮)苯基]-三氮烯的合成及与溴化十六烷基三甲铵的显色反应

合成了新试剂１－（２－羟基苯基）－３－［４－（苯基偶氮）苯基］－三氮烯（ＨＰＡＰＴ）,在氢氧化钠碱性介质中,该试剂与溴化十六烷基三甲铵（ＣＴＭＡＢ）形成１∶３的紫红色离子缔合物。λｍａｘ位于５６５ｎｍ,表观摩尔吸光系数为１．５９×１０４Ｌ·ｍｏｌ－１·ｃｍ－１,ＣＴＭＡＢ含量在３—２９．１６ｍｇ·Ｌ－１范围内符合比耳定律。测定了显色体系ＣＴＭＡＢ的临界胶束浓度是１．５０×１０－４ｍｏｌ·Ｌ－１。     

5-(偶氮苯)-8-(4-硝基-1-重氮苯)-氨基喹啉与铜显色反应研究应用

研究了新试剂5－（偶氮苯）－8－（4－硝基－1－重氮苯）－氨基喹啉（PANPAQ）与铜的显色反应，在弱碱性介质中，吐温－80存在下，PANPAQ与Cu（Ⅱ）反应生成2：1紫色络合物，λmax＝615nm，ε＝5.19×10^4L·mol^-1·cm^-1，铜含量在0－15μg/25mL内符合比耳定律，方法用于生物样品中铜的测定，结果满意。     

2-羟基-5-磺酸基苯基重氮氨基偶氮苯与铊(Ⅲ)显色反应的分光光度法研究

研究了 2 羟基 5 磺酸基苯基重氮氨基偶氮苯 (HSDAA)与铊 (Ⅲ )的显色反应 ,在TritonX 10 0存在下和 0 72～ 0 99mol·L-1 氨水介质中 ,铊 (Ⅲ )与HSDAA有高灵敏的显色反应 ,生成 1∶2红色配合物 ,最大吸收波长在 516nm处 ,铊量在 0～ 0 8mg·L-1 范围内符合比尔定律 ,表观摩尔吸光系数为 1 0 4× 10 5L·mol-1 ·cm-1 。在体系中加入酒石酸钠和氰化钠 ,可大大提高试剂的选择性 ,已用于合成水样中痕量铊的直接测定 ,结果令人满意     

Al(Ⅲ)-铝试剂-聚乙烯醇-乙二胺显色体系的研究

研究了在聚乙烯醇 ( PVA)存在下 ,Al( )与铝试剂及乙二胺的显色反应。实验表明 ,在 p H4 .0— 4 .5范围内 ,加入适量的乙二胺 ,对 Al( )和铝试剂的显色反应有明显的增敏作用。最大吸收波长为 5 35 nm,表观摩尔吸光系数为 1.1× 10 4 L· mol-1·cm-1,铝含量在 0 .5— 4 0 μg/ 2 5 m L范围内服从比耳定律 ,用于测定合成水样中的铝 ,结果令人满意。     

溴化5-[4-(4-吡啶丁氧基)苯基]-10,15,20-三苯基卟啉对铜离子显色反应的研究

本文研究了溴化５－［４－（４－吡啶丁氧基）苯基］－１０,１５,２０－三苯基卟啉与Ｃｕ２＋的显色反应条件,络合物最大吸收波长为４１４ｎｍ,试剂（Ｈ４Ｐ２＋）最大吸收波长为４４６ｎｍ。对比度为３２ｎｍ,试剂与铜络合比为１∶１,表观摩尔吸光系数为２．５×１０５Ｌ·ｍｏｌ－１·ｃｍ－１,铜含量在０．２—１．０μｇ／１０ｍＬ内符合比耳定律,可用于痕量铜的测定。     

新显色剂4,4′-二(2,6-二溴-4-硝基苯基重氮氨基)联苯与汞显色反应的研究

本文研究了新显色剂４，４′－二（２，６－二溴－４－硝基苯基重氮氨基）联苯与Ｈｇ（Ⅱ）的显色反应，在表面活性剂ＴｒｉｔｏｎＸ－１００的存在下，于ｐＨ８．８的Ｎａ２Ｂ４Ｏ７－ＨＣｌ缓冲溶液中，试剂与Ｈｇ（Ⅱ）形成２∶２橙红色配合物，其最大吸收峰位于４９０ｎｍ，表观摩尔吸光系数为７．６２×１０４Ｌ·ｍｏｌ－１·ｃｍ－１。Ｈｇ（Ⅱ）量在０－１２μｇ／２５ｍＬ范围内符合比耳定律。方法用于废水中微量Ｈｇ（Ⅱ）的测定，结果满意。     

新显色剂8-喹啉偶氮槲皮素的合成及其与Fe(Ⅲ)显色反应的研究

本文研究了新显色试剂８－喹啉偶氮槲皮素的合成方法及其理化性质,显色性能和与Ｆｅ（Ⅲ）的显色反应条件,在ＴｗｅｅＮ－８０存在下,ＰＨ＝１０．３的ＮＨ３－ＮＨ４Ｃｌ缓冲介质中,Ｆｅ（Ⅲ）与８－ＱＡＱ的络合物在５００ｎｍ处有最大吸收,表观摩尔吸光系数为１．０６×１０＾５Ｌ·ｍｏｌ＾－１·ｃｍ＾－１,Ｆｅ（Ⅲ）含量在０－２．６μｇ／１０ｍＬ范围内符合比耳定律。在室温下,络合物至少稳定１５ｈ,络合比为１：３     

Speckle characteristics of a broad-area VCSEL in the incoherent emission regime

We present a technique to reduce the speckle contrast of a NIR broad-area VCSEL based on the spatially incoherent emission regime that can be obtained when using the proper driving conditions. We evaluate the efficiency of this technique to reduce the speckle contrast by comparing it with the speckle characteristics in multimode emission under cw operation. Depending on the illumination setup, the incoherent emission regime can lead to a strongly reduced speckle contrast down to 1.3%. This is in agreement with estimates of the expected speckle contrast reduction when three contrast reducing effects are taken into account. These low contrast values make the investigated sources attractive for several applications that suffer from speckle noise.     

Grain boundary potential and charge density at grain boundaries of chemically prepared thin silver sulfide films

The grain boundary potential and interface state charge density at the grain boundaries of silver sulfide (Ag₂S) thin films prepared by chemical conversion of cadmium sulfide (CdS) films have been determined from the dc resistance of the material and are found to be sensitive to annealing. A reduction in the grain boundary potential and the grain boundary charge density of the film has been noticed when the source CdS film is annealed at different temperatures prior to chemical conversion. The variation in the grain boundary charge density of the grown Ag₂S film with source annealing temperature has been found to be similar to that of thin cadmium sulfide film, reported earlier. An additional low temperature heat treatment of the sample results in an enhancement in the charge density at the grain boundaries. The change in the silver vacancy and/or oxygen and sulfur content of the films as revealed from the energy dispersive spectra of the films suggests possible role of film composition on the grain boundary charge density.     

Crystallization and Melting Behavior of Polypropylene in Presence of Hydrogenated Dicyclopentadiene

A study of miscibility, morphology, crystallization, and dynamic mechanical properties of polypropylene in the presence of a low-molecular-weight compound, hydrogenated dicyclopentadiene (DCPD), is described. Differential scanning calorimetry (DSC), optical microscopy (OM), and dynamic mechanical analysis (DMA) were used for this purpose. The blends exhibit composition-dependent melting point depression and reduced degree of crystallinity. Isothermal crystallization measurements show that the crystallization takes place at a lower temperature with an increase in crystallization half time with respect to pristine PP. This indicates retardation in crystallization of PP in the blends. The observed changes in the melting and crystallization behaviors are ascribed to the miscibility of the two components. The interaction parameter estimated using the Flory–Huggins equation shows negative values, suggesting the presence of strong specific interaction between PP and DCPD.     

The Effects of Polarization and Non-Linearity on the Performance of WDM System with Optical Cross-Connects

The performance of a wavelength division multiplexing (WDM) system with optical cross-connects (OXCs) and in the presence of polarization and nonlinear effects was analyzed. We determined the effect of PMD and PDL; nonlinearity such as XPM, SPM, and FWM; and CD on the system performance. We found that the system outage probability is highest at DGD threshold for the respective maximum eye closure (EC). We showed that the allowable DGD depends on the time slot for one bit T, which is the inverse of the network bit rate. Wider T is more immune to large PMD with the EC still maintained at the same level since DGD/T is unchanged. Our analysis also indicated that as DGD increases, BER increases. The BER also increases with increase in PDL and further increases with the presence of XPM, SPM, FWM, and CD.     

Structural characterization of ultrathin Cr and Sc films for soft X-ray mirrors

The structure of multilayers of ultrathin scandium (Sc) and chromium (Cr) films has been characterized by means of transmission electron microscopy (TEM). Face centered cubic Sc was found both in magnetron sputtered thin Sc layers on Si(0 0 1) and in Cr/Sc multilayers for soft X-ray mirrors. The single Sc and Cr layers are polycrystalline with randomly oriented grains, while Sc and Cr within the Cr/Sc multilayer show a strong [0 0 1] texture in the deposition direction. From high-resolution images the orientation-relationship at the Cr/Sc interfaces could be deduced as: Sc_[110]//Cr_[100] and Sc_[010]//Cr_[110], which was confirmed by image simulations.     

庆大霉素与水溶性CdTe量子点的荧光共振能量转移作用

以巯基丙酸(mercaptopropionic acid,MPA)为稳定剂合成水溶性CdTe最子点(quantum dots,QDs),以CdTe QDs作为能量供体.庆大霉素(Gentamycin,GT)作为能垦受体,建立了荧光共振能量转移(fluorescence resonance energy transfer,FRET)体系.在690 nm处可见发射峰,半峰宽约10 nm,在一定范围内荧光强度与GT的含量旱线性关系,线性范围为2～20 mg·L-1,相关系数r=0.986 7.优化了不同的激发波长、pH、离子强度、时间和温度等凼素对反应的影响,并应用傅里叶变换红外光谱(Fourier transform infrared spectroscopy,FTIR)和高效液相色谱(high-performance liquid chromatography,HPLC)分别表征了化学结构和相对专一性.结果表明巯基丙酸的巯基中S原子和羧基中氧原子与纳米微粒表面的富Cd离子发生了配位作用,CdTe QDs与GT的耦合主要是通过量子点周围巯基丙酸羧基(-COOH)中的氧原子与GT的胺基(-NH2)形成分子问氧键实现的;GT与CdTe QDs的结合率为0.35:1.研究表明GT可以作为检测CdTe QDs标记牛血清白蛋白(bovine serum albumin,BSA)的荧光增敏剂,荧光强度值增强6倍,应用前景广阔.     

TL, OSL and ESR studies on beryllium oxide

Electron spin resonance (ESR) studies were carried out to identify the defect centres responsible for the thermoluminescence (TL) and optically stimulated luminescence (OSL) processes in BeO phosphor. Two defect centres were identified in irradiated BeO phosphor by ESR measurements, which were carried out at room temperature and these were assigned to an O⁻ ion and Al²⁺ centre. The O⁻ ion (hole centre) correlates with the main 190 °C TL peak. The Al²⁺ centre (electron centre), which acts as a recombination centre, also correlates to the 190 °C TL peak. A third centre, observed during thermal annealing studies, is assigned to an O⁻ ion and is related to the high temperature TL at 317 °C. This centre also appears to be responsible for the observed OSL process in BeO phosphor.     

垂直腔面发射激光器的结构生长及特性研究

在偏〈111〉A 2°的GaAs (100) 衬底上生长了Al0.9Ga0.1As /Al0.2Ga0.8As周期结构的垂直腔面发射激光器（VCSEL）外延片P 型DBR的周期数为24.5对,N型DBR的周期数为34.5对.用光荧光 (PL) 谱、扫描电子显微镜 (SEM)和X射线双晶衍射 (XRD) 方法对VCSEL的光学特性和结构特性进行了分析室温量子阱材料的PL谱峰值波长为837.0 nm,半高宽达到28.9 nm在X射线双晶衍射回摆曲线中,除了“0”级衍射峰外,还观察到一级和二级卫星峰.“0”级双晶衍射峰的半高宽为12.56弧秒(″),衬底GaAs的衍射峰半高宽为11.79″.“0”级衍射峰半高宽与衬底GaAs的衍射峰半高宽比较接近,表明晶格具有很高的完整性.实验结果表明腔模波长为837.2 nm,腔模波长与PL谱峰值波长相匹配.     

A detailed analysis of cross-phase modulation effects on OOK and dpsk optical WDM transmission systems in the presence of GVD,SPM, and ASE noise

A performance analysis is carried out to evaluate the effect of cross-phase modulation (XPM) on a dispersion-managed 20 Gb/s optical wavelength-division multiplexing (WDM) transmission system using either the on-off keying (OOK) or the different-phase-shifting keying (DPSK) modulation, in the presence of the group-velocity dispersion (GVD), self-phase modulation (SPM), and amplified spontaneous emission (ASE). It is found that to achieve a bit error rate (BER) of 10⁻⁹ at a distance of 160 km, a 1.0 dB XPM power penalty is incurred for input channel power of 3 dBm in the OOK transmission and 7 dBm in the DPSK transmission. The power penalty increases with input channel powers and is inversely proportional and exhibits oscillations with respect to the channel separation. The oscillation is evenly spaced for the DPSK but not for the OOK and suggests the presence of optimum separation values. The XPM penalty decreases when a high dispersion fiber is used and increases linearly with increasing dispersion slope. Small residual dispersion can reduce the penalty of nonlinear effects.     

The effect of phonon anisotropic scattering on the thermal conductivity of silicon thin films at 300K and 400K

Previous studies have shown that anisotropy in phonon transport exist because of the difference in phonon dispersion relation due to different lattice directions, as observed by a difference in in-plane and cross-plane thermal conductivities. Our current work intends to study the effect of anisotropy scattering on silicon thermal conductivity at 300 K and 400 K. We adopt the Henyey and Greenstein probability density function in our phonon Monte Carlo simulation to investigate the effect of highly forward and backward scattering events. The impact of applying the anisotropy scattering using this approach is discussed in detail. While the forward and backward scattering will increase and decrease thermal conductivity respectively, the extent of the effect is non-linear such that forward scattering has a more obvious effect on thermal conductivity than backward scattering.