MBE-grown Ridge-waveguide InGaAs/InGaAsP Strained Quantum Well Lasers at 2 μm Wavelength

The result of molecular beam epitaxy (MBE)-grown ridge-waveguide InGaAs/ InGaAsP/InP strained quantum well lasers at 2 μm wavelength is reported. The pulsed electrical luminescence spectrum at room temperature is observed with peak wavelength of about 1.98 μm. At 77 K the lasers become lasing in pulse regime, with threshold current of about 18～30 mA, peak wavelength of about 1.87～ 1. 91 μm, and single longitudinal mode operation in the current range of 160～230 mA.     

咪唑封端聚氨酯予聚体改性环氧树脂E-51/双氰双胺固化体系性能研究

以聚丙二醇PPG10 0 0、甲苯二异氰酸酯 (TDI)、咪唑为原料 ,合成了咪唑封端的聚氨酯予聚体 ,简称扩链脲TIEU .利用DSC、粘弹谱仪、冲击试验机及扫描电镜 (SEM)等手段对TIEU改性的环氧树脂E 5 1/双氰双胺(dicy)固化体系的反应活性、动态力学行为、冲击性能、断裂面形态结构进行了系统研究 .实验结果表明 ,改性后的E 5 1 dicy体系反应活性明显提高 ,固化反应的表观活化能由未改性体系的 131kJ mol降至 75～ 80kJ mol.与咪唑促进体系比较结果显示 ,两种固化反应的促进机制具有一定的差异 .另外与未改性体系相比 ,经过改性的环氧树脂体系冲击强度提高 2～ 3倍 ,而玻璃化温度和模量基本不变 ,冲击断面呈韧性断裂     

1—（5—硝基—2—吡啶偶氮）2，7—萘二酚吸光光度法测定微量钴

报道了 1 (5 硝基 2 吡啶偶氮 ) 2 ,7 萘二酚与钴的显色反应 ,结果表明 ,在Tween 80存在下 ,pH 5 .2 6.5时试剂与钴形成稳定的蓝色配合物 ,其最大吸收波长位于 63 5nm ,表观摩尔吸光系数为 6.44× 10 4 L·mol- 1·cm- 1,配合物中钴与试剂的组成比为 1∶2 ,钴浓度在 0 5 μg/10ml范围内服从比耳定律。方法用于标准钢、金川精矿等试样中钴的测定 ,结果满意。     

La(Ⅲ)、Eu(Ⅲ)与HBED配合的紫外差光谱研究

在0.01mol·L     

甲苯硝基衍生物的研究进展

在这篇文章中,首先综述了甲苯硝基衍生物研究的进展,根据这一评论详细地说明了化学转化机理和取代基效应,并对硝基甲苯的选择性氧化进行了简单评述。     

The Aggregates in LB Films of Schiff base Aluminium (III) Complex

Metal complexes, which are composed of metal ions and amphiphile ligands, show some structural peculiarities in Langmuir-Blodgett (LB) films. In the past studies, the metal complexes were mainly composed of the transitional metal ions1,2. The metal ions in IA, IIA and IIIA were seldom mentioned. Further more, the aluminium element is at the position where the typical metal elements transit to the typical non-metal elements in the periodic table of elements and study on the properties of …     

ABO3钙钛矿型复合氧化物光催化活性与B离子d电子结构的关系

在ABO₃钙钛矿型复合氧化物中,B离子的d电子结构对B_3d-O_2p之间的电荷转移能ΔCT及B-O之间的结合能起着关键作用,是影响ABO₃复合氧化物光催化活性的一个重要因素.本文以研磨法和柠檬酸法合成了系列LaBO₃(B=Ti-Co),并结合光催化降解实验和光声光谱图分析得出:LaBO₃光催化活性随B离子3d电子数的递增而逐渐增加.     

A Study on the Color Reaction of Nickel with a New Chromogenic Reagent 1- (5-Nitro-2-Pyridylazo) - 2.7 - Dihydroxy - naphthalene and its Application

There has been study on heterocyclicazo reagent for the determination of microamount of nickel,but no study on the color reactron of nickel with a new chromogenic reagent 1- (5 -nitro - 2 - pyridylazo) - 2.7 - dihydroxy - naphthalene (5- NO₂ - PADN). So, here is a systematic study on condition under which the color reaction takes place. It proved that within PH 5.5~6.5,the maximnm absotption of the reagent lies at 460nm, that of the 2:1 turquoise chelate by 5 - NO₂ - PADN with nickel (Ⅱ) together is 650nm, and the apparent absorptivity is 1.02×10⁵ L · mol^-1 · cm^-1. The proposed method can be applied in the standard steel and the determination of microamounts of nickel in ore with satisfactory results.     

Synthesis of l-(5-Nitro-2-Pyridylazo)-2.7-Dihydroxy-naphthalene and its Color Reaction with Cobalt (Ⅱ)

Pytrdylazo reagent is an important chromogenic reagent. PAN is typical one. The new reagent, l-(5-nitro-2-Pyridylazo)-2.7-dihydroxy-naphthalene (5-NO₂-PADN) has been synthesized by to take up -OH and -NO₂ groups at the PAN, and it was confirmed with IR and elements analysis.     

Studies On Spectroscopy of RE Complexes and Their LB Films

Two series of amphiphilic rare earth complexes are synthesized through molecular design and chemical modification of organic ligands.