掺铒光纤放大器中上转换过程的影响

掺杂浓度的提高影响了掺铒光纤放大器(EDFA)的性能,对经典Giles模型提出了新的要求。首先研究了高掺杂下铒离子距离较小引起的上转换过程的机理,通过优化速率方程模型分析了上转换过程对EDFA的影响,得出了在泵浦光和信号光远远大于ASE光的假设下泵浦光和信号光沿光纤长度变化的近似表达式,并将该近似分析解与解析解进行了比较。仿真结果表明上转换过程会降低随光纤传输的信号光和泵浦光,影响EDFA的放大性能,并得出了当掺铒浓度大于2.95×1025m-3时,上转换过程的影响不能忽略的结论。     

Design and Fabrication of 1.06 μm Resonant-Cavity Enhanced Reflective Modulator with GaInAs/GaAs Quantum Wells

A resonant-cavity enhanced reflective optical modulator is designed and fabricated, with three groups of three highly strained InGaAs/GaAs quantum wells in the cavity, for low voltage and high contrast ratio operation. The quantum wells are positioned in antinodes of the optical standing wave. The modulator is grown in a single growth step in an molecular beam epitaxy system, using GaAs/AlAs distributed Bragg reflectors as both the top and bottom mirrors. Results show that the reflection device has a modulation extinction of 3 dB at -4.5 V bias.     

A Novel Organic—Inorganic Complex：Synthesis and Crystal Structure of [Ca（DMSO）5（H2O）]2 SiMo12O40

It is becoming a focus to synthesize and assemble organic-inorganic materials, especially, to synthesize charge-transfer complexes formed by polyoxometalate and organic donors. They have attracted much attention because such complexes are active in their electric, magnetic and optic properties1-4, many investigations about them have been done and some crystal structures of them were reported5-6. But, the disadvantage of these crystals is instability at room temperature. According to the view…     

A Novel Green Preparation of a, a''''-Bis (substituted benzylidene)-cycloalkanones Promoted by FeCl_3 6H-2O in Ionic Liquid

a, a'-Bis(substituted benzylidene)cycloalkanones were efficiently prepared from cycloalkanones and benzaldehydes in [bmim][BF4] by using iron(III) chloride hexahydrate as a catalyst. It is shown that [bmim][BF4] and iron(III) chloride hexahydrate can be quantitatively recovered and be reused effectively for many times. Compared with the known methods, this novel process has the advantage of being an envkonmentally benign process together with good yields and mild reaction conditions.     

Studies of a new series of ion-pair complexes [Mo(dtc)_4][Ln(dtc)_4] (Ln=La-Er,exp.Pm)

A new series of ion-pair complexes [Mo(dtc)4][Ln(dtc)4] (Ln=La-Er, exp. Pm) were synthesized from MoCl5, LnCl3 and Nadtc in anhydrous methanol. The crystal structures of the four complexes, [Mo(dtc)4][Ln(dtc)4] (Ln=Nd, Sm, Ho and Er) have been determined by X-ray diffraction. Spectroscopic properties of all these complexes are also discussed here.     

镧系离子与L-羟脯氨酸、DL-瓜氨酸配位作用研究

稀土与体内广泛存在的生物配体氨基酸的配位作用，尤其是三元体系的研究对于阐明稀土元素在体内的存在形态及探索稀土生物效应具有重要意义．羟脯氨酸和瓜氨酸均是人体中存在的重要氨基酸，它们在人体血浆中的浓度与必需的氨基酸相近［‘j．稀土与氨基酸配位作用的研究已有较多报道「’‘，但模拟生理条件下稀土离子与羟脯氨酸、瓜氨酸的二元、三元配合物的PH电位法研究尚未见报道．本文报道在模拟生理条件下（37C，0·15mol／LNaCI）湖系离子（Pm和Lu除外）与上述2种氨基酸的二元及三元配合物PH电位法研究结果．1实验部分1．1试剂和仪…     

含有羧基配体的蝎型钒氧配合物的合成、结构及其热分解动力学

设计合成了两种新型的以聚吡唑硼酸盐、氨基酸为配体的钒氧配合物VO[phCH2CH(NH2)COO][HB(pz)3](1)和VO(3,5-Me2pz)[HB(3,5-Me2pz)3](CH3COO)(2). 通过元素分析、红外光谱对配合物进行了表征, 并利用单晶X射线衍射技术解析了它们的结构. 非等温热分解动力学研究表明, 配合物1和2的热分解反应都是分两步进行的. 通过计算, 配合物1热分解的第一步反应的可能机理为成核与生长(n=1/4); 第二步反应的可能机理为化学反应. 其非等温动力学方程分别为, dα/dT=(A/β)e-E/RT(1/4)(1-α)[-ln(1-α)]-3 和dα/dT=(A/β)e-E/RT(1-α)2. 分解反应的表观活化能分别是223.52 和331.94 kJ·mol-1; 指前因子ln(A/s-1)分别是49.67 和57.50. 配合物2 热分解的第一步反应的可能机理为化学反应; 第二步反应的可能机理为成核与生长(n=1/2). 其非等温动力学方程分别为, dα/dT=(A/β)e-E/RT(1-α)2, 和dα/dT=(A/β)e-E/RT(1/2)(1-α)[-ln(1-α)]-1. 分解反应的表观活化能分别是300.56 和444.72 kJ·mol-1; 指前因子ln(A/s-1)分别是75.53 和92.50.     

V_2O_5/C催化氧化乙二醛制备乙醛酸

利用等体积浸渍法制备了V2O5/C催化剂,并应用于乙二醛的液相氧化反应,采用XRD、TEM手段对催化剂进行了物化性质表征.结果表明,V2O5/C对乙二醛的氧化表现出较高的催化活性和乙醛酸选择性,反应10h,乙二醛的转化率达29.2%,乙醛酸得率13.6%.与贵金属Pd-Bi/C催化剂相比,V2O5/C催化剂的稳定性和重复使用效果都比较好.     

激光光散射研究丙烯酰胺-二甲基二烯丙基氯化铵共聚物的溶液行为

用激光光散射技术表征了阳离子含量受控的丙烯酰胺 二甲基二烯丙基氯化铵共聚物 (简称P(AM DMDAAC) )在 0 1mol LNaCl溶液中的基本参数和溶液行为 .表观基本参数 : Mw ,app =5 0 4× 10 5g·mol- 1 、app =39 9nm和A2 ,APP =1 5× 10 - 4cm3·mol·g- 2 .动态光散射研究结果表明 ,扩散系数Dt 与角度、浓度皆呈非线性依赖关系 ,当C >C 或在较大的散射角域 ,Dt 偏离线性关系所预示的理论值而向减小的方向发展 ,表明存在缔合物 ;流体力学半径Rh 分布有大、小两个范围 ,并随温度升高向小尺寸方向发展 ,证明了体系中存在缔合行为以及升温的解缔合作用 .在一定条件下 ,“亚稳定性”的存在有力地旁证了体系的缔合行为     

Synthesis, crystal structure and characterization of a 2-D network organic-inorganic hybrid polymer with [α-BW12O40]5- as building blocks

A two-dimensional network compound [Ce(DMF)4(H2O)][α-BW12O40]·H2O·(HDMA)2 (HDMA = protoned dimethylamine, DMF = N,N-dimethylformamide) was synthesized from α-H5BW12O40·nH2O, Ce(NO3)3·6H2O and DMF and characterized by IR, UV spectra and TG-DTA. The result of the X-ray single crystal diffraction indicates that the crystal is monoclinic, space group P21/n, with unit cell dimensional: a = 1.1983(3), b = 2.4216(5), c = 1.9517(4) nm, β = 92.91(3)°, Z = 4, R1 = 0.07710, wR2 = 0.1416. Structural analysis indicates that every [Ce(DMF)4(H2O)]3-building block is surrounded by three adjacent [α-BW12O40]5-polyanions, meanwhile, every [α-BW12O40]5-polyanion interconnects with three neighboring [Ce(DMF)4(H2O)]3+ subunits, by making use of which two-dimensional network structure can be constructed. The result of thermogravimetric analysis manifests that the title compound has two-stage weight loss and the decomposition temperature of the title polyanionic framework is 560℃. The electrochemical analysis shows the title polyanion has three-step redox processes in the pH = 4-7 media.