Electrical properties of LiNbO3 (electrolyte)/Cu (anode) bi-layers

In this work specific film structures of Li-Nb-O/Li/Li-Nb-O are investigated by AC Impedance Spectroscopy measurements at different temperatures. This gives the opportunity to investigate properties of the material itself and, at the same time, to consider the influence of the grain boundaries on the ionic behavior of the polycrystalline Lithium Niobate. On the other hand, LiNbO3/Li/Cu multi-layers are studied as electrolyte/anode bi-layers and potential parts of "Li-free" microbatteries. The Li deficiency in the as deposited Li-Nb-O films is cured by forming a "sandwich" of Li-Nb-O/Li/Li-Nb-O, which after annealing becomes ionic conductor. The electrical behavior of an annealed film depends on two sources. The first is due to properties of the material itself and the second is based on the network of the grain boundaries. The average size of the grains is strongly influenced by the structure of the ohmic-contact/substrate. The electrical behavior of the electrolyte/anode interface of the "Li-free" structure LiNbO3/Li/Cu/Au is very similar to the impedance measurements of the single LiNbO3 single films. The whole multilayer structure, though, presents a third relaxation time which is consistent of a small resistance. This resistance is independent of temperature and it seems that is due to the metallic interface Li/Cu/Au. © 2010 Elsevier B.V. All rights reserved.

Oscillatory change of SR-protein kinase activities during oocyte maturation meiosis in fish

The SR-protein kinase activity was analyzed and the cytological changes were observed during oocyte maturation in bisexual transparent color crucian carp ( Carassius auratus color variety). The results revealed that the SR-protein kinase activity was sensitive to the artificially induced spawning hormones, and the change of oscillatory activity was similar to that of the maturation-promoting factor (MPF) kinase that regulates meiotic cell cycle in fish.

Role of Bi3+ ions for Er3+ ions efficient 1.54 mu m light emission in Er/Bi codoped SiO2 thin film prepared by sol-gel method

Er/Bi codoped SiO2 thin films were prepared by sol-gel method and spin-on technology with subsequent annealing process. The bismuth silicate crystal phase appeared at low annealing temperature while vanished as annealing temperature exceeded 1000 degrees C, characterized by X-ray diffraction, and Rutherford backscattering measurements well explained the structure change of the films, which was due to the decrease of bismuth concentration. Fine structures of the Er3+-related 1.54 mu m light emission (line width less than 7 nm) at room temperature was observed by photoluminescence (PL) measurement. The PL intensity at 1.54 gm reached maximum at 800 degrees C and decreased dramatically at 1000 degrees C. The PL dependent annealing temperature was studied and suggested a clear link with bismuth silicate phase. Excitation spectrum measurements further reveal the role of Bi3+ ions for Er3+ ions near infrared light emission. Through sol-gel method and thermal treatment, Bi3+ ions can provide a perfect environment for Er3+ ion light emission by forming Er-Bi-Si-O complex. Furthermore, energy transfer from Bi3+ ions to Er3+ ions is evidenced and found to be a more efficient way for Er3+ ions near infrared emission. This makes the Bi3+ ions doped material a promising application for future erbium-doped waveguide amplifier and infrared LED

New observations on the pressure dependence of luminescence from Eu2+-doped MF2 (M = Ca, Sr, Ba) fluorides

The luminescence from Eu2+ ions in MF2 (M = Ca, Sr, Ba) fluorides has been investigated under the pressure range of 0-8 GPa. The emission band originating from the 4f(6)5d(1) -> 4f(7) transition of Eu2+ ions in CaF2 and SrF2 shows the red-shift as increasing pressure with pressure coefficients of -17 meV/GPa for CaF2 and -18 meV/GPa for SrF2. At atmospheric pressure, the emission spectrum of BaF2:Eu2+ comprises two peaks at 2.20 and 2.75 eV from the impurity trapped exciton (ITE) and the self-trapped exciton (STE), respectively. As the pressure is increased, both emission peaks shift to higher energies, and the shifting rate is slowed by the phase transition from the cubic to orthorhombic phase at 4 GPa. Due to the phase transition at 4-5 GPa pressure, the ITE emission disappears gradually, and the STE emission is gradually replaced by the 4f(6)5d(1) -> 4f(7) transition of Eu2+. Above 5 GPa, the pressure behavior of the 4f(6)5d(1) -> 4f(7) transition of EU2+ in BaF2: EU2+ is the same as the normal emission of Eu2+ in CaF2 and SrF2 phosphors.

Design and optimization of photonic crystal coupling layer for bi-color quantum well infrared photodetectors

Finite difference time domain (FDTD) method is used for the simulation and analysis of electromagnetic field in the top coupling layer of GaAs/AlGaAs quantum well infrared photodetector (QWIP). Simulation results demonstrated the coupling efficiencies and distributions of electromagnetic (EM) field in a variety of 2D photonic crystal coupling layer structures. A photonic crystal structure for bi-color-QWIP is demonstrated with high coupling efficiency for two wavelengths.

丙烯选择氧化和氨氧化钼铋催化剂作用机理的研究

为了深入研究丙烯选择氧化和氨氧化剂的作用机理。探索不同金属离子的催化作用，催化剂的结构、性质与活性的关系。我们应用共沉淀方法制备了α－钼酸铋，γ－钼酸铋，Bi_3(FeO_4)(MoD_4)_2土业催化剂Mo_(12)BiFe_3Ni_(2.5)Co_(4.5)Pa_5K_(0.107)O_(55)+50%SiO_2，Bi_3FexM_(0.3-x)O_n催化剂体系，浸Bi钼酸铁体系，M_7~(24)Fe_3BiMo_(12)O_(96)(M~(2+) = Mg, Ni, Co, Cu, Pb, Sr)体系的催化剂。测定了这些催化剂的X射线衍射数据、IR，Raman，ESCA，Mossbauer等，研究了这些催化剂的结构、组成、物理化学性质。同时考察了这些催化剂对丙烯氨氧化的催化作用，并试图把催化剂的性质与催化作用关联起来。同时，为了进一步研究催化剂的表面活性相、活性中心的性质，丙烯氧化和氨氧化中的表面中间体的形式和键合情况。我们使用了丙烯、丙烯醇、氨、丙烯胺作为分子探针，研究了这些分子的程序升温脱附情况，以便了解钼铋催化剂的催化作用。浸Bi钼酸铁研究说明，Bi可能是丙烯α氢脱除的活性中心。Mo-O多面体起丙烯吸附、氧或氮插入活性中心的作用。由于钼酸铁晶格的敞开性和弹性。Bi进入了钼酸铁晶格，形成了Bi嵌钼酸铁的表层结构。成为对丙烯选择氧化的催化剂。钼酸铁由于Fe~(3+)的部分填充d电子结构，是一种使双键断裂，进行深度氧化的催化剂。Bi进入Fe_2(MoO_4)_3表层的缺陷，形成Bi = o-O-Mo = o对，使深度氧化中心变成选择氧化中心。Bi_3Fe_xMo_(3-x)O_n体系中，随着Fe的加入，形成了Mo-Bi-Fe三元化合物。该化合物比Bi_2Mo_2O_9具有更高的活性和选择性。晶格中Fe~(3+)的存在，将促进P型电导，这时Fe~(3+)相当于受主杂质杂质，降低了费米能级。而丙烯的吸附活化形成烯丙基是一给电子过程。因此，Fe~(3+)的存在将加快丙烯活化吸附的速度，也就加速了反应。并且，Fe~(3+)/Fe~(2+)的氧化还原对存在，能快速接受Mo或Bi上的电子，保持Mo和Bi的氧化态，有利于反应的进行。同时，Fe~(2+)具有较低的电负性，能起到提供氧吸附、进行再氧化的中心的作用。把催化剂的电子提供给氧，同时把晶格氧输送到还原位上。这种多功能作用的协合，可能是Mo-Bi-Fe体系高活性和高选择性的原因。丙烯吸附中，所有催化剂都存在可连吸附中心和不可逆吸附中心。丙烯的吸附是活化解离吸附。不同催化剂的丙烯和丙烯醛的脱附情况相似。说明不同催化剂的丙烯吸附中心，丙烯醛或（丙烯腈）生成中心可能是相同的。丙烯醛脱附峰的存在，说明催化剂的晶格氧离子确能与丙烯作用生成丙烯醛。丙烯醇和丙烯胺的脱附说明，都存在可逆吸附和不可逆吸附两种类型。它们在催化剂表面的吸附是活化解离化学吸附，其吸附中心可能与丙烯选择氧化和氨氧化中的丙烯醛（或丙烯腈）生成中心相同。丙烯氧化反应中，烯丙基氧插入形成的Q－O键合物中间体，与丙烯醇解离吸附形成的表面吸附物种（Mo-O-CH_2-CH = CH_2）相同。同样，丙烯胺解离吸附形成的表面物种（Mo-NH-CH_2-CH = CH_2），可能与丙烯氨氧化中烯丙基Q－NH键合而成的中间体相同。这两种中间体，对选择性生成丙烯醛和丙烯腈起决定作用。NH_3的吸附存在两种可逆吸附类型。而不可逆吸附在高温区以N_2和H＿2O脱附出来。NH_3在催化剂的解离吸附形成NH_2基。温度升高继续脱氢形成NH基。该NH基会插入烯丙基，形成（Mo-NH-CH_2-CH = CH_2）中间体，其继续反应形成丙烯腈。