基于氧化镍背接触缓冲层碲化镉薄膜太阳电池的研究

采用电子束蒸发法制备了NiO薄膜,并对其作为碲化镉薄膜太阳电池背接触缓冲层材料进行了相关研究.NiO缓冲层的加入使得碲化镉太阳电池开路电压显著增大.通过X射线光电子能谱测试得到的NiO/CdTe界面能带图表明NiO和CdTe的能带匹配度很好.NiO是宽禁带P型半导体材料,在电池背接触处形成背场,减少了电子在背表面处的复合,从而提高电池开路电压.通过优化NiO薄膜厚度,制备得到转换效率为12.2%、开路电压为789 mV的碲化镉太阳电池.研究证实NiO是用来制备高转换效率、高稳定性碲化镉薄膜太阳电池的一种极有前景的缓冲层材料.     

可控合成Pd-Pt八面体框架结构作为高效的氧还原反应催化剂

Pt-based nanoframes represent a class of promising catalysts towards oxygen reduction reaction. Herein, we, for the first time, successfully prepared Pt-Pd octahedral nanoframes with ultrathin ridges less than 2 nm in thickness. The Pt-Pd octahedral nanoframes were obtained through site-selected deposition of Pt atoms onto the edge sites of Pd octahedral seeds, followed by selective removal of the Pd octahedral cores via chemical etching. Due to that a combination of three-dimensional opens geometrical structure and Pt-skin surface compositional structure, the Pt-Pd octahedral nanoframes/C catalyst shows a mass activity of 1.15 A/mg_Pt towards oxygen reduction reaction, 5.8 times enhancement in mass activity relative to commercial Pt/C catalyst (0.20 A/mg_Pt). Moreover, even after 8000 cycles of accelerated durability test, the Pt-Pd octahedral nanoframes/C catalyst still exhibits a mass activity which is more than three times higher than that of pristine Pt/C catalyst.     

一氧化二氮分子位于775 nm的6υ3振动泛频跃迁的高精密光腔衰荡光谱

Transitions of the 6υ₃ overtone band of ¹⁴N₂ ¹⁶O near 775 nm have been studied by continuous-wave cavity ring-down spectroscopy. Line positions and intensities were derived from a fit of the line shape using a hard-collisional profile. The line positions determined with absolute accuracy of 5×10^-4 cm^-1 allowed us to reveal finer ro-vibrational couplings taking place after J>14 except a strong anharmonic interaction identified by the effective Hamiltonian model. The absolute line intensities have also been retrieved with an estimated accuracy of 2% for a majority of the unblended lines. A new set of ro-vibrational and dipole moment parameters were derived from the experimental values. A comparison between the line positions and intensities of the 6υ₃ band obtained in this work and those from previous studies is given.     

表面桥氧空位对甲醛在二氧化钛表面吸附的影响

Oxygen vacancy (O_v) has significant influence on physical and chemical properties of TiO₂ systems,especially on surface catalytic processes.In this work,we investigate the effects of O v on the adsorption of formaldehyde (HCHO) on TiO₂(110) surfaces through firstprinciples calculations.With the existence of O_v,we find the spatial distribution of surface excess charge can change the relative stability of various adsorption configurations.In this case,the bidentate adsorption at five-coordinated Ti (Ti_5c) can be less stable than the monodentate adsorption.And HCHO adsorbed in O_v becomes the most stable structure.These results are in good agreement with experimental observations,which reconcile the long-standing deviation between the theoretical prediction and experimental results.This work brings insights into how the excess charge affects the molecule adsorption on metal oxide surface.     

固体氧化物燃料电池堆多物理场耦合模拟的高效电化学-传质耦合算法

A multiphysics model for a production scale planar solid oxide fuel cell (SOFC) stack is important for the SOFC technology, but usually requires an unpractical amount of computing resource. The major cause for the huge computing resource requirement is identified as the need to solve the cathode O₂ transport and the associated electrochemistry. To overcome the technical obstacle, an analytical model for solving the O₂ transport and its coupling with the electrochemistry is derived. The analytical model is used to greatly reduce the numerical mesh complexity of a multiphysics model. Numerical test shows that the analytical approximation is highly accurate and stable. A multiphysics numerical modeling tool taking advantage of the analytical solution is then developed through Fluent®. The numerical efficiency and stability of this modeling tool are further demonstrated by simulating a 30-cell stack with a production scale cell size. Detailed information about the stack performance is revealed and brie y discussed. The multiphysics modeling tool can be used to guide the stack design and select the operating parameters.     

实时观测绿脓杆菌素溶解氢氧化铁

绿脓杆菌素是绿脓杆菌分泌的铁载体,它可以帮助细菌在体外有效摄取铁.为了观测绿脓杆菌素与铁的结合作用,提纯了游离态的绿脓杆菌素,并采用动态激光光散射来观察绿脓杆菌素和氢氧化铁的相互作用.实时观测光散射数据分析表明绿脓杆菌素可以直接和Fe（OH）₃作用形成复合物,这种复合物会自身逐渐降解直到完全消失.实验证明绿脓杆菌素不仅能够和铁离子相结合,还可以通过溶解氢氧化铁来帮助细菌在缺铁环境中生存.     

水中ClF的分子动力学模拟:液体中的卤键作用

Does the halogen bonding interaction co-exist in liquid when it competes with the hydrogen bonding interaction? The classical molecular dynamics simulations for the solvation properties of ClF molecule in water are performed with the Lennard-Jones plus Coulomb electrostatic potential parameters that are optimized with ab initio interaction energy calculations for the pre-reactive H₂O…ClF complex. We find that the halogen bonding interactions occur between O and Cl atoms and have the comparable strength and population with respect to the hydrogen bonding interactions of Cl…H.     

1-碘丙烷分子的电子动量谱学研究：自旋-轨道耦合效应与分子内轨道相互作用

利用不对称不共面电子动量谱仪,在2.5 keV碰撞能量下,采用高精度的SAC-CI方法计算了1-碘丙烷分子束缚能谱,同时采用Hartree-Fock、B3LYP/aug-cc-pVTZ（C,H）6-311G＊＊（I）方法计算其电子动量分布. 并对电离能峰进行了标示. 结合非相对论与相对论计算方法以及自然键轨道分析,对最外层两个轨道（碘的5p孤对）的自旋-轨道耦合效应与分子内轨道相互作用进行了比较. 两种相互作用对电子动量分布的不同影响是可观的. 实验结果与相对论计算的结果一致,表明1-碘丙烷分子内自旋-轨道耦合效应占主导.     

介电力显微镜探测氧化锌纳米线表面吸附分子对电导率的影响

利用场效应晶体管器件和介电力显微镜来研究氧化锌纳米线表面吸附分子对其电导率的影响. 相比于空气中,ZnO纳米线场效应晶体管器件在氮气中电导率更高,介电力显微镜得的介电信号也是在氮气中更大. 影响ZnO纳米线电导率变化的主要原因是表面吸附分子数量的变化,而并不是电极与材料之间接触性质的变化.     

Ar原子偶宇称3p5(2P1/2)nl''[K'']J(l''=1,3)自电离态激发谱线形研究

The even-parity autoionizing resonance series 3p⁵np''[3/2]_1,2, 3p⁵np''[1/2]₁, and 3p⁵nf''[5/2]₃ of Ar have been investigated exciting from the two metastable states 3p⁵4s[3/2]₂ and 3p⁵4s''[1/2]₀ in the photon energy range of 32500-35600 cm^-1 with an experimental bandwidth of ~0.1 cm^-1. The excitation spectra of the even-parity autoionizing resonance series show typical asymmetric line shapes. New level energies, quantum defects, line profile index and resonance widths, resonance lifetime and reduced widths of the autoionizing resonances are derived by a Fano-type line-shape analysis. The line profile index q and the resonance widths Γ are shown to be approximately proportional to the effective principal quantum number n^*. The line separation of the 3p⁵np'' autoionizing resonances is discussed.