熔融Cu55团簇在Cu(010)表面上凝固过程的分子动力学模拟

采用基于嵌入原子方法的分子动力学,模拟了熔融Cu55团簇在Cu衬底(010)表面上以两个不同降温速率降温过程中结构的变化.模拟结果表明,降温速率对团簇结构的变化有很大影响.较快的降温速率使得降温过程中团簇原子具有较低的能量;较慢的降温速率有助于高温时位于衬底内的原子向衬底表面扩散,排列形成面心立方结构.     

Developments of High-Efficiency Flexible Cu（In,Ga）Se2 Thin Film Solar Cells on a Polyimide Sheet by Sodium Incorporation

We present the fabrication of flexible Cu（In,Ga）Se2 （CIGS） solar cells on a polyimide （PI） sheet with and without Na incorporation. A sodium element is incorporated into the CIGS absorber by using a NaF precursor after Mo back contact deposition. X-ray diffraction patterns show that the （112） preferred orientation of the as-grown GIGS films is decreased by Na incorporation. The secondary phase of （Inx,Gal-x）zSe3 is observed for the CIGS films with Na. There is no significant difference in the grain size with and without Na incorporation from surface and cross-sectional SEM images. Additionally, the increase of carrier concentration and decrease of resistivity of CIGS absorber are induced by Na doping. Finally, the flexible CIGS solar cells on PI sheets with efficiency close to 11%, containing Na, are achieved. The improvement of cell efficiency can be attributed to the modified electrical properties of the CIGS film by Na incorporation.     

Multistep excitation of autoionizing states of the samarium atom

In this work, 4f ⁶6pnl and 4f ⁵5d6snl (l=0,2) autoionizing states of the samarium (Sm) atom, especially those with lower principal quantum number, have been studied, using the isolated-core excitation scheme with three dye lasers. In the energy region between 57 990 and 61 030 cm⁻¹, there are 74 autoionizing states of the Sm atom observed. These states can be classified into the autoionization series converging to four different ionization limits. In most cases, the line shapes of these autoionizing states are nearly symmetric, from which the level energies and widths can be easily obtained by fitting the experimental spectra to the Lorentzian profiles. In addition, several spectroscopic properties of these autoionizing states, such as configuration interaction, are also discussed.     

Fabrication of transparent double-walled carbon nanotubes flexible matrix touch panel by laser ablation technique

This study reports on the fabrication of transparent double-walled carbon nanotubes (DWNTs) flexible matrix touch panel using the method of laser ablation. We employed an Nd:YAG laser (1064 nm) to pattern transparent DWNT thin film pre-coated on a PET substrate and successfully fabricated a flexible matrix touch panel. By increasing the laser energy, the ablation depth of transparent DWNT flexible thin film is increased but the sheet resistance (Ω/sq) is decreased. When the laser energy intensity reaches 117 mJ/cm², the DWNTs can be completely ablated from transparent DWNT flexible thin film. This method is rapid, simple, applicable to large-area processing and thus is potential for mass production.     

A Monte Carlo study for the shielding of γ backgrounds induced by radionuclides for CDEX

The CDEX(China Dark matter EXperiment)Collaboration will carry out a direct search for WIMPs(Weakly Interacting Massive Particles)using an Ultra-Low Energy Threshold High Purity Germanium(ULE-HPGe)detector at the CJPL(China JinPing deep underground Laboratory).A complex shielding system was designed to reduce backgrounds and a detailed GEANT4 Monte Carlo simulation was performed to study the achievable reduction of T rays induced by radionuclides and neutron backgrounds by D(γ,n)p reaction.Furthermore,the upper level of allowed radiopurity of shielding materials was estimated under the constraint of the expected goal.Compared with the radiopurity reported by other low-background rare-event experiments,it indicates that the shielding used in the CDEX can be made out of materials with obtainable radiopurity.     

Ti表面修饰纳米TiO2膜电极的电催化活性

用电化学合成法在Ti表面修饰一层纳米TiO₂膜,TEM和XRD测试表明晶型为锐钛矿型,晶粒平均尺寸为25nm.用循环伏安法、循环方波伏安法和电解合成法研究了纳米TiO₂膜电极在硫酸介质中的氧化还原行为以及对硝基苯还原的电催化活性。结果表明,纳米TiO₂膜电极具有异相氧化还原催化行为,膜中的Ti(Ⅳ)/Ti(Ⅲ)作为媒质间接电还原硝基苯为对氨基苯酚,收率和电流效率分别达91.6%和95.2%.     

TiO2-V2O5纳米复合膜的制备及防腐蚀性能

采用溶胶-凝胶法和浸渍提拉技术在316L不锈钢表面构筑纳米TiO₂薄膜和“夹心”式TiO₂-V₂O₅复合薄膜（TiO₂/TiO₂-V₂O₅/TiO₂）, 应用AFM和XRD表征膜的形貌及纳米颗粒的晶型. 结合光、电化学方法测试了复合膜在0.5 mol•L^-1 NaCl溶液(pH=4.6)中暗态或紫外照射条件下的防腐蚀性能. 结果表明, TiO₂/TiO₂-V₂O₅/TiO₂复合膜具有双重保护功能, 即在紫外光照下可以起到光生阴极保护的作用, 特别是当停止光照后, 光生电位仍可维持在较低的电位长达6 h以上. 同时作为表面阻挡层, 可显著提高金属的耐腐蚀性.     

Saturation effects on Ba 6phi （l=0, 2） and 6pnk （｜M｜= 0, 1） autoionization spectra

Using a three-step laser saturation excitation technique, the saturation effects on the Ba 6pns （J = 1） and 6pad （J = 1, 3） autoionization spectra are observed systemically in zero field. These saturation spectra are introduced to determine the high n members of 6pnl （l = 0, 2） autoionizing series and are used to analyse the channel interactions among the autoionizing series in zero field. Furthermore, the saturation excitation technique is applied to the electric field case, in which the saturation spectra of Ba 6pnk （｜M｜= 0, 1） autoionizing Stark states are measured. Most of these saturation spectra are observed for the first time so far as we know, which indicate the mixing of the autoionizing states in the electric fields.     

模拟水中白铜B30耐蚀性影响因素的光电化学研究

用动电位伏安法和光电化学方法对模拟水中白铜B30耐蚀性影响因素进行了研究. 白铜B30表面膜显示p-型光响应, 光响应来自电极表面的Cu₂O层, 在模拟水溶液中表面膜的半导体性质会发生转变, 由p-型转为n-型; 在不同 Cl^－, SO₄^2－浓度的模拟水溶液中, 电位正向扫描时呈现阳极光电流, 电位负向扫描时随着Cl^－, SO₄^2－离子浓度的增加, 光响应由p-型向n-型转变, 阳极光电流峰面积与阴极光电流峰面积之比增大, 耐蚀性能降低; 随着温度的升高, 白铜B30的耐蚀性能降低; 在pH＝7～9之间, 其耐蚀性能随着pH的升高而提高, 当pH＞9时, 其耐蚀性能随着pH的升高呈降低趋势.