Cerium oxide nanoparticles protect primary mouse bone marrow stromal cells from apoptosis induced by oxidative stress

The sintering of a silver (Ag) nanoparticle film by laser beam irradiation was studied using a CW DPSS laser. The laser sintering of the Ag nanoparticle thin film gave a transparent conductive film with a thickness of ca. 10 nm, whereas a thin film sintered by conventional heat treatment using an electronic furnace was an insulator because of the formation of isolated silver grains during the slow heating process. The laser sintering of the Ag nanoparticle thin film gave a unique conductive network structure due to the rapid heating and quenching process caused by laser beam scanning. The influences of the laser sintering conditions such as laser scan speed on the conductivity and the transparency were studied. With the increase of scan speed from 0.50 to 5.00 mm/s, the surface resistivity remarkably decreased from 4.45 × 10⁸ to 6.30 Ω/sq. The addition of copper (Cu) nanoparticles to silver thin film was also studied to improve the homogeneity of the film and the conductivity due to the interaction between the oxidized surface of Cu nanoparticle and a glass substrate. By adding 5 wt% Cu nanoparticles to the Ag thin film, the surface resistivity improved to 2.40 Ω/sq.     

RF and field measurements of the SSC-LINAC RFQ

The 53.667 MHz continuous-wave heavy ion RFQ has been designed and manufactured for the SSC-LINAC project.This four-rod RFQ accelerates ions with maximum mass to charge ratio of 7 from 3.728 keV/u to 143 keV/u.Measurements have been carried out to check the RF performance of the cavity and the quality of the electric field.The S11 of the power coupler is adjusted to better than-44 dB,and the Q0 of the cavity is 6440.The quality of the electric field is evaluated by the perturbation method.The measurement procedure and data analysis will be discussed in detail.The error due to gravity of the perturbation bead has been corrected by averaging the fields in different quadrants.As a result,the unflatness of the electric field is±2.5%,and the dipole field component distributes from 0%to 20%in different longitudinal positions,which indicates the asymmetry of the quadrupole field.The unflatness of the quadrupole field distribution represents a good agreement with the simulation results.High power RF test and beam commissioning of the RFQ are on schedule in early 2014.     

Reservoir Pore Structure Classification Technology of Carbonate Rock Based on NMR T 2 Spectrum Decomposition

The carbonate reservoir has a number of properties such as multi-type pore space, strong heterogeneity, and complex pore structure, which make the classification of reservoir pore structure extremely difficult. According to nuclear magnetic resonance (NMR) T ₂ spectrum characteristics of carbonate rock, an automatic pore structure classification and discrimination method based on the T ₂ spectrum decomposition is proposed. The objective function is constructed based on the multi-variate Gaussian distribution properties of the NMR T ₂ spectrum. The particle swarm optimization algorithm was used to solve the objective function and get the initial values and then the generalized reduced gradient algorithm was proposed for solving the objective function, which ensured the stability and convergence of the solution. Based on the featured parameters of the Gaussian function such as normalized weights, spectrum peaks and standard deviations, the combinatory spectrum parameters (by multiplying peak value and normalized weight for every peak) are constructed. According to the principle of fuzzy clustering, the carbonate rock pore structure is classified automatically and the discrimination function of each pore structure type is obtained using Fisher discrimination analysis. The classification results were analyzed with the corresponding casting thin section and scanning electron microscopy. The study shows that the type of the pore structure based on the NMR T ₂ spectrum decomposition is strongly consistent with other methods, which provides a good basis for the quantitative characterization of the carbonate rock reservoir pore space and lays a foundation of the carbonate rock reservoir classification based on NMR logging.     

Performance and stability studies of inverted polymer solar cells with TiO2 film as a buffer layer

TiO₂ based inverted polymer solar cells (PSCs) with a structure of fluorine-doped tin oxide (FTO)/TiO₂/P3HT:PCBM/PEDOT:PSS/Ag presented excellent air stabilities,; the power conversion efficiency (PCE) of devices exhibited only 15 % decay as compared to the highest value while being exposed in air-condition for more than 20 days. Interestingly, an overall enhancement of PCE from 3.5 % to 3.9 % was observed while the PSCs were exposed in air-condition up to 3 days; the improvement of performance was attributed to the TiO₂ films’ oxygen and water protection effect and the oxidation of Ag, which will benefit to form an effective work function match with the HOMO of P3HT leading to improved ohmic contact. However, the performance slowly decreased when the exposure time remains longer due to the physical adsorbed oxygen. UV–ozone treatment on the TiO₂ films’ leads to the formation of a metal-deficient oxide that results in a decreased PCE for the devices. Finally, X-ray photo-emission spectroscopy (XPS) was used to analyze the compositional changes of the TiO₂ films while they were exposed in air-condition or treated by UV–ozone.     

A facile way to fabricate a superamphiphobic surface

Compared to superhydrophobic surfaces, superamphiphobic surfaces possess more potential applications but are difficult to fabricate. Herein, to address this problem, we describe a simple method to fabricate a superamphiphobic surface based on a CNTs–SiO₂ hybrid material. The CNTs–SiO₂ hybrid material obtained by a sol–gel approach was sprayed onto glass slides to form coatings. After surface fluorination, the sprayed coating displayed superamphiphobicity toward water and a number of organic liquids, such as dodecane. It was found that the time of fluorination slightly influenced the surface wettability of the sprayed coating. We also investigated the role of CNTs and SiO₂ on superamphiphobicity establishment separately, and such information allowed us to engineer surfaces with specific wettability.     

Fabrication of Ag nanodot array over large area for surface-enhanced Raman scattering using hybrid nanoimprint mold made from AAO template

We demonstrated the fabrication of dense hexagonal arrays of Ag nanodots over a large area using a novel nanoimprint-based fabrication technique for surface-enhanced Raman spectroscopy. Flexible imprint molds with sub-10 nm features were duplicated from AAO templates using a novel hybrid mold technique. This method solves the nonflatness-induced defect issue in the conventional thermal nanoimprint technique, and allows high-quality duplications of nanometer features from rigid nonflat templates. Moreover, with the help of the excellent tunability of the size of nanoholes on AAO templates, we were able to tune the size of Ag nanodots, and consequently to tailor the resonance frequency of the Ag nanodot arrays. Finally, surface-enhanced Raman scattering of Rhodamine-123 on Ag nanodot arrays was measured, and large signal enhancement was observed on the 70 nm Ag nanodots. We numerically simulated the optical properties of those Ag nanodot arrays, and excellent agreement was found with the experimental results.     

高速高饱和单行载流子光探测器的设计与分析

设计了一种In P基的背入射台面结构的单行载流子光探测器.通过在吸收层中采取高斯型掺杂界面及引入合适厚度和掺杂浓度的崖层,使得光探测器同时具备了高速和高饱和电流特性.理论分析表明,在光敏面为14μm2、反向偏压为2 V条件下,该器件的3 d B带宽可达58 GHz,直流饱和电流高达158 m A.在大功率光注入条件下,详细分析了光探测器带宽降低和电流饱和现象,得出能带偏移和电场坍塌是其根本原因的结论.     

ZnS：Mn/SiO2量子点的表面聚乙烯吡咯烷酮修饰及其应用于海水中铅离子检测

制备了二氧化硅壳层修饰的ZnS：Mn量子点,基于聚乙烯吡咯烷酮（PVP）与二氧化硅表面硅羟基的作用,在纳米复合微粒表面进行了PVP的修饰,得到了在海水中荧光性能及胶体稳定性良好的ZnS：Mn/SiO₂/PVP 量子点。在Pb²⁺对所制备纳米微粒具有荧光猝灭效应的基础上,建立了用ZnS：Mn/SiO₂/PVP 量子点作为荧光探针检测海水中微量铅离子的新方法。研究表明,量子点浓度为10^-3 mol/L时,海水中离子浓度在10~100 μmol/L范围内与ZnS：Mn/SiO₂/PVP量子点荧光猝灭强度呈良好的线性关系,相关系数为0.994 6,检出限为8×10^-7 mol/L。     

色散金属光学特性分析通用时域有限差分方法

结合数字信号处理中的半解析递归卷积(SARC)算法,提出一种用于金属光学特性分析的改进半解析递归时域有限差分方法(SARC FDTD)。该方法保持了SARC算法的绝对稳定性和高精度、低内存等优点,又利用梯形近似使FDTD递推公式更加简洁,计算效率进一步提高,对于各种常用金属色散模型,均只需给出模型的极点和对应的系数,即可运用该算法的程序进行计算,具有较好的通用性。最后,通过金属的高阶Lorentz,Drude-Lorentz和Drude-CP三种常用色散模型对算法进行了验证。     

67.9W高功率全光纤白光超连续谱激光器

利用自主研发的全光纤被动锁模激光器以及高功率光纤模场匹配器,将145 W的皮秒脉冲耦合进国产光子晶体光纤,实现了67.9 W的高功率全光纤结构白光超连续谱输出,光谱范围为500~1700nm,10dB光谱宽度大于1000nm(泵浦波长除外)。整个激光器系统的光-光(半导体泵浦源输出激光-超连续谱输出激光)转化效率达到33.8%。