氟化钠对镁合金表面磷化膜耐蚀性的影响

磷化液中添加氟化钠可改善磷化膜质量,目前对此研究还不系统。分别用添加氟化钠和未添加氟化钠的磷酸二氢铵-高锰酸钾磷化液在AM60镁合金表面制备磷化膜,采用扫描电镜(SEM)、能谱仪和电化学测试对2种磷化膜的表面形貌、成分和耐蚀性进行评价。结果表明:磷化膜可以完整覆盖基体表面,有效地将镁合金与腐蚀介质隔离,提高了镁合金的耐蚀性;添加了氟化钠的磷化膜致密性更好,对镁合金耐蚀性的提高效果更为显著。     

静电纺丝法制备尼龙-6/SiO2-TiO2杂化纳米纤维

采用静电纺丝法结合溶胶凝胶技术,制备了尼龙-6/SiO2-TiO2杂化纳米纤维。采用红外光谱（FT-IR）、X射线衍射（XRD）、UV-vis、热重分析（TG）和扫描电镜（SEM）等对杂化纳米纤维进行分析表征。结果表明,随着SiO2-TiO2溶胶的引入,电纺纤维的结晶度下降,耐热性能提升。尼龙-6电纺纤维的平均直径约为...     

Quantitative Analysis of the Degradation Behavior of Silicon Solar Cell Irradiated by 1 MeV Electron Beams Using Photocarrier Radiometry Combined with Lock-in Carrierography

Silicon solar cells with cover glass irradiated by 1 MeV electron beams at various fluences were investigated using photocarrier radiometry (PCR) combined with lock-in carrierography (LIC, spectrally gated dynamic photoluminescence). The minority carrier transport properties (i.e., minority carrier lifetime τ, diffusion coefficient D, surface recombination velocities S) and the degradation of these properties were studied using PCR. The relative damage coefficient obtained by LIC was consistent with the PCR measurement. The local series resistance of the solar cell before and after irradiation was characterized by LIC. The results showed that the series resistance increased with electron fluences.     

On‐Chip Spiral Waveguides for Ultrasensitive and Rapid Detection of Nanoscale Objects

Ultrasensitive and rapid detection of nano‐objects is crucial in both fundamental studies and practical applications. Optical sensors using evanescent fields in microcavities, plasmonic resonators, and nanofibers allow label‐free detection down to single molecules, but practical applications are severely hindered by long response time and device reproducibility. Here, an on‐chip dense waveguide sensor to monitor single unlabeled nanoparticles in a strong optical evanescent field is demonstrated. The spiral nanowaveguide design enables two orders of magnitude enhancement in sensing area compared to a straight waveguide, significantly improving the particle capture ability and shortening the target analysis time. In addition, the measurement noise is suppressed to a level of 10^?4 in the transmitted power, pushing the detection limit of single particles down to the size of 100 nm. The waveguide sensor on the silicon‐on‐isolator platform can be fabricated reproducibly by the conventional semiconductor processing and compatible with surface functionalization chemistries and microfluidics, which could lead to widespread use for sensing in environmental monitoring and human health.     

Effect of V doping concentration on the electronic structure,optical and photocatalytic properties of nano-sized V-doped anatase TiO2

V-doped TiO₂ with V/Ti ratio of 1–5% has been synthesized by hydrothermal method and then characterized by XRD, TEM, BET specific surface area, XPS and UV–vis. absorption spectra. The photocatalytic activity of the as-synthesized samples was investigated by the degradation of methylene blue in aqueous solution under visible light irradiation. Density functional theory (DFT) based calculations were performed to investigate the mechanism of band gap narrowing, the shift of light absorption edge, the location of V in the TiO₂ lattice and the variation in electronic and optical properties of TiO₂ with the increase of V doping concentration. Irrespective of the V doping concentration, TEM images indicate that all the doped samples were composed of equiaxed spherical anatase TiO₂ particles with good crystallinity and uniform particle size distribution. Both the experimental results from XPS survey and the theoretical calculation argue that the doped V replaces the lattice Ti and form substitutional impurity. The visible light absorption can be optimized by adjusting the V doping concentration. Among the doped samples with different V doping concentrations, the sample with V/Ti ratio of 2% depicts better visible light photocatalytic activity due to the enhanced visible light absorption and improved separation of electron–hole pairs.     

青岛和大连海区海带(Laminaria japonica)外生细菌的16S rRNA基因序列分析

从采集自青岛和大连的大型褐藻海带(Laminaria japonica)表面分离到22株革兰氏阴性海洋细菌。根据16SrRNA基因序列分析结果,将其分别鉴定为假交替单胞菌(Pseudoalteromonas,Cobetia)菌,嗜冷单胞菌(Psychromonas),交替单胞菌(Alteromonas),产碱杆菌(Alcaligens)和海杆菌(Marinobacter)。其中假交替单胞菌在两地样品中占据绝对优势,但每个产地的假交替单胞菌不能单独聚类在一起,不同海区的海带表面存在遗传关系非常接近的菌株。假交替单胞菌之外的其他菌株于两地样品之间存在种或属水平上的差异。本文结果提示外生细菌的种类既与环境相关,又受宿主的状况影响。对8株受试菌株的拮抗实验结果显示了外生细菌在寻找新型抗生素方面的潜力。     

T300碳纤维热处理对Cf/SiC复合材料性能的影响

以聚碳硅烷先驱体浸渍裂解工艺制备T300碳纤维增强3D Cf/SiC复合材料,研究了T300碳纤维预先热处理对材料性能的影响.结果表明,热处理能够弱化Cf/SiC复合材料中纤维-基体界面结合,减少碳纤维在复合过程的损伤,显著提高复合材料性能.纤维经热处理后制备的Cf/SiC复合材料弯曲强度和断裂韧性分别从未经处理的154MPa,4.8MPa·m1/2提高到437MPa,20.4 MPa·m1/2.     

新型海洋趋磁细菌YSC-1的分离及其特异性磁性纳米材料磁小体的研究

从黄海冷水团附近海域的底泥中分离到一株好氧趋磁细菌YSC-1。尽管在淡水中曾经分离过好氧趋磁细菌AMB-1和HM-1,但却从未在海洋中分离到好氧趋磁细菌,因此YSC-1是目前所见报道的第一株海洋好氧趋磁细菌。透射电镜观察表明每个细胞内含1至多个磁小体,呈圆形,直径100nm左右,能谱分析显示该菌磁小体的元素组成为铁(Fe)和(Co)。本文还对该菌的生物学特性进行了初步研究。     

Nanoparticle-induced exosomes target antigen-presenting cells to initiate Th1-type immune activation

The mechanisms associated with the induction of systemic immune responses by nanoparticles are not fully understood, but their elucidation is critical to address safety issues associated with the broader medical application of nanotechnology. In this study, a key role of nanoparticle-induced exosomes (extracellularly secreted membrane vesicles) as signaling mediators in the induction of T helper cell type 1 (Th1) immune activation is demonstrated. In vivo exposure to magnetic iron oxide nanoparticles (MIONs) results in significant exosome generation in the alveolar region of Balb/c mice. These act as a source of nanoparticle-induced, membrane-bound antigen/signaling cargo, which transfer their components to antigen-presenting cells (APCs) in the reticuloendothelial system. Through exosome-initiated signals, immature dendritic cells (iDCs) undergo maturation and differentiation to the DC1 subtype, while macrophages go through classical activation and differentiation to the M1 subtype. Simultaneously, iDCs and macrophages release various Th1 cytokines (including interleukin-12 and tumor necrosis factor α) driving T-cell activation and differentiation. Activated APCs (especially DC1 and M1 subtypes) consequently prime T-cell differentiation towards a Th1 subtype, thereby resulting in an orchestrated Th1-type immune response. Th1-polarized immune activation is associated with delayed-type hypersensitivity, which might underlie the long-term inflammatory effects frequently associated with nanoparticle exposure. These studies suggest that nanoparticle-induced exosomes provoke the immune activation and inflammatory responses that can accompany nanoparticle exposure.     

活塞式半封闭制冷压缩机替代制冷剂的研究

通过对某公司生产的半封闭活塞式制冷压缩机分别应用R404A与R22在中、低温工况下的对比实验研究,来分析使用环保型制冷剂R404A替换R22的可行性,为实际使用提供数据。