Surface‐Enhanced Raman Scattering Using Microstructured Optical Fiber Substrates

Microstructured optical fibers (MOFs) represent a promising platform technology for fully integrated next generation surface enhanced Raman scattering (SERS) sensors and plasmonic devices. In this paper we demonstrate silver nanoparticle substrates for SERS detection within MOF templates with exceptional temporal and mechanical stability, using organometallic precursors and a high‐pressure chemical deposition technique. These 3D substrates offer significant benefits over conventional planar detection geometries, with the long electromagnetic interaction lengths of the optical guided fiber modes exciting multiple plasmon resonances along the fiber. The large Raman response detected when analyte molecules are infiltrated within the structures can be directly related to the deposition profile of the nanoparticles within the MOFs via electrical characterization.     

地下工程氡防护方法及能力研究北大核心CSCD

为科学确定地下工程氡防护措施,本文根据地下工程氡防护经验,梳理了典型氡防护方法,并通过实际测量和性能实验,评价各种氡防护方法。结果表明,通风降氡是地下工程降氡普遍方法,对12000 m^(3)空间按照2 m^(3)/s风速通风1小时能够降低空气中氡浓度三分之一左右;吸附降氡能够对人员活动集中区域进行局部降氡,采用自研的移动降氡装置工作2小时能够使80 m^(3)含氡空气的氡浓度降低55%左右;屏蔽降氡能够对高氡析出率区域进行重点降氡,采用聚酰亚胺树脂防氡材料能够使阻氡效率大于99.5%。不同降氡方法都有其适用范围和优缺点,应根据地下工程实际情况进行优化设计。     

离子束电子束多功能材料表面处理设备

本设备由以下系统组成:注入系统,有溅射离子源及不对称三电极加速管,能量50keV,流强4mA(N~+);电子束系统,能量45keV,功率密度10~2—10~6W/ cm~2;配备微机程序的束偏摆装置;靶材易换的磁控溅射靶;可作旋转、平移、升降等机械运动的高真空工作室(φ500×1600mm)。可进行离子注入及混合、电子束上釉及合金化、磁控溅射离子镀等工艺。该设备为材料表面改性和薄膜制备提供了新的手段。     

195keV Ar^＋辐照非晶态合金表面损伤形貌的研究

用扫描电子显微镜观测研究了室温下１９５ｋｅＶＡｒ＋辐照非晶态合金Ｃｏ（６０）Ｆｅ（１２）Ｎｉ（１０）Ｓｉ６Ｂ（１２）和Ｆｅ（３９）Ｎｉ（３９）Ｖ２Ｓｉ（１２）Ｂ８在各剂量阶段的表面损伤形貌。结果表明，表面损伤是发泡和溅射相互竞争的过程。低剂量下，表面损伤以发泡为主；而在高剂量时，表面发泡消失，溅射造成的多孔粗糙表面损伤结构形成。对高剂量时表面发泡消失的可能机制作了探讨。     

高岭土深加工技术研究的进展

较全面地介绍了高岭土的纯化处理、超微粉碎、煅烧和表面改性处理的试验研究和应用情况，为推动高岭土深加工技术的研究和开发提供了有效方法。     

Research progress of solid electrolytes

商业化的锂离子电池大多采用有机液体作为电解质体系,有机液体电解质在电池的工作过程中,会发生泄漏、挥发、燃烧甚至爆炸,存在严重的安全隐患,研究高效、环保、安全的电解质是解决这一问题的主要途径。固体电解质取代传统的液体电解质,不仅可以在传输导锂的同时抑制锂枝晶的生长,而且具有高的机械强度,简化电池的制备工艺,降低电池的制造成本。由于具有以上的优点,固体电解质的研发不断引起人们的广泛关注。本文综述了硫化物固体电解质的研究进展,包括二元和三元硫化物固体电解质,同时讨论了掺杂改性或复合改性对其性能影响,并展望了硫化物固体电解质未来的发展方向。     

PU湿法半成品印刷压花取代干法贴膜

PU湿法半成品的后序加工步骤制PU革过程中,可以采用印刷压花工艺,成品质量和表现效果能够与干法贴膜加工所得的革相当,而且可以降低成本。     

Properties of PVA-AA cross-linked HEMA-based hydrogels

Poly(HEMA) hydrogel is usually prepared by using 1,1,1-trimethylol propane trimethacrylate and ethylene glycol dimethacrylate as the crosslinkers. Another method using PVA-AA (polyvinyl alcohol partially esterified with acryloyl chloride) as the cross linker is reported here. Two hydrogels, co-A1H9 and co-A2H8, were prepared by the polymerization of HEMA in the presence of 10% and 20% PVA-AA, respectively. The presence of PVA-AA reduced the water content from 32% to 25% in the resultant copolymer, whereas T_g did not change significantly. Co-A1H9 had an elastic modulus of 6.3 Mpa, which is much higher than 3.9 MPa and 3.7 MPa for poly(HEMA) and co-A2H8, respectively. The interfacial energies of poly(HEMA), co-A1H9 and co-A2H8 were calculated to be 0.52, 0.65 and 0.71 dyne/cm², respectively, whereas the fractional polarities of these three hydrogels were all about 0.74. Thus a HEMA-based hydrogel with surface properties similar to poly(HEMA) but with stronger mechanical strength was successfully prepared. This copolymeric hydrogel could provide a choice other than the conventionally cross linked poly(HEMA) for various applications.     

A Vycor® Membrane with Reduced Size Surface Pores I. Preparation and Characterization

Vycor® membranes are surface-modified by a crosslinked commercial silicone which is subsequently subjected to oxygen plasma and converted to silica dioxide. Samples are examined by integral gas permeability of helium, nitrogen, methane and carbon dioxide, differential permeability of carbon dioxide and relative permeability of helium gas vs. water vapor. The modified surface is found to contain large micropores as well as a population of small nanopores. The new membrane may be appropriate for applications such as gas/vapor separations, reverse osmosis and the low molecular weight end of nanofiltration.     

Surface area, pore size distribution and microstructure of combustion engine deposits

The structural characteristics of combustion engine deposits produced from fuels with 22–44% aromatics by volume have been studied using Raman spectroscopy and gas sorption techniques. The lateral sizes of graphitic crystallites were found to increase slightly with the aromatic content of the fuel used. The surface areas of the deposits were evaluated using the BET and DR theories. Density functional theory (DFT) and mercury porosimetry were used to evaluate pore size distributions. The deposits have large internal surface areas (in the approximate range 100–300 m²/g) and their structures are highly porous. The average pore sizes of the largely microporous deposits do not depend on the aromatic content of the precursor fuel. Walls of pores with widths of about 0.5 nm are primarily responsible for the majority of the internal surface area found in the deposits. Heat treatment at temperatures above 573 K results in increased surface areas because the release of small hydrocarbon fragments from the deposits opens pores which were not accessible following heat treatment at lower temperatures.