Heat-Induced Formation of Monodisperse Gold Nanoparticles in Different Conditions

We investigate the preparation of nearly monodisperse gold nanoparticles by heat treatment in different conditions. The effects of various solvents, heating temperature, and heating time length on the monodispersity of gold nanoparticles were studied systematically and a general route to generate gold nanoparticles with uniform size was determined. The first step was to prepare gold nanoparticles with less than 3 nm and the following operation was to heat the gold nanoparticles in the present of thiolated solvents where monodispersed gold nanoparticles could be obtained easily. Our approach has enriched synthesis of monodisperse gold nanoparticles, and may provide some valuable experimental data about how the heating process affects the size evolution of gold nanoparticles.     

Effect of the Spherical Silica Surface on the Photoluminescence of the Loaded CdS Nanoparticles

CdS nanoparticles were formed on the surface of silica microspheres by the improved layer‐by‐layer self‐assembled technique. High‐resolution electron microscope (HRTEM) image and energy dispersive x‐ray analysis (EDX) confirmed formation of a quasi‐continuous CdS nanoparticles film on the silica microspheres. The results of UV‐vis and fluorescence spectra display that the spherical silica surface has a great effect on the photoluminescence of the loaded CdS nanoparticles. In contrast to the CdS nanoparticles powder, the composite can exhibit the emission ascribed to the band gap transition when the CdS nanoparticles film is relatively thick. This phenomenon is probably due to an enhancement of the crystallinity of CdS nanoparticles induced by the silica spheres.     

Surface-Modified Sb2S3 Nanoparticles and Their Tribological Behaviors in Liquid Paraffin

Sb₂S₃ nanoparticles surface-modified with S-tetradecyl N, N-dihydroxyethyl dithiocarbamate (C₁₄DTC-Sb₂S₃) have been synthesized via extraction of Sb₂S₃ colloidal particles from ethylene glycol into toluene in the presence of C₁₄DTC. The obtained products were characterized by high-resolution transmission electron microscope (HRTEM) and Fourier transformation infrared (FTIR), and their tribological behaviors as an additive in liquid paraffin were investigated using a four-ball tribometer. The results show that C₁₄DTC-Sb₂S₃ nanoparticles can significantly improve the friction reduction, anti-wear, and load-carrying properties of base oils. The preliminary lubrication mechanism was discussed based on the SEM and XPS investigation of the rubbed surfaces.     

Fabrication and characterization of an irradiation facility for large-sample geometry

An irradiation facility consisting of a modified beam port shielding plug has been designed, fabricated built and characterized for use in irradiating non-standard sample geometries. The shielding plug features a graphite moderator at the core end with a hole, or “well” drilled of sufficient diameter and depth to accommodate an eight ounce (227 gram) sample bottle. Added shielding behind the graphite consists of castable neutron- and -gamma-ray shielding. The modified shielding plug can be removed relatively quickly from its irradiation position to minimize personnel exposures. It is mounted in close proximity to the Ohio State University Research Reactor reactor core to allow performance of high-sensitivity neutron activation analysis studies. Using the SAND-II unfolding code, the energy-dependent neutron flux has been measured in the sample irradiation position. When operating at 100 % power, the total flux is 3.9 × 10¹² n/cm²/s. Of this, 55 % is thermal (<0.5 eV), 23 % is epithermal (>0.5 eV, <0.5 MeV), and 22 % is “fast” (>0.5 MeV). This makes the facility suitable for neutron activation studies. Recently it has been used for irradiation of filter papers collected in a study of particulate air pollution in the form of atmospheric particulate matter in an urban environment.     

纳米金标记抗体增强SPR检测大肠杆菌O157∶H7

将金纳米粒子(AuNPs)标记的大肠杆菌O157∶H7(E.coli O157∶H7)的多克隆抗体(PAb)作为二抗,采用氨基偶联法将PAb固定在传感器表面作为一抗,通过三明治方法用双通道表面等离子体子共振(SPR)传感器对E.coli O157∶H7进行检测,并与SPR直接法检测进行了比较.结果表明,直接法的检出限为103cfu/mL,线性范围为103～109cfu/mL;AuNPs增强三明治法的检出限为10 cfu/mL,线性范围为10～1010cfu/mL,灵敏度比直接法提高了100倍,且具有更宽的检测范围.本方法不仅检测时间短,而且具有良好的选择性和重现性.     

奎宁-杂多酸杂化催化剂催化H2O2为氧源的苯羟基化反应

将奎宁与Keggin结构磷钼钒杂多酸结合制备出一种新颖的多相苯羟基化杂化催化剂, 采用傅里叶变换红外光谱、紫外-可见光谱、X射线衍射、扫描电镜、热重、N₂吸附-脱附和CHN元素分析等表征手段对催化剂进行了分析. 结果表明, 该催化剂是一种具有较高比表面积和孔体积的半无定形有机杂多酸盐. 在H₂O₂为氧源的苯羟基化反应中, 杂化催化剂引导了液-固两相催化体系, 表现出较高催化活性和重复使用稳定性. 催化剂中奎宁与杂多阴离子间的氢键和电子相互作用赋予了其高熔点和难溶性, 而高比表面积和因奎宁而改善的杂多阴离子的氧化还原性是其获得优异催化性能的主要原因. 这为多相苯羟基化反应提供了一种新的且制备便捷的基于多金属氧酸盐的高效催化剂.     

Synthesis and characterization of biodegradable polyesteramides constructed mainly by alternating diesterdiamide units from N,N′-bis(2-hydroxyethyl)-adipamide and diacids

Two kinds of aliphatic alternating polyesteramide prepolymers were prepared through melt polycondensation from N,N’-bis(2-hydroxyethyl)-adipamide and adipic acid or sebacic acid. Chain extension of them was conducted with 2,2′-(1,4-phenylene)-bis(2-oxazoline) and adipoyl biscaprolactamate as combined chain extenders. The chain extended polyesteramides (ExtPEAs) were characterized by IR, 1 H-NMR, differential scanning calorimetry, thermogravimetric analysis, wide angle X-ray scattering, tensile test and enzymatic degradation. The results showed that the ExtPEA(4,m)s were mainly constituted with the diester adipamide alternating units. ExtPEA(4,4) and ExtPEA(4,8) had Tm of 83.8℃ and 85.8℃ and initial decomposition temperature above 310.0℃. They crystallized similarly as Nylon-66 did and were flexible thermoplastic materials with tensile strength up to 25.64 MPa and strain at break up to 737%.     

Solution-processed bilayer photovoltaic devices with nematic liquid crystals

The cross-linking of polymerisable liquid crystalline semiconductors is a promising approach to solution-processable, multilayer, organic photovoltaics. Here we demonstrate an organic bilayer photovoltaic with an insoluble electron-donating layer formed by cross-linking a nematic reactive mesogen. We investigate a range of perylene diimide (PDI) materials, some of which are liquid crystalline, as the overlying electron acceptor layer. We find that carrier mobility of the acceptor materials is enhanced by liquid crystallinity and that mobility limits the performance of photovoltaic devices.     

Facile synthesis of gemini surface-active ATRP initiator and its use in soap-free AGET ATRP mini-emulsion polymerisation

A novel cationic gemini surfactant has been readily synthesised in 70 % total yield. The functional gemini surfactant can act both as an emulsifier and an atom transfer radical polymerisation (ATRP) initiator in mini-emulsion polymerisation of methyl methacrylate (MMA), in which no other emulsifier was required. 1-(Dimethylamino)dodecane (N,N-dimethyldodecylamine, DMDA) was found to be a good ligand in the activator generated by electron transfer (AGET) ATRP reaction. Kinetic studies indicated that the polymerisation featured controlled/living radical polymerisation.     

羟基磷灰石及其复合材料对重金属的吸附研究进展

羟基磷灰石具有特殊的晶体结构,对二价的重金属离子有很强的结合力,是一种可用于环境污染治理的新型功能性材料。它可有效地吸附去除水中的Pb2+,Cd2+,Cu2+,Zn2+,Co2+,Ni2+等重金属离子,但其粉体的结构却限制了它在水环境中的实际应用。随着纳米技术、复合材料技术的发展,在羟基磷灰石的基础上开发出的具有高效吸附性能或分离特性的新型材料在重金属吸附研究中显示了潜在的优势。本文综述了羟基磷灰石及其复合材料对水中重金属去除方面的研究进展,探讨了它对重金属吸附机理,并对羟基磷灰石进一步的研究提出了展望。