High-quality, oriented and mesostructured organosilica monolith as a potential UV sensor

We synthesized high-quality and oriented periodic mesoporous organosilica (PMO) monoliths through a solvent evaporation process using a wide range of mole ratios of the components: 0.17–0.56 1,2-bis(triethoxysilyl)ethane (BTSE): 0.2 cetyltrimethylammonium chloride (CTACl): 0–1.8 × 10⁻³ HCl: 0–80 EtOH: 5–400 H₂O. X-ray diffraction (XRD) patterns and transmission electron microscopy (TEM) images indicated that the mesoporous channels within the monolith samples were oriented parallel to the flat external surface of the PMO monolith and possessed a hexagonal symmetry lattice (p6mm). The PMO monolith synthesized from a reactant composition of 0.35 BTSE: 0.2 CTACl: 1.8 × 10⁻⁶ HCl: 10 EtOH: 10 H₂O had a pore diameter, pore volume, and surface area – obtained from an N₂ sorption isotherm – of 25.0 Å, 0.96 cm³ g⁻¹ and 1231 m² g⁻¹, respectively. After calcination at 280 °C for 2 h in N₂ flow, the PMO monolith retained monolith-shape and mesostructure. Pore diameter and surface area of the calcined PMO monolith sample were 19.8 Å, 0.53 cm³ g⁻¹ and 1368 m² g⁻¹, respectively. We performed ²⁹Si and ¹³C CP MAS NMR spectroscopy experiments to confirm the presence of Si–C bonding within the framework of the PMO monoliths. We investigated the thermal stability of the PMO monoliths through thermogravimetric analysis (TGA). In addition, rare-earth ions (Eu³⁺, Tb³⁺ and Tm³⁺) were doped into the monoliths. Optical properties of those Eu³⁺, Tb³⁺ and Tm³⁺-doped PMO monoliths were investigated by photoluminescence (PL) spectra to evaluate their potential applicability as UV sensors.     

Time averaged temperature calculations in pulse electrochemical machining, part II: numerical simulation

Simulation of the temperature distribution and evolution during pulse electrochemical machining can be a computationally very expensive procedure. In a previous part of the work [Smets et al. J Appl Electrochem 37(11):1345, 2007] a new approach to calculate the temperature evolution was introduced: the hybrid method, which combines averaged and pulsed calculations. The averaged calculations are performed by time averaging the boundary conditions and the bulk heat sources of the system. The timesteps used during the averaged calculations are then no longer dictated by the pulse characteristics. Using this approach, computationally very cheap, yet satisfactory results can be obtained. The analysis in the previous part of the work was obtained from analytical solutions on simplified models. In this part, the more general case is solved numerically. Multiple geometries are simulated and analyzed and methods are compared. Very satisfactory, yet cheap results are obtained.     

微波消解ICP-MS法对食品中铝含量的测定分析

对市售的膨化食品、鲜、干水产品、豆制品采用微波仪消解,在电感耦合等离子体质谱仪上采用钪(Sc)作为内标元素对其中铝含量进行直接定量分析.方法前处理简便,测量快速、灵敏、准确.方法检出限为0.3 mg/kg ,相对标准偏差＜3 % ,加标回收率在85 %～104 %.     

预涂金属卷材用水性环氧聚酯底漆的研制

将水性环氧树脂、丙烯酸改性饱和聚酯树脂、氨基树脂、插层改性累托石、各种颜填料和助剂按比例制成预涂金属卷材用水性环氧聚酯底漆。讨论了不同颜基比以及不同用量的环氧树脂、颜填料、插层改性累托石和偶联剂对漆膜性能的影响。获得了水性环氧聚酯底漆最佳配方:环氧树脂用量占树脂总固体分的15%,锶铬黄和插层改性累托石的用量分别占颜填料用量的30%和2%~3%,硅烷偶联剂1%。所得漆膜的附着力0级,硬度2H,T弯0,耐MEK擦试70次,抗流挂性和流平性良好。     

氨水沉淀-水热处理制备阻燃型氢氧化镁

以卤水、卤块和六水氯化镁为原料,采用两步法即氨水沉淀-水热处理过程制备出氢氧化镁阻燃剂.比较分析了水热处理、矿化剂、杂质硫酸根离子等因素对制备阻燃型氢氧化镁的作用及影响.实验结果表明:氨水沉淀得到的中间体经过水热处理,晶体的生长方向发生改变,(101)极性面得到抑制,而(001)面显露较多,特征衍射峰强I(001)/I(101)增大.杂质硫酸根对制备阻燃型氢氧化镁具有很大的影响,除去大部分硫酸根有利于制备结构稳定的氢氧化镁阻燃剂.两步法制备的阻燃型氢氧化镁产品为六方片状,较薄,分散性好,平均粒径200 nm.产品纯度高(98.92%～99.06%),产品质量符合中国行业标准;而且两步法具有原料来源广、生产成本低、适宜工业化生产等特点.     

Synthesis and in vitro evaluation of alpha-GalCer epimers

alpha-GalCer (also known as KRN7000) is an immunomodulatory glycolipid that is known to potently activate invariant natural killer T (NKT) cells upon CD1d-mediated stimulation. Because Th1 and Th2 cytokines, which are released after alpha-GalCer presentation, antagonize each other's effects, alpha-GalCer analogues that induce a biased Th1/Th2 response are highly awaited. In this context, we report the synthesis and in vitro evaluation of alpha-Gal-D-xylo-Cer and two alpha-Gal-L-lyxo-Cer analogues, one with the natural acyl chain, the other with a truncated chain.     

Continuous operation of membrane bioreactor treating toluene vapors by Burkholderia vietnamiensis G4

A laboratory-scale biofilm membrane bioreactor inoculated with Burkholderia vietnamiensis G4 was examined to treat toluene vapors in a waste gas stream. The gas feed side and nutrient solution were separated by a composite membrane consisting of a porous polyacrylonitrile (PAN) support layer coated with a very thin (0.3 μm) dense polydimethylsiloxane (PDMS) top layer. After inoculation, a biofilm developed on the dense layer. The biofilm membrane bioreactor was operated continuously at different residence times (28–2 s) and loading rates (1.2–26.7 kg m⁻³ d⁻¹), with inlet toluene concentrations ranging from 0.21 to 4.1 g m⁻³. The overall performance of the membrane bioreactor was evaluated over a period of 165 days. Removal efficiencies ranging from 78% to 99% and elimination capacities from 4.2 to 14.4 kg m⁻³ d⁻¹ were observed after start-up period depending on the mode of operation. A maximum elimination capacity of 14.4 kg m⁻³ d⁻¹ was observed at a loading rate of 17.4 kg m⁻³ d⁻¹. Overall, the results illustrate that biofilm membrane reactors can potentially be more effective than conventional biofilters and biotrickling filters for the treatment of air pollutants such as toluene.     

Review on morphology development of immiscible blends in confined shear flow

The bulk dynamics of immiscible polymer blends during flow is relatively well understood, especially when the system contains Newtonian components. Recently, a number of studies have focused on flow of immiscible blends in confined geometries. In that case, the morphology development is not only affected by the material characteristics and the type of flow, but also by the degree of confinement. Here, we present an overview on the morphology development in immiscible two-phase blends in confined shear flow. Firstly, we focus on the typical microstructures that are observed in confined dilute blends. Secondly, in order to understand those peculiar morphologies, the systematic studies on single droplets in confined shear flow are reviewed. In addition to the experimental work, theoretical, phenomenological, and numerical models that include the effects of confinement are discussed.     

电压降法在水平定向钻穿越管道外涂层评价中的应用研究

介绍了电流-电位法、电流密度法在水平定向钻穿越管道外涂层评价中的应用,联合电压降法计算管内电流值,并结合实际案例对穿越管道两端连头之后外涂层性能进行评价.     

液相合成法制备超微粒羟基磷灰石的研究

羟基磷灰石是人体和动物骨骼的主要无机成分,具有良好的生物活性和生物相容性,是极其重要的生物医学材料。介绍了液相合成法制备超微粒羟基磷灰石的研究动态,包括化学沉淀法、水热反应法、溶胶凝胶法、微乳液法,以及现代新技术在液相合成法制备超微粒羟基磷灰石中的应用研究。指出多种方法的交叉合理运用是制备超微粒羟基磷灰石发展的方向。