πSynthesis and evaluation of a series of α-hydroxy ethers derived from isopropyl oleate

Several fatty derivatives with bulky moieties were prepared by treatment of epoxidized isopropyl oleate with a number of alcohols in the presence of sulfuric acid catalyst to provide a series of α-hydroxy ethers in good yield. The materials were analyzed for cold flow performance through cloud point and pour point determinations. The most promising α-hydroxy ether produced in this study, with respect to both low temperature behavior and economic criteria, was isopropyl 9(10)-(2-ethylhexoxy) 10(9)-hydroxystearate, which has a cloud point of −23°C and pour point of −24°C.     

Preparation, characterization and mechanical properties of epoxidized soybean oil/clay nanocomposites

New epoxidized soybean oil (ESO)/clay nanocomposites have been prepared with triethylenetetramine (TETA) as a curing agent. The dispersion of the clay layers is investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD and TEM data reveal the intercalated structure of ESO/clay nanocomposites has been developed. The thermogravimetric analysis exhibits that the ESO/clay nanocomposites are thermally stable at temperatures lower than 180 °C, with the maximum weight loss rate after 325 °C. The glass transition temperature, T_g, about 7.5 °C measured by differential scanning calorimetry (DSC) and T_g about 20 °C measured by dynamic mechanical study have been obtained. The difference in the T_g between DSC and dynamic measurements may be caused by different heating rate. The nanocomposites with 5-10 wt% clay content possess storage modulus ranging from 2.0×10⁶ to 2.70×10⁶ Pa at 30 °C. The Young's modulus (E) of these materials varies from 1.20 to 3.64 MPa with clay content ranging from 0 to 10 wt%. The ratio of epoxy (ESO) to hydrogen (amino group of TETA) greatly affects dynamic and tensile mechanical properties. At higher amount of TETA, the nanocomposites exhibit stronger tensile and dynamic properties.     

Preparation and characterization of PVA/OMMT composites

In this study, polyvinyl alcohol/organically modified montmorillonite (HDA/MMT; organoclay) composite was prepared for the intercalation processes. Firstly, the rheological behavior of aqueous montmorillonite dispersions was investigated as a function of solid content. Hexadecylamine (HDA) was added to the montmorillonite dispersion (2%, w/w) in different concentrations in the range of 5 × 10^?4 – 9 × 10^?3 mmol/L. The basal spacing of the organoclay (OMMT) was studied by X‐ray diffraction. The FTIR spectra are obtained from the modified montmorillonite products, which revealed the characteristic absorbencies after treatment with HDA. HDA/MMT/PVA composite, which was produced by the reaction of 1 wt % PVA solution with organoclay complex, is characterized by the rheology, electrokinetic, XRD, FTIR, and SEM techniques. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:2315–2323, 2006     

Antibody purification by concanavalin A affinity chromatography

Concanavalin A (Con A) immobilized poly(2‐hydroxyethyl methacrylate) (PHEMA) beads in a spherical form (100–150 μm in diameter) were used for the affinity chromatography purification of human immunoglobulin G (IgG) from aqueous solutions and human plasma. PHEMA adsorbents were prepared by suspension polymerization. Bioligand Con A was then immobilized by covalent binding onto PHEMA beads. The maximum IgG adsorption on the PHEMA/Con A beads was observed at pH 6.0. The nonspecific IgG adsorption onto the plain PHEMA adsorbents was very low (ca. 0.17 mg/g). Higher adsorption values (up to 54.3 mg/g) were obtained when the PHEMA/Con A beads were used from aqueous solutions. A higher adsorption capacity was observed for human plasma (up to 69.4 mg/g) with a purity of 82.5%. The adsorption capacities of other blood proteins were 2.0 mg/g for fibrinogen and 4.2 mg/g for albumin. The total protein adsorption was determined to be 76.0 mg/g. IgG molecules could be repeatedly adsorbed and desorbed with the PHEMA/Con A beads without noticeable loss in the IgG adsorption capacity. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1202–1208, 2005     

Preparation and characterization of conductive polypyrrole/kaolinite composites

Conductive polypyrrole (PPy)/kaolinite clay composites were prepared by in situ chemical polymerization of pyrrole in the presence of kaolinite using FeCl₃ as oxidant. The PPy content and conductivity of the composites reached 32.8% and 8.3×10^?2 S/cm at HCl concentrations of 1.5 M and 0.5 M, respectively. The microhardness of the composites containing different amounts of PPy was higher than that of the PPy and kaolinite components. The highest microhardness observed was 30.17 kg/mm² for the composite containing 9.6% PPy. The electrical resistance of the composites was monitored during heating–cooling cycles over the range 5–120 °C. The change in resistance with temperature was more repeatable for the composite than for PPy. The composites were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The humidity-sensing properties were also examined.     

Microbial profile and bacterial characterisation of naturally debittered Hurma olives compared to non‐debittered Erkence variety during ripening period

Naturally debittered Hurma olive is grown in a specific area in Karaburun peninsula in Turkey. It is characterised by its sweet taste and it differs from other varieties by losing its bitterness caused by phenolic compounds during its maturation period on the tree. Therefore, Hurma olive does not require any further debittering process to be served as table olive. This study was particularly interested in the comparison of the microbial profile of Hurma olive during its 8 weeks of maturation period in two subsequent harvest years and Erkence (not naturally debittered) olive. In addition, main bacterial profile of both Hurma and Erkence olives were isolated and identified. Aerobic mesophilic microorganism (AMM), lactic acid bacteria (LAB), Enterobacteriaceae, Pseudomonadaceae, Staphylococci, Micrococcaceae, yeasts and moulds (Y&Ms) were detected (counted and isolated) in the olive drupes during the maturation period. Isolated bacteria were identified as different spp. of Bacillaceae, Enterobacteriaceae, Micrococcoceae and Pseudomonadaceae.     

Excitation energy-dependent nature of Raman scattering spectrum in GaInNAs/GaAs quantum well structures

The excitation energy-dependent nature of Raman scattering spectrum, vibration, electronic or both, has been studied using different excitation sources on as-grown and annealed n- and p-type modulation-doped Ga_1 − xIn_xN_yAs_1 − y/GaAs quantum well structures. The samples were grown by molecular beam technique with different N concentrations (y = 0%, 0.9%, 1.2%, 1.7%) at the same In concentration of 32%. Micro-Raman measurements have been carried out using 532 and 758 nm lines of diode lasers, and the 1064 nm line of the Nd-YAG laser has been used for Fourier transform-Raman scattering measurements. Raman scattering measurements with different excitation sources have revealed that the excitation energy is the decisive mechanism on the nature of the Raman scattering spectrum. When the excitation energy is close to the electronic band gap energy of any constituent semiconductor materials in the sample, electronic transition dominates the spectrum, leading to a very broad peak. In the condition that the excitation energy is much higher than the band gap energy, only vibrational modes contribute to the Raman scattering spectrum of the samples. Line shapes of the Raman scattering spectrum with the 785 and 1064 nm lines of lasers have been observed to be very broad peaks, whose absolute peak energy values are in good agreement with the ones obtained from photoluminescence measurements. On the other hand, Raman scattering spectrum with the 532 nm line has exhibited only vibrational modes. As a complementary tool of Raman scattering measurements with the excitation source of 532 nm, which shows weak vibrational transitions, attenuated total reflectance infrared spectroscopy has been also carried out. The results exhibited that the nature of the Raman scattering spectrum is strongly excitation energy-dependent, and with suitable excitation energy, electronic and/or vibrational transitions can be investigated.     

蔚县矿区奥陶系下统灰岩岩溶发育规律的研究

对矿区基底O1灰岩的溶隙、溶孔、溶洞进行综合分析,得出矿区的岩溶形态和岩溶发育程度特征。对研究奥陶系灰岩岩溶含水层的发育分布特征、富水特征及其地下水运移规律具有重要意义。     

电镀制备铟-锡合金电极及其电还原二氧化碳性能

以腐蚀铜网为基体,在硫酸盐镀液中制备得到用于电还原CO2的铟-锡合金电极。对镀液配方进行了筛选,并通过正交试验对镀液配方进行优化,得到制备铟-锡合金电极的最佳工艺条件为:In2(SO4)350g/L,SnSO430g/L,柠檬酸40g/L,添加剂TSNA4g/L,稳定剂3g/L,电流密度1.5A/dm2,温度25°C,pH约1.5。最佳工艺下制备的In-Sn合金镀层呈均匀的灰白色,结合力良好,In-Sn合金电极上电还原CO2生成甲酸的电流效率达71%,稳定性良好。