阴离子表面活性剂存在下光系统Ⅱ中酪氨酸残基的性能研究

通过荧光光谱和富立叶变换红外 (FT IR)光谱研究了阴离子型表面活性剂 -十二烷基硫酸钠 (SDS)与光系统Ⅱ (PSⅡ )的相互作用 .结果表明 ,PSⅡ表现出酪氨酸荧光的特性 .在PSⅡ蛋白质内部 ,存在着 2 32nm处的组分与酪氨酸之间以及这两种氨基酸残基与叶绿素a之间的能量传递 .SDS的存在会使这些能量传递以及PSⅡ中蛋白的骨架结构和酪氨酸残基的结构发生改变 ,而变化方式又明显受SDS在溶液中聚集状态的影响 .低于其临界胶束浓度(cmc)时 ,SDS会促进蛋白质中 2 32nm处的组分与酪氨酸之间的能量传递 ,并且使酪氨酸残基处于极性更小的环境 ;而大于cmc时 ,SDS却产生相反的效应 .但不同浓度的SDS均会抑制酪氨酸残基至叶绿素a的能量传递 .

直接苷化法合成烷基糖苷的研究

本文以月桂醇、葡萄糖为原料，采用复合催化剂利用直接苷化法合成了十二烷基葡萄糖苷，探讨了其各主要影响因素，得出适宜的反应条件为：反应压力为４．０５ｋＰａ；反应温度为１２０℃；醇糖比为５：１；剂糖比为０．００８：１。

Effect of surfactants on dispersion property and morphology of nano-sized nickel powders

Fine face-centered cubic (FCC) nickel powders were synthesized by liquid phase reduction with different surfactants. The products were investigated by scanning electron microscopy (SEM), laser particle size analyzer and X-ray powder diffraction (XRD). The results indicate that the type, dosage and relative molecular mass of surfactants significantly impact the purity, dispersion property, particle size, size distribution and morphology of the products. The nonionic surfactants poly ethylene glycol (PEG) and polyethylene glycol sorbitan monostearate (Tween) showed better dispersing ability in the reaction system than the others. The optimal mass ratios of surfactant to Ni are 100 mg/g and 150 mg/g for PEG-600 and Tween-40, respectively. The products obtained in the optimal conditions have ideal morphology and narrow size distribution. Moreover, study on the relative molecular mass effect revealed that with the increase of the relative molecular mass of Tween, the morphology of nickel powders changed from sphere to spiny ball.

Synthesis and Surface Activity of Heterogemini Imidazolium Surfactants

A series of heterogemini imidazolium surfactants with two-methylene spacer groups （[Cm- 2-Cnim]Br2, m, n=8, 10, 12, 14, 16; m≠n） have been synthesized and characterized by 1H NMR and ESI-MS spectroscopy. The effects of various reaction parameters, including stoichiometry, reaction temperature and time, were investigated. In addition, the surface activity study about heterogemini imidazolium surfactants was carried out and the influences of dissymmetric degree on the surface properties were also discussed.

Solvothermal Synthesis of V_2O_3 Catalysts for Oxidative Desulfurization of Dibenzothiophene

V2O3 nanoparticles with high surface area have been successfully prepared by a new solvothermal method without using any surfactant and template. The size of V2O3 nanoparticles is mostly equal to 10 nm-30 nm. The highest surface area of obtained V2O3 nanoparticles reaches 49 m2/g. Several kinds of V2O3 catalysts were prepared by different methods. All these V2O3 catalysts obtained thereby showed high catalytic activity for oxidative desulfurization(ODS) reaction by using tert-butyl hydroperoxide as the oxidant. The V2O3 catalyst with a highest ODS activity was obtained under the following conditions: The catalyst was prepared upon using V2O5 as the vanadium source, methanol as the solvent, and oxalic acid as the complexing reagent at a V2O5/oxalic acid molar ratio of 1:2. The process for ODS of dibenzothiophene was carried out under mild conditions(under atmospheric pressure and at a relatively low temperature). The highest ODS activity of the obtained V2O3 nanoparticles can be attributed to their highest surface area.

Effects of activating flux on CO_2 laser welding process of 6013 Al alloy

In order to increase the absorption of laser energy and improve the weld appearance in laser welding of Al alloy, 1.8 mm- 6013 Al alloy plate was welded by activating flux CO2 laser welding. Activating flux includes oxide and fluoride, which was coated on the workpiece surface before welding. The experimental results show that the activating flux can effectively improve the absorption of CO2 laser energy and increase the amount of the molten base metal. The improvement on the absorption of laser energy by oxide activating flux is greater than that by fluoride activating flux or two-component activating flux, but the slag detachability made from both the single activating flux and two-activating flux is poor. The gas pore sensitivity with oxide activating flux is much higher than that with fluoride activating flux in CO2 laser welding of 6013 Al alloy.

The Dependence of the Dissociation Rate of Methane-SDS Hydrate below Ice Point on Its Manners of Forming and Processing

The dissociation rates of methane hydrates formed with and without the presence of sodium dodecyl sulfate （methane-SDS hydrates）, were measured under atmospheric pressure and temperatures below ice point to investigate the influence of the hydrate production conditions and manners upon its dissociation kinetic behavior. The experimental results demonstrated that the dissociation rate of methane hydrate below ice point is strongly dependent on the manners of hydrate formation and processing. The dissociation rate of hydrate formed quiescently was lower than that of hydrate formed with stirring; the dissociation rate of hydrate formed at lower pressure was higher than that of hydrate formed at higher oressure; the comoaction of hydrate after its formation lowered its stability, i.e., increased＇its dissociation rate.The stability of hydrate could beincreased by prolonging the time period for which hydrate was held at formation temperature and pressure before it was cooled down, or by prolonging the time period for which hydrate was held at dissociation temperature and formation pressure before it was depressurized to atmospheric pressure. It was found that the dissociation rate of methane hydrate varied with the temperature （ranging from 245.2 to 272.2 K） anomalously as reported on the dissociation of methane hydrate without the presence of surfactant as kinetic promoter. The dissociation rate at 268 K was found to be the lowest when the manners and conditions at which hydrates were formed and processed were fixed.

Research on the effect of the component proportion in the new water mist additive on firefighting performance

Water mist technology provides efficient firefighting performance while there is still room for improvement. So varieties of additives have been studied in recent years both at home and abroad. The self-made additives are used to compare the firefighting performance of diesel and heptane fire in open space. By adjusting the concentration of substance in the additives and conducting the experiment under the pressure of 0.3 MPa,0.5 MPa and 0.7 MPa,extinguish time and temperature are measured in the experiment. Through the experiments using different fuels,it can be found when the fuel is heptane that has a lower ignition point and a higher evaporation rate, the water mist additive can still significantly improve the firefighting performance. According to the data based on different concentrations of fluorinated surfactants,we find that fluorinated surfactants are the main substance to improve the performances by changing physical property of water mist. Optimal proportion of the additives for firefighting performance is found by experiment results.

High Temperature Seedless Synthesis of Au NRs Using BDAC/CTAB Co-surfactant

Au nanorods have been successfully synthesized at 90 ℃ by using hexadecyltrimethylammonium bromide （CTAB） and benzyldimethylammoniumchloride hydrate （BDAC） co-surfactant. At 90 ℃, the reaction time was less than 10 s, and the longitudinal surface plasmon absorption band could vary between 680 and 770 nm by adjusting the molar ratio of BDAC to CTAB from 2 to 0.5. At 90 ℃, nanorods with a longitudinal surface plasmon absorption peak of 770 nm can be obtained when the molar ratio of BDAC to CTAB was 3：2.

Synthesis of Silver Nanoparticle and Its Morphological Control

Silver nanoparticles with different morphologies were prepared in AgNO3 aqueous solution using nanocarbon as template medium and polymer surfactant as protecting agent in an ultrasonic field.The polymer surfactant polyvinylpyrrolidone(PVP)was self-prepared and used directly in aqueous solution form.The molecular weight of PVP was measured by viscosimeter.The crystalline phase,component,size,and morphology of the as-synthesized silver naoparticles were characterized by XRD,TEM,FTIR,and Laser Granularity Instrument.The results indicated that ultrasonic was the key factor to deoxidize Ag+ to be Ago,nanocarbon and polymer surfactants accelerated the deoxidization reaction course and controlled the agglomeration of freshly formed silver nanoparticles,the category of polymer surfactant had decisive effect on the morphology of as-synthesized nanoparticle.Well-defined dendrites silver nanoparticle could be attained when choosing PVP as surfactant in AgNO3 aqueous solution,while regular sphere silver nanoparticle could be synthesized in the presence of polyvinyl alcohol(PVA)surfactant.Moreover,the concentration of AgNO3 and ultrasonic action time also had obvious effect on the morphology of silver nanoparticle,low concentration of AgNO3 and long time of ultrasonic were not in favor of forming dendrite silver.

Experimental Study of Natural Gas Storage in Hydrates

Hydrate formation rate plays an important role in the making of hydrates for natural gas storage. The effect of sodium dodecyl sulfate (SDS), alkyl polysaccharide glycoside (APG) and cyclopentane (CP) on natural gas hydrate formation rate, induction time and storage capacity was studied. Micellar surfactant solutions were found to increase hydrate formation rate in a quiescent system and improve hydrate formation rate and natural gas storage capacity. The process of hydrate formation includes two stages with surfactant presence. Hydrate forms quickly in the first stage, and then the formation rate is slowed down. Surfactants (SDS or APG) reduce the induction time of hydrate formation. The effect of an anionic surfactant (SDS) on gas storage in hydrates is more pronounced compared to a nonionic surfactant (APG). CP also reduces the induction time of hydrate formation, but can not improve the natural gas storage capacity in hydrates.

Synthesis of texture-excellent mesoporous alumina using PEG1000 as structure-directing agent

By varying concentration of PEG1000 as a structure-directing agent,mesoporous alumina with excellent textural properties was synthesized.The prepared mesoporous alumina displays high thermal stability,as shown by its textural properties at different calcination temperatures of 600-850 °C.Characterization by SEM and TEM revealed that the added PEG surfactant induced the formation of petal-like alumina.XRD results clarified that all samples were amorphous and their peaks were around the peaks of γ-alumina.N_2 adsorption-desorption analysis showed that the prepared mesoporous alumina,if with PEG1000 in hydrolysis of aluminum isopropoxide,had excellent textural properties with large specific surface area,high pore volume and suitable pore size.The petal-like structure existing in the alumina samples improved their textural parameters,and the role and influential mechanism of PEG1000 were analyzed.

Physicochemical Parameters for Biological and Synthetic Surfactants Used as Detergents

Biological and synthetic surfactants were compared in terms of their ability to reduce interfacial tension, change the thermodynamic characteristics of a pre-conditioned surface, and to modify the rheological properties of their respective formulations at two different temperatures. Both classes of suffactants were able to reduce the inteffacial tension of their formulations to a similar level. However, the biosurfactants were more effective than the synthetics surfactants. Biosurfactants also altered the surface properties of stainless steel, rendering it hydrophilic. Microbial adhesion to stainless steel conditioned with biosurfactants was found to be thermodynamically unfavorable for all microbial strains tested. A linear relationship between shear stress and shear rate was obtained across a range of experimental conditions for all surfactant mixtures, indicating that all formulations behaved as Newtonian fluids.

Synthesis of Nano-ZSM-5 in Ultra-Concentrated System and Its Performance in Diesel Hydrodewaxing

Nanocrystalline ZSM-5(with a crystal size in the range of 20—30 nm) has been synthesized in only 20 h via the crystallization of ultra-concentrated homogeneous synthesis mixtures. The influence of low water content, use of compound surfactant, a proper crystallization time and SiO_2/Al_2O_3 molar ratio on the properties of the final nanocrystalline ZSM-5 has been studied. Especially, the use of compound surfactant has influenced some properties of nano-ZSM such as the morphology, crystal size and crystallization greatly. The nano-ZSM-5 zeolite was investigated using XRD, BET, SEM, NH_3-TPD, and other techniques. The evaluation results in a 200-mL hydrogenation unit indicated that the synthesized nano-ZSM-5 had excellent catalytic performance in diesel hydrodewaxing.

Experiment on Gas Hydrates Formation by Water Spraying

An experimental investigation of natural gas hydrate formation has been conducted in a high-pressure water spraying reactor,which is cooled by the circulation water through an external cooling jacket.The results show that the morphology of hydrates formed by water spraying is like ice-slurry,which depends on the initial pressure and temperature.At a certain reaction pressure,the rate of hydrate formation is increasing with lower temperature.And also,the induction time of hydrate formation can be greatly shortened by water spraying compared to a quiescent system.Solution with appropriate surfactant sodium dodecyl sulfate (SDS) is found to improve the formation rate obviously.

Hydrothermal Synthesis and Mechanism for Formation of Novel Micro-Micro-Mesoporous Aluminosilicate Composite Zeolite

A novel micro-micro-mesoporous aluminosilicate LS-BFMZ （low-silica-BEA（beta）-faujasite （Y）-mesoporous） composite zeolite with the MCM-41 type structure was synthesized through a novel process involving the self- assembly of CTAB surfactant micellae with silica-alumina source originated from alkaline treatment of the beta zeolite. The physical properties of the LS-BFMZ composite zeolite were characterized using various techniques, including XRD, IR and SEM techniques. Meanwhile, a possible mechanism regarding the formation of the LS-BFMZ composite zeolite was proposed.

Surfactant-assisted synthesis and magnetic properties of monodispersed manganese ferrite nanocrystals

Monodispersed manganese ferrite （MnFe2O4） nanocrystals could be successfully synthesized in large quantities via a facile synthetic technique based on the pyrolysis of organometallic compound precursor, in which octadecene was used as solvent, and oleic acid and oleylamine were used as capping ligands. MnFe204 nanocrystals were obtained with size in a tunable range of 4- 15 nm and their morphologies could be tuned from spherical to triangle-shaped by varying the surfactants. The phase structure, morphology, and size of the products were characterized in detail by X-ray diffraction （XRD） and transmission electron microscopy （TEM）. Magnetic properties of MnFe2O4 nanocrystals with different morphologies were measured using a superconducting quantum interference device （SQUID）. Both monodisperse MnFe204 nanocrystals with spherical and triangle-shapes are superparamagnetic at room temperature while ferromagnetic at 2 K. The pyrolysis method may provide an effective route to synthesize other spinel ferrites or metal oxides nanocrystals.

Synthesis and Properties of Novel Surface Active Maleic Monomer Containing Phosphate Group

A novel surface active monomer （surfmer） containing poly（ethylene glycol） chain and terminated phosphate group was synthesized. The copolymerization of synthesized surfmer with NVP （N-vinylpyrrolidone） and with NVP and VEP （5-tert-butylperoxy-5-methyl-2-hexene-3-yne monomer） led to formation of corresponding surface-active copolymers. The capability of application of resulted copolymers as surface active macroinitiators of emulsion polymerization of styrene and as components of polymeric scaffolds was investigated.

Flexible SnS nanobelts： Facile synthesis, formation mechanism and application in Li-ion batteries

[020]-oriented tin sulfide nanobelts with a length/thickness ratio of 100 have been synthesized by a facile hydrothermal method without any surfactants, and the nanobelts have shown good strain-accommodating properties as well as good electrochemical performance as the anode for Li-ion batteries. The formation of the nanobelts results from a precipitation-dissolution-transformation mechanism, and the [020] oriented growth can be ascribed to the {010} facet family having the lowest atomic density. In particular, SnS shows clear Li-Sn alloying/de-alloying reversible reactions in the potential range 0.1-1.0 V. Based on galvanostatic measurements and electrochemical impedance spectroscopy, SnS nanobelts have shown impressive rate performance. The post-cycled SnS nanobelts were completely transformed into metallic tin, and preserved the one-dimensional structure due to their flexibility which accommodates the large volumetric expansion.

Tunable gold nanostar synthesis with surfactant-free system

Gold nanoparticle is an important photothermal conversion material in photothermal imaging and photothermal therapy research.There are diverse gold nanoparticles,including gold nanospheres,gold nanorods,gold nanocages,gold nanoshells and gold nanostars.Among them,gold nanostar(AuNS)possesses more excellent prospective imaging contrast agent for cancer diagnosis than other shapes of gold nanoparticles because of its larger photon interception area and cross section as well as scattering characteristics.The properties of AuNS are susceptible to synthetic methods and conditions.In this study,we presented surfactant-free methods to synthesize AuNS,discussed the relationship of AuNS characterization with the synthetic conditions and tested its photothermal effect.The results indicated that length and number of branches in AuNSs were the main factor for absorption wavelength in photothermal conversion,and the Au NSs could be more precisely controlled by changing the synthesis conditions.