超临界萃取技术结合超声强化技术提取鹿茸中性激素和IGF-1

Supercritical CO2 (SC-CO2) extraction technology and ultrasonic technology were used to extract two active sex hormones, estradiol and progesterone, and insulin-like growth factor-1 (IGF-1) from antler velvet. The effects of SC-CO2 extraction condition on the extraction yield and content of sex hormones, the ultrasonic extraction condition on the content of IGF-1 and the SC-CO2 extraction condition on the activity remaining of IGF-1 were studied. The optimal conditions were obtained. The experimental results showed that, in presence of 75% ethanol as the co-solvent, the mean yield and content of estradiol and progesterone were 87.67 pg•g－1 and 1224.10 pg•g－1, 12.38 ng•g－1 and 354.06 ng•g－1, respectively, with extraction pressure of 30 MPa, temperature of 35°C, extraction time of 30 min and CO2 consumption of 15 L•g－1 at the flow rate of 2.0 L•min－1. The highest content of IGF-1 was 7425.75 ng•g－1 antler velvet residue, when the pH10 ammonia-ammonium chloride buffer solution was used as the solvent, the ratio of solvent to sample was 20/1 (volume/mass), the extraction temperature was 0-35°C, and the ex-traction time was 4×15 min. Under these conditions, 93.68% activity remaining of IGF-1 in the residue was ob-tained, while little IGF-1 activity exists in traditional residue. The experimental results indicate that the technology of SC-CO2 with co-solvent is of advantage for getting high content sexual hormones and keeping high activity of IGF-1 in the residue, which can not be achieved by traditional extraction methods.     

第三分散相液滴增强气体吸收的一维非稳态非均相传质模型

A model for one-dimensional unsteady heterogeneous mass transfer was developed based on Danckwerts’ surface renewal theory in order to describe the mass transfer enhancement of absorption process for a slightly soluble gas in a gas-liquid-liquid system. The model accounts for the mass transfer resistance within the dispersed phase and the effect of emulsion viscosity on mass transfer. An analytical solution for enhancement factor was obtained by Laplace domain transformation. The absorption rates of carbon dioxide in the dodecane-in-water and castor oil-in-water systems were measured in a thermostatic reactor, and the enhancement factors were calculated at different volume fractions of dispersed phase and stirrer speeds. The model predictions agree well with the experi-mental data.     

生物燃料热力学分析方法研究进展

介绍了基于净能量、有效能和能值的三种热力学分析方法的基本原理和方法评价,以及对玉米燃料乙醇等生物燃料的能量效益、环境效益和可持续性等复杂问题分析的应用进展,最后指出从热力学角度评价以玉米燃料乙醇为代表的生物燃料的综合效益所面临的挑战。     

Contribution of electrochemical dissolution during pickling of low carbon steel in acidic solutions

An electrochemical cell coupled with ICP-OES chemical analysis was used to explore the role of chemical and electrochemical reactions in pickling of low carbon steel in acidic media. Impedance spectroscopy was used to highlight scale properties. Dissolution of hematite is shown to be mainly of chemical nature, whereas the dissolution of magnetite and wüstite is both chemical and electrochemical. Initially, chemical dissolution of the scale dominated. The electrochemical reactions included oxidation of magnetite and wüstite and reduction of ferric ions formed by chemical dissolution. After the electrolyte reached the steel substrate, electrochemical dissolution of the iron was the main reaction.     

Preparation of continuous carbon nanotube networks in carbon fiber/epoxy composite

In order to optimize carbon nanotube (CNT) dispersion state in fiber/epoxy composite, a novel kind of CNT organization form of continuous networks was designed. The present work mainly discussed the feasibility of preparing continuous CNT networks in composite: Fiber fabric was immersed into CNT aqueous solution (containing dispersant) followed by freeze drying and pyrolysis process, prior to epoxy infusion. The morphologies of fabric with CNTs were observed by Scanning Electron Microscope. The relationship between CNT networks and flowing epoxy resin was studied. Properties of composite, including out-of-plane electrical conductivity and interlaminar shear strength (ILSS), were measured. The results demonstrated that continuous and porous CNT networks formed by entangled CNTs could be assembled in fiber fabric. Most part of them were preserved in composite due to the robustness of network structures. The preserved CNT networks significantly improved out-of-plane electrical conductivity, and also have an effect on ILSS value.     

Study on the preparation of Ni–La–Ce oxide catalyst for steam reforming of ethanol

Two schemes for design and preparation of Ni–La–Ce oxide catalysts for steam reforming of ethanol were proposed in this work. The one via citrate complexing method was designed as NiO supported on ceria-lanthanum oxide (CL) solid solution, in which the strong interaction between NiO and CL solid solution was beneficial to inhibit the aggregation of NiO particles, and the abundant of oxygen vacancies existed in CL solid solution was in favor of carbon elimination from catalyst surface. The other was schemed as LaNiO₃ with perovskite structure loaded on CeO₂ support by using impregnation method, in which the particles of metal Ni derived from reduction of LaNiO₃ were highly dispersed, and the formation of La₂O₂CO₃ in the reaction process could act as the carbon scavenger. Both of the catalysts exhibited very good performance for steam reforming of ethanol (SRE), complete C₂H₅OH conversion was obtained with 70.3% of H₂ selectivity at 400 °C over the catalyst obtained from former method and complete C₂H₅OH conversion was achieved at 450 °C with 67% of H₂ selectivity over the catalyst from latter method. The catalyst made according to the citrate complexing method was more active for SRE and more selective for H₂ production. Both of the catalysts displayed very good anti-sintering ability which was tested at 650 °C and at a high space velocity of 180,000 ml g_cat⁻¹ h⁻¹ with reaction mixture of H₂O/C₂H₅OH = 3 in mole ratio. The results indicated that both of oxygen vacancy and La₂O₂CO₃ possessed the ability to remove the deposited carbon, and compared with La₂O₂CO₃ the oxygen vacancy could reduce one third more of the carbon deposited according to TG tests.     

海水基耐温聚丙烯酰胺压裂液的性能优化

以丙烯酰胺、丙烯酸和2-丙烯酰胺-2-甲基丙磺酸（AMPS）三元共聚物（PSAM）为稠化剂,乳酸锆为交联剂开发出一种海水基耐高温压裂液,考察了PSAM的水解度、相对分子质量、AMPS含量、稠化剂和交联剂的浓度、配比等因素对冻胶形成及耐温耐剪切性能的影响,通过测试不同条件下冻胶的储能模量（G'）随时间的变化,研究了Ca²⁺浓度和AMPS含量对交联动力学的影响。交联动力学的研究表明,随AMPS含量加大,PSAM交联速度降低,达到交联平衡所需时间延长,随Ca²⁺浓度增高,交联反应速度越快,冻胶初始强度越高;耐温性能测试表明,当稠化剂中羧酸基含量与交联剂中锆离子含量之比n（-COOH）/n（Zr⁴⁺）≈1时,体系的耐温耐剪切性能最优,高含量AMPS提升压裂液的耐温耐剪切性能。在优化稠化剂结构条件下,稠化剂质量分数为0.6%、交联剂质量分数为0.3%配制的海水基压裂液,在150℃、170 s^-1下剪切120 min后,黏度保持在150 mPa·s以上,耐温耐剪切性能优秀。     

Behavior of AlxMgFeZn-alloy through microhardness,microstructure, thermal treatment and electrodissolution

Microstructural changes induced by aged treatment shown a connection between differences of microhardness and electrodissolution. AlxMgFeZn alloys were prepared by metal mold casting method in order to diminish the process cost generating an alloy with homogenous microstructure and less casting porosity. In addition, was correlated the influence of chemical composition with the thermal treatment on the electrochemical dissolution or electrodissolution. With all this in mind, the AlxMgFeZn alloy has been studied by means of microhardness, X-ray diffraction, scanning electron microscopy, and short-term electrochemical test.The formation of Mg₃Zn₃Al₂ precipitate phase was identified for two conditions, the first one is when the chemical composition of magnesium is upper to 5.49% in as-cast condition and the second one is influenced by the thermal treatment of aging. In addition, the microhardness and electrochemical dissolution has been influenced by the presence and quantity of the Mg₃Zn₃Al₂ phase. The chemical composition of magnesium alloying modifies the microstructure, increases the content of Mg₃Zn₃Al₂ phase and, provides a localized dissolution on the AlxMgFeZn alloy surface.     

Grafting of phosphorylcholine functional groups on polycarbonate urethane surface for resisting platelet adhesion

In order to improve the resistance of platelet adhesion on material surface, 2-methacryloyloxyethyl phosphorylcholine (MPC) was grafted onto polycarbonate urethane (PCU) surface via Michael reaction to create biomimetic structure. After introducing primary amine groups via coupling tris(2-aminoethyl)amine (TAEA) onto the polymer surface, the double bond of MPC reacted with the amino group to obtain MPC modified PCU. The modified surface was characterized by Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The results verified that MPC was grafted onto PCU surface by Michael reaction method. The MPC grafted PCU surface had a low water contact angle and a high water uptake. This means that the hydrophilic PC functional groups improved the surface hydrophilicity significantly. In addition, surface morphology of MPC grafted PCU film was imaged by atomic force microscope (AFM). The results showed that the grafted surface was rougher than the blank PCU surface. In addition, platelet adhesion study was evaluated by scanning electron microscopy (SEM) observation. The PCU films after treated with platelet-rich plasma demonstrated that much fewer platelets adhered to the MPC-grafted PCU surface than to the blank PCU surface. The antithrombogenicity of the MPC-grafted PCU surface was determined by the activated partial thromboplastin time (APTT). The result suggested that the MPC modified PCU may have potential application as biomaterials in blood-contacting and some subcutaneously implanted devices.