自制双层固相萃取柱在新会陈皮及其制品中11种有机磷农药测定中的应用

以自制改性多壁碳纳米管（MWNTs）和N-丙基乙二胺（PSA）填料分层填装的双层固相萃取柱为净化柱,建立了测定陈皮及其制品中11种有机磷农药残留的分析方法。样品经乙酸乙酯提取、离心后,固相萃取柱净化,净化液经Agilent RTS-1701毛细管柱分离,火焰光度检测器检测,外标法定量。考察了填料类型、填料用量、洗脱方式等因素对提取效率的影响。在优化条件下,11种有机磷农药检测的线性范围为0.020~1.0 mg/L,相关系数为0.9990~0.9998,检出限为3.5~9.6 μ g/kg。样品在10、25、100 μg/kg 3种水平下的加标回收率为50.8%~109%,相对标准偏差为2.7%~8.5%。该法准确度和灵敏度高、操作简单、快速,检出限能满足对有机磷农药残留的限量要求。自制固相萃取柱可降低成本,值得推广应用。     

型钢再生混凝土组合柱水平承载力试验及计算方法研究

基于17个型钢再生混凝土组合柱低周反复荷载试验,分析了再生粗骨料取代率、轴压比、体积配箍率以及剪跨比对组合柱水平承载力的影响规律。通过实测型钢腹板与翼缘,箍筋及纵筋的荷载-应变曲线,并结合组合柱的破坏形态特征,分析了型钢再生混凝土组合柱在水平荷载作用下的破坏机理。在此基础上,分别推导了型钢再生混凝土组合柱发生剪切斜压破坏和弯曲破坏时的理论计算公式。为了便于计算,本文提出了型钢再生混凝土组合柱水平承载力实用计算公式。结果表明,组合柱的计算水平承载力与试验值吻合较好,满足计算要求。上述研究结论可为型钢再生混凝土组合柱的抗震设计提供参考。     

L、T、十形截面型钢混凝土异形柱滞回性能对比分析

为了研究截面形状对型钢混凝土(SRC)异形柱滞回性能的影响,完成了4个L形、6个T形和2个+形截面SRC异形柱构件的低周反复荷载实验,并获取了此类构件的破坏形态和滞回曲线。在此基础上,对比分析了截面类型对SRC异形柱在耗能能力、变形性能及地震损伤等方面的影响。研究结果表明:型钢混凝土异形柱的破坏形态与剪跨比有关,剪跨比大的试件易发生弯曲型破坏,而小剪跨比的试件易发生剪切型破坏;L形柱的滞回环捏拢程度最大,其次为T形柱,最后为+形柱;+形柱和L形柱的相对受剪承载能力和耗能能力均比T形柱大;T形柱的变形能力要优于L形柱;型钢混凝土异形柱构件的相对损伤累积程度与柱肢数有关,其主要表现为随着柱肢数的增多,异形柱的损伤发展水平加快。     

往复加载下隔板贯通式箱型中柱-削弱型H型钢梁节点破坏机理研究

为研究箱型柱-H型钢梁节点在强震时的脆断机理和延性节点构造, 对4个隔板贯通式箱型中柱-H型钢梁节点试验(1个常规节点和3个对接焊缝扩大头及梁翼缘圆孔削弱型节点)进行了低周往复循环加载试验和基于结构钢椭球面断裂模型及偶联的椭球面屈服模型的断裂分析. 结果表明: 隔板贯通式箱型中柱-H型钢梁常规节点在应力高度集中的梁翼缘对接焊缝处脆断; 扩大头构造消除了对接焊缝沿梁翼缘宽度的几何突变, 降低了对接焊缝的应力集中程度和脆断风险; 梁翼缘上开设的圆孔构造促使塑性铰形成于远离节点区的梁削弱截面; 对接焊缝扩大头及梁翼缘圆孔削弱型节点的承载力较常规节点降低5.5%~9.4%.     

Manipulation of Supramolecular Columnar Structures of H-Bonded Donor-Acceptor Units through Geometrical Nanoconfinement

Ambipolar organic semiconductors are considered promising for organic electronics because of their interesting electric properties. Many hurdles remain yet to be overcome before they can be used for practical applications, especially because their orientation is hard to control. We demonstrate a method to control the orientation of columnar structures based on a hydrogen (H)-bonded donor-acceptor complex between a star-shaped tris(triazolyl)triazine and triphenylene-containing benzoic acid, using physicochemical nanoconfinement. The molecular configuration and supramolecular columnar assemblies in a one-dimensional porous anodic aluminium oxide (AAO) film were dramatically modulated by controlling the pore-size and by chemical modification of the inner surface of the porous AAO film. In situ experiments using grazing-incidence X-ray diffraction (GIXRD) were carried out to investigate the structural evolution produced at the nanometer scale by varying physicochemical conditions. The resulting highly ordered nanostructures may open a new pathway to effectively control the alignment of liquid crystal ambipolar semiconductors.     

Preparation of a capillary isoelectric focusing column with monolithic immobilized pH gradient and its application on protein separation based on an online capillary isoelectric focusing platform

In the presence of methanol and n‐decanol as porogens, a partially filled capillary monolithic column was prepared by in situ reaction of glycidyl methacrylate and poly (ethylene glycol) diacrylate. Then, Pharmalyte 3–10 was immobilized on this column in order to obtain a capillary isoelectric focusing (cIEF) column with monolithic immobilized pH gradient (M‐IPG). In addition, an online self‐built platform for protein separation was established on account of the introduction of a cross‐shaped unit and two short‐off valves. In this platform, a cross‐shaped unit was not only used to join the M‐IPG column and a six‐way injection valve (1.5 μL sample loop), but also to supply a volume pool of anode buffer so that the process of injection, focusing and mobilization of samples could be sequentially performed. The short‐off valve in the tee unit or cross‐shaped unit could be used to control the direction of the fluid flow. Using this online cIEF platform and under the optimized conditions, 7‐proteins mixture could be separated and a good linear correlation between pI values and migration times was obtained by the M‐IPG column. Meanwhile, based on the online cIEF platform, human serum proteins and a mixture of Hb A and Hb A_1c have been successfully resolved with the newly developed M‐IPG column.     

Removal of cationic dyes by modified waste biosorbent under continuous model: Competitive adsorption and kinetics

Modified waste sugarcane bagasse (SCB) was prepared to remove cationic dyes: methylene blue and rhodamine B from aqueous solution by using a continuous mode. Effects of flow rate on adsorption of the two dyes in fixed bed column were studied. Competitive adsorption kinetics of the two dyes in binary system was investigated in detail. Results showed that the adsorption capacities of the modified sorbent for methylene blue and rhodamine B in one component system were 1.7 and 0.4 mmol g^?1, respectively. Competitive adsorption process in the binary system could be divided into three phases: free adsorption, substitution adsorption and adsorption equilibrium. 0.19 mmol of rhodamine B absorbed was replaced by 0.35 mmol of methylene blue in the second phase. Simple modified Yoon–Nelson model was used to predict the adsorption kinetics for the first time. The obtained adsorption rate constants for the two dyes in the three phases both followed the order: phase I > phase III > phase II, demonstrating that substitution adsorption phase is the rate determining step. Desorption experiment showed that the loaded two dyes could be separated and recycled by using the mixture solution of HCl (0.1 mol L^?1) and ethanol as eluent. The prepared fixed bed column had great potential in industrial wastewater treatment.     

Fluid model of the positive column in argon‐oxygen direct current glow discharge

The positive column of argon‐oxygen direct current (DC) glow discharge was investigated using a fluid model at pressures of around 410 Pa and discharge currents from 10 to 40 mA. The model was used to study the influence of an oxygen admixture on the properties of argon discharge. The simulated intensity of the electric field strength was compared with measured values at 5% and 100% of oxygen concentration. The one‐dimensional model in a cylindrical tube is based on the drift‐diffusion approximation of particle flux and the mean‐electron‐energy approximation is used to describe the electron interaction. The model takes into account the radial profile of particle concentration, the neutral gas kinetic temperature profile, and interactions with the wall in the cylindrical glass discharge tube. It was shown that 2% of the oxygen admixture causes a significant increase in longitudinal electric field strength and gas heating.     

液体电极上辉光放电丝的运动特性研究

大气压液体电极放电在生物医疗、化学降解、环境保护等众多方面具有广泛的应用前景,引起了研究者的关注.本文利用直流电压激励棒-水电极装置,在6 mm气隙间产生了大气压辉光放电.研究发现,随着电流的增大,放电由锥状转变成柱状,且此过程中水面上放电环的直径先增大后减小.利用高速照相机对放电进行研究,发现锥状放电是由单个放电丝旋转形成的.通过测量放电的伏安特性,表明放电处于正常辉光机理.利用光谱学方法,研究了不同电流下的振动温度、转动温度和谱线强度比I_(391.4)/I_(337.1),发现它们均随电流的增加而增大.根据气体放电理论,分析和解释了放电丝的运动机理,并对水面上放电环直径随电流的变化关系进行了解释.这些结果对于大气压液体电极放电的理论研究和实际应用均具有一定参考价值.     

复合免疫亲和柱-高效液相色谱法同时测定谷物及其制品中9种真菌毒素

建立了复合免疫亲和柱-在线光化学衍生-高效液相色谱同时测定谷物及其制品中9种真菌毒素的检测方法。以乙腈-水（80：20,v/v）混合溶液提取样品中9种真菌毒素,提取液经自制真菌毒素复合免疫亲和柱净化,采用高效液相色谱进行分离,在线光化学衍生后进入荧光检测器测定,外标法定量。结果表明,9种真菌毒素在相应浓度范围内线性关系良好,相关系数均大于0.999;在低、中、高3个不同加标浓度下,9种真菌毒素的回收率均大于80%,相对标准偏差（RSD）为1.0%~5.6%;方法的检出限（LOD）为0.02~5.00 μg/kg,定量限（LOQ）为0.07~16.70 μg/kg。该方法具有重现性好、灵敏度高、结果准确的特点,适用于谷物及其制品中9种真菌毒素残留的分析检测。