全自动自适应网格细化

本文利用弹塑性误差估计模型，预示出金属成形数值模拟过程中网格细化时新网格尺寸，提出补角法修正锻件边界构形并利用三次Ｂ样条统一表达边界构形，实现了对边界细化并进而产生自适应细化网格。     

考虑水弹性影响的水下航行体结构动响应研究

考虑水弹性的影响,计及惯性力、水动力和弹性力之间的相互耦合作用,将水动力学方程和结构动力学方程联合求解,采用三维势流理论和边界元法推导并计算了水下航行体结构的附加质量矩阵,对带空泡水下航行体出水过程中的结构动响应问题进行了分析.      

高效液相色谱快速测定草本植物饮料中28种外源性药物和内源性成分

建立了高效液相色谱快速测定草本植物饮料中28种外源性药物和内源性成分的分析方法。样品经甲醇-水（70：30,v/v）超声提取后,使用Thermo Accucore C18色谱柱（100 mm×4.6 mm,2.6 μm）,以甲醇、乙腈和20 mmol/L乙酸铵溶液（pH 4.2）为流动相进行梯度洗脱,流速为1.2 mL/min,柱温为35℃,采用二极管阵列检测器,检测波长为254和220 nm,外标法定量。结果表明,28种成分在1~100 mg/L范围内线性关系良好,相关系数（r）均不小于0.999。液体样品和固体样品的检出限（LODs）分别为1~10和20~200 mg/kg。28种成分在液体和固体样品中的加标回收率分别为88.8%~118.6%和92.7%~112.3%,相对标准偏差（RSDs）分别为0.1%~6.7%和0.1%~6.4%。按上述方法检测草本植物饮料456批,检出阳性样品55批次,检出率为12.1%。该法简便快速、准确可靠,适用于草本植物饮料中28种成分的测定。     

柔性圆柱涡激振动流体力系数识别及其特性

涡激振动是诱发海洋立管、浮式平台系泊缆和海底悬跨管道等柔性圆柱结构疲劳损伤的重要因素.目前,海洋工程中用于柔性圆柱涡激振动预报的流体力系数主要来源刚性圆柱横流向受迫振动的实验数据,存在一定缺陷和误差.本文综合考虑横流向与顺流向振动耦合作用,建立了柔性圆柱涡激振动流体力模型,运用有限元法和最小二乘法确定升力系数、脉动阻力系数和附加质量系数.为了准确识别柔性圆柱涡激振动流体力系数,设计并开展了拖曳水池模型实验,实验用柔性圆柱模型的质量比为1.82,长径比为195.5.通过与刚性圆柱流体力系数对比,深入分析了柔性圆柱流体力系数的特性.结果表明:柔性圆柱在一阶模态控制区,流体力系数随约化速度变化趋势与刚性圆柱大致相似;二阶模态控制区,升力系数和脉动阻力系数显著增大;附加质量系数在响应频率较低时与振动位移的相关性增强;当响应频率较低时,振动位移较大区域为能量耗散区,当响应频率较高时,振动位移较大区域为能量输入区.     

QuEChERS-超高效液相色谱-串联质谱法快速测定凉茶中非法添加的12种化学药物

建立了凉茶中马来酸氯苯那敏、吡罗昔康、α-细辛脑等12种非法添加的化学药物的QuEChERS结合超高效液相色谱-串联质谱(UPLC-MS/MS)的检测方法。样品经乙腈提取,应用QuEChERS技术净化,经0.22 μm微孔滤膜过滤后进行UPLC-MS/MS测定,以乙腈-0.1%(v/v)乙酸水溶液为流动相梯度洗脱,在XBridge BEH C₁₈柱(100 mm×2.1 mm, 3.5 μm)上实现12种化学药物的基线分离。该方法采用多反应监测(MRM)正离子模式扫描,标准曲线外标法定量。12种待测物在各自的质量浓度范围内线性关系良好,相关系数均大于0.997,检出限为0.1~2.1 μg/L,定量限为0.4~8.0 μg/L。在3个不同添加水平下的平均回收率为62.7%~95.2%, RSD为1.3%~10.8%。应用该方法对市面上销售的74批次凉茶进行了筛查测定,部分样品的测定结果为阳性。该方法操作简单,净化效果好,灵敏度高,适用于凉茶中12种非法添加的化学药物的快速分析。     

Synthesis and Self-Association of Stimuli-Responsive Diblock Copolymers by Living Cationic Polymerization

The living cationic polymerization of several functional monomers in the presence of an added base is investigated as a possible preparation of a new series of water-soluble or stimuli-responsive copolymers. Under appropriate conditions, the polymerization allows the selective preparation of polymers with various shapes and different sequence distributions of monomer units, including stimuli-responsive block copolymers, gradient copolymers, poly(vinyl alcohol) graft copolymers, and star-shaped polymers. The stimuli-induced self-association of the diblock copolymers is also examined. An aqueous solution of the diblock copolymer with a thermo-sensitive segment undergoes rapid physical gelation upon warming to the critical temperature to give a transparent gel, and returns sensitively to the solution state upon cooling. The sharp transition of stimuli-responsive segments with highly controlled primary structure turns out to play an important role in the self-association. Small-angle neutron scattering, dynamic light scattering, and electron microscopy studies reveal that the physical gelation involves a thermosensitive micellization of diblock copolymers (core size: 18-20 nm) and subsequent micelle macrolattice formation (bcc symmetry). Based on the gelation mechanism, several stimuli-responsive gelation systems are achieved using other stimuli such as the addition of a selective solvent or compound, cooling, pH change, and irradiation with ultraviolet light.     

Catalytic conversion of defatted rice bran into value added chemicals using copper ferrite: A sustainable approach

The most crucial and demanding universal issue lies in the enrichment of sustainable drive technology. As traditional resource, petrochemical becomes increasingly scarce in the future; mankind must turn to renewable alternatives to yield liquefied fuels and valuable commodities through sustainable process. It has been reported that furan compounds serve as an excellent platform molecule derived from defatted rice bran. The current work aims at the synthesis of copper ferrite nano catalyst by microwave assisted solution incineration approach. The catalytic properties stood verified by X-ray diffraction, SEM, EDAX and BET techniques. The catalytic performance of the copper ferrite catalyst were reinforced through in-situ microwave assisted acetalization reaction of furfural with discrete solvents like methanol, ethanol, and 1-propanol at optimum reaction conditions for the preparation of wide range of commodity chemicals such as carboxylic acids, alkyl esters, di alkyl acetals, di ketones which are of commercial importance. The comparative study of relative yield of the products with different solvents is reported. The formation of the value-added products were confirmed by GC-MS, FT-IR technique. The catalysts from the reaction mixture are recovered by magnetic field.     

中兽药口服液中非法添加化学药物高分辨质谱筛查

建立了适用于中兽药口服液中167种非法添加化学药物的超高效液相色谱-四极杆静电场轨道阱质谱高通量筛查方法。样品采用0.5%甲酸乙腈-水进行振荡超声提取，电喷雾电离源（ESI）、正负离子同时扫描方式进行数据采集。通过与自建的167种化合物的基本信息及色谱-质谱信息数据库进行比对，对色谱-质谱条件、提取溶剂的种类和净化条件进行优化。将经前处理后的口服液样品上机测试后，采用Trace Finder筛查软件对数据结果进行分析。结果显示，50 ng/mL非法添加药物（头孢类和内酰胺类药物为100～200 ng/mL）上机时可定性检出。不同药物配方因基质影响，其非法添加药物的检出率略有差异。该方法可基本实现中兽药口服液中非法添加化学药物的高通量快速筛查，具备操作简便、快速高效的特点，为其他兽药剂型中非法添加药物的筛查奠定了基础。     

Dispersing behavior of recycled rubber particles

The hydrophobic nature of recycled rubber particles presently limits their use only in non-aqueous media. Recycled rubber particles were chemically modified by preparation of amphiphilic semi-interpenetrating polymer networks using poly(acrylic acid) as the hydrophilic polymer. The resulting composite particles are water dispersible and suitable for various aqueous media applications.