丙烯中砷元素的ICP-AES分析

本文介绍了以一种吸收液将丙烯气中的砷吸附下来，然后利用ICP－AES对其进行分析的研究。文中详述了实验方法及结果的讨论。     

椭圆偏振光谱法对固体和液体界面上抗原抗体反应动力学的研究

用气相沉积法将Ｎ－β－γ－氨丙基三甲氧基硅烷沉积在单晶硅表面，并用戊二醛将正常兔ＩｇＧ抗原固定在硅烷化后的单昌硅表面上，然后用椭圆偏振光变法对固－液界面上的正常兔ＩｇＧ抗原与羊－抗兔体反应动力学特性进行了研究。     

内分泌干扰物雌酮分子印迹新型吸附功能材料的制备及其选择性能研究

采用分子印迹本体聚合法,制备了对内分泌干扰物雌酮具有高选择识别能力的分子印迹聚合物。吸附动力学和选择性实验结果表明,与非印迹聚合物相比,印迹聚合物具有较高的吸附容量和吸附速率,对模板分子具有较高的选择性。聚合反应条件对印迹聚合物的吸附和识别性能有重要影响,以丙烯酰胺为功能单体,模板分子、功能单体和交联剂摩尔比为1:3:6,制备的印迹聚合物具有较高的选择和吸附性能。     

ICP—MS法测定土壤中十五种稀土元素

采用微波消化土壤样品,通过优化等离子体功率、雾化器流量等仪器参数,找出最佳的测定条件,直接测定了土壤中Y、La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu15种稀土元素含量。结果表明,各个元素的方法检出限为0．004—0．024ng／mL,样品的检出下限为0．09—0．30ng／mL,结果较为满意。     

Krasnoselskii type fixed point theorems and applications

In this paper, we establish two fixed point theorems of Krasnoselskii type for the sum of , where is a compact operator and may not be injective. Our results extend previous ones. As an application, we apply such results to obtain some existence results of periodic solutions for delay integral equations and then give three instructive examples.

     

One-Step Manufacturing of Supramolecular Liquid-Crystal Elastomers by Stress-Induced Alignment and Hydrogen Bond Exchange

Liquid-crystal elastomers (LCEs) capable of performing large and reversible deformation in response to an external stimulus are an important class of soft actuators. However, their manufacturing process typically involves a multistep approach that requires harsh conditions. For the very first time, LCEs with customized geometries that can be manufactured by a rapid one-step approach at room temperature are developed. The LCEs are hydrogen bond (H-bond) crosslinked main chain polymers comprising flexible short side chains. Applying a stretching/shear force to the LCE can simultaneously induce mesogen alignment and H-bond exchange, allowing for the formation of well-aligned LCE networks stabilized by H-bonds. Based on this working principle, soft actuators in fibers and 2D/3D objects can be manufactured by mechanical stretching or melt extrusion within a short time (e.g. <1 min). These actuators can perform reversible macroscopic motions with large, controlled deformations up to 38 %. The dynamic nature of H-bonds also provides the actuators with reprocessability and reprogrammability. Thus, this work opens the way for the one-step and custom manufacturing of soft actuators.     

Sulfonylamidine-substituted derivatives of avibactam: Synthesis and antibacterial activity

Avibactam is a clinically approved non-β-lactam based β-lactamase inhibitor. Derivatization of this scaffold with improved inhibition profile is the demand of the day to cope with the future challenges. We successfully synthesized new derivatives of avibactam containing sulfonylamidine moieties at C2 position of the diazabicyclooctane ring. We tested in vitro antibacterial activities of newly synthesized compounds against 10 bacterial strains expressing variable β-lactamases. All compounds did not exhibit antimicrobial profile when assayed individually; however, all compounds minimized the MIC value of the imipenem in combination. Compound 5l proved most potent against all 10 bacterial strains, and showed improved inhibition against six bacterial strains as compared with the control inhibitor, relebactam. The compound 5l may be a lead hit for future development.     

一种基于2D-CNN的激光超声表面缺陷检测方法

激光超声表面缺陷检测的过程中,缺陷的定量表征通常依赖于操作者的判断,易受到人为因素干扰,致使检测结果不稳定。针对这一问题,提出一种基于图像识别的二维卷积神经网络（2D-CNN）的缺陷自动分类检测方法。利用有限元方法模拟激光超声检测过程,并采集超声信号数据用于训练分类模型;使用连续小变换（CWT）处理超声信号得到小波时频图,以小波时频图作为输入训练卷积神经网络（CNN）分类模型,实现对表面缺陷深度的自动分类。验证结果表明:提出的检测方法能够对不同深度的缺陷准确分类,测试的平均准确率达到97.3%;构建的CNN分类模型能够自主学习输入图像的缺陷特征并完成分类,提高了检测结果稳定性,为激光超声缺陷检测的自动化分析处理提供了新的思路。     

Ag/Co-Ce复合氧化物在O2及NOx气氛中催化燃烧碳烟的性能:Ag的作用

柴油车由于其良好的燃油经济性及强劲的动力得到了广泛应用,但同时柴油车尾气排放中颗粒物(PM)也对环境造成巨大污染,并严重威胁人类健康.与气体污染物相比,PM的处理难度更大,其组分复杂,起燃温度高,是当前柴油车排放问题的瓶颈和难点.颗粒过滤器(DPF)是一种有效消除PM的手段,它需要及时再生以保证其较高的碳烟捕集效率.与其他再生方案相比,连续催化再生系统工艺简单,能耗低,研发一种能够连续催化再生柴油车DPF的催化剂也成为当务之急.Ag是一种比较特殊的贵金属,其工业属性较强,价格也相对低廉.Ag基催化剂在环境催化领域有着广泛应用,已被应用于CO催化氧化、VOC催化去除及甲醛催化氧化等领域.目前的文献报道主要集中于研究Ag基催化剂负载于惰性载体对O2气氛下碳烟起燃性能的影响,并基于此讨论Ag的作用.本文利用柠檬酸络合法合成了高性能低温催化氧化材料体系xAg/Co0.93Ce0.07,探讨了不同Ag负载量对在两种气氛O2及O2+NO中催化性能的影响,并深入分析了引起此现象的原因.结果表明,Ag对Co-Ce复合氧化物的催化性能有显著的促进作用;Ag/Co-Ce复合氧化物在O2气氛下的起燃活性取决于Ag含量,Ag含量最高的样品0.3Ag/Co0.93Ce0.07催化性能最佳.而在NOx气氛下,Ag基催化剂的起燃性能不及在O2中的数值;0.2Ag/Co0.93Ce0.07与0.3Ag/Co0.93Ce0.07催化活性并列最优,其起燃温度可低至226oC.XRD及Raman的表征结果证实了Ag主要以单质形态存在,且其对Co-Ce复合氧化物的晶体结构未产生显著的影响,Ag的晶粒尺寸也未明显变化.H2-TPR则表明了Ag的负载未能提高催化剂的整体氧化还原能力,soot-TPR预示Ag甚至恶化了催化剂在惰性气氛下表面晶格氧及体相晶格氧的活性.NOx-TPD表征结果则证明了Ag对催化剂的NOx吸附有积极作用.此外,Ag/Co-Ce复合氧化物催化剂也具备了优异的耐久性及稳定性.本文还依据催化性能及表征结果剖析了碳烟在不同气氛下的催化氧化机理.在O2气氛下,Ag为反应的活性位,Ag与其表面的氧化物层AgOy之间存在一个自再生的反应循环.Ag吸附解离氧原子后,将其转化为AgOy,这表明此氧化物层不仅能够在低温下贡献表面晶格氧去除碳烟,促进氧分子向超氧物种转化,它在分解后也能将吸附氧解离为过氧物种及超氧物种.在NOx气氛下,催化剂表面硝酸根物种是催化剂催化性能维持稳定的重要因素;反应过程中催化材料表面硝酸盐物种的热稳定性筛查结果也进一步佐证了催化剂表面的AgNO3物种是碳烟起燃的决定性因素,其自身的氧化还原活性及Ag离子移动性均有利于降低碳烟的起燃温度.TGA结果说明了NOx气氛中的活性中间产物AgNO3的氧化还原活性劣于O2气氛下活性中间产物Ag2O,这直接导致催化剂在O2气氛下具备更好的碳烟起燃性能.本文工作有助于启发其他研究者开发高活性催化氧化催化材料.