Ti/α-PbO2/β-PbO2电极电化学降解2-氯酚

采用电化学沉积法在Ti基底上制备了复合电极Ti/α-PbO2/β-PbO2,扫描电镜结果表明电极呈现由β-PbO2小晶体组成的菜花状微观形貌.所制电极在电化学降解环境污染物2-氯酚时表现出较高的电催化效率、较好的电极稳定性和较长的电极寿命.用正交实验优化了电化学降解2-氯酚的实验条件.在最优的实验条件(2-氯酚初始浓度50 mg/L,电解质0.1 mol/L Na2SO4,温度35oC,阳极电流密度20 mA/cm2)下电化学降解180 min后,2-氯酚的去除率达100%.动力学结果表明, Ti/α-PbO2/β-PbO2电极上2-氯酚的电化学氧化符合准一级动力学过程.     

Surface Modification of Polypropylene by Ethylene Plasma and Its Induced β-Form in Polypropylene

This study aims to investigate the chemical structure and morphology of plasmapolymers produced by deposition of ethylene on the surface of polypropylene. The deposition films(sediments) of ethylene plasma on the surface of polypropylene are nonuniform, and the characterization results indicate the existence of hydroxyl groups and aldehyde(or ketone) groups in the sediments. The sediment of ethylene plasma on the polypropylene surface could induce the growth of β-form crystals in the surface layer of polypropylene.     

2-羟丙基-β-环糊精与二茂铁衍生物超分子胶束通过氧化还原响应控制药物释放

合成了新型的具有长链的二茂铁衍生物(P-Fc),并将其包络在2-羟丙基-β-环糊精(HP-β-CD)的空腔中,自组装形成超分子囊泡,并通过FTIR、1 HNMR、SEM和CV曲线对其进行结构形貌表征;分别以罗丹明6G(R6G)、盐酸阿霉素(DOX)作为药物,实现了R6G、DOX在囊泡中的成功装载。并通过加入氧化剂,将二茂铁氧化成二茂铁盐,将囊泡破坏,实现了 R6G 和 DOX 的快速定向释放,其药物装载量分别为6.89和39.06μg/mg,最大释放率分别为73.7%和88.2%。     

自组装短肽GFS-2构建新型三维细胞培养支架材料

典型的自组装短肽在水中可形成稳定的β-sheet二级结构,在生理性环境下则能够形成稳定的纳米纤维,可进一步形成含水量达99%的水凝胶,具有高纯度、可降解及无免疫反应等突出优点,能模拟生物体内的三维基质环境而作为细胞三维培养的新型生物材料。本文主要采用了圆二色谱仪、原子力显微镜、倒置显微镜等探究新型短肽GFS-2的自组装性能及其在细胞三维培养中的应用。此研究可能会启发设计更多的新型自组装短肽服务于化学、生物材料、医学工程等领域。     

丙二硫醚桥联双β-二酮与Ni(Ⅱ)配位作用及液膜传输性研究

合成了丙二硫醚桥联2个乙酰丙酮的双β-二酮分子1,3-二(3-硫醚基-2,4-戊二酮基)丙烷(L1),以此为配体与镍(Ⅱ)作用得到配合物,通过元素分析和摩尔电导分析方法确定了镍(Ⅱ)配合物的化学组成,比较分析了配位前后的游离配体与配合物的红外及紫外吸收光谱,采用紫外光谱滴定法对配体L1与Ni(Ⅱ)离子在溶液中的配位行为进行了模拟研究,并进行金属离子液膜传输实验考察了L1对Ni(Ⅱ)的液膜传输性能。结果显示,L1通过4个O原子与Ni(Ⅱ)配位成键形成配合物,且对Ni(Ⅱ)具有良好的液膜传输性。     

B,P掺杂β-Si3N4的电子结构和光学性质研究

运用第一性原理方法, 计算了B, P两种元素单掺杂和共掺杂的β -Si₃N₄材料的电子结构和光学性质. 结果表明: B掺杂体系的稳定性更高, 而P掺杂体系的离子性更强; 单掺和共掺杂均窄化带隙, 且共掺在禁带中引入深能级, 使局域态增强; 单掺杂体系介电函数虚部、吸收谱和能量损失谱各峰均发生红移、幅值减小, 而共掺后介电函数虚部主峰出现蓝移、能量损失峰展宽、高能区电子跃迁大大增强, 且控制共掺杂的B, P比例可获得较低的带电缺陷浓度.     

基于实测荷载的铁路钢桁梁桥疲劳可靠性评估

为了对钢桁梁桥疲劳进行评估,引入可靠性理论,提出了基于实测荷载的桥梁疲劳可靠性评估方法。根据某铁路钢桁梁桥实测车辆荷载数据,建立了随机车辆荷载模型。并在考虑车辆荷载随机性的基础上,结合Monte-Carlo法与有限元,分析了钢桁梁桥构件疲劳应力谱,计算了构件疲劳可靠性随时间的变化,并探讨了车辆荷载及荷载效应变异性对构件疲劳可靠性的影响,最后采用β约界法与静力分析法对钢桁梁桥系统疲劳可靠性进行了研究。结果表明,基于随机车辆荷载的构件疲劳应力谱呈现单峰分布;构件疲劳可靠性随运营时间的增加而减小;车辆荷载的增长及荷载效应变异性的增加对构件疲劳可靠性影响较大,当车辆荷载增长率和等效应力变异系数分别增加到5%时,构件疲劳寿命大幅减小;β约界法结合静力分析法可快速确定钢桁梁桥失效模式,桥梁系统疲劳寿命小于构件疲劳寿命。总的来看,基于实测荷载的钢桁梁桥疲劳可靠性评估方法能有效地利用监测数据,对桥梁疲劳评估具有良好的适用性。     

Molecular chaperone-like properties of sodium caseinate to suppress the pressure-induced aggregation of β-lactoglobulin

ABSTRACT

The objective of this study was to determine whether sodium caseinate can inhibit the aggregation of whey protein induced by pressure treatment. Solutions of β-lactoglobulin (β-Lg, 0.2%, w/v) and mixtures containing 0.2% (w/v) β-Lg and 0–0.5% (w/v) sodium caseinate (NaCas) were pressurized at 400–800?MPa. NaCas suppressed the aggregation of β-Lg induced by pressure treatment, and this function was dependent on the concentration of NaCas. Furthermore, NaCas altered the aggregation process of β-Lg by suppressing the transition of the aggregate from the soluble phase to the insoluble phase and, as a result, the fraction of insoluble aggregates was decreased. During this process, NaCas formed stable complexes with the denatured β-Lg, and the formation of complexes prevented further aggregation of β-Lg. These results indicate that NaCas exhibits a chaperone-like activity under high pressure.     

Progress toward the total synthesis of 9β-hydroxyvertine: Construction of an advanced quinolizidine intermediate

Progress toward the total synthesis of 9β-hydroxyvertine 2 is described. Our approach involves a Petasis borono-Mannich reaction to assemble a key intermediate A, securing the correct configuration at H-9 and H-10 in the final targeted molecule. Subsequent formation of the quinolizidine framework B allowed the synthesis of an advanced intermediate containing all but the lactone moiety of 2. Our unsuccessful attempts at introducing this lactone feature are also described.