Electrocatalytic oxidation of ethanol and ethylene glycol on bimetallic Ni and Ti nanoparticle-modified indium tin oxide electrode in alkaline solution

Bimetallic Ni and Ti nanoparticle-modified indium tin oxide electrode(Ni–TiNPs/ITO) were prepared by a twostep ion implantation method, and their electrocatalytic activity toward the oxidation of ethanol and glycol was evaluated. The ion-implantation method is simple, low-cost and environmental friendly without the use of any binder. The Ni–TiNPs/ITO electrode were characterized by scanning electron microscopy(SEM), atomic force microscopy(AFM) and X-ray photoelectron spectroscopy(XPS). SEM and AFM showed that the nanoparticles on the Ni–TiNPs/ITO electrode had a small range of dispersion(10–20 nm) and high dispersion. Electrochemical performances were measured by cyclic voltammetry(CV) and chronoamperometrics. The Ni–TiNPs/ITO electrode exhibited much higher electrocatalytic activity and stability for ethanol and ethylene glycol oxidation than NiNPs/ITO.     

FLN用于金属离子-HEDTA配合物稳定性研究

采用函数连接型神经网络 (FLN)的方法 ,以金属离子的电荷、半径、价电子结构、电负性及适配价轨道数因子为参数 ,成功地关联了 30种已知的金属 -HEDTA配合物稳定常数logK值 ,并在此基础上 ,预报了包括所有锕系元素在内的 39种金属 -HEDTA配合物的logK值     

Reactive incorporation of Ag into porous TiO_2 coating and its influence on its microstructure,in vitro antibacterial efficacy and cytocompatibility

Ag-doped TiO_2 coatings were successfully fabricated on Ti using plasma electrolytic oxidation(PEO) in the electrolytes containing Ag or Ag_2O nanoparticles(NPs). The results showed that the different Ag sources resulted in significant variations of morphology, composition and chemical state. The thermal decomposition of Ag_2O during PEO process contributed to the formation of Ag NPs, which might reactively incorporate into TiO_2, leading to the presence of a Ca, P-rich amorphous layer between entrapped Ag NPs and the peripheral TiO_2. By contrast,Ag specie tends to be present as micro-sized clusters consisting of metallic Ag NPs in the PEO coating fabricated via Ag NPs addition. The different microstructures inevitably affected the Ag ionic release behaviour and thus antibacterial capabilities and cytocompatibilities. It is indicated that the application of Ag_2O NPs as Ag source is promising to fabricate Ag-doped PEO coating with both long-term antibacterial activity and acceptable cytocompatibility.     

青蒿素在不同电极上的电化学行为及其在血红素作用下的还原

 在20%的乙醇和B-R缓冲溶液(pH为7.2)中,分别比较了青蒿素(artemisinin,qhs)在金电极、银电极、铂电极、玻碳电极上的电化学行为,结果表明:在+0.00～-1.30V(vs.SCE)的电位范围内,青蒿素在金电极和铂电极上无氧化还原峰信号;而在银电极和玻碳电极上有一还原峰,无氧化峰,峰电位为分别-0.64V和-0.91V.此外在银电极和玻碳电极上,血红素(hemin)能够催化青蒿素的还原.     

NVP-BEZ235诱导自噬在肝癌细胞凋亡中的作用研究

目的 以Hep3B和PLC/PRF/5两种肝癌细胞为研究对象,探讨自噬在NVP-BEZ235中引起细胞凋亡的作用.方法 人类肝癌细胞Hep3B和PLC/PRF/5在含有10%FBS的DMEM培养基中进行培养,然后再进行细胞活性检测,用于Western blotting检测及线粒体膜电位(MMP)分析.结果 NVP-BEZ235能够有效增加LC3-Ⅱ的表达,并同时降低p62的表达,由此推断,NVP-BEZ235也能够诱导产生自噬,与Atg5的siRNA或自噬抑制剂3-甲基腺嘌呤(3-MA)联合应用时,肝癌细胞的生长被抑制.结论 NVP-BEZ235与Atg5的siRNA或者3-MA的联合应用能够促进细胞凋亡,NVP-BEZ235和自噬抑制剂的联合应用可为肝癌和其他恶性肿瘤临床治疗提供新的方法.     

Novel Ag nanocrystals based dental resin composites with enhanced mechanical and antibac terial propert ies

The aim of this work was to investigate the effect of trace addition of oleic acid coated Ag nanocrystals(Ag NCs) on mechanical and antibacterial properties of dental resin composites.Composites(70 wt%of silica loading) with 25 ppm,50 ppm,75 ppm and 100 ppm(wt) Ag NCs were prepared and the composite without Ag NCs served as a control.The experimental results showed that the addition of Ag NCs significantly improved the strength and modulus of the resin composite without compromising the shade.For the composite with 50 ppm Ag NCs,fiexural strength(140.3 MPa),modulus(13.2 GPa)and compressive strength(347.2 MPa) were increased by 4.1%,22.2%,13.3%,respectively,compared with the control.The antibacterial test demonstrated that trace Ag NCs provided the resin composites with an antibacterial effect.Such strong and antibacterial dental resin composites might be advantageous to prevent secondary caries and be potential for future clinical applications.     

生物炭的稳定性及其评价方法

围绕生物炭稳定性概念,论述了其影响因素,并对比分析生物炭稳定性的研究方法及预测模型。结果表明,生物炭稳定性的基础是其具有高度芳香化结构和土壤团聚体的保护作用,温度、原料及环境条件是影响生物炭稳定性的主要因素,生物炭稳定性最优评估方法为同位素标记法和双指数模型相结合,但其仍具有一定的局限性。在此基础上,指出不同土壤类型、轮作方式及预测模型是当前生物炭稳定性研究的前沿领域和深化方向。     

城市道路交通产生的振动对环境的影响

在对上海漕宝路道路交通产生的地面振动测试的基础上,分析了城市道路交通所产生的地面振动的传播规律,对城市交通振动对周围环境的影响进行了初步评价,影响地面振动的主要因素包括车辆的运行速度、载荷以及距道路中心的距离。     

Hydrogen bonding at the water surface revealed by isotopic dilution spectroscopy

The air-water interface is perhaps the most common liquid interface. It covers more than 70 per cent of the Earth's surface and strongly affects atmospheric, aerosol and environmental chemistry. The air-water interface has also attracted much interest as a model system that allows rigorous tests of theory, with one fundamental question being just how thin it is. Theoretical studies have suggested a surprisingly short 'healing length' of about 3??ngstr?ms (1?? = 0.1?nm), with the bulk-phase properties of water recovered within the top few monolayers. However, direct experimental evidence has been elusive owing to the difficulty of depth-profiling the liquid surface on the ?ngstr?m scale. Most physical, chemical and biological properties of water, such as viscosity, solvation, wetting and the hydrophobic effect, are determined by its hydrogen-bond network. This can be probed by observing the lineshape of the OH-stretch mode, the frequency shift of which is related to the hydrogen-bond strength. Here we report a combined experimental and theoretical study of the air-water interface using surface-selective heterodyne-detected vibrational sum frequency spectroscopy to focus on the 'free OD' transition found only in the topmost water layer. By using deuterated water and isotopic dilution to reveal the vibrational coupling mechanism, we find that the free OD stretch is affected only by intramolecular coupling to the stretching of the other OD group on the same molecule. The other OD stretch frequency indicates the strength of one of the first hydrogen bonds encountered at the surface; this is the donor hydrogen bond of the water molecule straddling the interface, which we find to be only slightly weaker than bulk-phase water hydrogen bonds. We infer from this observation a remarkably fast onset of bulk-phase behaviour on crossing from the air into the water phase.     

鲜枣中糖精的快速、无标签检测

糖精是食品工业中最古老的人造甜味剂之一,因为没有卡路里而被广泛使用,但其滥用是非法的,食品中最大允许添加量为8.189×10^-4mol·L^-1.介绍了以六磷酸肌醇（IP₆）为保护剂合成的银（Ag）纳米粒子（Ag NPs）,即Ag NPs@IP₆,并提出了一种基于表面增强拉曼散射（SERS）的快速方法.探讨了食品中糖精的测定,用最佳SERS法测定水中糖精的最低可检测浓度可达50 nmol·L^-1,符合食品添加剂耐受性水平的国家食品安全标准.提出了基于便携式拉曼的AgNPs@IP₆的SERS方法,可用于现场检测食品中的糖精,如新鲜枣果.     

Ag/TiO2光催化剂的表面性能表征

采用光催化还原法将 Ag沉积于 Ti O2 膜表面制备出负载型 Ag/Ti O2 光催化剂 ,通过 SEM、EDS检测出 Ti O2 表面上 A g元素的存在 ,由 TEM显示 Ag颗粒分散的均匀性 ,XPS图谱证实了 Ag是按光催化还原反应机理以单质形式存在 ,对低浓度甲基橙溶液光催化降解结果表明 ,沉积的单质 Ag对 Ti O2 光催化剂的降解活性有很大的提高作用。     

一价金属Ag、Au同步辐射光激发下的室温和低温光电子能谱分析

文章的实验采用同步辐射光源的能量范围60-200eV,分别测定单晶Ag的3d、4p、4d和5s电子以及研究其能带和谱峰的性质,分析给出Ag的光电子能谱的半高峰值的宽度。分析Ag在室温和低温下光电子能谱产生差异,以及低温下Ag的光电子能谱的性质。最终比较得出Ag、Au各个价带产生的光电子能谱谱峰中单色性最好的谱峰。计算出Ag导带的宽度与实验值进行比较。     

排水性沥青混合料强度影响因素分析

为了提高排水性沥青混合料的强度,采用马歇尔稳定度评价了6.7mm筛孔通过率、空隙率、纤维添加剂以及胶结料对排水性沥青混合料强度的影响,并采用劈裂强度和抗压强度进一步评价胶结料类型和目标空隙率对其强度的影响.研究表明,沥青的各指标中复数粘度η*与排水性沥青混合料60℃马歇尔稳定度有很好的相关性,沥青粘韧性与排水性沥青混合料的抗压强度和劈裂强度有很好的相关性,降低排水性沥青混合料的目标空隙率可以明显提高其强度性能,纤维添加剂及6.7mm筛孔通过率对排水性沥青混合料的强度影响很小.     

Ag@Pt核壳结构纳米粒子催化剂在电催化过程中的失效分析

通过种子生长法和自组装技术合成Ag@Pt核壳结构纳米粒子(以下简称Ag@Pt粒子),测量和比较在电催化循环伏安扫描(以下简称CV扫描)过程中失效前后的Ag@Pt粒子对甲醇的电催化性能的变化,采用透射电镜、高分辨电镜、X射线光电子能谱等方法研究其失效机理.结果表明：Ag@Pt粒子在循环伏安扫描的过程中会发生空化现象,其临界电压为0.5 V,空化现象随时间的增长而变得明显;Ag@Pt粒子空化后形成由Ag包覆空心Pt壳的纳米粒子,这是导致其在对甲醇进行电催化氧化过程中催化性能明显下降的原因.     

多重影响因素下的边坡稳定性评价方法及应用

 在边坡稳定性评价方法基础上,分析了边坡稳定性评价方法的某些缺陷,讨论了影响边坡稳定性的因素,并对影响边坡稳定性的几类指标进行分析和归类.从地质条件、自然环境、工程设计等角度考虑,建立了一种考虑多重影响因素并结合层次分析法(AHP)和模糊数学的边坡稳定性评价方法,利用该方法对某露天矿山边坡进行了稳定性评价.新分级体系下的边坡稳定性分级结果表明,中区和南区下盘边坡是潜在不稳定区域,需要进一步分析,而上盘边坡的稳定性明显好于下盘边坡的稳定性,这与CSMR的分级结果相近,验证了指标分类的合理性以及该评价方法的可行性.     

Ag表面对聚乙烯吡咯烷酮的吸附及纳米结构表面选择机制

为了查明Ag纳米线的选择形成机制以及与表面活性剂之间的相互作用，本文采用了基于密度泛函理论的第一性原理方法研究了不同Ag晶面结构在聚乙烯吡咯烷酮(PVP)体系中稳定性及吸附影响.结果表明：PVP分子体系严重影响不同Ag晶面结构的稳定性，对Ag(200)和Ag(111)晶面结构具有选择性.此外，随着PVP分子聚合度的增加，PVP与Ag(200)晶面的结合比Ag(111)更强，这有助于Ag(200)纳米结构的形成.本文从分子和原子的角度查明了长链PVP分子对Ag纳米结构的调控机制主要受PVP分子中的酮基氧与表面Ag原子之间的成键作用，以及PVP与Ag(200)表面之间的范德华力的影响.     

Mechanism of Ag and Al on improving the glass forming ability of CuZr-based alloys

By a mean field theoretical computation,the equilibrium distributions of additional Ag and Al in the crystalline phase of CuZr-based alloys were determined to occupy the two sublattices of the B2 structure randomly.With the molecular dynamics technique,the effects of Ag and Al on the enthalpy difference(ΔH) between the supercooled melt and the crystalline phase were evaluated.The improved glass forming ability of Cu45Zr45Al10 and Cu45Zr45Ag10 can be attributed to their remarkably smaller ΔH than that of CuZr.The calculated diffusion coefficients are more sensitive to the atomic weight of the component atoms than to their interaction strength.As the component atom with the largest mass,the additional Ag increases the viscosity of the supercooled melt significantly and the experimentally stronger glass formation ability of Cu45Zr45Ag10 than Cu45Zr45Al10 can be well understood.     

采出污水配制聚合物溶液的影响因素研究

研究了聚合物驱采出污水中Na+、K+、Ca2+、Mg2+、Fe2+、Fe3+六种离子对聚合物溶液初始黏度的影响和溶解氧、阳离子、粘土矿物以及细菌对其稳定性的影响程度,提出了采出污水配注聚合物的参考控制指标和限度。研究结果表明,高价金属阳离子是影响聚合物水溶液初始黏度的主要因素,其由大到小的顺序为Fe2+＞Fe3+＞Mg2+＞Ca2+＞Na+＞K+。配制用水的基本要求是不含铁离子,Ca2+离子含量控制在200mg/L以下,最好控制在50mg/L以下;Mg2+离子含量控制在100mg/L以下,最好控制在30mg/L以下;Na+、K+离子含量应该控制在2000mg/L以下,最好控制在500mg/L以下。高价金属离子和溶解氧是影响聚合物溶液黏度稳定性的主要因素,其由大到小的顺序为：Fe2+>Mg2+(Ca2+)>Fe3+>Na+(K+),一价阳离子和悬浮物对聚合物溶液黏度稳定性也有一定影响,细菌对其影响相对较小。     

硅胶基衬底表面高分辨复杂可延展电路的印刷制备

 柔性可延展电子因其能够适应非平面工作环境,将突破现有电子器件的应用范围,促进信息与人的融合,在智能穿戴电子、柔性显示、生物医疗等领域具有广阔的应用前景。本文提出利用印刷结合真空抽滤方法实现硅胶基衬底表面高分辨复杂可延展电路的制备;研究了丝网印刷工艺实现微孔滤膜表面银纳米线（Ag NWs）图形化沉积的分辨率;讨论了Ag NWs线长、抽滤真空度等因素对沉积分辨率的影响,实现了Ag NWs图形化50 μm线径分辨率及间隔分辨率。本文还研究了硅胶基衬底表面微电极的电阻均一性及拉伸电阻稳定性,并结合电极表面微结构的变化详细讨论了屈曲褶皱结构的出现对微电极拉伸电阻的影响,实现了100 μm线宽微电极100%拉伸幅度下电阻增加仅为初始值的40%。最后,通过集成LED芯片演示了面料基底表面柔性可延展发光电路。本研究对于柔性可延展电路的制备提供了新的思路。