光量热法初探甲基橙光催化原位降解过程

通过在室温下还原前驱体制备了Ag@AgCl催化剂, 并利用X射线粉末衍射仪(XRD)和场发射扫描电子显微镜(FE-SEM)对产物进行表征. 设计了新型光化学-微热量系统, 用该系统获得了Ag@AgCl光催化降解甲基橙实时、 在线的热力学和动力学瞬态信息. 研究结果表明, 该降解过程首先经历吸热再迅速进入放热阶段, 最后曲线恒定于一个长的放热平台, 计算得到ab, ac和ad段的热效应分别为-0.2609, 2.5845和40.7289 J, 放热平台cd的平均速率为2.581 mJ/s, 并详细探讨了该过程的微观降解机制.     

基于溶胶-凝胶固定技术的生物组织传感器

报道了一个制备生物组织传感器的新技术。将溶胶 凝胶与植物液汁按一定比例结合 ,使天然植物中的多酚氧化酶被固定于溶胶 凝胶中 ,将其滴涂于预先涂有一层Nafion膜的铂盘电极表面 ,构成带有Nafion 溶胶凝胶 植物液汁的复合修饰膜的生物传感器 ,用于测定神经递质多巴胺。采用循环伏安法和线性扫描伏安法考察了传感器的电化学特性 ,比较了不同植物品种及其不同部位组织的生物催化活性 ;研究了乙醇用量、水酯比、植物液汁用量等因素的影响 ;考察了Nafion膜的防干扰性能。采用差示脉冲伏安法对多巴胺进行定量分析 ,线性范围为 2× 10 -6～ 1× 10 -4mol/L ;检出限为 8.0× 10 -7mol/L。与传统的组织电极相比 ,本传感器具有一系列特点。     

Nafion-sulfonated organosilica composite membrane for all vanadium redox flow battery

A novel Nafion-sulfonated diphenyldimethoxysilane (N-sDDS) composite membrane is prepared and employed in vanadium redox flow battery (VRB). Ion exchange capacity, proton conductivity, water transport behavior, and the cell performances are characterized. Fourier transform-infrared and X-ray diffraction analysis indicate that the sulfonated diphenyldimethoxysilane (sDDS) particles are successfully introduced into the Nafion matrix. In VRB single cell test, the VRB with N-sDDS membrane exhibits nearly the same coulombic efficiency as the unmodified Nafion membrane, but higher voltage efficiency than that of the VRB with unmodified Nafion membrane. The VRB with N-sDDS composite membrane keeps a stable performance after 60 times charge–discharge test. In the self-discharge test, the VRB with the N-sDDS membrane presented a lower self-discharge rate than that of the VRB with Nafion membrane. All results show that the addition of s-DDS is a simple and efficient way to improve the conductivity of Nafion, and the composite membrane shows good potential use for VRB.     

毛细管电泳-高频电导法快速测定牡丹皮中的丹皮酚

毛细管电泳—电化学检测的装置简便、价廉、灵敏度高,其中非接触式检测(电极不与溶液直接接触)避免了分离电场对检测的干扰和电极中毒,可广泛用于荷电成分的检测。本文采用本课题组建立的毛细管电泳—非接触高频电导法分析了牡丹皮中的丹皮酚,结果令人满意。     

阿霉素的吸附伏安法研究

阿霉素在０．１ｍｏｌ／Ｌ ＨＡｃ－ＮａＡｃ底液，富集电位－０．２０Ｖ，富集时间１２０ｓ，扫速１００ｍＶ／ｓ等条件下，于悬汞电极上产生一灵敏的吸附伏安还原峰，峰电位为－０．４５ＢＶ，峰电流与ＡＤＭ浓度为１．０×１０１０＾－９－４．０×１０＾－７ｍｏｌ／Ｌ范围内呈线性关系，检测限可达５．０×１０＾－１０ｍｏｌ／Ｌ。     

Glutathione‐Mediated Degradation of Surface‐Capped MnO2 for Drug Release from Mesoporous Silica Nanoparticles to Cancer Cells

Owing to its higher concentration in cancer cells than that in the corresponding normal cells, glutathione (GSH) provides an effective and flexible mechanism to design drug delivery systems. Here a novel GSH‐responsive mesoporous silica nanoparticle (MSN) is reported for controlled drug release. In this system, manganese dioxide (MnO₂) nanostructure, formed by the reduction of KMnO₄ on the surface of carboxyl‐functionalized MSN can block the pores (MSN@MnO₂). By a redox reaction, the capped MnO₂ nanostructure can dissociate into Mn²⁺ in the presence of GSH molecules. The blocked pores are then uncapped, which result in the release of the entrapped drugs. As a proof‐of‐concept, doxorubicin (DOX) as model drug is loaded into MSN@MnO₂. DOX‐loaded MSN@MnO₂ shows an obvious drug release in 10 × 10^?3 m GSH, while no release is observed in the absence of GSH. In vitro studies using human hepatocellular liver carcinoma cell line (HepG2) prove that the DOX‐loaded MSN@MnO₂ can entry into HepG2 cells and efficiently release the loaded DOX, leading to higher cytotoxicity than to that of human normal liver cells (L02). It is believed that further developments of this GSH‐responsive drug delivery system will lead to a new generation of nanodevices for intracellular controlled delivery.     

一种基于碳纳米管的安培型过氧化氢生物传感器

利用硫堇(th ion ine,Th i)作为介体结合多壁碳纳米管(MWNTs)、壳聚糖(ch itosan,CH IT)、辣根过氧化酶(HRP)的混合包埋物制作过氧化氢(H2O2)生物传感器。研究结果表明所得传感器对H2O2具有明显的增敏效应,线性范围为0.03~5.5 mmol/L,相关系数为0.9995;检出限为19μmol/L(S/N=3),具有良好的稳定性及工作寿命。     

Critical temperature of Bose-Einstein condensation for weakly interacting bose gas in a potential trap

It has been a long history to study Bose-Einstein condensation (BEC) of weakly in-teracting Bose gas, and several theoretical models have been developed to research uni-form and weakly interacting Bose gas. Ref. [1] summarized all of these models and the corresponding results, which gave a derivation of critical temperature from ideal case 1/30Tc c n,?T = α (1) with a wide spread of parameter c from 0.7 to 2.33, where α is the scattering length of s wave and n is atom number density. Due…     

g-C_3N_4@Ag_3PO_4光催化降解罗丹明B过程的原位光-微热量-荧光光谱研究

采用光-微热量-荧光光谱联用系统获取了g-C_3N_4@Ag_3PO_4光降解罗丹明B(RhB)的原位热/动力学信息和三维荧光光谱信息,并结合热力学和光谱学结果探究了光催化降解罗丹明B的微观机制.结果表明,光催化降解过程主要分为表观吸热、热平衡以及稳定放热3个阶段.在g-C_3N_4@Ag_3PO_4存在下,可见光照射10 min后,罗丹明B的三维荧光特征发射峰强度降低至初始值的7.1%,罗丹明B的降解脱色率达92.9%,是相同条件下以纯g-C_3N_4为催化剂时的2.06倍.随着光照时间的延长,光-微热量计显示10 min后以降解及矿化非荧光中间产物为主,并保持热焓变化率为-(0.226±0.0916)mJ/s稳定放热,为拟零级反应过程,并且该阶段为光催化反应的决速步骤.