基于数字化实验的原电池能量转化效率研究

采用数字化实验系统,对锌铜原电池中能量转化的定量研究,得出在单液锌铜原电池放电过程中,由于锌片与硫酸铜溶液接触,锌片与硫酸铜直接发生置换反应,化学能较多地转化为热能,能量转化效率不高,电流衰减,无法长时间稳定供电,实际应用受到限制。在双液锌铜原电池放电过程中,由于双液电池是一种可逆体系,化学能主要转化为电能,能量转化效率较高,因此,双液原电池受到广泛应用。     

利用手持技术探究铜锌双液原电池中电解质溶液对电流的影响

利用手持技术探究了铜锌双液原电池中电解质溶液的浓度和种类对电流的影响。得出正、负极电解质溶液的浓度与原电池的电流在一定范围内呈正相关，浓度越大，电流越大，负极电解质溶液种类的改变对原电池的电流影响有限。     

“原电池的工作原理”教学设计及课堂实录

对“原电池的工作原理”进行了教材分析、学情分析,在必修2学习的基础上,结合生活实际设计了4个教学环节：通过生活中的原电池和必修知识的复习,引出原电池原理;通过铜锌原电池的设计、分析,掌握单液原电池原理;从原电池的能量转化效率出发,学习双液原电池原理;利用原电池的形成条件,设计原电池。     

手持技术数字化实验探究夹心式膜电池的创新改进*

借助手持技术,用阳离子交换膜代替盐桥,滤纸代替烧杯,将双液铜锌原电池改进为高效化、微型化的夹心式阳离子交换膜原电池。通过实验探究、微观分析得出阳膜电池具有电流示数大且较稳定、装置简易、操作方便、药品用量小、绿色无污染等优点。本实验不仅揭示膜电池的工作原理、还原高考膜电池实验、构建化学电源的基本模型,还贴近生活,提高学生的自主实验探究能力,培养学生宏观辨识与微观探析、科学探究与创新意识的核心素养。     

从定量的角度探究单液铜锌原电池实验的改进方案

对铜-锌原电池中的锌片做半汞齐化处理,分别将锌片汞齐化的一端和非汞齐化的一端插入稀硫酸中,测量电池的电流和电压。通过2次实验的测量对照计算得出电流、电压损失百分比,从而定量地描述锌片上产生的氢气,并将此方法应用于改进单液原电池实验。从锌电极、铜电极和稀硫酸浓度3个方面采取改进措施,从而尽可能减少锌片上的气泡。     

基于热成像的单液与双液原电池性能比较实验

采用控制变量法和组合法设计了单液、双液原电池装置,借助红外热成像仪捕捉原电池发热部位的关键证据。实验表明,在其他条件相同的情况下,双液原电池的最大输出电流、放电效率和电流稳定性的性能均优于单液原电池。通过热成像仪获得的热图像和精确测温揭示了2种原电池性能差异的主要原因：单液原电池的负极有副反应,双液原电池的内阻较小。     

利用手持技术数字化实验促进学生原电池概念认知*——ZnCu稀硫酸原电池与Zn和稀硫酸反应的比较

以ZnCu稀硫酸原电池与Zn和稀硫酸反应的比较实验为例,探讨根据TQVC概念认知模型,设计促进学生原电池概念认知的手持技术数字化实验。具体过程是:将原电池概念关键内涵转化为可测量的温度和电流概念的关联属性,利用温度传感器和电流传感器测量实验的热能和电能的变化,通过实验数据、曲线及其四重表征分析得到实验结论,并判断实验设计的有效性。对实验设计的关键和实验证据的使用进行了讨论。     

促进学生学科能力发展的高一原电池教学关键策略

通过梳理电化学的有关研究，在已有的电化学认识模型研究的基础之上，结合高一原电池的具体知识和活动经验，构建了高一原电池的教学模型和表现指标，并开发前、后测试工具。以单液原电池、氢氧燃料电池、双液原电池等3种典型的教学原型为例，从情境素材的选取、教学活动的设计和教学对话的调整等3个维度来分析不同教学设计的异同点，并概括出高一原电池认识模型建立的有效教学策略。     

基于模型认知与手持技术的化学能与电能项目式教学*——以“设计不同类型的化学电源”为例

以“设计不同类型的化学电源”为项目主题,详细介绍了项目的确立、规划、实施。系列学习活动包括:原电池基础知识教学,建构与应用原电池认知模型,分组设计不同类型的化学电源,进行电流影响因素的探究实验,运用手持技术数字化实验测量电池电流大小,开展成果交流汇报等。课题源于生活,有助于学生深入理解化学能与电能之间的相互转化,提升化学兴趣,发展化学核心素养。     

铜锌原电池演示实验装置改进

对铜锌原电池实验所用装置进行了改进,避免了原电池实验中盐桥制作的烦琐和应用不便,提高了实验的可操作性和实验效率。     

A method for the detection of alcohol vapours based on optical sensing of magnesium 5,10,15,20-tetraphenyl porphyrin thin film by an optical spectrometer and principal component analysis

In this work we have proposed a method for the detection of alcohol vapours, i.e. methanol, ethanol and isopropanol, based on the optical sensing response of magnesium 5,10,15,20-tetraphenyl porphyrin (MgTPP) thin films, as measured by optical spectrometry with the assistance of chemometric analysis. We have implemented a scheme which allows a laboratory UV–vis spectrometer to act as a so-called “electronic nose” with very little modification. MgTPP thin films were prepared by a spin coating technique, using chloroform as the solvent, and then subjected to thermal annealing at 280 °C in an argon atmosphere. These MgTPP optical gas sensors presented significant responses with methanol compared to ethanol and isopropanol, based on the dynamic flow of alcohol vapours at the same mol% of alcohol concentration. Density functional theory (DFT) calculations were performed to model the underlying mechanism of this selectivity. The performance of the optical gas sensors was optimised by varying the fabrication parameters. It is hoped that the MgTPP thin film together with an off-the-shelf optical spectrometer and a simple chemometrics algorithm can be a valuable tool for the analysis of alcoholic content in the beverage industry.     

Optical sensor for hydrogen peroxide

Three types of sensors for continuous determination of hydrogen peroxide (HP) are described. The working principles are based on the decomposition of HP by a catalyst and on the measurement of the amount of oxygen thereby produced. The change in oxygen tension is quantitatively determined via the quenching of the fluorescence of a silica gel-adsorbed dye entrapped in silicone rubber. Three methods were found to be useful for HP decomposition. In the first one, the enzyme catalase (which acts as the catalyst) is co-adsorbed onto silica gel and thus is in the same phase as the indicator. In the second one, the enzyme and the dye are adsorbed on different silica gel particles which then are incorporated into the polymer layer. In the third one, finely dispersed silver powder (another catalyst) is embedded in a silicone rubber layer that is spread over the oxygen sensing membrane. The sensor is capable of continuously recording HP in the 0.1 to 10.0 mM concentration range, with a precision of ±0.1 mM at 1 mM HP. Its response time varies from 2.5 to 5 min.     

A Dual Colorimetric and Fluorometric Sensor for Lead Ion Based on Conjugated Polydiacetylenes

A PDA based sensor, derived from a di‐(2‐picolyl) amine (DPA) substituted diacetylene monomer, displayed a selective colorimetric change and a large fluorescence enhancement in the presence of lead ions. The lead selective PDA‐based chemosensor enabled easy detection of the presence of lead in 100% aqueous solution by the naked‐eye.

     

Optical Chemical Sensors Based on Sol-Gel Materials: Recent Advances and Critical Issues

The use of the sol-gel process to produce materials for optical chemical sensors and biosensors is attracting considerable interest. This interest derives mainly from the design flexibility of the sol-gel process and the ease of fabrication. In most applications the sol-gel material is used to provide a microporous support matrix in which analyte-sensitive species are entrapped and into which smaller analyte molecules may diffuse. Sensors based on entrapped organic and inorganic dyes, enzymes and other biomolecules have been reported. A range of sensor configurations has been employed, including monoliths, thin films, as well as more elaborate structures. In this paper a selection is presented of recent significant developments in optical chemical sensors which employ solgel-derived materials. These developments include the tailoring of sol-gel materials to optimise sensor response, advanced waveguide structures and novel probe-tip sensors. Those issues which remain critical to the eventual deployment of sol-gel sensors are examined. In particular, the problems of leaching, microstructural stability, diffusion-limited response time, and susceptibility to interferents are discussed and some solutions proposed.     

A new sensing material for optical oxygen measurement,with the indicator embedded in an aqueous phase

A new type of oxygen-sensitive material is obtained by preparing an aqueous emulsion of a solution of an oxygen-sensitive fluorescent dye in a rigid polymer. The fluorescence of this emulsion is related to the oxygen partial pressure, but a Stern-Volmer plot is not linear over the whole pressure range. Aside from high sensitivity and specificity for oxygen, this new type of sensing material has favorable analytical wavelengths allowing the use of low-cost opto-electronic equipment. Since the indicator is embedded in an aqueous environment, the sensor should be capable of monitoring various kinds of reactions occurring in the aqueous phase, for instance enzymatic reactions which are accompanied by production or consumption of oxygen.     

Chemical sensors (review)

The capabilities and development prospects of chemical sensors as a new area in analytical chemistry and instrument engineering are discussed. Problems of terminology, principles of operation, basic characteristics, and also applications of chemical sensors and sensor analyzers made from them are discussed.From the materials of a report given at a joint scientific session of the departments of the physicochemistry and technology of inorganic materials and of general and technical chemistry.V. I. Vernadskii Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, Moscow 117975. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 3, pp. 487–493, March, 1992.     

MOFs传感器在癌症及其生物标志物检测中的应用

癌症是世界上最致命的疾病之一,因此癌细胞的有效捕获和敏感检测对基础研究以及临床诊断和治疗都具有重要意义。基于金属有机骨架(MOFs)的催化活性和固有的发光性能等特点,MOFs已被成功地开发为传感平台实现对癌症及其标志物的检测。综述了基于MOFs的电化学、荧光、电化学发光、比色传感器在癌细胞及核酸、蛋白质等生物标志物检测中近3年的研究进展,从MOFs材料,检测物类型,检测方法、检测能力等方面进行了综述,并对各自的特点进行了讨论,对以后MOFs纳米材料在癌症检测中的应用进行了展望。     

Nitrogen‐doped Hollow Co3O4 Nanofibers for both Solid‐state pH Sensing and Improved Non‐enzymatic Glucose Sensing

Nitrogen‐doped hollow cobalt oxide nanofibers (Co₃O₄ NFs) with both glucose catalytic activity and pH sensitivity were fabricated through core‐sheath electrospinning technique, followed by calcination. The as‐developed nitrogen‐doped hollow Co₃O₄ NFs were thoroughly characterized using various techniques, and then employed to fabricate a dual electrochemical sensor for both pH sensing and glucose sensing. The pH sensitivity of the developed nitrogen‐doped hollow Co₃O₄ NFs demonstrated a Nernst constant of 12.9–15.9 mV/pH in the pH range of 3.0～9.0 and 6.8–10.7 mV/pH in the pH range of 9.0～13.0, respectively. The developed hollow cobalt oxides nanofibers sensor also possesses glucose sensitivity of 87.67 μA mM^?1 cm^?2, the limit of detection of 0.38 μM (S/N=3), and an acceptable selectivity against several common interferents in non‐enzymatic glucose determination. High accuracy for monitoring glucose in human serum sample was also demonstrated. These features indicate that the as‐synthesized nitrogen‐doped hollow cobalt oxides nanofibers hold great potential in the development of a unique dual sensor for both solid‐state pH sensing and superior non‐enzymatic glucose sensing.     

催化发光的应用研究进展

催化发光是物质在催化材料表面发生反应产生的发光现象,是一种重要的化学分析方法,在药物分析、食品分析、免疫学分析以及环境监测等方面具有广泛的应用前景。 本文从挥发性有机物的快速定量检测,分析物的识别区分以及催化剂的活性评估三方面综述了催化发光的应用研究进展,并对催化发光的研究方向进行了展望。     

A Multistep Enzyme Sensor for Sucrose Based on S-Layer Microparticles As Immobilization Matrix

Abstract

In this paper we report on the construction principle and performance of an amperometric 3-enzyme sensor for sucrose based on crystalline bacterial cell surface layers (S-layers) as immobilization matrix for the biological components.

Isoporous, crystalline surface layers (S-layers) have been identified as outermost cell envelope layer in many bacteria. Since they are composed of identical protein or glycoprotein subunits with functional groups in well defined positions and orientations, they represent ideal matrices for the controlled and reproducible immobilization of functional macromolecules, as required for the development of biosensors. Apart from single enzyme sensors, which were described earlier, a strikingly simple method for the assembly and optimization of multistep systems was developed. For the fabrication of an amperometric sucrose sensor invertase, mutarotase and glucose oxidase were individually immobilized on S-layer fragments isolated from Clostridium thermohydrosulfuricum L111-69 via aspartic acid as spacer molecules. Subsequently, appropriate mixtures of enzyme loaded S-layer fragments were deposited on a microfiltration membrane and finally, the composite multifunctional sensing layer was sputtered with gold in order to establish a good metal contact. Amperometric sucrose measurements based on H₂O₂ oxidation revealed a high signal level (1 μA^?1/cm^2?mmol sucrose), 5 min response time and a linear range up to 30 mM sucrose as the main characteristics of the S-layer sucrose sensor.