Electrochemical detection of cell concentration based on reaction of DNA with molybdate

This article describes a fast and simple electrochemical assay for detecting cell concentration.After cell death,the membrane of cells will be broken,and DNA molecules contained in the cells will be released,but this does not happen in living cells.Sodium molybdate can react with the phosphate backbone of the released DNA molecules to form phosphomolybdate precipitation and produces a corresponding redox current.The higher the concentration of DNA,the stronger the intensity of the current generated.Sodium molybdate solution and centrifuged cell supernatant were added onto the glassy carbon electrode to determine the cell concentration by measuring the current intensity.The cell viability,which means the ratio of living cells to the total cells,can also be determined by this method.This assay has the advantages of high sensitivity,low detection limit,and wide detection range.In addition,this method was successfully applied to the detection of cell concentration in human serum,which has potential clinical applications.     

基于电-化-热耦合理论对称双阴极固体氧化物燃料电池堆的电流与温度场数值模拟

本文基于电-化-热多场耦合理论,通过有限元方法建立了一个基于对称双阴极结构SOFC电堆单元的三维数值模型,研究了其电堆内部的电流密度分布和温度分布. 研究结果表明,气体流动方式以及集流方式影响了电解质上电流密度和温度分布：在气体进、出气口处有较大的电流密度分布;在气体共流模式下,电解质层温度分布却较均匀;在双阴极结构电池阴极侧的单一集流模式下,集流侧的电解质的平均电流密度高于另一侧.     

一种用于测定高氯酸盐电流效率的气体分析方法及其应用

吭氯酸盐电解电流效率的化学分析过程复杂、费时。本文通过改变电解槽结构,提出一种气体分析方法,即采用氧阴极或使用一张钠离子交换膜改变电极槽结构,通过测定电解槽产气量,得到电解电流效率。与传统分析方法相比,气体分析方法既简单又方便。这种方法特别适用于实验室研究使用和评价阳极材料的电化学性能。此外,使用氧阴极代替铁阴极,可以电解电压和节约电能。     

电流反馈示波极谱滴定法

本文提出了电流反馈示波极谱滴定法的原理、仪器装置及操作技术。为了提高去极剂切口的灵敏度, 可将dE/dt信号转换为电流信号后再反馈回电解池以补偿充电电流,一般可将切口灵敏度提高1至5倍, 图形分辨率也较经典方法高, 从而使滴定终点的变化更为敏锐, 扩大了示波极谱滴定的应用范围, 推导了电流反馈的交流电流极化理论公式, 分析了电流反馈对示波极谱图形、去极剂切口灵敏度及切口电位的影响。     

A Membrane reactor for thionine-based solar cells

Short-lived reaction intermediates can be separated and prevented from reacting further by using a membrane reactor. This paper describes such a reactor for the thionine—ferrous iron solar cell. The theory and results show how the current produced by this solar cell can be increased     

Electrochemical Red Blood Cell Counting: One at a Time

We demonstrate that the concentration of a red blood cell solution under physiological conditions can be determined by electrochemical voltammetry. The magnitude of the oxygen reduction currents produced at an edge‐plane pyrolytic graphite electrode was diagnosed analytically at concentrations suitable for a point‐of‐care test device. The currents could be further enhanced when the solution of red blood cells was exposed to hydrogen peroxide. We show that the enhanced signal can be used to detect red blood cells at a single entity level. The method presented relies on the catalytic activity of red blood cells towards hydrogen peroxide and on surface‐induced haemolysis. Each single cell activity is expressed as current spikes decaying within a few seconds back to the background current. The frequency of such current spikes is proportional to the concentration of cells in solution.     

Electrolysis of ammonia for hydrogen production catalyzed by Pt and Pt-Ir deposited on nickel foam

Electrolysis of ammonia in alkaline electrolyte solution was applied for the production of hydrogen. Both Pt-loaded Ni foam and Pt-Ir loaded Ni foam electrodes were prepared by electrodeposition and served as anode and cathode in ammonia electrolytic cell, respectively. The electrochemical behaviors of ammonia in KOH solution were individually investigated via cyclic voltammetry on three electrodes, i.e. bare Ni foam electrode, Pt-loaded Ni foam electrode and Pt-Ir loaded Ni foam electrode. The morphology and composition of the prepared Ni foam electrode were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Effects of the concentration of electrolyte solution and temperature of electrolytic cell on the electrolysis reaction were examined in order to enhance the efficiency of ammonia electrolysis. The competition of ammonia electrolysis and water electrolysis in the same alkaline solution was firstly proposed to explain the changes of cell voltage with the electrolysis proceeding. At varying current densities, different cell voltages could be obtained from galvanostatic curves. The low cell voltage of 0.58 V, which is less than the practical electrolysis voltage of water (1.6 V), can be obtained at a current density of 2.5 mA/cm². Based on some experimental parameters, such as the applied current, the resulting cell voltage and output of hydrogen gas, the power consumption per gram of H₂ produced can be estimated.     

Automated mass analysis of low-molecular-mass bacterial proteome by liquid chromatography-electrospray ionization mass spectrometry

Due to the presence of a large number of proteins in cell extracts, ion chromatograms of cell extracts obtained by electrospray ionization mass spectrometry (ESI-MS) can be quite complicated. It is found that the elevated baseline in an ion chromatogram contains many protein signals. One deficiency of current commercially available LC-ESI-MS data interpretation software is found to be the lack of functional operation that allows automated mass spectral integration and interpretation over signals hidden in the baseline. This current limitation can be overcome by a technique that involves the introduction of artificial pulses to an ion chromatogram by removing the solvent mixer in the HPLC pump. These artificial pulses are treated as chromatographic peaks by the software, thereby allowing automated spectral integration over the duration of a pulse. The reliability of mass analysis from the integrated spectra is shown to be dependent on spectral interpretation parameters such as mass spectral baseline threshold. The application of this method is demonstrated for rapid detection and mass analysis of low-molecular-mass proteins from cell extracts of Escherichia coli or Bacillus globigii.     

Numerical modeling of a four-electrode electrochemical accelerometer based on natural convection: The boussinesq flow model vs. The compressible flow model

Two-dimensional numerical simulations are conducted to study the feasibility of applying the Boussinesq approximation to the steady-state buoyancy-driven flow in a four-electrode electrochemical accelerometer. Two kinds of electrode layouts along the electrochemical cell, the anode-cathode-cathode-anode (ACCA) and the cathode-anode-anode-cathode (CAAC), are examined. The results from the model based on the Boussinesq approximation are compared to those from the compressible flow model. Though the Boussinesq flow model leads to fairly large quantitative deviations, it is capable of qualitatively estimating the output electric current when the output electric current increases linearly as the applied axial acceleration. A qualitative difference between the two models are found in the centerline density profiles in the electrochemical cell, which can be explained by the compressibility-induced acceleration/deceleration. It is found that the Boussinesq approximation is good enough for the estimation of the electric current at a single electrode while can make large deviations of the cathodic current difference, i.e., the output electric current in this study.     

Chemometrics assisted resolving of net faradaic current contribution from total current in potential step and staircase cyclic voltammetry

Total current in the electroanalytical data is assumed to be consisting of three main constituents: faradaic current, step charging current and induced charging current. Both charging currents can cause an interfering effect on precise determination of faradaic currents, and hence insert direct effects on sensitivity and detection limit of the electroanalytical techniques. Despite the widespread techniques introduced until now, the extraction of the net faradaic current from total current still remains a challenge. In this work, by using multivariate curve resolution-alternating least square (MCR-ALS) as a powerful curve resolution-based chemometrics method, a straightforward method has been introduced for resolving faradaic current from the two types of charging currents (step charging current and induced charging current) in single potential step and staircase cyclic voltammetric methods. By simultaneous analyses of the current data matrices for different electrochemical systems, the three sources of current were successfully identified and their contributions in the total signal were easily calculated. Also, in this manner, the cell time constant can be obtained easily. Contrary to the previously reported methods, the present method does not need any pre-determined mathematical method; particularly there is no need to know the cell time constant.     

质子交换膜燃料电池新结构

质子交换膜燃料电池（ＰＥＭＦＣ）能量效率和功率密度高,无电解质腐蚀,环境友好,可望广泛用于电动汽车的发电装置、便携式电源和地面发电站等．许多发达国家都投巨资对其进行研究开发［１］．传统的单对ＰＥＭＦＣ由膜～电极组件和其两侧的集流板构成,其中膜～电极组...     

细胞表面壳化的研究进展

细胞表面壳化主要是通过物理、化学等技术方法对细胞表面进行修饰,形成完整均匀的有机、无机、金属纳米粒子或者复合壳层结构,从而使不能自身壳化的生物细胞表面形成保护壳甚至赋予细胞新的功能,使细胞具备多功能性。近年来,此技术在细胞存储、细胞运输、细胞传感器、细胞芯片以及细胞治疗等方面应用广泛,发展迅速。本文综合目前的研究现状,详细介绍了可进行细胞表面壳化的细胞类型、生物表面壳化的方法以及人造细胞外壳的工程技术在生物医学以及能源环境中的应用等。     

A Solar Cell That Is Triggered by Sun and Rain

All‐weather solar cells are promising in solving the energy crisis. A flexible solar cell is presented that is triggered by combining an electron‐enriched graphene electrode with a dye‐sensitized solar cell. The new solar cell can be excited by incident light on sunny days and raindrops on rainy days, yielding an optimal solar‐to‐electric conversion efficiency of 6.53 % under AM 1.5 irradiation and current over microamps as well as a voltage of hundreds of microvolts by simulated raindrops. The formation of π‐electron|cation electrical double‐layer pseudocapacitors at graphene/raindrop interface is contributable to current and voltage outputs at switchable charging–discharging process. The new concept can guide the design of advanced all‐weather solar cells.     

Electrooxidation of Hydroxypivalaldehyde in an Undivided Cell

IntroductionHydroxypivalaldehyde(HPAL)has two activefunctional groups,aldehyde and alcohol.The directelectrooxidation of alcohol or aldehyde has been repor-ted,such as the electrooxidations of croton aldehyde,benzaldehyde[1],and benzyl alcohol[2—4].Howev…     

Combined local current distribution measurements and high resolution neutron radiography of operating Direct Methanol Fuel Cells

The current and fluid distribution in Direct Methanol Fuel Cells (DMFCs) was investigated in situ by means of combined high resolution neutron radiography and locally resolved current distribution measurements. The used neutron radiography set-up allows high spatial resolutions down to 70 μm at the full test cell area. A local formation of water droplets in the cathode flow field channels could be observed. Strongly inhomogeneous current distributions during cathodic flooding processes result in a performance loss of up to 30% of the initial value. Single CO₂ bubbles can be observed at low current densities. The water and current distribution during bi-functional operation of a DMFC was measured for the first time.     

Attachment of bacterial cells to carbon electrodes

Anodic stripping method was applied to analyze the process of bacterial attachment to the surface of carbon-paste electrodes (CPE). The electrode was immersed for various times in a bacterial cell suspension to allow the cells to attach to its surface. The number of bacterial cells attached to the electrode surface increased along with time. On the other hand, the current derived from the oxidation of a dye, Hoechst, which was adsorbed to the surface after attaching the bacterial cells, decreased along with time. It was considered that the current output, correlated with the amount of dye, adsorbed onto regions where no bacterial cell attached. These results indicate that the bacterial-attachment process can be analyzed by measuring the electric current derived from the dye instead of counting the number of attached cells.     

涂碳铝箔对磷酸铁锂电池性能影响研究

本文研究了使用涂碳铝箔作为正极集流体磷酸铁锂电池的性能。研究对比了使用普通铝箔和涂层铝箔的10 Ah软包磷酸铁锂电池的主要性能。研究表明：使用涂层铝箔不但可以提高磷酸铁锂材料的粘结性,而且使用导电涂层可以有效降低正极材料和集流体的接触内阻,从而减小电池内阻,提高电池倍率性能。与使用普通铝箔作为集流体相比,通过使用涂碳铝箔可以使得电池的内阻降低65%左右,但是,磷酸铁锂正极材料的克容量却偏低约5~10 mAh·g^-1,首次效率也偏低4%左右;在快速放电15C倍率下,使用涂碳铝箔的电芯比使用普通铝箔容量提高约15%左右,10C放电倍率下,平台增加0.3~0.4 V;使用涂碳铝箔电芯的常温自放电率较高,但容量恢复率也较高;550周循环下,使用涂碳铝箔可以使得电池的循环性能提高约1%。而在电池低温性能方面,使用涂碳铝箔对低温性能并无改善。     

Optimization of electrolysis in the cylindrical electrochemical cell rotating in the magnetic field

The relationships between the rotational rate of electrochemical cell, its ohmic resistance, a ratio between the radii of inner and outer cylindrical electrodes, a sum of cathodic and anodic potentials, and the mechanical energy, which is consumed for passing a prescribed current and overcoming friction forces, are analyzed. It is shown that the relationships can be used to optimize the operation of rotating electrochemical cell.     

钠碱法烟气脱硫膜电解再生研究

通过中试实验，研究了钠碱法吸收SO2的过程及其不同条件下膜电解循环再生脱硫废液。结果表明，电流密度和吸收液浓度对再生效果影响较大，高电流密度时的中间室硫转化率高、电导率下降速率快，而低电流密度时的中间室电流效率则稍大；高电流密度时的阴极室pH值和电导率上升速率大于低电流密度时的上升速率，并在电解一定时间后上升速率突然加大。低浓度时中间室电流效率高、硫转化率大且电导率下降速率快；低浓度时阴极室pH值和电导率上升速率要大于高浓度时的上升速率，且在电解一定时间后上升速率突然加大。     

涂碳铝箔对磷酸铁锂电池性能影响研究

本文研究了使用涂碳铝箔作为正极集流体磷酸铁锂电池的性能。研究对比了使用普通铝箔和涂层铝箔的10 Ah软包磷酸铁锂电池的主要性能。研究表明:使用涂层铝箔不但可以提高磷酸铁锂材料的粘结性,而且使用导电涂层可以有效降低正极材料和集流体的接触内阻,从而减小电池内阻,提高电池倍率性能。与使用普通铝箔作为集流体相比,通过使用涂碳铝箔可以使得电池的内阻降低65%左右,但是,磷酸铁锂正极材料的克容量却偏低约5~10 mAh·g-1,首次效率也偏低4%左右;在快速放电15C倍率下,使用涂碳铝箔的电芯比使用普通铝箔容量提高约15%左右,10C放电倍率下,平台增加0.3~0.4 V;使用涂碳铝箔电芯的常温自放电率较高,但容量恢复率也较高;550周循环下,使用涂碳铝箔可以使得电池的循环性能提高约1%。而在电池低温性能方面,使用涂碳铝箔对低温性能并无改善。