Glassy carbon electrode modified with multi-walled carbon nanotubes sensor for the quantihication of antihistamine drug pheniramine in solubilized systems

A sensitive electroanalytical method for quantification of pheniramine in pharmaceutical formulation has been investigated on the basis of the enhanced electrochemical response at glassy carbon electrode modified with multi-walled carbon nanotubes in the presence of sodium lauryl sulfate.The experimental results suggest that the phcniramine in anionic surfactant solution exhibits electrocatalytic effect resulting in a marked enhancement of the peak current response.Peak current response is linearly dependent on the concentration of pheniramine in the range 200-1500 μg/mL with correlation coefficient 0.9987.The limit of detection is 58.31 μg/m L.The modified electrode shows good sensitivity and repeatability.

Numerical Study of Pulsed Dielectric Barrier Discharge at Atmospheric Pressure Under the Needle-Plate Electrode Configuration

In this paper, we study the characteristics of atmospheric-pressure pulsed dielectric barrier discharge （DBD） under the needle-plate electrode configuration using a one-dimensional self-consistent fluid model. The results show that, the DBDs driven by positive pulse, negative pulse and bipolar pulse possess different behaviors. Moreover, the two discharges appearing at the rising and the falling phases of per voltage pulse also have different discharge regimes. For the case of the positive pulse, the breakdown field is much lower than that of the negative pulse, and its propagation characteristic is different from the negative pulse DBD. When the DBD is driven by a bipolar pulse voltage, there exists the interaction between the positive and negative pulses, resulting in the decrease of the breakdown field of the negative pulse DBD and causing the change of the discharge behaviors. In addition, the effects of the discharge parameters on the behaviors of pulsed DBD in the needle-plate electrode configuration are also studied.

Influence of rapid quenching on cyclic stability of La-Mg-Ni system (AB_3-type) electrode alloys

Aiming at the improvement of the cyclic stability of La-Mg-Ni system （PuNi3-type） hydrogen storage alloy, Ni in the alloy was partly substituted by Fe. The electrode alloys of La0.7Mg0.3Co0.45Ni255-xFex （x=0, 0.1, 0.2, 0.3, 0.4） were prepared by casting and rapid quenching. The influence of the quenching on cyclic stability as well as structure of the alloys was investigated in detail. The results of electrochemical measurement indicated that rapid quenching significantly improved cyclic stability. When the quenching rate rose from 0 （As-cast was defined as a quenching rate of 0 m/s） to 30 m/s, the cyclic life of Fe-free alloy （x=-0） increased from 81 to 105 cycles, and for alloy containing Fe（x=0.4）, it grew from 106 to 166 cycles at a current density of 600 mA/g. The results obtained by XRD, TEM and SEM revealed that the as-cast and quenched alloys had multiphase structures, including two major phases （La, Mg）Ni3 and LaNi5 as well as an imptLrity phase LaNi2. Rapid quenching helped the formation of an amorphous-like structure in Fe containing alloys.

Effects of substituting Ni with M (M=Cu, Al and Mn) on microstructures and electrochemical characteristics of La-Mg-Ni system (PuNi_3-type) electrode alloys

In order to improve the electrochemical cycle stability of La-Mg-Ni system (PuNi3-type) hydrogen storage alloy, Ni in the alloys was partially substituted by M (M=Cu, Al, Mn). A new La-Mg-Ni system electrode alloys La0.7Mg0.3Ni2.55-xCo0.45Mx (M=Cu, Al, Mn; x=0, 0.1) were prepared by casting and rapid quenching. The effects of element substitution and rapid quenching on the microstructures and electrochemical performances of the alloys were investigated. The results by XRD, SEM and TEM show that the alloys have a multiphase structure, including the (La, Mg)Ni3 phase, the LaNi5 phase and the LaNi2 phase. The rapid quenching and element substitution have an imperceptible influence on the phase compositions of the alloys, but both change the phase abundance of the alloys. The rapid quenching significantly improves the composition homogeneity of the alloys and markedly decreases the grain size of the alloys. The Cu substitution promotes the formation of an amorphous phase in the as-quenched alloy, and a reversal result by the Al substitution. The electrochemical measurement indicates that the element substitution decreases the discharge capacity of the alloys, whereas it obviously improves the cycle stability of the alloys. The positive influence of element substitution on the cycle life of the alloys is in sequence Al>Cu>Mn, and negative influence on the discharge capacity is in sequence Al>Mn>Cu. The rapid quenching significantly enhances the cycle stability of the alloys, but it leads to a different extent decrease of the discharge capacity of the alloys.

The In-cell iR Compensation Using a Four-electrode System

A novel idea of in-cell iR compensation was proposed by using a four-electrode electrochemical system, which was consisted of two working electrodes, one reference electrode （RE） and one auxiliary electrode （AE）. One of the two working electrodes was called the auxiliary working electrode （AWE）, which was directly connected to the ground. Another working electrode was used as a regular working electrode （WE） for electrochemical testing. The reference electrode was set in a frit close to the AWE for potential sampling. The other electrodes, WE, RE and AE, were connected to a conventional potentiostat of three-electrode system for electrochemical measurements. A linear narrow electrochemical cell was designed for setting AE at one end and AWE with RE at another end, and setting WE in between AE and AWE. In this way, a positive feedback potential was generated at the working electrode from the solution resistance and the current flow in the solution. An formal iR compensation over 100%, as high as 500%, had been achieved without potential oscillation. The electrochemical cell design, the principle of the in-cell iR compensation, and the preliminary voltammetric characterization by using the redox reaction of ferrocyanide anions were reported.

Study on the Multi-Sensing System Based on the Tin Oxide pH Electrode

In this study,the multi-sensing system based on the tin oxide pH electrode for the ion-determination was presented. With the advantages of the real-time supervisory control apparatus,the measured values could be displayed on the liquid crystal display (LCD) immediately.In this study,the basic sensor was the tin oxide pH electrode,which was fabricated by radio frequency (r.f.) sputtering system on the indium tin oxide (ITO)/glass substrate.Moreover,the major blocks of the system consist of the tin oxide electrode-based ion selective electrodes (ISEs),an analog front-ended readout circuit,a microcontroller with built-in analog to digital (A/D) converter.In addition,by the embedded system design,the measurement results can be transmitted to a portable system or computer through the Universal Serial Bus (USB) and Universal Asynchronous Receiver Transmitter (UART) interface immediately.According to the experimental results,the multi-sensing system has high performance and reliability for pH,K^+,and Na^+ detection.

Development of an electrode intelligent design system based on adaptive fuzzy neural network and genetic algorithm

The coating on the electrodes contains many kinds of raw materials which affect significantly on the mechanical properties of deposited metals. It is still a problem how to predict and control the mechanical properties of deposited metals directly according to the components of coating on the electrodes. In this paper an electrode intelligent design system is developed by means of fuzzy neural network technology and genetic algorithm,, dynamic link library, object linking and embedding and multithreading. The front-end application and customer interface of the system is realized by using visual C ＋＋ program language and taking SQL Server 2000 as background database. It realizes series functions including automatic design of electrode formula, intelligent prediction of electrode properties, inquiry of electrode information, output of process report based on normalized template and electronic storage and search of relative files.

A Study on a Partially Immersed Gold Electrode Using an Electrochemical Quartz Crystal Impedance System

The electrochemical quartz crystal impedance system (EQCIS) has been used for the study of a partially immersed Au electrode in 0.2 mol/L NaClO4 aqueous solution. The influences of the immersed area and height of the electrode on the EQCIS responses were evaluated, showing the highest response sensitivity to liquid loading at the center of the piezoelectric quartz crystal electrode. The increase in the immersed height of the Au electrode at oxygen reduction potentials during potential cycling was measured by this technique.

Effects of rapid quenching on structure and electrochemical characteristics of La_(0.5)Ce_(0.2)Mg_(0.3)Co_(0.4)Ni_(2.6-x)Mn_x(x=0-0.4) electrode alloys

The La-Mg-Ni system PuNi3-type La0.5Ce0.2Mg0.3Co0.4Ni2.6-xMnx(x=0,0.1,0.2,0.3,0.4) hydrogen storage alloys were prepared by casting and rapid quenching. The effects of the rapid quenching on the structure and electrochemical characteristics of the alloys were studied. The results obtained by XRD,SEM and TEM indicate that the as-cast and quenched alloys mainly consist of two major phases,(La,Mg)Ni3 and LaNi5,as well as a residual phase LaNi. The rapid quenching does not exert an obvious influence on the phase composition of the alloys,but it leads to an increase of the LaNi5 phase and a decrease of the(La,Mg)Ni3 phase. The as-quenched alloys have a nano-crystalline structure,and the grain sizes of the alloys are in the range of 20-30 nm. The results by the electrochemical measurements indicate that both the discharge capacity and the high rate discharge(HRD) ability of the alloy first increase and then decrease with the variety of quenching rate and obtain the maximum values at the special quenching rate which is changeable with the variety of Mn content. The rapid quenching significantly improves the cycle stabilities of the alloys,but it slightly impairs the activation capabilities of the alloys.

Examining the Effects of Common Laboratory Methods on the Sensitivity of Carbon Fiber Electrodes in Amperometric Recordings of Dopamine

Carbon fiber microelectrodes (CFEs) are useful when combined with electrochemical techniques for measuring changes in neurotransmitter concentrations. We addressed conflicting details regarding the use of CFEs. Experimental groups consisted of CFEs at different ages (1 week, 1 month, or 2 months), cleaned in solvents (isopropanol or xylene), and exposed to in vitro use (flow cell calibrations) or in vivo use (in brain tissue). In order to determine if any of these factors affect CFE sensitivity, the present study utilized fixed potential amperometry and a flow injection system to calibrate CFEs for the measurement of dopamine. The sensitivity index (nA/μM per 100 μm of exposed carbon fiber) was not affected by the age of CFEs or pre-cleaning with xylene or isopropanol. CFE sensitivity of the in vitro exposure group also did not differ from untreated CFEs, indicating the calibration process did not alter sensitivity. However, in vivo use in brain tissue did reduce sensitivity. This effect was negated and sensitivity restored by cleaning CFEs in isopropanol or xylene following in vivo brain recordings. Given that variations in CFE sensitivity can skew results, our findings can help standardize CFE use and explain discrepancies between researchers.

Cycle Stabilities of La_(0.7)Mg_(0.3)Ni_(2.55-x)Co_(0.45)M_x (M=Fe, Cu, Al;x=0, 0.1) Electrode Alloys Prepared by Casting and Rapid Quenching

La-Mg-Ni system (PuNi3-type) hydrogen storage alloys La0.7Mg0.3Ni2.55-xCo0.45Mx (M=Fe, Cu, Al; x=0, 0.1) were prepared by casting and rapid quenching. Aiming to improve the cycle stabilities of the alloys, Ni in the alloy was partly substituted by Fe, Cu and Al. The effects of the substitution of Fe, Cu and Al for Ni and the rapid quenching on the microstructures and electrochemical properties of the alloys were investigated in detail. The results obtained by XRD, SEM and TEM indicate that the element substitution has no influence on the phase compositions of the alloys, but it changes the phase abundances of the alloys. Particularly, the substitution of Al and Cu obviously increases the amount of the LaNi2 phase. The substitution of Al and Fe leads to a great refinement of the as-quenched alloy′s grains. The substitution of Al strongly restrains the formation of the amorphous in the as-quenched alloy, but the substitution of Fe and Cu is quite helpful for the formation of an amorphous phase. The effects of the substitution of Fe, Cu and Al on the cycle stabilities of the as-cast and quenched alloys are different. The positive impact of the substitution elements on the cycle stabilities of the as-cast alloys is ranked in proper order Al>Fe>Cu, and for as-quenched alloys, the order is Fe>Al>Cu. Rapid quenching engenders an unconscious influence on the phase composition, but it markedly enhances the cycle stabilities of the alloys.

Novel Plasma Reactor with Rotary Helix Electrode Used in Coupling of CH_4 at Atmospheric Pressure

At the ambient temperature and pressure a glow discharge plasma was used as a new approach for the coupling of methane with the newly-developed rotary multidentate helix electrode. In the presence of hydrogen, the effects of the input peak voltages and gas flow rates on methane conversion, C2 single pass yield and selectivity were investigated, and then the results were compared with those from the three-disc multidentate electrode. This demonstrated, on an experimental scale, that the rotary multidentate helix electrode was better than the multidentate three-disc electrode as there was little accumulation of coke, and the C2 yield per pass was 69.85% and C2 selectivity over 99.14% with 70.46% methane conversion at an input peak voltage of 2300 V and 60 ml/min gas flow rate.

含铁纳米纤维电极去除水中孔雀石绿

作为一种典型的三苯甲烷类染料,孔雀石绿具有降解难度大、对生态环境和人类危害大等特点,因此水中孔雀石绿的治理问题不容忽视。本工作借助静电纺丝技术和液相还原法,将纳米铁颗粒物负载于高度蓬松的PVA纳米纤维,制备高性能的含铁纳米纤维,并利用其作为第三维电极构建三维电极反应体系,考察三维电极体系中孔雀石绿的去除行为。结果表明,未接通电源时含铁纳米纤维对水中孔雀石绿具有良好的吸附效果,吸附行为符合准二级动力学模型;在三维电极体系中,含铁纳米纤维先借助吸附作用对水中孔雀石绿进行富集浓缩,然后通过电解作用同时实现孔雀石绿的降解和含铁纳米纤维活性位点的再生。在预吸附-电解40 min后,水中孔雀石绿的去除率超过了95%,且反应体系呈现出较强的pH值耐受性。

丙泊酚对成年癫痫患者左侧大脑新皮质与边缘系统立体定向脑电图的影响

目的探究不同效应室浓度丙泊酚对成年癫痫患者左侧大脑新皮质与边缘系统立体定向脑电图(SEEG)的影响。方法选择2021年1月—2022年12月于我院癫痫外科行机器人立体定向辅助左侧颅内电极植入术后择期电极拔除的患者14例,根据植入电极位置将患者分为新皮质组和边缘系统组,记录并比较两组患者术中丙泊酚效应室浓度分别为0、2、3、4、5 mg/L(后简称D1~D5浓度)时SEEG的δ、θ、α、β、γ波各波段功率范围和功率百分比,以及δ-γ、θ-γ、α-γ、β-γ相位幅度耦合(PAC)的调制指数(MI)。结果D2~D5浓度时,边缘系统组和新皮质组患者立体定向脑电图γ波功率范围显著低于D1浓度时(F=15.13、20.33,t=4.33~8.72,P<0.05);D3浓度时,边缘系统组患者α波功率百分比显著高于D1、D2浓度时(F=23.38,t=5.52、9.38,P<0.05);D3~D5浓度时,边缘组患者θ-γ、α-γPAC MI均显著低于D1浓度时(F=13.64、18.77,t=7.62~17.68,P<0.05)。结论丙泊酚可以引发成年癫痫患者左侧大脑新皮质及边缘系统的SEEGγ波功率范围降低以及边缘系统SEEGθ-γ、α-γ的PAC降低。

电解极板高效烘干系统设计与应用

电解是金属提纯的主要方法,而电解锰在洗涤后、剥离前需要烘干,以避免锰在潮湿的环境下被氧化。目前,大多数生产企业在清洗和烘干过程中采用人工操作,劳动强度大,生产效率低,烘干能耗高。该文结合我国电解锰后处理装备发展的现状,通过对极板烘干机理的研究,提出将吹干与烘干结合,在电解极板洗涤后进入烘箱前增加风刀吹干,将极板表面水分预先吹落,再对极板进行烘干的高效烘干系统,该技术应用于某大型电解锰企业的新建20 kt/a电解锰项目上,实现极板后处理作业自动生产,同时烘干综合能耗降低30%以上的良好效果。

对人工接地装置材料选择要求的探讨

依据电化学腐蚀的原理对人工接地装置材质选择的要求进行研究,着重分析以镀锌扁钢为代表的不同材质的人工接地埋地敷设时的腐蚀过程,并针对不同的工程情况提出相应的解决方案。

室外道路照明接地型式的选择分析

通过分析道路照明10kV电源端的接地系统,本文对TN-S系统和TT系统两种接地型式进行了比较和分析,认为类似室外道路照明这些无等电位联结作用的户外场所,低压配电应优先采用TT系统接地型式,可供类似工程参考和借鉴。

KTX双偏压电极运行放电改善实验研究

研究了在KTX装置中的单偏压电极以及双偏压电极对环形等离子体约束特性的影响。实验发现偏压影响放电时长,通过调节偏压可以使得放电时长达到磁通极限;偏压电极改变放电时长的机制可能是通过改变边界E_(r)改变等离子体位移;实验还观测到施加偏压过程中等离子体电子密度有抬升的现象,并伴随电磁相干模出现。通过对涨落量引起的粒子输运通量频域展开,研究了偏压对粒子输运的影响,发现偏压增强电磁相干模频段涨落引起的粒子输运。

基于蓝藻生物炭粒子电极的3维电化学系统对磺胺甲恶唑的降解

遵循“以废治废”理念,以机械打捞后的太湖蓝藻这一典型固废为原料,采用高温热解和酸/碱处理的方法制备了环境友好的蓝藻基生物炭,并将其作为3维电化学系统(3DES)中的粒子电极,用于高效催化氧化降解去除水中的典型抗生素磺胺甲恶唑(SMX)。经过热解及酸/碱改性后,生物炭更大的比表面积和更丰富的孔道结构提高了SMX在粒子电极表面的富集能力;而蓝藻中原有的铁、氮等元素掺杂在热解生物炭中有效提高了体系中活性氧物种的产生量,使得体系对SMX的去除率和矿化率均显著提高。在最佳制备和运行条件下(粒子电极制备条件:700℃热解和碱改性;3DES运行条件:电流600mA、溶液pH为6、粒子电极用量1.00g/L、水流速300 mL/min、电解质Na_(2)SO_(4)浓度50mmol/L),SMX在120min内去除率可达96%以上;6h后,水体总有机碳(TOC)去除率可达94%。机理研究表明,3DES中,SMX降解的间接氧化作用(占比84.32%)大于直接氧化作用(占比15.68%);间接氧化中,HO^(·)和SO_(4)^(·-)在体系中均被检出,但是,未检测出超氧自由基和单线态氧;而相较于SO_(4)^(·-),HO^(·)对SMX的降解占主导地位(间接氧化中HO占比87.31%)。在连续循环使用6次后,3DES对SMX的去除效率仍能保持在85%以上。研究结果为基于蓝藻生物炭粒子电极的3DES在水处理领域的应用提供了技术支撑和理论依据。

高比能二次锂电池电极材料的储能系统配电网运行建模与仿真研究

对于包含储能系统的配电网运行建模与仿真,传统方法由于缺少对储能系统变量增补约束,导致建模后储能系统的电热转换效率较低。为此,提出高比能二次锂电池电极材料的储能系统配电网运行建模与仿真研究。依据储能系统在配电网中的运行特性,建立储能系统等效电路,并以高比能二次锂电池电极材料的储能系统的经济性指标构建电网运行模型,同时对其加以变量增补约束,以动态描述配电网的运行过程。实例应用结果显示,所提方法能够有效提高储能系统的电热转换效率,建模结果更加可靠。