隔膜及电液量对GNYZ3蓄电池内气压影响

为了降低电池内气压,避免电池过充电漏气,进行了几种不同材质的隔膜及不同电液量对GNYZ3板式蓄电池内气压影响的试验,确定最佳隔膜为维纶布,此时的合理电液量为电池电液量应控制在15.5～16 g;环境温度在15～25℃范围内,5小时率电流充电7 h或10小时率电流过充18h的方法进行过充电,电池内气压不会高于3.0 MPa,使用时环境温度在20～40℃范围内以5小时率电流充电7 h,电池内气压不会高于3.0 MPa。

关于比例排量阀和恒功率阀的阀口设计改进技术分析及试验效果

针对国外BOSCH公司的二种阀的基本结构原理,分析、研究、探讨,通过设计改进阀口,提高产品试验特性,得出了具有本国高新技术的产品,为后期比例排量阀、恒功率阀的设计、加工、试验奠定了基础。

Effect of the amount of zinc-doped on the electrochemical performance of nickel hydroxide

The nickel hydroxide prepared by micro-emulsion method was doped by coprecipitated Zn. The effect of the amount of zinc-doped on the properties of Ni(OH)2 such as the reversibility of the electrode reaction, the charge efficiency and active material utilization ratio of nickel electrode, and discharge specific capacity was studied by cyclic voltammetry and constant current charge-discharge tests. The results indicate that the specific discharge capacity of nickel hydroxide obtained by micro-emulsion method is much less than its theoretical value because the transfer of electrons and the diffusion of protons H+ are hindered owing to its crystal grain size in a nanometer range and thus possessing higher crystal interface resistance. The crystal cells are swelled and the crystal defects increased in prepared material due to part of Ni2+ substituted by Zn2+ when zinc and nickel hydroxide are coprecipitated. Hence, the electrons and protons H+ in the electrode reaction are transferred easily, the electrochemical behavior of nickel electrode is improved and discharge specific capacity is promoted. However, the performance of Ni(OH)2 is gradually enhanced with the addition of zinc-doped at first, while slowly decreased after the content of zinc is added to a certain value. The best electrode reaction reversibility, the highest electrode charge efficiency, the highest active material utilization ratio and the largest specific capacity on discharge are available when the mass fraction of Zn doped in nickel hydroxide by coprecipitation reaches 2.5 %.

Thermodynamic properties and heat capacity of Ru metal in HCP,FCC,BCC and liquid state

Isometric heat capacity cv and isobar heat capacity cp of Ru metal in HCP,FCC,BCC and liquid state were calculated by using pure element systematic theory.The results are in good agreement with joint army-navy-air force(JANAF) experimental value and the calculation result by first-principle(FP) method.But the results have great differences in contrast to Scientific Group Thermodata Europe(SGTE) database.The cause is found that it cannot neglect the electron devotion to heat capacity to adjust cp in one-atom(OA) method.The disparity between OA method and SGTE database was discussed.The main cause is that OA method adopts the crosspoint with iso-Ec-line and iso-a-line in hybritriangle to determine the properties,but SGTE database is obtained by extrapolation from activity measurements and critical assessment of data from a large number of binary system.Thermodynamic properties of Ru metal in HCP,FCC,BCC and liquid state,such as entropy S,enthalpy H and Gibbs energy G were calculated.Therefore,the full description of thermodynamic properties from 0 K to random temperature is implemented.

Electrochemical response to biomass of bacterial cells of Achromobacter sp. CH-1 growth

A simple and effective method has been developed to reflect the growth of bacteria CH-1via the potential of the solution.The results indicate that during the bacterial cultivation,the biomass increases and the potential of the solution decreases over time.The relationship between biomass and potential of the solution could be expressed by the equation with constants of a and b whichare all related to species,batch,number,and growth environment of bacterial.When the initial pH value is10and the initial biomassis6.55×107cell/mL,the correlated equation of the biomass and the potential of the solution could be divided into two segments.Thegrowth of bacteria CH-1is different under various experimental conditions,but the biomass is directly related to the potential of thesolution regardless of the conditions of different initial pH values and bacteria number.

Charge Gap in One—Dimensional Extended Hubbard Model

By using the bosonization and renormalization group methods, we have studied the low energy physical properties in one-dimensional extended Hubbard model. The formation of charge and spin gaps is investigated at the half-filled electron band. An analytical expression for the charge gap in terms of the Coulomb repulsive interaction strength U and the nearest-neighbour interaction parameter V is obtained.

Influence of zinc on electrochemical discharge activity of Mg-6%Al-5%Pb anode

Mg-6%Al-5%Pb(mass fraction) anodes with different contents of zinc were prepared by melting and casting.The electrochemical discharge behavior of these anodes in 3.5% NaCl solutions was investigated by galvanostatic test and electrochemical impedance spectroscopy(EIS).The microstructures and the corroded surfaces of these anodes were studied by scanning electron microscopy(SEM) and emission spectrum analysis(ESA).The phase structures and the corrosion products of the anodes were analyzed by X-ray diffraction(XRD).The results show that zinc promotes the grain refinement of Mg-6%Al-5%Pb anode and makes the average discharge potential of Mg-6%Al-5%Pb anode more negative during galvanostatic test.Mg-6%Al-5%Pb anode with the addition of 1%(mass fraction) zinc has the best electrochemical performance.The activation mechanism of zinc to Mg-6%Al-5%Pb anode is as follows:The hydrolyzation of dissolved Zn2+ ions reduces the pH value of the solution near the surface of the anode and accelerates the dissolution of Mg(OH)2 film;The precipitated Zn(OH)2 with similar structure as Mg(OH)2 combines with Mg(OH)2 film easily and makes it break down.

Development of timer based on liquid level measurement system

This paper describes the design and development of the timer based on liquid level measurement system in which timer 555 is used in astable mode. The capacitor charging time i. e. the ON time pulse width of the timer output waveform which is measured using a digital storage oscillator （DSO）,is linearly proportional to the capacitance of a co-axial cylindrical capacitive transducer, and this capacitance once again linearly varies with the change in liquid level. Hence, we obtain a linear relationship between the liquid level and the capacitor charging time. The main advantages of this developed system are linear input-output relationship, small in size, easily portable, cost effective, and independent on the ambient temperature effect. The system can also be exploited to measure dielectric constant of liquid or solid in various process industries.

Fuzzy iterative learning control of electro-hydraulic servo system for SRM direct-drive volume control hydraulic press

A new kind of volume control hydraulic press that combines the advantages of both hydraulic and SRM(switched reluctance motor) driving technology is developed.Considering that the serious dead zone and time-variant nonlinearity exist in the volume control electro-hydraulic servo system,the ILC(iterative learning control) method is applied to tracking the displacement curve of the hydraulic press slider.In order to improve the convergence speed and precision of ILC,a fuzzy ILC algorithm that utilizes the fuzzy strategy to adaptively adjust the iterative learning gains is put forward.The simulation and experimental researches are carried out to investigate the convergence speed and precision of the fuzzy ILC for hydraulic press slider position tracking.The results show that the fuzzy ILC can raise the iterative learning speed enormously,and realize the tracking control of slider displacement curve with rapid response speed and high control precision.In experiment,the maximum tracking error 0.02 V is achieved through 12 iterations only.

Local Measurement of Gas-Liquid Bubbly Flow with a Double-Sensor Probe

A double-sensor probe was used to measure local interfacial parameters of a gas-liquid bubbly flow in a horizontal tube. The parameters included void fraction, interfacial concentration, bubble size distribution, bubble frequency and bubble interface velocity. The authors paid special attention to the probe design and construction for minimizing measurement errors. Measures were also taken in the design of sensor ends for preventing corrosions in the flow. This is an effort to improve the current double-sensor probe technique to meet the ever-increasing needs to local parameter measurements in gas-liquid two-phase flows.

The Energy Balance of the Electro-Hydraulic Linear Actuation System

The variable gas exchange valve actuation systems have been developed in order to improve the efficiency of the combustion process. The electro-hydraulic valve actuation （EHVA） systems have good power to weight ratio, high maximum force and good controllability. The disadvantages are limited frequency bandwidth and energy recovery. Each component of the EHVA system has certain energy consumption, which is characteristic to the component. In this study the power consumptions of the components are investigated by means of the simulation. The investigated components are a hydraulic pump, a hydraulic accumulator, a control valve, and hydraulic lines connecting the components. The pressure losses caused by the oil flow are most significant in the control valves, 50-60% of the total energy consumption. If the stored kinetic energy of the actuator and moving oil masses could be reused, the energy consumption could be up to 25% better.

Electrochemical Energy Storage Technologies and Applications

The current need to fasten the implementation of renewable energies greatly depends on the development of competitive storage devices, and while there is not a single technology which is likely capable to competitively cover the wide range of possible demands, electrochemical technologies are one of the most promising for many of them. For the realization of this promise, new materials fulfilling criteria such as high energy density, high power density, competitive cost, reliability, and environmental compatibility need to be developed in the near future. Electrochemical energy storage devices can be classified into two main technologies： supercapacitors and batteries （including redox flow batteries）. Materials and applications for these technologies are discussed and compared, listing current status, technical and strategic challenges.

A Mathematical Model for Pulsating Flow of Ionic Fluid under an Axial Electric Field： EMF Effect on Blood Flow

The present work introduces a mathematical model for ionic fluid that flows under the effect of both pulsating pressure and axial electromagnetic field. The fluid is treated as a Newtonian fluid applying Navier-Stokes equation. The fluid is considered as a neutral mixture of positive and negative ions. The effect of axial electric field is investigated to determine velocity profiles. Hydroelectric equation of the flow is deduced under dc and ac external electric field. Hence the effect of applied frequency （0-1 GHz） and amplitude （10-350 V/m） is illustrated. The ultimate goal is to approach the problem of EMF field interaction with blood flow. The applied pressure waveform is represented as such to simulate the systolic-diastolic behavior. Simulation was carried out using Maple software using blood plasma parameters; hence velocity profiles under various conditions are reported.

Electrochemical Performance and Capacity Fading Mechanism of LiFePO4 at Different pH Aqueous Electrolyte Solutions

The electrochemical stability of LiFePO4 in a Li＋-containing aqueous electrolyte solution is critically dependent on the pH value of the aqueous solution. It shows a considerable decay in capacity of LiFePO4 upon cycling when the pH value is increased to 11. The mechanism responsible for the capacity fading is extensively investigated by means of cyclic voltammogram, ac impedance, charge/discharge, ex situ X-ray diffraction, and chemical analysis. LiFePO4 is relatively electrochemically stable in LiNO3 aqueous solution with pH=7. But the electrochemical performance of LiFePO4 in aqueous electrolyte is inferior to that in organic electrolyte. It is attributed to the loss of Li and the Fe, P dissolution during prolonged charge-discharge in aqueous medium. A precipitate is formed on the surface of LiFePO4 electrodes. It results in the change of crystalline structure, a large electrode polarization, and capacity fading.

Electrochemical Determination of Reduced Glutathione at Multiwalled Carbon Nanotubes/Poly(bromocresol green) Modified Glassy Carbon Electrode

A multiwalled carbon nanotubes/poly(bromocresol green) modfied glassy carbon electrode (MWNTs-PBG/GCE) was used to investigate the electrochemical behavior of reduced glutathione(GSH). GSH showed an irreversible oxidation process on MWNTs-PBG/GCE with an oxidation peak at 0.77 V(vs. SCE) in a phosphate buffer solution(pH=4.0). The kinetic parameters of the electrochemical behavior of GSH on MWNTs-PBG/GCE were calculated. Under the optimal conditions and with the help of amperometric method, a linear relationship was obtained between the oxidation peak current and GSH concentration in the range from 2×10-7 mol/L to 5×10-6 mol/L with the detection limit as 1×10-8 mol/L(signal-to-noise ratio of 3). The current reached the steady-state current within about 5 s. The modified electrode surface had very good reproducibility and stability.

Correlation of the Cerebral Microvascular Blood Flow with Brain Temperature and Electro-Acupuncture Stimulation

Objective:To investigate the relationship between the temperature and the microvascular blood flow of the cerebral cortex, and the influence of electro-acupuncture (EA) on the cortical microcirculation. Methods: High temperature spots on the anterior ectosylvian and low temperature spots on the posterior suprasylvian on the cortical surface of 20 cats were identified using cortical infrared thermography (CIT); the blood flow in the microcirculation on these spots was measured with laser-Doppler flowmetry. EA was given at Zusanli (ST 36) and changes in the blood flow in the cerebral cortex microcirculation were detected. Results: 1) The mean temperatures on the high (34.83±0.24°C) and low (32.28±0.27°C) temperature spots were significantly different (P<0.001); this was indicative of a temperature difference on the cortical surface; 2) The average blood flow in the microcirculation of the high (266.8±19.2 PU) and low (140.8±9.9 PU) temperature spots was significantly different (P<0.001). 3) On the cortical high temperature spots, the mean blood flow in the microcirculation significantly increased from 266.8±86.8 PU before EA, to 422.5±47.4 PU following 5 minutes of EA (58.35%; P<0.01), and 431.8±52.8 PU 5 minutes after ceasing EA (61.84%; P<0.01). 4) On the low temperature spots, there were no significant differences in blood flow following 5 minutes of EA (146.3±11.5 PU), and 5 minutes after ceasing EA (140.5±11.6 PU), when compared with that before acupuncture (140.8±9.9 PU; P>0.9). Conclusion: The high temperature spots of the cortex are active functional regions of neurons with higher blood flow and a stronger response to EA. EA induces a significant increase in blood flow in the high temperature spots of the cortex.

Solid electrolyte interphase in water-in-salt electrolytes

The water-in-salt strategy successfully expands the electrochemical window of the aqueous electrolyte from1.23 to~3.0 V,which can lead to a breakthrough in the energy output of the aqueous battery system while maintaining the advantage of high safety.The expanded electrochemical window of the water-in-salt electrolytes can be ascribed to the decreased water activity and the solid electrolyte interphase formed on the anode.The solid electrolyte interphase in the aqueous system is not fully understood,and the basic composition,the structure,and the formation mechanism are still cloaked in mystery.This perspective summarizes the published research with emphasis on the most possible formation mechanism and composition of the interphase layer in the aqueous system.Further understanding of the interphase as well as rounded assessment of the water-in-salt electrolyte in practical operating conditions is encouraged.The full understanding of the interface will guide the design of aqueous electrolytes and help to build novel aqueous batteries with high safety and high energy density.

Visualization of Film Wavelike Characteristics and Measurement of Film Thickness in Spray Cooling

An experimental investigation was performed to study the heat transfer in an eight-nozzle spray cooling system with de-ionized water as the working fluid. Visualization of the liquid-solid contact area and the flow near the heated surface was made using a microscopic lens system in conjunction with an advanced high-speed camera. The film thickness and film wavelike characteristics under liquid volume flow rates ranged from 2.78×10 -6 m 3 /s to 1.39×10 -5 m 3 /s and surface temperatures between 22℃ and 78.2℃ were examined respectively. The development process of the liquid film on the heated surface was observed. The local mean film thickness, the film wavelike characteristics and the behavior of the bubbles appeared in the liquid film were captured using an image processing technique. It is discovered that there exists a climax of local mean film thickness during the starting process of spray cooling. When the liquid film reaches the dynamic stable state, the dimensionless mean film thickness decreases with the increase of the liquid volume flow rate, and increases with the increase of surface temperature generally. Besides, the volume flow rate has a more significant impact on the wavelength and amplitude of the liquid film compared to the surface temperature.

Novel ionic liquid based electrolyte for double layer capacitors with enhanced high potential stability

Developing electrolyte with high electrochemical stability is the most effective way to improve the energy density of double layer capacitors(DLCs), and ionic liquid is a promising choice. Herein, a novel ionic liquid based high potential electrolyte with a stabilizer, succinonitrile, was proposed to improve the high potential stability of the DLC. The electrolyte with 7.5 wt% succinonitrile added has a high ionic conductivity of 41.1 m S cm^(-1) under ambient temperature, and the DLC adopting this electrolyte could be charged to 3.0 V with stable cycle ability even under a discharge current density of 6 A g^(-1). Moreover, the energy density could be increased by 23.4% when the DLC was charged to 3.0 V compared to that charged to 2.7 V.

Ab initio simulation of the sum-frequency generation response of optically active liquids in the presence of a dc electric field —determination of the absolute molecular configuration

Quantum chemical computations have been performed to evaluate the first and second hyperpolarizability quantities of the interference term, linear in the external static electric field, that appear in the electric field-induced sum-frequency generation signal of chiral liquids. These are performed at the time-dependent Hartree-Fock level on the prototypical 1,1′-bi-2-naphtol chiral species.