The influence of charge characteristics of suspension droplets on the ion flow field in different temperatures and humidity

In order to clarify the charging characteristics of suspension droplets in ion flow field under different temperatures and humidity,the effective charging factor used to characterize the charging characteristics of suspension droplets is introduced in this paper,and a calculation method of charging factor is proposed based on the upstream finite element method(FEM).Then,the charging factor under different temperatures and humidity is calculated,and the analytic expression of the charging factor considering the influence of temperature and humidity is obtained by fitting the calculation results.The influence of suspension droplets on the ion flow field is analyzed.The results show that the charging factor is small and increases little with the relative humidity when the relative humidity is less than 60%,and the charging factor is large and increases rapidly with the relative humidity when the relative humidity is more than 60%.At the same relative humidity,the charging factor increases linearly with the temperature.The influence of charged suspension droplets on the ion flow field can be ignored when the relative humidity is less than 60%and must be considered under high temperature and humidity.The calculation method and analytic expression of the charging factor proposed in this paper can be used to model of ion flow field considering the influence of temperature and humidity and provide technical support for the construction of HVDC transmission lines across high temperature and humidity.

Ion Flow Field Calculation of Multi-circuit DC Transmission Lines

An upwind finite element(FE)based algorithm to calculate the ion flow field in the vicinity of multi-circuit DC transmission lines is described.The initial value estimation and boundary condition are optimized,so details of the transmission lines such as bundle conductors and ground wires can be taken into account in the simulation model.Comparison between measured and computed ground level total electrical field and ion current density shows satisfactory agreement.The ion flow field of a ±500 kV HVDC project with bipolar lines on the same tower is simulated.The total electrical field and ion current density on ground level are compared among different line arrangements.

An Investigation of Ionic Flows in a Sphere-Plate Electrode Gap

This paper presents analyses of ion flow characteristics and ion discharge pulses in a sphere-ground plate electrode system. As a result of variation in electric field intensity in the electrode gap, the ion flows towards electrodes generate non-uniform discharging pulses. Inspection of these pulses provides useful information on ionic stream kinetics, the effective thickness of ion cover around electrodes, and the timing of ion clouds discharge pulse sequences. A finite difference time domain （FDTD） based space-charge motion simulation is used for the numerical analysis of the spatio-temporal development of ionic flows following the first Townsend avalanche, and the simulation results demonstrate expansion of the positive ion flow and compression of the negative ion flow, which results in non-uniform discharge pulse characteristics.

On-line Preconcentration and Determination of Trace Metals in Water Samples by Flow Injection Combined with Flame Atomic Absorption Spectrometry via Calix[4]arene Carboxylic Acid Packed Micro-column

An adsorbent calix[4]arene carboxylic acid was employed as the adsorption material for on-line flow in jection（FI） micro-column preconcentration coupled with flame atomic absorption spectrometry（FAAS） determination of trace heavy metals（Cu, Pb, Co, Ni and Cd）. Parameters such as the pH, loading time and flow rate of sample, and the concentration, volume and flow rate of eluent were optimized. The enrichment factors are 50.0, 56.5, 11.6, 12.1 and 19.1 for Cu, Pb, Co, Ni, and Cd, respectively, and a sample throughput of 20 h–1 was obtained. The limits of de tection for Cu, Pb, Co, Ni, and Cd were in a range of 1.56―3.91 μg/L, and the relative standard deviations（RSDs） were less than 2.76%（n=7）. Furthermore, the proposed method was successfully applied to the determination of Cu, Pb, Co, Ni, and Cd in certified reference materials and various water samples.

Momentum-Dependent Symmetry Potential from Nuclear Collective Flows in Heavy Ion Collisions at Intermediate Energies

Within the isospin-dependent quantum molecular dynamics model, we investigate the nuclear collective flows produced in semi-central 197 Au＋197 Au collisions at intermediate energies. The neutron proton differential flows and difference of neutron proton collective flows are sensitive to the momentum-dependent symmetry potential. This sensitivity is less affected by both the isoscalar part of nuclear equation of state and in-medium nucleon- nucleon cross sections. Moreover, this sensitivity becomes pronounced with increasing the rapidity cut.

Influences of nitrogen flow rate on the structures and properties of Ti and N co-doped diamond-like carbon films deposited by arc ion plating

In this paper, Ti-C-N nanocomposite films are deposited under different nitrogen flow rates by pulsed bias arc ion plating using Ti and graphite targets in the Ar/N2 mixture gas. The surface morphologies, compositions, microstructures, and mechanical properties of the Ti-C-N films are investigated systematically by field emission scanning electron mi- croscopy （FE-SEM）, x-ray photoelectron spectroscopy （XPS）, grazing incident x-ray diffraction （GIXRD）, Raman spectra, and nano-indentation. The results show that the nanocrystalline Ti（C,N） phase precipitates in the film from GIXRD and XPS analysis, and Raman spectra prove the presence of diamond-like carbon, indicating the formation of nanocomposite film with microstructures comprising nanocrystalline Ti（C,N） phase embedded into a diamond-like matrix. The nitrogen flow rate has a significant effect on the composition, structure, and properties of the film. The nano-hardness and elastic modulus first increase and then decrease as nitrogen flow rate increases, reaching a maximum of 34.3 GPa and 383.2 GPa, at a nitrogen flow rate of 90 sccm, respectively.

SPES/PVDF Binary Membrane as an Alternative Proton Exchange Membrane in Vanadium Redox Flow Battery Application

SPES/PVDF blends were employed to prepare the ion exchange membranes for vanadium redox flow battery(VRB) application for the first time. The addition of the highly crystalline and hydrophobic PVDF effectively limited the swelling behavior of SPES. The vanadium ion permeability of SPES/PVDF membranes was one order of magnitude lower than that of Nafion 117 membrane and pristine SPES membrane. Single cells with SPES/PVDF composite membranes showed significantly lower capacity loss, higher coulombic efficiency and higher energy efficiency than that with Nafion117 and pristine SPES membranes. The blend membrane with 40 wt% of PVDF(denoted as S_(0.6) P_(0.4)) showed energy efficiency of 83.2% at 30 mA?cm^(-2), which was superior to that of the Nafion117 and SPES membranes. In the self-discharge test, S_(0.6) P_(0.4) membrane showed twice longer duration in open circuit decay than that with Nafion 117 membrane. With all the good properties and low cost, the SPES/PVDF membranes are expected to have excellent commercial prospects as ion exchange membranes for VRB system.

Role of Chloride Ion and Dissolved Oxygen in Electrochemical Corrosion of AA5083-H321 Aluminum-Magnesium Alloy in NaCl Solutions under Flow Conditions

Flow-induced corrosion consists electrochemical and mechanical components. The present paper has to assessed the role of chloride ion and dissolved oxygen in the electrochemical component of flow induced corrosion for AA5083-H321 aluminum-magnesium alloy which is extensively used in the construction of high-speed boats, submarines, hovercrafts, and desalination systems, in NaCI solutions. Electrochemical tests were carried out at flow velocities of 0, ：2, 5, 7 and 10 m/s, in aerated and deaerated NaCI solutions with different sodium chloride concentrations. The results showed that the high rate of oxygen reduction under hydrodynamic conditions causes an increase in the density of pits on the surface. The increase of chloride ions concentration under flow conditions accelerates the rate of anodic reactions, but have no influence on the cathodic reactions. Thus, in the current work, it was found that under flow conditions, due to the elimination of corrosion products inside the pits, corrosion resistance of the alloy is increased.

Effects of Hall Current and Ion-Slip on Unsteady MHD Couette Flow

The unsteady MHD Couette flow of an incompressible viscous electrically conducting fluid between two infinite non- conducting horizontal porous plates under the boundary layer approximations has been studied with the consideration of both Hall currents and ion-slip. An analytical solution of the governing equations describing the flow is obtained by the Laplace transform method. It is seen that the primary velocity decreases while the magnitude of secondary velocity increases with increase in Hall parameter. It is also seen that both the primary velocity and the magnitude of secondary velocity decrease with increase in ion-slip parameter. It is observed that a thin boundary layer is formed near the stationary plate for large values of squared Hartmann number and Reynolds number. The thickness of this boundary layer increases with increase in either Hall parameter or ion-slip parameter.

新型储能技术进展与挑战I:电化学储能技术

新型储能技术日益成为中国建设新型能源体系和新型电力系统的关键技术,已成为中国经济发展的新动能,将在促进可再生能源消纳、实现能源体系转型、提高能源利用效率、减少环境污染等方面发挥重要作用,相关技术研究也在快速发展。开展了该领域的系列评价性综述工作,分为电化学储能技术、物理储能与储热技术、储能集成与规划3个部分,对各类新型储能技术的应用领域、最新研究进展及局限性等问题进行了全面系统的对比分析,并进一步探讨了储能集成、安全、规划调度等储能系统相关领域面临的挑战及发展趋势。第1部分为电化学储能技术,重点对锂离子电池、钠离子电池、液流电池、固态电池和水系电池的技术与工程的相关成果进行了综合分析与讨论。电化学储能技术具有灵活配置的特点,可以满足不同功率和能量的应用需求,锂离子电池技术的成熟度最高,在储能市场占有主体地位,未来进一步发展集中于系统集成和安全技术方面,以推进更大规模的商业化应用。其他一些尚处于基础研究阶段的电池技术也展现出了巨大的发展潜力,比如:固态电池具有更高的安全性,钠离子电池具有优越的低温性能,液流电池具有较长的循环寿命等。

全钒液流电池离子导电膜的选择性

全钒液流电池(VFB)具有功率大、容量大、效率高、安全性能高的特点,近年来在储能应用方面受到广泛关注。离子导电膜作为VFB的关键组件,存在严重的钒离子交叉污染问题,易造成电池容量损失,降低电池使用寿命,因此深入了解VFB离子导电膜的选择性和质子传导对电池性能具有重要意义。本文综述了VFB中阳离子交换膜、阴离子交换膜、两性离子交换膜以及多孔膜等的研究进展,分析了离子导电膜上钒离子的渗透和质子的传输,重点总结了离子导电膜的改性、超薄复合膜设计、膜内微观结构优化及离子基团功能化对提高离子导电膜选择性和电导率的影响,较为全面地阐述了当前VFB离子导电膜选择性和电导率之间的平衡问题,为开发高性能、低成本、长寿命的离子导电膜,促进其商业化发展提供了参考依据,并展望了基于质子传导机制的氢键网络结构、多孔导电膜、低成本的超薄复合膜以及利用分子动力学模拟离子跨膜来提高VFB离子导电膜选择性的研究方向。

环境空气PM_(2.5)中铵离子含量的两种检测方法比较

目的比较离子色谱法与流动注射分析法测定环境空气PM_(2.5)中铵离子含量。采集环境空气颗粒物PM_(2.5)的石英滤膜,各取1/4剪碎后经超纯水超声提取,离心过滤,分别用流动注射法和离子色谱法测定PM_(2.5)中铵离子的含量。结果离子色谱法测定NH_(4)^(+)在0.5~10.0 mg/L范围内拟合曲线为y=0.0710+0.2214x-0.0058x^(2),r=0.9997,检出限0.017μg/m^(3),定量限0.068μg/m^(3),回收率91.0%~96.6%,RSD 0.05%~0.08%(n=6);流动注射法测定NH_(4)^(+)在0.02~1.00 mg/L范围内线性关系良好,y=22.576x+0.1333,r=0.9999,检出限0.003μg/m^(3),定量限0.012μg/m^(3),加标回收率为105%~114%,RSD在0.54%~2.06%(n=6)之间。利用两种方法同时测定16份滤膜样本,测定结果差异无统计学意义(t=1.080,P>0.05)。结论两种方法均具有良好的线性关系、精密度及准确度,流动注射分析法与离子色谱法相比有检出限低,检测时间短等优势。

Chemiluminescence flow Sensor for determination of the Ammonium ion

A novel chemiluminescence (CL) sensor for NH4+ combined with flow injection analysis is presented in this paper. It is based on the inhibition effect of NH4+ on the CL reaction between luminol, immobilized electrostatically on an anion-exchange column, and hypochlorous acid electrogenerated on-line. The sensor responds linearly to NH4+ concentration in 1.0x10(-6)-4.0x10(-9) g/ml range. A complete analysis could be performed in 1 min. The system is stable for 200 determination.

Zonal Flows and Geodesic Acoustic Mode Oscillations in Tokamaks and Helical Systems

This paper reviews the theoretical foundations of zonal flow, putting emphasis on the linear response function of plasma to the external flow drive. An extension of the theory is made in order to apply it to helical systems and to study the properties of the zonal flow in the low frequency range. Further refinement of the theory is made incorporating the orbital effects of particles more precisely, and the role of neoclassical polarization current is identified.

五个杨树品种生长、光合生理及根尖离子流速特性比较分析

通过比较不同品种杨树(Populus)的生长、光合生理及根尖离子流速特性差异,为速生适应性强品种的早期选育提供参考。以渤丰3号杨(P.×euramericana‘Bofeng 3’)、渤丰1号杨(P.×euramericana‘Bofeng 1’)、西雄1号杨(P.×euramericana‘Xixiong 1’)、中雄7号杨(P.×euramericana‘Zhongxiong 7’)和中雄4号杨(P.deltoides×P.suaveolens cl.‘Zhongxiong 4’)5个杨树品种1年生苗为研究对象,于正常培养条件下的试验开始和试验结束(30 d)时分别测定株高、地径等生长指标,并于10、20、30 d时分别测定幼苗的叶片数量、单叶面积、叶长、叶宽、瞬时净光合速率(P_(n))、胞间CO_(2)摩尔浓度(C_(i))、气孔导度(G_(s))、蒸腾速率(T_(r))、叶绿素相对含量以及根尖K^(+)、Ca^(2+)、H^(+)流速等指标,经过30 d的正常管理,5个品种的株高生长量之间的差异达到显著水平,由高到低依次为中雄4号杨、西雄1号杨、渤丰3号杨、中雄7号杨、渤丰1号杨;其中光合特性指标和蒸腾速率渤丰1号杨均表现为最大,中雄4号杨均表现为最小,但是中雄4号杨的单叶面积((57.49±2.37)cm^(2))、总叶面积((1721.10±28.59)cm^(2))、单株净光合速率((17863.10±910.21)μmol·m-2·s-1)和水分利用率((3.15±0.06)μmol·mmol^(-1))均表现为最大,且K^(+)外排流速最慢,为(62.68±0.45)pmol·cm^(-2)·g^(-1),Ca^(2+)内流流速最快,为(-74.24±1.29)pmol·cm^(-2)·g^(-1),而渤丰1号的单株净光合速率((8539.70±164.64)μmol·m-2·s-1)和水分利用率((2.64±0.07)μmol·mmol^(-1))最小,且K^(+)外排流速((130.81±1.71)pmol·cm^(-2)·g^(-1))最快,Ca^(2+)内流流速((-34.43±0.84)pmol·cm^(-2)·g^(-1))最慢。综上所述,5个杨树品种中,中雄4号杨总叶面积、单株净光合速率、水分利用率最高,蒸腾速率最小,根尖K^(+)外排流速最慢,Ca^(2+)内流流速最快,植物体内K^(+)、Ca^(2+)离子含量最多,H^(+)最活跃,株高生长表现最好,可能具有潜在的较强环境适应能力,适宜种植的范围更广。

基于风速概率分布与风切变指数的直流输电线路离子流场数值模拟方法

特高压直流(UHVDC)输电线路下方的离子流场是电磁环境的重要评估指标之一。风速作为常见也是影响较大的因素之一,有着明显的地域特点。为了避免资源浪费,在对地高度设计时,应考虑到不同地区的风速分布差异,而不是用过大裕度换取安全度。为此,该文提出一种基于风速概率分布与风切变指数的输电线路离子流场数值模拟方法。该方法通过待计算地区的风速数据构建Weibull风速概率分布函数模型,选择风速数据在95%以内的最大临界风速作为参考值,考虑风速传感器的安装高度,根据风切变指数计算场域不同高度处的风速分布,作为离子流场计算中不同高度节点的风速输入量。结果表明,引入风切变指数后的离子流密度与合成电场强度误差分别下降了16.2百分点和3.8百分点,明显优于传统固定风速模型。并以昆明地区某±800kV直流输电线路为例,采用该方法进行了计算。该方法能够有针对性地考虑输电线路所处区域的风速影响,特别是在高海拔高风速地区,可为输电线路在合成电场安全限值下的对地高度设计提供参考依据。

工质流量对ECR离子源束流影响研究

栅格进气道电子回旋共振(electron cyclotron resonance,ECR)离子源推进剂供给压强低、无阴极,有应用于吸气式电推进系统的潜力。流量对离子源的束流影响显著,当流量超过临界流量时,离子束流的增长受到抑制。为明晰限制离子束流增长的根本原因,开展不同流量下氮工质栅格进气道ECR离子源的Langmuir探针诊断实验,并基于诊断结果计算了寻常(ordinary,O)波截止区和电子获能指标的分布。研究结果表明,当流量低于临界流量时,随着流量增加,离子密度快速增加,限制离子束流增长的主要因素是中性气体密度。当流量超出临界流量时,O波截止区几乎覆盖整个等离子体产生区域,这导致电子能量获取效率下降了一个数量级。此时,限制离子束流增长的主要因素转变为电子温度。

流动注射法检测枸杞中二氧化硫残留量的方法比较及风险评估

近年来自动化检测设备以及对应方法相继涌现,本研究使用在线蒸馏-流动注射法与国标中酸碱滴定法、离子色谱法对枸杞中二氧化硫残留量进行检测比较。结果表明,三种方法的测定结果并无显著性差异。在线蒸馏-流动注射法RSD在1.5%~2.4%之间,加标回收率在86.1%~92.7%之间,因其具有自动化程度高、检测周期短的优势,更适合大批量样品的快速准确检测。用在线蒸馏-流动注射法对106批次红枸杞中的二氧化硫残留量进行检测分析,并对枸杞中的二氧化硫残留量进行暴露风险评估。结果显示,二氧化硫超标率达21.7%,枸杞中二氧化硫残留尚未对健康构成威胁。

储能电池建模与状态估计研究进展

储能电池具有能够平滑可再生能源输出,提高电力系统灵活性和应对电力需求峰谷等优势,有助于推动可再生能源发展,从而应对环境污染和能源紧缺的双重压力。目前市场主流的储能电池为锂离子电池,具有高比能特性,同时新型储能电池也在蓬勃发展,其中全钒液流电池具有高安全性的优势,液态金属电池具有超长循环寿命,在电力储能领域具有重要应用前景。储能电池的建模和状态估计对提高储能电池系统性能,确保其安全性以及优化维护效率至关重要,因此文中对锂离子电池、全钒液流电池和液态金属电池的建模和状态估计进行综述。首先,介绍了储能电池状态估计的整体框架,对基于实验的方法、基于模型的方法和基于数据驱动的方法进行整体介绍,并对荷电状态(state of charge,SOC)、健康状态(state of health,SOH)和剩余使用寿命(remaining useful life,RUL)进行概括;然后,从原理出发,分别总结了不同储能电池体系的内部工作过程、模型构建、状态估计与电池管理过程;最后,对不同储能电池体系的主要工作特性进行横向对比和总结,旨在为储能电池选择和发展提供启示。

电积铜升级改造研究

本文主要描述在净液工段生产电积铜的现状问题,将电积铜放置生产工段生产所要解决的问题,以及作者自身提出的一些解决方法。从提高电积铜产品质量和技术水平,降低生产成本和劳动强度等方面进行了阐述。