Adsorption Kinetics of Pb^(2+) and Cu^(2+) on Variable Charge Soils and Minerals:Ⅰ.Technique

A new technique for studying the adsorption kinetics of heavy metals,Pb^2+ and Cu^2+,on variable charge surfaces was established with two selective electrodes and microcomputer control system.Feasibility of the technique,including interference of other ions (mainly Fe^3+ and Al^3+),response time of electrodes,and the pH range of testing,was studied.Comparision with the most widely used miscible displacement technique,which was considered insufficient in studying 30-minute rapid reactions,at present time showed that the new technique was more advantageous in testing in situ,easy to operate,and economic.

Numerical and Experimental Investigation into Plane Charge Explosion Technique

Plane charge explosion technique (PCET) is one of the major techniques frequently used in large-scale blast-resistant structure tests. An FEM model was established, which can simulate the process of air releasing from the blast cavity. The effects of the charge density, the interval of the charge strip, the distance of the charges from the structure, and the mass of backfill soil on the overpressures applied on the tested structures were analyzed by the FEM model. The quantitative relationships between the peak value and the duration of the overpressure and the above-mentioned affecting parameters were established. Agreement between numerical results and the test data was obtained.

CALCULATION AND EXPERIMENTAL INVESTIGATION OF ELECTRIC FIELDS INDUCED BY ELECTRODES IN ELECTROSTATIC CHARGED POWDER SPRAYING TECHNIQUE

Electric fields induced by ring and pin electrodes in electrostatic charged powder sprayingtechnique are analysed. The fundamental formulae to deseribe these fields have been built up. Theseformulae could be used to design electrostatic charged podwer spraying system. The chargingeffectiveness of ring and pin electrode is experimentally investigated and compared each other. Theperformance of ring electrode is better than that of pin electrode.

Adsorption Kinetics of Pb^(2+) and Cu^(2+) on Variable Charge Soils and Minerals: Ⅲ. Adsorption Kinetics of Pb^(2+) Within 30 Minutes

The adsorption kinetics of Pb^2+ on different soils and minerals with variable charges was studied by the two ion-selective electrode technique at different pH and concentrations.The results showed that more than 95% of adsorption on all the samples occurred during the first 5 minutes.All adsorption time-dependent data could fit the surface second-order equation very well.The values of Xm were goethite>kaolinite,and latosol>red soil at the same initial reaction concentration.The values of k were kaolinite>>goethite,and latosol>red soil at the same reaction pH and initial concentration.The higher the suspension pH,the faster the adsorption occurred.The meaning of Xm got by the two ion-selective electrode technique(one kind of batch technique) was different from that by the miscible displacement technique in that the former was only the equilibrium adsorption amount at a definite concentration and pH,but the latter was almost equal to the adsorption capacity at a definite pH with much less influence of concentration.One Pb^2+ was supposed to occupy two adsorption sites as the adsorption mechanism is concerned.

Effect of transient space-charge perturbation on carrier transport in high-resistance CdZnTe semiconductor

The polarization effect introduced by electric field deformation is the most important bottleneck of CdZnTe detector in x-ray imaging. Currently, most of studies focus on electric field deformation caused by trapped carriers;the perturbation of electric field due to drifting carriers has been rarely reported. In this study, the effect of transient space-charge perturbation on carrier transport in a CdZnTe semiconductor is evaluated by using the laser-beam-induced current(LBIC) technique.Cusps appear in the current curves of CdZnTe detectors with different carrier transport performances under intense excitation, indicating the deformation of electric field. The current signals under different excitations are compared. The results suggest that with the increase of excitation, the amplitude of cusp increases and the electron transient time gradually decreases. The distortion in electric field is independent of carrier transport performance of detector. Transient space-charge perturbation is responsible for the pulse shape and affects the carrier transport process.

Measurement of cathode surface temperature using the method of CCD imaging in arc discharge

A two-wavelength pyrometry device using ordinary array CCD (charge coupled device) to collect the ra- diation data in the horizontal and vertical directions has been developed for measuring the cathode surface temperature during the arc discharge. Analyses of experimental results show that the device can make the measurement of the cathode surface temperature feasible. The cathode surface temperatures measured are lower than the melting point of tungsten (3653 K), and the arc current, cathode diameter, and the cathode length are the main influencing factors of the cathode surface temperature.

计及经济性和低碳性的光储充一体化电站多目标优化配置

为充分挖掘光储充一体化电站经济效益及碳减排效益,实现站内组成单元合理配置,文中提出一种计及经济性和低碳性的光储充一体化电站多目标优化配置方法。首先,根据充电站内各模块的功能及需求,探究光储充电站中碳排放的来源,建立站内各模块成本、碳排放的数学模型。然后,以系统年投资运行成本和碳排放量最小为目标,使用基于三黑洞捕获策略的多目标粒子群算法,对不同负荷场景下电站各组成模块进行优化配置,得出各场景下电站各组成模块的最优配置方案。对比结果表明,文中所提方法可有效降低规划运行时的成本和碳排放量,提高电站经济及环境效益。最后,采用逼近理想解排序法得出最优场景下的折衷优化方案,可为当前光储充一体化电站的投资建设提供参考。

基于深度学习的激光无线充电保护系统

为了提高智能家居远程激光无线充电系统使用的安全性,采用了一种基于深度学习的激光无线充电保护系统。针对贴附于智能家居表面的光伏电池属于小目标,具有不易识别的难点,改进得到了YOLOv7-NH网络模型,设立保护监测区,并融入帧间差分法用于实时监控充电区域;通过创设原理分析-算法框架搭建-环境调试等环节,编写了对充电目标所在区域进行图像监控的保护算法,并搭建了测试系统。结果表明,当激光发射端与充电目标距离在10 m以内,基于该算法搭建的保护系统的响应启动时间均低于1 ms,即当移动异物以低于常规速率1.5 m/s进入大小为40 mm×40 mm的保护监测区时,该保护系统能够在其运动到激光束所在光路前停止激光发射。这一结果对室内激光远程无线充电保护技术的发展是有帮助的。

σ-dominated charge transport in sub-nanometer molecular junctions

Quantum tunneling conductance of molecular junctions originates from the charge transport through theπ-orbitals(π-transport)and theσ-orbitals(σ-transport)of the molecules,but theσ-transport can not be observed due to the more rapid decay of the tunneling conductance in theσ-system compared to that in theπ-system.Here,we demonstrate that dominantσ-transport can be observed inπ-conjugated molecular junctions at the sub-nanometer scale using the scanning tunneling microscope break junction technique(STM-BJ).We have found that the conductance of meta-connected picolinic acid,which mainly occurs byσ-transport,is∼35 times higher than that of its para-isomer,which is entirely different from what is expected fromπ-transport through these systems.Flicker noise analysis reveals that the transport through the meta-connection exhibits more through-bond transport than the para-counterpart and density functional theory(DFT)shows that theσ-system provides the dominant transport path.These results reveal that theσ-electrons,rather than theπ-electrons,can dominate charge transport through conjugated molecular junctions at the sub-nanometer scale,and this provides a new avenue toward the future miniaturization of molecular devices and materials.

新能源汽车常见故障及维修技术

本文针对新能源汽车的常见故障型及维修技术进行了较为全面和系统的阐述。内容涉及新能源汽车电池、电机驱动、电子控制和充电系统四个方面的典型故障原因分析,如电池容量衰减、电机异响、电子控制单元故障、充电速度下降等,然后针对各类典型故障描述了对应维修的技术手段,涵盖了电池检测、模块更换、软件调试等多种方式。本文旨在为新能源汽车故障治理和维修保养提供参考。

高阶显微分析技术在CDM失效问题上的应用

带电器件模型(CDM)是引起静电放电(ESD)失效问题的主要模型,特别是先进制程和高速射频电路,CDM的故障定位与根因分析对优化ESD设计和改善ESD防护至关重要。借助高阶显微分析技术,如等离子体聚焦离子束(PFIB)、导电原子力显微镜(C-AFM)、电子束感应电流(EBIC)、透射电子显微镜(TEM),可以快速准确地定位失效位置并确认失效机理。通过分析先进制程芯片射频电路增益降低问题,确定了CDM泄放路径与失效形貌,并解释了CDM的损伤机理。通过高阶显微分析技术研究CDM失效问题,有助于优化ESD防护电路,提高芯片可靠性。

基于改进TOPSIS-模糊贝叶斯网络的电池SOC和SOH联合估计方法

为实现储能电池全生命周期下的电池状态动态评估,提高复杂工况下锂离子电池模型的自适应性与状态估计的准确性,提出基于改进逼近理想解排序法(technique for order preference by similarity to an ideal solution,TOPSIS)-模糊贝叶斯网络的电池荷电状态(state of charge,SOC)和健康状态(state of health,SOH)联合估计方法。应用多阶电阻-电容电路(resistor-capacitance circuit,RC)模型、使用节点-支路框架构建电池的等效电路模型,通过基尔霍夫定律与欧姆定律对二阶RC电池等效电路模型中的并联回路进行电气特性分析,构建空间状态方程及等效输出方程;对构建的状态方程进行离散化处理,分别定义并联独立回路离散化零输入响应、零状态响应,分析离散化电池模型状态空间方程;将专家打分法引入TOPSIS算法中进行电池SOC量化估计,结合融入模糊尺度的贝叶斯网络,在相同时间分布尺度下通过电池SOH值计算电池观测样本中对应的SOC值,实现电池SOH与SOC联合估计。实验结果表明:所提方法可有效估计不同离散空间尺度下的电池SOC和SOH结果,估计方法具有良好的准确性与较高的精度。

BREAK-UP MECHANISM OF METAL DROPLETS GENERATED BY AN ELECTROHYDRODYNAMIC TECHNIQUE

Nanometer powders can be produced by an electrohydrodynamic technique. The breakup mechanism of the metal droplets generated by the electrohydrodynamic technique was analysed. It showed that the applied voltage, the electric field Btrength, the properties of the molten metal and the volumetric flow rate of the molten metal directly effect the breat-up extent of the metal droplets.

立体弯折线缆线束电磁耦合分析的时域混合算法

受复杂系统布线空间的制约,线缆通常为线束结构,并呈现弯折和空间立体分布形态。目前,针对立体弯折线缆线束(BSCs)的电磁耦合,仍缺乏高效的时域建模分析方法。因此,该文基于时域有限差分(FDTD)方法和传输线(TL)方程,提出自适应线缆网格技术,结合高效插值技术和电荷守恒定律,研究了一种高效的时域混合算法,实现立体弯折线缆线束的电磁耦合时域快速同步计算。首先,将立体弯折线束整体结构按照弯折节点分解成多段独立的子线束。然后,基于传输线方程和FDTD方法,结合自适应线缆网格技术和插值技术,构建各段空间立体分布的子线束电磁耦合模型,并求解得到线束沿线各点的瞬态响应。最后,根据电荷守恒定律,构建弯折节点的等效电路模型并求解得到节点处的电压,实现各段子线束之间的干扰信号传输。通过理想导电板上和屏蔽机箱内立体弯折线束电磁耦合的数值模拟,从计算精度和耗用时间方面与CST和FDTD-SPICE的仿真结果进行对比,验证所提方法的正确性和高效性。

乙基紫三波长叠加共振光散射光谱法测定酒石酸泰乐菌素含量

基于酒石酸泰乐菌素与乙基紫在pH 2.8的Clark-Lubs缓冲溶液介质中发生反应,建立了三波长叠加共振光散射光谱法测定酒石酸泰乐菌素的新方法。以三波长叠加法探讨了适宜的反应条件和共存物质的影响,研究结果发现,该体系分别在波长325 nm、510 nm、670 nm处产生了3个特征峰,并且酒石酸泰乐菌素浓度均在0.04~0.24 mg/L范围内呈良好线性关系,其线性回归方程分别为ΔI_(RLS)=6187.1c+456.1、ΔI_(RLS)=8138.6c+248.03和ΔI_(RLS)=6087.1c+224.53;其对应的相关系数R分别为0.9992、0.9990和0.9990;检出限分别为0.092 mg/L、0.089 mg/L和0.100 mg/L。而采用三波长叠加检测法时,其线性回归方程为ΔI_(RLS)=20413c+479.6,R为0.9999,检出限为0.030 mg/L。三波长叠加检测法的灵敏度约为单波长检测法灵敏度的3倍。建立的乙基紫三波长叠加共振光散射光谱法具有成本低、灵敏度高等优点,可成功应用于酒石酸泰乐菌素含量检测。

石墨型高能气体开关的电极使用寿命分析

两电极气体开关是大型激光装置能源模块中开关元件的重要候选方案。分析石墨材料相比于传统金属材料烧蚀的特殊性。由于高能脉冲放电(转移电荷量大于25 C)时,石墨烧蚀质量损耗与转移电荷量呈线性关系,提出可用于评估电极使用寿命的烧蚀速率,并给出了实用的烧蚀速率测算方法。针对等电场面设计的石墨电极,提出表征石墨电极在使用过程中的电气寿命模型及相应的寿命终结判据,并对所研制的一种单次转移电荷量超过100 C的石墨型高能气体开关进行了寿命预测和试验验证。所得结论对石墨型高能气体开关的研制和使用具有参考意义。

直流与交流交联聚乙烯电缆料绝缘特性的差异及其机理分析

为研究交、直流电缆料绝缘特性的差异及其相关机理,对比测试了不同温度下交、直流电缆料的空间电荷和介电性能等主要绝缘特性,并通过红外光谱分析了造成差异的机理。研究结果表明:相比较交流电缆料,直流电缆料的空间电荷性能更优异、直流场下的击穿分散性更小但短时击穿场强稍低、杂质离子电导更少;红外光谱分析发现交、直流电缆料中羰基含量不同,而羰基含量表征了主链的完整程度和极性基团的含量,因此认为交直、流电缆料主链的完整程度和极性基团的含量是影响其绝缘性能差异的主要原因。

药型罩制造技术的发展

本文介绍了国内外药型罩制造技术的发展现状,对精密药型罩要求的精密成形工艺作了详细论述,同时概述了用于制造重金属药型罩的先进制造工艺及发展趋势。对未来药型罩的发展作了大胆的预测。

电动汽车无线充电系统磁场仿真与屏蔽技术研究

电动汽车无线充电系统工作过程中不可避免地会在车体周围产生一定的电磁辐射,这是用户对于电动汽车无线充电非常关注的一个安全问题。本文通过电路仿真和有限元仿真研究了千瓦级电动汽车无线充电系统额定工作时在车体内及充电装置周围产生的电磁场,进而对比了收发装置整体屏蔽和本文提出的只在发射端外沿施加水平或竖直屏蔽这三种屏蔽方式的屏蔽效果,研究结果表明:汽车底盘天然提供了较好的磁场屏蔽,车内电磁辐射较小;本文提出的在发射装置外沿加装水平屏蔽带的屏蔽方式,经济、高效、实用,适用于电动汽车无线充电系统。

应用Multi-Langmuir模型评价土壤的表面电荷特性

用返滴定技术测定土壤的可变电荷量(Qv),应用Muti-Langmuir模型评价土壤的表面电荷特性。结果表明,黄壤和黄棕壤可变电荷量的变化范围在0～45cmolkg-1,红壤为0～21cmolkg-1,砖红壤和赤红壤为0～14cmolkg-1。可变电荷量(Qv)依赖土壤悬液的pH,3点位模型能很好地描述6种土壤的可变电荷量随pH的变化关系;黄壤、黄棕壤、湖南红壤、江西红壤、赤红壤和砖红壤的pK1分别为4.45、4.46、4.76、4.62、4.66和4.74,可变电荷量Qv1分别为11.7、9.64、9.31、7.14、4.86和5.95cmolkg-1。黄壤和黄棕壤pK1较红壤、砖红壤和赤红壤约低0.3。pK1与ZPC呈现极显著的线性关系,可变电荷量(Qv(i))与有机质含量呈极显著的正相关。