基于OD矩阵的电动出租车充电负荷时空特性预测分析

电动出租车规模化发展带来的充电负荷是城市电网中的新型负荷。电动出租车充电负荷与其商业运营特点紧密相关。融合出租交通的OD矩阵信息和出租商业运营时间窗,分析乘客出行需求特征以及出租车行驶状态转换特征,采用蒙特卡洛法,建立出租交通充电需求模拟仿真流程。计及出租车载客和寻客状态行驶速度,以及出行路线和快、慢充电能补给方式决策上的差异性,量化仿真出租车运营随机性、分散性对充电需求时空分布的影响。以某城市电动出租车未来规模化推广为算例,预测电动出租充电需求时空分布,为该地区电动出租车充电网络及配电网规划提供支撑。     

气液两相流ERT系统图像边缘检测方法研究

为提高气液两相流ERT(Electrical Resistance Tomography-电阻层析成像)系统所重建图像的质量,提出了一种基于Canny算子的气泡边缘检测方法.实验结果表明,该方法能有效地检测出气液两相流中气泡的边缘,为进一步的ERT系统检测提供了借鉴.     

Ignition of hydrogen–air mixtures using pulsed nanosecond dielectric barrier plasma discharges in plane-to-plane geometry

Ignition of preheated (400–500 K) H₂–air mixtures at low pressures (80–100 torr) excited by pulsed nanosecond dielectric barrier discharges is investigated through experiments and simulations. Time resolved absolute OH concentration and temperature data are obtained using Laser Induced Fluorescence (LIF) technique. Ignition is achieved in the decaying plasma after a burst of discharge pulses (repetition rate 10–40 kHz), with the time delay inferred from sudden rise in OH^* emission. One-dimensional simulations are performed to obtain information about the plasma generated radicals and heat release across the discharge gap. A plasma fluid formulation is used with ions and neutral species at gas temperature, and electrons in non-equilibrium. An accurate reduced chemistry mechanism is developed through sensitivity analysis to expedite the plasma simulations. The model predictions show excellent agreement with experimental measurements, validating the numerical framework and chemistry data. The input pulse energy and ignition characteristics are found to be highly sensitive to uncertainties in dielectric properties. Ignition delay exhibits a threshold-like dependence on input plasma energy, and increases steeply as the number of pulses in the burst is reduced. The nanosecond plasma assisted ignition is achieved through a two-step process. Firstly, the burst of discharge pulses produce a large pool of radicals and provide an average temperature rise of ∼1–2 K/pulse. In the next step, if the temperature exceeds a threshold value of ∼700 K, significant heat release from partial fuel oxidation is triggered. The process becomes self-sustaining and the temperature continues to rise even after the plasma source is switched off, accelerating the conventional H₂–O₂ chain branching pathways and leading to ignition. We provide conclusive evidence of large volume ignition with nanosecond plasma as opposed to thermal ignition at a hot-spot. Ignition is first observed at the center of the discharge gap, but the kernel expands rapidly to the entire volume, except near walls where heat losses keep the temperature low. It is demonstrated that the ignition occurs independently at different locations due to local plasma chemistry effects and heat transport does not play a significant role.     

用于两相流流型显示和空隙率测量的电容层析成像技术

引　言两相流流型的实时显示和空隙率的在线测量对两相流系统的控制、运行乃至机理研究等均具有重要意义 ,一直是两相流领域中重要的研究方向 .现已提出多种实现流型显示和空隙率测量的方法 ,例如用于流型显示的核辐射线法和光学法 ,用于空隙率 (或浓度 )测量的机理估算法、核辐射线法、电学法、光学法、微波法、热学法和核磁共振法等 ,但是总的来讲还未能满足应用要求 ,实际应用的例子也较少[1] .电容层析成像 (ｅｌｅｃｔｒｉｃａｌｃａｐａｃｉｔａｎｃｅｔｏｍｏｇｒａｐｈｙ ,简记ＥＣＴ)技术由于可在不干扰流场的情况下获取反映两相流…     

基于ERT传感器和数据挖掘技术的空气水两相流空隙率测量(英文)

Based on an electrical resistance tomography(ERT) sensor and the data mining technology,a new voidage measurement method is proposed for air-water two-phase flow.The data mining technology used in this work is a least squares support vector machine(LS-SVM) algorithm together with the feature extraction method,and three feature extraction methods are tested:principal component analysis(PCA),partial least squares(PLS) and independent component analysis(ICA).In the practical voidage measurement process,the flow pattern is firstly identified directly from the conductance values obtained by the ERT sensor.Then,the appropriate voidage measurement model is selected according to the flow pattern identification result.Finally,the voidage is calculated.Experimental results show that the proposed method can measure the voidage effectively,and the measurement accuracy and speed are satisfactory.Compared with the conventional voidage measurement methods based on ERT,the proposed method doesn’t need any image reconstruction process,so it has the advantage of good real-time performance.Due to the introduction of flow pattern identification,the influence of flow pattern on the voidage measurement is overcome.Besides,it is demonstrated that the LS-SVM method with PLS feature extraction presents the best measurement performance among the tested methods.     

一种带失真抵消的高增益低噪声放大器

提出了一种用于GPS/BD双频接收机的带失真抵消的低噪声放大器。采用部分源级电感简并结构,相较于传统全部源级简并结构,以极低代价提高了增益。通过噪声特性的理论分析,优化了噪声系数,给出了相应的参数公式。通过增加失真抵消结构,提高了电路的线性度。采用TSMC 0.18 μm CMOS工艺进行设计。仿真结果表明,该放大器的增益达18 dB,噪声系数为1.7 dB,输入3阶交调截点为-1.4 dBm。在电源电压为1.8 V时,消耗电流为4.7 mA。相比传统结构,该放大器的增益提高了2 dB,线性度提高了6 dBm,功耗提高了15%。     

基于全集成自动化（TIA）的型钢生产线堆垛机磁头控制

为了使型钢堆垛机磁头供电装置具备当代TIA全集成自动化特性，本文利用西门子直流调速6RA70装置，为磁头特低压供电，控制型钢堆垛机磁头电流，实现磁头的激磁、保磁、去磁过程，同时通过DriveESPCS7工程师站对6RA70装置组态、参数化，实现TIA全集成自动化。     

Electrospinning Derived One‐Dimensional LaOCl: Ln3+ (Ln = Eu/Sm,Tb, Tm) Nanofibers,Nanotubes and Microbelts with Multicolor‐Tunable Emission Properties

One‐dimensional LaOCl: Ln³⁺ (Ln³⁺ = Eu³⁺/Sm³⁺, Tb³⁺, Tm³⁺) nanofibers, nanotubes, and quasi‐1D microbelts are successfully prepared by a sol–gel/electrospinning process. XRD, FT‐IR, SEM, TEM, as well as photoluminescence (PL) and cathodoluminescecne (CL) spectra are used to characterize the resulting samples. Through a heat treatment process at high temperature, the as‐prepared samples are well‐crystallized with the tetragonal structure of LaOCl. Under ultraviolet radiation and low‐voltage electron beam excitation, the LaOCl: Eu³⁺, LaOCl:Sm³⁺, LaOCl: Tb³⁺, and LaOCl: Tm³⁺ samples give the characteristic transitions of Eu³⁺ (⁵D_{0, 1, 2} → ⁷F_{0, 1, 2, 3, 4}), Sm³⁺ (⁴G_5/2 → ⁶H_{5/2, 7/2, 9/2}), Tb³⁺ (⁵D_{3, 4} → ⁷F_{2, 3, 4, 5, 6}), and Tm³⁺ (¹D₂, ¹G₄ → ³F₄, ³H₆), respectively. Moreover, there exists simultaneous luminescence of Tb³⁺, Tm³⁺, Eu³⁺, or Sm³⁺ individually when codoping them in the single‐phase LaOCl host (for example, LaOCl: Tb³⁺, Eu³⁺/Sm³⁺; LaOCl: Tm³⁺, Eu³⁺/Sm³⁺; LaOCl: Tb³⁺, Tm³⁺, Eu³⁺/Sm³⁺ systems), which is beneficial to tune the emission colors. Under low‐voltage electron beam excitation (1–5 kV), a variety of colors can be efficiently adjusted in a wide triangle region enveloped by three CIE chromaticity coordinate points [LaOCl:Eu³⁺, (x = 0.6039, y = 0.3796); LaOCl: Tb³⁺, (x = 0.2452, y = 0.5236); LaOCl: Tm³⁺, (x = 0.1456, y = 0.0702)] for mono‐ and co‐doped LaOCl: Ln³⁺ (Eu³⁺, Sm³⁺, Tb³⁺, Tm³⁺) samples, making these materials have potential applications in field‐emission display devices.     

Enhanced Antitumor Efficacy by 808 nm Laser‐Induced Synergistic Photothermal and Photodynamic Therapy Based on a Indocyanine‐Green‐Attached W18O49 Nanostructure

A novel nanoplatform based on tungsten oxide (W₁₈O₄₉, WO) and indocyanine green (ICG) for dual‐modal photothermal therapy (PTT) and photodynamic therapy (PDT) has been successfully constructed. In this design, the hierarchical unique nanorod‐bundled W₁₈O₄₉ nanostructures play roles in being not only as an efficient photothermal agent for PTT but also as a potential nanovehicle for ICG molecules via electrostatic adsorption after modified with trimethylammonium groups on their surface. It is found that the ability of ICG to produce cytotoxic reactive oxygen species for PDT is well maintained after being attached on the WO, thus the as‐obtained WO@ICG can achieve a synergistic effect of combined PTT and PDT under single 808 nm near‐infrared (NIR) laser excitation. Notably, compared with PTT or PDT alone, the enhanced HeLa cells lethality of the 808 nm laser triggered dual‐modal therapy is observed. The in vivo animal experiments have shown that WO@ICG has effective solid tumor ablation effect with 808 nm NIR light irradiation, revealing the potential of these nanocomposites as a NIR‐mediated dual‐modal therapeutic platform for cancer treatment.