基于BLE和Wi-Fi的建筑能耗监测系统设计

针对传统建筑能耗监测系统存在采集单元功耗高和布线复杂的问题,设计了一种低功耗的无线监测系统。所设计的监测系统包括采集单元、集中器、监测中心和通信网络四部分。其中：采集单元主要由计量电路和BLE（Bluetooth low energy,低功耗蓝牙）通信电路组成,其通过计量电路采集用电设备的能耗数据,并通过BLE通信电路将处理好的能耗数据发送至集中器;集中器主要由BLE通信电路和Wi-Fi通信电路组成,其通过BLE通信电路接收采集单元计量的能耗数据并进行整合、处理,然后通过Wi-Fi通信电路将能耗数据转发至监测中心;监测中心采用B/S（browser/server,浏览器/服务器）架构进行设计,其通过监测界面显示能耗数据并将数据保存在数据库中。所设计的监测系统通过采用BLE和Wi-Fi的通信方式降低了采集单元的运行功耗和布线复杂度,并延长了通信距离;基于B/S架构设计的监测中心可实现跨平台运行,提高了系统的灵活性。测试结果表明,所设计的监测系统的计量偏差率低于5%,通信成功率高于98%,且能够及时监测用电设备的耗能状况,具有较高的实用价值。     

Impact of induction hardened workpiece hardness on EDM performance

The objective of this research work is to correlate the impact of thermally induced workpiece hardness with electric discharge machining (EDM) performances and establishment of the modified property responsible for the deviation in change in behavior of output responses in sinking electrical discharge machining process. The response surface methodology with central composite design approach was applied with four controllable input parameters such as pulse-on-time (T_on), pulse-off time (T_off), peak current (I_P), and gap voltage (V) for experimental comparative study. In this current analysis, material removal rate, tool wear rate, and energy density were chosen as the desired response variables. It was observed that change in hardness through induction thermal hardening process of the base alloy had a predominant effect on the change in output responses such as material removal rate, tool wear rate, and energy density with strong confirmation. The modified electrical property associated with enhanced workpiece hardness was primarily responsible for alteration in EDM process behaviors. This preliminary assessment for the deviation in the performance of the EDM process with respect to change in hardness will be quite useful for the control settings in the job shop production planning for processing and modifying properties of induction hardened alloy steels.     

Multi-objective component sizing of a power-split plug-in hybrid electric vehicle powertrain using Pareto-based natural optimization machines

The urgent need to meet increasingly tight environmental regulations and new fuel economy requirements has motivated system science researchers and automotive engineers to take advantage of emerging computational techniques to further advance hybrid electric vehicle and plug-in hybrid electric vehicle (PHEV) designs. In particular, research has focused on vehicle powertrain system design optimization, to reduce the fuel consumption and total energy cost while improving the vehicle's driving performance. In this work, two different natural optimization machines, namely the synchronous self-learning Pareto strategy and the elitism non-dominated sorting genetic algorithm, are implemented for component sizing of a specific power-split PHEV platform with a Toyota plug-in Prius as the baseline vehicle. To do this, a high-fidelity model of the Toyota plug-in Prius is employed for the numerical experiments using the Autonomie simulation software. Based on the simulation results, it is demonstrated that Pareto-based algorithms can successfully optimize the design parameters of the vehicle powertrain.     

电力负荷用户终端

电力负荷用户终端是融合通信，传输，计算机等高新技术以及供电技术对供电部所辖用户的用电情况进行实时监测，控制，管理的系统。该系统以单片机为核心，组成了集信号采集，电量监测，数据处理，拉闸控制等技术为一体的智能仪器。     

Enhanced large field-induced strain and energy storage properties of Sr0.6La0.2Ba0.1TiO3-modified Bi0.5Na0.5TiO3 relaxor ceramics

Dielectric materials especially relaxor ferroelectrics with giant strain and super-high energy density have received substantial attentions. Bi_0.5Na_0.5TiO₃ (BNT)-based ceramics as one of the typical relaxor ferroelectric materials have been extensively explored for their distinctive performance. Here, lead-free (1?x)Na_0.5Bi_0.5TiO₃–xSr_0.6La_0.2Ba_0.1TiO₃ (BNT–SLBT) ceramics were designed and prepared by the solid-state reaction method. A large strain response of 0.470% and huge piezoelectric strain coefficient of 600 pm/V were achieved in BNT–0.15SLBT relaxor, which were attributed to the relaxor-ferroelectric phase transition under stimulated electric field. The ε_r–T curve shows that with the increase of x content, the phase transition temperature moves to room temperature, which improves the energy storage performance. A super-high recoverable energy density W_rec of 3.18 J/cm³ and η of 82.8% under 250 kV/cm can be achieved in BNT–0.25SLBT ergodic relaxor. Moreover, the charge–discharge properties characterized by a high pulse discharge energy density (0.816 J/cm³), a rapid discharge duration (3 μs) and a power density (2.86 MW/cm³) are also observed in BNT–0.25SLBT ceramic. We provide a method for enhanced BNT-based ceramics with strain and energy storage in drive device or capacitor, facilitating the exploration of ceramic in the future.

     

The parameters of nonequilibrium microwave discharge in nitrogen in a tube in a rectangular waveguide

Computer codes are developed for the processing of emission spectra of nonequilibrium plasma in nitrogen for the purpose of obtaining information about the translational T _g and rotational T _rot temperatures, the populations of vibrational levels in the ground electron and electron-excited states, the electron energy distribution function, the electron concentration N _e , and the electric field intensity E. The computer codes are used to determine the parameters of microwave-discharge plasma in nitrogen in discharge systems of two types, namely, in a discharge tube (with a radius of 1 cm), which crosses a rectangular waveguide (plasmatron on the H ₁₀ wavelength, at a pressure of 1.7 torr and absorbed power density of 1.5 W/cm³), and in a discharge section of similar structure on the basis of prismatic resonator (at a pressure of 1.0 torr and absorbed power density of 0.4 W/cm³). The mechanisms of population of the N₂(C ³Π_u) state are treated.     

Post processing of the layer deposited by electric discharge coating

Electric discharge coating is a deposition process that can deposit thin and thick films using electric discharge machine. In the present experimental investigation, W–Cu powder metallurgical electrodes of 325 mesh size have been used as electrodes for the deposition process. This work focuses on the post processing of deposited layer to alter the surface characteristics. Two different methods have been attempted to reduce the surface roughness. The results demonstrate the possibility of enhancing the surface finish with these methods. XRD analysis substantiates the presence of the tool materials and their carbides such as Cu, W, WC, and W₂C as the major constituents in the deposited layer.     

Powering up the Future: Radical Polymers for Battery Applications

Our society's dependency on portable electric energy, i.e., rechargeable batteries, which permit power consumption at any place and in any time, will eventually culminate in resource wars on limited commodities like lithium, cobalt, and rare earth metals. The substitution of conventional metals as means of electric charge storage by organic and polymeric materials, which may ultimately be derived from renewable resources, appears to be the only feasible way out. In this context, the novel class of organic radical batteries (ORBs) excelling in rate capability (i.e., charging speed) and cycling stability (>1000 cycles) sets new standards in battery research. This review examines stable nitroxide radical bearing polymers, their processing to battery systems, and their promising performance.     

Superconductivity in Doped Systems Beyond Migdal's Theorem

The basic system of equations for a theory of superconductivity in systems with a chaotically distributed paramagnetic impurity of substitution, in which Migdal theorem is violated (it cannot be supposed ω₀ ? E _F), is presented. We take into account electron–phonon and impurity diagrams as well as supplement ones corresponding to intersection of electron–phonon and electron–impurity lines. Decrease of the quantity T _C with increase of impurity concentration is shown to weaken in comparison with the case of usual superconductors. Coefficient of isotope effect α, energy gap, and order parameter at T = 0 are also calculated. Behavior of these quantities as a function of impurity concentration depends on Migdal's parameter m and transferred momentum q _c.     

A Non-Contact Original-State Online Real-Time Monitoring Method for Complex Liquids in Industrial Processes

Failures are very common during the online real-time monitoring of large quantities of complex liquids in industrial processes, and can result in excessive resource consumption and pollution. In this study, we introduce a monitoring method capable of non-contact original-state online real-time monitoring for strongly coated, high-salinity, and multi-component liquids. The principle of the method is to establish the relationship among the concentration of the target substance in the liquid (C), the color space coordinates of the target substance at different concentrations (L¹, a¹, b¹), and the maximum absorption wavelength (λ_max); subsequently, the optimum wavelength λ_T of the liquid is determined by a high-precision scanning-type monitoring system that is used to detect the instantaneous concentration of the target substance in the flowing liquid. Unlike traditional monitoring methods and existing online monitoring methods, the proposed method does not require any pretreatment of the samples (i.e., filtration, dilution, oxidation/reduction, addition of chromogenic agent, constant volume, etc.), and it is capable of original-state online real-time monitoring. This method is employed at a large electrolytic manganese plant to monitor the Fe³⁺ concentration in the colloidal process of the plant’s aging liquid (where the concentrations of Fe³⁺, Mn²⁺, and (NH₄)₂SO₄ are 0.5–18 mg·L⁻¹, 35–39 g·L⁻¹, and 90–110 g·L⁻¹, respectively). The relative error of this monitoring method compared with an off-line laboratory monitoring is less than 2%.     

Approximation of experimental constants of chemical reaction rates in a wide temperature range

This article discusses possible methods of approximation of constants of chemical reaction rates onto a region of values that is beyond the limits of the experimental temperature range. In particular, this work studies direct approximation of constants of chemical reaction rates obtained upon processing of experimental values, approximation based on an analytical simulated dependence of the integral cross section of the process on energy, and approximation based on direct solution of the equation for constants of the chemical reaction rates at an arbitrary dependence of the process integral cross section on energy. The integral equation has been solved using the Tikhonov regularization. It is shown that this approach makes it possible to determine the threshold energy as well as to recover the form of the cross section. A second-order reaction CH₄ → CH₃ + H has been considered, the activation energy of which is 44560 K. Based on the calculation for the temperature range of 10000–50000 K, the following approximation can be recommended: 5.04 × 10^?6 T ^?1.5 exp(?45377/T), cm^?3/s. The obtained data can be applied for various calculations, in particular, in problems of hypersound gas dynamics, as well as for filling databases.     

工业锅炉能耗在线监测作用及其应用的分析

目前我国工业锅炉总体能源浪费情况严重,与企业节能管理及锅炉运行中诸多因素密切相关。近年来福建省建立了能源计量数据公共平台,积极开展重点耗能企业工业锅炉能耗数据监测工作。研发工业锅炉节能监测及诊断系统并实施运用,已取得明显实效。本文通过对锅炉能耗现状、能耗数据监测作用的探讨,提出相应的建议。     

Rotational temperature of oxygen molecules in DC glow discharge in O2-Ar mixtures sustained in discharge tube made from Pyrex glass

The active DC glow discharge sustained in pure O₂ and O₂-Ar mixtures with Ar/O₂ concentration ratios up to 50% has been studied in a Pyrex discharge tube for pressures up to 500 Pa and for discharge currents up to 40 mA. The electric field strength and emission spectra parameters of the discharge were studied by means of the double-probe method and optical emission spectroscopy.The electric field strength was found to increase with the pressure and decrease with the discharge current, which is typical for DC glow discharges. Considering O₂-Ar mixtures, the values of electric field strength decreased with Ar/O₂ ratio.We have focused on the emitted radiation. The rotational temperature T_rot of molecular oxygen was determined from the well-resolved atmospheric A-band at 760 nm. The increase of the rotational temperature with increasing deposited power has been observed for all studied Ar/O₂ ratios. Moreover, it has been found that values of T_rot are independent of the mixture composition.     

Influence of a Weak Magnetic Field on Photoconductivity Spectrum of C60 Single Crystal

Abstract

Comparative research of the excitation photoconductivity spectra (quantum light energy 2–5 eV) of C₆₀ single crystal in and out of magnetic field at the temperature T = 250–350 K has been carried. The spectral evolution at this temperature range is described. It is shown that the spectra changes abrupt at temperature T ₁ ～ 260 K and T ₂ ～ 315 K. An increase in the photoconductivity up to 15% was observed in the magnetic field (B = 0.4 T) within the photon energy range 2.5–4.5 eV. Local photoconductivity peak's appearances in the magnetic field have been proven that the charge transfer excitons take part in a photoconductivity.     

Conserving energy by optimizing the heat exchanger networks of glyphosate production with pinch technology

China is one of the largest glyphosate producers in the world. The production process consumes a large amount of energy and discharges a huge volume of wastewater. In the glyphosate production system, the by-product recovery process consumes the largest amount of energy. To conserve energy consumption and minimize wastewater discharge, the study applies pinch technology to optimize the heat exchanger network of the by-product recovery subsystem. The results show that the optimal temperature for the process is 8°C. Theoretically, the optimized heat exchanger network has the potential to reduce the annual consumption of steam, condensed water, and the freshwater resource by 1.53, 26.84 and 56.72%, respectively, when compared with current consumption levels. At the same time, the total annual cost can be reduced by 100,000 dollars per year, which means that the optimization can achieve the win–win objective of the economic and environmental benefits in the glyphosate production process.     

Effects of LiF/Al back electrode on the amorphous/crystalline silicon heterojunction solar cells

To improve the quantum efficiency (QE) and hence the efficiency of the amorphous/crystalline silicon heterojunction solar cell, we have employed a LiF dielectric layer on the rear side. The high dipole moment of the LiF reduces the aluminum electrode's work–function and then lowers the energy barrier at back contact. This lower energy barrier height helps to enhance both the operating voltage and the QE at longer wavelength region, in turn improves the open-circuit voltage (V_oc), short-circuit current density (J_sc), and then overall cell efficiency. With optimized LiF layer thickness of 20 nm, 1 cm² heterojunction with intrinsic thin layer (HIT) solar cells were produced with industry-compatible process, yielding V_oc of 690 mV, J_sc of 33.62 mA/cm², and cell efficiencies of 17.13%. Therefore LiF/Al electrode on rear side is proposed as an alternate back electrode for high efficiency HIT solar cells.     

Bamboo‐Like Nitrogen‐Doped Carbon Nanotube Forests as Durable Metal‐Free Catalysts for Self‐Powered Flexible Li–CO2 Batteries

The Li–CO₂ battery is a promising energy storage device for wearable electronics due to its long discharge plateau, high energy density, and environmental friendliness. However, its utilization is largely hindered by poor cyclability and mechanical rigidity due to the lack of a flexible and durable catalyst electrode. Herein, flexible fiber‐shaped Li–CO₂ batteries with ultralong cycle‐life, high rate capability, and large specific capacity are fabricated, employing bamboo‐like N‐doped carbon nanotube fiber (B‐NCNT) as flexible, durable metal‐free catalysts for both CO₂ reduction and evolution reactions. Benefiting from high N‐doping with abundant pyridinic groups, rich defects, and active sites of the periodic bamboo‐like nodes, the fabricated Li–CO₂ battery shows outstanding electrochemical performance with high full‐discharge capacity of 23 328 mAh g^?1, high rate capability with a low potential gap up to 1.96 V at a current density of 1000 mA g^?1, stability over 360 cycles, and good flexibility. Meanwhile, the bifunctional B‐NCNT is used as the counter electrode for a fiber‐shaped dye‐sensitized solar cell to fabricate a self‐powered fiber‐shaped Li–CO₂ battery with overall photochemical–electric energy conversion efficiency of up to 4.6%. Along with a stable voltage output, this design demonstrates great adaptability and application potentiality in wearable electronics with a breath monitor as an example.     

A Fast Charging–Cooling Coupled Scheduling Method for a Liquid Cooling-Based Thermal Management System for Lithium-Ion Batteries

Efficient fast-charging technology is necessary for the extension of the driving range of electric vehicles. However, lithium-ion cells generate immense heat at high-current charging rates. In order to address this problem, an efficient fast charging–cooling scheduling method is urgently needed. In this study, a liquid cooling-based thermal management system equipped with mini-channels was designed for the fast-charging process of a lithium-ion battery module. A neural network-based regression model was proposed based on 81 sets of experimental data, which consisted of three sub-models and considered three outputs: maximum temperature, temperature standard deviation, and energy consumption. Each sub-model had a desirable testing accuracy (99.353%, 97.332%, and 98.381%) after training. The regression model was employed to predict all three outputs among a full dataset, which combined different charging current rates (0.5C, 1C, 1.5C, 2C, and 2.5C (1C = 5 A)) at three different charging stages, and a range of coolant rates (0.0006, 0.0012, and 0.0018 kg·s⁻¹). An optimal charging–cooling schedule was selected from the predicted dataset and was validated by the experiments. The results indicated that the battery module’s state of charge value increased by 0.5 after 15 min, with an energy consumption lower than 0.02 J. The maximum temperature and temperature standard deviation could be controlled within 33.35 and 0.8 °C, respectively. The approach described herein can be used by the electric vehicles industry in real fast-charging conditions. Moreover, optimal fast charging–cooling schedule can be predicted based on the experimental data obtained, that in turn, can significantly improve the efficiency of the charging process design as well as control energy consumption during cooling.     

Study on the Physical and Electrical Properties of Bi2 − δZnδSr2Ca2Cu3O10 + y Glass-Ceramic Superconductors

We have fabricated a series of glass-ceramic (Bi_{2 ? δ}Zn_δ) Sr₂Ca₂Cu₃O_{10 + y} , where δ = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0, and investigated the effect of Zn ions on the glass formation, crystallization, thermal, electrical, and on the magnetic properties of the BSCCO-2223 superconductor system. The structural symmetry was found to be tetragonal in all the substitution levels. The best electrical performance was obtained from the δ = 0 sample, the T _c and T _zero was obtained at 110 K and 107 K, respectively. The J _c values of the samples were determined using the magnetization hysteresis and Bean's model. The crystallization kinetics were investigated using nonisothermal models of Augis–Bennett. The calculated activation energy, E _a, of the system was found to be in the range of 258–336 kJ/mol.