Cost-Effective Monitoring of the Fuel Air Equivalence-Ratio with a Lambda Sensor and a Microcontroller in a Downdraft Biomass Gasifier

The operation of biomass treatment devices such as gasifiers is based on the control of key parameters that play an important role in product formation. These include: temperature, excess oxygen, relative humidity and biomass composition. This work focuses on excess oxygen and temperature. Unfortunately, flue gas oxygen analyzers are expensive and not accessible to small industries. However, the equivalence ratio is linked to excess oxygen and has the advantage of not depending on biomass composition. This study therefore focuses on the design and development of a device for controlling this equivalence ratio by measuring oxygen concentration using a self-propelled Lambda probe, and a system for monitoring this equivalence ratio using an Arduino Uno 3 microcontroller. The temperature is recorded with an accuracy of ±1.5°C. For a heating time of 10 minutes, the response time to temperature change is around 3 seconds, which is sufficient for the device to function properly. This simple device is an efficient and cost-effective means of checking the equivalence ratio.

From“Semantic Equivalence”to“Verve Reproduction”—Exploration on Xu Yuanchong’s English Translation of the Analects

This paper focuses on the English translation of Xu Yuanchong’s Analects,explains in depth the theory of semantic equivalence and the theory of verve reproduction.It analyzes the application and integration of these two theories by Xu Yuanchong in detail.Through a comprehensive textual analysis,this paper summarizes the remarkable achievements of the English translation of the Analects,such as the accurate transmission of semantics and the vivid reproduction of cultural charm,which is expected to bring new thinking directions and valuable references to the study of the English translation of the Analects.

Special Relativity’s “Newtonization” in Complex “Para-Space”: The Two Theories Equivalence Question

Complex model, say C3, of “para-space” as alternative to the real M4 Minkowski space-time for both relativistic and classical mechanics was shortly introduced as reference to our previous works on that subject. The actual aim, however, is an additional analysis of the physical and para-physical phenomena’ behavior as we formally transport observable mechanical phenomena [motion] to non-real interior of the complex domain. As it turns out, such procedure, when properly set, corresponds to transition from relativistic to more classic (or, possibly, just classic) kind of the motion. This procedure, we call the “Newtonization of relativistic physical quantities and phenomena”, first of all, includes the mechanical motion’s characteristics in the C3. The algebraic structure of vector spaces was imposed and analyzed on both: the set of all relativistic velocities and on the set of the corresponding to them “Galilean” velocities. The key point of the analysis is realization that, as a matter of fact, the relativistic theory and the classical are equivalent at least as for the kinematics. This conclusion follows the fact that the two defined structures of topological vector spaces i.e., the structure imposed on sets of all relativistic velocities and the structure on set of all “Galilean” velocities, are both diffeomorphic in their topological parts and are isomorphic as the vector spaces. As for the relativistic theory, the two approaches: the hyperbolic (“classical” SR) with its four-vector formalism and Euclidean, where SR is modeled by the complex para-space C3, were analyzed and compared.

Characteristic analysis of scattering field in two-layer media by Green's function

The problem of three-dimensional(3D) acoustic scattering in a complex medium has aroused considerable interest of researchers for many years. An ultrasonic scattered field calculating technique is proposed to study the scattering echo from strongly scattered materials in a two-layer medium in this work. Firstly, with the high frequency stationary phase method,the Green's function of two-layer fluid media is derived. And then based on the idea of integral equation discretization,the Green's function method is extended to two-layer fluid media to derive the scattering field expression of defects in a complex medium. With this method, the scattering field of 3D defect in a two-layer medium is calculated and the characteristics of received echoes are studied. The results show that this method is able to solve the scattering P wave field of 3D defect with arbitrary shape at any scattering intensity in two-layer media. Considering the circumstance of waterimmersion ultrasonic non-destructive test(NDT), the scattering sound field characteristics of different types of defects are analyzed by simulation, which will help to optimize the detection scheme and corresponding imaging method in practice so as to improve the detection quality.

Promoting the International Dissemination of Chinese Culture Through International Chinese Language Education: A Case Study of Chinese-English Idiomatic Equivalence

One major task of our improvement of China’s international communication capabilities is to tell China’s stories well and make China’s voice heard to communicate a comprehensive,multi-dimensional view of China in the international arena.International Chinese language education bears the dual responsibility of spreading the Chinese language and promoting the Chinese culture.How to shape global narratives for telling China’s stories and improve China’s international communication capabilities has become an important issue that concerns international Chinese language education.Chinese idioms,which are hidden treasures of the Chinese language,can play a unique role in this regard.It is therefore necessary to review the content and methods of including idioms in international Chinese language education.In this paper,instruction in idioms is approached by making a corpus-based comparative analysis from the theoretical perspectives of equivalence,cognitive metaphor,and second language acquisition.Qualitative and quantitative methods are combined to analyze idioms to be added to the vocabulary of international Chinese language education in three dimensions:word frequency,semantic transparency,and functional equivalence.This paper aims to explore a new approach to the dissemination of Chinese culture through instruction in idioms in international Chinese language education.

A Physical Interpretation of Mass-Energy Equivalence Based on the Orthogonal Collision

Einstein described the mass-energy equivalence as the most important result of special relativity. But more than a century after Einstein first derived the relationship between mass-energy equivalence (or mass-energy equation), questions left for people are how to understand that mass and energy are somehow equivalent, and how to give the dynamical process for the conversion from mass to energy (or vice versa). This paper first interprets the formula of mass-energy equivalence published by Einstein in 1905, and then gives the equivalence relationship of mass-energy transition based on the dynamics of particle orthogonal collision. As a result, the orthogonal collision of two high-energy mass particles can generate a huge mass-energy density, equivalent to the total energy of N new particles, which is a one-way dynamic process that generates new mass-energy density and new matter. This conversion of mass into energy has nothing to do with special relativity.

基于结构响应的舱室内爆TNT等效方法

[目的]旨在揭示爆轰产物后燃烧效应对封闭空间中爆炸载荷的影响规律。[方法]通过往封闭舱室中充入氮气来抑制爆轰产物燃烧,开展在空气和氮气两种不同气体环境下封闭舱室内TNT爆炸响应试验,记录温度、压力变化历程和靶板中心点残余挠度,建立基于无量纲载荷参数的靶板变形与炸药释放能量之间的关系,并提出考虑后燃烧效应的封闭空间TNT等效方法。[结果]结果发现,由于爆轰产物燃烧能量释放量不同,在氮气环境中,封闭空间内爆炸压力、温度和靶板动态响应明显低于空气环境。内爆载荷分析需计入TNT爆炸产物燃烧释放的能量及其增强效应。[结论]与现有基于准静态压力的TNT当量计算方法进行的比较表明,所提基于结构响应的舱室内爆TNT等效方法具有合理性和良好的适用性。

城乡等值化视角下旅游驱动乡村治理的理论逻辑与作用机制

乡村旅游是乡村振兴的重要路径,而乡村治理又是乡村振兴的核心内容.通过旅游驱动乡村治理已在实践层面和理论研究中受到持续关注,但是对其理论逻辑和作用机制的探究还有待深化.该文基于城乡等值化视角,分析旅游驱动城乡要素流动改善乡村治理的理论逻辑和作用机制.研究发现:1)乡村旅游能够打破乡村治理的边界,桥接城乡要素的流动,通过促进城乡要素的双向循环流动来推动乡村治理;2)在城乡等值化背景下,乡村旅游通过调整土地、人才、资本、文化、生态、技术等城乡要素的流动状态,在乡村治理层面形成响应,进而助推达成乡村经济、社会、文化、生态、政治等多元治理目标;3)应根据乡村旅游发展实际,将其置于城乡协调发展的整体框架下,旅游驱动乡村治理的积极贡献才能最大地发挥出来.

计及低电压穿越及故障全过程动态的双馈风电场等值方法

在分析双馈感应发电机(DFIG)故障各阶段动态的基础上,提出了一种计及低电压穿越控制的双馈风电场等值方法。首先,讨论了低电压穿越控制策略,给出了含双馈风电场的电力系统故障稳态潮流计算方法。在考虑电压暂态过程的条件下,分析了外部系统短路故障后DFIG转子电流的变化机理,指出电压跌落深度及风电功率是影响短路电流的主要因素,可根据动作分界线判断撬棒是否动作。然后,根据初始风速及撬棒状态将风电场中的DFIG分为3群,并对等值DFIG及集电网络进行聚合。为提高等值模型在恢复阶段的精度,根据故障稳态电压对双馈风电场功率恢复曲线进行预估,并在此基础上对等值DFIG恢复速率进行分段修正。最后,对含双馈风电场的算例系统进行了等值计算。仿真结果表明,等值模型较好地保持了原系统在故障各阶段的动态,在保持较高精度的前提下有效简化了系统,提高了计算速度。

基于电路等效的并网逆变器失稳分析与稳定控制

以并网逆变器为功率接口的新能源发电系统在弱电网条件下易发生振荡失稳问题。该文将并网逆变器的控制回路可视化为电路元件组成的虚拟阻抗,基于该电路模型分析了弱电网条件下电流内环与锁相环交互作用导致并网逆变器振荡失稳的机理,在此基础上,提出了基于有源阻尼的稳定控制设计方法,并对不同有源阻尼控制的电路特性以及稳定性提升能力进行了对比分析。研究结果表明,针对锁相环引入负电阻造成的振荡失稳问题,阻抗-高通滤波器型有源阻尼控制策略具有更优的稳定性提升能力。最后通过PSCAD/EMTDC仿真和远宽StarSim控制器硬件在环实验对比了不同有源阻尼控制策略的振荡抑制效果,并验证了阻抗-高通滤波器型有源阻尼控制的动态性能。结果表明,所设计的稳定控制能够在200 ms内有效抑制系统振荡,并且可实现在短路比为1的极弱电网条件下稳定运行。

无刷双馈电机研究综述与展望

无刷双馈电机具有结构可靠、变频器容量小等优势,非常适合灵活运行于防爆、易燃等特殊或极端工况,近年来受到广泛关注。该文根据无刷双馈电机的基本工作原理,明确了该类电机的命名原则与规范名称;总结了现有定转子方案的结构及性能特点,综合考虑性能指标与结构工艺,提出了转子双套绕组的发展方向;梳理了无刷双馈电机的稳态等效电路模型及基于各类数学模型的优化设计方法,针对现存难以完整考虑不同转速工况性能的不足,阐明了利用新型同步-异步相串联等效电路进行优化设计的思路;对比分析了经典及新近出现的无刷双馈电机控制系统拓扑和控制策略特点,面向典型电动、发电工况建立了完整的电机及控制系统。最后,对无刷双馈电机的上述理论研究问题及工业应用的发展方向进行了总结阐述,为该类电机的深入研究及加快推广应用提供参考和指导。

CMIP6模式对欧亚大陆冬季雪水当量的模拟能力评估及未来预估

基于第六次耦合模式比较计划(CMIP6)的模式模拟数据和欧洲宇航局GlobSnow卫星遥感雪水当量(Snow Water Equivalent,SWE)资料,评估了CMIP6耦合模式对1981~2014年欧亚大陆冬季SWE的模拟能力,并应用多模式集合平均结果预估了21世纪欧亚大陆SWE的变化情况。结果表明,CMIP6耦合模式对冬季欧亚大陆中高纬度SWE空间分布具有较好的再现能力,能模拟出欧亚大陆中高纬度SWE的主要分布特征;耦合模式对SWE变化趋势及经验正交函数主要模态特征的模拟能力存在较大差异,但多模式集合能提高模式对SWE变化趋势和主要时空变化特征的模拟能力;此外,多模式集合结果对欧亚大陆冬季SWE与降水、气温的关系也有较好的再现能力。预估结果表明,21世纪欧亚大陆东北大部分地区的SWE均要高于基准期(1995~2014年),而90°E以西的欧洲大陆SWE基本上呈现减少的特征;21世纪早期,4种不同排放情景下积雪变化的差异不大,但21世纪后期积雪变化的幅度差异较大,而且排放越高积雪变化的幅度越大,模式不确定性也越大;进一步的分析表明,欧亚大陆冬季未来积雪变化特征的空间分布与全球变化背景下局地气温、降水的变化密切相关,高温高湿的条件有利于欧亚大陆东北部积雪的增多。

基于动态相量的LCC-HVDC输电系统等值技术评述

立足于逆变侧换流站受端交流母线看向送端的基于电网换相换流器的高压直流输电(high-voltagedirectcurrent basedlinecommutedconverter,LCC-HVDC)系统的单端等值,对于优化设计继电保护、安稳控制和直流控保具有重要意义。为了同时获取计算的高精确性和实时性,动态相量模型以牺牲较低的仿真精度换取计算速度的提升,是实现LCC-HVDC输电线路双端等值的重要方式,但是用于LCCHVDC输电系统单端等值还存在难以平衡等值精度和计算速度的问题。针对该问题,该文分析了基于动态相量的LCCHVDC输电系统等值的应用价值、需求及难点,分别从等值计算模型中的提前触发角计算、换相重叠角计算、换相失败的判别及其对开关函数的影响和信号调制等4个因素评述现有研究现状及存在的问题,并提出了后续的研究建议。

沥青质颗粒在垂直井筒中的运移特征流速

为防止沥青质沉积堵塞油井,需明确垂直井筒内流体携沥青质颗粒运移特性。通过静态沉降试验探究不规则形状沥青质颗粒沉降末速规律,采用垂直井筒液携固流动试验装置研究不同因素对沥青质运移临界流速的影响程度,建立沥青质颗粒沉降末速和运移临界流速计算公式。结果表明:沥青质表面不均匀性增大了沉降阻力,使沉降等效直径小于颗粒实测粒径;运移临界流速与颗粒粒径成正比、与液相黏度成反比,颗粒体积分数对运移临界流速影响较小;相同条件下流体携沥青质运移临界流速为沉降末速的1.182倍。

基于正弦函数拟合的高动态捷联惯导姿态更新算法

为提高捷联惯导在高动态条件下的姿态解算精度,基于等效旋转矢量泰勒级数展开法,提出一种基于正弦函数拟合的高动态捷联惯导姿态更新算法。以正弦函数拟合载体运动角速度,考虑Bortz方程高阶项的影响,对陀螺角增量表示的旋转矢量进行泰勒六阶展开,对比旋转矢量不同形式表达式求得误差补偿系数。在MATLAB平台上,以圆锥运动与大角速率转动并存环境作为仿真条件,对所提算法与传统算法进行对比仿真分析。仿真结果表明,在小半锥角低频圆锥运动伴随高速角速率转动情况下,所提算法性能较好,当半锥角为0.5°、角频率为2.26πrad/s、常值角速率为5.30 rad/s、姿态解算周期为0.02 s时,所提正弦函数拟合三子样旋转矢量算法与传统扩展形式频率级数/显示频率三子样圆锥算法相比误差降低了2个数量级。

杂填土地基中螺杆桩竖向承载特性研究

为了研究杂填土地基中螺杆桩竖向承载特性,基于极限平衡理论分析了桩-土咬合机理,结合桩-土之间的相互作用得到螺纹段等效侧阻力增大系数,在此基础上建立了单桩竖向承载力计算公式,并对杂填土地基中螺杆桩单桩进行缩尺模型试验。结果表明,螺杆桩在竖向荷载作用下,荷载-沉降曲线经历了弹性、弹塑性、塑性破坏3个阶段。根据模型试验所得桩身轴力和桩侧等效侧阻力沿深度的分布规律,总体上螺纹段等效侧阻力高于直杆段。当桩体达到极限承载力时,试验所得等效侧阻力扩大系数与理论分析结果基本一致。

基于爆破荷载等效施加方法的振动波形预测与古建筑安全评估

隧道爆破开挖产生的振动对邻近的古建筑有着不容忽视的安全影响,为研究爆破振动波的传播规律以及预测地面振动效应和分析临近古建筑结构的安全性,以拉卜楞隧道为依托,采用现场实测结合数值模拟分析的方法,预测爆破荷载作用下拉卜楞寺的动力响应。结果表明:(1)随着单响总药量的增加,质点振动速度增大,衰减比也随之增大,说明高频振动衰减快,低频振动衰减慢;(2)通过理论计算将爆破荷载等效施加在弹性边界或隧道开挖轮廓面上,动力模拟结果表明在大于40 m的中远区两者振速变化规律趋于一致,故将荷载施加在开挖轮廓面上是合理的;(3)爆破地震波自由界面处体波经过反射形成沿表面传播的Rayleigh波,结合数值模拟山体内部地震波的传播规律发现,经反射叠加山体内部形成复杂的振动区;(4)当地震波到达拉卜楞寺最近点时,径向振速峰值为0.000672 cm/s,垂向振速峰值为0.000448 cm/s,合成振速峰值为0.000807 cm/s,远小于古建筑安全振动控制标准。

基于STFT-AOK的星箭力学环境等效频谱分析

星箭力学环境的频谱特性研究对于力学试验环境条件设计非常重要。工程上通常基于冲击响应谱变换获得力学环境参数等效频谱,然而该方法受稳态放大系数Q取值的影响较大。为此,文章提出一种基于短时傅里叶变换–自适应优化核函数(STFT-AOK)融合技术的星箭力学环境等效频谱分析方法。研究结果表明:STFT-AOK方法可在AOK准确定位频率成分和瞬态特征时频区域的基础上,结合STFT的准确幅值,构造出频率分辨率高且幅值准确的时频分布,实现力学环境等效频谱的有效获取,适用于各种复杂瞬态星箭力学环境参数的频谱分析。

基于改进等效电路模型的直流微电网大信号稳定性分析

对高阶非线性直流微电网进行简化建模是大信号稳定性分析的有效方法。传统简化模型主要关注LC滤波器和线路阻抗等参数,难以分析换流器控制参数的影响,所建立的判据存在难以准确反映直流微电网稳定域的问题。因此,该文提出直流电压下垂控制换流器的具备完整状态变量集的改进等效电路模型,相比于传统简化模型,能更准确地刻画系统低频响应特性。基于混合势理论推导了直流微电网大信号稳定判据及其稳定域,并结合LaSalle不变集定理得到能量指标,以反映系统稳定性变化趋势。建立的稳定判据可指导控制参数优化,且能拓展到多端直流微电网的大信号稳定性分析。在多场景下仿真验证了所提改进等效电路模型和大信号稳定判据的有效性。

不同因素导致的差异沉降对盾构隧道受力特性影响研究

盾构隧道在下卧地层软硬突变、局部堆载等因素影响下易产生不均匀沉降,可能诱发管片环间错台、螺栓断裂和接缝渗水等病害,危及隧道安全。然而,现有试验研究在隧道模型上多将纵向接头简化处理,难以反映盾构隧道纵向受力变形特性,对于隧道下卧软硬突变地层等工况的模拟也较为缺乏。为此,提出一种可同时模拟抗拉、抗弯刚度的“弹簧+螺栓型”接头,并以此接头制作可满足纵向力学性能相似的隧道模型,对盾构隧道进行下卧软硬突变、局部堆载等工况下的模型试验,进一步探明不同因素导致的差异沉降对盾构隧道的影响机理,并采用数值模拟验证了试验的可行性。研究结果表明:1)较单一地层而言,隧道下卧软硬突变时纵向沉降曲线呈现明显的非线性,其隧道沉降及差异沉降最值显著增大,软土侧隧道沉降较硬土侧更为显著,最大沉降、沉降差均出现在突变区软土侧衬砌处;2)下卧地层突变导致隧道横向收敛变形在纵向上分布不均,使软土侧衬砌收敛变形减小,硬土侧衬砌收敛变形显著增大;3)局部堆载对管片弯矩分布影响较小,对弯矩最值影响较大;4)下卧软土区隧道结构内力分布明显变异,隧道衬砌正弯矩区域显著增大,负弯矩区域略有减小,且弯矩最值提升显著。因此针对软硬突变地层,必要时在硬土侧隧道可采用粘钢法等方法提升衬砌横向刚度,以控制其收敛变形;软土侧隧道建议对管片进行螺栓复紧,并加强接缝防水,以减小下卧地层弱化对隧道结构产生的不利影响。