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Z源逆变器在异步电动机中的应用

朱红,祝龙记,夏若飞

《中国工程科学》 2014年第16卷第3期页码 86-91

摘要：本文采用IFOC技术来控制异步电机的速度大小，并使用Z源逆变器，即在逆变器主电路前加上一对阻抗（LC）网络，通过控制直通占空比，可以实现升/降压功能、提高异步电机的效率。

关键词： IFOC 异步电机 Z源逆变器

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直接驱动Z箍缩的FLTD型脉冲功率源的发展

孙凤举,邱爱慈,曾正中,曾江涛,丛培天

《中国工程科学》 2009年第11卷第11期页码 56-63

摘要：

介绍了快直线型变压器（FLTD）脉冲源的技术特点；概述了美国圣地亚国家实验室与俄罗斯强流电子学研究所合作研制的FLTD－Z模块的新进展，基于FLTD拟重复频率运行的针对聚变能源（IFE）应用的原理性样机Z－POP装置，以及下一代惯性约束核聚变（ICF）和IFE用的指标为6 MV,60 MA/90 MA和100 ns FLTD型直接驱动脉冲源的概念设想；初步分析了FLTD直接驱动源需要研究的关键技术。

关键词：快Z箍缩直接驱动 FLTD型脉冲加速器高功率脉冲加速器概念设计

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Exergy analysis of R1234ze(Z) as high temperature heat pump working fluid with multi-stage compression

WANG, R.Z. WANG

《能源前沿（英文）》 2017年第11卷第4期页码 493-502 doi: 10.1007/s11708-017-0510-6

摘要： In this paper, the simulation approach and exergy analysis of multi-stage compression high temperature heat pump (HTHP) systems with R1234ze(Z) working fluid are conducted. Both the single-stage and multi-stage compression cycles are analyzed to compare the system performance with 120°C pressurized hot water supply based upon waste heat recovery. The exergy destruction ratios of each component for different stage compression systems are compared. The results show that the exergy loss ratios of the compressor are bigger than that of the evaporator and the condenser for the single-stage compression system. The multi-stage compression system has better energy and exergy efficiencies with the increase of compression stage number. Compared with the single-stage compression system, the coefficient of performance (COP) improvements of the two-stage and three-stage compression system are 9.1% and 14.6%, respectively. When the waste heat source temperature is 60°C, the exergy efficiencies increase about 6.9% and 11.8% for the two-stage and three-stage compression system respectively.

关键词： multi-stage compression high temperature heat pump heat recovery exergy destruction R1234ze(Z) working fluid

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基于Z数的TODIM与TOPSIS方法 None

Renato A. KROHLING, André G. C. PACHECO, Guilherme A. dos SANTOS

《信息与电子工程前沿（英文）》 2019年第20卷第2期页码 283-291 doi: 10.1631/FITEE.1700434

摘要：提出一种针对多标准决策问题处理Z数的方法。使用模糊数A和B的有序对Z=(A, B)定义Z数，其中A是兴趣变量的语言值，B是A的概率测度语言值。将Z数转化为模糊数，Z-TODIM和Z-TOPSIS分别是模糊TODIM和模糊TOPSIS的直接扩展。将提出的方法应用于两个案例并与使用精确数的标准方法比较，结果证明其可行。

关键词：多标准决策；TODIM；TOPSIS；模糊数；Z数

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快Z-箍缩——有前景的聚变能源新途径

彭先觉,华欣生

《中国工程科学》 2008年第10卷第1期页码 47-53

摘要：

简要介绍了快Z-箍缩的基本概念；综述了快Z-箍缩等离子体研究及其作为高能密度物理与惯性约束聚变（ICF），尤其作为低成本聚变能源研究的最新进展；探讨了快Z-箍缩驱动ICF作为聚变能源可能遇到的技术问题及应用前景。

关键词：快Z-箍缩内爆高能密度物理惯性约束聚变聚变能源

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Z干扰信道下非正则信号的最佳设计策略 Article

Dan LI, Shan WANG, Fang-lin GU

《信息与电子工程前沿（英文）》 2017年第18卷第11期页码 1900-1912 doi: 10.1631/FITEE.1700030

摘要：本文提出一种用于在干扰被视为加性高斯噪声的假设下在Z干扰信道（z-interference channel, Z-IC）上实现非正则高斯信号（IGS）的Pareto边界（可实现速率区域的边界）。

关键词： Z干扰信道；非正则信号；和速率；帕累托边界；协方差；伪协方差

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Fire hazard in transportation infrastructure: Review, assessment, and mitigation strategies

Z. NASER

《结构与土木工程前沿（英文）》 2021年第15卷第1期页码 46-60 doi: 10.1007/s11709-020-0676-6

摘要： This paper reviews the fire problem in critical transportation infrastructures such as bridges and tunnels. The magnitude of the fire problem is illustrated, and the recent increase in fire problems in bridges and tunnels is highlighted. Recent research undertaken to address fire problems in transportation structures is reviewed, as well as critical factors governing the performance of those structures. Furthermore, key strategies recommended for mitigating fire hazards in bridges and tunnels are presented, and their applicability to practical situations is demonstrated through a practical case study. Furthermore, research needs and emerging trends for enhancing the “state-of-the-art” in this area are discussed.

关键词： fire hazard bridges tunnels fire resistance mitigation strategies transportation infrastructure

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硅微z轴谐振陀螺仪负电刚度效应分析及实验验证

夏敦柱,周百令,王寿荣

《中国工程科学》 2007年第9卷第8期页码 66-68

摘要：

介绍了在开环工作状态下硅微z轴谐振陀螺仪由于加工工艺缺陷所导致的误差机理。通过对硅微z轴陀螺仪敏感模态的反馈力与谐振频率的关系分析，间接得出了在敏感方向上电负刚度与力矩器所施电压的内在联系，并在实验上进一步验证电刚度效应。这将为下一步闭环控制方案的设计奠定重要基础。

关键词：硅微z轴陀螺仪负电刚度力矩反馈器微机电系统

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Z-scheme CdS/WO on a carbon cloth enabling effective hydrogen evolution

《能源前沿（英文）》 2021年第15卷第3期页码 678-686 doi: 10.1007/s11708-021-0768-6

摘要： Photocatalytic water splitting for hydrogen (H₂) generation is a potential strategy to solve the problem of energy crisis and environmental deterioration. However, powder-like photocatalysts are difficult to recycle, and the agglomeration of particles would affect the photocatalytic activity. Herein, a direct Z-scheme CdS/WO₃ composite photocatalyst was fabricated based on carbon cloth through a two-step process. With the support of carbon cloth, photocatalysts tend to grow uniformly for further applications. The experimental results showed that the H₂ yield of adding one piece of CdS/WO₃ composite material was 17.28 μmol/h, which was 5.5 times as compared to that of pure CdS-loaded carbon cloth material. A cycle experiment was conducted to verify the stability of the as-prepared material and the result demonstrated that the H₂ generation performance of CdS/WO₃ decreased slightly after 3 cycles. This work provides new ideas for the development of recyclable photocatalysts and has a positive significance for practical applications.

关键词： photocatalysis CdS/WO₃ carbon cloth Z-scheme hydrogen evolution

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ZnFe₂O₄/BiVO₄ Z-scheme heterojunction for efficient visible-light photocatalytic

《化学科学与工程前沿（英文）》 2023年第17卷第11期页码 1728-1740 doi: 10.1007/s11705-023-2322-z

摘要： A novel Z-scheme ZnFe₂O₄/BiVO₄ heterojunction photocatalyst was successfully synthesized using a convenient solvothermal method and applied in the visible light photocatalytic degradation of ciprofloxacin, which is a typical antibiotic contaminant in wastewater. The heterostructure of as-synthesized catalysts was confirmed using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy characterizations. Compared with the single-phase counterparts, ZnFe₂O₄/BiVO₄ demonstrated considerably enhanced photogenerated charge separation efficiencies because of the Z-scheme transfer mechanism of electrons between the composite photocatalysts. Consequently, the 30% ZnFe₂O₄/BiVO₄ catalyst afforded a degradation rate of up to 97% of 20 mg/L ciprofloxacin under 30 min of visible light irradiation with a total organic carbon removal rate of 50%, which is an excellent activity compared with ever reported BiVO₄-based catalysts. In addition, the liquid chromatography-mass spectrometry and quantitative structure-activity relationships model analyses demonstrated that the toxicity of the intermediates was lower than that of the parent ciprofloxacin. Moreover, the as-synthesized ZnFe₂O₄/BiVO₄ heterojunctions were quite stable and could be reused at least four times. This study thus provides a promising Z-scheme heterojunction photocatalyst for the efficient removal and detoxication of antibiotic pollutants from wastewater.

关键词： ZnFe₂O₄/BiVO₄ Z-scheme heterojunction photocatalytic degradation ciprofloxacin

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Upgrading of derived pyrolysis vapors for the production of biofuels from corncobs

Liaoyuan Mao, Yanxin Li, Z. Conrad Zhang

《化学科学与工程前沿（英文）》 2018年第12卷第1期页码 50-58 doi: 10.1007/s11705-017-1685-4

摘要： A bubbling fluidized bed pyrolyzer was integrated with an honeycomb as a catalytic upgrading zone for the conversion of biomass to liquid fuels. In the upgrading zone, zeolite coated ceramic honeycomb (ZCCH) catalysts consisting of ZSM-5 (Si/Al=25) were stacked and N or recycled non-condensable gas was used as a carrier gas. Ground corncob particles were fast pyrolyzed in the bubbling bed using fine sand particles as a heat carrier and the resulting pyrolysis vapors were passed on-line over the catalytic upgrading zone. The influence of carrier gas, temperature, and weight hourly space velocity (WHSV) of catalyst on the oil product properties, distribution and mass balance were studied. Using ZCCH effectively increased the hydrocarbon yield and the heating value of the dry oil, especially in the presence of the recycled noncondensable gas. Even a low usage of zeolite catalyst at WSHV of 180 h was effective in upgrading the pyrolysis oil and other light olefins. The highest hydrocarbon (≥C2) and liquid aromatics yields reached to 14.23 and 4.17 wt-%, respectively. The undesirable products including light oxygenates, furans dramatically decreased in the presence of the ZCCH catalyst.

关键词： corncob monolith upgrading pyrolysis

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低调制度下二极管箝位型多电平逆变器新型PWM控制方法

辛想,张庆范,胡顺全,李瑞来

《中国工程科学》 2007年第9卷第10期页码 91-96

摘要：

二极管箝位型多电平逆变器作为一种应用于高压大功率变换场合的变换器，其PWM控制技术是研究的核心内容之一。仿真结果表明，这种方法可以提高二极管箝位型逆变器在低调制度下的器件利用率，使得逆变器在低调制度下工作于较高频率。

关键词：二极管箝位型逆变器载波PWM 低调制度冗余状态

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Predicting the response of continuous RC deep beams under varying levels of differential settlement

Z. NASER, R. A. HAWILEH

《结构与土木工程前沿（英文）》 2019年第13卷第3期页码 686-700 doi: 10.1007/s11709-018-0506-2

摘要： This paper investigates the effect of differential support settlement on shear strength and behavior of continuous reinforced concrete (RC) deep beams. A total of twenty three-dimensional nonlinear finite element models were developed taking into account various constitutive laws for concrete material in compression (crushing) and tension (cracking), steel plasticity (i.e., yielding and strain hardening), bond-slip at the concrete and steel reinforcement interface as well as unique behavior of spring-like support elements. These models are first validated by comparing numerical predictions in terms of load-deflection response, crack propagation, reaction distribution, and failure mode against that of measured experimental data reported in literature. Once the developed models were successfully validated, a parametric study was designed and performed. This parametric study examined number of critical parameters such as ratio and spacing of the longitudinal and vertical reinforcement, compressive and tensile strength of concrete, as well as degree (stiffness) and location of support stiffness to induce varying levels of differential settlement. This study also aims at presenting a numerical approach using finite element simulation, supplemented with coherent assumptions, such that engineers, practitioners, and researchers can carry out simple, but yet effective and realistic analysis of RC structural members undergoing differential settlements due to variety of load actions.

关键词： concrete continuous beams deep beams finite element modeling support settlement

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Heat transfer of phase change materials (PCMs) in porous materials

C Y ZHAO, D ZHOU, Z G WU

《能源前沿（英文）》 2011年第5卷第2期页码 174-180 doi: 10.1007/s11708-011-0140-3

摘要： In this paper, the feasibility of using metal foams to enhance the heat transfer capability of phase change materials (PCMs) in low- and high-temperature thermal energy storage systems was assessed. Heat transfer in solid/liquid phase change of porous materials (metal foams and expanded graphite) at low and high temperatures was investigated. Organic commercial paraffin wax and inorganic calcium chloride hydrate were employed as the low-temperature materials, whereas sodium nitrate was used as the high-temperature material in the experiment. Heat transfer characteristics of these PCMs embedded with open-cell metal foams were studied. Composites of paraffin and expanded graphite with a graphite mass ratio of 3%, 6%, and 9% were developed. The heat transfer performances of these composites were tested and compared with metal foams. The results indicate that metal foams have better heat transfer performance due to their continuous inter-connected structures than expanded graphite. However, porous materials can suppress the effects of natural convection in liquid zone, particularly for PCMs with low viscosities, thereby leading to different heat transfer performances at different regimes (solid, solid/liquid, and liquid regions). This implies that porous materials do not always enhance heat transfer in every regime.

关键词： heat transfer thermal energy storage phase change materials natural convection porous media

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Evaluation of transmissibility for a class of nonlinear passive vibration isolators

Z. K. PENG, Z. Q. LANG, G. MENG

《机械工程前沿（英文）》 2012年第7卷第4期页码 401-409 doi: 10.1007/s11465-012-0349-9

摘要：

In this study, the concept of Output Frequency Response Functions (OFRFs) is applied to represent the transmissibility of nonlinear isolators in frequency domain. With the OFRFs estimated from numerical simulation responses, an explicit analytical relationship between the transmissibility and the nonlinear characteristic parameters is derived for a wide class of nonlinear isolators that have nonlinear anti-symmetric damping characteristics and a comprehensive pattern about how the nonlinear damping characteristic parameters might affect the force and displacement transmissibility is built for the vibration isolators. The results reveal that it is reasonable to analyze the force and displacement transmissibility of the nonlinear isolators by simply investigating the fundamental harmonic components of the force and displacement outputs of the nonlinear isolators, and the introduction of a nonlinear anti-symmetric damping into vibration isolators can significantly suppress both the force and displacement transmissibility over the resonant frequency region, but has almost no effect on the transmissibility at non-resonant regions. These conclusions are of significant importance in the analysis and design of the nonlinear vibration isolators with nonlinear anti-symmetric damping.

关键词： nonlinear vibration volterra series Output Frequency Response Functions (OFRFs) nonlinear damping vibration isolator