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Mass Transfer-Promoted Fe2+/Fe3+ Circulation Steered by 3D Flow-Through Co-Catalyst System Toward Sustainable

Weiyang Lv,Hao Li,Jinhui Wang,Lixin Wang,Zenglong Wu,Yuge Wang,Wenkai Song,Wenkai Cheng,Yuyuan Yao,

《工程（英文）》 doi: 10.1016/j.eng.2023.06.010

摘要： Realizing fast and continuous generation of reactive oxygen species (ROSs) via iron-based advanced oxidation processes (AOPs) is significant in the environmental and biological fields. However, current AOPs assisted by co-catalysts still suffer from the poor mass/electron transfer and non-durable promotion effect, giving rise to the sluggish Fe2+/Fe3+ cycle and low dynamic concentration of Fe2+ for ROS production. Herein, we present a three-dimensional (3D) macroscale co-catalyst functionalized with MoS2 to achieve ultra-efficient Fe2+ regeneration (equilibrium Fe2+ ratio of 82.4%) and remarkable stability (more than 20 cycles) via a circulating flow-through process. Unlike the conventional batch-type reactor, experiments and computational fluid dynamics simulations demonstrate that the optimal utilization of the 3D active area under the flow-through mode, initiated by the convection-enhanced mass/charge transfer for Fe2+ reduction and then strengthened by MoS2-induced flow rotation for sufficient reactant mixing, is crucial for oxidant activation and subsequent ROS generation. Strikingly, the flow-through co-catalytic system with superwetting capabilities can even tackle the intricate oily wastewater stabilized by different surfactants without the loss of pollutant degradation efficiency. Our findings highlight an innovative co-catalyst system design to expand the applicability of AOPs based technology, especially in large-scale complex wastewater treatment.

关键词： Advanced oxidation processes     3D co-catalyst     Flow-through mode     Enhanced mass transfer     Complex wastewater treatment    

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Electroreduction of hexavalent chromium using a porous titanium flow-through electrode and intelligent

《环境科学与工程前沿（英文）》 2023年 第17卷 第8期 doi: 10.1007/s11783-023-1697-x

摘要：

● Titanium-based flow-through electrode achieved high Cr(VI) reduction efficiency.

关键词： Flow-through electrode     Hexavalent chromium     Heavy metals     Neural network     Artificial intelligence    

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Kinetic studies of xylan hydrolysis of corn stover in a dilute acid cycle spray flow-through reactor

Hongman ZHANG, Qiang JIN, Rui XU, Lishi YAN, Zengxiang LIN

《化学科学与工程前沿（英文）》 2011年 第5卷 第2期   页码 252-257 doi: 10.1007/s11705-010-1010-y

摘要： Xylan of corn stover was pretreated with 1%, 2% and 3% (w/w) sulfuric acid at relatively low temperatures (90°C, 95°C and 100°C) in a dilute acid cycle spray flow-through reactor (DCF). The hydrolysis of xylan to its monomeric xylose was modeled by a series of first-order reactions. Both biphasic and Saeman hydrolysis models were applied to fit the experimental data. The results confirmed that the kinetic data of xylan hydrolysis fitted a first-order irreversible reaction model and the experimental data. The reaction rates of xylose monomer formation and degradation were sensitive to catalyst concentration and temperature. Higher catalyst concentration and lower reaction temperature result in high xylose yield. The activation energy for xylose formation and degradation were determined to be 112.9 and 101.0 kJ·mol , respectively. Over 90% theoretical xylose obtained from corn stover can be used to produce ethanol, xylitol and fumaric acid by fermentation.

关键词： corn stover     xylan hydrolysis     biphasic model     Saeman model     cycle spray     kinetics    

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通过一个等价雷诺数揭示层流到湍流的转捩区域 Article

陈晓东

《工程（英文）》 2019年 第5卷 第3期   页码 576-579 doi: 10.1016/j.eng.2018.09.013

摘要：

Flow transition from laminar to turbulent mode (and vice versa)—that is, the initiation of turbulence—is one of the most important research subjects in the history of engineering. Even for pipe flow, predicting the onset of turbulence requires sophisticated instrumentation and/or direct numerical simulation, based on observing the instantaneous flow structure formation and evolution. In this work, a local Reynolds number equivalence γ (ratio of local inertia effect to viscous effect) is seen to conform to the Universal Law of the Wall, where γ = 1 represents a quantitative balance between the abovementioned two effects. This coincides with the wall layer thickness (y+ = 1, where y+ is the dimensionless distance from the wall surface defined in the Universal Law of the Wall). It is found that the characteristic of how the local derivative of γ against the local velocity changes with increasing velocity determines the onset of turbulence. For pipe flow, γ ≈ 25, and for plate flow, γ ≈ 151.5. These findings suggest that a certain combination of γ and velocity (nonlinearity) can qualify the source of turbulence (i.e., generate turbulent energy). Similarly, a re-evaluation of the previous findings reveals that only the geometrically narrow domain can act locally as the source of turbulence, with the rest of the flow field largely being left for transporting and dissipating. This understanding will have an impact on the future large-scale modeling of turbulence.

关键词： 局部等价雷诺数     转捩     壁面律     管流     平板流动     建模    

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Aerobic granular sludge formation based on substrate availability: Effects of flow pattern and fermentation

Quan Yuan, Hui Gong, Hao Xi, Kaijun Wang

《环境科学与工程前沿（英文）》 2020年 第14卷 第3期 doi: 10.1007/s11783-020-1226-0

摘要： Penetration depth and substrate characters affect AGS formation and performance. The relationship between substrate gradient and particle size affects AGS stability. The fermentation process is proposed as a pretreatment to improve AGS stability. The influences of flow patterns (mixed-flow and plug-flow) and fermentation pretreatment on aerobic granular sludge (AGS) formation with various substrate availability levels were investigated by running four identical laboratory-scale sequencing batch reactors (R1–R4), comparing two anaerobic feeding strategies and three kinds of substrates. R1 achieved faster granulation with a fast influent fill step followed by a modified anaerobic mixed-flow phase, but the AGS showed poorer stability with a cracked structure and a high suspended solids concentration in the effluent. The anaerobic plug-flow feeding mode (with influent fed slowly from the bottom) in R2 provided deeper penetration depth for the substance to reach the core of AGS and accordingly strengthen AGS stability. An acidogenic up-flow sludge bed reactor was introduced as a pretreatment to improve the AGS performance by enhancing glucose pre-fermentation (R4). AGS fed with mixed volatile fatty acids (VFA) after glucose fermentation showed similar performance compared with the reactor fed with acetate in the aspects of stability, structure, size distribution and nitrogen removal efficiency, and 74% similarity in the microbial community. For actual wastewater with low VFA concentrations, fermentation treatment was suggested as a promising pretreatment for stable AGS granulation and operation.

关键词： Anaerobic plug-flow feeding mode     Anaerobic mixed-flow mode     Fermentation pretreatment     Substrate gradient     Penetration depth    

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A hybrid fuel cell for water purification and simultaneously electricity generation

《环境科学与工程前沿（英文）》 2023年 第17卷 第1期 doi: 10.1007/s11783-023-1611-6

摘要：

● A novel hybrid fuel cell (F-HFC) was fabricated.

关键词： Flow-through field     Hybrid fuel cell     Polyoxometalates     Water purification     Electricity generation    

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A way to explain the thermal boundary effects on laminar convection through a square duct

Liangbi WANG, Xiaoping GAI, Kun HUANG, Yongheng ZHANG, Xiang YANG, Xiang WU

《能源前沿（英文）》 2010年 第4卷 第4期   页码 496-506 doi: 10.1007/s11708-010-0020-2

摘要： A way using the reformulation of the energy conservation equation in terms of heat flux to explain the thermal boundary effects on laminar convective heat transfer through a square duct is presented. For a laminar convection through a square duct, it explains that on the wall surface, the velocity is zero, but convection occurs for uniform wall heat flux (UWHF) boundary in the developing region due to the velocity gradient term; for uniform wall temperature (UWT) boundary, only diffusion process occurs on the wall surface because both velocity and velocity gradient do not contribute to convection; for UWHF, the largest term of the gradient of velocity components (the main flow velocity) on the wall surface takes a role in the convection of the heat flux normal to the wall surface, and this role exists in the fully developed region. Therefore, a stronger convection process occurs for UWHF than for UWT on the wall surface. The thermal boundary effects on the laminar convection inside the flow are also detailed.

关键词： convective transport     heat transfer     mass transfer     laminar flow     thermal boundary effects    

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渠网恒定流及非恒定流数学模型的研究及应用

张明亮,沈永明

《中国工程科学》 2007年 第9卷 第8期   页码 92-96

摘要：

从求解一维圣维南方程组的Preissmann 4点隐式差分格式出发, 建立了一维河网及渠网数学模型，并对计算中所涉及的一些关键技术问题进行了较为详细的阐述。利用模型对树状渠网的恒定流及复杂的环状渠网和河网的非恒定流对模型进行验证。验证结果表明，水位和流量过程计算值与Islam的计算值吻合较好，各渠道的流量分配计算结果精度也较高，为河网及渠网的水量调度提供了一个较为简便实用的工具，为建立渠网及河网的综合水质生态数学模型打下基础。

关键词： Preissmann格式     渠网及河网     流量分配     水质模型    

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Anefficient quadrature demodulator for medical ultrasound imaging

Hao ZHOU,Yin-fei ZHENG

《信息与电子工程前沿（英文）》 2015年 第16卷 第4期   页码 301-310 doi: 10.1631/FITEE.1400205

摘要： Quadrature demodulation is used in medical ultrasound imaging to derive the envelope and instantaneous phase of the received radio-frequency (RF) signal. In quadrature demodulation, RF signal is multiplied with the sine and cosine wave reference signal and then low-pass filtered to produce the base-band complex signal, which has high computational complexity. In this paper, we propose an efficient quadrature demodulation method for B-mode and color flow imaging, in which the RF signal is demodulated by a pair of finite impulse response filters without mixing with the reference signal, to reduce the computational complexity. The proposed method was evaluated with simulation and in vivo experiments. From the simulation results, the proposed quadrature demodulation method produced similar normalized residual sum of squares (NRSS) and velocity profile compared with the conventional quadrature demodulation method. In the in vivo color flow imaging experiments, the time of the demodulation process was 5.66 ms and 3.36 ms, for the conventional method and the proposed method, respectively. These results indicated that the proposed method can maintain the performance of quadrature demodulation while reducing computational complexity.

关键词： B-mode ultrasound imaging     Color flow imaging     Quadrature demodulation     Finite impulse response filter    

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主支式排烟道中主烟道横截面尺寸的确定

黄锐,杨立中,范维澄

《中国工程科学》 2001年 第3卷 第11期   页码 45-48

摘要：

高层住宅主支式排烟道的主烟道中烟气流动可看作是一维定常垂直摩擦管流。通过计算管流流动相与颗粒相的物理参数沿管程分布情况，确定了颗粒相流动情况，进而判断烟气排放情况。这受到排烟系统高度、烟道管径，及材料组成等因素的影响，通过预设排烟系统高度并保证良好排放情况，求得主烟道管径应满足的条件。这使得布设排烟道时可以找到一个较好的横截面尺寸，既满足烟气排放条件，又节约修建材料。

关键词： 多相流     主支式厨房排烟道     计算模型    

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Robust SVM-direct torque control of induction motor based on sliding mode controller and sliding mode

Abdelkarim AMMAR,Amor BOUREK,Abdelhamid BENAKCHA

《能源前沿（英文）》 2020年 第14卷 第4期   页码 836-849 doi: 10.1007/s11708-017-0444-z

摘要： This paper proposes a design of control and estimation strategy for induction motor based on the variable structure approach. It describes a coupling of sliding mode direct torque control (DTC) with sliding mode flux and speed observer. This algorithm uses direct torque control basics and the sliding mode approach. A robust electromagnetic torque and flux controllers are designed to overcome the conventional SVM-DTC drawbacks and to ensure fast response and full reference tracking with desired dynamic behavior and low ripple level. The sliding mode controller is used to generate reference voltages in stationary frame and give them to the controlled motor after modulation by a space vector modulation (SVM) inverter. The second aim of this paper is to design a sliding mode speed/flux observer which can improve the control performances by using a sensorless algorithm to get an accurate estimation, and consequently, increase the reliability of the system and decrease the cost of using sensors. The effectiveness of the whole composed control algorithm is investigated in different robustness tests with simulation using Matlab/Simulink and verified by real time experimental implementation based on dS pace 1104 board.

关键词： induction motor     direct torque control (DTC)     space vector modulation (SVM)     sliding mode control (SMC)     sliding mode observer (SMO)     dS1104    

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设计科学中关于知识的研究——经济发展方式转变中要考虑的重要问题

谢友柏

《中国工程科学》 2013年 第15卷 第4期   页码 14-22

摘要：

本文研究了知识在人类设计一切有目的活动中的行为，分析了设计中知识的流动和在竞争中的完整化即进化，论证了创新和设计的关系以及创新和设计的知识本质。提出了设计是以已有知识为基础、设计是以新知识获取为中心、设计知识具有不完整性、竞争性等基本规律和基本特征，认为要依赖创新推动经济增长方式的转变，知识行为研究应该是设计科学的重要命题。

关键词： 设计     设计科学     知识     知识获取     知识流    

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基于双重分组和密钥计数的并行认证模式

黄玉划,胡爱群,宋宇波

《中国工程科学》 2004年 第6卷 第7期   页码 70-74

摘要：

由于CBC－MAC模式不可并行处理，提出了一种基于双重分组的并行认证模式(PKCB)。PKCB模式同并行认证模式PMAC相比，安全性和速率都有显著提高，PKCB认证模式与CTR（计数器）加密模式结合可构成分组密码算法的一种全工作模式。在此基础上提出了一种基于密钥计数的并行认证模式（KCTR－MAC）。KCTR－MAC模式安全性比PMAC模式高得多，而速率未降低，KCTR－MAC认证模式和CTR加密模式结合也可构成分组密码算法的一种全工作模式（2CTR），2CTR模式的综合性能不亚于标准模式CCM（CTR with CBC－MAC），是一种安全快速的实用模式。

关键词： 认证模式     CBC－MAC模式     PMAC模式     CTR模式     CCM模式    

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Numerical study of internal flow field and flow passage improvement of an inlet particle separator

Florian PAOLI, Tong WANG

《能源前沿（英文）》 2011年 第5卷 第4期   页码 386-397 doi: 10.1007/s11708-011-0156-8

摘要： By performing gas flow field numerical simulations for several inlet Reynolds numbers (from 2 × 10 to 9 × 10 ) and byflow ratios (from 10% to 20%), the present study has proposed to improve the flow passage of an inlet particle separator. An adjacent objective of the study is to lower pressure losses of the inlet particle separator (IPS). No particle has been included in the gas flow for a -epsilon turbulence model. The velocity distribution in different sections and the pressure coefficient along the duct have been analyzed, which indicates that there exist important low-velocity regions and vortices in the separation area. Therefore, the profile of streamlines along the original passage has been considered. This profile illustrated a vacuum region in the same area. All investigations suggest that the separation area is the most critical one for fulfilling the objective on pressure losses limitation. Then the flow passage improvement method has focused on the separation area. An improved shape has been designed in order to suit smoothly to the streamlines in this region. Similar numerical studies as those for the original shape have been conducted on this improved shape, confirming some considerable enhancements compared with the original shape. The significant vortices which appear in the original shape reduce in amount and size. Besides, pressure losses are greatly decreased in both outlets (up to 30% for high Reynolds number) and the flow is uniform at the main outlet. Subsequent engineering surveys could rely on expressions obtained for in both outlets which extend the pressure losses for a wide range of inlet Reynolds numbers. As a result, the numerical calculations demonstrate that the flow passage improvement method applied in this study has succeeded in designing a shape which enhances the flow behavior.

关键词： streamlines     pressure losses     flow passage improvement     inlet particle separator (IPS)    

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Probabilistic stability of uncertain composite plates and stochastic irregularity in their buckling mode

《结构与土木工程前沿（英文）》   页码 179-190 doi: 10.1007/s11709-022-0888-z

摘要： In this study, the mechanical properties of the composite plate were considered Gaussian random fields and their effects on the buckling load and corresponding mode shapes were studied by developing a semi-analytical non-intrusive approach. The random fields were decomposed by the Karhunen−Loève method. The strains were defined based on the assumptions of the first-order and higher-order shear-deformation theories. Stochastic equations of motion were extracted using Euler–Lagrange equations. The probabilistic response space was obtained by employing the non-intrusive polynomial chaos method. Finally, the effect of spatially varying stochastic properties on the critical load of the plate and the irregularity of buckling mode shapes and their sequences were studied for the first time. Our findings showed that different shear deformation plate theories could significantly influence the reliability of thicker plates under compressive loading. It is suggested that a linear relationship exists between the mechanical properties’ variation coefficient and critical loads’ variation coefficient. Also, in modeling the plate properties as random fields, a significant stochastic irregularity is obtained in buckling mode shapes, which is crucial in practical applications.

关键词： uncertain composite plate     stochastic assume mode method     Karhunen−Loève theorem     polynomial chaos approach     plate buckling     irregularity in buckling mode shapes    

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标题 作者 时间 类型 操作

Mass Transfer-Promoted Fe2+/Fe3+ Circulation Steered by 3D Flow-Through Co-Catalyst System Toward Sustainable

Weiyang Lv,Hao Li,Jinhui Wang,Lixin Wang,Zenglong Wu,Yuge Wang,Wenkai Song,Wenkai Cheng,Yuyuan Yao,

期刊论文

Electroreduction of hexavalent chromium using a porous titanium flow-through electrode and intelligent

期刊论文

Kinetic studies of xylan hydrolysis of corn stover in a dilute acid cycle spray flow-through reactor

Hongman ZHANG, Qiang JIN, Rui XU, Lishi YAN, Zengxiang LIN

期刊论文

通过一个等价雷诺数揭示层流到湍流的转捩区域

陈晓东

期刊论文

Aerobic granular sludge formation based on substrate availability: Effects of flow pattern and fermentation

Quan Yuan, Hui Gong, Hao Xi, Kaijun Wang

期刊论文

A hybrid fuel cell for water purification and simultaneously electricity generation

期刊论文

A way to explain the thermal boundary effects on laminar convection through a square duct

Liangbi WANG, Xiaoping GAI, Kun HUANG, Yongheng ZHANG, Xiang YANG, Xiang WU

期刊论文

渠网恒定流及非恒定流数学模型的研究及应用

张明亮,沈永明

期刊论文

Anefficient quadrature demodulator for medical ultrasound imaging

Hao ZHOU,Yin-fei ZHENG

期刊论文

主支式排烟道中主烟道横截面尺寸的确定

黄锐,杨立中,范维澄

期刊论文

Robust SVM-direct torque control of induction motor based on sliding mode controller and sliding mode

Abdelkarim AMMAR,Amor BOUREK,Abdelhamid BENAKCHA

期刊论文

设计科学中关于知识的研究——经济发展方式转变中要考虑的重要问题

谢友柏

期刊论文

基于双重分组和密钥计数的并行认证模式

黄玉划,胡爱群,宋宇波

期刊论文

Numerical study of internal flow field and flow passage improvement of an inlet particle separator

Florian PAOLI, Tong WANG

期刊论文

Probabilistic stability of uncertain composite plates and stochastic irregularity in their buckling mode

期刊论文