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Effect of adjusted mesoscale drag model on flue gas desulfurization in powder-particle spouted beds

《化学科学与工程前沿（英文）》 2022年第16卷第6期页码 909-920 doi: 10.1007/s11705-021-2100-8

摘要： An energy minimum multiscale model was adjusted to simulate the mesoscale structure of the flue gas desulfurization process in a powder-particle spouted bed and verified experimentally. The obtained results revealed that the spout morphology simulated by the adjusted mesoscale drag model was unstable and discontinuous bubbling spout unlike the stable continuous spout obtained using the Gidaspow model. In addition, more thorough gas radial mixing was achieved using the adjusted mesoscale drag model. The mass fraction of water in the gas mixture at the outlet determined by the heterogeneous drag model was 1.5 times higher than that obtained by the homogeneous drag model during the simulation of water vaporization. For the desulfurization reaction, the experimental desulfurization efficiency was 75.03%, while the desulfurization efficiencies obtained by the Gidaspow and adjusted mesoscale drag models were 47.63% and 75.08%, respectively, indicating much higher accuracy of the latter technique.

关键词： adjusted mesoscale drag model particle image velocimetry water vaporization desulfurization reaction numerical simulation

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Development of an analytical model to estimate the churning losses in high-speed axial piston pumps

《机械工程前沿（英文）》 2022年第17卷第2期 doi: 10.1007/s11465-021-0671-1

摘要： The axial piston pumps in aerospace applications are often characterized by high-speed rotation to achieve great power density. However, their internal rotating parts are fully immersed in the casing oil during operation, leading to considerable churning losses (more than 10% of total power losses) at high rotational speeds. The churning losses deserve much attention at the design stage of high-speed axial piston pumps, but accurate analytical models are not available to estimate the drag torque associated with the churning losses. In this paper, we derive the analytical expressions of the drag torque acting on the key rotating parts immersed in oil, including the cylinder block and the multiple pistons in a circular array. The calculated drag torque agrees well with the experimental data over a wide range of rotational speeds from 1500 to 12000 r/min. The presented analytical model provides practical guidelines for reducing the churning losses in high-speed axial piston pumps or motors.

关键词： axial piston pump rotating parts high rotational speed churning losses drag torque

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Mesoscale fabrication of a complex surface for integral impeller blades

Xibin WANG,Tianfeng ZHOU,Lijing XIE,Li JIAO,Zhibing LIU,Zhiqiang LIANG,Pei YAN

《机械工程前沿（英文）》 2017年第12卷第1期页码 116-131 doi: 10.1007/s11465-017-0426-1

摘要：

Integral impeller is the most important component of a mini-engine. However, the machining of a mesoscale impeller with a complex integral surface is difficult because of its compact size and high accuracy requirement. A mesoscale component is usually manufactured by milling. However, a conventional milling tool cannot meet the machining requirements because of its size and stiffness. For the fabrication of a complex integral impeller, a micro-ball-end mill is designed in accordance with the non-instantaneous-pole envelope principle and manufactured by grinding based on the profile model of the helical groove and the mathematical model of the cutting edge curve. Subsequently, fractal theory is applied to characterize the surface quality of the integral impeller. The fractal theory-based characterization shows that the completed mesoscale integral impeller exhibits a favorable performance in terms of mechanical properties and morphological accuracy.

关键词： mesoscale fabrication micro-milling tool mesoscale milling impeller blade

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Photoreduction adjusted surface oxygen vacancy of BiMoO for boosting photocatalytic redox performance

《化学科学与工程前沿（英文）》 2023年第17卷第12期页码 1937-1948 doi: 10.1007/s11705-023-2353-5

摘要： In this study, Bi₂MoO₆ with adjustable rich oxygen vacancies was prepared by a novel and simple solvothermal-photoreduction method which might be suitable for a large-scale production. The experiment results show that Bi₂MoO₆ with rich oxygen vacancies is an excellent photocatalyst. The photocatalytic ability of BMO-10 is 0.3 and 3.5 times higher than that of the pristine Bi₂MoO₆ for Rhodamine B degradation and Cr(VI) reduction, respectively. The results display that the band energy of the samples with oxygen vacancies was narrowed and the light absorption was broadened. Meanwhile, the efficiency of photogenerated electron-holes was increased and the separation and transfer speed of photogenerated carriers were improved. Therefore, this work provides a convenient and efficient method to prepare potential adjustable oxygen vacancy based photocatalysts to eliminate the pollution of dyes and Cr(VI) in water.

关键词： Bi₂MoO₆ oxygen vacancies photoreduction Cr(VI) RhB

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Development of a hydrodynamic model and the corresponding virtual software for dual-loop circulating

Shanwei Hu, Xinhua Liu

《化学科学与工程前沿（英文）》 2021年第15卷第3期页码 579-590 doi: 10.1007/s11705-020-1953-6

摘要： Dual-loop circulating fluidized bed (CFB) reactors have been widely applied in industry because of their good heat and mass transfer characteristics and continuous handling ability. However, the design of such reactors is notoriously difficult owing to the poor understanding of the underlying mechanisms, meaning it has been heavily based on empiricism and stepwise experiments. Modeling the gas-solid CFB system requires a quantitative description of the multiscale heterogeneity in the sub-reactors and the strong coupling between them. This article proposed a general method for modeling multi-loop CFB systems by utilizing the energy minimization multiscale (EMMS) principle. A full-loop modeling scheme was implemented by using the EMMS model and/or its extension models to compute the hydrodynamic parameters of the sub-reactors, to achieve the mass conservation and pressure balance in each circulation loop. Based on the modularization strategy, corresponding interactive simulation software was further developed to facilitate the flexible creation and fast modeling of a customized multi-loop CFB reactor. This research can be expected to provide quantitative references for the design and scale-up of gas-solid CFB reactors and lay a solid foundation for the realization of virtual process engineering.

关键词： multi-loop circulating fluidized bed mathematical modeling energy minimization multiscale virtual fluidization mesoscale structure

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在推力和阻力作用下飞行器横向振动分析

宋健

《中国工程科学》 2000年第2卷第10期页码 63-72

摘要：

文章重点讨论了推力和空气阻力对火箭横向振动频率和振型的影响，分析了在推力和阻力作用下频率降低的原因，给出了推力对振型频率影响的估计式。发动机喷管与火箭固联时的横向运动方程式及其相应的边界条件是分析工作的基础。文中得到的主要结论适用于主动加速段、被动减速段和推力与阻力平衡时的巡航段。在小推力和小轴向过载的情况下，各种不同的计算方法所得的结果相差不大。在大推力和高过载情况下，不同的近似解与精确解的差别可能是很大的。

关键词：飞行器火箭横向振动推力与阻力振型与频率

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基于大气阻力的立方星编队飞行非线性规划控制算法 Article

Sheng-chao DENG, Tao MENG, Zhong-he JIN

《信息与电子工程前沿（英文）》 2017年第18卷第7期页码 867-881 doi: 10.1631/FITEE.1500493

摘要：立方星由于体积和功率限制，难以配置传统的推进系统以实现编队飞行。而大气阻力是低轨卫星可以用于轨道调整的空间环境动力之一。本文提出一种通过大气阻力实现轨道面内沿迹跟飞编队的综合策略，并将用于浙江大学下一颗皮纳卫星（该卫星是国际QB50项目成员之一）。QB50项目主要任务是90–300 km高度近地大气层探测。在这一轨道高度，大气阻力对卫星姿态和轨道的影响均不能忽略。本文通过空气动力学分析，同时考虑大气阻力对轨道半长轴和偏心率的影响，设计了一种多维非线性约束规划策略，以计算实现编队所需的卫星之间不同的目标面质比和相应的轨道调整保持时间。此外，通过俯仰姿态机动调整目标面质比。该算法策略无需卫星配置任何展开机构。基于ZJUCubeSat的数值仿真验证了这一设计的可行性和优势。

关键词： QB50；ZJUCubeSat；大气阻力；编队飞行

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Phase- and epidemic region-adjusted estimation of the number of coronavirus disease 2019 cases in China

Ruijie Chang, Huwen Wang, Shuxian Zhang, Zezhou Wang, Yinqiao Dong, Lhakpa Tsamlag, Xiaoyue Yu, Chen Xu, Yuelin Yu, Rusi Long, Ning-Ning Liu, Qiao Chu, Ying Wang, Gang Xu, Tian Shen, Suping Wang, Xiaobei Deng, Jinyan Huang, Xinxin Zhang, Hui Wang, Yong Cai

《医学前沿（英文）》 2020年第14卷第2期页码 199-209 doi: 10.1007/s11684-020-0768-7

摘要： The outbreak of the coronavirus disease 2019 was first reported in Wuhan in December 2019 and gradually spread to other areas in China. After implementation of prevention and control measures, the estimation of the epidemic trend is needed. A phase- and region-adjusted SEIR model was applied for modeling and predicting the number of cases in Wuhan, Hubei Province and regions outside Hubei Province in China. The estimated number of infections could reach its peak in late February 2020 in Wuhan and Hubei Province, which is 55 303–84 520 and 83 944–129 312, respectively, while the epidemic peaks in regions outside Hubei Province in China could appear on February 13, 2020 with the estimated 13 035–19 108 cases. According to the estimation, the outbreak would abate in March and April all over China. Current estimation provided evidence for planned work resumption under stringent prevention and control in China to further support the fight against the epidemic. Nevertheless, there is still possibility of the second outbreak brought by the work resumption and population migration, especially from Hubei Province and high intensity cities outside Hubei Province. Strict prevention and control measures still need to be considered in the regions with high intensity of epidemic and densely-populated cities.

关键词： SEIR model COVID-19 estimate China

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动态荷载作用下钢纤维混凝土细观模拟方法及应用综述 Review

张锦华, 吴彰钰, 余红发, 麻海燕, 达波

《工程（英文）》 2022年第16卷第9期页码 220-238 doi: 10.1016/j.eng.2022.01.011

摘要：

近年来钢纤维混凝土（SFRC）因对动态和冲击荷载具有优异力学响应而备受关注。现有的试验结果表明，嵌入混凝土基体中的高强度钢纤维具有很强的桥接效应，可以增强纤维与基体之间的结合力，有助于改善SFRC 开裂后性能和残余强度。为了更好地了解钢纤维在基体中的行为表现，以及进一步掌握SFRC在动态荷载作用下的失效机理，细观模拟方法已被广泛用于模拟SFRC材料和结构件的动态响应。细观模拟方法假设SFRC 由不同的细观组分组成，包括钢纤维、粗骨料、砂浆基体和界面过渡区（ITZ）。本文全面综述了动态荷载下SFRC的最新细观模型和模拟过程，系统对比了不同数值模拟研究中SFRC细观模型的生成方法，包括钢纤维、粗骨料及其之间的ITZ。全面总结了不同细观组分的材料模型及纤维与混凝土基体间的相互作用关系。此外，列举了不同动态荷载（即压缩、拉伸和接触爆炸）作用下SFRC细观模拟应用实例。最后，重点分析了现有SFRC细观模拟方法存在的不足，对于SFRC的未来研究及发展具有重要意义。

关键词：钢纤维混凝土细观尺度建模动态荷载材料模型界面特性

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中尺度机器人群集设计创新：合作式城市传感和测绘场景下的应用 Special Feature on Intelligent Design

Audelia G. DHARMAWAN, Gim Song SOH, Shaohui FOONG, Roland BOUFFANAIS, Kristin L. WOOD

《信息与电子工程前沿（英文）》 2019年第20卷第12期 doi: 10.1631/FITEE.1900384

摘要：由于中尺度机器人具有隐蔽性、便携性等特点，安全与监测领域的中尺度机器人研发越来越受到重视。为实现快速、节能、分布式、自适应、具有鲁棒性和可伸缩的系统，中尺度机器人设计和开发需大量硬件、控制和行为创新。本文从4方面详述其设计和开发过程：（1）嵌入式平台的系谱学；（2）关键系统架构和功能布局；（3）研发和实施中尺度机器人系统的设计原则；（4）为中尺度机器人族群有效集体运作而开发的各种关键算法，及在城市传感和测绘领域的应用。这需要我们对可靠运行的嵌入式硬件需求具有清晰认知，以及在磁感、室内定位、中央模式发生器控制和中尺度器人群体分布式自治方面作出关键创新。虽然在复杂机器人系统设计过程中不可避免采用一些临时方法，但本文主要关注成体系系统的设计过程以及组件设计集成。成体系系统的设计过程为该领域未来系统的开发提供了基础。本文所介绍的设计代表最新发展趋势，可作为其他应用的基准，并推广到其他领域。

关键词：成体系系统设计；中尺度机器人；群集；城市传感

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探索知识体系的逻辑与架构：多层次、多尺度及介尺度复杂性

李静海

《工程（英文）》 2016年第2卷第3期页码 276-285 doi: 10.1016/J.ENG.2016.03.001

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Effect of catalyst layer mesoscopic pore-morphology on cold start process of PEM fuel cells

Ahmed Mohmed DAFALLA, Fangming JIANG

《能源前沿（英文）》 2021年第15卷第2期页码 460-472 doi: 10.1007/s11708-021-0733-4

摘要： Water transport is of paramount importance to the cold start of proton exchange membrane fuel cells (PEMFCs). Analysis of water transport in cathode catalyst layer (CCL) during cold start reveals the distinct characteristics from the normal temperature operation. This work studies the effect of CCL mesoscopic pore-morphology on PEMFC cold start. The CCL mesoscale morphology is characterized by two tortuosity factors of the ionomer network and pore structure, respectively. The simulation results demonstrate that the mesoscale morphology of CCL has a significant influence on the performance of PEMFC cold start. It was found that cold-starting of a cell with a CCL of less tortuous mesoscale morphology can succeed, whereas starting up a cell with a CCL of more tortuous mesoscale morphology may fail. The CCL of less tortuous pore structure reduces the water back diffusion resistance from the CCL to proton exchange membrane (PEM), thus enhancing the water storage in PEM, while reducing the tortuosity in ionomer network of CCL is found to enhance the water transport in and the water removal from CCL. For the sake of better cold start performance, novel preparation methods, which can create catalyst layers of larger size primary pores and less tortuous pore structure and ionomer network, are desirable.

关键词： cold start energy conversion fuel cells mesoscale morphology tortuosity water management

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易凝高粘原油管输技术及其发展

张劲军

《中国工程科学》 2002年第4卷第6期页码 71-76

摘要：

我国所产原油80%以上为凝点较高的含蜡原油和粘稠的重质原油，其节能、安全输送一直是我国油气储运界面临的主要技术难题。简要介绍了这两类原油的流动特性及机理，概括了原油降凝减阻输送技术研究和应用的现状，分析了其发展趋势，提出了进一步研究需重点解决的问题。预计化学降凝剂改性仍将是含蜡原油节能安全输送技术的发展方向，目前需重点攻克大庆原油改性的难关；稠油乳化降粘减阻技术将得到更多的应用，在我国目前应重点针对海上油田的油水混输管道开展研究。现有技术的提升、新技术的涌现，有赖于基础研究的突破、技术路线的大胆创新和相关。

关键词：管道输送石蜡基原油重质原油降凝减阻化学添加剂

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介尺度中的复杂性——人工智能发展中的共性挑战 Perspective

郭力, 邬俊, 李静海

《工程（英文）》 2019年第5卷第5期页码 924-929 doi: 10.1016/j.eng.2019.08.005

摘要：

探索复杂系统背后的物理机制并加以有效利用，是处理各类复杂事物的普适性方法。大数据的兴起与计算能力的提升，加之优化算法的改进，触发了以深度学习为驱动的人工智能变革，并在多个应用领域取得了突破性进展。然而，深度学习难以揭示所解决问题的底层逻辑和物理内涵，进而阻碍了其进一步发展。介科学提出了理解复杂系统时空多尺度结构的原理和方法，已在多个领域见到成效。本文提出“基于介科学的人工智能”研究范式，将介科学原理和方法应用于深度学习模型设计，旨在弥补其模型脱离问题物理原型这一根本性问题，探索人工智能可持续发展的有效途径。

关键词：人工智能，深度学习，介科学，介尺度，复杂系统

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Standard model of knowledge representation

Wensheng YIN

《机械工程前沿（英文）》 2016年第11卷第3期页码 275-288 doi: 10.1007/s11465-016-0372-3

摘要：

Knowledge representation is the core of artificial intelligence research. Knowledge representation methods include predicate logic, semantic network, computer programming language, database, mathematical model, graphics language, natural language, etc. To establish the intrinsic link between various knowledge representation methods, a unified knowledge representation model is necessary. According to ontology, system theory, and control theory, a standard model of knowledge representation that reflects the change of the objective world is proposed. The model is composed of input, processing, and output. This knowledge representation method is not a contradiction to the traditional knowledge representation method. It can express knowledge in terms of multivariate and multidimensional. It can also express process knowledge, and at the same time, it has a strong ability to solve problems. In addition, the standard model of knowledge representation provides a way to solve problems of non-precision and inconsistent knowledge.

关键词： knowledge representation standard model ontology system theory control theory multidimensional representation