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Crystal facet-dependent CO_(2) cycloaddition to epoxides over ZnO catalysts

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Frontiers of Chemical Science and Engineering 2024年第5期18卷 49-59页

作者： Yongjian Wei Ying Li Yunfei Xu Yinghui sun Tong Xu haiou Liang Jie Bai Inner Mongolia Key Laboratory of Industrial Catalysis Hohhot 010051China College of Chemical Engineering Inner Mongolia University of TechnologyHohhot 010051China

With regard to green chemistry and sustainable development,the fixation of CO_(2) into epoxides to form cyclic carbonates is an attractive and promising pathway for CO_(2) *** oxides,renowned as promising eco-friendly catalysts for industrial production,are often undervalued in terms of their impact on the CO_(2)addition *** this work,we successfully developed ZnO nanoplates with(002)surfaces and ZnO nanorods with(100)surfaces via morphology-oriented regulation to explore the effect of crystal faces on CO_(2) *** quantitative data obtained from electron paramagnetic resonance spectroscopy indicated that the concentration of oxygen vacancies on the ZnO nanoplate surfaces was more than twice that on the ZnO nanorod *** functional theory calculations suggested that the(002)surfaces have lower adsorption energies for CO_(2) and epichlorohydrin than the(100)*** a result,the yield of cyclochloropropene carbonate on the ZnO nanoplates(64.7%)was much greater than that on the ZnO nanorods(42.3%).Further evaluation of the reused catalysts revealed that the decrease in the oxygen vacancy concentration was the primary factor contributing to the decrease in catalytic *** on these findings,a possible catalytic mechanism for CO_(2) cycloaddition with epichlorohydrin was *** work provides a new idea for the controllable preparation of high-performance ZnO catalysts for the synthesis of cyclic carbonates from CO_(2) and epoxides.

关键词： carbon dioxide cycloaddition zinc oxide crystal face oxygen vacancy

Super-resolution diffractive neural network for alloptical direction of arrival estimation beyond diffraction limits

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Light(Science & Applications) 2024年第8期13卷 1602-1614页

作者： Sheng Gao Hang Chen Yichen Wang Zhengyang Duan haiou Zhang Zhi sun Yuan Shen Xing Lin Department of Electronic Engineering Tsinghua UniversityBeijing 100084China Beijing National Research Center for Information Science and Technology Tsinghua UniversityBeijing 100084China

Wireless sensing of the wave propagation direction from radio sources lays the foundation for communication,radar,navigation,***,the existing signal processing paradigm for the direction of arrival estimation requires the radio frequency electronic circuit to demodulate and sample the multichannel baseband signals followed by a complicated computing process,which places the fundamental limit on its sensing speed and energy ***,we propose the super-resolution diffractive neural networks(S-DNN)to process electromagnetic(EM)waves directly for the DOA estimation at the speed of *** multilayer meta-structures of S-DNN generate super-oscillatory angular responses in local angular regions that can perform the all-optical DOA estimation with angular resolutions beyond the diffraction *** spatial-temporal multiplexing of passive and reconfigurable S-DNNs is utilized to achieve high-resolution DOA estimation over a wide field of *** S-DNN is validated for the DOA estimation of multiple radio sources over 5 GHz frequency bandwidth with estimation latency over two to four orders of magnitude lower than the state-of-the-art commercial devices in *** results achieve the angular resolution over an order of magnitude,experimentally demonstrated with four times,higher than diffraction-limited *** also apply S-DNN’s edge computing capability,assisted by reconfigurable intelligent surfaces,for extremely low-latency integrated sensing and communication with low power *** work is a significant step towards utilizing photonic computing processors to facilitate various wireless sensing and communication tasks with advantages in both computing paradigms and performance over electronic computing.

关键词： beyond optical network

Velocity field in 90° curved duct of cycle section

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Velocity field in 90° curved duct of cycle section

Organic-2D composite material-based RRAM with high reliability for mimicking synaptic behavior

2011 International Conference on Advanced Materials and Computer Science(ICAMCS 2011)

作者： sun Tao ZHANG Yi sun haiou WANG Zhongyi College of Power and Energy Engineering Harbin Engineering University

Flow in curved duct is different from that happens in straight pipeline. Affected by the curved duct curvature, the flow field in a curved duct is uneven. The flow in the curved duct suffers serious loss. Considering the flow field characteristic and engineering applications, the characteristic of the flow field in curved duct without guide plate and the curved duct with different guide plates have been studied based on the numerical results. The velocity distribution and unevenness on the outlet of the curved duct have been analyzed too. Then the best conditions for guide plates installed in curved duct are achieved.

关键词： curved duct guide plate numerical simulation velocity unevenness

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Journal of Materiomics 2024年第2期10卷 440-447页

作者： Tangyou sun Fantao Yu Xiaosheng Tang haiou Li Fabi Zhang Zhimou Xu Qing Liao Zhiqiang Yu Xingpeng Liu Peihua Wangyang Hezhang Li Ying Peng Guangxi Key Laboratory of Precision Navigation Technology and Application Guilin University of Electronic TechnologyGuilin541004China College of Optoelectronic Engineering Chongqing UniversityChongqing400044China School of Optical and Electronic Information Huazhong University of Science and TechnologyWuhan430074China School of Electrical and Information Engineering Guangxi University of Science and TechnologyLiuzhou545006China Department of Precision Instrument Tsinghua UniversityBeijing100084China

The field of artificial intelligence and neural computing has been rapidly expanding due to the imple-mentation of resistive random-access memory(RRAM)based artificial ***,the low flexibility of conventional RRAM materials hinders their ability to mimic synaptic behavior *** overcome such limitation,organic-2D composites with high mechanical properties are proposed as the active layer of ***,we enhance the reliability of the device by ZrO_(2)insertion layer,resulting in stable synaptic *** Ag/PVA:h-BN/ZrO_(2)/ITO devices show stable bipolar resistive switching behavior with an ON/OFF ratio of over 5×10^(2),a~2400 cycles endurance and a long retention time(>6×10^(3)s),which are essential for the development of high-performance *** also study the possible synaptic mechanism and dynamic plasticity of the memory device,observing the transition from short-term potentiation(STP)to long-term potentiation(LTP)under the effect of continuous voltage ***,the device exhibits both long-term depression(LTD)and paired-pulse facili-tation(PPF)properties,which have significant implications for the design of organic-2D composite material RRAMs that aim to mimic biological synapses,representing promising avenues for the devel-opment of advanced neuromorphic computing systems.

关键词： Resistive random-access memory Synaptic mimicking Organic-2D composite material Neuromorphic computing

Downstream Competition and Upstream Innovation:Theory and Evidence from China

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China Finance and Economic Review 2024年第1期13卷 67-87页

作者： Jing Dai Guanchun Liu Ziqi Ye haiou Mao Yongwei Ye School of Finance Hubei University of Economics Lingnan College Sun Yatsen University School of Business Administration Zhongnan University of Economics and Law College of Economics and Management Huazhong Agricultural University School of Public Economics and Management Shanghai University of Finance and Economics

Competition is the catalyst of corporate innovation,which is the foundation of a country's core *** the view of vertical industrial chain,this paper examines how downstream competition affects upstream firms'innovation *** innovation helps reduce the production cost of each product,increasing demand of intermediate products caused by downstream competition enhances the marginal revenue of upstream firms'innovation,thus leading to an innovation incentive *** identify causality,we utilize China's WTO accession,a quasinatural experiment,to calculate downstream competition combined with import tariff reduction and input-output table,and then run a difference-in-difference *** the data of Annual Survey of Industrial Firms and State Intellectual Property Office,our results find that downstream competition has a significantly positive impact on upstream firms'innovation,and this effect is more pronounced in firms with less industry competition,greater initial innovation capacity and weaker financial ***,the number of firms,the degree of industry competition and the scale of intermediate products in the downstream sector increase,confirming the market size *** sum,our findings document that downstream competition can motivate upstream firms to innovate through vertical industrial chain,providing some useful insights for China to build a fair market competition environment and promote innovation-driven growth regime.

关键词： downstream competition upstream firms'innovation vertical industrial chain market size effect

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侧向轧制变胞机构的动力学仿真与优化设计

华中科技大学学报（自然科学版） 2024年第6期52卷 56-62页

作者：孙乐乐张海鸥华中科技大学机械科学与工程学院湖北武汉430074

为了解决电弧增材制造存在变形及微观组织形态和力学性能较差的问题,采用轧制使材料的力学性能得到极大改善.为了合理设计轧制机构,针对一种侧向轧制变胞机构进行动力学分析和优化设计,分别分析了杆件尺寸、主动件速度、弹簧刚度在变胞... 详细信息

为了解决电弧增材制造存在变形及微观组织形态和力学性能较差的问题,采用轧制使材料的力学性能得到极大改善.为了合理设计轧制机构,针对一种侧向轧制变胞机构进行动力学分析和优化设计,分别分析了杆件尺寸、主动件速度、弹簧刚度在变胞机构运动过程中对变胞机构的影响.首先,分析了侧向轧制变胞机构的原理,得到了机构的基本结构;然后,选取合适的设计变量初始值与边界值,确定目标函数及约束条件;最后,在机械系统动力学自动分析(ADAMS)软件中建立机构的虚拟样机模型,在一定的侧向轧制力下,以主动件的驱动力最小为优化目标进行仿真求解,得到驱动力的最优解和相应设计变量的最优值.结果表明:最小驱动力较优化前减小了15.48%,主动件速度、杆件尺寸、弹簧刚度对变胞机构的影响程度是依次减弱的.

关键词：变胞机构电弧增材制造优化设计动态仿真机械系统动力学自动分析(ADAMS)

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粗糙度对边界层流动及压气机气动性能的影响

哈尔滨工程大学学报 2017年第4期38卷 554-560页

作者：孙海鸥叶楠王松王萌王忠义哈尔滨工程大学动力与能源工程学院黑龙江哈尔滨150001

为了研究叶片表面粗糙度对边界层流动及压气机气动性能的影响,本文以T3系列平板转捩实验为对象,通过构建Gauss型粗糙表面来验证等效砂粒模型计算方法的适用性,并采用商业软件ANSYS CFX对NASA Stage35型压气机进行了表面粗糙度的数值模... 详细信息

为了研究叶片表面粗糙度对边界层流动及压气机气动性能的影响,本文以T3系列平板转捩实验为对象,通过构建Gauss型粗糙表面来验证等效砂粒模型计算方法的适用性,并采用商业软件ANSYS CFX对NASA Stage35型压气机进行了表面粗糙度的数值模拟研究。研究结果表明:采用等效砂粒模型进行表面粗糙度的数值研究能够满足工程要求;当动叶表面粗糙度ks由1μm增大至100μm时,压气机峰值效率减小3.5%,对应工况点的压比减小0.8%,总温比升高0.4%。同时,粗糙度增加后的压气机最大压比与光滑情况下相比减小4.5%;计算得到了总损失系数ω和效率损失系数ζ与叶片表面粗糙度的关系,具有一定的工程价值。

关键词：数值模拟轴流压气机表面粗糙度边界层流动等效沙粒模型工作效率压气机

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轴流压气机气固两相流及磨损特性数值模拟

哈尔滨工程大学学报 2018年第2期39卷 310-316页

作者：孙海鸥王萌王忠义裴小萌哈尔滨工程大学动力与能源工程学院黑龙江哈尔滨150001 中航商用航空发动机有限责任公司上海200241

为了研究固体颗粒入射至压气机后导致其性能衰退作用机理,本文采用商业软件ANSYS CFX中的多相流求解技术对某型四级轴流式压气机进行了气固两相流和磨损特性的数值模拟研究。研究结果表明:固体颗粒对压气机叶片的磨损主要集中在前面级... 详细信息

为了研究固体颗粒入射至压气机后导致其性能衰退作用机理,本文采用商业软件ANSYS CFX中的多相流求解技术对某型四级轴流式压气机进行了气固两相流和磨损特性的数值模拟研究。研究结果表明:固体颗粒对压气机叶片的磨损主要集中在前面级的动叶和各排叶片的50%叶高以上,并且磨损量随叶高位置上移而增大;对每个叶片来说,对压力面的磨损程度要大于对吸力面;在沿轴向方向上,磨损主要集中在叶片的前缘和尾缘处。该研究成果具有一定的工程价值和参考价值。

关键词：数值模拟轴流压气机固体颗粒两相流磨损性能衰退磨损率浓度作用机理

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积垢条件下压气机性能衰退数值模拟

哈尔滨工程大学学报 2018年第11期39卷 1773-1778页

作者：孙海鸥王立松王忠义万雷哈尔滨工程大学动力与能源工程学院黑龙江哈尔滨150001

针对轴流压气机在实际工作中遇到的叶片表面磨损、积垢问题,本文以NASA Stage 35单级轴流压气机模型为研究对象,建立了数值计算模型,以压气机的静叶部分为主要研究对象,使用更改静叶叶片表面粗糙度值和不均匀地更改静叶叶型厚度两种不... 详细信息

针对轴流压气机在实际工作中遇到的叶片表面磨损、积垢问题,本文以NASA Stage 35单级轴流压气机模型为研究对象,建立了数值计算模型,以压气机的静叶部分为主要研究对象,使用更改静叶叶片表面粗糙度值和不均匀地更改静叶叶型厚度两种不同方法模拟压气机表面积垢情况,得到压气机效率、压比等性能的衰退情况与不同模拟方法的关系,以及压气机不同程度积垢下的流场变化情况。计算结果表明:更改叶片表面粗糙度对压气机的效率性能影响要大于对压比的影响,叶型厚度的变化会明显影响压气机的稳定工作范围。研究结果可为确定压气机清洗周期和运行寿命预估提供借鉴。

关键词：压气机积垢粗糙度静叶叶片性能参数内部流场