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An effective pumping method for increasing atomic utilization in a compact cold atom clock

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Chinese Physics B 2021年第8期30卷 317-321页

作者： xin-chuan ouyang Bo-Wen Yang Jian-Liao Deng Jin-Yin Wan Ling Xiao Hang-Hang Qi Qing-Qing Hu Hua-Dong Cheng Key Laboratory of Quantum Optics and Center of Cold Atom Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Advanced Interdisciplinary Technology Research Center National Innovation Institute of Defense TechnologyBeijing 100010China

We propose a simple pumping method to increase the effective population of cold atoms in the clock state and investigate the factors which affect the pumping efficiency in cold atom *** report the theory and demonstrate the corresponding experiment in an ^(87)Rb integrating sphere cold atom *** experimental results show that the population of cold atoms in the Zeeman sublevel|F=2,mF=0>is approximately 1.62 times that of the result using optical pumping *** method can also be applied to increase the effective population in any one of the target Zeeman sublevels in other cold atom systems.

关键词： optical pumping Zeeman sublevels atomic utilization

A self-healing coating based on facile pH-responsive nanocontainers for corrosion protection of magnesium alloy

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Journal of Magnesium and Alloys 2022年第3期10卷 904-919页

作者： Yuejun ouyang Lin-xin Li Zhi-Hui Xie Lili Tang Fuhui Wang chuan-Jian Zhong Hunan Engineering Laboratory for Preparation Technology of Polyvinyl Alcohol(PVA)Fiber Material Huaihua UniversityHuaihua 418000PR China Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province/Institute of Synthesis and Application of Functional Materials College of Chemistry and Chemical EngineeringChina West Normal UniversityNanchong 637002PR China Shenyang National Laboratory for Materials Science Northeastern University3-11 Wenhua RoadShenyang 110819PR China Department of Chemistry State University of New York at BinghamtonBinghamtonNY 13902USA

The preparation of pH-responsive nanocontainers by typical silane modification of the mesoporous silica nanoparticle(MSN)surface is usually high-cost,complex,and time-consuming,which remains a great challenge for effective corrosion protection of magnesium ***,a new strategy to construct pH-responsive nanocontainers(MSN-MBT@LDH)is *** nanocontainers consist of corrosion inhibitor(2-mercaptobenzothiazole,MBT)loaded MSN core and layered double hydroxide(LDH)nanosheet shell serving as *** successful loading of MBT and encapsulation by LDH nanosheets were confirmed by a series of characterization such as scanning transmission electron microscopy coupled with energy dispersive X-ray spectroscopy(STEM-EDS)and N2 adsorption/desorption *** pH-responsive feature of the nanocontainers was demonstrated by determination of the MBT concentration in buffer solutions with different pH values.A smart corrosion protection system on Mg alloy is obtained by incorporating the synthesized nanocontainers into a self-assembled nanophase particle(SNAP)*** electrochemical tests and visual observations show that the hybrid coating has the best barrier properties and robustness in corrosion protection in NaCl corrosive solutions in comparison with the control *** present method simplifies the synthesis processes of nanocontainers and eliminates the potential detrimental effect of excess gatekeepers on the *** findings provide new insights into the preparation of scalable *** self-healing coatings are expected to have widespread applications for corrosion protection of Mg alloy and other metals.

关键词： Mg alloy Coating Corrosion Layered double hydroxide Nanocontainer.

Graphene Aerogel Composites with Self‑Organized Nanowires‑Packed Honeycomb Structure for Highly Efficient Electromagnetic Wave Absorption

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Nano-Micro Letters 2025年第2期17卷 533-547页

作者： Xiao You Huiying ouyang Ruixiang Deng Qiuqi Zhang Zhenzhong xing Xiaowu Chen Qingliang Shan Jinshan Yang Shaoming Dong State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050People’s Republic of China Key Laboratory of Inorganic Coating Materials CAS Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050People’s Republic of China Structural Ceramics and Composites Engineering Research Center Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050People’s Republic of China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049People’s Republic of China School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210People’s Republic of China School of Materials Science and Engineering Zhejiang Sci-Tech UniversityHangzhou 310018People’s Republic of China University of Chinese Academy of Sciences Beijing 100039People’s Republic of China

With vigorous developments in nanotechnology,the elaborate regulation of microstructure shows attractive potential in the design of electromagnetic wave ***,a hierarchical porous structure and composite heterogeneous interface are constructed successfully to optimize the electromagnetic loss *** macro–micro-synergistic graphene aerogel formed by the ice template‑assisted 3D printing strategy is cut by silicon carbide nanowires(SiC_(nws))grown in situ,while boron nitride(BN)interfacial structure is introduced on graphene *** unique composite structure forces multiple scattering of incident EMWs,ensuring the combined effects of interfacial polarization,conduction networks,and magnetic-dielectric ***,the as-prepared composites present a minimum reflection loss value of−37.8 dB and a wide effective absorption bandwidth(EAB)of 9.2 GHz(from 8.8 to 18.0 GHz)at 2.5 ***,relying on the intrinsic high-temperature resistance of SiC_(nws) and BN,the EAB also remains above 5.0 GHz after annealing in air environment at 600℃ for 10 h.

关键词： Hierarchical porous structure Interface High-temperature resistance Graphene aerogel composites Electromagnetic wave absorption

A drag force formula for heterogeneous granular flow systems based on finite average statistical method

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Particuology 2021年第2期19卷 94-107页

作者： xin Li Jie ouyang Xiaodong Wang Panpan Chu School of Mathematics and Statistics Northwestern Polytechnical UniversityXi’an 710129China

The existing drag models are mostly based on the assumption of homogenous ***,the use of a homogeneous drag model to predict a heterogeneous granular flow system will cause a *** this study,we developed a drag force model based on the assumption of heterogeneous *** prevent weakening of the heterogeneous characteristics in the drag force formula,we propose a finite average statistical method to filter the information of the heterogeneous granular *** filtered information was used to fit the modified drag formula,which can reflect the heterogeneity of the granular cluster considering different configurations.A comparison shows that the new proposed drag formula filtered by the finite average statistical method fits well with energy minimization multi-scale simulation results.

关键词： Granular flow Drag force Heterogeneous Lattice Boltzmann method Finite average statistical method

Landslide dynamic process and parameter sensitivity analysis by discrete element method: the case of Turnoff Creek rock avalanche

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Journal of Mountain Science 2020年第7期17卷 1581-1595页

作者： An Hui-cong ouyang Chao-jun Zhao chuan Zhao Wei Key Laboratory of Mountain Hazards and Earth Surface Processes Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu610041China CAS Center for Excellence in Tibetan Plateau Earth Sciences Beijing100101China University of Chinese Academy of Sciences Beijing100049China Sichuan Academy of Water Conservancy Chengdu610072China

The great diversity and complexity of geological hazards in terms of flowing materials,environment,triggering mechanisms and physical processes during the flow bring great difficulties to the numerical parameter selection for the discrete element *** order to identity the significance of individual parameters on the landslides dynamic process and provide valuable contribution to the runout analysis of similar landslide,the dynamic process and associated microscopic mechanism of the Turnoff Creek rock avalanche in Canada are *** present numerical results are compared with the field survey data and the results of depth-integrated continuum *** final deposit range matches well with the field survey *** is illustrated that the discrete element method is robust and feasible to capture the dynamic characteristics of large rock avalanche over a complex ***,a new method to assess the landslide hazard level based on the discrete element method is *** to the parameter sensitivity analysis,it is demonstrated that the basal friction coefficient and bond strength are essential to the final deposit while rolling coefficient and restitution coefficient have little effects on it.

关键词： Discrete element method Contact model Numerical modeling Rock avalanche Geological hazard assessment Parameter analysis

Simulation study on cuttings transport of the backreaming operation for long horizontal section wells

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Petroleum Science 2024年第2期21卷 1149-1170页

作者： Yu-Fei Chen Hui Zhang Wen-xin Wu Jun Li Yong ouyang Zong-Yu Lu De-xin Ma Yong-chuan Wu Jun-Bo Liu Ke-Rou Liu Zhuo-xin Dong China University of Petroleum(Beijing) Beijing102249China Beijing Normal University at Zhuhai Experimental and Practical Education Innovation CenterZhuhai519087GuangdongChina Oil&Gas Technology Research Institute of PetroChina Changqing Oilfield Company Xi'an710016ShaanxiChina PetroChina xinjiang Oilfield Company Karamay834002XinjiangChina China Oilfield Services Ltd. Tianjin300459China

The backreaming operation plays a significant role in safe drilling for horizontal wellbores, while it may cause severe stuck pipe accidents. To lower the risk of the stuck pipe in backreaming operations, the mechanism of cuttings transport needs to be carefully investigated. In this research, a transient cuttings transport with multiple flow patterns model is developed to predict the evolution of cuttings transported in the annulus while backreaming. The established model can provide predictions of the distribution of cuttings bed along the wellbore considering the bulldozer effect caused by large-size drilling tools(LSDTs). The sensitivity analyses of the size of LSDTs, and backreaming operating parameters are conducted in Section 4. And a new theory is proposed to explain the mechanism of cuttings transport in the backreaming operation, in which both the bit and LSDTs have the “cleaning effect” and “plugging effect”.The results demonstrate that the cuttings bed in annuli is in a state of dynamic equilibrium, but the overall trend and the distribution pattern are obvious. First, larger diameters and longer drilling tools could lead to a higher risk of the stuck pipe. Second, we find that it is not the case that the higher flow rate is always better for hole cleaning, so three flow-rate intervals are discussed separately under the given conditions. When the “dangerous flow rate”(35 L/s in Case 4),the higher the flow rate, the better the cleaning effect of cuttings beds. Third, an interval of tripping velocity called “dangerous velocity” is proposed, in which the cuttings bed accumulation near the LSDTs is more serious than

关键词： Backreaming Stuck pipe Hole cleaning Transient solid transport Multiple flow patterns

Curve length estimation based on cubic spline interpolation in gray-scale images

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Journal of Zhejiang University-Science C(Computers and Electronics) 2013年第10期14卷 777-784页

作者： Zhen-xin WANG Ji-hong ouyang College of Computer Science and Technology Jilin University MOE Key Laboratory of Symbolic Computation and Knowledge Engineering Jilin University

This paper deals with a novel local arc length estimator for curves in gray-scale *** method first estimates a cubic spline curve fit for the boundary points using the gray-level information of the nearby pixels,and then computes the sum of the spline segments’*** this model,the second derivatives and y coordinates at the knots are required in the computation;the spline polynomial coefficients need not be computed *** provide the algorithm pseudo code for estimation and preprocessing,both taking linear *** shows that the proposed model gains a smaller relative error than other state-of-the-art methods.

关键词： Arc length estimation Cubic spline interpolation Gray-scale image Local algorithm

低空经济助推新质生产力的运行机理与路径选择

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新疆师范大学学报（哲学社会科学版） 2025年第1期46卷 118-131页

作者：欧阳日辉中央财经大学中国互联网经济研究院北京100081

低空经济是以低空飞行活动为牵引,以有人驾驶和无人驾驶航空器为主要载体,通过技术创新和模式创新推动相关产业融合发展的新型综合性经济形态。低空经济涉及领域和行业多、应用场景多、创新之处多、产业链条长、带动效应强,具有创新驱... 详细信息

低空经济是以低空飞行活动为牵引,以有人驾驶和无人驾驶航空器为主要载体,通过技术创新和模式创新推动相关产业融合发展的新型综合性经济形态。低空经济涉及领域和行业多、应用场景多、创新之处多、产业链条长、带动效应强,具有创新驱动性、空间依赖性、跨界融合性、辐射带动性等技术—经济特征。低空经济通过场景牵引、跨界融合、协同治理,聚焦应用场景,打造低空多场景应用,推动“低空+”物流配送、“低空+”城市空中交通、“低空+”旅游、“低空+”应急救援等规模化发展,在技术创新与制度创新相互嵌套、协同治理的基础上实现健康发展。当前,各地各部门积极抢占低空经济新赛道,通过建设智能互联高效的基础设施、加快低空智能互联航行技术创新、完善产业链增强低空产业韧性和安全等举措因地制宜打造融合创新的应用场景。为促进低空经济发展,应加强产业政策引导与支持,支持低空经济技术创新与研发,推动跨界融合与应用场景创新,完善产业链配套服务体系。

关键词：低空经济新质生产力应用场景科技创新产业创新

New approach to develop a 3D non-isothermal computational framework for injection molding process based on level set method

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Chinese Journal of Chemical Engineering 2016年第7期24卷 832-842页

作者： xin Zhuang Jie ouyang Chuntao Jiang Qingsheng Liu Department of Applied Mathematics Northwestern Polytechnical University

The simulation of three-dimensional （3D） non-isothermal, non-Newtonian fluid filling process is an extremely difficult task and remains a challenging problem, which includes polymer melt flow with free surface coupled with transient heat transfer. This paper presents a full 3D non-isothermal two-phase flow model to predict the complex flow in melt filling process, where the Cross-WLF model is applied to characterize the rheological behav- ior of polymer melt. The governing equations are solved using finite volume method with SIMPLEC algorithm on collocated grids and the melt front is accurately captured by a high resolution level set method. A domain exten- sion technique is adopted to deal with the complex cavities, which greatly reduces the computational burden. To verify the validity of the developed 3D approach, the melts filling processes in two thin rectangular cavities （one of them with a cylindrical insert） are simulated. The predicted melt front interfaces are in good agreement with the experiment and commercial software prediction. For a case with a rather complex cavity, the dynamic filling process in a hemispherical shell is successfully simulated. All of the numerical results show that the developed numerical procedure can provide a reasonable orediction for injection molding process.

关键词： Injection moldingNon-isothermalFinite voIume/SIMPLEC methodDomain extension techniqueHigh resolution level set method