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Temperature Dependence of Optically Erased Two-Wave Mixing in Ce:KNSBN

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Chinese Physics Letters 1998年第5期15卷 345-347页

作者： LIU Jin-song LU Ke-qing LIANG Chang-hong ZHANG Du-ying tang tian-tong Department of Applied Physics Xidian UniversityXi’an 710071 Institute of Electronic and Information Engineering Jiaotong UniversityXi’an 710049

The intensity response of an optically erased photorefractive two-wave mixing to the erase beam is studied by using the coupling wave equation and the band-transport *** concepts of response strength and the minimum response intensity are introduced and their temperature dependence is investigated.A 2-fold increase in the response strength and 4-fold decrease in minimum response intensity have been experimentally observed in Ce:KNSBN at 633 nm when the crystal temperature is raised from 320 to *** experimental results are in agreement with theoretical analysis and show that the response property can be improved by changing the crystal temperature.

关键词： temperature crystal wave

Steady-State Screening-Photovoltaic Spatial Solitons in the Biased Photorefractive-Photovoltaic Crystals

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Chinese Physics Letters 2001年第2期18卷 233-235页

作者： LU Ke-Qing ZHANG Yan-Peng tang tian-tong LU Zhi-Xian LIU Lin Department of Electronic Science and Technology Xi’an Jiaotong UniversityXi’an 710049 State Key Laboratory of Transient Optics Technology Xi’an Institute of Optics&Precision MechanicsChinese Academy of SciencesXi’an 710068 Department of Applied Physics Xidian UniversityXi’an 710071 Department of Applied Physics Northwestern Polytechnical UniversityXi’an 710072

The theory of the screening-photovoltaic solitons is improved in biased photorefractive-photovoltaic *** the photovoltaic effect is negligible,the screening-photovoltaic solitons are the screening ones,and their space-charge field is the space-charge field of the screening *** the external field is absent,the screening-photovoltaic solitons are the photovoltaic ones on the open-and closed-circuit conditions,and their space-charge field is of the photovoltaic *** also show theoretically that the screening and the photovoltaic solitons on the open-and closed-circuit conditions may be studies together as the screening-photovoltaic solitons.

关键词： solitons negligible charge

Preparation of Self-limiting Heating Cables with Excellent Processability, Mechanical Properties and PTC Effect via Thermal and Electrical Treatments

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Chinese Journal of Polymer Science 2024年第4期42卷 511-520页

作者： tian-Hao Yang tong Wu Qiang Fu State Key Laboratory of Polymer Materials Engineering College of Polymer Science and EngineeringSichuan UniversityChengdu610065China State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan UniversityChengdu610065China

Polymer/conductive filler composites have been widely used for the preparation of self-limiting heating cables with the positive temperature coefficient (PTC) effect. The control of conductive filler distribution and network in polymer matrix is the most critical for performance of PTC materials. In order to compensate for the destruction of the filler network structure caused by strong shearing during processing, an excessive conductive filler content is usually added into the polymer matrix, which in turn sacrifices its processability and mechanical properties. In this work, a facile post-treatment of the as-extruded cable, including thermal and electrical treatment to produce high-density polyethylene (HDPE)/carbon black (CB) cable with excellent PTC effect, is developed. It is found for the as-extruded sample, the strong shearing makes the CB particles disperse uniformly in HDPE matrix, and 25 wt% CB is needed for the formation of conductive paths. For the thermal-treated sample, a gradually aggregated CB filler structure is observed, which leads to the improvement of PTC effect and the notable reduction of CB content to 20 wt%. It is very interesting to see that for the sample with combined thermal and electrical treatment, CB particles are agglomerated and oriented along the electric field direction to create substantial conductive paths, which leads to a further decrease of CB content down to 15 wt%. In this way, self-limiting heating cables with excellent processability, mechanical properties and PTC effect have simultaneously been achieved.

关键词： Self-limiting heating cables Positive temperature coefficient Thermal treatment Electrical treatment

Topologically protected entanglement switching around exceptional points

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Light(Science & Applications) 2024年第8期13卷 1631-1644页

作者： Zan tang tian Chen Xing tang Xiangdong Zhang Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements of Ministry of Education Beijing Key Laboratory of Nanophotonics&Ultrafine Optoelectronic SystemsSchool of PhysicsBeijing Institute of Technology100081 BeijingChina

The robust operation of quantum entanglement states is crucial for applications in quantum information,computing,and communications^(1–3).However,it has always been a great challenge to complete such a task because of decoherence and ***,we propose theoretically and demonstrate experimentally an effective scheme to realize robust operation of quantum entanglement states by designing quadruple degeneracy exceptional *** encircling the exceptional points on two overlapping Riemann energy surfaces,we have realized a chiral switch for entangled states with high *** to the topological protection conferred by the Riemann surface structure,this switching of chirality exhibits strong robustness against perturbations in the encircling ***,we have experimentally validated such a scheme on a quantum walk *** work opens up a new way for the application of non-Hermitian physics in the field of quantum information.

关键词： exceptional quantum Riemann

Forced boiling of nonazeotropic immiscible mixture in a supercapillary microchannel array for ultra-high heat flux removal with chip junction temperature below 85℃

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Science China(Technological Sciences) 2024年第5期67卷 1364-1380页

作者： SUN Bo BAO YuChen tian tong LI Ji School of Engineering Science University of Chinese Academy of SciencesBeijing100049China Laboratory of Advanced Thermal Management Technologies School of Engineering ScienceUniversity of Chinese Academy of SciencesBeijing100049China

In this study,a structure-optimized two-phase microchannel heat sink with sintered submicron nucleation sites was developed and *** copper-based microchannels had a rectangular cross-section with an equivalent hydraulic diameter of 222μ*** subcooled flow boiling characteristics were comprehensively compared between pure HFE-7100 and a non-azeotropic,immiscible binary mixture of HFE-7100 and water,considering heating areas of 1 and 5 cm^(2).The total heating power input to the test section were 100–1500 and 250–3000 W for a 1 and 5 cm^(2)heat source,respectively,with a flow rate ranging from 50 to150 L/*** to pure HFE-7100,the non-azeotropic immiscible binary mixture of HFE-7100/water in the sintered porous microchannels exhibited a much higher overall heat transfer coefficient and lower power *** maintain the junction temperature of a high power electronic chip below 85℃,the proposed supercapillary microchannel heat sink could effectively dissipate the heat flux of 1275 W/cm^(2)over 1 cm^(2)heat source and 500 W/cm^(2)over 5 cm^(2)heat *** addition,the volume ratio of the binary mixture strongly influence the two-phase flow heat transfer *** optimal volume ratio exist in terms of the thermal resistance–pumping power minimization(HFE-7100:water=2:8 is recommended in this study).The findings of this investigation on the flow boiling properties of non-azeotropic immiscible mixtures help fill a gap in the related field.

关键词： microchannel sintered powder coating submicron nucleation cavities nonazeotropic immiscible ultra-high heat flux

Model-driven path planning for robotic plasma cutting of branch pipe with single Y-groove based on pipe-rotating scheme

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Advances in Manufacturing 2024年第1期12卷 94-107页

作者： Yan Liu Qiu tang Xin-Cheng tian School of Control Science and Engineering Shandong UniversityJinan250061People’s Republic of China Engineering Research Center of Intelligent Unmanned System Ministry of EducationJinan250061People’s Republic of China School of Mechanical and Electronic Engineering Shandong Jianzhu UniversityJinan250101People’s Republic of China

The automatic cutting of intersecting pipes is a challenging task in *** improved automation and accuracy,this paper proposes a model-driven path planning approach for the robotic plasma cutting of a branch pipe with a single ***,it summarizes the intersection forms and introduces a dual-pipe intersection *** on this model,the moving three-plane structure(a description unit of the geometric characteristics of the intersecting curve)is constructed,and a geometric model of the branch pipe with a single Y-groove is ***,a novel mathematical model for plasma radius and taper compensation is ***,the compensation model and groove model are integrated by establishing movable ***,to prevent collisions between the plasma torch and workpiece,the torch height is planned and a branch pipe-rotating scheme is *** the established models and moving frames,the planned path description of cutting robot is provided in this novel *** accuracy of the proposed method is verified by simulations and robotic cutting experiments.

关键词： Automatic groove cutting of intersecting pipes Model-driven robot path planning Plasma beam radius and taper compensation

2020—2022年海口市城区大气PM_(2.5)中重(类)金属组成及来源解析

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环境卫生学杂志 2024年第10期14卷 802-811页

作者：何昌华杨夕伍燕春胡伟封丹唐天统林天符桂林李永忠梅振坤曾月海南省疾病预防控制中心公共卫生研究所海口571129 海南省预防医学科学院海口571129 海南医科大学公共卫生学院天津大学地球系统科学学院表层地球系统科学研究院海南省环境科学研究院文昌市疾病预防控制中心公共卫生科

目的探析海口市主城区大气PM_(2.5)中重(类)金属污染的组成和主要来源。方法于2020—2022年对海口市主城区进行逐月定期(10—16日)采集大气PM_(2.5)样品,每日持续采样时间不少于22 h;利用电感耦合等离子体质谱法(ICP-MS)测量PM_(2.5)样... 详细信息

目的探析海口市主城区大气PM_(2.5)中重(类)金属污染的组成和主要来源。方法于2020—2022年对海口市主城区进行逐月定期(10—16日)采集大气PM_(2.5)样品,每日持续采样时间不少于22 h;利用电感耦合等离子体质谱法(ICP-MS)测量PM_(2.5)样品中25种重(类)金属成分;对PM_(2.5)中检出率较高的16种重(类)金属成分采用正定矩阵因子分解模型(PMF)解析主要污染来源。结果2020—2022年海口市主城区大气PM_(2.5)质量浓度范围4.00~64.00μg/m^(3),均数(􀭰x±s)为(20.48±12.88)μg/m^(3)、中位数(M)17.00μg/m^(3)及四分位数间距(IQR)14.25μg/m^(3),年度间PM_(2.5)24小时平均浓度差异不具有统计学意义(χ^(2)=1.24,P>0.05);不同季节PM_(2.5)24小时平均浓度差异具有统计学意义(χ^(2)=44.86,P秋季>春季>夏季;16种重(类)金属的质量浓度范围为0.01~1008.00 ng/m^(3),质量浓度M值由高到低依次为Fe>Al>Zn>Mn>Pb>Ba>Cu>Sr>Ni>Se>V>As>Sn>Cr>Cd>Li。PMF模型解析结果表明,PM_(2.5)中16种重(类)金属污染主要贡献来源以道路及土壤尘源(49.82%)和交通尾气源(36.96%)为主,次之贡献源有混合燃烧源(9.61%)、建材施工尘源(2.51%)和船舶燃油源(1.10%)。结论2020—2022年海口市大气PM_(2.5)质量浓度均未超过我国《环境空气质量标准》(GB 3095-2012)24小时平均浓度二级限值(75μg/m^(3))水平,PM_(2.5)中重(类)金属构成主要以Fe、Al、Zn、Mn和Pb元素为主,其主要贡献源是道路及土壤尘源和交通尾气源。

关键词：海口细颗粒物重(类)金属源解析

Photo-induced grease/oil switched lubricant for friction regulation

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Friction 2024年第8期12卷 1696-1706页

作者： Zheng ZHANG Shuangxi tang Liran MA Yu tian State Key Laboratory of Tribology in Advanced Equipment Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China

Controllable friction regulation has drawn much interest in both scientific and industrial *** there have been many researches on friction regulation by many physical fields and chemical ***-sensitive materials are promising because it is relatively easy to change their properties compared with ***,a new kind of photo-induced grease/oil switched lubricant is designed and shows great reversibility under ultraviolet(UV)and visible(Vis)*** viscosity can change more than 50 times under different irradiation,and the coefficients of friction(COFs)obviously increase under Vis irradiation and decrease under UV irradiation,which performs better than those of the common *** to the experimental results,the phenomena are contributed to the break and reconstruction of the three-dimensional network inside the *** a switchable grease/oil state under different irradiation,this work provides a new principle for designing a smart lubricant with controllable friction regulation.

关键词： photo-induced spiropyran switched lubricant friction regulation

Analyzing topics in social media for improving digital twinning based product development

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Digital Communications and Networks 2024年第2期10卷 273-281页

作者： Wenyi tang Ling tian Xu Zheng Ke Yan School of Computer Science and Engineering University of Electronic Science and Technology of ChinaChengdu611731China

Digital twinning enables manufacturers to create digital representations of physical entities,thus implementing virtual simulations for product *** efforts of digital twinning neglect the decisive consumer feedback in product development stages,failing to cover the gap between physical and digital *** work mines real-world consumer feedbacks through social media topics,which is significant to product *** specifically analyze the prevalent time of a product topic,giving an insight into both consumer attention and the widely-discussed time of a *** primary body of current studies regards the prevalent time prediction as an accompanying task or assumes the existence of a preset ***,these proposed solutions are either biased in focused objectives and underlying patterns or weak in the capability of generalization towards diverse *** this end,this work combines deep learning and survival analysis to predict the prevalent time of *** propose a specialized deep survival model which consists of two *** first module enriches input covariates by incorporating latent features of the time-varying text,and the second module fully captures the temporal pattern of a rumor by a recurrent network ***,a specific loss function different from regular survival models is proposed to achieve a more reasonable *** experiments on real-world datasets demonstrate that our model significantly outperforms the state-of-the-art methods.

关键词： Digital twinning Product development Topic analysis Social media