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Atomic transport dynamics in crossed optical dipole trap

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Chinese Physics B 2024年第7期33卷 293-301页

作者：彭鹏张正熙樊耀塬殷国玲毛德凯陈徐宗熊炜周小计 State Key Laboratory of Advanced Optical Communication System and Network School of ElectronicsPeking UniversityBeijing 100871China Institute of Carbon-based Thin Film Electronics Peking UniversityTaiyuan 030012China State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Opto-ElectronicsShanxi UniversityTaiyuan 030006China

We study the dynamical evolution of cold atoms in crossed optical dipole trap theoretically and experimentally. The atomic transport process is accompanied by two competitive kinds of physical mechanics, atomic loading and atomic *** loading process normally is negligible in the evaporative cooling experiment on the ground, while it is significant in preparation of ultra-cold atoms in the space station. Normally, the atomic loading process is much weaker than the atomic loss process, and the atomic number in the central region of the trap decreases monotonically, as reported in previous research. However, when the atomic loading process is comparable to the atomic loss process, the atomic number in the central region of the trap will initially increase to a maximum value and then slowly decrease, and we have observed the phenomenon first. The increase of atomic number in the central region of the trap shows the presence of the loading process, and this will be significant especially under microgravity conditions. We build a theoretical model to analyze the competitive relationship, which coincides with the experimental results well. Furthermore, we have also given the predicted evolutionary behaviors under different conditions. This research provides a solid foundation for further understanding of the atomic transport process in traps. The analysis of loading process is of significant importance for preparation of ultra-cold atoms in a crossed optical dipole trap under microgravity conditions.

关键词： cold atom crossed optical dipole trap transport process

AN EMPIRICAL FEASIBILITY STUDY OF SOCIETAL RISK CLASSIFICATION TOWARD BBS POSTS

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Journal of Systems Science and Systems Engineering 2018年第6期27卷 709-726页

作者： Jindong Chen xiaoji zhou Xijin Tang School of Economics and Management Beifing Information Science &Technology University Beifing 100192 China China Academy of Aerospace Systems Science and Engineering Beijing 100048 China Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China Beijing Key Lab of Green Development Decision Based on Big Data Beijing 100192 China University of Chinese Academy of Sciences Beijing 100049 China

Societal risk classification is the fundamental issue for online societal risk monitoring. To show the challenge and feasibility of societal risk classification toward BBS posts, an empirical analysis is implemented in this paper. Through effectiveness analysis, Support Vector Machine based on Bag-Of-Words （BOW-SVM） is adopted for challenge validation, and the distributed document embeddings of BBS posts generated by Paragraph Vector are applied to feasibility study. Based on BOW-SVM, cross-validations of BBS posts labeled by different groups and annotators are conducted. The big fluctuation of cross-validation results indicates the differences of individual risk perceptions, which brings more challenges to societal risk classification. Furthermore, based on the distributed document embeddings of BBS posts, the pairwise similarities of more than 300 thousands BBS posts from different societal risk categories are compared. The higher similarities of BBS posts in the same societal risk category reveal that BBS posts in the same societal risk category share more features than BBS posts in different categories, which manifests the feasibility of societal risk classification of BBS posts, and also reflects the possibility to improve the performance of societal risk monitoring.

关键词： Societal risk classification Tianya Forum cross validation pairwise similarity individual risk perception

高速公路拥堵工况下自动驾驶车辆切入场景测试集构建与安全性评估

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汽车技术 2024年第4期 7-14页

作者：石帅坤赵丹马明月苗泽霖周孝吉中国人民公安大学北京100038 公安部道路交通安全研究中心北京100062 中国汽车工程研究院股份有限公司重庆401122

为评估中国高速公路拥堵工况下自动驾驶汽车在切入场景中的安全风险,从自然驾驶数据集中提取64个切入样本,采用六层次模型和相关性分析方法确定场景要素范围,通过抽样生成1 000个测试用例并构建安全评估指标体系分析车辆运行安全,运用... 详细信息

为评估中国高速公路拥堵工况下自动驾驶汽车在切入场景中的安全风险,从自然驾驶数据集中提取64个切入样本,采用六层次模型和相关性分析方法确定场景要素范围,通过抽样生成1 000个测试用例并构建安全评估指标体系分析车辆运行安全,运用随机森林算法确定引发风险的关键因素。结果表明:在1 000个测试用例中,风险场景占比5.3%,纵向相对速度是导致风险的关键要素;拥堵工况下,环境车辆速度低于自动驾驶车辆速度23%时形成高风险切入场景,该指标可作为拥堵切入场景下自动驾驶汽车识别风险的预测指标,亦可用于该场景下的事故责任认定。

关键词：高速公路拥堵工况自动驾驶汽车切入场景运行安全随机森林

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土建工程绿色施工管理创新研究

现代工程科技 2024年第8期3卷 97-100页

作者：宋丹周小记马云红日照天泰建筑安装工程有限公司山东日照276800 日照凯泰门窗科技有限公司山东日照276826

探讨了如何通过创新土建工程管理和绿色施工策略,实现建设项目与环境保护的协调发展。为减少建设对环境的影响,同时提高资源利用效率,需采用环保材料、节能措施并优化施工工艺,对此开展研究。结合创新管理的绿色施工模式显著提高了工程... 详细信息

探讨了如何通过创新土建工程管理和绿色施工策略,实现建设项目与环境保护的协调发展。为减少建设对环境的影响,同时提高资源利用效率,需采用环保材料、节能措施并优化施工工艺,对此开展研究。结合创新管理的绿色施工模式显著提高了工程质量和施工效率,同时减少了资源浪费和环境污染。绿色施工管理为土建工程带来了一种新的、环保且经济的模式,为行业的可持续发展树立了新标杆。

关键词：土建工程管理创新绿色施工管理

Improve the performance of interferometer with ultra-cold atoms

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Chinese Physics B 2021年第1期30卷 42-55页

作者： Xiangyu Dong Shengjie Jin Hongmian Shui Peng Peng xiaoji zhou State Key Laboratory of Advanced Optical Communication Systems and Networks Department of ElectronicsPeking UniversityBeijing 100871China

Ultra-cold atoms provide ideal platforms for *** macroscopic matter-wave property of ultra-cold atoms leads to large coherent length and long coherent time,which enable high accuracy and sensitivity to ***,we review our efforts to improve the performance of the *** demonstrate a shortcut method for manipulating ultra-cold atoms in an optical *** with traditional ones,this shortcut method can reduce the manipulation time by up to three orders of *** construct a matter-wave Ramsey interferometer for trapped motional quantum states and significantly increase its coherence time by one order of magnitude with an echo technique based on this *** have also been made to enhance the resolution by multimode *** of a noise-resilient multi-component interferometer shows that increasing the number of paths could sharpen the peaks in the time-domain interference fringes,which leads to a resolution nearly twice compared with that of a conventional double-path two-mode *** the shortcut method mentioned above,improvement of the momentum resolution could also be fulfilled,which leads to atomic momentum patterns less than 0.6hkL. To identify and remove systematic noises,we introduce the methods based on the principal component analysis (PCA) that reduce the noise in detection close to the 1/√2 of the photon-shot noise and separate and identify or even eliminate ***,we give a proposal to measure precisely the local gravity acceleration within a few centimeters based on our study of ultracold atoms in precision measurements.

关键词： precision measurement ultra-cold atoms atom interferometer gravity measurements

MAN-MACHINE COLLABORATED KNOWLEDGE CREATION IN HWMSE

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Journal of Systems Science and Systems Engineering 2005年第4期14卷 462-475页

作者： Jingyuan YU xiaoji zhou Shan FENG Beijing Institute of Information and Control PO. Box 842 Beijing 1000371 Chian Huazhong University of Science and Technology

The target of Hall for Workshop of Meta-synthetic Engineering （HWMSE） is to organically combine the human expert systems, machine systems and knowledge systems so as to realize meta-syntheses. The availability of HWMSE embodies in capabilities of knowledge using and knowledge creation. In HWMSE the knowledge systems could be classed into two types： general knowledge system and object knowledge system. A highly strong and continually accumulated object knowledge system is essential for complex system problem solving. Systematic study of the object system is the foundation for knowledge system construction in HWMSE. It is important to design the knowledge system as a whole for systematic research while at the meanwhile open for accumulation through utilization. Case of object knowledge system construction and utilization in the project Research on the Man-machine Collaborated HWMSE Supporting Macroeconomic Policy Making is discussed.

关键词： Meta-synthesis HWMSE knowledge system macroeconomics

Flower-like Bi_2WO_6/ZnO composite with excellent photocatalytic capability under visible light irradiation

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Chinese Journal of Catalysis 2018年第4期39卷 810-820页

作者： Juan Cheng Yi Shen Kuan Chen Xi Wang Yongfu Guo xiaoji zhou Renbi Bai Center for Separation and Purification Materials&Technologies Suzhou University of Science and TechnologySuzhou 215009JiangsuChina Jiangsu Collaborative Innovation Center of Water Treatment Technology and Material Suzhou 215009JiangsuChina

The photocatalytic ability of ZnO is improved through the addition of flower‐like Bi2WO6 to prepare a Bi2WO6/ZnO composite with visible light *** composite is characterized by X‐ray diffraction,transmission electron microscopy,scanning electron microscopy with UV–vis diffuse reflectance spectroscopy,X‐ray photoelectron spectroscopy and N2 adsorption‐desorption *** modification,the band gap energy of Bi2WO6/ZnO is reduced from 3.2 eV for ZnO to 2.6 *** visible light irradiation,the Bi2WO6/ZnO composite shows an excellent photocatalytic activity for degrading methylene blue(MB)and *** photo‐degradation efficiencies of(0.3:1)Bi2WO6/ZnO for MB and tetracycline are approximately 246 and 4500 times higher than those of bare ZnO,respectively,and correspondingly,the photo‐degradation rates for the two pollutants are approximately 120 and 200 times higher than those with bare ZnO,***,the photocatalyst of(0.3:1)Bi2WO6/ZnO exhibits a higher transient photocurrent density of approximately 4.5μA compared with those of bare Bi2WO6 and ZnO *** successful recombination of Bi2WO6 and ZnO enhances the photocatalytic activity and reduces the band gap energy of ZnO,which can be attributed to the effective separation of electron–hole *** species trapping experiments display that[O2]-is the major species involved during photocatalysis rather than·OH and h+.This study provides insight into designing a meaningful visible‐light‐driven photocatalyst for environmental remediation.

关键词： Bismuth tungstate Zinc oxide Photocatalysis Methylene blue Antibiotics

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高校院级分析测试平台构建与管理探讨

实验室科学 2024年第1期27卷 185-188页

作者：王磊张磊李大鹏秦宏兵周晓吉刘婷婷苏州科技大学、江苏省环境科学与工程重点实验室、环境科学与工程学院江苏苏州215000

仪器设备使用与管理的信息化是当前高校院所实现开放共享服务的重要途径。结合以江苏省环境科学与工程重点实验室为依托的环境科学与工程学院分析测试平台预约系统的构建案例,介绍了系统的构建思路、组成模块、运行方式及管理模式等内容... 详细信息

仪器设备使用与管理的信息化是当前高校院所实现开放共享服务的重要途径。结合以江苏省环境科学与工程重点实验室为依托的环境科学与工程学院分析测试平台预约系统的构建案例,介绍了系统的构建思路、组成模块、运行方式及管理模式等内容,介绍了院级仪器设备管理平台现状、院级分析测试系统的构建、管理运行模式探索等内容。院级系统的建立实现了对校级仪器设备信息化管理的补充,实现了不同教研室和科研课题组对仪器使用与管理的细化,有效促进了科研基础设施和仪器设备共享使用的全面化施行。

关键词：仪器设备预约管理开放共享二级学院

Quantum precision measurement of two-dimensional forces with 10^(-28)-Newton stability

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Science Bulletin 2022年第22期67卷 2291-2297页

作者： Xinxin Guo Zhongcheng Yu Fansu Wei Shengjie Jin Xuzong Chen Xiaopeng Li Xibo Zhang xiaoji zhou State Key Laboratory of Advanced Optical Communication System and Network School of ElectronicsPeking UniversityBeijing 100871China State Key Laboratory of Surface Physics Key Laboratory of Micro and Nano Photonic Structures(MOE)and Department of PhysicsFudan UniversityShanghai 200433China Institute for Nanoelectronic Devices and Quantum Computing Fudan UniversityShanghai 200433China Shanghai Qi Zhi Institute AI TowerXuhui DistrictShanghai 200232China Shanghai Research Center for Quantum Sciences Shanghai 201315China International Center for Quantum Materials School of PhysicsPeking UniversityBeijing 100871China Institute of Advanced Functional Materials and Devices Shanxi UniversityTaiyuan 030031China

High-precision sensing of vectorial forces has broad impact on both fundamental research and technological applications such as the examination of vacuum fluctuations and the detection of surface roughness of *** years have witnessed much progress on sensing alternating electromagnetic forces for the rapidly advancing quantum technology-orders of magnitude improvement has been accomplished on the detection sensitivity with atomic sensors,whereas such high-precision measurements for static electromagnetic forces have rarely been ***,based on quantum atomic matter waves confined by a two-dimensional optical lattice,we perform precision measurement of static electromagnetic forces by imaging coherent wave mechanics in the reciprocal *** lattice confinement causes a decoupling between real-space and reciprocal dynamics,and provides a rigid coordinate frame for calibrating the wavevector accumulation of the matter *** that we achieve a stateof-the-art sensitivity of 2.30(8)×10^(-26) N/√***-term stabilities on the order of 10^(-28) N are observed in the two spatial components of a force,which allows probing atomic Van der Waals forces at one millimeter *** a further illustrative application,we use our atomic sensor to calibrate the control precision of an alternating electromagnetic force applied in the *** developments of this method hold promise for delivering unprecedented atom-based quantum force sensing technologies.

关键词： Quantum precision measurement Bose–Einstein condensates Optical lattices Ultracold atoms Force sensor