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Micro-fabrication process of vapor cells for chip-scale atomic clocks

Chinese Optics Letters 2019年第4期17卷 10-14页

作者： Yanjun Zhang Yunchao Li xuwen hu Lu Zhang Zhaojun Liu Kaifang Zhang Shihao Mou Shougang zkang Shubin Yan Science and Technology on Electronic Test and Measurement Laboratory North University of China Key Laboratory of Time and Frequency Primary Standards National Time Service Center Chinese Academy of Sciences

As the key part of chip-scale atomic clocks(CSACs), the vapor cell directly determines the volume, stability,and power consumption of the CSAC. The reduction of the power consumption and CSAC volumes demands the manufacture of corresponding vapor cells. This overview presents the research development of vapor cells of the past few years and analyzes the shortages of the current preparation technology. By comparing several different vapor cell preparation methods, we successfully realized the micro-fabrication of vapor cells using anodic bonding and deep silicon etching. This cell fabrication method is simple and effective in avoiding weak bonding strengths caused by alkali metal volatilization during anodic bonding under high ***, the vapor cell D2 line was characterized via optical-absorption resonance. According to the results,the proposed method is suitable for CSAC.

关键词： chip-scale atomic clocks directly determines optical-absorption resonance

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Organic metal matrix Mil-88a nano-enzyme for joint repair in the osteoarthritis mouse model

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FRONTIERS IN BIOENGINEERING AND BIOTECHNOLOGY 2023年 11卷 1164942页

作者： hu, Hao huang, Xu Dai, Yankun Zhu, Kairun Ye, xuwen Meng, Shengdong Zhang, Qing Xie, Xueguan Huaian Second Peoples Hosp Huaian Peoples R China

Introduction: In this paper we tried to conduct a novel nanomaterial strategy to overcome osteoarthritis (OA) in a mouse model. Methods: In this regard, after synthesizing the Mil-88a nanozyme, as a certain Fe-MOF, its toxic effects were detected by CCK-8 method and live-dead staining. The OA model of mouse was constructed, and paraffin sections of joints were taken for histological evaluation. In addition, immunofluorescence and immunohistochemistry were used to identify the OA progression and OARSI was used to evaluate the OA grades. We observed that Mil-88a could be easily synthesized and has high biocompatibility. Results: We observed that Mil-88a could significantly promote the expression of OA anabolism-related genes such as Col2 and also significantly inhibit the expression of OA catabolism-related genes MMP13. Besides, we observed better OARSI score in animals treated with Mil-88a nano-enzyme loading on organic metal matrix. Discussion: Overall, Mil-88a nano-enzyme could be used as a novel strategy to treat OA.

关键词： nano-enzyme osteoarthritis mouse model Mil-88a organic metal

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Initial Assessment of LEO-Augmented GPS RTK in Signal-Degraded Environment

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2020年第7期E103A卷 942-946页

作者： hu, Weisheng Hou, huiling Xie, Zhuochen Liang, xuwen He, Xiaohe Chinese Acad Sci Shanghai Inst Microsyst & Informat Technol Shanghai Peoples R China Univ Chinese Acad Sci Beijing Peoples R China Chinese Acad Sci Shanghai Engn Ctr Microsatellites Shanghai Peoples R China ShanghaiTech Univ Sch Informat Sci & Technol Shanghai Peoples R China

We simulate some scenarios that 2/3 LEO satellites enhance 3/4/5 GPS satellites, to assess LEO-augmented GPS RTK positioning in signal-degraded environment. The e ffects of LEO-augmented GPS RTK in terms of reliabilit... 详细信息

关键词： LEO-augmented RTK signal-degrade environment DIA

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Degradation of bisphenol A in an oxidation system constructed from Mo2C MXene and peroxymonosulfate

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NPJ CLEAN WATER 2022年第1期5卷 66页

作者： Chen, xuwen Gudda, Fredrick Owino hu, Xiaojie Waigi, Michael Gatheru Gao, Yanzheng Nanjing Agr Univ Inst Organ Contaminant Control & Soil Remediat Coll Resources & Environm Sci Nanjing 210095 Peoples R China

The etched Mo2C MXene with a layered structure was characterized as an environmentally friendly catalyst in the bisphenol A (BPA) removal by advanced oxidation. 99.75% of BPA was degraded in the oxidation system constructed using Mo2C MXene and peroxymonosulfate (PMS). The Mo2C MXene was recyclable, with a high removal percentage (89.29%) of BPA after even four cycles. The catalysis of Mo2C MXene on PMS was due to the Mo-deficit vacancy defects. The electron paramagnetic resonance technique and density functional theory (DFT)-based density of states calculations verified defect signals. In addition, the defective Mo2C MXene and PMS have strong binding and electron transfer capabilities. The reactive oxygen species (ROS, including O-2(center dot -), O-1(2), SO4 center dot , and (OH)-O-center dot ) produced by Mo2C MXene activates PMS, leading to BPA degradation. The condensed Fukui function predicted the active sites of the BPA molecule and found that the O1, O2, C3, C4, C6, C12, C15, and C16 sites have higher electrophilic reactivity. The C, C-C bonds, or C4/C16 sites in the isopropyl group connecting the two phenolic rings were attacked first, then further transformed BPA into non-toxic or low toxic small molecule degradation products through a series of reactions such as bond-breaking, addition, hydroxylation, and ring-opening. Moreover, the Mo2C MXene/PMS system has strong applicability in actual water bodies. The study provides valuable insights into PMS activation by two-dimensional MXenes to remove toxic organic pollutants in an aqueous matrix.

关键词： Molecules

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Recovering copper ions from wastewater with chitosan to synthesize lead-free primary explosives

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JOURNAL OF ALLOYS AND COMPOUNDS 2022年 914卷 1页

作者： Liu, xuwen hu, Yan Yang, Caimin Su, Jiaxin Ye, Yinghua Shen, Ruiqi Nanjing Univ Sci & Technol Sch Chem & Chem Engn Nanjing 210094 Peoples R China Minist Ind & Informat Technol Micronano Energet Devices Key Lab Nanjing 210094 Peoples R China

Chitosan (CTS) is a well-known adsorbent capable of absorbing copper ions. It's also a high-quality biomass carbon source. The carbon skeleton formed by the pyrolysis of CTS has outstanding electrical conductivity, which can help copper azide (CA), a new type of primary explosive that's particularly sensitive to electrostatic stimuli, be more electrostatically safe. The CTS-Cu complex is precipitated by using CTS to adsorb and flocculate copper ions in wastewater. To construct the Cu@carbonized chitosan (CCTS) precursor material, the organic ligands in the CTS-Cu complex are calcined into a porous three-dimensional carbon matrix, and the copper ions are transformed into copper nanoparticles embedded in CCTS. The azide reaction converts copper nanoparticles (CuNPs) into high-energy CA. With its good electrical conductivity, CCTS maintains its framework structure and effectively improves the electrostatic safety of composite energetic materials. CA@CCTS has a CA content of 69.7%, an electrostatic ignition energy (E-50) of about 1.19 mJ, and a heat release of 1803.22 J/g. This work takes advantage of CA and CTS's environmental friendliness. CA@CCTS, as a novel lead-free primary explosive, has good electrostatic safety while containing a high proportion of CA. (C) 2022 Elsevier B.V. All rights reserved.

关键词： Chitosan Adsorbent Carbonization Composite energetic materials Copper azide Electrostatic safety

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相干布局囚禁原子钟原子气室内部缓冲气体组分的优化

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激光与光电子学进展 2019年第12期56卷 30-35页

作者：李云超胡旭文张璐刘召军张开放牟仕浩闫树斌张彦军中北大学仪器与电子学院山西太原030051 中北大学仪器科学与动态测试教育部重点实验室山西太原030051

频率稳定度是评价相干布局囚禁(CPT)原子钟性能的重要指标,而原子气室内部缓冲气体的种类及其气压比是影响CPT原子钟频率稳定度的主要因素。选用Ar与N2为缓冲气体,从理论上对其温度频移特性进行仿真分析,并在不同缓冲气体气压比例的条... 详细信息

频率稳定度是评价相干布局囚禁(CPT)原子钟性能的重要指标,而原子气室内部缓冲气体的种类及其气压比是影响CPT原子钟频率稳定度的主要因素。选用Ar与N2为缓冲气体,从理论上对其温度频移特性进行仿真分析,并在不同缓冲气体气压比例的条件下实验测量了CPT原子钟的温度频移特性。根据理论与实验结果确定了原子气室内部缓冲气体最佳的比例,并给出了与之对应的最小温度频移工作点。研究结果对设计CPT原子钟原子气室内部的缓冲气体气压比及其工作温度具有借鉴作用。

关键词：原子与分子物理原子钟原子气室频率稳定度温度频移

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Research on the Performance of Multi-GNSS Medium Length Baseline RTK with LEO-Augmented

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2020年第5期E103A卷 780-784页

作者： hu, Weisheng Liang, xuwen Hou, huiling Xie, Zhuochen He, Xiaohe Chinese Acad Sci Shanghai Inst Microsyst & Informat Technol Shanghai Peoples R China Chinese Acad Sci Shanghai Engn Ctr Microsatellites Shanghai Peoples R China Univ Chinese Acad Sci Beijing Peoples R China ShanghaiTech Univ Sch Informat Sci & Technol Shanghai Peoples R China

In this letter, we simulate GNSS/LEO measurements and propose a process strategy for LEO-augmented GNSS medium length baseline RTK. Experiments show that, the performance of GNSS medium length baseline RTK can be significantly improved by introducing LEO satellites. The convergence speed of LEO-augmented GPS or BDS float solution maybe better than GPS/BDS combined under the conditions of similar satellite geometry. Besides, the RMS error of fixed solutions are improved to better than 4 cm from sub-decimeter level.

关键词： multi-GNSS LEO-augmented medium length baseline RTK

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Influence of hydrostatic pressure on the corrosion and discharging behavior of Al-Zn-In-Mg-Ti alloy

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JOURNAL OF ALLOYS AND COMPOUNDS 2023年 936卷

作者： hu, Shengbo Yuan, xuwen Liu, Li Liu, Rui Li, Fengguang Liu, Jianyong Guo, Rui Yang, Wei Wang, Fuhui Hubei Univ Automot Technol Sch Mat Sci & Engn Shiyan 442002 Peoples R China Northeastern Univ Shenyang Natl Lab Mat Sci 3-11 Wenhua Rd Shenyang 110819 Peoples R China

The corrosion and discharging behavior of Al-Zn-In-Mg-Ti alloy were studied at a series pressures ranged from 0.1 MPa to 13.0 MPa using weigh loss experiments, electrochemical techniques, and imaging mea-surements et al. Results reveal that the self-corrosion and self-discharging process of Al-Zn-In-Mg-Ti alloy live through the same three stages, which are all accelerated by hydrostatic pressure. The discharging performance of Al-Zn-In-Mg-Ti drops with increasing pressure, which is caused by the acceleration of cathodic process and severer intergranular corrosion. The corresponding cathodic protection design based on Al-Zn-In-Mg-Ti sacrificial anode with the changing pressure has been set up, which follows exponential function.(c) 2022 Elsevier B.V. All rights reserved.

关键词： Sacrificial anode Hydrostatic pressure Intergranular corrosion EIS

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Fabrication and properties of MEMS compatible energetic arrays based on carbon-based copper azide

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APPLIED SURFACE SCIENCE 2022年 577卷 150643-150643页

作者： Liu, xuwen hu, Yan Chen, Bingwen Wei, Hai Su, Jiaxin Yang, Caimin hu, Jiaheng Ye, Yinghua Shen, Ruiqi Nanjing Univ Sci & Technol Sch Chem & Chem Engn Nanjing 210094 Peoples R China Minist Ind & Informat Technol Micronano Energet Devices Key Lab Nanjing 210094 Peoples R China

Copper azide is a promising primary explosive with low toxicity and high energy density. However, due to the extreme electrostatic sensitivity, it does not have many practical applications in the miniaturized pyrotechnics. In this work, we constructed an energetic composite, embedding in oriented carbon nanotubes (CNTs) arrays grown on a silicon substrate, which is compatible with the micmfabrication technique of Micro-Electro-Mechanical Systems (MEMS). Since it has excellent electrical conductivity and mechanical strength, oriented CNTs, as nano-containers of Cu(N-3)(2), can availably reduce the electrostatic sensitivity and bring about the directional output of detonation energy. The oriented CNTs arrays were prepared by magnetron sputtering, anodization and chemical vapor deposition successively. Electrochemical deposition was used to deposit copper nanoparticles in the cavities of CNTs, which were converted into copper azide by subsequent in-situ azide reaction. The electrostatic sensitivity test, thermal performance analysis and laser ignition experiment were conducted on the energetic composite, respectively. The results show that the energetic composite kept safe under an electrostatic stimulation of 3.18 mJ, while original copper azide exploded when subjected to stimulation of 0.05 mJ. The energetic composite opens a new route of introducing hazardous primary explosives into micro-initiators and modern pyrotechnics.

关键词： Composite energetic materials Copper azide Oriented CNTs array Template method Electrochemical deposition Electrostatic safety

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Cation defect engineering in LaCoO3 perovskite as the "Two birds one stone" strategy to enhanced Fenton-like reaction: Regulating Co spin state and optimizing electron transfer ability

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SEPARATION AND PURIFICATION TECHNOLOGY 2024年 337卷

作者： Fang, Zhimo Feng, xuwen Zhou, Zhou Zeng, Zepeng Xia, Yuangu Li, Jihong Liu, Ji hu, Bin Li, Kai Lu, Qiang North China Elect Power Univ Natl Engn Res Ctr New Energy Power Generat Beijing 102206 Peoples R China

The reactive oxygen species (ROS) triggered by peroxymonosulfate (PMS), primarily composed of radicals and nonradicals, can deeply and selectively remove pollutants in complex wastewater. However, the low efficiency of electron transfer and insufficient surface catalytic sites remain the main obstacles to the development of efficient and selective PMS activators. Herein, we constructed ABO(3) perovskite catalysts (LaCoO3) with adjustable La vacancies (V-La) densities through urea introduction. Experiment, characterization, and theoretical calculation jointly revealed that VLa could not only induce electron delocalization in Co site to enhance the Co 3d - O 2p covalency for accelerating ROS (sulfate radicals (SO4 center dot-), singlet oxygen (O-1(2)), and high valent cobalt (Co(IV) = O)) generation, but also trigger the transition of spin-polarization configuration to form Co3+ (t(2g)(5)e(g)(1)) with the intermediate spin state as new active sites for surface-bound PMS* complexes production. The nonradical-dominated and radical-assisted system containing multi-site achieved efficient PMS utilization (95.6 %), excellent decontamination activity (0.753 min(-1)), good mineralization ability (82.7 %), satisfactory acid-base resistance (working pH range 3-11), and environmental robustness for actual water treatment. This study reveals the role of cation vacancy engineering in achieving "Two birds one stone" for PMS activation at the atomic level, which will guide the rational design of Fenton-like catalysts.

关键词： Peroxymonosulfate La vacancies Spin state Delocalization Radicals and nonradicals

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