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37th European Frequency and Time Forum, EFTF 2024

作者： Li, Chao sun, Fuyu Hu, xuwen Liu, Jie Li, Xiaofeng Zhang, Shougang National Time Service Center Chinese Academy of Sciences Xi'an China Chinese Academy of Sciences Key Laboratory of Time Reference and Applications Xi'an China

ISBN: (纸本)9798350354270

Compact optically pumped cesium beam clocks have become a focus in cesium clock research due to their high atomic utilization and excellent short-term frequency stability. However, stray light noise, one of the main noise sources, limits the stability improvement. In this paper, we present a compact optically pumped cesium clock that uses differential detection to reduce the impact of stray light on clock performance. It incorporates an additional fluorescence collector to capture stray light during detection and subtract it from the clock transition signal, effectively reducing stray light level. Consequently, this scheme significantly enhances the signal-to-noise ratio, improving the short-term frequency stability of the compact optically pumped cesium clock. © 2024 IEEE.

关键词： Frequency stability

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An Improved Design of Atomic-Beam Fluorescence Collector 37

An Improved Design of Atomic-Beam Fluorescence Collector

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37th European Frequency and Time Forum, EFTF 2024

作者： Hu, xuwen sun, Fuyu Li, Chao Liu, Jie Li, Xiaofeng Zhang, Shougang National Time Service Center Chinese Academy of Sciences Xi'an China Chinese Academy of Sciences Key Laboratory of Time Reference and Applications Xi'an China

ISBN: (纸本)9798350354270

Efficient fluorescence detection is crucial in the field of precision spectral analysis. This paper presents an improved design of an atomic-beam fluorescence collector that utilizes the convergence characteristics of ellipsoidal surfaces and the reflection characteristics of spherical surfaces. It calculates the parameter relationship for achieving full-angle fluorescence collection. The study fine-tunes the structural parameters and simulates the fluorescence collection efficiency and losses under different conditions when emitting from a non-ideal point light source. The improved fluorescence collector captures photons with nearly 4n solid angle coverage, allowing photons to be reflected at most twice before reaching the photo detector, thereby increasing collection efficiency. This improved collector can be used in various fields for detecting weak fluorescence signals. © 2024 IEEE.

关键词： Fluorescence microscopy

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Steroidal saponins from the roots of Polygonatum odoratum and their inhibitory effects against pancreatic lipase

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PHYTOCHEMISTRY LETTERS 2023年 53卷 202-210页

作者： Zhao, Dexin Yan, Jianghong Shi, Xiaolei sun, Zhiheng Xie, Huili Wang, Bingzi Jin, Yongri Li, xuwen Jilin Univ Coll Chem Changchun 130012 Peoples R China Jilin Prov Acad Tradit Chinese Med Clin Hosp 1 Changchun 130021 Peoples R China Jilin Univ Coll Food Sci & Engn Changchun 130062 Peoples R China

Twenty steroidal saponins were isolated from the water extract of fresh fibrous roots of Polygonatum odoratum (Mill.) Druce, of which seven were new compounds (1-7) along with thirteen known compounds (8-20). Their chemical structures were elucidated by extensive spectroscopic and chemical techniques. All isolated compounds were evaluated for porcine pancreatic lipase inhibitory activity. Compounds 9 and 10 showed inhibitory effects with IC50 values of 201.90 +/- 0.036 mu M and 151.20 +/- 0.058 mu M (positive control orlistat;2.82 +/- 0.060 mu M).

关键词： Polygonatum odoratum (Mill ) Druce Steroidal saponins Pancreatic lipase inhibitors

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Steroidal saponins from Allium chinense and their inhibitory effects on pancreatic lipase

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PHYTOCHEMISTRY LETTERS 2023年第1期55卷 22-29页

作者： Xie, Huili Shi, Xiaolei Wang, Bingzi Zhao, Dexin sun, Zhiheng Chen, Yifu Feng, Yuezhu Jin, Yongri Li, xuwen Jilin Univ Coll Chem Changchun 130012 Peoples R China Jilin Univ Coll Food Sci & Engn Changchun 130062 Peoples R China

Allium chinense *** is an important medicinal and edible homologous plant and indigenous to China and grown in other countries. Phytochemical studies have shown that it is rich in biologically active natural products. Herein, five new and twelve known steroidal saponins were isolated from the bulbs of Allium chinense ***. These compounds were structurally determined by analysis of their NMR, IR and HR-ESI-MS data. All isolates were evaluated for inhibition of porcine pancreatic lipase activity. Compounds 4, 7 and 10 exhibited potent inhibition of porcine pancreatic lipase. The relationship between structure and activity of these compounds is also investigated in this paper.

关键词： Allium chinense Steroidal saponins Extraction and isolation Structure identification Lipase inhibitory activity

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Surface interaction mechanisms of air bubbles, asphaltenes and oil drops in aqueous solutions with implications for interfacial engineering processes

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JOURNAL OF COLLOID AND INTERFACE SCIENCE 2023年第1期647卷 264-276页

作者： Yang, Diling Zhao, Ziqian Gong, Lu sun, Yongxiang Peng, xuwen Peng, Qiongyao Wang, Tao Liu, Qi Zhang, Hao Zeng, Hongbo Univ Alberta Dept Chem & Mat Engn Edmonton AB T6G 1H9 Canada

Hypothesis: Surface interactions of bubbles and oil with interface-active species like asphaltenes influence many interfacial phenomena in various engineering processes. It holds both fundamental and practical significance to quantitatively characterize these ***: The surface forces of air bubbles, asphaltenes and asphaltenes-toluene droplets in various aqueous solutions have been quantified using an integrated thin film drainage apparatus and an atomic force microscope coupled with bubble probe. The effects of asphaltenes concentration, pH, salinity, Ca2+ ions and surfactants have been ***: Hydrophobic interaction drives attachment of bubbles and asphaltenes surfaces or oil droplets under high salinity condition. Increasing asphaltenes concentration in oil droplets enhances their hydrophobic attraction with bubbles due to strengthened asphaltenes adsorption and aggregation at oil-water interface. Increasing pH weakens the hydrophobic interaction as oil surfaces become more negatively charged and less hydrophobic. Under low salinity condition, strong electrical double layer and van der Waals repulsion inhibits the bubble-oil droplet contact. Introducing Ca2+ ions and surfactants leads to strong steric repulsion, preventing bubble-oil contact. This research has advanced our mechanistic understanding of how bubbles and oil droplets interact in aqueous systems and offers useful insights to modulate such interactions in oil production, water treatment and other interfacial processes.

关键词： Surface interactions Bubbles Oil droplets Flotation Interfacial Forces Emulsion

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Synergistic Catalysis of Binary RuP Nanoclusters on Nitrogen-Functionalized Hollow Mesoporous Carbon in Hydrogen Production from the Hydrolysis of Ammonia Borane

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JOURNAL OF PHYSICAL CHEMISTRY LETTERS 2021年第1期12卷 696-703页

作者： Lv, Hao Wei, Ren Guo, xuwen sun, Lizhi Liu, Ben Sichuan Univ Coll Chem Chengdu 610064 Peoples R China Nanjing Normal Univ Jiangsu Collaborat Innovat Ctr Biomed Funct Mat Sch Chem & Mat Sci Jiangsu Key Lab New Power Batteries Nanjing 210023 Peoples R China

Exploring highly efficient nanocatalysts for hydrogen (H-2) production from catalytic hydrolysis of ammonia borane (AB) under ambient conditions and further unveiling their catalytic mechanism are of critical importance for renewable energy conversion technologies but remain big challenges. Herein, ultrafine binary RuP alloy nanoclusters homogeneously encapsulated onto nitrogen-functionalized hollow mesoporous carbon supports (RuP@NHMCs) are reported as a high-performance platinum (Pt)-free nanocatalyst for catalytic hydrolysis of AB at room temperature. Remarkable catalytic activity with a very high turnover frequency of 1774 mol(H2) mol(Ru)(-1) min(-1) and a low activation energy of 36.3 kJ mol(-1) is observed based on compositional and structural synergies of RuP@NHMCs. Results of control experiments and catalytic kinetics studies reveal that the rate-determining step of catalytic hydrolysis of AB is the oxidation cleavage of a covalently stable H-OH bond, while RuP@NHMCs result in multiple electronic, functional, size, and support effects that kinetically accelerate the cleavage of attacked H-OH. Furthermore, RuP@NHMCs exhibit a good catalytic activity with a high yield of >99% for tandem hydrogenation of nitroarenes coupled with the hydrolysis of AB. We strongly believe that the catalyst design principle reported here could provide a new opportunity for synthesizing other Pt-free high-performance nanocatalysts.

关键词： Catalysts Catalytic activity Nanoclusters Hydrolysis Nanocatalysts

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A synergistic water-saving strategy combining stage-specific irrigation and application of exogenous thiamine enhances drought resistance of Xinjiang cotton

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PLANT AND SOIL 2025年 1-14页

作者： Zhao, Fuxiang Xia, Linjie sun, Simin Li, Hang Rong, Yuxuan Wang, Yuxin Wang, xuwen Kong, Xianhui Zhu, Longfu Zhang, Xianlong Yu, Yu Yang, Xiyan Xinjiang Acad Agr & Reclamat Sci Cotton Inst Shihezi 832000 Xinjiang Peoples R China Huazhong Agr Univ Natl Key Lab Crop Genet Improvement Wuhan 430070 Hubei Peoples R China Hubei Hongshan Lab Wuhan Peoples R China

Background and aimsXinjiang is the largest cotton planting area in China. However, the perennial water shortage in Xinjiang restricts the development of the cotton industry, making drought one of the important limiting factors. The aim of this study was to evaluate the effectiveness of water-saving scheme and thiamine (Thi) application on alleviating the adverse effects of drought stress on the growth and development of *** this study, five Xinjiang-released cotton varieties (Jinken1775, Jinken1565, Huamian702, Zhongmian979, and Jinfeng2) were selected as the research object, and Xinluzao8 served as the drought-sensitive control. Comprehensive drought resistance index (D) of the drought resistance coefficient (DRC) of four yield and four quality traits were used to evaluate the drought resistant ability of the six cotton varieties under different water conditions and Thi spraying *** stage-specific irrigation strategy (60% during vegetative vs. 90% during the flowering and boll stage) concurrently maintained higher drought resistance across cultivars, with Jinken1565 exhibited the highest drought resistance. This scheme reduced irrigation by 26% while sustaining fiber quality. Exogenous 50 mM Thi further enhanced drought tolerance, reducing transpiration rate by 33% and blade damage by 55%. These results demonstrate that stage-specific water management optimizes drought adaptation in cotton cultivation under drought *** study suggests that a 26% water-saving scheme was proposed for most drought-resistant varieties planted in Xinjiang, and an appropriate scheme to achieve stable yield by Thi application during the early drought condition was proposed for varieties with low drought resistant ability.

关键词： Cotton Drought resistance Comprehensive drought resistance index Thiamine Water saving scheme

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A Curved Four-Conductor Assembly with Larger Uniform Region

A Curved Four-Conductor Assembly with Larger Uniform Region

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2023 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium, EFTF/IFCS 2023

作者： Li, Chao Hu, xuwen sun, Fuyu Liu, Jie Li, Xiaofeng Zhang, Shougang National Time Service Center Chinese Academy of Sciences Xi'an China University of Chinese Academy of Sciences Beijing China

ISBN: (纸本)9798350311426

Most atomic physics setups require a uniform static magnetic field to define a quantization axis. The straight four-conductor assembly has been proven to be a useful structure for producing such a uniform static magnetic field. Here, we present an improved four-conductor assembly, where each conductor consists of one straight section and two curved sections. This hybrid structure arrangement offers more degrees of freedom than the conventional straight four-conductor assembly, enabling a larger uniform field region and better field spatial uniformity. The modified magnetic field generation structure can be used in many fields of atomic precision spectroscopy. © 2023 IEEE.

关键词： curved section four-conductor modified four-conductor static magnetic field uniformity

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aMAP Score as a Predictor for Long-Term Outcomes in Patients with HBV-Related Acute-on-Chronic Liver Failure

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INTERNATIONAL JOURNAL OF GENERAL MEDICINE 2022年 15卷 407-415页

作者： sun, Yunqing Li, Zhuohong Liao, Guichan Xia, Muye Xu, xuwen Cai, Shaohang Peng, Jie Southern Med Univ Nanfang Hosp Dept Infect Dis Guangzhou Guangdong Peoples R China

Background and Aim: The long-term outcomes of patients with hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) remain not well known. This study aimed to investigate whether aMAP score can predict re-hospitalization, hepatocellular carcinoma (HCC) occurrence and long-term mortality in patients with HBV-ACLF. Methods: A total of 82 patients diagnosed with HBV-ACLF and survived over 6 months were enrolled. The median follow-up period was 105 (75.9, 134.1) months. The Cox proportional hazards or logistic regression analysis was used to determine independent risk factors. Cumulative incidence of HCC and survival rate were evaluated using Kaplan-Meier analysis. Results: Multivariate analysis identified that the aMAP risk score was an independent predictor of re-hospitalization (odds ratio [OR] = 1.112, 95% confidence interval [CI]: 1.021-1.211, p = 0.015), hepatocellular carcinoma occurrence (hazards ratio [HR] = 2.277, 95% CI: 1.014-5.114, p = 0.046) and mortality (HR = 1.366, 95% CI: 1.040-1.794, p = 0.025). High-risk aMAP scores were associated with higher risk of HCC occurrence and mortality. Conclusion: A higher aMAP score was an independent risk predictor of re-hospitalization, HCC occurrence and mortality, respectively, in HBV-ACLF patients who survived over 6 months, which can be applicable for early risk stratification and clinical decision.

关键词： acute-on-chronic liver failure chronic hepatitis B virus infection re-hospitalization hepatocellular carcinoma mortality prognosis

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Gas hydrate in-situ formation and dissociation in clayey-silt sediments: An investigation by low-field NMR

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ENERGY EXPLORATION & EXPLOITATION 2021年第1期39卷 256-272页

作者： sun, Xiaoxiao Qin, xuwen Lu, Hongfeng Wang, Jingli Xu, Jianchun Ning, Zijie China Geol Survey Guangzhou Marine Geol Survey Guangzhou Peoples R China China Geol Survey Gas Hydrate Engn Technol Ctr Guangzhou Peoples R China China Univ Geosci Beijing Sch Energy Resources Beijing Peoples R China China Univ Petr East China Sch Petr Engn Qingdao Peoples R China

The hydrate reservoir in the Shenhu Area of the South China Sea is a typical clayey-silt porous media with high clay mineral content and poor cementation, in which gas hydrate formation and dissociation characteristics are unclear. In this study, the CO2 hydrate saturation, growth rate, and permeability were studied in sandstone, artificial samples, and clayey-silt sediments using a custom-built measurement apparatus based on the low-field NMR technique. Results show that the T-2 spectra amplitudes decrease with the hydrate formation and increase with the dissociation process. For the artificial samples and Shenhu sediments, the CO2 hydrate occupies larger pores first and the homogeneity of the sandstone pores becomes poor. Meanwhile, compared with the clayey-silt sediments, CO2 hydrate is easier to form and with higher hydrate saturation for the sandstone and artificial samples. In hydrate dissociation process, there exists a protection mechanism, i.e. the dissociation near the center of hydrates grain is suppressed when gas pressure drops suddenly and quickly. For permeability of those samples, it decreased with hydrate forms, and increases with hydrate dissociation. Meanwhile, with the same hydrate saturation, permeability is higher in hydrate formation than in dissociation.

关键词： Gas hydrate clayey-silt sediments NMR formation and dissociation permeability

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