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基于LSTM阈值法的蒸汽动力辅助系统故障预警研究

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舰船科学技术 2024年第13期46卷 150-157页

作者：梁聚伟李东亮陈焰恺耿江华海军工程大学湖北武汉430033 海军工程大学动力工程学院湖北武汉430033 中国人民解放军91251部队上海201900 海军工程大学兵器工程学院湖北武汉430033

为了提高船舶蒸汽动力辅助系统的运行安全性和可靠性,减少系统故障导致的船舶停航和潜在安全事故,提出一种结合长短期记忆网络(Long Short-Term Memory network,LSTM)和阈值法的故障预警方法。首先,利用LSTM模型处理船舶蒸汽动力辅助系... 详细信息

为了提高船舶蒸汽动力辅助系统的运行安全性和可靠性,减少系统故障导致的船舶停航和潜在安全事故,提出一种结合长短期记忆网络(Long Short-Term Memory network,LSTM)和阈值法的故障预警方法。首先,利用LSTM模型处理船舶蒸汽动力辅助系统的历史运行数据、学习系统的动态行为和潜在故障模式。其次,通过设定阈值法,结合LSTM模型的预测输出,实现对系统状态的实时监控和故障预警。最后,基于MINIS一体化仿真平台开发的蒸汽动力辅助系统模型,以汽轮给水泵转速故障为例,进行故障预警实验,验证方法的有效性。实验结果显示,结合LSTM的预测能力和阈值法的决策效率,提出的预警模型能有效识别并预警汽轮给水泵的转速故障。通过对比实际故障数据,模型在预测准确性和预警及时性方面均表现出色。该方法不仅提高了故障预警的准确性,而且为船舶维护和安全管理提供了有力决策支持,为类似工业系统的故障预警提供了新的研究思路。

关键词：蒸汽动力辅助系统故障预警长短期记忆网络(LSTM) 阈值法

超高效液相色谱-串联质谱测定水源水中176种药品和个人护理用品含量

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食品科学 2024年第4期45卷 307-314页

作者：吴少明刘文菁戴明何孟杭陈言凯王征詹重清欧阳立群福建省产品质量检验研究院国家加工食品质量检验检测中心福建福州350002

基于固相萃取结合超高效液相色谱-串联质谱技术建立同时测定水源水中176种药品和个人护理用品(pharmaceutical and personal care products,PPCPs)含量的方法。将水源水调节至pH 7后,经Cleanert PEP固相萃取柱富集净化,洗脱液采用二甲... 详细信息

基于固相萃取结合超高效液相色谱-串联质谱技术建立同时测定水源水中176种药品和个人护理用品(pharmaceutical and personal care products,PPCPs)含量的方法。将水源水调节至pH 7后,经Cleanert PEP固相萃取柱富集净化,洗脱液采用二甲基亚砜辅助浓缩后,以甲醇-0.1%甲酸水(含0.2 mmol乙酸铵)为流动相,在HSS T3色谱柱(2.1 mm×150 mm,1.8μm)中进行分离,用电喷雾离子源(正负离子切换模式)、多反应监测模式进行测定。方法学验证结果表明,176种PPCPs在5~200 ng/mL范围内线性关系较好,相关系数均高于0.99。176种PPCPs的方法的定量限为0.1 ng/mL。在空白水样中进行3种加标水平(0.1、0.4、1.0 ng/mL)的加标回收实验(n=6),176种化合物的平均回收率在68.0%~126.7%之间,相对标准偏差在1.1%~10.3%之间。综上,本研究所建立的方法简单快速、重现性好、灵敏度高,能够满足水源水中176种PPCPs含量的高通量检测要求。

关键词：固相萃取超高效液相色谱-串联质谱药品和个人护理用品水源水

Enantioselective direct aldol-type reaction of 4-hydroxycoumarin with ethyl trifluoropyruvate catalyzed by modified cinchona alkaloids

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Chinese Science Bulletin 2010年第17期55卷 1732-1734页

作者： CUI HaiLei JIANG Kun LIU yankai Du Wei chen YingChun Key Laboratory of Drug-Targeting and Drug Deliver System of Ministrv of Education Department of Medicinal Chemistry West China School of Pharmacy Siehuan University Chengdu 610041 China

A new enantioselective aldol-type reaction of 4-hydroxycoumarins and ethyl trifluoropyruvate has been developed. In the presence of (DHQD)2PHAL (5 mol%), ethyl trifluoropyruvate could react with various 4-hydroxycoumarins to afford novel 4-hydroxycoumarin derivatives containing a tertiary trifluoromethyl alcohol center in good yields with moderate enantioselectivities.

关键词：对映选择性三氟甲基金鸡纳生物碱反应羟基改性催化乙基

On-chip ultrafast pulse generation based on graphene-silicon hybrid waveguides

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Photonics Research 2021年第9期9卷 1660-1666页

作者： MENG DENG ZICHUN LIAO yankai chen NINGNING YANG XU YAN CHI ZHANG NENGLI DAI YI WANG Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China

On-chip ultrafast mode-locking lasers are basic building blocks for the realization of a chip-based optical frequency *** this paper,an ultrafast saturable absorber made up of a graphene pad on top of a silicon waveguide is applied to implement an ultrafast pulse *** from the small mode area of the graphene/silicon hybrid waveguide,the saturable pulse energy is reduced by two orders of magnitude compared with the fiber.A mode-locked pulse with a duration of 542 fs and a repetition rate of 54.37 MHz is ***–probe measurement shows that the carrier relaxation process of free carrier recombination with atomic-thin graphene/silicon junctions is three orders of magnitude faster than silicon,which plays a fundamental role in pulse *** chip-scale silicon ultrafast laser lays a foundation for a new class of nonlinear devices,in which a combination with multiple functional silicon photonic circuits enables efficient nonlinear interaction at the micrometer scale and less than 1 W of power consumption.

关键词： pulse waveguide absorber

Study and Analysis of Typical Mechanical Structure of Desktop 3D Printer Based on FDM Technology

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Study and Analysis of Typical Mechanical Structure of Deskto...

Residential energy transition and chronic respiratory diseases

2021中国铸造活动周

作者： Xiao GE Tingchun SHI yankai chen Xiuyan YUE Departments of Automation University of Hangzhou Departments of Mechanical Engineering University of Hangzhou Departments of Library University of Hangzhou

Additive manufacturing is a kind of rapid manufacturing that aims to complete the manufacture of prototypes or parts of products based on discrete *** deposition modeling(FDM) technology,as one of the most widely used types of 3 D printing,has incomparable application prospect in many fields concerning medical,aerospace,automotive,construction,arts and *** the trend to rapidly create highly accurate devices that are in various complex shapes,FDM technology has become a hot spot of current *** view of the most widely used type of FDM technology in the field of 3 D printing,this article expounds the working principle,advantages and application fields of FDM *** common mechanical structures of FDM desktop 3 D printers are compared and analyzed,such as the rectangular box structure,rectangular bar structure,linear arm structure and parallel arm *** characteristics of various structures,transmission principles,and research progress are summarized through the selection of typical structural models,and the common features and existing common problems of FDM desktop 3 D printer structures are contrastively analyzed through table ***,the corresponding improvement methods are ***,the prospects of future development and innovation of the FDM desktop 3 D printer are analyzed.

关键词： 3D printing Additive manufacturing Mechanical structure Transmission principle Printing accuracy

来源： cnki会议评论

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The Innovation 2024年第3期5卷 33-43页

作者： Hongcheng Wei Qiurun Yu Danrong chen Mingzhi Zhang Quanquan Guan Bo Hang Antoine M.Snijders Adrian Covaci yankai Xia State Key Laboratory of Reproductive Medicine and Offspring Health Center for Global HealthSchool of Public HealthNanjing Medical UniversityNanjing 211166China Key Laboratory of Modern Toxicology of Ministry of Education School of Public HealthNanjing Medical UniversityNanjing 211166China The Affiliated Wuxi People’s Hospital of Nanjing Medical University Wuxi People’s HospitalWuxi Medical CenterNanjing Medical UniversityWuxi 214023China Biological Systems and Engineering Division Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA Toxicological Centre University of Antwerp2610 WilrijkBelgium

Obtaining clean energy is of prime importance for planetary health and sustainable *** aimed to assess the association between residential energy transition and the risk of chronic respiratory *** data from the Global Health Observatory and Global Burden of Diseases,Injuries,and Risk Factors Study,we delineated the spatial distribution and temporal trends of the population using clean fuels for cooking at a global *** the China Health and Retirement Longitudinal Study,we performed rigorous and well-structured multistage analyses incorporating both cross-sectional and prospective data analyses to examine the associations between solid fuel use,residential energy transition,duration of solid fuel use,and the risk of chronic respiratory *** great progress,huge disparities in access to clean energy persist *** energy transition was associated with a lower risk of chronic respiratory *** the period of 2011–2013,compared with persistent solid fuel users,both participants who switched from solid to clean fuels(adjusted risk ratio[RR]0.78,95%confidence interval[CI]0.62–0.98)and persistent clean fuel users(adjusted RR 0.71,95%CI 0.57–0.89)had significantly lower risk of chronic respiratory diseases(p<0.001 for trend).Consistent associations were observed in the period of 2011–2015 and 2011–*** energy transition from solid to clean fuels could reduce the risk of chronic respiratory *** is a valuable lesson for policy-makers and the general public to accelerate energy switching to alleviate the burden of chronic respiratory diseases and achieve health benefits,particularly in low-and middle-income countries.

关键词： cooking income globally

General radical difluoromethylation using difluoroacetic anhydride via photoredox catalysis

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Science China Chemistry 2024年第8期67卷 2637-2646页

作者： Meng He yankai Yang Heng Zhang Zhipeng Guan Zhi-Bing Dong Hong Yi Aiwen Lei School of Chemistry and Environmental Engineering Wuhan Institute of TechnologyWuhan 430205China College of Chemistry and Molecular Sciences and Institute for Advanced Studies(IAS) Wuhan UniversityWuhan 430072China

CF_(2)H-containing molecules play pivotal roles in diverse fields from medicinal chemistry to materials science. However, the application of existing CF_(2)H reagents as a source of CF_(2)H radical is limited by their reactivity and preparation. Herein, we develop a simple and general visible-light-catalyzed radical difluoromethylation reaction of alkenes, dienes, and heteroaromatics using commercially available, easy-to-handle, and low-cost difluoroacetic anhydride as the CF_(2)H reagent. This scalable protocol enables the convenient synthesis of a range of CF_(2)H-containing compounds under mild conditions, exhibiting a broad substrate scope and functional group tolerance. Potential applications are further demonstrated by gram-scale synthesis, sunlight experiments, derivatization experiments as well as the synthesis of bioactive molecules.

关键词： radical difluoromethylation alkenes/dienes/heteroaromatics difluoroacetic anhydride photoredox

Qualitative and quantitative analysis of Brønsted and Lewis acid sites in zeolites:A combined probe-assisted ^(1)H MAS NMR and NH_(3)-TPD investigation

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Chinese Journal of Structural Chemistry 2024年第4期43卷 24-30页

作者： Runze Liu yankai Bian Weili Dai School of Materials Science and Engineering&National Institute for Advanced Materials Nankai UniversityTianjin300350PR China

Zeolite is one of the most important heterogeneous catalysts in acid catalytic *** that the catalytic behaviors of zeolites are mostly related to their acidic characteristics,extensive attention has been attracted to the measurements of acid type,strength and concentration in *** techniques including Fourier-transform infrared(FTIR)spectroscopy,probe-assisted^(1)H,^(13)C and^(31)P magic angle spinning nuclear magnetic resonance spectroscopy(MAS NMR)as well as temperature programmed desorption of ammonia(NH_(3)-TPD)have been developed for determining the acid ***,a single approach is defective to characterize the acid sites ***,combining the probe-assisted(e.g.,NH_(3)and CD_(3)CN)^(1)H MAS NMR and NH_(3)-TPD,the acid sites in different zeolites including the acid type,density and strength were *** commonly utilized NH_(3)-TPD to determine the acid strength of zeolite samples with different topologies should be rigorously considered owing to zeolite confinement *** the desorption temperature of NH_(3)probe molecules,the acid type(Le.,Brønsted acid sites(BAS)and Lewis acid sites(LAS))and the corresponding density could be determined by NH_(3)probe-assisted^(1)H MAS NMR spectroscopy,while the acid strength could be investigated via CD_(3)CN probe-assisted^(1)H MAS NMR spectroscopy.

关键词： ^(1)H MAS NMR NH_(3)-TPD BAS LAS Zeolites

Synergistically enhanced dielectric, insulating and thermally conductive performances of sandwich PMMA based dielectric films

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Progress in Natural Science:Materials International 2024年第3期34卷 591-597页

作者： Dongmei Zhang Yufan Li Yuchao Li Zhonggui Sun Hanxue Zhu Lujia Yang Yanhu Zhan yankai Li Shi Wang Jun-Wei Zha School of Mathematical Sciences Liaocheng University School of Materials Science and Engineering Liaocheng University State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM) Nanjing University of Posts & Telecommunications School of Chemistry and Biological Engineering University of Science and Technology Beijing

A tri-layered(B-G-B) dielectric films were simply prepared by alternatively spin-coating boron nitride/polymethylmethacrylate(BN/PMMA, B) and graphene nanosheets(GNS/PMMA, G) compound solutions. The structure, morphology, thermal conductivity, and particularly the dielectric and relaxation behaviors were systematically studied. Results showed that a good exfoliation and dispersion of BN and GNS can be simply achieved through intensive mechanical compounding with PMMA in the internal mixer. The dielectric constant and breakdown strength of the obtained 1-3-1(B-G-B) sandwich composite film reached 4.3(@1 kHz) and 458.6kV/mm, being 119 % and 113 % higher than that of pure PMMA, respectively. Furthermore, the overall thermal conductivity of sandwich 1-3-1 composite increased by 112 % due to the addition of thermally conductive BN and GNS. The sandwich design strategy provided an effective way of achieving good permittivity, high insulation, and improved thermal conductivity simultaneously, showing potential applications in the miniaturization and integration of electronic devices.

关键词： Breakdown strength Composites Dielectric constant Sandwich structure Thermal conductivity