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      • Multiple damage detection of maglev rail joints using time-frequency spectrogram and convolutional neural network

        Yi-Qing Ni,Su-Mei Wang,Gao-Feng Jiang,Yang Lu,Guobin Lin,Hong-Liang Pan,Junqi Xu,Shuo Hao 국제구조공학회 2022 Smart Structures and Systems, An International Jou Vol.29 No.4

        Maglev rail joints are vital components serving as connections between the adjacent F-type rail sections in maglev guideway. Damage to maglev rail joints such as bolt looseness may result in rough suspension gap fluctuation, failure of suspension control, and even sudden clash between the electromagnets and F-type rail. The condition monitoring of maglev rail joints is therefore highly desirable to maintain safe operation of maglev. In this connection, an online damage detection approach based on three-dimensional (3D) convolutional neural network (CNN) and time-frequency characterization is developed for simultaneous detection of multiple damage of maglev rail joints in this paper. The training and testing data used for condition evaluation of maglev rail joints consist of two months of acceleration recordings, which were acquired in-situ from different rail joints by an integrated online monitoring system during a maglev train running on a test line. Short-time Fourier transform (STFT) method is applied to transform the raw monitoring data into time-frequency spectrograms (TFS). Three CNN architectures, i.e., small-sized CNN (S-CNN), middle-sized CNN (M-CNN), and large-sized CNN (L-CNN), are configured for trial calculation and the M-CNN model with excellent prediction accuracy and high computational efficiency is finally optioned for multiple damage detection of maglev rail joints. Results show that the rail joints in three different conditions (bolt-loosenesscaused rail step, misalignment-caused lateral dislocation, and normal condition) are successfully identified by the proposed approach, even when using data collected from rail joints from which no data were used in the CNN training. The capability of the proposed method is further examined by using the data collected after the loosed bolts have been replaced. In addition, by comparison with the results of CNN using frequency spectrum and traditional neural network using TFS, the proposed TFSCNN framework is proven more accurate and robust for multiple damage detection of maglev rail joints.

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        Superhydrophobic Ag–Cu Composite Metal Film as Surface-Enhanced Raman Scattering Substrate

        Jianchao Wang,Hongsheng Luo,Xuliang Song,Xihong Zu,Jie Zhang,Yuxin Gu,Guobin Yi 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.7

        In this paper, a superhydrophobic Ag–Cu composite metal film was fabricated as surface-enhanced Raman scattering substrate. Ag–Cu composite metal film was prepared from galvanic displacement on commercial copper foil. The prepared silver films were modified by PFDT to create a stable superhydrophobic SERS platform. Superhydrophobic substrates were characterized by a variety of characterization methods, including scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-Vis, XPS and Raman spectra. The superhydrophobic substrate could enrich probing molecules with the volatilization of solvent. Mathematical model was presented and applied to investigate concentration factor of hydrophobic substrate. The measurements were in good agreement with the calculation results. The superhydrophobic Ag–Cu composite metal film can reduce the detection limits and provide a new way to prepare efficient SERS substrates for ultra-low concentration detection.

      • Dietary and Genetic Obesity Promote Liver Inflammation and Tumorigenesis by Enhancing IL-6 and TNF Expression

        Park, Eek Joong,Lee, Jun Hee,Yu, Guann-Yi,He, Guobin,Ali, Syed Raza,Holzer, Ryan G.,Ö,sterreicher, Christoph H.,Takahashi, Hiroyuki,Karin, Michael Elsevier 2010 Cell Vol.140 No.2

        <P><B>Summary</B></P><P>Epidemiological studies indicate that overweight and obesity are associated with increased cancer risk. To study how obesity augments cancer risk and development, we focused on hepatocellular carcinoma (HCC), the common form of liver cancer whose occurrence and progression are the most strongly affected by obesity among all cancers. We now demonstrate that either dietary or genetic obesity is a potent bona fide liver tumor promoter in mice. Obesity-promoted HCC development was dependent on enhanced production of the tumor-promoting cytokines IL-6 and TNF, which cause hepatic inflammation and activation of the oncogenic transcription factor STAT3. The chronic inflammatory response caused by obesity and enhanced production of IL-6 and TNF may also increase the risk of other cancers.</P> <P><B>Graphical Abstract</B></P><P><ce:figure></ce:figure></P><P><B>Highlights</B></P><P>► Obesity promotes hepatocellular carcinoma (HCC) in mice via TNF and IL-6 cytokines ► TNF and IL-6 promote liver fat accumulation and fat-induced liver inflammation ► Loss of TNF receptor 1 prevents fat-induced liver injury and HCC development ► Ablation of the IL-6 gene also prevents obesity-promoted HCC development</P>

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        Dual-Responsive Cross-Linked Micelles from Amphiphilic Four-Arm Star Copolymers with Different Block Ratios for Triggering DOX Release

        Yunwei Huang,Yanzhe Li,Zilun Tang,Qiuping Su,Tingting Liao,Yuxin Gu,Xiaofeng Lin,Xihong Zu,Wenjing Lin,Guobin Yi 한국고분자학회 2020 Macromolecular Research Vol.28 No.8

        The four-arm star copolymers poly(methacrylic acid)-poly(2-hydroxyethyl methacrylate-disulfide~)-poly(poly(ethylene glycol) methyl ether methacrylate) (4AS-PMAAx-(PHEMA-SS~)y-PPEGMAz) with four different block ratios were synthesized and could self-assembled into cross-linked polymer micelles for the exploration of the structure-property relationship. The cross-linked polymer micelles in aqueous solution had low critical micelle concentration (CMC) values (1.9-4.6 mg/L), which exhibited better stability than non-cross-linked micelles. The CMC value decreased with the increase of the length of inner PMAA core and hydrophobic PHEMA cross-linked middle layer. The blank and doxorubicin (DOX)- loaded micelles with different block ratios were prepared by dialysis with the particle sizes of 120-240 nm. The longer inner PMAA core and cross-linked middle layer enhanced the drug loading content (DLC) results and led to relatively bigger particle sizes of polymer micelles. The in vitro DOX release data revealed that DOX-loaded micelles had low DOX cumulative release percentages of 18-37% after 110 h at pH 7.4, but up to 83-90% when introducing reductant GSH at pH 5.0. The 4AS-PMAA21.2-(PHEMASS~) 13.1-PPEGMA5.1 micelles with the longest PMAA core had the largest cumulative release of 90.1%. The DOX release process and mechanism of the micelles at different conditions fitted well with the semi-empirical equation. Overall, the results demonstrated that the block ratios and pH/redox-responsiveness of these four-arm star copolymers could be well-controlled and their self-assembled cross-linked micelles as anticancer drug carrier system could be improved by optimizing the different ratios.

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