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Modeling and Analysis of Drift Error from Stator of A MSSG with Double Spherical Envelope Surfaces
Chao-Jun Xin,Yuan-Wen Cai,Yuan Ren,Ya-Hong Fan 대한전기학회 2016 Journal of Electrical Engineering & Technology Vol.11 No.5
For the newly developing magnetically suspended sensitive gyroscope (MSSG) with double spherical envelope surfaces, it is necessary to analyze the causes of drift error to improve sensing accuracy. This paper builds the models of disturbing torques generated by stator assembly and process errors based on the geometric construction and running regularity of the MSSG, and further reveals the generation mechanism of the drift error. Then the drift error from a single stator magnetic pole is calculated quantitatively with the established model, and the key factors producing the drift error are further discussed. It is proposed that the main approaches in reducing the drift error from stator are guaranteeing the rotor envelope surface to be an ideal spherical and improving the controlling precision of rotor displacement. The common problems associated in a gyroscope with a spherical rotor can be effectively resolved by the proposed method. This analysis provides a reference for the structure optimization and error compensation of a MSSG.
Chao-Jun Chen,Jun Teng,Zuo-Hua Li,Qing-Gui Wu,Bei-Chun Lin 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.78 No.3
An AMD control system is usually built based on the original model of a target building. As a result, the fact leads a large calculation workload exists. Therefore, the orders of a structural model should be reduced appropriately. Among various model-reduction methods, a suitable reduced-order model is important to high-rise buildings. Meanwhile, a partial structural information is discarded directly in the model-reduction process, which leads to the accuracy reduction of its controller design. In this paper, an optimal technique is selected through comparing several common model-reduction methods. Then, considering the dynamic characteristics of a high-rise building, an improved balanced truncation (BT) method is proposed for establishing its reduced-order model. The abandoned structural information, including natural frequencies, damping ratios and modal information of the original model, is reconsidered. Based on the improved reduced-order model, a new reduced-order controller is designed by a regional pole-placement method. A high-rise building with an AMD system is regarded as an example, in which the energy distribution, the control effects and the control parameters are used as the indexes to analyze the performance of the improved reduced-order controller. To verify its effectiveness, the proposed methodology is also applied to a four-storey experimental frame. The results demonstrate that the new controller has a stable control performance and a relatively short calculation time, which provides good potential for structural vibration control of high-rise buildings.
( Chao Dong ),( Han Jun Li ),( Shi Chang ),( Hui Jun Liao ),( Zhi Peng Zhang ),( Peng Huang ),( Hui Huan Tang ) 대한간학회 2013 Gut and Liver Vol.7 No.2
Background/Aims: We aimed to investigate the correlation between a disintegrin and metalloprotease with thrombospondin motif 2 (ADAMTS-2) and transforming growth factor-β1 (TGF-β1) in clinical human cirrhotic tissues. Methods: The liver tissues of 24 patients (16 cases with cirrhotic portal hypertension as the cirrhosis group and eight cases with healthy livers as the normal group) were collected. Immunohistochemistry and Western blots were performed to evaluate the protein expression levels of ADAMTS-2 and TGF-β1. Western blots for other key mediators of cirrhotic progression, including SMAD2, SMAD3, TGF-β receptor II (TGFβRII), matrix metalloproteinases 2 (MMP2), and tissue inhibitor of matrix metalloproteinases 2 (TIMP2), were also performed. Results: Cirrhotic tissues showed higher percentages of collagen. The protein expression levels of ADAMTS-2 and TGF-β1 were significantly higher in the cirrhotic group as compared to the matched normal group (p<0.05), and there was a positive correlation between these two proteins (r=0.862, p<0.01). The protein expressions of MMP2, TIMP2, and TGFβRII, as well as the phosphorylated forms of SMAD2 and SMAD3, were significant higher in the cirrhotic group (p<0.01 or p<0.05). Conclusions: These findings suggested that ADAMTS-2 and TGF-β1 may play important roles in the pathogenesis of human cirrhosis; specifically, TGF-β1 may induce the expression of ADAMTS-2 through the TGFβ/SMAD pathway. (Gut Liver 2013;7:213-220)
Chao-bin Wang,Hui Wang,Jun-shuang Zhao,Ze-jun Wu,Hao-dong Liu,Chao-jia Wang,An-rong Li,Dawei Wang,Juntao Hu 대한신경외과학회 2023 Journal of Korean neurosurgical society Vol.66 No.5
Penetrating head injury is a serious open cranial injury. In civilians, it is often caused by non-missile, low velocity flying objects that penetrate the skull through a weak cranial structure, forming intracranial foreign bodies. The intracranial foreign body can be displaced due to its special quality, shape, and location. In this paper, we report a rare case of right-to-left displacement of an airgun lead bullet after transorbital entry into the skull complicated by posttraumatic epilepsy, as a reminder to colleagues that intracranial metal foreign bodies maybe displaced intraoperatively. In addition, we have found that the presence of intracranial metallic foreign bodies may be a factor for the posttraumatic epilepsy, and their timely removal appears to be beneficial for epilepsy control.
Chao-Jun Xin,Yuan-Wen Cai,Yuan Ren,Ya-Hong Fan 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.2
The aim of this paper is to design a centrifugal deformation error compensation method with guaranteed performance that allows angular velocity measurement of the magnetically suspended sensitive gyroscopes (MSSGs). The angular velocity measurement principle and the structure of the MSSG are described, and the analytical model of errors caused by MSSG rotor centrifugal deformation is established. Then, an on-line rotor centrifugal deformation error compensation method based on measurement of rotor spinning speed in real-time has been designed. The common issues caused by centrifugal deformation of spinning rotors can be effectively resolved by the proposed method. Comparative experimental results before and after compensation demonstrate the validity and superiority of the error compensation method.
Synthesis and Antibacterial Activities of New S-glycosides Bearing 1,2,4-Triazole
Chao, Shu-Jun,Geng, Ming-Jiang,Wang, Ying-Ling Korean Chemical Society 2010 대한화학회지 Vol.54 No.6
5-Aryl-3-($\beta$-D-glucopyranosylthio)-1,2,4-triazole 화합물들을 합성하였으며, 합성한 화합물들에 대한 항균활성시험을 수행하였다. Several new 5-aryl-3-($\beta$-D-glucopyranosylthio)-1,2,4-triazoles have been synthesized. The structures of these new compounds were confirmed by $^1H$ NMR, $^{13}C$ NMR and elemental analyses.The antibacterial activities of the compounds were also evaluated.
Wen Jun Gong,Zhigang Tao,Man Chao He,Hui Jun Hou 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.9
As a typical and complex failure type of rock slopes, flexural toppling failure has increasingly received attention, mainly focused on its failure mechanism and introducing a proper numerical method to reproduce the failure phenomena. However, there are few studies related to the supporting mechanism against flexural toppling failure. This study attempted to make a preliminary analysis on the research gap. For this purpose, an anti-dip layered rock slope supported with anchor cables that failed owning to flexural toppling was taken as an example, and the numerical method discontinuous deformation analysis (DDA) was taken as the major analytical tool. Firstly, the rationality of DDA was verified by correctly simulating the failure state of the anti-layered rock slope and the underlying failure mechanism was studied. The results indicated that the lack of the support from slope toe is the crucial factor inducing the flexural toppling failure, which posed a great obstacle to the further excavation of the open-pit mine. Secondly, by introducing the anchor cable support to the slope toe in the DDA model, the interaction mechanism between the anchor cables and the rock slope was investigated. the results indicated that the supporting system of the ordinary anchor cables is very sensitive to the inhomogeneous flexural toppling deformation. The tension values of the anchor cables are very inhomogeneous, and once some of anchor cables beyond their tension limit, the anchor cables failed, which will greatly threaten the safety of the adjacent anchor cables and even the stability of the whole slope. Meanwhile, a novel anchor cable called constant-resistance-large-deformation (CRLD) anchor cable was introduced for a comparative study using DDA. just replacing the anchor cables of the original slope with the CRLD anchor cables, the slope can reach stable state eventually even without the slope toe being enhanced. In addition, the CRLD anchor cables were able to support the slope well against the inhomogeneous deformation, because they can provide high constant resistances and withstand large deformations. This study can provide a deeper insight into the support mechanism for the snit-layered rock slope against flexural toppling failure and introduce a novel supporting method for such slopes.