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Yan Hua Wang,Jing Lv,Yan Feng,Bo Wen Dai,Cheng Wang,Jing Wu,Zi Yan Chen 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.28 No.2
Substructure pseudo-dynamic hybrid simulation (SPDHS) is an advanced structural seismic testing method which combines physical experiment and numerical simulation. Generally, the key components which display nonlinearity first are taken as experimental substructures for actual test, and the remaining parts are modeled in simulation. Model updating techniques can be effectively applied to enhance the model precision of nonlinear numerical elements. Specifically, the constitutive model of the experimental substructure is identified online by the instantaneously-measured data, and the corresponding numerical elements with similar hysteretic behaviors are updated synchronously. Artificial neural network (ANN) can recognize the system which cannot be represented by definite numerical model, and thus avoids the structural response distortion caused by the inherent numerical model defects. In this study, a framework for online model updating in SPDHS with ANN method is expanded to implement actual test validation. Moreover, the effectiveness of ANN method is demonstrated by practical tests of a two-story frame model with bending dampers. Additionally, the unscented Kalman filter technique and offline ANN identification approach are both examined in the test validation. The experimental results show that, under the identical loading history, the online ANN method can significantly reduce the model errors and improve the accuracy of SPDHS.
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Rock mechanics and wellbore stability in Dongfang 1-1 Gas Field in South China Sea
Yan, Chuanliang,Deng, Jingen,Cheng, Yuanfang,Yan, Xinjiang,Yuan, Junliang,Deng, Fucheng Techno-Press 2017 Geomechanics & engineering Vol.12 No.3
Thermal effect has great influence on wellbore stability in Dongfang 1-1 (DF 1-1) gas field, a reservoir with high-temperature and high-pressure. In order to analyze the wellbore stability in DF1-1 gas field, the variation of temperature field after drilling was analyzed. In addition, the effect of temperature changing on formation strength and the thermal expansion coefficients of formation were tested. On this basis, a wellbore stability model considering thermal effect was developed and the thermal effect on fracture pressure and collapse pressure was analyzed. One of the main challenges in this gas field is the decreasing temperature of the wellbore will reduce fracture pressure substantially, resulting in the drilling fluid leakage. If the drilling fluid density was reduced, kick or blowout may happen. Therefore, the key of safe drilling in DF1-1 gas field is to predict the fracture pressure accurately.
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A Study of English Morpheme Acquisition Order by Chinese and Korean EFL Learners
Yan Cheng,이보림 대한언어학회 2020 언어학 Vol.28 No.1
The purpose of this study is to evaluate the two contrasting claims for the order of inflectional morpheme acquisition in English as L2: the natural order hypothesis and the hypothesis claiming L1 effects as a fundamental factor. This study also investigates two additional factors that may influence the acquisition of L2 English morphemes: the learner’s English proficiency level and the data elicitation method. For this goal, it involves 38 Korean and 38 Mandarin Chinese learners of English in college, each group of which is in turn divided into two sub-groups according to their English proficiency level. The accuracy scores for six English inflectional morphemes are obtained from two tasks, a freewriting task through journal entries and a fill-in-the-blank type test. Then the results are compared according to the various factors using Spearman’s rank-order correlations based on TLU (target-like use) scores. The results of this study indicate that different L1 groups of the same proficiency level show different acquisition orders, neither of which supports the natural order hypothesis. The data elicitation method and English proficiency, however, do not seem to significantly affect the order of English morphemes. Based on these results, this study concludes that L1 plays a major role in English inflectional morpheme acquisition by EFL learners. It is also noted that input frequency and the amount of classroom instruction can be other important factors affecting English morpheme acquisition, suggesting the need to increase the inputs of low-ranked but important morphemes in the classroom.
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Applicability Analysis of Microseismic Technology in Tunnel Water Inrush Monitoring
Yan-hao Chen,Shuai Cheng,Li-Ping Li,Jun-yan Yang,Hong-liang Liu,Wen-feng Tu 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.7
Water inrush disaster is one of the most serious geological disasters in tunnel construction. There are still some problems in the existing researches, such as the activity information of surrounding rock is difficult to obtain, the mechanism of water inrush disaster is unclear, the correlation between water inrush disaster and microseismic (MS) information is missing, which have caused the water inrush disaster to be passively controlled. Combining with the practical experience of tunnel engineering, the application problems of MS technology in tunnel engineering is summarized, which provides ideas for monitoring of surrounding rock activity. The formation mechanism of water inrush disaster caused by rock mass fracturing and filling medium instability has been revealed. The MS characteristics of the water inrush channel in different water inrush disasters have also been revealed. The MS response characteristics of water inrush and rockburst disasters are compared, which provides guidance for the improvement of MS monitoring technology and the analysis of effective MS information. The compression failure test of limestone under saturated and natural conditions is carried out. The results show that the presence of water weakens the ability of rock to store energy. The acoustic emission (AE) phenomenon is weaker in the process of saturated limestone failure, which increases the difficulty of AE monitoring. The number of AE events of natural limestone and saturated limestone shows a slow increase to a sudden increase in the process stress loading, which can be regarded as an important precursor of rock failure.
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Bicluster and Pathway Enrichment Analysis of HCV-induced Cirrhosis and Hepatocellular Carcinoma
Cheng, Peng,Cheng, You,Su, Mei X.,Li, Dong,Zhao, Guo Z.,Gao, Hui,Li, Yan,Zhu, Jie Y.,Li, Hua,Zhang, Tao Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.8
Background: Hepatocellular carcinoma (HCC) is the sixth most common cancer worldwide and the most common form of liver cancer. However, while it is associated frequently with hepatitis C virus (HCV) there is only an elementary understanding of its molecular pathogenesis. Methods: To gain insight into the molecular mechanisms of HCV-induced hepatocarcinogenesis, we performed microarray analysis on 75 surgical liver samples from 48 HCV-infected patients. Results: There were 395 differentially expressed geness between cirrhotic samples and HCC samples. Of these, 125 genes were up-regulated and 270 genes were down-regulated. We performed pathway enrichment analysis and screened as described previously. Conclusions: The differentially expressed genes might be involved in hepatocarcinogenesis through upregulating the pathways of ECM-receptor interaction, focal adhesion, cell adhesion molecules and other cancer-related pathways, and downregulating the pathways of "complement and coagulation cascades". We hope our results could aid in seeking of therapeutic targets for HCV-induced hepatocellular carcinoma.
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Sensory involvement in the SOD1-G93A mouse model of amyotrophic lateral sclerosis
Yan-Su Guo,Dong-Xia Wu,Hong-Ran Wu,Shu-Yu Wu,Cheng Yang,Bin Li,Hui Bu,Yue-sheng Zhang,Chun-Yan Li 생화학분자생물학회 2009 Experimental and molecular medicine Vol.41 No.3
A subset of patients of amyotrophic lateral sclerosis (ALS) present with mutation of Cu/Zn superoxide dismutase 1 (SOD1), and such mutants caused an ALSlike disorder when expressed in rodents. These findings implicated SOD1 in ALS pathogenesis and made the transgenic animals a widely used ALS model. However, previous studies of these animals have focused largely on motor neuron damage. We report herein that the spinal cords of mice expressing a human SOD1 mutant (hSOD1-G93A), besides showing typical destruction of motor neurons and axons, exhibit significant damage in the sensory system, including Wallerian-like degeneration in axons of dorsal root and dorsal funiculus, and mitochondrial damage in dorsal root ganglia neurons. Thus, hSOD1-G93A mutation causes both motor and sensory neuropathies, and as such the disease developed in the transgenic mice very closely resembles human ALS. A subset of patients of amyotrophic lateral sclerosis (ALS) present with mutation of Cu/Zn superoxide dismutase 1 (SOD1), and such mutants caused an ALSlike disorder when expressed in rodents. These findings implicated SOD1 in ALS pathogenesis and made the transgenic animals a widely used ALS model. However, previous studies of these animals have focused largely on motor neuron damage. We report herein that the spinal cords of mice expressing a human SOD1 mutant (hSOD1-G93A), besides showing typical destruction of motor neurons and axons, exhibit significant damage in the sensory system, including Wallerian-like degeneration in axons of dorsal root and dorsal funiculus, and mitochondrial damage in dorsal root ganglia neurons. Thus, hSOD1-G93A mutation causes both motor and sensory neuropathies, and as such the disease developed in the transgenic mice very closely resembles human ALS.
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