Elastic-plastic-creep response of multilayered systems under cyclic thermo-mechanical loadings

Xiaotao Zheng,Jiqiang Wang,Wei Wang,Linwei Ma,Wei Lin,Jiuyang Yu 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.3

The modified Ohno and Abdel-Karim nonlinear kinematic hardening model considering cyclic hardening and creep effect are developed to investigate the deformation and residual stress of multilayered systems subjected to cyclic thermal and mechanical loads. Results reveal that, if the creep behavior is considered, significant stress relaxation takes place during about the first several cycles, and the accumulated strain of multilayered systems under deformation-controlled loads finally remains constant, which leads to shakedown. Remarkable changes of the residual stress, location of neutral axis and curvature of Si-Cu beams are observed during about the first 100 cycles. Therefore, the proposed model can be used for the engineering design of multilayered systems under complex loads.

Numerical simulation of surface roughness effects on the vortex-induced vibration of a circular cylinder at a subcritical Reynolds number

Chen Wei,Wang Siying,Shi Xiaotao,Rheem Chang-Kyu,Lin Yongshui,Liu Erpeng 대한조선학회 2022 International Journal of Naval Architecture and Oc Vol.14 No.1

The Vortex-Induced Vibration (VIV) of a circular cylinder with different surface roughness is numerically simulated at a subcritical Reynolds number of 3900. The effects of surface roughness on the vibration response amplitude, hydrodynamic coefficients and wake vortex are analyzed. The results show that as surface roughness increases, four branches (initial, upper, super-upper and lower branches) appear in the VIV response for a smooth cylinder, and for a cylinder with a small surface roughness of KS=D ¼ 2:5 103 , this response changes to three branches (initial, upper and lower branches). The vortex shedding for the initial and lower branches is 2S mode, and that for the upper and super-upper branches (lock-in range) is P þ S, PþSþ and 2P modes. With increasing surface roughness, the maximum amplitude has little difference, and the width of the lock-in range increases. A large jump in the vortex phase at the transition of the initial and upper branches and a large jump in the total lift phase at the transition of the upper and lower branches are found, and these jumps are associated with a switch in the timing of vortex shedding (jump of the vortex phase: 2S mode to P þ S mode; jump of the lift phase: other modes to 2S mode). The results are significant for the development of flow and vibration control technology.

On TEC anomalies as precursor before MW 8.6 Sumatra earthquake and MW 6.7 Mexico earthquake on April 11, 2012

Jinyun Guo,Wang Li,Xin Liu,Jianbo Wang,Xiaotao Chang,Chunmei Zhao 한국지질과학협의회 2015 Geosciences Journal Vol.19 No.4

To investigate the coupling relationship between earthquake and ionosphere perturbation, we process the global total electron contents (TECs) estimated from GPS data of IGS stations by CODE and analyze TEC anomalies before MW 8.6 Sumatra earthquake and MW 6.7 Mexico earthquake on April 11, 2012. The sliding interquartile method with the sliding window of 27 days is used to process data of SSN, F10.7 solar flux, Dst and Kp to eliminate the effects of solar activity and the geomagnetic activity. The results show that there are positive and negative TEC anomalies over epicenter on the 11th day and the 3rd day prior to the Sumatran earthquake respectively. But the decrement and increment of TEC anomalies over epicenter occurred on the 11th day and the 3rd day prior to the Mexico earthquake. The global TEC anomalies are analyzed on the 11th day and the 3rd day before these two great earthquakes, respectively. The magnitudes of TEC anomaly occurred on the 3rd day before earthquakes are larger than that occurred on the 11th day before earthquakes. This indicates the magnitude of anomaly may be related to the number of days prior to earthquake. But the magnitude of TEC anomaly near Sumatran is lower than that near Mexico, and the duration of anomalies occurred on 11th day is longer than those on 3rd day prior to earthquake, which are different from previous results. The TEC anomaly of Sumatran earthquake mainly occurs in the afternoon and night local time, but the TEC anomaly of Mexico earthquake mainly occurs in the morning local time. The TEC anomaly peak regions before these two earthquakes appeared on the south of epicenters instead of the vertical projection of the epicenter. Corresponding ionospheric anomalies are also observed in the magnetically conjugated regions. These can be guidance for the ionosphere monitoring in earthquake study.

Efficacy and Safety of Pulse Magnetic Therapy System in Insomnia Disorder: A Multicenter, Randomized, Double-Blind, Placebo-Controlled Trial

Liao Jiwu,Wang Sisi,Zhou Borong,Liang Wei,Ma Ping,Lin Min,Lin Weisen,Li Congrui,Zhang Xiaotao,Li Hongyao,Cui Yin,Hu Jiajia,Qin Yuanyi,Deng Yanhua,Fu Aibing,Zhu Tianhua,Zhang Shanlian,Qu Yunhong,Xing L 대한신경정신의학회 2023 PSYCHIATRY INVESTIGATION Vol.20 No.6

Objective This study’s objective is to assess the efficacy and safety of Pulsed Magnetic Therapy System (PMTS) in improving insomnia disorder.Methods Participants with insomnia disorder were randomly assigned to receive either PMTS or sham treatment for four weeks (n= 153; PMTS: 76, sham: 77). Primary outcomes are the Insomnia Severity Index (ISI) scores at week 0 (baseline), 1, 2, 3, 4 (treatment), and 5 (follow-up). Secondary outcomes are the Pittsburgh Sleep Quality Index at baseline and week 4, and weekly sleep diary-derived values for sleep latency, sleep efficiency, real sleep time, waking after sleep onset, and sleep duration.Results The ISI scores of the PMTS group and the sham group were 7.13±0.50, 11.07±0.51 at week 4, respectively. There was a significant group×time interaction for ISI (F3.214, 485.271=24.25, p<0.001, ηp 2=0.138). Only the PMTS group experienced continuous improvement throughout the study; in contrast, the sham group only experienced a modest improvement after the first week of therapy. At the end of the treatment and one week after it, the response of the PMTS group were 69.7% (95% confidence interval [CI]: 58.6%–79.0%), 75.0% (95% CI: 64.1%–83.4%), respectively, which were higher than the response of the sham group (p<0.001). For each of the secondary outcomes, similar group×time interactions were discovered. The effects of the treatment persisted for at least a week.Conclusion PMTS is safe and effective in improving insomnia disorders.

A new device for restraining rail vibration of ballastless track and its effect study

Zhenxing He,Xu Zhang,Xiaotao Wang,Hualong Zhou,Quanbao Feng,Qingchao Chen,Junxia Chen,Yanbo Bai,Runxi Zhang,Nengneng Bao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.8

A new type of rail vibration damping device (NTRVDV), which is arranged between the bottom of the rail and track bed, is proposed in this paper. The finite element model of the rail system with the NTRVDV and tuned rail damper (TRD) was established, respectively. The impact load was applied to the finite element model, and comparison of the set of existing TRD and NTRVDV on the dynamic response of rail and rail vibration decay rate. The effect of the stiffness change of the elastic layer of the NTRVDV on the rail vibration was studied, and a hammering test verified the theoretical research results. The research results show that compared with the traditional TRD, the NTRVDV has a more obvious suppression effect on rail vibration acceleration. The rail vibration decay rate is significantly improved, especially in the low-frequency stage. With the increase of the stiffness of the elastic layer of the vibration suppression device, the vibration suppression effect of the NTRVDV on the rail is improved. The change of the elastic layer stiffness significantly impacts the rail’s vibration suppression effect in the range of 0-7 kN/mm.

Association between Retinal Vascular Geometric Changes and Cognitive Impairment: A Systematic Review and Meta-Analysis

Huiqun Wu,Chendong Wang,Cong Chen,Xiaotao Xu,Yi Zhu,Aimin Sang,Kui Jiang,Jiancheng Dong 대한신경과학회 2020 Journal of Clinical Neurology Vol.16 No.1

Background and Purpose Previous studies have explored the association between retinal vascular changes and cognitive impairment. The retinal vasculature shares some characteristics with the cerebral vasculature, and quantitative changes in it could indicate cognitive impairment. Hence, a comprehensive meta-analysis was performed to clarify the potential relationship between retinal vascular geometric changes and cognitive impairment. Methods Relevant databases were scrupulously and systematically searched for retinal vascular geometric changes including caliber, tortuosity, and fractal dimension (FD), and for cognitive impairment. The Newcastle-Ottawa Scale was used to evaluate the methodological quality of included studies. RevMan was used to perform the meta-analysis and detect publication bias. Sensitivity analyses were also performed. Results Five studies that involved 2,343 subjects were finally included in the meta-analysis. The results showed that there was no significant association between central retinal artery equivalents (Z=1.17) or central retinal venular equivalents (Z=1.74) and cognitive impairment (both p>0.05). Similarly, no significant difference was detected in retinal arteriolar tortuosity (Z=0.91) and venular tortuosity (Z=1.31) (both p>0.05). However, the retinal arteriolar FD (mean difference: -0.03, 95% CI: -0.05, -0.01) and venular FD (mean difference: -0.03, 95% CI: -0.05, -0.02) were associated with cognitive impairment. Conclusions A smaller retinal microvascular FD might be associated with cognitive impairment. Further large-sample and well-controlled original studies are required to confirm the present findings.

GPS Navigation Information Processing and Display Based on VC+

Feijiang Huang,Zhaofeng Li,Xiaochun Lu,Wang Sheng,Liping Sun,Xiaotao Wei,Guangcan Liu 보안공학연구지원센터(IJSIP) 2013 International Journal of Signal Processing, Image Vol.6 No.4

A Multi-Criteria QoS-aware Trust Service Composition Algorithm in Cloud Computing Environments

Weina Lu,Xiaohui Hu,Shangguang Wang,Xiaotao Li 보안공학연구지원센터(IJGDC) 2014 International Journal of Grid and Distributed Comp Vol.7 No.1

Structural Conservation and Food Habit-related Liver Expression of Uncoupling Protein 2 Gene in Five Major Chinese Carps

Liao, Wan-Qin,Liang, Xu-Fang,Wang, Lin,Fang, Ling,Lin, Xiaotao,Bai, Junjie,Jian, Qing Korean Society for Biochemistry and Molecular Biol 2006 Journal of biochemistry and molecular biology Vol.39 No.4

The full-length cDNA of grass carp (Ctenopharyngodon idellus) and silver carp (Hypophthalmichthys molitrix) uncoupling protein 2 (UCP2) was obtained from liver. The grass carp UCP2 cDNA was determined to be 1152 bp in length with an open reading frame that encodes 310 amino acids. Five introns (Intron 3, 4, 5, 6 and 7) in the translated region, and partial sequence of Intron 2 in the untranslated region of grass carp UCP2 gene were also obtained. Gene structure comparison between grass carp and mammalian (human and mouse) UCP2 gene shows that, the UCP2 gene structure of grass carp is much similar to that of human and mouse. Partial UCP2 cDNA sequences of bighead carp (Aristichthys nobilis) and mud carp (Cirrhinus molitorella), were further determined. Together with the common carp (Cyprinus carpio) UCP2 sequence from GenBank (AJ243486), multiple alignment result shows that the nucleotide and amino acid sequences of the UCP2 gene, were highly conserved among the five major Chinese carps that belong to four subfamilies. Using beta-actin as control, the ratio UCP2/beta-actin mRNA (%) was determined to be $149.4{\pm}15.6$ (common carp), $127.4{\pm}22.1$ (mud carp), $96.7{\pm}12.7$ (silver carp), $94.1{\pm}26.8$ (bighead carp) and $63.7{\pm}16.2$ (grass carp). The relative liver UCP2 expression of the five major Chinese carps, shows a close relationship with their food habit: benthos and detrituseating fish (common carp and mud carp) > planktivorious fish (silver carp and bighead carp) > herbivorious fish (grass carp). We suggest that liver UCP2 might be important for Chinese carps to detoxify cyanotoxins and bacteria in debris and plankton food.

Lineage conversion of mouse fibroblasts to pancreatic α-cells

Lijian Hui,Liangliang Sun,Beige Jiang,Limei Li,Jin Cen,Xiaotao Chen,Zhaoyun Zhang,Qinghua Wang,Xin Cheng,Yongquan Shi,Lijian Hui 생화학분자생물학회 2017 Experimental and molecular medicine Vol.49 No.-

α-cells, which synthesize glucagon, also support β-cell survival and have the capacity to transdifferentiate into β-cells. However, the role of α-cells in pathological conditions and their putative clinical applications remain elusive due in large part to the lack of mature α-cells. Here, we present a new technique to generate functional α-like cells. α-like cells (iAlpha cells) were generated from mouse fibroblasts by transduction of transcription factors, including Hhex, Foxa3, Gata4, Pdx1 and Pax4, which induce α-cell-specific gene expression and glucagon secretion in response to KCl and Arg stimulation. The cell functions in vivo and in vitro were evaluated. Lineage-specific and functional-related gene expression was tested by realtime PCR, insulin tolerance test (ITT), glucose tolerance test (GTT), Ki67 and glucagon immunohistochemistry analysis were done in iAlpha cells transplanted nude mice. iAlpha cells possess α-cell function in vitro and alter blood glucose levels in vivo. Transplantation of iAlpha cells into nude mice resulted in insulin resistance and increased β-cell proliferation. Taken together, we present a novel strategy to generate functional α-like cells for the purposes of disease modeling and regenerative medicine.