Exact integration for the hypersingular boundary integral equation of two-dimensional elastostatics

Xiaosong Zhang,Xiaoxian Zhang 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.30 No.3

This paper presents an exact integration for the hypersingular boundary integral equation of two-dimensional elastostatics. The boundary is discretized by straight segments and the physical variables are approximated by discontinuous quadratic elements. The integral for the hypersingular boundary integral equation analysis is given in a closed form. It is proven that using the exact integration for discontinuous boundary element, the singular integral in the Cauchy Principal Value and the hypersingular integral in the Hadamard Finite Part can be obtained straightforward without special treatment. Two numerical examples are implemented to verify the correctness of the derived exact integration.

Exact integration for the hypersingular boundary integral equation of two-dimensional elastostatics

Zhang, Xiaosong,Zhang, Xiaoxian Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.30 No.3

This paper presents an exact integration for the hypersingular boundary integral equation of two-dimensional elastostatics. The boundary is discretized by straight segments and the physical variables are approximated by discontinuous quadratic elements. The integral for the hypersingular boundary integral equation analysis is given in a closed form. It is proven that using the exact integration for discontinuous boundary element, the singular integral in the Cauchy Principal Value and the hypersingular integral in the Hadamard Finite Part can be obtained straightforward without special treatment. Two numerical examples are implemented to verify the correctness of the derived exact integration.

Kinetics of 5-Hydroxymethylfurfural Formation in Chinese Acacia Honey during Heat Treatment

Yuyu Zhang,Yi Song,Tingting Zhou,Xiaojun Liao,Xiaosong Hu,Quanhong Li 한국식품과학회 2012 Food Science and Biotechnology Vol.21 No.6

In this paper, the 5-hydroxymethylfurfural (HMF) contents of the acacia honeys after heat treatment were determined by HPLC; the kinetics of HMF formation was also investigated. The HMF content of acacia honey was 0.38±0.01mg/kg, but rapidly increased to the maximum of 18,320.07±14.29 mg/kg at 190oC and decreased to 1,180.24±6.54 mg/kg at 230oC after heating. The HMF content increased gradually in honey samples heated in 12h at the temperature of 80, 100, and 120oC. The apparent frequency constant was kf =3.91×1025/h, and the apparent activation energy was Ea=173.10 kJ/mol. The HMF content in the acacia honey was related to honey composition,heating temperature, and time, and the HMF formation could also be related to the initial honey pH.

An OSSE Study for Deep Argo Array using the GFDL Ensemble Coupled Data Assimilation System

장유순,Shaoqing Zhang,Anthony Rosati,Gabriel A. Vecchi,Xiaosong Yang 한국해양과학기술원 2018 Ocean science journal Vol.53 No.2

An observing system simulation experiment (OSSE) using an ensemble coupled data assimilation system was designed to investigate the impact of deep ocean Argo profile assimilation in a biased numerical climate system. Based on the modern Argo observational array and an artificial extension to full depth, “observations” drawn from one coupled general circulation model (CM2.0) were assimilated into another model (CM2.1). Our results showed that coupled data assimilation with simultaneous atmospheric and oceanic constraints plays a significant role in preventing deep ocean drift. However, the extension of the Argo array to full depth did not significantly improve the quality of the oceanic climate estimation within the bias magnitude in the twin experiment. Even in the “identical” twin experiment for the deep Argo array from the same model (CM2.1) with the assimilation model, no significant changes were shown in the deep ocean, such as in the Atlantic meridional overturning circulation and the Antarctic bottom water cell. The small ensemble spread and corresponding weak constraints by the deep Argo profiles with medium spatial and temporal resolution may explain why the deep Argo profiles did not improve the deep ocean features in the assimilation system. Additional studies using different assimilation methods with improved spatial and temporal resolution of the deep Argo array are necessary in order to more thoroughly understand the impact of the deep Argo array on the assimilation system.

An OSSE Study for Deep Argo Array using the GFDL Ensemble Coupled Data Assimilation System

Chang, You-Soon,Zhang, Shaoqing,Rosati, Anthony,Vecchi, Gabriel A.,Yang, Xiaosong Korean Ocean Research & Development Institute and 2018 OCEAN SCIENCE JOURNAL Vol.53 No.2

An observing system simulation experiment (OSSE) using an ensemble coupled data assimilation system was designed to investigate the impact of deep ocean Argo profile assimilation in a biased numerical climate system. Based on the modern Argo observational array and an artificial extension to full depth, 'observations' drawn from one coupled general circulation model (CM2.0) were assimilated into another model (CM2.1). Our results showed that coupled data assimilation with simultaneous atmospheric and oceanic constraints plays a significant role in preventing deep ocean drift. However, the extension of the Argo array to full depth did not significantly improve the quality of the oceanic climate estimation within the bias magnitude in the twin experiment. Even in the 'identical' twin experiment for the deep Argo array from the same model (CM2.1) with the assimilation model, no significant changes were shown in the deep ocean, such as in the Atlantic meridional overturning circulation and the Antarctic bottom water cell. The small ensemble spread and corresponding weak constraints by the deep Argo profiles with medium spatial and temporal resolution may explain why the deep Argo profiles did not improve the deep ocean features in the assimilation system. Additional studies using different assimilation methods with improved spatial and temporal resolution of the deep Argo array are necessary in order to more thoroughly understand the impact of the deep Argo array on the assimilation system.

Chitosan Nerve Grafts Incorporated with SKP-SC-EVs Induce Peripheral Nerve Regeneration

Zhou Xinyang,Yu Miaomei,Chen Daiyue,Deng Chunyan,Zhang Qi,Gu Xiaosong,Ding Fei 한국조직공학과 재생의학회 2023 조직공학과 재생의학 Vol.20 No.2

BACKGROUND: Repair of long-distance peripheral nerve defects remains an important clinical problem. Nerve grafts incorporated with extracellular vesicles (EVs) from various cell types have been developed to bridge peripheral nerve defects. In our previous research, EVs obtained from skin-derived precursor Schwann cells (SKP-SC-EVs) were demonstrated to promote neurite outgrowth in cultured cells and facilitate nerve regeneration in animal studies. METHODS: To further assess the functions of SKP-SC-EVs in nerve repair, we incorporated SKP-SC-EVs and Matrigel into chitosan nerve conduits (EV-NG) for repairing a 15-mm long-distance sciatic nerve defect in a rat model. Behavioral analysis, electrophysiological recording, histological investigation, molecular analysis, and morphometric assessment were carried out. RESULTS: The results revealed EV-NG significantly improved motor and sensory function recovery compared with nerve conduits (NG) without EVs incorporation. The outgrowth and myelination of regenerated axons were improved, while the atrophy of target muscles induced by denervation was alleviated after EVs addition. CONCLUSION: Our data indicated SKP-SC-EVs incorporation into nerve grafts represents a promising method for extended peripheral nerve damage repair.

RNA sequencing reveals lncRNA-mediated non-mendelian inheritance of feather growth change in chickens

Qiu Mohan,Yu Chunlin,Zhu Shiliang,Liu Siyang,Peng Han,Xiong Xia,Chen Jialei,Jiang Xiaosong,Du Huarui,Li Qingyun,Zhang Zengrong,Yang Chaowu 한국유전학회 2022 Genes & Genomics Vol.44 No.11

Background: Long non-coding RNAs (lncRNAs) play an essential role in biological processes. However, the expression patterns of lncRNAs that regulate the non-Mendelian inheritance feather phenotypes remain unknown. Objective: This study aimed to compare the expression profiles of lncRNAs in the follicles of the late-feathering cocks (LC) and late-feathering hens (LH) that followed genetic rules and the early-feathering hen (EH) and early-feathering cock (EC) that did not conform to the genetic laws. Methods: We performed RNA sequencing and investigated the differentially expressed lncRNAs (DElncRNAs) between the early- and late-feathering chickens, which function by cis-acting or participate in the competing endogenous RNA (ceRNA) network. Results: A total of 53 upregulated and 43 downregulated lncRNAs were identified in EC vs. LC, and 58 upregulated and 109 downregulated lncRNAs were identified in EH vs. LH. The target mRNAs regulated by lncRNAs in cis were enriched in the pentose phosphate pathway, TGF-β signaling pathway and Jak-STAT signaling pathway in EC vs. LC and were associated with the TGF-β signaling pathway, Wnt signaling pathway, p53 signaling pathway and Jak-STAT signaling pathway in EH vs. LH. In addition, the lncRNA-mediated ceRNA regulatory pathways of hair follicle formation were mainly enriched in the TGF-β signaling pathway, Wnt signaling pathway, melanogenesis, and calcium signaling pathways. The levels of ENSGALG00000047626 were significantly higher in the late-feathering chickens than in the early-feathering chickens, which regulated the expression of SSTR2 by gga-miR-1649-5p. Conclusion: This study provides a novel molecular mechanism of lncRNA's response to the feather rate that does not conform to the genetic laws in chickens.

An Investigation into the Characteristics of a Novel Rotatable Pantograph Catenary System for High-Speed Trains

Xiao Song,Luo Yuanpei,Wu Jingchi,Zhang Can,Rao Yang,Wu Guangning,Deng Zhida,Sykulski Jan K. 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.3

High speed trains receive traction electrical energy from a high-voltage catenary via a pantograph catenary system (PCS). As the velocity of trains increases, the traditional PCSs face signifi cant challenges, such as strong aero resistance under highspeed conditions, severe electrochemical corrosion caused by poor contact between the pantograph strip and the catenary, harmful wear both on the pantograph strip and the contact wire produced by high-speed sliding friction between them, etc. The eff ectiveness and reliability of the PCS has a direct impact on the performance and safety of the HTS power supply. In order to alleviate some of these bottleneck eff ects related to the operation of the currently used PCSs, especially under high-speed conditions, this paper proposes a novel confi guration where rotatable pantograph rollers replace the currently used pantograph strips. As the sliding friction is now replaced by rotating friction, this has numerous benefi ts, such as less friction heat, better heat dispersion and improved catenary-tracking performance. Moreover, should the whole system be modularized, it could adapt to diff erent levels of traction power through adjusting the number of rollers.