Variations of the stress intensity factors for a planar crack parallel to a bimaterial interface

Chunhui Xu,Taiyan Qin,Li Yuan,Nao-Aki Noda 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.30 No.3

Stress intensity factors for a planar crack parallel to a bimaterial interface are considered. The formulation leads to a system of hypersingular integral equations whose unknowns are three modes of crack opening displacements. In the numerical analysis, the unknown displacement discontinuities are approximated by the products of the fundamental density functions and polynomials. The numerical results show that the present method yields smooth variations of stress intensity factors along the crack front accurately. The mixed mode stress intensity factors are indicated in tables and figures with varying the shape of crack, distance from the interface, and elastic constants. It is found that the maximum stress intensity factors normalized by root area are always insensitive to the crack aspect ratio. They are given in a form of formula useful for engineering applications.

Variations of the stress intensity factors for a planar crack parallel to a bimaterial interface

Xu, Chunhui,Qin, Taiyan,Yuan, Li,Noda, Nao-Aki Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.30 No.3

Stress intensity factors for a planar crack parallel to a bimaterial interface are considered. The formulation leads to a system of hypersingular integral equations whose unknowns are three modes of crack opening displacements. In the numerical analysis, the unknown displacement discontinuities are approximated by the products of the fundamental density functions and polynomials. The numerical results show that the present method yields smooth variations of stress intensity factors along the crack front accurately. The mixed mode stress intensity factors are indicated in tables and figures with varying the shape of crack, distance from the interface, and elastic constants. It is found that the maximum stress intensity factors normalized by root area are always insensitive to the crack aspect ratio. They are given in a form of formula useful for engineering applications.

Changes of Carbohydrates Metabolism and Enzymes Activities in Low Temperature Storage for Bulbs of Lilium Oriental hybrids

Yiping Xia,Chunhui Huang,Guifang He,Weiwei Xu 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

A Multi-Mechanisms Composite Frequency Up-Conversion Energy Harvester

Ping Li,Nuo Xu,Chunhui Gao 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.9

In this paper, a novel broadband hybrid piezoelectric-electromagnetic-electrostatic energy harvester with frequency up conversion is proposed to improve the harvesting bandwidth and energy conversion efficiency. The designed device generates vibration energy with much higher frequency than ambient vibration frequency, which uses the magnet to impact periodically on the piezoelectric cantilever with the top electrode of electrostatic element. The dynamic model of the hybrid energy harvester is established, and performances are experimental tested under the sinusoidal excitation and practical application environment. The results show that multi-mechanisms composite structure can realize the complementary advantages of electrostatic-piezoelectric-electromagnetic mechanisms and improve the energy conversion efficiency effectively compared with a single harvesting mechanism. The fabricated harvester can output electric energy in the frequency range of 1–38 Hz, which significantly reduces frequency dependence, and the maximum power is measured to be 11.7 mW and 12 mW during cycling and walking respectively, which is the sum of the power generated by three different elements. Furthermore, the fabricated prototype can also light up six light-emitting diodes (LEDs) simultaneously when handy shaking.

Up-regulation of NHE8 by somatostatin ameliorates the diarrhea symptom in infectious colitis mice model

Lei, Xuelian,Cai, Lin,Li, Xiao,Xu, Hua,Geng, Chong,Wang, Chunhui The Korean Society of Pharmacology 2018 The Korean Journal of Physiology & Pharmacology Vol.22 No.3

$Na^+/H^+$ exchangers (NHEs) have been shown to be involved in regulating cell volume and maintaining fluid and electrolyte homeostasis. Pooled evidences have suggested that loss of $Na^+/H^+$ exchanger isoform 8 (NHE8) impairs intestinal mucosa. Whether NHE8 participates in the pathology of infectious colitis is still unknown. Our previous study demonstrated that somatostatin (SST) could stimulate the expression of intestinal NHE8 so as to facilitate $Na^+$ absorption under normal condition. This study further explored whether NHE8 participates in the pathological processes of infectious colitis and the effects of SST on intestinal NHE8 expression in the setting of infectious colitis. Our data showed that NHE8 expression was reduced in Citrobacter rodentium (CR) infected mice. Up-regulation of NHE8 improved diarrhea symptom and mucosal damage induced by CR. In vitro, a similar observation was also seen in Enteropathogenic E. coli (EPEC) infected Caco-2 cells. Seglitide, a SST receptor (SSTR) 2 agonist, partly reversed the inhibiting action of EPEC on NHE8 expression, but SSTR5 agonist (L-817,818) had no effect on the expression of NHE8. Moreover, SST blocked the phosphorylation of p38 in EPEC-infected Caco-2 cells. Taken together, these results suggest that enhancement of intestinal NHE8 expression by SST could ameliorate the symptoms of mice with infectious colitis.

Up-regulation of NHE8 by somatostatin ameliorates the diarrhea symptom in infectious colitis mice model

Xuelian Lei,Lin Cai,Xiao Li,Hua Xu,Chong Geng,Chunhui Wang 대한약리학회 2018 The Korean Journal of Physiology & Pharmacology Vol.22 No.3

Na+/H+ exchangers (NHEs) have been shown to be involved in regulating cell volume and maintaining fluid and electrolyte homeostasis. Pooled evidences have suggested that loss of Na+/H+ exchanger isoform 8 (NHE8) impairs intestinal mucosa. Whether NHE8 participates in the pathology of infectious colitis is still unknown. Our previous study demonstrated that somatostatin (SST) could stimulate the expression of intestinal NHE8 so as to facilitate Na+ absorption under normal condition. This study further explored whether NHE8 participates in the pathological processes of infectious colitis and the effects of SST on intestinal NHE8 expression in the setting of infectious colitis. Our data showed that NHE8 expression was reduced in Citrobacter rodentium (CR) infected mice. Up-regulation of NHE8 improved diarrhea symptom and mucosal damage induced by CR. In vitro, a similar observation was also seen in Enteropathogenic E. coli (EPEC) infected Caco-2 cells. Seglitide, a SST receptor (SSTR) 2 agonist, partly reversed the inhibiting action of EPEC on NHE8 expression, but SSTR5 agonist (L-817,818) had no effect on the expression of NHE8. Moreover, SST blocked the phosphorylation of p38 in EPEC-infected Caco-2 cells. Taken together, these results suggest that enhancement of intestinal NHE8 expression by SST could ameliorate the symptoms of mice with infectious colitis.

Zebra-Crossing Automatic Recognition and Early Warning for Intelligent Driving

Mingli Yang,Hua Shi,Yihui Chen,Xiangjin Ran,Chunhui Xu 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.8

Zebra-crossing Recognition is one of the essential parts of the visual based intelligent vehicle navigation or intelligent driving assistant system. In order to address the real-time and robustness, Zebra-crossing Recognition Method which is based on spatial-temporal correlation has been proposed. Firstly, calibrate a camera mounted on the vehicle by a practical method. Then, according to the prior knowledge such from GPS etc, a judgment whether it's in the Crossing area is made. Next, utilize the bipolar property of Zebra-crossing to extract features. Finally, the recognition results are obtained according to the model constraints. In this paper, proposed methods can improve real time identification of the zebra line by using spatial correlation, reduce the cost of recognition and lower errors during identification. The method overcomes some disadvantages of traditional identification approaches based upon video recognition, for instance higher cost and errors.

Integrated proteomic and metabolomic analyses reveal significant changes in chloroplasts and mitochondria of pepper (Capsicum annuum L.) during Sclerotium rolfsii infection

Liao Hongdong,Wen Xiangyu,Deng Xuelei,Wu Yonghong,Xu Jianping,Li Xin,Zhou Shudong,Li Xuefeng,Zhu Chunhui,Luo Feng,Ma Yanqing,Zheng Jingyuan 한국미생물학회 2022 The journal of microbiology Vol.60 No.5

Infection by Sclerotium rolfsii will cause serious disease and lead to significant economic losses in chili pepper. In this study, the response of pepper during S. rolfsii infection was explored by electron microscopy, physiological determination and integrated proteome and metabolome analyses. Our results showed that the stomata of pepper stems were important portals for S. rolfsii infection. The plant cell morphology was significantly changed at the time of the fungal hyphae just contacting (T1) or surrounding (T2) the pepper. The chlorophyll, carotenoid, and MDA contents and the activities of POD, SOD, and CAT were markedly upregulated at T1 and T2. Approximately 4129 proteins and 823 metabolites were clearly identified in proteome and metabolome analyses, respectively. A change in 396 proteins and 54 metabolites in pepper stem tissues was observed at T1 compared with 438 proteins and 53 metabolites at T2. The proteins and metabolites related to photosynthesis and antioxidant systems in chloroplasts and mitochondria were disproportionally affected by S. rolfsii infection, impacting carbohydrate and amino acid metabolism. This study provided new insights into the response mechanism in pepper stems during S. rolfsii infection, which can guide future work on fungal disease resistance breeding in pepper.

Effects of exposure to trace pyriproxyfen on the intestinal bacterial diversity and immune signal pathways of silkworm (Bombyx mori) larvae

Lu Qingyu,Li Guoli,Lan Huangli,Yu Dongliang,Yin Xingcan,Yang Wenqi,Yang Zehao,He Chunhui,Mo Danmei,Xu Kaizun 한국응용곤충학회 2022 Journal of Asia-Pacific Entomology Vol.25 No.2

Silkworm (Bombyx mori) is a widely used lepidopteran model insect. Pyriproxyfen is an insect growth regulator (IGR) that can be used to control pests such as lepidoptera and diptera, and there is no research about its in fluence on the intestinal bacterial diversity and immune signal pathway of non-target lepidopteran insect larvae. In this study, we treated fifth-instar silkworms with trace pyriproxyfen (10 − 4 mg/L). The results showed that the abundance and diversity of silkworm larvae intestinal flora at the level of phylum, class, order, family and genus were all changed. The function prediction result showed that the functional changes mainly focused on tran scription, amino acid transport and metabolism, carbohydrate transport and metabolism, signal transduction mechanisms, energy production and conversion et al. after exposure to trace pyriproxyfen. Furthermore, qRTPCR results showed that trace pyriproxyfen exposure activated the transcriptions of antimicrobial peptides (AMPs) genes regulated by Toll and IMD pathways. This research can lay the foundation for the study on the resistance of lepidopteran insects to pyriproxyfen and other juvenile hormone pesticides.