Performance Analysis of IEEE 802.15.4e Time Slotted Channel Hopping for Low-Rate Wireless Networks

( Shuguang Chen ),( Tingting Sun ),( Jingjing Yuan ),( Xiaoyan Geng ),( Changle Li ),( Sana Ullah ),( Mohammed Abdullah Alnuem ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.1

The release of IEEE 802.15.4e specification significantly develops IEEE 802.15.4. The most inspiring improvement is the enhancement for medium access control (MAC) sublayer. To study the performance of IEEE 802.15.4e MAC, in this paper we first present an overview of IEEE 802.15.4e and introduce three MAC mechanisms in IEEE 802.15.4e. And the major concern here is the Time Slotted Channel Hopping (TSCH) mode that provides deterministic access and increases network capacity. Then a detailed analytical Markov chain model for TSCH carrier sense multiple access with collision avoidance (CSMA-CA) is presented. Expressions which cover most of the crucial issues in performance analysis such as the packet loss rate, energy consumption, normalized throughput, and average access delay are presented. Finally the performance evaluation for the TSCH mode is given and we make a comprehensive comparison with unslotted CSMA-CA in non-beacon enabled mode of IEEE 802.15.4. It can validate IEEE 802.15.4e network can provide low energy consumption, deterministic access and increase network capacity.

Discussion on Failure Mechanism and Strength Criterion of Sandstone Based on Particle Discrete Element Method

Shuguang Zhang,Lei Chen,Pingping Lu,Wenbo Liu 대한토목학회 2021 KSCE Journal of Civil Engineering Vol.25 No.6

In order to study the mechanism of loading failure process of deep rock mass, particle flow numerical simulation (PFC2D) was used to carry out rock mechanical unit tests under different loading strain rates for sandstone in Haitangshan Tunnel, Fuxin. The applicability of several classical strength criteria was compared according to the test. The results show that, except Poisson's ratio, the other mechanical parameters are positively correlated with the loading strain rate, including peak strength, elastic modulus, cohesion, internal friction angle and tensile strength. And the Poisson's ratio is negatively correlated with the loading strain rate. And the crack initiation stress σci and dilatation stress σcd increased gradually, but the effects on σci/σpk, σcd/σpk and σci/σcd were not obvious; and at the same volume strain, the corresponding axial strain decreased gradually. The anisotropy of normal and tangential contact forces between particles increases with the increase of loading strain rate. The normal contact force was approximately symmetrical distributed up and down, while the tangential contact force was approximately symmetrical distributed in the center. The cumulative number of cracks and the number of cracks every 10 steps gradually increased with the loading strain rate, and the crack development and failure degree gradually increased, and the crack hot spot map at the shear fracture zone gradually tended to be irregular. By comparing different strength criteria, it was found that the error of ROCKER strength criterion was relatively small, and the calculation was simple. It was considered that ROCKER strength criterion was more suitable for sandstone strength prediction under different loading strain rates.

Improved high-k stacks with chemical oxide interfacial layer by DPN/ PNA treatment

Shuguang Li,Ying-Tsung Chen,Shoou-Jinn Chang 한국물리학회 2015 Current Applied Physics Vol.15 No.3

A decoupled plasma nitridation (DPN) with post nitridation annealing (PNA) treatment method was introduced to improve the performances of MOS devices with high-k (HK)-last/gate-last integration scheme and chemical oxide interface layer (IL). By introducing N to form HfSiON, it was found that DPN + PNA treatments could provide smaller equivalent oxide thickness (EOT) for both nMOS and pMOS devices. It was also found that we could achieve the best overall device performance for the HK-last/gatelast integration scheme with a chemical oxide IL by introducing nitrogen gas with low percentage content during DPN followed by high temperature PNA.

Failure Mechanism and Energy Damage Evolution of Deep Sandstone Anchored by Carbon Fiber

Lei Chen,Pingping Lu,Shuguang Zhang 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.4

Deep rock mass engineering usually needs anchoring after excavation, and the strength and deformation characteristics of anchored rock mass will directly affect the safety and stability of underground engineering. Aiming at the state of deep surrounding rock after bolt shotcrete support, this paper takes the sandstone of a tunnel under construction in Guangxi as the research object, innovatively uses carbon fiber to anchor the sandstone in the circumferential direction, so as to simulate the bolt shotcrete support state of deep surrounding rock, and systematically studies the mechanical properties, failure mechanism and energy damage evolution law. The results show that: In this paper, carbon fiber was used as the anchoring material, and the anchoring effect was ideal, which can approximately simulate the bolt shotcrete support state of tunnel surrounding rock; With the gradual increase of anchorage area, the anchorage strength provided by carbon fiber gradually increases, the strength and deformation parameters, shear strength parameters and characteristic stress of anchored sandstone gradually increase, and the failure form gradually changes from single shear failure to shear failure, supplemented by cross through tension cracks, and the dissipated energy, elastic strain energy and total energy corresponding to the peak strength of anchored sandstone gradually increase, while the proportion of elastic and dissipated energy gradually decrease, and the damage variable gradually decreases; Based on the energy dissipation theory, the energy damage evolution equation considering the anchoring effect of carbon fiber was established. The rationality of the energy damage equation was verified by comparing test curves and theoretical curves of different anchoring areas. The research conclusion can provide a reliable theoretical basis for bolt shotcrete support of surrounding rock in deep underground engineering.

Phylogenetic Diversity of Microbial Communities in Real Drinking Water Distribution Systems

Pinpin Lu,Chao Chen,Qingfeng Wang,Zhao Wang,Xiaojian Zhang,Shuguang Xie 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.1

Microbial regrowth in drinking water distribution systems (DWDS) is a major concern in the water supply industry. Detailed knowledge of the microbial community in DWDS will be of great importance for assessing the microbiological risks of drinking water. The spatial heterogeneity of microbial community structures in the bulk waters of a large real DWDS was investigated using 16S rRNA clone library analysis. The results indicate that high residual chlorine in drinking water could not control microbial regrowth in DWDS. The bacterial communities in the bulk waters were spatially heterogenic, mainly composed of Alphaproteobacteria and Betaproteobacteria (or Cyanobacteria). Microorganisms from the genera Acinetobacter, Sphingomonas and Gemella were detected,implying there is microbiological risk from drinking water. This work provides new insight into microbial ecology in DWDS.

Heterogeneity of Microbial Community Structures inside the Up-flow Biological Activated Carbon (BAC) Filters for the Treatment of Drinking Water

Xiaobin Liao,Chao Chen,Chih-Hsiang Chang,Zhao Wang,Xiaojian Zhang,Shuguang Xie 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.4

Filtration using biological activated carbon (BAC) performs well in the removal of biodegradable dissolved organic carbon from water sources. The application of ozonation followed by up-flow BAC filtration has gained increasing attention in the world scale. In this study, a pilotscale up-flow BAC filtration system was constructed for the treatment of polluted lake water. The operational results indicated that this BAC filtration system could effectively remove organic matter. Spatial heterogeneity of the microbial community structure inside the BAC filtration system was identified using bacterial 16S rRNA clone library analysis. A marked decrease of microbial diversity in the BAC filtration system was observed along the flow path. Alphaproteobacteria,Gammaproteobacteria and Acidobacteria were found to be the major bacterial groups in the BAC filters. Moreover, Novosphingobium aromaticivorans-like microorganisms were detected. This work might add some new insights towards microbial communities in regards to BAC filtration for the treatment of drinking water.

Osteogenic and Angiogenic Potency of VEGF165-Transfected Canine Bone Marrow Mesenchymal Cells Combined with Coral Hydroxyapatite in Vitro

Zhang Quanyin,Zhang Jie,Chen Lin,Fan Yunjian,Long Jiazhen,Liu Shuguang 한국조직공학과 재생의학회 2021 조직공학과 재생의학 Vol.18 No.5

BACKGROUND: To explore the osteogenic and angiogenic potential of human vascular endothelial growth factor 165 (hVEGF165) gene-transfected canine bone marrow mesenchymal stem cells (BMSCs) combined with coral hydroxyapatite (CHA) scaffold. METHODS: We constructed a lentiviral vector and transfected canine BMSCs with the best multiplicity of infection. Osteogenesis was induced in the transfected groups (GFP-BMSCs group and hVEGF-BMSCs group) and non-transfected group (BMSCs group), followed by the evaluation of alkaline phosphatase (ALP) activity and alizarin red S staining. Cells from the three groups were co-cultured with CHA granules, respectively to obtain the tissue-engineered bone. MTT assay and fluorescence microscopy were employed to assess cell proliferation and adhesion. The expression of osteogenic and angiogenic related genes and proteins were evaluated at 7, 14, 21, and 28 days post osteoinduction in cell culture alone and cell co-culture with CHA, respectively using RT-PCR and ELISA. RESULTS: The hVEGF165 gene was transfected into BMSCs successfully. Higher ALP activity and more calcified nodules were found in the hVEGF-BMSCs group than in the control groups (p < 0.001). Cells attached and proliferated in CHA particles. Both cells cultured alone and cells co-culture with CHA expressed more osteogenic and angiogenic related genes and proteins in the hVEGF-BMSCs group compared to the GFP-BMSCs and BMSCs groups (p < 0.05). CONCLUSION: High expression of hVEGF165 in BMSCs potentially promote the osteogenic potential of BMSCs, and synergically drive the expression of other osteogenic and angiogenic factors. hVEGF-BMSCs co-cultured with CHA expressed more osteogenic and angiogenic related factors, creating a favorable microenvironment for osteogenesis and angiogenesis. Also, the findings have allowed for the construction of a CHA-hVEGF-BMSCs tissue-engineered bone. BACKGROUND: To explore the osteogenic and angiogenic potential of human vascular endothelial growth factor 165 (hVEGF165) gene-transfected canine bone marrow mesenchymal stem cells (BMSCs) combined with coral hydroxyapatite (CHA) scaffold. METHODS: We constructed a lentiviral vector and transfected canine BMSCs with the best multiplicity of infection. Osteogenesis was induced in the transfected groups (GFP-BMSCs group and hVEGF-BMSCs group) and non-transfected group (BMSCs group), followed by the evaluation of alkaline phosphatase (ALP) activity and alizarin red S staining. Cells from the three groups were co-cultured with CHA granules, respectively to obtain the tissue-engineered bone. MTT assay and fluorescence microscopy were employed to assess cell proliferation and adhesion. The expression of osteogenic and angiogenic related genes and proteins were evaluated at 7, 14, 21, and 28 days post osteoinduction in cell culture alone and cell co-culture with CHA, respectively using RT-PCR and ELISA. RESULTS: The hVEGF165 gene was transfected into BMSCs successfully. Higher ALP activity and more calcified nodules were found in the hVEGF-BMSCs group than in the control groups (p < 0.001). Cells attached and proliferated in CHA particles. Both cells cultured alone and cells co-culture with CHA expressed more osteogenic and angiogenic related genes and proteins in the hVEGF-BMSCs group compared to the GFP-BMSCs and BMSCs groups (p < 0.05). CONCLUSION: High expression of hVEGF165 in BMSCs potentially promote the osteogenic potential of BMSCs, and synergically drive the expression of other osteogenic and angiogenic factors. hVEGF-BMSCs co-cultured with CHA expressed more osteogenic and angiogenic related factors, creating a favorable microenvironment for osteogenesis and angiogenesis. Also, the findings have allowed for the construction of a CHA-hVEGF-BMSCs tissue-engineered bone.

A R2R3-type MYB transcription factor gene from soybean, GmMYB12, is involved in flavonoids accumulation and abiotic stress tolerance in transgenic Arabidopsis

Feibing Wang,Xuqin Ren,Fan Zhang,Mingyang Qi,Huiyun Zhao,Xinhong Chen,Yuxiu Ye,Jiayin Yang,Shuguang Li,Yi Zhang,Yuan Niu,Qing Zhou 한국식물생명공학회 2019 Plant biotechnology reports Vol.13 No.3

The R2R3-type MYB transcription factors have been shown to increase flavonoids accumulation by regulating the expression of key enzyme genes related to flavonoid biosynthesis pathway. However, the roles and underlying mechanisms of the soybean GmMYB12 gene in regulation of flavonoids accumulation and tolerance to abiotic stresses are rarely known. In the present study, the GmMYB12 gene was isolated and its function was characterized. Sequence and yeast one-hybrid analyses showed that GmMYB12 contained two MYB domains and belonged to R2R3-MYB protein with transactivation activity. Subcellular localization analysis in onion epidermal cells indicated that GmMYB12 was localized to the nucleus. Overexpression of GmMYB12 increased the production of downstream flavonoids and the expression of related genes in the flavonoid biosynthesis pathway. It also improved resistance to salt and drought stresses during seed germination, root development, and growing stage. Further component and enzymatic analyses showed significant increases of proline content, pyrroline-5-carboxylate synthase (P5CS), superoxide dismutase (SOD), and peroxidase (POD) activities, as well as significant reduction of H2O2 and malonaldehyde (MDA) content under salt and drought stresses in transgenic plants. Meanwhile, the expression level of AtP5CS, AtSOD and AtPOD genes was up-regulated against salt and drought stresses. Together, our finding indicated that changing the expression level of GmMYB12 in plants alters the accumulation of flavonoids and regulates plantlet tolerance to abiotic stress by regulating osmotic balance, protecting membrane integrity and maintaining ROS homeostasis. The GmMYB12 gene has the potential to be used to increase the content of valuable flavonoids and improve the tolerance to abiotic stresses in plants

Lightweight design of hinge beam based on Kriging agent model

Guizhong Xie,Shixin Zhang,Liangwen Wang,Xiaoyun Gong,Tao Wang,Shuguang Wang,Zhiqiang Chen,Zeheng Zhi 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.7

This paper presents an optimization method based on the Kriging and multiobjective genetic algorithm. First, taking the hinged beam structure of the cubic diamond press as the design object, the optimization design mathematical model was established with the mass as the objective function, the stress and displacement peak as the constraint conditions. Second, in combination with SolidWorks and ANSYS Workbench, parametric modeling analysis was conducted to obtain a large number of sample points sparing less time, and the agent model constructed by Kriging was trained and verified. Finally, taking advantage of global search of the multi-objective genetic algorithm, a lightweight design was realized and the mass of the hinge beam structure was effectively reduced, which would be a guiding significance for the lightweight design of other mechanical parts.

Crushing Characteristics on Square Tubes Under Progressive Buckling

Kaibo Yan,Sisi Lu,Pan Wang,Weitao Ni,Zhaowei Chen,Shuen Zhao,Shuguang Yao 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.1

This paper presented the research on crushing characteristics for progressive bucking square tubes under axial loading using the dimensional analysis method. According to the mechanical properties of mild steel and aluminium alloy, the finite element models of progressive buckling square tubes made up of different materials were established. Then dimensional analysis was developed to obtain the influence of inherent parameters on energy absorption characteristics of progressive buckling square tubes, and a theoretical prediction model was proposed to predict the energy absorption characteristics of progressive buckling square tubes subjected to axial loading. The theoretical prediction results were found to match well with finite element analysis and dynamic test results. Furthermore, the equivalence methods of square tubes made up of different materials and geometric parameters were discussed. The results showed that the equivalence of deformation displacement and equivalence of mean crushing force are better equivalence methods for lightweight design, and keeping a constant length and width to obtain an equivalent thickness for progressive buckling square tubes is a more stable equivalence method.