Stability/instability of the graphene reinforced nano-sized shell employing modified couple stress model

Zhigang Yao,Hui Xie,Yulei Wang 한국풍공학회 2021 Wind and Structures, An International Journal (WAS Vol.32 No.1

The current research deals with, stability/instability and cylindrical composite nano-scaled shell’s resonance frequency filled by graphene nanoplatelets (GPLs) under various thermal conditions (linear and nonlinear thermal loadings). The piece-wise GPL-reinforced composites’ material properties change through the orientation of cylindrical nano-sized shell’s thickness as the temperature changes. Moreover, in order to model all layers’ efficient material properties, nanomechanical model of Halpin-Tsai has been applied. A functionally modified couple stress model (FMCS) has been employed to simulate GPLRC nano-sized shell’s size dependency. It is firstly investigated that reaching the relative frequency’s percentage to 30% would lead to thermal buckling. The current study’s originality is in considering the multifarious influences of GPLRC and thermal loading along with FMCS on GPLRC nano-scaled shell’s resonance frequencies, relative frequency, dynamic deflection, and thermal buckling. Furthermore, Hamilton’s principle is applied to achieve boundary conditions (BCs) and governing motion equations, while the mentioned equations are solved using an analytical approach. The outcomes reveal that a range of distributions in temperature and other mechanical and configurational characteristics have an essential contribution in GPLRC cylindrical nano-scaled shell’s relative frequency change, resonance frequency, stability/instability, and dynamic deflection. The current study’s outcomes are practical assumptions for materials science designing, nano-mechanical, and micro-mechanical systems such as micro-sized sensors and actuators.

Cloning and Characterization of Ribosome-associated Membrane Protein 4 (RAMP4) gene in silkworm Bombyx mori

Yao Qin,Hu Zhigang,Xu Jiaping,Chen Keping Korean Society of Sericultural Science 2005 International Journal of Industrial Entomology Vol.10 No.2

Ribosome-associated membrane protein 4 (RAMP4) is a membrane protein that exposes its N-terminal hydrophilic portion on the cytoplasmic side and spans the membrane close to the C-terminal end. RAMP4 has previously been reported to belong to the set of proteins that remains associated with membrane-bound ribosomes, and controls the glycosylation of major histocompatbility complex class II-associated invariant chain. RAMP4 also may be relative to the stabilization of membrane proteins in response to stress, with other components of translocon, and molecular chaperons in ER. Application of 5'-RACE technique with specially designed primer, we cloned a 715 bp cDNA fragment which contains a 195 bp ORF, termed RAMP4. The deduced protein has 64 amino acid residues and contains a putative transmembrane-spanning domain at the COOH terminus.

RNA Interference to Prevent Bombyx mori Nuclear Polyhedrosis Virus Infection in Vivo

Hu Zhigang,Chen Keping,Gao Lu,Yao Qin Korean Society of Sericultural Science 2006 International Journal of Industrial Entomology Vol.12 No.1

RNA interference has been used as a powerful tool in preventing virus proliferation in many species. In this study, we injected the dsRNA in vitro transcripts into Bombyx mori to investigate the resistance to B. mori nuclear polyhedrosis virus (BmNPV). Through vivisectional observation and real-time quantities PCR analysis, we found that these dsRNA can prevent the BmNPV to a certain extent, and delay the viruses' proliferation.

Liner Behavior of a Tunnel Constructed Below a Caved Zone

Yongfang Jia,Zhigang Yao,Gabriel Walton,Yapeng Fu 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.10

Underground mining leads to deformation of the surrounding rock strata. Over time, this deformation tends to stabilize after mining has completed. However, ground movement can easily reactivated if another adjacent underground project is excavated nearby. When tunnelling underneath caved mining areas, the associated effects on load distribution and liner behavior of this caved zone can be significant. This paper presents a series of scale model tests to understand these effects. In these tests, various testing material compositions were used to simulate intact rocks, a caved zone, primary support and secondary liner based on similarity theory. Various caved zone-tunnel distances (d) and different buried depths were considered in the tests. Results such as deformation, thrust force and bending moment of the liner were recorded and compared. The results show that the caved zone has an obvious impact on the liner when it is located above and nearby the tunnel, but this influence decreases rapidly as a function of d. If the caved zone-tunnel distance is between 50% and 100% of the tunnel span, the bearing capability of the rock immediately surrounding the excavation is significantly reduced, which leads to more vertical load on the support of the tunnel compared to a tunnel without a caved zone. Furthermore, as the shape of broken rock is irregular and the arrangement is random, the caved zone creates an asymmetrical distribution of displacements if the tunnel is near the caved zone. Additionally, this may result in large moments and damage at the tunnel crown.

Constraints on Biotic and Abiotic Role in the Formation of Fe-Si Oxides from the PACMANUS Hydrothermal Field

Yang Baoju,Zeng Zhigang,Qi Haiyan,Wang Xiaoyuan,Ma Yao,Rong Kunbo 한국해양과학기술원 2015 Ocean science journal Vol.50 No.4

Fe-Si oxide deposits were recovered from the PACMANUS (Papua New Guinea-Australia-Canada-Manus) hydrothermal field in Eastern Manus basin. Samples were loose and fragile. Optical and scanning electron microscopy showed that the samples had abundant rod-like or twisted filamentous and granular structures. Electron probe microanalysis revealed that these filaments and grains were mainly composed of Fe and Si. The presence of spherical grains on the surface of the filaments suggests the intergrowth of biotic and abiotic reactions. Biotic and abiotic kinetics competition always exists in the redox gradient. Based on the physico-chemical conditions of PACMANUS hydrothermal fluids, we calculated a strict abiotic oxidation rate of Fe2+ to Fe3+, which is approximately 0.0123 g/min. If the fluids had been erupting consistently and the concentration of Fe2+ was constant, 3.232 kg per year of Fe would be deposited in this vent. The amount of Fe oxides around the studied vent was larger than the amount determined by strict abiotic kinetic calculation. Bacteria may also play an important role in Fe oxidation. A mesh-like microenvironment constructed by biogenic filaments ensured adequate Fe2+ and low oxygen content for the growth of bacteria. Moreover, this structure promoted the deposition of abiotic Fe-Si oxides.

A Modeling Study of the Characteristics and Mechanism of the Westward Coastal Current during Summer in the Northwestern South China Sea

Yang Ding,Xianwen Bao,Zhigang Yao,Cong Zhang,Kai Wan,Min Bao,Ruixiang Li,Maochong Shi 한국해양과학기술원 2017 Ocean science journal Vol.52 No.1

The characteristics and dynamical mechanism of summer-time coastal current over the North South China Sea shelf have been investigated based on a high resolution unstructuredgrid finite volume community ocean model (FVCOM). Modeldata comparison demonstrates that the model describes and explains well the coastal dynamics over the North South China Sea shelf. The coastal current on the North South China Sea shelf is greatly influenced by monsoon and the freshwater discharge of the Pearl River. Strong southwesterly wind drives the coastal current northeastward. However, under weak southwest monsoon, the coastal current west of the Pearl River estuary (PRE) advects toward the southwest, and splits into two parts when reaching east of the Qiongzhou Strait, with one branch entering the Gulf of Tonkin through the Qiongzhou Strait, transporting low salinity water into the Gulf of Tonkin, and the other part flows cyclonic and interacts with the northeastward current around southeast of Hainan Island, forming a cyclonic eddy east of the Qiongzhou Strait. A variety of model experiments focused on freshwater discharge, wind forcing, tidal rectification, and stratification are performed to study the physical mechanism of the southwestward coastal current which is usually against the summer wind. Process-oriented experiment results indicate that the southwest monsoon and freshwater discharge are important factors influencing the formation of southwestward coastal current during summer.

Surface Settlement Prediction for EPB Shield Tunneling in Sandy Ground

Yongfang Jia,Chuan He,Ali Nazem,Zhigang Yao,Jacob Grasmick 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.7

Ground volume loss induced by shield tunnel construction is the major factor leading to ground settlement and deformation. The general equations predicting surface settlement based on ground volume loss involve a settlement trough width coefficient (parameter i) which in previous models was set as a constant in both the transverse and longitudinal directions. In this work, the equations predicting surface settlement during the construction were modified by introducing the parameter j – the width coefficient in the longitudinal direction, assumed to be different from that in the transverse direction. A model shield machine was adopted to carry a laboratory test under 1 g to investigate surface settlement induced by earth-pressure-balance shield tunnel construction in unsaturated sandy soil. The surface settlement during the excavating observed in the test was compared with that predicted by general equations from previous studies and the modified. The results showed that surface settlement above shield machine obtained by the modified equation proposed here fits the test data better than those obtained by the general equations because of the introduced longitudinal width coefficient.

The Real Time Infrared Image Acquisition and Processing System Design Based on FPGA

Fan Jianying,Cui Xin,Fan Zhigang,Feng Yao 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.2

Field programmable gate array (FPGA) has the characteristics of high speed, low power consumption, high integration, flexibility and, small size, etc. In this paper, I design a real time infrared image processing and display system based on FPGA for the requirement of real time infrared image processing, which will realize the transmission, transformation, and storage of the image information, and then complete the infrared image edge detection based on Sobel algorithm by using this system as a platform. At last, the advantages of infrared image processing with this system compared with other methods will be verified in this paper. The experimental results show that the system spends 11.44ms on processing the colorful image whose resolution is 640480.The system has realized the real time, high speed, stable and reliable acquisition, processing and display of infrared image and we can realize the infrared target feature extraction, recognition and tracking when we combine the system with other algorithms.

Important Role of Immunological Responses to Environmental Exposure in the Development of Allergic Asthma

Xinliu Lin,Xia Ren,Xiaojun Xiao,Zhaowei Yang,Siyang Yao,Gary WK Wong,Zhigang Liu,Charles Wang,Zhong Su,Jing Li 대한천식알레르기학회 2020 Allergy, Asthma & Immunology Research Vol.12 No.6

Allergic asthma is a public health problem that affects human health and socioeconomic development. Studies have found that the prevalence of asthma has significantly increased in recent years, which has become particularly pronounced in developed countries. With rapid urbanization in China in the last 3 decades, the prevalence of asthma has increased significantly in urban areas. As changes in genetic backgrounds of human populations are limited, environmental exposure may be a major factor that is responsible for the increased prevalence of asthma. This review focuses on environmental components of farms and rural areas that may have protective effects in reducing the development of asthma. Farm and rural related microorganism- and pathogen-associated molecular patterns are considered to be important environmental factors that modulate host's innate and adaptive immune system to induce protection effects later in life. Environmental microbial-related immunotherapy will also be discussed as the future research direction for the prevention of allergic asthma.

Design and optimization of novel transceiver device for one‑way single‑wire power transfer

Yang Li,Taocheng Hu,Xueliang Wang,Yujie Zhai,Yao Li,Wenxin Huang,Zhigang Lou 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.10

The further development of wireless power transfer technology is hindered by the limiting relationship between transmission distance, transmission efficiency, and size of the coupling mechanism. Thus, a feasible solution was provided by one-way single-wire power transfer. First, a horn-type mode conversion device was proposed in this study by analyzing the principle of one-way single-wire power transfer. Second, the system structure was designed to save materials and reduce the volume of space. The transmission efficiency of the system was improved, and the operating frequency was reduced by optimizing the parameters of the mode conversion device. Finally, the feasibility and structural applicability of the one-way single-wire power transfer method proposed in this study were proved by the experimental results.