Cloning and Characterization of the IgA Fc Receptor from Swine

( Yumei Chen ),( Yunchao Liu ),( Gaiping Zhang ),( Hua Feng ),( Pengchao Ji ),( Guoqiang Wang ),( Chang Liu ),( Yapeng Song ),( Yunfang Su ),( Songlin Qiao ),( Aiping Wang ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.12

The myeloid-specific IgA Fc receptor (FcαR) is a cell surface molecule on immunocytes that provides a fundamental connection between humoral and cellular immunity. In this study, the full-length cDNA sequence of swine FcαRI (swFcαRI) was isolated and characterized and found to contain a 792-base-pair open reading frame, encoding a 264-amino-acid transmembrane glycoprotein with a predicted molecular mass of 29.4 kDa. The swFcαRI shares high amino acid sequence homology (>50%) with its counterparts from cattle, seal, and horse. Rosetting analysis confirmed that COS-7 cells transfected with an swFcαRI expression plasmid was able to combine with chicken erythrocytes sensitized with porcine IgA, but not IgG.

Model Predictive Control-based Trajectory Planning for Quadrotors with State and Input Constraints

Penghong Lin,Songlin Chen,Chang Liu 제어로봇시스템학회 2016 제어로봇시스템학회 국제학술대회 논문집 Vol.2016 No.10

A novel scheme to solve the trajectory planning problem for quadrotors with model and state constraints is proposed. First the RRT (Rapidly-exploring Random Tree) algorithm is employed to generate an initial route in context of a 3D environment. Then with the model of quadrotoer, the MPC (Model Predictive Control) method is used to construct an inner simulator which can generate the trajectories satisfying the state constraints by following the waypoints exported by the RRT solution. Finally, the trajectory generation of quadrotors with state and input constraints is transformed into a general form of QP problem, which can be solved expediently by common numerical algorithms. The proposed scheme can generates high-quality and feasible trajectories satisfying both state constraints and input constraints, which is verified sufficiently by extensive simulations.

Modeling of Friction Torque Based on Turntable Servo System Using Neural Network with Memory Storage Unit

Cheng Xie,Songlin Chen,Yang Liu 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.7

Friction is the main factor affecting the performance of the servo systems. The tracking accuracy can be effectively improved by compensating the rotational torque online with the accurate value of friction torque. Therefore, it is necessary to build a friction model, which can accurately describe the friction characteristics of the servo systems during operation. This paper proposes a neural network model based on the mechanical characteristics of friction. The memory storage unit is added to the network structure to store the state information between the current and the next speed reversal time so as to process the dynamic and static friction characteristics separately. To eliminate the quantization noise existing in the angular velocity calculated by the angular position difference, the Savitzky-Golay convolution smoothing algorithm is used to smooth the angular velocity and the genetic algorithm is used to determine the sliding window size and the fitting polynomial order. The simulation results show that the neural network model proposed in this paper can reproduce the characteristics of the dynamic and static friction torque well, and the fitting effect is better than that of the feedforward network and LuGre model under different forms of excitation signals, so it has strong generalization ability and predictive accuracy. In addition, the modeling process can be effectively simplified, thus verifying the effectiveness and superiority of the proposed method.

The effect of the sintering temperature on the properties of porous YAG ceramics

Jieguang Song,Lin Chen,Cailiang Pang,Jia Zhang,Weiguo Shi,Songlin Guo,Xianzhong Wang,Minghan Xub 한양대학교 세라믹연구소 2018 Journal of Ceramic Processing Research Vol.19 No.1

Pure yttrium aluminum garnet (YAG) powders and the porous YAG ceramics were prepared via co-precipitation method andusing vacuum sintering technology, respectively. Through an analysis and discussion, porous YAG ceramics, with ahomogeneous and regular pore microstructure, a pore size of about 5 μm, regular crystalline particles, showing intergranularfracture, were sintered at 1500 oC. Porous YAG ceramics, with a homogeneous and regular pore microstructure, a pore sizefor about 2-5 μm, crystals with a rod-shape or acicular structure, showing intergranular fracture and intracrystalline fracture,were sintered at 1550 oC. Porous YAG ceramics, with an extension pore microstructure, a crystalline laminate structure,showing intracrystalline fracture, were sintered at 1600 oC. With an increase in the sintering temperature, the porosity isdecreased gradually and the energy consumption is increased. The best sintering temperature for porous YAG ceramics wasdecided to be 1550 oC through considering the performance price ratio among the porosity, the mechanical properties and theenergy consumption.

Colloidal nano-abrasives and slurry for chemical-mechanical polishing of semiconductor materials

Kailiang Zhang,Zhitang Song,Chenglu Lin,Songlin Feng,Bomy Chen 한양대학교 세라믹연구소 2007 Journal of Ceramic Processing Research Vol.8 No.1

Chemical-mechanical polishing or planarization (CMP) is one of the key fabrication processes in the semiconductor industry. Colloidal nano-abrasives with different particle sizes are required for slurries in different CMP processes of semiconductor. So the controlled-growth of particle sizes, particle size distribution and their application become more and more important. In this paper, based on additional experiments and analysis, colloidal nano-abrasives with different particle sizes were prepared by ion-exchange and hydrothermal processes, and their size and stability were characterized by transmission electron microscope (TEM) and a Zeta potential instrument. Results show that colloidal nano-abrasives with diameters of 10-20 nm, 50-70 nm, 80-90 nm were obtained, and the zeta potential (less than −45 mV) also illustrates that the colloidal nano-abrasives was of high stability. One kind of colloidal nano-abrasives with average diameter of 80-90 nm was used to prepare one polishing slurry for silicon wafers. The polishing rate was more than 600 nm/minute and the root mean square (RMS) of surface roughness for polished silicon wafers was less than 0.4 nm, which shows that this type of slurry with the self-made colloidal abrasives not only gives higher polishing rate, but also provides less surface roughness. Chemical-mechanical polishing or planarization (CMP) is one of the key fabrication processes in the semiconductor industry. Colloidal nano-abrasives with different particle sizes are required for slurries in different CMP processes of semiconductor. So the controlled-growth of particle sizes, particle size distribution and their application become more and more important. In this paper, based on additional experiments and analysis, colloidal nano-abrasives with different particle sizes were prepared by ion-exchange and hydrothermal processes, and their size and stability were characterized by transmission electron microscope (TEM) and a Zeta potential instrument. Results show that colloidal nano-abrasives with diameters of 10-20 nm, 50-70 nm, 80-90 nm were obtained, and the zeta potential (less than −45 mV) also illustrates that the colloidal nano-abrasives was of high stability. One kind of colloidal nano-abrasives with average diameter of 80-90 nm was used to prepare one polishing slurry for silicon wafers. The polishing rate was more than 600 nm/minute and the root mean square (RMS) of surface roughness for polished silicon wafers was less than 0.4 nm, which shows that this type of slurry with the self-made colloidal abrasives not only gives higher polishing rate, but also provides less surface roughness.

Preparation and properties of Al-Al2O3 metal ceramics via powder metallurgy methods

Jieguang Song,Xiuqin Wang,Lin Chen,Cailiang Pang,Jia Zhang,Weiguo Shi,Songlin Guo,Xianzhong Wang,Ruihua Wang 한양대학교 세라믹연구소 2018 Journal of Ceramic Processing Research Vol.19 No.1

Metal ceramics are outstanding new engineering materials that offer the advantages of both ceramics and metals. In this study,Al-Al2O3 metal ceramics were prepared through powder metallurgy methods, and the densification and properties of theprepared metal ceramics were investigated to gain insights into the preparation of high-performance cermet materials. Resultsrevealed that as the forming pressure was increased, the relative density of the ceramics increased, whereas their electricalresistivity decreased. The relative density increased with increasing sintering temperature up to 700 oC and decreased beyond700 oC, whereas the electrical resistivity exhibited an opposite trend. The relative density increased with increasing Al content,whereas the electrical resistivity displayed an opposite trend. Under optimal technological parameters of 700 oC sinteringtemperature, < 20MPa forming pressure, and 75 wt% Al content, Al-Al2O3 metal ceramics with a high relative density(97.52%) and a low electrical resistivity (101.34 Ω·m) were successfully prepared.

The linear elastic stiffness matrix model analysis of pre twisted Euler Bernoulli beam

Ying Huang,Haoran Zou,Chang Hong Chen,Songlin Bai,Yao Yao,Leon M. Keer 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.72 No.5

Based on the finite element method of traditional straight Euler-Bernoulli beams and the coupled relations between linear displacement and angular displacement of a pre-twisted Euler-Bernoulli beam, the shape functions and stiffness matrix are deduced. Firstly, the stiffness of pre-twisted Euler-Bernoulli beam is developed based on the traditional straight Euler-Bernoulli beam. Then, a new finite element model is proposed based on the displacement general solution of a pre-twisted Euler-Bernoulli beam. Finally, comparison analyses are made among the proposed Euler-Bernoulli model, the new numerical model based on displacement general solution and the ANSYS solution by Beam188 element based on infinite approach. The results show that developed numerical models are available for the pre-twisted Euler-Bernoulli beam, and which provide more accurate finite element model for the numerical analysis. The effects of pre-twisted angle and flexural stiffness ratio on the mechanical property are investigated.

Sintering densification and properties of Al2O3/Al cermet materials via powder metallurgy method

Jieguang Song,Yue Liu,Cailiang Pang,Jia Zhang,Lin Chen,Xiling Zhang,Songlin Guo,Xianzhong Wang,Ruihua Wang,Aixia Chen 한양대학교 세라믹연구소 2018 Journal of Ceramic Processing Research Vol.19 No.2

Cermet materials are important new engineering materials with combined advantages of ceramics and metals. In this study,Al2O3/Al cermet materials were prepared through powder metallurgy. The effect of sintering technology on the properties ofAl2O3/Al cermet materials was analyzed as basis for preparing high-performance cermet materials. Results showed that whenthe sintering temperature was increased from 700 oC to 1000 oC under holding time for 1 h, the densification degree and hardnessof Al2O3/Al cermet materials decreased and the electric resistivity increased. In the microstructure of Al2O3/Al cermet materials,Al particles were larger and continuously distributed, whereas the Al2O3 particles were smaller and discontinuously distributed. When the holding time was increased under sintering temperature of 700 oC, the densification degree and hardness of Al2O3/Alcermet materials also increased, and the electric resistivity decreased. When 25 wt% Al2O3/Al cermet materials were sintered at700 oC for 3 h, the densification degree was higher, with hardness of 2203 HV and electric resistivity of 0.0159 Ω • m.