Development and Validation of a Low-Cost and Simple Simulator for Microlaryngeal Surgery

Pengcheng Yu,Jia Luan,Xidong Cui,Xumao Li,Xinqi Hu,Guangbin Sun 대한이비인후과학회 2020 Clinical and Experimental Otorhinolaryngology Vol.13 No.1

Objectives. The simulation of microlaryngeal skills is rarely seen in surgical training, but it is particularly important in phonomicrosurgery. This study described and validated the laryngeal surgical simulator through surgical training. Methods. A simple and low-cost simulator was developed for the fixation of the suspension laryngoscope and porcine larynges. Twenty participants with work skills and experience did preparation before training, and performed suture and carbon dioxide (CO2) laser cordectomy for simulator evaluation. The results were proposed by the aspects of time taken for each procedure, the global rating scale, a procedure-specific assessment, and a post-simulation questionnaire. Results. All participants completed the preparation within 9 minutes and reached the conclusion that the microlaryngeal surgical simulator was helpful in improving their surgical skills. The performance of experts was superior to that of novices in both suture and CO2 laser cordectomy. Conclusion. This simulator could be easily assembled and was successfully validated by microlaryngeal surgical training both subjectively and objectively. It may be helpful to clinicians in microlaryngeal skills.

Numerical Investigation on a Twin-Screw Multiphase Pump Under low IGVF

Shuaihui Sun,Pengbo Wu,Pengcheng Guo,Guangzhi Yi,Ahmed Kovacevic 한국유체기계학회 2021 International journal of fluid machinery and syste Vol.14 No.4

A three-dimensional transient numerical model was developed to obtain the two-phase flow characteristics in a twin-screw multiphase pump based on dynamic mesh technology and the multiphase flow model. The pump performance under different inlet gas volume fractions (IGVF) was predicted by the numerical model and was tested. Then, the numerical model was validated after comparing the simulation and experimental results. After that, the flow field in the pump under 10% IGVF was analyzed. When the IGVF is 10%, the pressure increases step by step and is symmetrical from both ends to the middle of the screw rotors. The pressure distribution through a single working chamber is uniform. It falls rapidly at the inlet of the tooth tip gap and then drops linearly in the gap channel. At the outlet of the tip gap, the pressure temporarily falls due to the high-speed jet. The GVF distribution in the working chamber is uneven. The leakage flow is laminar in the tip gap, and the liquid concentrates on the top of the gap. When the last working chamber connects with the discharge chamber, the discharge jet flow causes the vortices in the discharge pipe. The gas gradually moves to the center of the vortices, forming four gas-phase aggregation regions. The velocity of the interlobe leakage is the largest. The maximum velocity appears at the second cross-section and reaches 35m/s. This research can be used to improve the performance of the twin-screw multiphase pump under two-phase working conditions.

Chemerin reverses the malignant phenotype and induces differentiation of human hepatoma SMMC7721 cells

Ming Li,Pengcheng Sun,Kaikai Dong,Ye Xin,Aslee TaiLulu,Qinyu Li,Jing Sun,Min Peng,Ping Shi 대한약학회 2021 Archives of Pharmacal Research Vol.44 No.2

Chemerin exhibits an inhibitory eff ect on hepatocellularcarcinoma; however, the underlying mechanismis unclear. Here, low chemerin expression was confi rmedin samples of liver cancer patients and hepatoma cells. Chemerin altered hepatoma cell morphology but had noeff ect on normal hepatocytes. Chemerin inhibited proliferationof several human hepatoma cell lines. Real-time PCRdetection of hepatocellular carcinoma markers showed thatmRNA levels of albumin and A-type gamma-glutamyltransferase increased whereas those of alpha-fetoprotein,alkaline phosphatase, B-type gamma-glutamyl transferase,insulin-like growth factor II, and human telomerase reversetranscriptase decreased in chemerin-treated SMMC7721cells. Western blotting revealed that chemerin up-regulatedalbumin and vimentin expressions, and downregulated alpha-fetoprotein expression. Phosphorylated STAT3 wassignifi cantly up-regulated, whereas phosphorylated ERKand AKT were signifi cantly downregulated by chemerin. Chemerin decreased phosphorylated ERK and AKT expressionand the cell proliferation induced by PI3K activator 740Y-P but could not signifi cantly alter phosphorylated STAT3expression and the cell growth induced by STAT3 inhibitorNSC74859. In conclusion, chemerin reversed the malignantphenotype and induced SMMC7721 cell diff erentiation byinhibiting MAPK/ERK and PI3K/AKT signaling; growthinhibition by chemerin is not directly related to the JAK/STAT signaling pathway. Our study provides novel evidencethat chemerin could be utilized for liver cancer treatment.

Improved Mechanical Properties of Friction Stir Welded 1500 MPa Martensitic Steel Joints with Additional Water Cooling

Shuhao Zhu,Pengcheng Zhu,Binbin Wang,Liang Zhang,Yufeng Sun,Shaokang Guan 대한금속·재료학회 2024 METALS AND MATERIALS International Vol.30 No.1

This study proposes a method to improve the mechanical strength of martensitic welded joints by minimizing the effect ofmartensitic tempering. The high-strength martensitic steel plate exhibiting a tensile strength of 1500 MPa was successfullyjoined in this study utilizing additional water-cooling by friction stir welding (FSW) technique. Concurrently, conventionalair-cooled welded joints were produced utilizing identical welding parameters for comparison. Notwithstanding the macrostructureof both FSW joints was similar, the air-cooled joint contained a larger stir zone (SZ) and wider heat-affectedzone (HAZ). The air-cooled joint SZ exhibited a microstructure featuring coarse martensite, while the water-cooled jointSZ displayed a microstructure consisting of fine martensite. The degree of self-tempering of the martensite in the HAZ wassignificantly reduced, together with fewer and finer carbide particles than in the HAZ of air-cooled joints, by applying watercooling. The tensile test results indicated that the water-cooled FSW joint showed a significant improvement (23.6%) inultimate tensile strength compared to its air-cooled counterparts.

Neutronics analysis of JSI TRIGA Mark II reactor benchmark experiments with SuperMC3.3

Wanbin Tan,Pengcheng Long,Guangyao Sun,Jun Zou,Lijuan Hao 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.7

Jozef Stefan Institute (JSI), TRIGA Mark II reactor employs the homogeneous mixture of uranium and zirconium hydride fuel type. Since its upgrade, a series of fresh fuel steady state experimental benchmarks have been conducted. The benchmark results have provided data for testing computational neutronics codes which are important for reactor design and safety analysis. In this work, we investigated the JSI TRIGA Mark II reactor neutronics characteristics: the effective multiplication factor and two safety parameters, namely the control rod worth and the fuel temperature reactivity coefficient using SuperMC. The modeling and real-time cross section generation methods of SuperMC were evaluated in the investigation. The calculation analysis indicated the following: the effective multiplication factor was influenced by the different cross section data libraries; the control rod worth evaluation was better with Monte Carlo codes; the experimental fuel temperature reactivity coefficient was smaller than calculated results due to change in water temperature. All the results were in good agreement with the experimental values. Hence, SuperMC could be used for the designing and benchmarking of other TRIGA Mark II reactors.

Optimal disc cutters plane layout design of the full-face rock tunnel boring machine (tbm) based on a multi-objective genetic algorithm

Junzhou Huo,Wei Sun,Jing Chen,Pengcheng Su,Liying Deng 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.2

Improving of the quality of the disc cutters’ plane layout design of the full-face rock tunnel boring machine (TBM) is the most effective way to improve the global performance of a TBM. The plane layout design of disc cutters contains multiple complex engineering technical requirements and belongs to a multi-objective optimization problem with multiple nonlinear constraints. Based on analysis of the technical requirements of the plane layout problem, an optimizing mathematical model was built. To obtain a set of design schemes for engineers to choose from, a multi-objective genetic algorithm (MOGA) was applied to carry out the optimization of the mathematical model. A constraint-domination principle was utilized to handle the constraints, and a nondominated sorting method was adopted to obtain Pareto solutions. Simulation results showed that the proposed method was efficient and accurate in obtaining the Pareto layout solutions.

Numerical Analysis of Two-Phase Flow in a Micro-Hydraulic Turbine

Tiejun Chen,Shuaihui Sun,Ye Pang,Pengcheng Guo 한국유체기계학회 2019 International journal of fluid machinery and syste Vol.12 No.4

In many industrial processes such as natural gas processing, seawater desalination et al, there is a large amount of liquid waste pressure energy, which can be converted into electric or mechanical energy by a micro-hydraulic turbine. But its efficiency and stability will deteriorate when the working fluid contains gas. Aiming at improving the hydraulic efficiency of the micro-turbine, the three-dimensional transient two-phase flow model which adopts the shear-stress-transport (SST) model as turbulence model and Eulerian-Eulerian model as two-phase flow model with the commercial code ANSYS-CFX was established and solved to study the two-phase flow characteristics of the micro-hydraulic turbine with fixed guide vane openings under different gas volume fraction (GVF). The numerical simulation results show that the power and efficiency of the turbine decrease by 24% and 21% respectively when the inlet GVF is 0.20. The area of low pressure in each impeller passage increases with the inlet GVF, and the pressure difference between the working and suction surface of the blade decreases. The GVF distribution in impeller passage is asymmetrical, which is caused by the gas-liquid separation in the volute. At the left lower part of impeller passage, the gas accumulates at the suction surface of the blades under the Coriolis force and its GVF reaches 90%. The asymmetrical GVF distribution will result in the asymmetrical pressure distribution in the impeller passage, which leads to the imbalance force on the blades. Moreover, the asymmetrical GVF distribution will reinforce the positive incidence at the lower part of impeller passage, and weaken it at the upper right impeller passage. The volute should be redesigned to ensure the uniform gas distribution at the inlet of each impeller passage.

An Improved B-Spline Fitting Method with Arc-Length Parameterization, G2-Continuous Blending, and Quality Refinement

Kang Min,Yanyan Sun,Chen-Han Lee,Pengcheng Hu,Shanshan He 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.11

In computer numerical control machining, tool paths are typically represented with piecewise linear segments (GO1s), which lack G1 and G2 continuity and cause fluctuation of feed rate and acceleration. To improve the continuity of tool paths, some method, e.g., B-spline tool path fitting, is preferred. However, none of the currently B-spline fitting method satisfies all tool-path fitting requirements of arc-length parameterization, G2 continuity and smoothness across the whole path. The aim of this research is to derive an industrial-strength method for B-spline tool path fitting, satisfying all of the named requirements. The improvements cover the arc-length based parameterization, G2 continuity as well as numerically measure to improve the quality of B-spline tool paths. To achieve arc-length parameterization, a preliminary fitting is added to evaluate arc-length and guide the parameterization (i.e., knot vector assignment); for joint G2-continuity, a five-control-point B-spline which satisfies chord error and shape-preserving constraints is constructed to blend adjacent B-splines; and a method based on the Hausdorff distance between the fitted B-splines and the original polylines is used to evaluate the fitting quality, and an additional refinement procedure is employed when the evaluation finds any disqualification. Simulation and experiment results prove that the proposed methods are effective.

Simplified topology optimization of damping layer in plate structures for vibration and acoustic response

Le Qi,Quanwei Cui,Cheng Wang,Xueyan Sun,Janxing Zhou,Pengcheng Jin,Guochun Liu,Lirui Song 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.12

In this paper, a simplified acoustic optimization method is proposed to replace the sound power with the maximum normal velocity of the surface as a direct target, a topological optimization model of the variable density method is established to reduce the acoustic radiation of the structure, and the relationship between the form of damping distribution and the acoustic radiation is investigated. The complex modulus model is used to describe the viscoelastic material intrinsic relationship of the damping layer. The effects of different excitation frequencies on the topology optimization results are discussed. The radiated noise is simulated using the finite element method and the boundary element method. Five plates are fabricated according to the damping layer layout for different single-frequency excitations. Modal and acoustic experiments are carried out to validate the proposed method. The numerical and experimental results show that there is a significant reduction in the sound pressure level (SPL).

Performance improvement prediction of push chain moist-mix concrete spraying machine employing orifice plate

Lianjun Chen,Hui Ma,Guanguo Ma,Gang Pan,Pengcheng Li,Zhenjiao Sun 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.6

Push chain moist-mix concrete spraying machine is widely used in shotcrete construction processes, but shotcrete surplus has always been the main problem affecting work efficiency. To improve the efficiency, the orifice plate is employed in the discharge cylinder, considering three different distributions (equal, left concentrated and both side distribution) of the holes and two hole diameters (6 mm and 8 mm). In different orifice plate, the discharge cylinder flow field is studied employing the FLUENT software by the computational fluid dynamic method. Besides, dimensionless evaluation index of the discharge cylinder flow field is defined based on the force of particles. By comparing dimensionless index and velocity vector, the best orifice plate (both side distribution and 8 mm) is presented. Compared without orifice plate, the experiment showed the shotcrete surplus ability is reduced by 26 %-87 %. This study provides guidance for the design and optimization of pneumatic conveying equipment.