Experimental Study on Shock Wave Characteristics in Micro Shock Tube

Guang Zhang,YunSang Kim,YingZi Jin,Toxhiaki Setoguchi,HeuyDong Kim 한국가시화정보학회 2015 한국가시화정보학회 학술발표대회 논문집 Vol.2015 No.5

An investigation on the effects of irregular airfoils on the aerodynamic performance of small axial flow fans

Li Zhang,Yingzi Jin,Yu-Zhen Jin 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.6

In this paper, the effects of airfoils on the aerodynamic performance of small axial flow fans were investigated to reduce airflow turbulence on the blade surface and to improve the aerodynamic performance of small axial flow fans. Irregular airfoils where several convex grooves are bound in the blade pressure surface of the fans have two kinds. The wave-shaped edge is bound to the blade trailing edge of the fans and is designed from the smooth airfoil of the fans. The filtered N-S equations with the finite volume method and the standard k-ε turbulence model were adopted to carry out the steady simulation calculation. The large eddy simulation and the FH-W noise models were adopted to carry out the unsteady numerical calculation and aerodynamic noise prediction. The results of simulation calculation are in good agreement with the tests, which proves that the numerical calculation method is feasible. The spectrum characteristics of aerodynamic noise of the smooth airfoil and the two kinds of irregular airfoils were analyzed. Although the fans of the three airfoils are regarded as noise sources, the vortex distribution features in the unsteady flow field are also described. Noise reduction mechanisms of the irregular designs of the airfoils were also discussed. The results of this research may provide proof of the parameter optimization and the structural design of small axial flow fans with low noise.

Study on the Gas-Particle Two-Phase Flows in a Shock Tube

Guang Zhang,Yingzi Jin,Toshiaki Setoguchi,Heuy Dong Kim 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11

Numerical Study on Propagation of Shock Wave in a Micro Shock Tube

Guang Zhang,Yingzi Jin,Toshiaki Setoguchi,Heuy Dong Kim 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.5-2

Study on drug powder acceleration in a micro shock tube

Guang Zhang,Yingzi Jin,Toshiaki Setoguchi,Heuy Dong Kim 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.9

Recently, micro shock tubes have been widely used in the medical engineering. The needle-free drug delivery device which mainly consists of a micro shock tube and an expanded nozzle has been produced to inject drug powders into human and animal bodies without any sharp metal needles. The drug powders were delivered by obtaining high momentum, which can be done by accelerating drug powders in the micro shock tube and supersonic nozzle. The particle-gas flows are induced by the incident shock wave developing by rupturing the diaphragm in the micro shock tube and again accelerated in the supersonic nozzle. The momentum of injected drug particles should be strictly controlled otherwise patients will suffer from skin injury or hurt. Even though micro shock tubes have been investigated in the past several decades, the detailed studies on particle-gas flows in the micro shock tube were rare to date due to the micro size and difficult experimental operation on micro shock tubes. In this paper, the experimental and numerical studies were carried out on investigating particle-gas flows in a designed micro shock tube. Particle tracking velocimetry (PTV) was performed to calculated particle average velocity at the exit of the supersonic nozzle. The nozzle flows were analyzed by obtaining instantaneous particle fields. The particle number density ratio was also investigated in the test section. The numerical simulations were performed by calculating unsteady Naver-Stokes equations on compressible flows and using fully implicit finite volume schemes. Discrete phase model (DPM) was used for simulating particle-gas flows in the micro shock tube. Particle diameter and density were varied to investigate their effects on the particle-gas flows. Unsteady particle-gas flows and shock wave propagation were obtained in details in the micro shock tube for present experimental and numerical studies.

Two-Phase Choked Flows of Gas and Particle in a Convergent-Divergent Nozzle

Guang Zhang,Yingzi Jin,Heuy Dong Kim 한국가시화정보학회 2016 한국가시화정보학회 학술발표대회 논문집 Vol.2016 No.12

Particle-gas two-phase flows show significantly different behaviors compared to single gas flow through convergent-divergent nozzles. Non-equilibrium effects, thermal and velocity lags lead to the inefficiency of nozzle performance. In the present studies, theoretical analysis and numerical simulations were carried out to study particle-gas flows through a C-D nozzle. Homogeneous equilibrium model that no lag in velocity and temperature happen between particles and gas phase was considered to derive choked mass flow rate and sound speed of multiphase flows. Two-phase flows are regarded as isentropic flows that isentropic relations can be used for homogeneous equilibrium model. Discrete phase model (DPM) where interaction with continuous phase and two-way turbulence coupling model were considered was used to simulate particle-gas flows. Particle mass loading (PML) was varied to investigate its effect on choking phenomena for particle-gas flows. Particle volume fraction, specific heat ratio, velocity slip ratio and sound speed of mixture flows were theoretically calculated by homogeneous equilibrium model and compared with numerical results.

Expression of proline-rich protein 15 in breast cancer and its effect on cell biological function

Jiao Tian,Yingzi Zhang,Chi Qu,Han Li,Shengchun Liu 한국고분자학회 2023 Macromolecular Research Vol.31 No.12

PRR15, a member of the proline-rich protein family, has been linked to a better prognosis in breast cancer patients and is highly expressed in a variety of cancer tissues. However, further research must be done on its biological role in breast cancer and its expression. The purpose of this work is to investigate the role of PRR15 in the proliferation, migration, and apoptosis of breast cancer cells as well as to confirm the differential expression of PRR15 in various subtypes of breast cancer tissues and cells. To analyse the differential expression of PRR15 in paracancerous tissues and various types of breast cancer tissues, GEPIA, Kaplan–Meier plotter, GEO, TCGA, and other bioinformatics websites and public databases were used. PRR15 expression in breast cancer tissue was significantly higher than that in normal breast tissue, and PRR15 expression in ER + breast cancer was significantly higher than that in ER- breast cancer. The results were confirmed by RT-PCR, Western Using molecular cloning, plasmids were created to produce cells that over express PRR15. Experiments on how cells behave showed that PRR15 overexpression had no impact on the growth, migration, or death of ER+ and ER− breast cancer cells when compared to control cells. Furthermore, the biological behavior of ER + breast cancer cells was unaffected by PRR15 knockdown.

Design and Implementation of a Novel Horizontal AFM Probe Utilizing a Quartz Tuning Fork

Yifu Chen,Yingzi Li,Guanqiao Shan,Yingxu Zhang,Zhenyu Wang,Mubing Wang,Hua Li,Jianqiang Qian 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.1

This paper presents a new structure of a novel horizontal atomic force microscope probe utilizing a quartz tuning fork. The horizontal structure exhibits high resistance to environmental noise, and thus the probe can maintain good stability throughout the imaging work. The quartz tuning fork, which is utilized as a force sensor due to its simple mechanical structure and self-actuating and self-sensing characteristics, can significantly simplify the mechanical structure of the probe. The probe is divided into three parts: an approximation device, a force sensor, and a three-dimensional scanner. Each part is carefully designed to guarantee the imaging performance. It is verified that the proposed horizontal AFM probe is stable by conducting finite-element analysis, including modal analysis and noise analysis. Furthermore, the probe is fabricated and the experiments are performed to verify its stability. The proposed horizontal AFM probe combined with the existing control system in the frequency modulation succeeds in imaging within 25 μm × 25 μm and 20 μm × 20 μm ranges stably.

Numerical simulation on characteristics of particle-gas flows in supersonic impinging jet

Heuy Dong Kim(김희동),Guang Zhang,Yingzi Jin,Toshiaki Setoguchi 한국가시화정보학회 2016 한국가시화정보학회 학술발표대회 논문집 Vol.2016 No.4

The supersonic impinging jets always occur when crafts are starting short takeoff and vertical landing from the ground. The adverse flow conditions happen to decrease the performance of aircrafts, such as impinging force, high noise spectrum and high shear stresses. Due to rare results on particle-gas impinging jet flows to date, numerical simulations were performed to investigate the supersonic impinging jet flows of particle-gas two phases in the present studies. Convergent-divergent supersonic and convergent sonic nozzles were used to induce the supersonic jet flows. Discrete phase model (DPM) was used to simulate the particle-gas flows. Different particle diameters were investigated. The flow Mach number and pressure coefficients on the ground surface were obtained to describe phenomena inside impinging and wall jet flows. The particle motion was obtained in details from the present simulations.

Long noncoding RNA NEAT1 suppresses hepatocyte proliferation in fulminant hepatic failure through increased recruitment of EZH2 to the LATS2 promoter region and promotion of H3K27me3 methylation

Qiang Wang,Lian Liu,Sheng Zhang,Yingzi Ming,Shu Liu,Ke Cheng,Yujun Zhao 생화학분자생물학회 2020 Experimental and molecular medicine Vol.52 No.-

Fulminant hepatic failure (FHF) refers to the rapid development of severe acute liver injury with impaired synthetic function and encephalopathy in people with normal liver or well-compensated liver disease. This study aimed to investigate the function of long noncoding RNA (lncRNA) nuclear-enriched abundant transcript 1 (NEAT1) on the proliferation and apoptosis of hepatocytes in FHF. Our results revealed that lncRNA NEAT1 was upregulated in cell and animal models of FHF induced by D-galactosamine (D-GalN)/lipopolysaccharide (LPS). Overexpression of lncRNA NEAT1 resulted in elevated hepatocyte apoptosis and impaired large tumor-suppressor kinase 2 (LATS2) expression and proliferation. Functional analysis revealed that knockdown of lncRNA NEAT1 inhibited hepatocyte apoptosis and induced proliferation both in vitro and in vivo. RNA immunoprecipitation and chromatin immunoprecipitation assays demonstrated that lncRNA NEAT1 recruited enhancer of zeste homolog 2 (EZH2) to the LATS2 promoter and repressed LATS2 expression. Furthermore, ectopic expression of LATS2 increased proliferation and inhibited hepatocyte apoptosis by regulating the Hippo/Yes-associated protein (YAP) signaling pathway. Taken together, our findings indicate that lncRNA NEAT1 might serve as a novel target for FHF therapy due to its regulation of H3K27me3 methylation-dependent promotion of LATS2.