Analysis of Factors Impacting Atmospheric Pressure Plasma Polishing

Ju-Fan Zhang,Bo Wang,Shen Dong 한국정밀공학회 2008 International Journal of Precision Engineering and Vol.9 No.2

Atmospheric pressure plasma polishing (APPP) is a noncontact precision machining technology that uses low temperature plasma chemical reactions to perform atom-scale material removal. APPP is a complicated process, which is affected by many factors. Through a preliminary theoretical analysis and simulation, we confirmed that some of the key factors are the radio frequency (RF) power, the working distance, and the gas ratio. We studied the influence of the RF power and gas ratio on the removal rate using atomic emission spectroscopy, and determined the removal profiles in actual operation using a commercial form talysurf. The experimental results agreed closely with the theoretical simulations and confirmed the effect of the working distance. Finally, we determined the element compositions of the machined surfaces under different gas ratios using X-ray photoelectron spectroscopy to study the influence of the gas ratio in more detail. We achieved a surface roughness of Ra 0.6 ㎚ on silicon wafers with a peak removal rate of approximately 32 ㎣/min.

Analysis of Factors Impacting Atmospheric Pressure Plasma Polishing

Zhang, Ju-Fan,Wang, Bo,Dong, Shen Korean Society for Precision Engineering 2008 International Journal of Precision Engineering and Vol.9 No.2

Atmospheric pressure plasma polishing (APPP) is a noncontact precision machining technology that uses low temperature plasma chemical reactions to perform atom-scale material removal. APPP is a complicated process, which is affected by many factors. Through a preliminary theoretical analysis and simulation, we confirmed that some of the key factors are the radio frequency (RF) power, the working distance, and the gas ratio. We studied the influence of the RF power and gas ratio on the removal rate using atomic emission spectroscopy, and determined the removal profiles in actual operation using a commercial form talysurf. The experimental results agreed closely with the theoretical simulations and confirmed the effect of the working distance. Finally, we determined the element compositions of the machined surfaces under different gas ratios using X-ray photoelectron spectroscopy to study the influence of the gas ratio in more detail. We achieved a surface roughness of Ra 0.6 nm on silicon wafers with a peak removal rate of approximately 32 $mm^{3}$/min.

Nonlinear dynamics analysis of multi-cutting wire electrode in WEDM-HS subjected to working fluid considering the effect of debris

Sheng-Yao Fan,Qiu-Ju Zhang,Hai-Wei Chen,Wen-xuan Zeng 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.12

A reasonable dielectric fluid velocity and better exclusion of debris are very important to obtain a stable machining performance in multi-cutting of WEDM-HS. We investigated the dynamic characteristics of multi-cutting wire electrode in WEDM-HS subjected to working fluid considering the effect of debris. First, a fluid-solid coupling nonlinear vibration model is derived by analyzing the forces acting on the multi-cutting wire which locate in the dielectric fluid. The additional axial force arising from the transverse vibration of the multi-cutting wire is considered as a nonlinear term in the model. Considering that the debris accumulation in discharge gap severely influences the stability of multi-cutting wire electrode, the relationship between the debris volume concentration and debris-working fluid two-phase flow drag coefficient is obtained using the Einstein two-phase flow viscosity theory. Finally, the influences of several parameters on the multi-cutting wire displacement are discussed in detail.

Icariside II Promotes the Differentiation of Adipose Tissue-Derived Stem Cells to Schwann Cells to Preserve Erectile Function after Cavernous Nerve Injury

Zheng, Tao,Zhang, Tian-biao,Wang, Chao-liang,Zhang, Wei-xing,Jia, Dong-hui,Yang, Fan,Sun, Yang-yang,Ding, Xiao-ju,Wang, Rui Korean Society for Molecular and Cellular Biology 2018 Molecules and cells Vol.41 No.6

Icariside II (ICA II) is used in erectile dysfunction treatment. Adipose tissue-derived stem cells (ADSCs) are efficient at improving erectile function. This study aimed to explore the action mechanism of ADSCs in improving erectile function. ADSCs were isolated from the adipose tissues of rats. Cell proliferation was determined using the Cell Counting Kit-8 (CCK-8) assay. The expressions of mRNA and protein were determined separately through qRT-PCR and western blot. The endogenous expressions of related genes were regulated using recombinant plasmids and cell transfection. A Dual-Luciferase Reporter Assay was performed to determine the interaction between miR-34a and STAT3. Rat models with bilateral cavernous nerve injuries (BCNIs) were used to assess erectile function through the detection of mean arterial pressure (MAP) and intracavernosal pressure (ICP). ICA II promoted ADSCs' proliferation and differentiation to Schwann cells (SCs) through the inhibition of miR-34a. Suppressed miR-34a promoted the differentiation of ADSCs to SCs by upregulating STAT3. ICA II promoted the differentiation of ADSCs to SCs through the miR-34a/STAT3 pathway. The combination of ICA II and ADSCs preserved the erectile function of the BCNI model rats. ADSCs treated with ICA II markedly preserved the erectile function of the BCNI model rats, which was reversed through miR-34a overexpression. ICA II promotes the differentiation of ADSCs to SCs through the miR34a/STAT3 pathway, contributing to erectile function preservation after the occurrence of a cavernous nerve injury.

Icariside II Promotes the Differentiation of Adipose Tissue-Derived Stem Cells to Schwann Cells to Preserve Erectile Function after Cavernous Nerve Injury

Tao Zheng,Tian-biao Zhang,Chao-liang Wang,Wei-xing Zhang,Dong-hui Jia,Fan Yang,Yang-yang Sun,Xiao-ju Ding,Rui Wang 한국분자세포생물학회 2018 Molecules and cells Vol.41 No.6

Icariside II (ICA II) is used in erectile dysfunction treatment. Adipose tissue-derived stem cells (ADSCs) are efficient at improving erectile function. This study aimed to explore the action mechanism of ADSCs in improving erectile function. ADSCs were isolated from the adipose tissues of rats. Cell proliferation was determined using the Cell Counting Kit-8 (CCK-8) assay. The expressions of mRNA and protein were determined separately through qRT-PCR and western blot. The endogenous expressions of related genes were regulated using recombinant plasmids and cell transfection. A Dual-Luciferase Reporter Assay was performed to determine the interaction between miR-34a and STAT3. Rat models with bilateral cavernous nerve injuries (BCNIs) were used to assess erectile function through the detection of mean arterial pressure (MAP) and intracavernosal pressure (ICP). ICA II promoted ADSCs’ proliferation and differentiation to Schwann cells (SCs) through the inhibition of miR-34a. Suppressed miR-34a promoted the differentiation of ADSCs to SCs by up-regulating STAT3. ICA II promoted the differentiation of ADSCs to SCs through the miR-34a/STAT3 pathway. The combination of ICA II and ADSCs preserved the erectile function of the BCNI model rats. ADSCs treated with ICA II markedly preserved the erectile function of the BCNI model rats, which was reversed through miR-34a overexpression. ICA II pro-motes the differentiation of ADSCs to SCs through the miR-34a/STAT3 pathway, contributing to erectile function preservation after the occurrence of a cavernous nerve injury.

Modeling and representation of a computer-aided conceptual design system

Bing Liang,Yuan Chen,Ju-Fan Zhang,Ying Hu 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.11

A novel hierarchical function action behavior mechanism (FABM) modeling framework is proposed to conduct intelligent mapping from the overall function to the principle solution, according to the requirements of customers. Based on the hierarchical modeling framework, an object-oriented representation method is developed to express the inheritance and the interconnecting characteristics between any two objects. In addition, the rules of expansion and modification in demand behavior are proposed to solve the combinational explosion problem, and the combinational rules in the mechanism behavior are developed to extend the innovation of the principle solution. A case study on the pan mechanism design for a cooking robot is presented to demonstrate the implementation of intelligent reasoning based on the FABM model.

Stiffness Modeling and Optimization of a 3-DOF Parallel Robot in a Serial-Parallel Polishing Machine

Peng Xu,Bing Li,Chi-Fai Cheung,Ju-Fan Zhang 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.4

Polishing is a kind of finishing process that can effectively reduce the surface defects and improve the form accuracy. This paper presents a novel hybrid machine with 6 degrees of freedom (DOF) serial-parallel topological structure used as an ultra-precision polishing equipment which is composed of a 3-DOF parallel robot, a 2-DOF serial robot and a turntable providing a redundant DOF. Due to the complexity of structure, stiffness performance evaluation of the parallel robot becomes a challenge. As a result, a theoretical model of the parallel robot based on the virtual work principle and the deformation superposition principle is formulated for analyzing the stiffness performance. With the developed model, a multi-objective dimensional optimization method is developed to maximize both the workspace volume and the global stiffness performance of the parallel robot. Artificial intelligence approach based on genetic algorithms is implemented to obtain an optimal combination of structural parameters. The effectiveness of this method is validated by simulation and the parallel robot with optimized structural parameters has a workspace with higher stiffness performance, hence justifies its suitability for high precision polishing.

method for vibration isolation of a vertical axis automatic washing machine with a hydraulic balancer

Hai-Wei Chen,Wei-Xi Ji,Qiu-Ju Zhang,Yi Cao,Sheng-Yao Fan 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.2

This paper discusses a method for vibration isolation of a vertical axis automatic washing machine with a hydraulic balancer. First, a way to isolate vibration through a small amplitude of the suspension rod’s axial force is proposed, and a base circle of a cone along which the lower joint of a suspension rod moves is discussed. Based on the circle, a geometric constraint involving the slant angle of the suspension rod, the deflection angle of the washing/spinning assembly, the suspension radius of the tub and the eccentricity of the system at the steady state is derived. Considering that the trace along which the suspension rod moves is also affected by the dynamics of the system, a governing equation satisfying the equilibrium conditions of the centrifugal forces and torques is obtained. Combing the geometric constraint and governing equation together achieves a general governing equation for vibration isolation of the system. Finally, the general governing equation is proven by simulations, and the relations between the optimal installing height and several parameters are discussed.

Investigation on crack propagation properties of flange-stiffened plate structure in a sleeve

Qinglin Lian,Huaji Wang,Xiaowei Ren,Xiaochen Fan,Dingshi Li,Jinbiao Zhao,Long Ju,Guodong Zhang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.11

A 3D FE model has been developed to investigate the crack propagation properties of flange-stiffened plate structure in a sleeve used for loading transition, according to practical observations of the crack morphology. The stress intensity factor (SIF) was applied to analyze the crack propagation properties along crack tip in different positions of the sleeve;simulation models including either one crack or multiple cracks were studied. Results showed that crack formation had insignificant influence on the structural effective stress and deformation variations. The faces of the crack formed at the bolt hole edge were opened, meanwhile the crack possessed the highest potential to grow, while cracks in the connecting fillet between flange and stiffened plate and the flange mounting interface were less likely to propagate. Compared with the one-crack model, when multiple cracks co-existed there were limited changes on the crack respective propagation properties.

YAP/TAZ-Mediated Upregulation of GAB2 Leads to Increased Sensitivity to Growth Factor–Induced Activation of the PI3K Pathway

Wang, Chao,Gu, Chao,Jeong, Kang Jin,Zhang, Dong,Guo, Wei,Lu, Yiling,Ju, Zhenlin,Panupinthu, Nattapon,Yang, Ji Yeon,Gagea, Mihai (Mike),Ng, Patrick Kwok Shing,Zhang, Fan,Mills, Gordon B. American Association for Cancer Research 2017 Cancer Research Vol.77 No.7

<P>Interactions between HIPPO, YAP/TAZ, and the PI3K/AKT pathway may be therapeutically targetable, providing new approaches to treating endometrial cancers and other cancers where the HIPPO pathway is a core oncogenic driver.</P><P>The transcription regulators YAP and TAZ function as effectors of the HIPPO signaling cascade, critical for organismal development, cell growth, and cellular reprogramming, and YAP/TAZ is commonly misregulated in human cancers. The precise mechanism by which aberrant YAP/TAZ promotes tumor growth remains unclear. The HIPPO tumor suppressor pathway phosphorylates YAP and TAZ, resulting in cytosolic sequestration with subsequent degradation. Here, we report that the PI3K/AKT pathway, which is critically involved in the pathophysiology of endometrial cancer, interacts with the HIPPO pathway at multiple levels. Strikingly, coordinate knockdown of YAP and TAZ, mimicking activation of the HIPPO pathway, markedly decreased both constitutive and growth factor–induced PI3K pathway activation by decreasing levels of the GAB2 linker molecule in endometrial cancer lines. Furthermore, targeting YAP/TAZ decreased endometrial cancer tumor growth <I>in vivo</I>. In addition, YAP and TAZ total and phosphoprotein levels correlated with clinical characteristics and outcomes in endometrial cancer. Thus, YAP and TAZ, which are inhibited by the HIPPO tumor suppressor pathway, modify PI3K/AKT pathway signaling in endometrial cancer. The cross-talk between these key pathways identifies potential new biomarkers and therapeutic targets in endometrial cancer. <I>Cancer Res; 77(7); 1637–48. ©2017 AACR</I>.</P>