The influence of mesh misalignment on the dynamic characteristics of helical gears including sliding friction

Hanjun Jiang,Yimin Shao,Chris K. Mechefske,Xiaohui Chen 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.11

Due to either elastic deformations or errors in the manufacturing or assembling of gears, shafts, bearings and their housings, it is an inevitableconsequence that mesh misalignment between teeth occurs. The change in length of the contact line or the change in load distributionalong the length of the contact line induced by mesh misalignment causes changes in the dynamic characteristics of helical gears. There is currently no satisfactory solution for the modeling and calculation of the internal excitation in helical gears with mesh misalignmentand sliding friction that would reveal the changes in the dynamic characteristics. In this study, an improved calculation method offriction excitation is proposed based on the time-varying length of the contact line and the time-varying friction coefficient model in helicalgears. By considering the change in the mesh position and the change in the length of the contact line or the change of the displacementerror along the contact line induced by mesh misalignment, the time-varying sliding friction force and the dynamic mesh force maybe obtained. An eight degree-of-freedom analytical helical gear pair model is developed by incorporating the time-varying sliding frictionforce and dynamic mesh force and considering the mesh misalignment. By assuming a constant mesh stiffness density along the contactline, the rules governing the variation of the dynamic response are obtained using simulations of helical gear pair examples with differentfriction coefficient models and mesh misalignment. The developed analytical model provides a new method for the study of excitationcharacteristics in helical gears with mesh misalignment.

Gene expression profile analysis indicate SEPALLATA3 and AGL15 potentially involved in arabidopsis silique dehiscence by regulating glycosyl hydrolase

Xingshan Jiang,Hanjun He,Ting Wang,Xiaojing Wang,Hong Wu 한국식물학회 2016 Journal of Plant Biology Vol.59 No.2

Fruit dehiscence is an essential developmental process for certain economic crops that dramatically impacts crop yields and involves the altered regulation of thousands of genes and corresponding biological processes. The regulation of fruit dehiscence is complex; although some regulatory genes have been characterized, the overall mechanism is still unknown. In this study, we used microarray analysis to screen the expression patterns of genes during three stages of Arabidopsis thaliana silique dehiscence (stages 11, 15, and 17). Differentially expressed genes (DEGs) were detected, and the combination of functional enrichment analysis with Short Time-series Expression Miner (STEM) clustering analysis was used to explore the overall gene expression changes and related functions during fruit dehiscence. A total of 9 specific gene expression clusters and corresponding functions were found. Moreover, transcription factor (TF) enrichment analysis for these gene clusters showed that two TFs (SEPALLATA3 and AGL15) maybe key regulatory factors for silique dehiscence because they target many glycosyl hydrolases in a certain cluster related to cell wall degradation. Taken together, our data enable connections to be drawn among specic biological functions, genes and TFs, which supports the development of network models to elucidate the process of silique dehiscence.

Dynamic behavior analysis of spur gears with constant & variable excitations considering sliding friction influence

Fuhao Liu,Hanjun Jiang,Shaona Liu,Xuehua Yu 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.12

A new analytical model of a spur gear system with sliding friction is presented. Unlike previous models, the excitation consists of two parts: the rotational driving speed of the pinion and the drag torque acting on the gear. The proposed model was validated with the finite element model. Using numerical method, the steady state resolutions was obtained to mainly demonstrate the nonlinear characteristics under both constant and variable excitations. The results obtained illustrate that sliding friction could introduce additional vibration. Moreover, the sliding friction even could decrease the dynamic transmission errors under proper operation condition. Further, the bifurcation diagram was plotted to show the influence of the rotational driving speed of the pinion on the dynamical characteristic of the gear system. Finally, the fluctuated excitation was used to exhibit their different effects on the gear system, which should form the basis of further analytical and experimental work in the gear dynamic area.

A Fully Integrated SoC for Smart Capsule Providing In-Body Continuous pH and Temperature Monitoring

Heng Liu,Hanjun Jiang,Jingpei Xia,Zhexiang Chi,Fule Li,Zhihua Wang 대한전자공학회 2016 Journal of semiconductor technology and science Vol.16 No.5

This paper presents a SoC (System-on-a-Chip) dedicated for a single-chip smart capsule which can be used to continuously monitor human alimentary canal pH and temperature values. The SoC is composed of the pH and temperature sensor interface circuit, a wireless transceiver, the power management circuit and the flow control logic. Fabricated in 0.18 μm standard CMOS technology, the SoC occupies a die area of ~9 mm². The SoC consumes 6.15 mW from a 3 V power supply, guaranteeing the smart capsule battery life is no less than 24 hours when using 50 mAh coin batteries. The experimental results show that measurement accuracy of the smart capsule is ±0.1 pH and ±0.2°C for pH and temperature sensing, respectively, which meets the requirement of in-body pH and temperature monitoring in clinical practice.

A Fully Integrated SoC for Smart Capsule Providing In-Body Continuous pH and Temperature Monitoring

Liu, Heng,Jiang, Hanjun,Xia, Jingpei,Chi, Zhexiang,Li, Fule,Wang, Zhihua The Institute of Electronics and Information Engin 2016 Journal of semiconductor technology and science Vol.16 No.5

This paper presents a SoC (System-on-a-Chip) dedicated for a single-chip smart capsule which can be used to continuously monitor human alimentary canal pH and temperature values. The SoC is composed of the pH and temperature sensor interface circuit, a wireless transceiver, the power management circuit and the flow control logic. Fabricated in $0.18{\mu}m$ standard CMOS technology, the SoC occupies a die area of ${\sim}9 mm^2$. The SoC consumes 6.15 mW from a 3 V power supply, guaranteeing the smart capsule battery life is no less than 24 hours when using 50 mAh coin batteries. The experimental results show that measurement accuracy of the smart capsule is ${\pm}0.1$ pH and ${\pm}0.2^{\circ}C$ for pH and temperature sensing, respectively, which meets the requirement of in-body pH and temperature monitoring in clinical practice.

Hippo signaling is intrinsically regulated during cell cycle progression by APC/C^Cdh1

Kim, Wantae,Cho, Yong Suk,Wang, Xiaohui,Park, Ogyi,Ma, Xueyan,Kim, Hanjun,Gan, Wenjian,Jho, Eek-hoon,Cha, Boksik,Jeung, Yun-ji,Zhang, Lei,Gao, Bin,Wei, Wenyi,Jiang, Jin,Chung, Kyung-Sook,Yang, Yingzi National Academy of Sciences 2019 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.116 No.19

<P><B>Significance</B></P><P>The Hippo signaling pathway is evolutionarily conserved in the animal kingdom and plays essential roles in regulating tissue growth during development and regeneration. We have identified APC/C<SUP>Cdh1</SUP>, a core component of cell cycle control machinery, as an evolutionarily conserved and previously unknown regulator of large tumor suppressor (LATS) kinases, which critically inhibit the YAP/TAZ transcription factors in transducing Hippo signaling. Our results suggest a model that APC/C<SUP>Cdh1</SUP> destabilizes LATS1/2 kinases in G1 phase of the cell cycle, leading to increased YAP/TAZ activities that promote G1/S transition by upregulating downstream gene expression, including <I>E2F1</I>. Our findings have important implications for a link between cell proliferation and LATS-regulated YAP/TAZ activities.</P><P>The Hippo-YAP/TAZ signaling pathway plays a pivotal role in growth control during development and regeneration and its dysregulation is widely implicated in various cancers. To further understand the cellular and molecular mechanisms underlying Hippo signaling regulation, we have found that activities of core Hippo signaling components, large tumor suppressor (LATS) kinases and YAP/TAZ transcription factors, oscillate during mitotic cell cycle. We further identified that the anaphase-promoting complex/cyclosome (APC/C)<SUP>Cdh1</SUP> E3 ubiquitin ligase complex, which plays a key role governing eukaryotic cell cycle progression, intrinsically regulates Hippo signaling activities. CDH1 recognizes LATS kinases to promote their degradation and, hence, YAP/TAZ regulation by LATS phosphorylation is under cell cycle control. As a result, YAP/TAZ activities peak in G1 phase. Furthermore, we show in <I>Drosophila</I> eye and wing development that Cdh1 is required in vivo to regulate the LATS homolog Warts with a conserved mechanism. Cdh1 reduction increased Warts levels, which resulted in reduction of the eye and wing sizes in a Yorkie dependent manner. Therefore, LATS degradation by APC/C<SUP>Cdh1</SUP> represents a previously unappreciated and evolutionarily conserved layer of Hippo signaling regulation.</P>