VALVE MOTION CHARACTERISTICS AND APPLICATION ON ENGINE BASED ON A NEW VARIABLE VALVE ACTUATION SYSTEM

You Zhou,Weihong Zhou,Fangxi Xie,Yu Liu,Xiaoping Li,Xun Gong 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.1

A new mechanical-hydraulic variable valve actuation (VVA) system was developed and a thin-wall orifice velocity control system were analyzed. Meanwhile, influence of speed, needle valve overflow area, oil temperature and oil supply pressure on valve motion characteristics were explored, as well as the VVA system have been applied on a single-cylinder engine preliminary. By the VVA system, valve lifts can be adjusted from maximum of 8.7 mm to fully closing. Valve seating velocity decreased with orifice diameter reducing. Seating velocity can be maintained below 0.5 m/s with 0.8 mm diameter of thin-wall orifice and 3 mm check valve moving distance. Besides that, velocity control system also can help improve the coefficient of cyclic variation of maximum valve lift. Except for the needle valve closing state, valve lift decreased with oil temperature increasing and operating speed reducing under the same needle valve state. Oil supply pressure hardly had no influence on valve lifts, but delayed valve opening timing with pressure decreasing. Thin-wall orifice seating velocity control system was not sensitive to variable oil temperature and supply pressure. Compared with conventional engine, adjusting intake valve by VVA system under un-throttle internal EGR strategy, can improve BSFC and NOX emissions significantly about 13.8 % and 19.8 % on 6 bar IMEP.

A New Model and Equation Derived From Surface Tension and Cohesive Energy Density of Coagulation Bath Solvents for Effective Precipitation Polymerization of Acrylonitrile

You Zhou,Liwei Xue,Kai Yi,Li Zhang,Seung Kon Ryu,Ri Guang Jin 한국탄소학회 2012 Carbon Letters Vol.13 No.3

A new model and resultant equation for the coagulation of acrylonitrile monomers in precipitation polymerization are suggested in consideration of the surface tension (γ) and cohesive energy density (ECED). The equation was proven to be quite favorable by considering figure fittings from known surface tensions and cohesive energy densities of certain organic solvents. The relationship between scale value of surface tension (γ/M) and cohesive energy density of monomers can be obtained by changing the coagulation bath component for effective precipitation polymerization of acrylonitrile in wet spinning.

SLQE : An Improved Link Quality Estimation based on Four-bit LQE

An Zhou,Baowei Wang,Xingming Sun,Xingang You,Huiyu Sun,Tao Li 보안공학연구지원센터 2015 International Journal of Future Generation Communi Vol.8 No.1

Link quality estimation (LQE) is an effective basic building block in wireless sensor networks (WSNs) and higher cross layer design of network protocol. Some researchers have investigated the statistical properties of the link quality estimators independently from higher-layer protocols, and their impact on the Collection Tree Routing Protocol (CTP). Then they set up a dedicated LQE, independent of the protocol interface, which has in total of four bits information: one from the physical layer, one from the link layer, and two from the network layer. Four-bit has been found to be a good estimator; however its performance heavily depends on the tuning of its parameters. But we found that Four-bit couldn’t be working effectively in responding to the burst situation after repeated experiments. So we redesigned the link estimation method, called Stable Link Quality Estimation (SLQE), which combines active probing with passive snooping to make estimation more stable. We have found that the new design can cope with the emergency. Moreover it also enhances the robustness of the network, and saves the overall energy consumption of the network.

Bio-inspired leaf stent for direct treatment of cerebral aneurysms: design and finite element analysis

Zhou, Xiang,You, Zhong,Byrne, James M.D. Techno-Press 2011 Smart Structures and Systems, An International Jou Vol.8 No.1

Cerebral aneurysm is common lesion among adult population. Current methods for treating the disease have several limitations. Inspired by fern leaves, we have developed a new stent, called leaf stent, which can provide a tailored coverage at the neck of an aneurysm and thus prevent the blood from entering the aneurysm. It alone can be used to treat the cerebral aneurysm and therefore overcomes problems existing in current treating methods. The paper focuses on the numerical simulation of the leaf stents. The mechanical behaviour of the stent in various designs has been investigated using the finite element method. It has been found that certain designs provide adequate radial force and have excellent longitudinal flexibility. The performance of certain leaf stents is comparable and even superior to those of the commercially available cerebral stents such as the Neuroform stent and the Enterprise stent, commonly used for stent assisted coiling, while at the same time, providing sufficient coverage to isolate the aneurysm without using coils.

IL-12-STAT4-IFN-γ axis is a key downstream pathway in the development of IL-13-mediated asthma phenotypes in a Th2 type asthma model

You-Sun Kim,Seng-Jin Choi,Jun-Pyo Choi,전성규,이병재,고용송,이춘근,Jack A. Elias,Yoon-Keun Kim,Sun-Young Oh,Zhou Zhu 생화학분자생물학회 2010 Experimental and molecular medicine Vol.42 No.8

IL-4 and IL-13 are closely related cytokines that are produced by Th2 cells. However, IL-4 and IL-13 have different effects on the development of asthma phenotypes. Here, we evaluated downstream molecular mechanisms involved in the development of Th2 type asthma phenotypes. A murine model of Th2 asthma was used that involved intraperitoneal sensitization with an allergen (ovalbumin) plus alum and then challenge with ovalbumin alone. Asthma phenotypes, including airway-hyperresponsiveness (AHR), lung inflammation,and immunologic parameters were evaluated after allergen challenge in mice deficient in candidate genes. The present study showed that methacholine AHR and lung inflammation developed in allergen-challenged IL-4-deficient mice but not in allergen-challenged IL-13-deficient mice. In addition, the production of OVA-specific IgG2a and IFN-γ-inducible protein (IP)-10was also impaired in the absence of IL-13, but not of IL-4. Lung-targeted IFN-γ over-expression in the airways enhanced methacholine AHR and non-eosinophilic inflammation; in addition, these asthma phenotypes were impaired in allergen-challenged IFN-γ-deficient mice. Moreover, AHR, non-eosinophilic inflammation,and IFN-γ expression were impaired in allergen-challenged IL-12Rβ2- and STAT4-deficient mice; however, AHR and non-eosinophilic inflammation were not impaired in allergen-challenged IL-4Rα-deficient mice, and these phenomena were accompanied by the enhanced expression of IL-12 and IFN-γ. The present data suggest that IL-13-mediated asthma phenotypes, such as AHR and non-eosinophilic inflammation, in the Th2 type asthma are dependent on the IL-12-STAT4-IFN-γ axis, and that these asthma phenotypes are independent of IL-4Ralpha-mediated signaling.

A new phenylethanoid glycoside with antioxidant and anti-HBV activity from Tarphochlamys affinis

Zhou, Xian-Li,Wen, Qing-Wei,Lin, Xing,Zhang, Shi-Jun,Li, Ying-Xin,Guo, You-Jia,Huang, Ren-Bin 대한약학회 2014 Archives of Pharmacal Research Vol.37 No.5

A new phenylethanoid glycoside, named taraffinisoside A (1), together with five known glycosides were isolated from the stems and leaves of Tarphochlamys affinis. The structure of taraffinisoside A was identified on the basis of detailed spectral analysis. Compounds 1-4 and 6 showed potent antioxidant activities with $IC_{50}$ values of 10.36, 19.73, 43.95, 15.30 and $46.04{\mu}M$ by 1,1-diphenyl-2-picryhydrazyl radical-scavenging assay. Compounds 1, 2 and 4 showed anti-HBV activities, with $IC_{50}$ values of 0.50, 0.72 and 0.26 mM for HBsAg and 0.93, 0.42 and 0.07 mM for HBeAg, respectively.

MicroRNA-766-3p Inhibits Tumour Progression by Targeting Wnt3a in Hepatocellular Carcinoma

You, Yu,Que, Keting,Zhou, Yun,Zhang, Zhen,Zhao, Xiaoping,Gong, Jianpin,Liu, Zuojin Korean Society for Molecular and Cellular Biology 2018 Molecules and cells Vol.41 No.9

Recent studies have indicated that microRNAs (miRNAs) play an important role in hepatocellular carcinoma (HCC) progression. In this study, we showed that miR-766-3p was decreased in approximately 72% of HCC tissues and cell lines, and its low expression level was significantly correlated with tumour size, TNM stage, metastasis, and poor prognosis in HCC. Ectopic miR-766-3p expression inhibited HCC cell proliferation, colony formation, migration and invasion. In addition, we showed that miR-766-3p repressed Wnt3a expression. A luciferase reporter assay revealed that Wnt3a was a direct target of miR-766-3p, and an inverse correlation between miR-766-3p and Wnt3a expression was observed. Moreover, Wnt3a up-regulation reversed the effects of miR766-3p on HCC progression. In addition, our study showed that miR-766-3p up-regulation decreased the nuclear ${\beta}-catenin$ level and expression of Wnt targets (TCF1 and Survivin) and reduced the level of MAP protein regulator of cytokinesis 1 (PRC1). However, these effects of miR-766-3p were reversed by Wnt3a up-regulation. In addition, PRC1 upregulation increased the nuclear ${\beta}-catenin$ level and protein expression of TCF1 and Survivin. iCRT3, which disrupts the ${\beta}-catenin-TCF4$ interaction, repressed the TCF1, Survivin and PRC1 protein levels. Taken together, our results suggest that miR-766-3p down-regulation promotes HCC cell progression, probably by targeting the Wnt3a/PRC1 pathway, and miR-766-3p may serve as a potential therapeutic target in HCC.

NEDD4 Regulated Pyroptosis Occurred from Co-infection between Influenza A Virus and Streptococcus pneumoniae

You Jiangzhou,Zhou Linlin,San Xudong,Li Hailing,Li Mingyuan,Wang Baoning 한국미생물학회 2023 The journal of microbiology Vol.61 No.8

Co-infection of respiratory tract viruses and bacteria often result in excess mortality, especially pneumonia caused by influenza viruses and Streptococcus pneumoniae. However, the synergistic mechanisms remain poorly understood. Therefore, it is necessary to develop a clearer understanding of the molecular basis of the interaction between influenza virus and Streptococcus pneumonia. Here, we developed the BALB/c mouse model and the A549 cell model to investigate inflammation and pyroptotic cell death during co-infection. Co-infection significantly activated the NLRP3 inflammasome and induced pyroptotic cell death, correlated with excess mortality. The E3 ubiquitin ligase NEDD4 interacted with both NLRP3 and GSDMD, the executor of pyroptosis. NEDD4 negatively regulated NLRP3 while positively regulating GSDMD, thereby modulating inflammation and pyroptotic cell death. Our findings suggest that NEDD4 may play a crucial role in regulating the GSDMD-mediated pyroptosis signaling pathway. Targeting NEDD4 represents a promising approach to mitigate excess mortality during influenza pandemics by suppressing synergistic inflammation during co-infection of influenza A virus and Streptococcus pneumoniae.

Changes in element accumulation, phenolic metabolism, and antioxidative enzyme activities in the red-skin roots of Panax ginseng

Zhou, Ying,Yang, Zhenming,Gao, Lingling,Liu, Wen,Liu, Rongkun,Zhao, Junting,You, Jiangfeng The Korean Society of Ginseng 2017 Journal of Ginseng Research Vol.41 No.3

Background: Red-skin root disease has seriously decreased the quality and production of Panax ginseng (ginseng). Methods: To explore the disease's origin, comparative analysis was performed in different parts of the plant, particularly the epidermis, cortex, and/or fibrous roots of 5-yr-old healthy and diseased red-skin ginseng. The inorganic element composition, phenolic compound concentration, reactive oxidation system, antioxidant concentrations such as ascorbate and glutathione, activities of enzymes related to phenolic metabolism and oxidation, and antioxidative system particularly the ascorbate-glutathione cycle were examined using conventional methods. Results: Aluminum (Al), iron (Fe), magnesium, and phosphorus were increased, whereas manganese was unchanged and calcium was decreased in the epidermis and fibrous root of red-skin ginseng, which also contained higher levels of phenolic compounds, higher activities of the phenolic compound-synthesizing enzyme phenylalanine ammonia-lyase and the phenolic compound oxidation-related enzymes guaiacol peroxidase and polyphenoloxidase. As the substrate of guaiacol peroxidase, higher levels of $H_2O_2$ and correspondingly higher activities of superoxide dismutase and catalase were found in red-skin ginseng. Increased levels of ascorbate and glutathione; increased activities of $\text\tiny L$-galactose 1-dehydrogenase, ascorbate peroxidase, ascorbic acid oxidase, and glutathione reductase; and lower activities of dehydroascorbate reductase, monodehydroascorbate reductase, and glutathione peroxidase were found in red-skin ginseng. Glutathione-S-transferase activity remained constant. Conclusion: Hence, higher element accumulation, particularly Al and Fe, activated multiple enzymes related to accumulation of phenolic compounds and their oxidation. This might contribute to red-skin symptoms in ginseng. It is proposed that antioxidant and antioxidative enzymes, especially those involved in ascorbate-glutathione cycles, are activated to protect against phenolic compound oxidation.

Online damage detection using pair cointegration method of time-varying displacement

Zhou, Cui,Li, Hong-Nan,Li, Dong-Sheng,Lin, You-Xin,Yi, Ting-Hua Techno-Press 2013 Smart Structures and Systems, An International Jou Vol.12 No.3

Environmental and operational variables are inevitable concerns by researchers and engineers when implementing the damage detection algorithm in practical projects, because the change of structural behavior could be masked by the conditions in a large extent. Thus, reliable damage detection methods should have a virtue of immunity from environmental and operational variables. In this paper, the pair cointegration method was presented as a novel way to remove the effect of environmental variables. At the beginning, the concept and procedure of this approach were introduced, and then the theoretical formulation and numerical simulations were put forward to illustrate the feasibility. The jump exceeding the control limit in the residual indicates the occurrence of damage, while the direction and magnitude imply the most potential damage location. In addition, the simulation results show that the proposed method has strong ability to resist the noise.