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Optimal simulation design for weight reduction of periodic titanium alloy space structures
Liang Xuan,Yanhe Zhang,Siyuan Peng,Yongkang Shen 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.2
This research investigates the spatial structure of periodic titanium alloys. The response surface optimization method is used to optimize the weight reduction structure of combined model parameters. Under the condition of unidirectional load, the stress and strain results of each model group of a 3D structure with weight reduction rates of 30 %, 50 %, and 70 % are obtained through simulation analysis. Furthermore, the characteristics of the selective laser melting (SLM) forming process are incorporated, and a comparative analysis of the maximum equivalent stress of each group of models under unidirectional load is performed. The optimal structural form and its parameters suitable for multi-directional loads are screened. By using SLM to form the optimal model and carry out a loading test, the ultimate load of the model under different weight reduction rates is obtained to provide a theoretical basis for the next step of 3D printing process research.
An Optical Zoom System Based on Tunable Lens with Polymer Membrane and Multilayered Structure
Dan Liang,Dong Tai Liang,Xuan Yin Wang 한국고분자학회 2018 폴리머 Vol.42 No.6
We have developed an optical zoom system based on tunable lens with polymer membrane and multilayered structure. The presented system employed two tunable lenses and two doublet lenses as the main refractive units. Each tunable lens had a delicately designed, solid-liquid mixed structure with multiple internal slim holes, which helped to improve the lens optical properties and stability against gravity. The optical structure and regulation principle of the zoom system is presented, as well as the detailed fabrication process of the tunable lens. Under different displacement loads, the lens deformation properties, and the adjustment ability and imaging characteristics of the zoom system were measured and analyzed. Besides, the spot diagram, field curvature and distortion of the system were simulated using the Zemax software. The magnification of the designed system could be regulated from 0.2X to 4.3X flexibly depending on the focal variation of each tunable lens.
Design and investigation of a cycloid helical gear drive
Xuan Li,Chaoyang Li,Bingkui Chen,Dong Liang 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.9
In this paper, an original analysis of the geometric design of a parallel-axis cycloid helical gear drive and an investigation on its basic meshing characteristics are presented. This type of gear drive consists of a pinion with one tooth and a cycloid-helix gear in continuous line contact along the whole length of the tooth. Firstly, mathematical formulations of their tooth surfaces are derived based on the envelope theory and homogeneous coordinate transformation. Secondly, the undercutting analysis is applied to determine the design constraint to avoid the undercutting on the cycloid-helix gear tooth surface. Then, the meshing characteristics including the contact lines, surface of action, induced normal curvature are analyzed. Numerical example is presented to demonstrate the influence of design parameters on the contact stress distribution. Finally, the loaded tooth contact analysis is performed to simulate the tooth contact condition and to validate the stress distribution by the finite element method.
Fabrication and Analyses of Bionic Polymer Lens System
Xuan Yin Wang,Dan Liang,Feng Tang,Jia Wei Du 한국고분자학회 2016 폴리머 Vol.40 No.2
In this paper, we design and fabricate a bionic solid tunable lens which is mainly made of polymer materials. The lens focal length can be changed flexibly by pressing the lens surface to alter the curvature radius. A detailed description of the lens structure, materials and fabrication process is presented. The lens mechanical properties and deformation process are simulated and analyzed using Ansys software. A precise experimental device based on a stepping motor is fabricated to measure and analyze the relationship between the displacement load and focal length. The lens focal length can be reversibly changed from 31.8 to 14.1 mm under 1 mm variation of displacement load. This paper offers a feasible way for the design, fabrication, and actuation of the solid tunable lens, which can be used in various machine vision apparatus.
Yingran Liang,Yuanyuan Zhang,Miaomiao Liu,Xue Han,Jianping Zhang,Xuan Zhang,Li Chu 대한약학회 2020 Archives of Pharmacal Research Vol.43 No.8
Many studies describe the stimulating eff ect ofquercetin on Ca 2+ channels and the treatment of cardiovasculardiseases such as myocardial ischemia and hypertension. However, these studies are scattered and contradictory. The aim of this study is to elucidate the protective eff ects ofquercetin against isoproterenol (ISO)-induced myocardialischemia and verify the cellular mechanisms based on theL-type Ca 2+ channel (LTCC), Ca 2+ transients, and myocardialcontractility. An animal model of myocardial ischemiawas established by subcutaneous injection of ISO for 2 days. Quercetin significantly reduced J-point elevation, heartrate, reactive oxygen species, serum levels of myocardialenzymes, superoxide dismutase, catalase, glutathione, glutathioneperoxidase, glutathione S-transferase and improvedheart pathologic morphology. L-type Ca 2+ current (I Ca-L )was tested in an experiment with isolated rat myocardialcells by using the whole-cell patch-clamp recording techniqueand IonOptix Myocam detection system. Quercetin reduced I Ca-L in a concentration-dependent fashion with ahalf-maximal inhibitory concentration of 4.67 × 10 –4 M. Quercetin also shifted the current–voltage curve upwards,moved the activation and inactivation curves to the left andinhibited the amplitude of the cell shortening and Ca 2+ transients. The results showed that quercetin acts as a LTCCinhibitor and exerts a cardioprotective eff ect by inhibitingCa 2+ infl ux and contractility in rats.
Facial Feature Extraction Based on Weighted ALW and Pulse-Coupled Neural Network
Junhua Liang,Zhisheng Zhao,Xiao Zhang,Xuan Wang,Yang Liu 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.8
In order to improve the robustness of face identification with the changes of illumina-tion, expression and facial alteration, a new facial feature extraction algorithm based on weighted adaptive lifting wavelet(ALW) scheme and pulse-coupled neural network (PCNN) is involved in this paper. The face images are decomposed into several subbands by weighted adaptive lifting scheme. Then the PCNN is utilized to decompose each weighted subbands into a series of binary images, the entropies of which are calculated and regarded as facial features. Experimental results show that the method yields a good robustness against the illumination, expression and facial variability and reduces the computer burden.
Preparation of Thermosensitive Hydrogels by means of Tandem Physical and Chemical Crosslinking
Hong-Liang Wei,Kai Yao,Zhe Yang,Hui-Juan Chu,Jing Zhu,Cun-Cai Ma,Zi-Xuan Zhao 한국고분자학회 2011 Macromolecular Research Vol.19 No.3
The tandem physical and chemical crosslinking was used to prepare injectable hydrogels. First, the terpolymers with diene groups were synthesized by the free radical copolymerization of N-isopropylacrylamide (NIPA), N,N-dimethylacrylamide (DMA) and furfuryl methacrylate (FM). Second, dienophile-functionalized terpolymers were obtained from the terpolymers of NIPA, DMA, and 2-hydroxyethyl methacrylate (HEMA) and Nmaleoyl alanine (AMI) by a coupling reaction under N,N'-dicyclohexylcarbodiimide (DCC). When the screened diene-functionalized terpolymer and dienophile-functionalized terpolymer were dissolved separately in water and mixed, physically cross-linked hydrogels formed rapidly within 10 s at 37 ℃. Subsequently, the physically crosslinked hydrogels could change gradually into chemically cross-linked hydrogels by a Diels-Alder reaction and the mechanical strength of the hydrogels could be improved. The swelling behavior study suggests that the hydrogels possess thermosensitivity and good reproducibility at different temperatures. The strategy described, i.e. incorporating the advantages of physically crosslinked hydrogels and chemically crosslinked hydrogels, has potential applications in the preparation of injectable hydrogels.
Mechanical evaluation of polymer microneedles for transdermal drug delivery: In vitro and in vivo
Rui Xuan Liu,Yu Ting He,Ling Liang,Liu Fu Hu,Yue Liu,Rui-xing Yu,Bo Zhi Chen,Yong Cui,Xin Dong Guo 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.114 No.-
In this study, we reported two types of PMNs based on polylactic acid (PLA) and polyvinyl alcohol (PVA),respectively. Parafilm M film, porcine skin, and rats’ models were operated to evaluate the mechanicalproperties in vitro and in vivo to find optimal parameters for efficient insertion. Insertion depth was measuredusing Digital Force Gauge by changing insertion force and speed, respectively. Results showed thatincreasing the insertion force and speed used for PMNs application led to a significant increase in thedepth of insertion. A force of 18 N under a speed of 330 mm/min was the optimal condition for insertingPMNs array into ParafilmM film and porcine skin. In addition, PLA-MNs exhibited higher robustness andenhanced homogeneity in insertion depth compared with PVA-MNs, but PVA-MNs were able to reachmuch deeper insertion depth. Moreover, Sprague Dawley (SD) rat experiments confirmed the effectivenessof optimal insertion parameters for transdermal drug delivery. This study illustrated not only thedevelopment of novel PMNs but also the mechanical evaluation for the design of PMNs.