Friction Experiment of Linear Motion Roller Guide THK SRG25

Cheng, De-Jun,Yang, Wan-Suk,Park, Je-Hong,Park, Tae-Jo,Kim, Su-Jin,Kim, Gyung-Ho,Park, Chun-Hong 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.15 No.3

Friction is a characteristic that can be found in machine elements in common engineering use, and it has great effect on the machining performance of a machine tool. Linear motion (LM) guides supported by rolling elements are used for accurate positioning of precision machine. For accurate positioning, the frictional behavior of the LM guide must be understood. In this investigation, a new experiment is conducted to measure friction, and the behavior of LM roller guide friction is measured under various external loads, preloads, velocities, and lubricants. The results obtained from experiment are compared with reference data, and the experimental friction equation of LM roller guide THK SRG25 is achieved from experiment, which can be used to calculate LM roller guide friction and control positioning accuracy.

Performance evaluation of soil-embedded plastic optical fiber sensors for geotechnical monitoring

Cheng-Cheng Zhang,Hong-Hu Zhu,Bin Shi,Jun-Kuan She,Dan Zhang 국제구조공학회 2016 Smart Structures and Systems, An International Jou Vol.17 No.2

Based on the distributed fiber optic sensing (DFOS) technique, plastic optical fibers (POFs) are attractive candidates to measure deformations of geotechnical structures because they can withstand large strains before rupture. Understanding the mechanical interaction between an embedded POF and the surrounding soil or rock is a necessary step towards establishing an effective POF-based sensing system for geotechnical monitoring. This paper describes a first attempt to evaluate the feasibility of POF-based soil deformation monitoring considering the POF–soil interfacial properties. A series of pullout tests were performed under various confining pressures (CPs) on a jacketed polymethyl methacrylate (PMMA) POF embedded in soil specimens. The test results were interpreted using a fiber–soil interaction model, and were compared with previous test data of silica optical fibers (SOFs). The results showed that the range of CP in this study did not induce plastic deformation of the POF; therefore, the POF–soil and the SOF–soil interfaces had similar behavior. CP was found to play an important role in controlling the fiber–soil interfacial bond and the fiber measurement range. Moreover, an expression was formulated to determine whether a POF would undergo plastic deformation when measuring soil deformation. The plasticity of POF may influence the reliability of measurements, especially for monitored geo-structures whose deformation would alternately increase and decrease. Taken together, these results indicate that in terms of the interfacial parameters studied here the POF is feasible for monitoring soil deformation as long as the plastic deformation issue is carefully addressed.

Radiological gastrostomy: A comparative analysis of different image-guided methods

Hong-Tao Hu,Hang Yuan,Chen-Yang Guo,Quan-Jun Yao,Xiang Geng,Hong-Tao Cheng,Jun-Li Ma,Yan Zhao,Li Jiang,Yu-Qing Zhao,Hai-Liang Li 소화기인터벤션의학회 2021 International journal of gastrointestinal interven Vol.10 No.2

Background: Radiographic guided percutaneous gastrostomy has become a safe and effective enteral nutrition method for patients who can not eat by mouth. Fluoroscopy, computed tomography (CT) and cone-beam CT have been routinely used clinically. The aim of this study was to compare the advantages and disadvantages of percutaneous gastrostomy using different radiographic guided methods. Methods: We retrospectively analyzed the clinical data of 538 patients undergoing percutaneous gastrostomy in our department. According to the image guidance method used in gastrostomy, the patients were divided into groups A by fluoroscopy guidance, group B by fluoroscopy combined with C-arm CT guidance, and group C with the whole process CT guidance. The gastrostomy success rate, complication rate, procedure time, and patient radiation dose were analyzed in the three groups. Results: Among 538 patients, 534 were successful and the success rates are 94.3%, 99.3%, and 100% in group A, B, and C, respectively (P > 0.05). There were 3 cases occurred postoperative bleeding as serious adverse events and transferred to surgical gastrostomy. The minor complications include local infection, hyperplasia of granulation tissue, tube obstruction or prolapse, and local pain of the ostomy. The minor complication rates were 10.5%, 10.4%, and 7.7% in group A, B, and C, respectively (P > 0.05). The average procedure time was 25.57 ± 5.99 minutes, 29.01 ± 6.63 minutes, and 45.47 ± 8.98 minutes, respectively (χ2 = 87.98, P < 0.001). The average radiation dosage was 27.30 ± 19.27 mGy, 145.07 ± 106.08 mGy, and 2,590.26 ± 1,088.22 mGy, respectively (χ2 = 204.44, P < 0.001). Conclusion: There were no significant differences in the success rates and complication rates of gastrostomy under the three guiding methods. For difficult cases, CT-guided gastrostomy may be a very useful supplemental method.

Radiological gastrostomy: A comparative analysis of different image-guided methods

Hong-Tao Hu,Hang Yuan,Chen-Yang Guo,Quan-Jun Yao,Xiang Geng,Hong-Tao Cheng,Jun-Li Ma,Yan Zhao,Li Jiang,Yu-Qing Zhao,Hai-Liang Li 소화기인터벤션의학회 2021 Gastrointestinal Intervention Vol.10 No.2

Background: Radiographic guided percutaneous gastrostomy has become a safe and effective enteral nutrition method for patients who can not eat by mouth. Fluoroscopy, computed tomography (CT) and cone-beam CT have been routinely used clinically. The aim of this study was to compare the advantages and disadvantages of percutaneous gastrostomy using different radiographic guided methods. Methods: We retrospectively analyzed the clinical data of 538 patients undergoing percutaneous gastrostomy in our department. According to the image guidance method used in gastrostomy, the patients were divided into groups A by fluoroscopy guidance, group B by fluoroscopy combined with C-arm CT guidance, and group C with the whole process CT guidance. The gastrostomy success rate, complication rate, procedure time, and patient radiation dose were analyzed in the three groups. Results: Among 538 patients, 534 were successful and the success rates are 94.3%, 99.3%, and 100% in group A, B, and C, respectively (P > 0.05). There were 3 cases occurred postoperative bleeding as serious adverse events and transferred to surgical gastrostomy. The minor complications include local infection, hyperplasia of granulation tissue, tube obstruction or prolapse, and local pain of the ostomy. The minor complication rates were 10.5%, 10.4%, and 7.7% in group A, B, and C, respectively (P > 0.05). The average procedure time was 25.57 ± 5.99 minutes, 29.01 ± 6.63 minutes, and 45.47 ± 8.98 minutes, respectively (χ2 = 87.98, P < 0.001). The average radiation dosage was 27.30 ± 19.27 mGy, 145.07 ± 106.08 mGy, and 2,590.26 ± 1,088.22 mGy, respectively (χ2 = 204.44, P < 0.001). Conclusion: There were no significant differences in the success rates and complication rates of gastrostomy under the three guiding methods. For difficult cases, CT-guided gastrostomy may be a very useful supplemental method.

Experimental Investigations of LM Roller Bearing Deformation

De-Jun Cheng,Wan-Seok Yang,Jae-Hong Park,Sun-Jin Kim,Gyung-Ho Kim,Chun-Hong Park 한국생산제조학회 2012 한국생산제조시스템학회 학술발표대회 논문집 Vol.2012 No.10

The effect of coffee capsule packing color on customers’ perceived coffee flavor

Jun Jie Deng(등준걸),Hong-In Cheng(정홍인) 대한인간공학회 2021 대한인간공학회 학술대회논문집 Vol.2021 No.6

UPPER BODY WORKLOAD ANALYSIS DUE TO THE DELIVERY CART TYPES

HONG-IN CHENG(정홍인),JUN JIE DENG(등준걸),CHAN WOO BYEON(변찬우) 대한산업공학회 2022 대한산업공학회 추계학술대회논문집 Vol.2022 No.11

Finite-time Boundness of H∞ Filtering for Switching Discrete-Time Systems

Jun Cheng,Hong Zhu,Shouming Zhong,Yu-Ping Zhang 제어·로봇·시스템학회 2012 International Journal of Control, Automation, and Vol.10 No.6

For switched discrete-time systems, switching behavior always affect the finite-time stability property, which was neglected by most previous research. This paper investigated the problem of finite-time boundness of H∞ filtering for switched discrete-time systems. Sufficient conditions which can ensure finite-time bounded and H∞ filtering finite-time boundness under arbitrary switching are derived. Based on the results of finite-time boundness and stochastic character, the closed-loop system trajectory stays within a prescribed bound. An example is given to illustrate the efficiency of the proposed method.

Generation of Selenoprotein with Glutathione Peroxidase Activity by Chemical Modification of the Single-chain Variable Fragment Expressed in a Single-protein Production System and Its Antioxidant Ability

Cheng Wang,Gang-Lin Yan,Shao-Wu Lü,Chun-Hong Sui,Yang Zhao,Ya-Wei Xu,Gang Zhao,Jun-jie Xu,Ping-Sheng Gong,Gui-Min Luo,Ying Mu 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.1

Glutathione peroxidase (GPX) is one of the important members of the antioxidant enzyme family. It can catalyze the reduction of hydroperoxides with glutathione to protect cells against oxidative damage. Single-chain variable fragment (scFv) can be converted into seleniumcontaining single-chain variable fragment (Se-scFv) by chemical modification of the hydroxyl groups in scFv, thus Se-scFv possesses GPX activity and becomes a prodrug. To improve the expression of scFv and simplify its purification steps, Single-protein production (SPP) system was used to express scFv and chemical modification was used to synthesize Se-scFv. Therefore, we must construct a new scFv-WCD1-lessACA gene, which can express its mRNA not containing any ACA sequences and express its amino acid sequence of target protein (scFv) being same to scFv-WCD1. In this way, the scFv-WCD1-lessACA can be only expressed in SPP system and no other background proteins in the cells could be expressed. The expression results showed that high level of scFv-WCD1-lessACA synthesis was at least sustained for 96 h in the virtual absence of background protein synthesis. Then, selenocysteine (Sec) was incorporated into the scFv-WCD1-lessACA by chemical modification and resulted in Se-scFv-WCD1-lessACA. The enzymatic characteristics of Se-scFv-WCD1-lessACA were determined. GPX activity was 2,563 U/μmol,its binding constant for GSH was 0.687 ×105/mol. Moreover,Se-scFv-WCD1-lessACA was confirmed to have a strong antioxidant ability to protect mitochondria against oxidative damage induced by Vc/Fe2+ (mitochondrial damage model),suggesting that Se-scFv-WCD1-lessACA has potential application for protection of mitochondrial damage induced by reactive oxygen species (ROS).

Enhanced CO methanation over Ni-based catalyst using a support with 3D-mesopores

Hong-Xia Cao,Jun Zhang,Xiang-Kun Ren,Cheng-Long Guo 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.9

Ni-based catalysts supported on a support with 3D-mesopores, including Ni/KIT-6(EG), Ni/KIT-6(PS) and Ni/KIT-6(DS), were prepared by adding ethylene glycol, direct synthesis and post synthesis methods, respectively, and their catalytic properties were investigated for CO methanation as one of the core technologies of synthetic natural gas production in a continuous flow fixed-bed reactor. The catalysts were characterized by N2 adsorption-desorption, X-ray diffraction (XRD), transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDS), hydrogen temperature-programmed reduction (H2-TPR), hydrogen temperature-programmed desorption (H2-TPD) and thermal gravimetric analysis (TGA), respectively. The results showed that Ni/KIT-6(EG) exhibited the best catalytic performance with CO conversion of almost 100% and CH4 yield of 75% at 450 oC, atmospheric pressure and 60,000 mL/g/h due to the higher dispersion of Ni species, stronger reducibility of NiO and formation of smaller Ni nanoparticles fixed into 3D-mesopores, indicating that adding ethylene glycol was effective to improve catalytic performance of Ni-based catalyst for CO methanation. Moreover, compared with Ni/Al2O3(EG) prepared using Al2O3 as a support, Ni/KIT- 6(EG) showed better catalytic performance owing to the higher specific surface area, stronger reducibility of NiO and confinement effect of 3D-mesopores promoting to produce more active sites. After 60h lifetime test of Ni/KIT-6(EG) at 500 oC, atmospheric pressure and 60,000mL/g/h, 3D-mesopores were still maintained and no obvious agglomeration of Ni nanoparticles was observed, meaning that Ni species were still well dispersed into 3D-mesopores. As a consequence, Ni/KIT-6(EG) exhibited superior catalytic performance and stability, which makes it a promising candidate for CO methanation.