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A Study on Cutting and Tribology Performances of TiN and TiAlN Coated Tools
Hua-Ying Li,Hui-Bo He,Wen-Qiang Han,Jun Yang,Tao Gu,Yuan-ming Li,류성기 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.
TiN and TiAlN coatings were deposited on the surface of AISI 5140 steel and cemented carbide YT15 by magnetron sputteringtechnique (MSP). The reciprocating sliding tests of TiN and TiAIN coatings on the surface of AISI 5140 steel were performed toinvestigate the friction coefficients of coatings affected by various normal loads with friction pair of 304 stainless steel balls. Drymachining tests on AISI 5140 hardened steel were carried out with the TiN and TiAlN coated tools on a CA6140A lathe. The effectsof cutting speed on cutting forces and surface roughness of TiN and TiAlN coated tools were obtained and analyzed to assess thecutting performance of coated tools. The microcosmic micrographs of wear areas of coated tools were observed and investigated byscanning electron microscope and energy dispersive spectrum. The results show that the friction coefficients of TiN coatings are lowerthan that of TiAlN coatings. The cutting force of TiAlN coated tool decreases and flank wear resistance enhances in comparison withTiN coated tool. The wear form and mechanisms of TiN coated tool are mainly crater wear on the rake face and adhesive wear andabrasive wear on the flank face. The wear form and mechanisms of TiAlN coated tool are mainly adhesive wear, the breakage ofcutting edge and the damage of tip, accompanied with diffusion and oxidation wear.
A Study on Cutting and Tribology Performances of TiN and TiAlN Coated Tools
Li, Hua-Ying,He, Hui-Bo,Han, Wen-Qiang,Yang, Jun,Gu, Tao,Li, Yuan-ming,Lyu, Sung-Ki Korean Society for Precision Engineering 2015 International Journal of Precision Engineering and Vol.16 No.4
TiN and TiAlN coatings were deposited on the surface of AISI 5140 steel and cemented carbide YT15 by magnetron sputtering technique (MSP). The reciprocating sliding tests of TiN and TiAIN coatings on the surface of AISI 5140 steel were performed to investigate the friction coefficients of coatings affected by various normal loads with friction pair of 304 stainless steel balls. Dry machining tests on AISI 5140 hardened steel were carried out with the TiN and TiAlN coated tools on a CA6140A lathe. The effects of cutting speed on cutting forces and surface roughness of TiN and TiAlN coated tools were obtained and analyzed to assess the cutting performance of coated tools. The microcosmic micrographs of wear areas of coated tools were observed and investigated by scanning electron microscope and energy dispersive spectrum. The results show that the friction coefficients of TiN coatings are lower than that of TiAlN coatings. The cutting force of TiAlN coated tool decreases and flank wear resistance enhances in comparison with TiN coated tool. The wear form and mechanisms of TiN coated tool are mainly crater wear on the rake face and adhesive wear and abrasive wear on the flank face. The wear form and mechanisms of TiAlN coated tool are mainly adhesive wear, the breakage of cutting edge and the damage of tip, accompanied with diffusion and oxidation wear.
An Effective Pre - refresh Mechanism for Mobile Handheld Device's Embedded Web Browser
Hua Qiang Li,Young Hak Kim 한국정보과학회 2002 한국정보과학회 학술발표논문집 Vol.29 No.2Ⅲ
Mobile handheld devices such as PDA(Personal Digital Assistant) and Cellular Phone are more and more popular for personal web surfing. But today, most mobile handheld devices have relatively poor web browsing capability because of the small bandwidth of wireless connection, the small speed of CPU, the small capacity of RAM and Flash ROM, the small display size of LCD and the short lifecycle of battery. Users have to endure bigger communication latency than Desk PC's one because of these factors. In this paper, we propose an effective pre-refresh mechanism for handheld device's embedded web browser so as to make user's web surfing faster. The experiment was done using the simulator designed by ourselves and the experiment result demonstrates the proposed mechanism has a good performance to make web surfing faster.
Qiang Li,Li Zhang,Wanhua Li,Xiaolin Li,Wenli Huang,Hua Yang,Linyong Zheng 한국식품과학회 2016 Food Science and Biotechnology Vol.25 No.1
Tricholoma matsutake is a commercially important edible fungus. Volatile compounds, chemical compositions, and nutritional values of fruiting bodies at different stages of maturity from different geographical areas were analyzed. The main volatile compounds in T. matsutake fruiting bodies were (E)-2-octenal, phenylacetaldehyde, 3-octanone, methyl cinnamate, benzaldehyde, and 1- octen-3-ol. Kinds and levels of volatile compounds from different geographical areas varied. As the fruiting bodies aged, levels of methyl cinnamate and 1-octen-3-ol gradually declined. Potassium was the most abundant element in T. matsutake fruiting bodies. Of 17 amino acids detected in fruiting bodies, glutamate was the most abundant. Volatile compounds, chemical compositions, and nutritional values of T. matsutake varied with age and geographical origin and can serve as chemical indicators for classication of T. matsutake from different geographical areas and at different stages of maturity.
Han Li,Hua Cao,Rong‑pei Yu,Zhen Miao,Ji‑hua Wang,Su‑Ping Qu,Qiang Yuan,Shenchong Li 한국원예학회 2018 Horticulture, Environment, and Biotechnology Vol.59 No.3
Paphiopedilum pacific shamrock is an orchid with high ornamental value. Understanding the mechanisms responsible for leaf color in albino mutants is important for ornamental development and breeding. In this study, we compared the leaf photosynthetic pigment content and transcriptome of albino mutants ppa01 and wild-type P. pacific shamrock. Photosynthetic pigment in mutants was less than 2% of the wild type and chl a/b was 60% less than the wild type. Transcriptome sequencing yielded 6.27 Gb and 5.67 Gb clean data from the mutant and wild-type leaves, respectively. De novo assembly yielded 104,763 unigenes with 15,400 greater than 1 kb in length. In unigene expression analysis, 3170 differentially expressed genes (DEGs) were identified with 2231 (70.38% of total DEGs) down-regulated. Results from GO and KEGG enrichment analysis, KEGG pathway analysis and qPCR suggest that the reduction of chloroplast biosynthesis and division in the mutant was due to low expression levels of ppGLK1 and ppFtsz. Mutants were associated with fewer chloroplasts in leaf cells, abnormal chloroplast structures, impaired chlorophyll biosynthesis, and thus reduced total chlorophyll and carotenoid contents. Furthermore, down-regulated expression of ppNYC1 reduced transformation of chlorophyll b into chlorophyll a, leading to a chl a/b decline. The research will guide future studies of leaf pigment mutations and the breeding of P. pacific shamrock.
Fen-Qiang Li,Jun Zhao,Jian-Hua Mo,Jian-Jun Li,Liang Huang 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.3
In order to reveal the high-velocity deformation mechanisms of Ti-6Al-4V titanium alloy sheets, the dynamic deformation behavior and the microstructure evolutions were compared with those under quasi-static case employing Scanning electron microscopy/Electron back-scattered diffraction (SEM/EBSD) and Transmission electron microscopy (TEM). The results indicated that the distribution of microhardness was uneven. The cause was determined to be the non-uniform material flow and dynamic loading. The grain sizes of the Ti-6Al-4V titanium alloy sheet were nearly the same under two conditions, but the grains were elongated under the dynamic loading compared with that observed in quasi-static forming. In high-velocity bulging, dislocation slip was the principle mechanism of plastic deformation of Ti-6Al-4V titanium alloy when deformation was small. As the strain increased, the twinning phenomenon was activated in addition to the dislocation cell structure. The twinning plane was determined to be the (10 11) plane.
Hai-Long Li,Yi-Hua An,Han Zhang,Hua Huang,Zhen-Qiang Liu,Yan-Bing Li,Hao Yu 한국분자세포생물학회 2013 Molecules and cells Vol.35 No.5
Artificial extracellular matrices play important roles in the regulation of stem cell behavior. To generate materials for tissue engineering, active functional groups, such as amino, carboxyl, and hydroxyl, are often introduced to change the properties of the biomaterial surface. In this study, we chemically modified coverslips to create sur-faces with different amino densities and investigated the adhesion, migration, and differentiation of neural stem cells (NSCs) under serum-free culture conditions. We observed that a higher amino density significantly promoted NSCs attach-ment, enhanced neuronal differentiation and promoted excitatory synapse formation in vitro. These results indicate that the amino density significantly affected the biological behavior of NSCs. Thus, the density and impact of functional groups in extracellular matrices should be considered in the research and development of materials for tissue engineering.
( Zhen Zhen Lian ),( Xiao Jing Yin ),( Hua Li ),( Li Li Jia ),( Xiu Zhen He ),( Yong Bo Yan ),( Nai Hua Liu ),( Ka Yiu Wan ),( Xiao Kun Li ),( Shao Qiang Lin ) 대한피부과학회 2014 Annals of Dermatology Vol.26 No.1
Background: Diabetic wounds are a major clinical challenge, because minor skin wounds can lead to chronic, unhealed ulcers and ultimately result in infection, gangrene, or even amputation. Studies on bone marrow derived mesenchymal stem cells (BMSCs) and a series of growth factors have revealed their many benefits for wound healing and regeneration. Platelet-rich plasma (PRP) may improve the environment for BMSC development and differentiation. However, whether combined use of BMSCs and PRP may be more effective for accelerating diabetic ulcer healing remains unclear. Objective: We investigated the efficacy of BMSCs and PRP for the repair of refractory wound healing in a diabetic rat model. Methods: Forty-eight rats with diabetes mellitus induced by streptozotocin were divided into four groups: treatment with BMSCs plus PRP, BMSCs alone, PRP alone, phosphate buffered saline. The rate of wound closure was quantified. A histopathological study was conducted regarding wound depth and the skin edge at 7, 14, and 28 days after surgery. Results: Wound healing rates were significantly higher in the BMSC plus PRP group than in the other groups. The immunohistochemistry results showed that the expression of platelet/endothelial cell adhesion molecule 1, proliferating cell nuclear antigen, and transforming growth factor-β1 increased significantly in the BMSC plus PRP group compared to the other treatment groups. On day 7, CD68 expression increased significantly in the wounds of the BMSC plus PRP group, but decreased markedly at day 14 compared to the controls. Conclusion: The combination of BMSCs and PRP aids diabetic wound repair and regeneration. (Ann Dermatol 26(1) 1∼10, 2014)