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      • KCI등재

        Experimental study and numerical simulation on springback of Ti-6Al-4V alloy under hot U-bending

        Fen-Qiang Li,Jishuai Jiang,Juemei Wang,Jinguo Wang,Xinyu Chen 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.7

        In this study, springback of Ti-6Al-4V sheet subjected to hot bending was investigated experimentally and by numerical simulation. The experiment determined the relative effects of forming temperature, forming speed and holding time on springback during hot bending of the alloy sheet. Distribution of temperature and equivalent stress fields experienced during hot bending were predicted by thermal-mechanical coupling numerical simulation. Analysis of the mutual influence of deformation and temperature was conducted using finite element modeling in DYNAFORM software. The results indicated that increased forming temperature, forming speed and holding time each reduced springback to a degree. Forming temperature had the greatest influence in limiting springback, followed by forming speed and holding time, the latter of which was of minor significance. The thermomechanical coupling numerical model is reliable and the predicted temperature field distribution was confirmed.

      • KCI등재

        Optimization of the Field Shaper Parameters in Electromagnetic Pulse Crimping of Cable

        Fen-Qiang Li,Jishuai Jiang,Hongsong Cheng,Jianling Xu,Xiaohong Ge,Hui Li,Jun Zhao,Yang Ran 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.10

        Crimping of wires to achieve a secure connection is one of the most critical challenges in fabrication of electronic circuit boards, automobiles, aviation, satellite and communication components. The electromagnetic pulse crimping process offers great potential to successfully address these challenges. In this paper, ANSYS/Multi physical software was used to first determine the electromagnetic force distribution on the terminal lug by analyzing the magnetic field in the electromagnetic pulse crimping process. The electromagnetic force was then imported into the ABAQUS/Explicit software as the boundary condition to calculate the deformation behavior of the terminal lug barrel and cable according to the stress–strain curve of the terminal material under high strain rate. The calculated deformation result was subsequently verified by experimental data. Three main parameters of the field shaper were analyzed to determine their influence on the crimping result; slit position, the inner diameter vertical dimension and the position relationship between the terminal lug and field shaper. Then using the empirical formula we calculated and verified the inner diameter vertical dimension of the field shaper. The model proved to be reliable. Deformation of the terminal was determined to be uneven along the circumference in the crimping area. For the type of terminal lug studied, an inner diameter vertical dimension of 10 mm proved to be optimum for increased strength of the crimped terminal connection. Allowing the terminal to protrude 1 mm from the field shaper resulted in a flatter crimped area and significant improvement in the quality of the crimped barrel surface. The empirical formula for calculating the inner diameter vertical dimension of the field shaper is reasonable and reliable, and the calculated measurement resulted in improved connection strength. The results of this research can be used to guide the electromagnetic pulse crimping of other terminal lug and cable types.

      • KCI등재

        Comparative study of the microstructure of Ti-6Al-4V titanium alloy sheets under quasi-static and high-velocity bulging

        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.

      • KCI등재

        Parameter optimization of electromagnetic pulse compaction driven by aluminum tube for tungsten copper powder

        Fen-Qiang Li,Juehao Ding,Miao Zheng,Jianlin Xu,Xiaohong Ge,Hui Li,Jun Zhao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.7

        A combination of multi-physics numerical simulation and experiment was conducted to study the magnetic pulse compaction technology driven by two aluminum tubes of tungsten copper powder. Then, the effects of different process parameters on the density and uniformity of the compact were studied by tuning the thickness of the pack and driver tubes and the gap between them. Results show that the density of compact is the highest when the thickness of the driver tube is 1.0 mm. More energy is consumed for force conduction as the thickness of the pack tube increases. Thus, the density of the compact is the highest when the thickness of the packer tube is 0.8 mm. The speed of the driver tube impacting the pack tube also increases with the rise in the gap. Accordingly, the compaction density with the gap of 1.5 mm is the highest under the same other parameters.

      • Association of Single Nucleotide Polymorphisms in the Prostaglandin-endoperoxide Synthase 2 (PTGS2) and Phospholipase A<sub>2</sub> Group IIA (PLA2G2A) Genes with Susceptibility to Esophageal Squamous Cell Carcinoma

        Liu, Fen,Wei, Wen-Qiang,Cormier, Robert T.,Zhang, Shu-Tian,Qiao, You-Lin,Li, Xin-Qing,Zhu, Sheng-Tao,Zhai, Yan-Chun,Peng, Xiao-Xia,Yan, Yu-Xiang,Wu, Li-Juan,He, Dian,He, Yan Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.4

        Background: The prostaglandin-endoperoxide synthase 2 (PTGS2) and phospholipase A2 group IIA (PLA2G2A) genes encode enzymes that are involved in arachidonic acid and prostaglandin biosynthesis. Dysregulation of both genes is associated with inflammation and carcinogenesis, including esophageal squamous cell carcinoma (ESCC). We therefore hypothesized that there is an association between single nucleotide polymorphisms (SNPs) in these genes and susceptibility to ESCC. Methods: We performed a gene-wide tag SNP-based association study to examine the association of SNPs in PTGS2 and PLA2G2A with ESCC in 269 patients and 269 healthy controls from Taihangshan Mountain, Henan and Hebei Provinces, the rural area of China which has the highest incidence of esophageal cancer in the world. Thirteen tag SNPs in PLA2G2A and 4 functional SNPs in PTGS2 were selected and genotyped using a high-throughput Mass Array genotyping platform. Results: We found a modest increased risk of ESCC in subjects with the PTGS2 rs12042763 AA genotype (OR=1.23; 95% CI, 1.00-3.04) compared with genotype GG. For PLA2G2A, a decreased risk of ESCC was observed in subjects with the rs11677 CT (OR=0.51, 95%CI, 0.29-0.85) or TT genotype (OR=0.51, 95%CI, 0.17-0.96) or the T carriers (CT+TT) (OR=0.52, 95%CI, 0.31-0.85) when compared with the CC genotype. Also for PLA2G2A, rs2236771 C allele carriers were more frequent in the control group (P=0.02). Subjects with the GC (OR=0.55, 95%CI, 0.33-0.93) or CC genotype (OR=0.38, 95% CI, 0.16-0.94) or the C carriers (GC+CC) (OR=0.52, 95%CI, 0.32-0.85) showed a negative association with ESCC susceptibility. Conclusions: Our results suggest that PTGS2 and PLA2G2A gene polymorphisms may modify the risk of ESCC development.

      • Anti-proliferative Effects of Atractylis lancea (Thunb.) DC. via Down-regulation of the c-myc/hTERT/Telomerase Pathway in Hep-G2 Cells

        Guo, Wei-Qiang,Li, Liang-Zhi,He, Zhuo-Yang,Zhang, Qi,Liu, Jia,Hu, Cui-Ying,Qin, Fen-Ju,Wang, Tao-Yun Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.11

        Atractylis lancea (Thunb.) DC. (AL), an important medicinal herb in Asia, has been shown to have anti-tumor effects on cancer cells, but the involved mechanisms are poorly understood. This study focused on potential effects and molecular mechanisms of AL on the proliferation of the Hep-G2 liver cancer cell line in vitro. Cell viability was assessed by MTT test in Hep-G2 cells incubated with an ethanol extract of AL. Then, the effects of AL on apoptosis and cell cycle progression were determined by flow cytometry. Telomeric repeat amplification protocol (TRAP) assays was performed to investigate telomerase activity. The mRNA and protein expression of human telomerase reverse transcriptase (hTERT) and c-myc were determined by real-time RT-PCR and Western blotting. Our results show that AL effectively inhibits proliferation in Hep-G2 cells in a concentrationand time-dependent manner. When Hep-G2 cells were treated with AL after 48h,the $IC_{50}$ was about 72.1 ${\mu}g/mL$. Apoptosis was induced by AL via arresting the cells in the G1 phase. Furthermore, AL effectively reduced telomerase activity through inhibition of mRNA and protein expression of hTERT and c-myc. Hence, these data demonstrate that AL exerts anti-proliferative effects in Hep-G2 cells via down-regulation of the c-myc/hTERT/telomerase pathway.

      • KCI등재

        Comparison of Forage Quality, Productivity and β-carotene Content according to Maturity of Forage Rye (Secale cereale L.)

        Zhao, Guo Qiang,Wei, Sheng Nan,Li, Yan Fen,Jeong, Eun Chan,Kim, Hak Jin,Kim, Jong Geun The Korean Society of Grassland and Forage Science 2020 한국초지조사료학회지 Vol.40 No.3

        These experiments were to investigate the variations of rye on forage quality, productivity and β-carotene concentration affected by maturity in Pyeongchang region. Limited information are available about how forage quality and β-carotene content are affected by various factors. Samples were collected from rye harvested every 5 days, from April 25 to May 31 (April 25, April 30, May 4, May 9, May 15, May 21, May 25 and May 31). Dry matter (DM) content, plant height, DM yield and total digestible nutrient (TDN) yield increased continuously with the progressed maturity. However, crude protein (CP) content, in vitro dry matter digestibility (IVDMD) and relative feed value (RFV) decreased markedly with the delay of harvesting, while TDN content decreased from April 25 till May 15, then followed by a stable fluctuation. Conversely, acid detergent fiber (ADF) and neutral detergent fiber (NDF) value increased and then fluctuated slightly after blooming stage. For quality of plant parts, stem contained the lowest CP content and RFV value, and the highest ADF and NDF contents compared with other parts, while the grain showed the higher CP, IVDMD, RFV and lower fiber contents than others. With the plant matured, leaf proportion decreased while stem and grain proportion increased, and feed value of all the three parts decreased till blooming stage and followed by a stable phase. β-carotene concentration showed its highest on jointing stage, and then fell down sharply on the sequential stages. In conclusion, harvest around May 15 (blooming) is proper for forage rye if directly consumed by livestock as green chop in Pyeongchang under the consideration of both nutritive yield and forage quality.

      • SCIESCOPUSKCI등재

        Changes in fermentation pattern and quality of Italian ryegrass (Lolium multiflorum Lam.) silage by wilting and inoculant treatments

        Liu, Chang,Zhao, Guo Qiang,Wei, Sheng Nan,Kim, Hak Jin,Li, Yan Fen,Kim, Jong Geun Asian Australasian Association of Animal Productio 2021 Animal Bioscience Vol.34 No.1

        Objective: This study was conducted to investigate the effects of wilting and microbial inoculant treatment on the fermentation pattern and quality of Italian ryegrass silage. Methods: Italian ryegrass was harvested at heading stage and ensiled into vinyl bags (20 cm×30 cm) for 60d. Italian ryegrass was ensiled with 4 treatments (NWNA, no-wilting noadditive; NWA, no-wilting with additive; WNA, wilting no-additive; WA, wilting with additive) in 3 replications, wilting time was 5 hours and additives were treated with 106 cfu/g of Lactobacillus plantarum. The silages samples were collected at 1, 2, 3, 5, 10, 20, 30, 45, and 60 days after ensiling and analyzed for the ensiling quality and characteristics of fermentation patterns. Results: Wilting treatment resulted in lower crude protein and in vitro dry matter digestibility and there were no significant differences in acid detergent fiber (ADF), total digestible nutrient (TDN), water-soluble carbohydrate (WSC), ammonia content, and pH (p>0.05). However, wilting treatment resulted in higher ADF and neutral detergent fiber content of Italian ryegrass silage (p<0.05), and the WNA treatment showed the lowest TDN and in vitro dry matter digestibility. The pH of the silage was higher in the wilting group (WNA and WA) and lower in the additive treatment group. Meanwhile, the decrease in pH occurred sharply between the 3-5th day of storage. The ammonia nitrogen content was significantly lower in the additive treatment (p<0.05), and wilting had no effect. As fermentation progressed, the lactic and acetic acid contents were increased and showed the highest content at 30 days of storage. Conclusion: The wilting treatment did not significantly improve the silage fermentation, but the inoculant treatment improved the fermentation patterns and quality of the silage. So, inoculation before ensiling is recommended when preparing high quality of Italian ryegrass silage, and when wilting, it is recommended to combine inoculation for making high quality silage.

      • Overexpression of Phospholipase A<sub>2</sub> Group IIA in Esophageal Squamous Cell Carcinoma and Association with Cyclooxygenase-2 Expression

        Zhai, Yan-Chun,Dong, Bin,Wei, Wen-Qiang,He, Yan,Li, Xin-Qing,Cormier, Robert T.,Wang, Wei,Liu, Fen Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.21

        Background: Esophageal cancer is one of the most frequently occurring malignancies and the seventh leading cause of cancer-related deaths in the world. The esophageal squamous cell carcinoma (ESCC) is the most common histological type of esophageal cancer worldwide. Materials and Methods: Our goal in this study was to detect phospholipase A2 Group IIA (PLA2G2A) and cyclooxygenase-2 (COX-2) immuno-expression in ESCC in a high-risk population in China. Results: Positive expression of PLA2G2A protein was observed in 57.2% (166/290) of the cases, while COX-2 was found in 257 of 290 samples (88.6%), both PLA2G2A and COX-2 being expressed in 153 cases (52.8%), with a significant agreement (Kappa=0.091, p=0.031).Overexpression of PLA2G2A was significantly correlated with the depth of invasion (p=0.001). Co-expression of PLA2G2A and COX-2 not only significantly correlated with the depth of invasion (p=0.004) but also with TNM stage (p=0.04). Conclusions: Our results showed that in patients with ESCC, PLA2G2A overexpression and PLA2G2A co-expression with COX-2 is significantly correlated with advanced stage. The biological role and pathophysiologic regulation of PLA2G2A and COX-2 overexpression in ESCC deserve further investigation.

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