Influence of processing parameters on warpage according to the Taguchi experiment

Guojian Zheng,Weiguo Dong,Qian Wang,Xiangyu Guo 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.10

An automotive triangle trim was chosen as a research model, and the influence of processing parameters was determined with the Taguchiexperimental method. An L27 (313) orthogonal array was constructed to investigate the significance of each factor (mold temperature,melt temperature, injection time, V/P switchover, packing pressure, and packing time). The computer-aided engineering softwareMoldflow was employed to determine the extent of warpage. The influence of processing parameters was analyzed by obtaining the signal-to-noise ratio and by conducting a range analysis. Furthermore, the processing parameters for minimizing warpage were optimized. Subsequently, the optimization packing condition for warpage minimization based on the filling conditions.

The Effect of Na0.44MnO2 Formation in Na+-Modified Spinel LiMn2O4

Lilong Xiong,Youlong Xu,Weiguo Wu,Pei Lei,Tao Tao,Xin Dong 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.4

Na0.44MnO2 impure phase is formed during the synthetic process of Na+-modified spinel LiMn2O4 by solid state reaction which is confirmed by x-ray diffraction analysis. Scanning electron microscopy, transmission electron microscopy and galvanostatic charge-discharge measurements are carried out to investigate the effect of the formation of Na0.44MnO2 impurity on the morphology and electrochemical properties of the spinel material. The results show that the spinel material with impure phase exhibits improved cyclability compared to that of the pristine LiMn2O4. The improved electrochemical performance is mainly ascribed to the improved crystallinity of the spinel particles, enhanced stability of the spinel structure and good electronic conductivity of the composite.

Formation and failure characteristics of a landslide induced by excavation in western Henan, China

Haining Liu,Suzhen Duan,Han Dong Liu,Weiguo Wang,Yujie Jia 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.7

Engineering construction in mountainous areas is a key factor inducing slope failure, whichposes severe threats to life and property safety during construction and operation. Thus, clearunderstanding of slope structure and potential failure mechanisms is of great importance forslope reinforcement. The Shangge landslide, located in a mountainous area of WesternHenan, China, was triggered by excavation along a toll station. The slope was still unstableafter a row of anti-sliding piles were constructed. To clarify the deformation characteristics andfailure mechanism of this landslide and provide reinforcement guidance for slopes with similargeological conditions, a combined method of field investigation, displacement monitoring,and numerical simulation was employed. The results indicate that the natural slope comprisesa dual structure of soil and rock, and that the soil, with poor permeability and high watermoisture, was prone to form a potential sliding surface. Secondly, slope excavation was thedirect triggering factor. Lastly, but most importantly, the preliminary investigation work failed toaccurately expose the potential position of the sliding surface, and the existing anti-slide pilesfailed to cross the potential sliding surface, which made them unable to effectively improveslope stability. The numerical simulation verified that the recommended piles installed on theplatform of level 2 could significantly improve slope stability. Therefore, when carrying outengineering slope design in similar geological environments, the slope structure and materialcomposition should be fully identified, and the influence of groundwater on the slope stabilitystate should be emphasized. These results can provide a reference for similar slopereinforcement designs.

Compressive Deformation Behavior of AZ31Mg Alloy Containing {10–12} Extension Twins at Different Temperature

Hua Zhang,Xiaoqing Bai,Minjian Hou,Lifei Wang,Qiang Zhang,Jianfeng Fan,Weiguo Li,Hongbiao Dong,Bingshe Xu 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.5

Influence of pre-introducing {10–12} extension twins on compressive deformation behavior of AZ31Mg alloy at differenttemperature was investigated. The compression tests were conducted along the normal direction of AZ31Mg alloy at roomtemperature, 100 °C, 200 °C and 300 °C with a strain rate of 1 × 10−3 s−1. The results indicated that the pre-introducing{10–12} extension twins strongly affected the yield strength, the peak strength and the strain hardening rate at middle-lowtemperature (≤ 200 °C). The twinned samples containing pre-introducing {10–12} extension twins exhibited smaller yieldstrength and larger peak strength than the as-received samples without {10–12} extension twins at temperature ≤ 200 °C. Forthe as-received samples, the strain hardening rate decreased gradually at different temperature. While for the twinned samples,the strain hardening behavior exhibited three distinct stages at temperature ≤ 200 °C. When compressing at 300 °C, the asreceivedand twinned samples exhibited similar compression flow curves and strain hardening rate curves. The continuousdynamic recrystallization (CDRX) was the main dynamic recrystallization (DRX) mechanism in the as-received sample whencompressing at 200 °C. The twin assisted DRX besides CDRX was also initiated in the twinned sample when compressingat 200 °C. While the DRX mechanism was transformed into the discontinuous dynamic recrystallization (DDRX) in boththe as-received and twinned samples when compressing at 300 °C.

Cyclooxygenase-2 Polymorphisms and Susceptibility to Colorectal Cancer: A Meta-Analysis

Jun Wang,Xufeng Guo,Jixiang Zhang,Jia Song,Mengyao Ji,Shijie Yu,Jing Wang,Zhuo Cao,Weiguo Dong 연세대학교의과대학 2013 Yonsei medical journal Vol.54 No.6

Purpose: Four polymorphisms, -765G>C, -1195G>A, 8473T>C, and Val511Ala, in the cyclooxygenase-2 (COX-2) gene were identified to be associated with colorectal cancer (CRC) risk. However, the results are inconsistent. The objective of this meta-analysis was to evaluate the association between these four polymorphisms and the risk of CRC. Materials and Methods: All eligible case-control studies published up to December 2012 on the association between the four polymorphisms of COX-2 and CRC risk were identified by searching PubMed and Web of Science. The CRC risk associated with the four polymorphisms of the COX-2 gene was estimated for each study by odds ratio (OR) together with its 95% confidence interval (CI), respectively. Results: A total of 15 case-control studies were included. Overall, no evidence has indicated that the -1195A allele, -765C allele, 8473C allele, and 511Ala allele are associated with susceptibility to CRC (-1195G>A: OR=1.11, 95% CI: 0.82-1.51, p=0.78; -765G>C: OR=1.08, 95% CI: 0.96-1.21, p=0.07; 8473T>C: OR=1.03, 95% CI: 0.89-1.18, p=0.91; Val511Ala:OR=0.71, 95% CI: 0.46-1.09, p=0.94). However, stratified analysis with ethnicity indicated that individuals with -765GC or GC/CC genotypes had an increased risk of CRC among Asian populations (GC vs. GG: OR=1.05, 95% CI: 0.87-1.28, p=0.03; GC+CC vs. GG: OR=1.08, 95% CI: 0.96-1.21, p=0.07). Conclusion: This meta-analysis indicated that -765G>C polymorphism was significantly associated with susceptibility to CRC in Asian populations.

Fatigue Analysis of 306K Crude Oil Tanker Based on MSC Fatigue

Wei Guo,Dong-Myung Bae,Bo Cao,Da-Long Qi 한국해양공학회 2015 韓國海洋工學會誌 Vol.29 No.6

Fatigue in the metal used as hull material has always been an important issue. The fatigue phenomenongenerally occurs suddenly in a ship hull, and always causesa large number of casualties and economic losses. This paper presents a study of an assessment method for the fatigue life based on Li’s approach using MSC Fatigue. The details of Li’s approach based on MSC Fatigue are provided. Based on the results of this study, it can be concluded that Li’s approach has several advantages: (1) it allows the wide application of different structural details, (2) is easy to use, and (3) provides accurate results. Finally, Li’s approach can be proven to be feasible for a ship’s fatigue analysis.