Bulk Synthesis of Fe3Al Intermetallic Compound Nanoparticles by Flow-Levitation Method

Shan-Jun Chen,Song Li,Yang-En Wang,Hui Zeng,Yong-Jian Tang,Wei-Guo Sun,Yan Chen 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.1

Metallic nanopowders have an increasing application in magnetic materials, catalysts and chemical and metallic industries. In this research, a novel bulk synthesis method for preparing high pure intermetallic Fe3Al nanoparticles was developed by flow-levitation (FL) method. The Fe and Al vapors ascending from the high-temperature levitated droplet were condensed by cryogenic argon gas under atmospheric pressure. X-ray diffraction (XRD) and selected-area electron diffraction (SAED) were used to identify and characterize the prepared nanopowders exhibiting a Fe3Al phase. Measurement of transmission electron microscopy (TEM) indicated that the Fe3Al particles are nearly spherical, and the particle size of the compound ranges from 10 nm to 200 nm in diameter. The chemical composition of the nanoparticles were determined with energy dispersive spectrometer. The magnetic properties of the nanopowder indicate that Fe3Al intermetallic compound is a soft magnet at room temperature, with coercivity of 24.2 Oe and saturation magnetization of 173.2 emu/g. The production rate of Fe3Al nanoparticles was estimated to be about 4 g/h in a continuous manner, by using the FL method. This method as great potential in mass production of Fe3Al nanoparticles.

Microstructure Distribution and Grain Coarsening Model of GCr15 Steel in the Laser Surface Treatment

Jin‑shan Chen,Zhen‑xing Li,Ya‑jie Chu,Jie Chen, Xin‑jun Shen 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.10

The GCr15 steel was subjected to laser surface treatment using a diode laser with rectangular spot. Based on the simulatedtemperature field, the microstructure distribution of the laser hardened layer was analyzed, and an empirical equation wasproposed to predict the peak temperature at different depths. The results indicated that with the decrease of depth, the peaktemperature increased exponentially, and the peak temperature at different depths was approximately linear with the powerdensity and the reciprocal of square root of scanning speed. High peak temperature led to the coarsening of grain and thesignificant dissolution of cementite near the surface of hardened layer. At the deeper position of hardened layer, the prioraustenite grain size decreased slightly due to high nucleation rate. The cementite dissolution and coarsening occurred simultaneouslynear the surface, and the cementite dissolution process was postponed due to the significant enrichment of Cr nearthe interface of austenite and cementite. Additionally, an empirical model about grain coarsening was established, which canbe used to predict the prior austenite grain size near the surface during the laser surface treatment.

Expression of Connexin 43 and E-cadherin Protein and mRNA in Non-small Cell Lung Cancers in Chinese Patients

Zhao, Jun-Qiang,Sun, Fang-Jie,Liu, Shan-Shan,Yang, Jun,Wu, Yu-Quan,Li, Gui-Shan,Chen, Qing-Yong,Wang, Jia-Xiang Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.2

Aim: Connexin 43 (Cx43) and E-cadherin are important biomarkers related with cancer. Their expression at protein and mRNA levels was here investigated in 50 primary lung carcinoma tissues and 20 samples of adjacent normal tissue of Chinese patients with non-small cell lung cancer (NSCLC). Methods: Protein and mRNA expression were evaluated by ABC immunohistochemistry and RT-PCR. Results: (1) The positive expression rates of Cx43 and E-cadherin protein were higher in the adjacent normal tissues than those in the primary lung carcinoma tissues; (2) the positive expression rates of Cx43 and E-cadherin protein decreased with NSCLC progression; (3) the expression of E-cadherin protein was not related with the pathological type of NSCLC; and (4) the relative quantity of the Cx43 or E-cadherin mRNA expression was correlated with the the histological type, clinical stage, cancer cell differentiation and the lymph node metastasis. Conclusion: The data suggested that the Cx43 and E-cadherin are reduced with NSCLC progression, and might be important biomarkers for judging the metastasis and prognosis.

Applying Fluorescent Whitening Agent and Tinting Dye on Paper

왕리준(Li-Jun Wang),안국헌(Fu-Shan Chen),Chen Fu-Shan(Kook-Hun An),윤병호(Byung-Ho Yoon) 한국펄프·종이공학회 2004 한국펄프·종이공학회 학술발표논문집 Vol.2004 No.11

A new experimental technique on the tubular joints of spatial grid structures

Chen, Zhi-Hua,Sun, Guo-Jun,Luo, Zhi-Shan Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.40 No.6

A new experimental technique was developed on the plate-inserted welded tubular joints of spatial grid structures. In the experimental technique, a microcomputer controlling instrument of moire intervention (MCIMI) was adopted. A test was designed on the plate-inserted welded tubular joints of spatial grid structures to show the effectiveness of the MCIMI technique. Both traditional electrical measuring technique and MCIMI technique were employed in the test. The test results showed that the MCIMI technique was feasible in the case of the complicated tests on steel structures. The MCIMI technique not only implemented the limitation of traditional electrical measuring technique, but also improved the accuracy of the test. According to the test results, we further examined the plate-inserted welded tubular joints in the cable-stayed spatial grids of the Binhai International Convention & Exhibition in Tianjin, China. The analysis showed the joints are safely designed with adequate conservatism. The research provided a new application of MCIMI in the field of large-scale structure engineering.

Multi-field coupling finite element analysis for determining the influence of temperature field on die service life during precision-forming process of steel synchronizer ring

Jun Zhao,Shan-Ming Luo,Feng-Qiang Li,Chen-Bing Xu 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.7

Failure analysis shows that increased die temperature caused by severe plastic deformation of material and heat conduction between hot billet and cavity significantly affects the distortion of gear cavity in steel synchronizer ring forging process. The forging process of steel synchronizer ring and die temperature distribution under different forging conditions are analyzed through finite element method. Simulation results show that severe plastic deformation occurs in the gear cavity. The improvement of lubrication condition results in decreased die temperature. When the initial billet temperature is high, the die temperature is also high. Increasing forging speed in a certain range facilitates the die temperature decrease. The distribution of die temperature in synthetic forming technology is more reasonable than that of one step forging. The synthetic forming technology is adopted in production to reduce the effects of severe plastic deformation caused by die temperature. The ejection mechanism and control system of the double disc friction press are improved to reduce the contact time between the hot billet and cavity. Experimental results show that synthetic forming technology is reasonable, and that the die service life is prolonged.

Synthesis of pore-expanded mesoporous materials using waste quartz sand and the adsorption effects of methylene blue

Jun-Ming Hong,Bing Lin,Jie-Shan Jiang,Bor-Yann Chen,Chang-Tang Chang 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

Mesoporous material Q-MCM and EX-Q-MCM were synthesized using waste quartz (99.9% SiO2) sand as a silicon source via the sol–gel method. The silicon source was extracted from the waste quartz sand using the hydrothermal method. This study selected methylene blue as a target dye to investigate the dye adsorption performance onto the EX-Q-MCM. The effects on adsorption performance under different initial dye concentrations and different pH values were also studied. The results show that the maximum adsorption capacity was 96.9 mg g 1 and a high pH is favorable for adsorption. Further, equilibrium isotherms of the adsorption of methylene blue on EX-Q-MCM are well described by the Freundlich model. It reveals that the adsorption of methylene blue onto the Q-MCM is a multilayer adsorption.

Analysis of non-point and point source pollution load in DongPieHong Ditch

Shan, Yu,Chen, Jun,Jin, Jie,Song, YongLian,Liu, Jun,Wu, DongBiao,Wu, Ke Urban Science Institute 2019 도시과학 Vol.8 No.2

In this study, the DongPieHong Ditch were taken as the research object, five sampling points were set to measure the COD, NH₃-N,TNandTPindexes. The correlation and principal component analysis were used to judge the main pollution sources and calculate pollution contribution rate. According to the population in the basin, the load of point source pollution into the river was estimated. As a result, the load of COD, NH₃-N and TP into the river was 323.04t/a, 43.8t/a and 3.9t/a, respectively. According to the statistics of the rainfall in the basin, the concentrations of COD, TP and NH₃-N in the initial rainwater were measured and calculated for non-point source pollution, and the results shown that the inflow loads of COD, NH₃-N and TP into the river were 34.59t/a, 0.12t/a and 0.71t/a, respectively. It was found that the main cause of the pollution in the east flash flood gully was point source pollution, and the proportions of COD, NH₃-N and TP into the river were 90.33%, 99.72% and 84.61%, respectively.

C1420T Polymorphism of Cytosolic Serine Hydroxymethyltransferase and Risk of Cancer: a Meta-analysis

Zhong, Shan-Liang,Zhang, Jun,Hu, Qing,Chen, Wei-Xian,Ma, Teng-Fei,Zhao, Jian-Hua Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.5

A series of studies have explored the role of cytosolic serine hydroxymethyltransferase (SHMT1) C1420T polymorphism in cancer risk, but their results were conflicting rather than conclusive. To derive a more precise estimation of the association between C1420T and cancer risk, the present meta-analysis of 28 available studies with 15,121 cases and 18,023 controls was conducted. The results revealed that there was no significant association between the polymorphism and cancer risk overall. In stratified analysis by cancer type (breast cancer, gastrointestinal cancer, leukemia, lymphoma, and others), the results showed that 1420T allele was associated with decreased risk in leukemia (CT vs. CC: OR= 0.825, 95% CI =0.704-0.966; and CT+TT vs. CC: OR= 0.838, 95% CI = 0.722-0.973), but the same results were not present for other cancer types. When subgroup analysis was performed by source of control (population-based [PB] and hospital-based [HB]), a borderline inverse association was observed for the HB subgroup (CT vs. CC: OR= 0.917, 95% CI = 0.857-0.982) but not for the PB subgroup. Stratifying by geographic area (America, Asia and Europe), significant inverse association was only found in Asia subgroup (CT vs. CC: OR= 0.674, 95% CI = 0.522-0.870). In summary, the findings suggest that SHMT1 C1420T polymorphism is not associated with overall cancer development, but might decrease cancer susceptibility of Asians as well as reduce leukemia risk. Large well-designed epidemiological studies will be necessary to validate the risk identified in the current meta-analysis.

Parkinson’s Disease with Fatigue: Clinical Characteristics and Potential Mechanisms Relevant to α-Synuclein Oligomer

Li-Jun Zuo,Shu-Yang Yu,Fang Wang,Yanghui Xia,Ying-Shan Piao,Yang Du,Teng-Hong Lian,Rui-Dan Wang,Qiu-Jin Yu,Ya-Jie Wang,Xiao-Min Wang,Piu Chan,Sheng-Di Chen,Yongjun Wang,Wei Zhang 대한신경과학회 2016 Journal of Clinical Neurology Vol.12 No.2

Background and Purpose The aim of this study was to identify the clinical characteristics and potential mechanisms relevant to pathological proteins in Parkinson’s disease (PD) patients who experience fatigue. Methods PD patients (n=102) were evaluated using a fatigue severity scale and scales for motor and nonmotor symptoms. The levels of three pathological proteins—α-synuclein oligomer, β-amyloid (Aβ)1-42, and tau—were measured in 102 cerebrospinal fluid (CSF) samples from these PD patients. Linear regression analyses were performed between fatigue score and the CSF levels of the above-listed pathological proteins in PD patients. Results The frequency of fatigue in the PD patients was 62.75%. The fatigue group had worse motor symptoms and anxiety, depression, and autonomic dysfunction. The CSF level of α-synuclein oligomer was higher and that of Aβ1-42 was lower in the fatigue group than in the non-fatigue group. In multiple linear regression analyses, fatigue severity was significantly and positively correlated with the α-synuclein oligomer level in the CSF of PD patients, after adjusting for confounders. Conclusions PD patients experience a high frequency of fatigue. PD patients with fatigue have worse motor and part nonmotor symptoms. Fatigue in PD patients is associated with an increased α-synuclein oligomer level in the CSF