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Journal of Materials Science & Technology 2008年第3期24卷 343-346页

作者： Villando Thursdiyanto eun-jae bae eung-Ryul baek School of Materials Science and Engineering Yeungnam University

A novel process based on centrifugal casting was developed to produce martensitic stainless steel for guideroll materials. Centrifugal casting provides a lower production cost and less of the thermal cracking defects which normally occur in the overlaid welding process. In this study, the effects of Ni on the microstructure and mechanical properties of martensitic stainless steel were investigated. The results show that the addition of Ni resulted in a decrease in the volume fraction of delta ferrite and an increase in the volume fraction of the retained austenite, respectively. Moreover, a tensile strength of 1600 MPa with an elongation of 4% were obtained after tempering at 500℃ for 2 h. These values were higher than those obtained by using the conventional overlaid process.

关键词： Centrifugal casting Martensitic stainless steel Delta ferrite Mechanical properties

Effect of friction on the contact stress of a coated polymer gear

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Friction 2020年第6期8卷 1169-1177页

作者： Su-Min bae Kuk-Jin SEO Dae-eun KIM Department of Mechanical Engineering Yonsei UniversitySeoul 03722Republic of Korea

Polymer gears are used extensively in various ***,durability issues have been emerging because of friction at gear tooth contact *** extend the lifetime of polymer gears,a low-frictional coating has been considered as a possible *** this study,a finite element simulation method was performed to investigate the contact stress between a pair of coated polymer *** simulation included various friction coefficients(COFs)for studying the effects of friction during the *** results revealed that the friction causes the contact stress to shift over the roll angle,which is attributed to the direction of the sliding friction based on a free-body *** also investigated the effects of coating and found that a thin coating has little effect on the bulk deformation behavior of the ***,the stress distribution in the coating at the pitch point was investigated as the COF *** zero friction,three notable stress regions were observed:1)the center of the surface,2)the end of the contact,and 3)the overall contact *** COF was increased in the micro-slip region of the contact interface,both tensile and compressive stresses in the coating *** study provides significant aid to engineers for understanding the stress response of the coating applied to polymer gears to achieve an optimal design.

关键词： coating contact stress finite element method(FEM) friction polymer gear

Relationships between Pathological Patterns and Vocal Qualities Estimated by Acoustic Parameters

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Chinese Journal of Integrative Medicine 2015年第5期21卷 346-354页

作者： Young-jae Park Young-bae Park Department of Diagnosis and Biofunctional Medicine College of Korean MedicineKyung Hee University Department of Diagnosis and Biofunctional Medicine Kyung Hee University Hospital at Gangdong

Objective： To examine whether vocal characteristics estimated by acoustic parameters were associated with phlegm, yin deficiency, or cold-heat patterns. Methods： A total of 75 college students （males：females = 53：22） aged 19-24 years were enrolled in this study. Each subject was asked to complete the phlegm pattern questionnaire （PPQ）, yin deficiency questionnaire （YDQ） and cold-heat questionnaire （CHQ）. For the acoustic analysis, each subject was asked to produce a sustained vowel sound （/a/） for 3 s to be used to calculate acoustic parameters. Then, habitual fundamental frequency （F0）, jitter, shimmer, F0 tremor, mean F0, standard deviation of F0, maximum F0, minimum F0, normalized noise energy, harmonic-to-noise ratio, signal-to-noise ratio, amplitude tremor, and power ratio were calculated using the Dr. Speech software. Finally, four hierarchical regression models with pattern questionnaire scores as dependent variables were formed to examine which factors among acoustic parameters, sex, and age were predictive of those pattern scores. Results： PPQ, YDQ, heat, and cold pattern scores all formed significant regression model equations and the adjusted R2 values were 0.281, 0.164, 0.156, and 0.170, respectively. There were aging effects in the PPQ and YDQ models （standardized β =0.199, 0.271, respectively）. Vocal tremor-related Fo tremor and vocal ringing-related power ratio parameters were associated with PPQ and YDQ scores. Gender was directly predictive of PPQ and indirectly moderated the relationship between power ratio and YDQ score. Vocal pitch- related habitual F0 and mean F0 were associated with heat and cold scores. These results indicate that the vocal qualities of phlegm- and yin deficiency-susceptible subjects tend to be ringing and less tremorous, and those of heat- and cold-susceptible subjects tend to be high-pitched. Conclusion： Our study results suggest that vocal characteristics estimated by acoustic parameters are partially predictive of phlegm,

关键词： Chinese medicine syndrome oriental medicine acoustic parameters

A feasible route to produce 1.1 GPa ferritic-based low-Mn lightweight steels with ductility of 47%

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Journal of Materials Science & Technology 2022年第22期117卷 225-237页

作者： Kwang Kyu Ko Hyo Ju bae eun Hye Park Hyeon-Uk Jeong Hyoung Seok Park jae Seok Jeong Jung Gi Kim Hyokyung Sung Nokeun Park jae Bok Seol Department of Materials Engineering and Convergence Technology Center for K-metalGyeongsang National University(GNU)Jinju 52828South Korea School of Materials Science and Engineering Yeungnam UniversityGyeongbuk 38541South Korea Materials Research Team R&D Hyundai MobisYongin 16891South Korea Materials Technology Development Team Doosan Heavy Industries&ConstructionChangwon 51711South Korea

High- and medium-Mn (H/M-Mn) base lightweight steels are a class of ultrastrong structural materials with high ductility compared to their low-Mn counterparts with low strength and poor ***, producing these H/M-Mn materials requires the advanced or high-tech manufacturing techniques, which can unavoidably provoke labor and cost concerns. Herein, we have developed a facilestrategy that circumvents the strength–ductility trade-off in low-Mn ferritic lightweight steels, by employing low-temperature tempering-induced partitioning (LTP). This LTP treatment affords a typical Fe-2.8Mn-5.7Al-0.3C (wt.%) steel with a heterogeneous size-distribution of metastable austenite embeddedin a ferrite matrix for partitioning more carbon into smaller austenite grains than into the larger austenite ones. This size-dependent partitioning results in slip plane spacing modification and lattice strain,which act through dislocation engineering. We ascribe the simultaneous improvement in strength andtotal elongation to both the size-dependent dislocation movement in austenite grains and the controlleddeformation-induced martensitic transformation. The low-carbon-partitioned large austenite grains increase the strength and ductility as a consequence of the combined martensitic transformation andhigh dislocation density-induced hardening and by interface strengthening. Additionally, high-carbonpartitioned small austenite grains enhance the strength and ductility by planar dislocation glide (inthe low strain regime) and by cross-slipping and delayed martensitic transformation (in the high strainregime). The concept of size-dependent dislocation engineering may provide different pathways for developing a wide range of heterogeneous-structured low-Mn lightweight steels, suggesting that LTP maybe desirable for broad industrial applications at an economic cost.

关键词： Low-Mn lightweight steel Carbon partitioning Metastable austenite Dislocation movement

Destruction of methylphosphonic acid in a supercritical water oxidation bench-scale double wall reactor

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Journal of Environmental Sciences 2011年第4期23卷 545-552页

作者： Bambang Veriansyah eun-Seok Song jae-Duck Kim Supercritical Fluid Research Laboratory Korea Institute of Science and Technology (KIST) 39-1 Hawolgok-dong Seoungbuk-gu Seoul 136-791 Korea

The destruction of methylphosphonic acid （MPA）, a final product by hydrolysis/neutralization of organophosphorus agents such as sarin and VX （O-ethyl S-[2-（diisopropylamino）ethyl] methylphosphonothionate）, was investigated in a a bench-scale, continuous concentric vertical double wall reactor under supercritical water oxidation condition. The experiments were conducted at a temperature range of 450–600°C and a fixed pressure of 25 MPa. Hydrogen peroxide was used as an oxidant. The destruction efficiency （DE） was monitored by analyzing total organic carbon （TOC） and MPA concentrations using ion chromatography on the liquid effluent samples. The results showed that the DE of MPA up to 99.999% was achieved at a reaction temperature of 600°C, oxygen concentration of 113% storichiometric requirement, and reactor residence time of 8 sec. On the basis of the data derived from experiments, a global kinetic rate equation for the DE of MPA and DE of TOC were developed by nonlinear regression analysis. The model predictions agreed well with the experimental data.

关键词： supercritical water oxidation destruction efficiency methylphosphonic acid reaction kinetic nonlinear regression

Curcumin-induced cell death depends on the level of autophagic flux in A172 and U87MG human glioblastoma cells

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Chinese Journal of Natural Medicines 2020年第2期18卷 114-122页

作者： Lee Jong-eun Yoon Sung Sik Lee jae-Wook Moon eun-Yi Department of Bioscience and Biotechnology Sejong UniversitySeoul 05006Republic of Korea

Glioblastoma is the deadliest neoplasm with the worst 5-year survival rate among all human *** promotes autophagic cell death or blocks the induction of apoptosis in eukaryotic ***,we investigated whether varying levels of autophagic flux in glioblastoma lead to different efficacies of curcumin treatment using U87 MG and A172 human glioblastoma *** number of LC3 puncta,the number of cells with LC3 puncta and the level of LC3 Ⅱ,Atg5 and Atg7 protein were higher in U87 MG cells compared with A172 *** the cells were incubated with curcumin for 24 or 48 h,the percentage of cell death was higher in A172 cells compared with U87 MG *** the level of LC3 was lower,that of curcumin-induced LC3 was higher,in A172 cells than in U87 MG *** relative increases in cell death and LC3-mediated autophagy were greater under serum starvation in A172 cells compared with U87 MG ***-induced A172 cell death was reduced by serum *** both types of cells were transfected with LC3-GFP,the percentage of cell death was higher in A172 cells than that in U87 MG *** together,the data demonstrate that curcumin-mediated tumor cell death is regulated by the basal level of autophagic flux in different glioblastoma *** suggests that prior to the use of various curcumin therapeutics,the level of basal or induced autophagic flux should be carefully examined in tumor cells for the best efficacy.

关键词： Glioblastoma A172 U87MG Autophagic flux Curcumin

Comparison of intra peritoneal anti-adhesive polysaccha rides derived from Phellinus mushrooms in a rat peritonitis model

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World Journal of Gastroenterology 2005年第6期11卷 810-816页

作者： jae-Sung bae Kwang-Ho Jang Hee-Kyung Jin Department of Surgery Department of Laboratory Animal Medicine

AIM: To assess the adhesion- and abscess-reducing capacities of various concentrations of polysaccharides derived from fungus, Phellinus gilvus (PG) or Phellinus linteus (PL) in a rat peritonitis ***: In 96 SD rats, experimental peritonitis was induced using the cecal ligation and puncture model (CLP).Rats were randomly assigned to 8 groups; Ringer's lactate solution (RL group), hyaluronic acid (HA group), 0.025%,0.25%, and 0.5% polysaccharides from PG (PG0.025, 0.25,and 0.5 groups), and PL (PL0.025, 0.25, and 0.5 groups).Adhesions and abscesses were noted at 7 d after ***-PCR assay was performed to assess the cecal ***: Adhesion formation was significantly reduced in PG0.25, 0.5, PL0.25, 0.5, and HA groups (2.5±0.7,2.4±0.7, 3.8±1.0, 3.6±0.8, and 2.7±1.1, P＜0.05). The incidence of abscesses was significantly reduced in all treated groups compared to RL group (58%, P＜0.05). The urokinase-type plasminogen activator (uPA) gene expression was greatly up-regulated by increasing the concentration of polysaccharides. The urokinase-type plasminogen activator receptor (uPAR) and tumor necrosis factor (TNF)-α mRNA were highly expressed in PG0.25, 0.5, PL0.25, and ***: We concluded that 0.5% polysaccharide derived from PG and PL was the optimal concentration in preventing adhesion and abscess formation and may act by modulating activity of uPA and TNF-α in a rat peritonitis model.

关键词： Adhesion Abscess Phellinus gilvus, Phellinus linteus Polysaccharides

Mechanical strength and corrosion resistance of Al-additive friction stir welded AZ31B joints

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Journal of Magnesium and Alloys 2023年第5期11卷 1519-1535页

作者： jae-Yeon Kim eun-Woo Kim Dong-O Kim eun-Kyo Ju Ji-eun Lee jaeheon Lee Jai-Won Byeon Mining Engineering Department Colorado School of MinesGoldenCO 80401USA Department of Materials Science and Engineering Seoul National University of Science and TechnologySeoul 01811Republic of Korea

Compared to other structural alloys,magnesium alloys have a relatively poor corrosion resistance and low mechanical strength,which can be further deteriorated when these alloys are subjected to joining processes using the existing joining ***,we propose for the first time an additive friction stir-welding(AFSW)using fine Al powder as an additive to improve the mechanical strength as well as corrosion resistance of AZ31B weld *** is a solid-state welding method of forming a high-Al AZ31B joint via an in-situ reaction between pure Al powders filled in a machined groove and the AZ31B *** optimize the process parameters,AFSW was performed under different rotational and transverse speeds,and number of passes,using tools with a square or screw *** particular,to fabricate a weld zone,where the Al was homogenously dispersed,the effects of the groove shape were investigated using three types of grooves:surface one-line groove,surface-symmetric grooves,and inserted symmetric *** homogenous and defect-less AFS-welded AZ31B joint was successfully fabricated with the following optimal parameters:1400 rpm,25 mm/min,four passes,inserted symmetric grooves,and the tool with a square *** AFSW fully dissolved the additive Al intoα-Mg and in-situ precipitated Mg_(17)Al_(12)particles,which was confirmed via scanning electron microscopy,transmission electron microscope,and X-ray diffraction *** microhardness,joint efficiency,and elongation at the fracture point of the AFS-welded AZ31B joint were 80 HV,101%,and 8.9%,*** values are higher than those obtained for the FS-welded AZ31 joint in previous *** corrosion resistance of the AFS-welded AZ31B joint,evaluated via hydrogen evolution measurements and potentiodynamic polarization tests,was enhanced to 55%relative to the FS-welded AZ31B joint.

关键词： AZ31B magnesium alloy Additive friction stir-welding In-situ reaction Mg_(17)Al_(12)particles Joint efficiency Corrosion resistance

Multi-faceted small molecule for Alzheimer’s disease

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Neural Regeneration Research 2023年第10期18卷 2198-2199页

作者： Min Hee Park Hee Kyung Jin jae-sung bae KNU Alzheimer’s Disease Research Institute Department of PhysiologySchool of MedicineKyungpook National UniversityDaeguSouth Korea KNU Alzheimer’s Disease Research Institute Department of Laboratory Animal MedicineCollege of Veterinary MedicineKyungpook National UniversityDaeguSouth Korea

The main pathologies of Alzheimer’s disease(AD)are the accumulation of amyloid-B(AB)and tau ta ngles,and these two fundamental pathologies accompany the va rious neuropathological features,such as neuroinfla mmation,... 详细信息

关键词： Alzheimer tau amyloid

Surgical Repair of Ventricular Septal Defect in Neonates: Indications and Outcomes

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Congenital Heart Disease 2024年第1期19卷 69-83页

作者： jae Hong Lee Sungkyu Cho jae Gun Kwak Hye Won Kwon Woong-Han Kim Mi Kyoung Song Sang-Yun Lee Gi Beom Kim eun Jung bae Department of Thoracic and Cardiovascular Surgery Research Institute for Convergence of Biomedical Science and TechnologyPusan National University Yangsan HospitalYangsanKorea Department of Thoracic and Cardiovascular Surgery Seoul National University Children’s HospitalSeoulKorea Department of Pediatrics Seoul National University Children’s HospitalSeoulKorea

Background:The optimal surgical timing and clinical outcomes of ventricular septal defect(VSD)closure in neo-nates remain *** aimed to evaluate the clinical outcomes of VSD closure in neonates(age≤30 days).Methods:We retrospectively reviewed 50 consecutive neonates who underwent VSD closure for isolated VSDs between August 2003 and June *** for the procedure included congestive heart failure/failure to thrive and pulmonary *** adverse events(MAEs)were deﬁned as the composite of all-cause mortality,reoperation,persistent atrioventricular block,and signiﬁcant(≥grade 2)valvular ***:The median age and body weight at operation were 26.0 days(interquartile range[IQR],18.8–28.3)and 3.7 kg(IQR,3.3–4.2),*** median follow-up duration was 110.4 months(IQR,56.8–165.0).Seven patients required preoperative respiratory support,andﬁve had signiﬁcant(≥grade 2)preoperative valvular *** early mortality occurred due to irreversible cardiogenic shock;no late mortality was *** reopera-tion was due to hemodynamically signiﬁcant residual VSD at 103.8 months *** overall survival,freedom from reoperation,and freedom from MAE at 15-years were 98.0%,96.3%,and 94.4%,***-operative mechanical ventilation was associated with a longer duration of postoperative mechanical ventilation(p<0.001)and a longer length of intensive care unit stay(p<0.001).Conclusions:VSD closure with favorable outcomes without morbidities is feasible even in ***,neonates requiring preoperative respiratory support may require careful postoperative management considering the long-term postoperative ***,surgical VSD closure might be indicated earlier in neonates with respiratory compromise.

关键词： Ventricular septal defect neonate early surgery neonatal surgery