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result(s) for
"Heo, Jung Ho"
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Effect of Slag Composition on Dephosphorization and Foamability in the Electric Arc Furnace Steelmaking Process: Improvement of Plant Operation
2021
The effect of slag composition under M’O (monoxide, M = Fe,Mg) saturation and fully liquid conditions on dephosphorization and slag foamability was evaluated in an electric arc furnace (EAF) steelmaking plant operation by considering thermodynamics and phase equilibria. It was confirmed that M’O saturation slag is more favorable for higher dephosphorization than fully liquid slag due to its high activity of CaO as a thermodynamic driving force. As a quantitative measure of slag foamability, the foaming index was clearly dependent on the temperature and slag composition. Moreover, foam stability was evaluated by applying the predominance stability diagram based on phase equilibria. Consequently, it can be suggested that an efficient direction for dephosphorization and slag foaming during the EAF process is to generate high CaO activity as well as small amounts of M’O monoxide and dicalcium silicate (Ca2SiO4) compounds.
Journal Article
Effect of CaO Addition on Iron Recovery from Copper Smelting Slags by Solid Carbon
by
Park, Joo Hyun
,
Kim, Byung-Su
,
Heo, Jung Ho
in
Applied sciences
,
Carbon
,
Characterization and Evaluation of Materials
2013
We investigated the effect of flux (lime) addition on the reduction behavior of iron oxide in copper slag by solid carbon at 1773 K (1500 °C). In particular, we quantified the recovery of iron by performing typical kinetic analysis and considering slag foaming, which is strongly affected by the thermophysical properties of slags. The iron oxide in the copper slag was consistently reduced by solid carbon over time. In the kinetic analysis, we determined mass transfer coefficients with and without considering slag foaming using a gas holdup factor. The mass transfer of FeO was not significantly changed by CaO addition when slag foaming was ignored, whereas the mass transfer of FeO when slag foaming was considered was at a minimum in the 20 mass pct CaO system. Iron recovery, defined as the ratio of the amount of iron clearly transferred to the base metal ingot to the initial amount of iron in the slag phase before reduction, was maximal (about 90 pct) in the 20 mass pct CaO system. Various types of solid compounds, including Mg
2
SiO
4
and Ca
2
SiO
4
, were precipitated in slags during the FeO reduction process, and these compounds strongly affected the reduction kinetics of FeO as well as iron recovery. Iron recovery was the greatest in the 20 mass pct CaO system because no solid compounds formed in this system, resulting in a highly fluid slag. This fluid slag allowed iron droplets to fall rapidly with high terminal velocity to the bottom of the crucible. A linear relationship between the mass transfer coefficient of FeO considering slag foaming and foam stability was obtained, from which we concluded that the mass transfer of FeO in slag was effectively promoted not only by gas evolution due to reduction reactions but also by foamy slag containing solid compounds. However, the reduced iron droplets were finely dispersed in foamy and viscous slags, making actual iron recovery a challenge.
Journal Article
Manganese Recovery by Silicothermic Reduction of MnO in BaO-MnO-MgO-CaF2 (-SiO2) Slags
2018
The effects of reducing agent, CaF2 content, and reaction temperature upon the silicothermic reduction of MnO in the BaO-MnO-MgO-CaF2 (-SiO2) slags were investigated. Mn recovery was proportional to Si activity in the molten alloy. Moreover, 90 pct yield of Mn recovery was obtained under 5 mass pct CaF2 content and 1873 K (1600 °C) reaction temperature. Increasing CaF2 content above 5 pct yielded little or no further increase in Mn recovery, because it was accompanied by increased slag viscosity owing to the precipitation of high melting point compounds such as Ba2SiO4.
Journal Article
Observations of FeO Reduction in Electric Arc Furnace Slag by Aluminum Black Dross: Effect of CaO Fluxing on Slag Morphology
by
Park, Joo Hyun
,
Sahajwalla Veena
,
Heo Jung Ho
in
Aluminosilicates
,
Aluminothermic reactions
,
Aluminothermic reduction
2020
The effect of CaO fluxing on slag morphology was investigated during the reduction of FeO in electric arc furnace slag by aluminum black dross (ABD). Macro- and microscopic observations, by evaluating entrapped gas bubbles and reduced iron droplets related to gas evolution, apparent slag morphologies, and vertical section of slag at different initial CaO contents and reaction times, confirmed that both aluminothermic (dominant reaction) and carbothermic (minor) reduction occurred. Thus, the production of CO(+CO2) gas caused swelling-shrinking phenomena with repeated expansion and collapse of the slag pellet. In addition, macroscopic observation of slag morphologies as a function of the initial CaO content is well associated with quantitative consideration of the apparent viscosity as well as spinel ([Mg,Fe]Al2O4) activity. Consequently, appropriate CaO fluxing is necessary to control the composition of highly fluid slag by changing the slag from a high-alumina system to calcium–aluminosilicate melts when utilizing ABD as a reducing agent.
Journal Article
Long-term efficacy and safety of moderate-intensity statin with ezetimibe combination therapy versus high-intensity statin monotherapy in patients with atherosclerotic cardiovascular disease (RACING): a randomised, open-label, non-inferiority trial
by
Kim, Byeong-Keuk
,
Lee, Seung-Jun
,
Hong, Soon Jun
in
Anticholesteremic Agents - adverse effects
,
Arteriosclerosis
,
Atherosclerosis
2022
Drug combinations rather than increasing doses of one drug can achieve greater efficacy and lower risks. Thus, as an alternative to high-intensity statin monotherapy, moderate-intensity statin with ezetimibe combination therapy can lower LDL cholesterol concentrations effectively while reducing adverse effects. However, evidence from randomised trials to compare long-term clinical outcomes is needed.
In this randomised, open-label, non-inferiority trial, patients with atherosclerotic cardiovascular disease (ASCVD) at 26 clinical centres in South Korea were randomly assigned (1:1) to receive either moderate-intensity statin with ezetimibe combination therapy (rosuvastatin 10 mg with ezetimibe 10 mg) or high-intensity statin monotherapy (rosuvastatin 20 mg). The primary endpoint was the 3-year composite of cardiovascular death, major cardiovascular events, or non-fatal stroke, in the intention-to-treat population with a non-inferiority margin of 2·0%. This trial is registered with ClinicalTrials.gov, NCT03044665 and is complete.
Between Feb 14, 2017, and Dec 18, 2018, 3780 patients were enrolled: 1894 patients to the combination therapy group and 1886 to the high-intensity statin monotherapy group. The primary endpoint occurred in 172 patients (9·1%) in the combination therapy group and 186 patients (9·9%) in the high-intensity statin monotherapy group (absolute difference −0·78%; 90% CI −2·39 to 0·83). LDL cholesterol concentrations of less than 70 mg/dL at 1, 2, and 3 years were observed in 73%, 75%, and 72% of patients in the combination therapy group, and 55%, 60%, and 58% of patients in the high-intensity statin monotherapy group (all p<0·0001). Discontinuation or dose reduction of the study drug by intolerance was observed in 88 patients (4·8%) and 150 patients (8·2%), respectively (p<0·0001).
Among patients with ASCVD, moderate-intensity statin with ezetimibe combination therapy was non-inferior to high-intensity statin monotherapy for the 3-year composite outcomes with a higher proportion of patients with LDL cholesterol concentrations of less than 70 mg/dL and lower intolerance-related drug discontinuation or dose reduction.
Hanmi Pharmaceutical.
Journal Article
Comparison of efficacy and safety between third‐dose triple and third‐dose dual antihypertensive combination therapies in patients with hypertension
by
Kim, Weon
,
Rha, Seung‐Woon
,
Hong, Soon Jun
in
Amlodipine
,
Antihypertensive Agents - adverse effects
,
Antihypertensives
2023
We compared the efficacy and safety of third‐standard‐dose triple and third‐standard‐dose dual antihypertensive combination therapies in patients with mild to moderate hypertension. This was a phase II multicenter, randomized, double‐blind, parallel‐group trial. After a 4‐week placebo run‐in period, 245 participants were randomized to the third‐dose triple combination (ALC group; amlodipine 1.67 mg + losartan potassium 16.67 mg + chlorthalidone 4.17 mg) or third‐dose dual combination (AL group; amlodipine 1.67 mg + losartan potassium 16.67 mg, LC group; losartan potassium 16.67 mg + chlorthalidone 4.17 mg, AC group; amlodipine 1.67 mg + chlorthalidone 4.17 mg) therapy groups and followed up for 8 weeks. The mean systolic blood pressure (BP) reduction was ‐18.3 ± 13.2, ‐13.0 ± 13.3, ‐16.3 ± 12.4, and ‐13.8 ± 13.2 mmHg in the ALC, AL, LC, and AC groups, respectively. The ALC group showed significant systolic BP reduction compared to the AL and AC groups at weeks 4 (P = .010 and P = .018, respectively) and 8 (P = .017 and P = .036, respectively). At week 4, the proportion of systolic BP responders was significantly higher in the ALC group (42.6%) than in the AL (22.0%), LC (23.3%), and AC (27.1%) groups (P = .013, P = .021, and P = .045, respectively). At week 8, the proportion of systolic and diastolic BP responders was significantly higher in the ALC group (59.7%) than in the AL (39.3%) and AC (42.4%) groups (P = .022 and P = .049, respectively) at week 8. Third‐standard‐dose triple antihypertensive combination therapy demonstrated early effective BP control compared to third‐standard‐dose dual combination therapies, without increasing adverse drug reactions in patients with mild‐to‐moderate hypertension.
Journal Article
Use of Industrial Waste (Al-Dross, Red Mud, Mill Scale) as Fluxing Agents in the Sulfurization of Fe-Ni-Cu-Co Alloy by Carbothermic Reduction of Calcium Sulfate
by
Jeong, Eui Hyuk
,
Park, Joo Hyun
,
Jung Ho Heo
in
Calcium sulfate
,
Carbothermic reactions
,
Dross
2018
The use of industrial waste [mill scale (MS), red mud (RM), Al-dross (AD)] as fluxing agents in the sulfurization of Fe-Ni-Cu-Co alloy to matte (Fe-Ni-Cu-Co-S) by carbothermic reduction of CaSO4 was investigated at 1673 K (1400 °C). The sulfurization efficiency (SE) was 76 (± 2) pct at RM or AD single fluxing. However, SE drastically increased to approximately 89 pct at a ‘5AD + 5MS’ combination, which was equivalent to reagent-grade chemical ‘5Al2O3 + 5Fe2O3’ fluxing (SE = 88 pct). The present results can be used to improve the cost-effective recovery of rare metals (Ni and Co) from deep sea manganese nodules.
Journal Article
Attenuation of Acetylcholine Activated Potassium Current (IKACh) by Simvastatin, Not Pravastatin in Mouse Atrial Cardiomyocyte: Possible Atrial Fibrillation Preventing Effects of Statin
by
Zhang, Yin Hua
,
Lee, Su-Jin
,
Kim, Kyoung-Lyoung
in
Acetylcholine
,
Acetylcholine - pharmacology
,
Action potential
2014
Statins, 3-hydroxy-3-methyl-glutaryl-CoA reductase inhibitors, are associated with the prevention of atrial fibrillation (AF) by pleiotropic effects. Recent clinical trial studies have demonstrated conflicting results on anti-arrhythmia between lipophilic and hydrophilic statins. However, the underlying mechanisms responsible for anti-arrhythmogenic effects of statins are largely unexplored. In this study, we evaluated the different roles of lipophilic and hydrophilic statins (simvastatin and pravastatin, respectively) in acetylcholine (100 µM)-activated K+ current (IKACh, recorded by nystatin-perforated whole cell patch clamp technique) which are important for AF initiation and maintenance in mouse atrial cardiomyocytes. Our results showed that simvastatin (1-10 µM) inhibited both peak and quasi-steady-state IKACh in a dose-dependent manner. In contrast, pravastatin (10 µM) had no effect on IKACh. Supplementation of substrates for the synthesis of cholesterol (mevalonate, geranylgeranyl pyrophosphate or farnesyl pyrophosphate) did not reverse the effect of simvastatin on IKACh, suggesting a cholesterol-independent effect on IKACh. Furthermore, supplementation of phosphatidylinositol 4,5-bisphosphate, extracellular perfusion of phospholipase C inhibitor or a protein kinase C (PKC) inhibitor had no effect on the inhibitory activity of simvastatin on IKACh. Simvastatin also inhibits adenosine activated IKACh, however, simvastatin does not inhibit IKACh after activated by intracellular loading of GTP gamma S. Importantly, shortening of the action potential duration by acetylcholine was restored by simvastatin but not by pravastatin. Together, these findings demonstrate that lipophilic statins but not hydrophilic statins attenuate IKACh in atrial cardiomyocytes via a mechanism that is independent of cholesterol synthesis or PKC pathway, but may be via the blockade of acetylcholine binding site. Our results may provide important background information for the use of statins in patients with AF.
Journal Article
Effect of Direct Reduced Iron (DRI) on Dephosphorization of Molten Steel by Electric Arc Furnace Slag
2018
We investigated the effect of direct reduced iron (DRI) addition on dephosphorization of molten steel by electric arc furnace (EAF) slag at 1823 K (1550 °C). Various phenomena such as CO gas evolution and slagmaking by gangue oxides in DRI were experimentally observed at each reaction step. Thermodynamic behaviors of phosphorus, oxygen, and carbon were strongly dependent on DRI content. Basicity, which is the thermodynamic driving force of dephosphorization, decreased with the increasing DRI content because SiO2 concentration in the slag was proportional to DRI addition. The excess free energy of P2O5 increased with the increasing SiO2 content in slag. A higher DRI content made dephosphorization difficult by decreasing the basicity and stability of P2O5 in the slag. Therefore, when using DRI in EAF process, it is very important to control the basicity of slag.
Journal Article
Impact of duration and dosage of statin treatment and epicardial fat thickness on the recurrence of atrial fibrillation after electrical cardioversion
by
Cha, Tae-Joon
,
Heo, Jung-Ho
,
Lee, Jae-Woo
in
Aged
,
Atrial Fibrillation - drug therapy
,
Biomedical Engineering and Bioengineering
2015
The purpose of this study was to investigate the time-dependent effect of statin treatment and echocardiographic epicardial fat thickness (EFT) on the maintenance of sinus rhythm (SR) in atrial fibrillation (AF) patients after electrical cardioversion (EC). One hundred sixty-three AF patients without previous statin treatment who underwent EC were consecutively enrolled. The maintenance rate of SR after EC (1, 3, 6, and 12 months) as documented by electrocardiogram and EFT were compared between patients with statin treatment (statin group,
n
= 63) and those without (no statin group,
n
= 100). There was no significant difference in the maintenance rate of SR between the groups soon after EC (statin group; 85.7 % vs. no statin; 84.8 %,
p
= 0.535), after 1 month (71.0 vs. 59.1 %,
p
= 0.091), and after 3 months (63.2 vs. 50.0 %,
p
= 0.086). However, the maintenance rate of SR was significantly higher in the statin group compared to no statin group (61.8 vs. 42.9 %,
p
= 0.024) after 6 months, and this significant difference persisted up to 12 months of follow up (60.1 vs. 36.4 %,
p
= 0.001). Patients with recurrence showed higher baseline EFT (7.4 ± 2.7 vs. 8.5 ± 3.0 mm,
p
= 0.014). Multivariate linear regression analysis indicated that EFT, left atrial diameter, high-density lipoprotein cholesterol, statin treatment, and dose were the significant contributors to the maintenance of SR for all periods after EC. Statin treatment and low EFT were associated with a higher maintenance rate of SR in AF patients after EC. Significant benefit of statin was realized 6 months after EC, and this benefit was shown to be maintained over time.
Journal Article