Dehydrogenation of Alkylaromatics over Supported Vanadium Oxide Catalyst with Carbon Dioxide as soft Oxidant

Hong, Do-Young,Jhung, Sung Hwa,Vislovskiy, V. P.,Chang, Jong-San,Yoo, Jin S.,Park, Sang-Eon,Park, Yeung-Ho 한국공업화학회 2004 응용화학 Vol.8 No.2

Over V-Sb-O/Al₂O₃ catalyst, substantially higher (~ 20 - 60% in relative) conversions of initial hydrocarbons and yields of corresponding alkenylbenzenes have been achieved under the dehydrogenation of ethylbenzene, iso- and n-propylbenzenes, 1,4-diethylbenzene and 4-ethyltoluene in the presence of carbon dioxide, compared to those in inert atmosphere, due to promotional oxidative functions of CO₂ to alleviate the dehydrogenation equilibrium as well as to maintain V-sites in active oxidation state, V^(5+).

Performance of CZTSSe thin film solar cells fabricated using a sulfo-selenization process: Influence of the Cu composition

Chalapathy, R.B.V.,Gang, Myeng Gil,Hong, Chang Woo,Kim, Ji Hun,Jang, Jun Sun,Yun, Jae Ho,Kim, Jin Hyeok Elsevier 2018 SOLAR ENERGY -PHOENIX ARIZONA THEN NEW YORK- Vol.159 No.-

<P><B>Abstract</B></P> <P>In this work, earth-abundant CZTSSe thin film solar cells were fabricated by sulfo-selenization of the Mo/Zn/Cu/Sn/Cu metallic precursors. The influences of morphological and compositional properties of the absorbers on performance of solar cells were investigated by tuning Cu content in the films. The Raman analysis showed that absorbers consist of a kesterite CZTSSe phase with ZnSe as a minor secondary phase. X-ray photoelectron spectroscopy (XPS) analyses revealed that the surfaces are Cu depleted and Zn enriched compared with the bulk composition of the absorbers. The results indicate that during sulfo-selenization the Cu diffused into the film and the Zn towards the film surface. The performance of the solar cells initially improved with the increasing of the Cu content and then decreased. By tuning the Cu content in the absorbers, the minority-carrier life time improved from 0.8 to 1.6 ns. The power conversion efficiency increased from 5.1 to 8.03% with fine controlling of Cu composition of the CZTSSe absorbers. The diode-ideality factors are higher than 2, suggesting an increased interfacial recombination in the devices. The high ideality-factors A and low minority carrier life times may originate from surface and bulk related defects, which in turn limits the V<SUB>oc</SUB> and the achievable high conversion efficiency for the CZTSSe thin film solar cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CZTSSe thin film solar cells were fabricated by sulfo-selenization of sputtered metallic Mo/Zn/Cu/Sn/Cu precursors. </LI> <LI> The surface composition of the absorbers was Cu depleted and Zn rich compared to the bulk of the absorbers. </LI> <LI> The ideality factors ‘A’ over 2 suggest that increased interface recombination in the devices which reduced the open circuit voltage of the devices. </LI> <LI> By tuning the Cu content in the absorbers solar cells with conversion efficiency about 8.03% was obtained. And the best efficiency of 8.17% was achieved without an antireflection coating. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Molecular basis involved in the blocking effect of antidepressant metergoline on C-type inactivation of Kv1.4 channel

Bai, Hyoung-Woo,Eom, Sanung,Yeom, Hye Duck,Nguyen, Khoa V.A.,Lee, Jaeeun,Sohn, Sung-Oh,Lee, Jun-Ho Elsevier 2019 NEUROPHARMACOLOGY - Vol.146 No.-

<P><B>Abstract</B></P> <P>Voltage-gated potassium channels (VGKCs) are transmembrane ion channels specific for potassium. Currently there are nine kinds of VGKCs. Kv1.4 is one of shaker-related potassium channels. It is a representative alpha subunit of potassium channels that can inactivate A type-currents, leading to N pattern inactivation. Inactivation of Kv channels plays an important role in shaping electrical signaling properties of neuronal and muscular cells. The shape of N pattern inactivation can be modified by removing the N-terminal (NT) domain which results in non-inactivated currents and C pattern inactivation. In a previous work, we have reported the regulatory effect of metergoline on Kv1.4 and Nav1.2 channel activity. In the present study, we constructed a mutant of deleted 61 residues from NT of Kv1.4 channels (Kv1.4 Δ2-61) and found that it induced an outward peak and steady-state currents We also studied the modulation effect of metergoline on the activity of this Kv1.4 Δ2-61 mutant channel without having the N-terminal quick inactivation domain. Our results revealed that treatment with metergoline inhibited NT deleted Kv1.4 mutant channel activity in a concentration-dependent manner which was reversible. Interestingly, metergoline treatment induced little effects on the outward peak current in the deleted Kv1.4 mutant channel. However, metergoline treatment conspicuously inhibited steady state currents of Kv1.4 Δ2-61 channels with acceleration current mode. The acceleration of steady-state current of deleted Kv1.4 mutant channel occurred in a concentration-dependent manner. This means that metergoline can accelerate C pattern inactivation of Kv1.4 Δ2-61 channel by acting as an open state dependent channel blocker. We also performed site-directed mutations in V561A and K532Y, also known as C-type inactivation sites. V561A, K532Y, and V561A + K532Y substitution mutants significantly attenuated the acceleration effect of metergoline on C pattern inactivation of hKv1.4 channel currents. In docking modeling study, predicted binding residues for metergoline were analyzed for six amino acids. Among them, the K532 residue known as the C-type inactivation site was analyzed to be a major site of action. Then various mutants were constructed. K532 substitution mutant significantly abolished the effect of metergoline on Kv1.4 currents among various mutants whereas other changes had slight inhibitory effects. Furthermore, we found that metergoline had specificity for Kv1.4, but not for Kv1.5 currents. In addition, the A type current in rat neuronal cell was inhibited and accelerated of inactivation. This result further shows that metergoline might interact with Lys532 residue and then accelerate C pattern inactivation of Kv1.4 channels with channel type specificity. Taken together, these results demonstrate the molecular basis involved in the effect of metergoline, an ergot alkaloid, on human Kv1.4 channel, providing a novel interaction ligand.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Metergoline, ergot-derived psychoactive drug, produced inhibition on steady state current of Kv1.4 channel currents. </LI> <LI> Treatment of metergoline on Kv1.4 Δ2-61 channel currents produced significant inhibitions of the non-inactivating plateau than peak currents. </LI> <LI> Metergoline interacted predominantly with residues at channel pore region of Kv1.4 channel. </LI> <LI> Metergoline is more selective for Kv1.4 channels and is shown the effects as open channel blocker. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Palladium/Single-Walled Carbon Nanotube Back-to-Back Schottky Contact-Based Hydrogen Sensors and Their Sensing Mechanism

Zhang, Miluo,Brooks, Lauren L.,Chartuprayoon, Nicha,Bosze, Wayne,Choa, Yong-ho,Myung, Nosang V. American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.1

<P>A Schottky contact-based hydrogen (H<SUB>2</SUB>) gas sensor operable at room temperature was constructed by assembling single-walled carbon nanotubes (SWNTs) on a Si/SiO<SUB>2</SUB> substrate bridged by Pd microelectrodes in a chemiresistive/chemical field effect transistor (chemFET) configuration. The Schottky barrier (SB) is formed by exposing the Pd–SWNT interfacial contacts to H<SUB>2</SUB> gas, the analyte it was designed to detect. Because a Schottky barrier height (SBH) acts as an exponential bottleneck to current flow, the electrical response of the sensor can be particularly sensitive to small changes in SBH, yielding an enhanced response to H<SUB>2</SUB> gas. The sensing mechanism was analyzed by <I>I–V</I> and FET properties before and during H<SUB>2</SUB> exposure. <I>I–V</I><SUB><I>sd</I></SUB> characteristics clearly displayed an equivalent back-to-back Schottky diode configuration and demonstrated the formation of a SB during H<SUB>2</SUB> exposure. The <I>I–V</I><SUB><I>g</I></SUB> characteristics revealed a decrease in the carrier mobility without a change in carrier concentration; thus, it corroborates that modulation of a SB via H<SUB>2</SUB> adsorption at the Pd–SWNT interface is the main sensing mechanism.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-1/am404328g/production/images/medium/am-2013-04328g_0008.gif'></P>

Effects of dopant (Al, Ga, and In) on the characteristics of ZnO thin films prepared by RF magnetron sputtering system

Kyu Ung Sim,신승욱,A.V. Moholkar,문종하,Jae Ho Yun,김진혁 한국물리학회 2010 Current Applied Physics Vol.10 No.3

The un-doped and Al, Ga, and In doped (3 wt.%) ZnO thin films have been prepared on glass substrates using RF magnetron sputtering at 350 ℃. The effects of these dopants on the structural, morphological,electrical, and optical properties of deposited films have been studied. XRD study showed that all doped ZnO thin films have the polycrystalline nature with hexagonal wurtzite phase having c-axis preferred out-of-plane orientation. The cross-sectional FE-SEM micrographs showed that all the films have columnar structure. AFM images showed that doped ZnO thin films have better surface smoothness than undoped ZnO thin films regardless of doping elements. The GZO thin film have the optimal electrical properties among all doped samples in terms of the carrier concentration (6.13 × 1023 cm-3), charge carrier mobility (28.2 ㎠ V-1 s-1), and a minimum resistivity (3.61 × 10-4 Ω cm). UV–Vis spectrometer results showed that all the films are highly transparent in the visible region and the band gap energy of the films varies from 3.25 eV to 3.75 eV for the different dopants. PL spectra showed the un-doped and doped ZnO thin film exhibited a violet emission in the 390–405 nm range, with different intensities, which is due to difference in concentration of zinc vacancies.

Cervical cancer patient reported gastrointestinal outcomes: intensity/ volumetric modulated vs. 3D conformal radiation therapy

Ryan Urban,Justin Wong,Peter Lim,Susan Zhang,Ingrid Spadinger,Robert Olson,Francois Bachand,Clement Ho,Anna V. Tinker,Lovedeep Gondara,Sarah Nicole Hamilton 대한부인종양학회 2022 Journal of Gynecologic Oncology Vol.33 No.5

Objective: To evaluate gastrointestinal (GI) patient reported outcomes (PROs) in cervical cancer patients treated with definitive radiotherapy (RT), comparing 3D conformal RT (3DCRT) vs. intensity modulated/volumetric modulated arc therapy (IMRT/VMAT). Methods: An analysis of patients treated with definitive RT between 2015–2018 was performed. GI PROs were prospectively collected at baseline, during RT (acute), ≤12 weeks after RT (subacute), and >12 weeks after RT (late). GI PROs evaluated three symptom domains: bowel problems (BPs), bowel bother (BB), and abdominal problems (APs). Multiple linear regression analysis was performed to investigate associations between mean changes of symptom scores with clinical and dosimetric variables. Results: The cohort included 167 patients. A total of 100 (60%) patients were treated with IMRT/VMAT and 67 (40%) with 3DCRT. In the subacute phase, the mean change of symptom scores from baseline in 3DCRT vs. IMRT/VMAT were +0.9 vs. −1.15 (p=0.004) for BP, +2.18 vs. −0.10 (p=0.019) for BB, and +1.41 vs. −0.38 (p=0.021) for AP. Likewise, in the late phase, mean changes were +0.72 vs. −0.82 (p=0.014) for BP, +1.98 vs. −0.03 (p=0.008) for BB, and +1.29 vs. −0.31 (p<0.001) for AP. On multiple linear regression, use of 3DCRT vs. IMRT/VMAT was associated with greater mean changes in subacute BP (p=0.023) and late phase AP (p=0.019). A higher small bowel V50Gy was associated increased symptom scores in late AP (p=0.012). Conclusion: 3DCRT was associated with significantly greater worsening of GI PRO symptom scores in the subacute and late phase. These data support the ongoing use of IMRT/VMAT in routine practice

Original Article : Nutritional Value and Bioactive Properties of Enzymatic Hydrolysates prepared from the Livers of Oncorhynchus keta and Oncorhynchus gorbuscha (Pacific Salmon)

( Ho Dong Yoon ),( Ekaterina P Karaulova ),( Lilia V Shulgina ),( Evgeni V Yakush ),( Jong Soo Mok ),( Su Seon Lee ),( Cheng Liang Xie ),( Jeong Gyun Kim ) 한국수산과학회(구 한국수산학회) 2015 Fisheries and Aquatic Sciences Vol.18 No.1

Calculated chemical scores (computed in relation to the FAO/WHO reference protein) for salmon liver protein hydrolysates indicated that all amino acids (other than methionine and threonine) were present in adequate or excess quantities; thus, the raw liver material is a good source of essential amino acids. The hydrophobic amino acids contents in hydrolysates prepared from Oncorhynchus keta and O. gorbuscha were 38.4 and 39.1%, respectively. The proportion of released peptides exceeding 500 kDa was reduced when hydrolysates were treated with the commercial enzyme Alcalase, although proportions in the following MW ranges were elevated: 100.500 kDa and <50 kDa. The optimal conditions for enzymatic hydrolysis were as follows: pH 7.0, 50°C, and a reaction time of 1 h. Of the different proteases tested, Alcalase was the most efficient for production of salmon liver hydrolysate with the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity. The hydrolysates prepared from salmon liver had a balanced amino acid composition. The liver protein hydrolysates contained low molecular weight peptides, some of which may be bio-active; this bio-active potential should be investigated. Inhibition of the DPPH radical increased with increased degree of hydrolysis (DH), regardless of protease type. DPPH radical scavenging abilities, antithrombotic effects and α-glucosidase enzyme inhibition effects of O. keta liver hydrolysate increased in a dose-dependent manner. Thus, salmon liver hydrolysate may be useful in functional food applications and as a source of novel products.

Phenol decomposition in water cathode of DC atmospheric pressure discharge in air

Ho Suk Choi,Vladimir V. Rybkin,Elena S. Bobkova,Dmitriy S. Krasnov,Alexandra V. Sungurova 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.5

We studied phenol decomposition in aqueous solution under the action of DC discharge at atmospheric pressure in air. The decomposition efficiency was 0.017 molecules per 100 eV. When the kinetics of forming destruction products was studied in detail, the peculiarities of air plasma action were revealed for the first time. Plasma action not only results in the formation of oxygen-containing products, which are usually formed under oxygen plasma action (hydroxyhenols, carboxylic acids, aldehydes), but also the formation of nitro phenols. The treatment is accompanied by hydrogen peroxide formation, a pH decrease, and nitric and nitrous acids formation. We also discussed the possible mechanism of the processes and the role of some active species in chemical transformations after determining some parameters of the discharge.

Heat pipes with variable thermal conductance property for space applications

V. Kravets,Ye. Alekseik,O. Alekseik,S. Khairnasov,V. Baturkin,T. Ho,L. Celotti 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.6

The activities presented in this paper demonstrate a new approach to provide passive thermal control using heat pipes, as demonstrated on the electronic unit of DLR’s MASCOT lander, which embarked on the NEA sample return mission Hayabusa 2 (JAXA). The focus is on the development and testing of heat pipes with variable thermal conductance in a predetermined temperature range. These heat pipes act as thermal switches. Unlike standard gasloaded heat pipes and thermal-diode heat pipes construction of presented heat pipes does not include any additional elements. Copper heat pipes with metal fibrous wicks were chosen as baseline design. We obtained positive results by choosing the heat carrier and structural parameters of the wick (i.e., pore diameter, porosity, and permeability). The increase in the thermal conductivity of the heat pipes from 0.04 W/K to 2.1 W/K was observed in the temperature range between −20 °C and +55 °C. Moreover, the heat pipes transferred the predetermined power of not less than 10 W within the same temperature range. The heat pipes have been in flight since December 2014, and the supporting telemetry data were obtained in September 2015. The data showed the nominal operation of the thermal control system.

Critical Behavior of La_0.7Ca_0.3MnO₃ Nanoparticles

Ho, T. A.,Thanh, T. D.,Manh, T. V.,Ho, T. O.,Thang, P. D.,Phan, T. L.,Yu, S. C. The Japan Institute of Metals 2015 Materials transactions Vol.56 No.9