원자로 기기 열수력 해석 코드에서 붕소 수송 방정식의 구현

박익규(Ik Kyu Park),이승욱(Seung Wook Lee),윤한영(Han Young Yoon) 한국전산유체공학회 2013 한국전산유체공학회지 Vol.18 No.4

The boron transport model has been implemented into the CUPID code to simulate the boron transport phenomena of the PWR. The boron concentration conservation was confirmed through a simulation of a conceptual boron transport problem in which water with a constant inlet boron concentration injected into an inlet of the 2-dimensional vertical flow tube. The step wise boron transport problem showed that the numerical diffusion of the boron concentration can be reduced by the second order convection scheme. In order to assess the adaptability of the developed boron transport model to the realistic situation, the ROCOM test was simulated by using the CUPID implemented with the boron transportation.

원자로 기기 열수력 해석 코드에서 붕소 수송 방정식의 구현

박익규(Ik Kyu Park),이승욱(Seung Wook Lee),윤한영(Han Young Yoon) 한국전산유체공학회 2013 한국전산유체공학회지 Vol.18 No.4

The boron transport model has been implemented into the CUPID code to simulate the boron transport phenomena of the PWR. The boron concentration conservation was confirmed through a simulation of a conceptual boron transport problem in which water with a constant inlet boron concentration injected into an inlet of the 2-dimensional vertical flow tube. The step wise boron transport problem showed that the numerical diffusion of the boron concentration can be reduced by the second order convection scheme. In order to assess the adaptability of the developed boron transport model to the realistic situation, the ROCOM test was simulated by using the CUPID implemented with the boron transportation.

Performance evaluation of polyamide TFC membranes: Effects of free volume properties on boron transport

Kim, Sung-Jo,Han, Doseon,Yu, Hye-Weon,O'Rourke, Brian E.,Kobayashi, Yoshinori,Suzuki, Ryoichi,Hwang, Moonhyun,Kim, In S. Elsevier 2018 Desalination Vol.432 No.-

<P><B>Abstract</B></P> <P>To comprehensively investigate the correlation between free volume properties (size and distribution) in the interior of polyamide (PA) active layer and mass transport mechanism, six polyamide thin film composite (TFC) membranes were characterized using positron annihilation lifetime spectroscopy (PALS). In case of pressurized filtration conditions, the rejection rate of boron across all PA membranes was found to be inversely proportional to the free volume size. The more boron transport occurred at the membrane containing larger free volume. In addition, the transition of the neutral boron transport mechanism from convection to diffusion was found to occur at a membrane free volume radius around 0.275nm within the applied pressure range (2 and 10bar), as verified by PALS and the dimensionless Peclet number. We believe that mass transport mechanism transition from convection to diffusion is caused by the compression of polyamide active layer due to applied hydraulic pressure (10bar), resulting in lowering the convective mass transport pathway inside polyamide active layer. These membrane free volume size criteria and experimental filtration results may subsequently be used as new design guidelines for the development of high boron rejection polyamide TFC membranes having a low energy consumption.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The free volume characterization of several polyamide membranes by PALS were performed to evaluate boron transport. </LI> <LI> The transition of boron transport mechanism was observed at a free volume radius around 0.275nm. </LI> <LI> Free volume properties measured by PALS could be used as new design criteria for high boron rejection membranes. </LI> </UL> </P>

Amino Acid Transporters as Potential Therapeutic Targets in Thyroid Cancer

Keisuke Enomoto,Muneki Hotomi 대한내분비학회 2020 Endocrinology and metabolism Vol.35 No.2

Thyroid cancer cells have a high amino acid demand for proliferation, invasion, and metastasis. Amino acids are taken up by thyroidcancer cells, both thyroid follicular cell and thyroid parafollicular cells (commonly called “C-cells”), via amino acid transporters. Amino acid transporters up-regulate in many cancers, and their expression level associate with clinical aggressiveness and prognosis. This is the review to discuss the therapeutic potential of amino acid transporters and as molecular targets in thyroid cancer.

Highly Conductive Boron Nanotubes: Transport Properties, Work Functions, and Structural Stabilities

Bezugly, Viktor,Kunstmann, Jens,Grundkö,tter-Stock, Bernhard,Frauenheim, Thomas,Niehaus, Thomas,Cuniberti, Gianaurelio American Chemical Society 2011 ACS NANO Vol.5 No.6

<P>The transport properties, work functions, electronic structure, and structural stability of boron nanotubes with different lattice structures, radii, and chiralities are investigated theoretically. As the atomic structure of boron nanotubes and the related sheets is still under debate, three probable structural classes (nanotubes derived from the α-sheet, the buckled triangular sheet, and the distorted hexagonal sheet) are considered. For comparison with recent transport measurements [<I>J. Mater. Chem</I>. <B>2010</B>, <I>20</I>, 2197], the intrinsic conductance of ideal nanotubes with large diameters (<I>D</I> ≈ 10 nm) is determined. All considered boron nanotubes are highly conductive, irrespective of their lattice structures and chiralities, and they have higher conductivities than carbon nanotubes. Furthermore, the work functions of the three sheets and the corresponding large-diameter nanotubes are determined. It is found that the value of the nanotubes obtained from the α-sheet agrees well with the experiment. This indirectly shows that the atomic structure of boron nanotubes is related to the α-sheet. The structural stability of nanotubes with diameters > 2 nm approaches that of the corresponding boron sheets, and α-sheet nanotubes are the most stable ones. However, for smaller diameters the relative stabilities change significantly, and for diameters < 0.5 nm the most stable structures are zigzag nanotubes of the buckled triangular sheet. For structures related to the distorted hexagonal sheet the most stable nanotube is discovered to have a diameter of 0.39 nm.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2011/ancac3.2011.5.issue-6/nn201099a/production/images/medium/nn-2011-01099a_0003.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn201099a'>ACS Electronic Supporting Info</A></P>

Improved transport critical current properties in glycerin-doped MgB₂ wire using milled boron powder and a solid-state reaction of 600 °C

Jun, Byung-Hyuk,Kim, Jung Ho,Kim, Chan-Joong,Choo, Kee Nam Elsevier 2015 Journal of Alloys and Compounds Vol.650 No.-

<P><B>Abstract</B></P> <P>We adopted simultaneously three effects of milling, carbon (C) doping and solid-state reaction to improve critical current properties of MgB<SUB>2</SUB> superconducting wire. The influences of heat-treatment temperature, including a conventional solid–liquid reaction of 650–1000 °C and a solid-state reaction of 600 °C below the melting point (650 °C) of Mg powder, were examined on the transport superconducting properties of <I>in situ</I> powder-in-tube (PIT) processed MgB<SUB>2</SUB>/Fe wires using ball-milled and glycerin-treated boron (B) powder. The aims of the mechanical milling and liquid glycerin treatment of the B powder were to reduce the grain size of the MgB<SUB>2</SUB> and achieve homogeneous C incorporation into the MgB<SUB>2</SUB>, respectively. The superconducting properties of MgB<SUB>2</SUB> wires heat-treated in the range of 650–1000 °C were investigated, and it was also investigated as to whether the C incorporation occurred even in a low-temperature solid-state process of 600 °C, thus resulting in an improvement of the superconducting properties by obtaining both high grain boundary density and C substitution effects. The MgB<SUB>2</SUB> phase formation, actual C substitution amount, full width at half maximum (FWHM), critical temperature (<I>T</I> <SUB>c</SUB>), magnetic field dependence of transport critical current density (<I>J</I> <SUB>c</SUB>) and temperature dependence of the upper critical field (<I>H</I> <SUB>c2</SUB>) were evaluated for glycerin-doped MgB<SUB>2</SUB>/Fe wires fabricated at different heat-treatment temperatures. The glycerin-doped MgB<SUB>2</SUB> wire using milled B powder heat-treated at a solid-state of 600 °C showed the highest transport <I>J</I> <SUB>c</SUB> values at 4.2 K over the entire applied field regime. It was revealed that the grain boundary density was higher and that the C substitution also occurred by a low temperature heat-treatment process, which led to a higher <I>J</I> <SUB>c</SUB>. In addition, a solid–solid diffusion reaction with the pre-treated B powder resulted in poor crystallinity, which enhanced <I>H</I> <SUB>c2</SUB> and improved <I>J</I> <SUB>c</SUB>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> PIT MgB<SUB>2</SUB>/Fe wires were fabricated using ball-milled and glycerin-treated B powder. </LI> <LI> The influences of heat-treatment temperature were investigated. </LI> <LI> We adopted simultaneously 3 effects of milling, C doping and solid-state reaction. </LI> <LI> Transport <I>J</I> <SUB>c</SUB>, <I>H</I> <SUB>c2</SUB> and <I>H</I> <SUB>irr</SUB> of three effects-adopted MgB<SUB>2</SUB> wire could be enhanced. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>We adopted simultaneously three effects of milling, C doping and solid-state reaction to improve critical current properties of <I>in situ</I> PIT processed MgB<SUB>2</SUB> superconducting wire. As a result, the glycerin-doped MgB<SUB>2</SUB> wire using milled B powder heat-treated at a solid-state of 600 °C showed the highest transport <I>J</I> <SUB>c</SUB> values at 4.2 K over the entire applied field regime. The C incorporation occurred even in a low temperature solid-state process of 600 °C, thus resulting in an improvement of the superconducting properties by obtaining both high grain boundary pinning and C substitution effect.</P> <P>[DISPLAY OMISSION]</P>

A Study Using Crystal Transport of Ions in Matter When Boron Ion is Implanted into a Tungsten Trioxide Thin Film

You Kyoung Park,조상완 한국진공학회 2024 Applied Science and Convergence Technology Vol.33 No.3

Recently, numerous thin-film doping methods, such as solar cells, have been employed to improve semiconductor efficiency. Simulations of boron ion (B-ion) implantation using crystal transport of ions in matter obtained the depth profile. To obtain the result of hole concentration using the hole concentration program as the depth profile, a phenomenon caused by B-ions implantation into Si can be expected. The hole concentration also decreased as the dose that penetrated profoundly decreased, owing to the tungsten trioxide thin films (WO3-TF). Therefore, the dose optimized for the thickness of the WO3-TF and the initial ion implantation energy can be predicted using the two programs. In addition, using hole concentration data, it was possible to determine the depth at which the electrical conductivity appeared.

Interface States in Bilayer Graphene Encapsulated by Hexagonal Boron Nitride

Lee, Kayoung,Liu, En-Shao,Watanabe, Kenji,Taniguchi, Takashi,Nah, Junghyo American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.48

<P>The threshold voltages at the onset of conduction for electron and hole branches can provide information on band gap values or interface states in a gap. We measured conductivity of bilayer graphene encapsulated by hexagonal boron nitride as a function of back and top gates, where another bilayer graphene is used as a top gate. From the measured conductivity the transport gap values were extracted assuming zero interface trap states, and they are close to the theoretically expected gap values. From a little discrepancy an average density of interface states per energy within a band gap (<I>D</I><SUB>it</SUB>) is also estimated. The data clearly show that <I>D</I><SUB>it</SUB> decreases as a bilayer graphene band gap increases rather than being constant. Despite the decreasing trend of <I>D</I><SUB>it</SUB>, interestingly the total interface states within a gap increases linearly as a band gap increases. This is because of ∼2 × 10<SUP>10</SUP> cm<SUP>-2</SUP> interface states localized at band edges even without a band gap, and other gap states are equally spread over the gap.</P> [FIG OMISSION]</BR>

Anomalous Ambipolar Transport of Organic Semiconducting Crystals via Control of Molecular Packing Structures

Park, Beomjin,Kim, Kyunghun,Park, Jaesung,Lim, Heeseon,Lanh, Phung Thi,Jang, A-Rang,Hyun, Chohee,Myung, Chang Woo,Park, Seungkyoo,Kim, Jeong Won,Kim, Kwang S.,Shin, Hyeon Suk,Lee, Geunsik,Kim, Se Hyun American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.33

<P>Organic crystals deposited on 2-dimensional (2D) van der Waals substrates have been widely investigated due to their unprecedented crystal structures and electrical properties. van der Waals interaction between organic molecules and the substrate induces epitaxial growth of high quality organic crystals and their anomalous crystal morphologies. Here, we report on unique ambipolar charge transport of a 'lying-down' pentacene crystal grown on a 2D hexagonal boron nitride van der Waals substrate. From in-depth analysis on crystal growth behavior and ultraviolet photoemission spectroscopy measurement, it is revealed that the pentacene crystal at the initial growth stage have a lattice-strained packing structure and unique energy band structure with a deep highest occupied molecular orbital level compared to conventional 'standing-up' crystals. The lattice-strained pentacene few layers enable ambipolar charge transport in field-effect transistors with balanced hole and electron field-effect mobilities. Complementary logic circuits composed of the two identical transistors show clear inverting functionality with a high gain up to 15. The interesting crystal morphology of organic crystals on van der Waals substrates is expected to attract broad attentions on organic/2D interfaces for their electronic applications.</P>

The coat protein of Alternanthera mosaic virus is the elicitor of a temperature-sensitive systemic necrosis in Nicotiana benthamiana, and interacts with a host boron transporter protein

Lim, H.S.,Nam, J.,Seo, E.Y.,Nam, M.,Vaira, A.M.,Bae, H.,Jang, C.Y.,Lee, C.H.,Kim, H.G.,Roh, M.,Hammond, J. Academic Press 2014 Virology Vol.452 No.-

Different isolates of Alternanthera mosaic virus (AltMV; Potexvirus), including four infectious clones derived from AltMV-SP, induce distinct systemic symptoms in Nicotiana benthamiana. Virus accumulation was enhanced at 15<SUP>o</SUP>C compared to 25<SUP>o</SUP>C; severe clone AltMV 3-7 induced systemic necrosis (SN) and plant death at 15<SUP>o</SUP>C. No interaction with potexvirus resistance gene Rx was detected, although SN was ablated by silencing of SGT1, as for other cases of potexvirus-induced necrosis. Substitution of AltMV 3-7 coat protein (CP<SUB>SP</SUB>) with that from AltMV-Po (CP<SUB>Po</SUB>) eliminated SN at 15<SUP>o</SUP>C, and ameliorated symptoms in Alternanthera dentata and soybean. Substitution of only two residues from CP<SUB>Po</SUB> [either MN(13,14)ID or LA(76,77)IS] efficiently ablated SN in N. benthamiana. CP<SUB>SP</SUB> but not CP<SUB>Po</SUB> interacted with Arabidopsis boron transporter protein AtBOR1 by yeast two-hybrid assay; N. benthamiana homolog NbBOR1 interacted more strongly with CP<SUB>SP</SUB> than CP<SUB>Po</SUB> in bimolecular fluorescence complementation, and may affect recognition of CP as an elicitor of SN.