http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Ahn, Sungjun,Lee, Jae-young,Lim, Bo-Mi,Kwon, Hae-Chan,Hur, Namho,Park, Sung-Ik Electronics and Telecommunications Research Instit 2021 ETRI Journal Vol.43 No.3
This paper theoretically and empirically explores the reliability gain that can be obtained by installing multiple antennas in on-vehicle broadcasting receivers. Analytical derivations reveal that maximal-ratio-combining-based diversity allows a multi-antenna receiver (MR) to achieve significantly better coverage probability than a single-antenna receiver (SR). In particular, the notable MR gains for low-power reception and high-throughput services are highlighted. We also discuss various aspects of mobile MRs, including geometric coverage, volume of the users served, and impact of receiver velocity. To examine the feasibility of MRs in the real world, extensive field experiments were conducted, particularly with on-air ATSC 3.0 broadcast transmissions. Relying on the celebrated erroneous second ratio criterion, MRs with two and four antennas were verified to achieve notable reliability gains over SRs in practice. Furthermore, our results also prove that layered-division multiplexing can cope better with receiver mobility than traditional time-division multiplexing when multiple services are intended in the same radio frequency channel.
Impact of Intolerance of Uncertainty on Brain Structural Changes in Panic Disorder
Sungjun Ahn,Sang-Hyuk Lee,Kang Soo Lee 대한신경정신의학회 2023 PSYCHIATRY INVESTIGATION Vol.20 No.11
Objective This study investigated the impact of intolerance of uncertainty (IU) on structural changes in the brain and symptom severity in patients with panic disorder.Methods This study included 90 participants diagnosed with panic disorder. The IU Scale, Panic Disorder Severity Scale (PDSS), Beck Depression Inventory-II (BDI-II), Penn State Worry Questionnaire (PSWQ), Self-Forgiveness Scale (SFS), and Short Form 36 Health Survey (SF) were used. A voxel-wise correlation analysis was conducted to investigate the structural differences in the gray matter.Results As IU increased, the cortical thickness of the right lingual gyrus decreased significantly, while the gray matter volume of the right pars triangularis increased. The cortical thickness of the right lingual gyrus showed a significant negative correlation with the BDI-II score and a positive correlation with the SFS. Additionally, the gray matter volume of the right pars triangularis was positively correlated with the PDSS, PSWQ, and BDI-II scores and negatively correlated with the mental health domain of the SF.Conclusion According to our findings, elevated IU in participants with panic disorder was associated with cortical thinning in the lingual gyrus and increased gray matter volume in the pars triangularis. These structural alterations may also have an impact on perceived quality of life, as well as high levels of depression and anxiety.
Ahn, Chi-Yeong,Hwang, Wonchan,Lee, Hyunjoon,Kim, Sungjun,Park, Ji Eun,Kim, Ok-Hee,Her, Min,Cho, Yong-Hun,Sung, Yung-Eun Elsevier 2018 International journal of hydrogen energy Vol.43 No.21
<P><B>Abstract</B></P> <P>An ideal oxygen reduction catalyst for use in fuel cells should exhibit both long-term durability and high activity. In this study, to increase the durability of highly loaded platinum- and platinum-nickel alloy catalysts possessing different types of carbon supports, a nitrogen-doped carbon shell was introduced on the catalyst surface through dopamine coating. As the catalyst surfaces were altered following shell formation, the ionomer contents of the catalyst inks were adjusted to optimise the three-phase boundary formation. Single cell tests were then conducted on these inks by applying them in a membrane electrolyte assembly. Furthermore, to confirm the durability of the catalysts under accelerated conditions, the operation was continued for 200 h at 70 °C and at a relative humidity of 100%. Transmission electron microscopy and electrochemical analysis were conducted before and after the durability tests, and the observed phenomena were discussed for catalysts bearing different types of carbon supports.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Nitrogen-doped carbon shell by dopamine coating is introduced to highly-loaded Pt and PtNi alloy catalysts. </LI> <LI> Pt and PtNi catalysts are supported on carbon black and heat-treated carbon, respectively. </LI> <LI> Performance and durability were improved by applying a Pt-alloy catalyst in combination with a N-doped carbon shell. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Enhanced carbon tolerance on Ni-based reforming catalyst with Ir alloying: A DFT study
Ahn, Kiyong,Choi, Sungjun,Lee, Jong-Ho,Kim, Byung-Kook,Kim, Jedo,Kim, Hyoungchul Elsevier 2017 APPLIED SURFACE SCIENCE - Vol.419 No.-
<P><B>Abstract</B></P> <P>Carbon deposition is a major cause of performance degradation for the Ni-based catalyst used in steam reforming of hydrocarbons. In this work, we perform first principle calculations to show that carbon tolerance behavior can be significantly enhanced by alloying Ni with Ir. The most stable atomic structure predicted by the surface phased diagram shows that Ir atoms prefer to stay on the surface of the alloy ensuring their exposure to the incoming gas. We find that the presence of Ir atoms suppress the surface migration of carbon atoms and weaken the stability of the adsorbed carbon agglomerates. Finally, we elucidate that the local reactivity change caused by the shift in the <I>d</I>-band structure is responsible for such good carbon tolerance behavior.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel Ir-Ni alloy is designed to be used as a catalyst in the reforming process of hydrocarbons. </LI> <LI> The activation energy of a CC bond increases leading to carbon cluster growth suppression. </LI> <LI> Easy removal of adsorbed carbon cluster is predicted for the Ir-Ni alloy. </LI> <LI> Changes in the <I>d</I>-band structure are identified as the source of good carbon tolerance of the Ir-Ni alloy. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>