Showing papers by "Hyun-Chul Kim published in 2021"

Cation-disordered rocksalt-type high-entropy cathodes for Li-ion batteries

Abstract: High-entropy (HE) ceramics, by analogy with HE metallic alloys, are an emerging class of solid solutions composed of a large number of species. These materials offer the benefit of large compositional flexibility and can be used in a wide variety of applications, including thermoelectrics, catalysts, superionic conductors and battery electrodes. We show here that the HE concept can lead to very substantial improvements in performance in battery cathodes. Among lithium-ion cathodes, cation-disordered rocksalt (DRX)-type materials are an ideal platform within which to design HE materials because of their demonstrated chemical flexibility. By comparing a group of DRX cathodes containing two, four or six transition metal (TM) species, we show that short-range order systematically decreases, whereas energy density and rate capability systematically increase, as more TM cation species are mixed together, despite the total metal content remaining fixed. A DRX cathode with six TM species achieves 307 mAh g−1 (955 Wh kg−1) at a low rate (20 mA g−1), and retains more than 170 mAh g−1 when cycling at a high rate of 2,000 mA g−1. To facilitate further design in this HE DRX space, we also present a compatibility analysis of 23 different TM ions, and successfully synthesize a phase-pure HE DRX compound containing 12 TM species as a proof of concept. High-entropy ceramics are solid solutions offering compositional flexibility and wide variety of applicability. High-entropy concepts are shown to lead to substantial performance improvement in cation-disordered rocksalt-type cathodes for Li-ion batteries.

Search for supersymmetry in final states with two oppositely charged same-flavor leptons and missing transverse momentum in proton-proton collisions at √s = 13 TeV

Abstract: A search for phenomena beyond the standard model in final states with two oppositely charged same-flavor leptons and missing transverse momentum is presented. The search uses a data sample of proton-proton collisions at $ \sqrt{s} $ = 13 TeV, corresponding to an integrated luminosity of 137 fb$^{−1}$, collected by the CMS experiment at the LHC. Three potential signatures of physics beyond the standard model are explored: an excess of events with a lepton pair, whose invariant mass is consistent with the Z boson mass; a kinematic edge in the invariant mass distribution of the lepton pair; and the nonresonant production of two leptons. The observed event yields are consistent with those expected from standard model backgrounds. The results of the first search allow the exclusion of gluino masses up to 1870 GeV, as well as chargino (neutralino) masses up to 750 (800) GeV, while those of the searches for the other two signatures allow the exclusion of light-flavor (bottom) squark masses up to 1800 (1600) GeV and slepton masses up to 700 GeV, respectively, at 95% confidence level within certain supersymmetry scenarios.[graphic not available: see fulltext]

Realizing continuous cation order-to-disorder tuning in a class of high-energy spinel-type Li-ion cathodes

Abstract: Summary Conventional Li-ion cathode materials are dominated by well-ordered structures, in which Li and transition metals occupy distinct crystallographic sites. We show in this paper that profoundly new degrees of freedom for the optimization of electrochemical properties may be accessed if controllable cation disorder is introduced. In a class of high-capacity spinel-type cathode materials, we identify cation to anion ratio in synthesis as a key parameter for tuning the structure continuously from a well-ordered spinel, through a partially ordered spinel, to rocksalt. We find that the varying degree of cation disorder modifies the voltage profile, rate capability, and charge-compensation mechanism in a rational and predictable way. Our results indicate that spinel-type order is most beneficial for achieving high-rate performance as long as the cooperative 8a to 16c phase transition is suppressed, while more rocksalt-like disorder facilitates O redox, which can increase capacity. Our findings reveal an important tuning handle for achieving high energy and power in the vast space of partially ordered cathode materials.

Search for dark matter produced in association with a leptonically decaying Z boson in proton-proton collisions at $\sqrt{s} =$ 13 TeV

Abstract: A search for dark matter particles is performed using events with a Z boson candidate and large missing transverse momentum. The analysis is based on proton–proton collision data at a center-of-mass energy of 13$\,\text {Te}\text {V}$, collected by the CMS experiment at the LHC in 2016–2018, corresponding to an integrated luminosity of 137$\,\text {fb}^{-1}$. The search uses the decay channels ${\mathrm{Z}} \rightarrow {\mathrm{e}} {\mathrm{e}} $ and ${\mathrm{Z}} \rightarrow {{\upmu }{}{}} {{\upmu }{}{}} $. No significant excess of events is observed over the background expected from the standard model. Limits are set on dark matter particle production in the context of simplified models with vector, axial-vector, scalar, and pseudoscalar mediators, as well as on a two-Higgs-doublet model with an additional pseudoscalar mediator. In addition, limits are provided for spin-dependent and spin-independent scattering cross sections and are compared to those from direct-detection experiments. The results are also interpreted in the context of models of invisible Higgs boson decays, unparticles, and large extra dimensions.

Search for new physics in top quark production with additional leptons in proton-proton collisions at $\sqrt{s} = $ 13 TeV using effective field theory

Abstract: Events containing one or more top quarks produced with additional prompt leptons are used to search for new physics within the framework of an effective field theory (EFT). The data correspond to an integrated luminosity of 41.5 fb$^{−1}$ of proton-proton collisions at a center-of-mass energy of 13 TeV at the LHC, collected by the CMS experiment in 2017. The selected events are required to have either two leptons with the same charge or more than two leptons; jets, including identified bottom quark jets, are also required, and the selected events are divided into categories based on the multiplicities of these objects. Sixteen dimension-six operators that can affect processes involving top quarks produced with additional charged leptons are considered in this analysis. Constructed to target EFT effects directly, the analysis applies a novel approach in which the observed yields are parameterized in terms of the Wilson coefficients (WCs) of the EFT operators. A simultaneous fit of the 16 WCs to the data is performed and two standard deviation confidence intervals for the WCs are extracted; the standard model expectations for the WC values are within these intervals for all of the WCs probed.[graphic not available: see fulltext]

Strong force fields and stabilities of the nucleon and singly heavy baryon Σ c

Abstract: We investigate the strong force fields and stabilities of the nucleon and the singly heavy baryon ${\mathrm{\ensuremath{\Sigma}}}_{c}$ within the framework of the chiral quark-soliton model. Having constructed the pion mean fields in the presence of the ${N}_{c}\ensuremath{-}1$ level quarks self-consistently, we are able to examine the gravitational form factors of ${\mathrm{\ensuremath{\Sigma}}}_{c}$. We mainly focus in the present work on the stability conditions for both the nucleon and ${\mathrm{\ensuremath{\Sigma}}}_{c}$ and discuss the strong force fields and their physical implications. We also present the results for the gravitational form factors and relevant observables, emphasizing the difference between the nucleon and ${\mathrm{\ensuremath{\Sigma}}}_{c}$.

OGUs enable effective, phylogeny-aware analysis of even shallow metagenome community structures

Abstract: We introduce Operational Genomic Unit (OGU), a metagenome analysis strategy that directly exploits sequence alignment hits to individual reference genomes as the minimum unit for assessing the diversity of microbial communities and their relevance to environmental factors This approach is independent from taxonomic classification, granting the possibility of maximal resolution of community composition, and organizes features into an accurate hierarchy using a phylogenomic tree The outputs are suitable for contemporary analytical protocols for community ecology, differential abundance and supervised learning while supporting phylogenetic methods, such as UniFrac and phylofactorization, that are seldomly applied to shotgun metagenomics despite being prevalent in 16S rRNA gene amplicon studies As demonstrated in one synthetic and two real-world case studies, the OGU method produces biologically meaningful patterns from microbiome datasets Such patterns further remain detectable at very low metagenomic sequencing depths Compared with taxonomic unit-based analyses implemented in currently adopted metagenomics tools, and the analysis of 16S rRNA gene amplicon sequence variants, this method shows superiority in informing biologically relevant insights, including stronger correlation with body environment and host sex on the Human Microbiome Project dataset, and more accurate prediction of human age by the gut microbiomes in the Finnish population We provide Woltka, a bioinformatics tool to implement this method, with full integration with the QIIME 2 package and the Qiita web platform, to facilitate OGU adoption in future metagenomics studies Importance Shotgun metagenomics is a powerful, yet computationally challenging, technique compared to 16S rRNA gene amplicon sequencing for decoding the composition and structure of microbial communities However, current analyses of metagenomic data are primarily based on taxonomic classification, which is limited in feature resolution compared to 16S rRNA amplicon sequence variant analysis To solve these challenges, we introduce Operational Genomic Units (OGUs), which are the individual reference genomes derived from sequence alignment results, without further assigning them taxonomy The OGU method advances current read-based metagenomics in two dimensions: (i) providing maximal resolution of community composition while (ii) permitting use of phylogeny-aware tools Our analysis of real-world datasets shows several advantages over currently adopted metagenomic analysis methods and the finest-grained 16S rRNA analysis methods in predicting biological traits We thus propose the adoption of OGU as standard practice in metagenomic studies

Difficult Biliary Cannulation from the Perspective of Post-Endoscopic Retrograde Cholangiopancreatography Pancreatitis: Identifying the Optimal Timing for the Rescue Cannulation Technique.

Abstract: Background/aims Recently, the European Society of Gastrointestinal Endoscopy (ESGE) proposed criteria for "difficult biliary cannulation" during endoscopic retrograde cholangiopancreatography (ERCP). This study aimed to investigate the clinical relevance of the ESGE criteria from the perspective of post-ERCP pancreatitis (PEP). Methods An ERCP database was prospectively maintained between November 2014 and December 2015 across six teaching hospitals in South Korea. The ESGE criteria (biliary cannulation time, the number of cannulation attempts, and inadvertent pancreatic duct [PD] manipulation) were recorded in this database as well as other technical factors. Logistic regression analysis was used to identify risk factors for PEP. Then, the PEP prediction model was investigated using decision tree analysis. Results We analyzed 1,067 consecutive patients with naive papilla. The overall rate of PEP was 6.6%. Multivariate analysis revealed that female sex (odds ratio [OR], 1.860; 95% confidence interval [CI], 1.124 to 3.078), a selective biliary cannulation duration >5 minutes (OR, 3.282; 95% CI, 1.641 to 6.566), and inadvertent PD manipulation (OR, 2.614; 95% CI, 1.480 to 4.617) were significant factors affecting PEP. Decision tree analysis revealed that biliary cannulation time (χ2=49.857, p 5 minutes, and >5 minutes with inadvertent PD manipulation, respectively. Conclusions Biliary cannulation time and inadvertent PD manipulation could be relevant indicators of PEP, and 5 minutes might be used as a cutoff value for the implementation of the rescue cannulation technique.

The very forward CASTOR calorimeter of the CMS experiment

Abstract: The physics motivation, detector design, triggers, calibration, alignment, simulation, and overall performance of the very forward CASTOR calorimeter of the CMS experiment are reviewed. The CASTOR Cherenkov sampling calorimeter is located very close to the LHC beam line, at a radial distance of about 1 cm from the beam pipe, and at 14.4 m from the CMS interaction point, covering the pseudorapidity range of $-$6.6 $\lt\eta\lt$ $-$5.2. It was designed to withstand high ambient radiation and strong magnetic fields. The performance of the detector in measurements of forward energy density, jets, and processes characterized by rapidity gaps, is reviewed using data collected in proton and nuclear collisions at the LHC.

Patients with epiglottic collapse showed less severe obstructive sleep apnea and good response to treatment other than continuous positive airway pressure: a case-control study of 224 patients.

Abstract: Study Objectives:The purpose of this study was to analyze patients with epiglottic collapse, especially their clinical characteristics related to obstructive sleep apnea and phenotype labeling usin...

Measurement of differential $\mathrm{t\bar{t}}$ production cross sections using top quarks at large transverse momenta in $pp$ collisions at $\sqrt{s} =$ 13 TeV

Abstract: A measurement is reported of differential top quark pair (tt¯) production cross sections, where top quarks are produced at large transverse momenta The data collected with the CMS detector at the LHC are from pp collisions at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 359 fb-1 The measurement uses events where at least one top quark decays as t→Wb→qq¯′b and is reconstructed as a large-radius jet with transverse momentum in excess of 400 GeV The second top quark is required to decay either in a similar way or leptonically, as inferred from a reconstructed electron or muon, a bottom quark jet, and missing transverse momentum due to the undetected neutrino The cross section is extracted as a function of kinematic variables of individual top quarks or of the tt¯ system The results are presented at the particle level, within a region of phase space close to that of the experimental acceptance, and at the parton level and are compared to various theoretical models In both decay channels, the observed absolute cross sections are significantly lower than the predictions from theory, while the normalized differential measurements are well described

Continuous 3D-nanopatterned Ni–Mo solid solution as a free-standing electrocatalyst for the hydrogen evolution reaction in alkaline medium

Abstract: To date, researchers have shown that nanostructured solid solutions of transition metal electrocatalysts can improve hydrogen evolution reaction (HER) activity in alkaline media. However, there are few reports that focus on mass producing efficient electrocatalysts for the HER based on continuous 3-dimensional (3D) nanopatterning. Herein, a 3D-nanopatterned solid solution of Ni–Mo is synthesized to provide efficient electrocatalytic activity in alkaline electrolytes. Experimentally, it is found that the electrochemically active surface area (ECSA) is 65 times higher than that of 2D Ni–Mo. Additionally, the charge transfer resistance (Rct) of 3D Ni–Mo (0.6 Ω) is 16 times lower than that of 2D Ni–Mo (10.3 Ω), which shows that 3D Ni–Mo allows the fast transport of ions and facilitates the H* desorption process; thus, the above result contributes to the improved kinetics for HER activity. Moreover, the 3D-nanopatterned Ni–Mo electrocatalyst requires a minimum overpotential of 39 mV to achieve a 10 mA cm−2 current density, which is very close to that of the benchmark Pt/C electrocatalyst (30 mV) for the HER in alkaline media. In addition, the 3D-nanopatterned Ni–Mo electrocatalyst exhibits 94.7% faradaic efficiency during the HER. The as-prepared 3D-nanopatterned Ni–Mo is a free-standing electrocatalyst that can be synthesized at the inch scale or even larger and will be useful for practical applications in future renewable energy devices.

Validity and Reliability for the Use of Program Outcome Indirect Measurement Tool in Korean Nursing Baccalaureate Education

Abstract: The aim of this study was to verify the feasibility and reliability of the program outcome indirect measurement tool developed for nursing college students in Korean. 396 nursing students from 5 nursing colleges participated in this study, data were collected from November 22 to December 10, 2019. Data analysis was conducted using the IBM Statistics SPSS 21.0 and AMOS 21.0 programs to analyze item analysis, exploratory and confirmatory factor analysis. As a result of the item analysis, all 79 items were selected for factor analysis. In the exploratory factor analysis, five items that were loaded with other factors were deleted. The final factor loading range was from .37 to .86, and the cumulative explanatory variance for 12 factors was 71.71%. No items were deleted as a result of the confirmatory factor analysis, and the final scale was consisted of 74 items. The average score for scale was 3.78 and Cronbach'⍺ was .98. The feasibility and reliability of the program outcome indirect measurement tool have been verified through this study. Therefore it can be used as a more standardized indirect measurement tool for nursing college students. ■ keyword :∣Nursing Education∣Program Outcome∣Evaluation System∣Indirect Measurement∣Validity∣ * 본 연구는 2019년도 남부대학교 학술연구비의 지원으로 수행되었습니다. 접수일자 : 2021년 04월 23일 수정일자 : 2021년 05월 27일 심사완료일 : 2021년 06월 14일 교신저자 : 김희영, e-mail : kimhy@dsu.ac.kr 간호교육 프로그램 학습성과 간접측정도구의 활용을 위한 신뢰도 및 타당도 검증 609

Computational and experimental search for potential polyanionic K-ion cathode materials

Abstract: Discovering high-energy cathode materials is critical to construct K-ion batteries for practical applications. Owing to the great success of layered oxides in Li- and Na-ion systems, K layered cathodes have also been investigated in recent years. However, the much larger size of K+ compared to Li or Na introduces strong K+–K+ interaction within the layer, which results in a sloped voltage profile thereby limiting the specific capacity and operating voltage. In contrast, polyanionic materials with a three-dimensional K+ arrangement can effectively mitigate K+–K+ interaction. In this work, ten K polyanionic compounds with theoretical capacity >100 mA h g−1 are screened from the Inorganic Crystal Structure Database as potential cathode materials for K-ion batteries. Among the ten proposed compounds, K2MnP2O7, K2Mn2P2O7F2, K2Fe2P2O7F2, and K6V2(PO4)4 with average voltage <4.5 V are synthesized and evaluated electrochemically. While the re-insertion of K into these compounds is not fully reversible, it may be related to the very high migration barrier that we compute for K ions. In addition, we show the successful synthesis of a series of K3V3−xCrx(PO4)4 (x = 0, 1, 2, 3) compounds. Among these, K3V2Cr(PO4)4 exhibits the largest reversible capacity, as revealed by the in situ investigation. Finally, we find that the redox couples in many of these compounds sit at remarkably high potential, even higher than in equivalent Li compounds, which brings both opportunities and challenges in the future research of K polyanion cathodes.

Three-Dimensional Porous Frameworks for Li Metal Batteries: Superconformal versus Conformal Li Growth.

Abstract: Li metal batteries have been considered a promising alternative to Li-ion batteries because of the high theoretical capacity of the Li metal. There have been remarkable improvements in the electrochemical performance of Li metal electrodes, although the current Li metal technology is not sufficiently practical in terms of cycle performance, safety, and volume change during cycling. Herein, the role of pore size distribution in the Li metal plating behavior of porous frameworks is clarified to attain the ideal pore structure of the framework as a Li metal host. The monodisperse pore framework shows the conformal electrodeposition of the Li metal, whereas the pore size gradient framework exhibits the superconformal plating of the Li metal. The conformal and superconformal electrodepositions of the Li metal are elucidated in terms of variations along the pore depth direction in the charge-transfer resistance on the pore walls and the ionic resistance of electrolytes confined in pores. The pore size gradient framework also shows excellent electrochemical performance, such as stable capacity retention over 760 cycles with 0.5 mAh cm-2 at 2 mA cm-2. These findings provide fundamental insights into strategies to improve the electrochemical performance of porous frameworks for Li metal batteries.

Mechanically sensing and tailoring electronic properties in two-dimensional atomic membranes

Abstract: Two-dimensional (2D) van der Waals materials are both highly deformable atomic membranes and electrically active quantum materials. Most electronic and quantum states in both monolayer 2D materials and heterostructures are highly sensitive to strain and interlayer structure, and thus may be tuned mechanically. Here we explore the current frontiers using 2D material mechanics to sense, tune, tailor or even reconfigure electronic properties, device behavior and quantum states. We compare the relative impacts of different kinds of mechanical perturbations including in-plane strain, out-of-plane vibrations, inhomogeneous three-dimensional deformations, instabilities of membranes under compression like crumpling and wrinkling, and interlayer slip. Throughout, we explore how each form of coupling may be used for applications that cannot be realized in the flat unperturbed materials including tunable nanoelectromechanical systems, strain resilient electronics, multifunctional surfaces and reconfigurable quantum systems.

Transcranial focused ultrasound modulates cortical and thalamic motor activity in awake sheep.

Abstract: Transcranial application of pulsed low-intensity focused ultrasound (FUS) modulates the excitability of region-specific brain areas, and anesthetic confounders on brain activity warrant the evaluation of the technique in awake animals. We examined the neuromodulatory effects of FUS in unanesthetized sheep by developing a custom-fit headgear capable of reproducibly placing an acoustic focus on the unilateral motor cortex (M1) and corresponding thalamic area. The efferent responses to sonication, based on the acoustic parameters previously identified in anesthetized sheep, were measured using electromyography (EMG) from both hind limbs across three experimental conditions: on-target sonication, off-target sonication, and without sonication. Excitatory sonication yielded greater amplitude of EMG signals obtained from the hind limb contralateral to sonication than that from the ipsilateral limb. Spurious appearance of motion-related EMG signals limited the amount of analyzed data (~ 10% selection of acquired data) during excitatory sonication, and the averaged EMG response rates elicited by the M1 and thalamic stimulations were 7.5 ± 1.4% and 6.7 ± 1.5%, respectively. Suppressive sonication, while sheep walked on the treadmill, temporarily reduced the EMG amplitude from the limb contralateral to sonication. No significant change was found in the EMG amplitudes during the off-target sonication. Behavioral observation throughout the study and histological analysis showed no sign of brain tissue damage caused by the acoustic stimulation. Marginal response rates observed during excitatory sonication call for technical refinement to reduce motion artifacts during EMG acquisitions as well as acoustic aberration correction schemes to improve spatial accuracy of sonication. Yet, our results indicate that low-intensity FUS modulated the excitability of regional brain tissues reversibly and safely in awake sheep, supporting its potential in theragnostic applications.

Korean red ginseng suppresses 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced inflammation in the substantia nigra and colon

Abstract: Parkinson’s disease (PD) is a neurodegenerative disease involving dopaminergic neuronal death in the substantia nigra (SN); recent studies have shown that interactions between gut and brain play a critical role in the pathogenesis of PD. In this study, the anti-inflammatory effect of Korean red ginseng (KRG) and the changes in gut microbiota were evaluated in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model. Male nine-week-old C57BL/6 mice were injected intraperitoneally with 30 mg/kg of MPTP at 24-h intervals for 5 days. Two hours after the daily MPTP injection, the mice were orally administered 100 mg/kg of KRG, which continued for 7 days beyond the MPTP injections, for a total of 12 consecutive days. Eight days after the final KRG administration, the pole and rotarod tests were performed and brain and colon samples of the mice were collected. Dopaminergic neuronal death, activation of microglia and astrocytes, α-synuclein and expressions of inflammatory cytokines and disruption of tight junction were evaluated. In addition, 16S ribosomal RNA gene sequencing of mouse fecal samples was performed to investigate microbiome changes. KRG treatment prevented MPTP-induced behavioral impairment, dopaminergic neuronal death, activation of microglia and astrocytes in the nigrostriatal pathway, disruption of tight junction and the increase in α-synuclein, interleukin-1β and tumor necrosis factor-α expression in the colon. The 16S rRNA sequencing revealed that MPTP altered the number of bacterial species and their relative abundances, which were partially suppressed by KRG treatment. Especially, KRG suppressed the abundance of the inflammation-related phylum Verrucomicrobia and genera Ruminococcus and Akkermansia (especially Akkermansia muciniphila), and elevated the abundance of Eubacterium, which produces the anti-inflammatory substances. These findings suggest that KRG prevents MPTP-induced dopaminergic neuronal death, activation of microglia and astrocytes, and accumulation of α-synuclein in the SN, and the regulation of inflammation-related factors in the colon may influence the effect.

Clinical outcomes and predictors of response for adalimumab in patients with moderately to severely active ulcerative colitis: a KASID prospective multicenter cohort study.

Abstract: Background/Aims This study assessed the efficacy and safety of adalimumab (ADA) and explored predictors of response in Korean patients with ulcerative colitis (UC). Methods A prospective, observational, multicenter study was conducted over 56 weeks in adult patients with moderately to severely active UC who received ADA. Clinical response, remission, and mucosal healing were assessed using the Mayo score. Results A total of 146 patients were enrolled from 17 academic hospitals. Clinical response rates were 52.1% and 37.7% and clinical remission rates were 24.0% and 22.0% at weeks 8 and 56, respectively. Mucosal healing rates were 39.0% and 30.1% at weeks 8 and 56, respectively. Prior use of anti-tumor necrosis factor-α (anti-TNF-α) did not affect clinical and endoscopic responses. The ADA drug level was significantly higher in patients with better outcomes at week 8 (P<0.05). In patients with lower endoscopic activity, higher body mass index, and higher serum albumin levels at baseline, the clinical response rate was higher at week 8. In patients with lower Mayo scores and C-reactive protein levels, clinical responses, and mucosal healing at week 8, the clinical response rate was higher at week 56. Serious adverse drug reactions were identified in 2.8% of patients. Conclusions ADA is effective and safe for induction and maintenance in Korean patients with UC, regardless of prior anti-TNF-α therapy. The ADA drug level is associated with the efficacy of induction therapy. Patients with better short-term outcomes were predictive of those with an improved long-term response.

Janus behaviour of LiFSI- and LiPF6-based electrolytes for Li metal batteries: chemical corrosion versus galvanic corrosion

Abstract: Li metal has been considered a promising anode for high energy density Li batteries because of the lowest redox potential and high specific capacity of the Li/Li+ redox couple. However, Li metal technology is currently impractical because of its poor calendar aging behaviour due to chemical and galvanic corrosion, although recent efforts have shown promise in improving the cycle performance of Li metal. Calendar aging of Li metal is one of the challenges that must be overcome to translate research into practical applications. Nevertheless, even the calendar aging mechanism of Li metal is not yet fully understood. Herein, the Janus behaviour of LiPF6- and LiFSI-based electrolytes in the electrochemical performance of Li metal is demonstrated in terms of chemical corrosion and galvanic corrosion. LiFSI is superior to LiPF6 in chemical corrosion, whereas LiFSI is inferior to LiPF6 in galvanic corrosion. This is attributed to the fact that LiPF6- and LiFSI-based electrolytes show remarkably different behaviour of electrolyte decomposition on the Li metal and Cu substrate surfaces. Moreover, the ensemble effect of LiFSI salt and VC additive is introduced to simultaneously suppress galvanic corrosion and chemical corrosion, leading to not only excellent cycle performance but also improved calendar aging.

Electric quadrupole form factors of singly heavy baryons with spin 3/2

Abstract: We study the electromagnetic form factors of the lowest-lying singly heavy baryons in a pion mean-field approach, which is also known as the SU(3) chiral quark-soliton model. In the limit of the heavy-quark mass, the dynamics inside a singly heavy baryon is governed by the $N_c-1$ valence quarks, while the heavy quark remains as a mere static color source. In this framework, a singly heavy baryon is described by combining the colored soliton with the singly heavy quark. In the infinitely heavy-quark mass limit, we can compute the electric quadrupole form factors of the baryon sextet with spin 3/2 with the rotational $1/N_c$ and linear corrections of the explicit flavor SU(3) symmetry breaking taken into account. We find that the sea-quark contributions or the Dirac-sea level contributions dominate over the valence-quark contributions in lower $Q^2$ region. We examined the effects of explicit flavor SU(3) symmetry breaking in detail. The numerical results are also compared with the recent data from the lattice calculation with the unphysical value of the pion mass considered, which was used in the lattice calculation.

A Systematic Review of Location Aware Schemes in the Internet of Things.

Abstract: The rapid development in wireless technologies is positioning the Internet of Things (IoT) as an essential part of our daily lives. Localization is one of the most attractive applications related to IoT. In the past few years, localization has been gaining attention because of its applicability in safety, health monitoring, environment monitoring, and security. As a result, various localization-based wireless frameworks are being presented to improve such applications’ performances based on specific key performance indicators (KPIs). Therefore, this paper explores the recently proposed localization schemes in IoT. Initially, this paper explains the major KPIs of localization. After that, a thorough comparison of recently proposed localization schemes based on the KPIs is presented. The comparison includes an overview, architecture, network structure, performance parameters, and target KPIs. At the end, possible future directions are presented for the researchers working in this domain.

7.9 1/2.74-inch 32Mpixel-Prototype CMOS Image Sensor with 0.64 μ m Unit Pixels Separated by Full-Depth Deep-Trench Isolation

Abstract: For years, there has been a strong drive for sub-micron pixel development, in spite of reaching the visible light diffraction limit, because a smaller pixel pitch of CMOS image sensors (CISs) is inevitably required for ever-miniaturizing camera modules as mobile devices incorporate more cameras, few of which are dedicated to ultra-high-resolution zoomed images [1]. To that end, image sensor vendors have tried to find new ways to avoid reduction in sensitivity and more crosstalk in the sensor through pixel architecture change and/or fabrication process refinement [2] –[4]. For example, a $0.7 \mu m$ pixel sensor was demonstrated with acceptable photodiode (PD) full-well capacity (FWC) of $\gt 6$,000e- as well as signal-to-noise ratio (SNR) of $\sim32$ dB without optical/electrical crosstalk by employing state-of-the-art full-depth deep-trench isolations (FDTIs). [4] However, further scaling requires elaborate fabrication innovation and layout ideas. At the same time, meeting every aspect of pixel performance compared to the previous generation becomes even more difficult, e.g., with respect to dark or illuminated characteristics, fixed-pattern or temporal noises, etc. The latter, in particular, is associated with in-pixel source-follower (SF) amplifiers. Therefore, electrical performance of scaled in-pixel transistors cannot be overlooked. In this paper, a 32-megpixel (MP) CIS with $0.64 \mu m$ unit pixels is demonstrated with FDTI design. Innovations in terms of fabrication and design to achieve this performance with scaling are discussed.

Effects of Depression, Sleep and Self-Esteem on Dementia Preventive Behavior in Rural Elderly People

Abstract: The purpose of this study was to examine the effects of depression, sleep, and self-esteem on a dementia preventive behavior in rural elderly people. The participants were 235 elderly people aged 60 or older who lived in J-Gun, J-Do. Data were collected using structured questionnaires and analyzed using t-test, one-way ANOVA, Scheffe test, Pearson correlation coefficients, and stepwise multiple regression with SPSS/WIN 25.0 program. There were significant differences in the dementia preventive behavior according to religion, the level of education, a cohabitation type, an economic level, and dementia education experience. Participants' dementia preventive behavior was positively correlated with self-esteem (r=.52, p<.001) and sleep (r=.31, p<.001). However, it was negatively correlated with depression (r=-.57, p<.001). Factors affecting the dementia preventive behavior were depression, self-esteem, and religion. The explanatory power of variables was 37%. To increase a dementia prevention behavior in rural elderly people, it is necessary to develop dementia prevention programs to reduce depression and improve self-esteem and to create social conditions to facilitate various social participations such as a religious activity. ■ keyword :∣Depression∣Sleep∣Self-Esteem∣Dementia∣Behavior∣ 접수일자 : 2021년 01월 29일 수정일자 : 2021년 03월 16일 심사완료일 : 2021년 04월 08일 교신저자 : 김희영, e-mail : hykim@dsu.ac.kr 농촌노인의 우울, 수면, 자아존중감이 치매예방행위에 미치는 영향 971

Energy-momentum tensor of the nucleon on the light front: Abel tomography case

Abstract: We investigate the two-dimensional energy-momentum-tensor (EMT) distributions of the nucleon on the light front, using the Abel transforms of the three-dimensional EMT ones. We explicitly show that the main features of all EMT distributions are kept intact in the course of the Abel transform. We also examine the equivalence between the global and local conditions for the nucleon stability in the three-dimensional Breit frame and in the two-dimensional transverse plane on the light front. We also discuss the two-dimensional force fields inside a nucleon on the light front.