80 results on '"Ji, Un"'
Search Results
2. Anticipating quantum stochastic integrals.
- Author
-
Ji, Un Cig
- Subjects
- *
STOCHASTIC integrals , *WHITE noise theory , *QUANTUM noise , *WHITE noise , *LINEAR operators , *TOEPLITZ operators - Abstract
Based on the quantum white noise theory, we formulate new types of anticipating quantum stochastic integrals by combining the Hitsuda–Skorokhod quantum stochastic integrals and the interactions between the integrands and the integrators. For our purpose, we prove various versions of analytic characterization theorems of symbols of white noise operators as more general cases. Also, several types of quantum (stochastic) gradients are formulated as continuous linear operators which are related to the quantum white noise derivatives and reflecting the interactions with the external noises. Finally, we formulate further systematical study of anticipating quantum stochastic integrals. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Enhanced Electrical and Thermal Conductivities of Polymer Composites with a Segregated Network of Graphene Nanoplatelets.
- Author
-
Kim, Ki Hoon, Jang, Ji-Un, Yoo, Gyun Young, Kim, Seong Hun, Oh, Myung Jun, and Kim, Seong Yun
- Subjects
- *
THERMAL conductivity , *ELECTRIC conductivity , *POLYMER networks , *NANOPARTICLES , *GRAPHENE , *POLYMERS - Abstract
Introducing a segregated network constructed through the selective localization of small amounts of fillers can be a solution to overcome the limitations of the practical use of graphene-based conductive composites due to the high cost of fillers. In this study, polypropylene composites filled with randomly dispersed GNPs and a segregated GNP network were prepared, and their conductive properties were investigated according to the formation of the segregated structure. Due to the GNP clusters induced by the segregated structure, the electrical percolation threshold was 2.9 wt% lower than that of the composite incorporating randomly dispersed GNPs. The fully interconnected GNP cluster network inside the composite contributed to achieving the thermal conductivity of 4.05 W/m∙K at 10 wt% filler content. Therefore, the introduction of a segregated filler network was suitable to simultaneously achieve excellent electrical and thermal conductivities at a low content of GNPs. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
4. Estimation of sediment discharge using a tree-based model.
- Author
-
Jang, Eun-Kyung, Ji, Un, and Yeo, Woonkwang
- Subjects
- *
SEDIMENTS , *FLOW velocity , *WATERSHEDS , *GOODNESS-of-fit tests , *DATA mining - Abstract
The model tree (MT) approach, a data mining technique used to analyse relationships between input and output variables in a disordered and large database, was adopted in this study to predict sediment discharge with field measurement data. The derived models were analysed for accuracy according to the goodness of fit based on training, testing, and modelling processes. When the flow velocity, depth, water surface slope, channel width, and median bed material were selected as the river's system variables, the model results of sediment discharge resembled the measured values. The results demonstrate that developing and using the sediment discharge estimation with the MT constitutes the most effective method if long-term sediment data are of sufficient validity. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
5. Experimentation and Modeling of Reach-Scale Vegetative Flow Resistance due to Willow Patches.
- Author
-
Ji, Un, Järvelä, Juha, Västilä, Kaisa, and Bae, Inhyeok
- Subjects
- *
RIPARIAN plants , *WILLOWS , *PRESSURE sensors , *AQUATIC plants , *WOODY plants , *CHANNEL flow - Abstract
Reach-scale experiments simulating the physical characteristics of natural woody plants are required for the improved modeling of flow resistance in channels with instream and floodplain vegetation. The first aim of this study was to investigate the flow resistance caused by patches of foliated woody vegetation at low volumetric blockage factors (4% to 10%) under emergent conditions, as most studies on the effect of patchiness are limited to submerged aquatic plants. Experiments with nature-like willow patches were performed in a reach-scale outdoor flume, where the density and layout of the patches were altered. The bulk friction factors were based on the friction slopes, calculated using the water surface slopes and velocity heads measured by a set of high-accuracy pressure sensors under several flow conditions. Compared to unvegetated conditions, the patches increased the bulk friction factor by 1.7–5.5 times, depending on the patch density and blockage factor. The second aim of this study was to evaluate the performance of four momentum-based models in estimating the bulk friction factors in flows with such flexible patches. For this process, a methodological approach suited for patchy woody vegetation at reach scale was developed to determine the input parameters required in each model. Estimation results using the newly modified and parameterized formulas compared favorably to the experimental data, demonstrating more reliable performance for models explicitly addressing the reconfiguration of vegetation. Overall, this study provides a practical methodology for estimating flow resistance caused by complex distributions of woody riverine vegetation. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
6. Evolution systems and continuity equations for white noise functionals.
- Author
-
Ji, Un Cig
- Subjects
- *
FUNCTIONALS , *WHITE noise , *GAUSSIAN processes , *EQUATIONS , *QUANTUM noise , *DIFFERENTIAL equations - Abstract
In this paper, by applying the quantum decomposition of white noise functionals, the continuity equations for white noise functionals are reformulated as time inhomogeneous white noise differential equations. We establish a systematic study of the evolution systems whose infinitesimal generators are quadratic quantum white noises and then, as an application, we study the continuity equations for white noise functionals of which the coefficient has up to the first chaos (Gaussian process). The restriction for the coefficient is comparable (not necessarily equivalent) to the integrability condition of the exponential of the coefficient by Ambrosio and Figalli [J. Funct. Anal. 256, 179–214 (2009)] for the well-posedness of the continuity equation in the abstract Wiener space setting. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
7. Blockage effect of emergent riparian vegetation patches on river flow.
- Author
-
Bae, Inhyeok, Ji, Un, Järvelä, Juha, and Västilä, Kaisa
- Subjects
- *
RIPARIAN plants , *STREAMFLOW , *RELATIVE velocity , *FLOW velocity , *EMPIRICAL research - Abstract
• Experiments on flow resistance of foliated woody vegetation patches at reach-scale. • Reach-scale flow resistance controlled by patch geometry, less by canopy density. • Quantitative relationships for predicting flow resistance using blockage factors. Woody riparian vegetation typically clusters in patch form and increases flow resistance more significantly than individual plants. In this study, we examined the patchiness effects in non-submerged (emergent) conditions on the reach-scale flow resistance in field-scale experiments involving nature-like artificial willow patches. The patchiness characteristics of woody vegetation were systematically defined and classified using the canopy density, patch geometry described by cross-sectional and planar blockage areas, cross-sectional and volumetric blockage factors of the patches, and patch location in the cross-section. We developed quantitative relationships as empirical equations for estimating the vegetative flow resistance using blockage factors, that is, the area or volume fraction of canopy occupation. The results revealed that flow resistance due to emergent willow patches under relatively densely foliated and low volumetric blockage conditions was mostly explained by the blockage parameters and to a lower degree by the canopy density. In addition, it reveals the effects of the spatial distribution of flow and velocity by the relative position of patches, i.e., the flow resistance varies with different tendencies according to hydraulic conditions as the patch shifts from the channel centerline toward the bankside. This study provides reliable and practical relationships for estimating the flow resistance induced by riparian vegetation patches under reach-scale field conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
8. Effects of photobiomodulation on bone remodeling in an osteoblast–osteoclast co-culture system.
- Author
-
Hong, Ji-Un, Kwon, Jin-Ju, Heo, Soon Chul, Shin, Sang-Hun, Kim, Hyung Joon, and Lee, Jae-Yeol
- Abstract
The general bone anabolic effect of photobiomodulation (PBM) is largely accepted. As a result, PBM therapy is expected to be beneficial in the medical fields of dentistry and bone healing. However, most of the previous in vitro studies on PBM and bone metabolism were performed with single-cell cultures of osteoclast-lineage cells or osteoblast-lineage cells. In the present study, the bone-modulating effects of PBM were evaluated in an in vitro osteoblast/osteoclast co-culture system. Mouse bone marrow-derived macrophages (BMMs) and mouse calvarial pre-osteoblasts cells were purified and used as precursor cells for osteoclasts and osteoblasts, respectively. The PBM effects on single-cell culture of osteoclasts or osteoblasts as well as co-culture were examined by 1.2 J/cm2 low-level Ga-Al-As laser (λ = 808 ± 3 nm, 80 mW, and 80 mA; spot size, 1cm2; NDLux, Seoul, Korea) irradiation for 30 s at daily intervals throughout culture period. At the end of culture, the osteoclast differentiation and osteoblast differentiation were assessed by TRAP staining and ALP staining, respectively. The expressions of osteoclastogenic cytokines were evaluated by RT-PCR and Western blot analyses. Under the single-cell culture condition, PBM enhanced osteoblast differentiation but had minor effects on osteoclast differentiation. However, in the co-culture condition, its osteoblastogenic effect was maintained, and osteoclast differentiation was substantially reduced. Subsequent RT-PCR analyses and western blot results revealed marked reduction in receptor activator of NF-κB ligand (RANKL) expression and elevation in osteoprotegerin (OPG) expression by PBM in co-cultured cells. More importantly, these alterations in RANKL/OPG levels were not observed under the single-cell culture conditions. Our results highlight the different effects of PBM on bone cells based on culture conditions. Further, our findings suggest the indirect anti-osteoclastogenic effect of PBM, which is accompanied by a decrease in RANKL expression and an increase in OPG expression. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
9. Electrical conductivity of polymer composites based on carbonized wood flour via plasma post‐treatment as an effective and economical filler.
- Author
-
Kim, Woo Young, Jang, Ji‐un, Lee, Hun Su, and Kim, Seong Yun
- Subjects
- *
ELECTRIC conductivity , *WOOD flour , *POLYMERS , *MEDICAL care costs , *INDUSTRIAL costs , *CARBON-black - Abstract
The recycling of waste resources is not optional but rather essential to achieve a sustainable human future. In this study, the feasibility of carbonized wood flour (CWF) as a conductive filler was evaluated for improving the electrical conductivity of polymer composites because wood flour is a sustainable and promising precursor for CWF filler, as a naturally abundant and industrially steady resource. The optimized electrical conductivity of the composite with 25 wt% CWF post‐treated by the inductively coupled plasma (ICP), proposed in this study, was 71 S/m, exceeding that of the carbon black (CB)‐filled composite (12 S/m). In addition, the estimated production cost of ICP treated CWF ($1.35–1.55/kg) was about 22.5%–32.5% lower than that of commercial CB ($2/kg). Therefore, the CWF was an effective, economical, and eco‐friendly conductive filler to enhance the electrical conductivity of polymer composites. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
10. Fractional Langevin type equations for white noise distributions.
- Author
-
Ji, Un Cig, Lee, Mi Ra, and Ma, Peng Cheng
- Subjects
- *
LANGEVIN equations , *FRACTIONAL calculus , *FRACTIONAL powers , *CAPUTO fractional derivatives , *DISTRIBUTION (Probability theory) , *WHITE noise - Abstract
In this paper, by applying the intertwining properties, we introduce the fractional powers of the number operator perturbed by generalized Gross Laplacians (infinite dimensional Laplacians), which are special types of the infinitesimal generators of generalized Mehler semigroups. By applying the intertwining properties and semigroup approach, we study the Langevin type equations associated with the infinite dimensional Laplacians and with white noise distributions as forcing terms. Then we investigate the unique solution of the fractional Langevin type equations associated with the Riemann-Liouville and Caputo time fractional derivatives, and the fractional power of the infinite dimensional Laplacians, for which we apply the intertwining properties again. For our purpose, we discuss the fractional integrals and fractional derivatives of white noise distribution valued functions. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
11. Convex feasibility problems on uniformly convex metric spaces.
- Author
-
Choi, Byoung Jin, Ji, Un Cig, and Lim, Yongdo
- Subjects
- *
METRIC spaces , *FEASIBILITY studies - Abstract
In this paper, we extend two important notions, weighted average method and Mann's iterative method, in the study of convex feasibility problem for general maps defined on p-uniformly convex metric spaces. Then we prove the Δ-convergence theorems for the weighted average sequence and the Mann's alternating sequence in p-uniformly convex metric spaces. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
12. Facile and cost-effective strategy for fabrication of polyamide 6 wrapped multi-walled carbon nanotube via anionic melt polymerization of ε-caprolactam.
- Author
-
Jang, Ji-un, Lee, Hun Su, Kim, Jae Woo, Kim, Seong Yun, Kim, Seong Hun, Hwang, Inwoog, Kang, Byung Joo, and Kang, Myung Koo
- Subjects
- *
ADDITION polymerization , *POLYAMIDES , *POLYMERS , *ELECTROSTATIC discharges , *MANUFACTURING processes , *ELECTRIC conductivity - Abstract
• Facile and cost-effective fabrication of PA6 wrapped MWNTs was developed. • MWNTs were wrapped with PA6 via anionic polymerization of ε-caprolactam. • Tens of g units of PA6 wrapped MWNTs can be produced by the single fabrication. • MWNTs were more uniformly dispersed in composites by the solvent-free strategy. There is a growing demand for the development of a melt process-based nanocomposite manufacturing process capable of minimizing the incorporation of expensive carbon nanotubes (CNTs) by inducing a uniform dispersion of multi-walled CNTs (MWNTs). In this study, we proposed a nanocomposite manufacturing process that includes both physical particle mixing using high-speed rotation and anionic polymerization of ε-caprolactam (CL) to induce a uniform dispersion of MWNTs. MWNTs were uniformly dispersed by powder mixing and then wrapped with polyamide 6 polymers by in-situ polymerization of CL. The synergistic effect of the two sub-processes resulted in an enhanced dispersion of MWNTs and prevented aggregation of the MWNTs. The composites fabricated by the proposed process exhibited electrical conductivities of 4.49 × 10−5 S/m and 1.45 × 10 S/m at 1 wt% and 3 wt% MWNTs, respectively, indicating that by applying the proposed process it is possible to incorporate a smaller amount of MWNT to achieve electrical conductivities applicable for electrostatic discharge (ESD) (>1 X 10−5 S/m) and electromagnetic interference shielding effectiveness (EMI SE) (>10 S/m) applications. An ESD chip tray and EMI SE mobile phone case were fabricated using the prepared composite, and it was verified that the ESD and EMI SE performances can be realized. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
13. Characterization of S-transform for general construction of infinite-dimensional distributions.
- Author
-
Accardi, Luigi, Ji, Un Cig, and Saitô, Kimiaki
- Subjects
- *
WHITE noise theory , *WHITE noise - Abstract
We study the analytic characterization of S -transform in a general setting of white noise functionals. Then, the measurability condition of the norms generating the underlining locally convex space is a necessary and sufficient condition for the analytic characterization of the S -transform in terms of analytic and growth conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
14. Toeplitz lemma in geodesic metric space and convergence of inductive means.
- Author
-
Choi, Byoung Jin and Ji, Un Cig
- Subjects
- *
GEODESIC equation , *GEODESICS , *TOEPLITZ matrices , *TOEPLITZ operators , *DIFFERENTIAL geometry - Abstract
In this article, we study the Toeplitz lemma for inductive means in a geodesic metric space, and by using the Toeplitz lemma, we prove the Cesàro theorem for inductive means. Also, we study an asymptotic property for Hansen's inductive geometric mean, and as an application of the Toeplitz lemma, we prove a convergence of Hansen's inductive mean. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
15. Noncommutative Fuk-Nagaev Inequalities and Their Applications.
- Author
-
Choi, Byoung Jin and Ji, Un Cig
- Subjects
- *
RANDOM variables , *PROBABILITY theory , *LAW of large numbers , *MATHEMATICAL convolutions - Abstract
We establish a noncommutative extension of the Fuk-Nagaev inequalities for random variables in a noncommutative probability space. As applications, we first obtain noncommutative versions of Bennett inequality and Rosenthal inequality, and secondly, we study the weak law of large numbers for weighted sums in a noncommutative probability space and the weak law of large numbers for weighted sums of probability measures corresponding to the free additive convolutions. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
16. Inequalities for positive module operators on von Neumann algebras.
- Author
-
Choi, Byoung Jin, Ji, Un Cig, and Lim, Yongdo
- Subjects
- *
OPERATOR theory , *SCHWARZ inequality , *VON Neumann algebras , *SCHRODINGER operator , *NONCOMMUTATIVE differential geometry - Abstract
We establish the Cauchy-Schwarz and Golden-Thompson inequalities for module operators, a generalization of a (noncommutative) conditional expectation, on a von Neumann algebra. We apply these inequalities to the Bennett inequality and an uncertainty relation, a generalization of the Schrödinger uncertainty relation, for conditional expectations. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
17. Convergences of Alternating Projections in CAT(κ) Spaces.
- Author
-
Choi, Byoung Jin, Ji, Un Cig, and Lim, Yongdo
- Subjects
- *
STOCHASTIC convergence , *MATHEMATICAL sequences , *VON Neumann algebras , *COMPACT spaces (Topology) , *SET theory - Abstract
We establish the asymptotic regularity and the Δ
-convergence of the sequence constructed by alternating projections onto closed convex sets in a CAT(κ) space with κ>0 . Furthermore, the strong convergence of the alternating von Neumann sequence is presented under certain regularity or compactness conditons. [ABSTRACT FROM AUTHOR] - Published
- 2018
- Full Text
- View/download PDF
18. Quantum properties of classical Pearson random variables.
- Author
-
Accardi, Luigi, Ella, Abdon Ebang, Ji, Un Cig, and Lu, Yun Gang
- Abstract
This paper discusses the properties of the canonical quantum decomposition of the classical Pearson random variables. We show that this leads to the problem of representing the creation–annihilation–preservation (CAP) operators canonically associated to a real-valued random variable X with all moments as (normally ordered) differential operators with polynomial coefficients — a problem already studied in the literature (see references in the introduction). We deduce a formula, for the polynomial coefficients in the representation of the CAP operators of X as pseudo-differential operators, more explicit than the one existing in the literature. We give a new characterization of the Pearson distributions in terms of the Hermitianity of the associated Sturm–Liouville operators. In the second part of the paper, we introduce the notion of finite type random variable X and characterize type-2 and type-3 real-valued random variables. We prove that a necessary condition for X to be of finite type is the polynomial growth of the corresponding principal Jacobi sequence. This allows to single out three classes of random variables of infinite type and to prove that the Beta and the uniform distributions are of infinite type. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
19. True self-reinforced composites enabled by tuning of molecular structure for lightweight structural materials in future mobility.
- Author
-
Lee, Hyeseong, Jang, Ji-un, Kim, Jaewoo, Sang Kim, Yoon, Cho, Jaehyun, Na Kim, Mi, Tae Lee, Jung, Hyuk Choi, Woo, Man Song, Jong, June Song, Won, Hui Won, Dong, Woo Yun, Deok, Hun Kim, Seong, Kim, Minkook, and Yun Kim, Seong
- Subjects
- *
CONSTRUCTION materials , *MOLECULAR structure , *CARBON fiber-reinforced plastics , *UNIFORM polymers , *ELECTRIC insulators & insulation , *LIGHTWEIGHT materials - Abstract
[Display omitted] • True SRC concept using single polymer pellet without other materials was suggested. • A fiber with extremely oriented polymer chains was prepared by 1500% drawing. • Low molecular weight polymer chains with uniform chain lengths were prepared by QSE. • True SRC was achieved by combining the oriented fiber and chain-controlled matrix. • Adhesive, tensile and impact properties of the true SRC were improved innovatively. The development of vehicle bodies based on lightweight structural composites is urgently required to upgrade electric cars and to commercialize urban air mobility. Self-reinforced composites (SRCs) are attracting attention due to their advantages in terms of price, lightness, disposal and recycling compared to carbon fiber-reinforced polymers (CFRPs). In this study, a new concept for 100% polypropylene (PP) SRC was proposed to simultaneously improve the adhesive, tensile and impact properties of SRCs without undermining the advantages of SRCs. For this implementation, a facile engineering strategy using quad screw extrusion (QSE) capable of generating high shear stress was employed to modify the melting temperature and impregnation properties of the PP matrix via controlling polymer chain structure. As the screw rotation speed of QSE increased, low molecular weight polymer chains with uniform chain lengths were prepared, which led to a decrease in the melting temperature of the PP matrix and an increase in the flowability and impregnation property of the matrix. Using this strategy, the adhesive strength, tensile strength and impact resistance of the optimized SRC improved by 333%, 228%, and 2700%, respectively. Racing drone flight experiments with the SRC and CFRP frames illustrated the advantages of the SRC frame such as the increase of the flight time due to low density of the SRC, the excellent impact resistant characteristics (which improves user safety), and the superior electrical insulation properties suitable for frequency transmission and reception. Therefore, the proposed SRC can be an ideal choice as a lightweight structural material for future mobility. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
20. Analytic characterizations of infinite dimensional distributions.
- Author
-
Accardi, Luigi, Ji, Un Cig, and Saitô, Kimiaki
- Subjects
- *
DISTRIBUTION (Probability theory) , *DIMENSIONS , *MATHEMATICAL transformations , *WHITE noise , *FUNCTIONALS - Abstract
We revisit the analytic characterization theorem for S-transform of infinite dimensional distributions. Then we prove that the nuclearity of the space of test white noise functionals is a necessary condition for the characterization of the S-transform in terms of analytic and growth conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
21. Control of side reactions using LiNbO3 mixed/doped solid electrolyte for enhanced sulfide-based all-solid-state batteries.
- Author
-
Cho, Ji-Un, Rajagopal, Rajesh, Yoon, Da Hye, Park, Yong Joon, and Ryu, Kwang-Sun
- Subjects
- *
SOLID state batteries , *SUPERIONIC conductors , *SOLID electrolytes , *SCANNING transmission electron microscopy , *ENERGY dispersive X-ray spectroscopy , *INTERFACIAL reactions , *IONIC conductivity - Abstract
[Display omitted] • LiNbO 3 doped/mixed Li 6 PS 5 Cl argyrodite electrolyte prepared by ball mill method. • The addition LiNbO 3 of increase the conductivity at electrode – electrolyte interface. • The LiNbO 3 act as coating layer and enhance the electrochemical performance of ASSBs. Control of side reactions is a critical issue for obtaining all-solid-state lithium batteries (ASSLBs) with comparable performance to lithium-ion batteries (LIBs). In particular, the interfacial reaction at the cathode/sulfide electrolyte interface and decomposition of the sulfide electrolyte lead to a significant deterioration in the electrochemical performance of ASSLBs. Surface-coated cathodes have been used in ASSLBs to mitigate these side reactions. However, the generally used LiNbO 3 coating, a representative coating for ASSLBs, is expensive because of the high price of the source materials, and perfect coverage of the entire cathode surface by coating is practically very difficult. In this study, we introduced a LiNbO 3 mixed/doped Li 6 PS 5 Cl solid electrolyte, instead of surface coating on the cathodes, to improve the resistance against side reactions concerning the sulfide electrolyte. The source material used for LiNbO 3 mixing/doping is cheaper than that used for LiNbO 3 coating. Partial doping of LiNbO 3 was confirmed by laser Raman spectroscopy and field-emission scanning electron microscopy with energy dispersive X-ray spectroscopy (EDS) analysis. An optimum LiNbO 3 mixed/doped electrolyte (4 mol.% of electrolyte) showed enhanced ionic conductivity than that of Li 6 PS 5 Cl solid electrolyte without LiNbO 3. Moreover, the interfacial reaction at the cathode/electrolyte interface and the sulfide electrolyte decomposition were decreased owing to the LiNbO 3 mixing/doping effect. The suppression of ion exchange between the cathode and electrolyte was also confirmed by the scanning transmission electron microscopy - energy dispersive X-ray spectroscopy (STEM-EDS) line profile. These results contributed to the increased discharge capacity and improved rate capability of the cell using 96LPSCl-4LNO (4 mol.% LiNbO 3 mixing/doping), compared to those of the cell using pristine Li 6 PS 5 Cl. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
22. Exponential convergence rates for weighted sums in noncommutative probability space.
- Author
-
Choi, Byoung Jin and Ji, Un Cig
- Subjects
- *
STOCHASTIC convergence , *PROBABILITY theory , *NONCOMMUTATIVE algebras , *TOPOLOGY , *RING extensions (Algebra) - Abstract
We study exponential convergence rates for weighted sums of successive independent random variables in a noncommutative probability space of which the weights are in a von Neumann algebra. Then we prove a noncommutative extension of the result for the exponential convergence rate by Baum, Katz and Read. As applications, we first study a large deviation type inequality for weighted sums in a noncommutative probability space, and secondly we study exponential convergence rates for weighted free additive convolution sums of probability measures. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
23. Ergodic theorems for higher order Cesàro means.
- Author
-
Accardi, Luigi, Choi, Byoung Jin, and Ji, Un Cig
- Subjects
- *
LAW of large numbers , *BANACH spaces - Abstract
We investigate the convergence of higher order Cesàro means in Banach spaces. The main results of this paper are: (1) The proof of mean and Birkhoff-type ergodic theorems for higher order Cesàro means. (2) The existence of a one-to-one correspondence between convergent Cesàro means of different orders. (3) The proof of strong laws of large numbers for higher order sums of independent and identically distributed random elements. (4) A characterization of the ergodicity of measure preserving maps in terms of higher order mixing properties. To deal with higher order Cesàro means, one needs a notion of weighted mean more general than the one usually considered in the literature on weighted ergodic theorems. In this context, we also prove a characterization of generalized weighted means preserving Cesàro convergence. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
24. Delaying diagnostic procedure significantly increases mortality in patients with invasive mucormycosis.
- Author
-
Jeong, Su Jin, Lee, Ji Un, Song, Young Goo, Lee, Kyoung Hwa, and Lee, Min Joo
- Subjects
- *
MUCORMYCOSIS , *ANTIFUNGAL agents , *MORTALITY , *DIAGNOSIS , *KIDNEY failure - Abstract
Invasive mucormycosis is an uncommon but increasing life-threatening fungal infection. The present study investigated clinical characteristics and mortality among patients diagnosed as invasive mucormycosis infection. We retrospectively reviewed a total of 24 histologically proven cases of invasive mucormycosis at two tertiary care referral hospitals between November 2005 and February 2014. Overall survival was 50% ( n = 12). The time between onset of symptom and diagnostic procedure proved to be associated with mortality ( P = 0.009). In addition, preexisting renal failure and thrombocytopenia demonstrated trends toward a poor outcome in our study ( P = 0.089 and 0.065, respectively). On multivariate regression analysis, delayed diagnostic procedure (more than 16 days after the onset of symptoms) was an independent predictor of mortality (OR= 12.34, 95% CI, 1.43-10.64; P = 0.022). Mucormycosis is a destructive fungal infection that is associated with high mortality rates, ranging from 40% to 100% depending on the form of disease. When a clinician suspects invasive mucormycosis infection, an early diagnostic procedure performed within 16 days from the onset of symptom and early initiation of antifungal therapy will lead to successful management of this highly fatal disease. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
25. Higher order multi-dimensional extensions of Cesàro theorem.
- Author
-
Accardi, Luigi, Ji, Un Cig, and Saitô, Kimiaki
- Subjects
- *
HIGHER order transitions , *MULTIDIMENSIONAL databases , *CONTINUOUS functions , *DIMENSIONAL analysis , *DISCRETE-time systems - Abstract
The Cesàro theorem is extended to the cases: (1) higher order Cesàro mean for sequence (discrete case); and (2) higher order, multi-dimensional and continuous Cesàro mean for functions. Also, we study the Cesàro theorem for the case of positive-order. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
26. Thermal conductivity of polymer composites based on the length of multi-walled carbon nanotubes.
- Author
-
Kim, Hyun Su, Jang, Ji-un, Yu, Jaesang, and Kim, Seong Yun
- Subjects
- *
THERMAL conductivity , *POLYMERIC composites , *MULTIWALLED carbon nanotubes , *INTERFACIAL resistance , *SIMULATION methods & models - Abstract
The anisotropic development of thermal conductivity in polymer composites was evaluated by measuring the isotropic, in-plane and through-plane thermal conductivities of composites containing length-adjusted short and long multi-walled CNTs (MWCNTs). The thermal conductivities of the composites were relatively low irrespective of the MWCNT length due to their high contact resistance and high interfacial resistance to polymer resins, considering the high thermal conductivity of MWCNTs. The isotropic and in-plane thermal conductivities of long-MWCNT-based composites were higher than those of short-MWCNT-based ones and the trend can accurately be calculated using the modified Mori-Tanaka theory. The in-plane thermal conductivity of composites with 2 wt% long MWCNTs was increased to 1.27 W/m·K. The length of MWCNTs in polymer composites is an important physical factor in determining the anisotropic thermal conductivity and must be considered for theoretical simulations. The thermal conductivity of MWCNT polymer composites can be effectively controlled in the processing direction by adjusting the length of the MWCNT filler. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
27. Chromosome 8q as the most frequent target for amplification in early gastric carcinoma.
- Author
-
JI UN KANG
- Subjects
- *
CHROMOSOMES , *STOMACH cancer , *ONCOGENES , *NEOPLASTIC cell transformation , *TRANSCRIPTION factors - Abstract
Early gastric carcinoma (GC) is considered to be a curable cancer, as it progresses to the advanced stage following varying durations. Understanding the early stage of GC may provide an insight into its pathogenesis and contribute to reducing the mortality rate of this disease. To investigate the genomic aberrations associated with 22 cases of early GC, high-density microarray comparative genomic hybridization was performed in the present study. The most notable finding was copy number gains (log2 ratio >0.25) on the long arm of chromosome 8, which occurred in 77.3% (17/22) of GC cases, and the delineated minimal common region was 8q22.1-q24.3. More specifically, two amplified (log2 ratio >1) loci in the 8q22.1-q24.3 region were detected in 18.2% (4/22) of GC cases. The first loci covered a region of 102.4-107.9 kb, mapping on 8q22.3-q23.1, and comprised the transcription factor CP2-like 3 gene. The second loci, spanning 128.7-145.7 kb on 8q24.21-q24.3, comprised the representative oncogene of myelocytomatosis. Furthermore, the following possible target genes that were not previously considered to play a pathogenic role in GC were identified: Plasmacytoma variant translocation 1, cysteine/histidine rich 1, kinesin family member C2, forkhead box H1, protein phosphatase 1 regulatory subunit 16A, glutamic-pyruvate transaminase, LOC113655 and RecQ protein-like 4. In the present study, previous findings showing that 8q mutations accumulate early during the multistage pathogenesis of GC were confirmed and expanded upon. The confirmation of previously reported 8q gains and the identification of novel target genes at 8q22.1-q24.3 amplified chromosomal sites should aid in improving our understanding of the molecular mechanisms underlying the tumorigenesis of early GC. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
28. Risk assessment of watershed erosion at Naesung Stream, South Korea.
- Author
-
Ji, Un, Velleux, Mark, Julien, Pierre Y., and Hwang, Manha
- Subjects
- *
SOIL erosion research , *SEDIMENTATION & deposition research , *ENVIRONMENTAL risk assessment , *SIMULATION methods & models , *SPATIO-temporal variation , *WATERSHEDS , *MATHEMATICAL models - Abstract
A three-tiered approach was used to assess erosion risks within the Nakdong River Basin in South Korea and included: (1) a screening based on topography and land use; (2) a lumped parameter analysis using RUSLE; and (3) a detailed analysis using TREX, a fully distributed watershed model. These tiers span a range of spatial and temporal scales, with each tier providing increasing detail and resolution. The first two tiers were applied to the entire Nakdong River Basin and the Naesung Stream watershed was identified as having the highest soil erosion risk and potential for sedimentation problems. For the third tier, the TREX watershed model simulated runoff, channel flow, soil erosion, and stream sediment transport in the Naesung Stream watershed at very high resolution. TREX was calibrated for surface flows and sediment transport, and was used to simulate conditions for a large design storm. Highly erosive areas were identified along ridgelines in several headwater areas, with the northeast area of Songriwon having a particularly high erosion potential. Design storm simulations also indicated that sediment deposition of up to 55 cm could occur. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
29. Convergence rates for weighted sums in noncommutative probability space.
- Author
-
Choi, Byoung Jin and Ji, Un Cig
- Subjects
- *
STOCHASTIC convergence , *NONCOMMUTATIVE algebras , *PROBABILITY theory , *RANDOM variables , *VON Neumann algebras , *LORENTZ spaces - Abstract
Abstract: We study convergence rates for weighted sums of pairwise independent random variables in a noncommutative probability space of which the weights are in a von Neumann algebra. As applications, we first study convergence rates for weighted sums of random variables in the noncommutative Lorentz space, and second we study convergence rates for weighted sums of probability measures with respect to the free additive convolution. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
30. Analytical and Experimental Investigation of a Side-Weir Detention Basin in Flood-Level Reduction in the Main Channel.
- Author
-
Ji, Un, Kim, Seojun, Yoon, Byungman, and Kim, Sanghyuk
- Subjects
- *
STORM water retention basins , *RUNOFF , *UNSTEADY flow , *WEIRS , *HYDRAULIC structures - Abstract
To design the off-stream detention basin by the sides of rivers or channels, flood-level reduction in main channels should be evaluated under unsteady flow. Flow discharge diverted to the side weir from the main stream can be calculated practically by the standard weir or lateral weir equations. In this study, experimental and numerical modeling with a side-weir detention basin was conducted for unsteady flow. The experimental results were compared with the numerical backwater profile calculation considering the water discharge overflowed into the basin from the channel. The overflowed discharge was estimated by the standard weir and lateral weir equations for various flow types at the side weir. The standard weir equation accurately predicted flow discharge diverted to the side weir for free overflow condition. The lateral weir equation calculated a precise flood level and time of peak flow for the condition modeled, especially when the various flows, including free and submerged overflows, were developed at the side weir. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
31. Thermal Percolation Behavior in Thermal Conductivity of Polymer Nanocomposite with Lateral Size of Graphene Nanoplatelet.
- Author
-
Jang, Ji-un, Nam, Hae Eun, So, Soon Oh, Lee, Hyeseong, Kim, Geon Su, Kim, Seong Yun, and Kim, Seong Hun
- Subjects
- *
THERMAL conductivity , *PERCOLATION , *NANOCOMPOSITE materials , *GRAPHENE , *POLYMERS , *POLYMER networks - Abstract
In this study, the thermal percolation behavior for the thermal conductivity of nanocomposites according to the lateral size of graphene nanoplatelets (GNPs) was studied. When the amount of GNPs reached the critical concentration, a rapid increase in thermal conductivity and thermal percolation behavior of the nanocomposites were induced by the GNP network. Interestingly, as the size of GNPs increased, higher thermal conductivity and a lower percolation threshold were observed. The in-plane thermal conductivity of the nanocomposite containing 30 wt.% M25 GNP (the largest size) was 8.094 W/m·K, and it was improved by 1518.8% compared to the polymer matrix. These experimentally obtained thermal conductivity results for below and above the critical content were theoretically explained by applying Nan's model and the percolation model, respectively, in relation to the GNP size. The thermal percolation behavior according to the GNP size identified in this study can provide insight into the design of nanocomposite materials with excellent heat dissipation properties. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
32. Preparation of highly conductive metal doped/substituted Li7P2S8Br(1-x)Ix type lithium superionic conductor for all-solid-state lithium battery applications.
- Author
-
Rajagopal, Rajesh, Cho, Ji-Un, Subramanian, Yuvaraj, Jung, Yu Jin, Kang, Sung, Ha, Yoon-Cheol, and Ryu, Kwang-Sun
- Subjects
- *
SOLID state batteries , *SUPERIONIC conductors , *SOLID electrolytes , *LITHIUM cells , *IONIC conductivity , *METALS , *LITHIUM sulfur batteries , *TIN - Abstract
• Li 7 P 2 S 8 Br (1-x) I x type mixed halide solid electrolytes prepared by ball mill method. • Li 7 P 2 S 8 Br 0.25 I 0.75 solid electrolyte exhibited the ionic conductivity of 6.16 mS/cm. • Sn doped Li 7 P 2 S 8 Br 0.25 I 0.75 exhibited the high ionic conductivity of 7.78 mS/cm. • The formation of P42 nmc phase and Sn doping was confirmed by NMR and XRD analysis. Sulfide-based lithium superionic conducting solid electrolytes for all-solid-state lithium batteries have received much attention due to their high safety, ionic conductivity, and compatibility. However, high-temperature treatment over a long time is needed to achieve high ionic conductivity. In this work, we have prepared the dual-halide-based Li 7 P 2 S 8 X type lithium superionic conductors by dry ball mill process and the high ionic conducting phase was achieved by low temperature (200℃) heat-treatment process. High ionic conducting halogen-halogen composition was arrived at through a series of optimization processes. Among the compositions tested, the Li 7 P 2 S 8 Br 0.25 I 0.75 solid electrolyte exhibited a high ionic conductivity value of 6.16 mS cm−1, at room temperature. The ionic radius of the halogen element played an important role in the formation of the high ionic conducting phase. Further, the ionic conductivity of Li 7 P 2 S 8 I 0.75 Br 0.25 solid electrolyte was improved by metal doping at P-site. The Sn-doped Li 7 P 2 S 8 I 0.75 Br 0.25 solid electrolyte exhibited a high ionic conductivity value of 7.78 mS cm−1, at room temperature. The addition of large-sized Sn atoms extended the crystal lattice parameters and increased the Li-ions transport path. The partial substitution of Sn atoms at P-site was confirmed by NMR and Laser Raman analysis. The electrochemical stability of the prepared solid electrolyte was studied by cyclic voltammetry and DC charge-discharge analysis. The addition of a metal atom to the Li 7 P 2 S 8 Br 0.25 I 0.75 solid electrolyte decreased the side reaction with the Li metals. Thus, low-temperature treated metal-doped Li 7 P 2 S 8 Br 0.25 I 0.75 solid electrolytes are highly favourable for the fabrication of high-performance all-solid-state batteries. The fabricated all-solid-state battery using Sn doped Li 7 P 2 S 8 Br 0.25 I 0.75 solid electrolyte exhibited the high specific capacity value of 170 mAh g−1 (0.1C), at room temperature. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
33. Characterization of amplification patterns and target genes on the short arm of chromosome 7 in early-stage lung adenocarcinoma.
- Author
-
JI UN KANG
- Subjects
- *
ADENOCARCINOMA , *LUNG cancer , *DISEASE progression , *CHROMOSOMES , *ONCOGENES - Abstract
Chromosomal alterations are a predominant genomic force contributing to the development of lung adenocarcinoma (ADC). High density genomic arrays were conducted to identify critical genetic landmarks that may be important mediators in the formation or progression of early-stage ADC. In this study, the most noteworthy and consistent observation was a copy number gain on the short arm of chromosome 7, which was detected in 85.7% (12/14) of cases. Notably, three distinct regions of amplification were identified between the 7p22.3 and q11.2 regions in 28.6% (4/14) of cases; at a size of 4.1 Mbp (7p22.3-p21.1), 2.6 Mbp (7p15.2-p14.1) and 1.5 Mbp (7p12.3-p11.2). Variations of the 7p11.2 locus that encodes EGFR are known to be oncogenic. Furthermore, potential target genes were identified that were previously not assumed to be involved in the pathogenesis of ADC, including CALM1P2 (7p11.2), HOXA4, HOXA5, HOXA6, HOXA7, HOXA9, HOXA10, HOXA11 and HOXA13 (7p15.2) and LOC442586, LOC442589, LOC442282, FAM20C and LOC442651 (7p22.3). The present study determined critical regions on the 7p arm of chromosome 7, which were implicated in ADC. The pattern of rearrangements on the 7p arm may be a consequence of the high density of potential targets and the identified genes at the 7p regions may aid in the development of therapeutic targets for ADC. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
34. THE EXOTIC (HIGHER ORDER LEVY) LAPLACIANS GENERATE THE MARKOV PROCESSES GIVEN BY DISTRIBUTION DERIVATIVES OF WHITE NOISE.
- Author
-
ACCARDI, LUIGI, JI, UN CIG, and SAITÔ, KIMIAKI
- Subjects
- *
LEVY processes , *LAPLACIAN matrices , *MARKOV processes , *DISTRIBUTION (Probability theory) , *DERIVATIVES (Mathematics) , *HILBERT space , *GENERALIZATION , *WHITE noise - Abstract
We introduce, for each a ... R+, the Brownian motion associated to the distribution derivative of order a of white noise. We prove that the generator of this Markov process is the exotic Laplacian of order 2a, given by the Cesàro mean of order 2a of the sec-ond derivatives along the elements of an orthonormal basis of a suitable Hilbert space (the Cesàro space of order 2a). In particular, for a = 1/2 one finds the usual Lévy Laplacian, but also in this case the connection with the 1/2-derivative of white noise is new. The main technical tool, used to achieve these goals, is a generalization of a result due to Accardi and Smolyanov5 extending the well-known Cesàro theorem to higher order arithmetic means. These and other estimates allow to prove existence of the heat semi-group associated to any exotic Laplacian of order ≥1/2 and to give its explicit expression in terms of infinite dimensional Fourier transform. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
35. Covariant representations on Krein -modules associated to pairs of two maps
- Author
-
Heo, Jaeseong, Ji, Un Cig, and Kim, Young Yi
- Subjects
- *
REPRESENTATIONS of algebras , *HILBERT modules , *MATHEMATICAL mappings , *CROSSED products of algebras , *DISCRETE groups , *MATHEMATICAL analysis - Abstract
Abstract: In this paper we construct a KSGNS type covariant representation on a Krein -module for a covariant -completely positive map, and the result is applied to construct a KSGNS type covariant representation associated with a pair of two maps where is a covariant -completely positive map on a -algebra and is a covariant -map on a Krein -module. The KSGNS type covariant representation for a pair is applied to give a new covariant -representation of a crossed product of a -algebra and a new covariant map of a crossed product of a Hilbert -module by a discrete group. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
36. [lowercase_phi_synonym]-Derivations on operators on q-Fock space.
- Author
-
Ji, Un Cig and Kim, Jae Hee
- Subjects
- *
OPERATOR theory , *TOPOLOGICAL spaces , *DERIVATIVES (Mathematics) , *HOMOMORPHISMS , *QUANTUM theory , *WHITE noise theory , *MARTINGALES (Mathematics) - Abstract
We study the q-creation and q-annihilation derivatives of operators on q-Fock space and then the derivatives are [lowercase_phi_synonym]-derivations with respect to the q-Wick product, where [lowercase_phi_synonym] is a *-homomorphism with respect to the q-Wick product, which provide interesting non-trivial examples of abstract [lowercase_phi_synonym]-derivation. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
37. Quantum stochastic processes for maps on Hilbert C*-modules.
- Author
-
Heo, Jaeseong and Ji, Un Cig
- Subjects
- *
QUANTUM theory , *STOCHASTIC processes , *MATHEMATICAL mappings , *HILBERT algebras , *C*-algebras , *MODULES (Algebra) , *REPRESENTATIONS of algebras , *SEMIGROUPS (Algebra) - Abstract
We discuss pairs ([lowercase_phi_synonym], [uppercase_phi_synonym]) of maps, where [lowercase_phi_synonym] is a map between C*-algebras and [uppercase_phi_synonym] is a [lowercase_phi_synonym]-module map between Hilbert C*-modules, which are generalization of representations of Hilbert C*-modules. A covariant version of Stinespring's theorem for such a pair ([lowercase_phi_synonym], [uppercase_phi_synonym]) is established, and quantum stochastic processes constructed from pairs ({[lowercase_phi_synonym]t}, {[uppercase_phi_synonym]t}) of families of such maps are studied. We prove that the quantum stochastic process J = {Jt} constructed from a [lowercase_phi_synonym]-quantum dynamical semigroup [uppercase_phi_synonym] = {[uppercase_phi_synonym]t} is a j-map for the quantum stochastic process j = {jt} constructed from the given quantum dynamical semigroup [lowercase_phi_synonym] = {[lowercase_phi_synonym]t}, and that J is covariant if the [lowercase_phi_synonym]-quantum dynamical semigroup [uppercase_phi_synonym] is covariant. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
38. EXOTIC LAPLACIANS AND DERIVATIVES OF WHITE NOISE.
- Author
-
ACCARDI, LUIGI, JI, UN CIG, SAITÔ, KIMIAKI, and Obata, N.
- Subjects
- *
LAPLACIAN operator , *WHITE noise theory , *MATHEMATICAL singularities , *FUNCTIONAL analysis , *LEVY processes , *LINEAR operators , *CONTINUOUS functions - Abstract
In this paper, we give a relationship between the exotic Laplacians and the Lévy Laplacians in terms of the higher-order derivatives of white noise by introducing a bijective and continuous linear operator acting on white noise functionals. Moreover, we study a relationship between exotic Laplacians, acting on higher-order singular functionals, each other in terms of the constructed operator. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
39. A comparative study on the rumen microbial populations, hydrolytic enzyme activities and dry matter degradability between different species of ruminant.
- Author
-
MOON, Yea Hwang, OK, Ji Un, LEE, Shin Ja, HA, Jong Kyu, and LEE, Sung Sill
- Subjects
- *
RUMEN microbiology , *COMPARATIVE studies , *HYDROLASES , *RUMINANTS , *ANIMAL species , *CATHETERIZATION , *BIOMARKERS , *MICROORGANISM populations - Abstract
A comparative study among Korean native cow (Hanwoo), Holstein dairy cow, Korean native goat and crossbred sheep on the population and marker concentration of ruminal microbes, the activities of carboxymethylcellulase (CMCase), xylanase and amylase, and in situ dry matter (DM) degradability were conducted. Twelve ruminally cannulated animals, three of each species, were used. Animals were fed the same diet containing 40% formula feed and 60% rice straw at the level of 2.5% of body weight. Total viable microbial populations in the rumen fluid were significantly ( P < 0.01) greater for bacteria and fungi in goat than those of Holstein. The protozoan population among ruminant species was the reverse from that of bacteria. The concentrations of 2,6-diaminopimelic acid and chitin as markers for bacteria and fungi in the rumen fluid, respectively, were highest in goat, which is in accordance with the above population data. The concentration of aminoethylphosphonic acid as marker of protozoa was highest in Hanwoo and lowest in sheep ( P < 0.01). Goat had the highest ( P < 0.01) activities of all the enzymes investigated among ruminants. In situ effective degradation of the DM of rice straw was approximately 19% higher in the rumen of goat compared with other animals. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
40. Implementation problem for the canonical commutation relation in terms of quantum white noise derivatives.
- Author
-
Ji, Un Cig and Obata, Nobuaki
- Subjects
- *
COMMUTATION relations (Quantum mechanics) , *WHITE noise theory , *QUANTUM theory , *OPERATOR theory , *NUMERICAL solutions to differential equations , *BOSONS , *HILBERT space , *HERMITIAN operators - Abstract
The implementation problem for the canonical commutation relation is reduced to a system of differential equations for Fock space operators containing new type of derivatives. We solve these differential equations systematically by means of quantum white noise calculus, and obtain the solution to the implementation problem. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
41. Radon-Nikodým type theorem for α-completely positive maps.
- Author
-
Heo, Jaeseong and Ji, Un Cig
- Subjects
- *
FUNCTIONAL analysis , *MATHEMATICAL mappings , *CORRESPONDENCE analysis (Statistics) , *POSITIVE operators , *ANALYSIS of covariance , *MATHEMATICAL analysis , *MATHEMATICAL physics - Abstract
We introduce a new notion of α-completely positive map on a C*-algebra as a generalization of the notion of completely positive map. Then we study a theorem of the Radon-Nikodým type that there is a one-to-one correspondence between α-completely positive maps and positive operators and, as an application of the Radon-Nikodým type theorem, we give a characterization of pure α-completely positive maps. Finally, we study a covariant version of the Stinespring's theorem for a covariant α-completely positive map (see Theorem 4.3). [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
42. Effect of electrolyte in electrospun poly(vinylidene fluoride-co-hexafluoropropylene) nanofibers on dye-sensitized solar cells
- Author
-
Kim, Ji-Un, Park, Sung-Hae, Choi, Hyong-Ju, Lee, Won-Ki, Lee, Jin-Kook, and Kim, Mi-Ra
- Subjects
- *
DYE-sensitized solar cells , *POLYELECTROLYTES , *ELECTROSPINNING , *NANOFIBERS , *PROPENE , *ELECTRIC conductivity , *POROUS materials , *PHOTOVOLTAIC power generation , *IODINE - Abstract
Abstract: We prepared poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofibers by the electrospinning method and applied to the polymer matrix in polymer electrolytes for dye-sensitized solar cells (DSSCs). The uptake, ionic conductivity, and porosity of the electrospun PVDF-HFP nanofiber films showed 653±50%, 4.53±1.3×10−3 S/cm, and 70±2.3%, respectively, regardless of the diameter and morphology of nanofibers. In addition, several DSSC devices using the electrospun PVDF-HFP nanofiber films as the polymer matrix were prepared to investigate the photovoltaic effect of iodine (I2) concentrations on DSSC devices. With an increase of I2 concentration in electrolyte solutions, the ionic conductivity increased, while the photocurrent density of DSSC devices decreased. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
43. Nano-bridge effect on thermal conductivity of hybrid polymer composites incorporating 1D and 2D nanocarbon fillers.
- Author
-
Jang, Ji-un, Lee, Seung Hwan, Kim, Jaewoo, Kim, Seong Yun, and Kim, Seong Hun
- Subjects
- *
THERMAL conductivity , *THERMAL interface materials , *THERMAL properties , *POLYMERS , *POLYMERIC composites - Abstract
Numerous studies have been reported on thermal interface materials based on synergistic hybrid effects, however, most of them contain only fragmentary experimental results and the related model has been rarely proposed to explain the effects exactly. Herein, the thermal conductivities of the composites were systematically evaluated according to various filler contents and ratios. It was found that the fraction of the secondary filler inducing the maximum synergistic effect decreased as the total filler content increased. In addition, when the fraction was higher than the optimum fraction, the anti-synergistic effect occurred. At the optimum fraction, effective phonon transfer was induced due to the improved filler network formation of graphene nanoplatelet (GNP)-carbon nanotube (CNT), thereby achieving high thermal conductivity of 7.69 W/m·K at f GNP = 27.69 vol% and f CNT = 0.57 vol%. Moreover, the Kim-Jang-Lee (KJL) model for the synergistic effect was proposed by introducing filler-ratio variables into the critical percolation equation reported previously, and the KJL model for the anti-synergistic effect was proposed based on the rule of mixture of composites filled with the optimal connected filler network and filled with the excessive secondary filler. [Display omitted] • Optimum filler ratio determining hybrid effects was revealed. • Switching mechanism on synergistic and anti-synergistic effects was identified. • Synergistic increase in thermal conductivity was caused by the nano-bridge. • Excessive secondary filler in nanocomposites caused an anti-synergistic reduction. • New KJL model for the nano-bridge effect was proposed. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
44. Gain of the EGFR gene located on 7p12 is a frequent and early event in squamous cell carcinoma of the lung
- Author
-
Kang, Ji Un, Koo, Sun Hoe, Kwon, Kye Chul, Park, Jong Woo, and Jung, Sung Su
- Subjects
- *
GENES , *SQUAMOUS cell carcinoma , *CHROMOSOMES , *LUNG cancer - Abstract
Abstract: Identification of molecular alterations in biological fluids has been proposed as a powerful tool for cancer diagnosis. The purpose of this study was to identify cells that carry chromosomal alterations indicative of malignancy—specifically, gains in the loci 5p15.2 (D5S23, D5S721), 6p11∼q11, 7p12 (EGFR), and 8q24.12∼q24.13 (MYC)—for the detection of lung cancer using induced sputum. The overall sensitivity of the multicolor fluorescence in situ hybridization (FISH) assay from 52 lung cancer patients was 71% and the specificity was 100% (15 of 15). The most frequently detected gains were at 7p12 (EGFR) in 17 of 24 completely resectable early-stage (II+IIIA) non-small cell lung cancers (NSCLC) (71%). There was a statistically significant increase in the proportion of cases with gains of EGFR in squamous cell carcinomas (SCC), compared with adenocarcinomas (AC) (82 vs. 43%, respectively; P = 0.017), and a higher average EGFR gene copy number in the SCCs than in the ACs (5.04 vs. 3.78, respectively; P = 0.013) in 41 NSCLCs. Conversely, a gain at the 6p11∼q11 and 8q24.12∼q24.13 (MYC) regions appears to have a higher frequency of gain in the ACs (71 and 86%, respectively) than in the SCCs (48 and 56%, respectively). The results of this study showed the potential utility of the LAVysion FISH assay for the detection of lung cancer by a noninvasive technique based on the analysis of genetic alterations of induced sputum. Defining abnormalities in sputum specimens as FISH aneusomy may be a possible diagnostic method for the early detection of lung cancer in screening of high-risk populations and monitoring for recurrence. [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
- View/download PDF
45. Gain at chromosomal region 5p15.33, containing TERT, is the most frequent genetic event in early stages of non-small cell lung cancer
- Author
-
Kang, Ji Un, Koo, Sun Hoe, Kwon, Kye Chul, Park, Jong Woo, and Kim, Jin Man
- Subjects
- *
HUMAN cytogenetics , *CANCER genetics , *LUNG cancer , *CANCER patients - Abstract
Abstract: Chromosomal imbalances resulting in altered gene dosage play a role in the molecular pathogenesis of non-small cell lung cancer (NSCLC), but the target genes remain to be identified. To identify early-stage genetic events that drive progression of NSCLC, we conducted a high-resolution array comparative genomic hybridization (CGH) study, using an array of 4,046 bacterial artificial chromosome clones to screen for DNA copy number changes associated with individual genes in 36 tumors obtained from patients in early stages of NSCLC. Multiple early genetic events occurring on chromosome 5p were identified, with a minimal detection region at 5p15.33∼12. The most frequent finding involved gain of 5p15.33, observed in 15 of 19 stage I (A+B) cancers (79%) and in 28 of the total 36 NSCLC cases (78%). This locus harbors the genes TERT, SLC6A19, and SLC6A18 and is a telomeric boundary at bacterial artificial chromosome (BAC) clone 91_J20. Other potential candidate genes evidencing high numbers of genomic copy number changes (≥40% of patients) included the following genes, encountered in >50% of 19 stage I (A+B) cancers: CEP72 and TPPP (14 of 19; 74%); AHRR, EXOC3 (previously SEC6L1), SLC9A3, LOC442126, ZDHHC11, BRD9, and TRIP13 (13/19; 68%); and CLPTM1L (alias CRR9), SLC6A3 (previously DAT1), and LOC401169 (10/19; 53%). Fluorescence in situ hybridization validated the array CGH findings. The gain of 5p15.33 is thus one of the most consistent alterations in the early stages of lung cancer, and a series of genes in the critical 5p15.33 region may be used as novel biomarkers for the early detection and classification of lung cancer. [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
- View/download PDF
46. Unitary multiplier and dilation of projective isometric representation
- Author
-
Ji, Un Cig, Kim, Young Yi, and Park, Su Hyung
- Subjects
- *
OPERATOR functions , *FUNCTIONAL analysis , *OPERATOR theory , *FUNCTIONAL equations - Abstract
Abstract: In this paper we study unitary operator-valued multiplier σ on a normal subsemigroup S of a group G with its extension to G. A dilation of a projective isometric σ-representations of S to a projective unitary -representation of G is established for a suitable unitary operator-valued multiplier associated with the multiplier σ which is explicitly constructed during the study. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
47. Quantum Lévy Laplacian and associated heat equation
- Author
-
Ji, Un Cig, Obata, Nobuaki, and Ouerdiane, Habib
- Subjects
- *
PARABOLIC differential equations , *PARTIAL differential equations , *HEAT equation , *REACTION-diffusion equations - Abstract
Abstract: As a non-commutative extension of the Lévy Laplacian for entire functions on a nuclear space, we define the quantum Lévy Laplacian acting on white noise operators. We solve a heat type equation associated with the quantum Lévy Laplacian and study its relation to the classical Lévy heat equation. The solution to the quantum Lévy heat equation is obtained also from a normal-ordered white noise differential equation involving the quadratic quantum white noise. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
48. Photovoltaic Properties of Dye-Sensitized Solar Cells with Thermal Treated PEDOT:PSS as Counter Electrodes.
- Author
-
Park, Sung-Hae, Ji-Un Kim, Jin-Kook Lee, and Mi-Ra Kim
- Subjects
- *
PHOTOVOLTAIC cells , *POLYMERS , *MOLECULAR crystals , *ORGANIC thin films , *THIN film transistors , *ELECTROCHEMICAL analysis - Abstract
The dye-sensitized solar cell devices using PEDOT:PSS films as counter electrodes have the lower production cost and more simple fabrication process than devices using Pt counter electrode. To enhance the power conversion efficiency of devices, we fabricated DSSC devices using thermal treated poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) as counter electrodes. The power conversion efficiency of DSSC device using a counter electrode based PEDOT:PSS film treated at 45°C for 720 min achieved a value of 3.22%. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
49. UNIQUENESS OF INTEGRANDS IN QUANTUM STOCHASTIC INTEGRAL.
- Author
-
JI, UN CIG and SINHA, KALYAN B.
- Subjects
- *
INTEGRAL representations , *MARTINGALES (Mathematics) , *STOCHASTIC processes , *HILBERT space , *GENERALIZED inverses of linear operators - Abstract
As a general study for uniqueness of integrands in quantum martingale representation, we present a necessary and sufficient condition for uniqueness of integrands in a quantum stochastic integral. Also, several equivalent conditions to the necessary and sufficient condition are studied. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
50. Multitarget fluorescence in situ hybridization and melanoma antigen genes analysis in primary bladder carcinoma
- Author
-
Kang, Ji Un, Koo, Sun Hoe, Jeong, Tae Eun, Kwon, Kye Chul, Park, Jong Woo, and Jeon, Chang Ho
- Subjects
- *
IN situ hybridization , *KARYOKINESIS , *CLINICAL pathology , *HISTOPATHOLOGY - Abstract
Abstract: Conventional urine cytology has a poor prognostic performance for detecting bladder cancer, particularly for low-grade tumors. Fluorescence in situ hybridization (FISH) for chromosomes altered in bladder cancer and testing for antigens selectively expressed in tumors are promising alternatives. This study investigated the use of FISH for detecting aneuploidy of chromosomes 3, 7, 17, and 9p21 and reverse transcriptase PCR (RT-PCR) for the expression of melanoma associated antigen (MAGE) genes for the diagnosis of bladder cancer in voided urine specimens. The two techniques were compared with cystoscopic bladder biopsy results in 47 patients with urothelial cancer and 15 patients with benign prostatic hyperplasia. FISH detected cancer in 42 of 47 patients (89.4%). This was significantly higher than the detection rate 30 of 47 patients (64.3%) by MAGE RT-PCR (P < 0.001). The sensitivity of FISH increased with histologic grade and stage of the tumors, correctly identifying 77.8% of pTa and pTis, 94.1% of pT1, and 100% of Pt2–4 tumors. MAGE, however, showed a decreased sensitivity in high grade advanced tumors; it was positive in 66.7% of pTa and pTis, 70.6% of pT1, and 50% of Pt2–4 tumors. Together, the tests correctly identified urothelial cancer in 46 of 47 patients (97.9%). Combined FISH and MAGE RT-PCR testing may offer a promising alternative to conventional urine cytology in screening high-risk populations and in monitoring bladder cancer patients for recurrent tumor. [Copyright &y& Elsevier]
- Published
- 2006
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.