Y. Min - Profile on Academia.edu (original) (raw)
Papers by Y. Min
Physical Review Letters, 1996
The insulator-metal transition (IMT) for a model quasi-one-dimensional (quasi-1D) conducting poly... more The insulator-metal transition (IMT) for a model quasi-one-dimensional (quasi-1D) conducting polymer (polyaniline) is probed at room temperature (RT) over an unusually broad frequency range (2 meV-6 eV) and also via T-dependent dc conductivity (s dc). We determine that the IMT is not monotonic with increasing s dc ͑RT͒. The RT far infrared scattering time (t) becomes unusually long ($ 10 213 s) as s dc ͑RT͒ increases, even for samples on the insulating side of the IMT. We conclude that the IMT is due to percolation in the presence of inhomogeneous disorder and quasi-1D localization rather than 3D Anderson localization. [S0031-9007(96)01283-5]
Prostaglandins, leukotrienes, and essential fatty acids, 2010
Previous studies suggested that women synthesise docosahexaenoic acid (DHA) more efficiently from... more Previous studies suggested that women synthesise docosahexaenoic acid (DHA) more efficiently from their precursors than men. This study investigated the relationship between diet, platelet phospholipids fatty acids and gender. Dietary intake and platelet phosphatidyl-choline (PC) and phosphatidylethanolamine (PE) fatty acids were determined in Caucasian 40 men and 34 women. Absolute and %energy intakes of arachidonic acid (AA), eicosapentaenoic acid (EPA), and DHA, and the ratios of total n-6/n-3 PUFA and linoleic/alpha-linolenic acids did not differ between the sexes. However, women had higher DHA in PC (1.19 vs 1.05 wt%, p<0.05) and PE (3.62 vs 3.21 wt%, p<0.05) than men. Also EPA (1.10 vs 0.93 wt%, p<0.05) was higher in women's PE. Conversely, men had elevated AA and total n-6 fatty acids in PC. The higher platelet DHA levels and lower platelet AA/EPA and AA/DHA ratios in women of child-bearing age compared with men, may lead to less platelet aggregation and vaso-occ...
Towards optimization of electrical and mechanical properties of polyaniline: Is crosslinking between chains the key?
Synthetic Metals, 1993
ABSTRACT A distinction has been made experimentally between the effect on conductivity and tensil... more ABSTRACT A distinction has been made experimentally between the effect on conductivity and tensile strength caused by 1-D mechanical alignment of parent polyaniline films and the effect produced by the combination of physical crosslinking by crystalline domains and associated 1-D nematic-type alignment of amorphous material. At least in the case of films, a small amount of alignment in amorphous regions results in surprisingly large increases in conductivity and tensile strength; however, extensive crosslinking by crystalline domains and associated 1-D nematic alignment in amorphous regions is necessary in order to optimize interchain electrical and mechanical properties.
Physics Letters A, 2012
For the molecular spintronics transport systems, we propose that the spin current rectifier can b... more For the molecular spintronics transport systems, we propose that the spin current rectifier can be constructed using the nonmagnetic lead. The proposal is confirmed according to the first-principles study of the transport characteristics of a vacuum separating (15, 0) carbon nanotube bundle where only one zigzag edge is hydrogenated. The strong rectification effect for spin (charge) current is obtained in the case of the magnetic parallel (anti-parallel) configuration of two zigzag edges. Our investigations indicate that such device can be used as the spin filter and the counterpart of the p-n junction in the field of molecular electronics.
Physics Letters A, 2008
We perform first-principles calculations of spin-dependent quantum transport in V doped boron nit... more We perform first-principles calculations of spin-dependent quantum transport in V doped boron nitride nanotube: the junction of pristine (6, 0) boron nitride nanotube in contact with V doped (6, 0) boron nitride nanotube electrodes. Large tunnel magnetoresistance and perfect spin filtration effect are obtained. The zero bias tunnel magnetoresistance is found to be several thousand percent, it reduces monotonically to zero with a voltage scale of about 0.65 V, and eventually goes to negative values after the bias of 0.65 V. The ratio of spin injection is above 95% till the bias of 0.85 V and is even as large as 99% for the bias from 0.25 eV to 0.55 eV when the magnetic configurations of two electrodes are parallel. The understanding of the spin-dependent nonequilibrium transport is presented by investigating microscopic details of the transmission coefficients.
A first-principles study of half-metallic ferromagnetism in binary alkaline-earth nitrides with rock-salt structure
Physics Letters A, 2008
ABSTRACT In this Letter, using the first-principles full-potential linearized augmented plane-wav... more ABSTRACT In this Letter, using the first-principles full-potential linearized augmented plane-wave (FP-LAPW) method, we extend the electronic structure and magnetism studies on zinc-blende structure of II V compounds MX (M=Ca,Sr,Ba; X=N,P,As) [M. Sieberer, J. Redinger, S. Khmelevskyi, P. Mohn, Phys. Rev. B 73 (2006) 024404] to the rock-salt structure. It is found that, in the nine rock-salt compounds, only alkaline-earth nitrides CaN, SrN and BaN exhibit ferromagnetic half-metallic character with a magnetic moment of 1.00mu per formula unit. Furthermore, compared with the zinc-blende structure of CaN, SrN and BaN, the rock-salt structure has lower energy, which makes them more promising candidates of possible growth of half-metallic films on suitable substrates.
The potential role for arachidonic and docosahexaenoic acids in protection against some central nervous system injuries in preterm infants
Lipids, 2003
The risk of central nervous, visual, and auditory damage increases from 2/1000 live births in the... more The risk of central nervous, visual, and auditory damage increases from 2/1000 live births in the normal birthweight to > 200/1000 as birthweight falls below 1500 g. Such babies are most likely to be born preterm. Advances in infant care have led to increasing numbers of very-low-birthweight, preterm infants surviving to school age with moderate to severe brain damage. Steroids are one of the current treatments, but they cause significant, long-term problems. The evidence reported here suggests an additional approach to protecting the very preterm infant by supporting neurovascular membrane integrity. The complications of preterm, very-low-birthweight babies include bronchopulmonary dysplasia, retinopathy of prematurity, intraventricular hemorrhage, periventricular leukomalacia, and necrotizing enterocolitis, all of which have a vascular component. Arachidonic acid (AA) and DHA are essential, structural, and functional constituents of cell membranes. They are especially required for the growth and function of the brain and vascular systems, which are the primary biofocus of human fetal growth. Molecular dynamics and experimental evidence suggest that DHA could be the ligand for the retinoid X receptor (RXR) in neural tissue. RXR activation is an obligatory step in signaling to the nucleus and in the regulation of gene expression. Very preterm babies are born with minimal fat stores and suboptimal circulating levels of these nutrients. Postnatally, they lose the biomagnification of the proportions of AA and DHA by the placenta for the fetus. No current nutritional management repairs these deficits. The placental biomagnification profile highlights AA rather than DHA. The resultant fetal FA profile closely resembles that of the vascular endothelium and not the brain. Without this nourishment, cell membrane abnormalities would be predicted. We present a scientific rationale for a common pathogenic process in the complications of prematurity.
Ferromagnetic properties, electronic structure, and formation energy of Ga[sub 0.9375]M[sub 0.0625]N (M=vacancy, Ca) by first principles study
Journal of Applied Physics, 2008
Using the full potential linearized augmented plane wave method based on the spin density functio... more Using the full potential linearized augmented plane wave method based on the spin density functional theory, we investigate the ferromagnetic properties, the electronic structure, and the formation energy of Ga0.9375M0.0625N (M=vacancy, Ca). The calculations indicate that both cases prefer ferromagnetic ground state. The magnetic moments mainly come from the N atoms surrounding the defect centers, which are different from the conventional diluted magnetic semiconductor. High formation energy for the Ga vacancy suggests that the defect concentration is too low to result in the ferromagnetic GaN. The formation energy for the two substitutional (CaGa,CaN) and two interstitial sites (tetrahedral T, Cai−T and octahedral O, Cai−O) doped configurations indicates that Ca prefers the substitutional Ga in GaN. The defect concentrations for the Ga0.9375Ca0.0625N under thermal equilibrium N-rich and N-realistic growth conditions are also discussed, respectively. The calculations show that defect concentration under N-rich condition can readily reach 7%, while under N-realistic growth condition, the maximum defect concentration is as low as 1.71% when the growth temperature increases to 1100 K (melting point of GaN). These results suggest that it would be a little difficult to achieve ferromagnetic state for Ga0.9375Ca0.0625N using the chemical-equilibrium fabrication method, such as chemical precipitation. Using the same method as that for Cu-doped ZnO [L. H. Ye &etal;, Phys. Rev. B 73, 033203 (2006)], the transition temperature of Ga0.9375Ca0.0625N may be close to room temperature.
Pregnancy Reduces Arachidonic and Docosahexaenoic in Plasma Triacylglycerols of Korean Women
International Journal for Vitamin and Nutrition Research, 2000
Plasma triacylglycerol (TG) fatty acid composition of healthy non-pregnant and non-lactating wome... more Plasma triacylglycerol (TG) fatty acid composition of healthy non-pregnant and non-lactating women, expectant mothers and their term neonates from Seoul, South Korea was investigated. They were ethnically homogeneous and the women had comparable age and parity. Blood samples were obtained at recruitment, third trimester and birth from the non-pregnant women, expectant mothers and neonates respectively. Percent levels of linoleic and arachidonic acids and n-6 metabolites and total n-6 were significantly lower in the pregnant women than in the non-pregnant (p < 0.0001). Similarly, there were lower levels of alpha-linolenic (p = 0.033), eicosapentaenoic and docosahexaenoic acids and n-3 metabolites and total n-3 (p < 0.0001) in the expectant mothers. Compared with their mothers, the neonates had higher proportions of dihomo-gamma-linolenic, arachidonic, docosatetraenoic and docosapentaenoic acids and n-6 metabolites (p < 0.0001) and lower linoleic acid (p < 0.0001). Of the n-3 series, alpha-linolenic acid was lower (p < 0.0001) and eicosapentaenoic, docosapentaenoic and docosahexaenoic acids and n-3 metabolites and total n-3 higher (p < 0.0001) in the neonates compared with their mothers. The study reveals that pregnancy is associated with a reduction in the relative levels of plasma triacylglycerol arachidonic and docosahexaenoic acids. Moreover, it indicates that the decline is a manifestation of selective transfer of these fatty acids to the developing fetus.
Physical Review Letters, 1997
The temperature (T ) dependent dc conductivity (s DC ) (down to 20 mK) and dielectric function at... more The temperature (T ) dependent dc conductivity (s DC ) (down to 20 mK) and dielectric function at optical frequencies (0.002 -6 eV) and 6.5 GHz are used to probe the inhomogeneous disorder-driven insulator-metal transition in conducting polymers. A correlation between large low T s DC and the presence to low T of a small fraction of the carrier density delocalized with long transport times (.10 213 s) indicates that metallic s DC is due to only a small fraction of the charge carriers. The achievable s DC for these systems when the entire charge carrier density participates is estimated to surpass that of copper. [S0031-9007(97)03024-X]
Physical Review Letters, 1996
The insulator-metal transition (IMT) for a model quasi-one-dimensional (quasi-1D) conducting poly... more The insulator-metal transition (IMT) for a model quasi-one-dimensional (quasi-1D) conducting polymer (polyaniline) is probed at room temperature (RT) over an unusually broad frequency range (2 meV-6 eV) and also via T-dependent dc conductivity (s dc). We determine that the IMT is not monotonic with increasing s dc ͑RT͒. The RT far infrared scattering time (t) becomes unusually long ($ 10 213 s) as s dc ͑RT͒ increases, even for samples on the insulating side of the IMT. We conclude that the IMT is due to percolation in the presence of inhomogeneous disorder and quasi-1D localization rather than 3D Anderson localization. [S0031-9007(96)01283-5]
Prostaglandins, leukotrienes, and essential fatty acids, 2010
Previous studies suggested that women synthesise docosahexaenoic acid (DHA) more efficiently from... more Previous studies suggested that women synthesise docosahexaenoic acid (DHA) more efficiently from their precursors than men. This study investigated the relationship between diet, platelet phospholipids fatty acids and gender. Dietary intake and platelet phosphatidyl-choline (PC) and phosphatidylethanolamine (PE) fatty acids were determined in Caucasian 40 men and 34 women. Absolute and %energy intakes of arachidonic acid (AA), eicosapentaenoic acid (EPA), and DHA, and the ratios of total n-6/n-3 PUFA and linoleic/alpha-linolenic acids did not differ between the sexes. However, women had higher DHA in PC (1.19 vs 1.05 wt%, p<0.05) and PE (3.62 vs 3.21 wt%, p<0.05) than men. Also EPA (1.10 vs 0.93 wt%, p<0.05) was higher in women's PE. Conversely, men had elevated AA and total n-6 fatty acids in PC. The higher platelet DHA levels and lower platelet AA/EPA and AA/DHA ratios in women of child-bearing age compared with men, may lead to less platelet aggregation and vaso-occ...
Towards optimization of electrical and mechanical properties of polyaniline: Is crosslinking between chains the key?
Synthetic Metals, 1993
ABSTRACT A distinction has been made experimentally between the effect on conductivity and tensil... more ABSTRACT A distinction has been made experimentally between the effect on conductivity and tensile strength caused by 1-D mechanical alignment of parent polyaniline films and the effect produced by the combination of physical crosslinking by crystalline domains and associated 1-D nematic-type alignment of amorphous material. At least in the case of films, a small amount of alignment in amorphous regions results in surprisingly large increases in conductivity and tensile strength; however, extensive crosslinking by crystalline domains and associated 1-D nematic alignment in amorphous regions is necessary in order to optimize interchain electrical and mechanical properties.
Physics Letters A, 2012
For the molecular spintronics transport systems, we propose that the spin current rectifier can b... more For the molecular spintronics transport systems, we propose that the spin current rectifier can be constructed using the nonmagnetic lead. The proposal is confirmed according to the first-principles study of the transport characteristics of a vacuum separating (15, 0) carbon nanotube bundle where only one zigzag edge is hydrogenated. The strong rectification effect for spin (charge) current is obtained in the case of the magnetic parallel (anti-parallel) configuration of two zigzag edges. Our investigations indicate that such device can be used as the spin filter and the counterpart of the p-n junction in the field of molecular electronics.
Physics Letters A, 2008
We perform first-principles calculations of spin-dependent quantum transport in V doped boron nit... more We perform first-principles calculations of spin-dependent quantum transport in V doped boron nitride nanotube: the junction of pristine (6, 0) boron nitride nanotube in contact with V doped (6, 0) boron nitride nanotube electrodes. Large tunnel magnetoresistance and perfect spin filtration effect are obtained. The zero bias tunnel magnetoresistance is found to be several thousand percent, it reduces monotonically to zero with a voltage scale of about 0.65 V, and eventually goes to negative values after the bias of 0.65 V. The ratio of spin injection is above 95% till the bias of 0.85 V and is even as large as 99% for the bias from 0.25 eV to 0.55 eV when the magnetic configurations of two electrodes are parallel. The understanding of the spin-dependent nonequilibrium transport is presented by investigating microscopic details of the transmission coefficients.
A first-principles study of half-metallic ferromagnetism in binary alkaline-earth nitrides with rock-salt structure
Physics Letters A, 2008
ABSTRACT In this Letter, using the first-principles full-potential linearized augmented plane-wav... more ABSTRACT In this Letter, using the first-principles full-potential linearized augmented plane-wave (FP-LAPW) method, we extend the electronic structure and magnetism studies on zinc-blende structure of II V compounds MX (M=Ca,Sr,Ba; X=N,P,As) [M. Sieberer, J. Redinger, S. Khmelevskyi, P. Mohn, Phys. Rev. B 73 (2006) 024404] to the rock-salt structure. It is found that, in the nine rock-salt compounds, only alkaline-earth nitrides CaN, SrN and BaN exhibit ferromagnetic half-metallic character with a magnetic moment of 1.00mu per formula unit. Furthermore, compared with the zinc-blende structure of CaN, SrN and BaN, the rock-salt structure has lower energy, which makes them more promising candidates of possible growth of half-metallic films on suitable substrates.
The potential role for arachidonic and docosahexaenoic acids in protection against some central nervous system injuries in preterm infants
Lipids, 2003
The risk of central nervous, visual, and auditory damage increases from 2/1000 live births in the... more The risk of central nervous, visual, and auditory damage increases from 2/1000 live births in the normal birthweight to > 200/1000 as birthweight falls below 1500 g. Such babies are most likely to be born preterm. Advances in infant care have led to increasing numbers of very-low-birthweight, preterm infants surviving to school age with moderate to severe brain damage. Steroids are one of the current treatments, but they cause significant, long-term problems. The evidence reported here suggests an additional approach to protecting the very preterm infant by supporting neurovascular membrane integrity. The complications of preterm, very-low-birthweight babies include bronchopulmonary dysplasia, retinopathy of prematurity, intraventricular hemorrhage, periventricular leukomalacia, and necrotizing enterocolitis, all of which have a vascular component. Arachidonic acid (AA) and DHA are essential, structural, and functional constituents of cell membranes. They are especially required for the growth and function of the brain and vascular systems, which are the primary biofocus of human fetal growth. Molecular dynamics and experimental evidence suggest that DHA could be the ligand for the retinoid X receptor (RXR) in neural tissue. RXR activation is an obligatory step in signaling to the nucleus and in the regulation of gene expression. Very preterm babies are born with minimal fat stores and suboptimal circulating levels of these nutrients. Postnatally, they lose the biomagnification of the proportions of AA and DHA by the placenta for the fetus. No current nutritional management repairs these deficits. The placental biomagnification profile highlights AA rather than DHA. The resultant fetal FA profile closely resembles that of the vascular endothelium and not the brain. Without this nourishment, cell membrane abnormalities would be predicted. We present a scientific rationale for a common pathogenic process in the complications of prematurity.
Ferromagnetic properties, electronic structure, and formation energy of Ga[sub 0.9375]M[sub 0.0625]N (M=vacancy, Ca) by first principles study
Journal of Applied Physics, 2008
Using the full potential linearized augmented plane wave method based on the spin density functio... more Using the full potential linearized augmented plane wave method based on the spin density functional theory, we investigate the ferromagnetic properties, the electronic structure, and the formation energy of Ga0.9375M0.0625N (M=vacancy, Ca). The calculations indicate that both cases prefer ferromagnetic ground state. The magnetic moments mainly come from the N atoms surrounding the defect centers, which are different from the conventional diluted magnetic semiconductor. High formation energy for the Ga vacancy suggests that the defect concentration is too low to result in the ferromagnetic GaN. The formation energy for the two substitutional (CaGa,CaN) and two interstitial sites (tetrahedral T, Cai−T and octahedral O, Cai−O) doped configurations indicates that Ca prefers the substitutional Ga in GaN. The defect concentrations for the Ga0.9375Ca0.0625N under thermal equilibrium N-rich and N-realistic growth conditions are also discussed, respectively. The calculations show that defect concentration under N-rich condition can readily reach 7%, while under N-realistic growth condition, the maximum defect concentration is as low as 1.71% when the growth temperature increases to 1100 K (melting point of GaN). These results suggest that it would be a little difficult to achieve ferromagnetic state for Ga0.9375Ca0.0625N using the chemical-equilibrium fabrication method, such as chemical precipitation. Using the same method as that for Cu-doped ZnO [L. H. Ye &etal;, Phys. Rev. B 73, 033203 (2006)], the transition temperature of Ga0.9375Ca0.0625N may be close to room temperature.
Pregnancy Reduces Arachidonic and Docosahexaenoic in Plasma Triacylglycerols of Korean Women
International Journal for Vitamin and Nutrition Research, 2000
Plasma triacylglycerol (TG) fatty acid composition of healthy non-pregnant and non-lactating wome... more Plasma triacylglycerol (TG) fatty acid composition of healthy non-pregnant and non-lactating women, expectant mothers and their term neonates from Seoul, South Korea was investigated. They were ethnically homogeneous and the women had comparable age and parity. Blood samples were obtained at recruitment, third trimester and birth from the non-pregnant women, expectant mothers and neonates respectively. Percent levels of linoleic and arachidonic acids and n-6 metabolites and total n-6 were significantly lower in the pregnant women than in the non-pregnant (p < 0.0001). Similarly, there were lower levels of alpha-linolenic (p = 0.033), eicosapentaenoic and docosahexaenoic acids and n-3 metabolites and total n-3 (p < 0.0001) in the expectant mothers. Compared with their mothers, the neonates had higher proportions of dihomo-gamma-linolenic, arachidonic, docosatetraenoic and docosapentaenoic acids and n-6 metabolites (p < 0.0001) and lower linoleic acid (p < 0.0001). Of the n-3 series, alpha-linolenic acid was lower (p < 0.0001) and eicosapentaenoic, docosapentaenoic and docosahexaenoic acids and n-3 metabolites and total n-3 higher (p < 0.0001) in the neonates compared with their mothers. The study reveals that pregnancy is associated with a reduction in the relative levels of plasma triacylglycerol arachidonic and docosahexaenoic acids. Moreover, it indicates that the decline is a manifestation of selective transfer of these fatty acids to the developing fetus.
Physical Review Letters, 1997
The temperature (T ) dependent dc conductivity (s DC ) (down to 20 mK) and dielectric function at... more The temperature (T ) dependent dc conductivity (s DC ) (down to 20 mK) and dielectric function at optical frequencies (0.002 -6 eV) and 6.5 GHz are used to probe the inhomogeneous disorder-driven insulator-metal transition in conducting polymers. A correlation between large low T s DC and the presence to low T of a small fraction of the carrier density delocalized with long transport times (.10 213 s) indicates that metallic s DC is due to only a small fraction of the charge carriers. The achievable s DC for these systems when the entire charge carrier density participates is estimated to surpass that of copper. [S0031-9007(97)03024-X]