• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.4
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• pp.359-364
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• 2000

The paper describes the electron transport characteristics in SP$_{6}$+He gas calculated E/N values 0.1~700[Td] by the Monte Carlos simulation and Boltzmann equation method using a set of electron collision cross sections determined by the authors and the values of electron swarm parameters obtained by TOF method. This study gained the values of the electron swarm parameters such as the electron drift velocity the electron ionization or attachment coefficients longitudinal and transverse diffusion coefficients for SF$_{6}$+He gas at a range of E/N.E/N.

• Applied Microscopy
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• v.26 no.1
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• pp.47-57
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• 1996

This study analysed the transport properties of bladder mucosa known as the typical system of 'tight epithelia' by using TEM observation with both rapid freeze-fracture electron microscopy and thin-section method and mainly analysed the cellular characteristics of turtle bladder epithelial cells. The bladder epithelium, like other tight epithelia, consists of a heterogenous population of cells. The majority of the mucosal cells are the granular cells and may function primarily in the process of active $Na^+$ reabsorption in turtle bladder. The remaining two types of cells are rich in mitochondria and is believed to be res-ponsible for a single major transport system, namely, $H^+$ transport by A-type of cell and urinary $HCO_{3}^-$ secretion by B-type of cell. As viewed in freeze-fracture electron micrograph, the tight junctions form a continuous tight seal around the epithelial cells, thus restricting diffusion in tight epithelia. In addition, the apical surface membranes have a population of rod-shaped intramembranous particles (IMPs). It is believed that these IMPs probably represent the components of the proton pump. However, it is likely that these characteristics of the apical transporter remain to be clarified in tight epithelial cells.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.159-162
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• 1998

This paper describes the electron transport characteristics in $SF_6$+He gas calculated for range of E/N values from 50~700[Td] by the Monte Carlo simulation and Boltzrnann equation method using a set of electmn collision cross sections determined by the authors and the values of electron swarm parameters are obtained by M F method. The results gained that the values of the electron swarm parameters such as the electron drift velocity, the electron ionization or attachment coefficents, longitudinal and h-ansverse diffusion coefficients agree with the experimental and theoretical for a range of E/N.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.5
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• pp.338-343
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• 2015

Dye sensitized solar cells (DSSCs), which is one of the contending renewable energy sources, have the problem of low efficiency. To improve the efficiency, the fast electron transport and long electron lifetime are required. In this study, one-dimensional sodium hexatitanate, which is expected to have an advantageous structure for electron transports, was synthesized and the feasibility of the material on DSSC was tested. Its physical properties were characterized by the SEM, XRD, and BET method. The dye adsorption and solar cell properties were also characterized. In addition to the expectation of fast electron transport, sodium hexatitanate showed longer electron lifetime: This means sodium hexatitanate can improve the DSSC efficiency. However, it showed low current and voltage because of the low surface area leading to the low amount of dye adsorbed. Therefore, it should be mixed with titanium oxide with high surface area for the optimal performance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.696-699
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• 1999

The electron transport coefficients in $SF_6+N_2$ gas is analysed in range of E/N values from 100~900(Td) by a Monte Carlo simulation and Boltzmann method, using a set of electron collision cross sections determined by the authors. The result of the Monte Carlo simulation such as electron drift velocity, ionization and electron attachment coefficients, longitudinal and transverse diffusion coefficients in nearly agreement with the respective experimental and theoretical for a range of E/N.

• Korean Journal of Materials Research
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• v.26 no.1
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• pp.35-41
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• 2016

The electrical transport properties of $La_{0.5}Sr_{0.5}CrO_3$ below room temperatures were investigated by dielectric, dc resistivity, magnetic properties and thermoelectric power. Below $T_c$, $La_{0.5}Sr_{0.5}CrO_3$ contains a dielectric relaxation process in the tangent loss and electric modulus. The $La_{0.5}Sr_{0.5}CrO_3$ involves the transition from high temperature thermal activated conduction process to low temperature one. The transition temperature corresponds well to the Curie point. The relaxation mechanism has been discussed in the frame of electric modulus spectra. The scaling behavior of the modulus suggests that the relaxation mechanism describes the same mechanism at various temperatures. The low temperature conduction and relaxation takes place in the ferromagnetic phase. The ferromagnetic state in $La_{0.5}Sr_{0.5}CrO_3$ indicates that the electron - magnon interaction occurs, and drives the carriers towards localization in tandem with the electron - lattice interaction even at temperature above the Curie temperature.

• Journal of Plant Biology
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• v.34 no.3
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• pp.215-221
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• 1991

Photoxynthetic properties of polyvinylalcohol (PVA)-immobilized chloroplast especially regarded to stability of photosynthetic electron transport and the fluorescence induction pattern were studied. When isolated spinach chloroplasts were immobilized with PVA, it showed good preservation of photosynthetic electron transport activity, especially PS II activity, during storage at -15$^{\circ}C$, 4$^{\circ}C$ and 2$0^{\circ}C$. And immobilized chloroplasts revealed similar thermostability of whole chain electron transport to free chloroplsts. And the absorption peak of red band of chloroplasts showed the blue-shift of 2-4 nm after immobilization. Fv/Fm ratio of chlorophyll fluorescence slightly decreased after immobilization. White light pulse after continuous light do not induced the additional fluorescence rise. This means chlorophyll fluorescence at room temperature reached to Fmax under continuous light in the immobilized chloroplasts. It seems that PVA may be a good candidate for immobilization matrix for the preservation of photosynthetic function of thylakoids and for the continuous use of chloroplast membranes of higher plants for solar energy storage and conversion.

• Applied Science and Convergence Technology
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• v.23 no.3
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• pp.128-133
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• 2014

We study the ballistic spin transport properties in a two-dimensional electron gas system in the presence of magnetic barriers using a transfer matrix method. We concentrate on the size-effect of the magnetic barriers parallel to a two-dimensional electron gas plane. We calculate the transmission probability of the ballistic spin transport in the magnetic barrier structure while varying the width of the magnetic barriers. It is shown that resonant tunneling oscillation is affected by the width and height of the magnetic barriers sensitively as well as by the inter-spacing of the barriers. We also consider the effect of additional electrostatic modulation on the top of the magnetic barriers, which could enhance the current spin polarization. Because all-semiconductor-based devices are free from the resistance mismatch problem, a resonant tunneling structure using the two-dimensional electron gas system with electric-magnetic modulation would play an important role in future spintronics applications. From the results here, we provide information on the physical parameters of a device to produce well-defined spin-polarized current.

• Transactions on Electrical and Electronic Materials
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• v.8 no.6
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• pp.250-254
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• 2007

Applying the moving photo-carrier grating(MPG) technique and time-of-flight(TOF) measurements, we studied the transport properties of stabilized amorphous selenium typical of the material used in direct conversion X-ray imaging devices. For MPG measurement, we obtained electron and hole mobility and the recombination lifetime of $\alpha-Se$ films with arsenic(As) additions. We found an apparent increase in hole drift mobility and recombination lifetime, especially when 0.3 % As was added into $\alpha-Se$ film, whereas electron mobility decreased with the addition of As due to the defect density. For TOF measurement, a laser beam with pulse duration of 5 ns and wavelength of 350 nm was illuminated on the surface of $\alpha-Se$ with a thickness of 400 ${\mu}m$. The measured hole and electron transit times were about 8.73 ${\mu}s$ and 229.17 ${\mu}s$, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.501-504
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• 2001

We used time-of-flight method to analyze transport properties of charge carrier which is produced by X-ray exposure. It is the research of charge transport and specific property of trap that is performed in direct digital x-ray image receptor. But the results shows us different measurement value of electron and charge drift mobility and it is difficult to precise analysis about charge transport properties and trap mechanism. We measured transit time and drift mobility of charge carriers using time-of-flight method to evaluate the correlation of a-Se thickness change and electric field. We made a testing glass with a-Se of 400 ${\mu}m$ thickness on coming glass using thermoevaporation method and built Au electrode with 300nm, $2{\varphi}$ on both sides of a-Se, As a result of this experiment, electron and hole transit time was each $229.17{\mu}s$ and $8.73{\mu}s$ at $10V/{\mu}m$ electric field and Drift mobility was each $0.00174 cm^{2}/V{\cdot}s$, $0.04584cm^{2}/V{\cdot}s$.