• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.365-366
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• 2002

The sliding wear behavior of ultra high molecular weight polyethylene (UHMWPE) was examined on a novel low temperature degradation-free zirconia/alumina composite material and conventional alumina and zirconia ceramics used for femoral head in total hip joint replacement. The wear of UHMWPE pins against these ceramic disks was evaluated by performing linear reciprocal sliding and repeat pass rotational sliding tests for one million cycles in bovine serum. The weight loss of polyethylene against the novel low temperature degradation-free zirconia/alumina composite disks was much less than those against conventional ceramics for all tests. The mean weight loss of the polyethylene pins was more io the linear reciprocal sliding test than in the repeal pass rotational sliding lest for all kinds of disk materials. Neither the coherent transfer film nor the surface damage was observed on the surface of the novel zirconia/alumina composite disks during the test. The observed r,'stilts indicated that the wear of the polyethylene was closely related to contacting materials and kinematic motions. In conclusion, the novel zirconia/alumina composite leads the least wear of polyethylene among the tested ceramics and demonstrates the potential as lhe alternative materials for femoral head in total hip joint replacement.

• ETRI Journal
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• v.44 no.3
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• pp.491-503
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• 2022

Metal-oxide-semiconductor field-effect transistors (MOSFETs) are continuously scaling down in the nanoscale region to improve the functionality of integrated circuits. The scaling down of MOSFET devices causes short-channel effects in the nanoscale region. In nanoscale region, leakage current components are increasing, resulting in substantial power dissipation. Very large-scale integration designers are constantly exploring different effective methods of mitigating the power dissipation. In this study, a transistor-level input-controlled stacking (ICS) approach is proposed for minimizing significant power dissipation. A low-power ICS approach is extensively discussed to verify its importance in low-power applications. Circuit reliability is monitored for process and voltage and temperature variations. The ICS approach is designed and simulated using Cadence's tools and compared with existing low-power and high-speed techniques at a 22-nm technology node. The ICS approach decreases power dissipation by 84.95% at a cost of 5.89 times increase in propagation delay, and improves energy dissipation reliability by 82.54% compared with conventional circuit for a ring oscillator comprising 5-inverters.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.175-176
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• 2018

We have developed liquis precursotr delivery system (LDS) for ultra thin film preparation in semiconductor devices. The LDS concists of 3 major parts : aerosol generator, vaporizer and vapor storage. By uaing LDS which was attached to plasma enhanced chemical vapor deposition system, thin Al2O3 layer was prepared at extremely low temperature and characterized.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1080-1082
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• 2008

An ultra-thin reflective flexible LCD film has been demonstrated. The 30% thickness of the display can be reduced by applying a quarter-wave-plate film as upper substrate. A low temperature alignment material and special designed photo spacer were applied in this new display. The bending behavior was improved by reduced thickness.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.267-269
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• 1997

The electrical properties due to the Benzotriazole(following as BTA) additive in fluids for insulating and cooling the ultra-high voltage transformer is studied in this paper. Specimen having the several contents of BTA, such as 5[ppm]. 10[ppm] and 30[ppm] is used in order to investigate the characteristics on volume resistivity in case of fluid flow in experimental device made in lab. Volume resistivity is decreased with an increase of fluid flow velocity and increased with BTA content in low temperature region, but volume resistivity of specimen contained BTA 10[ppm] is the largest thing over $30[^{\circ}C]{\sim}50[^{\circ}C]$ than the others in experiment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.465-468
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• 1999

Electrical properties of metal-ferroelectric-semiconductor field effect transistor(MFSFET) using $BaMgF_4$ thin films grown on p-Si(100) substrates have been investigated. $BaMgF_4$ thin films have been directly deposited on the p-Si(100) wafers at a low temperature of $300^{\circ}C$ in an ultra high vacuum(UHV) system. First an in-situ post-deposition annealing was conducted for 20s at $650^{\circ}C$ and second an in-situ post-annealing was conducted for 10s at $950^{\circ}C$. The electrical properties of MFSFET compared with using A1 and Pt electrodes.

• Proceedings of the Korean Magnestics Society Conference
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• 2013.05a
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• pp.15-16
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• 2013

Magnetization behavior of ultra thin $Fe_xCo_{1-x}$ alloy (where x varies from 0 to 100) has been investigated as functions of composition on Cr (100) substrate by using in situ surface magneto optical Kerr effect (SMOKE). It's always show in plane uniaxial magnetic anisotropy at room temperature (RT) & Low temperature (LT). It is observed that composition dependent coercive force maximum at about 30 at % Co and 70 at % Co atomic ratio and minimum near equiatomic site. The relative magnetic moments as composition variation also show magnetization collapse near equiatomic site. The magnetization behaviors of Fe-Co alloy on Cr (100) due to composition varies are supported the order-disordering as well as structural stability bcc (ferromagnetic)/fcc (anti-ferromagnetic) phase stability magnetism.

• Structural Engineering and Mechanics
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• v.91 no.2
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• pp.177-195
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• 2024

This research plans to investigate the simultaneous impact of bamboo fibers (BF) and steel fibers (SF) on the mechanical and spalling characteristics of ultra-high-performance concrete (UHPC) exposed to high temperatures (HT). To this aim, 25 mixtures were made and assessed. BF was added at five contents of 0, 2.5, 5, 7.5 and 10 kg/m³. Additionally, SF was used at five weight contents: 0%, 1%, 2%, 3% and 4%. Specimens were exposed to temperatures ranging between 25℃ and 800℃. Thus, com-pressive, tensile, and flexural strengths, elastic moduli, mass loss, and permeability were measured. Experiments revealed that the simultaneous use of low BF and SF contents could totally prevent spalling of UHPC, but the use of either SF or BF alone could not prevent spalling at high levels of fibers. Besides, the synergetic positive impact of BF and SF on the spalling resistance of UHPC was by reason of the rise of BF' permeability and the bridging role of SF at HT. Moreover, it was concluded that the use of SF could moderate the adverse influence of BF on the compressive resistance of UHPC.

• Journal of electromagnetic engineering and science
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• v.9 no.3
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• pp.164-173
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• 2009

In this paper, two new circuit structures for European and U.S. ultra-wide band(UWB) bandpass filters(BPFs) with sharp roll-off characteristics are introduced. We show first that the ultra-wide bandpass property is obtained from a $\lambda$/4 open T resonator with a capacitively coupled $\lambda$/4 short-circuited line, which provides two attenuation poles at lower and upper cutoff frequencies. Then, two identical capacitively coupled input/output lines, which can be $\lambda$/4-length open ends or $\lambda$/2-length short ends, with the T-resonator, are adopted to suppress lower and higher frequency components outside of the pass band. There is coupling between the input and output lines providing two additional transmission zeros in the lower and upper transition bands of the filter. Since the coupling between the T-resonator with the $\lambda$/4 short-circuited line and the input/output lines limits the bandwidth of the filter to the European UWB band, both the $\lambda$/4 short-circuited line and the input/output lines are inserted between the two stacked T-resonators for the U.S. UWB band. The filter structures are simulated with ADS and HFSS and realized with low-temperature co-fired ceramic(LTCC) green tape which has the dielectric constant of 7.8. Measurement results agree well with HFSS simulation results.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.6
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• pp.286-292
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• 2005

Terahertz wave is a kind of electromagnetic radiation whose frequency lies in 0.1THz $\~$10THz range. In this paper, generation and detection characteristics of terahertz (THz) radiation by photoconductive antenna (PCA) method has been described. Using modern integrated circuit techniques, micron-sized dipole antenna has been fabricated on a low-temperature grown GaAs (LT-GaAs) wafer. A mode-locked Ti:Sapphire femtosecond laser beam is guided and focused onto photoconductive antennas (emitter and detector) to generate and measure THz pulses. Ultra-wide band THz radiation with frequencies between 0.1 THz and 3 THz was observed. Terahertz field amplitude variation with antenna bias voltage, pump laser power, pump laser wavelength and probe laser power was investigated. As a primary application example. a live clover leaf was imaged with the terahertz radiation.