• JSTS:Journal of Semiconductor Technology and Science
• /
• v.5 no.3
• /
• pp.182-186
• /
• 2005

In this work, thermal evaporation system was employed to deposit thin films of SiC on glass substrates in order to determine the parameters of them. Measurements included transmission, absorption, Seebak effect, resistivity and conductivity, absorption coefficient, type of energy band-gap, extinction coefficient as functions of photon energy and the effect of increasing film thickness on transmittance. Results explained that SiC thin film is an n-type semiconductor of indirect energy band-gap of ${\sim}3eV$, cut-off wavelength of 448nm, absorption coefficient of $3.4395{\times}10^{4}cm^{-1}$ and extinction coefficient of 0.154. The experimental measured values are in good agreement with the typical values of SiC thin films prepared by other advanced deposition techniques.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2019.05a
• /
• pp.107-108
• /
• 2019

The interlayer noise of the apartment house is a typical problem that reduces the quality of the residential environment. Therefore, many researchers have developed soundproofing materials that blocks noise between floors. However, most development technologies do not have the noise cut-off effect felt by residents, and may also have a defect in long-term deflection. In this respect, this study developed high-performance interlayer soundproofing material that can overcome existing problems. The developed technology has the noise reduction effect experienced by the residents and it has high durability without long-term deflection. Therefore, high-performance interlayer soundproofing material is expected to contribute to reducing disputes over noise between floors of apartment residents.

• Journal of Life Science
• /
• v.10 no.2
• /
• pp.131-139
• /
• 2000

Lecithin-free egg yolk protein (EYP), the by-product of lecithin extraction from egg yolk, which is denatured with an organic solvent, would normally be discarded. In this study, the denatured protein was renatured with alkali, and hydrolyzed with Alcalase in order to utilize by-product. The hydrolysate was separated through a series of ultrafiltration membranes with molecular weight cut-off (MWOO) of 10, 5 and 1 kDa, and the antioxidative activities of the hydrolysates was investigated. The 5K hydrolysate, permeate from 5 kDa membrane, showed stronger antioxidative activity than 10 K and 1 K hydrolysate which were permeated from 10 kDa and 1 kDa membrane, in a linoleic acid autoxidation system. In addition, the optimum concentration of antioxidative activity for 5 K hydrolysate was 1%, and the activity was about 37% higher as compared with α-tocopherol. The synergistic effect was also increased by using the hydrolysates with α-tocopherol.

• Analytical Science and Technology
• /
• v.15 no.1
• /
• pp.7-14
• /
• 2002

Laser ablation ion trap mass spectrometry (LAITMS) was developed for the analysis of metal and ceramic samples. For this study, XeCl excimer laser (308 nm) was used for ablating the samples and ITMS was used as a detector. Samples were introduced from outside of a ring electrode and this way of sample introduction was very effective for solid samples when laser ablation was employed. Helium gas was used as a buffer gas, and its effect on sensitivity and some parameters (buffer gas pressure, ion storage time, and cut-off RF voltage) were studied. The optimized conditions were $1{\times}10^{-4}$ Torr of buffer gas pressure, 100 ms of ion storage time and $1150V_{p-p}$ of cut-off RF voltage. From that results, copper (Cu) and molybdenum (Mo) metals were tested with LAITMS and the mass spectra of these pure metals were compared with the natural abundance of isotope ratio. We also examined ceramic samples ($Al_2O_3$, $ZrO_2$) and represented the result of elemental analysis.

• Clinical and Experimental Reproductive Medicine
• /
• v.41 no.2
• /
• pp.75-79
• /
• 2014

Objective: To study the effect of body composition on reproduction in women with unexplained infertility treated with a controlled ovarian hyperstimulation and intrauterine insemination programme. Methods: This prospective observational study was conducted on 308 unexplained infertile women who were scheduled for a controlled ovarian hyperstimulation and intrauterine insemination programme and were grouped as pregnant and non-pregnant. Anthropometric measurements were performed using TANITA-420MA before the treatment cycle. Body composition was determined using a bioelectrical impedance analysis system. Results: Body fat mass was significantly lower in pregnant women than in non-pregnant women ($15.61{\pm}3.65$ vs. $18.78{\pm}5.97$, respectively) (p=0.01). In a multiple regression analysis, body fat mass proved to have a stronger association with fecundity than the percentage of body fat, body mass index, or the waist/hip ratio (standardized regression coefficient${\geq}0.277$, t-value ${\geq}2.537$; p<0.05). The cut-off value of fat mass, which was evaluated using the receiver operating characteristics curve, was 16.65 with a sensitivity of 61.8% and a specificity of 70.2%. Below this cut-off value, the odds of the pregnancy occurrence was found to be 2.5 times more likely. Conclusion: Body fat mass can be predictive for pregnancy in patients with unexplained infertility scheduled for a controlled ovarian hyperstimulation and intrauterine insemination programme.

• Journal of Acupuncture Research
• /
• v.24 no.1
• /
• pp.151-163
• /
• 2007

Objectives : Juglandis Semen herbal acupuncture solution(JSS) has a broad array of clinical applications in oriental medicine, including treatment of chronic musculoskeletal diseases such as arthritis. This study was performed to investigate the global gene expression profiles using microarray assay in RAW 264.7 cell line treated with JSS and to advance our understanding of the pharmacologic effect of JSS. Methods : Change of the gene expression profile in RAW cell line following treatment with lipopolysaccharide(LPS) alone, or with LPS plus JSS was investigated with a cut-off level of 2 fold change in the expression. Especially, Change of the gene expression by treatment with LPS alone was compared with that by treatment with LPS plus JSS with a cut-off level of 1/2 fold change in the expression. Results: Of the 8170 genes profiled in this study, 51 were upragulated and 21 downregulated following LPS treatment, and 88 were upregulated and 69 downregulated following costimulation of JSS and LPS. Of the 51 genes upregulated following LPS treatment, 10 were downregulated following costimulation of JSS and LPS. Of the 21 genes downregulated following LPS treatment, 3 were upregulated following costimulation of JSS and LPS. Conclusion : JSS treatment induced upregulation of some genes including IL-10 and downregulation of that including MMP13 with its possible implication in an antiinflammatory action of JSS. However, further research on expression profile changes induced by JSS treatment is expected.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.13 no.1
• /
• pp.67-76
• /
• 1989

Although the standard 2-CR network filter, one of the filters used for measuring surface roughness, is being used widely in the field of industry it possesses a weak point of causing Phase-distortion when the wavelength is passing through. Phase-corrected filter is used for eliminating these phase-distortion and the difference of phase characteristics between these two filters is thought to have considerable amount of effect on the surface roughness value. Moveover, the definition on this is as yet unclear. Therefore, the Rt and Rz value, obtained when the wavelength are passed through the standard and phase-corrected filters from the same random machine-processed surface, and its standard deviation are compared and experimented in this paper. Also, the ratio of relative bearing curve complying to the phase characteristics of these two filters are acquired. As a result, the use of phese-corrected filter is appropriate in experiments where the form of wavelength is important, and the standard deviation on the same experimented values appeared greater with when using the standard filter. The rate of relative bearing curve became greater as .lambda.$_{c}$, the cut-off value of filter, became smaller.r.

• Journal of the Korean Data and Information Science Society
• /
• v.27 no.1
• /
• pp.131-142
• /
• 2016

Outliers in surveys can have a large effect on estimates of totals. This is especially true in business surveys where the populations are drawn are typically skewed. In this paper, we discussed the practical development and implementation of methods to identify and deal with outliers. A detection method is based on quartile method and detected outlier is processed in various ways. The study examines two versions of winsorised estimators with three different cut-off thresholds for each one. For the simulation study, four types of weight transformation function have been considered.

• Smart Structures and Systems
• /
• v.23 no.2
• /
• pp.141-153
• /
• 2019

This research deals with wave propagation of the functionally graded (FG) nano-beams based on the nonlocal elasticity theory considering surface and flexoelectric effects. The FG nano-beam is resting in Winkler-Pasternak foundation. It is assumed that the material properties of the nano-beam changes continuously along the thickness direction according to simple power-law form. In order to include coupling of strain gradients and electrical polarizations in governing equations of motion, the nonlocal non-classical nano-beam model containg flexoelectric effect is used. Also, the effects of surface elasticity, dielectricity and piezoelectricity as well as bulk flexoelectricity are all taken into consideration. The governing equations of motion are derived using Hamilton principle based on first shear deformation beam theory (FSDBT) and also considering residual surface stresses. The analytical method is used to calculate phase velocity of wave propagation in FG nano-beam as well as cut-off frequency. After verification with validated reference, comprehensive numerical results are presented to investigate the influence of important parameters such as flexoelectric coefficients of the surface, bulk and residual surface stresses, Winkler and shear coefficients of foundation, power gradient index of FG material, and geometric dimensions on the wave propagation characteristics of FG nano-beam. The numerical results indicate that considering surface effects/flexoelectric property caused phase velocity increases/decreases in low wave number range, respectively. The influences of aforementioned parameters on the occurrence cut-off frequency point are very small.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.26 no.3
• /
• pp.262-272
• /
• 2023

A polymer-based mechanical low-pass filter(m-LPF) for high-g accelerometers makes it possible to remove high-frequency transient noises from acceleration signals, thus ensuring repeatable and reliable measurement on high-g acceleration. We establish a prediction model for performance of m-LPF by combining a fundamental vibration model with the fractional derivative standard linear solid(FD SLS) model describing the storage modulus and loss modulus of polymers. Here, the FD SLS model is modified to consider the effect of m-LPF shape factor (i.e., thickness) on storage modulus and loss modulus. The prediction accuracy is verified by comparing the displacement transmissibility(or cut-off frequency) estimated using our model with that measured from 3 kinds of polymers(polysulfide rubber(PSR), silicone rubber(SR), and polydimethylsiloxane(PDMS)). Our findings will contribute a significant growth of m-LPF for high-g accelerometers.