• Physical Therapy Korea
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• v.10 no.1
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• pp.109-128
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• 2003

This study tested whether repeated measurement of median frequency (MDF)-related variables could express the muscle power changes during a 12-week DeLome strengthening program, by using consecutive overlapping FFT (Fast Fourier transformation) and integrated EMG (IEMG) from surface EMG data for isometric and isotonic exercise. To evaluate the effect of training, the following were recorded every 3 weeks for the elbow flexors and knee extensors of 5 healthy male volunteers: MVC, lRM, limb circumference, and surface EMG during isometric MVC or isotonic contraction at 10RM load. From the EMG data, IEMG and variables from a regression analysis between MDF and time were obtained. MVC, lRM, IEMG, and initial MDF increased linearly over the training period. The fatigue index and slope of the regression line increased temporarily until the 6th week and decreased thereafter. From these results, there appeared to be enhanced neural recruitment of fast twitch fibers in the first 6 weeks and continued enhancement in the recruitment and hypertrophy of fast twitch fibers, which led to increased fatigue resistance, over the last 6 weeks. Accordingly, the MDF and IEMG analysis technique could demonstrate the effect of the program detected significant changes in both isometric and isotonic contractions. EMG analysis methods can be used to estimate the electrophysiological and histological changes in skeletal muscles during a strengthening program.

• Advances in environmental research
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• v.6 no.2
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• pp.127-137
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• 2017

Cotton is the major fiber crop in Pakistan that accounts for 2% of total national gross domestic product (GDP). After picking of cotton, the dry stalks are major organic waste that has no fate except burning to cook food in villages. Present research focuses use of cotton stalks as feedstock for biochar production, its characterization and effects on soil characteristics. Dry cotton stalks collected from agricultural field of Bahauddin Zakariya University, Multan, Pakistan were combusted under anaerobic conditions at $450^{\circ}C$. The physicochemical analysis of biochar and cotton stalks show higher values of % total carbon, phosphorus and potassium concentrations in biochar as compared to cotton stalks. The concentration of nitrogen was decreased in biochar. Similarly biochar had greater values of fixed carbon that suggest its role for carbon sequestration and as a soil amendment. The fourier transformation infrared spectroscopic spectra (FTIR) of cotton stalks and biochar exposed more acidic groups in biochar as compared to cotton stalks. The newly developed functional groups in biochar have vital role in increasing surface properties, cation exchange capacity, and water holding capacity, and are responsible for heavy metal remediation in contaminated soil. In a further test, results show increase in the water holding capacity and nutrient retention by a sandy soil amended with biochar. It is concluded that cotton stalks can be effectively used to prepare biochar.

• Bulletin of the Korean Chemical Society
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• v.35 no.7
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• pp.2057-2064
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• 2014

Thermochemical sulfate reduction (TSR) was conducted in autoclave on the system of crude oil and $MgSO_4$ at different temperatures. Gas chromatography pulsed flame photometric detector (GC-PFPD) was used to detected the composition of organic sulfur compounds in oil phase products. The results of the analysis indicate that with increased temperature, the contents of organic sulfur compounds with high molecular weight and thermal stability, such as benzothiophenes and dibenzothiophenes, gradually became dominated. In order to gain greater insight into the formation and distribution of organic sulphur compounds from TSR, positive ion electrospray Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used in detecting the detailed elemental composition and distribution of them. The mass spectra showed that the mass range of sulfur compounds was 200-550 Da. Four sulfur class species, $S_1$, $N_1S_1$, $O_1S_1$ and $O_2S_1$, were assigned in the positive-ion spectrum. Among the identified sulfur compounds, the $S_1$ class species was dominant. The most abundant $S_1$ class species increase associated with the DBE value and carbon number increasing which also indicates the evolution of organic sulfur compounds in TSR is from the labile series to the stable one. In pure blank pyrolysis experiments with crude oil cracking without TSR, different composition and distribution of organic sulfur compounds in oil phase products were seen from mass spectra in order to evaluate their pyrolysis behaviors without $MgSO_4$. FT-IR and XRD were used in analyzing the products of solid phases. Two distinct crystallographic phases MgO and $MgSO_4$ are found to coexist in the products which demonstrated the transformation of inorganic sulfur compounds into organosulfur compounds exist in TSR.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.3
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• pp.126-130
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• 2013

In this study, a shape-stabilized phase change material (SSPCM) was prepared by octadecane and exfoliated graphite nanoplate (xGnP) in a vacuum, to improve thermal storage performance. The octadecane as an organic phase change material (PCM) is very stable against phase separation of PCM, and has the proper temperature range for thermal comfort in the building; and the xGnP is a porous carbon nano-material. Scanning electron microscope (SEM) and Fourier transformation infrared spectrophotometer (FT-IR) were used to confirm the chemical and physical stability of the Ocatadecane/xGnP SSPCM. In addition, thermal properties were determined by Deferential scanning calorimeter (DSC), and Thermogravimetric analysis (TGA). The specific heat of Octadecane/xGnP SSPCM was $14.1J/g{\cdot}K$ at $31.3^{\circ}C$. The melting temperature ranges of melting and freezing were found to be $26{\sim}35^{\circ}C$ and $26{\sim}19^{\circ}C$, respectively. At this time, the latent heats of melting and freezing were 110.9 J/g and 104.5 J/g, respectively. The Octadecane was impregnated into xGnP by as much as about 56.0% of the Octadecane/xGnP SSPCM's mass fraction.

• Physical Therapy Korea
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• v.11 no.2
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• pp.17-25
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• 2004

The purpose of this study was to assess the effect of applied insole types to lower extremities muscle fatigue during treadmill exercise. The control group and each different insole type group consisted of ten healthy male subjects. In the control group and each different insole type (soft type; 10 shore, semi-rigid type; 33 shore, rigid type; 50 shore) treadmill exercise was performed in twenty-five minutes. The electromyography (EMG) signals of four muscle (tibialis anterior, gastrocnemius medialis, rectus femoris, biceps femoris) were recording at sampling rate of 1024 Hz during treadmill exercise. The localized muscle fatigue (LMF) can be investigated using power spectral analysis. When did data analysis that excepted initial five minutes. The raw EMG signals was processed using the fast Fourier Transformation (FFT) and the median power frequency value was determined in initial ten second period and in last ten second period. Fatigue index was calculated and collected data were statistically analyzed by SPSS version 10.0 two-way using analysis of variance (ANOVA) with repeated measures ($4{\times}4$) was used to determine the main effect and interaction. Post hoc was performed with least significant difference. A level of significance was .05. Muscles fatigue index were significantly decreased in insole types (p<.05) and not significantly different in muscle (p>.05). Post hoc analysis shows that fatigue index in soft insole type, semi-rigid insole type and rigid insole type were lower than that control group (p=.028, p=.146, p=.095). There were no interaction between insole type and muscles (p>.05). The finding of this study can be used as a fundamental data when insole is applied and insole can be used to decreased of a fatigue during the dynamic exercise.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.6
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• pp.400-407
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• 2003

In this paper an optical encryption system, which can decrypt the original image by using the autocorrelation terms of a JTC, is proposed. Unlike the classical JTC, the joint input plane of the proposed system is composed in a frequency domain not a spatial domain, thus it needs only one Fourier transformation. To use like this, the phase component appeared in the output plane of JTC should be considered. We presents the effect of phase and provides the solution. An original image is encrypted to a complex-valued random image. The original image is reconstructed using the autocorrelation terms which is the main drawback of JTC, therefore the proposed system is more suitable for JTC and real time processing. By computer simulation and optical experiment, the analysis for the phase effect and the performance of the proposed system are confirmed.

• Journal of the Korean Vacuum Society
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• v.17 no.1
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• pp.46-50
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• 2008

Optical images on the porous silicon exhibiting Febry-Perot fringe pattern have been prepared by using an electrochemical etching of p-type silicon wafer (boron-doped,<100> orientation, resistivity $0.8{\sim}1.2m{\Omega}-cm$) and beam projector. The images remained in the substrate displayed an optical images correlating to the optical pattern and could be useful for optical data storage. A decrease in the effective optical thickness of the Febry-Perot layers was observed, indicative of a change in refractive index induced by exposing of porous silicon to the white light. This provides the ability to fabricate complex optical encoding in the surface of silicon.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.73-78
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• 2010

In this paper, the analysis of the harmonics of distribution power system interconnected with DG(distributed generation) is simulated by using PSCAD/EMTDC and evaluated the harmonics. The modeling system for simulation is similar to the actual distribution system, and solar power system. The simulation analyses are performed at connection points for each sector. Harmonic standards of interconnection with DG (IEEE Std 1547 and IEEE Std 519) are applied to the evaluation algorithm, converted the simulated data through FFT method, evaluated by THD and TDD separately. The harmonic contents in the case of without DG and each sector with DG are evaluated and compared. The results of evaluation showed the effect that the harmonic contents are appropriated at all sector with DG (without DG) in the distribution power systems but the large induction motor(50KW) is increased the harmonic contents.

• The KIPS Transactions:PartA
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• v.13A no.5 s.102
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• pp.429-434
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• 2006

A CCTV system reduces some number of cameras if we use convex-mirror. In this case, convex-mirror Image distorted, we need transformation to flat images. In the center of mirror images, a transformed image has no distortion, but at near boundary image has plentiful distortion. This distortion is caused by occlusion of angled ray and diffraction. We know that the linear filtering approach cannot separate noise from signal where their Fourier spectra overlap. But using a non-linear discretization method, we shall reduce blurred noise. In this paper, we introduce the backward solution of nonlinear wave equation for reducing blurred noise and biased expansion of equilibrium contour. We propose, after applying the introduced method, and calculate with discretization method. To analysis the experimental result, we investigate to PSNR and get about 4dB better than current method.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.2
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• pp.156-164
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• 2003

STS316L had been used as the structural material for energy environmental facilities, because austenite stainless steels like 316L have superior mechanical properties of which toughness, ductility, corrosion resistant and etc. However, those welded structures are receiving severe damage due to increasing of the aged degradation. Most studies until now have been carried out against fatigue behaviors of weldments, and were not well studied on nondestructive evaluation methods. In this study, the fatigue crack propagation behavior of STS316L weldment usually used for vessels of the nuclear power plant was investigated. Also, the degradation characteristics of 316L stainless steel weldments were evaluated by the ultrasonic parameter such as ultrasonic velocity, attenuation factor and time-frequency analysis. The results of this study can be used as a basic data for the prediction of the fatigue crack life of weldments structures without disjointing or stopping service of structures in service.