• Applied Chemistry for Engineering
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• v.30 no.6
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• pp.737-741
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• 2019

A low-cost and flexible potassium ion (K⁺) sensor was fabricated through a screen-printed process. Uniform and conformal coating of conductive inks was verified by scanning electron microscopy and optical microscopy measurements. The K⁺-sensors showed a high sensitivity, fast response time, and low detection limit. The sensitivity of K⁺-sensor was similar to that of both mechanically normal and bent states. The K⁺-sensor exhibited a good reproducibility with no hysteresis effect and excellent long term stability. In addition, the K⁺-sensor showed an excellent selectivity for K⁺ concentrations in the presence of other interfering cation ions. Successful measurements of K⁺ concentrations in sports drink samples were demonstrated by comparing K⁺ concentration values from K⁺-sensor to those of using a commercial K⁺-meter.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.2
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• pp.1-7
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• 1999

The polymide thin films were fabricated by vapor deposition polymerized method of dry processes and studied the electric breakdown characteristics by self healing method. Polyamic-acid(PAA) thin films prepared by vapor deposition-polymerization (VDP) from PMDA(Pyromellitic dianhydride) and DDE(4,4'-diaminodiphenyl ether) were changed to PI thin films by thermal curing. In the same sample, electric breakdown fields increase with increasing test number, and then saturated over test number of the 25th. When the curing temperatures were 200$^{\circ}C$, 250$^{\circ}C$, 300$^{\circ}C$ and 350$^{\circ}C$, the electric breakdown strengths of PI were 1.21MV/cm, 3.94MV/cm, 4.61MV/cm and 4.55MV/cm at the test number of 40th.

• Journal of Periodontal and Implant Science
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• v.30 no.2
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• pp.455-472
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• 2000

Instrumentation for periodontal therapy may induce marginal damage which increases plaque accumulation and result in periodontal disease. But there have not been many reports of instrumentations on the artificial crown so far. Therefore this study is conducted to evaluate the effects of various repeated instrumentations on the porcelain crown marginal portion. Of the 10 extracted periodontally diseased maxillary first premolars, were 12 proximal surface used in this study. The finishing line of the preparation was placed on the root surface below CEJ and then the crown was cast and cemented in usual manner. Every 4 surfaces of the 3 instruments-curet, ultrasonic scaler, and ultrasonic curet- is used. and four samples used in each instruments. The relevant procedures and measurements were repeated 3 times in each surfaces. Marginal gap is measured by the microscope and surface roughness, Scannig Probe Microscope. Measurements are made at 5 points in each surfaces, making 20 points in each instrument. The results evaluated statistically were as follows 1. As instrumentation was repeated, both marginal gap and roughness were increased in all group 2. In the hand curet, marginal gap was increased every instrumentation and roughness was increased after second. 3. In the ultrasonic scaler, both marginal gap and roughness were increased every instrumentation. 4. In the ultrasonic curet, marginal gap was increased after third instrumentation and roughness was increased after second. 5. Marginal gap and roughness used by the ultrasonic curet were lower than the others and no difference was seen between the hand curet and ultrasonic scaler From the results of this study, the ultrasonic curet was useful in some aspect, but careful instrumentation was needed. Furthermore it was important to minimize the instrumentation through complete periodontal therapy before setting and adequate plaque control.

• Journal of the Korea Society of Computer and Information
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• v.12 no.2 s.46
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• pp.123-130
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• 2007

The aim of this study was to propose a fusion and registration method with heterogeneous small animal acquisition system in small animal in-vivo study. After an intravenous injection of $^{18}F$-FDG through tail vain and 60 min delay for uptake, mouse was placed on an acryl plate with fiducial markers that were made for fusion between small animal PET (microPET R4, Concorde Microsystems, Knoxville TN) and Discovery LS CT images. The acquired emission list-mode data was sorted to temporally framed sinograms and reconstructed using FORE rebining and 2D-OSEM algorithms without correction of attenuation and scatter. After PET imaging, CT images were acquired by mean of a clinical PET/CT with high-resolution mode. The microPET and CT images were fusion and co-registered using the fiducial markers and segmented lung region in both data sets to perform a point-based rigid co-registration. This method improves the quantitative accuracy and interpretation of the tracer.

• Applied Chemistry for Engineering
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• v.19 no.4
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• pp.445-451
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• 2008

In order to regenerate the activated carbon polluted by volatile organic compounds (VOCs) using microwave, adsorption and desorption characteristics of benzene over activated carbon (AC) coated with insulating materials were investigated. Physical characteristics of activated carbon and insulator-coated ACs were investigated by means of $N_2$ gas adsorption and scanning electron microscopy (SEM). The amount of VOC adsorbed showed a positive relationship with the specific surface area of the ACs, and spark discharge over insulator-coated ACs did not occur. Potassium silicate (PS) was the best binder for coating of insulating materials on AC. Amount of benzene desorbed by microwave irradiation was dependent on output power of microwave. Nearly same performance was obtained even though the adsorption-desorption operation under microwave irradiation was repeated 5 times. Finally, it was known that the microwave heating was a very effective mean for regenerating the polluted AC.

• The Korean Journal of Nuclear Medicine
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• v.2 no.1
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• pp.15-19
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• 1968

정맥에 주사된 교양(膠樣) 방사성물질은 간(肝)에 있는 Kupffer 세포가 가진 탐식작용에 의해서 혈류로 부터 거의 완전히 제거된다. 이 원리는 정상인(正常入)과 간(肝)경변증환자에서 간(肝)혈류량을 측정하는데 이용된다. 일반적으로 간(肝)경변증때에는 간(肝)에서의 교양물질 추출율이 저하되기 때문에 혈중에서의 제거가 늦어진다하며, Shaldon 등은 혈중제거율측정을 이용하여, 추출율의 저하가 간내(肝內)에서 생기는 동맥과 정맥간의 단락(短絡) 때문에 초래되는 것을 증명하였다. 최근 혈중제거율을 몇가지 간(肝)질환을 진단하는데 이용한 보고가 나왔다. 그러나 그 방법에 대한 상세한 검토가 없었던 것 같다. 저자는 이번 연구에서 손쉽게 얻을 수 있는 교양$^{198}$금(金)을 사용하여 교양물질의 혈중제거율 측정방법을 검토하여 이 검사가 임상에서 통상적(通常的)으로 쓰일 수 있음을 밝혔다. (1) 정상인과 환자가 섞인 52명을 대상으로 동일인에서 $24{\sim}48$ 시간 간격을 두고 반복측정한 혈중제거율치의 오차는 통계학적으로 무시할 수 있었으며, 따라서 이측정은 근소한 오차한계내에서 되풀이할 수 있는 것을 알았다. (2) 정상인 172명에서 얻은 측정치를 토대로 하여 혈중제거율 정상치가 $3.31{\pm}0.73$분임을 알았다(교양 금(金) 입자의 크기에 따라 이 측청치는 달라진다). (3) 조직검사로 진단이 확정된 간(肝)경변증환자 23명을 조사하여 91.3%에서 혈중제거율이 정상한계를 넘어 연장(延長)되는 것을 알았다. 결론으로 혈중제거율검사는 임상에서 손쉽게 실시할 수 있는 간(肝)기능검사가 될 수 있다고 생각되며, 특히 간(肝)경변증을 진단하는데 도움이 된다고 믿는다.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.1 no.2
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• pp.91-93
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• 2008

De Quervain's disease is a stenosing tenosynovitis that affects the synovial sheath of the tendons of the abductor pollicis longus and extensor pollicis brevis; it can be considered a work-related disease, since it frequently is associated with highly repetitive movements in jobs using the hands. The usual sign and symptom of de Quervain's diseases are positive Finkelstein's sign and pain and tenderness around the radial styloid process. The majority of de Quervain's disease has a good results to conservative treatment, but surgery can be performed in case of recurrence or pain last more than 6 months without improvement in spite of conservative treatment. We diagnosed a patient with atypical de Quervain's disease by ultrasonography, treated by local steroid injection and pain was relieved. We report a case of atypical de Quervain's disease evaluated by ultrasonography with brief of literatures.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.19 no.1
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• pp.1-19
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• 1993

Gas chromatography serves to separate the mixtures into its components, and mass spectrometer is used to analyzing of unknown compounds. But there are many problems the identification of horn compounds using by GC only. As this reason GC/MS a very powerful analyzing technique. Mass spectrometer consists of 1) inlet stem 2) ion source 3) Bass filter 4) detectors and 5) data system. There are two analyzing modes in the GC/MS, those are scan and SIM(selected ion mom toping) modes. Scan mode is used when analyzing unknown compounds and SIM mode al lows the mass spectrometer to detect specific compound with very high sensitivity. As GC/MS applications for the analysis of cosmetic products, volatile compounds in lotion, earn foundation and hair color, and carbon distribution of fatty acids in soap were performed. Also as a new sample pre-treatment technique, head space sampler/GC/MS introduced in order to analyze the volatile compounds in a toothpaste.

• Journal of Ocean Engineering and Technology
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• v.26 no.5
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• pp.73-80
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• 2012

It is well known that a considerable amount of scatter is shown in experimental results relating to fatigue crack growth even under identical and constant amplitude cyclic loading conditions. Moreover, flux cored arc welding (FCAW) is a common method used to join thick plates such as the structural members of large scale offshore structures and very large container ships. The objective of this study was to investigate the macro- and microscopic observations of the fatigue crack growth (FCG) behavior of the FCAWed API 2W Gr. 50 steel joints typically applied for offshore structures. In order to clearly understand the randomness of the fatigue crack growth behavior in the materials of three different zones, the weld metal (WM), heat affected zone (HAZ), and base metal (BM), experimental fatigue crack growth tests for each of five specimens were performed on ASTM standard compact tension (CT) specimens under constant amplitude cyclic loading. Special focus was placed on the fatigued fracture surfaces. As a result, a different behavior was observed at the macro-level, depending on the type of material property: BM, HAZ, or WM. The variability in the fatigue crack growth rate for WM was higher than that of BM and HAZ.

• Polymer(Korea)
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• v.29 no.1
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• pp.69-73
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• 2005

To overcome the main disadvantages of non-viral gene delivery systems such as repeated administration due to the low transfection efficiency, poly(D,L-lactide-co-glycolide) was applied to encapsulate pDNA in its microsphere formulation. Free pDNA or various ratios (w/w) of chitosan/pDNA complexes was used for encapsulation, with the resulting encapsulation efficiency of 44%, 5%, and 8% for free pDNA, 0.7:1 and 1:1 ratios, respectively. Scanning electron micrographs of poly(D,L-lactic-co-glycolic acid) (PLGA) microspheres encapsulating pDNA or chitosan-condensed pDNA revealed a smooth spherical shape immediately after microsphere preparation and a collapsed porous shape in 41 days due to the degradation of PLGA. In vitro release profile showed that the 0.7:1 (w/w) ratio formulation exerted 47% release in 26 days, whereas free pDNA or 1:1 (w/w) ratio formulation did only 15% or 32%, respectively.