• Applied Microscopy
• /
• v.41 no.2
• /
• pp.81-88
• /
• 2011

Even though importance of nano-scale structure and compositional analysis have been getting increased, existing analysis tools have been reached to their limitations. Recent development of Atom Probe Tomography (APT), providing 3-dimensional elemental distribution and compositional information with sub-nm scale special resolution and tens of ppm detection limit, is one of key technique which can overcome these limitations. However, due to the fact that APT is not well known yet in the domestic research area, it has been rarely utilized so far. Therefore, in this article, the theoretical background of APT was briefly introduced with sample preparation to help understanding APT analysis.

• Journal of Practical Engineering Education
• /
• v.14 no.2
• /
• pp.327-332
• /
• 2022

This experiment presents a precise analysis method using a mass spectrometer in the biopharmaceutical market, where utility is expanding. Among various techniques for analyzing the protein drug, somatotropin, the peptide fragments through biochemical sample preparation was analyzed by LC-MS/MS characterization. The analysis process was performed by separation analysis using nanoUPLC and MS/MS analysis using Orbitrap. In the case of somatotropin with 21 tryptic peptides, 13 of them were consistent with theoretical predictions within an average of 1 ppm error.

• Analytical Science and Technology
• /
• v.7 no.4
• /
• pp.435-440
• /
• 1994

Qualitative and quantitative analysis for the anionic surfactants used in the metal washing fluid (brand names are BFA and BCA) was performed by the capillary electrophoresis. Acetonitrile and sodium benzoate were mixed with the buffer solution which controlled at pH 10. Under the 18kV applied voltage, the electropherograms have shown the theoretical plates more than $10^4$. Determined as the concentration at the S/N~3, the typical detection limit was ~5 ppm and the calibration curves have shown the correlation coefficients higher than ~0.99. Based on these results, it was concluded that each components were octanoate, decanoate, dodecanoate, tetradecanoate, hexadecanoate and the relative ratio was 1.0 : 1.0 : 6.5 : 2.1 : 0.8 for the BFA.

• Korean Journal of Materials Research
• /
• v.9 no.9
• /
• pp.943-947
• /
• 1999

The crystal structure and the microwave dielectric properties of $La(Mg_{1/2}Ti_{1/2})O_3$ ceramics have been investigated. $La(Mg_{1/2}Ti_{1/2})O_3$ has the 1:1 ordered monoclinic structure with the lattice parameters of $a = 5.5467(3){\AA}, b = 5.5616(3){\AA}, c = 7.8426(5) {\AA} and \beta = 89.9589 (2)^{\circ}$ The spacegroup of LMT is $P2_1/n$. Monoclinic LMT has the in­phase and anti-phase tilting of octahedra with the $a^_a^_c^_$ tilting system. Anti-parallel shift of A-site cations was also found in LMT. The relative density of the specimens sintered above $1600^{\circ}C$ was ranged between 95 % and 96 % of the theoretical density and the dielectric constant of specimens was about 28. The highest $Q\timesf$ achieved in this investigation was 63,100 for the specimen sintered at $1630^{\circ}C$ for 5 hr. Temperature coefficient of resonance frequency ranged from $>-74 ppm/^{\circ}C ~ -79 ppm/^{\circ}C$.

• Journal of Sensor Science and Technology
• /
• v.7 no.2
• /
• pp.111-116
• /
• 1998

The simple solid electrolyte carbon dioxide sensor with heaters were fabricated by using Li ionic conductor. Two Au electrodes were used for the reference and sensing electrode respectively. Two types of gas sensors, type ( I ) and type (II), were fabricated. Type ( I ) sensor was fabricated by the method of melting and crystallizing alkali metal carbonate at the temperature of $420{\sim}500^{\circ}C$. The sensing membrane of type (II) sensor was formed by the printing method on sensing electrode after metal carbonate was mixed with binder. The response characteristics of sensors fabricated for the carbon dioxide were investigated for a range of $CO_{2}$ concentration from 950 ppm to 9,950 ppm at operating temperature $420^{\circ}C$. Type ( I ) sensor and type (II) sensor showed the sensitivity of 62 mV/decade and 65 mV/decade respectively. The emf/decade of type (II) sensor tested at $420^{\circ}C$ almost followed the theoretical value of Nernst's equation and showed stable response characteristics with the fast response time of $15{\sim}20$ sec. Also type (II) sensor showed excellent stability and reproduction properties for 60 days.

• Journal of Internet of Things and Convergence
• /
• v.9 no.1
• /
• pp.105-115
• /
• 2023

This study seeks to find a way to induce users to expand their direct participation in sports through the acceptance of digital technology. From July 1 to August 30, 2022, a survey was conducted targeting home training users who applied the Internet of Things (IoT). 129 people participated in the survey through non-face-to-face self-administration method. For data processing, frequency analysis, exploratory factor analysis, reliability analysis, correlation analysis, multiple regression analysis, and 3-step mediation regression analysis were conducted using IBM's SPSS 21.0 program. The results of the study are as follows. First, in the relationship between the home training PPM model and direct participation in sports, ease appeared to have a mediating effect. In the factors of push, simple functionality showed a complete mediating effect, and inefficiency showed a partial mediating effect. Among pull factors, enjoyment and possibility of experience showed a complete mediating effect. In the mooring factors, individual innovativeness showed a complete mediating effect. Second, in the relationship between home training PPM model and direct participation in sports, usefulness showed a mediating effect. In the factors of push, simple functionality showed a complete mediating effect, and inefficiency showed a partial mediating effect. Among pull factors, enjoyment and possibility of experience showed a complete mediating effect. Among the mooring factors, individual innovativeness showed a partial mediating effect. Through this research, it is expected that the sports industry will contribute to the expansion of consumption expenditure and economic growth through the expansion of digital technologies such as NFT, Metaverse, and virtual/augmented reality.

• The Journal of the Petrological Society of Korea
• /
• v.10 no.3
• /
• pp.179-189
• /
• 2001

The determination of trace concentration of U, Th and Pb was carried out for chemical dating of zircon and monazite by electron microprobe. Detection limit and error range should be considered to measure characteristic X-rays of M-line from those minerals, which are low in the ionization of atom and low peak intensity in the spectrum. The element of U, Th and Pb were simultaneously measured with 3 spectrometers equipped with PET crystal to reduce a total counting time and error due to drift of instrumental operating condition. Detection limit could be improved from increase of the peak/background ratio through adjusting pulse height analyzer about 1000 mv baseline. Under permissible maximum analytical conditions, theoretical detection limit of U, Th and Pb is down to 30 ppm (99% confidence level). The analytical result was maintained at a relative error $\pm$10% ($2{\sigma}$) in 800 ppm Pb, $\pm$5% ($2{\sigma}$) in 2330 ppm U and $\pm$10% ($2{\sigma}$) in dating from a single measurement of zircon at 15 keV and 100 nA. However, for the precise dating of zircon and monazite, if it is considered a 3 $\mu\textrm{m}$ spatial resolution, <100 ppm ($3{\sigma}$) detection limit and <$\pm$10% ($2{\sigma}$) relative error, optimum analytical conditions are given as 15~20 keV accelerating voltage, 100~200 nA beam current and 300~1200 sec total counting time. To reduce material damage by high current, there is need to be up to 3~5 $\mu\textrm{m}$ of electron beam diameter, or to use arithmetic average of multiple measuring at a shorter counting time. A younger or relatively low concentration rocks can be dated chemically by lower detection limit and improved precision resulted from increase of current and measuring time.

• Parasites, Hosts and Diseases
• /
• v.32 no.1
• /
• pp.13-18
• /
• 1994

Chronic Clonorchis sinensis (CS) infection Is etiologically related to cholangiocarcinoma (CHCA) in human and animals. This study was carried out to clarify the role of CS Infection on dimethylnitrosamine (DMN)-induced cholanglocarcinogenesis. Fifteen hamsters were administered with 15 ppm DMN for 4 weeks and one week later, the hamsters were infected with 15 metacercariae of CS (DMN→CS group). The other 15 hamsters were infected with CS and after 5 weeks they were treated with the drug, praziquantel. Again one week later, the hamsters were administered with DMN (CS→DMN group). The other IS hamsters were adulnistered with DMN and CS simultaneously (CS + DMN group) . Histopathological examination of the livers showed CHCA with papillary or adenomatous hyperplasia of bile ductules in 3 of 15 hamsters of DMN→CS group and in 11 of 15 hamsters of DMN + CS group. These results suggest that CS infection to hamsters may have a promoting effect on the development of CHCA.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.13 no.3
• /
• pp.11-15
• /
• 1976

한국산 천연수정은 보석장식용으로서는 그 품질이 이미 알려져 있으나 수정진동자로서의 특성에 관해서는 아직 보고된 바가 없다. 본 연구는 특히 경상도일대에서 채굴되고 있는 천연수정을 채집, 선별, 가공하여 그 수정진동자로서의 사용가능성을 실험을 통하여 검토한 것이다. 필자들은 채굴현장 근처에서 채집한 원석을 특별히 고안제작된 검사경을 이용하여 분석선별하였으며 X-ray를 사용하여 AT-cut로 orientation 한후 시판을 절단하였다. 다음 적용하여 전기적, 광학적 쌍수상태를 검토하고 다시 선별하였다 Dimensioning은 5MHz를 목표로 하였는데 연잠제를 사용하여 5MHz의 조도까지 연마하고 전극으로서 표준형의 은막을 부착하여 시판을 완성하였다. 시판을 대한 측정결과는 모든 등가정수가 대표적인 수입수정판의 것과 대등하였으며 특히 Q는 모두 105를 넘었다. 온도특성도 AT-cut의 이론치와 대차가 없었으며 -20℃-+100℃ 범위에서 최대 20PPM 이내의 편차를 보였다. 즉, 한국산 천연수정은 적절히 선별, 가공 한다면 부유한 수정진동자의 원재로서 사용할수 있음이 증명되었다. Samples of domestic natural quartz were collected and screened optically and chemically, and, after weeding out portions unfit for electrical resonator, were cut into AT-cut wafers, which in turn were dimensioned, trimmed and lapped into 5MHz resonator units. The results of measurements obtained from the specimens indicated excellent electrical characteristics of domestic natural quartz with the average Q quotient of 10s or higher. Temperature characteristics also showed typical AT-cut corves with the frequency deviation of 20PPM at maximum throughout the range of -20 to 100℃. The experiment on the initial batch of samples amply indicates the excellent electrical quality of domestic natural quartz as quartz resonator units.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2001.05a
• /
• pp.333-336
• /
• 2001

The transient response in PDFA(Praseodymium-Doped Fiber Amplifier) is theoretically investigated. The PDFA has the spectral gain band in 1.3${\mu}{\textrm}{m}$. The transient model includes the transient buildup of the population inversion, the pump power, and the signal power and their transient variation along the fiber amplifier. The numerical analysis of transient model can predict the gain saturation, the variation of pump power and the gain as a function of the fiber length. It also shows the gain saturation and recovery effects depending on the pumping rate lead to distortion and saturation in the amplification of optical pulse. The results of numerical analysis, for the case of the Pr ion concentration of 1000ppm and the pump power of 0.5W the gain saturation is obtained 30dB at the length of 5m and the saturation time of upper level is 250 $mutextrm{s}$.