• Journal of the Korean Ceramic Society
• /
• v.49 no.6
• /
• pp.620-624
• /
• 2012

The role of moisture remaining inside the deposition chamber during the formation of the cubic boron nitride (c-BN) phase in BN film was investigated. BN films were deposited by an unbalanced magnetron sputtering (UBM) method. Single-crystal (001) Si wafers were used as substrates. A hexagonal boron nitride (h-BN) target was used as a sputter target which was connected to a 13.56 MHz radiofrequency electric power source at 400 W. The substrate was biased at -60 V using a 200 kHz high-frequency power supply. The deposition pressure was 0.27 Pa with a flow of Ar 18 sccm - $N_2$ 2 sccm mixed gas. The inside of the deposition chamber was maintained at a moisture level of 65% during the initial stage. The effects of the evacuation time, duration time of heating the substrate holder at $250^{\circ}C$ as well as the plasma treatment on the inside chamber wall on the formation of c-BN were studied. The effects of heating as well as the plasma treatment very effectively eliminated the moisture adsorbed on the chamber wall. A pre-deposition condition for the stable and repeatable deposition of c-BN is suggested.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.11a
• /
• pp.869-872
• /
• 2011

Ignition tests of an oxidizer rich preburner for a staged combustion cycle liquid rocket engine were performed to evaluate combustion performance. Design operation conditions of the tested oxidizer rich preburner are about 60 of OF ratio and 20 MPa of combustion pressure. The entire kerosene and some LOx injected into the mixing head is burned in combustion chamber and the remaining LOx injected through center holes of combustion chamber is vaporized. Full flow ignition method with hypergolic fuel was used. Each propellant was supplied in two stages for soft ignition. Test results, low frequency oscillation was occurred in low flow rate conditions under 45% of design flow rate. Stable ignition in the course of design combustion pressure was able to induce by minimization of low flow rate ignition region to escape low frequency oscillation.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.4
• /
• pp.1587-1590
• /
• 2015

Background: Chronic lymphoid leukemia (CLL) is the most frequent type of adult leukemia. The Rai and Binet staging systems have been well recognized as standards for assessing the treatment requirements and overall survival in CLL patients. However, there is a need to seek newer prognostic markers to identify stable or progressive forms of CLL that will facilitate risk-adapted treatment strategies. Currently a molecular biomarker ZAP-70 has attracted interest as providing prognostic information in CLL patients. Objective: To determine the frequency of ZAP-70 positivity in B-CLL patients at disease presentation. Materials and Methods: From January 2011 to September 2014, 89 patients were diagnosed to have chronic lymphoid leukemia. Complete blood count was done on an automated analyzer (Cell Dyne, Abott Architect, USA), while immunophenotyping was conducted for each patient to establish the diagnosis of the disease. ZAP-70 expression was evaluated by flow cytometry. Data were compiled and analyzed by SPSS version 21. Results: Out of the total of 89 B-CLL patients, 62 (69.7%) were male and 27 (30.3%) were females with a male to female ratio of 2:1. The mean age was $57.5{\pm}12.1years$. The frequency of ZAP-70 positivity in our B-CLL patients was found to be 13.5%. ZAP-70 positivity was significantly correlated with stage III disease and high absolute lymphocytic count (P<0.05). No correlation of ZAP-70 could be established with age and gender (p>0.05). Conclusions: The frequency of ZAP-70 in our patients appears low. It is approximately half that in international data. We would recommend to screen all the newly diagnosed patients with CLL for ZAP-70 protein expression for risk stratification, family counseling and to predict overall survival.

• Journal of Biomedical Engineering Research
• /
• v.28 no.5
• /
• pp.647-656
• /
• 2007

The purpose of this study was to analyze the effects of vibratory stimulus as somatosensory inputs on the postural control in human standing. To study these effects, the center of pressure(COP) was observed while subjects were standing on a stable and an unstable support with co-stimulated mechanical vibrations to flexor ankle muscles(tibialis anterior tendon, achilles tendon) and two plantar zones on both foot. The COP sway measurement was repeated twice in four conditions: (1) with visual cue and vibration, (2) without visual cue and vibration, (3) with visual cue and without vibration, (4) without visual cue and with vibration. The calculated parameters were the COP sway area and the distance, the median frequency and the spectral energy of COP sway in three intervals $0.1{\sim}0.3,\;0.3{\sim}1,\;1{\sim}3Hz$. The results showed that vibratory stimulus affect postural stability. The reduction rate of the COP sway with vibratory stimulus were higher on the unstable support because the effect of postural stability increases when afferent nervous flow is more activated by vibration on unstable support. If unclear visual or vibratory information is received, one type of information is compared with the other type of sensory information. Then the input balance between visual and vibratory information is corrected to maintain postural stability. These findings are important for the rehabilitation system of postural balance control and the use of vibratory information.

• Ocean and Polar Research
• /
• v.35 no.3
• /
• pp.219-228
• /
• 2013

In Korea, more than 300 oil spill accidents occur every year. Despite the frequency, only a small pool of data is available on the initial effect of oil spill on macrobenthic fauna inhabiting rocky shores. The aim of this study was to analyze the variation of macrobenthic fauna composition and community structure on rocky shores, and understand the impact of oil on rocky shore organisms after the Hebei Spirit oil spill. Field surveys were carried out in five regions dose to the wreck site in January, April and September 2008. Polluted sites after the Hebei Spirit oil spill showed that biological index consistently decreased for 9 months limited to breeding and recruitment of organisms by spilled oil. Macrobenthic community was subdivided into 3 groups by species elimination and differences between density of major dominant species: enriched biota community under a relatively stable environment, the second with relatively low ecological index and the last with poor community. In this study, species number did not clearly reflect the effect of oil on the rare and mobile species. However, mean density, biomass and community structure showed the effect of oil by considering breeding activity, decline in recruitment and variation pattern with time.

• Proceedings of the Korean Society for Applied Microbiology Conference
• /
• 2000.04a
• /
• pp.178-181
• /
• 2000

In order to develop the novel gene expression system, we introduced new control elements which could influence the foreign gene expression in animal cells. When the foreign genes are introduced into the genome of higher eukaryotic cells, the expressions from these integrated genes are often low and can vary greatly depending on the positions of the integration sites due to the complex nature of the chromatin structures (1). First we screened the various DNA sequence elements which can function as an insulator of gene expression from these position effects and can cooperate with the SV40 enhancer/promoter. Among the several DNA elements from the various sources, we identified the particular DNA element which confers the increased frequency of the positive colonies, assayed by the reporter gene from stable selections indicating significantly reduced position effects. This element also showed the several fold-increased expression level as well as the copy-number dependent expression with host cell specificity. Second we modified the transcription termination element where we introduced the specific terminator in combination with SV40 polyA signal. This modified terminator showed the increased efficiency and the level of the gene expression. By combining these two elements, we made the animal cell expression system and tested successfully for the recombinant protein productions of TGF ${\beta}$-soluble receptor, Antithrombin III, and single chain Pro-Urokinase. [Supported by grants from MOCIE]

• Journal of the Korea Institute of Military Science and Technology
• /
• v.22 no.1
• /
• pp.60-71
• /
• 2019

Electrical power supply is needed to operate the radar system in the field. In addition, it should not cause performance deterioration under the environmental factors due to characteristics of military equipment, and should not cause malfunction due to electromagnetic waves generated in radar, and then should not cause malfunction in radar equipment. Therefore, By applying a permanent magnet to the rotor of the generator, light weighting and high efficiency of generator were achieved. As a result, electrical performance test of the generator, the rated output power was 80.8 kW, the maximum output power was 88.1 kW, and the output power efficiency was 98.1 % under the full load condition. When the load capacity of the generator was changed from no load to full load, the maximum voltage variation was 3.6 % and the frequency variation was 0.3 %. As a result of the transient response test for measuring the output power of the generator according to the load characteristics change, the maximum voltage variation of 7.9 %, frequency variation of 0.5 % were confirmed, and the transient response time was 2.1 seconds. Environmental tests were conducted in accordance with MIL-STD-810G and MIL-STD-461F to evaluate the operability of the generator groups. Normal operation of radar system generator group was confirmed under high temperature and low temperature environment conditions. Electromagnetic tests were conducted to check if electromagnetic wave generated from both radar system and generator group in operation caused any performance deterioration to each other. As a result, it was confirmed that the performance deterioration due to electromagnetic wave inflow, radiation, and conduction did not occur. It is expected that it should be possible to provide high efficiency power supply and stable power supply by applying to various military system as well as radar system.

• 한국체육학회지인문사회과학편
• /
• v.58 no.6
• /
• pp.449-459
• /
• 2019

The purpose of this study is to identify how postural mechanics affects postural control on balance and stability by using frequency analysis technique from the kinematic data acquired during the one leg standing posture. For this purpose, the experimental group consisted of two groups, the normal group (n=6) and the national Gymnastics group (n=6). Displacement data of CoP were analyzed by frequency analysis of rambling (RM) and trembling (TR) by FFT signal processing. As a results, there was a significant difference in evaluating the stabilization index between the two groups with the eyes open and closed one leg stnading (p <.05). The cause of the difference was found to be the output of the maximum amplitude of RM (f1) and TR (f2) (p <.05). In particular, in the low frequency RM of 8-9 Hz, which is a natural frequency of signal wave involved in postural feedback feedback, the main frequency appeared to be performs the exercise mechanism of stable brain posture control. And in the high frequency TM of 120-135 Hz, it is considered that the adaptation of the reflective muscle response is minimized to minimize posture shaking. In conclusion, this study provides evidence for the intrinsic main frequencies according to the postural control ability which affects the CNS in one leg standing.

• Journal of the Korea Safety Management & Science
• /
• v.6 no.1
• /
• pp.125-133
• /
• 2004

Greeting the globalization and information period of 21C, the improvement of the distributional system structure and modernization of publishing distribution are the seriously required periodic assignments for the publishing industry that is a national knowledge and culture industry to be equipped with the core competitiveness. First, it is to found a large distributional organization that is able to provide total logistics services in time that is essential to the publishing company and bookstore. Second, it is to have a logistics service to act up to the variable requirements of customers such as publishing companies and bookstores under the rapidly changing distribution environment. Third, it is to provide the standardized information of publishing distribution. It is needed to establish a total distributional center in collaboration to satisfy the requirements of publishing industry as above. By doing this work, structure of the publishing distribution system can be improved and its constitution can be strengthen, and it is possible not only to construct a stable supply system but also to realize an information-based system in the publishing industry with the construction of information system and its utilization. Furthermore, the application of RFID in the publishing distribution is essentially required to provide the symbolic model and logistics infrastructure into the 'Paju publishing culture information industrial complex'. It could be possible by growing the international recognition regarding distribution environment and strengthening the international competitiveness in the period of the ""Open door".

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
• /
• v.12 no.3
• /
• pp.2-11
• /
• 2001

The L-shaped strip is shown to be an attractive feed for the thick mierostrip antenna (thickness around 10% of the operating wavelength). The L-strip incorporated with the radiating patch introduces a capacitance suppressing some of the inductance introduced by the strip itself. In this paper, a wideband microstrip patch antenna fed by L-strip for the PCS ($1,750{\sim}1,850MHz$) and IMT-2000 ($1,920{\sim}2,170MHz$) broad-band is presented. A two-element array fed by L-strip is also proposed. Both the antennas have stable radiation patterns across the passband. The impedance bandwidth is over 31% (VSWR < 1.5, 615 MHz) of the center frequency. Moreover, both the antennas have about 7 dBi average gain.