• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.3
• /
• pp.403-408
• /
• 2008

The gyroscope is the sensor for detecting the rotation in inertial reference frame and constitute the navigation system together an accelerometer. As the inertial reference equipment for attitude determination and control in the satellite, the mechanical gyroscope has been used but it bring the disturbance for mass unbalance so the disturbance give a bad influence to the observation satellite mission because the mechanical gyroscope has the rotation parts. During the launch. The mechanical gyroscope is weak in vibration, shock and has the defect of narrow operating temperature range so it need the special design in integration. Recently the low orbit observation satellite for seeking the high pointing accuracy of image camera payload accept the FOG(Fiber Optic Gyro) or RLG(Ring Laser Gyro) for the attitude determination and control. The Ring Laser Gyro makes use of the Sanac effect within a resonant ring cavity of a He-Ne laser and has more accuracy than the other gyros. It need the 1000V DC to create the He-Ne plasma in discharge tube. In this paper, the design process of the High Voltage Power Supply for RLG(Ring Laser Gyroscope) is described. The specification for High Voltage Power Supply (HVPS) is proposed. Also, The analysis of flyback converter topology is explained. The Design for the HVPS is composed of the inverter circuit, feedback control circuit, high frequency switching transformer design and voltage doubler circuit.

• 한국생물공학회:학술대회논문집
• /
• 2005.04a
• /
• pp.239-243
• /
• 2005

Periosteum-derived progenitor cells (PDPCs) were isolated and characterized by flow cytometric analysis using fluorescence-activated cell sorter (FACS). The chondrogenesis of PDPCs was performed on hyaluronic acid fibers ($Hyalrograft^{\circledR}$) 3D) in chondrogenic induction medium. PDPCs showed the chondrogenic potential when cultured on hyaluronic acid fibers. These results showed that the characterized PDPCs were the chondrogenic progenitor cells and $Hyalrograft^{\circledR}$ 3D served as a useful carrier for PDPCs in transplantation proliferation, matrix synthesis and differentiation. Therefore, it could be used as a matrix for healing the defected cartilage.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2001.05a
• /
• pp.172-175
• /
• 2001

The co-cured Joining method, which is regarded as an adhesively bonded Joining method, is an efficient joining technique because both curing and bonding processes for the composite structures can be achieved simultaneously. It requires neither surface treatment onto the composite adherend nor an additional adhesive joining process because the excess resin, which is extracted from composite materials during consolidation, accomplishes the co-cured Joining process. Since the adhesive of the co-cured joint is the same material as the resin of the composite adherend, the analysis and design of the co-cured joint for composite structures are simpler than those of an adhesively bonded joint, which uses an additional adhesive. In this paper, effects of the manufacturing parameters, namely surface roughness, stacking sequence of the composite adherend, and manufacturing pressure in the autoclave during curing process, on the tensile load bearing capacity of the co-cured single lap joint will be experimentally investigated.

• Composites Research
• /
• v.14 no.1
• /
• pp.47-56
• /
• 2001

In order to enhance high speed stability the composite air spindle system composed of a high modulus carbon fiber composite shaft, powder contained epoxy composite squirrel cage rotor and aluminum tool holder was designed and manufactured. For the optimal design of the composite air spindle system, the stacking sequence and thickness of the composite shaft were selected by considering the fundamental natural frequency and deformation of the system. The analysis gave results that the composite air spindle system had 36% higher natural frequency relative to a conventional air spindle system. The dynamic characteristics of the composite spindle system were compared with those of a conventional steel air spindle system. From the calculated and test results, it was concluded that the composite shaft and the power contained composite rotor were able to enhance the dynamic characteristics of the spindle system effectively due to the low inertia and high speific stiffness of the composite materials.

• Journal of the Korean Society of Costume
• /
• v.50 no.7
• /
• pp.33-46
• /
• 2000

Uniform is the dress of distinctive design or fashion worn by members of a particular group or serving as a means of identification. The postman's uniform of Ministry of Communication should be distinctive or characteristic clothing to provide high functionality and symbolization of job characteristics, cost effectiveness and esthetic. In order to design the postman's new uniform available in 2000, there has been a satisfaction survey to 1,116 postmen. A thorough analysis of survey and informal and face-to-face discussion with postmen give the direction of design concept. One of the most important things in the design concept is to make the uniform high quality & refinement. The style is a refined jumper suit in consideration of form stability, wearing satisfaction, convenience in activity. The basic colors selected are navy and medium gray. The colors of jumper are MOC red ; C.I color Green : a representative color of youth, white : a symbolic color of bright future. All three colors are plaid on a basic nary color. In the selection of the textile, synthetic fiber (Polyester 65%, rayon 35%) equipped with UV cutting as well as water resistance etc. was recommended. In the uniform design process, the effective communication with user (postman) is critical to find the requirements and needs of uniform user (postman). Also. the uniform designer should reflect the above four key factors in design development. Therefore, the uniform should provide the user with high job performance and job pride in wearing the uniform.

• Carbon letters
• /
• v.19
• /
• pp.57-65
• /
• 2016

Isroaniso matrix precursor synthesized from commercially available petroleum pitch was stabilized in air. The influence of oxygen mass gain during stabilization on the yield of matrix precursor was studied. Additionally, the influence of pressure on the yield of the stabilized matrix precursor in a real system was studied. The fourier transform infrared spectrometry (FTIR), thermogravimetric analysis (TGA), yield, yield rate, and yield impact were used to check the effect of stabilization and pressure on the yield of the matrix precursor and the end properties of the composite thereafter. The results showed that the yield increased with stabilization duration up to 20 h whereas it decreased for stabilization duration beyond 20 h. Further results showed that the stabilized matrix precursor for a duration of 5 h could withstand almost two-fold greater hot-pressing pressure without resulting in exudation as compared to that of a 1 h stabilized matrix precursor. The enhanced hot-pressing pressure significantly improved the yield of the matrix precursor. As a consequence, the densification and mechanical properties were increased significantly. Further, the matrix precursor stabilized for a duration of 20 h or more failed to provide proper and uniform binding of the reinforcement.

• Journal of the Korean Ceramic Society
• /
• v.39 no.10
• /
• pp.977-980
• /
• 2002

Using the micro-pulling down method, $Nd_2O_3$ doped crack-free stoichiometric $LiNbO_3$ single crystals were grown in 1 mm diameter and 30∼35 mm length. The homogeneous distributions of $Nd_2O_3$ concentration were confirmed by the electron probe micro analysis. The absorption and photoluminescence spectra were measured with respect to the $Nd_2O_3$ doping.

• Journal of Korean Biological Nursing Science
• /
• v.14 no.1
• /
• pp.16-24
• /
• 2012

Purpose: The purpose of this study was to evaluate the nutritional status of elderly Korean women and to investigate related factors. Methods: A total of 100 elderly women attending a local elderly welfare center were recruited for study. Evaluation criteria included demographics, clinical status, nutritional status (using a mini-nutritional assessment), food intake, and nutritional bioparameters, including homocysteine, transferrin, prealbumin and lymphocyte levels, and their antioxidant power status. Results: Among the test group, 83% of the subjects were classified as undernourished, and they often had hyperlipidemia and a lower intake of fiber ($p$ <.05, respectively) and vegetables than normal subjects. In a correlation analysis, their nutritional status was associated with abdominal circumference, the Korean Geriatric Depression Scale score and the Enriched Social Support Inventory score. Nutritional bioparameters and antioxidant power were associated with age among undernourished subjects. Old age, the prevalence of hyperlipidemia, and poor social support significantly increased the risk of undernutrition. Poor social support, the prevalence of diabetes mellitus and depression significantly increased the risk of nutritional deficiency after controlling for age, educational and economic variables. Conclusion: More strategies to increase social support in the Korean female elderly population may improve their nutritional status.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.13 no.4
• /
• pp.331-341
• /
• 2002

It is expected that the SCM (Subcarrier Multiplexing) optical link system, in which a number of small scale base stations with only antenna and RF transceiver are connected to central station through optical fiber, is in demand. In order to analyze the performance of SCM optical link system fur RF signal transmission, MZ(Mach-Zehnder) modulator's transfer function is modelled as nonlinear form with the cube of input signal. And considering the multiple access interferences occurred In the demodulation of other users'CDMA signals with multipath components after passing through MZ modulator, the BER performance is analyzed.

• BMB Reports
• /
• v.36 no.5
• /
• pp.427-432
• /
• 2003

Jute is the principal coarse fiber for commercial production and use in Bangladesh. Therefore, the development of a high-yielding and environmental-stress tolerant jute variety would be beneficial for the agro economy of Bangladesh. Two molecular fingerprinting techniques, random-amplified polymorphic DNA (RAPD) and amplified-fragment length polymorphism (AFLP) were applied on six jute samples. Two of them were cold-sensitive varieties and the remaining four were cold-tolerant accessions. RAPD and AFLP fingerprints were employed to generate polymorphism between the cold-sensitive varieties and cold-tolerant accessions because of their simplicity, and also because there is no available sequence information on jute. RAPD data were obtained by using 30 arbitrary oligonucleotide primers. Five primers were found to give polymorphism between the varieties that were tested. AFLP fingerprints were generated using 25 combinations of selective-amplification primers. Eight primer combinations gave the best results with 93 polymorphic fragments, and they were able to discriminate the two cold-sensitive and four cold-tolerant jute populations. A cluster analysis, based on the RAPD and AFLP fingerprint data, showed the population-specific grouping of individuals. This information could be useful later in marker-aided selection between the cold-sensitive varieties and cold-tolerant jute accessions.