• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.129-132
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• 2008

The generally six-port phase correlator is comprised of a wilkinson power divider and three $90^{\circ}$ hybrid coupler, got bandwidth performance of less than 10%. in this paper, the six-port phase correlator using two section power divider has 33% bandwidth and external matching hybrid coupler has 15% bandwidth was designed with the center frequency of 2.5GHz. Analysis of the simulation result indicates that RF port and LO port got frequency bandwidth of 13%. Insert loss performance of fabricated six-port phase correlator is incremented, but bandwidth resembles simulation result. And phase tolerance within bandwidth is less than $90^{\circ}$.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.11
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• pp.1390-1398
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• 1999

A numerical analysis for ROT sparger of PWR(Pressurized Water Reactor) is carried out. Computation is performed to investigate the flow characteristics as the change of design factor. As the result of this study, RDT sparger's flow resistance coefficient is K=3.53 at the present design condition if engineering mar&in is considered with 20%, and flow ratio into branch pipe is $Q_s/Q_i=0.41$. Velocity distribution at exit is not uniform because of separation in branch pipe. In the change of inlet flow rate and section area ratio of branch pipe for main pipe, flow resistance coefficient is increased as $Q_s/Q_i$ decreasing, but in the change of branch angle and outlet nozzle diameter of main pipe, flow resistance coefficient is decreased as $Q_s/Q_i$ decreasing. As the change rate of $Q_s/Q_i$ is the larger, the change rate of flow resistance coefficient is the larger. The change rate of pressure loss is the largest change as section area ratio changing. The optimal design condition of sparger is estimated as the outlet nozzle diameter ratio of main pipe is $D_s/D_i=0.333$, the section area ratio is $A_s/A_i=0.2$ and the branch angle is ${\alpha}=55^{\circ}$.

• The Journal of Korean Medical History
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• v.33 no.1
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• pp.1-9
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• 2020

Pubescent Angelica is generally used in musculoskeletal diseases of lower extremity, itching, external contraction (外感) and furuncle, with the effect of dispelling wind, draining dampness, dispersing the external (解表) and stopping pain. The disease parts of Treasured Mirror of Eastern Medicine (東醫寶鑑) contain 121 examples of the usage of Pubescent Angelica. Cases of musculoskeletal diseases and itching are mainly in the External Bodily Elements section (外形篇), and those of external contraction and furuncle are mainly in the Miscellaneous Disorder section (雜病篇). Internal Bodily Elements section (內景篇) has 10 prescriptions that involve Pubescent Angelica, in Dreams (2), Voice (1), Uterus (4), Parasites (1), and Feces (2) chapters. Their specific symptoms are insomnia and sleep paralysis (Dreams), loss of voice due to external contraction (Voice), uterine hemorrhage (Uterus), phthisis (Parasites), and constipation and diarrhea (Feces). It is not easy for students beginning their clinical training to link the effects of Pubescent Angelica and its actual usage, especially in the area of internal medicine. By Analyzing the whole cases of Pubescent Angelica in the Treasured Mirror, we found various usages out of reach of basic knowledge of the herb. Such method can be utilized not only in developing herbal knowledge-based products, but also in improving Korean medicine education, by enhancing the occupational competency bridging basic and clinical knowledge.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.3
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• pp.210-217
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• 2011

Evolution of tip vortex generated by a model rotor blade which has a symmetric blade section has been investigated by use of the laser doppler anemometry. Swirl and axial velocity components of tip vortex were measured by the phase averaging technique within one revolution of a rotor blade. It was found that tip vortex becomes matured until 27 degrees and diffuses afterwards with diffusing rate becoming slower compared to the case of the asymmetric blade section, but the tip loss was expected to become more substantial. Swirl velocity components were well fit to n=2 model of Vatistas within measured wake ages, showing the self-similarity exists for the swirl velocity components. The axial components were followed with Gaussian profiles, but had much higher peak values than those of the symmetric blade section.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.49 no.1
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• pp.13-20
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• 2023

Objectives: Ultra-wide implants may be used as a replacement if existing implants fail. This study was conducted to evaluate the factors influencing the prognosis and failure of ultra-wide implants. Patients and Methods: This study evaluated whether sex, age, site, diameter, length, additional surgery, implant stability (primary and secondary), and reason for ultra-wide implant placement affect the 5-year survival and success rates and marginal bone loss (MBL) of ultra-wide implants. Seventy-eight ultra-wide implants that were placed in 71 patients (39 males and 32 females) from 2008 to 2010 were studied. One-way ANOVA analysis was conducted to evaluate the statistical significance of MBL according to the patient's sex, implant site, and diameter. Independent sample t-tests were used to determine the statistical significance of MBL analysis which was used to determine the significance of the 5-year success and survival rates related to the variables. One-way ANOVA was conducted to evaluate the statistical significance of sex, implantation site, diameter, and MBL. Independent sample t-tests were used to evaluate the correlation between implantability and MBL for implantation reasons, while additional surgery, length, and Kaplan-Meier analysis were used to evaluate 5-year survival and success rates. Results: The mean age of patients was 54.2 years with a survival rate of 92.3% and a success rate of 83.3% over a mean 97.8-month period of observation. MBL averaged 0.2 mm after one year of prosthetic function loading and 0.54 mm at the time of final observation. Success rates correlated with primary stability (P=0.045), survival rates correlated with secondary stability (P=0.036), and MBL did not correlate with any variables. Conclusion: Ultra-wide implants can be used to achieve secure initial fixation in the maxillary and mandibular molar regions with poor bone quality or for alternative purposes in cases of previous implant failure.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.6165-6171
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• 2013

This study aimed to analyze the expression and clinical significance of cyclin G2 (CCNG2) in thyroid carcinoma and the biological effects of CCNG2 overexpression in a cell line. Immunohistochemistry and Western blotting were used to analyze CCNG2 protein expression in 63 cases of thyroid cancer and normal tissues to allow the relationship with clinical factors to be assessed. CCNG2 lentiviral and empty vectors were transfected into the thyroid cancer K1 cell line. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were applied to detect the mRNA and protein levels of CCNG2. MTT assay and cell cycle were also conducted to assess the influence of up-regulated expression of CCNG2 on K1 cell biology. The level of CCNG2 protein expression was found to be significantly lower in thyroid cancer tissue than normal tissues (P<0.05). Western blot: The relative amount of CCNG2 protein in thyroid cancer tissue was respectively found to be significantly lower than in normal tissues (P<0.05), correlating with lymph node metastasis, clinic stage and histological grade (P<0.05), but not gender, age or tumor size (P>0.05). Loss of CCNG2 expression correlated significantly with poor overall survival time on Kaplan-Meier analysis (P<0.05). The results for biological functions showed that K1 cell transfected CCNG2 had a lower survival fraction, a greater percentage in the G0/G1 phases, and lower cyclin-dependent kinase 2 (CDK2) protein expression compared with K1 cells non-transfected with CCNG2 (P<0.05). CCNG2 expression decreased in thyroid cancer and correlated significantly lymph node metastasis, clinic stage, histological grade and poor overall survival, suggesting that CCNG2 may play important roles as a negative regulator in thyroid cancer K1 cells by promoting degradation of CDK2.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.8A
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• pp.950-961
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• 2004

In this paper, we measured and analyzed propagation characteristics in a subway tunnel that is recently increasingly becoming one of the radio communication environments. The measurements are carried out in a subway tunnel with frequency bands of 2.45㎓ and 5.8㎓. The length of tunnel we used for this study is 175m of LOS (Line-of-sight) and 270m of NLOS (Non Line-of-Sight). The subway tunnel is curved and its cross section is horseshoe type. The measurement systems we employ in this study are a narrow-band system and a wide-band system. The narrow-band system is used to get path loss measurement and the wide-band system is used to figure out delay profile measurement. In particular, the wide-band system consists of 1023 length PN sequence generator using a chip rate of 80MHz based on a sliding correlation technique. The omni-directional antennas and directional antennas are used to analyze propagation characteristics for beam type of antenna. The path loss displays only pure path loss of a tunnel environment. The delay profile indicates the mean excess delay and RMS (root mean square) delay spread.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.7
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• pp.675-682
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• 2011

This paper presents two ground plane effects due to the size of two rectangular apertures for two-wire transmission line with equal line length crossing the changeable rectangular apertures in infinite ground planes. The CST MWS is used to determine the characteristics of the insertion loss of the transmission line from the load section in accordance with the ground plane aperture size. The results show that the insertion gain and the insertion loss are periodically observed for the multiple frequency of the half wavelength resonance by the wire length when the transmission line is nearby to horizontal side or vertical side of the aperture. The measurements of the insertion loss are performed to verify the theoretical analysis.

• Magazine of the Korean Society of Agricultural Engineers
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• v.15 no.1
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• pp.2853-2877
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• 1973

Models of cross-sections and channels were made in order to measure seepage losses. Cross-sections were made of sand, sandy clay loam and loam, their thicknesses being 30cm and 40cm, respectively. Flow depths kept in the cross-sections were 4cm, 6cm, 8cm and 10cm. Straight and curved channel models were provided so as to measure seepage losses, when constant water depths maintained at the heads of the channels were 7.3cm and 5.7cm, respectively. The results obtained in this experiment are presented as follows: 1) A cumulative seepage loss per unit length at a point in the channel varies in accordance with time and flow depth. The general equation of cumulative seepage loss may be as follows(Ref. to Table V.25): $$q_{cum}=\int_{o}^aq(a)dt+\int_a^bq(b)dt+\int_b^tq(c)dt$$ 2) In case that the variation of water depth through the channel is slight, the total seepage loss may be computed by applying the following general equation: $$\={q}_{cum}{\cdot}x=\int_o^tq_{cum}\frac{{\partial}x}{{\partial}t}dt$$ 3) Because seepage loss varies considerably according to water depth in case that the variation of flow depth through the channel is great, seepage loss should be computed by taking account of the change of flow depth. 4) The relation between time and traveling distance of water flow may be presented as the following general equation(Ref. to Table V.29): $$x=pt^r$$ 5) The ratios of the seepage losses of the straight channel to the curved channel are 1:1.03 for a flow depth of 7.3cm and 1:1.068 for that of 5.7cm. 6) The ratios of the seepage losses occurring through the bottom to those through the inclined plane in the channel cross-section are 1:2.24 for a water depth of 8cm and 1:2.47 for a depth of 10cm in case that soil-layer is 30cm in thickness. Similarly, those ratios are 1:2.62 and 1:2.93 in case of a soil-layer thickness of 40cm(Ref. to Table V.5).

• Journal of Biomedical Engineering Research
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• v.39 no.6
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• pp.284-296
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• 2018

Obesity is considered as a primary health problem over the past century in line with life environmental changes. It is mainly associated with increased risk of numerous chronic diseases which may significantly reduce health-related quality of life. Therefore, efforts to reduce weight should be performed. This study suggested a novel approach to reduce body fat by applying external stimulation which is micro-current stimulation (MCS). In this clinical study, we evaluated the potential effects of MCS for reduction of abdominal fat and weight loss. Prior to the clinical test, computational simulation was conducted to find the proper MCS conditions that allow externally applied stimulation to reach the internal fat section from the external skin. Particularly, the clinical study evaluated the unilateral effects of MCS for body fat loss and lipolysis without any additional limitations such as physical exercise and dietary therapy. The results showed that whole body fat, waist circumferences, and abdominal fat are gradually decreased after intervention in proportion to the time. From the results, we can estimate that MCS can be effective on the body fat loss by activation of lipolysis in human adipose.