• Korean Journal of Materials Research
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• v.26 no.2
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• pp.79-83
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• 2016

A commercial NiO (green nickel oxide, 86 wt% Ni) powder was reduced using a batch-type fluidized-bed reactor in a temperature range of 500 to $600^{\circ}C$ and in a residence time range of 5 to 90 min. The reduction rate increased with increases in temperature; however, agglomeration and sintering (sticking) of Ni particles noticeably took place at high temperatures above $600^{\circ}C$. An increasing tendency toward sticking was also observed at long residence times. In order to reduce the oxygen content in the powder to a level below 1% without any sticking problems, which can lead to defluidization, proper temperature and residence time for a stable fluidized-bed operation should be established. In this study, these values were found to be $550^{\circ}C$ and 60 min, respectively. Another important condition is the specific gas consumption rate, i.e. the volume amount ($Nm^3$) of hydrogen gas used to reduce 1 ton of Green NiO ore. The optimum gas consumption rate was found to be $5,000Nm^3/ton$-NiO for the complete reduction. The Avrami model was applied to this study; experimental data are most closely fitted with an exponent (m) of $0.6{\pm}0.01$ and with an overall rate constant (k) in the range of 0.35~0.45, depending on the temperature.

• Korean Journal of Medicinal Crop Science
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• v.22 no.3
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• pp.231-236
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• 2014

This experiment was carried out to establish the optimum cutting time, plant growth regulator, and bed-soil for rooting by greenwood cutting of Schisandra chinensis. Approximately 7 cm long-shoots of greenwood cuttings were transplanted by various cutting times, plant growth regulators, and bed-soils in the plastic-film house. The rooting rate of greenwood cutting was 12.5% in the April 5th, 73.5% in the May 8th, and 75.5% in the August 5th. The number and length of primary root in greenwood cutting were more in the early May than those in the early August. For mass propagation of Schisandra chinensis. using greenwood cutting, shoots were treated with plant growth regulators on May to increase rooting rate. Rooting rate was 100% with IAA $50mg/{\ell}$, 92.9% with NAA $100mg/{\ell}$, and NAA $1,000mg/{\ell}$, for 60 min. To select effective media for rooting, various medias for bed-soil were treated by single and mixture form for 100 days after cutting. Rooting rate was 91.8% in the single treatment of peat moss or decomposition of granite soil, and this result was better than those in other treatment. The treatment by 1 : 1 mixture of peat moss and horticulture bed soil was rooting with 94.0% best rooting rate.

• Horticultural Science & Technology
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• v.35 no.4
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• pp.480-489
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• 2017

We investigated a suitable method for in vitro germination of spores, propagation of prothalli, and the formation of sporophytes in the fern Dryopteris nipponensis Koidz. Spore germination rate was relatively high regardless of culture medium. Prothallus development was faster in Knop medium than in Murashige and Skoog (MS) media. Prothalli used in all experiments were obtained from germinated spores, and were cultivated in different concentrations of media components. The active formation of sexual organs such as antheridium made 1MS medium suitable for prothallus propagation, although there was a lower propagation ratio compared to Knop medium. Growth and morphogenesis of prothalli were most effective on 1MS medium containing 2% sucrose, and 60 mM of total nitrogen source with 20:40 mM ratio of $NH_4{^+}:NO_3{^-}$. To select a suitable soil composition for sporophyte formation, ground prothalli were cultivated on single and mixed soils using bed soil, peat moss, perlite, and decomposed granite for 14 weeks. Bed soil promoted sporophyte formation and growth regardless of single or mixed use. In particular, a mixture of bed soil and decomposed granite in a 2:1 ratio (v:v) led to accelerated sporophyte formation ($0.83/cm^2$).

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.2
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• pp.95-101
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• 2015

The study planned to suggest the efficient methods of system calibration between the range and optical sensors. The simulation was performed by considering i) design of test-bed, ii) mathematical methods of system calibration and iii) locations of the sensors. The test-bed was designed by considering specifications of the range and optical sensors. Also, the error levels of each sensor were considered in the process of simulation with dataset, which was generated under these predetermined conditions. The system calibration was carried out by using the simulated dataset in two different approaches, which are single photo resection and bundle adjustment. The results from the simulation determined that the bundle adjustment method is more efficient than the single photo resection in the system calibration between range and optical sensors. For the better results, we have used the data, obtained in various locations. In a conclusion, the most efficient case was in sequence of i) the bundle adjustment with ii) the simulated dataset, which were obtained between 2m to 4m away from the test-bed.

• Korea Journal of Hospital Management
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• v.21 no.2
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• pp.13-23
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• 2016

Purpose: The purpose of this study is to compare the user satisfaction between 4-bedrooms and 5/6-bedrooms in a single general hospital. Methodology: To measure and compare multiple-bed ward user satisfaction between 4-bedrooms and 5/6-bedrooms, questionnaires were collected from 916 inpatients and 129 nurses in a single general hospital. The patient satisfaction questionnaire categories included environmental conditions, protection of privacy, and medical services. The nurse satisfaction questionnaire categories included space, infection control, patient safety, work load and psychologic view point. Findings: Satisfaction of patient who admitted in 4-bedroom to the environmental conditions and protection of privacy was higher than that of 5/6-bedroom group (3.91 vs. 3.25, p<0.001). Satisfaction of nurse who worked in 4-bedroom was higher than that of 5/6-bedroom (3.05 vs. 1.92, p<0.001). By the multiple linear regression analysis, patient satisfaction to the environmental conditions and protection of privacy was related with multi-bedroom type and location of beds; 4-bedrooms were higher than 5/6-bedrooms(p<0.001), window side bed were higher than hallway side bed(p=0.001). There was no satisfaction difference in comparing medical services between the two groups. By the multiple linear mixed regression analysis, nurse satisfaction who were assigned for 4-bedrooms were higher than that of 5/6-bedrooms in all categories(p<0.001). Practical Implications: Even though no difference has shown in medical services satisfaction between the two patient groups, multi-bedroom type may affect patient satisfaction in environmental condition, protection of privacy and may also affect overall nurse satisfaction. This result suggests that to improve multi-bedroom user satisfaction, 4-bedroom is recommended over 5/6-bedroom.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.3
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• pp.247-255
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• 2022

This paper proposes a multiphase interleaved zero-voltage-transition boost converter with a single soft-switching cell for high-voltage DC-DC converter (HDC) of fuel cell systems. The proposed single soft-switching cell structure can reduce the system volume by minimizing the passive and active elements added even in the multiphase-interleaved structure. To analyze the feasibility of the proposed structure, this paper mathematically analyzes the operation modes of the converter with the proposed single soft-switching cell structure and presents guidelines for design and considerations. In addition, the feasibility of the 210[kW] HDC was confirmed through PSIM simulation, and the system volume reduction of up to 10.48% was confirmed as a result of the 5[kW] HDC test-bed experiment considering the fuel cell system. Through this, the validity of the proposed structure was verified.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.215-216
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• 2000

Granular Bed Filter에서의 미세입자 제거에 대한 연구, 특히 정전기력을 이용한 미세입자의 포집효율에 관한 연구는 수많은 연구자들에 의해 수행되어 왔으나, 이론식 내의 입자들의 관성, 유동장 그리고 입자에 작용하는 전기력의 복합성 때문에 직접적인 일반 해를 구하기가 어려운 것이 사실이다. 정전기력을 이용한 입자의 여과특성 및 효율에 대한 이론적 연구는 주로 외부 전기장을 주었을 경우와 포집체와 입자가 모두 대전되었을 경우를 중심으로 수행되어 왔다. (중략)

• Radiation Oncology Journal
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• v.23 no.3
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• pp.143-156
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• 2005

Background: The best dose-fractionation regimen of the definitive radiotherapy for cervix cancer remains to be clearly determined. It seems to be partially attributed to the complexity of the affecting factors and the lack of detailed information on external and intra-cavitary fractionation. To find optimal practice guidelines, our experiences of the combination of external beam radiotherapy (EBRT) and high-dose-rate intracavitary brachytherapy (HDR-ICBT) were reviewed with detailed information of the various treatment parameters obtained from a large cohort of women treated homogeneously at a single institute. Materials and Methods: The subjects were 743 cervical cancer patients (Stage IB 198, IIA 77, IIB 364, IIIA 7, IIIB 89 and IVA 8) treated by radiotherapy alone, between 1990 and 1996. A total external beam radiotherapy (EBRT) dose of $23.4\~59.4$ Gy (Median 45.0) was delivered to the whole pelvis. High-dose-rate intracavitary brachytherapy (HDR-IBT) was also peformed using various fractionation schemes. A Midline block (MLB) was initiated after the delivery of $14.4\~43.2$ Gy (Median 36.0) of EBRT in 495 patients, while In the other 248 patients EBRT could not be used due to slow tumor regression or the huge initial bulk of tumor. The point A, actual bladder & rectal doses were individually assessed in all patients. The biologically effective dose (BED) to the tumor ($\alpha/\beta$=10) and late-responding tissues ($\alpha/\beta$=3) for both EBRT and HDR-ICBT were calculated. The total BED values to point A, the actual bladder and rectal reference points were the summation of the EBRT and HDR-ICBT. In addition to all the details on dose-fractionation, the other factors (i.e. the overall treatment time, physicians preference) that can affect the schedule of the definitive radiotherapy were also thoroughly analyzed. The association between MD-BED $Gy_3$ and the risk of complication was assessed using serial multiple logistic regression models. The associations between R-BED $Gy_3$ and rectal complications and between V-BED $Gy_3$ and bladder complications were assessed using multiple logistic regression models after adjustment for age, stage, tumor size and treatment duration. Serial Coxs proportional hazard regression models were used to estimate the relative risks of recurrence due to MD-BED $Gy_{10}$, and the treatment duration. Results: The overall complication rate for RTOG Grades $1\~4$ toxicities was $33.1\%$. The 5-year actuarial pelvic control rate for ail 743 patients was $83\%$. The midline cumulative BED dose, which is the sum of external midline BED and HDR-ICBT point A BED, ranged from 62.0 to 121.9 $Gy_{10}$ (median 93.0) for tumors and from 93.6 to 187.3 $Gy_3$ (median 137.6) for late responding tissues. The median cumulative values of actual rectal (R-BED $Gy_3$) and bladder Point BED (V-BED $Gy_3$) were 118.7 $Gy_3$ (range $48.8\~265.2$) and 126.1 $Gy_3$ (range: $54.9\~267.5$), respectively. MD-BED $Gy_3$ showed a good correlation with rectal (p=0.003), but not with bladder complications (p=0.095). R-BED $Gy_3$ had a very strong association (p=<0.0001), and was more predictive of rectal complications than A-BED $Gy_3$. B-BED $Gy_3$ also showed significance in the prediction of bladder complications in a trend test (p=0.0298). No statistically significant dose-response relationship for pelvic control was observed. The Sandwich and Continuous techniques, which differ according to when the ICR was inserted during the EBRT and due to the physicians preference, showed no differences in the local control and complication rates; there were also no differences in the 3 vs. 5 Gy fraction size of HDR-ICBT. Conclusion: The main reasons optimal dose-fractionation guidelines are not easily established is due to the absence of a dose-response relationship for tumor control as a result of the high-dose gradient of HDR-ICBT, individual differences In tumor responses to radiation therapy and the complexity of affecting factors. Therefore, in our opinion, there is a necessity for individualized tailored therapy, along with general guidelines, in the definitive radiation treatment for cervix cancer. This study also demonstrated the strong predictive value of actual rectal and bladder reference dosing therefore, vaginal gauze packing might be very Important. To maintain the BED dose to less than the threshold resulting in complication, early midline shielding, the HDR-ICBT total dose and fractional dose reduction should be considered.

• Journal of Aquaculture
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• v.14 no.1
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• pp.43-50
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• 2001

To study the effect of paddle wheel on water circulation, velocity components were measured in shrimp ponds both along the longitudinal direction from a single paddle wheel and at 25 grid points of two ponds, which have mean water depth of 1.2m and aspect ratio (length/width) 1.05 and 0.68, respectively. An analysis of factors related to water quality and circulation showed that I) a single paddle wheel has an effective distance of 33m for de-stratification, 16m for particulate suspension and 25m for removal of organic material, dispersion of DO and prevention of bed sediment disturbance and ii) with doubling the number of paddle wheels at the pond corners, the flow speed increased by 13% over the ponds, while it reduced by 8.5% around the pond centres. Contrary to expectation, increasing the number of paddle wheel did not generate strong circulation around the pond centre and improve water quality.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.6
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• pp.738-746
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• 1998

This paper presents a neural network-based adaptive controller for a single flexible-link. The control for feedback-error loaming of neural network is designed by using the re-definition approach. The neural network controllers are implemented on an single flexible-link experimental test-bed. The tip response is significantly improved and the vibrations of the flexible modes are damped very fast. Experimental and simulation results are presented of the proposed tip position tracking controllers over the conventional PD-type, passive controllers.