• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.6
• /
• pp.861-866
• /
• 2012

Water is the most important resource for the potato cultivation, especially to get the maximum water use efficiency and yield of potato, Water has to be applied moderately based on the water requirement of the potato. Crop water requirement (WR) is a function of the Potential evapo-transpiration(PET) and Crop coefficient (Kc). PET can be estimated by the climate data measured at the weather station in the production region. Kc was measured by the NIAST (RDA) through Lysimeter experiments. In this study, the growth stage of potato was divided as four (G-1 : Apr. 1~Apr. 15, G-2 : Apr. 16~May. 10, G-3 : May. 11~May. 31, G4 : Jun. 1~Jun. 15). The average PET during potato growing season of the 45 areas was $2.95mm\;day^{-1}$. The most water requirement was the G-3 stage among the potato growth stage. The MWR (Mean water requirement) according to growth stage was 1.0~1.2 (average 1.1), 1.5~1.8 (average 1.6), 1.9~2.2 (average 2.0) and 1.7~2.1 (average 1.8) mm $day^{-1}$, in the G-1, G-2, G-3 and G-4 stage, respectively. The TWR (Total water requirement) according to growth stage was 18.0~22.1 (average 19.3), 50.6~66.6 (average 56.3), 63.5~88.2 (average 72.4) and 38.3~54.5 (average 44) mm, in the G-1, G-2, G-3 and G-4 stage, respectively.

• Journal of Korea Foundry Society
• /
• v.34 no.1
• /
• pp.1-5
• /
• 2014

The austempering transformation behavior in Fe-0.7wt.%C-2.3wt.%Si-0.3wt.%Mn steel is investigated. Each specimen was austenitized for 60 min at $900^{\circ}C$, and austempered at $380^{\circ}C$ for different time periods varying from 2 min to 256 min. After the austempering heat treatment, the Stage I and II evolutions are performed using optical metallography, X-ray diffraction and image analyses. Variations in the X-ray diffraction patterns and lattice parameters of the ferrite and austenite demonstrate that the residual austenite decomposes into ferrite and carbide during the Stage II evolution; moreover the amount of ferrite increases during the Stage I evolution. While the amount of austenite increases during Stage I, it dicreases during Stage II. Overall, the variations in the volume fractions of the microstructure and carbide formation in stages I and II meet high temperature austempering reaction of the ausferrite microstructure.

• Journal of the Korean Society for Precision Engineering
• /
• v.34 no.1
• /
• pp.53-58
• /
• 2017

A fine stage is developed for the 3-DOF error compensation of a linear axis in order to improve the positioning accuracy. This stage is designed as a planar parallel mechanism, and the joints are based on a flexure hinge to achieve ultra-precise positioning. Also, the effect of Abbe's offsets between the measuring and driving coordinate systems is minimized to ensure an exact error compensation. The mode shapes of the designed stage are analyzed to verify the desired 3-DOF motions, and the workspace and displacement of a piezoelectric actuator (PZT) for compensation are analyzed using forward and inverse kinematics. The 3-DOF error of a linear axis is measured and compensated by using the developed fine stage. A marked improvement is observed compared to the results obtained without error compensation. The peak-to-valley (PV) values of the positional and rotational errors are reduced by 92.6% and 91.3%, respectively.

• International Journal of Air-Conditioning and Refrigeration
• /
• v.16 no.3
• /
• pp.77-82
• /
• 2008

For heat pumps used in a cold region, it is very important to obtain appropriate heating capacity. Several studies using a variable speed compressor and an additional heater have been performed to enhance heating capacity at low ambient temperatures. However, for outdoor temperature conditions below $-15^{\circ}C$, it is still difficult to obtain enough heating capacity above the rated value. In recent studies, the application of gas injection technique into a two-stage heat pump yielded noticeable heating performance improvement at low temperature conditions. In this study, the heating performance of a two-stage gas injection heat pump with a rated capacity of 3.5 kW was measured and analyzed by varying refrigerant charge amount and EEV opening at the standard heating condition. The heating performance of the two-stage gas injection heat pump was compared with that of a two-stage non-injection heat pump. The heating capacity and COP of the two-stage gas injection heat pump were improved by 2-10% at the optimal charging condition over those of the two-stage non-injection heat pump.

• Korean Journal of Agricultural Science
• /
• v.31 no.2
• /
• pp.149-160
• /
• 2004

This study had carried out an analysis of leaf tobacco production cost by cost items, growing stages, and farm sizes per 10a to provide the basic data for determination of the purchasing price of leaf tobacco by KT&G. Considering the survey results of 12 tobacco farm households, the composition rates of production cost by items revealed as 7-10% for land service, 5-22% for depreciation, 13-25% for material costs, 50-65% for labour cost respectively. The production cost of leaf tobacco by growing stages were shown as 15.3% in nursery bed period, 32.3% in main growing period in field, 30.8% in harvesting period and 21.6% in packing period. The magnitude of wage expenditure was appeared as harvesting stage, packing stage, growing stage on main field and nursery bed stage in order. The amount of material costs were revealed as the growing stage in main field, harvesting stage, nursery bed stage and packing stage respectively. The production costs of leaf tobacco per 10a by farm sizes were shown as 1,615,879won for small farm, 1,446,896won for medium farm and 1,454,408won for large farm respectively. The production cost of leaf tobacco had shown decreasing tendency according to increasing farm sizes. To promote the international market competitiveness of leaf tobacco producing farms, labour saving production technologies and cost effective farm size to decrease tobacco production cost should be developed.

• Journal of Chest Surgery
• /
• v.25 no.4
• /
• pp.398-405
• /
• 1992

Twenty nine adult patients underwent surgical esohpagectomy and one, bypass procedure for documented carcinoma of esophagus and cadiac portion of stomach at Chonnam National University Hospital from Jan 1986 to April 1991. There were several kinds of esophagectomies including through transhiatal, left thoracotomy only, laparotomy and thoracotomy, and laparotomy and right thoracotomy and cervical incision. Twenty five and squamous cell carcinoma and 5, adenocarcinoma. The tumor locations were the upper third in 3, middle third in 12, lower third in 10 and cardiac portion of stomach in 5. After operation, 8[27%] patients were classified in Stage IIa, 6[20%] patients in Stage IIb, 15 patients[50%] in Stage III and one patient in Stage IV. Major postoperative complications included anastomotic narrowing in 3, limited suture line leak in 2, wound infection in 2, hoarseness in 2, pseudomembraneous enterocolitis in 1 and herpes zoster in 1. There was no death within 30 days of operation. Ten months survival was 100% for patients with Stage lIa, 67% for patients with Stage IIb, 50% for patients with Stage III. Furthermore, 20 months survival was 75% in IIIa, 33% in IIb, and 40% in III. But there were no significant differences in survivals among the stage. The actuarial survival is 58% at one year and 41% at two years, The periods of average survival is 589 days after operation.

• Journal of Power System Engineering
• /
• v.17 no.6
• /
• pp.63-72
• /
• 2013

The main purpose of this study is to analyze the collection characteristics of multi-layer multi-stage porous plate system with ionizer and dielectric-substance experimentally. The experiment is carried out to analyze the characteristics of pressure drop and collection efficiency for the present system with experimental parameters such as applied voltage, inlet velocity, stage number and inlet particle concentration, etc. In results, for multi-layer multi-stage porous plate system of inflow type, at 5 stage and $v_{in}$=2.58 m/s, the pressure drop becomes lower 15 $mmH_2O$ as 95 $mmH_2O$ than that of non-inflow type system. It is estimated that for the present system with ionizer and dielectric-substance, the collection efficiency represents 98.5% showing higher 5.2% comparing to that of multi-layer multi-stage porous plate system without ionizer and dielectric-substance at 5 stage, $v_{in}$=2.58 m/s and inlet concentration $3g/m^3$(fly ash).

• Knowledge Management Research
• /
• v.16 no.3
• /
• pp.149-169
• /
• 2015

In this study, we try to understand the role of online social recommendation and the similarity of preferences between the recommender and the recommendee on consumer decisions in the framework of the two stage purchase decision-making process. Applying construal level theory to our context, we expect that the role of social recommendation and the similarity of preferences would vary over the stages in the two-stage decision making process. To test our hypotheses, we collected the data through an incentive compatible experiment, and analyzed the data with nested logit model. As a result, we found that the role of online social recommendation varies over the stages. Consumers take recommendation from similar others at the stage of consideration set formation, but no longer consider it at the stage of final choice. Consumers take recommendation from dissimilar others at the stage of consideration set formation. At the stage of final choice, however, consumers avoid choosing the option recommended by dissimilar others. The results of our study enrich the understanding about the role of social recommendation, and have implication to marketing practitioners who attempt to make online social recommendation system more efficient.

• Korean Journal of Adult Nursing
• /
• v.25 no.3
• /
• pp.312-321
• /
• 2013

Purpose: The purpose of this study was to compare health promotion behavior, post-traumatic growth and quality of life according to the stages of survivorship in patients with female genital neoplasm. Methods: Data were collected from August 1st, 2011 to September 31st 2011 from 142 gynecologic cancer patients who completed treatment or were treated at an out-patient clinic. The instrument were HPLP developed by Walker, Sechrist & Pender, PTGI developed by Tedeschi & Calhoun, and Korean C-QOL. Results: Health promotion behavior scores were significantly higher in the acute survival stage than the extended survival stage. Post-traumatic growth score was higher in the acute survival stage than the extended survival stage. The quality of life scores were higher in the lasting survival stage than the extended survival stage. Conclusion: Gynecological cancer patients in the extended survival stage reported low scores of health promotion behavior, post-traumatic growth and quality of life. Intervention needed to be developed to improve health promotion behavior, post-traumatic growth and quality of life for patients with female genital neoplasm in the extended survival stage.

• Journal of Chest Surgery
• /
• v.23 no.4
• /
• pp.715-719
• /
• 1990

Thymoma is defined as a neoplasm of the epithelialreticular framework cells of the thymus. The treatment of choice and the prognosis for patients with thymoma are still controversial subjects due to lack of a uniform histological classification and standardized criteria for typing thymic tumors. Between June 1985 and May 1989, eight patients underwent thymomectomy at the Department of Thoracic and Cardiovascular Surgery, Korea University Medical Center. A clinical analysis was performed and the following result was obtained. In histologic cell type, epithelial type was 2 cases, lymphocytic type 3 cases, and mixed type was 3 cases. The clinical stage was classified by Masaoka’s classification that Stage I was 4 cases, Stage II; 2 cases, Stage III; 2 cases and Stage IV was none. Myasthenia Gravis was associated with thymoma in 5 patients. In 8 patients, thymomectomy were performed. Adjuvant radiotherapy was performed in one patient with Stage I due to suspicious tumor remnant and in Stage II, III patients routinely. Combined chemotherapy was performed in one patient with Stage III due to local recurrence. We concluded that the most important prognostic factor of thymoma is extent of tumor invasion. And the presence of Myasthenia Gravis is no more prognostic factor. Surgical resection of thymoma is treatment of choice, If local invasion or distant dissemination is present, postoperative radiotherapy and /or combined chemotherapy is recommended.