• Korean Journal of Agricultural Science
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• v.10 no.1
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• pp.61-73
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• 1983

This study was conducted to obtain fundamental informations on the improvement of cropping system to increase in land utilization rate and crop production. In order to group the characteristics of areas, Chungnam province was classified into 4 classes: Suburb (Daedeog Gun, Cheonwon Gun), Plain (Nonsan Gun, Dangjin Gun) Coastal (Seosan Gun, Boryeong Gun) and Hilly region (Gongju Gun, Cheongyang Gun). 100 farm households were sampled from each region, and cropping system and utilization state of paddy and upland in 1982 were surveyed. The results obtained were summarized as follows: 1. Average utilization rate of upland was 161.9 % The utilization rate of upland at plain was highest (188.9 %), and that at suburb showed lowest value (152.0%). 2. Number of crops cultivated at upland was 32 kinds. Among the rate of planting area of each crop. soybean showed highest rate of 18.8%, barley 15.4%, red-pepper 13.1% and chinese' cabbage 10.1% respectively, but the red pepper showed highest rate of planting area at suburb, the barley at hilly region and the soybean at plain and coastal region. 3. Average utilization rate of paddy was 115.6% and the utilization rate of paddy at suburb showed the highest value (140.0%) and that at coastal region the lowest value (108.2%). 4. 12 kinds of crops were cultivated at paddy before or after rice cultivation. Among the crops cultivated at paddy before or after rice cultivation, barley showed the highest area rate (5.0%) of cultivation and strawberry the next but the strawberry showed the highest area rate of cultivation at suburb and barley at other regions. 5. The cropping systems at upland were divided into single cropping and double cropping. Types of double cropping at upland were classified into 38 types by the combinations of crops. Among the types of double cropping, the rate of cultivation area of soybean after barley combination was 35.0%, but at suburb the rate of this type of cropping system was low and the double cropping of vegetable combinations showed high rate. 6. Types of double cropping at paddy were classified into 6 types. As a whole, double cropping of barley after rice combination showed highest rate of cultivation area (42.8%) among crop combinations but at suburb, the area rate of this type cropping was low and cultivation of fruit vegetable after rice showed highest rate. The area rate of post - cropping to rice was 76.3% of whole double cropping area at paddy and significantly higher than the rate of precropping to rice. 7. Some kinds of crop combinations were consisted of same family or closely related crops and the characteristics of the crop rotation between those crops are almost same. The area cultivated those unreasonable crop combinations were 19.09 ha. 8. At upland, planting area of the cereal crops, vegetale crops and industrial crops crops and industrial crops was 88.92ha, 93.70ha and 21.80ha respectively. The Planting area of cereal crops was significantly less than that of vegetable crops. 9. Most of all the research reports on the cropping system from 1910 to 1980 were about the post cropping after rice harvest. The objectives of researches could be classified into 14 kinds and the important objectives of researches were the planting time, the amounting of manuring, the quantity of seeding, the transplanting time, the ridging method, the sowing method and the variety test.

• Korean Journal of Agricultural Science
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• v.19 no.1
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• pp.51-64
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• 1992

This experiment was carried out to elucidate the effects of the thyroid function on lactation in female rats. One hundred and five female rats, whose body weight was approximately 250g with normal parturition, were divided into 3.5 THY, 35 PTU, and 35 CON. The $30{\mu}g$ L-thyroxine per rat was administered subcutaneously for the THY group with 3-days intervals arid 0.03% propylthiouracil solution was drunk for the PTU group. After the treatments body weight, thyroid weights and prolactin levels in serum, and histological changes in thyroid and mammary gland were investigated for 3 weeks with 3-days interval. The results obtained were as follows 1. The body weights of PTU group were lower than those of CON arid THY groups. The changes in body weights were significant between 3 and 6 days and between 15 and 18 days. 2. Differences in thyroid weight among the groups were significant after 9 days, The thyroid weights of PTU group were much higher than those of CON and THY group. 3. The follicular epithelia of PTU group after 6 days showed cuboidal phenomena which were accompanied by hypertrophy and hyperplasia, and this phenomena continued until post weaning period. Those of THY group after 9 days showed a squamous degeneration together with pyknosis. 4. The prolactin concentrations of THY group were higher than the other groups after 12 days. and those of CON group were higher than the others after 18 days. However, those of PTU group were lower all through the period. 5. The secretary epithelial cells of THY and CON groups became cuboidal after 12 days, but after 15 days the differentiation of mammary tissue was progressing in THY group faster than CON group. The degeneration of mammary tissue were observed in PTU group as time lapses, so after 15 days the exfoliation of secretory epithelium and atrophy of alveolus were recognized. 6. The body weights of offspring for all experimental groups were increasing as time lapses, but the values for PTU group were markedly lower than the others.

• Tuberculosis and Respiratory Diseases
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• v.44 no.3
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• pp.592-600
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• 1997

Background : The level of imposed work of breathing (WOB) is important for patient-ventilator synchrony and during weaning from mechanical ventilation. Triggering methods and the sensitivity of demand system are important determining factors of the imposed WOB. Flow triggering method is available on several modern ventilator and is believed to impose less work to a patient-triggered breath than pressure triggering method. We intended to compare the level of imposed WOB on two different methods of triggering and also at different levels of sensitivities on each triggering method (0.7 L/min vs 2.0 L/min on flow triggering ; $-1\;cmH_2O$ vs $-2cm\;H_2O$ on pressure triggering). Methods : The subjects were 12 patients ($64.8{\pm}4.2\;yrs$) on mechanical ventilation and were stable in respiratory pattern on CPAP $3\;cmH_2O$. Four different triggering sensitivities were applied at random order. For determination of imposed WOB, tracheal end pressure was measured through the monitoring lumen of Hi-Lo Jet tracheal tube (Mallincrodt, New York, USA) using pneumotachograph/pressure transducer (CP-100 pulmonary monitor, Bicore, Irvine, CA, USA). Other data of respiratory mechanics were also obtained by CP-100 pulmonary monitor. Results : The imposed WOB was decreased by 37.5% during 0.7 L/min on flow triggering compared to $-2\;cmH_2O$ on pressure triggering and also decreased by 14% during $-1\;cmH_2O$ compared to $-2\;cmH_2O$ on pressure triggering (p < 0.05 in each). The PTP(Pressure Time Product) was also decreased significantly during 0.7 L/min on flow triggering and $-1\;cmH_2O$ on pressure triggering compared to $-2\;cmH_2O$ on pressure triggering (p < 0.05 in each). The proportions of imposed WOB in total WOB were ranged from 37% to 85% and no significant changes among different methods and sensitivities. The physiologic WOB showed no significant changes among different triggering methods and sensitivities. Conclusion : To reduce the imposed WOB, flow triggering with sensitivity of 0.7 L/min would be better method than pressure triggering with sensitivity of $-2\;cm\;H_2O$.

• Tuberculosis and Respiratory Diseases
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• v.42 no.6
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• pp.923-933
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• 1995

Background: Pleural abnormality is the the most common respiratory change caused by asbestos dust inhalation and also develop other asbestos related disease after cessation of asbestos exposure. So we conducted epidemiologic study to investigate if the pleural abnormality is associated with pulmonary function change and what factors are influenced on pulmonary function impairment. Methods: Two hundred and twenty two asbestos workers from 9 industries using asbestos in Korea were selected to measure the concentration of sectional asbestos fiber. Ouestionnaire, chest X-ray, PFT were also performed. All the data were analyzed by student t-test and chi-square test using SAS. Regressional analysis was performed to evaluate important factors, for example smoking, exposure concentration, period and the existence of pleural thickening, affecting to the change of pulmonary function. Results: 1) All nine industries except two, airborn asbestos fiber concentration was less than an average permissible concentration. PFT was performed on 222 workers and the percentage of male was 88.3%, their mean age was $41{\pm}9$ years old, and the duration of asbestos exposure was $10.6{\pm}7.8$ yrs. 2) The chest X-ray showed normal(89.19%), pulmonary Tb(inactive)(2.7%), pleral thickening (7.66%), suspected reticulonodular shadow(0.9%). 3) The mean values of height, smoking status, concentration of asbestos fiberwere not different between the subjects with pleural thickening and others, but age, cumulative pack-years, the duration of asbestos exposure were higher in subjects with pleural thickening. 4) All the PFT indices were lower in the subjects with pleural thickening than in the subjects without pleural thickening. 5) Simple regression analysis showed there was a significant correlation between $FEF_{75}$ which is sensitive in small airway obstruction and cumulative smoking pack-years, the duration of asbestos exposure and the concentration of asbestos fiber. 6) Multiple regression analysis showed all the pulmonary function indices were decreased as the increase of cumulative smoking pack-years and especially in the indices those are sensitive in small airway obstruction. Pleural thickening was associated with reduction in FVC, $FEV_1$, PEFR and $FEF_{25}$. Conclusion: The more concentration of asbestos fiber and the more duration of asbestos exposure, the greater reduction in $FEF_{50}$, $FEF_{75}$. Therefore PFT was important in the evaluation of early detection for small airway obstruction. Furthermore pleural thickening without asbesto-related parenchymal lung disease is associated with reduction in pulmonary function.

• Tuberculosis and Respiratory Diseases
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• v.43 no.2
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• pp.201-209
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• 1996

Background : Auto-PEEP which develops when expiratory lung emptying is not finished until the beginning of next inspiration is frequently found in patients on mechanical ventilation. Its presence imposes increased risk of barotrauma and hypotension, as well as increased work of breathing (WOB) by adding inspiratory threshold load and/or adversely affecting to inspiratory trigger sensitivity. The aim of this study is to evaluate the relationship of auto-PEEP with WOB and to evaluate the effect of PEEP applied by ventilator (external PEEP) on WOB in patients with auto-PEEP. Method : 15 patients, who required mechanical ventilation for management of acute respiratory failure, were studied. First, the differences in WOB and other indices of respiratory mechanics were examined between 7 patients with auto-PEEP and 8 patients without auto-PEEP. Then, we applied the 3 cm $H_2O$ of external PEEP to patients with auto-PEEP and evaluated its effects on lung mechanics as well as WOB. Indices of respiratory mechanics including tidal volume ($V_T$), repiratory rate, minute ventilation ($V_E$), peak inspiratory flow rate (PIFR), peak expiratory flow rate (PEFR), peak inspiratory pressure (PIP), $T_I/T_{TOT}$, auto-PEEP, dynamic compliance of lung (Cdyn), expiratory airway resistance (RAWe), mean airway resistance (RAWm), $p_{0.1}$, work of breathing performed by patient (WOB), and pressure-time product (PTP) were obtained by CP-100 Pulmonary Monitor (Bicore, USA). The values were expressed as mean $\pm$ SEM (standard error of mean). Results : 1) Comparison of WOB and other indices of respiratory mechanics in patients with and without auto-PEEP : There was significant increase in WOB ($l.71{\pm}0.24$ vs $0.50{\pm}0.19\;J/L$, p=0.007), PTP ($317{\pm}70$ vs $98{\pm}36\;cm$ $H_2O{\cdot}sec/min$, p=0.023), RAWe ($35.6{\pm}5.7$ vs $18.2{\pm}2.3\;cm$ H2O/L/sec, p=0.023), RAWm ($28.8{\pm}2.5$ vs $11.9{\pm}2.0cm$ H2O/L/sec, p=0.001) and $P_{0.1}$ ($6.2{\pm}1.0$ vs 2.9+0.6 cm H2O, p=0.021) in patients with auto-PEEP compared to patients without auto-PEEP. The differences of other indices including $V_T$, PEFR, $V_E$ and $T_I/T_{TOT}$ showed no significance. 2) Effect of 3 cm $H_2O$ external PEEP on respiratory mechanics in patients with auto-PEEP : When 3 cm $H_2O$ of external PEEP was applied, there were significant decrease in WOB ($1.71{\pm}0.24$ vs $1.20{\pm}0.21\;J/L$, p=0.021) and PTP ($317{\pm}70$ vs $231{\pm}55\;cm$ $H_2O{\cdot}sec/min$, p=0.038). RAWm showed a tendency to decrease ($28.8{\pm}2.5$ vs $23.9{\pm}2.1\;cm$ $H_2O$, p=0.051). But PIP was increased with application of 3 cm $H_2O$ of external PEEP ($16{\pm}2$ vs $22{\pm}3\;cm$ $H_2O$, p=0.008). $V_T$, $V_E$, PEFR, $T_I/T_{TOT}$ and Cdyn did not change significantly. Conclusion : The presence of auto-PEEP in mechanically ventilated patients was accompanied with increased WOB performed by patient, and this WOB was decreased by 3 cm $H_2O$ of externally applied PEEP. But, with 3 cm $H_2O$ of external PEEP, increased PIP was noted, implying the importance of close monitoring of the airway pressure during application of external PEEP.

• Tuberculosis and Respiratory Diseases
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• v.44 no.3
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• pp.559-573
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• 1997

Background : Asthma causes recurrent episodes of wheezing, breathlessness, chest tightness, and cough. These symptoms are usually associated with widespread but variable airflow limitation that is partly reversible either spontaneously or with treatment. The inflammation also causes an associated increase in airway responsiveness to a variety of stimuli. Method : Of the 403 adult bronchial asthma patients enrolled from March 1992 to March 1994 in Allergy Clinics of Severance Hospital in Yonsei University, this study reviewed the 97 cases to evaluate the treatment effects and to analyse prognostic factors. The patients were classified to five groups according to treatment responses ; group 1 (non control group) : patients who were not controlled during following up, group 2 (high step treatment group) : patients who were controlled longer than 3 months by step 3 or 4 treatment of "Global initiative for asthma, Global strategy for asthma management and prevention" (NHLBI/WHO) with PFR(%) larger than 80%, group 3 (short term control group) : patients who were controlled less than 1 year by step 1 or 2 treatment of NHLBI/WHO, group 4 (intermediate term control group) : patients who were controlled for more than 1 year but less than 2 years by step 1 or 2 treatment of NHLBI/WHO, group 5 (long term control group) : patients who were controlled for more than 2 years by step 1 or 2 treatment of NHLBI/WHO. Especially the patients who were controlled more than 1 year with negatively converted methacholine test and no eosinophil in sputum were classified to methacholine negative conversion group. We reviewed patients' history, atopy score, total IgE, specific IgE, methacholine PC20 and peripheral blood eosinophil count, pulmonary function test, steroid doses and aggrevation numbers after treatment. Results : On analysis of 98 patients, 20 cases(20.6%) were classified to group 1, 26 cases(26.8%) to group 2, 23 cases(23.7%) to group 3, 15 cases(15.5%) to group 4, and 13 cases(13.4%) to groups 5. There were no differences of sex, asthma type, family history, smoking history, allergic rhinitis and aspirin allergy among the groups. In long term control group, asthma onset age was younger, symptom duration was shorter, and initial pulmonary function was better. The long term control group required lower amounts of oral steroid. had less aggrevation during first 3months after starting treatment and shorter duration from enrollment to control Atopy, allergic skin test, sputum and blood eosinophil, total IgE, nonspecific bronchial responsiveness was not significantly different among the groups. Seven out of 28 patients who were controlled more than 1 years showed negatively converted methachloine test and no eosinophils in the sputum. The mean control duration was $20.3{\pm}9.7$ months and relapse did not occur. Conclusion : Patients who had asthma of onset age younger, shorter symptom duration, better PFT, lower treatment initial steps, lower amounts of steroid needs and less aggravation numbers after starting treatment were classified in the long term control groups compared to the others.

• Tuberculosis and Respiratory Diseases
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• v.48 no.1
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• pp.14-23
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• 2000

Background: The evaluation of candidates for successful lung resection is important. Our study was conducted to determine the preoperative predictors of postoperative mortality and morbidity in lung cancer patients with impaired lung function. Method; Between October 1, 1995 and August 31, 1997, 36 lung resection candidates for lung cancer with $FEV_1$ of less than 2L or 60% of predicted value were included prospectively. Age, sex, weight loss, hematocrit, serum albumin, EKG and concomitant illness were considered as systemic potential predictors for successful lung resection. Smoking history, presence of pneumonia, dyspnea scale(l to 4), arterial blood gas analysis with room air breathing, routine pulmonary function test were also included for the analysis. In addition, predicted postoperative(ppo) pulmonary factors such as ppo-$FEV_1$ ppo-diffusing capacity(DLco), predicted postoperative product(PPP) of ppo-$FEV_1%{\times}$ppo-DLco% and ppo-maximal $O_2$ uptake($VO_2$max) were also measured. Results: There were 31 men and 5 women with the median age of 65 years(range, 44 to 82) and a mean $FEV_1$ of $1.78{\pm}0.06L$. Pneumonectomy was performed in 14 patients, bilobectomy in 8, lobectomy in 14. Pulmonary complications developed in 10 patients; cardiac complications in 3, other complications(empyema, air leak, bleeding) in 4. Twelve patients were managed in the intensive care unit for more than 48 hours. Two patients died within 30 days after operation. The ppo-$VO_2$max was less than 10 ml/kg/min in these two patients. MVV was the only predictor for the pulmonary complications. However, there was no predictor for the post operative death in this study. Conclusions: Based on the results, MVV was the useful predictor for postoperative pulmonary complications in lung cancer resection candidates with impaired lung function In addition, ppo-$VO_2$max value less than 10 ml/kg/min was associated with postoperative death, so exercise pulmonary function test could be useful as preoperative test. But further studies are needed to validate this result.

• Tuberculosis and Respiratory Diseases
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• v.45 no.5
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• pp.962-974
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• 1998

Background: Alteration of p53 tumor suppressor genes is most frequently identified in human neoplasms, including lung carcinoma. It is well known that bcl-2 oncoprotein protects cells from apoptosis. Recent studies have demonstrated that bcl-2 expression is associated with favorable prognosis for patients with non-small cell lung carcinoma. However, the precise biologic role of bcl-2 in the development of these tumors is still obscure. p53 and bcl-2 have important regulatory influence in the apoptotic pathway and thus their relationship is of interest in tumorigenesis, especially lung cancer. Purpose: The author investigated to know the prognostic significance of the expression of p53 and bcl-2 in radically resected non-small cell lung cancer. Method: 84 cases of formalin-fixed paraffin-embedded blocks from resected primary non-small cell lung cancer from 1980 to 1994 at Hanyang University Hospital were available for both clinical follow-up and immunohistochemical staining using monoclonal antibodies for p53 and bcl-2. Results : The histologic classification of the tumor was based on WHO criteria., and the specimens included 45 squamous cell carcinomas(53.6%), 28 adeonocarcinomas(33.3%) and 11 large cell carcinomas(13.1 %). p53 immunoreactivity was noted in 47 cases of 84 cases(56.0%). bcl-2 immunoreactivity was noted in 15 cases of 84 cases(17.9%). The mean survival duration was $64.23{\pm}10.73$ months in bcl-2 positive group and $35.28{\pm}4$. 39 months in bcl-2 negative group. The bcl-2 expression was significantly correlated with survival in radically resected non-small cell lung cancer patients(p=0.03). The mean survival duration was $34.71{\pm}6.12$ months in p53 positive group and $45.35{\pm}6.30$ months in p53 negative group(p=0.21). The p53 expression was not predictive for survival. There was no correlation between combination of the different status of p53 and bcl-2 expression in our study. Conclusions : The interaction and the regulation of new biologic markers, such as those involved in the apoptotic pathway, are complex. bcl-2 overexpression is a good prognostic factor in non-small cell lung cancer and p53 expression is not significantly associated with the prognostic factor in non-small cell lung cancer.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.2
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• pp.157-168
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• 2008

Statement of problem: Over the past two decades, implant supported fixed prosthesis have been widely used. However, there are few studies conducted systematically and intensively on the splinting effect of implant systems in mandible. Purpose: The purpose of this study was to investigate the changes in stress distributions in the mandibular implants with splinting or non-splinting crowns by performing finite element analysis. Materials and methods: Cortical and cancellous bone were modeled as homogeneous, transversely isotropic, linearly elastic. Perfect bonding was assumed at all interfaces. Implant models were classified as follows. Group 1: $Br{{\aa}}nemark$ length 8.5mm 13mm splinting type Group 2: $Br{{\aa}}nemark$ length 8.5mm 13mm Non-splinting type Group 3: ITI length 8.5mm 13mm splinting type Group 4: ITI length 8.5mm 13mm Non-splinting type An load of 100N was applied vertically and horizontally. Stress levels were calculated using von Mises stresses values. Results: 1. The stress distribution and maximum von Mises stress of two-length implants (8.5mm, 13mm) was similar. 2. The stress of vertical load concentrated on mesial side of implant while the stress of horizontal load was distributed on both side of implant. 3. Stress of internal connection type was spreading through abutment screw but the stress of external connection type was concentrated on cortical bone level. 4. Degree of stress reduction was higher in the external connection type than in the internal connection type.

• Asian Journal of Turfgrass Science
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• v.18 no.4
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• pp.179-191
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• 2004

This study was conducted to find out the effect of sodding and seeding time and rate of seed mixtures on the establishment of cool-season turfgrasses by evaluating the turf coverage rates for two years. In fall planting, the required establishment period of full coverage($100\%$) was 1.5 months with a rolled turf sodding(Kentucky bluegrass $100\%$, Kentucky bluegrass $80\%$+perennial ryegrass $20\%$). The $100\%$ turf establishment was achieved in 7 months with Perennial ryegrass $100\%$, and 7.5 months by seeding with Kentucky bluegrass $100\%$(KB 100), Kentucky bluegrass $80\%$+perennial ryegrass $20\%$(KB80+PR20), Kentucky bluegrass $70\%$+perennial ryegrass $30\%$(KB70+PR30). In spring planting, the establishment periods far sod with KB 100 or KB80+PR20 were taken one month. However, in the case of seeding, the establishment periods were 3 months, 3.5 months, 3.5 months and 4 months with PR100, KB80+PR20, KB70+PR30, and KB 100, respectively Comparing the turf establishment vigor between fall and spring planting, the vigor was higher In spring planting than in fall planting in both sodding and . seeding. In the case of spring planting, the most proper time for turf establishment was tested on April, May, and June trials. The effect was significant in establishment vigor. The result showed highest on April planting. On May and June trials, establishment vigors were decreased gradually As the mixture rate of PR increased, ryegrass, establishment vigor was decreased with the rates. These results indicated that perennial ryegrass has relatively less tolerant to summer heat than Kentucky bluegrass. Number of shoots in 95 days after seeding was higher in KB100 by 16,600 per $m^2$ than in PR100 by 12,400 per $m^2$, while the lowest number showed in KB50+PR50 by 3,300 per $m^2$. Those in KB80:PR20, KB70:PR30 were 6,700 and 4,900 per $m^2$, respectively. The ratios of tillers according to mixture rates between Kentucky bluegrass and perennial ryegrass were KB80:PR20=87:13, KB70:PR30=78:22, and KB50:PR50=48:52. According to results in this study, Ideal seeding time might be spring (April) than in fall (September), and proper mixture rate was $80\%$ of Kentucky bluegrass with $20\%$ of perennial ryegrass.