최적설계 로터 블레이드 형상의 제자리 비행 성능 비교

사정환(J.H. Sa),박수형(S.H. Park),김창주(C.J. Kim),강희정(H.J. Kang),김승범(S.B. Kim),김승호(S.H. Kim) 한국전산유체공학회 2011 한국전산유체공학회 학술대회논문집 Vol.2011 No.11

In this work, a comparative study is performed for simulation of rotor in hovering flight with a 3D compressible Navier-Stokes solver using overlapped grid systems. The shape of rotor blade consists of optimized rotor blade planforms. Optimized blade planforms are designed considering high performance on hovering and forward flight. To show the verification of optimized rotor blade planforms, blade loading(C<SUB>T</SUB>, FM, C<SUB>Q</SUB>) and the vortex behavior of optimized blade shape are compared with original blade shape.

New Zealand 산 도입목초의 강원지역에 있어서 적응성 비교시험

김창주,장병호,이창덕 ( C . J . Kim,B . H . Chang,C . D . Lee ) 한국축산학회 1978 한국축산학회지 Vol.20 No.3

A comparative experiment was carried out in Chunchon and Taekwanryong, Kangwondo to test the adaptability of pasture plants introduced from New Zealand. The New Zealand introduced pasture plants tested in this experiment were orchargass-Apanui(O-A), perennial ryegrass-Ruanui(P-R), Tama ryegrass(Ta), timothy-Kahu(Ti-K), white clover-Huia(W-H), alsike clover(As), red clover-Hamau(R-H) and alfalfa-Wairau(Af-W); besides those plants U.S.A. introduced orchardgrass-Potomac(O-P) and Ladino clover(L), Canada introduced perennial ryegrass-Norlea(P-N) and Australia introduced tall fescue-Demeter (Tf-D) were included in this experiment to compare with the New Zealand introduced pasture plants. The Chunchon experimental field(94m above sea level) was sown on the 8th of May 1977 and the Taekwanryong experimental field(820m above sea level) on the 10th of 1May 1977, and the experiment was carried on until April 1978. The results obtained were summarized as follows: 1. O-A and P-R were slower in early stage growth, lower in the year total yield of dry matter and poorer in wintering record than O-P and P-N respectively. 2. O-A and P-R seemed to unsuitable varieties for the Kangwon area. 3. Ta, which proved to be annual, was thought to be utilized sooner after the sowing because its early stage growth was extremely vigorous. 4. Ta demonstrated abundant production marking 10.99 t/㏊ in the year total yield of dry matter in the Taekwanryong experimental field. Nevertheless, Ta`s summering record was inferior in the Chunchon experimental field. 5. In the both experimental fields of Chunchon and Taekwanryong, Ti-K showed a poor record in summering and presented a low year total yield of dry matter but it was found to be outstanding in winter survival. 6. W-H was regarded to have the strongest winter hardiness among the legume plots, yet it marked rather a lower dry matter yield. 7. It is presumed that R-H will find no difficulty in wintering even in the alpine region but will fall into trouble in summering in the lowlands. 8. Af-W made poor growth in both the Chunchon and Taekwanryong experimental field. 9. Though L recorded the highest year total yield of dry matter among the legume plots, most of L were winterkilled in the Taekwanryong experimental field. 10. O-P and Tf-D presented comparatively good record in summering and wintering, and Tf-D showed the highest year total yield of dry matter in the Chunchon experimental field presenting 6.01 t/㏊. 11. P-N and As revealed comparatively strong winter hardness even in the Taekwanryong experimental field. 12. In the year total yield of dry matter the Taekwanryong experimental field was larger than the Chunchon experimental field by 79.1% in the grasses and by 13.8% in the legumes.

Cognitive Radio 기술 동향

김창주,Kim, C.J. 한국전자통신연구원 2006 전자통신동향분석 Vol.21 No.4

유비쿼터스 정보화사회의 도래와 함께 한정된 주파수자원에 대한 수요가 증가됨에 따라 이를 효율적으로 이용하기 위한 기술이 더욱 각광을 받고 있다. 이중에서도 스펙트럼 환경을 측정하여 사용하지 않은 주파수를 선정, 기존의 전파환경과 양립하면서 통신을 하는 CR 기술은 미래 무선통신의 핵심 기술로 인식되고 있다. CR 기술은 SDR 기술을 기반으로 스펙트럼 센싱(spectrum sensing) 기능을 활용하여 가용한 주파수를 선정하여 통신하는 기본적인 기능과 여러 가지 환경 파라미터를 지속적으로 업데이트하는 learning algorithm이 합쳐진 기술이다. 본 고에서는 CR 기술을 설명하고, CR의 응용으로 현재 표준화가 진행되고 있는 IEEE 802.22 WRAN 표준화 활동과 WG에서 검토되고 있는 기술, 즉 physical layer, MAC layer, 그리고 spectrum sensing의 주요기술을 소개한다.

대관령지역에 있어서 낙농가를 위한 청예용 사초생산에 관한 연구 1 . 사초용유채 ( Brassica napus Subsp . oleifera ) 의 적응성 및 파종시기에 관한 시험

김창주(C . J . Kim),김병완(B . W . Kim) 한국축산학회 1987 한국축산학회지 Vol.29 No.7

This experiment was conducted as a part of the studies on the soiling forage production for the dairy farm in the Taekwanryong area, to investigate the adaptability of forage rape and determine the proper time of sowing in the Taekwanryong area. Two cultivars of forage rape (Brassica napus Subsp. oleiferaJ, Akela and Ramon, and a cultivar of oilseed rape, Halla, were sowed at intervals of about 10 days according to the treatment plan from the early August to the early October 1986 on the experimental field (815m above sea level) located Hoengke-ri Toam-myon Pyongchang-gun Kangwon-do, Korea. The results obtained were summarized as follows: 1. In Taekwanryong area, Ramon showed apparently higher adaptability than Akela, while Halla the lowest adaptability among the three cultivars. 2. In Taekwanryong area, the forage rape for soiling should be sowed not later than late August, and`for grazing not later than early September. 3. In Taekwanryong area, it is thought that the sowing and growing of the forage rape will be possible in summer season. 4. In Taekwanryong area, if the forage rape is grown as a second cropping on the fallow fields of cool high3and summer vegetables, it is expected that land productivity will be raised. 5. In plant length measured at the harvesting time, 70 days after the sowing, Akela marked 49.3㎝, 32.8∼36.9㎝, and 19.2㎝ in the plot sowed early August, middle and late August, and early September respectively; while Ramon was longer than Akela by average 3.2㎝ through those plots. 6. In fresh forage yield, harvested 70 days after the sowing, Akela recorded 47.73t/㏊, 27.78∼32.60t/㏊, and 17.18t/㏊ in the plot sowed early August, middle and late August, and early September respectively; while Ramon yielded more than Akela by average 6.38t/㏊ through those plots. 7. In dry matter yield, harvested 70 days after the sowing, Akela and Ramon produced respectively 6.48t/㏊ and 7.11t/㏊ in the early August sowing plot, 4.50∼4.82t/㏊ and 5.37∼5.68t/㏊ in the middle and late August sowing plot, and 2.84t/㏊ and 3.32t/㏊ in the early September sowing plot. 8. The plot sowed middle September presented scanty yield with 3.05∼4.82t/㏊ in fresh forage yield, and 0.52∼0.86t/㏊ in dry matter yield; while the plots sowed later than the middle September marked only trace in both fresh forage and dry matter yield. 9. Dry matter ratio measured at the harvesting time recorded 16.2% in Akela, 15.2% in Ramon and 14.2% in Halls.

종근의 크기와 재직방법이 Russian Comfrey ( Symphytum peregrium LEDEB . ) 의 발아 및 초기생육에 미치는 영향

김창주 ( C J Kim ),윤익석 ( I S Yun ) 한국축산학회 1973 한국축산학회지 Vol.15 No.1

Experiments were carried out to determine the effects of size and planting method of seed root on the sprout and early stage growth of Russian Comfrey(Symphytum peregrinum LEDEB.) during the period of 8 weeks from April to July 1972 at Kangwon National University, Chunchon. The seed roots used in the experiments classified into 3 classes of diameter of 0.5㎝, 1.5㎝ and 2.5㎝, and 4 classes of length of 2㎝, 5㎝, 8㎝ and 11㎝, and the seed roots were planted in 3 kinds o method, vertical planting, horizontal planting and reversed vertical planting. The results are summarized as follows: 1. Sprout percentage was higher and early stage growth was better with thicker and longer seed root. 2. In sprout percentage and early stage growth 0.5㎝-diameter plot was definitely inferior to 15㎝-diameter plot, and 2㎝-length plot was to 5㎝ and over-length plots(p$lt;0.05). But 1.5㎝-diameter plot was not significantly inferior to 2.5㎝-diameter plot, and 5㎝-length plot was not to 8㎝ and over-length plots in sprout percentage and early stage growth. 3. 1.5㎝-diameter. 5㎝-length was considered as adquate size of seed root. Showing 89.7% of sprout percentage, 28.0㎝ of leaf length, 7.2g of tops DM weight and 6.8g of roots DM weight at 8th week, 1.5㎝-diameter·5㎝-length plot did not fall so far behind those plots planted with seed roots which were bigger than that of 1.5㎝-diameter·5㎝-length plot in sprout percentage and early stage growth. 4. It seemed that sprout percentage and early stage growth were being improved by means of increasing in length in the seed root of small diameter or increasing in diameter in the seed root of short length. A thin and long seed root, however, seemed to show comparatively higher sprout percentage and better early stage growth rather than a thick and short one (p$lt;0.05). 5. Sprouting and early stage growing records made by the seed roots of every class of diameter stood in order of vertical planting]horizontal planting]reversed vertical planting. 6. On account of good sprout percentage and early stage growth, saving labor for planting and no probability of reversed planting the horizontal planting was thought as recommendable method. In. sprout and early stage growth, the reversed vertical planting was definitely inferior to the vertical planting and to the horizontal planting (p$lt;0.01). 7. 1.5㎝-diameter·horizontal planting plot was thought as the plot planted with the adquate seed root of thickness and the suitable planting method. Displaying 85.0% of sprout percentage, 27.0㎝ of leaf length, 6.6g of taps DM weight and 6.0g of roots DM weight at 8th week, the 1.5㎝-diameter·horizontal planting plot were not significantly worse in sprout percentage and early stage growth than the plots planted with the seed roots of above 1.5㎝-diameter in vertical or in horizontal method.

재식밀도가 Russian Comfrey ( Symphytum Peregrinum Ledeb ) 의 수량 및 엽생장에 미치는 영향

김창주 ( C J Kim ),채영석 ( Y S Chae ),정계완 ( K W Cheong ) 한국축산학회 1972 한국축산학회지 Vol.14 No.1

To investigate how to influence planting density on yield and leaf growth of Russian Comfrey an experiment was carried out for 2 years from 1969 to 1970 at Kangwon National University. The results were summarized as follows: 1. Green top yield increased according as planting density increased. The yield was 9,563㎏/10a in 30×60㎝ plot, 8,247㎏/10a in 60×60㎝ plot, 6,464㎏/10a in 60×90㎝ plot, 4,922㎏/10a in 90×90㎝ plot and 4,266㎏/10a in 90×120㎝ plot. 2. In accordance with increase of planting density, ratio of petiole length and ratio of petiole weight increased while ratio of leaf-blade length and leaf-blade weight decreased. Ratio of petiole weight was 33.3% in 30×60㎝ plot, 25.5% in 60×60㎝ plot, 21.4% in 60×90㎝ plot, 19.9% in 90×90㎝ plot and 19.3% in 90×120㎝ plot. 3. Significant difference of ratio of petiole length and weight was not found among the plots which were wider than 60×90㎝ (1,800 stumps/10a) in inter-row spacing. 4. Considering both the yield and utility value of the leaf, 60×60㎝ (2,700 stumps/10a) was thought adequate planting density. 5. Petiole was lower than leaf-blade in nutritive value. 6. In dense planting yield was high but feeding value of the leaf was low due to high ratio of petiole weight.

Orchardgrass 및 Ladino clover 목초지에 있어서 목초와 바랭이 ( Digitaria sanguinalis [ L . ] Scop . ) 간의 경합에 관한 연구

김창주 ( C . J . Kim ) 한국축산학회 1974 한국축산학회지 Vol.16 No.3

To investigate the competition mechanisms between pasture plants and crabgrass in orchardgrass and Ladino clover swards and to find effective protectional method of the pasture plants from the competition between crabgrass, a series of following experiments was carried out during the period from April 1973 to October 1913 at Kangwon National University, Chunchon. Experiment 1. the growth and development of crabgrass in orchardgrass/Ladino clover mixtures with different vegetations Experiment 2. the influence of crabgrass on the growth of pasture plants in orchardgrass and Ladino clover swards Experiment 3. the factors affecting the competition between crabgrass and orchardgrass, and Ladino clover Experiment 4. the effects of cutting frequency and cutting height in summer season on the vegetations in orchardgrass and Ladino clover swards mixed with crabgrass The results are summarized as follows: Experiment 1. 1. The crabgrass seeds buried in 1㎡ of orchardgrass/Ladino clover mixtures numbered 530∼610 under good vegetation, 670, poor vegetation and 790, barren place respectively. 2. A rush grow th of crabgrass was observed where the density of pasture plants w as low or the pasture sward was barren, but dominance ratio of pasture plants did not show any significant effects on the growth and development of crabgrass. 3. Dry matter production of crabgrass recorded 12 g/㎡ in the pasture dominated by orchardgrass, 35 g/㎡ in the pasture dominated by Ladino clover and 1,252 g/㎡ in the barren place. Experiment 2. 1. Crabgrass seedlings in the spring sown pasture 6 weeks after seeding were counted to 70∼120 plants/㎡. 2. The most of orchardgrass was smothered where crabgrass was not removed, but in case of Ladino clover the smothering effect of crabgrass was not apparent compared with the case of orchardgrass. 3. Dry matter yield of last cut of orchardgrass in the plot not-removed crabgrass (0.14 t/㏊) was significantly (P$lt;0.05) lower than that in the plot completely-removed crabgrass (3.90 t/㏊). However, the dry matter yield of Ladino clover in the plot not-removed crabgrass (1.49 t/㏊) did not show any difference with that in the plot completely removed crabgrass (1.73 t/㏊). On the other hand the plot mono-cultured crabgrass produced 0.66 t/㏊. 4. It was found that abundant fertilization of nitrogen in mid summer seemed to be unfavorable for growth of orchardgrass on account of increased competive ability of crabgrass. Experiment 3. 1. In pot culture, root competition was observed clearly but shoot competition was not found apparently. 2. In root competition, pasture plants was depressed by crabgrass in summer but the competition was not occurred in autumn. In dry matter production of crabgrass, the plot not-separated is root competition produced 2.4∼2.6 times (P$lt;0.05) more than the plot separated in root competition in mid summer (high temperature condition), while significant difference was not found in autumn (low temperature condition). In high soil moisture condition, both pasture plants and crabgrass made vigorous growth in summer but only pasture plants continued the vigorous growth in autumn crabgrass gave no response to different soil moisture conditions in autumn. Experiment 4. 1. Data revealed that pasture plants affected harmfully by the cutting treatment which was practiced to control crabgrass in mid summer when pasture plants were depressed. 2. Cutting treatment resulted to control crabgrass beared less meaning in Ladino clover sward. 3. Relatively frequent high cutting, such as 20 days cutting interval and 12㎝ cutting height, was thought to be effective to some extent on control of crabgrass in asture swards. From the results of the series of four experiments, firstly, it is concluded that pasture swards should be maintained to keep high density of pasture plants which prevents the invasion of crabgrass. Secondly, it is also suggested that the stage of seedling establishment shou

대관령지역에 있어서 Alfalfa ( Medicago sativa L . ) 생산에 관한 연구 1 . 붕소 및 석회시용이 Alfalfa 생육 및 수량에 미치는 영향

김창주(C . J . Kim),김병완(B . W . Kim) 한국축산학회 1990 한국축산학회지 Vol.32 No.6

This experiment was carried out as a part of the studies on the alfalfa(Medicago sativa L.) production in Taekwanryong area to examine the effects of boron and lime application on the growth and yield of alfalfa. Vernal cultivar of alfalfa was sown on 18. August, 1987 on the experimental field(850m above sea level) located in Hoengke-2-ri Toam-myon Pyongchang-gun Kangwon-do, Korea, and the alfalfa was cut four times from 5. June to 30. September in the first harvest year, 1988. The plot of born application consisted of 0 kg/ha, 5kg/ha, 10kg/ha, 20kg/ha, 30kg/ha, 40kg/ha and 50 kg/ha of borax application, and the plot of lime application consisted of non-lime application and 3000kg/ha of lime application. The results obtained were summarized as follows; 1. The yield of alfalfa was strikingly increased by the lime application(p $lt;0.05). The lime application plot marked 74.86t/ha of annual fresh forage yield and 11.71t/ha of annual dry matter yield, while the non-lime application plot showed 34.05t/ha of annual fresh forage yield and 5.73t/ha of annual dry matter yield. 2. The wintering ability of alfalfa was remarkably improved by the lime application. In winter survival ratio of the shoots, the lime application plot recorded 66.3%, while the non-lime application plot showed 42.2%. 3. The lime application proved to be definitely effective in accelerating especially the early stage growth of alfalfa. Plant length, surface coverage and density measured at the first cut in the first harvest year were 26.4cm, 74.4% and 124.7stems/dm² respectively in the non-lime application plot, while they were 48.0cm, 100% and 262.lstems/dm² respectively in the lime application plot. 4. In dry matter ratio, significant differences were not recognized among the treatment plots, but a little differences were found among the cutting times through a year. The highest dry matter ratio of 18.6% was recorded at the first cutting time and the lowest ratio of 14.3% was marked at the second cutting time. 5. In dry matter yield, the boron application plots marked higher than the non-boron application blot by 2∼8% in the lime application plot, while the former plots recorded higher than the latter by 5∼46% in the non-lime application plot(p $lt;0.05). 6. Optimum level of boron application seems to be 20∼40kg/ha of borax. 7. Dry matter yield did not uniformly increased in proportion to the increas of boron application. 8. In Taekwanryong area, 3000kg/ha of time application presented decidedly positive effect in augmenting the productivity of alfalfa, nevertheless the efficacy of boron application appears to need further close study. 9. In Taekwanryong area, the alfalfa production is expected to have a bright future.

Perennial ryegrass 의 파종비율 및 예취빈도가 혼파목초의 정착 및 성장에 미치는 영향

김창주 ( C . J . Kim ) 한국축산학회 1975 한국축산학회지 Vol.17 No.5

An experiment was conducted to investigate how to effect the cutting frequency and perennial ryegrass seeding rate on the establishment and growth of the pasture plants in the swards of orchardgrass(20㎏/㏊)/Ladino clover(3㎏/㏊)mixture associated with perennial ryegrass at five different seeding rate of 0㎏/㏊, 5㎏/㏊, 10㎏/㏊, 20㎏/㏊ and 30㎏/㏊. The seeds mixtures were sown in April 1972 and the swards were cut at two different cutting frequency of 2-time/year and 4-time/year, and the experiment was carried out over a period of two years at Kangwon National Lniversity, Chunchon. The results obtained were summarized as follows: 1. Establishment ratio of orchardgrass was not dropped by adding perennial ryegrass up to 20㎏/㏊, yet the ratio was dropped notably by adding 30㎏/㏊ of the ryegrass. Establishment ratio of Ladino clover tended to drop as the seeding rate of the ryegrass increased. 2. In the first year, length of the pasture plants had a trend to shorten as the seeding rate of perennial ryegrass raised. But the effect of seeding rate of the ryegrass on the plants length was not found in the second year. 3. In summer season, perennial ryegrass seemed to be placed at a disadvantage in light competition since plant length of the ryegrass was shorter than that of orchardgrass by 20∼30㎝ in the 4-time cut plot and 50∼60㎝ in the 2-time cut plot. 4. In the 2-time cut plot, pasture plants lodged at every cut except the first cut in the first year. The lodging was due to such a excessively long plant length as 90∼110㎝ in orchardrass. It was too infrequent to cut two time in a year. 5. As the cutting frequency lowered, or the seeding rate of perennial ryegrass raised relative light intensity in the plant community had a tendency to descent. 6. During the summering period in the first year, decreasing rate of tiller or stolon number marked 27.5% in orchardgrass, 98.4% in perennial ryegrass and 41.0% in Ladino clover in the 2-time cut plot while 5.6% in orchardgrass, 89.1 in perennial ryegrass and 24.8% in the 4-time cut plot. The 2-time cut plot was remarkably higher than the 4-time cut plot in the decreasing rate of tiller or stolon number. 7. During the wintering period in the first year, orchardgrass increased by 56.8∼71.9% in tiller number and Ladino clover increased by 46.1∼99.0% in stolon number but the tiller number of perennial ryegrass were seemed to be decreased. Generally perennial ryegrass existed till spring time of the second year. 8. The seeding rate of perennial ryegrass assent density of orchardgrass and Ladino clover had a trend to drop in the first year, yet such a trend was not noticed in the second year. 9. In LAI of the mixture swards, the 2-time cut plot was larger than the 4-time cut plot (P$lt;0.05). The 2-time cut plot showed 9.94 and the 4-time cut plot showed 5.74 in the first year, and the 2-time cut plot showed 8.49 and the 4-time cut plot showed 6.31 in the second year. 10. In the first year, before the midsummer LAI of the mixture swards had a tendency to increase in proportion to rising the seeding rate of perennial ryegrass while after the midsummer it had a tendency to increase in proportion to decreasing the seeding rate of the ryegrass. 11. In the first year, LAI of the orchardgrass increased as the seeding rate of perennial ryegrass lowered. 12. When 20∼30㎏/㏊ of perennial ryegrass is added to the mixture early stage production of the sward expected to increase significantly.

질소 , 인산 , 가리 및 석회시용이 Korean Lespedeza ( Lespedeza stipulacea MAXIM ) 의 생장 , 수량 및 식물체성분과 토양성분에 미치는 영향

김창주 ( C J Kim ),윤익석 ( I S Yun ),한기영 ( K Y Han ),채현석 ( H S Chae ) 한국축산학회 1972 한국축산학회지 Vol.14 No.4

An experiment was carried out from June to August 1971 at Institute of Korean Grassland Development, Konkuk University to investigate how to effect N, P₂O_5, K₂O and CaO application on the growth, yields and plant components of Korean lespedeza(Lespedeza stipulacea M_(AXIM)) and on the soil components. The results were summarized as follows: 1. Lime and phosphate were definitly effective on the growth and yields. Phosphate was more effective than lime. 2. Nitrogen was not effective to the growth and yields. Abundunt application of nitrogen was thought to deter the growth and to decrease the yields. 3. Effects of potash were not appreciated when it was used alone, nevertheless the effects were apparent when it was used together with phosphate. 4. NPK Ca-plot showed the best growth and the largest yield among all plots(P$lt;0.05) Significant differences were not found among the plots of P, Ca, and NPK(P$gt;0.05). 5. Compound fertilization of P-K-Ca without N was thought to be more economical and effective. 6. Potash seems to act effectively in increasing root DM weight. 7. Percentages of the plant components were not changed significantly by fertilization. 8. Exchangeable Ca and K of the soil were increased by application of lime.