• Title/Summary/Keyword: 비 천공율

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STUDIES ON THE MORTALITY OF THE YOUNG BIVALVES, MERETRIX LUSORIA (1) Boring Rates of Drills on the Young Bivalve, Meretrix lusoria (대합 Meretrix lusoria 치패의 폐사에 관한 연구 (1) 대합치패의 천공복족류 Neverita didyma, Natica severa에 의한 천공률에 관하여)

  • LEE Jung Jae
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.2 no.1
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    • pp.63-70
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    • 1969
  • 1. This paper deals with the natural mortality of the early young bivalve, Meretrix lusoria, (less than 13mm in shell length) and the perforations bored in the bivalve by bering snails, Neverita didyma and Natica severa. The investigation was carried out in the Kunsan area and in the laboratory from May to October of 1968. 2. The natural mortality of the field population during this period was $12.1\%$ and among this number $38.1\%$ were drilled by boring snails. 3. The common species of the Naticid gastropods, boring snails-Neverite didyma and Natice severa - are encountered in the habitat of M. lusoria. The perforations drilled by these species were broadly bevelled. 4. The location of the holes on the valves varied widely, while most of holes on the valves were located at a relatively definite umbo position. 5. The inner and outer diameters of the holes varied in proportion to the shell length of the clam; each ranging in shell length from 1 to 3mm, 3 to 6mm, and 6 to 13mm, and the outer diameters were 0.4-0.5mm, 0.7-0.9mm and 0.9-1.2mm. On the other hand, the ratio of the inner and outer diameters differed in proportion to the shell length of the clam. 6. Predation rates of Neverita didyma was much greater at night than during the day at room temperature. An average of 1.7 young clams was drilled and consumed, per snail, per day. This rate was greater than that of the Natica severa. 7 Predation rates varied in proportion to the shell length of the clam and the shell height of the snails.

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The Improvement of Tunnel Construction Cost Standards Considering the Site Conditions in Korea (현장실태를 고려한 국내 터널공사 공사비산정기준 개선)

  • Ahn, Bang-Ryul;Lee, Han-Soo;Oh, Jae-Hoon;Song, Tae-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.8
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    • pp.26-35
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    • 2020
  • Tunnel construction is an important part of Korean public construction projects. Although the development of various equipment and technologies has led to advances in tunnel construction methods that are implemented on sites, the cost standards related to such works do not yet reflect the realities of the construction sites. A literature review and site surveys were conducted to suggest reasonable cost standards for tunnel work that reflects the realities of the field. First, each item in the cost standards for tunnel work, as established in the Construction Standard Production Rates, were analyzed. The results were compared with the actual costs implemented on tunnel projects. The key items analyzed included those regarding the work cycle time, such as rock classification, profiling survey, drilling speed, and muck-disposal processing equipment combination, as well as the number of people put to tunneling work. Based on the site survey results, improved estimates regarding the cycle time per one tunnel drilling blast, drilling speed of the machine, muck disposal processing equipment combination, and the number of people put to tunneling work were suggested. This study suggests the cost standards that reflect the realities of tunneling sites. The results are expected to help ensure adequate costs for tunnel construction projects.

Design of an Area-Efficient Survivor Path Unit for Viterbi Decoder Supporting Punctured Codes (천공 부호를 지원하는 Viterbi 복호기의 면적 효율적인 생존자 경로 계산기 설계)

  • Kim, Sik;Hwang, Sun-Young
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.3A
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    • pp.337-346
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    • 2004
  • Punctured convolutional codes increase transmission efficiency without increasing hardware complexity. However, Viterbi decoder supporting punctured codes requires long decoding length and large survivor memory to achieve sifficiently low bit error rate (BER), when compared to the Viterbi decoder for a rate 1/2 convolutional code. This Paper presents novel architecture adopting a pipelined trace-forward unit reducing survivor memory requirements in the Viterbi decoder. The proposed survivor path architecture reduces the memory requirements by removing the initial decoding delay needed to perform trace-back operation and by accelerating the trace-forward process to identify the survivor path in the Viterbi decoder. Experimental results show that the area of survivor path unit has been reduced by 16% compared to that of conventional hybrid survivor path unit.

The Circular Center Cut with Large Empty Hole & Pre-Splitting in Tunnel Blasting (터널에서 대구경 무장약공과 선균열을 이용한 심빼기 공법에 관한 연구)

  • 김재홍;임한욱
    • Tunnel and Underground Space
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    • v.11 no.3
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    • pp.248-256
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    • 2001
  • The cylindrical cut is most frequently used in tunnel blast regardless of their dimensions. In this study the new parallel cut is proposed to raise advance per round, which is considered to be an elevation of the traditional cylinder cuts. The general geometric pattern of a new cut with parallel blast holes is proposed. The detailed burden and spacing between the central blasthole and those of the four section are also given. The blast results between new cut and traditional cylinder cut are given. The main results of this study are as follows. 1) The average advances per rounds in new cuts can reach 99.5% of drilling length. That of traditional cylinder cuts are known approximately 90∼95% 2) Specific charge weight of new cut compare to that of cylinder cut is approximately reduced 5% from 1.363 to 1.297 kg/㎥ 3) Specific drilling rate is also reduced 8% from 2.393 to 2.130 m/㎥ 4) Vibrations, fly rock, and fragmentation produced by the new blast are to be proved superior to those of the traditional cylinder cuts.

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The effect of different bag materials on grape quality and endeavor of maturation period determination (서로 다른 봉지재료가 포도 품질 및 숙기판단 노력에 미치는 영향)

  • 남상영;강한철;김태수
    • Korean Journal of Plant Resources
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    • v.13 no.2
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    • pp.111-117
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    • 2000
  • In an attempt to select grape bag, which elevates grape quality and make easy maturation period determination, the following research was carried out at Chungbuk Institute of Agricultural Technology, Grape Experiment Station. Light transmittance rate of bag reached to 11-65% with non-woven fabric and non-dripped vinyl bags. Non-dripped vinyl perforation and white painting bag resulted in 50 and 75%, respectively. Berry weights in non-woven fabric and non-dripped vinyl bag were high than that in paper bag. Non-dripped vinyl perforation 50%, white painting bag brought into fruit cracking, shattering, and rotten fruit, making the investigation difficult. Maturation period preceded about 1-4 day with non-woven fabric and non-dripped vinyl compared with that in paper bag. Soluble solids content with non-woven fabric and non-dripped vinyl bags was high and acidity showed a reverse result. Coloring extent was developed rapidly with non-woven fabric and non-dripped vinyl than paper bag. During initial state of coloring, coloring was rapid with Maekban-Stone mixed non-woven fabric and non-dripped vinyl + non-woven fabric bag. This was rapid with non-woven fabric bag as long appropriate maturation period. Abnormal berry rate was 5.4-7.0% with paper and non-woven fabric bags but brought about as much as 16.6-100% with non-dripped vinyl and it's mixed bags. Appearance quality was the best with index 9.0 for non-woven fabric bag. Maekban-Stone mixed non-woven fabric but non-dripped vinyl performance 50% white painting bag was the least, showing index 1.0. The time consumed for maturation determination was reduced to 74-93% with non-woven fabric and non-dripped vinyl bag compared with 17.4h/10a with paper bag.

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A Study on Effective Blasting Patterns on Small Area Tunnel (소단면 터널에서 효율적인 발파 패턴에 관한 연구)

  • Lim, Han-Uk;Kwon, O-Sung
    • Journal of Industrial Technology
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    • v.26 no.A
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    • pp.17-28
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    • 2006
  • In underground drilling and blasting, particularly in small headings(generally under $20m^2$), the prospects for changes of blast parameters are usually more limited than those employed by large area tunnel(over $20m^2$). It is also well known that the consumption of explosives and specific drilling rate for small tunnel areas are exponentially increased also tunnel areas decrease. To confirm above results, some tests for two tunnels(irrigation water tunnel with $6.0m^2$ area, electric supplies tunnel with $15.0m^2$) are also carried out in this study. As a results, specific drilling rate and specific charge for irrigation water tunnel were decreased from 13.8 to $7.7m/m^3$ and from 4.88 to $2.56kg/m^3$ respectively. Those for electric supplies tunnel were also decreased from 8.0 to $4.9m/m^3$ and from 3.46 to $2.22kg/m^3$.

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Design of Daylighting Aperture Using Daylight Factor Method and its Evaluation by Distribution of Sky Component (Daylight Factor Method를 이용한 채광창의 설계)

  • 지철근;권영혜
    • The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.3 no.1
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    • pp.58-63
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    • 1989
  • 이등분한 실의 주광율(Daylight Factor)의 비를 규제도의 지수로서 Lumen Method와 같이 정하고, 이를 만족하는 실의 깊이를 검토한 후, 설계 평균 주광율을 만족하는 창의 면적을 구하였다. 본 논문에서 제안한 창의 면적 자체가 다른 벽면의 면적 변화에 영향을 주고 있음을 고려하지 않은 종래의 방법을 개선하였다. 이후 주광율 요소 중 가장 지배적인 양인 운천공으로부터 입사하는 성분(SCo: Sky Component from overcast Sky)의 분포를 창의 위치와 형태를 변화시켜 조사, 평가하였다.

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Effect of Non-Perforated Breathable Films on the Storability of Sprout Vegetables in Modified Atmosphere Condition (레이저 가공 비천공 Breathable필름이 새싹채소의 Modified Atmosphere 저장에 미치는 영향)

  • Choi, In-Lee;Baek, Jun Pill;Kang, Ho-Min
    • Journal of Bio-Environment Control
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    • v.22 no.2
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    • pp.167-174
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    • 2013
  • Six kinds of sprout vegetables were applied three and six types of non-perforated breathable propylene films (NPB film) for individual and mixed modified atmosphere (MA) package condition at $10^{\circ}C$ on this study. As a tah tasai, kohlrabi, rape, chinese cabbage, red radish, broccoli sprouts were packaged by 20,000, 60,000, and 100,000 $cc{\cdot}m^{-2}{\cdot}day{\cdot}atm$ non-perforated breathable films for seven days storage. Mixed sprout vegetables were used 20,000 cc, 40,000 cc, 60,000 cc, 80,000 cc, and 100,000 $cc{\cdot}m^{-2}{\cdot}day{\cdot}atm$ non-perforated breathable films for seven days storage. Loss rate of fresh weight, changes of carbon dioxide, oxygen, and ethylene gas concentration were measured during the storage. Visual quality and off-flavor were rated by panel tests after seven days storage. Each sprout vegetable storage with film tests had been shown under the 0.5% fresh weight loss in every packaged films, and the 20,000cc NPB film package had been suitable atmosphere condition in the carbon dioxide and oxygen gas concentration. Appearance and off-odor of sprouts packaged with 20,000cc NPB film were shown better than other films because of the proper gas movement through the film to outside during the storage. Fresh weight loss of the mixed sprout vegetables had no difference among the NPB films for seven days storage. The 20,000 cc film had been resulted in that exchange rate of carbon dioxide and oxygen was highest cause of low film permeability than sprouts respiration. But the film is not good for storage because it has been made poor value of off-order even showed high visual quality from panel test after storage. 40,000 cc and 60,000 cc non-perforated breathable films were more suitable for mixed sprout vegetable storage at $10^{\circ}C$. These result suggested that 20,000 cc NPB film was good for single packaged sprout vegetable and 40,000 cc and 60,000 cc non-perforated breathable films were good for mixed packaged sprout vegetable.

Restoration Efficiency Analysis of Expansive Material Implemented Trenchless Underground Cavity Restoration Method Varying Number and Location of Bore Holes (팽창재료를 이용한 지하 공동 비개착 복구공법에서 천공 개수 및 위치에 따른 복구효율 분석)

  • Choi, Byeong-Hyun;Lee, Kicheol;Lee, Junwon;Kim, Dongwook
    • Journal of the Korean Geosynthetics Society
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    • v.18 no.4
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    • pp.25-37
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    • 2019
  • The conventional representative underground cavity restoration methods, which are mainly open-cut methods, require high cost and long period of time for the restoration. Therefore, various trenchless restoration methods have been proposed to improve these disadvantages. The underground cavity restoration method using the expansive material proposed in this paper is one of the trenchless methods. This method fills the underground cavity with high quality backfill soils through the small hole(s) at asphalt layer and compacts backfill soils by insertion of the expansive material within the cavity. In this study, the restoration method using expansive material was constructed in acrylic chamber. The restoration efficiency of the method was analyzed by the fill ratio and degree of relative compaction according to the location and number of bore holes. As a result of the experiment, the restoration efficiency and the optimum construction location were found to be irrelevant.

Changes in the Quality and Physiological Activity of Angelica acutiloba Leaves in Various Packaging Materials during Storage (일당귀 잎의 포장방법이 저장 중 품질 및 생리활성에 미치는 영향)

  • Choi, Ji-Weon;Lee, Ji Hyun;Kim, Won Bae;Kim, Chang-Kug;Jung, Hyun Kyung;Hong, Yoon Pyo;Kim, Ji Gang
    • Korean Journal of Plant Resources
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    • v.30 no.1
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    • pp.29-37
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    • 2017
  • The effect of packaging materials on the quality and physiological activity of Angelica acutiloba leaves during storage at $4^{\circ}C$ for 20 days and after being transferred to room temperature for 2 days was studied. The experiment was conducted using three packaging materials: the corrugated box (control); corrugated box with $20{\mu}m$ HDPE perforated film liner; and corrugated box with paraffin wax coated paper $+20{\mu}m$ HDPE perforated film liner. Changes in weight, color, aroma, overall visual quality, antioxidant activity, and total flavonoids were investigated. Based on the result, the treatments using corrugated box with $20{\mu}m$ HDPE perforated film liner and the corrugated box with paraffin wax coated paper $+20{\mu}m$ HDPE perforated film liner, were effective in minimizing weight loss, and maintaining external color and overall quality as compared to corrugated box only (control). The corrugated box with paraffin wax coated paper $+20{\mu}m$ HDPE perforated film liner was more effective in maintaining antioxidant activity and total flavonoids than other treatments. Prolonging the freshness using corrugated box with paraffin wax coated paper $+20{\mu}m$ HDPE perforated film liner could increase the marketability of Angelica acutiloba leaves in the domestic market.