• Title/Summary/Keyword: Breaking Time

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Analysis on Morphological Characters and Germination Conditions of Seeds in Ledum palustre var. diversipilosum (백산차(Ledum palustre var. diversipilosum) 종자의 형태적 특성 및 발아조건 분석)

  • Young-Min Choi;Seung-Ju Jo;Hyun-Ji Lee;Myung-Ja Kim;Jung-Won Sung;Jung-Won Yoon
    • Proceedings of the Plant Resources Society of Korea Conference
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    • 2023.04a
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    • pp.23-23
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    • 2023
  • The Hairy labrador tea (Ledum palustre L. var. diversipilosum Nakai) is a evergreen small shrub, belonging to the Ericaceae and mainly distributed along the alpine areas of Hamgyeong-do in North Korea. Through seed physiological research on North Korean plants, we intend to obtain basic data for the development of mass propagation methods and use them for vegetation restoration. The internal and external morphological characters of the seed were observed using scanning electron microscopy or stereoscopy, and full seeds were selected through X-ray test. Seeds were cultured on a growth condition at 15/6℃ and 25/15℃ to examine the germination response according to temperature, and the number of germinated individuals was examined every 24 hours to calculate germination percentage and mean germination time. Low-temperature treatment (4℃) and hormone treatment (GA3) were performed to investigate the effect of dormancy breaking, and analysis of variance (ANOVA) was performed on the experimental results using SAS 9.4. The seeds of the Hairy labrador tea were elliptical-narrow in shape, and the epidermal cell wall pattern was reticulated. The final germination rate (FGP) was the highest at 58.9% under the condition of low temperature treatment at 25/15℃. The average number of days to germination (MGT) was the highest at 25.1 days without treatment at 15/6℃, and the average of the last germination days was confirmed to be about 13 days. As a result of low temperature treatment, it was confirmed that the final germination rate (FGP) increased by 43.3%. The significance of the final germination rate (FGP) was verified according to the pretreatment at 25/15℃.

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A Study on the Strength Evaluation Method of Submersible Mooring Pulleys for Detachable Mooring Systems (탈착계류시스템 반잠수식 무어링 풀리의 구조강도평가법에 관한 연구)

  • Kangsu Lee;Byoungjae Park
    • Journal of Wind Energy
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    • v.15 no.1
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    • pp.91-102
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    • 2024
  • Rapid progress is being made in foundational technology research and engineering for the construction of floating offshore wind farms. There is active development of technology for detachable mooring systems, which have strengths in addressing maintenance issues that arise in floating offshore wind farms and enhance their economic viability. Conventional detachable mooring systems use Kenter links inserted into the middle of mooring chains, which require excessive time for retrieval by Anchor Handling Tug Supply (AHTS) vessels during detachment operations. Moreover, these operations pose risks of link damage and accidents. Therefore, there is a demand for the development of a new concept of detachable mooring systems. The proposed detachable mooring system in this study simultaneously integrates a fairlead chain stoppers (FCS) and submersible mooring pulleys (SMP), which enables all operations to be conducted on the AHTS vessel without underwater tasks. This study detailed the design and safety evaluation of the SMP, a core component of the detachable mooring system, based on the minimum breaking load (MBL) of selected mooring lines according to the capacity of the floating platform. It referenced international codes (AISC Specification for Structural Steel Buildings D5, Pin-Connected Members) for design verification and performed finite element analysis to evaluate the strength of major components in installation and operation scenarios. Additionally, procedures and techniques for evaluating the structural strength of components under uncertain boundary conditions were proposed.

Characteristics of reoxidation of nitried oxide for gate dielectric of charge trapping NVSM (전하트랩형 NVSM의 게이트 유전막을 위한 질화산화막의 재산화특성에 관한 연구)

  • 이상은;한태현;서광열
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.11 no.5
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    • pp.224-230
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    • 2001
  • The characteristics of $NO/N_2O$ annealed reoxidized nitrided oxide being studied as super thin gate oxide and gate dielectric layers of Non-Volatile Semiconductor Memory (NVSM) were investigated by Dynamic Secondary Ion Mass Spectrometry (D-SIMS), Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), and Auger Electron Spectroscopy (AES). The specimen was annealed by $NO/N_2O$ after initial oxide process and then rcoxidized for nitrogen redistribution in nitrided oxide. Out-diffusion of incorporated nitrogen during the wet oxidation in reoxidation process took place more strongly than that of the dry oxidation. It seems to indicate that hydrogen plays a role in breaking the Si N bonds. As reoxidation proceeds, incorporated nitrogen of $NO/N_2O$ annealed nitrided oxide is obsen-ed to diffuse toward the surface and substrate at the same time. ToF-SIMS results show that SiON species are detected at the initialoxide interface, and Si,NO species near the new $Si_2NO$ interface that formed after reoxidation. These SiON and $Si_2NO$ species most likely to relate to the origin of the state of memory charge traps in reoxidized nitrided oxide, because nitrogen dangling bonds of SiON and silicon dangling bonds of $Si_2NO$ are contained defects associated with memory effect.

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Effects of Feeding Time and Frequency on the Performances of Broiler Breeder Hens (사료의 급여시간 및 급여회수가 육용종계의 산란능력에 미치는 영향)

  • 이규호;이상진;이종선;정선부
    • Korean Journal of Poultry Science
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    • v.15 no.2
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    • pp.73-79
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    • 1988
  • In order to study the effects of feeding time (08:00 and 14:00 hours) and frequency (once a day, twice a day and once every other day) on the performances of broiler breeder hens, two experiments were conducted with 1, 248 hens of Maniker strain during 24-2 weeks (Experiment 1) and 42-60 weeks (Experiment 2) of age. The results obtained are summarized as follows : 1. No significant differences were observed in hen-day egg production and feed conversion rate between feeding times or among feeding frequencies through the entire experimental period. 2. Mean egg weight during the age of 24-42 weeks was significantly increased by feeding in the afternoon (p<0.01). But it was not significantly affected by feeding time or frequency during 42-60 weeks of age. 3. Fertility and hatchability of eggs at 36 weeks and 60 weeks of age were not significantly different among treatments. 4. By feeding in the afternoon egg breaking strength at 60 weeks of age was significantly improved (p<0.05), but not at 36 weeks of age. 5. In diurnal distribution of egg production, hens fed in the afternoon produced more eggs in the afternoon than hens fed during the morning (p<0.01).

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Detection Method for Bean Cotyledon Locations under Vinyl Mulch Using Multiple Infrared Sensors

  • Lee, Kyou-Seung;Cho, Yong-jin;Lee, Dong-Hoon
    • Journal of Biosystems Engineering
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    • v.41 no.3
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    • pp.263-272
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    • 2016
  • Purpose: Pulse crop damage due to wild birds is a serious problem, to the extent that the rate of damage during the period of time between seeding and the stage of cotyledon reaches 45.4% on average. This study investigated a method of fundamentally blocking birds from eating crops by conducting vinyl mulching after seeding and identifying the growing locations for beans to perform punching. Methods: Infrared (IR) sensors that could measure the temperature without contact were used to recognize the locations of soybean cotyledons below vinyl mulch. To expand the measurable range, 10 IR sensors were arranged in a linear array. A sliding mechanical device was used to reconstruct the two-dimensional spatial variance information of targets. Spatial interpolation was applied to the two-dimensional temperature distribution information measured in real time to improve the resolution of the bean coleoptile locations. The temperature distributions above the vinyl mulch for five species of soybeans over a period of six days from the appearance of the cotyledon stage were analyzed. Results: During the experimental period, cases where bean cotyledons did and did not come into contact with the bottom of the vinyl mulch were both observed, and depended on the degree of growth of the bean cotyledons. Although the locations of bean cotyledons could be estimated through temperature distribution analyses in cases where they came into contact with the bottom of the vinyl mulch, this estimation showed somewhat large errors according to the time that had passed after the cotyledon stage. The detection results were similar for similar types of crops. Thus, this method could be applied to crops with similar growth patterns. According to the results of 360 experiments that were conducted (five species of bean ${\times}$ six days ${\times}$ four speed levels ${\times}$ three repetitions), the location detection performance had an accuracy of 36.9%, and the range of location errors was 0-4.9 cm (RMSE = 3.1 cm). During a period of 3-5 days after the cotyledon stage, the location detection performance had an accuracy of 59% (RMSE = 3.9 cm). Conclusions: In the present study, to fundamentally solve the problem of damage to beans from birds in the early stage after seeding, a working method was proposed in which punching is carried out after seeding, thereby breaking away from the existing method in which seeding is carried out after punching. Methods for the accurate detection of soybean growing locations were studied to allow punching to promote the continuous growth of soybeans that had reached the cotyledon stage. Through experiments using multiple IR sensors and a sliding mechanical device, it was found that the locations of the crop could be partially identified 3-5 days after reaching the cotyledon stage regardless of the kind of pulse crop. It can be concluded that additional studies of robust detection methods considering environmental factors and factors for crop growth are necessary.

The Nonlinear Motions of Cylinders(I) (주상체의 비선형 운동(I) -강제동요문제, 조파저항문제-)

  • H.Y. Lee;J.H. Hwang
    • Journal of the Society of Naval Architects of Korea
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    • v.29 no.4
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    • pp.114-131
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    • 1992
  • In the present work, a two-dimensional boundary-value problem for a large amplitude motion is treated as an initial-value problem by satisfying the exact body-boundary and nonlinear free-surface boundary conditions. The present nonlinear numerical scheme is similar to that described by Vinje and Brevig(1981) who utilized the Cauchy's theorem and assumed the periodicity in the horizontal coordinate. In the present thesis, however, the periodicity in the horizontal coordinate is not assumed. Thus the present method can treat more realistic problems, which allow radiating waves to infinities. In the present method of solution, the original infinite fluid domain, is divided into two subdomains ; ie the inner and outer subdomains which are a local nonlinear subdomain and the truncated infinite linear subdomain, respectively. By imposing an appropriate matching condition, the computation is carried out only in the inner domain which includes the body. Here we adopt the nonlinear scheme of Vinje & Brevig only in the inner domain and respresent the solution in the truncated infinite subdomains by distributing the time-dependent Green function on the matching boundaries. The matching condition is that the velocity potential and stream function are required to be continuous across the matching boundary. In the computations we used, if necessary, a regriding algorithm on the free surface which could give converged stable solutions successfully even for the breaking waves. In harmonic oscillation problem, each harmonic component and time-mean force are obtained by the Fourier transform of the computed forces in the time domain. The numerical calculations are made for the following problems. $\cdot$ Forced harmonic large-amplitude oscillation(${\omega}{\neq}0,\;U=0$) $\cdot$ Translation with a uniform speed(${\omega}=0,\;U{\neq}0$) The computed results are compared with available experimental data and other analytical results.

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A Study on Characteristics of Seed Germination of Native Plants for Revegetation on the Slope of River bank (하천 제방 비탈면 녹화용 자생 지피식물의 종자발아 특성에 관한 연구)

  • Cho, Yong Hyeon;Kim, Eun Su;Kang, Hee Kyoung;Cheong, Yong Moon
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.15 no.2
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    • pp.103-115
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    • 2012
  • To investigate the attributes of seed germination of the plants for greening of river bank slope, low-temperature treatment, chemical treatment, plant hormones treatment, and stratification were conducted using the seeds of 6 herbs growing naturally around river banks, such as Setaria glauca and faberii, Imperata cylindrica var. koenigii, Miscanthus sinensis, Pennisetum alopecuroides, Lespedeza cuneata and the seeds of 3 shrubs, such as Lespedeza bicolor., Rosa multiflora, Spiraea prunifolia for. simpliciflora. The findings are as follows. In case of herbs, Setaria glauca and faberii. have stone seeds. In the treatment with $H_2SO_4$, they were germinated through dormancy breaking, even though there were some differences depending on immersion time, and the germination rate of Setaria faberii was a bit higher than that of Setaria glauca. The germination rate of Imperata cylindrica var. koenigii was low in the treatment with $GA_3$, NAA, and the plant hormone, but the seed germination rate has improved and the germination rate of Miscanthus sinensis and Pennisetum alopecuroides showed the improved seed germination rate in low temperature treatment. In case of Lespedeza cuneata and bicolor, the leguminous plants, the treatment with $H_2SO_4$ was most effective for the improvement of seed germination and the decrease in germination time. Only Spiraea prunifolia for. simpliciflora, the rose among 3 woody plants showed the seed germination rate above 50% without any additional treatment. Thus, it was thought to be appropriate for greening. Rosa multiflora showed the attribute of germination in a dark condition at low temperature through stratification, despite its low germination rate. Based on the results as above, with respect to the greening using directly collected seeds, Miscanthus sinensis, Pennisetum alopecuroides, and Spiraea prunifolia for. simpliciflora are suitable for greening, because they do not need any additional treatment, and Lespedeza cuneata and bicolor are also suitable for greening because it is possible to improve the germination rate and reduce the germination time through the treatment on the seeds before sowing.

A STUDY OF WORKING EFFICIENCY AND FILE DEFORMATION OF GT ROTARY FILE IN CURVED CANALS (GT rotary file을 이용한 만곡 근관형성시 작업 효율 및 file 변형 발생에 관한 연구)

  • 신주희;백승호;배광식;임성삼;윤수한;김병현
    • Restorative Dentistry and Endodontics
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    • v.26 no.5
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    • pp.418-435
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    • 2001
  • Root canal preparation process is of utmost importance in successful treatment of root canal. Also, one of the most important purpose of the root canal preparation is to enlarge the root canal three dimensionally without changing the curvature of the root canal However as the curvature of the root canal increases, there are many difficulties involved in formation of optimum root canal. Therefore in order to solve the above mentioned problems, new developments in methods of root canal preparation and equipments for such purposes were made. Recently, vigorous studies about newly introduced engine-driven nickel-ti-tanium rotary file are conducted. As shown in research results to dates, it is well established that the use of nickel-titanium file is better suited for curved root canal than stainless steel file in maintaining the curvature or root canal and reducing the deformation of root canal. However it is also acknowledged that there are a few discrepancies in research results according to protocol, due to failure to remove variables in experiments. In addition, although it is recommended by the manufacturer that the GT rotary file should maintain a low rotational speed of 150~350rpm and 'light pressure' as light as not to break the lead of a pencil, academic studies about the vertical force which is not yet standardized are not sufficiently explored. Therefore, this research devised and utilized a special research equipment to standardize the appropriate range of vertical force for GT rotary file through experiments by breaking of the lead of a pencil as expressed by the manufacturer and to accurately measure factors involved through repeating and recreating the environment of root canal preparation. Forming nine experimental groups by varying the vertical forces (150g. 220g, 300g) and rpm (150rpm, 250rpm, 350rpm), the effects of changing vertical forces and rpm on working efficiency were measured in terms of time expended in root canal preparation by crown-down method using a transparent resin block with 35 degree curvature and GT rotary file (z-test). The following research using this special research equipment that involved nine experimental groups and varying the vertical force for root canal preparation from 300g which is within the normal vertical force range to 700g and 1000g which fall outside the normal rpm range. The results were as follows : 1. Analysis of the experiment results revealed that the time spent in root canal preparation decreased as the vertical forces and rpm increased (p<0.05). Also, the effects of rpm were greater than those of the vertical forces within the normal vertical force range ($\beta$-weight test). 2. Observation of the deformation of GT rotary file revealed that deformation increases in a direct correlation with the vertical force increase and in a reverse correlation with the rpm decrease. In the case of the vertical forces close to the normal range, the probability of GT rotary file deformation were quite different depending on the rpm changes. In the case of greater vertical forces, the occurrences of deformation of the file were more frequent regardless of the rpm changes. 3. Deformation and breakage of file were also commonly observed in the expended time measurement experiments and GT rotary file deformation experiments in which low speed rpm (150rpm) was used and at the curved portion of the resin block.

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Effect of Harvest Date after Heading. Storage Temperature and Duration on the Dormancy and Germination Percentage in Barley Cultivars (보리종자의 수확시기, 저장온도 및 기간에 따른 휴면성과 발아율에 관한 연구)

  • Chun, J.U.;Lee. E.S.;Park, M.W.;Cho, C.H.;Jeong, D.H.;Lee, H.J.
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.28 no.4
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    • pp.445-450
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    • 1983
  • To investigate the effect of harvest time after heading, storage temperature and duration on the dormancy and germination in barley cultivars, the kernels were collected at 5 day intervals from 20 days after heading until 35 days. The kernels were dried at 2$0^{\circ}C$ for 7 days and storaged in freezing chamber (-15$^{\circ}C$). The kernels germinated better at 15$^{\circ}C$ than at $25^{\circ}C$, and 1% $H_2O$$_2$ and 3 ppm GA$_3$ treatments gave much higher germination percentage than non-treatment; $H_2O$$_2$ and GA$_3$ treatments were good for promoting germination of immature harvested kernels. Germination rate index were significantly correlated with germination percentage under $25^{\circ}C$ and 15$^{\circ}C$ temperature conditions. Hangmi, Jogangbori and Muanbori had deep or slight dormancy at the different harvesting time, especially Dusan #8 had the deepest dormancy. The dormancy broke more rapidly under 3$0^{\circ}C$ than 2$0^{\circ}C$ storage conditions, so high temperature accelerated dormancy breaking. Those results showed that dormancy was various with the cultivars, harvesting time, storage temperature and storage duration.

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Development of deep learning algorithm for classification of disc cutter wear condition based on real-time measurement data (실시간 측정데이터 기반의 디스크커터 마모상태 판별 딥러닝 알고리즘 개발)

  • Ji Yun Lee;Byung Chul Yeo;Ho Young Jeong;Jung Joo Kim
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.26 no.3
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    • pp.281-301
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    • 2024
  • The power cable tunnels which are part of the underground transmission line project, are constructed using the shield TBM method. The disc cutter among the shield TBM components plays an important role in breaking rock mass. Efficient tunnel construction is possible only when appropriate replacement occurs as the wear limit is reached or damage such as uneven wear occurs. A study was conducted to determine the wear conditions of disc cutter using a deep learning algorithm based on real-time measurement data of wear and rotation speed. Based on the results of full-scaled tunnelling tests, it was confirmed that measurement data was obtained differently depending on the wear conditions of disc cutter. Using real-time measurement data, an algorithm was developed to determine disc cutter wear characteristics based on a convolutional neural network model. Distributional patterns of data can be learned through CNN filters, and the performance of the model that can classify uniform wear and uneven wear through these pattern features.