• Journal of Life Science
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• v.18 no.2
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• pp.143-147
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• 2008

This study estimated the mound litter biomass and the nutrient content of mound litter in the two study plots in Durokoppin Nature Reserve, Western Australia between 2004 and 2005. There were no significant differences in biomass of litter in individual mounds between the two study plots. Seven components of litter were found in the mounds. The nutrient concentrations were higher in the woodland than in the shrubland plot, although the differences were not statistically tested, and the total amount of each nutrient measured was generally greater in the woodland than in the shrubland plot. The aforementioned results show that D. tamminensis harvests various plant material according to biomass availability. The role of this termite takes on particular importance in view of the fact that Western Australian soils are notoriously impoverished in nutrients.

• Journal of the KSME
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• v.25 no.4
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• pp.312-319
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• 1985

유탁액(emulsion), 현탁액(suspension), 고분자용액(polymer solution) 및 고분자 용식물(polymer melt) 등의 유동에 대하여는 응력과 속도구배 사이에 선형적인 관계가 성립되지 않는다. 이런 유체들은 뉴우튼유체들의 경우와는 달리 단한번의 점성계수 측정만으로는 완전한 유변학 적(rheological) 특징을 파악할 수 없으므로 이들을 통털어서 비뉴우튼유체(non-Newtonian fluid )라고 한다. 이들의 응력과 속도구배 사이의 비선형적인 관계를 고찰하는 비뉴우튼유체역학은 최근에 빠르게 발전하고 있는 유체역학의 한 분야이며, 고분자 공정, 식품, 생물공학 및 유전등의 여러 산업부문에서 많은 관심의 대상이 되고 있다. 여기서는 뉴우튼유체에서 관찰될 수 없는 비뉴우튼유체의 독특한 유동 현상에 대한 이해를 증진시킴으로써, 비뉴우튼유체역학의 여러 문 제들을 취급하는데 필요한 기본지식을 제공하고자 한다.

• Korean Journal of Heritage: History & Science
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• v.57 no.1
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• pp.38-51
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• 2024

Although the bottle gourd (Lagenaria siceraria) is a crop with a cultivation history of about 10,000 years in the Old and New Worlds, archaeological considerations on the cultivation and use of bottle gourds on the Korean Peninsula are extremely rare. Accordingly, we reviewed previous reports on bottle gourds and examined the morphological characteristics of seeds and rind fragments from the Korean Peninsula. The investigation yielded several conclusions. First, bottle gourd cultivation likely began during the Bronze Age alongside the introduction of so-called southern crops. Evidence suggests that bottle gourd remains were more prevalent during the Three-Kingdoms period, indicating its significance as a crop during the historical era. Second, bottle gourd seeds from the Three-Kingdoms period exhibit characteristics of both African and Asian subspecies, showcasing a high level of morphological diversity. Third, rind thickness indicates that bottle gourds found at the Bongseon-ri site were of varieties with large fruits. Taken together, it is concluded that the bottle gourd was introduced to the Korean Peninsula during the Bronze Age, and people cultivated a range of bottle gourd varieties during the Three-Kingdoms period.

• Journal of the Korea Society for Simulation
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• v.31 no.1
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• pp.29-41
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• 2022

As one of the alternatives to solve the problem of unstable food supply and demand imbalance caused by abnormal climate change, the need for plant factories is increasing. Airflow in plant factory is recognized as one of important factor of plant which influence transpiration and heat transfer. On the other hand, Digital Twin (DT) is getting attention as a means of providing various services that are impossible only with the real system by replicating the real system in the virtual world. This study aimed to develop a digital twin model for airflow prediction that can predict airflow in various situations by applying the concept of digital twin to a plant factory in operation. To this end, first, the mathematical formalism of the digital twin model for airflow analysis in plant factories is presented, and based on this, the information necessary for airflow prediction modeling of a plant factory in operation is specified. Then, the shape of the plant factory is implemented in CAD and the DT model is developed by combining the computational fluid dynamics (CFD) components for airflow behavior analysis. Finally, the DT model for high-accuracy airflow prediction is completed through the validation of the model and the machine learning-based calibration process by comparing the simulation analysis result of the DT model with the actual airflow value collected from the plant factory.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.s02
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• pp.115-120
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• 1989

Universal characteristics of ginseng replanting problems appeared to be decrease in root yields due to root rot and inhibition of root growth. Incitants of ginseng replanting problems have not been clearly elucidated, however, it appeared to be a complex phenomenon with several pathogenic soil microorganisms and environmental changes in the soil due to decomposition of ginseng debris such as rootlets and shoots. Decomposition of ginseng debris may cause direct or indirect damage to the root. The effect of conventional fungicide on the control of the problems has not been recognized. However, it has been suggested that treatment with soil fumigants may solve the problems. Meanwhile paddy-rice and ginseng rotation system appeared to be the best way of solving the problems so far.

• The Microorganisms and Industry
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• v.14 no.3
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• pp.23-26
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• 1988

자연계에 있어서 질소는 대기중의 분자상질소를 비롯하여 초산, 암모니아와 같은 무기태질소, 단백질, 핵산 등의 유기태질소 등 다양한 형태로 존재하며 생물권내에서 흡수, 고정, 대사, 분해되는 등 다양한 순환을 거듭하고 있다. 대기중의 분자상질소는 Rhizobium, Azotobacter, Klebsielle, Clostridium, Blue-green algae 및 광합성세균 등에 의해 고장되어 암모니아의 형태로 환원된다. 한편 대부분의 식물들은 초산이나 암모니아 형태의 질소를 흡수 동화하여 핵산, 단백질을 만들고 이들 구성물은 사후 암모니아로 재분해 된다. 또한 동식물의 유체내지는 배설물들도 각기 분해되어 암모니아의 형태로 변화되는데 이와같은 일련의 질소순환(nitrogen cycle)은 초화세균, 탈질세균 내지는 질소고정균등 대부분의 미생물에 의해 크게 지배를 받고 있다.

• Journal of the Korea Society for Simulation
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• v.20 no.1
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• pp.97-105
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• 2011

In rivers and streams, biofilms are thin layers of greenish-brown slime attached to rocks, plants, and other surfaces. Biofilms play key roles in primary production and cycling of nutrients, water quality remediation, suspended sediment removal, and energy flow to higher trophic levels. In the present study, we developed a two-dimensional cellular automata model to simulate mixed biofilms of toxin-sensitive and toxin-producing species in hydrodynamic flow. The flow was generated by a stochastic process for uniform flow and by using the Navier-Stokes equation for non-uniform flow. Minimized local rules governing reproduction and mortality of the species were executed in the self-organizing processes to elucidate interactions between toxin-producing and toxin-sensitive species in competition over nutrients. We briefly discuss the morphology of the simulated biofilm under different flow conditions.

• Journal of Internet Computing and Services
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• v.16 no.1
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• pp.57-65
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• 2015

As information technology fusion is accelerated, the researches to improve the quality and productivity of crops inside a plant factory actively progress. Advanced growth environment management technology that can provide thermal environment and air flow suited to the growth of crops and considering the characteristics inside a facility is necessary to maximize productivity inside a plant factory. Currently running plant factories are designed to rely on experience or personal judgment; hence, design and operation technology specific to plant factories are not established, inherently producing problems such as uneven crop production due to the deviation of temperature and air flow and additional increases in energy consumption after prolonged cultivation. The optimization process has to be set up in advance for the arrangement of air flow devices and operation technology using computational fluid dynamics (CFD) during the design stage of a facility for plant factories to resolve the problems. In this study, the optimum arrangement and air flow of air circulation fans were investigated to save energy while minimizing temperature deviation at each point inside a plant factory using CFD. The condition for simulation was categorized into a total of 12 types according to installation location, quantity, and air flow changes in air circulation fans. Also, the variables of boundary conditions for simulation were set in the same level. The analysis results for each case showed that an average temperature of 296.33K matching with a set temperature and average air flow velocity of 0.51m/s suiting plant growth were well-maintained under Case 4 condition wherein two sets of air circulation fans were installed at the upper part of plant cultivation beds. Further, control of air circulation fan set under Case D yielded the most excellent results from Case D-3 conditions wherein air velocity at the outlet was adjusted to 2.9m/s.

• Clean Technology
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• v.21 no.2
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• pp.90-95
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• 2015

Digital microfluidic electroporation system was used for the transformation of microalgae and we have obtained higher transformation efficiency and viability than that of conventional method. Key parameters of electroporation such as pulse voltage, number, and duration time were systematically investigated for two different microalgal strains with and without cell wall. We have found that cell wall does not always have negative effects on the gene transformation of microalgae. Parallel processing of proposed digital microfluidic electroporation was demonstrated together with on chip culture of microalgae.

• The Korean Journal of Quaternary Research
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• v.25 no.1
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• pp.31-39
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• 2011

Phytolith of soil in earthenware buried in the wooden chamber tombs at the archaeological site in Hwangseong-dong, Gyeongju along Hyeongsan River are analyzed. The study area has adjoined the seat of government during approximately thousand years in Shilla Dynasty and can be regarded as being closely related to the agricultural activities using the floodplains of Hyeongsan River. By the analytical results, Phragmites, Paniceae and Andropogoneae as well as Oryza sativa are found in the lower horizons, indicating the agricultural activities in the nearby areas. It is suggested for understanding the use of earthenware that the comparisons of buried soils in the site and soils in the earthenware and analysis on the macro plant fossils of soil in the earthenware are needed.