• Food Science and Preservation
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• v.30 no.5
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• pp.811-821
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• 2023

This study investigated the storability of onions according to manual and mechanical harvesting. Moreover, we simulated the onion-to-onion impact during the mechanical harvesting process and investigated the storability after artificially subjecting the onions to impact treatment. The onion harvesting methods included hand plucking + manual collection, digger + manual, and digger + mechanical collection. The maximum impact height during the mechanical harvesting process was 0.5 m. Immediately after harvesting, no significant difference in the bruise and wound rate among the harvesting methods was observed. Any increased bruise or wound rate because of mechanical harvesting was presumed to be influenced by soil conditions, such as the presence of gravel, and machine operation factors. Furthermore, the storability during the 8.5 months storage showed no significant difference according to the harvesting methods. In treatments by simulating the impacts during the mechanical harvesting process, the impact heights were 0.0 m (0.0 J), 0.25 m (0.86 J), 0.5 m (1.72 J), and 0.75 m (2.57 J), each performed once, and four times at the same position (3.43 J) and four times at different positions (3.43 J) at 0.25 m. Throughout all the treatments, there were no significant differences in the storability during the 8.5 months storage period.

• Journal of the Korean Society of Tobacco Science
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• v.15 no.1
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• pp.75-89
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• 1993

Effect of the amount of fertilizer, plant density, and harvesting time on the production of tobacco leaf protein and fresh biomass was investigated. Flue-cured tobacco(M tabacum, L., cv. NC 82) seedlings were transplanted in the field dressed 200kg N per ha at 1$\times$105, 3$\times$105, 5$\times$105, 7$\times$105 plants per ha, and were harvested at the time when 6 and 10 weeks after transplanting, respectively. Harvest at 10 weeks after transplanting increased greatly number of leaves per plant and fresh weight of a plant, Precentage of senescent leaf weight, but significantly decreased fresh weight of a leaf and total protein contents g-1 fresh weight of leaf and stalk over the amount obtained from the harvest at 6 weeks after transplanting. Also, fresh leaf numbers of a plant, fresh weight of a leaf and of a plant, and total protein contents g-1 fresh weight of biomass were more decreased, but percentage of senescent leaf weight were remarkably increased under higher plant density. Therefore, it was seemed that harvesting at 6 weeks after transplanting under 1$\times$105 plant density per ha is more effective for producing higher yield of biomass and protein per plant than 10 weeks harvesting with 7$\times$105 population per ha. A trend was observed that biomass and protein yields per ha are positively correlated with plant population. Biomass yield per ha was the greatest at 7$\times$105 density(80.5t), but the peak of protein yield was at the near of 5$\times$105 population(2454kg as total protein) per ha on the regression curve. It was assumed that if tobacco plants are transplanted under 5$\times$105 plant density at the mid of May, and thereafter harvest at 6 weeks repeatedly during the growing season, it is possible to harvest 2~3 times per year, and to yield more 6.024kg of protein and over 140me1ric tons of fresh biomass ha 1 year 1 statistically in the korea tobacco growing regions.

• Korean Journal of Medicinal Crop Science
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• v.13 no.1
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• pp.35-40
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• 2005

We analyzed six cultivars of Chinese Moutan, Paeonia suffruticosa Andrews, using HPLC for the investigation of appropriate root harvesting time and distributions of paeonol and paeoniflorin according to the seasonal changes. The contents of paeonol remained nearly constant at different harvesting times. However, the paeoniflorin contents have changed significantly during the harvesting time. These showed the increasing tendency in May, July and September. We compared the distribution of two compounds between two cultivars with different flower forms, Dan Feng and Wu Long Feng Sheng. The contents of paeonol were very low in the leaf and annual shoot. This tendency was not changed during five harvesting times. But the paeoniflorin existed abundantly in the leaf and root. The contents of paeoniflorin in the leaf were highest in May, and gradually decreased.

• Journal of Korean Society on Water Environment
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• v.31 no.3
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• pp.328-333
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• 2015

In this study, Mg-Sericite was used as a flocculant to harvest freshwater microalgae, Chlorella. vulgaris. Mg-Sericite separated successfully >95% of the C. vulgaris at the following optimal parameters: Mg/Si mol ratio 1.25 to 1.50, mixing time of 20 min and settling time of 20 min. The harvesting efficiency was pH dependent. The highest harvesting efficiency ($99{\pm}0.3%$) was obtained at Mg/Si mol ratio 1.5 and pH 9 to 11. These results indicated that a biopolymer, Mg-Sericite, can be a promising flocculant due to its high efficiency, low dose requirements, short mixing and settling times. This harvesting method is helpful to lower the production cost of algae for biodiesel.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.4
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• pp.491-497
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• 2015

Small-sized tuber of sweet potato (Ipomoea batatas Lam.) is more preferred by Korean consumers, because it is convenient to eat with hands, and can easily be steamed or roasted in small pan as a healthy snack for a small family. The present study was aimed to investigate the effect of high-density plantings and harvesting times on production of smallsized tuber (50~200 g). Four varieties ('Annobeny', 'Daeyumi', 'Shinzami', and 'Yeonhwangmi') were planted in 2-row zigzag high-density planting ($75{\times}30cm$, A; $75{\times}25cm$, B) and 1-row planting ($75{\times}25cm$, control) covered with black vinyl film on May 23th, 2014. Marketable yields and small-sized tuber yields were compared between 120- and 150-day harvesting. Vine length and fresh weight per plant were significantly decreased in 2-row planting A and B plots compared to the control at 120 days after planting. Weight of tuber per plant, mean weight of tuber and number of tuber per plant were significantly decreased in 120-day harvesting of A and B plots than in the control. Marketable yields per 10a were increased by 17% ($2.4ton{\cdot}10a^{-1}$) and 8% ($2.6ton{\cdot}10a^{-1}$) in 120-day harvesting of A and B plots compared to the control ($2.4ton{\cdot}10a^{-1}$), and those were largely increased by 29% ($4.0ton{\cdot}10a^{-1}$) and 26% ($3.9ton{\cdot}10a^{-1}$) in 150-day harvesting than in the control ($3.1ton{\cdot}10a^{-1}$). Proportions of small size tuber (50~200 g) were increased by about 65% in 150-day harvesting of A and B plots compared to the control (55.3%). Small-size tuber yield and marketable yield were highly increased in 150-day harvesting of 2-row zigzag high-density planting A ($75{\times}30cm$).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.425-428
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• 2017

This paper describes a full-wave rectifiers for energy harvesting circuit using a vibrational energy. The designed circuit is applied to the negative voltage converter with the body-bias technique using the Beta-multiplier so that the power efficiency is excellent even at the low voltage, and the comparator is designed as the bulk-driven type. The proposed circuit is designed with $0.35{\mu}m$ CMOS process, and The designed chip occupies $931{\mu}m{\times}785{\mu}m$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.11
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• pp.2457-2464
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• 2011

In this paper, a vibration energy harvesting circuit using a piezoelectric device is designed. MPPT(Maximum Power Point Tracking) control function is implemented using the electric power-voltage characteristic of a piezoelectric device to deliver the maximum power to load. The designed MPPT control circuit traces the maximum power point by periodically sampling the open circuit voltage of a full-wave rectifier circuit connected to the piezoelectric device output and delivers the maximum available power to load. The proposed vibration energy harvesting circuit is designed with $0.18{\mu}m$ CMOS process. Simulation results show that the maximum power efficiency of the designed circuit is 91%, and the chip area except pads is $700{\mu}m{\times}730{\mu}m$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.11
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• pp.2487-2494
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• 2012

In this paper, a thermal energy harvesting circuit with MPPT control is designed. MPPT(Maximum Power Point Tracking) control function is implemented using the linear relationship between the open-circuit voltage of a thermoelectric generator(TEG) and its MPP voltage. The designed MPPT control circuit traces the maximum power point by periodically sampling the open circuit voltage of a TEG, makes the reference voltages using sampled voltage and delivers the maximum available power to load. Simulation results show that the maximum power efficiency of the designed circuit is 94%. The proposed thermal energy harvesting circuit is designed with $0.35{\mu}m$ CMOS process, and the chip area except PAD is $1168.7{\mu}m{\times}541.3{\mu}m$.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.392-395
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• 2011

In this paper, a vibration energy harvesting circuit using the piezoelectric element has been designed. MPPT (maximum power point tracking control) control function has been implemented to deliver the maximum power to the load by using the electric power-voltage characteristic of the piezoelectric element. The designed MPPT circuit traces the maximum power point by sampling periodically the open circuit voltage of the full wave rectifier circuit and delivers the maximum available power to the load. The vibration energy harvesting circuit is designed with $0.18{\mu}m$ CMOS process. The maximum power efficiency is 91%, and the chip area except pads is $1,100{\mu}m{\times}730{\mu}m$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.11
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• pp.918-924
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• 2009

In this paper, we designed micro-structured electromagnetic transducers for energy harvesting and verified the performance of proposed transducers using finite element analysis software, COMSOL Multiphysics. To achieve higher energy transduce efficiency, around the magnetic core material, three-dimensional micro-coil structures with high number of turns are fabricated using semiconductor fabrication process technologies. To find relations between device size and energy transduce efficiency, generated electrical power values of seven different sizes of transducers ($3{\times}3\;mm^2$, $6{\times}6\;mm^2$, $9{\times}9\;mm^2$, $12{\times}12\;mm^2$, $15{\times}15\;mm^2$, $18{\times}18\;mm^2$, and $21{\times}21\;mm^2$) are analyzed on various magnetic flux density environment ranging from 0.84 T to 1.54 T and it showed that size of $15{\times}15\;mm^2$ device can generate $991.5\;{\mu}W$ at the 8 Hz of environmental kinetic energy. Compare to other electromagnetic energy harvesters, proposed system showed competitive performance in terms of power generation, operation bandwidth and size. Since proposed system can generate electric power at very low frequency of kinetic energy from typical life environment including walking and body movement, it is expected that proposed system can be effectively applied to various pervasive computing applications including power source of embodied medical equipment, power source of RFID sensors and etc. as an secondary power sources.