• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.23 no.2
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• pp.83-87
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• 2017

This study was conducted to determine types of oxygen transmission rate (OTR) films suitable for modified atmosphere (MA) storage treatment of strawberries (cv. 'Maehyang') for export and examination related changes in quality of strawberries during simulated shipping distribution conditions ($2^{\circ}C$ for $10days{\sim}8^{\circ}C$ for 11 days). Strawberries were packed by 1,300, 10,000, 20,000, and $30,000cc/m^2{\cdot}day{\cdot}atm$ OTR films for MA storage treatment and perforated film as the control for MAP. Fresh weight loss rate was less than 0.5% in OTR films except for the perforated film. Carbon dioxide and oxygen content in packages prevailed in permissible range for strawberries under recommended CA/MA conditions (i.e., $CO_2$: 15~20%, $O_2$: 5~10%) at 10,000 cc, 20,000 cc, and 30,000 cc OTR films. Ethylene content in OTR films did not reveal significant differences during storage. The 1,300 cc OTR film revealed highest off-flavor and lowest fungal incidence rate by sensory evaluation. The firmness, soluble solids, and visual quality were preserved the highest at 10,000 cc OTR film. In conclusion, 10,000 cc OTR film preserved the highest quality and extended shelf-life by 13 days if compared with conventional distribution conditions.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.3
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• pp.209-218
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• 2011

The present study proposes a new estimation relationship for the transmission rate of the steel breakwater which is expected to make up for the weakness points in existing hard solution for shore protection. The steel breakwater consists of the wave dissipator of the dual horizontal plates, the supporting columns and their foundations, and thus its respective designs should also be conducted one by one. Furthermore, the breakwater has to ensure both functions of shore protection and structure stabilization. The study produced experimental data for the stability and safety investigation of the steel breakwater. The forces acting on the steel breakwater were classified into two categories, one is vertical up and down loads for the pile resistance and the other was maximum difference of the vertical load acting on horizontally different position for the torsion. The study applied the stability force produced by the summation of maximum pressure at each point and the safety force acting on each point simultaneously. The regular wave corresponding to the significant wave was utilized for measuring wave pressure and force. The study showed the method for the proper position of submerged upper plate by considering occurrence frequency of tide level. The design process finally determined by trial and error is proposed in the present study.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.2
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• pp.193-204
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• 1998

The single crystal of the $LiTaO_3$has large electro-optic effects, so it is applied to optical switch, acousto-optic deflector, and optical memory device as hologram using photorefractive effect. In this study, optic-grade undoped $LiTaO_3$and Fe:LiTaO$LiTaO_3$single crystals were grown by the Czochralski method and optical transmission and absorption spectrums were measured in the wavelength of UV-VIS range. The curie temperature was determined with DSC and by measuring capacitance for the grown undoped crystal and ceramic powder samples of various Li/Ta ratio. In case of having a 48.6 mol% $Li_2O$ as a starting Li/Ta ratio, the results of concentration variations were below 0.01 mol% $Li_2O$ all over the crystal, so it was confirmed that $LiTaO_3$single crystals were grown under congruent melting composition having optical homogeneity. The curie temperature of the Fe:$LiTaO_3$crystal was increased with increased with increased doped Fe concentrations;by the ratio of $7.5^{\circ}C$ increase per Fe 0.1 wt%. Also, the optical transmittance was about 78 %, which was sufficient for optical device.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.02a
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• pp.457-463
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• 2002

이 연구는 x-선 투과영상을 이용하여 홍삼의 내공을 검출하기 위하여 수행되었다. 이를 위하여 x-선관에 조사되는 x-ray 양의 차이에 따른 위치별 밝기 값 차이를 보정하고 내공 검출에 적합한 영상처리 알고리즘을 개발하였다. 주요연구 결과를 요약하면 다음과 같다. 1) x-선관에 조사되는 x-ray양은 중심에서 가장자리로 갈수록 감소하며, 이것은 위치에 따른 gray 값의 분포가 달라지게 되는 원인이 되었다. 2) 홍삼을 2치화 하기 위해서는 동일한 x-선 조사강도에서 입력된 원 영상에서 빈 영상을 뺀 감산 영상을 만들어 줌으로써 가능하였다. 3) 조사강도 별 감산영상처리 결과 36kV/4.15mA와 39kV/4.15mA에서는 조사량이 많아서 홈삼 지근 부분의 영상이 손실되는 경우가 발생하였다. 4) 내공 검출을 위해서는 정상부분과 내공부분의 자기 값 차이를 크게 하는 전처리 영상을 만들 필요가 있었고, multiple 감산영상에서 뚜렷한 골짜기가 나타났으나 주근의 내공부분의 밝기값 보다 지근의 정상부분의 자기 값이 더 낮게 나타나 이를 보정하기 위하여 홍삼 위치에 따라 부분 보정된 알고리즘을 개발하였다. 5) x-선관의 놓인 위치에 따라서 내공판정시험 결과 중심에 있을 때에 비해 가장자리에 있을 때는 영상이 일부 손실되었으며, 중심 위치에서 서로 다른 굵기의 홍삼에 대해서는 모두 양호한 결과가 나타났다. 6) 완전한 홈삼으로 내공판정시험 결과 내공주위의 정상부분가지도 일부 내공으로 잘못 검출되었으나 이것을 재차 line profile에 의해 한 라인씩 문턱 값을 설정하여 내공만을 정확하게 판정하는 알고리즘을 개발하였다.양체의 접종작업은 모든 배양실이 인력에 의존하였으며, 배양체를 배지와 분리하여 불필요한 부분을 제거하고 배양작물에 따라 생육정도를 2~3등급으로 구분하여 배양용기의 배지 위에 치상하는 과정으로 수행되었으며, 작업능률은 호접란의 경우 배양병에 25본을 접종하는데 시간당 6병, 심비디움은 원형 플라스크에 25본을 접종하는데 시간당 10병 정도였다. 바. 식물체의 대량증식에 사용되는 플라스크, 배양병, PE용기 등 배양용기의 세척작업은 농원의 1개배양실에서 간이식 세척기, 이 외의 9개배양실은 모두 물에 담겨 두었다가 세제와 브러쉬 등을 사용하여 인력으로 세척하고 있어 생력화 기술개발이 요구되었다.도가 빠를수록 건조속도가 빨라졌으며, 건조에너지도 1,334kcal/kg.water로 비슷하게 소요되었다. 마. 시험구와 대비구의 건감률은 시험구에서 1.08~1.36w.b./h로 나타나 대비구보다 약 9.9~18.3%가 높게 나타났고, 건조에너지는 10.2~14.6%가 절감되었다. 발아율은 열풍온도가 낮을수록 높게 나타났고 시험구가 대비구보다 발아율이 낮게 나타났으며, 동할률 증가량도 원적외선.열풍 복합건조방법이 높게 나타나 이것은 곡물 표면에 원적외선 방사에의한 복사열이 전달되어 열장해를 받았기 때문으로 판단되며, 금후 더 연구하여 적정 열풍온도 및 방사체 크기를 구명해야 할 것이다.으로 보여진다 따라서 옻나무 유래 F는 포유동물의 생식기능에 중요하게 작용하는 것으로 사료된다.된다.정량 분석한 결과이다. 시편의 조성은 33.6 at% U, 66.4 at% O의 결과를 얻었다. 산화물 핵연료의 표면 관찰 및 정량 분석 시험시 시편 표면을 전도성

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.3
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• pp.39-47
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• 2022

In this paper, we proposed a thickness measurement method of concrete slab using GPR, and the verification of the suggested algorithm was carried out through real-scale experiment. The thickness measurement algorithm developed in this study is to set the relative dielectric constant based on the unique shape of parabola, and time series data can be converted to thickness information. GPR scanning were conducted in four types of slab structure for noise reduction, including finishing mortar, autoclaved lightweight concrete, and noise damping layer. The thickness obtained by GPR was compared with Boring data, and the average error was 1.95 mm. In order to investigate the effect of finishing materials on the slab, additional three types of finishing materials were placed, and the following average error was 1.70 mm. In addition, sampling interval from device, the effect of radius on the shape of parabola, and Boring error were comprehensively discussed. Based on the experimental verification, GPR scanning and the suggested algorithm have a great potential that they can be applied to the thickness measurement of finishing mortar from concrete slab with high accuracy.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.2
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• pp.111-117
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• 2003

We collected the domestic and foreign half-mirror coating lens for sunglasses. Their reflectance is measured using Spectrophotometer in order to analysis their optical property and the result which is calculated using Macleod program was compared with measured reflectance. In addition, we designed the new half-mirror coating lens with gold color using TiN material and investigated the optical property of the new half-mirror coating lens. The results obtained from analysis of half-mirror coating lenses are as follow : Two-tone half-mirror coating with silver color is fabricated with [air|$SiO_2$(or $Al_2O_3$)|Cr|glass]. The role of $SiO_2$(or $Al_2O_3$) on Cr improve the hardness of the lens and the thickness of the $Al_2O_3$ with 10 nm is good to show the lens silver color. Incase of color half-mirror coating lens. Blue system is designed by [air|$SiO_2$(66.3)|$TiO_2$(129.0)|$SiO_2$(62.9)|$SiO_2$(26.0)|$TiO_2$(120.3)|$SiO_2$(9.1)|glass], gold system [air|$SiO_2$(60.6)|$TiO_2$(86.2)|$SiO_2$(13.5)|$TiO_2$(86.8)|$SiO_2$(214.38)|glass], green system[air|$SiO_2$(74.3)|$TiO_2$(75.8)|$SiO_2$(44.3)|$TiO_2$(11.6)|$SiO_2$(160.8)|$TiO_2$(12.9)|$SiO_2$(183.3)|$TiO_2$(143.8)|glass], silver system[air|$SiO_2$(21.2)|$TiO_2$(49.7)|$SiO_2$(149.3)|glass]. White half-mirror coating lens has [air|$SiO_2$(17 nm)|$TiO_2$(43 nm)(or $ZrO_2$)|$SiO_2$(87 nm)|polysiloxane($4.46{\mu}m$|glass or CR-19]. It has half-mirror coaling lens which has about 19% reflectance and about 80% transmittance in the range of visible light(400~700nm). we designed the new half-mirror coating lens with gold color, the (x, y) value of the CIE is almost similar to the CIE value of [air|$SiO_2$(170 nm)|TiN(15 nm)|glass].

• Horticultural Science & Technology
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• v.32 no.5
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• pp.655-665
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• 2014

The effect of modified atmosphere packaging (MAP) on kohlrabi (Brassica olerace L. gongulodes group)'s quality and antioxidant molecule during storage was examined to determine the optimal film package for maintaining freshness. To extend shelf life, MAP was tested using PE $50{\mu}m$ and oriented polypropylene (OPP) films with oxygen transmission rate (OTR) at 3,000, 10,000, $15,000mL/m^2/day/atm$. The OPP film packaging with modified oxygen transmission rate showed a delay in a weight loss and extended storage period. The package with OTR 3000 attained the desired gas composition of $O_2$ 3.2-6.7 kPa and $CO_2$ 13.1-19.8 kPa, in storage at room temperature. Kohlrabi stored in this package showed the lowest weight loss and the highest visual quality. Deterioration and off-odor were developed more rapidly in PE $50{\mu}m$ towards the end of the storage at room temperature. However, there are no differences among OTR films in visual quality and off-odor until 60 days at cold storage. Vitamin C content of kohlrabi was reduced rapidly in OTR 15000 with high transmission rate and showed less loss in PE $50{\mu}m$ and OTR 3000 in both room temperatures and cold storage. Results revealed that an OPP film with OTR 3000 extended the shelf life of kohlrabi in storage with maintained quality and vitamin C.

• Food Science and Preservation
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• v.24 no.3
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• pp.351-360
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• 2017

We have studied the technology to extend the storage period of 'Seolhyang' strawberries using modified atmosphere package (MAP) and ethyl pyruvate (EP) treatment for domestic distribution and export. The selected ripe strawberries harvested on December 28, 2016 at the Sancheong farmhouse were transported to the laboratory for 2 h and tested. After a day's precooling at $4^{\circ}C$, the strawberries were divided into seven experimental groups. These groups were control, active MAP using low density polyethylene (LDPE), active MAP using polyamide (PA), active MAP using PA with EP treatment, passive MAP using LDPE, passive MAP using PA and passive MAP using PA with EP treatment. Quality analysis was carried out every 4 days during the storage period of 16 days. During the storage period of 16 days, MAP decreased from 3.5% to less than 1.1% in weight loss ratio compared with control, and decreased from 36% to less than 7% in fungal incidence. In the case of fungi in the EP treatment group, hyphae did not grow on the outside of the strawberry but grew to the inside. This tendency was similar to that in the low oxygen and high carbon dioxide environment of the MAP, the mycelium of the fungus did not grow outside of the strawberry. Fungi are the biggest problem in the distribution and export of strawberries, and these results suggest that MAP alone could inhibit mold and increase shelf life.

• Journal of the Korea Organic Resources Recycling Association
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• v.23 no.4
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• pp.52-62
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• 2015

This study estimated the contribution rates of inlet air flow, moisture content, air-filled porosity and particle size on the total pressure drop for the sawdust used as the bulking agent in the composting. The statistical model for pressure drop including the affecting factors was proposed.($R^2=0.998{\sim}0.950$) While the laminar air flow(v) and particle size(SIZE*v) had the positive relations to the total pressure drop, the turbulent air flow($v^2$), moisture content(MC*v) and air-filled porosity(AFP*v) had the negative relations. Total pressure drop sharply increased with increasing of the inlet air flow. And the most significant factors affecting to total pressure drop were the particle size(SIZE*v) as positive factor and air-filled porosity(AFP*v) as negative factor. The contribution rate to total pressure drop by the particle size(SIZE*v) was continuously increased with increasing of the inlet air flow, but the contribution rate by air-filled porosity(AFP*v) was decreased. And total pressure drop was little changed even though the increasing of moisture content above the range of dry moisture content 0.25. The contribution rates of affecting factors had the different tendencies with increasing of the moisture content, especially in the negative factors as air-filled porosity(AFP*v) and moisture content(MC*v). For effective composting process, it is preferable to select the sawdust with higher air-filled porosity as bulking agent to enhance the air permeability.

• Journal of Korean Ophthalmic Optics Society
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• v.4 no.2
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• pp.45-49
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• 1999

The second harmonic, wavelength is 397nm, of the continuous wave diode laser, whose maximum power is 35mW, was generated in $LiIO_3$ crystals in a ring enhancement cavity. 5mm- and 10mm-long crystals cut $43.21^{\circ}$ for optic axis were used in this experiment. Both surfaces of those were anti-reflection coated for 794nm. In case the crystal was inserted into the cavity, the condition of separation between two concave mirrors for the optimum mode matching was found. The conversion efficiency of second harmonic generation was increased by the resonant enhancement of pumping power in the ring enhancement cavity, and the frequency of diode laser was locked to that of the counter-propagation mode generated from the surface of crystal. When the pumping power was 28 mW, the infrared buildup factor was about 45 without the crystal, and 14 with the crystal due to the transmission loss of crystal. The maximum second harmonic powers of $1.5{\mu}W$ and $6.6{\mu}W$ were obtained, and corresponding conversion efficiencies were $(6.584{\pm}0.56){\times}10^{-3}$%, $2.6{\pm}0.21){\times}10%{-2}$% in 5mm- and 10mm-long $LiIO_3$, respectively.