• Journal of Bio-Environment Control
• /
• v.19 no.4
• /
• pp.366-371
• /
• 2010

A study was conducted to examine the effect of precooling (2, 4, or $8^{\circ}C$) and storage (4, 8, or $10^{\circ}C$) temperatures on the storage life of 'Maehyang' and 'Soogyeong' strawberries for export. Fruits at a 70% ripe stage were harvested from a commercial greenhouse in Jinju on March 16, 2010. Fruits were precooled by a forced draft cooling for 3 hours, transported for about 30 minutes to a lab., and then stored. For precooling, small precoolers set in the farm were used. During storage, fruits were examined for their changes in weight, hardness, color (hunter value), soluble solid content, incidence of gray mold (Botrytis cinerea), and marketability at a two days interval from March 16 to March 30. In both cultivars, hardness, sugar content, and hunter value were higher in 'Soogyeong' than 'Maehyang'. The greatest hardness and soluble solid content were obtained after storage at $4^{\circ}C$ in both cultivars. As the ripening stage progressed, hardness and soluble solid content decreased. Also, fresh weight decreased during storage at all temperatures. Gray mold was the greatest at $10^{\circ}C$ storage temperature. The results indicate that effectiveness for keeping the freshness was best achieved by precooling at $2^{\circ}C$ and storage at $4^{\circ}C$ in both cultivars.

• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.921-932
• /
• 2010

Metropolitan railway headway is calculated and decided by external conditions such as appropriate level of service and competitiveness rather than passenger demand for the peak time which is based on transport passenger capability of train. On contrast of inter-city urban railways, train time intervals of sub-urban metropolitan railway were fixed more than 20 mins in the peak time which results in low level of convenience. Big gap of headway brings a vicious circle of deteriorating competitiveness and decreasing the number of customers. Also this time gap of train interval results in stagnation of passenger demand, and makes it difficult to reduce headway. This thesis is a basic research to identify headway problems and their solutions of metropolitan railway. This thesis suggests passenger demand and the calculated standard for setting the headway, and reviews the level of passenger crowdedness, the numbers of coach for each train and time-competitiveness. At the last, thesis suggests the need for making headway by means of train services throughout benefit & cost analysis. And it also recommends the improved calculating method of setting up headway considering the different train headway standards by regional situation, flexibility in the number of coaches for a train, government policy to activate railway business and the need for setting up the standard for train service level.

• The Korean Journal of Mycology
• /
• v.3 no.2
• /
• pp.19-23
• /
• 1975

A study on the variation of the air temperature in the pine mushroom box containing dry ice for the preservation of the freshness of the pine mushroom, Tricholoma matsutake (Ito et Imai) Sing. produced in Korea was made in Seoul, Korea during the period of August 1 to 30, 1975. A safe shipment of 5 kg (net weight) of fresh mushrooms with freshness preserved for 24 hours in August required the placement of 4.5 kg of dry ice-a half in the upper portion and the other half in the middle portion-in an airtight container (mushroom box). The container used for the shipment test, made of 3mm-thick double-layer cardboard, was of the dimensions : $0.33{\times}0.4{\times}0.5=0.066(m^3)$. As the temperature fell, decreased amounts of dry ice were needed : 3 to 2 kg in September and 1.5 to 0.3 kg in October. With this preservation method, large quantities of fresh mushrooms were exported to Tokyo ana Osaka, Japan without damage in the process of transportation.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.08a
• /
• pp.264-265
• /
• 2010

최근, nanorod나 nanowire와 같은 1차원의 나노구조가 나노디바이스로 각광을 받고 있다. [1] 특히 InN는 3족 질화물 반도체 중 가장 작은 밴드갭 에너지와 뛰어난 수송 특성을 가지고 있어 나노디바이스로의 응용에 적합한 물질이다. [2] 그러나 InN는 큰 평형증기압을 가지므로 쉽게 인듐과 질소로 분해되는 특성이 있어 나노구조로의 성장이 쉽지 않음이 알려져 있다. [3] 최근 연구결과에 따르면, InN 나노구조는 금속 catalyst를 사용한 방법이나, 기판 위 패턴을 이용하여 성장하는 방법, 염소를 사용한 방법이 널리 쓰이고 있다. [4,5,6] 그러나 이 방법들은 의도치 않은 불순물의 원인이 되거나 다른 추가적인 과정을 필요로 한다는 문제점도 일부 가지고 있다. 본 연구에서는 catalyst-free 유기 금속 화학 증착법 (MOCVD)를 이용하여 $Al_2O_3$ (0001)면 위에 InN nanostructure를 성장하였다. InN nanostructure 성장 시 트리메틸인듐(TMIn)과 암모니아($NH_3$) 를 전구체로 사용하였으며, 캐리어 가스로는 질소를 사용하였다. 또한 모든 샘플의 성장시간은 60분으로 고정하였으나, 성장 시 온도의 의존성을 보기 위해 $680-710^{\circ}C$ 의 온도범위에서 성장을 진행하였다. 그 결과 InN는 본 실험에서 적용된 성장온도범위 내에서 온도가 증가함에 따라 초기에는 columnar구조로 성장된 박막의 형태에서 wall이 배열된 형태로 변화하며 결국 $710^{\circ}C$ 의 온도에서 nanorod로 성장하게 된다. 성장된 InN의 나노구조는 X-선 회절 측정법, 주사 전자 현미경 그리고 투과 전자 현미경을 이용하여 각각의 구조적 특성을 분석하였다. X-선 회절 측정법과 주사 전자 현미경을 통한 분석결과에서는 이들 nanorods가 대부분 c 방향으로 수직하게 정렬되어 있음을 확인 할 수 있었다. 또한, $690^{\circ}C$ 에서 60분간 성장된 InN의 wall 구조의 두께는 200 nm, 길이는 $2-2.5\;{\mu}m$로 관찰되었으며, $710^{\circ}C$에서 60분간 성장된 InN nanorod의 지름은 150 nm, 길이는 $3\;{\mu}m$ 정도로 관찰되었다. 이를 통하여 볼 때 성장 온도가 InN의 나노구조 형성 시 표면의 모폴로지변화에 중요한 변수로 작용함을 알 수 있다. 본 발표에서는 이러한 표면 형상 및 구조 변화가 성장온도에 따른 관계성을 가짐을 InN의 분해와 성장의 경쟁적인 관계에 의해 논의할 것이다.

• Korean Journal of Veterinary Research
• /
• v.36 no.3
• /
• pp.665-680
• /
• 1996

Bovine Pneumonic Pasteurellosis는 수송열(輸送熱)로 일반적으로 알려져 있는 질병으로서, 여러가지 요인의 복합적(複合的)인 작용에 의해 발병하는 것으로 알려져 있으나, Pasteurella haemolytica A1이 가장 주요(主要)한 인자(因子)로 밝혀져 있다. P haemolytica A1은 leukotoxin(LKT), lipopolysaccharide(LPS), capsular polysaccharide 등 여러가지의 병원성인자(病原性因子)을 생성한다. 이들 인자중 LKT가 가장 중요한 병원성인자로 밝혀져 있다. 이에 본 실험은 P haemolytical A1의 LKT 유전자를 Bacillus subtilis에서 발현(發現)시킴으로서 LPS에 오염(汚染)되지 않은 LKT을 대량으로 생산할 목적으로 실시되었다. 실험의 첫 단계(段階)로서 pLKT52 plasmid을 Sau3 A1의 제한효소을 이용하여 부분소화(部分消化)시킨 후 이 부분 소화(消化)된 유전자들로부터 3~5kb 크기의 유전자들을 순수분리하여 pUC18와 결합시킨 후 E coli NM522에 형질전환(形質轉換)시켰다. 이때 형질전환된 균주들은 LKT에 대한 단크론 항체인 MAb601을 이용하여 colony blot 법에 의해서 LKT 유전자 보유 및 발현여부(發現與否)을 조사하였다. 이들 양성 clone들은 제한효소분석(制限酵素分析), 염기서열분석(鹽基序列分析) 및 Western blot 등에 의해서 재확인(再確認)하였다. 총 9개의 양성 clone중 위의 방법에 의해서 한 clone을 선택(選擇)하여 lktCA insert를 재분리하여 shuttle vector에 subcloning 하였다. Subcloning된 LKT 유전자들은 shuttle vector의 종류(種類)(pHPS9, p602/20, pHPS9-Sac)와 각기(各其) 다른 종류(種類)의 B subtilis(spoO12A, BR121, WB3O, Raj1105) 숙주내(宿主內)에서 발현정도를 Western blot 법에 의해서 비교(比較)하였다. 이때 최적발현조건(最適發現條件)은 p602/20와 pBL1의 dual plasmid system을 이용하여 B subtilis spoO12A에서 2시간동안 IPTG로 발현을 유도(誘導)하는 것이었다. B subtilis에서 발현된 LKT을 visual 법과 neutral red uptake 법을 이용하여 소 폐포(肺胞) 대식구(大食求)에 대한 biological activity를 확인하였다. 발현된 LKT에 대한 LPS 오염은 LKT을 SDS-PAGE 후 silver stain에 의해서 확인하였다. 본 실험을 통해서 볼 때에 lktCA 유전자를 보유(保有)하고 있는 p602/20는 B subtilis에서 매우 불안정(不安定)하였고, 발현된 LKT는 세균자체(細菌自體)에서 생성되는 protease들에 의해서 파괴(破壞)됨으로서 농도(濃度)가 매우 낮았다. 이러한 문제점들은 다음 단계(段階)의 실험에서 해결되어야할 문제들이다.

• Journal of Korean Society of Transportation
• /
• v.21 no.2
• /
• pp.71-82
• /
• 2003

The shortest path problems(SPP) are critical issues in the military logistics such as the simulation of the War-Game. However, the existing SPP has two major drawbacks, one is its accuracy of solution and the other is for only one solution with focused on just link cost in the military transportation planning models. In addition, very few previous studies have been examined for the multi-shortest path problems without considering link capacity reflecting the military characteristics. In order to overcome these drawbacks, it is necessary to apply the multi-shortest paths algorithm reflecting un-expected military incidents. This study examines the multi-shortest paths in the real networks using Shier algorithm. The network contains both military link capacity and time-based cost. Also, the modes are defined as a platoon(group) rather than unit which is used in most of previous studies in the military logistics. To verify the algorithm applied in this study. the comparative analysis was performed with various sizes and routes of network which compares with Dijkstra algorithm. The major findings of this study are as follows ; 1) Regarding the unique characteristics of the military transportation plan, Shier algorithm, which is applied to this study, is more realistic than Dijkstra algorithm. Also, the time based concept is more applicable than the distance based model in the military logistics. 2) Based on the results from the various simulations of this study the capacity-constraint sections appeared in each scenarios. As a consequence, the alternatives are necessary such as measures for vulnerable area, improvement of vehicle(mode), and reflection of separated-marching column in the military manuals. Finally. the limits and future research directions are discussed : 1) It is very hard to compare the results found in this study. which is used in the real network and the previous studies which is used in arbitrary network. 2) In order to reflect the real military situations such as heavy tanks and heavy equipment vehicles. the other constraints such as the safety load of bridges and/or the height of tunnels should be considered for the future studies.

• Journal of Animal Environmental Science
• /
• v.17 no.2
• /
• pp.107-114
• /
• 2011

This study was designed to determine the effect of season and split-sex feeding on performance, stress and carcass quality of finishing pigs. Two hundred and seventy cross-bred finishing pigs $(82.1{\pm}0.82kg)$ were randomly divided into six groups in 2 seasons (summer and winter) ${\times}$ 3 split-sex feeding (female only, castrated male and mixed) factorial arrangement of treatments. In winter, feed intake and weight gain of finishing pigs were better than summer (p<0.05). Split-sex feeding was affected the feed conversion, feed conversion of finishing pigs were superior in winter and mixed groups. Plasma concentrations of cortisol as a stress indicators was greater in the mixed groups vs female only and castrated male groups. There were no interactions between the season and split-sex feeding in their effects on these blood variables. The season was affected the carcass characteristics and PSE incidence of the finishing pigs, PSE incidence was low in winter and mixed groups. Meat quality did not show any significant difference due to the difference of season and split-sex feeding of finishing pigs. There was no significant difference in the pH, drip loss and meat color of pork loin between the season and split-sex feeding of finishing pigs. In conclusion, the results of this study suggest that we need more precise on-farm management practice in summer and application of split-sex feeding skills to reduce the stress and improve welfare status of finishing pigs.

• Journal of Veterinary Clinics
• /
• v.22 no.3
• /
• pp.175-180
• /
• 2005

The purpose of this study is to investigate the effects of formulation variables on the release of cefadroxil form chitosan beads, to optimize the preparation of chitosan beads loaded with the drug for controlled release, and to evaluate the drug release form chitosan beads in dogs. Chitosan beads were prepared with tripolyphosphate (TPP) by ionic cross-linking and those sizes were less than 1 mm in diameter. The release behaviour of cefadroxil was affected various factors. As pH of TPP solutions decreased, the entrapment efficiency of cefadroxil increased, whereas the release of cefadroxil decreased. The release rate of cefadroxil form chitosan beads decreaed with the increased TPP solution concentration. When cross-linking time increased, the release of the drug from chitosan beads decreased. The cefadroxil loaded beads were implanted to 4 mixed breed dogs. The concentration of cefadroxil in sera due to chitosan beads implanted with 50 mg/kg body weight of beads was sustained more than 1 ug/ml for the whole 7 days period. Therefore, the cefadroxil loaded beads can be used successfully in pyoderma of dogs. These results indicate that chitosan beads may become a potential delivery system to control the release of drug.

• Korean Journal of Materials Research
• /
• v.8 no.5
• /
• pp.457-463
• /
• 1998

New neutron shielding materials, KNS-201, KNS-301 and KNS-601 have been fabricated to be used for radioactive material shipping and storage cask. The base materials are a modified and a hydrogenated bisphenol- A type and novolac type epoxy resin, and aluminium hydroxide and boron carbide are added. These shielding materials offer good fluidity at processing, which makes it possible to form this resin shield into complicated geometric shapes such as radioactive material shipping and storage cask. Several measurements were made for the shielding materials to evaluate the thermal and mechanical properties and radiation resistance. The properties of the shielding materials are as follows: onset temperatures 2S7~28$0^{\circ}C$, thermal conductivities 0.9S~1.14W/m. K, thermal expansion coefficients 0.77~1.26x$10_{-6}{\circ}C_{-1}$, combustion characteristics < 80$0^{\circ}C$, ATB(average time of burning) < 5sec, AEB(average extent of burning) < 5mm, tensile strengths 2.5~3.2kg/$\textrm{mm}^2$, compressive strengths 13.2~1S.2kg/$\textrm{mm}^2$, flexural strengths 5.2 -6.4kg/$\textrm{mm}^2$. In general, the concerned properties of KNS-201, KNS-301 and KNS-601 were revealed to be better than those of NS-4- FR. foreign neutron shielding material. It is also observed that the radiation resistance of KNS- 601 was better than those of KNS-201 and KNS-301.

• Journal of Korea Port Economic Association
• /
• v.25 no.4
• /
• pp.1-20
• /
• 2009

Green logistics is regarded as an inevitable global trend in the 21st century. It can be accomplished through more broad and active reverse logistics globally, resulting in use of less fossil fuels, finally reducing carbon dioxide and other pollutants. Many countries such as U.S., Japan, EU nations have already set up policies related to carbon reduction, so-called 'green policies.' This paper aims to identify evaluation criteria for logistics policies and relative importance among those criteria, especially in the field of ports and in-land hub terminals. We examined projects related to carbon reduction from domestic and foreign ports and logistics centers and found evaluation factors and assessment indicators. With pre-evaluative items and pre-assessment indicators, we have done a survey and selected evaluation factors and assessment indicators for ports and inland hub terminals in Korea. By analyzing the mutual importance of each pre-evaluative items and pre-assessment indicators related to carbon reduction policies, this research provides guidelines on selecting the key items for the propulsion of carbon reduction projects. This study shows the importance of preliminary evaluation items and indexes with AHP in evaluating carbon reduction policies and the result shows the restrictions and change in transportation and use of alternative fuels. Lastly, it provides a guideline to policy-makers and firm managers in the field of green logistics.