The levels of sulfites in wooden chopsticks were analyzed using two different methods, distillation- alkali titration and ion chromatography. According to the two methods, Sulfur dioxide (SO₂) was validated by 0.6 and 0.2 μg/ml of limit of detection (LOD), 1.8 and 0.5 μg/ml of limit of quantification, (LOQ) and a R² > 0.998 for linearity, respectively. The recoveries of SO₂ from food simulants spiked ar levels of 100 ppm were 70.2-100.2%. 158 samples of wooden chopsticks were monitored the migrated amounts of sulfites. Sulfites were detected in 30 samples in ranged of 0.6 to 15.5 ppm. Maximum migration level, 15.5 ppm of sulfites was considered giving no harmful effect to human since it was reached 5.5% of estimated SML.

본 연구에서는 타당한 지하조건을 모사하기 위한 실험장치를 글로버박스(Glove-box) 내에 설치하고 천연지하수 및 자연균열을 가진 화강암 시추코어를 이용하여 핵종이동 실험을 수행하였다. 암반코어의 균열을 통한 지하수 유동을 해석하기 위하여 비수착성 음이온 핵종인 Br로 지하수 유동실험을 수행하였다. 암반 균열을 통한 우라늄 이동 실험결과에서 유출된 우라늄의 파과곡선이 비수착성 핵종인 Br와 유사한 거동을 보여주었는데, 이는 주어진 지하수 조건에서 우라늄이 주로 탄산염과 결합된 음이온 복합체로 이동하기 때문인 것으로 추정된다. 아울러 균열충전광물에 대한 우라늄의 회분식 수착실험을 수행한 결과, 균열충전광물에 대한 우라늄의 분배계수 는 약 2.7 mL/g로 낮게 나타났다. 이러한 우라늄 수착실험 결과는 빠른 유출을 보인 우라늄 이동실험 결과와 일치한다. 균열암반을 통한 우라늄 이동의 지 연 특성을 보다 자세히 분석하기 위하여 회분식 수착실험으로 부터 구한 값을 이용해 지연인자 값 를 구하고 이동실험 결과로부터 구한 값 과 비교한 결과, 서로 매우 유사한 지연인자 값을 가진다는 것을 알 수 있었다. 이는 화강암 코어의 균열을 통한 우라늄의 이동 지연이 주로 균열충전광물에 의해 이루어지고 있음을 의미하는 것이라고 하겠다.

전기탈이온 장치를 통한 니켈이온의 이동메커니즘이 이온교환섬유의 전기화학적 특성을 이용하여 조사되었다. 포러스 플러그 모델과 확장된 넌스트-플라크 식이 니켈이온의 이동 현상의 해석을 위해서 적용되었다. 적용된 모델을 통해 전기탈이온 시스템의 성능증가는 이온교환섬유를 통해 변화되는 이동도에 기인하는 것이 아니라, 이온교환매개체의 자체 전도도에 의해 일어나는 전류 유발 효과에 의한 것으로 나타났다. 또한, 최적의 전기탈이온 공정운전이 최소화된 전기적 재생영역하에서 일어남을 본 연구를 통해 제시되었다.

본 연구는 제주지역에서 계절초기 벚나무깍지벌레 방제적기를 구명하고자 월동성충의 산란시기 및 부화약충의 이동시기를 조사하였으며, 이 자료를 기존에 보고된 뽕나무깍지벌레 적산온도 예찰 모형에 적합하여 비교 검토하였다. 벚나무깍지벌레 암컷 월동성충은 4월 중하순부터 산란을 시작하여 5월 상순에는 그 알이 부화하기 시작하였으며, 5월 중순경 부화약충의 이동이 가장 활발하였다. 이와 같은 봄철 벚나무깍지벌레 발생시기는 우리나라 남부지역 및 일본 중부지역에서 보고된 뽕나무 깍지벌레 발생시기와 대체적으로 일치하였다. 또한 봄철 뽕나무깍지벌레의 >50% 부화 난괴 발생비율(y) 추정 적산온도 모형(y=1/[exp(-(-a+bx))], , a=-18.80, b=0.073, x=적산온도, 1월 1일부터 발육영점온도 적용)은 벚나무깍지벌레 부화약충 이동시기와 일치하여 봄철 벚나무깍지벌레 방제적기 추정에 유용하게 이용될 수 있을 것으로 판단되었다.

The actual overall migration data obtained from plastic food packaging materials into food simulants under high temperature testing conditions as described in the regulations of European Union, USA, and Korea or Japan were compared. Overall migration values(OMVs) with non-fatty food simulants under high temperature conditions were observed to be generally below 2.5 mg/dm^2 except polyamides(CPA and PA 6,6) which were tested at 121 for 2 hrs. As for the fatty food simulants, the OMVs with soybean oil were higher than other simulants. Among the films tested, PVC wrap showed higher OMVs ranging betwn 23.9 and 54.6 mg/dm^2 than others. The OMVs were measured at higher level with the elevation of contact temperature and the extension of contact time, and in fatty food simulants rather than in non-fatty simulants. Under similar testing temperature and time conditions. the OMVs tended to be increased in polar films like PA with polar simulants, and contrarily in non-polar films like PO with non-polar simulants. It is noteworthy that a discrepancy with regard to the result of OMVs was observed for some films as a result of different migration testing methods and conditions of each country areas.

본 실험에서는 수리구조물의 보호되는 토립자의 필터내 이동과 이로인한 필터의 기능 저하를 실험을 통하여 비교분석한 결과 다음과 같은 결론을 얻었다. 1. 수두가 높고 공극이 클수록 필터내 세사의 이동은 심했으며 조기에 흐름의 안정화에 도달하게 되었지만 필터외부로의 입자유출도 많았으며, 공극이 작고 유속이 빠르면 필터와 모래의 접촉면에 인접한 곳에서 Blocking현상이 크게 일어남을 알 수 있었다. 2. 필터기능에 영향을 주는 세사의 이동은 공극의 크기와 수두에 큰 영향을 받음을 알 수 있었고, USCE 필터와 USSPL 필터는 공극이 크기 때문에 같은 조건하에서 흐름의 안정이 다른 필터들 보다 조기에 이루어 졌다. 3. 세사의 이동잔류량은 USSPL, USCE, USBR, Newton & Hurley, Bertram 필터순으로 많이 나타났다. 4. 흐름의 안전에 소요된 시간은 Bertram, Newton & Hurley, USBR, USSPL, USCE 필터순으로 적었고, 투수계수는 USBR, Bertram, Newton & Hurley, USSPL, USCE 필터순으로 크게 나타났다. 5. 여러 가지 종류의 필터기준중 USCE와 USSPL기준의 필터가 투수계수의 안정에 소요된 시간이 가장 짧고, 세사의 이동량이 적으므로 가장 적합한 것으로 인정된다.

The speed of vertical migration and the volume backscattering strength of the scattering layers during the evening and morning transitions between day and night were measured in November 1990-1992 in thermally stratified waters of the East China Sea. Acoustical measurements were carried out using a scientific echo-sounder operating at t재 frequencies of 25 and 100kHz, and using an echo-integration system connected with a micro-computer. Biological sampling was accomplished by bottom trawling to identify fish species recorded on the echo sounder, and the species and length compositions were determined. The values of scattering strength were allocated to group of fishes according to the fish traces on the echo recording paper and the species composition of trawl catches. The vertical velocities of migration derived from the changes in the depths and the values of peak scattering strength of the dense layer vertically migrating toward the bottom or toward the surface. The trawl data suggest that snailfish and fishing frog were the most abundant fishes in all research stations. As sunrise approached, the fish formed a strong concentration just above the thermocline. The the highest values of scattering strength in the entire water column appeared in the depth strata above the thermocline just before the begining of downward migration. As soon as the fish began to migrate downwards across the thermocline, the values of the scattering strength in the depth strata above the thermocline rapidly decreased, while the values for the scattering layer moving slowly toward the bottom gradually increased. During the 1992 surveys, the speed of the vertical migration was estimated to be 0.38m/min in the upward migration and 0.32m/min in the downward migration, respectively. That is the rate of vertical migration was slightly higher at dusk than at dawn. Similar migration patterns were observed on different stations and under different weather conditions during the surveys in 1990.

전자현미분석기를 이용한 규산염 유리의 정량화학조성 분석 시 알칼리 원소, 특히 Na이 전자빔에 의해 분석 영역 밖으로 이동(migration)하면서 X선 측정 세기가 시간에 따라 감소하는 현상은 오래 전부터 알려져 왔다. EPMA로 규산염 유리의 Na 함량을 정확하게 측정하기 위해서는 전자빔에 의한 Na 이동을 최소화하는 분석방법을 적용하거나 Na 이동에 따른 X선 측정 세기의 감소 효과를 보정해 주어야 한다. 본 연구에서는 X선 세기의 시계열 변화 곡선을 이용해 Na 이동에 의한 X선 감소를 보정할 수 있는 Probe for EPMA 소프 트웨어의 Time Dependent Intensity(TDI) 보정 기능을 이용해 규산염 유리 표준시료 8종의 Na을 분석하였다. 일반적인 지질시료 분석 조건인 15 kV 가속전압, 20 nA 전류 세기 하에서 TDI 보정의 정확도를 검증하였다. 연구 결과 20 μm 크기의 큰 전자빔을 사용했을 때는 Na 감소가 거의 일어나지 않아 보정 없이도 Na의 함량을 정확하게 측정할 수 있었다. 빔의 크기가 10 μm 이하일 때는 Na 감소가 일어나 최대 -55%에 달하는 큰 오차가 발생하는데 TDI 보정을 적용해 이 오차를 ±10% 이내로 줄일 수 있다. Na X선 시계열 변화의 초기 측정값에 가중치를 주고 변화 추세를 선형적으로 가정하는 방법을 사용하면 상대오차를 ±6% 이내로 더 줄여 정확한 Na2O 함량을 얻을 수 있었다. 따라서 알칼리 원소가 많이 포함된 유리질 시료에서 분석 영역이 충분히 크지 못해 작은 전자빔을 사용해야만 한다면 적절한 TDI 보정을 반드시 해주어야 정확한 조성을 얻을 수 있다.

This study aimed to explain the factors that influenced an individual’s decision to migrate. The method of analysis in this study was the estimation of the probit regression model with data from the Indonesian Family Life Survey (IFLS-5), which covered 30,000 individuals from 13 provinces in Indonesia. Data from IFLS-5 were longitudinal data, meaning that the study was looking for data consistently to get reliable data from respondents. The research variables to determine the individual’s decision to migrate were education level, income level, employment status, marital status, land ownership status, health quality, gender, residence status, and poverty status. Individual decision to migrate as a dependent variable was placed as a dummy variable. The results showed that the level of education, income level, employment status, marital status, land ownership status, health quality, and poverty status significantly influenced an individual’s decision to migrate. Meanwhile, gender and residence status did not significantly affect an individual’s decision to migrate. This research recommends that it is necessary to pursue a policy of economic equality between regions because economic factors are the main trigger for an individual’s decision to migrate. Policies to overcome economic disparities among regions will reduce the individual’s decision to migrate.

This study described the characteristics of the upstream migration of salmon (Chum salmon, Oncorhynchus keta) along Yeon-gok Stream in the eastern coastal region of Korea from October 24 to November 9, 2018 using radio tag and data storage tag loggers for the detection of the locations of tagged salmon and measurement of water temperature. Tracking experiments were conducted and classified into four types (case 1 to case 4) depending on the release time and the number of salmon tracked. Experiments from case 1 to case 3 were classified depending on the number of salmon tracked into cases in which a single tagged salmon was tracked (case 1), a pair of tagged salmon was tracked (case 2), and salmon were tracked by different sex ratios (case 3). Experiments from cases 1 to 3 were conducted between 10 AM and 1 PM, and case 4 was conducted after 3:30 PM. Salmon moved and spawned in the downstream region of the Yeon-gok, where water temperature is higher than in other rivers and salmon return in Canada, Russia, Japan, and the U.S.A. Most of the radio-tagged salmon swam in deep and shaded areas during the day but actively moved upstream close to sunset, regardless of the release time. Females showed relatively more active movements than males during upstream migration.

This study analyzes the effect of the level of satisfaction with the living environment of rural people on migration. The analysis data were used by the Rural Development Administration for the survey of welfare systems for farmers and fishermen in 2017, and samples of 3,776 were used for the analysis. The analysis variables were divided into a group of migrants, a group of permanent residents, and a group of decision-keeping, and the level of satisfaction with the living environment of each of the 10 rural areas was used as an independent variable. According to the analysis results, the basic living base and safety of rural residents were having a positive effect. The results show that the projects for developing rural areas, which increase the basic living base, are making substantial contributions to preventing the breakaway of the rural population. Safety has been neglected in the area of rural planning, but if the level of discontent is not enough, it has had the greatest impact on the livelihoods of rural residents. Welfare and cultural leisure set the main demand level for welfare and cultural leisure to the elderly and vulnerable classes, and interpret it as a result of weakened defense against stress from relocation of residence, difficulty of migration due to low income levels, and migration. Therefore, the paradoxical analysis results could be interpreted as showing that measures to increase the satisfaction of the people on welfare and cultural leisure should be taken.

Imagined ethnic ties and affinities have funneled many Koryŏ saram into South Korea—the divided homeland of their ancestors—as coethnic labor migrants and foreign spouses over the past decade. Based on in-depth interviews with ten Uzbekistan-born Koryŏ saram women who currently reside in South Korea with their Korean husbands and children, this paper examines intersections of gender and ethnicity in the women’s migratory paths and life experiences in the employment and family spheres. After contextualizing the ensuing influx of Koryŏ saram to South Korea from the perspectives of ethnic (return) migration and marriage migration, this study looks into how the ten informants’ skills are devalorized as coethnic migrants who lack Korean language skills but appear “Korean” to contemporary South Korean people. This research also investigates the ways that the incipient Koryŏ saram community allows them to seek new employment opportunities while juggling between work and family as a married migrant with children. By examining two salient social differentiations in (social) mobility of Koryŏ saram, this paper not only betokens the social position of Koryŏ saram in South Korea, but also underscores the agency of the coethnic migrant women who struggle to pursue inclusion in the affluent homeland.

Human adult stem cells have widely been examined for their clinical application including their wound healing effect in vivo. To function as therapeutic cells, however, cells must represent the ability of directed migration in response to signals. This study aimed to investigate the mechanism of platelet-derived growth factor (PDGF)-induced migration of the human abdominal adipose-derived stem cells (hADSCs) in vitro. A general matrix metalloproteinase (MMP) inhibitor or a MMP2 inhibitor significantly inhibited the PDGF-induced migration. PDGF treatment exhibited greater mRNA level and denser protein level of MMP1. The conditioned medium of PDGF-treated cells showed a caseinolytic activity of MMP1. Transfection of cells with siRNA against MMP1 significantly inhibited MMP1 expression, its caseinolytic activity, and cell migration following PDGF treatment. Phosphatidylinositol 3-kinase (PI3K) inhibitor reduced the migration by about 50% without affecting ERK and MLC proteins. Rho-associated protein kinase inhibitor mostly abolished the migration and MLC proteins. The results suggest that PDGF might signal hADSCs through PI3K, and MMP1 activity could play an important role in this PDGF-induced migration in vitro.

Catch data for the common squid (Todarodes pacificus), classified by squid-jigging fisheries per grid (size: 0.5° latitude × 0.5° longitude), and the water temperature values KODC (Korea Ocean Data Center) were collected for the 1980–2009 period to study the changes in squid distribution and migration with climate regimes (1980s, 1990s, and 2000s). The primary fishing period in the 1990s and 2000s was approximately 2–3 months earlier than that in the 1980s. Especially in the East Sea, the fishing grounds in the 1980s stayed longer at high latitudes than those in the other decades. Moreover, in the 1980s, centers of the fishing ground were located near the Yamato bank (central East Sea), whereas in the 1990s and 2000s, they were situated near the southeastern coast of the Korean peninsula.