This paper examined factors affecting Korean EFL learners’ word association types in their L2 mental lexicon. Specifically, vocabulary size of the learners was examined to see if it had any significant relationship with word association types. To this end, experiment procedures that included vocabulary size test and the lexical decision task as well as the word association task were conducted on 40 Korean EFL learners. Reaction time and accuracy of responding to word associations in the lexical decision task were measured. Subsequently, a correlation analysis was conducted with their vocabulary size. Additionally, learners’ word association types were analyzed based on the results of word association task. The results showed that Korean EFL learners’ vocabulary size had significant correlations with their accuracy in identifying syntagmatic and paradigmatic associations, but not in the phonological association. However, their accuracy was not correlated with reaction times. The results indicate that L2 learners’ mental lexicon is partially dependent on their vocabulary size of the target language, and it is variable depending on word association types.

최근 관광, 레저 수요의 증대로 해안 시설물(방파제)에서 낚시를 통해 여가를 즐기는 낚시객의 증대와 아울러 매년 해안 시설물인 소파블록(Tetrapod, TTP)에서의 낙상사고가 사회적 문제가 되고 있다. 본 연구에서는 낙상사고가 주로 발생하는 소파블록을 안전망으로 덮어 낚시객의 낙상을 저감하는 안전사고 방지 시설물 개발의 기초 연구로서 적절한 그물코 크기를 제시하고자 한다. 이는 안전망 시설물의 규모 및 경제성을 고려할 때 반드시 선행되어야 할 부분이다. 본 연구에서 적용한 안전망의 그물코 크기 결정 방법은 낚시객들의 성별, 연령별 현황과 한국인의 인체치수조사 결과를 바탕으로 최적의 그물코 크기를 산정하고자 하였다. 그 최종 결과로서 안전망의 그물 코 크기는 최소 낚시객의 넙다리 둘레에서부터 최대 가슴둘레까지를 고려하여 18.6~27.0 cm의 범위로 산정되었다.

Outdoor air pollution with particulate matter has become more severe in Korea. Ambient particle concentration affects the indoor environment through various routes through building envelopes. In this study, we investigated particle exposure in residential buildings. Indoor and outdoor particle sources determined the indoor concentrations and particle exposure. This paper measured indoor particles and CO2 concentrations in two different apartment buildings and conducted the survey for 24 hours. The I/O ratio of the occupant awake period was higher than the asleep period. The I/O ratio in the awake period is 0.93-3.65, while the I/O ratio in the asleep period is 0.31- 0.76.Indoor peak events such as cooking or cleaning temporarily increase the I/O ratio and emit the indoor particle sources. Decay rate constant is 0.49-6.84 (1/h) in the indoor peak events during the operation of the exhaust hood and natural ventilation. The size range of 0.3-0.5 μm size is over half for the proportions of emitted particles (55.6%). Daily exposure is divided into indoor sources (45.2%) and outdoor sources (54.8%). We found the differences for the proportion of particle exposure. The ratio of daily exposure in particles for 0.3-0.5 μm size is 43.1 (indoor)/ 56.9 (outdoor) %. However, indoor sources are higher than outdoor sources for the ratio of daily exposure in particles for the 0.5-10.0 μm size.

It is known that the number of astronomers of a country registered to the International As- tronomical Union (IAU) is correlated with that country’s gross domestic product (GDP). However, the robustness of this relationship could be doubted, as the fraction of astronomers joining the IAU differs from country to country. Here we revisit this correlation by using more recent data, updated as of 2017. We find a similar correlation by using the total number of astronomers and astrophysicists with PhD degrees that are working in each country, instead of adopting the number of IAU members. We confirm the existence of the correlation. We also confirm the existence of two subgroups within this correlation. One group consists of advanced European countries having a long history of modern astronomy, while the other group consists of countries having experienced recent rapid economic development. In order to determine the cause for the correlation, we obtained the long-term variations of the number of as- tronomers, population, and the GDP for a number of countries. We find that the number of astronomers per capita for recently developing countries has increased more rapidly as GDP per capita increased, than that for fully developed countries. We collected demographic data of the Korean astronomical community and find that it has experienced recent rapid growth. From these findings we estimate the proper size of the Korean astronomical community by considering Korea economic power and population. The current number of PhD astronomers working in Korea is approximately 310, but it should be 550 in order for it to be comparable and competitive to the sizes of the Spanish, Canadian, and Japanese astronomical communities. If current trends continue, this number will be reached by 2030. In order to be comparable to the German, French, and Italian communities, there should be 800 PhD astronomers in Korea. We discuss ways to overcome the vulnerability of the Korean astronomical community, based on the statistics of national R&D expenditure structure in comparison with that of other major advanced countries.

본 연구는 중학교 교육과정에서 수학과 연계된 지구과학 실험 중 지구의 크기 측정을 중심으로 총 30시간 동안 지구과학 교육봉사 활동에 참여한 예비 지구과학교사와 중학생들에게 본 프로그램이 주는 의미를 살펴보고 혁신적 수업으로의 가능성을 탐색해 보았다. 중학교 과학 교과서에 소개된 고대 그리스 시대 에라토스테네스의 그림자 길이를 이용한 지구 크기 측정 실험에서 나타나는 오차를 최소화하기 위하여, 멀리 떨어진 수도권과 지방의 두 개의 중학교에서 삼각비를 이용한 탐구 활동을 수행 한 후, 실측한 자료를 두 학교 학생들이 공유하여 지구의 크기를 최종적으로 계산하였다. 이 과정을 통해 실측 자료를 효과적으로 표현하는 수학적 방법을 배우며, 반복적이고 정확한 자료 획득 과정의 중요성과 어려움을 체험하고, 도출된 결과에 포함된 오차의 원인들에 대해 토론하였다. 본 연구 결과는 학생들이 지구과학 탐구의 특성을 이해하고, 2015 개정 교육과정에서 과학과 수학교과에서 공통적으로 강조하고 있는 교과 역량인 문제 해결력, 사고력, 의사소통 능력을 함양할 수 있는 수학·과학 통합 프로그램 개발에 기초 자료를 제공할 것이다.

This study demonstrates the effect of addition of Fe particles of different sizes on the critical properties of the superconductor MgB2. Bulk MgB2 is synthesized by ball milling Mg and B powders with Fe particles at 900oC. When Fe particles with size less than 10 μm are added in MgB2, they easily react with B and form the FeB phase, resulting in a reduction in the amount of the MgB2 phase and deterioration of the crystallinity. Accordingly, both the critical temperature and the critical current density are significantly reduced. On the other hand, when larger Fe particles are added, the Fe2B phase forms instead of FeB due to the lower reactivity of Fe toward B. Accordingly, negligible loss of B occurs, and the critical properties are found to be similar to those of the intact MgB2.

목적 : 본 연구에서는 근시안에서 동공 크기에 따른 굴절이상도의 차이에 영향을 미치는 요인을 알아보고자 하였다. 방법 : 백내장을 제외한 안질환 및 안 수술의 과거력이 없고, 근시안이며 최대 교정시력이 1.0 이상인 18~58 세의 성인 75명(75안)을 대상으로 하였다. i.profilerplus(Zeiss, Germany)를 이용하여 반암실 상태(5~50 lx)에서 동공 중심부 5 mm와 3 mm 영역에서 현성굴절검사와 각막 및 안구의 수차 검사를 실시하였다. Paired t-test를 이용하여 동공 크기에 따른 측정값 평균의 차이를 비교하였다. Spearman correlation test를 이용하여 동공 크 기에 따른 평균 구면렌즈 대응치의 차이와 고위수차의 상관성을 알아보았고, Multiple regression analysis를 시 행하여 동공 크기에 따른 평균 구면렌즈 대응치의 차이에 영향을 미치는 인자를 평가하였다. 결과 : 평균 구면렌즈 대응치는 5 mm와 3 mm에서 각각 -4.08±2.90 D와 -3.84±2.95 D로 유의한 차이를 보였다(p<0.001). 동공 크기에 따른 평균 구면렌즈 대응치의 차이(5 mm에서 평균 구면렌즈 대응치 -3 mm에서 평균 구면렌즈 대응치)와 안구의 고위수차는 통계적으로 유의한 음의 상관관계를 보였다(r=-0.676, p<0.001). 연령과 성별을 보정 한 후 동공 크기에 따른 평균 구면렌즈 대응치의 차이(≥0.25 D) 유무에는 구면수차(spherical aberration, Z40)와 수직난시수차(vertical astigmatism, Z4-2)가 영향을 미치는 것으로 나타났다. 결론 : 근시안에서는 눈의 고위수차와 저위수차의 상호작용으로 동공 크기에 따른 평균 구면렌즈 대응치의 차이가 생길 수 있으므로, 고위수차 검사 결과 값을 고려한 교정 도수를 통하여 안경 착용 시 만족도를 증가시켜야 할 것으로 생각된다.

Discarding juvenile fishes under girth 16 cm nearly equal to inner perimeter of codend mesh size collected by a cover net method in bottom trawl. The body size of the main five species (mackerel, horse mackerel, sea bream, melon seed and black throat seaperch) was measured for their body length, girth, weight, height and width and analyzed size selectivity. Frequency of penetrating fish as retention in a cover net was less than 40% of total number of juvenile discarding fish. The most of body length or girth of five species were significantly different between in the codend and in the cover net. The 50% selection girth in the cover net ranged 8-11 cm were smaller than those in the codend ranged 9-13 cm by the species respectively. The 50% selection body length was significantly related with the ratio of body height (H) by body width (W) both for in the codend or in the cover net while 50% selection girth was not significantly related with H/W. Furthermore 50% selection fish size by fish species between in the codend and in the cover net was not significantly different both in body length or girth. Therefore, the girth selectivity represented possibly as one unique value regarding fish body shape was considered as more useful method for multi-species catch in trawl.

This research was conducted to figure out the optimal size of the plug cell and seedling raising period in ‘Nongwoo’ and ‘Nonghyeop’ cultivars. In the first experiment on effect of plug cell size on growth of squash, seedlings were transplanted into hydroponic cultivation beds at different growing stages: Those in 32-cell trays with 3-4 true leaves at 25 days after sowing, those in 50-cell trays with 2 true leaves at 15 days after sowing, those in 105-cell trays just before a true leaf development, and those in 162-cell trays with only cotyledons at 8 days after sowing. In the second experiment on effect of seedling raising period on growth of squash, it was conducted to have different sowing dates. But the same transplanting date, based on the results of Experiment 1, and compared the differences in growth and fruit productivity as affected by plug cell size in the same way with experiment 1 including the cultivars and environmental conditions. After setting the transplanting date in advance, the number of days for sowing were calculated back for each treatment. In the first experiment, plant height was the greatest in 105-cell trays followed by 162, 50 and 32-cell trays in both cultivars. The best fruit quality was found in different treatments depending on the cultivars, although it was the lowest in 32-cell trays in both cultivars. The fruit quality was not significantly different among those from cell sizes. Therefore, when raising seedlings in 105-cell trays, the period of raising seedlings can be shortened as compared with the conventional 32-cell trays, and this change could reduce the workforce required for growing and transplanting seedlings. In the second experiment, after transplanting, shoot height and leaf width in the first measurement in both cultivars were greater in the 32-cell treatment. However, the last measurement after four weeks showed no significant difference in plant height, but significantly greatest leaf width in the smallest cell treatment, even as compared with that in 32-cell treatment. In case of ‘Nongwoo’, length and weight of the first harvested fruit showed the highest values in the treatment of 105-cell trays. In case of ‘Nonghyeop’ the 162-cell treatment along with the 105-cell treatment showed greatest length and weight of the first fruits. From these results, zucchini plug seedlings can be raised in plug trays with reduced cell sizes than the conventional 32-cell trays with improved fruit productivity.

In Brazil overwieght people represent 58,2%, in the USA 40% of women’s population. Plus size is a standard of USA fashion industry that applies to woman who wears more than 12, and in Brazil it begins on 44. They are frustrated, because retails provide few options and don’t understand them.

The growth and employment effects of R&D investment were analyzed according to business size, export value and manufacturing sectors so as to suggest improvement directions for effective industry policies. The effect of R&D investment was considered simultaneously from the two perspectives of growth and employment effect, and the causality analysis was carried out by using a path analysis. The result of the path analysis confirmed significant differences in the growth effect of R&D investment depending on business size. However, the effect of increasing employment was difficult to obtain statistically significant results for any various combinations of business size and export value. This is a mixture of directions for the effects of R&D investment on employment, which could be due to the failure to consider appropriate time lags between investment and effect. Efficiency analysis by industry sectors confirmed significant differences in efficiency depending on business size, but differences depending on export value were difficult to identify. In order to derive improvement policy by industry sector according to business size and export value, the direction of selective support policy and universal support policy was derived for six industry groups by combining the return to scale in the efficiency analysis and R&D concentration. Hirschman-Herfindahl index is used for calculating R&D concentration.

강원지역은 우리나라의 다설지로서 복잡한 지형 때문에 강설량의 공간변동성이 크다. 특히 동풍조건에서 강설이 발생할 시 강설량의 공간적 변동을 예측하기 어렵다. 동풍조건에서는 강원지역 내 위치에 따라 대기환경조건이 다르며 이는 강설의 특성에도 영향을 줄 수 있다. 본 연구에서는 동풍 조건에서 태백산맥의 풍상측과 풍하측에서 강설의 미세 물리적 특성을 서로 비교 분석하였다. 강원지역 내 4개 관측지점을 선정하여 파시벨 수적계로 입자크기분포를 관측하였다. 얻어진 강설입자 크기 분포의 특성을 풍상측과 풍하측간 비교한 결과, 풍상측의 강설입자 크기 분포는 풍하측에 비해 넓은 분포를 가졌고 작은 강설입자의 수도 많았다. 강설입자의 수농도에 비례하는 보편특성수농도와 강설입자의 직경에 비례하는 보편특성직경 둘 다 풍상측에서 상대적으로 큰 값을 보였다. 또한, 얼음수함량과 강설강도 비교에서도 풍상측 지점에서 큰 평균값을 가졌다. 이 결과가 나타난 원인은 태백산맥 산사면에서 공기덩어리의 강제적 상승효과로 풍상측 지점 상공에 새로운 강설입자의 생성이 활발했기 때문으로 추정된다. 또한, 풍상측은 따뜻하고 습한 동풍이 불어오므로 이로 인해 지상기온이 0oC 근처에 머무르며 강한 부착과정이 일어나기 좋은 조건이다.

Tungsten heavy alloys (W–Ni–Fe) play an important role in various industries because of their excellent mechanical properties, such as the excellent hardness of tungsten, low thermal expansion, corrosion resistance of nickel, and ductility of iron. In tungsten heavy alloys, tungsten nanoparticles allow the relatively low-temperature molding of high-melting-point tungsten and can improve densification. In this study, to improve the densification of tungsten heavy alloy, nanoparticles are manufactured by ultrasonic milling of metal oxide. The physical properties of the metal oxide and the solvent viscosity are selected as the main parameters. When the density is low and the Mohs hardness is high, the particle size distribution is relatively high. When the density is high and the Mohs hardness is low, the particle size distribution is relatively low. Additionally, the average particle size tends to decrease with increasing viscosity. Metal oxides prepared by ultrasonic milling in high-viscosity solvent show an average particle size of less than 300 nm based on the dynamic light scattering and scanning electron microscopy analysis. The effects of the physical properties of the metal oxide and the solvent viscosity on the pulverization are analyzed experimentally.

본 연구는 두록종 돼지의 복당 생시체중 형질(복당 생시체중 평균, 복당 생시체중 표준편차)과 산자수 형질(총 산자수, 생존 산자수, 사산두수)의 유전모수를 추정하고 이들 형질간의 상관관계와 개량방안을 알아보기 위해 실시하였다. 분석에는 국립축산과학원에서 2006~2016년 사이에 분만한 두록 모돈 1,081복의 자료를 이용하였다. 분석형질은 복당 생시체중 평균(ABW), 복당 생시체중 표준편차(BWSD), 총 산자수 (NB), 생존 산자수(NBA) 및 사산두수(NBD)이다. 유전모수 추정은 다형질 개체모형을 이용하였다. 각 형질에 대한 유전력은 복당 생시체중 평균(ABW), 복당 생시체중 표준편차(BWSD), 총 산자수(NB), 생존 산자수(NBA) 및 사산두수(NBD)에 대해 각각 0.32, 0.13, 0.11, 0.10, 및 0.06으로 추정되었다. 복당 생시체중 평균(ABW)과 복당 생시체중 표준편차(BWSD)는 0.75의 높은 정의 유전상관을 보인 반면 생존 산자수(NBA)와 복당 생시체중 평균(ABW), 복당 생시체중 표준편차(BWSD)간의 유전상관은 각각 –0.26, -0.40로 생존 산자수(NBA)가 증가함에 따라 복당 생시체중 평균과 복내 개체간 체중의 표준편차는 감소하는 것으로 나타났다. 생존 산자수(NBA)와 사산두수(NBD)간의 유전상관은 0.24로 생존 산자수(NBA)가 증가하면 사산두수(NBD)도 증가하는 유전적 관계를 나타내었다. 한편 복당 생시체중 평균(ABW)과 복당 생시체중 표준편차(BWSD), 사산두수(NBD), 총 산자수(NB)간의 유전상관은 각각 0.75, 0.81과 0.08로 추정되어 복당 생시체중 평균(ABW)이 증가하면 총 산자수(NB)의 큰 변화 없이 복당 생시체중 표준편차(BWSD), 사산두수(NBD)가 증가하는 것으로 나타났다. 본 결과로 미루어 볼 때 유전력이 높은 복당 생시체중 평균(ABW)은 직접선발을 통한 빠른 개량이 가능한 반면 복당 생시체중 표준편차(BWSD), 총 산자수(NB), 생존 산자수(NBA) 및 사산두수(NBD) 형질은 직접선발을 통한 개량 효과가 낮을 것으로 판단된다. 특히 자돈 생시체중의 균일도를 개량하고자 한다면 복당 생시체중 표준 편차(BWSD)에 대한 직접선발 방법과 더불어 복당 생시체중 평균(ABW)을 이용해 간접선발하는 방법 또한 이용 가능할 것으로 사료된다.

The photovoltaic properties of TiO2 used for the electron transport layer in perovskite solar cells(PSCs) are compared according to the particle size. The PSCs are fabricated and prepared by employing 20 nm and 30 nm TiO2 as well as a 1:1 mixture of these particles. To analyze the microstructure and pores of each TiO2 layer, a field emission scanning electron microscope and the Brunauer–Emmett–Teller(BET) method are used. The absorbance and photovoltaic characteristic of the PSC device are examined over time using ultraviolet-visible-near-infrared spectroscopy and a solar simulator. The microstructural analysis shows that the TiO2 shape and layer thicknesses are all similar, and the BET analysis results demonstrate that the size of TiO2 and in surface pore size is very small. The results of the photovoltaic characterization show that the mean absorbance is similar, in a range of about 400-800 nm. However, the device employing 30 nm TiO2 demonstrates the highest energy conversion efficiency(ECE) of 15.07 %. Furthermore, it is determined that all the ECEs decrease over time for the devices employing the respective types of TiO2. Such differences in ECE based on particle size are due to differences in fill factor, which changes because of changes in interfacial resistance during electron movement owing to differences in the TiO2 particle size, which is explained by a one-dimensional model of the electron path through various TiO2 particles.