본 연구는 한국 산림지역에 조성된 각종 산림도로의 밀도를 산정하고, 이를 토대로 한국 산림도로망의 현황과 문제점 을 평가하였다. 분석은 산림청에서 제공하는 임상도와 임도 현황, 국토교통부의 도로중심선 데이터를 활용하여 산림 내부 및 인접 지역(산림 경계로부터 75m 이내)에 위치한 도로의 총길이를 계산하고, 이를 전체 산림면적으로 나누어 산림도로 밀도를 산정하였다. 분석 결과, 한국의 산림도로 밀도는 전국 평균이 무려 51.0m/ha에 달하였다. 이는 일본의 산림도로 밀도 24.1m/ha, 오스트리아 전체 산림의 도로 밀도 37.0m/ha, 오스트리아의 경영림을 대상으로 한 산림도로 밀도 45.0m/ha와 비교했을 때 현저히 높은 수치였다. 이러한 차이는 한국의 산림 도로망이 관리와 경영을 위한 요구 조건을 훌쩍 넘어섰음을 시사하며, 추가적인 도로 건설은 경제적 비효율성을 초래할 수 있음을 나타낸다. 산림 경영에 필요한 적정 도로밀도는 5~14m/ha로 여러 연구에서 제시되고 있다. 이와 더불어 산림생태계에 미치는 부정적 영향은 매우 높을 것으로 판단되었다. 또한, 산불 조기 진화 등을 위한 도로망 확장 필요성 등도 실증적으로 검증되지 않고 있어 현재 임도를 중심으로 한 산림도로 밀도 확장정책은 재고가 필요한 것으로 판단되었다.
본 연구에서는 전하 이동 특성을 가지는 분자[쿠마린(C)-DNP]의 흡수 스펙트럼을 정확하게 예측하기 위해 장거 리 보정 밀도 범함수 이론 (long-range corrected density functional theory, LC-DFT)인 LC-BLYP의 범위 분리 매개변수 (μ)를 여러 가지 피팅 방법을 이용하여 최적화하였다. 기체 상태의 Koopmans 이론을 기반으로 최적화된 μ값은 실험적 흡수 피크에 비해 청색 이동(blue-shift)되는 경향성을, 반대로 용매 환경에서 최적화된 μ값은 과도하게 적색 이동 (red-shift)이 되는 경향성을 보였다. 반면, 실험적 데이터에 맞춰 조정된 μ값은 흡수 스펙트럼의 피크 위치와 세기를 가 장 고정확도로 재현하였으며, 특히 C-DNP와 C-OH 분자에서 나타나는 최대 흡수 피크 에너지의 차이를 잘 예측하였 다. C-DNP의 HOMO와 LUMO 전자 분포는 모든 μ값에서 일정한 모양(shape)을 가지고 있었으며, HOMO에서 LUMO 의 전이는 C에서 DNP로의 분자 내 전하 이동(Intramolecular Charge Transfer, ICT)임을 보였다.
Wheat (Triticum aestivum L.), a significant cereal crop from the Gramineae family, serves as a vital source of protein, essential minerals, B-group vitamins, and dietary fiber. However, its productivity is often hindered by issues such as poor seed germination, which can adversely affect yield and crop quality. This study investigated the effects of different silicon concentrations and priming durations on wheat germination and seedling growth. Analysis of variance revealed that silicon treatment significantly influenced key parameters of germination and growth, including germination percentage (GP), germination index (GI), vigor index (VI), radicle length (RL), plumule length (PL), and seedling dry weight (SDW). Priming with silicon at a concentration of 1 mM resulted in notable improvements, increasing GP, GI, VI, RL, and PL by 10.6%, 65.5%, 29.4%, 18.6%, and 28.6%, respectively, after 6 hours of priming. Certain germination traits demonstrated strong positive correlations, particularly GP and GI (r = 0.96) and VI and RL (r = 0.94), after 4 hours of priming. These improvements in seed germination and seedling development may result from enhanced water uptake, stimulated cell division, and increased hydrolytic enzyme activity, which facilitate the mobilization of seed reserves and accelerate the growth of embryonic tissues.
This study determined the minimum size of a representative molecular structure for use in future dynamic analyses of asphalt binders. The minimum representative size, considering factors such as aging, additive types, and temperature variations, was established using density and radial distribution functions. This approach ensures that the structure reflects temperature-dependent property changes, which are critical characteristics of asphalt binders. In this study, the structure of asphalt-binder molecules was generated using the composition proposed by Li and Greenfield (2014) for AAA1. To assess the appropriateness of the molecular structure size, we generated additional structures, X2 and X3, maintaining the same composition as X1, but with two and three times the number of molecules, respectively, as suggested by Li and Greenfield (2014). Silica and lignin were considered as additives, and the aging conditions examined included unaged, short-term aging, and long-term aging. In addition, 11 temperature conditions were investigated. The density and radial distribution functions were plotted and analyzed. The variables influencing the density and radial distribution functions were set as the aging degree of the asphalt binder (unaged, short-term aging, long-term aging), 11 temperature conditions ranging from 233 to 433 K in 20 K intervals, structure size (X1, X2, and X3), and the presence of additives (no additives, silica, and lignin). For density, clear differences were observed based on the degree of aging, temperature conditions, and presence of additives, whereas the structure size did not significantly affect the density. In terms of radial distribution functions, the X1 structure reflected differences based on the degree of aging and the presence of additives but was limited in exhibiting temperature-dependent variations. In contrast, the X3 structure effectively captured temperature-dependent trends, indicating that the size of the molecular structure is crucial when evaluating energy calculations or physical tensile strength, necessitating careful assessment.
This study aimed to understand the needs of consumers in the meal kit market and determine the impact of meal kit selection attributes according to the consumption behavior of single-person households on purchase decisions and satisfaction. A summary of the results of this study is as follows: First, the most frequent purchase frequency of meal kits was 2 to 3 times a month. The reason for purchase was that it was easy to consume, and the most common purpose of purchase was for consumption. Second, four factors, including health, convenience, taste, and economics, were derived as a result of a factor analysis of meal kit selection attributes. The difference in meal kit selection attributes according to age groups revealed that those in their 20s had high scores with respect to health and taste factors, and economic factors appeared statistically significant. Third, an analysis of the meal kit product selection attributes showed that health and taste factors had a positive influence on satisfaction. This can be said to reflect the tendency of single-person households to give weightage to healthy eating and to purchase products that can be consumed conveniently.
본 연구는 대나무 숲에서 당해년도 발생한 신죽의 양과 재적생장에 관계하는 환경인자를 찾기 위하여 수행되었다. 분석에 사용한 표준지는 120개소였으며, 신죽 발생량과 재적생장에 관여하는 환경인자로는 기존 입목죽의 밀도, H/D형상비, 수관밀도, 해발고, 토양형, 국소지형 등 이었다. 그리고 반응변수는 신죽 발생량과 재적생장을 두고, 설명변수는 이들에 영향하는 환경인자를 두어서, 반응변수와 설명변수 간 관계를 수량화 I 방법으로 분석하였다. 신죽의 발생량에 관여하는 인자는 기존 입목죽 밀도, H/D형상비, 해발고, 토양형, 국소지형인 것으로 나타났으며, 이들의 관계는 다중회귀식 형태의 모델로 도출되었다. 이 추정모델의 설명력은 50.4%였으며, 모델의 통계적 유의성은 5% 유의수준에서 인정이 되었다. 그리고 5개 설명변수 중 내부상관을 배제한 편상관계수를 도출한 결과, 계수는 국소지형, 입목죽의 입목밀도, H/D형상비 순으로 나타났다. 수량화분석 에 의한 신죽 재적생장에 관여하는 인자로는 입목죽의 밀도, H/D형상비, 수관밀도, 해발고로 나타났다. 4개 변수를 이용한 신죽 재적 추정모델은 64.3%을 설명력을 가지며, 통계적 유의수준 5%에서 유의성이 인정되었다. 그리고 편상관계수는 H/D형상비, 해발고, 입목죽의 밀도의 순으로 나타났다.
During the cultivation of wheat sprouts, antioxidant activity was measured during each cultivation period. Wheat sprouts from the cultivation period showing the highest antioxidant activity were added at different concentrations to make wheat sprout sulgidduk. Their physicochemical properties then were measured. As a result, when wheat sprouts were cultivated to about 14 cm, contents of ascorbic acid and polyphenol compounds were the highest. Their ABTS radical scavenging activities also showed high values. Thus, wheat sprouts grown about 14 cm were added at a concentration of 0 to 7% to prepare wheat sprout sulgidduk. The lightness (L) of the control was the highest. Redness (a) and yellowness (b) of wheat sprout sulgidduk increased as the amount of wheat sprout added increased. Contents of ascorbic acid and polyphenol compounds and ABTS radical scavenging activities of wheat sprout sulgidduk added with the highest wheat sprout content were significantly higher than those of others. Regarding the texture, the addition of wheat sprout resulted in slightly higher hardness, gumminess, and chewiness than the control. However, springiness and cohesiveness were not significantly different between treatment groups.
PURPOSES : This study aimed to develop a quantitative structure property relationships (QSPR) model to predict the density from the molecular structure information of the asphalt binder AAA1, a non-full connected structure mixed with a total of 12 molecules. METHODS : The partial least squares regression (PLSR) model, which models the relationship between predictions and responses and the structure of these variables, was applied to predict the density of a binder with molecule descriptors. The PLSR model could also analyze data with collinear, noisy, and multiple dimensional independent variables. The density and additive-free AAA1 binder’s molecule systems generated by an asphalt binder’s molecules-related study were used to fit the PLSR model with the molecular descriptors produced using alvaDesc software. In addition to developing the relationship, a systematic feature selection framework (i.e., the V-WSP- and PLSR-modelbased genetic algorithm (GA)) was applied to explore sets of predictors which contributed to predicting the physical property. RESULTS : The PLSR model accurately predicted the density for the AAA1 binder’s molecules using the condition of the temperature and aging level (R2 was 0.9537, RMSE was 0.00424, and MAP was 0.00323 for the test data) and provided a set of features which correlated well to the property. CONCLUSIONS : Through the establishment of the physical property prediction model, it was possible to evaluate the physical properties of construction materials without limited experiments or simulations, and it could be used to comprehensively design the modified material composition.
This study aimed to determine the optimal planting density for sesame cultivation in a double cropping system after harvesting onion and garlic in the Muan region. It compared the growth, yield, disease susceptibility, and labor hours for two varieties of sesame (Landrace and Geonbaek sesame) at different planting densities. Plant height in the Landrace sesame showed no significant variation with different planting densities, whereas Geonbaek sesame increased in height with higher planting densities. Both cultivars increased the number of viable branches at lower densities. The stem diameter was thicker in Landrace sesame with decreasing planting density, while in the Geonbaek sesame, there was no significant difference in stem diameter regardless of planting density. The number of capsules per plant for the Landrace sesame increased with decreasing density, whereas Geonbaek sesame showed no significant difference. Yield for both cultivars was higher at greater densities. However, the late direct sowing time and shorter cultivation period significantly reduced the yield of sesame cultivated in a double cropping system compared to that of sesame grown in a single cropping system, due to the late direct sowing time and shorter cultivation period. There was no significant difference in disease occurrence based on planting density. Furthermore, although labor hours did not vary with planting density when comparing the labor hours required for cultivating the Landrace sesame and Geonbaek sesame, the latter needed less labor time. This study reveals the optimum planting distance and density for sesame cultivation as a double cropping after harvesting onion and garlic, providing invaluable data for establishing sesame double cropping cultivation techniques.
In this study, we investigated the microstructure and piezoelectric properties of 0.96(K0.456Na0.536)Nb0.95Sb0.05-0.04 Bi0.5(Na0.82K0.18)0.5ZrO3 (KNNS-BNKZ) ceramics based on one-step and two-step sintering processes. One-step sintering led to significant abnormal grain (AG) growth at temperatures above 1,085 °C. With increasing sintering temperature, piezoelectric and dielectric properties were enhanced, resulting in a high d33 = 506 pC/N for one-step specimen sintered at 1,100 °C (one-step 1,100 °C specimen). However, for one-step 1,115 °C specimen, a slight decrease in d33 was observed, emphasizing the importance of a high tetragonal (T) phase fraction for superior piezoelectric properties. Achieving a relative density above 84 % for samples sintered by the one-step sintering process was challenging. Conversely, two-step sintering significantly improved the relative density of KNNS-BNKZ ceramics up to 96 %, attributed to the control of AG nucleation in the first step and grain growth rate control in the second step. The quantity of AG nucleation was affected by the duration of the first step, determining the final microstructure. Despite having a lower T phase fraction than that of the one-step 1,100 °C specimen, the two-step specimen exhibited higher piezoelectric coefficients (d33 = 574 pC/N and kp = 0.5) than those of the one-step 1,100 °C specimen due to its higher relative density. Performance evaluation of magnetoelectric composite devices composed of one-step and twostep specimens showed that despite having a higher g33, the magnetoelectric composite with the one-step 1,100 °C specimen exhibited the lowest magnetoelectric voltage coefficient, due to its lowest kp. This study highlights the essential role of phase fraction and relative density in enhancing the performance of piezoelectric materials and devices, showcasing the effectiveness of the two-step sintering process for controlling the microstructure of ceramic materials containing volatile elements.
In this study, we estimated the distribution density of giant jellyfish in coastal waters of Korea in 2023 and compared the occurrence of giant jellyfish over four years. In May, the giant jellyfish were mainly distributed in the waters of the Yangtze River outflow, and in July, they were highly distributed in the west of Jeju Island and near the south coast of Korea. In addition, when comparing the distribution densities of giant jellyfish in Korea over four years, both acoustic and sighting surveys showed that the highest density of jellyfish occurred in 2021.
두만강 하류의 숲은 북한, 중국, 러시아를 연결하는 중요한 산림생태계로서, 국제적인 멸종위기종인 호랑이(Panthera tigris)와 표범(Panthera pardus)을 포함한 다양한 야생동물들에게 서식환경과 이동경로를 제공하여 준다. 본 연구는 두만강 하류, 특히 중국과 북한을 연결하는 잠재적인 생태통로로서 한반도의 생물다양성 보전과 복원에 중요한 역할을 할 수 있는 밀강 지역에 초점을 맞추고 있다. 2019년 5월부터 2021년 5월까지 이 지역에 설치한 48대의 무인센서카메라 를 통해 출현하는 포유류 종을 확인하고 그들의 상대개체수와 점유율 및 분포 현황을 파악하는 것을 목표로 하였다. 그 결과 총 18종의 포유류가 밀강 지역에 서식하고 있으며, 그 중에는 호랑이와 표범 등 대형 육식동물도 포함되고 있음을 확인하였다. 이 지역의 주요 포유류인 유제류 4종에 대한 점유율과 탐지율, 분포를 추정한 결과, 특히 노루 (Capreolus pygargus)와 멧돼지(Sus scrofa)가 높은 점유율을 보였다. 노루는 모든 지역에 분포하며 예측 점유율은 0.97로 높게 나타났으나, 고도, 도시 주거용지, 패치 밀도 등의 영향을 받는 것으로 나타났다. 멧돼지는 0.73의 예측 점유율을 보이며 전 지역에 분포했으며, 습지 비율, 방목 강도, 사면에 대한 공간이질성 등의 인자가 점유율과 탐지율에 영향을 주었다. 꽃사슴(Cervus nippon)의 예측 점유율은 0.48로서 특정 지역에 국한되어 분포하였으며, 경사도와 서식 지 파편화 다양성이 탐지율에, 방목 강도와 개방된 숲의 비율이 점유율에 각각 영향을 주었다. 고라니(Hydropotes inermis)는 아주 낮은 점유율(0.06)을 보이며 두만강 유역을 따라 분포했으며, 고도가 낮은 곳의 점유율이 높고 사면의 공간이질성이 높은 곳에서 탐지율이 높았다. 본 연구는 밀강 지역이 두만강 하류의 다양한 포유류 개체군을 유지하는 서식지인 동시에, 동물의 이동성과 서식지의 연결성을 유지하는 잠재적 생태통로로서 중요한 역할을 할 수 있음을 확인하였다. 동시에 본 연구에서 개발된 점유율 예측 모형은 향후 인간의 교란에 노출된 두만강 유역의 포유류 분포를 예측하고 국경지대의 생태통로를 파악하고 보호하는 데 기여할 수 있을 것으로 기대된다.
도농복합시는 1995년 지방자치제가 본격 시행되면서 주민 편의를 증진하고, 도시와 농촌 지역의 균형발전을 목적으로 설치되었다. 본 연구는 우리나라 전체 54개 도농복합시를 대상으로 도시 스프롤 측면에서 도시공간구조를 분석하고자 하였다. 이를 위해 밀도 기반의 도시 스프롤 측정 지수를 적용하여 2000년, 2010년, 2020년 도농복합시의 도시 스프롤을 인구밀도 및 고용밀도의 측면에서 탐색하였다. 분석 결과, 도농복합시의 인구 스프롤은 전반적으로 증가한 반면, 고용 스프롤은 감소하는 경향을 보였다. 그리고 도시 규모별 도농복합시의 도시 스프롤은 차별화되어 진행되었음을 확인하였다.
This study aims to distinguish between various Ethiopian durum wheat varieties based on their genetic identity using chemical and morphological characterization of seeds. Combinatorial employment of five chemical tests on seeds showed marked qualitative variation among the test varieties, with high discriminatory potential noted for the standard phenol test, followed by the modified phenol and iodide tests. The modified phenol test was instrumental in further discriminating between the varieties that were not identified using the standard phenol test. Unlike the iodide and phenol tests, the NaOH and KOH tests did not show significant variation among the varieties. These results underscore the efficacy of phenol and iodide tests in differentiating between durum wheat varieties. Although the morphological traits were advantageous in seed characterization, they lacked discriminatory power compared with that of the chemical tests. This study concludes that a single test is inadequate for varietal discrimination; rather, a combination of chemical tests can augment the discriminatory potential.