Most existing theories on ship waves and wave resistance are based on the perturbation of the flow field by a small pararr.eter which specifies the slenderness of the ship hull. Since however, ship hulls in practice are neither so slender nor thin enough to secure the validity of the linearized theory, the agreen:ent between the theoretical prediction and the experimental result is not generally satisfactory. The author pointed out that the contribution by the non-linear term in the free surface condition can be represented by sorr.e source distribution over the still water plane. This paper leads to a forrr.ula for the wave resistance of not slender ships at low Froude nurr.bers. and deals with the asynptotic expression. As a nurr.erical example, the wave resistance of Wigley model is calculated, and the result is compared with experimental values. It is concluded that the wave resistance coefficient varies in the rate of Fn6 at low speed limit in general. A comparison with the result derived from the linearized free surface condition shows that the non-linearity of the free surface is irr portant at low speed.

실험포장에 있어서의 도열병발생상은 잎도열병의 발생량이 경한데 비해 통일계품종의 이삭도열병은 결발형이었고 일본형품종의 그것은 역시 경하였다. 시비수준간의 도열병 발생량의 차이는 통일계품조의 경우 잎도열병에서는 뚜렷하게 나타났으나 이삭도열병에서는 뚜렷하지 않았다. 지엽(n-1)이나 그 아래에 있는 n-2엽, n-3엽 등에서 강우수나 엽상의 노적수에서 만들어지 포자현탁액이 엽신에서 엽초의 봉합부를 거쳐 엽초내에 침투하고 수에 접착한 다음 감염을 일으키는 것으로 판명되었다. 자연환경하에서나 인공환경아래에서도 엽초내에 포자현탁액을 주입하면 수의 각부분이 감염되었으며 자연환경아래에서 생육중인 수도의 수잉기엽초내에는 도열병균과 그밖에 여러가지 진균의 포자가 검출되어 수잉기엽초내에서의 수열병 감염이 가능한 것으로 판명 되었다. 실험포장에서의 통일계품종의 이삭도열병의 발병은 내외이며 이 중에 수잉기 감염이 출수후 감염보다 훨씬 많으며 0.5N 시비구에서는 배, 1.0구에서는 배, 1.5N 구에서는 배 가량이 많았다. 한편 일본형수도품종에 있어서는 이삭도열병의 감염율은 에 지나지 않았다.

통일품종의 도열병저항성 유전자구성과 저항성의 유전에 관련하는 이들 유전자의 상호관계를 구명하기 위하여 통일품종과 5개의 이병성 재래품종, 밀성, 팔굉, 신 2호, 중국 4.호 및 관동 89호 등을 교잡하여 얻어진 및 집단에 도열병균주 E-7과 100-14를 각각 주사 접종하여 그들의 분리비를 Chi-square test하였다. 1. 유전자분석에 사용된 도열병균주 E-7, T-1 및 100-14sms 일본판별품종에 의하여 각각 C-3, T-1 및 C-5로 동정되었다. 2. 식물체는 접종균주에 대하여 저항성 모품종과 동일한 수준의 저항성을 나타냈으며 이것은 도열병 저항성이 이병성에 대하여 완전우성임을 시사한 것으로 보였다. 3. 집단에서는 접종균주 E-7과 100-14에 대하여 저항성과 이병성의 분리비가 각각 3:1로 나타나 이들 균주에 대한 토일의 저항성은 단성유전을 하는 것으로 보였다. 4. 접종균주 E-7에 대하여 저항성인 집단에 100-14 균주를 2차로 접종한 저항성과 이병성이 3:1로 분리되어 이 두 균주에 대한 통일의 저항성은 서로다른 별개의 유전자에 의하여 발견되는 것으로 보였다. 5. 본 실험의 결과를 종합하면 접종균주 T-1, E-7 및 100-14에 대한 저항성은 서로 다른 유전자에 의하여 지배되므로 통일품종은 적어도 3개 이상의 도열병 저항성 유전자를 갖는 것으로 추정되었다.

코발트는 합금산업에서 발생되는 산업 폐기물과 산성광산배수로 자연에 유입될 수 있으며 또한 고준위 방사성 폐기물을 구성하는 방사성 핵종(60Co)기도 하다. 스멕타이트는 이들을 흡착 격리하는데 유용하게 사용될 수 있는 광물이다. 본 연구에서는 기존에 특성이 잘 알려진 스멕타이트 중 The Clay Mineral Society (CMS)의 source clay인 Cheto-type montmorillonite (Cheto-MM)를 사용하여 가열에 의한 탈수 전후 광물의 층간수 존재 여 부에 따른 흡착 자리가 코발트 흡착에 미치는 영향을 평가하고, 흡착 속도 및 등온흡착식 모델을 적용하여 Cheto- MM의 코발트에 대한 흡착 기작을 연구하였다. 본 연구 결과 탈수 및 이에 따른 층간 수축에 의해 흡착 특성이 달 라지는 것을 확인할 수 있었으며, 코발트는 Cheto-MM의 층 모서리 자리에서의 흡착이 약 38%, 층간 내부에서의 흡착이 약 62%를 차지하는 것으로 확인되었고 Cheto-MM의 코발트 흡착은 층간 내부에 의한 영향이 큰 것으로 판 단된다. 이러한 흡착에 있어 흡착 속도 모델을 적용한 결과, Cheto-MM의 코발트 흡착 속도는 pseudo-second-order 모델로 설명되며 농도에 따른 흡착은 Langmuir 등온흡착 모델로 가장 잘 설명되었다. 본 연구는 몬모릴로나이트 의 흡착 자리에 따른 코발트의 흡착 양상에 대한 기본지식을 제공하고, 추후 고준위 방사성 폐기물 처분장에서의 스멕타이트의 흡착 거동을 예측하는데 유용하게 사용될 수 있을 것으로 생각된다.

This study used a batch DAF (dissolved air flotation) jar tester to evaluate the algae removal efficiency of alum and PAC coagulants during coagulation, flocculation, and flotation. Optimal coagulant dosages were 0.06 ~ 0.15 mL/L (12.0 ~ 26.0 mg Al/L,17%), 0.08 ~ 0.20 mL/L (10.0 ~ 24.0 mg Al/L, 12%), 0.25 ~ 0.30 mL/L (25.0 ~ 30.0 mg Al/L, 10%) for PAC, and 3.0 ~ 5.0 mL/L (81.0 ~ 135.0 mg Al/L, 2.7%) for alum. Turbidity of treated water was 1.0 ~ 2.0 NTU in optimal coagulation, flocculation, and flotation conditions for the four coagulants types. The amount of coagulant injected tended to decrease with increasing Al content in the coagulant, as follows : 17% PAC < 12% PAC < 10% PAC < 2.7% alum. Turbidity removal efficiencies were in the order of 12% PAC (93.6%) > 10% PAC (92.7%) > 17% PAC (91.3%) > 2.7% Alum (88.1%).

Tropical cyclones (TCs) over the western North Pacific (WNP) mainly occur during June-October, and result in significant casualties and damages to property in East Asian countries (e.g., Korea, Japan, Taiwan, and China, etc.). Although the total number of TCs that occurred over WNP was similar to normal years, the numer of TCs that affected Korea in August and September 2019 was 3 times higher than with the same number of TCs in July. Therefore, this study examined why more TCs migrated into Korea in 2019 through analyzing four environmental conditions: steering flow, geopotential height at 500 hPa, vertical wind shear (VWS), and sea surface temperature (SST). Results showed that the tracks of TCs were significantly associated with steering flows from July to September. Furthermore, weaker VWS and warmer SST were distributed near the tracks of TCs during August and September, whereas strong VWS and lower SST were dominant in July. The environmental conditions in August and September were favorable for maintaining and developing TCs, explaining why more typhoons have affected Korea during August and September in 2019.

마그네슘(magnesium; Mg)은 탄산염 광물이 침전된 과거의 환경 조건을 유추하기 위한 지화학 지시자로 활용되어오고 있다. Mg를 신뢰도 높은 지화학 지시자로 활용하기 위해서는 Mg의 화학종을 근거로 한 Mg의 광물 함유 기작이 반드시 규명되어야만 하며, 관련 실험 연구들은 주로 고해상도(high resolution)의 방사광가속기(synchrotron) X-선 흡수 분광(X-ray absorption spectroscopy; XAS) 기법을 통해 Mg의 화학종을 유추한다. 그러나, Mg가 미량 함유된 광물의 XAS 스펙트럼 해석의 높은 불확실성 때문에 화학종 유추가 어려운 경우가 많다. 양자역학 밀도범함수이론(density functional theory; DFT)은 결정구조에 대한 흡수 스펙트럼을 예측할 수 있기 때문에, XAS 스펙트럼 해석의 불확실성을 줄일 수 있다. 이번 논문에서는 DFT 기반의 제일원리 내각 준위 분광법(ab initio core-level spectroscopy method)을 통해 Mg 규산염 및 (수)산화광물에 대한 Mg K-edge 흡수 스펙트럼을 계산하여 Mg의 배위 결합 환경을 나타내는 구조 인자와의 상관관계를 분석하였다. 계산 결과, DFT 계산으로 얻은 Mg 규산염 및 (수)산화물의 이론 Mg K-edge 흡수 스펙트럼은 기존 XAS 실험으로 얻어진 스펙트럼의 주요 형태를 상당 부분 재현해낼 수 있었다. 계산으로 얻은 광물의 제일원리 Mg K-edge 흡수 스펙트럼의 흡수-끝(absorption edge)과 평균 Mg―O 결합거리 및 Mg 유효배위수를 비교 분석한 결과, 약한 양의 상관관계를 보여주었다. 이번 연구 결과는 DFT 계산이 다양한 광물 내 Mg의 화학종에 대한 표준 스펙트럼 세트를 제공할 수 있는 강력한 도구임을 보여주며, 추후 탄산염 광물에 함유된 정확한 Mg의 화학종을 동정 하는데 DFT 계산이 큰 역할을 할 수 있음을 제시한다.

The addressee honorification marker si-marked predicate in Korean must have an honorific vocative element in Spec-Voc in order for the unchecked feature of the addressee honorification marker si on Voc to be discharged in the Spec-head relation with the vocative element in Spec-Voc in the concept of Chomsky's (1995) Minimalist Program, which induces the addressee honorification at the speech level. The unchecked feature of the addressee honorification marker si-ess-upnita/sey-yo) percolates from T to Voc. At this point, VocP is above CP, which is why addressee honorification and impersonal subject honorification cannot appear in the embedded clause in Korean. Imperatives with quantificational subjects in English can exhibit, in addition to second person pronouns, third person pronouns as well. This is because a bound element exhibits either the person feature of the partitive phrase binding second or third person pronoun, or default third person value, which is against S. Park (2020).

In this study, an effective fluorescence pH sensor based on conjugated polyelectrolyte micelles (CPMs) was devised for detecting extremely acidic conditions. An amphiphilic coumarin derivative (CC12-N), a building block, was prepared, into which an ionizable amino group, aryl amine, was incorporated as a potential hydrophilic moiety. This monomer displays self-assembled micelle formation in extremely acidic pH ranges, giving a hydrophobic π-extended conjugated system at the inner part and hydrophilic functionality at the periphery, resulting in efficient fluorescence intensity enhancement. This new micelle-based fluorescence provides an efficient sensing platform for detecting very low pH values in the presence of competing substances.

Legged locomotion has high mobility on irregular surfaces by touching the ground at discrete points. Inspired by the creature’s legged locomotion, legged robots have been developed to explore unstructured environments. In this paper, we propose a modular crawler that can easily adjust the number of legs for adapting the environment that the robot should move. One module has a pair of legs, so the number of legs can be adjusted by changing the number of modules. All legs are driven by a single driving motor for simple and compact design, so the driving axle of each module is connected by the universal joint. Universal joints between modules enable the body flexion for steering or overcoming higher obstacles. A prototype of crawler with three modules is built and the driving performance and the effect of module lifting on the ability to overcome obstacles are demonstrated by the experiments.

본 연구는 2009 개정 교육과정이 적용된 2014학년도 대학수학능력시험부터 2019학년도까지 지속적으로 화학Ⅰ을 응시하는 학생이 감소하는 요인을 이를 지도하는 화학교사의 시각에서 탐색해 보았다. 이를 위해 1차로 27명의 화학교사를 대상으로 개방형 설문 조사를 실시하였다. 이후 이 설문 조사의 키워드 분석을 중심으로 7명의 화학교사를 대상으로 심층 면담을 진행하였다. 연구결과, 첫째로 일부 문항은 교육과정의 범위를 다소 벗어났다. 이러한 교육과정을 벗어난 문항은 학생들이 추가로 학습 부담을 느끼게 만드는 요인이 되었다. 둘째로, 화학Ⅰ 응시자들은 다른 과목에 비해 시험시간에 부담감을 느끼고 있었다. 지나친 계산을 요구하는 문항과 IQ-test와 같은 시간잡는 문항이 이러한 문제를 가속 시켰다. 셋째로, 화학Ⅰ을 다른 과목에 비해 최저등급을 받기 어려운 과목으로 인식하고 있었으며, 이러한 이유로 3～4등급의 학생들이 지속적으로 화학Ⅰ에서 다른 과목으로 응시과목을 변경하고 있었다. 화학Ⅰ의 응시자 감소에 대한 문제를 해결하기 위해서는 교육과정을 준수한 출제, 개념과 원리 중심의 문항 개발이 필요하다.

The purpose of this study is to provide the demand information about services (S/W) and infrastructure (H/W) for rural welfare and culture. The survey was conducted on the overall satisfaction level, the condition change, the importance-satisfaction level of each field and the top priority items for administrative agencies and rural residents. In the overall satisfaction level, administrative agencies responded more than 'normal' to all fields, but the overall satisfaction level was lower than 'normal' in the fields excluding the healthcare field in the case of rural residents. In terms of condition changes compared to the past five years, both administrative institutions and local residents evaluated the improvement. IPA analysis was conducted to identify the priority ranking of each field and it was found that emergency medical facilities in the healthcare field, infant day care facilities in the social welfare field, movie theaters in the culture field, lifelong education institutions and academy facilities in the education field and private sports facilities in the leisure and sports field were most needed, respectively. The results of this study are expected to be helpful in increasing the efficiency and presenting the improvement direction about the development policy of the rural culture and welfare.

잠기지 않은 수제 하류의 3차원 흐름구조에 Froude 수 변화가 미치는 영향을 알아보기 위한 수리모형 실험을 수행하였다. 3가지 Froude 수 조건에 대하여 초음파 유속계와 수위계를 이용하여 3차원 유속과 수심을 측정하였다. Froude 수는 시간평균유속 및 난류 특성의 전반적인 분포에는 크게 영향을 미치지 않는 것으로 나타났다. 그러나 Froude 수가 증가할수록 수제 위치의 흐름단면이 감소하고 제트 흐름 강도의 증가가 관찰되었다. 이 제트 흐름은 단면 내 최대 난류에너지 발생의 위치를 안쪽 제방으로 이동시키는 것으로 나타났다.

Two man-made carbon emissions, fossil fuel emissions and land use emissions, have been perturbing naturally occurring global carbon cycle. These emitted carbons will eventually be deposited into the atmosphere, the terrestrial biosphere, the soil, and the ocean. In this study, Simple Global Carbon Model (SGCM) was used to simulate global carbon cycle and to estimate global carbon budget. For the model input, fossil fuel emissions and land use emissions were taken from the literature. Unlike fossil fuel use, land use emissions were highly uncertain. Therefore land use emission inputs were adjusted within an uncertainty range suggested in the literature. Simulated atmospheric CO2 concentrations were well fitted to observations with a standard error of 0.06 ppm. Moreover, simulated carbon budgets in the ocean and terrestrial biosphere were shown to be reasonable compared to the literature values, which have considerable uncertainties. Simulation results show that with increasing fossil fuel emissions, the ratios of carbon partitioning to the atmosphere and the terrestrial biosphere have increased from 42% and 24% in the year 1958 to 50% and 30% in the year 2016 respectively, while that to the ocean has decreased from 34% in the year 1958 to 20% in the year 2016. This finding indicates that if the current emission trend continues, the atmospheric carbon partitioning ratio might be continuously increasing and thereby the atmospheric CO2 concentrations might be increasing much faster. Among the total emissions of 399 gigatons of carbon (GtC) from fossil fuel use and land use during the simulation period (between 1960 and 2016), 189 GtC were reallocated to the atmosphere (47%), 107 GtC to the terrestrial biosphere (27%), and 103GtC to the ocean (26%). The net terrestrial biospheric carbon accumulation (terrestrial biospheric allocations minus land use emissions) showed positive 46 GtC. In other words, the terrestrial biosphere has been accumulating carbon, although land use emission has been depleting carbon in the terrestrial biosphere.

간단한 규칙에도 불구하고 바둑은 인공지능 분야에서 가장 복잡한 전략적 보드게임 중의 하나이다. 몬테카를로 트리탐색(MCTS)은 최상우선 트리탐색 알고리즘으로 컴퓨터바둑 제작을 위해 사용되어 왔다. 저자는 9줄바둑판보다 작은 바둑판에서의 바둑게임 행위를 위해 MCTS를 활용하여 가장 유망한 첫 수를 찾고자 한다. 실험결과에 의하면 MCTS는 첫 수로 홀수형 바둑 판에서는 정중앙, 짝수형 바둑판에서는 중앙 부근에 착수하기를 선호하는 것으로 나타났다.

Background : Dry eyes are caused by highly increased osmolarity of tear film, inflammation, and apoptosis of the ocular surface. Polygonum cuspidatum is a herbaceous perennial plant of the genus Polygonum found in Asia and North America. However, the effects of P. cuspidatum aqueous extract (PCE) on hyperosmolarity-induced inflammation and apoptosis in human corneal epithelial cells have not been examined. Methods and Results : Hyperosmotic media induced human corneal epithelial cell (HCEC) cytotoxicity though increased inflammation, apoptosis, and oxidative stress. PCE treatment significantly inhibited expression of cyclooxygenase-2 and inflammatory cytokines (interleukin-6 and tumor necrosis factor-α), and activation of NF-κB p65 in hyperosmolar stress-induced HCECs. In addition, Hyperosmolarity-induced increase in BAX expression and activation of cleaved poly (ADP-ribose) polymerase and caspase 3 were attenuated in a concentration-dependent manner by PCE. PCE treatment restored anti-oxidative proteins such as Heme oxygenase-1 (HO-1), Superoxide dismutase-1 (SOD-1), and Glutathione peroxidase (GPx) in hyperosmolar stress-induced HCECs. Conclusion : PCE protected against hyperosmolar stress-induced inflammation, apoptosis, and oxidation by inhibiting expression of COX-2, BAX, MMP9; activation of NF-κB, caspase 3, and PARP; and increasing expression of MUC4 and anti-oxidative proteins. Overall, our data provide insight into the protective effects of PCE as a candidate for eye health.

Background : Development of new real-time PCR diagnosis method for simultaneous diagnosis of Cylindrocarpon destructans and Fusarium solani, causative fungi of ginseng root rot disease. C. destructans and F. solani are known to be the major pathogens of ginseng root rot disease. Root rot caused by these pathogens is a disease that is difficult to control because the disease progresses slowly and it is difficult to diagnose early and even when symptoms of plant seeding are present, the disease is already spread in the roots. Diagnostic methods to detect the presence or absence of ginseng roots rot fungi in soil before ginseng cultivation are currently being used as a method for controlling. However, commercialized soil extraction kits and PCR diagnostics have cost, diagnostic time, and single diagnostic problems, and need to develop new diagnostic methods. Methods and Results : Primers and probes in the beta-tubulin 2 gene were designed for species-specific detection. In silico analysis, the detection rate of C. destructans was 100% and the detection rate of F. solani was 95%. The multiplex real time PCR optimization conditions including the internal control were established. The analytical sensitivity using positive samples was 10 copies/㎕ for C. destructans and 10 copies/㎕ for F. solani. As a result of performance comparison test with conventional PCR diagnosis methods, it was confirmed that the developed multiplex real time PCR method has the same or better performance in terms of sensitivity. In the developed soil extraction kit, the extraction time was reduced and the extracted DNA quality was improved, compared to the used soil extraction kit. Conclusion : From the above results, we expect that the developed C. destructans / F. solani multiplex real time PCR diagnosis method and soil extraction kit will be useful for real-time monitoring of ginseng root rot pathogenic fungi in the soil of ginseng cultivation area and diagnosis of suitability of ginseng cultivation area.

Background : This study was carried out to introduce Atractylodes macrocephala as a new income element in Gangwon area and to develop the technology necessary for stable quality seedling production. Methods and Results : For the production of high quality seedlings of Atractylodes macrocephala, seedling growth characteristics were investigated according to the types of plug cell size and seedling raising period. Atractylodes macrocephala seeds were sown on February 14, 2018 in 72, 105, 128, 162, and 200 plug trays. The emergence period after sowing was March 2, and the final occurrence rate was 76.6 - 79.5%. The number of days of emergence took 18 to 20 days from sowing date. Growth of seedlings tended to be better with less number of plug trays, such as seedling height, seedling width, leaf length, leaf width and leaf number. On the other hand, roots (net formation) increased rapidly as the number of plug trays increased. After 60 days, the matured seedling rate was good at 75.5 ± 8.4% for the 200 plug tray and 72.5 ± 4.1% for the 162 plug tray. The net formation ratio of matured seedling was the best in 60 days of seeding in 162 plug trays. The rooting rate was 98.0 ± 2.1 - 99.3 ± 1.2% when seeded for 60 days or more regardless of the type of plug tray. Conclusion : In order to produce efficient and stable seedlings in the cultivation of Atractylodes macrocephala in Gangwon area, it was considered to be advantageous for 60 days of seedling settling in the plug trays of more than 162 and less than 200.