http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
한국산 좀개구리밥속(개구리밥과)의 분류학적 실체에 대한 재고
김용인,심상인,박진희 한국환경생태학회 2017 한국환경생태학회지 Vol.31 No.4
좀개구리밥속(Lemna L.)이 속하는 개구리밥과(Lemnaceae Martinov)는 다년생 초본으로, 5속 약 40종이 극 지방을 제외한 전세계에 널리 분포한다. 좀개구리밥속 식물은 피자식물 중 크기가 가장 작고 형태가 단순한 부유성의 단자엽 수생식물로 영양번식이 매우 빨라 약 3일마다 배로 증가하는 특성을 보여 수환경 오염 피해 평가나 독성 시험에 이용되는 등 유용성이 큰 식물로 평가되고 있다. 우리나라의 좀개구리밥속 종 분포에 대해서는 학자별로 다른 학명을 쓰기도 하였으나 1종이 존재하는 것으로 여러 학자들이 보고해 왔다. 본 연구에서는 한국산 좀개구리밥속 식물에서 관찰된 외부 형태적 변이에 주목하여, 2종 이상일 가능성을 염두에 두고 그 실체를 규명하고자 분자계통학적 방법으로 연구를 수행하였다. 전국적으로 분포하는 좀개구리밥속 식물 37개체군의 엽록체 DNA atpF-H 구간 염기서열을 결정한 결과, 염기서열 길이는 463-483bp인 것으로 확인되었고 37개체군의 염기서열을 정렬한 길이는 488bp였으며, 47개 뉴클레오티드지점에서 변이가 나타났다. 한국산 좀개구리밥속 식물 37개체군의 엽록체 DNA atpF-H 구간 염기서열은 크게 두 개의 유형으로 나누어졌으며, 계통분석 결과에서도 최대절약계통수에서 두 개의 clade로 나누어졌고, 그 중 한 clade는 두 개의 subclade로 다시 나누어졌다. 이는 현재까지 우리나라에 1종만 분포한다고 알려진 것과는 다른 결과로 최소 2개 이상 분류군(L.aequinoctialis, L.minor)이 국내에 분포한다는 것을 의미한다. Duckweed family (Lemnaceae Martinov), including the genus Lemna L., is a typical floating aquatic perennial plant, and about five genera and 40 species in the family are in wide distribution around the world except the polar regions. The genus Lemna is the smallest and the simplest plant among the angiosperms. It has a characteristic of doubling every three days with fast vegetative propagation, which helps the organisms to increase in rapid growth. As such, the plant is ideal for environmental pollution assessment and toxicity test. Although taxonomists and scholars have used different scientific names for the species, many of them have agreed that there is only one member of species of the genus Lemna in Korea. Paying attention to the external morphological variation observed in the Korean genus Lemna, we conducted a molecular phylogenetic analysis to identify the entity of the Korean Lemna species and to investigate the possibility of two or more members of the species existing in Korea. We determined and aligned the DNA sequences of the atpF-H region of the chloroplast DNA in 37 populations of the nationally distributed Lemna species. The results showed that the sequence length of the cp DNA atpF-H region was 463-483 bp, the length of the aligned sequences was 488 bp, and the number of variation site in nucleotide sequences was 47. There were two types of aligned sequences of the cp DNA atpF-H region from 37 populations of Lemna species in Korea. The maximum parsimony analysis revealed that the Korean Lemna consists of two clades, and one of them had two subclades. The results suggest that, contrary to the general understanding, at least two taxa (L.aequinoctialis, L.minor) exist in Korea.
SUFFICIENT CONDITIONS FOR THE INTERSECTION PROPERTY IN GENERALIZED LI¶ENARD SYSTEMS
김용인 한국수학교육학회 2011 純粹 및 應用數學 Vol.18 No.3
Some new results on the intersection property of all nonzero solutions of a class of planar systems of Li¶enard type with vertical isoclines are obtained. The results of this paper generalize some previous results on this ¯eld.
SOLVABILITY FOR SOME DIRICHLET PROBLEM WITH P-LAPACIAN
김용인 한국수학교육학회 2010 純粹 및 應用數學 Vol.17 No.3
We investigate the existence of the following Dirichlet boundary value problem (ju0jp¡2u0)0 + (p ¡ 1)[®ju+jp¡2u+ ¡ ¯ju¡jp¡2u¡] = (p ¡ 1)h(t);u(0) = u(T) = 0;where p > 1; ® > 0; ¯ > 0 and ®¡1p + ¯¡1p = 2; T = ¼p=®1p ; ¼p = 2¼p sin(¼=p) and h 2 L1(0; T). The results of this paper generalize some early results obtained in [8] and [9]. Moreover, the method used in this paper is elementary and new.
ESTIMATION OF DIFFERENCE FROM HÄOLDER'S INEQUALITY
김용인 한국수학교육학회 2010 純粹 및 應用數學 Vol.17 No.2
We give an upper bound for the estimation of the di®erence between both sides of the well-known HÄolder's inequality. Moreover, an upper bound for the estimation of the difference of the integral form of HÄolder's inequality is also obtained. The results of this paper are natural generalizations and re¯nements of those of [2-4].
SPATIALLY HOMOGENEOUS GLOBAL PRICE DYNAMICS ON A CHAIN OF LOCAL MARKETS
김용인 한국수학교육학회 2009 純粹 및 應用數學 Vol.16 No.2
The main purpose of this paper is to use the methods of Lattice Dynamical System to establish a global model, which extends the Walrasian evolutionary cobweb model in an independent single local market to the global market evolution over an infinite chain of many local markets interacting each other through a diffusion of prices between them. For brevity of the model, we assume linear decreasing demands and quadratic supplies with naive predictors, and investigate the spatially homogeneous global price dynamics and show that the dynamics is topologically conjugate to that of well-known logistic map and hence undergoes a period-doubling bifurcation route to chaos as a parameter varies through a critical value.
TRAVELING WAVE GLOBAL PRICE DYNAMICS OF LOCAL MARKETS WITH LOGISTIC SUPPLIES
김용인 한국수학교육학회 2010 純粹 및 應用數學 Vol.17 No.1
We employ the methods of Lattice Dynamical System to establish a global model extending the Walrasian evolutionary cobweb model in an independent single local market to the global market evolution over an infinite chain of many local markets with interaction of each other through a diffusion of prices between them. For brevity of the model, we assume linear decreasing demands and logistic supplies with naive predictors, and investigate the traveling wave behaviors of global price dynamics and show that their dynamics are conjugate to those of H´enonmaps and hence can exhibit complicated behaviors such as period-doubling bifurcations, chaos, and homoclic orbits etc.
GLOBALIZATION OF A LOCAL MARKET DYNAMICS ONTO AN INFINITE CHAIN OF LOCAL MARKETS
김용인 한국수학교육학회 2009 純粹 및 應用數學 Vol.16 No.1
The purpose of this paper is to extend and globalize the Walrasian evolutionary cobweb model in an independent single local market of Brock and Hommes ([3]), to the case of the global market evolution over an infinite chain of many local markets interacting each other through a diffusion of prices between them. In the case of decreasing demands and increasing supplies with a weighted average of rational and naive predictors, we investigate, via the methods of Lattice Dynamical System, the spatial{temporal behaviors of global market dynamics and show that some kind of bounded dynamics of global market do exist and can be controlled by using the parameters in the model.
STATIONARY GLOBAL DYNAMICS OF LOCAL MARKETS WITH QUADRATIC SUPPLIES
김용인 한국수학교육학회 2009 純粹 및 應用數學 Vol.16 No.4
The method of Lattice Dynamical System is used to establish a global model on an infinite chain of many local markets interacting each other through a diffusion of prices between them. This global model extends the Walrasian evolu-tionary cobweb model in an independent single local market to the global market evolution. We assume that each local market has linear decreasing demands and quadratic supplies with naive predictors, and investigate the stationary behaviors of global price dynamics and show that their dynamics are conjugate to those of Hénon maps and hence can exhibit complicated behaviors such as period-doubling bifurcations, chaos, and homoclic orbits etc.
EXISTENCE OF HOMOCLINIC ORBITS FOR LI¶ENARD TYPE SYSTEMS
김용인 한국수학교육학회 2010 純粹 및 應用數學 Vol.17 No.4
We investigate the existence of homoclinic orbits of the following sys-tems of Lienard type: a(x)x0 = h(y)¡F(x); y0 = ¡a(x)g(x), where h(y) = mjyjp¡2y with m > 0 and p > 1 and a; F; g are continuous functions such that a(x) > 0 for all x 2 R and F(0) = g(0) = 0 and xg(x) > 0 for x 6= 0. By a series of time and coor-dinates transformations of the above system, we obtain su±cient conditions for the positive orbits of the above system starting at the points on the curve h(y) = F(x)with x > 0 to approach the origin through only the ¯rst quadrant. The method of this paper is new and the results of this paper cover some early results on this topic.