• East Asian mathematical journal
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• 제37권1호
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• pp.41-77
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• 2021

Let M be a semi-invariant submanifold of codimension 3 with almost contact metric structure (��, ξ, η, g) in a complex space form Mn+1(c), c ≠ 0. We denote by Rξ = R(·, ξ)ξ and A(i) be Jacobi operator with respect to the structure vector field ξ and be the second fundamental form in the direction of the unit normal C(i), respectively. Suppose that the third fundamental form t satisfies dt(X, Y ) = 2��g(��X, Y ) for certain scalar ��(≠ 2c)and any vector fields X and Y and at the same time Rξ is ��∇ξξ-parallel, then M is a Hopf hypersurface in Mn(c) provided that it satisfies RξA(1) = A(1)Rξ, RξA(2) = A(2)Rξ and ${\bar{r}}-2(n-1)c{\leq}0$, where ${\bar{r}}$ denotes the scalar curvature of M.

• Kyungpook Mathematical Journal
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• 제62권1호
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• pp.133-166
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• 2022

Let M be a semi-invariant submanifold with almost contact metric structure (𝜙, 𝜉, 𝜂, g) of codimension 3 in a complex space form M_n+1(c) for c ≠ 0. We denote by S and R_𝜉 be the Ricci tensor of M and the structure Jacobi operator in the direction of the structure vector 𝜉, respectively. Suppose that the third fundamental form t satisfies dt(X, Y) = 2𝜃g(𝜙X, Y) for a certain scalar 𝜃 ≠ 2c and any vector fields X and Y on M. In this paper, we prove that if it satisfies R_𝜉𝜙 = 𝜙R_𝜉 and at the same time S𝜉 = g(S𝜉, 𝜉)𝜉, then M is a real hypersurface in M_n(c) (⊂ M_n+1(c)) provided that $\bar{r}-2(n-1)c{\leq}0$, where $\bar{r}$ denotes the scalar curvature of M.

• 한국축산시설환경학회지
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• 제16권2호
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• pp.129-134
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• 2010

본 실태조사는 분만돈방과 분만틀 사용실태를 조사함으로써 분만돈의 동물복지 수준을 향상시킬 수 있는 대체 사육시설을 개발하는데 필요한 기초자료를 확보하기 위해 실시되었다. 분만돈방은 크게 형태별로 수직형 분만돈방과 사선형 분만돈방 두 가지로 구분되었으며, 분만틀은 압사방지 바(Bar)의 형태를 기준으로 수평형(Horizontal bar) 분만틀, 수직형(Vertical bar) 분만틀로 구분되었다. 기타 시설물에 대한 조사결과, 조사농가의 전체가 니플형 급수시설을 사용하고 있었으며, 약 80%가 습식급이기를 사용하고 있었고, 조사 농가의 약 40%가 전체틈바닥, 약 60%가 부분 틈바닥이었으며, 분만돈 두당 최소 $3.9\;m^2$ 이상의 면적을 제공하고 있었다. 국내의 다양한 사육시설과 환경으로 인하여 일괄적인 구조개선이나 새로운 사육시설의 적용은 쉽지 않을 것으로 판단되지만 이러한 국내 양돈농가의 실태조사 자료들을 동물복지 수준을 향상시킬 수 있는 대체 사육시설을 개발하는데 좋은 기초자료가 될 것이라 생각한다.

• 한국독어학회지:독어학
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• 제9집
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• pp.1-21
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• 2004

Die sogenannten verba pura bilden eine Teilmenge der germanischen starken Verben der VII. KLasse. Sie sind auf einsilbige langvokalisch auslautende Wurzeln des Vorurgermanischen $zur\"{u}ckzufuhren$: z. B. ${\ast}kn\bar{e}an$ 'erkennen', ${\ast}m\bar{e}an$ '$m\"{a}hen$', ${\ast}bl\bar{o}an$ $'bl\"{u}hen'$, ${\ast}m\bar{o}an$ $'qu\"{a}hlen'$. Um den Begriff der verba pura genau zu $erkl\"{a}ren$, stellt man diesen Verben die sogenannten verba impura $gegen\"{u}ber$, bei denen auf die lang Wurzelvokale urgerm. ${\ast}-\bar{e}-$ und ${\ast}-\ber{o}-$ ein Konsonant folgl: z.. B. urgerm. ${\ast}l\bar{e}tan$ (got. \etan) 'lassen', ${\ast}hw\bar{o}pan$ (got. hvopan) 'sich $r\"{u}hmen$'. Die germanischen starken Verben der VII. Klasse hat die $st\"{a}rksten$ Umgestaltungen mitgemacht, und zwar die verba pura noch mehr. In diesem Aufsatz untersuchte ich die $Gr\"{u}nde$ ihrer Umgestaltungen im germanischen Verbalsystem. Danach wird der Vorgang erschlossen, wie die verba pura in Ahd. zu den schwachen Verben I $\"{u}bertraten$. Dabei werden die folgenden Punkte besonders behandelt: Hatten die $fr\"{u}hzeitigen${\;}Pr\"{a}sensformen$ der verba pura -i-, das aus -jan herausgeht? Wenn nein, wie haben die verba pura zur schwachen Flexion $\"{u}bertraten$? Warum konnten die verba pura wie die anderen redupliziernden Verben in Ahd. nicht zu ablautenden Verben $\"{u}bergehen$?

• Journal of Welding and Joining
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• 제3권1호
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• pp.22-31
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• 1985

Hot straining embrittlement is one of the most important factors which cause the brittle fracture initiation even in the service temperature in the case of mild steel and high tensile steel. Therefore it is necessary to analyze thoroughly the hot straining embrittlement occurred in weld HAZ of the structural steels. The behaviors of plastic deformation and fracture toughness at the notch tip of the hot strained weld HAZ in structural steels (SB 41 KS, SA 588-Grade A ASTM) have been studied by the recrystallization technique and crack opening displacement (COD) test method. The obtained results are summarized as follows; 1. The plastic zone is formed at the notch tip of weld HAZ owing to nomotonic and cyclic hot stran, and the maximum plastic strain increases with the accumulated hot straining amounts. 2. The distribution of the effective strain at the plastic deformed zone in HAZ can be determined as follows; (.epsilon. over bar $_{p}$ )$_{\chi}$=.epsilon. over bar $_{cr}$ ( $R_{/chi}$/.chi.)$^{m}$ where, .epsilon. over bar $_{cr}$ : (SB 41; .epsilon. over bar $_{cr}$ = 0.2, SA 588; .epsilon. over bar $_{cr}$ = 0.1) 3. The embrittlement of weld HAZ in SB 41 and SA 588 is influenced by hot strain, and the degree of embrittlement becomes deeper with hot straining amounts. 4. The embrittlement of weld HAZ of SB 41 is not influenced by the hot straining amounts until .epsilon. over bar $_{max}$ = 0.36, $R_{\chi}$ = 0.065mm, however the embrittlement of structure in SA 588 is considerably influenced even by a small quantity of the hot straining amounts.s.

• 전기학회논문지
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• 제67권3호
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• pp.467-473
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• 2018

R-Bar(Overhead Rigid Conductor system) is being developed for the high-speed in Europe because it has an advantage of cross section area reduction of tunnel compared with OCS (Overhead Catenary Line). Because there are lots of underground sections and mountains in korea, it is necessary to develop the R-Bar for a high-speed line. In this study, a method on speed-up of transition section between OCS and R-Bar is proposed. The commercial program, DAFUL, is used to predict a dynamic characteristics between Overhead Line and pantograph. The program is evaluated according to EN 50318 which is the European Norm for evaluation of the program. Using the evaluated modeling and method, a method for the max. speed of 250 km/h of transition section is proposed.

• 열처리공학회지
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• 제5권1호
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• pp.13-22
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• 1992

The thermal stability of duplex high Mn-steel structure have been investigated using 15%Mn~1.0~2.4%C steels which are composed of ${\gamma}$-and ${\theta}$-phases in the range of temperature from 900 to $1100^{\circ}C$, and time from 50 to 300h. The results are as follows ; 1) The grain growth in single-phase region proceeds by grain boundary migration and the relation between mean radius $\bar{r}$ and annealing time t is described as follows ; $\bar{r}^2-{\bar{r}_0}^2=k_0{\cdot}t$ 2) The grain growth of duplex, (${\gamma}+{\theta}$), strucrure is slower than that single phase because the chemical composition of ${\gamma}$-and ${\theta}$-phases differs esch others. 3) The grain of (${\gamma}+{\theta}$) duplex structure grow slowly in a mode of Ostwald ripening. Because grain boundaries of ${\gamma}$-phase migrate under a restriction of pinning by ${\theta}$-phases. 4) In the duplex structures. the dispersed structures change to the dual-structures, as the volume fraction of the dispersed second-phase increase. Consequently, the growth-law, which is controlled by boundary-diffusion change to that of the volume diffusion-mechanism.

• 한국전기전자재료학회논문지
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• 제32권6호
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• pp.507-511
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• 2019

The purpose of an electric railway system contact wire is to supply electric energy to trains through a contacted pantograph. This energy is then converted into mechanical energy. Recent developments in overhead contact lines include the increase in the tension force up to 34 kN according to train speeds that reach up to 400 km/h with a verified safety. Rigid conductor catenary (R-Bar) for high speeds of up to 250 km/h have been developed in tunnels to save on construction costs. This is significant because minor defects in R-bars in aspects, such as height and stagger affect installation conditions. In this study, we propose the use of a detector that measures the static characteristics to reduce the R-bar installation errors. This detector has been developed to measure the height and stagger of the contact wire using video images.

• Journal of applied mathematics & informatics
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• 제37권1_2호
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• pp.23-35
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• 2019

Self-reciprocal polynomials are important because it is possible to specify only half of the coefficients. The special case of the self-reciprocal polynomial, the maximum weight polynomial, is particularly important. In this paper, we analyze even cell 90/150 cellular automata with linear rule blocks of the form < $a_1,{\cdots},a_n,d_1,d_2,b_n,{\cdots},b_1$ >. Also we show that there is no 90/150 CA of the form < $U_n{\mid}R_2{\mid}U^*_n$ > or < $\bar{U_n}{\mid}R_2{\mid}\bar{U^*_n}$ > whose characteristic polynomial is $f_{2n+2}(x)=x^{2n+2}+{\cdots}+x+1$ where $R_2$ =< $d_1,d_2$ > and $U_n$ =< $0,{\cdots},0$ >, and $\bar{U_n}$ =< $1,{\cdots},1$ >.

• 한국공간구조학회지
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• 제5권4호
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• pp.15-20
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• 2005