• 제목/요약/키워드: Tau

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The Order of Normal Form Generalized Hypersubstitutions of Type τ = (2)

  • Sudsanit, Sivaree;Leeratanavalee, Sorasak
    • Kyungpook Mathematical Journal
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    • 제54권3호
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    • pp.501-509
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    • 2014
  • In 2000, K. Denecke and K. Mahdavi showed that there are many idempotent elements in $Hyp_{N_{\varphi}}(V)$ the set of normal form hypersubstitutions of type ${\tau}=(2)$ which are not idempotent elements in Hyp(2) the set of all hypersubstitutions of type ${\tau}=(2)$. They considered in which varieties, idempotent elements of Hyp(2) are idempotent elements of $Hyp_{N_{\varphi}}(V)$. In this paper, we study the similar problems on the set of all generalized hypersubstitutions of type ${\tau}=(2)$ and the set of all normal form generalize hypersubstitutions of type ${\tau}=(2)$ and determine the order of normal form generalize hypersubstitutions of type ${\tau}=(2)$.

HOLOMORPHIC FUNCTIONS AND THE BB-PROPERTY ON PRODUCT SPACES

  • Boyd, Christopher
    • 대한수학회지
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    • 제41권1호
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    • pp.39-50
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    • 2004
  • In [25] Taskinen shows that if $\{E_n\}_n\;and\;\{F_n\}_n$ are two sequences of Frechet spaces such that ($E_m,\;F_n$) has the BB-property for all m and n then (${\Pi}_m\;E_m,\;{\Pi}_n\;F_n$) also has the ΒΒ-property. Here we investigate when this result extends to (i) arbitrary products of Frechet spaces, (ii) countable products of DFN spaces, (iii) countable direct sums of Frechet nuclear spaces. We also look at topologies properties of ($H(U),\;\tau$) for U balanced open in a product of Frechet spaces and $\tau\;=\;{\tau}_o,\;{\tau}_{\omega}\;or\;{\tau}_{\delta}$.

COEFFICIENT INEQUALITIES FOR ANALYTIC FUNCTIONS CONNECTED WITH k-FIBONACCI NUMBERS

  • Serap, Bulut;Janusz, Sokol
    • 호남수학학술지
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    • 제44권4호
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    • pp.521-534
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    • 2022
  • In this paper, we introduce a new class 𝓡kλ(λ ≥ 1, k is any positive real number) of univalent complex functions, which consists of functions f of the form f(z) = z + Σn=2 anzn (|z| < 1) satisfying the subordination condition $$(1-{\lambda}){\frac{f(z)}{z}}+{\lambda}f^{\prime}(z){\prec}{\frac{1+r^2_kz^2}{1-k{\tau}_kz-{\tau}^2_kz^2}},\;{\tau}_k={\frac{k-{\sqrt{k^2+4}}}{2}$$, and investigate the Fekete-Szegö problem for the coefficients of f ∈ 𝓡kλ which are connected with k-Fibonacci numbers $F_{k,n}={\frac{(k-{\tau}_k)^n-{\tau}^n_k}{\sqrt{k^2+4}}}$ (n ∈ ℕ ∪ {0}). We obtain sharp upper bound for the Fekete-Szegö functional |a3-𝜇a22| when 𝜇 ∈ ℝ. We also generalize our result for 𝜇 ∈ ℂ.

SOLVABILITY OF A THIRD ORDER NONLINEAR NEUTRAL DELAY DIFFERENTIAL EQUATION

  • Liu, Zeqing;Wang, Wei;Park, Jong Seo;Kang, Shin Min
    • 충청수학회지
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    • 제23권3호
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    • pp.443-452
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    • 2010
  • This work deals with the existence of uncountably many bounded positive solutions for the third order nonlinear neutral delay differential equation $$\frac{d^3}{dt^3}[x(t)+p(t)x(t-{\tau})]+f(t,x(t-{{\tau}_1}),{\ldots},x(t-{{\tau}_k}))=0,\;t{\geq}t_0$$ where ${\tau}>0$, ${\tau}_i{\in}{\mathbb{R}^+}$ for $i{\in}\{1,2,{\ldots},k\}$, $p{\in}C([t_0,+{\infty}),{\mathbb{R}^+})$ and $f{\in}C([t_0,+{\infty}){\times}{\mathbb{R}^k},{\mathbb{R}})$.

Ferrite/Rubber 0-3 Composite의 전파 흡수 특성 (Microwave absorbption characteristics of Ferrite/Rubber 0-3 Composites)

  • 김한근;박상하;조현철;사공건
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1992년도 하계학술대회 논문집 B
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    • pp.724-726
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    • 1992
  • In this paper, the permeability ($\mu_{\tau}'$, $\mu_{\tau}''$), dielectric constants($\varepsilon_{\tau}'$, $\varepsilon_{\tau}''$) and absorbption characteristics of Ferrite/Rubber 0-3 composites were investigated. The composite specimens were prepared by molding and curing the mixtures of matrix rubber and Ni-Zn ferrite powders which were synthesized by wet-direct method. The permeability ($u_{\tau}'$) of specimen was decreased from 2.58 to 0.7 in the range of 1$\sim$7(GHz) and kept constant 0.7$\sim$0.8 at higher than 7(GHz), the higher the frequency was, the less the valves of $u_{\tau}"$ was from 1.57 to 0.03. The optimum thickness of microwave absorber, utilizing the Smith chart, was 5(mm). The reflection loss shows over than 20(dB) from 5.5(GHz) to 7.5(GHz) at 5(mm) thickness and relative band width(B/fm) was about 30%.

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Review of the chemistry of first-generation Tau PET tracers

  • Farag, Ahmed Karam;Im, Changkeun;Kang, Choong Mo;Lee, Yong Jin
    • 대한방사성의약품학회지
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    • 제6권1호
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    • pp.27-38
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    • 2020
  • Alzheimer's disease (AD) is one of the challenging conditions that have no cure, yet early diagnosis can help to control the disease. PET imaging of tau has several advantages, such as being a noninvasive, safe diagnostic technique that correlates directly with the disease progression. Many tau tracers have been reported to date; however, the chemical scaffolds of them fall in a narrow chemical window, and none was approved yet as none is entirely selective and sensitive to tau. These problems are being solved as new tracers emerge constantly. In this report, the first-generation tau tracers such as [11C]PBB3, 2-arylquinoline (THK) series, [18F]T808, and [18F]AV-1451 ([18F]T807) are reviewed from an organic and radiochemistry perspective; thus the most effective chemical approach to synthesize these tracers is discussed. This would help to design novel tracers which can meet the challenges faced by the current tracers.

교각에 의한 하상세굴에 관한 실험적 연구 (Experimental Study on Local Bed Scour Due to Bridge Pier)

  • 이정규;정동원;이창해;육운수
    • 대한토목학회논문집
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    • 제14권6호
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    • pp.1349-1356
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    • 1994
  • 본 연구에서는 3가지 교각형상에 대하여 국부적 정지상세굴에 대한 실험결과를 분석하였다. 실험결과에 의하면 교각의 세굴은 $V/V_c=0.4{\sim}0.5$, $Fr_p{\fallingdotseq}0.2$일 때 시작되었고 상대세굴심은 유속비와 교각푸르드수와의 관계에서 선형적으로 증가하였다. 또한 상대세굴심은 ${\tau}_r$ < $10^{-4}$일 때는 선형적으로 증가하지만 ${\tau}_r$ > $10^{-4}$이 되면 일정해지는 경향을 가지며 모래의 기하표준편차(${\sigma}_g$)와 교각형상과도 깊은 관계가 있었다.

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표준공액구배법과 수정공액구배법을 이용한 2차원 열전도 문제의 역해석 (An Inverse Analysis of Two-Dimensional Heat Conduction Problem Using Regular and Modified Conjugate Gradient Method)

  • 최의락;김우승
    • 대한기계학회논문집B
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    • 제22권12호
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    • pp.1715-1725
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    • 1998
  • A two-dimensional transient inverse heat conduction problem involving the estimation of the unknown location, ($X^*$, $Y^*$), and timewise varying unknown strength, $G({\tau})$, of a line heat source embedded inside a rectangular bar with insulated boundaries has been solved simultaneously. The regular conjugate gradient method, RCGM and the modified conjugate gradient method, MCGM with adjoint equation, are used alternately to estimate the unknown strength $G({\tau})$ of the source term, while the parameter estimation approach is used to estimate the unknown location ($X^*$, $Y^*$) of the line heat source. The alternate use of the regular and the modified conjugate gradient methods alleviates the convergence difficulties encountered at the initial and final times (i.e ${\tau}=0$ and ${\tau}={\tau}_f$), hence stabilizes the computation and fastens the convergence of the solution. In order to examine the effectiveness of this approach under severe test conditions, the unknown strength $G({\tau})$ is chosen in the form of rectangular, triangular and sinusoidal functions.

A Quantitative Marine Traffic Safety Assessment of the Vung Tau Waterway

  • Nguyen, Xuan Thanh;Park, Youngsoo;Park, Jinsoo
    • 한국항해항만학회지
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    • 제36권9호
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    • pp.721-728
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    • 2012
  • Marine traffic safety of the Vung Tau Waterway, from port limit to Ganh Rai Gulf, plays a crucial role in the economic development of the important triangular economic zone in the south of Vietnam: Ho Chi Minh City, Dong Nai Province, Ba Ria-Vung Tau Province. This paper uses the IWRAP Mk2 program to assess marine traffic safety and shows that in the area there are three parts of fairway have highest risk of collision (from buoys No. 8-9 to buoys No. 1-2 of the Song Dinh fairway; from buoy No. 0 to buoys No. 8-9 and from buoys No. 6-9 to buoys No. 8-9A of the Sai Gon-Vung Tau fairway) and the two areas have highest risk of grounding (the Vung Tau coastline from Ganh Hao to Sao Mai and an area in the Ganh Rai Gulf). In addition, the result of a questionnaire survey on a group of Pilots shows that wind, current and rain/fog have considerable negative effect to ship handling of large vessels in this area. This paper's results will be used in the further research to discover solutions for improving marine traffic safety in the Vung Tau Waterway.

충격하중을 받는 유한평판의 3차원 동탄성이론에 의한 응력해석

  • 양인영;김선규;박정수
    • 오토저널
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    • 제13권5호
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    • pp.51-64
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    • 1991
  • In this paper, an attempt is made to analyze the impulsive stress directly underneath the concentrated impact point for a supported square plate by using the three-dimensional dynamic theory of elasticity and the potential theory of displacement (stress function) on the supposition that the load, F$_{*}$0 sin .omega.t, acted on the central part of it. The results obtained from this study are as follows: 1. The impulsive stress cannot be analyzed directly underneath the acting point of concenrated impact load in privious theories, but can be analyzed by using the three-dimensional dynamic theory of elasticity and the potential theory of displacement. 2. Theorically, with increasing the pulse width of applied load, it was possible to clarify that the amount of stress in the point of concentrated impact load was increased and that of stress per unit impulse was decreased. 3. The numerical inversion of laplace transformation by the use of the F.F.T algorithm contributes the reduction of C.P.U time and the improvement of the accuracy or results. 4. In this paper recommended, it is found that the approximate equation of impact load function P (.tau.) = A.tau. exp (-B.tau.), and P (.tau.) =0.85A exp (-B.tau.) sinC.tau. could actually apply to all impact problem. In compared with the experimental results, the propriety of the analytical method is reasonable.

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