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6432. Dipterocarpus obtusifolius exhibits enhanced photosynthetic capacity at high temperatures

Creator:
Norisada, M. and Kojima, K.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
Acacia, electron transport, Hopea, leaf temperature, photon-and CO2-saturated photosynthetic rate, and RuBP regeneration
Language:
Multiple languages
Description:
Seedlings planted on degraded lands experience high leaf temperature in daytime because of the lack of vegetation shading. The effect of high temperature on the photosynthetic capacity was investigated in Dipterocarpus obtusifolius Teijsm. ex Miq. and D. chartaceus Sym. seedlings planted on degraded sandy soils in southern Thailand. Neither species showed decrease in photosynthetic capacity at leaf temperature over 38 °C as compared to that at 28 °C. D. obtusifolius showed higher photosynthetic capacity at high temperatures. Enhanced photosynthetic capacity at high temperatures would be a key for high photosynthetic performance of D. obtusifolius planted on degraded sandy soils. and M. Norisada, K. Kojima.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

6433. Diracovy fermiony v grafenu: Relativita ve fyzice pevných látek?

Creator:
Orlita, Milan
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fyzika pevných látek, solid state physics, grafen, graphene, 539.2, 6, and 539
Language:
Czech
Description:
Bohatá rodina forem, ve kterých se vyskytuje uhlík, se nedávno rozrostla o nový a velmi zajímavý systém - grafen (angl. graphene). K obecně známému grafitu a diamantu a k nedávno objeveným a intenzivně studovaným uhlíkovým nanotrubkám a fullerenům tak přibyl první dvojdimenzionální alotrop uhlíku. Jeho příprava před několika lety odstartovala ve fyzice pevných látek nebývalou a stále trvající vlnu zájmu, srovnatelnou snad jen s objevem vysokoteplotní supravodivosti nebo kvantového Hallova jevu., Milan Orlita., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

6434. Direct adaptive control of unknown nonlinear systems using a new neuro-fuzzy method together with a novel approach of parameter hopping

Creator:
Theodoridis, Dimitris, Boutalis, Yiannis, and Christodoulou, Manolis
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
Neuro-Fuzzy systems, direct adaptive control, and parameter hopping
Language:
English
Description:
The direct adaptive regulation for affine in the control nonlinear dynamical systems possessing unknown nonlinearities, is considered in this paper. The method is based on a new Neuro-Fuzzy Dynamical System definition, which uses the concept of Fuzzy Dynamical Systems (FDS) operating in conjunction with High Order Neural Network Functions (F-HONNFs). Since the plant is considered unknown, we first propose its approximation by a special form of a fuzzy dynamical system (FDS) and in the sequel the fuzzy rules are approximated by appropriate HONNFs. The fuzzy-recurrent high order neural networks (F-RHONN) are used as models of the unknown plant, practically transforming the original unknown system into a F-RHONN model which is of known structure, but contains a number of unknown constant value parameters. The proposed scheme does not require a-priori experts' information on the number and type of input variable membership functions making it less vulnerable to initial design assumptions, is extremely fast and, hence, can be applied in several difficult and very demanding real-time engineering applications. and When the F-RHONN model matches the unknown plant, we provide a comprehensive and rigorous analysis of the stability properties of the closed loop system. Convergence of the state to zero plus boundedness of all other signals in the closed loop is guaranteed without the need of parameter (weights) convergence, which is assured only if a sufficiency-of-excitation condition is satisfied. The existence of the control signal is always assured by introducing a novel method of parameter hopping and incorporating it in weight updating law. Simulations illustrate the approximation superiority of the proposed scheme in comparison to other well established approaches. The applicability of the method is also tested on well known simulated nonlinear plants where it is shown that by following the proposed procedure one can obtain asymptotic regulation. Comparison is also made to simple RHONN controllers, showing that our approach is superior to the case of simple RHONN's.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

6435. Direct approach to mean-curvature flow with topological changes

Creator:
Pauš, Petr and Beneš, Michal
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
mean curvature flow, dislocation dynamics, and parametric approach
Language:
English
Description:
This contribution deals with the numerical simulation of dislocation dynamics. Dislocations are described by means of the evolution of a family of closed or open smooth curves Γ(t):S→R2, t≧0. The curves are driven by the normal velocity v which is the function of curvature κ and the position. The evolution law reads as: v=−κ+F. The motion law is treated using direct approach numerically solved by two schemes, i. e., backward Euler semi-implicit and semi-discrete method of lines. Numerical stability is improved by tangential redistribution of curve points which allows long time computations and better accuracy. The results of dislocation dynamics simulation are presented (e. g., dislocations in channel or Frank-Read source). We also introduce an algorithm for treatment of topological changes in the evolving curve.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

6437. Direct modeling of the gravitational field using harmonic series

Creator:
Pavel Novák
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, tíhový potenciál Země, topografie, mořská voda, gravitational potential, topography, sea water, Earth Gravitational Model, gravity reduction and stripping, ocean water, spherical harmonic series, 7, and 551
Language:
English
Description:
During the General Assembly of the European Geosciences Union in April 2008, the new Earth Gravitational Model 2008 (EGM08) was released with fully-normalized coefficients in the spherical harmonic expansion of the Earth's gravitational potential complete to degree and order 2159. EGM08 is based on inverse modeling methods that rely on data observed both on the Earth's surface and in space. Forward modeling equations based on Newtonian integrals can be converted into series forms that are compatible with the spherical harmonic description of the geopotential. Namely gravitational potentials of ocean water (fluid masses below the geoid) and topographical masses (solid masses above the geoid) can be formulated and evaluated numerically through spherical harmonic expansions. The potential constituents as well as their radial derivatives can be used for a step known in geodesy and geophysics as gravity field reduction or stripping. Reducing EGM08 for these constituents can help to analyze the internal structure of the Earth (geophysics) as well as to derive the Earth's gravitational field harmonic outside the geoid (geodesy)., Pavel Novák., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

6438. Direct product decompositions of bounded commutative residuated $\ell$-monoids

Creator:
Jakubík, Ján
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
bounded commutative residuated $\ell$-monoid, lattice, direct product decomposition, and internal direct factor
Language:
English
Description:
The notion of bounded commutative residuated $\ell $-monoid ($BCR$ $\ell $-monoid, in short) generalizes both the notions of $MV$-algebra and of $BL$-algebra. Let $\c A$ be a $BCR$ $\ell $-monoid; we denote by $\ell (\c A)$ the underlying lattice of $\c A$. In the present paper we show that each direct product decomposition of $\ell (\c A)$ determines a direct product decomposition of $\c A$. This yields that any two direct product decompositions of $\c A$ have isomorphic refinements. We consider also the relations between direct product decompositions of $\c A$ and states on $\c A$.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

6439. Direct product decompositions of infinitely distributive lattices

Creator:
Jakubík, Ján
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
direct product decomposition, infinite distributivity, and conditional α-completeness
Language:
English
Description:
Let α be an infinite cardinal. Let Tα be the class of all lattices which are conditionally α-complete and infinitely distributive. We denote by T'α the class of all lattices X such that X is infinitely distributive, α-complete and has the least element. In this paper we deal with direct factors of lattices belonging to T α - As an application, we prove a result of Cantor-Bernstein type for lattices belonging to the class T'α.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

6440. Direct solution of nonlinear constrained quadratic optimal control problems using B-spline functions

Creator:
Edrisi-Tabriz, Yousef and Lakestani, Mehrdad
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
optimal control problem, B-spline functions, derivative matrix, and collocation method
Language:
English
Description:
In this paper, a new numerical method for solving the nonlinear constrained optimal control with quadratic performance index is presented. The method is based upon B-spline functions. The properties of B-spline functions are presented. The operational matrix of derivative (Dϕ) and integration matrix (P) are introduced. These matrices are utilized to reduce the solution of nonlinear constrained quadratic optimal control to the solution of nonlinear programming one to which existing well-developed algorithms may be applied. Illustrative examples are included to demonstrate the validity and applicability of the technique.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

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