Lu System Research Articles

Comparative Analysis of the Chloroplast Genomes of Eight Species of the Genus Lirianthe Spach with Its Generic Delimitation Implications.

Based on Sima and Lu's system of the family Magnoliaceae, the genus Lirianthe Spach s. l. includes approximately 25 species, each with exceptional landscaping and horticultural or medical worth. Many of these plants are considered rare and are protected due to their endangered status. The limited knowledge of species within this genus and the absence of research on its chloroplast genome have greatly impeded studies on the relationship between its evolution and systematics. In this study, the chloroplast genomes of eight species from the genus Lirianthe were sequenced and analyzed, and their phylogenetic relationships with other genera of the family Magnoliaceae were also elucidated. The results showed that the chloroplast genome sizes of the eight Lirianthe species ranged from 159,548 to 159,833 bp. The genomes consisted of a large single-copy region, a small single-copy region, and a pair of inverted repeat sequences. The GC content was very similar across species. Gene annotation revealed that the chloroplast genomes contained 85 protein-coding genes, 37 tRNA genes, and 8 rRNA genes, totaling 130 genes. Codon usage analysis indicated that codon usage was highly conserved among the eight Lirianthe species. Repeat sequence analysis identified 42-49 microsatellite sequences, 16-18 tandem repeats, and 50 dispersed repeats, with microsatellite sequences being predominantly single-nucleotide repeats. DNA polymorphism analysis revealed 10 highly variable regions located in the large single-copy and small single-copy regions, among which rpl32-trnL, petA-psbJ, and trnH-psbA were the recommended candidate DNA barcodes for the genus Lirianthe species. The inverted repeat boundary regions show little variation between species and are generally conserved. The result of phylogenetic analysis confirmed that the genus Lirianthe s. l. is a monophyletic taxon and the most affinal to the genera, Talauma and Dugandiodendron, in Sima and Lu's system and revealed that the genus Lirianthe s. s. is paraphyletic and the genus Talauma s. l. polyphyletic in Xia's system, while Magnolia subsection Gwillimia is paraphyletic and subsection Blumiana polyphyletic in Figlar and Nooteboom's system. Morphological studies found noticeable differences between Lirianthe species in aspects including leaf indumentum, stipule scars, floral orientation, tepal number, tepal texture, and fruit dehiscence. In summary, this study elucidated the chloroplast genome evolution within Lirianthe and laid a foundation for further systematic and taxonomic research on this genus.

A modified synthetic aperture focusing algorithm used for transmission detection based on laser ultrasonics method

Compared with traditional ultrasonic nondestructive testing technology, the laser ultrasonics method (LU) has the advantages of high precision, non-contact, wide-band response, suitable for non-destructive testing (NDT) of materials having complex shapes or working in extreme environments such as the additive manufacturing (AM) process, etc. However, for a purely optical LU system, it is still limited by the poor reflection of rough/absorption surface of the material. In order to increase the signal-to-noise ratio (SNR) of the signal detected on the rough surface of a sample, and to overcome the limitation of the resolution restricted by half wavelength, a modified Synthetic Aperture Focusing Technique (SAFT) that can be used for internal defect detection of the material is proposed. The modified SAFT is based on LU centering transmission detection and it improves the resolution of the detection system by using the characteristics of ultrasonic propagation and its mode conversion. It is firstly studied in theory with a numerical model based on finite element method (FEM), and then it is applied in experiments to reconstruct the defect according to the signals detected by LU method. In our experiment, the artificial defects buried in an AM sample with diameter from 0.2 mm to 0.75 mm are successfully characterized by the SAFT imaging of ultrasonic signals. The results prove that the position of the defect in 3D and its size can be successfully obtained by the proposed SAFT.

Design of a single input control signal for fault-tolerant synchronization of fractional order hyperchaotic Lu system

ABSTRACT The authors of this paper used an adaptive-sliding mode controller (A-SMC) to synchronise two fractional-order hyperchaotic (FOHC) Lu systems in the presence of external disturbance and bounded parametric uncertainty with unknown bounds. They employed the Riemann–Liouville fractional order and defined a new fractional-order sliding surface for the FOHC Lu system to determine a proper active control. Additionally, they utilised adaptive laws to estimate uncertainty bounds and unknown disturbance signals. The authors proved the stability of the closed-loop control system using the Lyapunov theory. Simulation results in MATLAB demonstrated the desirable performance of this method in the presence of disturbance and parametric uncertainty.

Oxygen–Ion Conductivity, Dielectric Properties and Spectroscopic Characterization of “Stuffed” Tm2(Ti2−xTmx)O7−x/2 (x = 0, 0.1, 0.18, 0.28, 0.74) Pyrochlores

Tm2(Ti2−xTmx)O7−x/2 (x = 0, 0.1, 0.18, 0.28, 0.74) solid electrolytes have been investigated as potential electrolyte materials for solid oxygen fuel cells (SOFCs), operating in the medium temperature range (600–700 °C). The design of new oxygen-conducting materials is of importance for their possible utilization in the solid oxide fuel cells. The oxygen–ion conductivity of the Tm2(Ti2−xTmx)O7−x/2 (x = 0, 0.1, 0.18, 0.28, 0.74) “stuffed” pyrochlores ceramics was investigated by electrochemical impedance spectroscopy (two-probe AC) in dry and wet air. The synthesis of precursors via co-precipitation and the precipitate decomposition temperature have been shown to be of key importance for obtaining dense and highly conductive ceramics. At ~770 °C, the highest total conductivity, ~3.16 × 10−3 S/cm, is offered by Tm2Ti2O7. The conductivity of the fluorite-like solid solution Tm2(Ti2−xTmx)O7−x/2 (x = 0.74) is an order of magnitude lower. However, for the first time a proton contribution of ~5 × 10−5 S/cm at 600 °C has been found in Tm2(Ti2−xTmx)O7−x/2 (x = 0.74) fluorite. Until now, compositions with proton conductivity were not known for the intermediate and heavy rare earth titanates Ln2(Ti2−xLnx)O7−x/2 (Ln = Ho − Lu) systems. The use of X-ray diffraction (structural analysis with Rietveld refinement), optical spectroscopy and dielectric permittivity data allowed us to follow structural disordering in the solid solution series with increasing thulium oxide content. High and low cooling rates have been shown to have different effects on the properties of the ceramics. Slow cooling initiates’ growth of fluorite nanodomains in a pyrochlore matrix. The fabrication of such nanostructured dense composites is a promising direction in the synthesis of highly conductive solid electrolytes for SOFCs. We assume that high-temperature firing of nanophase precursors helps to obtain lightly doped “stuffed” pyrochlores, which also provide the high oxygen–ion conductivity.

New results on T–S fuzzy sampled-data stabilization for switched chaotic systems with its applications

This study presents a T–S fuzzy-based sampled-data controller for switched chaotic systems. First, we designed the switched-based sampled-data fuzzy controller. Second, a novel time-dependent Lyapunov–Krasovskii functional (LKF) approach with the information of switching signals is proposed, which covers all information of the sampling interval and the time-delay information in the controller, improving the integral inequality, some sufficient conditions are established, which makes the proposed closed-loop system be exponentially stable. Subsequently, the derived conditions are formulated with respect to linear matrix inequalities (LMIs). Meanwhile, the corresponding sampled-data controller gains are designed under the larger sampling interval. Finally, the suggested T–S fuzzy sampled-data controller (TSFSD) is used to demonstrate the usefulness of the approaches in the Lorenz system, Chen system, and Lu system.

Thermodynamic assessment of the Ga–Lu system by the combination of ab-initio calculations and the CALPHAD approach

First-principles calculations within DFT (density functional theory) were employed to calculate the enthalpies of formation of the metal compounds in the Ga–Lu system. The phase diagram and thermodynamic data of this system were critically optimized using the CALPHAD method and Thermo-Calc software. The Ga–Lu phase diagram contains five intermetallic compounds: Ga3Lu, Ga2Lu,Ga5Lu3, GaLu and Ga3Lu5. These phases were stoichiometric except Ga3Lu5 that has a homogeneity range, was modeled by a two-sublattice model with substitution in each sublattice.The Ga–Lu system was evaluated using the substitutional solution model and the associate model to the description of the liquid phase, in which the excess Gibbs free energy (Gex) was formulated with Redlich–Kister polynomial. The values of the enthalpies of formation that we obtained using two models are in good agreement with those calculated in this work using the VASP code and with experimental data from the literature. The optimization procedure allows us to optimize for the first time all invariant equilibria, thermodynamic properties of the liquid phase and intermetallic compounds of the Ga–Lu system.

Image encryption based on fractional chaotic pseudo-random number generator and DNA encryption method

Nonlinear dynamic systems and chaotic systems have been quite exhaustively researched in the domain of cryptography. However, the possibility of using fractional chaotic systems in the cryptosystem design has been much less explored while it bears advantages such as enlarged keyspace and better resistance to attack compared to classical nonlinear systems. This paper, therefore, proposes a novel structure for the pseudo-random number generator based on 3 different fractional chaotic systems, namely fractional Chen system, Lu system, and fractional generalized double-humped logistic map. Then, the outputs of this fractional chaotic pseudo-random number generator are used as a keystream for an image encryption scheme. The confusion layer of the scheme is conducted by a dynamic DNA encoding and decoding method combined with a 2D cat map for the permutation in the DNA bases level. The diffusion layer is performed through the adoption of a 32 bits discrete logistic map. The performance and security analyses have been conducted for the above-designed cryptosystem, proving that the proposed cryptosystem is practical and efficient, and can be successfully implemented in image encryption.

Design of multi-wing chaotic systems with higher largest Lyapunov exponent

A multi-wing chaotic attractor with higher value of the largest Lyapunov exponent is more useful for its practical applications. This paper proposes a new design technique to generate multi-wing chaotic attractors from two-wing chaotic attractors, available in the literature. The Chen and the Lu systems are considered for demonstration. A nonlinear term of the original system is multiplied by a nonlinear function to generate multi-wings attractors. The number of wings is changed by varying the number of equilibrium points, and the equilibrium points are changed by varying the parameters of the newly added nonlinear function. The new multi-wing chaotic systems have a higher value of the largest Lyapunov exponent than their respective original systems. An interesting behavior is observed in the proposed system, i.e., the largest Lyapunov exponent increases with the variation of a system parameter. Further, the largest Lyapunov exponents of the new systems are much higher than some similar available papers.

Molecular blood group screening in Omani blood donors.

Blood group genotyping has been used in different populations. This study aims at evaluating the genotypes of common blood group antigens in the Omani blood donors and to assess the concordance rate with obtained phenotypes. Blood samples from 180 Omani donors were evaluated. Samples were typed by serological methods for the five blood group systems MNS, RH (RHD/RHCE), KEL, FY and JK. Samples were genotyped using RBC-FluoGene vERYfy eXtend kit (inno-train©). Predicted phenotypic variants for 70 red blood cell antigens among the MNS, RH (RHD/RHCE), KEL, FY, JK, DO, LU, YT, DI, VEL, CO and KN blood group systems were assessed. Simultaneous phenotype and genotype results were available in 130 subjects. Concordance rate was >95% in all blood group systems with exception of Fy(b+) (87%). Homozygous GATA-1 mutation leading to erythroid silencing FY*02N.01 (resulting in the Fy(b-)ES phenotype) was detected in 81/112 (72%) of genotyped samples. In addition, discrepant Fyb phenotype/genotype result was obtained in 14/112 samples; 13 of which has a heterozygous GATA-1 mutation and one sample with a wild GATA genotype. D and partial e c.733C>G variants expressing the V+VS+ phenotype were found in 22/121 (18.2%) and 14/120 (11.7%) of the samples, respectively. Di(a-b+), Js(a-b+), Yt(a+b-) and Kn(a+b-) genotype frequencies were 99.4%, 95.8%, 91.9% and 97.7%, respectively. In conclusion, we report a high frequency of FY*02N.01 allele due to homozygous c.-67T>C GATA-1 single-nucleotide variation. This is the first study reporting the detailed distribution of common and rare red cell genotypes in Omani blood donors.

A Novel Chaotic System with Wide Spectrum, its Synchronization, Circuit Design and Application to Secure Communication

Objective: To investigate a novel chaotic system with unique features, its synchronization using nonlinear active control, analog circuit design and application to secure communication. Methods/Analysis: Dynamical tools such as dissipative analysis, instability of equilibrium points, sensitivity to initial conditions, 0-1 test, recurrence plot, Poincare map, Lyapunov exponents, Lyapunov dimension, frequency spectrum and basin of attraction. Synchronization is achieved using modified nonlinear active control technique and analog circuit design, implementation is done in NI Multisim platform. MATLAB and Multisim results are presented to meet the adequate verification of theoretical approach. Findings: A three-dimensional chaotic system with only two nonlinear terms, three parameters and a total of eight terms are proposed. The proposed system has three saddle focus type equilibria. The proposed system is topologically different from Lorenz’s and Rossler’s, Lu’s, Chen’s, and Liu’s families. Such dynamic systems are very few in the literature as per authors best knowledge. The system has basin of chaotic attractors for which first Lyapunov exponent ranges between 2.5 to 3. Frequency spectrum and large positive Lyapunov exponent result comparatively large bandwidth of the proposed systems against some well-known chaotic systems. Chaos, periodic and stable behaviors are obtained by altering the system parameters. Novelty/Application: The proposed three-dimensional chaotic system has significant chaotic behavior and broader spectrum than the six chaotic systems like Lorenz, Rossler, Lu, Chen, BG and Liu systems. Unlike the conventional active control approach, the proposed nonlinear active control does not result decoupled error dynamics. The system has significantly large bandwidth which is helpful in the masking of message signals and enhances the security of transmitted signals during communication. Keywords: Analog circuit design; Chaos; Chaotic system; Chaosbased communication; Chaos synchronization; Nonlinear active control

Hyperbolic uncertainty estimator based fractional order sliding mode control framework for uncertain fractional order chaos stabilization and synchronization

This paper formulates a new fractional order (FO) integral terminal sliding mode control algorithms for the stabilization and synchronization of N-dimensional FO chaotic/hyper-chaotic systems, which are perturbed with unknown uncertainties. In order to render closed loop robustness, a novel efficient double hyperbolic functions based uncertainty estimator is developed for the estimation and mitigation of unknown uncertainties. Moreover, a double hyperbolic reaching law comprising of tangent hyperbolic and inverse sine hyperbolic functions is incorporated in the presented control techniques for the practical convergence of various chaotic system states and tracking errors to infinitesimally close to equilibrium. Examples such as FO Lu, FO Chen and FO Lorenz systems are taken to investigate robustness, finite time convergence, tracking accuracy and closed loop stability properties of the devised methodologies. Last but not least, comparative analysis is also carried out between the proposed and prior control techniques through various time domain performances such as settling time, error indices and measure of control energy.

Exponential synchronization of fractional-order complex chaotic systems and its application

In this article, exponential synchronization between fractional order chaotic systems has been studied by using exponential stability theorem. The stability analysis has been done with help of an existing lemma, which is given for Lyapunov function for fractional order system. The fractional order complex chaotic systems viz., Lorenz and Lu systems are considered to illustrate the exponential synchronization. The numerical simulation results are presented through graphical plots to verify the effectiveness and reliability of exponential synchronization. The application in communication through digital cryptography is also discussed between the sender (transmitter) and receiver using the exponential synchronization. A well secured key system of a message is obtained in a systematic way.

Phase Diagrams of Lead Difluoride Systems with Rare-Earth Fluorides

Phase equilibria in the PbF2–RF3 (R = La–Nd, Sm, Gd–Lu, Y, and Sc) systems were studied by X-ray powder diffraction in samples annealed under a fluorinating atmosphere and then quenched and by differential thermal analysis (DTA) under an inert atmosphere using unlidded thin-walled graphite crucibles. Stability areas were elucidated for Pb1 – xRxF2 + x fluorite solid solutions, for R1 – yPbyF3 – y solid solutions having the tysonite LaF3 structure, and for ordered phases of idealized composition Pb4R3F17 having trigonally distorted cubic unit cells. The topological evolution of the systems in response to the changing rare-earth ionic radius was considered.

Design of a Fractional Pseudo-Chaotic Random Number Generator

In this paper, we design a pseudo-chaotic random number generator using fractional chaotic systems. A non-uniform grid calculation method is proposed and employed to numerically solve the fractional systems by introducing a skew-tent map to vary the step size of the grid. Greater chaoticity in terms of Lyapunov exponent has been achieved by applying the proposed approach to the solution calculation of the fractional chaotic Chen's and Lu's systems. By adopting the piecewise constant argument method, one 1D fractional generalized double-humped logistic system (FGDHL) is discretized. A fractional pseudo-chaotic random number generator (FPCRNG) has been proposed by performing XOR (exclusive-or) operations to the states of the fractional Chen's system, fractional Lu's system, and the FGDHL systems. The security analysis of the generator and the statistical experiment of a stream cipher implementing the proposed FPCRNG prove that the proposed structure is efficient and can be used in the cryptosystem design.

The $$\psi $$-Hilfer fractional calculus of variable order and its applications

In this paper, we present the $$ \psi $$ -Hilfer fractional derivatives of variable order (FDVO) of 3 types I, II and III, versions A and B, as well as their combinations. In addition, we propose approximations and relations between both derivatives, i.e., $$ \psi $$ -Hilfer FDVO and $$ \psi $$ -Caputo FDVO. With regard to the $$ \psi $$ -Hilfer FDVO type II, we discuss the stability of the FVO nonlinear systems 7 solutions by means of one-parameter Mittag-Leffler functions of variable order. Examples 8 involving the FDVO Lu and Chen systems are also presented.

An exponential chaotic oscillator design and its dynamic analysis

After years of development, chaotic circuits have possessed many different mathematic forms and multiple realization methods. However, in most of the existing chaotic systems, the nonlinear units are composed of the product terms. In this paper, in order to obtain a chaotic oscillator with higher nonlinearity and complexity to meet the needs of utilization, we discuss a novel chaotic system whose nonlinear term is realized by an exponential term. The new exponential chaotic oscillator is constructed by adding an exponential term to the classical Lu system. To further investigate the dynamic characteristics of the oscillator, classical theoretical analyses have been performed, such as phase diagrams, equilibrium points, stabilities of the system, Poincare mappings, Lyapunov exponent spectrums, and bifurcation diagrams. Then through the National Institute of Standards and Technology &#x0028 NIST &#x0029 statistical test, it is proved that the chaotic sequence generated by the exponential chaotic oscillator is more random than that produced by the Lu system. In order to further verify the practicability of this chaotic oscillator, by applying the improved modular design method, the system equivalent circuit has been realized and proved by the Multisim simulation. The theoretical analysis and the Multisim simulation results are in good agreement.

Finite time synchronization of fractional chaotic systems with several slaves in an optimal manner

Optimal synchronization of chaotic fractional differential equations with one master and several slaves in finite time is the main aim of this paper. To achieve this goal, we convert the finite time synchronization problem to a fractional optimal control problem; then by solving it, we achieve the active control. In this way, we use Bernstein polynomials and prove that the corresponding minimization problem is a quadratic convex problem. Some examples using the famous Lorenz, Chen, Lu, and Liu systems are given to show the efficiency of the method.

Finite-time synchronization of hyperchaotic systems based on feedback passivation

Abstract This paper proposes a scheme to realize finite-time synchronization of hyperchaotic systems using a feedback passivation technique. Although the technique is widely known, its utilization for finite-time control problems is still considered to be new since finite-time passivity has been just recently introduced. The proposed scheme consists of few design steps. First, a feedback is designed such that it yields finite-time stability for the zero-dynamics of the synchronization errors. Then, the synchronization errors is transformed into a finite-time passive system by an additional feedback. Consequently, the finite-time convergence of the synchronization errors is obtained. The hyperchaotic Lu system and a 5D Lorenz-like system are used as examples to demonstrate the effectiveness of the scheme.

Stability Analysis, Control of Simple Chaotic System and its Hybrid Projective Synchronization with Fractional Lu System

In this article, the stability analysis and chaos control of Simple chaotic system have been discussed. A new lemma based on Caputo derivative is used during the stability analysis of the fractional order Simple chaotic system through Lyapunov stability theory. During hybrid projective synchronization the Simple chaotic system is considered as drive system and Lu chaotic system is taken as response system. Nonlinear control method has been used to analyse the hybrid projective synchronization of fractional systems. For numerical simulations Adams-Bashforth-Moulton method has been used and results obtained are presented graphically.

Modeling and Inverse Complex Generalized Synchronization and Parameter Identification of Non-Identical Nonlinear Complex Systems Using Adaptive Integral Sliding Mode Control

This paper presents the Inverse Complex Generalized Synchronization (ICGS) of non-identical nonlinear complex systems with unknown parameters. Using the philosophy of adaptive integral sliding mode control, an adaptive controller and laws regarding parametric upgradation are designed to realize ICGS and parameter identification of two non-identical chaotic complex systems with respect to a given complex map vector. To employ the control, the error system is transformed into a unique structure containing a nominal part and some unknown terms, which are computed adaptively. Then, the error system is stabilized by using integral sliding mode control. The stabilizing controller for the error system is constructed, which consists of the fractional-order control plus some compensator control. To avoid the chattering phenomenon, smooth continuous compensator control is incorporated instead of traditional discontinuous control. The compensator controller and the adapted law are derived in such a way that the time derivative of a Lyapunov function becomes strictly negative. This scheme is applied to synchronize a Memristor-Based Hyperchaotic Complex (MBHC) Lu system and a Memristor-Based Chaotic Complex (MBCC) Lorenz system, a chaotic complex Chen system and a memristor-based chaotic complex Lorenz system with entirely unknown parameters. The effectiveness and feasibility of the proposed scheme is validated through computer simulation using MATLAB software package.