Output-feedback Dynamic Surface Control for a Class of Nonlinear Non-minimum Phase Systems

In this paper, an output-feedback tracking controller is proposed for a class of nonlinear non-minimum phase systems.To keep the unstable internal dynamics bounded, the method of output redefinition is applied to let the stability of the internal dynamics depend on that of redefined output, thus we only need to consider the new external dynamics rather than internal dynamics in the process of designing control law. To overcome the explosion of complexity problem in traditional backstepping design, the dynamic surface control(DSC) method is firstly used to deal with the problem of tracking control for the nonlinear non-minimum phase systems. The proposed outputfeedback DSC controller not only forces the system output to asymptotically track the desired trajectory, but also drives the unstable internal dynamics to follow its corresponding bounded and causal ideal internal dynamics, which is solved via stable system center method. Simulation results illustrate the validity of the proposed output-feedback DSC controller.

Measurement and Correlation of Equilibrium Data for Aqueous Two-phase System Ethanol+Water+ K_2HPO_4

The isothermal solubility data of aqueous two-phase system ethanol+water+K 2HPO 4 were determined with the turbidity titration method at 303.2 K. The binodal curves were described by using the Mistry equation very well. An experimental procedure for measuring the liquid-liquid equilibrium data of the aqueous two-phase system was proposed, in which the concentrations of the coexisting phases were determined with the corresponding densities of the solution. The tie lines were satisfactorily described by using the Othmer-Tobias and Bancroft equations.

Ionic Liquid-salt Aqueous Two-phase System, a Novel System for theExtraction of Abused Drugs

A 1-butyl-3-methylimidazolium chloride-salt aqueous two-phase system was studied on extraction of abused drugs. The effects of sorts of salts, temperature, concentration of salt and drugs on system were investigated systematically. A satisfactory extraction efficiency of 93% was obtained for papaverine while that of morphine was 65%. The extraction mechanism was primarily discussed.

Partition coefficient prediction of Baker's yeast invertase in aqueous two phase systems using hybrid group method data handling neural network

A hybrid GMDH neural network model has been developed in order to predict the partition coefficients of invertase from Baker's yeast. ATPS experiments were carried out changing the molar average mass of PEG(1500–6000 Da), p H(4.0–7.0), percentage of PEG(10.0–20.0 w/w), percentage of MgSO_4(8.0–16.0 w/w), percentage of the cell homogenate(10.0–20.0 w/w) and the percentage of MnSO_4(0–5.0 w/w) added as cosolute. The network evaluation was carried out comparing the partition coefficients obtained from the hybrid GMDH neural network with the experimental data using different statistical metrics. The hybrid GMDH neural network model showed better fitting(AARD = 32.752%) as well as good generalization capacity of the partition coefficients of the ATPS than the original GMDH network approach and a BPANN model. Therefore hybrid GMDH neural network model appears as a powerful tool for predicting partition coefficients during downstream processing of biomolecules.

The Solid-liquid Transformation of Low-grade Solid Potash Deposit in Dalangtan Basin and the Simplification of the Liquid Phase System

We studied the solid-liquid transformation of low-grade solid potash deposit in Dalangtan Basin and simplified the liquid phase system.We did experiments to optimize conditions of the solid-liquid transformation.The Suitable

Copper(Ⅰ)-catalyzed Synthesis of Aryl, Heteroaryl and Vinyl Sulfides in Aqueous Two-phase System

A fast and convenient C―S bond formation reaction was achieved catalyzed by CuI/L-proline in aqueous two-phase system providing a simple method for synthesis of aryl sulfides in good yields in short time.

Stability of Motion ＂In the Large＂ of Some Class of Phase Systems

This article focuses on the study of stability of motion of the phase systems described by differential equations whose right-hand sides are periodic in the angular coordinate. The article deals with the mathematical model which has been investigated for stability ＂in the large＂ using the second Lyapunov method. Based on the theoretical results obtained in the work,the computational experiments on concrete examples of electric power systems, which showedthe sufficient efficacy of the proposed method for the studied phase system, were conducted.

Novel Vesicular Aqueous Two-Phase Systems

The interesting phenopmena of two aqueous phases coexisting in dilute aqueous solutions of sodium undecenoate-dodecyltrimethylammo brodride ndxture and sodium laurate-dodecyltrimethylammonium brondde mixture were investigated. Vesicles existing in both phases were shown by TEM images. The vesicles are dispersed in lower phase and flocculated in upper phase. Multilamellar structure of vesicles was found in the upper phase of sodium laurate-dodecyltrimethylammonium bromide system.

Correlation between Carrier Concentration and Superconductivity in the 123-phase System

Besides the structure and oxygen content,the resistance-temperature relationship,Hall carrier concentration(nH)and midpoint temperature of superconducting transition(T_(c))were measured for more than six 123-phase systems with elemental substitution.No correlation is found between the oxygen content and T_(c),nor is between the orthorhombic structure and T_(c).Instead,an unmonotonic relationship is jound between nH and T_(c).The optimum nH for the highest T_(c) is about 3.8 x1021cm-3.All this draws a conclusion that nH is a parameter to describe the high T_(c) superconductivity.

Enhancement of Shikonin Production in Cell Suspension Cultures of Arnebia Euchroma Employing Two-Liquid-Phase Systems

1 INTRODUCTIONThe production of secondary metabolites using plant cells has been the subject of much inter-est in recent years.Despite that tremendous research efforts had been made in this topic,notmany products have reached the commercial stage.It is generally acknowledged that the mainproblem in this field is the lack of basic knowledge of the biosynthetic routes,and the mechanisms found to bring about the production of such secondary metabolites.There are,however,some techniques that have beneficial effects on the production and ex-

Effects of Hydrophobicity of Ethylene Oxide-Propylene Oxide Copolymers on Phase Diagrams of Aqueous Two-Phase Systems and Partition Behaviors of Cephalexin and 7-Aminodeacetoxicephalos-poranic Acid

A series of ethylene oxide (EO)-propylene oxide (PO) randomco-polymers (EOPO) were used to form aqueous two-phase systems (ATPS)with ammonium sulfate. Effects of EOPO's properties on the phaseseparation behaviors and on the partition of cephalexin and7-aminodesacetoxicephalosporanic acid (7-ADCA) in ATPS wereinvestigated. Both the molar mass and molar ratio of EO to PO of EOPOcould greatly influence partition behaviors of cephalexin and 7-ADCAas well as the binodal curve of ATPS.

Micromixing of a Two Phase System in a Stirred Tank with Multiple Impellers

The competitive iodide/iodate reaction scheme was used to ascertain the micromixing in the stirred solid-liquid systems. Two different glass beads from 450 to 1250 μm were tested. The effect of solid particles on reaction selectivity with multiple impellers at different feed points has been investigated. It was confirmed that glass beads as a second phase were suitable for the study. The segregation index has changed significantly only for the medium-sized particles at relatively high solid holdups. The cloud formation was clearly observed for the medium-sized particles at a concentration of 12.12 wt. %. When feeding into the clear liquid above the cloud, the value of the segregation index increased significantly. However, in the presence of particles of 1-1.25 mm, the influence on the selectivity was negligible when the agitation speed was increased.

Separation/Analysis Rhodamine B by Anion Surfactant/Ionic Liquid Aqueous Two-Phase Systems Coupled with Ultraviolet Spectrometry

A novel method for the separation/analysis rhodamine B has been described. The ionic liquid (1-tetradecyl-3-methylimidazolium bromide)/anion surfactant (sodium dodecyl sulfate)/NaCl two-phase systems (ATPSs) is presented as a simple, rapid and effective sample pretreatment technique coupled with ultraviolet spectrometry for analysis rhodamine B in soft drink. The effects of parameters on the ATPSs extraction of rhodamine B such as amount of surfactant, ionic liquid and salt, pH, temperature, stabilization and centrifugal time have been studied in details. Under the optimized conditions, the linear range of calibration curve for rhodamine B was 0.05 - 7.0 μg·mL-1 and the detection limit was 3.2 ng·mL-1. The phase equilibrium and the mechanism of phase separation for ATPSs have been discussed. This method has been applied to the determination of rhodamine B in soft drink.

The First Five Years of a Phase Theory for Complex Systems and Networks

In this paper,we review the development of a phase theory for systems and networks in its first five years,represented by a trilogy:Matrix phases and their properties;The MIMO LTI system phase response,its physical interpretations,the small phase theorem,and the sectored real lemma;The synchronization of a multi-agent network using phase alignment.Towards the end,we also summarize a list of ongoing research on the phase theory and speculate what will happen in the next five years.

Phase equilibria relations in the V_(2)O_(5)-rich part of the Fe_(2)O_(3-)TiO_(2)-V_(2)O_(5) system at 1200℃ related to converter vanadium-bearing slag

The efficient recycling of vanadium from converter vanadium-bearing slag is highly significant for sustainable development and circular economy.The key to developing novel processes and improving traditional routes lies in the thermodynamic data.In this study,the equilibrium phase relations for the Fe_(2)O_(3)-TiO_(2)-V_(2)O_(5)system at 1200℃in air were investigated using a high-temperature equilibrium-quenching technique,followed by analysis using scanning electron microscopy-energy dispersive X-ray spectrometer and X-ray photoelectron spectroscopy.One liquid-phase region,two two-phase regions(liquid-rutile and liquid-ferropseudobrookite),and one three-phase region(liquid-rutile-ferropseudobrookite)were determined.The variation in the TiO_(2)and V_(2)O_(5)contents with the Fe_(2)O_(3)content was examined for rutile and ferropseudobrookite solid solutions.However,on further comparison with the predictions of FactSage 8.1,significant discrepancies were identified,highlighting that greater attention must be paid to updating the current thermodynamic database related to vanadium-bearing slag systems.

Enhanced entropy generation and heat transfer characteristics of magnetic nano-encapsulated phase change materials in latent heat thermal energy storage systems

The objective of the current study is to investigate the importance of entropy generation and thermal radiation on the patterns of velocity,isentropic lines,and temperature contours within a thermal energy storage device filled with magnetic nanoencapsulated phase change materials(NEPCMs).The versatile finite element method(FEM)is implemented to numerically solve the governing equations.The effects of various parameters,including the viscosity parameter,ranging from 1 to 3,the thermal conductivity parameter,ranging from 1 to 3,the Rayleigh parameter,ranging from 102 to 3×10^(2),the radiation number,ranging from 0.1 to 0.5,the fusion temperature,ranging from 1.0 to 1.2,the volume fraction of NEPCMs,ranging from 2%to 6%,the Stefan number,ranging from 1 to 5,the magnetic number,ranging from 0.1 to 0.5,and the irreversibility parameter,ranging from 0.1 to 0.5,are examined in detail on the temperature contours,isentropic lines,heat capacity ratio,and velocity fields.Furthermore,the heat transfer rates at both the cold and hot walls are analyzed,and the findings are presented graphically.The results indicate that the time taken by the NEPCMs to transition from solid to liquid is prolonged inside the chamber region as the fusion temperatureθf increases.Additionally,the contours of the heat capacity ratio Cr decrease with the increase in the Stefan number Ste.

Robust adaptive leaderless consensus of unknown non-minimum phase linear multi-agent systems subject to disturbances and/or unmodeled dynamics

This article investigates the problem of robust adaptive leaderless consensus for heterogeneous uncertain nonminimumphase linear multi-agent systems over directed communication graphs. Each agent is assumed tobe of unknown nominal dynamics and also subject to external disturbances and/or unmodeled dynamics. Anovel distributed robust adaptive control strategy is proposed. It is shown that the robust adaptive leaderlessconsensus problem is solved with the proposed control strategy under some sufficient conditions. Two examplesare provided to demonstrate the efficacy of the proposed control strategy.

Design of a Three-Phase Grid Connector System Using Power Transfer from Park’s Transformation

Instabilities in grid-connected inverters can arise from a number of sources, including mismatched parameters, grid impedance, faults, and feedback delays. Park’s transformation provides accurate control over reactive and active (real) power. This enhances the overall efficiency of the system by enabling operators to control reactive power compensation and optimize energy flow. In dynamic settings, this guarantees greater system stability and faster response times. The current paper aims to improve the grid system by utilizing the dq0 controller. The current work focuses on the analysis based on simulations and theory, where the state space equation serves as the basis for dq-axis current decoupling. A MATLAB platform was used to simulate the complete system. TDH values of 2.45%, or less than 5%, in the given results are acceptable. The suggested controller was hence appropriate for grid system applications.

基于CTA颅内动脉瘤形态联合PHASES评分对破裂出血预测研究

目的:分析头颈部计算机断层扫描血管成像(CTA)联合PHASES评分对颅内动脉瘤(IA)破裂出血的预测价值。方法:回顾性分析2021年10月—2023年9月东莞市长安医院诊治的IA患者临床资料,根据IA破裂出血与否分为IA破裂组(n=46)和IA未破裂组(n=44),收集两组临床资料,对比两组患者CTA影像瘤体特征参数和PHASES评分结果。采用受试者工作特征(ROC)曲线分析两者联合预测动脉瘤破裂的效能。结果:IA破裂组高血压、糖尿病发生率及PHASES评分均高于IA未破裂组,差异有统计学意义(P <0.05)。两组病灶位置以颈内动脉(ICA)和大脑中动脉(MCA)为主,但IA破裂组病灶位置在MCA的占比为41.30%,高于IA未破裂组的20.45%,瘤体>7 mm的最多(瘤体7~9.9 mm占65.22%),瘤体形态不规则占58.7%,未破裂组病灶位置在ICA最多(68.18%),瘤体<7 mm的居多(75.00%),瘤体形态规则囊状动脉瘤占93.18%,差异有统计学意义(P <0.05)。CTA瘤体特征参数比较,IA破裂组患者瘤颈宽度、瘤体高度、瘤体长度、动脉瘤最大直径、入射夹角、动脉瘤体颈比等参数均高于IA未破裂组,差异有统计学意义(P <0.05)。CTA瘤体特征参数+PHASES评分联合预测曲线下面积为0.916,高于CTA瘤体特征参数(0.901)和PHASES评分(0.731)。结论:CTA瘤体特征参数+PHASES评分联合预测IA患者破裂出血效能最佳。