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In this contribution, a new approach to design interval observer for continuous-time linear systems is introduced. First, a more general structure than the classical Luenberger observer is proposed and extended to the interval case based on an explicit set integration method. Then, to obtain tight state enclosures, the computation of the design matrices involved in this new structure is formulated as a nonlinear constrained optimisation problem. In addition, using the symmetric property of interval vectors, a less complex form of the proposed interval observer is presented. On the other hand, compared to the conventional interval observers, no preserving order property on the dynamics of the estimation error is required to apply the introduced method. A numerical case study example is considered to illustrate the effectiveness of the proposed method and to compare its performance to that of a former method. [ABSTRACT FROM AUTHOR]

Under the uncertainty of conservation tillage on output, technology demonstration, as an information disclosure mechanism, is very worthy of attention for its effects on rural households' conservation tillage adoption. This study constructs a three-stage technology adoption model to discuss the theoretical relationship between technology demonstration and rural households' conservation tillage adoption decision, and then empirical analyzed it using a sampling rural household data from six provinces in the main grain-producing areas of China. The results show that: First, the cognition of conservation tillage is the pre-determined stage for the adoption and its intensity. Second, technology demonstration has significant positive effect on rural households' cognition of conservation tillage, but it strongly negative related to the adoption and adoption intensity. Third, extending the technology demonstration time cannot change the rural households' adoption decision. Fourth, the technological demonstration has similar effects on the conservation tillage adoption of small-scale and large-scale farmers. Fifth, increasing land size helps rural households to adopt conservation tillage, while land fragmentation hinders their adoption. [ABSTRACT FROM AUTHOR]

Terahertz modulators possess fascinating physical properties, which is widely used in medical imaging, signal communication and security detection. However, the highprecision control and frequency shift of terahertz wave is still limited in the application field of terahertz devices. Here we propose a metasurface with a cube structure, and the control and frequency shift of terahertz wave are realized by the increase of relative dielectric constant and thickness of the cube structure. The results show that the terahertz frequency response peak of metasurface structure is red shifted, when the dielectric constant of cube structure is increased from 6 to 12.94. Meanwhile, the thickness of the cube structure has an effect on the red shift of the reflection frequency of the terahertz superstructure. When the thickness of the surface material is increased from 1 μm to 3 μm. the reflectance coefficient peak of super surface structure is blue shifted from 11.2 THz to 11.6 THz. This method may be used in advanced applications that need to control electromagnetic waves, such as perfect absorber and smart sensor components. [ABSTRACT FROM AUTHOR]

This paper is concerned with prescribed-time functional unknown input observer (PTFUIO) design for linear descriptor systems. First, by constructing two identical asymptotic convergence functional observers, a new PTFUIO is developed which can achieve an exact estimation within an arbitrarily prescribed time, where both the estimation accuracy and the convergence time pre-definition are independent of the initial conditions of the original system. Also, the necessary and sufficient conditions for the existence of such the PTFUIO are given in terms of the original system matrices which are easy to examine. Finally, numerical simulations are given to illustrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

An interval estimation method based on the reduced-order observer and peak-to-peak analysis is proposed for continuous-time linear time-invariant systems with disturbance and measurement noise. The proposed method consists of two steps. First, a reduced-order observer with L ∞ performance is designed to obtain point estimation. Second, interval estimation is achieved by integrating the obtained point estimation and the error interval estimation by peak-to-peak analysis. Steady-state gain optimisation in terms of linear matrix inequalities is used in both steps to improve the estimation accuracy of the proposed method. The superiority of the method over the reduced-order interval observer is illustrated through numerical simulations. [ABSTRACT FROM AUTHOR]

Based on Molecular Dynamics (MD), construct a crystallization model of Ni-Fe alloy and an amorphous model by simulating atomic deposition, stretch the models with the X axis and got the stress-strain curve. It is clearly observed that the maximum strain of the crystallization model is 0.25, and the maximum bearing stress is 450 MPa, it is fits perfectly with the objective reality data; the maximum strain of the amorphous model is about 0.3, and the maximum stress is 480 MPa, its ductility significantly higher than the crystallization model. In addition, by changing the temperature, it can be found easily that the maximum stress of the model is decreasing and the maximum strain is increasing. This indicates that under the influence of temperature, the hardness of the Ni-Fe alloy will decrease by 14%, while the ductility and toughness will increase by 7.7% with a temperature change of 150 K. [ABSTRACT FROM AUTHOR]

The effective parameters of artificial medium are designed to realize the perfect absorption of terahertz wave (THz), which has become one of the significant issues related to metamaterial. However, the planar structure of metamaterial has many limitations. Here, we establish a three-dimensional structure of split ring resonators (SRRs) to realize the vertically coupling SRRs and study its absorption characteristics. The results show that the absorption characteristics of three-dimensional split ring resonators have achieved 99.9% at 1.79 THz. Furthermore, by changing direction of the splits of two rings, we can get broadband absorption of more than 99% in the frequency range of 0.6 THz, which provides a design scheme for three-dimensional metamaterials and potential devices. [ABSTRACT FROM AUTHOR]

Lead–zinc tailings are generated during the mining process which is considered as hazardous solid waste due to its high heavy metal content and leachability in the natural state. At present, the most effective technology for disposing heavy metals in solid wastes is the solidification/stabilization (S/S) technique. In terms of S/S technology, chemical stabilization is one of the most potential and practical method. This paper aims to investigate the S/S property of four typical chemical agents (Na2S, NaH2PO4, TMT and Na2EDTA) on the heavy metals in lead–zinc tailings. The results reveal that the heavy metals lead and zinc in tailings are stabilized more effectively by using chelating agents TMT than by using inorganic chemical agents Na2S and NaH2PO4. When the dosage of TMT reaches 4%, the leaching concentration of lead and zinc is 0.18 and 14.60 mg/L according to toxicity characteristic leaching procedure (TCLP), and the stabilization efficiency of lead and zinc is 99.31% and 80.92%, respectively, while the leaching concentration of lead and zinc just drops to 0.41 and 16.00 mg/L with addition of 10% NaH2PO4. Furthermore, the leaching concentration of heavy metal lead in tailings treated by 4% Na2EDTA increases to 53.44 mg/L which far exceeds the standard of pollution control. Therefore, considering stabilization efficiency and dosage, TMT is the preferred agent for solidifying heavy metals in lead–zinc tailings. [ABSTRACT FROM AUTHOR]

The present work developed a new Fe-based superalloy of Fe–10.9Cr–13.9Ni–6.4Al–2.2Mo–0.5W–0.04Zr–0.005B (weight percent, wt. %) with cuboidal B2 nanoparticles coherently precipitated into the body-centred-cubic (BCC) matrix. This alloy possesses excellent microstructural stability at 973 K with a slow particle coarsening rate and the B2 nanoprecipitates still keep cuboidal after 1000 h-aging, which is ascribed to the moderate lattice misfit (ϵ = 0.24–0.67%) between BCC and B2 phases. Also, the current alloy exhibits a prominent mechanical property with a high yield strength of σYS = 238–258 MPa at 973 K. A Fe-based superalloy with cuboidal B2 nanoparticles coherently precipitated into BCC matrix exhibits high microstructural stability and prominent mechanical property at 973 K. [ABSTRACT FROM AUTHOR]

This paper investigates the problem of adaptive output-feedback neural tracking control for a class of uncertain switched multiple-input multiple-output (MIMO) nonstrict-feedback nonlinear systems with time delays. It should be emphasised that the design for the considered system is quite difficult due to its unknown factors caused by the unknown system coefficients and the unknown functions. In our proposed design procedure, neural networks (NNs) are introduced to identify the unknown nonlinear functions and a valid hypothesis is used to deal with the unknown system coefficients. Then, the developed switched filter can be utilised to estimate the unmeasured system states. On the basis of the backstepping technique and the common Lyapunov function (CLF) approach, an adaptive neural controller is constructed for each subsystem. It is proved that all signals existing in the switched closed-loop system are ultimately bounded under arbitrary switching and each system output can track the corresponding target trajectory within a small bounded error. Finally, simulation results are presented to illustrate the efficiency of the proposed control method. [ABSTRACT FROM AUTHOR]

The phase transformation mechanism and transformation path of Cu-Ni alloys is very important to study for their applications in excellent electrical properties and chemical catalysis. In this paper, the effect of compressive strain on the transformation path and mechanism of Cu1Ni3 alloy is studied by molecular dynamics simulations. The simulation results reveal that the transformation path of alloys is from Fcc-Bcc-Hcp phase to other phase (amorphous state). The simulations not only revealed the processes of atomic displacements and pair correlation function during the transformation, but also elucidated the underlying mechanism of the transformation at the atomic level. The mechanism of phase transformation could be the lattice reconstruction caused by lattice sliding and stretching. The simulation results provide a clear landscape on the transformation mechanism, facilitating our comprehensive understanding on the phase transition in the Cu-Ni system. [ABSTRACT FROM AUTHOR]

This paper studies the problem of sensor fault interval estimation for discrete-time linear system with unknown but bounded disturbances and noises. A descriptor system which is equivalent to the original system is constructed by considering the fault as an auxiliary state vector. Based on the augmented descriptor system, a zonotopic Kalman filter is designed to obtain the interval estimation of sensor fault. To improve estimation accuracy, we further propose a Frobenius norm minimisation method to design the gain matrix of zonotopic Kalman filter. Finally, numerical simulations of a quadruple-tank system are given to illustrate the effectiveness and superiority of the proposed approach. [ABSTRACT FROM AUTHOR]

In this paper, distributed consensus for a group of high-order discrete multi-agent systems with time-varying delay in the transmission channel is analysed. Suppose that the system is critically unstable and the delay retards the neighbours' state information, some sufficient conditions are built by designing protocol without the delay information in the control gains. Particularly, it is revealed that the constraint of delay on consensus is relaxed thoroughly if the dimension of the system and the parameters of the undirected topology satisfy the developed conditions. Finally, the proposed approaches are supported through two numerical examples. [ABSTRACT FROM AUTHOR]

This paper proposes an interval estimation method for discrete-time linear systems by designing robust reduced-order observer with reachability analysis. First, the discrete-time linear system is transformed into a reduced-order system via a special equivalent transformation, which depends on the orthogonal procedure on the output matrix. Then, a kind of robust reduced-order observer is developed such that the states of the original discrete-time system can be indirectly estimated, where the H ∞ technique is used to attenuate the effects of disturbances. Based on the estimated states provided by the reduced-order observer, the interval estimation can be obtained by reachability analysis. A simulation example is given to illustrate that the proposed method of interval estimation has better performance than the full-order observer-based interval estimation. [ABSTRACT FROM AUTHOR]

This paper studies reachable set estimation for bilinear discrete-time systems with time-varying delays considering state feedback and unknown-but-bounded disturbance. A novel reachable set estimation method based on the zonotopic technique is proposed for the considered systems under non-zero initial conditions. A series of zonotopes can be obtained in the derived theorem for bounding real-time states of the considered systems. The effectiveness of the proposed method is illustrated by a numerical example. [ABSTRACT FROM AUTHOR]

Based on density functional theory, this paper has investigated the stability and electronic structure of Ni–Fe alloy within three different space groups using the first-principles method, and calculated the binding energy, differential charge density and electronic density of states of the optimized space groups. The results show that the order of the three space groups' stability is Pm-3m, I/4mmm and Fm-3m, respectively. Moreover, we find that the bonding electrons are mainly distribute in the range of –5–2 eV, which is mainly contributed by the valence electrons of Fe-3d and Ni-3d. Meanwhile, the s-p electrons show obvious non-localization. This phenomenon indicates that the lost electrons of iron atoms are transfer to nickel atoms, forming metal bonds. [ABSTRACT FROM AUTHOR]

Magnetoelectric composites have attracted much attention due to their strong magnetoelectric coupling effect. In this paper, PbTiO3-NiFe2O4 (PTO/NFO) composite ceramics were prepared by sol-gel method. Effect of sintering temperatures on the structure, dielectric properties and multiferroic properties were studied. XRD results show that PTO/NFO ceramics have been successfully prepared. When the sintering temperature is 1050 °C, the secondary phase PbO2 exists in the ceramics. SEM results show that there were two kinds of grains with different sizes. EDS analysis suggested that the large particles are NFO and the small particles are PTO. The sintering temperature has a great influence on the dielectric and ferroelectric properties of the prepared ceramics. When the sintering temperature is 950 °C, the ceramics show the maximum dielectric constant at low frequency. When the sintering temperature is 1150 °C, the maximum residual polarization is 1.236 μC/cm2. The conductive mechanism of ceramics is dominated by Space Charge – Limited Conduction. The remanent magnetization and coercive field decrease with increasing the sintering temperature. The magnetoelectric coupling coefficient shows that ceramics have strong magnetoelectric coupling performance (5.7 V/cm·Oe). [ABSTRACT FROM AUTHOR]

The main goal of this paper is to present a methodology to design interval observers for discrete-time linear switched systems affected by bounded, but unknown disturbances. Two design techniques are presented. The first one requires that the observation error dynamics are nonnegative while the second one relaxes this restrictive requirement by a change of coordinates. Furthermore, ideas of using H ∞ formalism to compute optimal gains are proposed. Finally, illustrative examples highlight the performance of our methodology. [ABSTRACT FROM AUTHOR]

This paper takes the map load as the evaluation indicator for multi-scale representations of ocean flow fields using Euler method. First, the map load of the ocean flow fields is calculated and the suitable map load interval is analysed in order to obtain the key scale for the multi-scale representation of ocean flow fields. Then, the load is limited by appropriate load intervals to fit the relationship between map load and scale. Finally, a mathematical model for multilevel comprehensive evaluation in fuzzy mathematics is established, and the usability of the resulting ocean flow field map is evaluated using questionnaires. [ABSTRACT FROM AUTHOR]

This paper investigates actuator fault detection and isolation for discrete-time linear descriptor systems. We propose a novel fault detection and isolation scheme based on a bank of H − / L ∞ fault detection observers (FDOs). Under the assumption that the disturbances are unknown but bounded, L ∞ analysis is used to attenuate the effects of disturbances. Meanwhile, the FDO is designed to be sensitive to the fault via considering the H − performance index in finite frequency domain. The design conditions of the proposed FDO are converted into solving a set of linear matrix inequalities. Furthermore, the residual evaluation based on a set-membership approach is proposed to reduce conservatism. Simulation results are provided to demonstrate the performance of the proposed method. [ABSTRACT FROM AUTHOR]

Ba0.7Sr0.3TiO3 ceramics has been synthesized by solid state reaction method. The effects of sintering time on microstructure and electric properties of Ba0.7Sr0.3TiO3 ceramics have been investigated. XRD patterns show that all ceramic samples are single tetragonal phase. The grain size increases with sintering time. Ba0.7Sr0.3TiO3 ceramics show obvious relaxor behavior because of its broadening dielectric peaks and frequency dispersion phenomenon. As sintering time increases, the Curie temperature does not change significantly and the diffuseness of the phase transition of Ba0.7Sr0.3TiO3 ceramics slightly enhances. Moreover, the remnant polarization and coercive field have no obvious changes with the increasing of sintering time. [ABSTRACT FROM AUTHOR]

The crystallization kinetics of Ni-Mn alloy thin films is investigated by molecular dynamic simulation. The results show all curves have a single exothermic peak representing crystallization, and the isothermal peaks are significantly shifted to higher temperatures with increasing heating rate. When heating rate is 5 × 1010 K/s, the crystallization temperatures is found at 715 K. Moreover, we find the crystallization behavior is a two-dimensional grown. Meanwhile, the Radial Distribution Function curves show crystallizing degree at different temperatures and the temperature is 600 K has a crystallization volume fraction is 28%. This work reveals the mechanism of the nucleation and growth in crystallization process. [ABSTRACT FROM AUTHOR]

This paper considers robust fault estimation in the finite frequency domain for linear continuous-time descriptor systems. Based on state augmentation, we propose a fault estimation observer with a non-singular structure. To attenuate the effect of unknown disturbance and fault variation on fault estimation, a fault estimation observer is designed in the finite frequency domain using H∞ optimisation technique. With the design conditions formulated as a set of linear matrix inequalities, the presented fault estimation observer can be efficiently designed. The applicability of the proposed method is verified by numerical simulations of a multi-machine infinite bus system. [ABSTRACT FROM AUTHOR]

To investigate the water mobility during a drying process, noodles were prepared with different gluten contents (10.0%, 12.5%, 15.0%, 17.5%, 20.0%, 22.5%, or 25.0%) and moisture contents (30%, 32%, or 34%), and dried on a food moisture analysis technology platform. Three types of water were deduced from relaxation signals measured by low-field nuclear magnetic resonance (LF-NMR) spectroscopy. Peak time T22 increased with gluten and moisture content but decreased with drying time from 4–6 to 1.0–1.7 ms after 1.5 h. Gluten content mainly affected the drying rate (DR) in the middle drying period, whereas initial moisture content had an influence in the middle drying period and final drying period. [ABSTRACT FROM AUTHOR]

Objective: Direct-acting antiviral agents (DAAs) have been approved for treating hepatitis C virus (HCV) infection in China. However, they are substantially more expensive. The current analysis will investigate the cost-effectiveness of novel regimens compared with pegylated interferon and ribavirin (PR) therapies for informing Chinese decision-makers.Methods: A Markov model was developed to measure economic and health outcomes of novel regimens for genotype 1b, 2, 3, and 6 HCV infections compared with PR treatment. Clinical, cost, and utility inputs were gathered from published sources. Discounted quality-adjusted life-years (QALYs), costs, and incremental cost-effectiveness ratios (ICERs) are shown. The uncertainty was facilitated by one-way and probabilistic sensitivity analyses.Results: For genotype 1b HCV infection, the combination of paritaprevir, ritonavir, ombitasvir and dasabuvir was cost-saving compared with four competing alternatives. The ICERs of sofosbuvir plus ribavirin for genotypes 2 and 3 were lower than the threshold ($18,234/QALY). Among available strategies for patients with genotype 6, sofosbuvir in combination with ribavirin was the cost-saving alternative compared with PR. The results were robust to sensitivity analyses.Conclusions: For both genotype 1b and 6 HCV infections in the context of Chinese patients, there were combinations of DAAs that were cost-saving compared with the usual PR treatment, and cost-effective for genotypes 2 and 3. [ABSTRACT FROM AUTHOR]

This paper studies fault detection problem in the finite-frequency domain for linear systems with parameter uncertainties. We design an fault detection observer to generate residual that is robust against disturbance and sensitive to a fault. In the design, we use the finite-frequency performance index to measure fault sensitivity and introduce performance index to measure the effect of disturbance on residual. The obtained fault detection observer exhibits a peak-to-peak disturbance attenuation performance, which provides a time-varying threshold for residual evaluation. Therefore the proposed design method integrates residual generation and threshold calculation together. To facilitate the observer design process, sufficient conditions of the proposed fault detection observer are formulated as a set of linear matrix inequalities. Numerical simulations are given to verify the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

This paper considers zonotopic fault detection observer design in the finite-frequency domain for discrete-time Takagi-Sugeno fuzzy systems with unknown but bounded disturbances and measurement noise. We present a novel fault detection observer structure, which is more general than the commonly used Luenberger form. To make the generated residual sensitive to faults and robust against disturbances, we develop a finite-frequency fault detection observer based on generalised Kalman-Yakubovich-Popov lemma and P-radius criterion. The design conditions are expressed in terms of linear matrix inequalities. The major merit of the proposed method is that residual evaluation can be easily implemented via zonotopic approach. Numerical examples are conducted to demonstrate the proposed method. [ABSTRACT FROM AUTHOR]

This paper deals with simultaneous fault estimation and control for a class of nonlinear systems with parameter uncertainty, which is described by Takagi–Sugeno (T–S) fuzzy model with parameter uncertainties and unknown disturbance. In this paper, a fuzzy reference model is used to generate error dynamic for tracking control. By considering actuator fault as an auxiliary state vector, we construct an augmented error system and propose a fault estimator/controller to achieve simultaneous fault estimation and fault-tolerant tracking control.H∞approach is used in the design of estimator/controller to attenuate the effect of the unknown disturbance and parameter uncertainties. The design conditions are formulated into a set of linear matrix inequalities (LMIs), which can be efficiently solved. Finally, a pitch-axis nonlinear missile model is used to illustrate the effectiveness of the proposed method. [ABSTRACT FROM PUBLISHER]

During the process of oxidative phosphorylation, protons are pumped into the mitochondrial intermembrane space to establish a mitochondrial membrane potential (MMP). The electrochemical gradient generated allows protons to return to the matrix through the ATP synthase complex and generates ATP in the process. MitoQ is a lipophilic cationic drug that is adsorbed to the inner mitochondrial membrane; however, the cationic moiety of MitoQ remains in the intermembrane space. We found that the positive charges in MitoQ inhibited the activity of respiratory chain complexes I, III, and IV, reduced proton production, and decreased oxygen consumption. Therefore, a pseudo-MMP (PMMP) was formed via maintenance of exogenous positive charges. Proton backflow was severely impaired, leading to a decrease in ATP production and an increase in AMP production. Excess AMP activates AMP kinase, which inhibits the MTOR (mechanistic target of rapamycin) pathway and induces macroautophagy/autophagy. Therefore, we conclude that MitoQ increases PMMP via proton displacement with exogenous positive charges. In addition, PMMP triggered autophagy in hepatocellular carcinoma HepG2 cells via modification of mitochondrial bioenergetics pathways. [ABSTRACT FROM PUBLISHER]

This study was conducted to evaluate the adjuvant potential of sulfated Radix Cyathulae officinalis Kuan polysaccharides (sRCPS) and their effects on specific cellular and humoral immune responses to hepatitis B subunit vaccine in mice. Our data demonstrated that sRCPS significantly promoted the rHBsAg-specific IgG, IgG1, IgG2a, and IgG2b antibody titers, the activities of natural killer cells (NK) and cytotoxic T lymphocytes (CTL), T cells proliferation, and phagocytic capacity of peritoneal macrophages. Furthermore, sRCPS increased the levels of IL-4, IL-2, and IFN-γ in CD4+T cells and the level of IFN-γ in CD8+T cells. In addition, sRCPS enhanced the expression of CD40+, CD80+, CD86+, MHC I and MHC II in dendritic cells (DCs) and upregulated the mRNA levels of MHC I, MHC II. sRCPS downregulated the frequency of CD4+CD25+Foxp3+ Treg cells. sRCPS increased both cellular and humoral immune responses by upregulating DC maturation, and suppressing the frequency of Treg cells. [ABSTRACT FROM AUTHOR]