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The remains of stone material in religious architectures in Thanh Hoa are relatively significant today, scattered in temples, mausoleums, and ancient citadels. However, stone worshiping objects account for a small number compared to relics such as horse statues, elephant statues, tiger statues, animal spirits, and human statues and are in danger of being lost or destroyed. Researching stone worshiping objects in religious relics to get an overview of one of the special types of relics as well as propose some necessary measures to preserve and promote their values properly. cultural property left by our forefathers.

Scientific research for university lecturers plays an important role in training creative thinking ability, research capacity and scientific working style for researchers. This contributes to clarifying some scientific issues and solving practical problems that arise in order to improve the quality of teaching. This article focuses on analyzing some issues about the role of scientific research for university lecturers today.

In-Situ composite materials of graphene (Gr) and ZnO microspindle with different Gr contents (1, 2 and 5 wt.%) were prepared via a facile one-step hydrothermal route with the assistance of hexamethylenetetramine. Graphene does not affect the hexagonal wurtzite crystal structure of composite materials but strongly affects the morphological, structural, optical and photocatalytic properties of composite materials. In detail, Gr causes a decrease in both the dimensions of ZnO microspindle and photoluminescence efficiency. The average crystalline size and microstrain first increase from 28.9 nm and 0.00394 to 49.5 nm and 0.00524 when Gr content increases from 0 to 1 wt.%, respectively; then decrease to 39.6 nm and 0.00404 when Gr content increase from 1 to 5 wt.%, respectively. Both pristine and composite materials show high photocatalytic activity with high methylene blue degradation efficiency?more than 90%-just after 40 min under UV irradiation. Composite material having a Gr content of 5 wt.% shows the highest degradation efficiency of 96.5% which confirms the role of Gr in enhancing the photocatalytic activity of ZnO.

g-C3N4@WO3.H2O nanoplate composite adsorbents were prepared in a simple acid precipitation method at room temperature. The g-C3N4@WO3.H2O nanoplate composite adsorbents were characterized by X-ray powder diffraction, micro-Raman spectroscopy, Fourier transform infrared spectra, scanning electron microscopy and UV-vis diffuse reflectance spectroscopy. The results show that the orthorhombic-phase WO3.H2O nanoplates with dimensions of [Formula: see text][Formula: see text]nm3 were successfully composited with g-C3N4. The methylene blue dye generation activity of these adsorbents was evaluated. The kinetics and absorption model of g-C3N4@WO3.H2O nanoplate composite adsorbents were further studied.

The NiTiO3 ceramic was synthesized in nanostructured form by citrate gel method. The phase structure, microstructure and magnetic properties of synthesized compounds were investigated by X-ray diffraction (XRD), scanning electron microscope and vibrating sample magnetometer. Williamson–Hall plot was used to calculate the crystallite size and microstrain of sample. The XRD analysis showed the formation of rhombohedral crystal structure of synthesized powders. The crystallite size is about 35[Formula: see text]nm and microstrain is [Formula: see text]. The optical band gap was estimated from UV-Visible spectrum with value of 2.43[Formula: see text]eV. The NiTiO3 samples showed coexistence of ferroelectric and antiferromagnetic properties at room temperature.

Let q be a prime power, and Fq be the finite field of order q. In this short note, by using methods from spectral graph theory, we give sufficient conditions to guarantee that Fq \ {0}  {a1u1x1 + ••• + adudxd : 1 ≤ xi ≤ Mi; 1 ≤ i ≤ d} ; where ai and ui are non-zero elements in Fq, and Mi are integers. This result generalizes a recent result given by Cilleruelo and Zumalacarregui (2014). Using the same techniques, we extend this result in the setting of the finite cyclic ring.

We study a variant of Erdős–Rényi graph over finite rings. We then use this graph to obtain a Szemerédi–Trotter type theorem a sum-product estimate in finite rings.

In this paper, we use methods from spectral graph theory to obtain some results on the sum-product problem over finite valuation rings $\mathcal{R}$ of order $q^r$ which generalize recent results given by Hegyv\'ari and Hennecart (2013). More precisely, we prove that, for related pairs of two-variable functions $f(x,y)$ and $g(x,y)$, if $A$ and $B$ are two sets in $\mathcal{R}^*$ with $|A|=|B|=q^\alpha$, then \[\max\left\lbrace |f(A, B)|, |g(A, B)| \right\rbrace\gtrsim |A|^{1+\Delta(\alpha)},\] for some $\Delta(\alpha)>0$., Comment: To appear in European Journal of Combinatorics

International audience; Cet article traite de la commande pr edictive pour un syst eme lin eaire hyperbolique de lois de conservation. Une preuve compl ete de la stabilit e exponentielle du syst eme boucl e avec cette commande est etablie. L'approche de semi-groupe est utilis ee pour prouver l'existence et l'unicit e de la solution optimale. La fonction de co^ut de la commande optimale est inspir ee de la fonction de Lyapunov propos ee pr ec edemment par Coron et al. (2009) pour les syst emes hyperboliques. Gr^ace a ce choix, la stabilit e exponentielle du syst eme boucl e est prouv ee. Pour la mise en oeuvre, le calcul variationnel est utilis e pour d eriver les etats adjoints du syst eme et la m ethode de Boltzmann sur r eseaux est utilis ee pour r esoudre a la fois des equations aux d eriv ees partielles directes et adjointes . Cette approche est nalement valid ee en simulation.

International audience

International audience; In this work we investigate the predictive control problem for partial di erential equations interconnected through their boundary conditions. More speci cally, we consider systems of cascaded 1D hyperbolic equations. The main obstacle for applying model predictive control methodologies for such systems is the huge computational e ort required to solve the corresponding optimization problems. Therefore, we present some results on decomposition methods. The obtained sub-problems are solved in parallel and considered as subsystems controlled by decentralized interacting agents. The proposed approach is validated in simulation for a free surface water transportation system made of interconnected canal reaches interconnected through actuated gates.

Let $\mathbb{F}_q$ be a finite field of $q$ elements where $q$ is a large odd prime power and $Q =a_1 x_1^{c_1}+...+a_dx_d^{c_d}\in \mathbb{F}_q[x_1,...,x_d]$, where $2\le c_i\le N$, $\gcd(c_i,q)=1$, and $a_i\in \mathbb{F}_q$ for all $1\le i\le d$. A $Q$-sphere is a set of the form $\lbrace x\in \mathbb{F}_q^d | Q(x-b)=r\rbrace$, where $b\in \mathbb{F}_q^d, r\in \mathbb{F}_q$. We prove bounds on the number of incidences between a point set $\mathcal{P}$ and a $Q$-sphere set $\mathcal{S}$, denoted by $I(\mathcal{P},\mathcal{S})$, as the following. $$| I(\mathcal{P},\mathcal{S})-\frac{|\mathcal{P}||\mathcal{S}|}{q}|\le q^{d/2}\sqrt{|\mathcal{P}||\mathcal{S}|}.$$ We prove this estimate by studying the spectra of directed graphs. We also give a version of this estimate over finite rings $\mathbb{Z}_q$ where $q$ is an odd integer. As a consequence of the above bounds, we give an estimate for the pinned distance problem. In Sections $4$ and $5$, we prove a bound on the number of incidences between a random point set and a random $Q$-sphere set in $\mathbb{F}_q^d$. We also study the finite field analogues of some combinatorial geometry problems, namely, the number of generalized isosceles triangles, and the existence of a large subset without repeated generalized distances., Comment: to appear in Forum Math

International audience; This paper presents some state reconstruction scheme for a class of in nite dimensional systems, from the only knowledge of boundary conditions. The considered model is typical of convection-di usion processes with possible additional reaction phenomenon. The state reconstruction is based on a simple boundary output injection and a full convergence analysis. The robustness of the estimation with respect to modeling errors is also discussed. It is shown that if one employs more sensors to get more measurements, the robustness can be reinforced. An illustrative example with pollutants transport problem is presented accordingly. The proposed approach is nally validated in simulation by using the newly developed Lattice Boltzmann Method.

International audience; This paper presents an infinite-dimensional Receding Horizon Observer for linear 2x2 hyperbolic systems with boundary measurements. The initial state is estimated as the optimal solution of an optimization problem which minimizes the distance between the measurements and the observer output. A constructive method is used to derive the existence and uniqueness of the solution. A composite strategy combining Receding Horizon Optimal Control and Receding Horizon Observer is also presented. Its effectiveness in guaranteeing closed-loop stability is also demonstrated. For the implementation, the calculus of variation approach is used to derive the adjoint state which will be discretized and solved with the observer state to obtain the optimal solution. Finally, a simulation with a linearized model of an open-channel system is carried out to validate the here-proposed approach.

International audience; This paper presents a Receding Horizon Optimal Control (RHOC) scheme with zero terminal constraint, to guarantee the stability of linear 2x2 hyperbolic systems with boundary control. The boundary control problem is first reformulated into the abstract form in which the existence and the explicit formulation of the optimal control were established in the literature. These results are then applied in the RHOC scheme to give a complete proof of stability of the closedloop system. For the implementation, the calculus of variation approach is used to derive the adjoint state which will be discretized and solved with the state to obtain the optimal control. It turns out that this optimal solution is a function of the state and can be implemented in a feedback form. Finally, a simulation is carried out to validate the here-proposed approach.

ZnS:Mn nanoparticles were synthesized by co-precipitation method from the precursors solutions of 0.1M Zn(CH\(_{3}\)COO)\(_{2}\), Na\(_{2}\)S and Mn(CH\(_{3}\)COO)\(_{2}\) then were capped with polyvinyl pyrrolidone. The XRD patterns showed that the ZnS:Mn nanoparticles possessed the \(T_d^2 - F4\bar {3}m\) cubic structure with the average crystallite size of several nanometers. At 300~K, the obtained photoluminescence spectra showed only a wide yellow-orange band centered at 603 nm, which should be attributed to the radiation transition of [\(^{4}\)T\(_{1}(^{4}\)G)\( \to ^{6}\)A\(_{1}(^{6}\)S)] of Mn\(^{2 + }\)(3d\(^{5})\) cations in the ZnS matrix. The excitation spectra recorded at 300 K on the other hand featured a strong photoluminescence band around 310-334 nm, which were assigned to the near band-edge absorption transition of ZnS host lattice, in addition with three weaker bands relating to the absorption transitions of [\(^{6}\)A\(_{1}(^{6}\)S) \( \to \) \(^{4}\)T\(_{2}(^{4}\)D)]: 430 nm, [\(^{6}\)A\(_{1}(^{6}\)S) \( \to \) \(^{4}\)A\(_{1}(^{4}\)G) -- \(^{4}\)E(\(^{4}\)G)]: 468 nm, and [\(^{6}\)A\(_{1}(^{6}\)S) \( \to ^{4}\)T\(_{2}(^{4}\)G)]: 498 nm of Mn\(^{2 + }\)(3d\(^{5})\) cations. It was shown that the capping affected only the intensities of emissions bands.

The predictive control or Receding Horizon Optimal Control (RHOC) is becoming increasingly popular in many practical applications due to its significant advantages such as the stabilization and constraints handling. It has been well studied for finite dimensional systems even in the nonlinear case. However, its extension to infinite dimensional systems has not received much attention from researchers. This thesis proposes contributions on the application of this approach to systems of conservation laws. We present a complete proof of stability of RHOC for some classes of infinite dimensional systems. This result is then used for 2x2 hyperbolic systems with boundary control, and applied to an irrigation canal. We also propose the extension of this strategy to networks of cascaded 2x2 hyperbolic systems with an application to a set of connected irrigation canals. Furthermore, we study the benefits of RHOC in the context of nonlinear and semi-linear systems in particular with respect to the problem of shocks. All theoretical analyzes are validated by simulation in order to illustrate the effectiveness of the proposed approach.; La Commande prédictive ou Commande Optimale à Horizon Glissant (COHG) devient de plus en plus populaire dans de nombreuses applications pratiques en raison de ses avantages importants tels que la stabilisation et la prise en compte des contraintes. Elle a été bien étudiée pour des systèmes en dimension finie même dans le cas non linéaire. Cependant, son extension aux systèmes en dimension infinie n'a pas retenu beaucoup d'attention de la part des chercheurs. Ce travail de thèse apporte des contributions à l'application de cette approche aux systèmes de lois de conservation. Nous présentons tout d'abord une preuve de stabilité complète de la COHG pour certaines classes de systèmes en dimension infinie. Ce résultat est ensuite utilisé pour les systèmes hyperboliques 2x2 commandés aux frontières et appliqué à un problème de contrôle de canal d'irrigation. Nous proposons aussi l'extension de cette stratégie au cas de réseaux de systèmes hyperboliques 2x2 en cascade avec une application à un ensemble de canaux d'irrigation connectés. Nous étudions également les avantages de la COHG dans le contexte des systèmes non linéaires et semi-linéaires notamment vis-à-vis des chocs. Toutes les analyses théoriques sont validées par simulation afin d'illustrer l'efficacité de l'approche proposée.

The predictive control or Receding Horizon Optimal Control (RHOC) is becoming increasingly popular in many practical applications due to its significant advantages such as the stabilization and constraints handling. It has been well studied for finite dimensional systems even in the nonlinear case. However, its extension to infinite dimensional systems has not received much attention from researchers. This thesis proposes contributions on the application of this approach to systems of conservation laws. We present a complete proof of stability of RHOC for some classes of infinite dimensional systems. This result is then used for 2x2 hyperbolic systems with boundary control, and applied to an irrigation canal. We also propose the extension of this strategy to networks of cascaded 2x2 hyperbolic systems with an application to a set of connected irrigation canals. Furthermore, we study the benefits of RHOC in the context of nonlinear and semi-linear systems in particular with respect to the problem of shocks. All theoretical analyzes are validated by simulation in order to illustrate the effectiveness of the proposed approach., La Commande prédictive ou Commande Optimale à Horizon Glissant (COHG) devient de plus en plus populaire dans de nombreuses applications pratiques en raison de ses avantages importants tels que la stabilisation et la prise en compte des contraintes. Elle a été bien étudiée pour des systèmes en dimension finie même dans le cas non linéaire. Cependant, son extension aux systèmes en dimension infinie n'a pas retenu beaucoup d'attention de la part des chercheurs. Ce travail de thèse apporte des contributions à l'application de cette approche aux systèmes de lois de conservation. Nous présentons tout d'abord une preuve de stabilité complète de la COHG pour certaines classes de systèmes en dimension infinie. Ce résultat est ensuite utilisé pour les systèmes hyperboliques 2x2 commandés aux frontières et appliqué à un problème de contrôle de canal d'irrigation. Nous proposons aussi l'extension de cette stratégie au cas de réseaux de systèmes hyperboliques 2x2 en cascade avec une application à un ensemble de canaux d'irrigation connectés. Nous étudions également les avantages de la COHG dans le contexte des systèmes non linéaires et semi-linéaires notamment vis-à-vis des chocs. Toutes les analyses théoriques sont validées par simulation afin d'illustrer l'efficacité de l'approche proposée.

International audience; This paper deals with the boundary control for scalar non-linear hyperbolic systems of conservation laws. One of the issues arising from these systems is the formation of the singularities (called shocks) in the domain. We will show that to avoid the shock, a set of constraints for the control and the state at the boundary has to be ful lled. Then, a proof of the exponential stability of the system is established provided that there is no shock and that the state at the boundary is exponentially stable. These conditions are shown to be achieved by the Receding Horizon Optimal Control approach. A simulation is nally carried out with the freeway tra c model to demonstrate the potential of here-proposed control.

International audience; The D1Q3 lattice Boltzmann (LB) shallow water equation is analyzed in detail and compared with other numerical schemes. Analytical results are derived and used to discuss the accuracy and stability of the model. We show how such D1Q3 LB models for canal reaches may be easily coupled with various hydraulic interconnection structures to build models of complex irrigation networks.

For the first time, hematite nanorods were successfully synthesised using iron nitrate precursors in the presence of cation SO4−2. This is also the first time that an investigation into hematite nanorods behaviour for hydrogen fuel storage has been carried out. Microspheres constructed with α-FeOOH nanorods were synthesised via a novel hydrothermal method using a mixture of Fe(NO3)3 · 4H2O and Na2SO4 as the initial material. The α-FeOOH was transformed into hematite (α-Fe2O3) nanorods through an annealing process at 600°C for 2 h. The influence of different anions on the formation of hematite α-Fe2O3 nanorods was investigated. Experimental results proved that the addition of Na2SO4 solution controlled the morphology of α-Fe2O3. Its structure and morphology were investigated using XRD, SEM and Raman techniques. The kinetic curve of hydrogen generation of some hematite morphology samples was examined by redox cycle and the hydrogen fuel was formed by oxidation with water vapour. Although the nanorod morphology of hematite samples was damaged during redox cycles, the samples demonstrated high activity for hydrogen generation in comparison with precipitation and sol gel samples. The ratio of H2/Fe of nanorod samples for two redox cycles was 1.91% and 1.76%, respectively. Thus, hematite nanorods are a promising material for storage of hydrogen fuel.

Background Despite the increasing prevalence of type 2 diabetes in urban areas, relatively little has been known about its actual prevalence and its associations in rural areas, Vietnam. The purpose of this study was to evaluate the prevalence of impaired fasting glucose (IFG), impaired glucose tolerance (IGT), diabetes and their risk factors in a rural province, Vietnam. Methods A cross–sectional study with a representative sample was designed to estimate the hyperglycemia prevalence, using 75–g oral glucose tolerance test. Potential risk factors for hyperglycemia were analyzed using multinomial logistic regression, taken into account influences of socio–economic status, anthropometric measures, and lifestyle–related factors. Results The age and sex–adjusted prevalence rates (95% CI) of isolated IFG, isolated IGT, combined IFG–IGT, and diabetes were 8.7 (7.0–10.5), 4.3 (3.2−5.4), 1.6 (0.9−2.3), and 3.7% (2.7–4.7%), respectively. There were still 73% of diabetic subjects without knowing the condition. Blood pressure, family history of diabetes, obesity–related measures (waist circumference, waist–hip ratio, body fat percentage, and abdominal obesity) were the independent risk factors for hyperglycemia (IFG, IGT, and diabetes). Conclusions The prevalence of hyperglycemia in rural areas has not been as sharply increased as that reported in urban cities, Vietnam. Blood pressure and obesity–related measures were the most significant predictors for hyperglycemia level and they can be taken into account in building prognosis models to early detection of diabetes in rural Vietnamese populations.

In this thesis we study a number of problems in Discrete Combinatorial Geometry in finite spaces. The contents in this thesis are structured as follows: In Chapter 1 we will state the main results and the notations which will be used throughout the thesis. Chapter 2 is a version of the paper entitled "Sumsets of the distance sets in finite spaces", which has been submitted for publication, (2017). Chapter 3 is a version of the paper entitled "Three-variable expanding polynomials and higher-dimensional distinct distances", which has been submitted for publication, co-authored with L. A. Vinh and de Zeeuw. The author was one of the main investigators of this chapter. Chapter 4 is a postprint version of the paper entitled "Distinct distances on regular varieties over finite fields", Journal of Number Theory, 173(2017), 602-613, co-authored with D. D. Hieu. The author was one of the main investigators of this chapter. Chapter 5 is a postprint version of the paper entitled " Incidences between points and generalized spheres over finite fields and related problems", Forum Mathematicum, Volume 29, Issue 2 (Mar 2017), co-authored with N. D. Phuong and L. A. Vinh. The author was one of the main investigators of this chapter. Chapter 6 is a version of the paper entitled "Distinct spreads in finite spaces", which has been submitted for publication, co-authored with B. Lund and L. A. Vinh. The author was one of the main investigators of this chapter. Chapter 7 is a version of the paper entitled "Paths in pseudo-random graphs", which has been submitted for publication, co-authored with L. A. Vinh. The author was one of the main investigators of this chapter. Chapter 8 is a version of the paper entitled "Conditional expanding bounds for two-variable functions over arbitrary fields", which has been submitted for publication, co-authored with Hossein Nassajian Mojarrad. The author was one of the main investigators of this chapter. Chapter 9 is a postprint version of the paper entitled "A Szemeredi-Trotter type theorem, sum-product estimates in finite quasifields, and related results", Journal of Combinatorial Theory Series A, 147(2017), 55-74, co-authored with Michael Tait, Craig Timmons, Le Anh Vinh. The author was one of the main investigators of this chapter. The content of this chapter also appears in Michael Tait's Phd thesis. In Chapter 10, we will mention some open problems on Erd\H{o}s distinct distances problem and generalizations.

International audience; This paper deals with the Predictive Control for a linear hyperbolic system of conservation laws. A complete proof of the exponential stability of this control is established. The semi-group approach is used to prove the existence and uniqueness of the optimal solution. The cost function of the optimal control is inspired from the previously proposed candidate Lyapunov function for hyperbolic systems. Thanks to this choice, the exponential stability of the control is proven. For the implementation, calculus of variations is used to derive the adjoint state of the system and the recently proposed {\em Lattice Boltzmann method} is used to solve both direct and adjoint partial differential equations. This approach is finally validated in simulation.