Thermodynamics and phase diagram of the binary system Bi2O3-B2O3

We analyzed the thermodynamic data of the binary system Bi₂O₃-B₂O₃. The phase diagram contains five compounds, of which four melt congruently, and a miscibility gap, close to pure B₂O₃. The three sets of transformation data of Bi₂O₃, the enthalpy of mixing data in the liquid, and the critical point of the miscibility gap gave five equations for the excess Gibbs energy of mixing and five sets of values for the enthalpies of formation of the binary compounds. The critical point data yielded another set of transformation data for Bi₂O₃. Using the monotectic composition and the enthalpy of mixing data also yielded a set of transformation data for Bi₂O₃. The values obtained using the enthalpy of mixing data are the most reliable values.     

Robust regulation with 2 performance

We consider the problem of minimizing the ₂ norm of a feedback system subject to the constraint that the controller robustly regulate against constants and sinusoids. We show that, for any ε > 0, there exists a controller that both achieves robust regulation and renders the closed-loop ₂ norm within ε of the optimal norm (the norm achievable without the robust regulation constraint). We also provide conditions that are both necessary and sufficient for there to exist a robustly regulating controller that achieves the optimal ₂ norm. All proofs are constructive.     

2 optimal control for sampled-data systems

This paper considers an ₂ optimal control problem for sampled-data systems. After defining a new ₂ norm for sampled-data systems, we give a state space solution to the optimal controller synthesis problem. We show that the ₂ optimal control problem for a sampled-data system is equivalent to a standard ₂ optimal control problem for a related discrete-time system.     

A new long-lasting phosphor Zr and Eu co-doped SrMg2(PO4)2

Zr⁴⁺- and Eu³⁺-codoped SrMg₂(PO₄)₂ phosphors were prepared by conventional solid-state reaction. Under the excitation of ultraviolet light, the emission spectra of Sr_0.95Eu_0.05Mg_2−2xZr_2xP₂O₈ (x = 0.0005-0.07) are composed of a broad emission band peaking at 500 nm from Zr⁴⁺-emission and the characteristic emission lines from the ⁵D₀ → ⁷F_J (J = 0, 1, 2, 3 and 4) transitions of Eu³⁺ ions. These phosphors show the long-lasting phosphorescence. The emission color varies from red to white with increasing Zr⁴⁺-content. The white-light emission is realized in single-phase phosphor of Sr_0.95Eu_0.05Mg_2−2xZr_2xP₂O₈ (x = 0.07) by combining the Zr⁴⁺- and Eu³⁺-emission. The duration of the persistent luminescence of Sr_0.95Eu_0.05Mg_2−2xZr_2xP₂O₈ (x = 0.07) reaches nearly 1.5 h. The time at which the long-lasting phosphorescence intensity is 50% of its original value (T_0.5) is 410 s. The afterglow decay curves and the thermoluminescence spectra were measured to discuss this long-lasting phosphorescence phenomenon. The co-doped Zr⁴⁺ ions act as both the luminescence centers and trap-creating ions.     

Production of singlet oxygen by Ru(dpp(SO3)2)3 incorporated in polyacrylamide PEBBLES

Polyacrylamide (PAA) and amine-functionalized PAA (AFPAA) nanoparticles with disulfonated 4,7-diphenyl-1,10-phenantroline ruthenium (Ru(dpp(SO₃)₂)₃) have been prepared. The nanoparticles produced have a hydrodynamic radius of 20–25 nm.

The amount of singlet oxygen (¹O₂) produced by Ru(dpp(SO₃)₂)₃ as been measured using anthracene-9,10-dipropionic acid (ADPA). A kinetic model for the disappearance of ADPA, by steady state irradiation of Ru(dpp(SO₃)₂)₃ at 465 nm, has been developed taking also into account a consumption not mediated by ¹O₂. This direct consumption of ADPA is evaluated by irradiating in the presence of NaN₃ and is about 30% of the total. All the experimental results are very well described by the model developed, both for free Ru(dpp(SO₃)₂)₃ and with this dye incorporated in the nanoparticles.

It is found that the polyacrylamide matrix does not quench the ¹O₂ produced, allowing it to reach the external solution of the nanoparticles and react with ADPA. When the matrix possesses amine groups, AFPAA, the amount of ¹O₂ that reacts with ADPA is slightly reduced, 60%, but most of the ¹O₂ produced can still leave the particles and react with external molecules. The particles produced may therefore be used as sources of ¹O₂ in photodynamic therapy (PTD) of cancers. The fact that those nanoparticles do not quench significantly the ¹O₂ makes possible the future development of ¹O₂ sensors based on PAA nanoparticles with the appropriate sensor molecule enclosed.     

The next 10,0002 years. II

For pt.I see ibid., vol.4, p.64-70 (1996). As microprocessor advances begin to level off, communication network deployment will keep accelerating, and software engineering must face the prospect of radical change if it is to keep pace. The paper considers how the intersection of these ascending and descending technologies will propel the high-tech world into a new model of computing by the year 2012. Software is the steam that drives the engines of the Information Age, but clearly it is not keeping up with developments on the hardware side. Historical trends suggest that further progress in programmer productivity and programming-language power over the next 10,000₂ years is highly unlikely. With a large percentage of programmers maintaining legacy code, the resources available for innovation are limited. In fact, software innovation will have to come from a five percent fringe of artisans and nontraditional thinkers outside the current programming language and software engineering establishment     

The next 10,0002 years. I

Forecasts technological breakdowns and breakthroughs for the next 16 (10,000 to the base 2) years. Change has always been a part of recent history. Indeed, Earth-shaking change occurs about every 150-200 years. It takes about 50 years to make the transition from the old to the new, and we are nearing the end of just such a 50-year period. Change is caused by both technological breakthroughs and technological breakdowns. In the current 50-year transition, the breakthrough is in networking and software development, and the breakdown is in processor (VLSI) technology. Both forces will propel the high-tech world into a new model of computing by the year 2012. The new model will be based on a networked, global megacomputer that obeys the Gustafson-Barsis speedup law instead of the Amdahl law of parallelism. The next century's information superhighway will actually be a network of cable TV operators, not telephone companies. A new era of programming that eliminates traditional programming languages (and scolds the software engineering community for failure) will arise and lead to a software economy-an electronic commerce dominated by software artisans     

Synthesis of positive real ℋ2 controllers

This paper describes a synthesis procedure for strictly positive real observer-based controllers. In particular, we address the standard ℋ₂-optimal control problem with the additional constraint on the strict positive realness of the controller. A suboptimal version of this problem is shown to be a convex optimization problem, and a linear matrix inequality-based solution is provided. One example illustrates the main results     

On the 2-induced norm of a sampled-data system

Formulas are given for the norms of SG and GH: G is a linear continuous-time system, S an ideal sampler, and H a zero-order hold; the signal spaces are ₂(−∞, ∞) (continuous-time) and l₂(Z) (discrete-time). These formulas are then applied to problems of uniformly optimal control of sampled-data systems.     

Solubility prediction for the nonelectrolyte urea–hydrogen peroxide–water system and thermodynamic solubility product calculation for CO(NH2)2 ⋅ H2O2 using the modified Pitzer model

The Pitzer interaction model, which has been applied successfully to the thermodynamic simulation of electrolyte solutions and electrolyte–nonelectrolyte solutions, was extended to nonelectrolyte–nonelectrolyte solution system. In the present work, the modified Pitzer model was used for calculation and correlation of the ternary CO(NH₂)₂–H₂O₂–H₂O system at 283.15 K. The value of the Pitzer interaction parameters for the ternary system and the thermodynamic solubility product of CO(NH₂)₂⋅H₂O₂ were determined using a least-square optimization procedure with coupling activity coefficient and solubility data. The predicted isothermal solubilities agree well with the result obtained from the experiment. The results indicated that the modified Pitzer model could be successfully used to predict the component solubility of the nonelectrolyte–nonelectrolyte system.     

Thermodynamic modeling of the LiCoO2-CoO2 pseudo-binary system

The thermodynamic modeling of the LiCoO₂-CoO₂ pseudo-binary system, a positive electrode material of Li-ion batteries, was performed using the CALPHAD technique. The O3-LiCoO₂ and the O1-CoO₂ phases were described using the four-sublattice model with the formula (Li,V a)_1/2(Li,V a)_1/2(Co)₁(O)₂, and the three-sublattice model with the formula (Li,V a)₁(Co)₁(O)₂. The H1_3 hybrid phase was treated as a non-stoichiometric compound. The thermodynamic quantities, such as the phase equilibria, formation enthalpies and cell voltage (vs. Li/Li⁺), were in agreement with data reported in the literature.     

编码曝光图像的L0正则化去模糊重建方法

目标的运动会导致其成像模糊。为了从模糊的图像中恢复清晰的目标图像,本文采用了编码曝光成像技术。与传统相机成像中快门一直处于开启的状态不同,编码曝光相机成像是在快门开启和闭合转换过程中成像。由于在时域快速转换的编码等效为频域较宽的滤波器,因此编码曝光成像有效地保留了目标的高频信息。为了从编码曝光图像中清晰地复原图像,本文设计了能保留图像高频细节的L ₀正则项约束的图像重建和模糊核估计方法。通过待重建图像与模糊核的交替迭代更新来完成图像重建。仿真合成图像和实际采集图像的实验表明,本方法对多种运动产生的模糊均有良好的图像复原效果。     

On ?∞, robust stability and performance with ?2 and ?∞ perturbations

In this paper we will consider systems with linear time-invariant perturbations. We will analyze robust performance in the ?₂ and ?_∞ settings. The ?₂ setting gives rise to the familiar case of structured singular values, and a stability criterion is given by the “small μ” theorem. We show that although the necessary and sufficient criterion of robust stability for the ?_∞ case (?_∞ stability with structured ?_∞-gain bounded perturbations) is the same “small μ” criterion, a system with ?₂-gain bounded perturbations is never ?_∞ stable.     

MIMO optimal control design: the interplay between the ℋ2 and the l1 norms

We consider controller design methods which can address directly the interplay between the ℋ2 and l₁ performance of the closed loop. The development is devoted to multi-input/multi-output (MIMO) systems. Two relevant multi-objective performance problems are considered each being of interest in its own right. In the first, termed as the combination problem, a weighted sum of the l₁ norms and the square of the ℋ₂ norms of a given set of input-output transfer functions constituting the closed loop is minimized. It is shown that, in the one-block case, the solution can be obtained via a finite-dimensional quadratic optimization problem which has an a priori known dimension. In the four-block case, a method of computing approximate solutions within any a priori given tolerance is provided. In the second, termed as the mixed problem, the ℋ₂ performance of the closed loop is minimized subject to an l₁ constraint. It is shown that approximating solutions within any a priori given tolerance can be obtained via the solution to a related combination problem     

2 guaranteed cost control for uncertain continuous-time linear systems

This paper proposes a solution to the ₂ guaranteed cost control problem for uncertain, continuous-time linear systems. It consists of the determination of a constant state feedback stabilizing matrix gain and a ₂-norm upper bound, valid for all feasible models. The uncertainties are only assumed to be convex-bounded, a concept which generalizes the important case of interval matrices uncertainties. The results follow from a new parameterization of all stabilizing gains over a convex set. As an additional property, the above mentioned ₂-norm upper bound reduces to the minimum ₂ cost in case of precisely known linear systems.     

Thermodynamic assessment of the KCl–K2CO3–NaCl–Na2CO3 system

Phase equilibria and thermodynamic properties of the KCl–K₂CO₃–NaCl–Na₂CO₃ system were analyzed on the basis of the thermodynamic evaluation of the KCl–NaCl,KCl–K₂CO₃,NaCl–Na₂CO₃,K₂CO₃–Na₂CO₃ and KCl–K₂CO₃–NaCl–Na₂CO₃ systems. The Gibbs energies of individual phases was approximated by two-sublattice models for ionic liquids and crystals. Most of the experimental information was well described by the present set of thermodynamic parameters. The lowest monovariant eutectic temperature in the KCl–NaCl–Na₂CO₃ system is located at 573 ^°C, with a composition of X_Na2CO3=0.31,X_KCl=0.35 and X_NaCl=0.34.     

Mixed ℋ2 and ℋ∞ performanceobjectives. II. Optimal control

This paper considers the analysis and synthesis of control systems subject to two types of disturbance signals: white signals and signals with bounded power. The resulting control problem involves minimizing a mixed ℋ₂ and ℋ_∞ norm of the system. It is shown that the controller shares a separation property similar to those of pure ℋ₂ or ℋ_∞ controllers. Necessary conditions and sufficient conditions are obtained for the existence of a solution to the mixed problem. Explicit state-space formulas are also given for the optimal controller     

Connections between minimum entropy control and mixed 2/ ∞ control for time-varying systems

In this paper two properties of minimum entropy control for linear time-varying systems are investigated. An entropy formulation for anti-causal systems is first considered. Minimizing the norm of an anticausal system is straightforward because of the fact that the norm of an operator is equal to the norm of its adjoint. This is not true for the entropy measure. For this reason a separate formula for the entropy of anti-causal systems is needed in order to consider dual problems that arise in optimal control theory. Secondly, we investigate the relationship between the entropy measure for time-varying systems and the ₂ and _∞ norms. For time-invariant systems, minimum entropy control has been shown to be a good mixed ₂/ _∞ controller. In this paper we show that this is also true in the time-varying case.     

Water activities, osmotic and activity coefficients of the system (NH4)2SO4–K2SO4–H2O at the temperature 298.15 K

The mixed aqueous electrolyte system consisting of ammonium and potassium sulfates has been studied using the hygrometric method at the temperature 298.15 K. The water activities are measured at total ionic strength values ranging from 0.60 to 8.25 mol kg⁻¹ for different ionic strength fractions (y) of (NH₄)₂SO₄ with y=0.20, 0.50 and 0.80. The obtained data allow the deduction of osmotic coefficients. The experimental results are compared with the predictions of the Zdanovskii–Stokes–Robinson (ZSR), Kusik and Meissner (KM), Robinson and Stokes (RS), Lietzke and Stoughton (LS II), Reilly–Wood and Robinson (RWR) and Pitzer models. From these measurements, the new Pitzer mixing ionic parameters are determined and used to predict the solute activity coefficients in the mixture.