Electrodeposition of Si–DLC nanocomposite film and its electronic application

Microsystem Technologies - In this study, a silicon doped diamond-like carbon (DLC) nanocomposite film was deposited electrochemically and it was used to fabricate an Ag/Si–DLC/p-Si...     

Low temperature solid–liquid interdiffusion wafer and die bonding based on PVD thin Sn/Cu films

Microsystem Technologies - Cu–Sn intermetallic diffusion has been studied with thin Sn and Cu films deposited by physical vapor deposition. It was found that annealing time is critical to the...     

Boundary model predictive control of thin film thickness modelled by the Kuramoto–Sivashinsky equation with input and state constraints

In this work, a model modal predictive control (MMPC) strategy is proposed to stabilize the falling liquid film thickness in the vertical tubes modelled by the Kuramoto–Sivashinsky (K–S) equation in the presence of naturally present state and input constraints. The novel features of proposed synthesis is the development of an infinite dimensional PDE state representation which incorporates the exact transformation of boundary into the distributed control setting and benefits arising from the property of decoupled boundary applied input actuation and K–S PDE modal states. Furthermore, the dissipative structure of the K–S spectral operator provides the foundation for the model modal based predictive controller (MMPC) synthesis which utilizes the finite dimensional state representation to formulate the quadratic objective function while the infinite dimensional K–S PDE state constraints are appropriately defined and cast in the form of a constrained quadratic programme. Finally, we demonstrate that if feasible, the MMPC achieves stabilization of the thin film thickness and satisfies naturally present state and input constraints. Numerical simulation of the boundary applied actuation evaluates the proposed method's performance.     

Formation of CaZrO3 at the interface between CaO–SiO2–MgO–CaF2(–ZrO2) slags and magnesia refractories: Computational and experimental study

The formation behaviour of calcium zirconate (CaZrO₃) at the interface between the CaO–SiO₂–MgO–CaF₂(–ZrO₂) slags (B$B$(=(mass% CaO) /(mass% SiO₂)) = 2.0) used in the AOD converter and the MgO refractories has been computed by employing a commercial thermodynamic software. The solubility of zirconia (ZrO₂) in the liquid CaO–SiO₂-7 mass% MgO slag phase is relatively small, viz. about 2–3 mass% and the CaZrO₃ phase is formed at about B>1.5$B>1.5$. The region of fully liquid phase extends to the composition saturated by dicalcium silicate (Ca₂SiO₄) and cubic ZrO₂ (B∼1.2$B\sim 1.2$). The effect of 7 mass% CaF₂ addition on the solubility of ZrO₂ in the liquid slag phase was computed to be negligible, while the liquid phase exists through the entire compositions. In addition, the region of fully liquid phase extends to the more basic composition range (B∼1.5$B\sim 1.5$), where the saturating phases are the Ca₂SiO₄ and CaZrO₃. The thermodynamic calculations indicate CaZrO₃ not to form at (mass% ZrO₂) /(mass% MgO) ((=Z/M))<0.6. In the “ Liquid+Ca₂SiO₄+MgO” region, the activity of SiO₂ in the liquid phase is nearly fixed because the activity of CaO in the liquid phase is unaffected by the activity of ZrO₂. However, with higher ZrO₂ activity from the increase in the Z/M ratio, the activity of CaO in the liquid phase is expected to decrease due to the formation of CaZrO₃. The formation behaviour of CaZrO₃ in the slags, computed based on the Gibbs energy minimization principles, could experimentally be confirmed by employing the XRD and SEM–EDS analysis.     

Spatial–temporal land-use/land-cover dynamics and their impacts on surface temperature in Chongming Island of Shanghai,China

Land-use/land-cover (LULC) changes are occurring at rapid rates on the Chongming Island of Shanghai, China, giving rise to a major concern about environmental impacts. We herein carried out a sound analysis of the LULC dynamics, the conversions among different LULC classes, and land-surface temperature (LST) distribution using remote-sensing data from Landsat Multispectral Scanner (MSS), Thematic Mapper (TM), and Enhanced Thematic Mapper Plus (ETM+) time series spanning the last 35 years (1979–2014). Based on LULC class information and LST, we constructed a temperature/vegetation index space to study the temporal variability of thermal data, vegetation cover, and LULC. The results showed that the LULC change dynamics in Chongming Island have strongly impacted the LST in the recent decade. The spatial position conversion and quantitative change of vegetation cover totalled about 44.4% of LULC-type areas over the Island, and the comprehensive LULC dynamicity changed from 2.97 to 3.95 during the investigated period. Accordingly, significant LST changes took place in the portion of the Chongming Island showing normal temperature range, which accounted for 85.94% of the whole Island’s area as of 1 August 2000 and that decreased to 50.79% on 6 May 2009, while the surface extents under low- and with ultra-high-temperature ranges increased, respectively, both from 0 of 2000 to 6.67% and 0.41% of 2009. The results indicate that the pixel classes including vegetation cover, wetland, and waterbody, which have larger dynamicity and maximum change vector magnitudes, played a large role in alleviating the effect of the land-surface thermal environment, and were key driving factors contributing to the increasing trend of non-normal temperature range ratio over time. Our findings are expected to provide valuable information for decision-making regarding the development and construction of Chongming Island into an eco-region.     

On the ?2 stability of time varying linear and nonlinear discrete time MIMO systems

New conditions are derived for the l2-stability of time-varying linear and nonlinear discrete-time multiple-input multipleoutput （MIMO） systems, having a linear time time-invariant block with the transfer function F（z）, in negative feedback with a matrix of periodic/aperiodic gains A（k）, k = 0,1, 2,... and a vector of certain classes of non-monotone/monotone nonlinearities φp（-）, without restrictions on their slopes and also not requiring path-independence of their line integrals. The stability conditions, which are derived in the frequency domain, have the following features： i） They involve the positive definiteness of the real part （as evaluated on ｜z｜ = 1） of the product of Г （z） and a matrix multiplier function of z. ii） For periodic A（k）, one class of multiplier functions can be chosen so as to impose no constraint on the rate of variations A（k）, but for aperiodic A（k）, which allows a more general multiplier function, constraints are imposed on certain global averages of the generalized eigenvalues of （A（k ＋ 1）,A（k））, k = 1, 2 iii） They are distinct from and less restrictive than recent results in the literature.     

Determination of water activities,osmotic and activity coefficients of the system NH4NO3–LiNO3–H2O at the temperature 298.15 K

The water activities of the mixed aqueous electrolyte {(y) NH₄NO₃+(1−y) LiNO₃)}(aq) are measured at total molalities from 0.2 mol kg⁻¹ to about saturation for different ionic-strength fractions $y$ of NH₄NO₃ with $y=0.20,0.50,0.80$. The results allow the deduction of osmotic coefficients. The experimental results are compared with the predictions of the Zdanovskii–Stokes–Robinson (ZSR), Robinson and Stokes (RS), Lietzke and Stoughton (LS II), Reilly–Wood–Robinson (RWR) mixing rules and the Pitzer model. From these measurements, the Pitzer mixing ionic parameters are determined and used to predict the solute activity coefficients in the mixture. The excess Gibbs energy is also determined.     

Thermodynamic reassessment of the Y 2O3–Al2O3–SiO2 system and its subsystems

Phase equilibria and thermodynamic properties at 1 bar in the Y ₂O₃–Al₂O₃–SiO₂ ternary system and its constituent binaries Y ₂O₃–Al₂O₃ and Y ₂O₃–SiO₂ have been reevaluated using the CALPHAD approach. The liquid phase is described by the ionic two-sublattice model with the formula (Al⁺³,Y ⁺³)_P(AlO₂⁻¹,O⁻²,SiO₄⁻⁴,SiO₂⁰)_Q. The SiO₂ solubility in the YAM phase was described using a compound energy model. Two datasets of self-consistent model parameters are presented. However, the rather meagre and scattered experimental data imply that the present assessments should be regarded as provisional. Some critical experiments are suggested for this system.     

Analytical Expansion and Numerical Approximation of the Fermi–Dirac Integrals F j(x) of Order j=−1/2 and j=1/2

This paper uses properties of the Weyl semiintegral and semiderivative, along with Oldham's representation of the Randles–Sevcik function from electrochemistry, to derive infinite series expansions for the Fermi–Dirac integrals _j (x), –j=–1/2, 1/2. The practical use of these expansions for the numerical approximation of _–1/2(x) and _1/2(x) over finite intervals is investigated and an extension of these results to the higher order cases j=3/2, 5/2, 7/2 is outlined.     

Analysis of kinematics/statics and workspace of a 2(SP+SPR+SPU) serial–parallel manipulator

The kinematics/statics and workspace of a 2(SP+SPR+SPU) serial–parallel manipulator are studied systematically. First, a 2(SP+SPR+SPU) manipulator including an upper and a lower SP+SPR+SPU parallel manipulators is constructed, and the inverse/forward displacements, velocity, acceleration and statics of the lower/upper parallel manipulators are studied, respectively. Second, the kinematics and statics of the lower/upper manipulators are combined and the displacement, velocity, acceleration, statics, and workspace of a 2(SP+SPR+SPU) manipulator are analyzed systematically. Third, the analytic solutions’ examples are given and verified by the simulation mechanism. This manipulator has some potential applications for the robot’s arm, leg, and twist, the serial–parallel machine tools, the sensor, the surgical manipulator, the tunnel borer, the barbette of warship, and the satellite surveillance platform.     

Liquid–liquid equilibrium of potassium/sodium carbonate + 2-propanol/ethanol + water aqueous two-phase systems and correlation at 298.15 K

Binodal data for 2-propanol + potassium/sodium carbonate + water systems and ethanol + sodium carbonate + water system were experimentally determined at 298.15 K, and the phase diagram was plotted. Three empirical equations were used to correlate binodal data. Base on the proposed equation with highest accuracy and lever rule, the phase equilibrium compositions for 2-propanol + potassium/sodium carbonate + water system were directly calculated by MATLAB. The Othmer–Tobias equation and the Bancroft equation were used to correlate tie-line data. The results indicate that the calculation method and corresponding tie-line data are reliable. The effect of salts on phase-separation was discussed. Salting-out coefficient and effective excluded volume of potassium carbonate and sodium carbonate in 2-propanol–water component solvent were calculated to evaluate the salting-out ability of salts. An effective excluded volume of sodium carbonate in ethanol/2-propanol–water component solvents was used to evaluate the phase-separation ability of investigated alcohols. Based on the experimental and calculated results, it can be concluded that sodium carbonate shows a higher salting-out ability than potassium carbonate and 2-propanol is easier to be excluded to the alcohol-rich phase than ethanol.     

Invariant analysis and conservation laws of (2+1) dimensional time-fractional ZK–BBM equation in gravity water waves

This paper intends to make an in-depth study on the symmetry properties and conservation laws of the ($2+1$) dimensional time fractional Zakharov–Kuznetsov–Benjamin–Bona–Mahony (ZK–BBM) equation with Riemann–Liouville fractional derivative. Symmetry properties have been investigated here via Lie symmetry analysis method. In view of Erdélyi-Kober fractional differential operator, the reduction of ($2+1$) dimensional time fractional ZK–BBM equation has been done into fractional ordinary differential equation. To analyse the conservation laws, new theorem of conservation law has been proposed here for constructing the new conserved vectors for ($2+1$) dimensional time fractional ZK–BBM equation with the help of formal Lagrangian.