Synthesis and characterization of polymer electrolytes based on cross‐linked phenoxy‐containing polyphosphazenes

A new method to prepare the polymer electrolytes for lithium‐ion batteries is proposed. The polymer electrolytes were prepared by reacting poly(phosphazene)s (MEEPP) having 2‐(2‐methoxyethoxy)ethoxy and 2‐(phenoxy)ethoxy units with 2,4,6‐tris[bis(methoxymethyl)amino]‐1,3,5‐triazine (CYMEL) as a cross‐linking agent. This method is simple and reliable for controlling the cross‐linking extent, thereby providing a straightforward way to produce a flexible polymer electrolyte membrane. The 6 mol % cross‐linked polymer electrolyte (ethylene oxide unit (EO)/Li = 24:1) exhibited a maximum ionic conductivity of 5.36 × 10^?5 S cm^?1 at 100 °C. The ⁷Li linewidths of solid‐state static NMR showed that the ionic conductivity was strongly related to polymer segment motion. Moreover, the electrochemical stability of the MEEPP polymer electrolytes increased with an increasing extent of cross‐linking, the highest oxidation voltage of which reached as high as 7.0 V. Moreover, phenoxy‐containing polyphosphazenes are very useful model polymers to study the relationship between the polymer flexibility; that is, the cross‐linking extent and the mobility of metal ions. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 352–358     

Static snapping load of a hinged extensible elastica

In this paper we discuss the static snapping load of a hinged buckled beam subject to a midpoint force. Three different models are compared; they are small-deformation theory, inextensible elastica, and extensible elastica. As expected, small-deformation theory fails to predict the static snapping load accurately in the large-deformation range. In the small-deformation range, on the other hand, inextensible elastica model predicts the static snapping load poorly. Finally, by allowing the elastica to be extensible, it is observed that one can predict the static snapping load accurately both in the small- and large-deformation ranges.     

Simultaneously All-Optical Inverted and Noninverted Wavelength Conversion Employing Ultra-Small Silicon-on-Insulator Waveguide

We propose single-to-dual all-optical wavelength conversion based on stimulated Raman effect on silicon waveguides. Simulation results of non-return-to-zero (NRZ) pseudorandom bit sequence (2⁷–1 code) at 10, 50, and 200-Gbit/s rates of conversion in an ultra-small silicon-on-insulator waveguide are presented. The main goal in the proposed scheme is that the converted signal can be obtained simultaneously inverted, at the 1550 nm channel (down-conversion) and non-inverted, at the 1846 nm channel (up-conversion), for original signal fixed at 1686 nm.     

Rapid analysis of abused drugs using nanostructured silicon surface assisted laser desorption/ionization mass spectrometry

This study developed a rapid, sensitive, and matrix-free method for the determination of amphetamine (AMP), methamphetamine (MA), codeine (COD), morphine (MOR), and ketamine (KET) using nanostructured silicon surface assisted laser desorption/ionization mass spectrometry (nSi-MS). The nanostructured silicon (nSi) chip used in this study was created by employing the metal-assisted etching process. Drug standard tests were applied to the nSi chip platform to evaluate the nSi-MS performance, including detection sensitivity, limit of detection, linearity, and repeatability. Real urine samples obtained from drug addict detainees were directly applied to the nSi chip for drug analysis. By observing the nSi-MS spectra, the target drug peaks can be identified; and an antibody pull-down assay was performed to confirm the specificity of the detected targets. nSi-MS drug quantification was assayed, yielding comparable results with those from using the GC-MS approach. The advantages of applying nSi-MS to analyze AMP, MA, COD, MOR, and KET in the urine of addicts are simple, extremely small urine volumes (～10 μL), and a fast analysis procedure (<15 minutes).     

Drops sitting on a tilted plate: receding and advancing pinning

The wetting behavior of a liquid drop sitting on an inclined plane is investigated experimentally and theoretically. Using Surface Evolver, the numerical simulations are performed based on the liquid-induced defect model, in which only two thermodynamic parameters (solid-liquid interfacial tensions before and after wetting) are required. A drop with contact angle (CA) equal to θ is first placed on a horizontal plate, and then the plate is tilted. Two cases are studied: (i) θ is adjusted to the advancing CA (θ(a)) before tilting, and (ii) θ is adjusted to the receding CA (θ(r)) before tilting. In the first case, the uphill CA declines and the downhill CA remains unchanged upon inclination. When the tilted drop stays at rest, the pinning of the receding part of the contact line (receding pinning) and the depinning of the advancing part of the contact line (advancing depinning) are observed. The free energy analysis reveals that upon inclination, the reduction of the solid-liquid free energy dominates over the increment of the liquid-gas free energy associated with shape deformation. In the second case, the downhill CA grows and the uphill CA remains the same upon inclination. Advancing pinning and receding depinning are noted for the tilted drop at rest. The free energy analysis indicates that upon inclination, the decrease of the liquid-gas free energy compensates the increment of the solid-liquid free energy. The experimental results are in good agreement with those of simulations.     

Economic order quantity under advance payment

Though advance payment is widely used in practice, its influences on buyer’s inventory policy are rarely discussed. This paper investigates the buyer’s inventory policy under advance payment, including all payment in advance and partial-advanced–partial-delayed payment. The buyer’s ordering policy is derived by minimizing his total inventory costs including inventory holding cost, ordering cost, and interest cost caused by advance payment or delayed payment. The conclusions show that when all the payment is paid in advance, the buyer’s optimal replenishment cycle is influenced only by the price discount associated with advance payment, and the length of advance payment has no effect. For the partial-advanced–partial-delayed payment case, the buyer’s replenishment cycle is also not influenced by the length of advance period. However, in this situation, the delayed period and the price discount may have impacts on the inventory policy. We also use discounted cash flow (DCF) model to derive the buyer’s replenishment cycle and show that the replenishment cycle is negatively related to the length of advance period. Numerical examples are presented to illustrate the results.     

Nucleophilic Solvent Participation in the Solvolysis of Tertiary Bromoalkanes

The solvolysis of 2‐bromo‐2‐methylpropane ( 1B ), 2‐bromo‐2‐methylbutane ( 2B ), 2‐bromo‐2, 3‐di‐methylbutane ( 3B ), 2‐bromo‐2, 3, 3‐trimethylbutane ( 4B ), 3‐bromo‐3‐methylpentane ( 5B ), 3‐bromo‐2, 3‐dimethylpentane ( 6B ), 3‐bromo‐2, 2, 3‐trimethylpentane ( 7B ), 3‐bromo‐3‐ethylpentane ( 8B ), 3‐bromo‐3‐ethyl‐2‐methylpentane ( 9B ) and 2‐bromo‐2, 4, 4‐trimethylpentane ( 11B ) in 15 to 21 solvents was studied, and correlation analyses by using the single‐ and dual‐parameter Grunwald‐Winstein equations (Eqns 1 and 2) were examined. Substrates 7B, 9B and 11B showed excellent linear relationship (R ≥ 0.997) in the logk ‐ Y_Br plots and indicated limiting S_N1 mechanism for the solvolysis. On the other hand, bromides 1B‐6B and 8B gave linear correlations (R = 0.987–0.996) with the dual‐parameter (Y_Br and N_OTs) equation (2) only, which indicated the presence of significant nucleophilic solvent participation. Normal trends of reactivity due to the relief of B‐strain could be found in the poorly nucleophilic trifluoroethanol. Similar to the corresponding chlorides, the overwhelming influence of nucleophilic solvent assistance results in the observed inverse order of reactivity: k( 2B ) > k( 3B ), k( 5B ) > k( 6B ) and k( 8B ) > k( 9B ).     

A continuous approximation approach for the integrated facility-inventory allocation problem

In today’s retail business many companies have a complex distribution network with several national and regional distribution centers. This article studies an integrated facility location and inventory allocation problem for designing a distribution network with multiple distribution centers and retailers. The key decisions are where to locate the regional distribution centers (RDCs), how to assign retail stores to RDCs and what should be the inventory policy at the different locations such that the total network cost is minimized. Due to the complexity of the problem, a continuous approximation (CA) model is used to represent the network. Nonlinear programming techniques are developed to solve the optimization problems. The main contribution of this work lies in developing a new CA modeling technique when the discrete data cannot be modeled by a continuous function and applying this technique to solve an integrated facility location-allocation and inventory-management problem. Our methodology is illustrated with the network from a leading US retailer. Numerical analysis suggests that the total cost is significantly lower in the case of the integrated model as compared with the non-integrated model, where the location-allocation and inventory-management problems are considered separately. This paper also studies the effects of changing parameter values on the optimal solutions and to point out some management implications.     

Photocatalytic TiO2 thin films deposited on flexible substrates by radio frequency (RF) reactive magnetron sputtering

Titanium dioxide (TiO₂) thin films were deposited on flexible polycarbonate (PC) substrates by radio frequency (RF) reactive magnetron sputtering. The target was metallic titanium, argon was the plasma gas and oxygen was the reactive gas. Taguchi’s method, which uses an L₉ (3⁴) orthogonal array, signal-to-noise ratio and analysis of variance (ANOVA), was employed to study the performance of the deposition process. The effects of the deposition parameters on the structure, morphology and photocatalytic performance of the TiO₂ films were analyzed using scanning electron microscopy (SEM), X-ray diffraction, and UV-vis-NIR spectroscopy. Experiments varied RF power (50, 100, 150 W), deposition time (2, 3, 4 h), O₂/(Ar + O₂) argon/oxygen ratios (40, 60, 80%) and substrate temperatures (room, 80, 120 °C), to optimize the photoinduced decomposition of methylene blue (MB). The experimental results illustrate the effectiveness of this approach.     

Ionothermal synthesis of metal oxalatophosphonates with a three-dimensional framework structure: Na2M3(C2O4)3(CH3PO3H)2 (M = FeII and MnII)

Two isostructural transition-metal oxalatophosphonates, Na2M3(C2O4)3(CH3PO3H)2 (M = Fe(II) and Mn(II)), have been synthesized by using a low-melting-point eutectic mixture of choline chloride and malonic acid as a solvent and characterized by single-crystal X-ray diffraction and 57Fe M?ssbauer spectroscopy. The 3D framework structure consists of a corner-sharing octahedral trimer that is linked with other trimers through two distinct oxalate ligands with unusual linkage types, phosphonate tetrahedra, and H bonds to form infinite channels along the [101] direction where the Na+ cations are located. They are the first examples for the use of an ionic liquid as a solvent in the synthesis of metal oxalatophosphonates. Crystal data for the Fe compound follow: monoclinic, P2(1)/n (No. 14), a = 5.8063(1) A, b = 10.3867(3) A, c = 14.8094(4) A, beta = 96.926(1) degrees , and Z = 2. Crystal data for the Mn compound are the same as those for the Fe compound except a = 5.8734(9) A, b = 10.557(2) A, c = 14.863(2) A, and beta = 96.691(2) degrees .