DSC, TGA and dielectric properties of carboxymethyl cellulose/polyvinyl alcohol blends

Films with different compositions of polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC) blends have been prepared using the casting method. Differential scanning calorimetery (DSC), thermogravimetric analysis (TGA) and dielectric spectroscopy of all compositions have been investigated. It was found that PVA and CMC are compatible in the studied range of composition. With increasing CMC content, the thermal stability of PVA increases. Based on DSC and TGA data, the activation energies of all the investigated samples were calculated. The absorption edge (E_a) was also determined from Ultraviolet-visible (UV-vis) spectra.Dielectric permittivity, loss tangent and ac conductivity of all samples were studied as functions of temperature and frequency. The results show that the dielectric dispersion consists of both dipolar and interfacial polarization. The frequency dependence of the ac conductivity indicates that the correlated barrier hopping (CBH) is the most suitable mechanism for conduction. The polaron binding energy (U_M) was determined. Results of the present system are compared with those of similar materials.     

The Leray-Schauder condition for 1-set weakly-contractive and (ws)-compact operators

The main purpose of this article is to prove a collection of new fixed point theorems for (ws)-compact and so-called 1-set weakly contractive operators under Leray-Schauder boundary condition. We also introduce the concept of semi-closed operator at the origin and obtain a series of new fixed point theorems for such class of operators. As consequences, we get new fixed point existence for (ws)-compact (in particular nonexpansive) self mappings unbounded closed convex subset of Banach spaces. The main condition in our results is formulated in terms of axiomatic measures of weak noncompactness. Later on, we give an application to generalized Hammerstein type integral equations.     

恒压型抽水压缩空气储能系统的热力学及经济学多目标优化

为解决可再生能源存在的间歇性和波动性等问题,考虑到现有大规模储能技术的不足,提出了一种兼具抽水蓄能技术和压缩空气储能技术特点的恒压型抽水压缩空气储能系统.首先建立其热力学模型和经济学模型,然后以能量效率和单位能量成本作为目标函数,以水气比、预置压力、增压机压比和增压机效率作为决策变量,分别针对容量为1 MW、2MW、5 MW的系统进行多目标优化。多目标优化结果表明,当水气比约为7、预置压力约为4 MPa、增压机压比约为2、增压机效率较高时,系统具有较高的能量效率和较低的单位能量成本。同时,随着系统容量的增加,单位能量成本明显降低。研究结果可为该系统的工程应用提供理论支撑。     

NUMERICAL ANALYSIS AND SIMULATION OF RESOURCE‐EXPLORATION MODELS

ABSTRACT. In this paper, we examine models for exploration and consumption of resources. The fundamental feature of the models is the jump‐process nature of the exploration for and discovery of the resource. Several models have been proposed and analyzed in the literature. Here we provide numerical schemes, convergence properties, and some new models that provide risk‐averse policies to avoid depletion of the resource.     

铂沉积对Ga2O3-SiO2纳米粒子光催化性能的提高（英文）

Ga2O3‐SiO2 nanoparticles were prepared by a sol‐gel method and Pt was then immobilized on their surface via photo‐assisted deposition (PAD). The produced samples were characterized using X‐ray diffraction (XRD), ultraviolet and visible spectroscopy, photoluminescence emission spectroscopy, and surface area measurements. The catalytic performances of the Ga2O3‐SiO2 and Pt/ Ga2O3‐SiO2 samples were evaluated for the degradation of cyanide using visible light. XRD and EDX results showed that the Pt was well dispersed within the Ga2O3‐SiO2 phase and was detected on the surface of the catalyst, which confirmed the successful loading of Pt ions by the PAD method. BET results revealed that the surface area of Ga2O3‐SiO2 was higher than that of Pt/Ga2O3‐SiO2 . 0.3 wt% Pt/Ga2O3‐SiO2 exhibited the highest photocatalytic activity for degradation of cyanide under visible light. The catalyst could be reused with no loss in activity for the first 10 cycles.     

Optical properties of 1.3 μm room temperature emitting InAs quantum dots covered by In0.4Ga0.6As/GaAs hetero-capping layer

Room temperature 1.3 μm emitting InAs quantum dots (QDs) covered by an In_0.4Ga_0.6As/GaAs strain reducing layer (SRL) have been fabricated by solid source molecular beam epitaxy (SSMBE) using the Stranski–Krastanov growth mode. The sample used has been investigated by temperature and excitation power dependent photoluminescence (PL), photoluminescence excitation (PLE), and time resolved photoluminescence (TRPL) experiments. Three emission peaks are apparent in the low temperature PL spectrum. We have found, through PLE measurement, a single quantum dot ground state and the corresponding first excited state with relatively large energy spacing. This attribute has been confirmed by TRPL measurements which allow comparison of the dynamics of the ground state with that of the excited states. Optical transitions related to the InGaAs quantum well have been also identified. Over the whole temperature range, the PL intensity is found to exhibit an anomalous increase with increasing temperatures up to 100 K and then followed by a drop by three orders of magnitude. Carrier’s activation energy out of the quantum dots is found to be close to the energy difference between each two subsequent transition energies. PACS 68.65.Ac; 68.65.Hb; 78.67.Hc     

Lines of vortices for solutions of the Ginzburg–Landau equations

For disc domains and for periodic models, we construct solutions of the Ginzburg–Landau equations which verify in the limit of a large Ginzburg–Landau parameter specified qualitative properties: the limit density of the vortices concentrates on lines.     

含联萘基团的手性聚芳醚酮类环状齐聚物修饰电极的制备及其对色氨酸/磷钨杂多酸超分子化合物的手性识别

用溶剂诱导的含联萘基团的手性聚芳醚酮类环状齐聚物（S-PENEKC）制备修饰电极,利用循环伏安法实现了对D,L,DL-色氨酸／磷钨杂多酸的超分子化合物（D,L,DL—H,Trp2-[PW12O40]）的手性识别．     

主链含联萘的聚吡啶手性离子探针的合成和性质

合成了一种主链含联二萘基团的聚吡啶类共轭聚合物, 并通过圆二色谱(CD) 和紫外可见光谱(UV-Vis) 研究了其对Cu2+和Pd2+的识别能力, 并初步推测了识别机理.     

OPTIMIZATION APPROACH FOR THE MONGE-AMPèRE EQUATION

In this paper, we introduce and study a method for the numerical solution of the elliptic Monge-Ampère equation with Dirichlet boundary conditions. We formulate the Monge-Ampère equation as an optimization problem. The latter involves a Poisson Problem which is solved by the finite element Galerkin method and the minimum is computed by the conjugate gradient algorithm. We also present some numerical experiments.