Porous ZnCo2O4 nanowires synthesis via sacrificial templates: high-performance anode materials of Li-ion batteries

A simple microemulsion-based method has been developed to synthesize ZnCo(2)(C(2)O(4))(3) nanowires that can be transformed to porous ZnCo(2)O(4) nanowires under annealing conditions. The morphology of porous ZnCo(2)O(4) nanowires can be tuned by the initial ZnCo(2)(C(2)O(4))(3) nanowires and the annealing temperatures. The as-synthesized porous ZnCo(2)O(4) nanowires have been applied as anode materials of Li-ion batteries, which show superior capacity and cycling performance. The porous one-dimensional (1D) nanostructures and large surface area are responsible for the superior performance. Moreover, it is indicated that porous ZnCo(2)O(4) nanowires synthesized at low annealing temperature (500 °C) show larger capacity and better cycling performance than that prepared at high annealing temperature (700 °C), because of their higher porosity and larger surface area.     

电沉积CdSe薄膜的表面光伏研究

用电沉积法得到的CdSe薄膜, 在450 ℃热处理后, 其光电转换效率达到5.9％。 表面光伏谱测定结果表明, 电沉积CdSe薄膜经热处理后, 其光伏效应显著提高。推算出其少子扩散长度Lp等于0.42 μm。     

Effects of Annealing Temperature on Microstructure and Electrochemical Properties of Perovskite-type Oxide LaFeO3 as Negative Electrode for Metal Hydride/Nickel(MH/Ni) Batteries

We reported the effects of annealing temperatures on microstructure and electrochemical properties of perovskite-type oxide LaFeO₃ prepared by stearic acid combustion method. X-Ray diffraction(XRD) patterns show that the annealed LaFeO₃ powder has orthorhombic structure. Scanning electron microscopy(SEM) and transmission electron microscopy(TEM) images show the presence of homogeneously dispersed, less aggregated, and small crystals(30-40 nm) at annealing temperatures of 500 and 600℃. However, as the annealing temperature was increased to 700 and 800℃, the crystals began to combine with each other and grew into further larger crystals(90-100 nm). The electrochemical performance of the annealed oxides was measured at 60℃ using chronopotentiometry, poten-tiodynamic polarization, and cyclic voltammetry. As the annealing temperature increased, the discharge capacity and anti-corrosion ability of the oxide electrode first increased and then decreased, reaching the optimum values at 600℃, with a maximum discharge capacity of 563 mA·h/g. The better electrochemical performance of LaFeO₃ annealed at 600℃ could be ascribed to their smaller and more homogeneous crystals.     

Thermal actuation performance modification of coiled artificial muscle by controlling annealing stress

Twisted and coiled polymer (TCP) is a promising linear artificial muscle fabricated from nylon or other polymeric fibers, whose geometric structure is similar to a coil spring. TCP muscle is actuated reversibly with negative coefficients of thermal expansion. Twisting, coiling, and annealing are the main fabricating procedures. Annealing is the key process to form TCP muscles with stable performance. To modify and enhance actuation performance, it is necessary to explore and reveal influences of annealing process on thermal actuation (contraction strain, nominal modulus, and geometrical characteristic). Therefore, a new TCP fabrication and test platform is first established, which can quantize key geometrical and force parameters by multiple precise sensors. Then, four types of TCP muscles using nylon 6 fibers with varied diameters are fabricated and annealed under different conditions. As one of the important factors in annealing process, the nominal tensile stress is adjusted and controlled. Meanwhile, the contraction strain and nominal modulus are tested compared with the general annealing method. Finally, the experiment results show that contraction strain can be enhanced about two times (nominal modulus decreases accordingly) by increasing annealing stress, and the actuation performance can be remodeled reversibly by adjusting annealing stress and annealing repetitively. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 383–390     

Nanostructured AgPb(m)SbTe(m+2) system bulk materials with enhanced thermoelectric performance

Nanostructured Ag0.8Pbm+xSbTem+2 (m = 18, x = 4.5) system thermoelectric materials have been fabricated by combining mechanical alloying (MA) and spark plasma sintering (SPS) methods followed by annealing for several days to investigate the effect on microstructure and thermoelectric performance. It was found that appropriate annealing treatment could reduce both the electrical resistivity and the thermal conductivity at the same time, consequently greatly enhancing the thermoelectric performance. A low electrical resistivity of 2 x 10-3 Ohm-cm and low thermal conductivity of 0.89 W m-1 K-1 were obtained for the sample annealed for 30 days at 700 K. The very low thermal conductivity is supposed to be due to the nanoscopic Ag/Sb-rich regions embedded in the matrix. A high ZT value of 1.5 at 700 K has been achieved for the sample annealed for 30 days.     

Solvent Vapor Annealing Upgraded Orderly Intermolecular Stacking and Crystallinity to Enhance Memory Device Performance

Molecular stacking and crystallinity in a film can effectively affect the charge‐carrier mobility of semiconductor materials and corresponding device performance. Currently, solvent vapor annealing (SVA), as an effective thin‐film optimization strategy, which can select the appropriate solvent according to the characteristics of the molecular structure to optimize the intermolecular orderly arrangement, is often adopted. Thus, a small conjugated molecule C₂₀‐ID(TPCN)₂ with flexible alkyl side chains was synthesized and applied as active layer of sandwich memory devices. The active layer film has been annealed with different polar solvent vapors to evaluate the relationship among the molecular structure, solvent selection, annealing parameters and intermolecular stacking. Compared to un‐annealed devices, the memory devices based on the films through CH₂Cl₂‐annealing show better performance with a lower threshold voltage due to developed ordered molecular aggregation and better crystallinity, while a hydrophilic solvent vapor will weaken the device performance. This work not only reveals that selecting an appropriate solvent vapor for the molecular structure could be of vital importance in inducing the desired intermolecular stacking mode, but also provides a novel insight for the realization of organic semiconductor devices with excellent performance.     

Prediction of λmax of 1,4-naphthoquinone derivatives using ant colony optimization

Ant colony optimization (ACO) is a meta-heuristic algorithm, which is derived from the observation of real ants. In this paper, ACO algorithm is proposed to feature selection in quantitative structure property relationship (QSPR) modeling and to predict λ_max of 1,4-naphthoquinone derivatives. Feature selection is the most important step in classification and regression systems. The performance of the proposed algorithm (ACO) is compared with that of a stepwise regression, genetic algorithm and simulated annealing methods. The average absolute relative deviation in this QSPR study using ACO, stepwise regression, genetic algorithm and simulated annealing using multiple linear regression method for calibration and prediction sets were 5.0%, 3.4% and 6.8%, 6.1% and 5.1%, 8.6% and 6.0%, 5.7%, respectively. It has been demonstrated that the ACO is a useful tool for feature selection with nice performance.     

Investigation of the Effect of Thermal Annealing on Poly(3‐hexylthiophene) Nanofibers by Scanning Probe Microscopy: From Single‐Chain Conformation and Assembly Behavior to the Interfacial Interactions with Graphene Oxide

Poly(3‐hexylthiophene) (P3HT) has been widely used in devices owing to its excellent properties and structural features. However, devices based on pure P3HT have not exhibited high performance. Strategies, such as thermal annealing and surface doping, have been used to improve the electrical properties of P3HT. In this work, different from previous studies, the effect of thermal annealing on P3HT nanofibers are examined, ranging from the single polymer chain conformation to chain packing, and the interfacial interactions with graphene oxide (GO) at nanoscale dimensions, by using scanning tunneling microscopy (STM), atomic force microscopy (AFM) and Kelvin probe force microscopy (KPFM). High‐resolution STM images directly show the conformational changes of single polymer chains after thermal annealing. The morphology of P3HT nanofibers and the surface potential changes of the P3HT nanofibers and GO is further investigated by AFM and KPFM at the nanoscale, which demonstrate that the surface potentials of P3HT decrease, whereas that of GO increases after thermal annealing. All of the results demonstrate the stronger interfacial interactions between P3HT and GO occur after thermal treatments due to the changes in P3HT chain conformation and packing order.     

Ammonia‐Annealed TiO2 as a Negative Electrode Material in Li‐Ion Batteries: N Doping or Oxygen Deficiency?

Improving the chemical diffusion of Li ions in anatase TiO₂ is essential to enhance its rate capability as a negative electrode for Li‐ion batteries. Ammonia annealing has been used to improve the rate capability of Li₄Ti₅O₁₂. Similarly, ammonia annealing improves the Li‐ion storage performance of anatase TiO₂ in terms of the stability upon cycling and the C‐rate capability. In order to distinguish whether N doping or oxygen deficiencies, both introduced upon ammonia annealing, are more relevant for the observed improvement, a systematic electrochemical study was performed. The results suggest that the creation of oxygen vacancies upon ammonia annealing is the main reason for the improvement of the stability and C‐rate capability.     

Global optimization of Lennard-Jones clusters by a parallel fast annealing evolutionary algorithm

A parallel fast annealing evolutionary algorithm (PFAEA) was presented and applied to optimize Lennard-Jones (LJ) clusters. All the lowest known minima up to LJ(116) with both icosahedral and nonicosahedral structure, including the truncated octahedron of LJ(38), central fcc tetrahedron of LJ(98), the Marks' decahedron of LJ(75)(-)(77), and LJ(102)(-)(104), were located successfully by the unbiased algorithm. PFAEA is a parallel version of fast annealing evolutionary algorithm (FAEA) that combines the aspect of population in genetic algorithm and annealing algorithm with a very fast annealing schedule. A master-slave paradigm is used to parallelize FAEA to improve the efficiency. The performance of PFAEA is studied, and the scaling of execution time with the cluster size is approximately cubic, which is important for larger scale energy minimization systems.     

Control of all‐conjugated block copolymer crystallization via thermal and solvent annealing

Control of the crystallization of conjugated polymers is of critical importance to the performance of organic electronics, such as organic photovoltaic devices, due to the effect on charge separation and transport, particularly for all‐polymer devices. The block copolymer poly(3‐dodecylthiophene)‐block‐poly(9,9‐dioctylfluorene) (P3DDT‐b‐PF), which has matched crystallization temperatures for each block, is used to study the effects of processing history on resulting crystallization. For longer annealing times and rapid quenching to room temperature, P3DDT crystals are preferred whereas for shorter annealing times and slower quenching, PF crystals are preferred. Both crystal forms are evidenced for long annealing time and slow quenching. Additionally, for room temperature annealing in the presence of a chloroform vapor, PF crystals are found in the PF β phase with the predominant crystal peak oriented perpendicular to the thermally annealed case. These results will provide guidance for optimizing annealing strategies for future donor/acceptor block copolymer photovoltaic devices. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 900–906     

Synthesis of manganese oxide electrodes with interconnected nanowire structure as an anode material for rechargeable lithium ion batteries

Manganese oxide electrodes composed of interconnected nanowires are electrochemically synthesized in manganous acetate solution at room temperature without any template and catalyst. Annealing temperature affects the electrode morphology, crystallization, and electrochemical performance. Scanning electron microscope (SEM) results show that nanowires are uniformly distributed and sizes are about 12-18 nm in diameter; the diameter decreases to about 8-12 nm after annealing at 300 degrees C. X-ray diffraction (XRD) and transmission electron microscope (TEM) images indicate that nanowires have poor crystalline characteristics. The higher the annealing temperature, the higher the crystalline degree is in manganese oxide. The synthesized anode material shows a much larger capacity than the traditional graphite materials for lithium storage. After annealing at 300 degrees C, the electrode's reversible capacity reaches 800 mAhg(-1), and the specific capacity retention remains nearly constant after 100 cycles.     

Kalman filter quantitative resolution of shifted ESCA spectra after optimal alignment by simulated annealing

Summary The quantitative separation of overlapped responses accomplished by the Kalman filter algorithm is deteriorated by the errors in the model due to shifts of the component peaks. This is particularly true for spectral resolution in Electron Spectroscopy for Chemical Analysis (ESCA). A computational approach for the quantitative resolution of overlapping ESCA spectra when there is loss of collinearity between the pure component peaks and the mixture peak, has been developed. The procedure makes itera tive use of the Kalman filter for resolving the mixture spectrum with the component spectra aligned according to some values of the position parameters, and of the simulated annealing algorithm to find the optimal alignment. The performance of simulated annealing in pursuing this task, has been compared with those of simplex and steepest descent, by analyzing a set of overlapped synthetic spectra and some ESCA spectra of powder mixtures of lead compounds.     

Enhancing the thermal stability of polythiophene:fullerene solar cells by decreasing effective polymer regioregularity

Regioregularity has been shown to be an important aspect for the properties of poly(3-hexylthiophene) both in the pristine material and in bulk heterojunction photovoltaics with the fullerene derivative PCBM. Here we present a straightforward method to adjust the effective regioregularity of poly(3-hexylthiophene) by introducing 3,4-dihexylthiophene into the polymer chain. By investigating bulk heterojunction morphology and photovoltaic performance upon annealing, we observe that polythiophene with 91% regioregularity maintains equivalent electronic properties but forms a more thermally stable interpenetrating network with PCBM than polythiophene with regioregularity >96%.     

Influence of Temperature on Surface Morphology and Photoelectric Performance of CuAlO2 Thin Films

CuAlO₂ thin films were prepared on sapphire substrate by sol-gel method. The influences of annealing temperature, heating rates and annealing time on composition, morphology and photoelectric performance of film were investigated. The results of X-ray power diffraction, scanning electron microscope, transmissivity, and hall parameter tests showed that the CuAlO₂ phase was relatively pure when the annealing temperature was above 950 °C. The higher the temperature, the higher the peak position. Under the optimal conditions, CuAlO₂ film exhibited the best transmittance (90%) and the highest conductivity (1.23 S cm^?1). On this basis, increasing the heating rate and annealing time was in favor of enlarging the size of the particles and the film grain growth direction tended to be unified.     

Understanding and tuning of polymer surfaces for dialysis applications

Tailoring membrane properties for biomedical applications, e.g., hemodialysis, have been a challenge which material scientists have been addressing for last few decades. The fundamental challenge lies in identifying and controlling the parameters which are responsible for yielding cytocompatibility and hemocompatibility to the material. The present article is an attempt to understand the physical parameters which are responsible for the biological manifestations of a polymer membrane. Two types of dialysis membranes, viz., high performance membrane and high cutoff, have been synthesized. Membrane surfaces were modified via dry and wet annealing, and conditions of annealing were optimized. Subsequently, physical and surface properties of the membranes after annealing were investigated. In‐depth investigation of biological and blood response has been undertaken on the basis of fundamental parameters like polarizability and surface rigidity. Cell adhesion, proliferation, protein adsorption, hemolysis, platelet adhesion, thrombus formation, and complement activation tests were performed on the membranes. It was observed that dry heating increases surface smoothness but in the process develops cracks on membrane surface as well as increases work of adhesion for blood contact. On the other hand, wet heating of membrane surface not only improves biological performance but it is also easy to retrofit with existing spinning technologies for spinning dialysis membranes. In‐house spinning technology was used to synthesize hemodialysis membranes which were annealed at the optimized conditions, and their surfaces were compared with commercial fibers to ascertain the rationale of annealing as a facile method to lend desired surface properties to membranes. Copyright © 2016 John Wiley & Sons, Ltd.     

The photocatalytic performance for Mn-doping SrMoO4 reduced in H2/N2 mixture atmospheres

SrMoO₄ and Mn-doped SrMoO₄ nanoparticles have been synthesized by high temperature thermal decomposition of metal–organic salt in organic solvent with a high boiling point. Then they were reduced in H₂/N₂ mixture atmospheres at different reducing temperatures T_R. Samples were characterized by X-ray diffraction (XRD), UV–visible light spectrum (UV), and X-ray photoelectron spectroscopy (XPS). The XRD and XPS results showed that SrMoO₃ phase appears when the annealing temperature was 700 °C (SMO700). The light absorption edge shifted to the visible range and enhanced the visible light photocatalytic activity. The methyl blue (MB) solution was degraded, and the degradation efficiency was 80.30% in 120 min for SMO700 sample. For the 2%Mn doping SrMoO₄ sample, the efficiency of degradation reached 97.53% when the annealing temperature was 700 °C(2Mn-SMO700). The results showed that a certain amount of SrMoO₃ is helpful to improve the photocatalytic performance of SrMoO₄. In addition, the photocatalytic performance of SrMoO₄ was also related to Mn-doped amount, annealing temperature and annealing time in H₂/N₂ mixture atmospheres. The related mechanism was discussed.     

Influence of Mixed Imide Composition and Thermal Annealing on Ionic Liquid Uptake and Conductivity of Polyimide-Poly(ethylene glycol) Segmented Block Copolymer Membranes

Understanding the impact of different bridging groups in the two-step polymerization of poly(ethylene glycol) (PEG)-incorporated polyimide (PI) materials is significant. It is known that the proton exchange membranes (PEMs) used in industry today can experience performance degradation under rising temperature conditions. Many efforts have been devoted to overcoming this problem by improving the physical and mechanical properties that extend the hygrothermal life of a PEM. This work examines the effect of oxygenated and fluorinated bridging anhydrides in the production of PI-PEG PEMs. It is shown that the dianhydride identity and the amount incorporated in the synthesis influences the properties of the segmented block copolymer (SBC) membranes, such as increased ionic liquid uptake (ILU), enhanced conductivity and higher Young’s modulus favoring stiffness comparable to Nafion 115, an industrial standard. Investigations on the ionic conductivity of PI-PEG membranes were carried out to determine how thermal annealing would affect the material’s performance as an ion-exchange membrane. By applying a thermal annealing process at 60 °C for one hour, the conductivities of synthesized segmented block copolymer membranes values were increased. The effect of thermal annealing on the mechanical properties was also shown for the undoped SBC via measuring the change in the Young’s modulus. These higher ILU abilities and mechanical behavior changes are thought to arise from the interaction between PEG molecules and ethylammonium nitrate (EAN) ionic liquid (IL). In addition, higher interconnected routes provide a better ion-transfer environment within the membrane. It was found that the conductivity was increased by a factor of ten for undoped and a factor of two to seven for IL-doped membranes after thermal annealing.     

Co、Ni及其合金纳米线阵列的制备及磁性研究

采用交流电化学沉积法,在多孔阳极氧化铝(AAO）模板孔洞中成功组装了铁磁性金属Co、Ni、CoNi合金纳米线阵列并采用扫描电子显微镜(SEM）、X射线衍射(XRD）等对样品进行表征。结果表明,Co、Ni及CoNi合金阵列体系中纳米线均匀有序,形状各向异性较大(长径比达30以上）,有显著的结晶择优取向。对Co、Ni、CoNi合金纳米线阵列体系进行磁性分析,振动样品磁强计(VSM）测试结果显示,纳米线有明显的磁各向异性,适合用作垂直磁记录介质。纳米线阵列退火后沿纳米线方向矫顽力和矩形比减小,样品的垂直磁各向异     

Alignment of liquid crystals on solution-processed HfZnO films via ion beam irradiation

Liquid crystal (LC) alignment layers were prepared by fabricating solution-processed HfZnO films, annealing them, and treating them with ion beam (IB) irradiation, and the effect of annealing temperature upon the resulting film properties was studied. Homogeneous LC alignment was achieved on IB-irradiated HfZnO films. Topographical changes were observed from field-emission scanning electron microscopy as annealing temperature increased. X-ray photoelectron spectroscopy analysis showed that IB irradiation resulted in oxidation of HfZnO surfaces, which caused the LCs to be oriented more uniformly. The best electro-optical characteristics observed corresponded to the annealing temperature of 200°C. The low optimal annealing temperature for fabricating the HfZnO films suggested that this material has remarkable potential for LCD applications.