Modulation of electrical transport in calcium cobaltite ceramics and thick films through microstructure control and doping

Ca₃Co₄O₉ is a promising p-type thermoelectric oxide material having intrinsically low thermal conductivity. With low cost and opportunities for automatic large scale production, thick film technologies offer considerable potential for a new generation of micro-sized thermoelectric coolers or generators. Here, based on the chemical composition optimized by traditional solid state reaction for bulk samples, we present a viable approach to modulating the electrical transport properties of screen-printed calcium cobaltite thick films through control of the microstructural evolution by optimized heat-treatment. XRD and TEM analysis confirmed the formation of high-quality calcium cobaltite grains. By creating 2.0 at% cobalt deficiency in Ca_2.7Bi_0.3Co₄O_9+δ, the pressureless sintered ceramics reached the highest power factor of 98.0 μWm^?1 K^-2 at 823 K, through enhancement of electrical conductivity by reduction of poorly conducting secondary phases. Subsequently, textured thick films of Ca_2.7Bi_0.3Co_3.92O_9+δ were efficiently tailored by controlling the sintering temperature and holding time. Optimized Ca_2.7Bi_0.3Co_3.92O_9+δ thick films sintered at 1203 K for 8 h exhibited the maximum power factor of 55.5 μWm^?1 K^-2 at 673 K through microstructure control.     

A组分变化对AB2型储氢合金组织结构及电化学性能的影响

设计了两种成分AB2型合金,（Zr1-XTiX）（NiVMnCo）2＋α,采用XRD、SEM、TEM以及电化学性能测试方法分别对它们的铸态、快淬态及快淬态经过773 K、973 K和1 173 K退火处理的合金进行研究,结果表明,在AB2型储氢合金中加入少量Ti,可以增加电极的放电容量,提高循环寿命。熔体旋转快淬制备的非晶态合金电极的电化学性能差。快淬样品经过退火后,可获得纳米晶结构,能够大幅度提高电极材料的放电容量（370 mAh/g）和循环寿命（300次循环后容量衰减3%）。     

Controlling delivery and energy performance of parallel batch processors in dynamic mould manufacturing

Given the mounting concern about service levels and environmental sustainability, mould industry is facing growing pressure to improve delivery reliability and energy efficiency. While heat-treatment operation is a bottleneck that affects related performances in mould manufacturing. Effective production control of this operation is essential to improve the on-time delivery and reduce the energy consumption of the mould. The operation often involves parallel batch processors and incompatible jobs, which allows for simultaneous processing yet with same job family and different weights and due dates. This paper considers the batch process control of parallel processors for dealing with such non-identical jobs in dynamic environments. An event-driven look-ahead batching strategy called MLAB-DE has been proposed. In MLAB-DE, the individual decisions for each family excluding the effects of these decisions on other families are suggested firstly. Then each alternative decision by including its effects on all families is evaluated. MLAB-DE is used to control two kinds of conflicting objectives related to the delivery and energy performances and finally achieve trade-off based on two-level compromise programming model. Simulation study is conducted to verify the effectiveness of the MLAB-DE strategy and show that the results are promising as compared to benchmark rules.     

Effects of Deformation and Heat－treatment Process on Texture of Bi－2223／Ag Su perconducting Tapes

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净化煤焦油沥青的中间相热转化研究

本文用煤岩学方法研究离心法净化煤焦油沥青中间相的热转化过程,考察与评价了离心处理条件、原生与次生喹啉不溶物组成等对中间相热转化的影响。     

热处理对高压电解电容器阳极铝箔比电容的影响

本文研究了不同的退火工艺对450伏高压电解电容器用 L01铝箔(Al≮99.93%)组织结构和比电容的影响。结果表明,高温短时退火可以使铝箔的表面产生有利的取向,减少位错密度(ρ_⊥)的下降。L01铝箔加热到580℃保温40分钟后空冷,可获得最大的(100)织构百分数(f_((100))%=35.41),在退火条件下,f_((100))%是影响比电容(K)的重要因素,f_((100))%最大时,K 也最大(K=0.28μF/cm~2)。随着退火温度和退火时间的增加,晶粒尺寸长大,位错密度下降,只有晶粒大小适宜,ρ_⊥下降不多,f_((100))%大大增加时,才可获得高的 k 值。     

Preparation of Pt/NiO-C electrocatalyst and heat-treatment effect on its electrocatalytic performance for methanol oxidation

Pt catalyst supported on Vulcan XC-72R containing 5 wt% NiO (Pt/NiO–C) showed larger electrochemical active surface area and higher electrochemical activity for methanol oxidation than Pt catalyst supported on Vulcan XC-72R using polyol method without NiO addition. Prepared Pt/NiO–C electrocatalyst was heat-treated at four temperatures (200, 400, 600, and 800 °C) in flowing N₂. X-ray diffraction and temperature-programmed desorption results indicated that NiO was reduced to Ni in inert N₂ during heat-treatments at temperatures above or equal to 400 °C, while oxygen from NiO reacted with carbon support due to the catalytic effect of Pt. The reduced Ni formed an alloy with Pt, which, according to the X-ray photoelectron spectroscopy data, resulted in a shift to a lower binding energy of Pt 4f electrons. The Pt/NiO–C electrocatalyst heat-treated at 400 °C showed the best activity in methanol oxidation due to the change in Pt electronic structure by Ni and the minimal aggregation of Pt particles.     

纳米级炭黑在不同热处理温度下的结构研究

在惰性气氛保护下,对炭黑样品进行不同温度下的热处理,得到具有不同石墨化度的炭黑样品。通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、热重分析仪(TG)、以及拉曼分析仪(Raman)等对其进行了结构表征,结果表明随着碳化温度的升高,炭黑样品的石墨化程度显著增大,尤其在经过2 800℃高温热处理的炭黑样品中出现了中空的石墨化结构,有望成为具有较大吸附性能的橡塑弹性体材料的较好补强剂。     

Characterization of rubrene polycrystalline thin film transistors fabricated using various heat-treatment conditions

We observed the crystal structure changes of rubrene (5,6,11,12-tetraphenylnaphthacene) polycrystal thin films on SiO₂/Si(100) substrates at various heat-treatment temperatures by X-ray diffraction, and a near-field microwave microprobe technique. An amorphous rubrene thin film was initially observed at heat-treatment temperature of 35 °C. After the treatment with in-situ vacuum post-annealing at 80 °C for 22 h, the rubrene thin film was transformed from the amorphous phase into a crystalline phase of orthorhombic structure. We could obtain a higher field effect mobility of 0.047 cm²/V·s and lower threshold voltage of − 4 V for the following heat-treatment process: pre-annealing at 80 °C, cooling at 40 °C, and post-annealing at 80 °C for 22 h.     

WC—Co硬质合金热处理强化机理作用的研究

本文探讨了WC-15wt%Co硬质合金的力学性能与热处理工艺的关系。并以X射线衍射和透射电子显微镜为主要手段,研究了合金在烧结后的冷却或淬火中粘结相由面心立方β—Co→密排六方α-Co转变的马氏体相变过程。分析了热处理前后WC硬质相的表层宏观应力及其对合金性能的影响。比较了合金在热处理态和常规烧结态下显微结构的差异。结果表明,粘结相面心立方β-Co含量的升高;WC相表层宏观压应力的增加以及WC晶粒间邻接度的减少是该合金热处理的主要强化机理。