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%）。     

一效蒸发器主要制作工艺

介绍了一效蒸发器的主要制作工艺,将设备的整体热处理改为局部热处理和胀紧率的确定,为强度胀接大口径管子积累了经验。     

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

ＥｆｆｅｃｔｓｏｆＤｅｆｏｒｍａｔｉｏｎａｎｄＨｅａｔ－ｔｒｅａｔｍｅｎｔＰｒｏｃｅｓｓｏｎＴｅｘｔｕｒｅｏｆＢｉ－２２２３／ＡｇＳｕｐｅｒｃｏｎｄｕｃｔｉｎｇＴａｐｅｓＧｕｏＸｕ；ＷａｎｇＣｈａｏｑｕｎａｎｄＹｕａｎＧｕａｎｓｅｎ（郭旭）（王超群）...     

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。     

Heat-treatment of isomorphously substituted ZSM-5 (MFI) zeolites An ESR and Mössbauer spectroscopy and kinetic study

Fe-ZSM-5 zeolites comprise of three types (I, II and III) of iron (Fe³⁺) sites in both as synthesized (AS) and heat-treated states. Previous evidence could be confirmed by the assignment of ESR lines, registered in the X-band, stating: (i) type I framework Fe³⁺ sites (in T_h oxygen coordination), where charge compensation occurs mainly by Na⁺ ions and the crystal field (cf) approximates cubic symmetry, produce resonances at near to g = 2.00; (ii) type II and probably type III binuclear Fe...Fe dioxo- and oxo-bridges manifest themselves in producing slightly distorted surroundings of axial symmetry, and the relevant powder-averaged subspectrum is superimposed on the previous one in the g  2.45–1.98 interval. As the temperature of the heat-treatment (HT) is raised, type II and III sites will be annihilated with preference, under concomitant production of amorphous Fe₂O₃ possessing molecular dispersity. (iii) The weak ESR signal (2–4%) at g  4.27 is attributed to T_h coordinated framework sites in the surface layers (≈ 1 u.c. thick) under the influence of solid surface tension, giving rise to fully rhombic cf symmetry.

The size of the ejected Fe₂O₃ particles, as estimated from Mössbauer spectra (no hyperfine structure at 77 K) is less than 2.9 nm. The extremely large electron affinity of Fe³⁺ ions manifests itself in decreased ionicity (and unexpectedly dominant cubic symmetry), activity in biomimetic oxidations, autoreduction and spontaneous reoxidation etc.

In the liquid phase oxidation by hydrogen peroxide of n-hexane and cyclohexane the heat-treated Ti-ZSM-5 samples exhibited both activity- and selectivity dependence on HT. On the basis of experiences drawn from the heat-treatments proposal is made for the structures of the defect site (producing the 960 cm⁻¹ IR signal) and the active centre of selective oxidation. The proposal seems to be in accord with the experimental observations (isotopic exchange, MAS-NMR behaviour etc.) published so far.     

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。