Grain growth kinetics and growth mechanism of columnar Al2O3 crystals in xNb2O5–7.5La2O3-Al2O3 ceramic composites

xNb₂O₅–7.5La₂O₃-Al₂O₃ ceramic composites with in-situ-grown columnar Al₂O₃ crystals were successfully prepared by microwave sintering at 1450–1525?°C using α-Al₂O₃, Nb₂O₅, and La₂O₃ powders as raw materials. X-ray diffraction results indicated that the main phases were Al₂O₃, LaNbO₄, and Nb₂O₅ in the prepared samples. A field emission scanning electron microscope (FESEM) showed that the Al₂O₃ crystals appeared as columnar in the structure. Moreover, the grain size of the columnar Al₂O₃ crystals increased with the Nb₂O₅ content. The ratio of the major axis to the minor axis of the crystals was largest when the Nb₂O₅ content was 15?vol%. Furthermore, the grain-growth kinetics index (n), growth activation energy (Q), and growth mechanism of the columnar Al₂O₃ crystals were studied. The results indicated that the Nb₂O₅ addition could promote formation and growth of columnar Al₂O₃ crystals, and the grain-growth activation energy indicated that the dissolution process controls the crystal growth. The growth mechanism of the columnar Al₂O₃ crystals was also studied. The present work demonstrated that Nb₂O₅ is a good additive for the preparation of Nb₂O₅–7.5La₂O₃-Al₂O₃ composite ceramics with columnar Al₂O₃ crystals.     

煤破碎过程中CO产生量变化规律实验研究

为研究煤破碎过程中比表面积变化与CO产生量之间的影响规律,采用实验研究的方法,现场采集凌志达矿15号煤新鲜煤样,分别在氮气和空气环境下破碎,测定不同粒径的煤样的比表面积,结合气相色谱仪定量分析数据,分析煤样比表面积与CO产生量之间的关系,最后利用Matlab软件对空气环境下煤样比表面积与CO产生量曲线进行拟合,得到了拟合公式和拟合曲线.     

Real-time characterization of aerosol particle composition,sources and influences of increased ventilation and humidity in an office

Most of human exposure to atmospheric pollutants occurs indoors, and the components of outdoor aerosols may have been changed in the way before reaching indoor spaces. Here we conducted real-time online measurements of mass concentrations and chemical composition of black carbon and the non-refractory species in PM_2.5 in an occupied office for approximately one month. The open-close windows and controlled dampness experiments were also performed. Our results show that indoor aerosol species primarily originate from outdoors with indoor/outdoor ratio of these species typically less than unity except for certain organic aerosol (OA) factors. All aerosol species went through filtration upon transport indoors. Ammonium nitrate and fossil fuel OA underwent evaporation or particle-to-gas partitioning, while less oxidized secondary OA (SOA) underwent secondary formation and cooking OA might have indoor sources. With higher particulate matter (PM) mass concentration outdoors than in the office, elevated natural ventilation increased PM exposure indoors and this increased exposure was prolonged when outdoor PM was scavenged. We found that increasing humidity in the office led to higher indoor PM mass concentration particularly more oxidized SOA. Overall, our results highlight that indoor exposure of occupants is substantially different from outdoor in terms of mass concentrations and chemical species.     

基于非接触式技术的工业点胶机计量测定装置研究

采用高精度的非接触式激光法设计了可对点胶机进行现场计量的检测装置;按照GB/T 26799—2011标准,采用非接触式激光法和传统法对点胶机的重复性、移动速度准确度等进行了对比试验,并用传递比较试验法验证了非接触式激光法的计量规范性。研究结果表明:非接触式激光法测得点胶机的重复性、移动速度准确度均优于传统法,传递比较试验中测得的有效行程和速率均满足工业点胶机的计量规范要求。     

Lessons learned from studying public initiatives to support energy efficiency finance in Thailand from 1992 to 2014

Despite the huge technical and market potential for cost-effective energy efficiency investments in Southeast Asian markets, only a small fraction of this potential has been realised. Given that the major share of global future energy demand, and associated greenhouse gas emissions, will come from emerging economies, it is important to understand the barriers to mainstreaming energy efficiency into the financial sector. This paper focuses on public initiatives that support one of the main barriers: access to capital. The researchers chose Thailand as a case study because of the range of energy efficiency finance programmes that have been designed and implemented since the early 1990s. Interviews with 21 experts from government, the private sector and academia provided the core data for this research. The analysis employed a multi-level perspective and focused on the historical evolution of public support of energy efficiency finance in the country. We identified three distinct phases of public policy development over the past two decades. Despite an impressive variety of ambitious and creative programmes, the initiatives have not yet succeeded in integrating energy efficiency into the financial sector in a meaningful way. Some of the key lessons found are that (a) it is better to treat energy efficiency and renewable energy in separate financing initiatives, (b) governments find it challenging to design effective mechanisms to de-risk financial investments, and (c) international organisations play an important role in testing and facilitating the introduction of new financing approaches and mechanisms. In emerging economies, cost-effective implementation of energy efficiency measures is a promising alternative that can reduce the need for investment in large-scale power generation capacity. The researchers hope that this paper will contribute to more effective design of programmes to incentivise energy efficiency financing in Thailand and in other economies in Southeast Asia.