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31.
32.
硼酸铝晶须的应用与制备 总被引:1,自引:0,他引:1
无机材料在国民经济和国防建设中均占有重要地位,其中硼酸铝晶须作为一种新型的无机应用材料,由于其具有许多的特殊功能,而且相对廉价,近年来受到了人们的广泛关注。就硼酸铝晶须的组成、物化性能及主要用途作了简单介绍,并主要介绍了生产硼酸铝晶须两种主要方法——助熔法和水热法。指出与发达国家相比,中国在这方面的研究工作还有很大差距,今后如能大力开展制备和应用方面的研究,中国的许多工程材料的性能将得到极大的提高。 相似文献
33.
风景园林实践在很大程度上受到政府决策的影响,以英国英格兰地区为例,劳动党政府于2008年提出的《儿童计划》和《游戏策略》,在为儿童游戏场地的更新和建设提供资金支持的同时,也间接推动了儿童场地设计导则与标准的发展。然而随着2010年政府换届,儿童户外游戏场地发展方案被移出了英国国家发展计划。将着重介绍在政策变化的背景下,于英格兰北部谢菲尔德市进行的名为“与自然共生”政府资助项目的实践经验,重点探究在政策引导的背景下,通过儿童户外游戏场地自然化改造的方式对社区户外空间进行适儿化提升的过程、方式和成果。将从多元参与协同工作的机制、儿童参与社区改造的方式以及儿童游戏场地的游戏价值提升等多个方面阐释该项目,为中国“十四五”规划背景下儿童友好型城市建设中社区环境优化提升面临的机遇与挑战提供基于英国经验的应对策略;对因地制宜地建设中国儿童友好城市及社区提供基于前沿实践的参考和建议。 相似文献
34.
Pai Peng Shenghui Guo Linhu Li Hui Jin Zhiwei Ge Liejin Guo 《International Journal of Hydrogen Energy》2021,46(53):26834-26847
In the offshore petroleum industry, polymer-containing oily sludge (PCOS) hinders oil extraction and causes tremendous hazards to the marine ecological environment. In this paper, an effective pretreatment method is proposed to break the adhesive structure of PCOS, and the experiments of supercritical water gasification are carried out under the influencing factors including residence time (5–30 min) and temperature (400–750 °C) in batch reactors. The increase of time and temperature all show great promoting effects on gas production. Polycyclic aromatic hydrocarbons, including naphthalene and phenanthrene, are considered as the main obstacles for a complete gasification. Carbon gasification efficiency (CE) reaches maximum of 95.82% at 750 °C, 23 MPa for 30 min, while naphthalene makes up 70% of the organic compounds in residual liquid products. The highest hydrogen yield of 19.79 (mol H2/kg of PCOS) is observed in 750 °C for 25 min. A simplified reaction pathway is presented to describe the gaseous products (H2, CO, CO2, CH4). Two intermediates are defined for describing the reaction process bases on the exhaustive study on organic matters in residual liquid products. The results show that the calculated data and the experimental data have a high degree of fit and tar formation reaction is finished within 10 min. 相似文献
35.
Ashish Nadar Atindra Mohan Banerjee M.R. Pai R.V. Pai Sher Singh Meena R. Tewari A.K. Tripathi 《International Journal of Hydrogen Energy》2018,43(1):37-52
Supported iron oxides have been established as an important class of catalyst for high temperature sulfuric acid decomposition. With an objective to elucidate the role of support in modifying the overall catalytic properties of dispersed iron oxide catalysts, a series of supported iron oxide based catalysts, Fe2O3 (15 wt%)/MO2 (M = Zr, Ce, Ti and Si), synthesized by adsorption-equilibrium method, is investigated for sulfuric acid decomposition reaction. The structure of dispersed iron oxide phases largely depended on the nature of the support oxide as revealed by the XRD and Mössbauer studies. α-Fe2O3 is found to be present as a major phase on ZrO2 and CeO2 support while ε-Fe2O3 was the major phase on silica supported iron oxide. On the other hand, presence of mixed oxide Fe2TiO5 was revealed over TiO2 support. Strong dispersed metal oxide-support interactions inhibited the total reduction of the dispersed phase on SiO2 and TiO2 as compared to complete reduction of dispersed iron oxide on CeO2 and ZrO2 supports during temperature programmed reduction upto 1000 °C. The order of catalytic activity at a temperature of ~750 °C is observed as Fe2O3/SiO2 > Fe2TiO5/TiO2 > Fe2O3/ZrO2 > Fe2O3/CeO2, while at higher temperatures of ~900 °C the SO2 yield is found to be comparable for all catalysts. A relationship between the rate of sulfate decomposition and catalytic activity is established through detailed TG-DTA investigations of sulfated catalyst and support. Considerable influence of the support oxide on the composition, structure, redox properties, morphology and catalytic activities of the active iron oxide dispersed phase has been observed. Thus, the support oxides operate as a critical component in the complex supported metal oxide catalysts and these findings might influence the design and development of future high temperature sulfuric acid decomposition catalysts. 相似文献
36.
Sushma A. Rawool Mrinal R. Pai A.M. Banerjee R.D. Bapat Chandrani Nayak A.K. Tripathi 《International Journal of Hydrogen Energy》2018,43(3):1271-1284
We have demonstrated earlier that maximum H2 generated @ 1.167 l/h/m2 over Cu0.02Ti0.98O2-δ photocatalyst with apparent quantum efficiency, AQE of 7.5% and solar fuel efficiency, SFE of 3.9% under sunlight. With an aim to scale-up the solar photocatalytic hydrogen process to pilot plant, optimization studies at lab scale as well as in upscaled photoreactors were performed over Cu0.02Ti0.98O2-δ, photocatalyst under UV/visible and sunlight. Cu0.02Ti0.98O2-δ was synthesized by facile sol-gel route and characterized by relevant techniques. Several operational parameters were investigated in order to finalize the conditions which are most favourable for photocatalytic hydrogen yield. Factors such as photocatalyst loadings, v/v concentration of sacrificial reagent, replacement of methanol by industrial waste glycerol, role of different configuration of light source with reactor, effect of stirring during the photocatalytic reaction, effect of fluctuations of solar flux at hourly basis, illumination area on hydrogen yield were studied. Contribution of each factor in determining the hydrogen yield was quantified. Relative standard deviation in hydrogen yield as a function of each factor was estimated. Our findings suggest that in addition to catalyst loadings and sacrificial reagent, improved dispersion of photocatalyst obtained by stirring the reaction mixture in horizontal geometry resulted in enhanced H2 yield. Hydrogen yield obtained at lab scale can be appropriately extrapolated with respect to illumination area instead of weight of photocatalyst. A relative standard deviation (RSD) of ± 3.82% and ± 4.53% in H2 yield was calculated for sunny and cloudy days in time zone of 10.30–16.30 h IST. Deviation of H2 yield was more on cloudy days and beyond 16:30 h. These studies have provided a daily window of 11:00–15:00 h to be utilized throughout the year for a commercial scaled up process, prohibiting the illumination during less productive hours of the day for shaping the improved economics of solar hydrogen generation. Our results obtained at lab scale would be useful to perform sunlight driven scaled –up photocatalytic process using low cost visible light efficient photocatalyst, Cu0.02Ti0.98O2-δ. 相似文献
37.
Yaqiang Ji Yuan Zhang Jiaqi Zhu Pai Geng Jonathan E. Halpert Liang Guo 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(24):2370173
Flexible pressure sensors play an indispensable role in flexible electronics. Microstructures on flexible electrodes have been proven to be effective in improving the sensitivity of pressure sensors. However, it remains a challenge to develop such microstructured flexible electrodes in a convenient way. Inspired by splashed particles from laser processing, herein, a method for customizing microstructured flexible electrodes by femtosecond laser-activated metal deposition is proposed. It takes advantage of the catalyzing particles scattered during femtosecond laser ablation and is particularly suitable for moldless, maskless, and low-cost fabrication of microstructured metal layers on polydimethylsiloxane (PDMS). Robust bonding at the PDMS/Cu interface is evidenced by the scotch tape test and the duration test over 10 000 bending cycles. Benefiting from the firm interface, the developed flexible capacitive pressure sensor with microstructured electrodes presents several conspicuous features, including a sensitivity (0.22 kPa−1) 73 times higher than the one using flat Cu electrodes, ultralow detection limit (<1 Pa), rapid response/recovery time (4.2/5.3 ms), and excellent stability. Moreover, the proposed method, inheriting the merits of laser direct writing, is capable of fabricating a pressure sensor array in a maskless manner for spatial pressure mapping. 相似文献
38.
39.
CY Pai TS Kuo TJ Jaw E Kurant CT Chen DA Bessarab A Salzberg YH Sun 《Canadian Metallurgical Quarterly》1998,12(3):435-446
The Extradenticle (Exd) protein in Drosophila acts as a cofactor to homeotic proteins. Its nuclear localization is regulated. We report the cloning of the Drosophila homothorax (hth) gene, a homolog of the mouse Meis1 proto-oncogene that has a homeobox related to that of exd. Comparison with Meis1 finds two regions of high homology: a novel MH domain and the homeodomain. In imaginal discs, hth expression coincides with nuclear Exd. hth and exd also have virtually identical, mutant clonal phenotypes in adults. These results suggest that hth and exd function in the same pathway. We show that hth acts upstream of exd and is required and sufficient for Exd protein nuclear localization. We also show that hth and exd are both negative regulators of eye development; their mutant clones caused ectopic eye formation. Targeted expression of hth, but not of exd, in the eye disc abolished eye development completely. We suggest that hth acts with exd to delimit the eye field and prevent inappropriate eye development. 相似文献
40.