低碳钢中磷的偏聚与再结晶织构

本文用正、倒极图和ODF法研究了低碳钢板在不同冷轧和再结晶退火条件下,磷对再结晶织构的影响。用金相术、扫描电镜和电子探针研究了磷在钢中的分布和显微组织。结果发现,磷促进了与轧向平行的一组〈001〉和与轧面法向平行的一组〈111〉纤维织构的生成;这种作用与预退火温度密切相关,在390和590℃进行预退火就呈现,在490℃就抑制。在促进织构生成的预退火温度时产生晶内磷偏聚的异常显微组织。并认为这种纤维织构的形成与晶内磷偏聚有关。     

A high propylene productivity over B2O3/SiO2@honeycomb cordierite catalyst for oxidative dehydrogenation of propane

Boron-based metal-free catalysts for oxidative dehydrogenation of propane (ODHP) have drawn great attention in both academia and industry due to their impressive activity and olefin selectivity. Herein, the SiO₂ and B₂O₃ sequentially coated honeycomb cordierite catalyst is designed by a two-step wash-coat method with different B₂O₃ loadings (0.1%-10%) and calcination temperatures (600, 700, 800 ℃). SiO₂ obtained by TEOS hydrolysis acts as a media layer to bridge the cordierite substrate and boron oxide via abundant Si-OH groups. The welldeveloped straight channels of honeycomb cordierite make it possible to carry out the reactor under high gas hourly space velocity (GHSV) and the thin wash-coated B₂O₃ layer can effectively facilitate the pore diffusion on the catalyst. The prepared B₂O₃/SiO₂@HC monolithic catalyst exhibits good catalytic performance at low boron oxide loading and achieves excellent propylene selectivity (86.0%), olefin selectivity (97.6%, propylene and ethylene) and negligible CO₂ (0.1%) at 16.9% propane conversion under high GHSV of 345,600 ml·(g B₂O₃)^-1·h^-1, leading to a high propylene space time yield of 15.7 g C₃H₆·(g B₂O₃)^-1·h^-1 by suppressing the overoxidation. The obtained results strongly indicate that the boron-based monolithic catalyst can be properly fabricated to warrant the high activity and high throughput with its high gas/surface ratio and straight channels.     

A high propylene productivity over B2O3/SiO2@honeycomb cordierite catalyst for oxidative dehydrogenation of propane

Boron-based metal-free catalysts for oxidative dehydrogenation of propane (ODHP) have drawn great attention in both academia and industry due to their impressive activity and olefin selectivity. Herein, the SiO₂ and B₂O₃ sequentially coated honeycomb cordierite catalyst is designed by a two-step wash-coat method with different B₂O₃ loadings (0.1%–10%) and calcination temperatures (600, 700, 800 °C). SiO₂ obtained by TEOS hydrolysis acts as a media layer to bridge the cordierite substrate and boron oxide via abundant SiOH groups. The well-developed straight channels of honeycomb cordierite make it possible to carry out the reactor under high gas hourly space velocity (GHSV) and the thin wash-coated B₂O₃ layer can effectively facilitate the pore diffusion on the catalyst. The prepared B₂O₃/SiO₂@HC monolithic catalyst exhibits good catalytic performance at low boron oxide loading and achieves excellent propylene selectivity (86.0%), olefin selectivity (97.6%, propylene and ethylene) and negligible CO₂ (0.1%) at 16.9% propane conversion under high GHSV of 345,600 ml·(g B₂O₃)⁻¹·h⁻¹, leading to a high propylene space time yield of 15.7 g C₃H₆·(g B₂O₃)⁻¹·h⁻¹ by suppressing the overoxidation. The obtained results strongly indicate that the boron-based monolithic catalyst can be properly fabricated to warrant the high activity and high throughput with its high gas/surface ratio and straight channels.     

回族聚居地区思想政治教育的地位和价值探讨

阐述了思想政治教育的社会结构性地位和社会功能性地位。联系我国回族聚居地区的实际,分析了在回族聚居地区加强思想政治教育的意义。     

非晶态Fe_（80）B_（20）合金晶化产物研究

利用Ｘ射线衍射及透射电子显微镜等手段研究了非晶态Ｆｅ_（８０）Ｂ_（２０）合金的晶化产物结构与热处理温度的关系，发现在不同退火温度下晶化产物均由α－Ｆｅ（Ｂ）固溶体和Ｆｅ－Ｂ化合物组成；α－Ｆｅ（Ｂ）固溶体的相对含量随退火温度的升高而增多；化合物有Ｆｅ_３Ｂ和Ｆｅ_（３．５）Ｂ两种，它们的相对含量与退火温度密切相关且表现出不同程度的晶格畸变．     

蒸发法制备Ni－Ti纳米非晶合金粒子

采用气相蒸发法制备纳米量级的Ｎｉ－Ｔｉ非晶合金粒子，研究了各种因素对Ｎｉ－Ｔｉ纳米非晶合金粒子形成的影响，并用透射电子显微镜，高分辨电子显微镜，Ｘ射线衍射仪和能谱等多种手段对纳米非晶合金粒子进行了表征．结果表明，当粒子成分在共晶区Ｎｉ（４０）Ｔｉ（６０）附近时，容易形成非晶；较低惰性气体压力和较高蒸发温度有利于Ｎｉ－Ｔｉ纳米非晶粒子的形成．     

聚苯胺与丙烯酸树脂共混研究及复合导电膜的制备

采用溶液聚合法制备了掺杂态聚苯胺(PANI)的二甲苯溶液,研究了掺杂态PANI与几种丙烯酸树脂共混体系的导电性能.并分别以丙烯酸树脂和掺杂态PANI/丙烯酸树脂为成膜基质,添加导电填料,制备出复合导电涂膜.探讨了PANI的加入对导电性能的影响,并采用SEM手段,分析了涂膜表面微观形貌的变化.     

南五味子超声波提取物清除自由基活性的研究

以南五味子为原料,探讨5种有机溶剂提取物清除DPPH·、·OH的活性,并以无水乙醇为溶剂,比较超声波提取物和溶剂浸提物对自由基的清除效果。通过正交试验优化超声波提取条件,结果表明,南五味子不同溶剂提取物对DPPH·的清除效果依次为乙醇>丙酮>氯仿>石油醚>乙酸乙酯,无水乙醇提取物对DPPH·的清除率达94.24%。对·OH的清除效果依次为氯仿>石油醚>乙酸乙酯>丙酮>乙醇,氯仿提取物对·OH的清除率达80.96%。以无水乙醇为溶剂,超声波提取物对DPPH·和·OH的清除率比浸提物分别提高了24.66%和12.95%。当原料-乙醇比例为1∶20(g/mL)时,超声波优化提取条件是:超声频率75 kHz,温度75℃,提取时间50 min。     

Deformation characteristics,mechanisms, and influencing factors of hydrodynamic pressure landslides in the Three Gorges Reservoir: a case study and model test study

Bulletin of Engineering Geology and the Environment - Hydrodynamic Pressure landslides are the most typical landslides affected by the water level in the Three Gorges Reservoir. These types of...     

黑小麦麦麸戊聚糖的提取、纯化与组成分析

对黑小麦麦麸戊聚糖进行提取、纯化及组成分析。分别以H2O、Ba(OH)2和Na(OH)2为提取介质,提取水溶性和水不溶性戊聚糖;采用(NH4)2SO4分级沉淀、乙醇分级沉淀、凝胶过滤柱层析等方法纯化戊聚糖粗提物,分析其得率和组成。结果表明:水提组分(WEP)主要由葡萄糖(Glc)、阿拉伯糖(Ara)和木糖(Xyl)组成,是β-葡聚糖(79%)和戊聚糖(21%)的混合物。NaOH碱提组分(AEP-Na)中Ara和Xyl含量相对较高,以戊聚糖为主要组成(71%),还含有29%的β-葡聚糖。Ba(OH)2碱提组分(AEP-Ba)主要由阿拉伯糖(Ara)和木糖(Xyl)组成,含有较纯的戊聚糖(96%)。WEP经35%饱和(NH4)2SO4溶液沉淀后,戊聚糖含量由纯化前的21%提高到35%。AEP-Na经DEAE-Sepharose CL-6B柱层析,分级组分AEP-Na1的单糖组成的物质的量比,即n(Ara)∶n(Xyl)∶n(Glc)=0.7∶1∶1.2,其中戊聚糖的n(Ara)/n(Xyl)=0.7。AEP-Ba经不同浓度乙醇沉淀分级组分的戊聚糖主要由Ara和Xyl组成。其n(Ara)/n(Xyl)在0.38~1.02之间,且Ara的取代度随着乙醇浓度的增加而增大。