碘化钾催化CO_2与氧化苯乙烯合成苯乙烯环状碳酸酯条件的优化

用碘化钾催化CO2与氧化苯乙烯(SO)合成苯乙烯环状碳酸酯,分别从溶剂、催化剂用量、温度、CO2压力和反应时间进行探讨,得出了最佳条件.结果表明:以无水乙醇为溶剂,催化剂用量r(KI∶SO)=1∶250,在170℃,CO2压力5 MPa,反应时间5 h,苯乙烯环状碳酸酯的产率和选择性均达到100%.     

Reductive leaching of low-grade manganese ore with pre-processed cornstalk

Cornstalk is usually directly used as a reductant in reductive leaching manganese. However, low utilization of cornstalk makes low manganese dissolution ratio. In the research, pretreatment for cornstalk was proposed to improve manganese dissolution ratio. Cornstalk was preprocessed by a heated sulfuric acid solution (1.2 M of sulfuric acid concentration) for 10 min at 80°C. Thereafter, both the pretreated solu-tion and the residue were used as a reductant for manganese leaching. This method not only exhibited superior activity for hydrolyzing corn-stalk but also enhanced manganese dissolution. These effects were attributed to an increase in the amount of reductive sugars resulting from lignin hydrolysis. Through acid pretreatment for cornstalk, the manganese dissolution ratio was improved from 50.14%to 83.46%. The pre-sent work demonstrates for the first time the effective acid pretreatment of cornstalk to provide a cost-effective reductant for manganese leaching.     

尖晶石型LiMn2O4的溶胶凝胶法制备

采用溶胶 凝胶法合成了锂离子电池正极材料LiMn2O4·研究了干凝胶制备锰酸锂的机理·由于干凝胶燃烧时生成的产物颗粒很细,燃烧过程中就有大量的锰酸锂生成,剩下的Mn3O4和Li2O2在300℃左右已完全转化为锰酸锂,大大降低了合成温度·通过对700℃合成的锰酸锂XRD分析表明,样品的衍射峰峰形尖锐,晶型发育良好·考察了pH值对合成样品粒度及电化学性能的影响,SEM分析表明,随pH值增加,所得溶胶制备的锰酸锂电化学容量增加,当pH=6 0时合成样品颗粒分布均匀,达到亚微米级·以0 1C的电流、电压范围3 30～4 35V充放电测试表明,该条件下合成的样品初始放电容量为121.0mAh·g-1,显...     

淡水养殖的珍珠贝壳热分解行为研究

采用FTIR实时红外检测方法研究室温～600 ℃范围内贝壳珍珠层的红外光谱特征,结合热重分析考察淡水养殖珍珠贝壳中的有机和无机组分变化情况.采用扫描电子显微镜观察珍珠层的微结构,并利用X-射线衍射方法测量不同温度下贝壳中无机成分的晶相变化.结果表明,贝壳中氨基酸类有机物热分解后部分以胺的形式挥发,另一部分则转化为不可挥...     

Synthesis of self-assembled needle-shaped calcium carbonate superstructures

Novel self-assembled calcium carbonate (CaCO₃) crystals exhibiting the morphology of well-defined needles were synthesized by a simple precipitation reaction in the presence of octadecyl dihydrogen phosphate (ODP) as a crystal additive. The CaCO₃ obtained by this method is hydrophobic, making it likely to be used widely in industry. The resulting products were characterized by powder X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy and contact angle experiments. The results indicated that ODP plays an important role in determining the structure, morphology and hydrophobicity of CaCO₃ crystals.     

辽河西部凹陷曙103块潜山油藏储层特征

辽河西部凹陷曙 10 3块潜山由中元古界长城系高于庄组泥粉晶白云岩、灰质白云岩和白云质灰岩组成 ,其主要的储集空间包括溶蚀孔洞、构造裂缝及微孔微缝等。该区溶蚀孔洞非常发育 ,根据其规模可分为大、中、小型溶洞及溶孔 ,其中大、中型溶洞常因坍塌和充填而失去储集能力 ,而小型溶洞和溶孔等则成为该潜山的主要储集空间。高角度构造缝对该储层储集空间的贡献最大 ,其优势发育方位为北东—南西向 ,与区域构造线方位一致。压力测试结果表明 ,该区储层中显微级的微孔和微裂缝经过一段时间的开采后 ,替代宏观溶孔和裂缝而成为主要的供油空间 ,这表明它也是很重要的储集空间。对各井开采现状及采油层段的对比研究表明 ,曙 10 3块潜山储层的发育受古地貌位置、构造位置及沉积旋回的控制 ,好的储层段主要分布在潜山顶面及地貌高点     

Fe-Cu合金体系中Cu析出规律

利用扫描电镜及能谱分析研究了Fe-7.8%Cu和Fe-2.1%Cu两种合金不同温度下铜的析出分布规律,以及合金中MnS夹杂物对铜析出的影响.部分试样加热到1600℃保温20 min后直接淬火得到;其他试样1 600℃保温20 min,炉冷到特定温度再保温20 min后淬火得到.结果表明:Fe-7.8%Cu合金在1600℃下淬火,含铜相在晶界、晶内均有析出;在1200℃下淬火,含铜相沿晶界析出;而1000℃淬火则有较大尺寸的ε-Cu相沿晶界析出.Fe-2.1%Cu合金在1 600℃和1 000℃下淬火,含铜相都沿晶界析出;而800℃淬火ε-Cu相在晶内析出.合金中MnS夹杂可以作为铜析出的有效形核核心.     

磁电阻效应的研究进展

氧化物巨磁电阻效应在物理研究和磁存储、读写等实验应用方面的重要性,使得对该领域的研究成为当今凝聚态物理学和材料科学学中最前沿的领域之一.     

High concentration retene and methylretene in Silurian carbonate of Michigan Basin

Retene and methylretene have been identified by gas chromatography-mass spectrometry in aromatic hydrocarbon fractions of Silurian carbonate extracts of the Michigan Basin. Retene identified in pre-Devonian carbonates indicates that the compound not only is the biomarker of higher plants but also derived from alga or bacterium. The geochemical significance of methylretene has been discussed.