丁烯催化裂解反应中的C-H键型副反应和化学平衡问题

用小型固定床反应器以及氨气程序升温脱附(NH<,3>-TPD)和吡啶吸附红外光谱(Py-IR)研究了醚后碳四液化气中的丁烯在改性纳米ZSM-5沸石催化剂上的催化裂解反应.结果表明,丁烯催化裂解反应的丙烯选择性主要受氢转移和脱氢反应制约.这些C-H键型反应生成烷烃和芳烃副产物,并导致催化剂积炭.低温有利于氢转移(尤其异丁...     

超分子化合物[C6H11NH3]6[P2Mo18O62]·4H2O的水热法合成及结构

超分子化合物[C6H11NH3]6[P2Mo18O62]·4H2O的水热法合成及结构;Wells-Dawson结构;杂多化合物     

Effect of Carbonized Conditions on Residual Strain and Crystallinity Quality of Heteroepitaxial Growth 3C-SiC Films

Heteroepitaxial growth of SiC on n-Si（111） substrates is performed by a low pressure chemicaJ vapor deposition process. The effects of different carbonized temperature and carbonized time on the crystalline quality and the residual strain of 3C-SiC films are discussed. The results show that the residual strain is obviously reduced and the crystalline quality is greatly improved at the best carbonized temperature of 1000℃ and the carbonized time of 5 min. Under these optimized carbonization conditions, thick epitaxial films of about 15 μm with good crystalline quality and low residual strain can be obtained.     

First-Principles Study of Structural and Electronic Properties of Layered B2CN Crystals

Based on the hexagonal BN structure, six possible layered B~ CN structures are constructed. Their total energies, lattice constants as well as electronic properties are calculated using the ab initio pseudopotential density functional method within the local density approximation. The calculated results show that the B2 CN-V configuration with AA stacking sequence is the most stable among the six B2CN layered structures. The characteristics of electronic structures indicate that the B2 CN-V shows metallicity, which mainly comes from -B1-C-B1-C- chains.     

基于有机磷酸类MOFs前驱体制备Ni2P/C复合材料

以镍为金属中心、 对二甲苯二磷酸为有机配体, 构筑了一种有机磷酸类Ni-MOF前驱体, 再经过一步碳化, 原位制备出多孔碳包覆Ni₂P纳米颗粒的复合材料. 该复合材料保留了前驱体的片状形貌, 比表面积可达202 m²/g, 复合材料中的Ni₂P纳米颗粒具有良好的结晶度, 颗粒均匀且无团聚现象. 在锂离子电池性能测试中, 该Ni₂P/C复合结构在缓解材料体积膨胀的同时提高了材料的电子和离子电导率, 进而提高了材料的电化学性能. 在0.2 C的电流密度下, 材料首次充、 放电比容量分别为247和226 mA·h·g^-1, 库仑效率可达91.7%, 循环200圈后, 库仑效率接近100%.     

（四甲基二硅撑）双（3—三甲硅基环戊二烯基）—四羰基二铁…

标题化合物（Ｍｅ２ＳｉＳｉＭｅ２）〔η＾５－（３－Ｍｅ３ＳｉＣ５Ｈ３）Ｆｅ（ＣＯ）２〕２／（μ－ＣＯ）２（Ａ）分子中的Ｆｅ－Ｆｅ键被钠汞齐还原断裂，生成相应的双铁负离子，分别与ＭｅＣＯＣｌ、ＰｈＣＯＣｌ、ＰｈＣＨ２Ｃｌ、ＣｌＣＨ２ＣＯＯＣ２Ｈ５和Ｐｈ３ＳｎＣｌ进行亲核取代反应，生成在铁原子上引入相应取代基的产物（Ｍｅ２ＳｉＳｉＭｅ２）〔η＾５－（３－Ｍｅ３ＳｉＣ５Ｈ３）Ｆｅ（ＣＯ）２Ｒ〕２（Ｒ：Ｍ     

新型除草剂丙酯草醚A环14C均标记合成和鉴定

以U-¹⁴C-对氨基苯甲酸为前体, 通过酯化、缩合、还原和取代四步反应获得了A环¹⁴C均标记的丙酯草醚, 用PHPLC对其进行纯化. 采用HPLC-MS(ESI), MS(EI)和¹H NMR验证了其结构, 通过HPLC(外标法)确定其化学纯度大于98%; HPLC-LSC和TLC-IIA两种方法分析表明, 其放射化学纯度大于98%, 其比活度为1.089±0.011 mCi/mmol. 合成的化学收率和放化收率均为53%.     

低血铅水平与免疫球蛋白和淋巴细胞相关性

目的：探讨低铅水平对IgA、 IgG 、 IgM、 C3、 C4、 B淋巴细胞的影响。方法用石墨炉原子吸收光谱法对39名印刷印染工龄5年以上工人进行血铅测定,另选择距污染源较远且无水系联系的,不受工业污染的,从未接触过重金属的为对照组,分别对两组用免疫比浊法进行（ IgA、IgG、 IgM、 C3和C4）5项测定,流式细胞仪检测血B淋巴细胞水平,全自动生化仪检测白细胞数、总淋巴细胞绝对数和百分比。结果高低铅两组IgA、 IgG 、 IgM、 C3水平比较差异有统计学意义（P＜0.05）,白细胞总数、淋巴细胞百分比均低于低铅组（P＜0.05）,总淋巴细胞百分比和NK淋巴细胞亚群的绝对数和百分比却低于低铅组（ P＜0.05）。结论高血铅对体液免疫功能有一定的影响。     

聚合物异核交叉弛豫及二维NOE谱

The heteronuclear cross-relaxation rates in polymers were determined by selective and conventional ~(13)C spin-lattice relaxation experiments, the proton-carbon distances were calculated by the theoretical formula, and two-dimensional NOE spectra of the polymers were also measured. The results showed that (1) the measured proton-carbon distances coincide with the distances from molecular models, (2) there is the observable dipolar cross-relaxation effect between the quaternary carbons and their neighboring protons, and (3) the optimum mixing times depend on the relaxation properties of the proton and carbon.