精确计算SM中混合链图传播下e■→f■反应截面

采用电弱统一标准模型（SM）,分析了由参与电弱相互作用的各种混合圈构成的光子γ,中间玻色子Zo重整化链图传播子的构架方式,并完成了相关解析计算,进而获得了γ,Z₀重整化混合圈链图传播子的解析计算结果.作者又将γ,Z₀混合圈链图传播子D_γ^{（m-chain）}（s）,D_Z^{（m-chain）}（s）和D_γZ^{（m-chain）}（s）应用到粒子反应e■→f■中,精确计算了e■→f■反应总截面σ_SM^（chain）.通过与LEP实验组的实验观测值的比较,发现本文理论计算结果比最低（树图）阶的结果与实验吻合更好.     

电磁场作用下溶质元素在镁合金AZ61的分布

通过研究不同外场作用下镁合金AZ61的凝固组织，发现在静磁场单独作用时的晶界主要由镁基体和连续的网状化合物组成，在静磁场与交流电组合外场下的晶界主要由镁基体和网状及点状Mg-Al-Zn化合物组成，而在静磁场与直流电组合外场下晶界上的连续网状化合物彻底消失，化合物以不连续的薄片形态分布于镁基体上.相对于单一静磁场作用时，静磁场与电流共同作用时提高了镁合金晶内溶质含量，降低了晶界上的溶质含量. 关键词： 镁合金 静磁场 电流 晶内溶质含量     

区分化学分析法与仪器分析法适用性的实践教学探索

根据方法原理,分析化学的常用分析方法可分为化学分析法和仪器分析法。高灵敏度、高选择性、高自动化、数字化和智能化已成为分析化学的发展方向,仪器分析法成为了分析化学发展的主流和热点。因此,在校本科生往往忽视化学分析法的重要作用以及适用范围,陷入仪器分析法为万能分析方法的误区。本文选用络合滴定法和原子吸收光谱法分别对常量含铅样品进行测试,通过考察测试结果的相对误差大小,探索了化学分析法和仪器分析法的适用范围,从而纠正了在校本科生的唯仪器分析法的错误观念。     

聚合物支载过硼酸盐的氧化性能研究

为了提高过硼酸钠的稳定性及控制氧化速度,本文将过硼酸钠接于高分子载体上,制成聚合物支载型氧化剂。本研究首次将过硼酸钠与强碱型离子交换树脂作用,制成聚合物氧化剂,并将它用于芳醛、芳胺的氧化。特别是:后处理简便,只需过滤即分离出产物;反应过程中可以使用过量的氧化剂,以增加反应速率和产率且聚合物氧化剂可再生循环使用,提高了使用效率,降低了成本。     

In situ STM studies of electrochemical growth of nanostructured Ni films and their anomalous IR properties

We have extended the study of anomalous IR properties, which were initially discovered on nanostructured films of platinum group metals and alloys, to nanostructured films of nickel, a member of the iron group triad, and broadened the fundamental knowledge on this subject. Nanostructured thin films of nickel supported on glassy carbon [nm-Ni/GC(n)] were prepared by electrochemical deposition under cyclic voltammetric conditions, and the thickness of films was altered systematically by varying the number (n) of potential cycling within a defined potential range for electrodeposition. Electrochemical in situ scanning tunneling microscopy (STM) was employed to monitor the electrochemical growth of nanostructured Ni films. These in situ STM images illustrated that, along the increase of the film thickness, Ni films have undergone a transformation from layer structure to island structure and finally to lumpish arris structure. Investigations by in situ FTIR spectroscopy employing adsorbed CO as the probe revealed that these nanostructures of Ni films yield abnormal IR features, Fano-like IR features, and normal IR features, respectively. The IR bands of CO adsorbed on Ni thin films of a layer structure were inverted in their direction and enhanced in their intensity up to 15.5 times on an nm-Ni/GC(4) electrode. The Fano-like IR features, which are defined as a bipolar band with its negative-going peak on the low wavenumber side and its positive-going peak on the high wavenumber side, are observed for the first time on Ni thin films of an island nanostructure, i.e., at the nm-Ni/GC(16) electrode. IR features changed to normal absorption in CO adsorbed on the nm-Ni/GC(25) electrode, i.e., that with lumpish arris nanostructured Ni film of a larger thickness.     

Boosting the electrocatalytic performance of NiFe layered double hydroxides for the oxygen evolution reaction by exposing the highly active edge plane (012)

The intrinsic activity of NiFe layer double hydroxides (LDHs) for the oxygen evolution reaction (OER) suffers from its predominantly exposed (003) basal plane, which is thought to have poor activity. Herein, we construct a hierarchal structure of NiFe LDH nanosheet-arrays-on-microplates (NiFe NSAs-MPs) to elevate the electrocatalytic activity of NiFe LDHs for the OER by exposing a high-activity plane, such as the (012) edge plane. It is surprising that the NiFe NSAs-MPs show activity of 100 mA cm⁻² at an overpotential (η) of 250 mV, which is five times higher than that of (003) plane-dominated NiFe LDH microsheet arrays (NiFe MSAs) at the same η, representing the excellent electrocatalytic activity for the OER in alkaline media. Besides, we analyzed the OER activities of the (003) basal plane and the (012) and (110) edge planes of NiFe LDHs by density functional theory with on-site Coulomb interactions (DFT+U), and the calculation results indicated that the (012) edge plane exhibits the best catalytic performance among the various crystal planes because of the oxygen coordination of the Fe site, which is responsible for the high catalytic activity of NiFe NSAs-MPs.

The (012) edge plane of NiFe layer double hydroxides (LDHs) has been proven to be a highly active plane for water oxidation.     

异丁烯在不同硅铝比的NanZSM-5型分子筛中的吸附：分子模拟研究

Frameworks of NanZSM-5 type zeolites with various Si/A1 ratios have been constructed and optimized with molecular dynamic quench simulation. The results show that the structure parameters of NanZSM-5 type zeolite, including the bond length and atomic charges, are consistent with those predicted by ab initio cluster calculations. It was also observed that atomic charges of Si atoms were shifted to higher field in NanZSM-5 type zeolite with lower Si/Al ratio. Then, the adsorption of isobutene on NanZSM-5 with various Si/Al ratios has been investigated using grand canonical ensemble Monte Carlo simulation and Cvff-300-1.01 forcefield. The simulated adsorption amount was in good agreement with the experimental data. Based on these facts, the effects of Si/Al ratio on the adsorption amount and adsorption isotherms of isobutene on NanZSM-5 were predicted. The results indicated that Si/Al ratio was important for the adsorption of isobutene and the adsorption amount was decreased as the Si/Al ratio was increased, which can be explained that the atomic charge of Na^＋ cation would influence greatly the π electrons of the isobutene double bond due to the Coulomb force. In addition, the adsorption sites of isobutene and interaction energy of isobutene with NanZSM-5 were also discussed.     

Pyrolysis of waste tire on ZSM-5 zeolite with enhanced catalytic activities

Catalytic copyrolysis of waste tires over ZSM-5 zeolite with lubricant base oil (LBO) was undertaken at 430 °C under nitrogen atmosphere in a batch mode, and the pyrolysis oils were characterized using gas chromatography/mass spectroscopy (GC-MS). By combining with LBO, the ZSM-5 catalyzed pyrolysis system of tires has a sharply enhanced degradation rate. Compared to the pyrolysis without LBO, the liquid yield is increased from 33.6% to 48.0%, while the gas and the residue yields are decreased. In the pyrolysis oils, the content of heavy components is decreased and the content of light oils (n-C ≤ 12) is increased from 77.8%(without LBO) to 83.1%(with LBO); especially, the content of C₁₀ components has a sharp increase. Moreover, the liquid compositions are changed. Particularly, the percentage of limonene increased dramatically from 7.54% for thermal degradation to 13.58%. These results suggest that the enhanced catalytic effects on pyrolysis of tires in the catalytic systems are due to the improved interactions between tires and catalysts with the help of LBO. Therefore, it is possible to improve the process economics of scrap tires by catalytic copyrolysis with LBO, which can not only increase the pyrolysis rate remarkably but also produce high-value oil products.     

CO2-3对羟基乙叉二膦酸镀铜液的影响

研究羟基乙叉二膦酸(HEDPA)镀铜液中CO2-3含量对电沉积时阴、阳极过程及镀层的择优取向的影响. 通过分析阴、阳极的动电位极化曲线, 发现镀液中逐渐加入的CO2-3提高了阴极的极化, 使电结晶晶粒细化, 直至达到稳定; 同时促进了铜阳极的溶解. 而X射线衍射(XRD)结果表明, 铜镀层的晶面择优取向从(222)逐渐向(111)转变. 通过镀液中固体络合物的红外光谱分析表明, CO2-3的加入以第二配体的方式进入该镀液的放电络合离子结构中, 参与Cu2+的络合, 形成更稳定的络合物, 从而导致铜沉积电位负移, 镀层(111)晶面取向增强.     

离子化合物[2，6-bis(Benzimidazol-2-yl)pyridineH2]2+·[SbCl5]2-的合成、晶体结构及荧光性质

利用邻苯二胺、2,6-吡啶二甲酸与三氯化锑在盐酸溶液中经水热反应,合成了一种新的离子型化合物[2,6-bis(Benzimidazol-2-yl)pyridineH₂]²⁺·[SbCl₅]^2-。通过化学分析、元素分析、热重分析、红外光谱及荧光光谱对结构和性质进行了表征,用X-射线单晶衍射测定了该化合物的晶体结构。化合物的晶体属三斜晶系,P1空间群。Sb³⁺与其周围5个氯离子配位,构成一个畸变四方锥构型[SbCl₅]^2-配位结构,2个配阴离子[SbCl₅]^2-之间通过Sb(1)…Cl(1)^ⅱ次级键形成四元环状结构,并与2,6-二(苯并咪唑-2′)吡啶两价阳离子,通过离子键及氢键形成三维网状离子化合物晶体。该化合物具有很好的荧光特性。