Ab Initio Study on the Mechanism of Cycloaddition Reaction between Silylene Carbene （H_2Si=C：） and Acetone

The mechanism of cycloaddition reaction between singlet silylene carbene and acetone has been investigated with CCSD(T)//MP2/6-31G method. From the potential energy profile, it can be predicted that the reaction has two competitive dominant reaction pathways. One consists of two steps: (1) the two reactants (R1, R2) firstly form a four-membered ring intermediate (INT4) through a barrier-free exothermic reaction of 585.9 kJ/mol; (2) Then intermediate (INT4) isomerizes to CH3-transfer product (P4.1) via a transition state (TS4.1) with energy barrier of 5.3 kJ/mol. The other is as follows: on the basis of intermediate (INT4) created between R1 and R2, intermediate (INT4) further reacts with acetone (R2) to form the intermediate (INT5) through a barrier-free exothermic reaction of 166.3 kJ/mol; Then, intermediate (INT5) isomerizes to a silicic bis-heterocyclic product (P5) via a transition state (TS5), for which the barrier is 54.9 kJ/mol. The presented rule of this reaction: the [2+2] cycloaddition effect between the π orbital of silylene carbene and the π orbital of π-bonded compounds leads to the formation of a four-membered ring intermediate (INT4); The unsaturated property of C atom from carbene in the four-membered ring intermediate (INT4) results in the generation of CH3-transfer product (P4.1) and silicic bis-heterocyclic compound (P5).     

Synthesis,Crystal Structure and Luminescent Property of an Eu~(3+) Complex

A new Eu(Ⅲ) complex, {[Eu(tta)2(C2H5OH)(NO3)]2(bmp)}·bmp(tta = 2-thenoyltrifluoro- acetonate, bmp = 2,2'-bipyrimidine), has been synthesized and characterized by elemental analysis, IR, luminescence and single-crystal X-ray diffraction analysis. The complex crystallizes in the monoclinic P21/n space group, with a = 11.894(6), b = 14.235(8), c = 19.078(10) , β = 103.423(9)o, V = 3142(3) 3, Z = 2, Mr = 1721.10, Dc = 1.819 g/cm3, F(000) = 1696, the final R = 0.0452 and wR = 0.1398 for 5375 observed reflections with I 2σ(I). In the complex, each Eu(Ⅲ) ion is coordinated with four oxygen atoms from two tta ligands and two nitrogen atoms from a bmp ligand, three oxygen atoms from one NO3- anion and one ethanol molecule, forming a distorted tricapped trigonal prism geometry. Luminescence measurement indicates that the europium complex is a strong red emitter in the solid state at room temperature.     

多靶标生物标志物检测的微流体磁敏生物传感器研制

将磁敏传感器与微流体测试卡集成,研制了可快速检测多靶标生物标志物的微流体免疫磁敏传感器。以3种消化系统肿瘤标志物(甲胎蛋白、癌胚抗原、糖链抗原)为模型靶标,对免疫反应各步反应的液体流速、免疫反应时间以及反应后的冲洗速度进行了优化,评价了多靶标同时检测的系统性能。在微流体磁敏生物传感器系统中,建立了血清样本中3种靶标同时检测的标准工作曲线,AFP、CEA和CA19-9的检出限分别达到0.1μg/L、0.1μg/L和30 U/mL,线性范围跨越4个数量级。微流体磁敏生物传感器可在30 min内完成多靶标生物标志物检测,临床血清样本的测试结果与ELISA法一致,具有检测时间短、灵敏度高的优点。     

Kinetic model of induced codeposition of Ni-Mo alloys

The kinetic model of induced codeposition of nickel-molybdenum alloys from ammoniun citrate solution was studied on rotating disk electrodes to predict the behavior of the electrode-position. The molybdate (MoO42-) could be firstly electro-chemically reduced to MoO2, and subsequently undergoes a chemical reduction with atomic hydrogen previously adsorbed on the inducing metal nickel to form molybdenum in alloys. The kinetic equations were derived, and the kinetic parameters were obtained from a comparison of experimental results and the kinetic equations. The electrochemical rate constants for discharge of nickel, molybdenum and water could been expressed as k1(E) = 1. 23 × 109 CNi exp( - 0.198FE/RT) mol/(dm2·s), k2(E) =3.28× 10-10 CMoexp( - 0. 208FE/ RT) mol/(dm2·s) and k3(E) = 1.27 × 10-6exp( - 0.062FE/ RT) mol/(dm2 · s), where CNi and CMo are the concentrations of the nickel ion and molybdate, respectively, and E is the applied potential vs. saturated calomel electrode (SCE). The codeposition p     

单层碳纳米管的化学修饰

单层碳纳米管 (SWNT)是 Iijima博士 [1]于 1 993年首次发现的 .它具有非常独特的物理和化学性质 ,因而成为近年来研究的热点问题 .随着单层碳纳米管的合成技术和纯化研究的不断完善 [2～ 5] ,关于它的研究方向开始转向化学反应和应用研究 .由于单层碳纳米管不溶于水或有机溶剂而限制了对其化学性质的研究 .单层碳纳米管的端头是由碳的五元环和六元环组成的半球形 .氧化作用可将该端头打开并转化为羧基 ,从而与其它的化学试剂发生反应 .Liu Jie等 [6] 用浓硫酸和浓硝酸的混合物氧化单层碳纳米管 ,将之裁剪成 1 50～ 80 0 nm的“短管”.在…     

正溴丁烷合成虚拟仿真系统的设计与辅助实验教学研究*

介绍了正溴丁烷合成虚拟仿真系统的设计与功能,并结合具体的教学实践和研究结果的对比分析,提出了虚实结合的混合式教学模式,这种教学模式能有效解决传统实验教学过程中实验预习效果差、过程性评价难的教学痛点。     

丝素纤维/硫酸钙抗感染骨材料的制备及性能

通过控制丝素蛋白自组装过程制备了溶液状态下的丝素纳米纤维(silk fibroin nanofibers,SFFs),与硫酸钙、万古霉素(vancomycin,VCM)复合,制备了VCM/CS/SFFs抗菌骨材料。通过SEM、XRD、紫外分光光度计、万能力学试验机、抑菌圈、MTT等手段分别研究了复合材料的微观形貌与结构、药物释放、力学、抑菌及细胞相容性等性能。结果显示,与水作为固化液相比,随着SFFs溶液(0.017 5~2.1 mg·m L~(-1))的加入,复合材料凝固时间可控,降解率逐渐降低,抗水性增强,韧性提高;同时随丝素纳米纤维含量的增加骨材料抗压强度表现为先增加后减小的趋势,一周内药物释放速率降低;材料同时具有抑菌作用;MTT实验结果显示,加入丝素纳米纤维后与纯的硫酸钙相比MC3T3细胞增殖明显。     

一种基于SWNTs/Nafion/CuNPs纳米复合材料的

通过电沉积金属铜于SWNTs/Nafion修饰的玻碳电极表面构建了一种经济且简单易制备的非酶尿酸传感器.采用扫描电镜和能谱仪表征了纳米材料的形貌和成分,并考察了不同扫速和pH值对修饰电极的影响.在优化条件下,尿酸的线性范围为0.1～1000 μmol·L-1,检出限(S/N =3)为0.058 5iμmol·L-1.采用标准加入法检测人体血清中尿酸的回收率为97.2％～103.9％,相对标准偏差(RSD)为0.04％～0.11％.该非酶法与GOD-POD酶法的结果高度一致,且传感器经济易制备、灵敏性高、稳定性好、重现性高.     

应力波和动光弹等差条纹的分析与判读

介绍了动光弹的基本原理，并从理论上回答了动光弹应用中的一些问题，如惯性力可否忽略等．并在总结回顾动光弹等差条纹级次判读方法的基础上，提出了把应力波理论与等差条纹分析判读相结合的方法，这样不仅使条纹判读的概念更清晰，而且可提高条纹分析和级次判读的准确性．     

Study of the primordial lithium abundance

Lithium isotopes have attracted an intense interest because the abundance of both 6Li and 6Li from big bang nucleosynthesis (BBN) is one of the puzzles in nuclear astrophysics. Many investigations of both astrophysical observation and nucleosynthesis calculation have been carried out to solve the puzzle, but it is not solved yet. Several nuclear reactions involving lithium have been indirectly measured at China Institute of Atomic Energy, Beijing. The Standard BBN (SBBN) network calculations are then perfo...