4 research outputs found

    Two I-h-symmetry-breaking C-60 isomers stabilized by chlorination

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    通讯作者地址: Xie, SY (通讯作者), Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 2. Xiamen Univ, Dept Chem, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 电子邮件地址: [email protected] abiding surprise in fullerene science is that I-h-symmetric buckminsterfullerene C-60 (ref. 1) (I-h-C-60 or C-#1,812(60), the nomenclature specified by symmetry or by Fowler's spiral algorithm(2)) remains the sole C-60 species experimentally available. Setting it apart from the other 1,811 topological isomers (isobuckminsterfullerenes) is its exclusive conformity with the isolated-pentagon rule(3), which states that stable fullerenes have isolated pentagons. Although gas-phase existence of isobuckminsterfullerenes has long been suspected(4-7), synthetic efforts have yet to yield successful results. Here, we report the realization of two isobuckminsterfullerenes by means of chlorination of the respective C-2v-and C-s-symmetric C-60 cages. These chlorinated species, (C60Cl8)-C-#1,809(1) and (C60Cl12)-C-#1,804(2), were isolated in experimentally useful yields. Structural characterization by crystallography unambiguously established the unique pentagon-pentagon ring fusions. These distinct structural features are directly responsible for the regioselectivity observed in subsequent substitution of chlorines, and also render these unprecedented derivatives of C60 isomers important for resolving the long-standing puzzle of fullerene formation by the Stone-Wales transformation scheme(8-11).NNSF of China,20525103 ,20531050 ,20721001 , 20571062 ,20425312 973 Program 2007CB81530

    在矩形槽中采用圆盘式水分布器的槽内温度场分布的实验研究

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    搭建了一套采用圆盘式水分布器布水和矩形水槽蓄冷水的蓄冷系统。通过改变供、回水温度,调节流量,分别进行了蓄冷模式实验和静置模式实验。结果表明:在物性参数、几何参数以及运行工况参数稳定的条件下,槽内温度场主要受单个布水器出口流量的影响。合理有效的流量控制措施有利于提高蓄冷系统效率和冷水机组运行能效比;对于以日为周期的电价峰平谷段运行机制,静置后的蓄冷系统仍能满足间歇供冷要求,但蓄冷系统和冷水机组的效率均下降

    光子探测激光测距的目标跟踪建模与仿真

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    单个光子的探测技术能提升普通探测器的灵敏度,在测距方面有着很重要的应用价值。光子探测激光测距技术是对于在先验信息未知的情况下,从大量回波数据中提取目标的运动轨迹。文章通过模拟光子计数探测目标的回波信息,用图像处理的方法从大量的回波数据中提取了目标的运动轨迹,与目标理论运动轨迹相比,误差在5 m以内。光子探测激光测距可作为北斗导航系统的一个辅助定位模块,利用其近程定位优势解决了光缆巡线过程中由于外部环境导致的北斗终端定位不精准的问题
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