C59N和C19N晶体的合成

通过溶解C60的CCl4溶液在大气中的慢蒸发可以合成C59N和C19N晶体,这项实验结果为CnN(n≤59)晶体研究开辟了一种简单而有效的途径.     

C (2) N+1 Ruijsenaars–Schneider Models

We define the notion of C ⁽²⁾ _N+1Ruijsenaars–Schneider models and construct their Lax formulation. They are obtained by a particular folding of the A _2N+1 systems. Their commuting Hamiltonians are linear combinations of Koornwinder–van Diejen external fields Ruijsenaars–Schneider models, for specific values of the exponential one-body couplings but with the most general two double-poles structure as opposed to the formerly studied BC _N case. Extensions to the elliptic potentials are briefly discussed.     

C59N单分子整流器

通过将单个C59N分子置于双势垒隧道结中，从而利用单电子隧穿效应和C59N分子的特殊能级结构，我们成功地实现了一种新型的单分子整流器件．实验中这个整流器件的正向导通电压约为0．5-0．7V，反向击穿电压约为1．6—1．8V．理论分析表明，中性C59N分子的半占据费米能级以及在不同充电情况下费米能级的不对称移动是形成整流效应的主要原因．其构成原理也决定了该器件具有稳定、易重复的特点．     

(C60)N团簇稳定结构的遗传算法研究

采用Pacheco-Ramalho相互作用势,结合改进的遗传算法研究了(C60)N团簇(N=3～25)的稳定结构与“幻数“序列,并研究了(C60)N 团簇的势能变化.结果表明:团簇的稳定结构与构成团簇的C60分子数目有密切的关系.随着C60分子数目的增大,团簇的稳态结构呈现出由层状变为壳状,然后又转变为层状结构的变化趋势.随着组成C60分子数的增多,团簇中分子的平均势能呈下降的趋势,下降的幅度随着分子数的增大而越来越小.     

High-resolution solid-state 13C14N and 13C15N heteronuclear correlation spectroscopy

Two-dimensional heteronuclear correlation spectroscopy is applied to coupled carbon and nitrogen nuclei in single crystals of amino acids and peptides. High resolution is available because the spectra have the carbon chemical shift along one frequency axis and the nitrogen chemical shift (and the second-order quadrupole shift in the case of ¹⁴N) along the second frequency axis. These two-dimensional spectra enable direct measurements of resonance frequencies and dipole-dipole couplings that are useful in providing information about the structure, dynamics, and spectral characteristics of molecules.     

Chemical Synthesis of C3N and BC2N Compounds

A chemical reaction for the preparation of B-C-N compounds by using carbon tetrachloride （CC14）, boron tribromide （BBr3）, lithium nitride （Li3N） and sodium as reactants has been carried out at the temperature of 400℃. Measurements of FTIR, XRD, TEM and EELS show that two kinds of compounds have been formed in the prepared sample. One is hollow sphere-like C-N with an amorphous, structure; the other is piece-like polycrystalline B-C-N with the hexagonal structure. Their determined compositions are close to C3N and BC2N, respectively.     

Determination of the ~(12)C(p, γ)~(13)N reaction rates fromthe ~(12)C(~7Li,~6He)~(13)N reaction

The angular distribution of the 12C(7Li,6He)13N reaction at E(7Li) = 44.0 MeV was measured at the HI-13 tandem accelerator of Beijing, China. The asymptotic normalization coefficient (ANC) of 13N → 12C + p was derived to be (1.64 ± 0.11) fm-1/2 through the distorted wave Born approximation (DWBA) analysis. The ANC was then used to deduce the astrophysical S (E) factors and reaction rates for the 12C(p,γ)13N direct capture reaction at energies of astrophysical relevance.     

U(N) SP(N) O(3)的分支律

利用群的直乘分解公式,考虑U(N)群的[2a1b]表示按群链U(N)SP(N)O(3)的约化规则,给出了相应的比较简单的分支律递推公式.该公式在用计算机计算分支律时,不受秩和表示维数的限制.为求解这类问题的分支律提供了一种比较简单的算法.在简化同位旋1/2的单j费米子体系的母分系数计算中具有十分重要的意义.用同样的方法也可以求出群链U(N)O(N)O(3)的分支律.     

Resonance Raman excitation and electronic structure of the single bonded dimers (C ¯60)2 and (C 59N)2

Raman spectra are presented for the single bonded dimeric fullerene (C ₆₀ ^- ) ₂ and compared to optical spectra and Raman spectra of the isostructural and isoelectronic heterofullerene (C₅₉N)₂. The spectra of both materials exhibit strong correlations with respect to splitting, line position, and line intensity. This holds for non resonant excitation with blue and green lasers as well as for the strong resonances observed with red lasers. The latter observation is consistent with a downshift for the electronic transition energies as compared to C₆₀. The absorption edge of thin films of (C₅₉N)₂ was found at 1.4 eV. The three intercage modes were observed at 82, 103, and 111, and at 88, 98, and 106 cm^-1 for (C₅₉N)₂ and (C ₆₀ ^- ) ₂ , respectively. A surprising difference was found for the position of the pentagonal pinch modes in the two materials as they were observed at 1461 and at 1451 cm^-1, for (C₅₉N)₂ and (C ₆₀ ^- ) ₂ , respectively. This is interpreted as a consequence of some characteristic differences in the electronic structure of the two compounds. Received 25 January 2000 and Received in final form 10 April 2000     

New determination of the astrophysical 13C( p, γ) 14N S(E) factors and reaction rates via the 13C(7Li, 6He) 14N reaction

The ¹³C(⁷Li, ⁶He) ¹⁴ N_0,1 reactions were measured at E (⁷Li) = 34 MeV with the Q3D magnetic spectrometer of the HI-13 tandem accelerator, and the first peaks of the angular distributions were obtained for the first time. The ¹⁴N_0,1 proton spectroscopic factors were extracted to be 0.67±0.09 and 0.73±0.10 , respectively. Using the ¹³C(p, ??) ¹⁴N direct capture S _dc(E) factors derived by the spectroscopic factors, the direct measurement data for both 1^? and 0^? resonances were well fitted via updating the resonance parameters, and then the total astrophysical ¹³C(p, ??) ¹⁴N S(E) factors and reaction rates were determined at stellar energies. The present work offers an independent examination to the existing results of the ¹³ C(p, ??) ¹⁴N reaction.     

混配配合物[Co(cpida)(C7H5N2)2]·C7H5N2·5H2O

在溶液中用N-(邻苯甲酸基)-亚氨基二乙酸、苯并咪唑和Co(Ac)2·4H2O进行自组装合成了标题三元金属混配配合物.用元素分析、红外光谱、单晶衍射对配合物的组成和结构进行了表征,确定配体N-(邻苯甲酸基)-亚氨基二乙酸中的3个羧基为单齿形式与中心金属钴离子配位.     

β—C3N4研究的新进展

β－Ｃ３Ｎ４的研究是近年来凝聚态物理和材料科学研究的热门课题之一。我们利用偏压辅助热解化学气相沉积方法，首次获得１－３μｍ，横截面尺寸在３００－５００ｎｍ和β－Ｃ３Ｎ４六棱体，其晶格常数α＝６．２４Ａ和ｃ＝２．３６Ａ，Ｎ：Ｃ＝１．３０－１．４０。     

石墨相C3N4的高温高压研究

为了得到超硬相的C3N4,利用石墨相C3N4(gC3N4)为实验的初始原料,利用六面顶压机高温高压实验技术,对gC3N4进行了高温高压研究.实验结果表明,在5.2 GPa、600 ℃和5.2 GPa、800 ℃两个压力和温度点,制备的样品经过X射线衍射(XRD)分析,样品仍然为gC3N4,当温度升到1000 ℃时,发现样品发生了变化,经XRD和X光电子能谱（XPS）分析,gC3N4完全分解为石墨.     

紫外薄层色谱法分离C15H18N4SO2和C13H19N3SO4

采用紫外薄层色谱法在硅胶GF254板上分离N-{2-[(2,2-二氰基-乙烯基)-甲基-氨基]-丙基}-4-甲基-苯磺酰胺(C_(15)H_(18)N_4SO_2)和4-甲基-N-{2-[甲基-(2-硝基-乙烯基)-氨基]-丙基}-苯磺酰胺(C_(13)H_(19)N_3SO_4)二种有机物的方法。硅胶GF254板由0.27mol/L,pH=7的EDTA溶液修饰,避免了这两种样品与板上少量无机金属离子发生络合作用;展开剂为乙酸乙酯-石油醚-乙醇-37.5%氨水(体积比为10∶10∶1∶1)。C_(15)H_(18)N_4SO_2和C_(13)H_(19)N_3SO_4的Rf值分别为0.64和0.48。用紫外薄层色谱法分离C_(15)H_(18)N_4SO_2和C_(13)H_(19)N_3SO_4具有操作简单,灵敏,准确的特点。     

Synthesis and characterization of Ni(II) complex functionalized silica-based magnetic nanocatalyst and its application in C–N and C–C cross-coupling reactions

Molecular Diversity - A new magnetically recoverable silica-based nickel(II) nanocatalyst was synthesized by a simple cost-effective procedure, which was characterized by TEM, SEM, XRD, VSM...     

三种N湮没势和+~(12)C非弹性散射

在Glauber多重散射理论框架下 ,使用跃迁密度方法和 3种 NN湮没势 ,计算了入射动量为6 0 0MeV c的反质子在12 C上的非弹性散射微分截面 .理论曲线与实验数据符合得甚好     

甲醛缩氨基脲及其有关化合物的~(15)N和~(13)C核磁共振研究

本文测定了12个甲醛缩氨基脲类化合物的~(15)N和~(13)C NMR谱,研究并对比了不同取代基对~(15)N和~(13)C化学位移的影响,结果表明:~(15)N化学位移对分子结构和取代基的电子效应更加敏感,变化范围更大.对N-苯甲醛缩氨基脲~(15)N化学位移与Hammatt取代常数σ的相关性进行了研究,并与苯胺的取代效应作了对比.     

Ni(C3H10N2)2NO2(ClO4)晶体的ESR研究

报道了Ni(C₃H₁₀N₂)₂NO₂(ClO₄)晶体在T=1.5K温度和W波段的ESR实验.建立了d⁸离子基态³A₂(F)的零场分裂参量D,E,和g因子与斜方对称晶场势参量间的关系,并应用于Ni(C₃H₁₀N₂)₂NO₂(ClO₄)晶体.计算值与实验数据符合很好,表明所给关系式是合理的.