Ω Production and Corresponding Ratio of Antiparticle to Particle in Relativistic Nucleus-Nucleus

We use the event generator LUClAE to analyze the WA85 data of ratio of Ω^- to Ω^- in reaction (200A GeV/c)S + W. The result indicates that the reproduction of WA85 data might be achieved in hadronic rescattering regime of LUCIAE and might need not to rely on the formation of QGP.     

不同生长期当归1H NMR指纹图谱的研究

利用¹H NMR法测定27个不同生长期的当归提取物,对当归的主要活性成分阿魏酸、藁本内酯、当归多糖进行了初步归属,用特征峰相对峰面积表示3种活性成分的相对含量,并对它们在生长过程中的含量变化进行分析. 数据分析显示,当归中阿魏酸、藁本内酯、当归多糖的含量在第1年变化较为平稳,第2年和第3年变化相对较为活跃,而在当归的生长周期内,当归多糖的含量变化明显大于其他两种活性成分,为参与代谢活动的主要活性成分. 结果证实,通过对照¹H NMR指纹图谱, 将相对含量法与主成分分析法相结合,能对不同生长期的当归药材中的活性成分进行宏观评价和分析,可作为植物药材代谢组学的研究方法.     

无机-有机杂化非线性光学晶体材料LAP和d-LAP晶体红外吸收边计算

根据双原子谐振子模型近似,提出了估算分子晶体材料红外吸收边的理论方法,然后利用超分子量子化学从头算,计算了L-精氨酸一水磷酸盐(LAP)晶体和氘化L-精氨酸一水磷酸盐(d-LAP)晶体单元超分子的红外振动光谱,其中LAP晶体超分子计算值与晶体红外光谱实验值吻合,表明超分子计算能有效地模拟无机-有机杂化非线性光学晶体的红外振动光谱。在归属了超分子重要基频线后,分析其红外强度,并估算了泛频频率。根据我们提出的方法,估算了这两种晶体的红外吸收边,结果与实验值较吻合。表明我们建议的理论方法是合理的。此外,通过计算表明,如果非线性光学晶体材料的红外吸收边是由与活泼H有关的伸缩振动泛频频率决定,那么活泼H的氘化是一种改善红外吸收边的有效途径。     

在RHIC的极限碎裂和Φ介子产生(英文)

利用强子和串级联模型LUCIAE研究了PHOBOS的极限碎裂等以及在PHIC进行的Au+Au碰撞中带电粒子多重性的经验标度规律. 对Φ介子的产生机制也通过与带电粒子多重性的比较进行类似的研究. 结果似乎表明在串级碎裂模型中带电粒子和Φ介子有共同的产生机制. 还讨论了PHOBOS经验标度规律的模型依赖性.The PHOBOS’s limiting fragmentation etc. three empirical scaling rules for charged multiplicity in Au+Au collisions at RHIC are investigated by ahadron and string cascade model LUCIAE. Similar studies are performed for the meson exploring its production mechanism via comparing with the charged multiplicity. The LUCIAE results for charged multiplicity are compatible with PHOBOS observations. However, for the  meson the three empirical scaling rules are either kept only or kept better in the LUCIAE calculations without reduction mechanism of the s quark suppression extra introduced for the strangeness in LUCIAE model. These results seem indicating a universal production mechanism for charged particle and  meson in string fragmentation regime. It is discussed that the PHOBOS’s empirical scaling rules are model dependent indeed.     

Net Charge Fluctuation and String Fragmentation

We present the simulation results of the net charge fluctuation in Au Au collisions at /Snn=130 GeV froma dynamic model, JPCIAE, and its revisions. The simulations are done for the quark-gluon matter, the directly producedpions, the pion matter, and the hadron matter. The simulated net charge fluctuation of the quark-gluon matter is closeto the thermal model prediction for the quark-gluon gas. However, the discrepancy exists comparing the simulated netcharge fluctuation for directly produced pions and the pion matter with the thermal model prediction for pion gas andthe resonance pion gas, respectively. The net charge fluctuation of hadron matter from default JPCIAE simulations isnearly 3.5 times larger than quark-gluon matter. A discussion is given for the net charge fluctuation as an evidence ofQGP phase transition.     

Theoretical Studies on the First Hyperpolarizabilities of One-dimensional Donor-bridge-acceptor Chromophores and New Applications of BLA in Determining Molecular First Hyperpolarizabilities

We present a quantum-chemical analysis of the relationship between the bond length alteration （BLA） and the static first hyperpolarizability of a series of one-dimensional （1D） chromophores with donor-bridge-acceptor （D-B-A） structures. The calculated results show that the parameter BLA can be considered as an indicator to evaluate the molecular first hyper- polarizability. Along the direction of molecular ground-state dipole moments, the evolutions of BLA can be classified into three categories： the first is a non-monotonic line, which represents most chromophores; the second is monotonic increasing; and the third, contrarily, is monotonic decreasing. On the whole, the first hyperpolarizabilities of these studied chromophores are the monotonic functions of BLA along the direction of dipole moments. Therefore, the first hyperpolarizability of these 1D chromophores can be preliminarily evaluated in terms of the development of BLA without a rigorous computation. In other words, one can roughly estimate the relative magnitude of the first hyperpolarizability according to the optimized geometry.     

Ligand-controlled First Hyperpolarizabilities of a Series of Tetrahedral Iridium Clusters Ir4（CO）9L： a TDDFT Study

A series of tetrahedral iridium carbonyl clusters coordinated by systematically varied series of ligands have been studied by TDDFT method focusing on their electronic and non- linear optical properties. The clusters of Ir4（CO）12 （1）, Ir4（μ-CO）3（CO）9 （2）, Ir4（μ-L）（CO）10 （L = dppm 3, dppe 4, （Ph2P）2CHMe 5, Ph2P（CH2）3PPh2 6） and Ir4（CO）10（phen） （phen = 1,10-phen- anthroline） （7） exhibit the first static hyperpolarizabilities of medium magnitude （βtot-10×10^-30 esu）. The second order nonlinear optical response of the seven clusters increase from 0 to 23 ×10^-30 esu; the high symmetric cluster Ir4（CO）12 debases its symmetry and presents the second order nonlinear optical behavior as the coordination style of some carbonyls changes to bridge style, and then the response increases regularly with the systematical variation of the ligands. The origination of the first hyperpolarizability is discussed by the expanded orbital decomposition scheme. The results suggest the d-d electron transition from the apical iridium atom to the other three Ir atoms inside the metal skeleton, and d-πelectron transitions from metals to carbonyls are responsible for the first hyperpolarizabilities. Particularly, for cluster 7, the charge transfer from d orbitals of iridium to π＊ orbirals of phenanthroline originates the first hyperpolarizabilities.     

A note on maximizing the permanent of a positive definite hermitian matrix,given the eigenvalues ∗

As a step toward understanding the unsolved problem of determining how large the permanent of a positive semi-definite matrix can be, given the eigenvalues, we note that a necessary condition for A to be a permanent maximizing matrix is that A commute with its permanental adjoint.     

Theoretical Studies on the Binding of Cd~（2＋） to Uracil and Its Thio-derivatives

The interaction of Cd2+ with uracil,2-thiouracil,4-thiouracil and 2,4-dithiouracil have been investigated by the density functional theory(DFT) calculations.For uracil and 2,4-dithiouracil,where the two basic sites are the same,Cd2+ attachment to the heteroatom at position 4 is preferred.However,for the systems where both types of basic centers,a carbonyl and a thiocarbonyl groups,are present,Cd2+ association with sulfur is favorable.The enhanced stability of these enolic and thiol forms comes from Cd2+ interaction with two basic sites simultaneously,which thereby triggers a significant aromatization of the ring.More significantly,the Cd2+ binding energy with uracil and its thio-derivatives is larger than the tautomerization barriers connecting the diketo-like forms with the corresponding enolic-like tautomers.Consequently,when associated with Cd2+,all tautomers are energetically accessible and should be observed in the gas phase.     

A note on maximizing the permanent of a positive definite hermitian matrix, given the eigenvalues

As a step toward understanding the unsolved problem of determining how large the permanent of a positive semi-definite matrix can be, given the eigenvalues, we note that a necessary condition for A to be a permanent maximizing matrix is that A commute with its permanental adjoint.