Characterizing a proton beam with two different methods in beam halo experiments

In beam halo experiments, it is very important to correctly characterize the RFQ output proton beam. In order to simulate the beam dynamics properly, we must first know the correct initial beam parameters. We have used two different methods, quadrupole scans and multi-wire scanners to determine the transverse phase-space properties of the proton beam. The experimental data were analyzed by fitting to the 3-D nonlinear simulation code IMPACT. For the quadrupole scan method, we found that the RMS beam radius and the measured beam-core profiles agreed very well with the simulations. For the multi-wire scanner method, we choose the case of a matched beam. By fitting the IMPACT simulation results to the measured data, we obtained the Courant-Snyder parameters and the emittance of the beam. The difference between the two methods is about eight percent, which is acceptable in our experiments.     

二硫代草酸根桥联的双核镍(Ⅱ)配合物研究

Three binuclear Nickel(Ⅱ) complexes were synthesized, bridged with dithiooxalate, Ni₂(Bpy)₃(Dto)₂(H₂O)₃(1), Ni₂(Phen)₃(Dto)₂(H₂O)₃(2) and Ni₂(Me₂Bpy)₃(Dto)₂(H₂O)₂ (3) (Bpy=2,2′-Bipyridine, Phen=1,10-phenanthroline, Me₂Bpy=4,4′-dimethyl-2,2′-bipyridine, Dto^2-=Dithiooxalate), and characterized by elemental analyses, IR, UV-Visible spectra, conductance. The variable temperature magnetic susceptibilities for the complexes were measured in the range of temperature between 1.5 K and 298 K. Experimental data of magnetic susceptibility were successfully fit to theoretical value based on the spin Hamiltonian operator：(?), S₁=S₂=1, giving the magnetic exchange parameters of 2J=-52.8 cm^-1. This result indicates the presence of a strong antiferromagnetic spin exchange interaction between the Ni(Ⅱ) ions. The magnetic exchange parameters of the binuclear Nickel(Ⅱ) complexes bridged with dithiooxalate is larger than that of the binuclear Nickel(Ⅱ) complexes bridged with oxalate. Dithiooxalate is more effective to transfer antiferromagnetic spin exchange interaction between the Ni(Ⅱ) ions than oxalate.     

2, 6─二甲酸─4─取代苯酚双缩苯甲酰肼双核铜(Ⅱ)配合物的合成与磁性

本文合成并表征了两个新的双核铜（Ⅱ）配合物：［Ｃｕ２（Ｌ）（μ－Ｃｌ）Ｃｌ２］，配体Ｌ为２，６－二甲酰－４－基苯酚双缩苯甲酰肼，取代基分别为氯（Ｌ１）和叔丁基（Ｌ２）。配合物具有相同的组成和配位构型。变温磁化率测定结果表明，由于取代基不同，其磁交换参数分别为－４６．２ｃｍ＾－１（Ｌ１）和－５７．６ｃｍ＾－１（Ｌ２）。     

氰根桥连的锰钴五核配合物的合成与晶体结构

Reaction of [Mn(bpm)₂]²⁺ with K₃[Co(CN)₅(NO)] produces a cyano-bridged bimetallic compound,{[Mn(bpm)₂]_1.5[Co(CN)₅(NO)]}·2H₂O (1), (bpm=bis(1-pyrazol)methane). Compound 1 crystallizes in the tetragonal space group P4₃2₁2 with a=1.305 08(8) nm, b=1.305 08(8) nm, c=4.386 7(5) nm, V=7.471 5(10) nm³, and Z=8. Complex 1 exhibited a structure of a pentanuclear cluster. The Mn²⁺ ions each are surrounded by bpm ligands, forming the [Mn(bpm)₂]²⁺ cation fragment. Three cation fragments are connected to the two anion fragments, [Co(CN)₅(NO)]^3-, by cyanide bridges. The five metal ions form a trigonal bipyramidal structure, where the Mn²⁺ ions are situated in the equatorial plane and the Co²⁺ ions are on both sides of the plane. As a semirigid ligand, bpm is more flexible than rigid 2,2′-bipydine, and it results in the two different configurations in the [Mn(bpm)₂]²⁺ cation fragment. CCDC: 635764.     

对化学的挑战——分子铁磁体的设计

寻求常温下的分子铁磁体是自然界向化学家挑战的一个热点课题.本文介绍了迄今美、俄、法、日等国家在该领域已取得的最新成果及已采用的几种设计与合成途径,即有机方法、金属有机方法、金属—自由基方法和无机方法等.其中通过无机方法制得的铜锰交替链状配合物的铁磁相转变温度(T_c)达到30K,这是目前通过各种方法制得的T_c最高的分子铁磁体。     

N,N'-双(2-吡啶乙基)二硫代草酰胺根桥联的三核铜(Ⅱ)配合物的合成及性质

0引言多原子桥联配体的多核配合物中,顺磁离子间磁偶合作用的研究对阐明磁性和结构的关系以及设计新型分子基磁性材料具有重要的理论意义。草酸根及草酰胺根桥联的多核配合物得到了较为广泛和深入的研究[1~5]。硫原子取代两个氧原子后,形成二硫代草酸根及二硫代草酰胺根,由于硫     

一维梯子状配位聚合物[Na3Er(2，6-PDA)3]·11.5H2O的合成与晶体结构

A novel 1D Ladder-like coordination polymer [Na₃Er(2，6-PDA)₃]·11.5H₂O (2,6-H₂PDA is pyridine-2,6-dicarboxylic acid) has been synthesized and the crystal structure was determined by X-ray diffraction. The crystal structure of the complex belongs to Monoclinic system with space group P2₁/c, a=0.969 7(3) nm, b=1.914 6(6) nm, c=1.8031(6) nm, β=91.524(5)°, V=3.346 6(18) mm³, Z=4, D_c=1.863g·cm^-3, μ=2.645 mm^-1. The coordination geometry configuration of Er³⁺ center is tricapped trigonal prism. The structures of the title compound exhibit a novel 1D Ladder-like chain.     

1，4-二氮杂二环[2.2.2]辛烷-1，4-二乙酸配合物的合成、结构与磁性

合成了{[M(L)₂(H₂O)₂](ClO₄)₂·4H₂O}_n(M=Cu 1,Co 2;L=1,4-二氮杂二环[2.2.2]辛烷-1,4-二乙酸),并进行了元素分析、红外、热重、变温磁化率等表征。单晶结构表明这2个配合物属于单斜晶系,P2₁/c空间群。Cu(Ⅱ)和     

求解约束优化问题的记忆梯度Goldstein-Lavintin-Polyak投影算法

给求解无约束规划问题的记忆梯度算法中的参数一个特殊取法,得到目标函数的记忆梯度G o ldste in-L av in tin-Po lyak投影下降方向,从而对凸约束的非线性规划问题构造了一个记忆梯度G o ldste in-L av in tin-Po lyak投影算法,并在一维精确步长搜索和去掉迭代点列有界的条件下,分析了算法的全局收敛性,得到了一些较为深刻的收敛性结果.同时给出了结合FR,PR,HS共轭梯度算法的记忆梯度G o ldste in-L av in tin-Po lyak投影算法,从而将经典共轭梯度算法推广用于求解凸约束的非线性规划问题.数值例子表明新算法比梯度投影算法有效.     

平抛运动教学设计

教学对象：工科类中专生。教学地点：多媒体教室。教学辅助物：平抛竖落仪 磁铁铁 球多 媒体课件。