Synthesis,Crystal Structure,and Magnetic Properties of a New Dinuclear Iron Complex with Schiff Base Ligand

A new dinuclear iron(Ⅲ) complex has been synthesized and structurally characterized by X-ray crystallography: [FeⅢ2(L)(C6H5COO)(SO4)(CH3OH)2]·CH3CN·CH3OH(1, H3 L = N,N'-bis(salicylidene)-1,3-diamino-2-propanol). Complex 1 belongs to orthorhombic space group Pna21 with a = 11.4400(8), b = 22.9705(2), c = 12.5712(9) , V = 3303.5(4) 3, Z = 4, F(000) = 1576, Dc = 1.531 g·cm–3, Mr = 761.36, μ = 1.007 mm–1, S = 1.014, the final R = 0.0505 and wR = 0.1018. The crystal packing is stabilized by intermolecular O–H···O hydrogen bonds, forming an extended one-dimensional chain structure. The temperature dependence of magnetic susceptibility measurement shows that antiferromagnetic interaction is propagated between the metal centers. Fit as dinuclear arrangement gave parameters of J = 19.7 cm-1, g = 1.89 and R2 = 0.9999.     

Negative compressibility property in hinging open-cell Kelvin structure

A new three-dimensional(3 D) cellular model based on hinging open-cell Kelvin structure is proposed for its negative compressibility property. It is shown that this model has adjustable compressibility and does exhibit negative compressibility for some certain conformations. And further study shows that the images of compressibility are symmetrical about the certain lines, which indicates that the mechanical properties of the model in the three axial directions are interchangeable and the model itself has a certain geometric symmetry. A comparison of the Kelvin model with its anisotropic form with the dodecahedron model shows that the Kelvin model has stronger negative compressibility property in all three directions.Therefore, a new and potential method to improve negative compressibility property can be derived by selecting the system type with lower symmetry and increasing the number of geometric parameters.     

Hydrothermal Synthesis and Structure of a Novel Coordination Polymer Co_3(tma)(pda)_2(H_2O)_3]n·nH_2O

1INTRODUCTION Recently,the design and preparation of coordina-tion polymers with new porous frameworks are of great interest due to their potential functionalities such as catalysis,gas absorption,separation and molecu-lar recognition.In designing1-D,2-D and3-D porous coordination polymers,the selection of appropriate ligands is crucial for determining the structure.The mixed-linker systems of both carboxylates and pyri-dyls have proved to be effective for the preparation of novel coordi…     

Crystal Structure of L-Quebrachitol

L-Quebrachitol (1) isolated from the root of Elaeagnus formosana Nakai (Elaeagnaceae) has not been reported before for any species of the genus of Elaeasnus. Its structure was established from spectral data and was completely characterized by single-crystal X-ray analysis. L-Quebrachitol crystallizes in the monoclinic system, space group P2₁, with cell parameters are a = 6.702(4), b = 7.207(4), c = 8.758(5) Å, β = 90.24(5)° and Z = 2.     

计算全息检测非球面干涉场的理论分析与实验结果

本文应用光学全息术及傅里叶光学的理论对计算全息图干涉检测非球面面形的光路及干涉场进行了理论分析,提出了其干涉场为不定域干涉的观点,并在实验中予以证实.     

Yb3+掺杂KY(WO4)2激光晶体生长、结构与光谱分析

采用顶部籽晶提拉法(TSSG)生长出Yb:KY(WO₄)₂(Yb:KYW)激光晶体.对预烧后的原料及晶体进行了XRD分析，结果表明，分别在920℃和600℃预烧8h后的熔质和助熔剂基本上形成一相，抑止了实验中的挥发问题；所生长的晶体为β-Yb:KYW，计算其晶格常数为a=1.063nm，b=1.034nm，c=0.755nm，β=130.75°.测得不同厚度样品的吸收光谱，结果表明样品在933nm和981nm有较强的吸收峰，计算出主峰981nm的吸收截面σ关键词： Yb:KYW TSSG法 晶体结构 光谱参数     

非晶态合金薄带与膜的巨磁电阻抗效应理论及计算

通过建立具有平面近横向各向异性场的非晶态合金薄带及膜的磁畴结构模型，利用线性化Maxwell方程组及Landau-Lifshitz方程，推出了在高频交变磁场及外加面内轴向直流磁场H_ex作用下的铁磁材料的与取向相关的磁导率表达式，得到了对方位角平均的相对磁导率及阻抗的计算式，导出了磁导率与张量磁化率分量间的关系，对材料磁导率的实部及虚部随H_ex的变化进行了计算，并给出了对应的磁谱图.建立的磁导率与外磁场的理论关系可将Panina及Kraus给出的理论结果统一起来. 关键词： 非晶态合金薄带及膜 取向相关磁导率 GMI效应理论与计算 近横向各向异性场     

部分相干电磁光束在湍流介质中传输的偏振变化

 从推广的惠更斯-菲涅尔原理出发，推导出了部分相干电磁光束的偏振态在湍流介质中传输的表达式。并以电磁高斯-谢尔模型(EGSM)光束为例，研究了湍流对电磁高斯-谢尔模型光束偏振态的影响。研究结果表明，对于轴上点，湍流介质的折射率结构常数越大，偏振度趋于最大值的速度越快，达到的最大值越小；光斑越大，偏振度达到最大值的位置离光源越远，在光斑增大的过程中，偏振度所达到的极大值会先增大后减小，最后保持与光源相同的偏振度不变。对于轴外点，一个固定的z，光的偏振度随着离轴距离的增大而逐渐下降，并最终等于零。折射率结构常数越大，偏振度随离轴距离的增大而下降得越缓慢；光斑越大，偏振度随离轴距离的增大下降得越快。     

机载稳瞄控制系统模型及仿真分析

瞄准线高精度稳定是机载光电稳瞄系统的主要指标和关键技术。根据四框架稳瞄系统的工作原理，以手动跟踪模式为主要研究对象，建立了稳瞄伺服控制系统模型。考虑到直升机扰动特点，对线扰动、角速率扰动、摩擦力矩、弹性力矩等各种扰动因素也建立相应的数学模型，同时在各种扰动因素作用下利用Matlab对机载高精度稳瞄系统的手动跟踪控制模式进行了仿真设计分析和理论研究，设计出适合的控制器。此模型在实际系统中获得验证，对稳瞄伺服控制系统的设计具有参考意义。     

匀速运动的电偶极子的电场和磁场分布

本文通过对电偶极子电磁势的分析和相对论下电磁场在不同惯性系中的协变分布，计算了作匀速直线运动的电偶极子的电场和磁场的空间分布．