Synthesis,characterization and magnetic properties of some LnBO3 (Ln ≡ Pr,Sm, Eu AND Yb) compounds

The aim of this work is to complete a study previously initiated by us on the synthesis, characterization and magnetic properties of the lanthanide orthoborates. The different LnBO₃ compounds were obtained by mixing metal hydroxides Ln(OH)₃ and orthoboric acid B(OH)₃ in stoichiometric amounts at low temperatures between 873 and 973 K and at pressures of between 10⁻⁴ and 10⁻⁵ mmHg. This method had been previously successfully applied to the isolation of the other lanthanide orthoborates. The characterization of these materials was carried out by X-ray powder diffraction and IR spectrometry. The magnetic susceptibilities of these compounds were measured in the temperature range 4.2–300 K. The susceptibilities of PrBO₃ and YbBO₃ obey the Curie-Weiss law from 300 to 30 K, but deviations from this law occur at lower temperatures. The temperature dependences of the magnetic susceptibilities of SmBO₃ and EuBO₃ were also studied.     

Ring-closing metathesis protocol for a diastereocontrolled preparation of the C28–C34 segment of FK-506

A new synthesis of the C₂₈–C₃₄ segment of FK-506 has been developed using a chiral building block having a 6,8-dioxabicyclo[3.2.1]octane framework by employing a ring-closing metathesis reaction as the key step.     

两种对称型稀疏孔径系统的成像研究

提出了复合三子镜稀疏孔径结构,它由九个子镜组成,每三个子镜组成一个次级光瞳,三个次级光瞳组成一个主光瞳,其结构是对称的冗余结构.研究了三臂和复合三子镜两种对称型结构稀疏孔径系统,比较复合三子镜和三臂结构的特点与调制传递函数,对不同填充因子的两种结构的稀疏孔径模拟成像和维纳滤波,并进行像质评价,同时和非冗余的Golay6结构进行比较.结果表明：复合三子镜稀疏孔径系统在结构分布、成像质量等方面优于三臂对称结构稀疏孔径系统,对称型稀疏孔径系统在结构排列上具有对称易装调的优点.     

The miniemulsification process — different form of spontaneous emulsification

The miniemulsification process involves the use of low concentrations of mixed emulsifier combinations of an ionic surfactant (e.g. sodium lauryl sulfate) and a cosurfactant (e.g. long-chain fatty alcohol — cetyl alcohol). The product is an oil-in-water miniemulsion with an average droplet diameter of 100–400 nm, and excellent shelf stability. The dominant presence of liquid crystals in the aqueous mixed emulsifier system, under conditions of the miniemulsification process, was confirmed by consideration of phase diagrams, conductivity and birefringence studies. Unexpectedly, interfacial tension studies showed relatively high values of 5–15 dyn cm⁻¹. In spite of these high interfacial tensions, spontaneous emulsification was found at the oil-water interface, contrary to what is known in the field. Adsorption and electrophoretic mobility studies suggested that the miniemulsification process takes place by unidirectional swelling of the lamellar bilayers in the aqueous mixed emulsifier liquid crystal system as a result of absorption of oil, followed by subdivision of these entities. The stability of miniemulsions formed by this process is influenced by a steric component in the mixed emulsifier complex adsorbed at the oil-water interface.     

Marine zone systems of higher productivity and purification using distributed energies

The present research focused on re-circulation and conversion of substance and energies for creating water environments of higher productivity and purification from the oceanic carbon and nitrogen cycle point of view. The application of distributed energies and integrated systems through the autonomous dispersion control of the environment is able to display the increase of the functions of living things and create the harmonized re-circulation of production and purification. As Japan is an island country, wave energy pumps and air-mixed jet pumps have been invented as distributed energy prime movers for these circulation systems. This paper summarizes our research and development programs and describes some current results of sea trials with prototypes.     

一种联咔唑类双极性蓝色磷光主体材料的合成及性能

以联咔唑作为电子给体,二苯基磷氧基团作为电子受体,设计合成了双极性蓝色磷光主体材料6,6'-二(二苯基磷氧基)-9,9'-二己基-3,3'-联咔唑(DPDBC)。通过紫外-可见(UV-Vis)、荧光、低温磷光、循环伏安法、热重分析(TGA)、差热分析(DSC)和密度泛函理论(DFT)对其性能及轨道能级等进行了研究。结果表明,化合物DPDBC在CH₂Cl₂稀溶液中有两个吸收峰,最大吸收峰位于306 nm;它的荧光发射峰位于420 nm,属于深蓝色荧光;DPDBC的低温磷光光谱的第一发射峰位于447 nm,其三重态能级为2.77 eV,与蓝色磷光客体材料FIrpic (2.62 eV)的能级相匹配;测定其循环伏安特性曲线,计算得到它的HOMO能级为-5.48 eV,与阳极ITO的功函(-4.5~-5.0 eV)相匹配,LUMO能级为-2.36 eV,接近于电子传输材料PBD(-2.82 eV),表明它具有双极性能;TGA显示其分解温度为410℃,表明热稳定性能优良,DSC显示其T_g温度为140℃,表明其具有无定形态结构及良好的成膜性能。因此,DPDBC是一种集双极性传输性能于一体,同时又具有优良热稳定性能的潜在蓝色磷光主体材料。     

Li3V2(PO4)3/C和Li2.5Na0.5V2(PO4)3/C的结构和电化学性能的比较研究

采用溶胶-凝胶法合成了锂离子正极材料Li3V2(PO4)3/C(LVP/C)及Li2.5Na0.5V2(PO4)3/C,并用XRD、循环伏安及交流阻抗等方法,研究了大量Na+掺杂对材料结构和电化学性能影响。结果表明,大量钠离子的掺杂会使LVP结构由单斜向菱方转变。掺杂化合物Li2.5Na0.5V2(PO4)3/C在0.5 C充电1 C放电时,首次放电容量为118 mAh.g-1,50次循环后容量保持率为92.4%,并发现与单斜LVP存在多个放电平台不同,Li2.5Na0.5V2(PO4)3/C仅在3.7 V处有一个放电平台。     

干涉测量圆柱外表面的误差分析

使用一个特殊圆台面反射镜,在Fizeau（菲索）干涉仪系统中,可实现对圆柱外表面粗糙度的一次性测量。但反射镜与待检测圆柱的空间相对位置很难精准确定,因而会引入测量失调误差,影响测量结果的精度。为了便于剔除误差,要对误差的类型以及产生原因做具体分析。研究光线传播轨迹并建立数学模型,在圆柱坐标系下求解得到偏移失调误差、旋转失调误差、加工角度误差与测量光程差的关系式。使用Matlab软件仿真,绘制出3种失调误差对应的干涉条纹。分析引入误差的干涉条纹,对比实验测量结果,减小误差对测量结果的影响,得到圆柱外表面的形貌信息。     

High-resolution infrared spectrum of the fundamental band of LiCl at a temperature of 830°C

High-resolution Fourier transform spectra of ⁶LiCl and ⁷LiCl have been recorded at 830°C. A total of 2522 lines have been measured at 0.006 cm⁻¹ resolution in the 500- to 730-cm⁻¹ region. The data for all four isotopic species have been fit with a standard deviation of 0.00027 cm⁻¹ using 19 isotopically invariant rovibrational constants including five Δ_ij correction terms to the usual Dunham Y_ij terms. Comparison is made with the constants derived from a direct fit of the observed transitions to a Dunham potential function with only 13 coefficients including for Δ correction terms. The gas phase band center for the v = 1–0 transition of ⁷Li³⁵Cl is 634.0753(7) cm⁻¹.     

Synthesis and Ultrafast Broadband Optical Limiting Properties of a Two-Branched Twistacene

A novel two-branched twistacene (PyDN) has been designed and synthesized for application on ultrafast optical limiting. This twistacene exhibits excellent two photon absorption and two photon absorption-induced excited singlet state absorption, which was systematically investigated with a femtosecond Z-scan experiment, transient absorption spectrum, and two-photon excited fluorescence experiments. The admirable two photon absorption is attributed to the high degree of π electron delocalization in twistacene which is caused by introduction of two strong donors. The excited singlet state absorption cooperates with two-photon absorption to provide an excellent ultrafast optical limiting behavior with high linear transmittance, where the thresholds are 2.3–5.3 mJ/cm² in the spectral region of 532–800 nm of femtosecond laser and 133 mJ/cm² for picosecond pulse at 532 nm. These thresholds are lower than that of most of the optical limiters reported previously, which indicates PyDN is a promising candidate for ultrafast optical limiting.