Zero—field—cooled and field—cooled magnetizations and magnetic susceptibility of itinerant ferromagnet SrRuO3

Zero-field-cooled(ZFC) magnetization,field-cooled(FC) magnetization,ac magnetic susceptibility and major hysteresis loops of itinerant ferromagnet SrRuO3 have been measured at magnetic ordering temperatures ranging from 5 to 160K.An empirical model is proposed to calculate the measured ZFC magnetization.The result indicates that the calculated ZFC magnetization compares well with the measured one.Based on the generalized Preisach model.both the ZFC and FC curves are reproduced by numerical simulations.The critical temperature and critical exponents are determined by measuring the ac magnetic susceptibility in different bias magnetic fields at temperatures in the vicinity of the point of phase transition.     

态|Ψ(3)〉q中广义磁场的不等幂次高次振幅压缩

利用多模压缩态理论,研究了一种新型的三态叠加多模叠加态光场|Ψ⁽³⁾〉_q中广义磁场分量(即第一正交相位分量)的不等幂次高次振幅压缩特性.结果表明:态|Ψ⁽³⁾〉_q是一种典型的三态叠加多模非经典光场,其广义磁场分量在一定条件下可呈现出周期性变化的、偶数次的不等幂次高次振幅压缩效应.     

全固态多波长飞秒脉冲激光系统

利用棱镜对引进频谱空间啁啾来补偿飞秒脉冲激光二次谐波产生中的相位失配,提高了倍频效率建立了一套全固态、多波长(1065nm, 532nm,823.1nm, 402nm)飞秒脉冲激光系统自制的Nd:YVO4激光器输出532nm绿光激光,最高平均功率可达5.6W当用2.5W绿光激光泵浦时,从自制的钛宝石激光器及经BBO倍频可分别输出中心波长为823.1nm和402nm,平均功率300mW和73mW,谱宽32.3nm和5.1nm,脉宽22fs和33.3fs、重复率108MHz的近红外和蓝光激光整个系统具有结构紧凑、倍频效率高、运行稳定的特点.     

丙氨酸咪唑钐的三维荧光激发和发射光谱

测量了新制丙氨酸咪唑钐水溶液的三维荧光激发和发射光谱,分析了在不同波长激发光作用下的荧光特征,与配体咪唑、α-丙氨酸及氯化钐的荧光谱进行了比较,讨论了模型化合物上转换荧光中的双光子和多光子加合现象并发现在10^-2-10^-4 mol/L 浓度范围内荧光强度与溶液浓度呈正相关.     

微通道板固定图案噪声及测试研究

叙述微通道板的噪声,着重介绍微通道板固定图案噪声及其简便新颖而又实用的一种测试方法,给出测试结果并进行分析。     

Dihydrogen bond in C2H4− n Cl n ··· NaH (n = 0, 1, 2, 3) complexes: ab initio,AIM and NBO studies

The dihydrogen-bonded complexes of ethylene and its chlorine derivatives with sodium hydride have been systematically investigated at the MP2/6-311++G(d,p) level. The studied complexes are divided into three groups (including Linear, Five- and Six-membered cyclic structures) based on the optimized structures. The structural, energetic and topological parameters are presented and analysed in terms of their possible correlation with the interaction energies and the intermolecular H?···?H distances. The nature of the electrostatic interaction in this type of dihydrogen bond has also been unveiled by means of atoms in molecules (AIM) and natural bond orbital (NBO) analysis. The effect of ring structure on the dihydrogen bonding systems has been considered by comparing with the corresponding linear structure. NBO analysis suggests that the electron density transfer (EDT) in cyclic structures have dual-channel character.     

可聚合型溶致液晶单体3,4,5-三(11-十一烷氧丙烯酰氧基)苯甲酸钠的自组装及紫外光固化性能

以3,4,5-三羟基苯甲酸为原料,依次经过酯化、醚化、酰氯化和钠盐化四步反应合成一种可聚合型溶致液晶单体3,4,5-三(11-十一烷氧丙烯酰氧基)苯甲酸钠,并对其结构进行了傅里叶变换红外与1H核磁表征. 在室温下研究了该单体在水中的自组装行为,组装体结构通过偏光显微镜与X射线衍射仪进行表征. 研究表明,单体与水比例为80:20时可自组装为层状(La)相,92:8时组装为反六方(H_II)相,这与临界堆积参数的理论计算相吻合,表明单体浓度是影响组装体结构的重要因素. 在组装的基础上研究了含不同光引发剂的溶致液晶体系的双键转化率及固化后组装体结构的保留. 经实时红外表征及溶胶-凝胶法的验证发现在光强为30 mW/cm²的365 nm下曝光30 min,含引发剂Darocur2959的溶致液晶体系双键转化率可达78%. 聚合之后La相与H_II相的纳米结构都得到了保留.     

离子速度成像技术研究2-溴戊烷的光解离动力学

运用离子速度成像技术研究了2-溴戊烷分子在～234 nm处的光解离动力学. 通过分析光解产物Br(²P_3/2)(简称Br)和Br(²P_1/2) (简称Br*)的速度影像,分别得到其速度分布和角度分布. Br和Br*的速度分布可以用两个高斯分布拟合,分别对应于2-溴戊烷在～234 nm处两个独立的光解离反应通道. 高能的高斯分量对应于C-Br伸缩振动模式的直接解离,低能的高斯分量对应于弯曲振动和C-Br伸缩振动耦合所导致的解离. 确定出光解离产物Br的相对量子产率为0.892,结合Br和Br*碎片的各项异性参数和溴原子的相对量子产率,讨论了³Q₀、³Q₁和¹Q₁激发态分别对产物Br和Br*的贡献. 通过对比溴代戊烷4种同分异构体光解离过程的差异,讨论了分子烷基分支化对光解机理的影响.     

An improved least square channel estimation algorithm for coherent optical OFDM system

This paper presents an improved processing added to conventional least square (LS) channel estimation to modify its performance for coherent optical orthogonal frequency division multiplexing (CO-OFDM) system. By testing selected limitation factors of the existing algorithms, the influence of our improved algorithm to the performance of CO-OFDM system were studied and compared with other published algorithms. The simulation results of the study demonstrated that the proposed approaches achieved better channel estimation performance and are considered as a more appropriate alternative for CO-OFDM system with the tradeoff between complexity and performance.