陈岁元
,
刘常升
,
马利霞
,
谭勇
,
才庆魁
材料与冶金学报
doi:10.3969/j.issn.1671-6620.2005.03.012
在较低激光功率(40～170 W)和两种扫描速度(10mm/s,5mm/s)辐照条件下,研究了CO2激光辐照工艺对非晶Fe73.5Cu1Nb3S13.5B9合金晶化行为的影响.用穆斯堡尔谱(MS)技术对原始态和晶化后样品进行了结构分析.研究发现:非晶Fe73.5Cu1Nb3S13.5B9表面产生了少量晶化,晶化相为Fe-Si结构;晶化量在2.1%～3.57%内,随激光功率的增加而增加.当激光功率较低时,低扫描速度对晶化的促进作用大于激光功率的作用;但是,随激光功率增大,速度的影响变弱.表面微观硬度随激光功率的增加而增加.
关键词:
CO2激光
,
非晶Fe73.5Cu1Nb3Si13.5B9
,
晶化
,
穆斯堡尔谱
韩文静
,
阿古拉
,
赵丽佳
,
白音孟和
人工晶体学报
以1,4-丁二胺为溶剂合成两种硫属化合物(1,4-DABH2)2Sn2S6·(1,4-DAB)(1)和(1,4-DABH2) Sb4S7(2)(1,4-DAB =1,4-丁二胺),单晶X-射线衍射分析表明化合物1为单斜晶系,空间群为P21/c,a=1.0862(5) nm,b=1.3053(6) nm,c=1.0283(5) nm,β=101.20(2)°,V=1.4302(12) nm3,Z=2;化合物2为三斜晶系,空间群为P-1,a=0.6009(4) nm,b =0.8989(7) nm,c=1.6548(12) nm,α =89.774(12)°,β=86.481 (12)°,γ=84.495(12)°,V=0.8880(11)nm3,Z=2.化合物1由离散的[Sn2S6]2+、质子化的有机胺和未质子化有机胺组成.化合物2是由质子化的有机胺和双链的[Sb4S7]2-离子组成的二维层状化合物.紫外-可见漫反射光谱研究结果表明,化合物1和2的禁带宽度分别为1.80 eV和1.54 eV,均为半导体.
关键词:
溶剂热合成
,
锡/锑硫属化合物
,
晶体结构
,
表征
谭文一
,
胡飞
,
张锋刚
机械工程材料
用光学显微镜、显微硬度计、扫描电镜及三点弯曲疲劳试验机等研究了B级铸钢与Q450NQR1钢焊接接头的组织与性能.结果表明:其焊缝组织为细小树枝状铁素体+珠光体,B级铸钢侧热影响区近焊缝区有马氏体组织;焊缝硬度达240～295 HV,高于两侧母材的;B级铸钢侧热影响区硬度波动最大,硬度也最高,达370 HV;与焊态相比,焊趾处打磨可使接头疲劳强度提高12%,整体喷丸可提高15%;在循环载荷作用下,焊接接头多在焊根处起裂.
关键词:
B级铸钢
,
Q450NQR1钢
,
焊接接头
,
疲劳性能
Journal of Physical Chemistry A
The temperature dependence of magnetic susceptibility and sublattice magnetizations were calculated for a Heisenberg Hamiltonian of an S = 1 and S = 1/2 antiferromagnetic alternating spin chain by means of the many-body Green's function theory to show the possible occurrence of a ferrimagnetic phase transition for genuinely organic molecule-based magnets. The S = 1 site in the chain is composed of two S = 1/2 spins coupled by a finite ferromagnetic interaction. From the calculated results, it is found that the sublattice magnetization at low-spin S = 1/2 sites changes its sign from negative to positive with increasing temperature, giving rise to the spin alignments along the chain changing from anti ferromagnetic to ferromagnetic ones, which indicates that there is a magnetic phase transition occurring. Because of the weak intermolecular anti ferromagnetic interactions, the curves of the magnetic susceptibility multiplied by temperature (chi T) against temperature show a round peak at low temperatures, which is well consistent with recent experimental observations, and the ferrimagnetic phase transition could only be detected at an ultralow-temperature region and under very weak,external magnetic fields in practical organic materials. From the analysis of the sublattice magnetizations, it is uncovered that the appearance of the low-temperature peak in the curves of the chi T originates from the ferromagnetic spin alignments for all the spins along the chain, and the intermolecular antiferromagnetic interactions play a pivotal role in ferrimagnetic spin alignments of the magnetic systems. It is also found that the higher spatial symmetry of the intermolecular antiferromagnetic interactions have contributions to stabilize the ferrimagnetic ordering state in the molecule-based magnetic materials.
关键词:
nitrophenyl nitronyl nitroxide;simple classical pictures;numerical-calculations;composite molecules;magnetic-properties;building-blocks;ground-state;component;model;system
Journal of Applied Physics
Structural characteristics of Fe73.5Cu1Nb3Si13.5B9 soft magnetic alloys that were rapidly solidified and then annealed at various temperatures between 400 and 600-degrees-C have been studied. Variations of the Si content in the nanocrystalline alpha-Fe(Si) phase for the alloys with the annealing temperatures are determined. A maximum volume fraction, less than 70%, of the alpha-Fe(Si) phase is given by the Si-content results. The relationship between the structural characteristics and the magnetic properties for the alloys is discussed.
关键词:
ultrafine grain-structure
余庚华
,
仲嘉琪
,
王谨
,
詹明生
量子电子学报
doi:10.3969/j.issn.1007-5461.2012.03.001
Ba原子是光频标的候选者之一,对其进行有效的激光冷却与囚禁需要相关能级的寿命和跃迁几率的信息.Ba原子激发态6s6p3P1能级在激光冷却实验中很重要,通过Hanle效应实验测量了这一能级的寿命和自发辐射率,从理论和实验上研究了探测激光有限线宽和光强对Ba原子基态6s21S0与激发态6s6p3P1之间跃迁(波长791nm)Hanle效应荧光信号的影响.在考虑了激光线宽和光强因素后所得到的激发态6s6p3P1的能级寿命和自发辐射率与其他方法给出的结果符合很好.
关键词:
光谱学
,
能级寿命
,
Hanle效应
,
线宽
,
Ba原子
,
原子频标
