火焰原子吸收光谱法测定厚朴花中金属元素含量

采用浓硝酸-高氯酸(5+1)消解处理样品,火焰原子吸收光谱法测定厚朴花中Ca、Mg、Fe、Zn、Cu和Mn6种金属元素含量。测定结果显示,厚朴花中含有丰富的金属元素。实验为探讨厚朴花中金属元素含量与药理关系提供了有用的数据。采用火焰原子吸收光谱法测定厚朴花中金属元素含量,操作简便、快速,结果准确。     

Highly sensitive giant magnetoimpedance in a solenoid containing FeCo-based ribbon

The highly sensitive giant magneto-impedance effect in a solenoid containing a magnetic core of Fe₃₆Co₃₆Nb₄Si_4.8B_19.2 (FeCo-based) ribbon under a weak magnetic field (WMF) is presented in this paper. The FeCo-based amorphous ribbon is prepared by single roller quenching and annealed with Joule heat in a flowing nitrogen atmosphere. The giant magnetoimpedance effect in solenoid (GMIES) profiles are measured with an HP4294A impedance analyzer. The result shows that the GMIES responds to the WMF sensitively (as high as 1580 %/A穖^-1). The high sensitivity can be obtained in a moderate narrow range of annealing current density (30-34 A/mm²) and closely depends on the driven current frequency. The highest sensitivity (1580 %/A穖^-1) is obtained when the FeCo-based amorphous ribbon is annealed at 32 A/mm² for 10 min and then driven with an alterning current (AC) at the frequency of 350 kHz. The highly sensitive GMIES under the WMF may result from the multiple magnetic-anisotropic structure, which is induced by the temperature gradient produced during Joule-heating the ribbon.     

Highly sensitive giant magnetoimpedance in a solenoid containing FeCo-based ribbon

The highly sensitive giant magneto-impedance effect in a solenoid containing a magnetic core of Fe36Co36Nb4Si4.8B19.2(FeCo-based) ribbon under a weak magnetic field(WMF) is presented in this paper.The FeCo-based amorphous ribbon is prepared by single roller quenching and annealed with Joule heat in a flowing nitrogen atmosphere.The giant magnetoimpedance effect in solenoid(GMIES) profiles are measured with an HP4294A impedance analyzer.The result shows that the GMIES responds to the WMF sensitively(as high as 1580 %/A·m 1).The high sensitivity can be obtained in a moderate narrow range of annealing current density(30-34 A/mm 2) and closely depends on the driven current frequency.The highest sensitivity(1580 %/A·m 1) is obtained when the FeCobased amorphous ribbon is annealed at 32 A/mm 2 for 10 min and then driven with an alterning current(AC) at the frequency of 350 kHz.The highly sensitive GMIES under the WMF may result from the multiple magnetic-anisotropic structure,which is induced by the temperature gradient produced during Joule-heating the ribbon.     

铁基纳米晶合金的介观阻抗率及应用

提出了铁基纳米晶合金介观阻抗率的物理概念,用Maxwell方程组求得其计算公式ρ=-μ{A}/{t}/Δ×H,该式表明铁基纳米晶合金的介观阻抗率与材料内部的介观磁场强度H、介观磁矢势A和介观磁导率μ有关,磁矢势A是由介观结构引起的量子力学效应,是由合金的微观结构决定的.这个理论很好地解释了铁基纳米晶粉末、粉芯 关键词： Fe基纳米晶合金 介观阻抗率     

油酸包裹对不同尺寸纳米α-Fe2O3晶体Morin相变影响的Mssbauer研究

用Mossbauer方法研究了冻油酸中的35nm与60nm均匀α－Fe2O3微晶的Morin相变温度，发现它比未包裹样品分别高了50K和24K。     

大学物理实验教学内容与方法改革探索

面对科学技术的飞速发展和现代社会对人才的要求,针对现阶段大学物理实验教学中普遍存在的问题,结合我校在大学物理实验教学改革的实际情况,提供了一系列大学物理实验教学改革的新思路和新方法。     

整系数多项式因式分解的一种新方法

利用整系数多项式与正有理数的对应 ,将多项式因式分解通过对真分数序列筛选的办法求得因式 ,给出了整系数多项式因式分解的一种新方法 .     

关于子式矩阵的行列式

讨论子式阵及伴随阵的行列式,得到了高阶伴随阵行列式的一般公式.我们的结果改进了文献中的相应结果.     

ACOUSTIC TRANSMISSION ATTENUATION CAUSED BY RANDOM SURFACE

Assuming that the rough surface is a stationary process with a normal distribution,the scat-tering of a plane acoustic wave by this surface is studied.The statistical mean of the reflection coef-ficient and its relation to the correlation radius of the random surface have been discussed.By in-troducing the concept of"the equivalent reflecting plane",a general formula for a field with apoint source in a stratified medium which has a random surface is derived.This demonstrates an easysolution to the additional attenuation coefficient under various sea conditions.The additional attenua-tion coefficients of the normal modes in the surface duct are given in detail.