电感耦合等离子体原子发射光谱法测定硅铝铁合金中多种元素的优化研究

应用电感耦合等离子体原子发射光谱 (ICP AES)法 ,对硅铝铁合金中的Al,Fe ,Ca,Cr,Mn ,Ni,Si和Ti元素进行了测定。研究了ICP AES的操作条件和溶样方法 ,确定了适宜的实验条件 ,如对仪器参数和共存元素对信号的影响进行了研究。将实验条件优化后 ,使用该方法测定硅铝铁合金中多种元素 ,标准钢样测定结果与推荐值相符。对各种元素的检出限分别为Al(0 0 2 9μg·mL- 1 ) ,Fe(0 0 0 4 μg·mL- 1 ) ,Ca(0 0 0 75 μg·mL- 1 ) ,Cr(0 0 0 15 μg·mL- 1 ) ,Mn(0 0 0 0 9μg·mL- 1 ) ,Ni(0 0 0 2 7μg·mL- 1 ) ,Si(0 0 4 5 μg·mL- 1 )和Ti(0 0 0 3μg·mL- 1 )。对所测元素 ,测定结果的相对标准偏差 (n =6 )在 0 3%～ 1 8%之间 ,加入标准溶液的回收率在96 7%～ 10 2 9%范围。测定合金样品中高含量硅的结果与标准化学 (重量 )法的结果也相符。该方法的特点是数据可靠 ,简便可行和易于推广。     

非线性含磁芯线圈的PSpice模拟

 将感应加速腔的磁芯回路视为一段单匝的非线性电感线圈,利用PSpice的一些通用元器件组成的子电路对含有磁芯的非线性线圈进行模拟，使其具有饱和、磁滞及频率损耗等非线性特征。通过一些直观的参数设置，可使线圈模型适用于不同的频率范围。介绍了利用线圈模型对直线感应加速器加速组元系统的模拟，得到了与实验相符合的结果。     

Design of a reentrant double staggered ladder circuit for V-band coupled-cavity traveling-wave tube

The reentrant double staggered ladder slow-wave structure is employed in a high-power V-band coupled-cavity traveling-wave tube. This structure has a wide bandwidth, a moderate interaction impedance, and excellent thermal dissipation properties, besides the easy fabrication. A well-matched waveguide coupler is proposed for the structure. Combining the design of attenuators, a full-scale three-dimensional circuit model for the V-band coupled-cavity traveling-wave tube is constructed. The electromagnetic characteristics and the beam--wave interaction of this structure are investigated. The beam current is set to be 100 mA, and the cathode voltage is tuned from 16.8 kV to 15.8 kV. The calculation results show that this tube can produce a saturated average output power over 100 W with an instantaneous bandwidth greater than 1.25 GHz in the frequency ranging from 58 GHz to 62 GHz. The corresponding gain and electronic efficiency can reach over 32 dB and 6.5%, respectively.     

β-delayed neutron decay of 21N

The β-delayed neutron and γ spectra of neutron-rich nucleus ²¹N using β-γ and β-n coincidence measurements were presented in this paper. Thirteen new neutron groups ranging from 0.28 MeV to 4.98 MeV and with a total branching ratio 88.7±4.2% were observed. One γ transition among the excited states of ²¹O, and four γ transitions among the excited states of ²⁰O were identified in the β decay chain of ²¹N. The ungated half-life of 83.8±2.1 ms was also determined for ²¹N.     

柔性有机电致发光器件导电基板的工艺性能

在聚对苯二甲酸乙二醇酯(PET)柔性衬底上采用直流磁控溅射技术制备了氧化铟锡(ITO)透明导电薄膜,研究了衬底温度、溅射功率和溅射压强等工艺条件对薄膜光电性能的影响,并利用原子力显微镜(AFM)表征了衬底及ITO薄膜的表面形貌。结果表明,在PET衬底温度50℃、溅射功率100W和溅射压强2.66×10-1Pa的条件下,可以得到低方阻(50Ω/□)和高透过率(>90%)的透明导电薄膜。以此柔性ITO衬底为阳极,制备了结构为PET/ITO/NPB/Alq3/Mg∶Ag的柔性有机电致发光器件,在驱动电压为13V时,器件的发光亮度达到了2834cd/m2。     

采用7.5 μm中红外量子级联激光器的痕量甲烷气体检测仪

一种具有高稳定性和高敏感度的紧凑型仪器,能精确、实时、实地连续测量和显示环境空气中的痕量甲烷(CH₄)浓度。仪器采用了已集成热电制冷器激射波长为7.5μm的法布里-珀罗量子级联激光器(QCL)在室温脉冲工作模式下的最新技术,以覆盖CH₄位于ν₄附近基频特征吸收谱带。同时,采用高品质液氮制冷碲镉汞中红外探测器,配合全反射镀金椭球反射镜一同使用,在20 cm单路径开放式光路吸收气室环境下,确保被测甲烷气体浓度为200 μmol·mol-1的实验条件下保持稳定度高达5.2×10-3。此仪器所集成的软件算法通过时间鉴别电子技术实现对QCL控制,能够在无需校准的情况下,提供连续痕量甲烷气体检测。实验表明,仪器可以用于环境监测中的实地痕量气体测量,并且操作人员可以通过替换在不同波长下运行的QCL来测量其他气体。     

测定电磁波速度的一种简易方法

测定电磁波速度的一种简易方法黄永修，李金铭，李铁盘（河南教育学院）本文介绍了利用电磁波的滞后效应测定电磁波速度的方法，为在实验室内测定电磁波的速度提供了一种简单易行又较准确的方法．测定实验所用的仪器有信号源、示波器及传输线．测定电磁波在空气中的传播速...     

用计算机辅助测量液体的粘滞系数

主要说明用自制光电门配合计算机辅助测量液体粘滞系数的原理和方法,当小球挡住光电门的光路时,会使光敏管产生一个电脉冲,可以利用计算机声卡配合audition软件捕捉这个脉冲,从而实现小球下落时间的测量,提高实验的精确度。     

ICP-AES测定高含量锌、镉和铜

采用ICP-AES测定高含量锌、镉和铜,选择了最佳仪器工作条件和样品处理方法。在实验优选条件下,对铜镉渣中铜的含量为8%—12%;镉的含量为35%—38%;锌的含量为21%—23%进行了测定。回收率分别为铜99.8%—100.0%,镉98.3%—99.9%,锌99.3%—99.5%。     

Progress on accurate measurement of the Planck constant:Watt balance and counting atoms

The Planck constant h is one of the most significant constants in quantum physics.Recently,the precision measurement of the value of h has been a hot issue due to its important role for the establishment of both a new SI and a revised fundamental physical constant system.Up to date,two approaches,the watt balance and counting atoms,have been employed to determine the Planck constant at a level of several parts in 108.In this paper,the principle and progress on precision measurement of the Planck constant using watt balance and counting atoms at national metrology institutes are reviewed.Further improvement in determining the Planck constant and possible developments of a revised physical constant system in future are discussed.