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161.
162.
For two periods of quantum-cascade laser structures, we propose a system of closed balance equations that make it possible
to calculate the occupancy of the energy levels, the quasi-Fermi levels, and also the injection current density taking into
account different charge carrier scattering mechanisms.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 6, pp. 801–804, November–December, 2007. 相似文献
163.
164.
Xianqiao Liu Michael D. Kaminski Judy S. Riffle Haitao Chen Michael Torno Martha R. Finck LaToyia Taylor Axel J. Rosengart 《Journal of magnetism and magnetic materials》2007
This paper describes a single emulsion-solvent evaporation protocol to prepare PEGylated biodegradable/biocompatible magnetic carriers by utilizing hydrophobic magnetite and a mixture of poly(D,L lactide-co-glycolide) (PLGA) and poly(lactic acid-block-polyethylene glycol) (PLA-PEG) (26:1 by mass) polymers. We characterized the magnetic microspheres in terms of morphology, composite microstructure, size and size distribution, and magnetic properties. Results show that the preparation produces magnetic microspheres with a good spherical morphology, small size (mean diameter of 1.2–1.5 μm) by means of large size distributions, and magnetizations up to 20–30 emu/g of microspheres. 相似文献
165.
Haitao Chen Michael D. Kaminski Armin D. Ebner James A. Ritter Axel J. Rosengart 《Journal of magnetism and magnetic materials》2007
A technology that could physically remove substances from the blood such as biological, chemical, or radiological toxins could dramatically improve treatment of disease. One method in development proposes to use magnetic-polymer spheres to selectively bind toxins and remove them by magnetic filtration. Although magnetic filtration is a developed technology, the clinical boundary conditions described here require a new filter design. We investigated the removal of toxin-bound magnetic carriers from the blood stream using 2-D FEMLAB simulations. The magnetic separator consisted of a permanent magnet with parallel ferromagnetic prisms on the faces and in contact with a straight tube carrying the magnetic-polymer spheres in suspension. We varied the following parameters: blood flow velocity, the size, and number of ferromagnetic prisms, and the ferromagnetic material in both prisms and magnets. The capture efficiency reached maximum values when the depth of the prisms equaled the diameter of the tubing and the saturation magnetization of the prism material equaled twice that of the magnet. With this design a piece of 2 mm (diameter) tube carrying the fluid resulted in 95% capture of 2.0 μm magnetic-polymer spheres at 10 cm/s flow velocity. 相似文献
166.
167.
为探索激光诱导时间分辨荧光光谱技术应用于海洋悬浮溢油原位探测的可行性,对来自胜利油田六个不同井区不同密度的原油样品的时间分辨荧光光谱进行了探测分析。结果发现,各原油样品荧光发射的持续时间基本相同,从ICCD中数字延时发生器(DDG)的输入延时52 ns开始,到输入延时82 ns左右结束,各原油样品的荧光峰强度随时间变化曲线的半高宽约10 ns;不同原油样品的最强荧光峰位及其衰减寿命不尽相同,并且与样品密度有一定相关性,密度相近的原油具有相近的最强荧光峰位和相似的荧光寿命。对比六种原油样品的时间分辨荧光光谱发现,在荧光增强时,原油荧光光谱峰位不变,当荧光从最大强度开始衰减时,六种原油样品的荧光光谱峰位均出现了不同程度(17~30 nm)的红移现象,这一定程度上反映出原油中各荧光组分的荧光衰减速率存在差异,或者存在荧光组分之间的能量传递。所观测到的原油密度相关的时间分辨光谱信息和荧光峰红移现象可望成为水下悬浮溢油识别的有效特征之一。 相似文献
168.
M. Daum P. FierlingerB. Franke P. GeltenbortL. Goeltl E. GutsmiedlJ. Karch G. KesslerK. Kirch H.-C. KochA. Kraft T. LauerB. Lauss E. PierreG. Pignol D. ReggianiP. Schmidt-Wellenburg Yu. SobolevT. Zechlau G. Zsigmond 《Physics letters. [Part B]》2011,704(5):456-460
Ultracold neutrons were stored in a volume, using a magnetic dipole field shutter. Radial confinement was provided by material walls. Low-field seeking neutrons were axially confined above the magnetic field. High-field seeking neutrons are trapped inside the magnetic field. They can systematically shift the measured neutron lifetime to lower values in experiments with magnetic confinement. 相似文献
169.
基于光频调节的干涉型光纤水听器相位补偿检测方法 总被引:5,自引:0,他引:5
提出了一种基于光源频率调节的干涉型光纤水听器主动相位补偿的信号检测方法。详细介绍了该方法的基本检测原理,对信号解调误差进行了理论分析与仿真。为了验证该方法的可行性,搭建了实验系统,并编写了实时的信号采集、处理程序,对某一干涉型光纤水听器的声压灵敏度进行了测试。在频带20 Hz-1.3 kHz上,平均声压灵敏度为-162.2 dB(0 dB=1 rad/μPa),波动小于±0.8 dB,与采用相位载波调制解调方法测量的结果基本吻合。实验结果证明该方法是有效的。由于传感部分不含有源器件,便于实现全光纤化,且解调算法简单、检测频带宽,该方法能被广泛应用到各种干涉型光纤传感器的信号检测当中。 相似文献
170.
This paper calculates the lifetime of resonant state and
transmission probability of a single electron tunnelling in a
spherical quantum dot (SQD) structure by using the transfer matrix
technique. In the SQD, the electron is confined both transversally
and longitudinally, the motion in the transverse and longitudinal
directions is separated by using the adiabatic approximation theory.
Meanwhile, the energy levels of the former are
considered as the
effective confining potential. The numerical calculations are carried out
for the SQD consisting of GaAs/InAs material. The obtained results show that the
bigger radius of the quantum dot not only leads significantly to the shifts
of resonant peaks toward the low-energy region, but also causes the
lengthening of the lifetime of resonant state. The lifetime of resonant
state can be calculated from the uncertainty principle between the energy
half width and lifetime. 相似文献