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931.
F.J. Hartmann 《Hyperfine Interactions》1999,119(1-4):175-184
The experiments on metastable antiprotonic helium atoms are reviewed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
932.
LUO Wen XU Wang PAN Qiang-yan XU Yi FAN Gong-tao FAN Guang-wei YANG Li-feng LI Yong-jiang YAN Zhe XU Ben-ji 《原子核物理评论》2009,26(Z1)
A simple X-ray spectrometer and a PC-Based Data Acquisition System(DAS) have been developed newly in Shanghai Institute of Applied Physics(SINAP),Chinese Academy of Sciences (CAS) for the measurement of the X-ray source generated using laser Compton scattering.The system consists of liquid nitrogen cooled high resolution Si(Li) detector,electronics and a DAQ.The Si(Li) detector was designed and made by Center of Advanced Instruments in SINAP,CAS,it allows us to measure X-rays with the energy up to 60 keV and the energy resolution(FWHM) of 184 eV at 5.9 keV.We measured the system uncertainty was 0.2 eV and time drifting of detector was 0.05% both at 5.9 keV.The DAQ was based on Object-Oriented software LabVIEW 7.1,it has data on-line analysis and original data saved functions. 相似文献
933.
With the monotonic increasing demand of the higher bandwidth for the next generation wireless communication system, the extension of the operating frequency of the communication system to the millimeter/Terahertz wave regime of the electromagnetic spectrum where several low-attenuation windows exist is inevitable. However, before the commercial implementation of the wireless communication in these low-attenuation windows, there are various obstacles which need to be addressed by the scientists and researchers. The atmospheric path loss is the main obstacle to the full-fledged implementation of the terahertz wireless communication. The remedy to this problem is the use of high-power sources, efficient detectors and high gain antenna systems. This paper reviews these technical issues with the special attention to the planar antennas which might contribute to the compact, inexpensive, and low profile future terahertz wireless communication system design. 相似文献
934.
The fluorescence mode confocal laser scanning microscopy (CLSM) is introduced as an alternative method to investigate the
bulk structure of poly(vinyl alcohol) (PVA) hydrogel. Investigations of the bulk structure of hydrogel samples, prepared by
freezing and controlled thawing of aqueous PVA solutions followed by fluorochrome conjugation, were possible in the native
state because with this technique water does not need to be removed prior to examination. This is of advantage to other methods,
such as scanning electron microscopy, requiring dehydration by critical-point drying or freeze-etching, because both may result
in a significant alteration of the gel structure. CLSM images of the hydrogel bulk structure were taken at several successive
intervals from the surface into the hydrogel (up to 60 μm) without freeze-fracturing or cutting the sample. Detailed morphological
characterization is achievable by superimposing series of images taken at successive intervals and by magnifying special regions
of interest. Images of hydrogel bulk structures revealed a continuous, three-dimensional network that originates from phase-separation
(spinodal decomposition) during the freezing period. The pore or mesh size in the cryogel increased, from about 2–7 μm, with
decreasing PVA concentration. The surface layer was only a few microns thick, and the bulk structure underneath showed neither
porosity gradients nor structural orientations.
Received: 29 April 2000/Accepted: 18 August 2000 相似文献
935.
Popescu C. Voicu I. Alexandrescu R. Morjan I. Dumitras D. Popescu M. Fatu D. 《Journal of Thermal Analysis and Calorimetry》1999,56(1):183-189
This paper reports on the synthesis of various iron oxides by the IR laser processing of different iron salts. X-ray diffraction
techniques were used to characterize the reaction products. Some differences in terms of crystallite size and isotropy between
these oxides and those obtained from the same salt by thermal means are described and explained.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
936.
Liang Liu Dujuan Zeng Xianlong Wei Qing Chen Xide Li 《Acta Mechanica Solida Sinica》2009,22(6):584-592
Two kinds of clamping in micro/nano scale experiments are investigated in this paper, one based on electron-beam-induced deposition, and the other on the van der Waals interaction. The clamping strength and mechanism are analyzed both theoretically and experimentally. The influence of relative humidity on the micro/nano clamping and the method of electrostatic clamping are discussed. The clamping strength and performance of different clamping methods are compared considering the size and material of the clamped objects, and the application environments. 相似文献
937.
938.
The proton magnetic resonance spectra of several 1,2,3,3-tetrasubstituted cyclopropane compounds obtained as intermediates in a new pyrethroid synthesis and containing double bond and carbonyl functions, have been studied in benzene and chloroform as solvents. 相似文献
939.
Lasers and amplifiers in a single fiber have been developed rapidly, especially for optical fiber communication and various sensors, in the recent years. However, remarkable progress and achievement have been made mainly in silica fiber doped with rare earth elements. In this paper, we report the progress on the development of the Yb3+-doped phosphate fiber laser. 相似文献
940.
Straightness Measurement Using Laser Diode and CCD Camera 总被引:4,自引:0,他引:4
HAO Qun ZHAO Yang LI Dacheng CAO Mang 《Chinese Journal of Lasers》1999,8(3):215-220
1IntroductionInmanufactureandasembleofmodernmachinesandinstruments,anindispensablerequirementisthecontrolofformandpositionero... 相似文献