最新刊期
      卷 0 ， 期 0 ， 2020
      • LIU Tao XIE Yaning HU Tiandou
        Issue 6, (2004)
        摘要：The construction of 1W1B beamline and XAFS station at Beijing Synchrotron Radiation Laboratory has provided an additional tool and choice for users to do research work. To fit with a variety of demands from users, the controlling system of this facility has to be very flexible, user-friendly and effective. The newly developed controlling system incorporates the controlling of each optical element in the beamline, monitoring of the beam instability and softwares for data collecting. Based on the present controlling hard ware and software, a new data collecting mode using QXAFS was developed. The primary results showed that this method can be very effective for the investigation of some in-situ and fast-time-required experiments.  
        关键词：Beamline control;Synchrotron radiation;QXAFS CLC TL8   
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        发布时间：2021-03-12
      • CHEN Nian HE Duohui LI Ge LIU Jinying JIA Qika XU Hongliang ZHOU Yingui ZHANG Pengfei ZHANG Shancai LI Yuhui
        Issue 6, (2004)
        摘要：The coherent harmonic generation storage-ring free-electron laser of National Synchrotron Radiation Laboratory is composed of seed laser, optical klystron, radiation measurement system and synchronization system. Its goal is to obtain 266nm coherent harmonic radiation and higher spectral ratio. This paper illustrates the general experimental design, including the performance of electron beam, seed laser and the optical klystron. And it also gives an introduction to the scanning and focusing system of seed laser, synchronization system, magnetic gap control system, magnetic measurement system and radiation measurement system.  
        关键词：Coherent harmonic generation storage-ring free-electron laser (CHG-SRFEL);Optical klystron;Coherent radiation;Spontaneous emission CLC TN122   
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        发布时间：2021-03-12
      • HE Qing JIA Quanjie JIANG Xiaoming
        Issue 6, (2004)
        摘要：The composition in the free-standing and bilayer Ge quantum dots grown on Si( 001 ) substrate was directly determined by grazing incident X-ray anomalous scattering/diffraction ( GIXASD ) . The composition and its variation in the bilayer quantum dots separated by a 90nm thick Si spacer are similar to those of the free-standing quantum dots.  
          
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        发布时间：2021-03-12
      • TAN Weishi1,2 XU Jin2 CAI Hongling2 SHEN Bo2 WU Xiaoshan2 JIANG Shusheng2 ZHENG Wenli3 JIA Quanjie3 1
        Issue 6, (2004)
        摘要：A modulation-doped AlxGa1-xN/GaN heterostructure with 1000? Si-doped n-Al0.22Ga0.78N barrier ( n-AlGaN ) was deposited on ( 0001 ) -oriented sapphire( α-Al2O3 ) by metal-organic chemical vapor deposition ( MOCVD ) . The reciprocal space mappings ( RSMs ) of symmetric reflection ( 0002 ) and asymmetric reflection ( 1014 ) were measured with the method of high resolution X-ray diffraction ( HRXRD ) . The results indicate that the microstructure and strain status of the barrier correlate to those of the i-GaN layer. The barrier holds an “abnormal” strain-relaxation status, which probably results from the internal defects of n-AlGaN and the strain relaxation status at the i-GaN/α-Al2O3 interfaces. The results from grazing incidence X-ray diffraction show that the strain in barrier is nonuniform, which is consistent with the results from the reciprocal space mappings.  
        关键词：AlGaN/GaN heterostructure;Reciprocal space mappings;Strain relaxation;Grazing incidence X-ray diffraction CLC O472.3   
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        发布时间：2021-03-12
      • TIAN Yulian1 XIAO Tiqiao2 ZHU Peiping1 HUANG Wanxia1 LI Gang1 YUAN Qingxi1 CHEN Min2 1
        Issue 6, (2004)
        摘要：X-ray phase-contrast imaging is an important diagnostic tool in medicine, biology and materials science. At the Beamline 4W1A and TOP station of the Beijing Synchrotron Radiation Facility ( BSRF ) in China, a series of samples were investigated using three monochromatic modes of optics and based on a mechanism of quadratic dif- ferential phase contrast . We have observed phase contrast images with edge enhancement for structure of large-area samples, such as fingerling and tissue of SD rat’s lungs etc., with a few μ m of spatial resolution.  
          
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        发布时间：2021-03-12
      • HAN Jiahua XU Yong CHEN Liang ZHOU Zusheng
        Issue 6, (2004)
        摘要：In this article, the relationship between the mean lifetime of positron in metals and temperature has been deduced by the effective potential method. Our theoretical result is in agreement with the experiment very well. Using this method, we can also calculate the mean lifetime of positron in other solid materials at various temperatures.  
        关键词：Positron;Annihilation rate;Hole;Effective potential;Quasi-boson CLC O413.1   
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        发布时间：2021-03-12
      • QI Huirong1,2 XIAO Guoqing1 WANG Jinchuan1 GUO Zhongyan1 ZHAN Wenlong1 XU Hushan1 SUN Zhiyu1 LI Wenfei1 LI Chen1 CHEN Zhiqiang3 LI Wenjian1 1
        Issue 6, (2004)
        摘要：The detection efficiencies of 3 types of BGO rectangular detector units for 137Cs 0.662 MeV γ-rays are studied by theoretical calculations. The calculations are compared with GEANT4 Monte Carlo simulations and the experimental results. They are in agreement with each other very well. The differences in detection efficiencies of BGO crystals with different specifications are presented. The energy linearities for different BGO detector units are measured with 133Ba,22Na,137Cs and 60Co γ sources. For 137Cs 0.662 MeV γ-rays, the energy resolutions of BGO crystals of 20 mm×20 mm×10mm, 20 mm×20 mm×20mm and 20 mm×20 mm×30mm are 18.12%, 18.08% and 18.12%, respectively.  
          
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        发布时间：2021-03-12
      • CHANG Yinzhong WANG Xuhui WANG Jun WANG Shilian
        Issue 6, (2004)
        摘要：This paper introduces a method of measuring radioactivity in air aerosol samples with HPGe γ spectrometer. Aerosol particles were collected on a filter by a sampler. Then the filter was compressed to wafer and analyzed by a HPGe γ spectrometer. The radionuclides in the aerosol sample were identified and their concentrations in air were calculated by analyzing the obtained γ spectra. Since the level of radioactivity in aerosol samples was very low, the sample to be measured must be laid on the surface of the HPGe detector, and the coincidence summing effect should be corrected in the analysis.  
        关键词：Gamma-ray spectrometer;Air aerosol;Radioactivity CLC O517.3   
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        发布时间：2021-03-12
      • CAO Xingzhong1,2 WANG Baoyi2 ZHANG Zhiming2 WEI Cunfeng1,2 ZHANG Tianbao2 XUE Desheng1 WEI Long2 1
        Issue 6, (2004)
        摘要：A slow positron beam based on the Beijing Electron-Positron Collider (BEPC) has been constructed and tested. In this paper, transmission efficiency and other performance parameters of the system are measured by a series of experiments on the pulsed slow positron beam. Results show that the transmission efficiency of the transfer system is above 98% and the size of pulsed slow positron beam’s image got by the IP is less than 15 mm. At the same time, the energy spread of the pulsed slow positron beam is about 10 eV (FWHM). The pulsed beam intensity is about 106 slow positrons/s when BEPC is running under the short-pulse mode. It is also shown that the intensity would be reduced to half of initial value after storing 40 ms at 3×10? Pa vacuum level. 7  
          
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        发布时间：2021-03-12
      • WANG Guangfu1,2 ZHANG Huixing2 1
        Issue 6, (2004)
        摘要：The effect of second anode action on the cathode vacuum arc discharge stability in the cathode arc deposition technology is studied.The results show that the second anode action can increase arc unstable threshold of the focusing magnetic field due to the increase of the arc discharge scale and the decrease of the plasma resistor.  
        关键词：Cathode vacuum arc deposition;Second anode action;Arc stability CLC TL657   
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        发布时间：2021-03-12
      • YANG Yanqin1 ZHANG Xiaolan1,2 WU Yueying1 WU Minghong1 BAO Borong1 1
        Issue 6, (2004)
        摘要：N, N, N′, N′-tetrabutyl-3-oxa-pentanediamide (TBOPDA) presents excellent extraction abilities for the actinide and lanthanide elements and exhibits a high irradiation stability. In this paper, the effects of irradiation on extraction of TBOPDA have been studied. It is found that TBOPDA has better radiation stability. When irradiation dose reached 1000 kGy and 100 kGy respectively, the distribution ratios of U and Eu declined remarkably. The addition of diluents resulted in a decline of radiation stability.  
        关键词：γ irradiation;TBOPDA;Extraction;U;Eu CLC O615.11   
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        发布时间：2021-03-12
      • FU Zhonghua LUO Yangming WANG Heyi WANG Changbin LIU Jun HAN Jun XIA Xiulong TANG Lei
        Issue 6, (2004)
        摘要：Catalytic activities of the Pt-SDB hydrophobic catalyst for the HD(g)-H2O(l) isotopic exchange reaction were evaluated on a pilot-test system, which was constructed to demonstrate the performance of the liquid phase catalytic exchange (LPCE) process at the INPC, CAEP. It was found that the pilot demonstration system was versatile in use and convenient in process control. Experimental results have shown that, when packed with hydrophilic metallic packing in a ratio of 1/4 (V/V), the Pt-SDB catalyst exhibits high activities with a Kya mean value of 41.5 mol·m? ·s? at the temperature of 65 ℃ and the hydrogen gas flow rate of 0.2 m/s. 3 1  
        关键词：Hydrophobic catalyst;Hydrogen isotopic exchange;Trickle bed;Catalyst activity CLC O643.14   
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        发布时间：2021-03-12
      • CHEN Zhicai LIANG Shiqiang WU Meng WANG Yanling
        Issue 6, (2004)
        摘要：The experimental determination of characters of radiation field for the prostatic hyperplasia applicator can provide indispensable dosimetric parameters and physical pictures of radiation field’s change for medical practice and the research on therapy mechanism. The dose distribution of the “rectum-type” 90Sr/90Y prostatic hyperplasia applicator with arc shaped source had been determined and the absorbed doses in 336 positions had also been obtained with the lithium fluoride (LiF) thermoluminescent dosimeters (TLD’s) chips in a water-organic glass phantom. Based on the magnetic deflection and organic glass filtrating technique, the research on share of bremsstrahlung radiation dose, DR, i.e. the ratio of bremsstrahlung radiation dose to total absorbed dose, was performed in air-organic glass medium and the results show that the ratio is dependent on the distance between applicator and detector, and at the position of the maximum range of β-particles for 90Sr/90Y, DR value does not exceed 0.15%. Using organic glass as tissue-equivalent material and BaF2 as detector for determining counts of nuclear radiation, rough physical picture of the change of the nuclear radiation from the applicator in tissue was obtained and it fully accorded with the change trend of the corresponding data in dosimetry.  
          
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        发布时间：2021-03-12
      • TANG Ganghua
        Issue 6, (2004)
        摘要：Molecular imaging with positron emission tomography (PET) is an important field of molecular imaging. This article summarizes the fundamental of PET molecular imaging technique and its application in protein function, gene expression and gene therapy, receptor imaging, and blood-flow infusion and metabolism imaging.  
        关键词：Positron emission tomography;Molecular imaging;Protein function;Gene expression;Receptor;Blood -flow infusion metabolism CLC R817   
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        发布时间：2021-03-12
      • WANG Zhe WANG Jing
        Issue 6, (2004)
        摘要：Gene therapy protocols are hampered by the inability to monitor the location, magnitude, duration of transferred gene expression. With the progress of receptor imaging technology and molecule-biology, a new technic— reporter gene/imaging probe technic comes up, which becomes a good approach to monitor the gene transfer therapeutic efficacy. In the paper we review several strategies to monitor the gene therapeutic efficacy by certain receptor gene as reporter gene transferred together with therapeutic gene through radionuclide imaging.  
        关键词：Receptor;Transgenes;Radionuclide imaging CLC R817.4   
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        发布时间：2021-03-12
      • P. L. LEUNG 1 TANG Qiang1,2 Mike LI1 ZHANG Chunxiang2 1
        Issue 6, (2004)
        摘要：The single-aliquot regenerative-dose (SAR) protocol to the optically stimulated luminescence (OSL) was applied to measure the paleodose of ancient Chinese bricks with an age range from 180 to 1600 years. In the protocol, sensitivity changes can be corrected by using OSL response to a fixed test dose during measurement. For comparative study between OSL and TL, thermoluminescence (TL) measurement procedures were also applied to determine the paleodose of the bricks. Both results of OSL and TL are in good agreement with, and the paleodose ratios (DeOSL/DeTL ) are between 0.96 and 1.21, with a mean value of 1.08±0.07. The annual dose of the bricks, estimated by the paleodoses and the known ages, ranges from 5.07 to 6.85 mGy/a, comparable with the measured annual dose values. Therefore, it is concluded that the SAR protocol is a rapid and effective OSL technique to authenticate Chinese bricks.  
        关键词：Optically stimulated luminescence (OSL);SAR;Thermoluminescence (TL);Ancient bricks CLC O483   
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        发布时间：2021-03-12
      • PENG Zicheng1,2 HE Jianfeng1 LUO Xiaozhong3 LIU Guijian1 NIE Baofu4 CHEN Tegu4 1
        Issue 6, (2004)
        摘要：The techniques of thermal ionization mass spectrometry (TIMS) and multicollector-inductively coupled plasma-mass spectrometry (MC-ICP-MS) were used for the high-precision timing of the domestic stalagmite standard (GBW04412), international coral standard (RKM-4) and the Nanhai corals. The results of uranium contents and the ratios of234U/238U and 230Th/234U in the two standards measured by using two techniques were consistent within the error range. Most of the Nanhai corals have less than 3 μg /g of the uranium contents and 150±5 of the δ234U(T) values, which means that the corals have not been subjected to the alternation since they were brought up 7000 years ago, therefore, they preserve the original environmental signals. The age sequence of the corals shows that three events of the high sea level happened in Nanhai area in the periods corresponding to 6799-6307 a B.P., 4472-4285 a B.P. and 1279-1012 a B.P. respectively. The above-mentioned three stages were relative to the Megathermal and Medieval Warm Periods in our country.  
          
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        发布时间：2021-03-12
      • KANG Zhicheng DING Liren WENG Peide WANG Chuanxin
        Issue 6, (2004)
        摘要：Superconducting magnets of EAST(Experimental advanced superconducting tokamak)’s poloidal field have usually worked in zero load and variable load. It is economical that the current leads are designed as an overload lead. Some important parameters of poloidal field, such as heat load and temperature distribution, are calculated for current leads made of deferent materials at rated current and overload current in this paper. The principle of selecting material for manufacturing current lead is given. At the same time, the condition that the current lead can work at overload current is discussed.  
        关键词：Superconducting magnets;Current lead;Variable load;Experimental advanced superconducting tokamak (EAST) CLC TL62+2   
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        发布时间：2021-03-12
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