最新刊期
      卷 0 ， 期 0 ， 2020
      • ZHAO Hua1 LU Yanchou2 WANG Chengmin1 MAO Hongliang1 JI Honglei1 1
        Vol. 34, Issue 2, (2011)
        摘要：OSL dating method has been widely used for dating sediments,most of which are wind-laid.There are many difficulties to use OSL dating method for dating water-laid deposits,such as alluvial,fluvial and lacustrine deposits,which need more chronological data support and contain abundant information of regional climate and environment change,ancient flood,ancient earthquake and geological structure.Therefore,application of the OSL dating method in water-laid deposits has been baffled to some extent.Can optical signal preserved in mineral particles of water-laid deposits be bleached in the process of transportation and deposition? Is that bleaching even? How is the residual level? How to determine the equivalent dose of nature optical signal intensity of the water-laid deposits? How to mensurate the equivalent dose accurately? These are decades-long problems concerned by OSL dating researchers home and abroad.In this paper,progresses in this field of research are reviewed,the recent research status and problems are discussed,and prospect of applying the OSL dating method to water-laid deposits is given.  
        关键词：Water-laid deposits;OSL dating;Bleaching degree   
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        发布时间：2021-03-05
      • LUO Daling TANG Qiang ZHANG Chunxiang
        Vol. 34, Issue 2, (2011)
        摘要：The accuracy to describe thermoluminescence(TL) mechanism depends on the defect models used principally.The TL kinetic theory models are based on the isolated point defects hypothesis.In fact,the kinetic parameters obtained from experimental TL glow curves have little physical significance.It is known that a lot of TL physical phenomena cannot be explained by the TL kinetic theory models.Based on analysis of TL emission spectra and nonlinearity of TL dose responses in the series of alkaline earth sulphate doped with rare earth ions and phosphors,it is supposed that the defects in these phosphors should be formations of large defect complexes,which include intrinsic imperfects and dopants.These defect complexes can be regarded as basic elements in the TL multi-stage processes.It has been observed that the TL characteristics and the nonlinearity of dose responses depend on the structure of these defect complexes obviously.  
        关键词：Defect complexes;Thermoluminescence emission spectrum;Dose response   
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        发布时间：2021-03-05
      • TANG Qiang1 ZHANG Chuan1 CHEN Shaowen1,2 FAN Lixian2 LIU Xiaowei1 1
        Vol. 34, Issue 2, (2011)
        摘要：An α-counter with time coincidence function was developed to measure U and Th contents in geological samples for TL(thermoluminescence) and OSL(optically stimulated luminescence) dating.The U and Th contents in geological samples are calculated by α total counting rate and pair coincidence counting rate,and the annual dose rate can be estimated.Tests of the α-counter showed that the measurement results were comparable with that of a NaI γ spectrometer.  
        关键词：U and Th content;Time coincidence;α-counter   
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        发布时间：2021-03-05
      • LIU Chunru1 YIN Gongming1 GAO Lu1 LI Jianping1 LIN Min 1,2 HAN Fei1 1
        Vol. 34, Issue 2, (2011)
        摘要：ESR dating samples need be irradiated to obtain dose response curve and the equivalent dose.The artificial dose rate is about 1×10–1–1×102 Gy/min,whereas the natural dose rate is about 3 Gy/ka.Therefore,one must be sure whether the much higher artificial dose rate is suitable for the ESR dating study.In this paper,we use different artificial dose rate to irradiate the same fluvial sample and measure the quartz Al centre ESR signal under the same conditions.The dose response curves are compared,in an attempt to gain a preliminary knowledge on that problem and build a good foundation for our ESR dating studies on fluvial samples.  
        关键词：Artificial irradiation;Dose rate;Sediment;ESR;Quartz   
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        发布时间：2021-03-05
      • ZHU Hongying TANG Kaiyong ZHAO Jianxing ZHOU Chunzhi MA Xinghua CUI Hui NAN Qinliang SUN Tao
        Vol. 34, Issue 2, (2011)
        摘要：In this work,we investigated detection threshold of a thermoluminescence(TL) dosimetry system.Main factors of the TL reader affecting the detection threshold were analyzed.The influences of metallic planchet,filter,environments and atmosphere on the detection threshold were investigated experimentally.The ways to improve the sensitivity and detection threshold were proposed.The detection threshold of RGD-6 rotary reader was 0.044 μGy after the reader was calibrated by GR-200A LiF(Mg,Cu,P) TLD.  
          
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        发布时间：2021-03-05
      • ZHAO Jianxing WANG Feng TANG Kaiyong LI Haijun LIU Dahai XIAO Wuyun CUI Hui
        Vol. 34, Issue 2, (2011)
        摘要：The basic features,performances and principle of the newly developed model RGD6 TL reader are introduced in this paper.The functions for continuous and automatic measurements are described in detail.Experiment results show that the RGD6 TL reader meets the need of automatic TL dosimetry measurement,with good performance in sensitivity and data dispersion.  
        关键词：TL reader;Dose readout;Function design   
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        发布时间：2021-03-05
      • CHEN Qiang1,3 YE Yuguang1,3 DIAO Shaobo2
        Vol. 34, Issue 2, (2011)
        摘要：Optically stimulated luminescence(OSL) dating method,an important method for Quaternary sediment age determination,has been successfully applied to terrestrial sediments such as loess.However,applying OSL dating method to marine sediments should be explored.In this paper,the multiple-aliquot regeneration-dose of OSL dating is used to date marine sediments samples from the Yellow Sea of China.Four samples were taken from different depths of a drill core,and quartz grains of 4–11 μm were separated for OSL dating,while organic carbon samples were taken from the same sampling positions for AMS 14C dating,so as to check the OSL dating results.It turns out that the OSL dating results agree well with the AMS 14C dating results within the AMS 14C detection limit(47 ka).  
        关键词：Optically stimulated luminescence;Marine sediment;Multiple-aliquot regeneration-dose method;AMS 14C   
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        发布时间：2021-03-05
      • WANG Ping1 LI Jianping1 WANG Jiancun1,2 LIU Chunru1 HAN Fei1 GAO Lu1 1
        Vol. 34, Issue 2, (2011)
        摘要：Xigeda formation is a famous fluvial-lacustrine sedimentation formed in late cenozoic in southwest China,distributed in the valley of Dadu River,Anning River,Chin-sha River etc.The age of Xigeda formation,ranges between 4.18 and 1.78 Ma BP,depending on the magnetic stratigraphy research of the stratigraphic section.Quartz Ti-center in ESR dating of sand samples from several typical sections of Xigeda formation in Sichuan shows that they are sediments in mid-pleistocene.Comparing the ESR ages and mainly normal polarity,Xigeda formation can be confirmed in Brunhes epoch according to magnetic stratigraphy.  
        关键词：Xigeda formation;ESR;Ti-center;Magnetic stratigraphy;Paleo-dammed lake   
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        发布时间：2021-03-05
      • HAN Fei1,2 YIN Gongming1 Jean-Jacques Bahain2 Tristan Garcia3 LIU Chunru1 GAO Lu1 LI Jianping1 1
        Vol. 34, Issue 2, (2011)
        摘要：Paleodose determination is essential for ESR dating,and the DE value is influenced by the mathematical functions used for dose response data points fitting.At present,single saturation exponential(SSE) fitting is commonly used for ESR dating.It is valid when the number of trap sites is constant,but when the increasing irradiation dose induces new traps,the dose response curve will not follow a unique SSE function.In this study,in addition to SSE,the double saturation exponential(DSE) and exponential plus linear(EPL) functions were used to fit the ESR data of eight tooth fossil samples from Longgupo early Pleistocene site in Wushan,Chongqing.The results show that the DE values calculated by SSE fitting function are systematically higher than DSE and EPL,and the residual sum of square of SSE is larger than the other two.Compared with known reference dose value,we found that DSE has the smallest relative deviation among the three functions,and the SSE has the largest deviation.The study indicates that the SSE function overestimates DE value of tooth fossil samples from old sites,while the DE value determined by DSE functions seems closer to the true value of paleodose.  
        关键词：Paleodose;Fitting functions;ESR dating;Tooth fossil;Longgupo site;Single saturation exponential(SSE);Double saturation exponential(DSE)   
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        发布时间：2021-03-05
      • GAO Lu YIN Gongming LIU Chunru HAN Fei LI Jianping 1
        Vol. 34, Issue 2, (2011)
        摘要：Gouge is the carrier for information of the fault activity.In this study,fault gouges from the eastern Liupanshan piedmont fault zone were analyzed by ESR method.However,the measured ESR age is much older than that estimated in the field.On the other hand,SEM images of the quartz grains separated from the fault gouge showed a variety of morphologies,which indicate several periods of fault movements.The ESR age estimates failing to represent the latest fault movement suggest that the latest movement may not have zeroed ESR signals significantly for ESR dating and the quartz may be from different periods of the movements.Although there are still many uncertain factors in the ESR dating of fault gouge,it is essential to study systematically in this area.  
        关键词：ESR dating;Fault gouge;SEM;Liupanshan fault   
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        发布时间：2021-03-05
      • LI Haijun MA Xinhua WANG Ying ZHAO Jianxing LIU Dahai ZOU Shiya ZHOU Chunzhi
        Vol. 34, Issue 2, (2011)
        摘要：In this article,we introduce the performance of industrial computer EM9000,and describe the design and system function modules of the control software for the EM9000-based thermoluminescence reader.The solution of real-time glow curve transformation is discussed.The system has high measurement efficiency and detection sensitivity.It is convenient and reliable to store and read data.  
        关键词：Industrial computer;Thermoluminescence reader;Software design   
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        发布时间：2021-03-05
      • SONG Yan1,2 GE Yonghui2,3 CUI Suxia1 1
        Vol. 34, Issue 2, (2011)
        摘要：Circular dichroism spectroscopy is widely used to studies the secondary structures of protein and DNA,and identify the interaction of the biomolecules.In this work,we analyzed the SRCD spectra between 230–255 nm and found that the Gd@C82(OH)22 fullerene nanoparticles were capable of affecting the secondary structure of λ-DNA and λ-DNA HindIII.We also tested the melting temperature(Tm) of both kinds of DNA,and found that after treated with Gd@C82(OH)22 nanoparticles both of the Tm values decreased significantly.By analyzing SRCD spectra between 180–200 nm we found that the information of DNA supercoil structure could be obtained.The results show that Gd@C82(OH)22 nanoparticles can affect the secondary structure and thermostability of λ-DNA and λ-DNA HindIII,and the λ-DNA supercoil structure as well.  
        关键词：λ-DNA;Gd@C82(OH)22;SRCD;DNA secondary structure;DNA supercoil   
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        发布时间：2021-03-05
      • ZHANG Mingyi1 WANG Peng2 XING Gengmei1 ZHANG Jun2 1
        Vol. 34, Issue 2, (2011)
        摘要：To investigate influence of different-sized nanoparticles on stability of cell DNA,RAW264.7 strains were incubate with 30 nm and 50 nm COOH-labeled polystyrene beads(COOH-PBs).Synchrotron radiation circular dichroism spectroscopy(SRCD) was used to analyze possible transformation of the secondary structure of DNA,which was further confirmed by means of comet assay.The CD spectra indicated that both particles could reduce helicity of the DNA and increase the degree of DNA single strands.The 30 nm-PBs treatment did more damage than the 50 nm-PBs treatment.This suggests a size-dependent influence.It is demonstrated that SRCD provides a reliable method to investigate the stability of cell DNA influenced by nanoparticles.  
        关键词：DNA;Nanoparticles;SRCD   
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        发布时间：2021-03-05
      • CHEN Xi1,2 CHENG Fengmei1 LI Haidong1 ZHANG Jidong2 1
        Vol. 34, Issue 2, (2011)
        摘要：Thin films of α phase polyoctylfluorene were prepared by thermal annealing spin-coating at 120oC,which is confirmed by absorption and photoluminescence spectra.The microstructure was characterized by using one-dimensional and two-dimensional grazing incident X-ray diffraction.The results show that molecular chain of the PFO is mainly parallel to the substrate with edge-on orientation.  
        关键词：Grazing incident X-ray diffraction;Polyoctylfluorene thin film;Microstructure   
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        发布时间：2021-03-05
      • WANG Fei1 LIU Wei2 TANG Jingchun1 1
        Vol. 34, Issue 2, (2011)
        摘要：oil is main source to absorb atmospheric hydrogen,and tritium released from nuclear reactors,through the oxidation of hydrogen and tritium gas by soil microorganisms.In this paper,hydrogen and tritium migration and transformation in the environment,microbial species,distribution and microbial community associated with tritium oxide was reviewed.Hydrogenase,the mechanism of biological oxidation of tritium,and factors affecting tritium oxidation in soil,were discussed.Studies show that tritium oxidation was affected by the soil microbial community,and this is an important factor in site selection of nuclear power plants.  
        关键词：Tritium;Hydrogenase;Soil;Isotope   
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        发布时间：2021-03-05
      • XU Qiang1 YANG Tiqiang2,3 WANG Miao4 1
        Vol. 34, Issue 2, (2011)
        摘要：amples of the α-amylase were treated with 1015–1016 ions/cm2 of 20 keV N+.The secondary structure of the ion-implanted α-amylase was studied by circular dichroism,and activity change of the α-amylase was analyzed.The results showed that in the dose range under investigation,the N+ implantation affected the relative contents of α-helix,β-sheet,β-turn and random coil of the α-amylase,but no significant differences were found between the samples implanted to different doses.The activity of the N+-implanted α-amylase changed,with a relationship between the activity increase and the conformation change.  
        关键词：Ion beam implantation;α-amylase;Circular dichroism;Secondary structure;Enzyme activity   
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        发布时间：2021-03-05
      • LI Dongli1,2 XU Yikai2 WANG Quanshi1 WU Hubing1 LI Hongsheng1 1
        Vol. 34, Issue 2, (2011)
        摘要：In this paper,we investigate the diagnostic value of 11C-methionine(MET) positron emission tomography/computed tomography(PET/CT) for brain gliomas,and compare the results to 18F-fluorodeoxyglucose.Forty-four patients with suspected gliomas were examined with 11C-MET and 18F-FDG PET/CT.18F-FDG and 11C-MET PET/CT images were compared and evaluated by visual and semiquantitative analysis.The accuracy of 11C-MET and 18F-FDG PET/CT for detecting gliomas were 88.6% and 65.9%,respectively.Semiquantitative analysis showed that the 26 gliomas had higher mean ± SD T/NGmax ratio on 11C-MET PET/CT than on 18F-FDG PET/CT(1.95±0.52 vs.0.90±0.27,t=9.101,P<0.001).11C-MET had a higher sensitivity than 18F-FDG(83.3% vs.33.3%,χ2 =4.16,P<0.05) for low-grade gliomas,but it did not differ significantly from 18F-FDG in the sensitivity for high-grade gliomas(100% vs.64.3%,χ2=3.20,P>0.05).The difference was no significant,too,between high-and low-grade gliomas,compared by 11C-MET T/NGmax ratio(2.07±0.51 vs.1.81±0.52,t=1.302,P=0.205).18F-FDG T/NGmax ratio in high-grade gliomas was significantly higher than that in low-grade gliomas(1.03±0.30 vs.0.75±0.11,t=3.198,P=0.004).It is concluded that 11C-MET PET/CT is more accurate than 18F-FDG PET/CT for detecting and delineating gliomas,especially for low-grade gliomas,and it can play a complement role to 18F-FDG in tumor grading.  
        关键词：Glioma;PET/CT;Methionine;Deoxyglucose   
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        发布时间：2021-03-05
      • GE Liangquan1 ZENG Guoqiang1 LAI Wanchang1 FAN Zhenguo2 NI Weichong3 XIONG Shengqing2 1
        Vol. 34, Issue 2, (2011)
        摘要：In this paper,we report a newly developed AGS instrument.The probe is composed of five 5 NaI(Tl) scintillators of 10 mm×10 mm×40 mm size.Four of them detect the ground,and the fifth detects the sky.A temperature sensor,a preamplifier with circuit negative feedback and a high voltage supply with lower noise are designed.A Y/U double channel digital controlled gain amplifier for fine adjustment of the spectral drift,and high speed ADC and CPLD,are designed to perform digital spectroscopy and improve the energy resolution and pulse through output rate(>100 k/s).Two self-stabilization spectrum loops are designed for spectrum stability.The first loop performs rough adjustment(temperature),and the second loop does the fine adjustment by a Kalman filter.The AGS system has the following specifications: energy range of detection,0.02–10.0 MeV;the spectral drift,±1 channel;and spectrum collection time of 0.5–1 s.The 20 NaI(Tl)+PMT scintillation counters can be operated at the same time.  
        关键词：Airborne gamma-ray spectrometry;Gamma-ray spectrometry;Nuclear geophysical exploration   
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        发布时间：2021-03-05
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