检索结果-南通市图书馆

The study on optically stimulated luminescence dosimeter based on the SrS:Eu,Sm and CaS:Eu,Sm

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2008年第8期17卷 3156-3162页

作者：刘艳平陈朝阳范艳伟巴维真郭旗陆妩汤新强杜彦召 Xinjiang Technical Institute of Physics & Chemistry Chinese Academy of Sciences Graduate School of Chinese Academy of Sciences

With the increasing use of nuclear energy, there is a need for a wider range of efficient dosimeters for radiation detection and assessment. There has been a tremendous growth in the development of radiation detectors and devices in the past few decades. In recent years, the development of new materials for radiation dosimetry has progressed significantly. Alkaline earth sulfides （AES） have been known for a long time as excellent and versatile phosphor materials. In the present investigation, a number of phosphor samples such as mono-, binary and ternary sulfides of alkaline earths （II^a-VI^b） have been prepared and their TL properties have been studied with respect to exposure （x-ray） response and fading. In this paper, some results on SrS：Eu, Sm and CaS：Eu, Sm phosphors are presented. A type of novel OSL dosimeter is described. The dosimeter takes advantage of the characteristics of charge trapping materials SrS：Eu, Sm and CaS：Eu, Sm that exhibit optically stimulated luminescence （OSL）. The measuring range of the dosimeter is from 0.01 to 1000 Gy. The OSL dosimeters provide capability for remote monitoring radiation locations which are difficult to access and hazardous. This equipment is relatively simple, small in size and has low power consumption. The device is suitable for space radiation dose exploration. In addition, it also can be used in IC and other radiation occasions and has good prospects.

关键词： optically stimulated luminescence radiation dosimeter

Thermoluminescence and optically stimulated luminescence disadvantages of α-Al_2O_3:C crystal grown by the temperature gradient technique

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2010年第4期19卷 445-449页

作者：杨新波徐军李红军毕群玉程艳苏良碧唐强 Shanghai Institute of Ceramics Chinese Academy of Sciences Graduate School of the Chinese Academy of Sciences Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Department of Physics Sun Yat-Sen University

Recently, α-Al2O3：C crystal with highly sensitive thermoluminescence （TL） and optically stimulated luminescence （OSL） has been successfully grown by the temperature gradient technique. This paper investigates the heating rate dependence of TL sensitivity, light-induced fading of TL signals and thermal stability of OSL of α-Al2O3：C crystals. As the heating rate increases, the integral TL response decreases and the dosimetric glow peak shifts to higher temperatures in α-Al2O3：C crystals. Light-induced fading of TL increases with the irradiation dose, and TL response decreases as the exposure time increases, especially in the first 15 minutes. With the increasing intensity of the exposure light, the TL fading of α-Al2O3：C crystal increases sharply. The OSL response of as-grown α-Al2O3：C crystal is quite stable below 373 K and decreases sharply for higher temperatures.

关键词： α-Al2O3:C thermoluminescence optically stimulated luminescence light-induced fading

Assessing conservation practices in Amalacaxco Gorge (Izta-Popo National Park, Central Mexico) using fallout 137Cs and optically stimulated luminescence (OSL)

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2018年第3期15卷 447-460页

作者： MUNOZ-SALINAS E CASTILLO M Departamento de Geología Regional Universidad Nacional Autónoma de México Ciudad UniversitariaCiudad de MexicoMexico Laboratorio Nacional de Geoquimicay Mineralogia Ciudad Universitaria Ciudad de Mexico Mexico

This study aims to assess conservation practices in Izta-Popo National Park(Central Mexico) by evaluating the mechanisms of sediment transfer. We applied a methodology based on fallout ^(137)Cs and optically stimulated luminescence(OSL) analysis. This was tested in the upper catchment of Amalacaxco Gorge, selected for being one of the sectors of the park in which man-made actions have been implemented in last decades to favor forest growth in the alpine grassland and to reduce the effect of water runoff. We quantified the ^(137)Cs activity using gamma and beta spectrometry of fine sediment grains extracted from the surface of parcels of 0.4 m2 in areas of natural forest, natural alpine grassland, alpine grassland with conservation practices, ravines and trails. In general, ^(137)Cs values increases as local slope decreases as it was expected. The natural forest is the most stable area in terms of soil erosion and sediment accumulation and, mean ^(137)Cs activity was taken as reference to assess cumulative zones, with higher ^(137)Cs values and erosive, with lower. We found that trails are accumulative surfaces but in other areas, erosion predominates. Man-made ditches, trenches and afforestation in the alpine grassland have higher ^(137)Cs values than thenatural grassland, which indicates that conservation practices are limiting the sediment transfer from hillslopes to channels, however, soil retention is less than in the natural grassland. Additionally, we evaluated the luminescence(OSL) values obtained from samples extracted from the sediment transported in ravines that are cutting into different sectors of the study area to assess the grade of resetting of fluvial materials. These luminescence results indicated that the sediment transported in ravines that are cutting into the natural forest and alpine grassland is bleached more efficiently than the sediment transported in the alpine grassland with conservation practices. Results of fallout ^(137)Cs and luminesce

关键词： Sediment transfer Soil erosion Natural protected areas Alpine grassland Caesium-137 optically stimulated luminescence

Dose-rate dependence of optically stimulated luminescence signal

在线全文

学校读者我要写书评

暂无评论

Journal of Semiconductors 2010年第10期31卷 1-4页

作者：卫平强陈朝阳范艳伟孙玉润赵云 Xinjiang Technical Institute of Physics and Chemistry Chinese Academy of Sciences Xinjiang Key Laboratory of Electronic Information Materials and Devices Graduate University of the Chinese Academy of Sciences

optically stimulated luminescence （OSL） is the luminescence emitted from a semiconductor during its exposure to light. The OSL intensity is a function of the total dose absorbed by the sample. The dose-rate dependence of the OSL signal of the semiconductor CaS doped Ce and Sm was studied by numerical simulation and experiments. Based on a one-trap/one-center model, the whole OSL process was represented by a series of differential equations. The dose-rate properties of the materials were acquired theoretically by solving the equations. Good coherence was achieved between numerical simulation and experiments, both of which showed that the OSL signal was independent of dose rate. This result validates that when using OSL as a dosimetry technique, the dose-rate effect can be neglected.

关键词： optically stimulated luminescence dose-rate numerical simulation radiation measurement

Li3PO4:M(M=Tb,Cu)phosphors for radiation dosimetry

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2017年第9期36卷 758-763页

作者： Chetan B.Palan Nikhilesh Bajaj Anuj Soni Mukund Kulkarni Shreeniwas Omanwar Department of Physics Sant Gadge Baba Amravati University Amravati 444602India Department of Physics Toshniwal ACS CollegeSengaonHingoli 431542India Radiological Physics and Advisory Division Bhabha Atomic Research CentreMumbai 400094India

The dosimetric phosphors Li3PO4：M（M=Tb, Cu） were produced by modified solid-state *** structural and morphological characterization was carried out through X-ray diffraction（XRD） and scanning electron microscope（SEM）. Additionally, the photoluminescence（PL）, thermoluminescence（TL） and optically stimulated luminescence（OSL） properties of powder Li3PO4 doped with Tb and Cu were studied. It is advocated that Li3PO4： Cu phosphor not only shows higher OSL sensitivity（25 times or more） but also gives faster decay in OSL signals than that of Li3PO4： Tb^（3＋） phosphor. The minimum detectable dose（MDD） of Li3PO4：M（M=Tb,Cu） phosphors is found to be 21.69 × 10^（-3） and 3.33 ×10^（-6） J·kg^（-1）,respectively. In OSL mode, phosphor shows linear dose response in the range of 0.02-20.00 J·kg^（-1）.In TL mode, sensitivity of Li3PO4： Cu phosphor is more than that of Li3PO4： Tb phosphor. The kinetics parameters such as activation energy and frequency factors were determined by peak shape method, and photoionization cross sections of prepared phosphor were calculated.

关键词： optically stimulated luminescence Radiationdosimetry Modified solid-state method Minimumdetectable dose

Chronology of coastal aeolian deposition and its paleo-environmental implications on the Liuao Peninsula of South China

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2019年第12期16卷 2754-2769页

作者： JIN Jian-hui LI Zhi-zhong LING Zhi-yong ZHENG Fei XU Xiao-lin CHENG Yan CAO Xiang-dong LI Zhi-xing ZHANG Wen-jing REN Yong-qing Key Laboratory for Humid Subtropical Eco-geographical Processes of the Ministry of Education Fujian Normal UniversityFuzhou 350007China Institute of Geography Fujian Normal UniversityFuzhou 350007China School of Geographical Sciences Fujian Normal UniversityFuzhou 350007China Qinghai Institute of Salt Lakes Chinese Academy of SciencesXi'ning 810008China Xinjiang Teacher's college(Xinjiang education Institute) Urumqi 830043China

Coastal dunes are a common geomorphic type in sandy coastal *** are a record of the coupled evolutionary processes of the wind and ocean *** coastal dune fields have developed on the east coast of Fujian China and now occur as widespread typical coastal aeolian sand landforms on the Liuao Peninsula,Gulei Peninsula and Dongshan Island,but it is difficult to evaluate the dynamic geomorphologic process of sandy coast due to the lack of systematic and accurate chronological *** this study,we selected the Hutoushan(HTS)aeolian dune on the Liuao Peninsula as the research *** dating and grain-size analysis were applied to sand samples from the aeolian sequence of a profile of the HTS *** results show that the ages of seven samples of this profile were in the range of 37.8–0.19 ka from 4.0 to 0.2 m *** correspond to the Marine Isotope Stage 3(MIS3),abrupt climatic change events of 4.2 and 1.1 ka and the Little Ice Age(LIA),*** samples displayed evidence of a longer-term climate trend in this *** period of formation of this coastal aeolian dune corresponds to a cold and arid climate associated with the East Asia Winter Monsoon(EAWM).Periods of dune fixation and rubification are evidence of a hot and humid *** and stabilization of the aeolian dune is an important characteristic of the coastal evolution in South China since the late Pleistocene.

关键词： Aeolian sand optically stimulated luminescence Grain size Coastal dune Environmental evolution

Quartz luminescence dating of a centennial coastal foredune from Changle in Fujian Province,East China Sea

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2022年第9期19卷 2601-2610页

作者： JIN Jian-hui LI Zhi-zhong LING Zhi-yong QIU Jun-jie Key Laboratory for Subtropical Resources and Environment of Fujian Province Fujian Normal UniversityFuzhou 350007China School of Geographical Sciences Fujian Normal UniversityFuzhou 350007China Qinghai Institute of Salt Lakes Chinese Academy of SciencesXi'ning 810008China

The Aeolian foredunes in the southern coast of China are records of paleoenvironmental changes for marine monsoon region. Intensive studies have been conducted to decipher their formation and paleoenvironmental implications in which chronology played a key role. However, robust dating results are still limited due to the scarcity of organic materials for radiocarbon and the limited application of quartz optically stimulated luminescence(OSL). Here, we collected 11 OSL samples and 140 grainsize samples from the Changle section with a thickness of 7 m from a coastal foredune in Fujian Province. The dating results indicated that the section spanned a time period from 0.32±0.04 ka(depth of 700 cm) to 0.18±0.02 ka(depth of 80 cm), after removal of age outliers. According to the OSL ages and sedimentary structural characteristics, the section could be divided into two stages, i.e. the stable accumulation period with an age range of 0.32-0.18 ka from the depth of 700 cm to 80 cm, and the activation period above the depth of 60 cm, at which the dune erosion was retained. The foredune development due to increased transport of dune sediment at the top part of the section was the result of recent human *** the foredunes, normal cross-bedding was generated by seasonal changes in wind *** changes in the wind direction were the primary cause for various sedimentary bedding within the dunes.

关键词： optically stimulated luminescence Grain size Oblique foredune Coastal South China

luminescence Dating and Bracketing Time of the Youngest Toba Tuff Deposits in the Quaternary Sediments of Purna Alluvial Basin,Central India

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2022年第4期33卷 1007-1016页

作者： Singh Ajab K.Srivastava Ashok Chauhan Naveen Department of Geology Faculty of ScienceUniversity of MalayaKuala Lumpur 50603Malaysia Department of Geology SGB Amravati UniversityAmravati 444602India Physical Research Laboratory Ahmedabad 380009India

Light gray to yellowish brown youngest Toba tuff(YTT)ash,preserved in the Quaternary sediments of India,have been used as a tool to know depositional and bracketing time period of the same in the sediments through applications of luminescence dating to interpret age connotation of various geological ***-and post-tephra sediments of YTT ash beds from Hudki and Sukali areas of Purna alluvial basin,Central India have been optically dated to interpret the depositional age and bracketing time of the tephra within sedimentary *** sediments are yellowish brown,thinly bedded,laminated,silty clay and host laterally extend discontinued beds of 0.15–0.20 m *** ash is light gray,fine grained and powdery in nature,massive to structureless and lacks any sign of retransportation and redeposition,hence,considered as primary in *** four sediment samples,one each from pre-and post-tephra lithounits of both the localities have been dated through optically stimulated luminescence technique(OSL)equipped with single aliquot regenerative(SAR)procedure on the feldspar *** shows pre-and post-tephra ages of 57±5 and 70±4 ka respectively for Hudki and 66±5 and 67±4 ka for Sukali *** depositional ages suggest that the ash was bracketed within sediments thousands years after YTT *** is correlatable with the previously reported depositional and absolute ages for the YTT ash from the localities of Ghoghara and Khuntheli,Son Valley;Tejpur,Madhumati River Basin and Jwalapuram,Jurreru *** ages also provide an idea about the period of existence of biological communities represented by the remains of faunal and vegetational activities before and during settlement of the YTT ash in the basin area.

关键词： youngest Toba tuff Tephra optically stimulated luminescence Quaternary sediments depositional age

Spatiotemporal distribution of sea-island prehistoric dune sites,Holocene sea levels,and aeolian sand activities in Fujian Province,China

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2022年第6期32卷 1157-1176页

作者： JIN Jianhui LING Zhiyong LI Zhizhong ZUO Xinxin FAN Xuechun HUANG Yunming WANG Xiaoyang WEI Changfu REN Yongqing QIU Junjie Key Laboratory of Subtropical Resources and Environment of Fujian Province Fujian Normal UniversityFuzhou 350007China Center for Southeast Environmental Archaeology of China Fujian Normal UniversityPingtan 350400FujianChina Qinghai Institute of Salt Lake CASXining 810008China International Institute of Austronesian of Pingtan Pingtan 350400FujianChina Fujian Provincial Institute of Archaeology Fuzhou 350001China College of Humanities Minjiang UniversityMinhou 350108FujianChina

The lower reaches of the Minjiang River and its adjacent areas were among the most active prehistoric archaeological areas in Fujian *** accumulation types of Neolithic archaeological strata are roughly divided into dune sites and dune/shell mound *** sites can also be roughly divided into estuarine,coastal,and sea-island sites based on their geomorphic *** cultural development of these prehistoric sites is of great significance for understanding the migration and spread of Austronesian *** on luminescence dating of typical Neolithic sites on Haitan Island,their quartz-OSL(optically stimulated luminecesence)burial ages were *** previously published results,the temporospatial distribution characteristics of the sea-island sites on Haitan Island are discussed,and the relationship between Neolithic human activities and regional geomorphic processes is *** results show that:(1)the spatial and temporal distribution of the Haitan Island Neolithic sites are closely related to small-scale geomorphic features and are controlled by mesoscale geomorphic *** sites were mainly distributed in the foothills of two high hills along an NNE-SSW *** an increase in altitude,the features were distributed as“single site(I)–superimposed site–single site(II)”and appear *** type sites(I)mainly appeared at low sea level,whereas single type sites(II)mainly appeared at high sea *** sites were not subject to sea level *** relative elevation of the superimposed sites in the study area indicates the optimal residential area for human activities in the *** single site with an elevation lower than the optimal residential area was mainly restricted by the lowest residential area,whereas the single site at a higher elevation than the optimal residential area was mainly affected by livelihood patterns.(2)High sea level caused by the“backwater effect”in low latitude areas i

关键词： Neolithic period dune/shell mound site optically stimulated luminescence Holocene sea level change aeolian activity