古瓷中的微量元素——Ⅳ.景德镇窑场的古瓷分析之一

本文利用反应堆中子活化分析测定了湖田窑区所产的瓷片中微量元素的含量和成份。结果表明,在不同年代生产的瓷器中希土元素含量的分布模式各不相同。这正好反映了瓷胎的原料配方或是所用瓷土的种类在不同时期有着明显的差别。     

用地层元素测井(ECS)资料研究沉积环境

沉积物中某些元素的富集和贫化与沉积时的沉积环境密切相关。通过分析地层中原始沉积的元素含量与变化规律,建立与环境变化的相互关系,可以为研究沉积环境提供重要线索。地层元素测井(ECS)能够利用测井方法探测地层中Si、Ca、S、Fe、Cl、Ti、Cr和Gd等元素的含量,对各元素在地层单元中的含量及组合关系进行了分析．为沉积环境特征研究提供了依据．而各单元之间的元素变化与组合特征反映了沉积环境的变迁。     

仪器中子活化分析法测定我国水系沉积物标准参考样中的稀土元素

本工作利用仪器中子活化分析法,采用不同的照射时间和冷却时间,对十二个水系沉积物标准(代号为GSD1～12)中8～10个稀土元素进行测定,给出各标样的稀土元素的球粒陨石标准化分布模式,并试论了部分标样中稀土元素的物质来源。 5分钟照射,冷却2个小时进行测量,可测得元素Dy。10～15个小时照射,冷却4天、12天、30天进行测量,可测得元素:La、Ce、Nd、Sm、Eu、Tb、Yb、Lu。72小时照射,冷却200天进行测量,可测得元素     

水底沉积物原位X射线荧光测量中水分的影响与校正

论述了水底(海底、湖底或水系)沉积物中含水量的变化对原位X射线荧光测量的影响,以源初级X射线在沉积物上的相干散射线和非相干散射射线强度为内标建立的散射校正方程,可有效地克服沉积物中含水量变化对目标元素特征X射线的干扰。实验结果表明,对铜矿远景区土壤样品,当样品中含水量变化为20％时,目标元素(Fe：10．9％;Cu：300mg／kg;Zn：124mg/kg)特征X射线强度的变化小于5％。     

植物碳同位素组成的环境影响因素及在水分利用效率中的应用

碳同位素值（δ13C）综合反映了植物光合作用过程中气孔的传导和CO2的固定,可以作为植物在环境中生理机能变化的指标,应用于研究植物生理与生态环境之间的关系。本文主要讨论植物碳同位素组成在不同环境中的变化,并对影响程度和机理进行了探讨。降水、温度、光照、土壤盐度、大气CO2浓度等不同程度影响植物的气孔传导和CO2的固定,植物的δ13C值相应产生不同的变化。降水因素对δ13C值影响最明显,温度对δ13C值产生的影响较复杂。一般情况下,大气中CO2都是通过影响植物叶片的内外压力,造成植物碳同位素值的差异。由于δ13C值不仅可以反映植物在光合作用过程中水分的利用,而且,δ13C值与水分利用效率具有正相关性,因此,碳同位素技术应用于植物生态研究中。     

~(15)N标记的莴苣残体、废纸浆及容重对土壤反硝化及矿化作用的动态影响

介绍了不同量的~(15)N标记的莴苣残体、废纸浆及土壤容重对反硝化及矿化作用的动态影响。试验结果表明:仅施加莴苣残体能在短期内(8d)增加土壤中反硝化作用,其N_2O释放最大量为对照的15倍;仅施用废纸浆在同期内不能增加N_2O释放量。与上述两种处理比较,二者混合施用可以刺激微生物活性和增加反硝化作用,但却比仅施莴苣残体的处理N_2O释放量小,说明同单纯施用莴苣残体相比混合施用可以增加氮的固定。CO_2释放量在     

澳大利亚新南威尔士托林顿地区铀的水系取样

在新南威尔士东北部托林顿地区的花岗岩和森林覆盖地带进行了简要的试验,研究评价铀的水系地球化学取样的效果。在水系沉积物以及流经含微量铀的钨矿点的水中,均有铀量异常。诸如自然汇水区和水系沉积物中的有机物含量等相互联系的一些因素影响铀的分布,而水系沉积物中有机物含量对铀量的影响最为明显。沉积物中有机物含量的变化与河道中植物有机碎片和木炭的聚集有关,这是由于为稀疏森林所覆盖的地表受层状冲刷作用所致,特别是在地势高的汇水区内。有机物从季节性流动的河水中吸附铀,在这种环境下,当设计和解释测量结果时,必须仔细考虑水系沉积物中铀含量的季节性变化。     

~(15)N标记的莴苣残体、废纸浆及容重对土壤反硝化及矿化作用的动态影响(英文)

介绍了不同量的~(15)N标记的莴苣残体、废纸浆及土壤容重对反硝化及矿化作用的动态影响。试验结果表明:仅施加莴苣残体能在短期内(8d)增加土壤中反硝化作用,其N_2O释放最大量为对照的15倍;仅施用废纸浆在同期内不能增加N_2O释放量。与上述两种处理比较,二者混合施用可以刺激微生物活性和增加反硝化作用,但却比仅施莴苣残体的处理N_2O释放量小,说明同单纯施用莴苣残体相比混合施用可以增加氮的固定。CO_2释放量在不同处理中的全部107天中呈递减趋势,混合施用的处理中CO_2释放量每天均高于其它处理。在上述处理中,通过施加不同的压力(2,6,18kg)造成三种不同土壤容重。试验结果表明,70％的样本随容重增加N_2O与CO_2释放量增加,但差异显著性较弱或不明显。土壤容重的增加影响废纸浆的分解速率和NO_3~-与NH_4~ 浓度。     

中子活化分析法研究蕨类植物中稀土元素的分布特征

用中子活化分析(NAA)方法测定了11种蕨类植物中8个稀土元素(La、Ce、Nd、Sm、Eu、Tb、Yb和Lu)的含量，并研究了稀土元素(REE)在植物体内的分布特征。结果显示，蕨类植物叶中的稀土含量普遍较高。对于采自植物体不同部位的叶子，叶子越老，稀土元素含量越高。经球粒陨石归一化后，发现稀土元素分布模式主要是由母土性质决定的。然而，在植物从土壤吸收及输送过程中，稀土元素发生了某些不同程度的分异现象，分布模式曲线表现出与母土有明显的差异。如土壤中轻重稀土比为9．4，而芒黄叶中轻重稀土比为24—51，表明重稀土不易被植物体吸收输运。     

核技术在测定植物体中蛋白质含量方面的应用

在生物物质中测定氮的含量十分重要。这是因为氮元素与生物物质中的蛋白质含量密切相关。当然碳元素可以作为干的有机物质的指示剂,氧及其含量的变化反映了含水量的变化。目前改善和控制食物和饲料的蛋白质含量,在克服食物生产和分配短缺的问题上看来是一种最有希望的办法。植物体内蛋白质的数量与质量关系到人类和动物的营养问     

Temporal changes in vertical distribution of 137Cs in litter and soils in mixed deciduous forests in Fukushima,Japan

Downward migration of ¹³⁷Cs in soils was studied in three mixed deciduous forests c.a. 40 km northwest of the Fukushima Daiichi Nuclear power plant (FDNPP), Japan. We selected three different types of forest regarding to environmental condition such as slope inclinations and snow coverage conditions at the time of deposition. We examined temporal changes in the vertical distribution of ¹³⁷Cs from litter layers to 10 cm soil depth for two years (2.3 to 4.3 years after the FDNPP accident in 2011). At all three study sites, the ¹³⁷Cs in the litter layer had largely migrated to surface soil by 2013. After 2014, about 80% of the ¹³⁷Cs in forest soils (litter layer to 10 cm soil depth) remained within 0–5 cm soil layer. The vertical distribution had not changed substantially since 2014, suggesting that changes to the downward migration rates of ¹³⁷Cs in soils drastically decreased with time. In addition, small amounts of migrating ¹³⁷Cs could not be detected by the present method because there was a large spatial variation in the distribution of soil ¹³⁷Cs. The results showed similar patterns of soil ¹³⁷Cs distribution among the three study sites although there were differences in the environmental conditions.     

Signal processing for real-time identification of similar metals by laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy(LIBS) is regarded as a promising technique for realtime sorting of scrap metals due to its capability of fast multi-elemental and in-air analysis. This work reports a method for signal processing which ensures high accuracy and high speed during similar metal sorting by LIBS. Similar metals such as aluminum alloys or stainless steel are characterized by nearly the same constituent elements with slight variations in elemental concentration depending on metal type. In the proposed method, the original data matrix is substantially reduced for fast processing by selecting new input variables(spectral lines) using the information for the constituent elements of similar metals. Specifically, principal component analysis(PCA) of full-spectra LIBS data was performed and then, based on the loading plots, the input variables of greater significance were selected in the order of higher weights for each constituent element. The results for the classification test with aluminum alloy, copper alloy,stainless steel and cast steel showed that the classification accuracy of the proposed method was nearly the same as that of full-spectra PCA, but the computation time was reduced by a factor of 20 or more. The results demonstrated that incorporating the information for constituent elements can significantly accelerate classification speed without loss of accuracy.     

利用微土芯装置研究久效磷在水-水稻-土壤系统中的运转与分配

久效磷是一种高效、内吸、广谱性杀虫剂,是目前取代六六六的有机磷农药之一。其化学名为二甲基-1-甲基-2-甲基氨基甲酰基-乙烯基磷酸酯(顺式导构体),结构式为     

Vaporisation characteristics and detection limits of ion beam thermography

Analytical properties of the chemical speciation method, Ion beam thermography (IBT), have been investigated. IBT combines the multi-elemental ion beam techniques PIXE, PESA, pNRA and cPESA with thermography. During thermography the sample temperature is gradually increased, causing vaporisation of chemical compounds at specific temperatures and the sample at the same time undergoes analysis by the above-mentioned techniques. The characteristic vaporisation temperature (CVT) and the stoichiometric relations between the elements vaporised at that temperature, identify the chemical compounds. This work describes the reproducibility of the method, the dependence of the rate of temperature increase, the dependence of the sample thickness and the influence from aerosol particle size on the CVT. In addition the minimum detectable mass changes for IBT analysis of marine and continental aerosols were estimated by calculation for major and minor elements.     

APPLICATION OF INAA TECHNIQUE TO RESEARCH ON THE GEOGAS ANOMALY IN A GOLD DEPOSIT,SOUTHWEST CHINA

A new method of geogas (soil gas) collection and analysis, is briefly introduced. A geogas collector is buried at shallow depth to collect volatile compounds for a period of 60-90 days. The adsorbed compounds are analyzed by INAA. This paper presents the multi-elemental anomaly of a gold deposit, Southwest China.The element contents and the multielemental anomaly of geogas were compared with those in the near- surface soil around the collector, background of the collector, and in gold ores. The geogas anomaly on gold deposit is demonstrated as a direct indicator of subsurface deposits.     

Elemental and proximate analysis of coal by x-ray fluorescence assisted laser-induced breakdown spectroscopy

Although laser-induced breakdown spectroscopy (LIBS), as a fast on-line analysis technology, has great potential and competitiveness in the analysis of chemical composition and proximate analysis results of coal in thermal power plants, the measurement repeatability of LIBS needs to be further improved due to the difficulty in controlling the stability of the generated plasmas at present. In this paper, we propose a novel x-ray fluorescence (XRF) assisted LIBS method for high repeatability analysis of coal quality, which not only inherits the ability of LIBS to directly analyze organic elements such as C and H in coal, but also uses XRF to make up for the lack of stability of LIBS in determining other inorganic ash-forming elements. With the combination of elemental lines in LIBS and XRF spectra, the principal component analysis and the partial least squares are used to establish the prediction model and perform multi-elemental and proximate analysis of coal. Quantitative analysis results show that the relative standard deviation (RSD) of C is 0.15%, the RSDs of other elements are less than 4%, and the standard deviations of calorific value, ash content, sulfur content and volatile matter are 0.11 MJ kg−1, 0.17%, 0.79% and 0.41% respectively, indicating that the method has good repeatability in determination of coal quality. This work is helpful to accelerate the development of LIBS in the field of rapid measurement of coal entering the power plant and on-line monitoring of coal entering the furnace.     

Application of nuclear analytical techniques to trace elements in Cenozoic basalt and their mantle xenoliths from Aershan area in Inner Mongolia, China

Basaltic samples from different locations in Aershan area determined by instrumental neutron activation analysis (INAA) have the same distribution patterns of REE and trace elements. The similar REE contents of the same minerals without inclusions from different xenolith suggest that the mantle source region under different active volcanoes have the same composition. The REE content differences between the same minerals with and without melt inclusions selected from the same mantle xenolith indicate that the melt inclusions are rich in REE. The same patterns of trace elements of inclusions and host minerals from different xenolith analyzed by SRXRF suggest that the mantle fluid has no notable heterogeneity in Aershan area.     

海底原位PGNAA探测含水率对中子分布影响研究

运用MC法模拟14 MeV快中子进入沉积物后的物理过程,得到了不同深度下沉积物中子能谱分布,分析了0~1 eV中子在沉积物中横、纵向分布规律以及含水率与Cl~-浓度对中子分布的影响,探讨了模拟条件下0~1 eV中子扩散的最大深度范围。结果表明:沉积物含水率对中子能谱分布和0~1 eV中子横、纵向分布均有显著影响,进行中子活化的最佳深度为2 cm处;0~1 eV中子扩散的最大深度范围为20~40 cm;海水中Cl~-浓度对中子吸收有影响但影响不显著。     

Micro-PIXE studies of char populations in northern Canada

Micro-PIXE analysis of trace elements in otoliths has been used as the basis for several projects on char, a fish that is important for aboriginal subsistence fisheries in Arctic Canada. Life-history patterns were originally inferred from micro-PIXE line scans of Sr distribution. These were confirmed by superposition of Sr distribution patterns on optical images of otoliths of tag-recaptured fish. Char from various populations showed differentiation in otolith primordial Sr concentration; this enables us to differentiate biological stocks and, it is hoped, eventually to assign individuals from mixed-stock fisheries to their stock of origin. Zn oscillations also correlate with annular structure and provide additional temporally constrained information on fish habitat and behaviour.     

Penetration depth and concentrationdistribution for implanted heavy ions with low energies in plant seeds bySEM and EDS

The penetration depth and concentration distribution of implanted ions have been studied for low energy heavy ions implanted in the dry seeds of plant,such as peanut,mung bean,sunflower,wheat and radish seeds,etc.by SEM EDS.The results show that the maximum penetration depth is about 12μm for V^ with an energy 200keV implanted in cotyledon of the peanut,18μm,15μm,20μm for V^2 with 90keV implanted in sunflower,wheat,radish seeds,respectively.The penetration depth of implanted Cu^2 with 80keV is about 90μm in the remainder funicle derivative of the mung bean seeds.The experimental result of the maximum penetration depth of implanted V^ in the peanut seeds was compared with the calculated value of the TRIM95.