首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 468 毫秒
1.
Instrumental neutron activation analysis (INAA) was used for the determination of major, minor and trace elements in samples of bottom sediments of the inflows of the Selenga river basin to assess the impact of the contamination from the industrial complex Erdenet and other industrial enterprises in Mongolia. A total of 42 elements (Na, Mg, Cl, K, Ca, Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Sr, Rb, Sr, Zr, Nb, Sb, Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Dy, Tm, Hf, Ta, W, Au, Hg, Th, and U) was determined by combination of conventional and epithermal neutron activation analysis at the IBR-2 reactor, FLNP JINR, Dubna. For the first time such a large set of elements was used for characterization of the bottom sediments as accumulating media which may reflect industrial contamination of the water basin. The concentrations of heavy metals and other trace elements in the samples from three inflows of the Selenga river basin were compared with data from the previous studies. It was shown that the industrial zone of the Erdenet Mining Corporation (EMC) and gold mining zone Zaamar are the sources of strong environmental contamination. The concentrations of Cu and Sb determined in sediment samples of the River Khangal and Govil near the EMC exceed average crustal rock and soil values by factors of 50 and 15, respectively. In the area of the gold mining zone Zaamar concentrations of Au, As, and Sb exceed crustal rock and soil values by factors of 4, 25, and 6, respectively. The relatively high levels of As, V, Zn, V, and Sr in the sediments of the studied rivers are obviously due to the discharges of untreated wastewater of desalination plant, electrical power station, textile industry and mining activities as well as domestic wastewater.  相似文献   

2.
A number of phenomena that determine the nature of the fluorescence of free complex molecules and the possibility of its analytical application are considered. Attention is specially paid to the specific features of the energetics of radiationless transitions, the role of statistical factors in the formation of spectral properties and the interrelationship among the luminescence-spectrum characteristics of rarefied vapors of complicated molecules, and the processes of energy transfer in collisions. The properties of polarized fluorescence of hot and jet-cooled vapors, the processes of relaxation of anisotropy in time and during collision reorientation, and transfer of anisotropy in photodisintegration are analyzed. Institute of Molecular and Atomic Physics, National Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 5, pp. 620–634, September–October, 1998.  相似文献   

3.
采集了石河子城区32个站点的道路尘土样本,测定了样品中10种非常规监测微量元素(B,Be,Bi,Co,Ga,Li,Sb,Sn,Tl,V)的含量。并采用地积累指数法、元素相关性分析和主成分分析法对尘土中的微量元素污染程度和来源进行了分析。结果表明:道路尘土中微量B,Be,Bi,Co,Ga,Li,Sb,Sn,Tl和V的平均含量分别为41.11,1.68,0.52,13.58,36.26,24.91,3.37,3.64,0.42,72.66 mg·kg-1。其中,Co,Li和Tl的平均含量均低于新疆土壤元素背景值,B,Be和V的平均含量和新疆土壤元素背景值相似,Bi,Ga,Sb和Sn的平均含量高于新疆和世界土壤元素背景值。地积累指数计算结果表明:B,Be,Co,Ga,Li,Tl和V污染级数为0,说明无污染,而Sb,Bi和Sn污染较为严重(污染等级分别为2,1,1)。元素相关性分析和主成分分析多元统计方法计算结果表明,Bi,Co,Sb和Tl主要是人为来源,B,Be,Li和V主要是自然来源,而Ga和Sn可能受自然因素和人为因素的共同影响。  相似文献   

4.
本文主要介绍了化探样品相态分析中无火焰原子吸收光度法测定化探样品中的铜、铬、钴、镍、铅、镉的分析方法。近年来,随着地质找矿工作的发展,地球化探人员对相态分析技术越来越感兴趣,在相态分析中,不同相态同一种元素的含量相差很大,给溶液的提取,制备及测定工作带来了很多不便,加之,大量的常量元素的存在尤其是钙、镁、锰、铁等元素极易产生干扰,在水溶态,离子态的分析液中铜、铬、钴、镍、铅、镉的含量又很低,给测试带来了很大难度,在相态的提取过程中,如果做平行、样品分析的话一个样品至少要制备八份溶液,工作量很大,因此,找到一个简单,快捷而又稳定可靠的测试方法是十分必要的,在测定中采用了磷酸为基体改进剂,它不仅可以消除基体的干扰,并可使各种元素测定的精密度得到很大改善。  相似文献   

5.
A homogeneous neuron-like medium with close nonlocal coupling between the positive center and the negative surroundings is used for image processing. The input image is transformed into a stationary structure dependent on the form of the coupling function and the type of the element's response to external action. Using the idea of plausible activity structures, we can determine the model parameters needed to extract the features of the medium such as the contour, the lines of definite direction, the ends of lines, the central axes of the image, the negative, the points of intersection of lines, the texture boundaries, and the objects of definite scale as well as the parameters that permit reconstruction of broken lines, smoothing of lines, automatic determination of image scales, and binarization of the initial image by a medium with a tunable coupling function.Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 37, No. 8, pp. 1053–1061, August, 1994.  相似文献   

6.
Radio reception     
The last few decades saw considerable progress in the methods of reception of radio signals, in particular, in the short-wave part of millimeter wave range. Along with this, or, perhaps, owing to this, some views, concepts, and definitions in the theory of detection and mixing were changed. Consequently, for example, the concepts and the corresponding apparatus developed in the 1950s need at present certain corrections. Below we propose a nonstandard consideration of the detection and mixing processes on the basis of consistent observance of the principle of information theory on the energy character of signal reception and using the time-domain approach when describing the operation of superheterodyne converters. To my teacher in practical radiophysics, professor Izrail’ Lazarevich Bershtein with gratitude. Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 41, No. 11, pp. 1378–1398, November, 1998.  相似文献   

7.
Based on the results of studying hemoglobin and myoglobin molecules using the methods of laser absorption spectroscopy of superhigh time resolution, we described photophysical and spectral properties of excited states, and intramolecular electronic and thermal relaxation processes. A mechanisms of the photodissociation reaction of oxy forms of these proteins is proposed and substantiated. Reported at the VIIIth International Conference on Spectroscopy of Porphyrins and Their Analogs, Minsk, September 22–26, 1998. Institute of Molecular and Atomic Physics, National Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 4, pp. 479–482, July–August, 1999.  相似文献   

8.
Diffractometric phase analysis of the structures of alloys on copper base, containing small concentrations of Mn, Pd, Al, Ti, Zr, Ce, and Ni, and of films on their base, was carried out. The differences in the structure of initial bulk samples of the alloys, and of condensates obtained by sputtering in vacuum, are discussed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 101–105, November, 1973.  相似文献   

9.
We present the results of comprehensive investigations that include remote spectral measurements under field conditions, laboratory experiments, and mathematical simulation of the radiative regime of winter rye sowings. B. I. Stepanov Institute of Physics, Academy of Sciences of Belarus, 68, F. Skorina Ave., Minsk, 220072, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 5, pp. 646–650, September–October, 1997.  相似文献   

10.
Development of cosmonautics and preparation to the first manned space flights are briefly observed. Details of the development of the first Soviet intercontinental ballistic missile R-7, which served as a basis for creating Sputnik, Vostok, Voskhod, Molniya, and Soyuz launchers, are given. The contributions of the outstanding designers of space engineering, W. von Braun, S.P. Korolev, V.P. Glushko, and academician M.V. Keldysh, to the development of astronautics and first manned space missions are demonstrated. A list of test launches and manned flights of Vostok and Mercury spacecrafts and the basic characteristics of Vostok, Redstone, Atlas-D, Voskhod, and Soyuz launchers are presented.  相似文献   

11.
We analysed structural differences between midgut epithelial cells of fed instar antlions' larvae Euroleon nostras and starved ones. In starved larvae the presence of autophagolysosome-like structures was observed, which are characteristic structures associated with autophagy. The results presented here provide insight supporting the role of autophagy as a cell survival mechanism for the periods of food deprivation. Additional structural changes in the cytoplasm were seen in the spherites. The ultrastructure and chemical composition of spherites in the midgut epithelial cells of first, second and third instar larvae were observed with light microscopy and transmission electron microscopy (TEM). A detailed characterization of the elemental composition of the spherites was studied using analytical electron microscopy; a combination of energy dispersive X-ray spectroscopy (EDXS), electron energy-loss spectroscopy (EELS) and energy filtering TEM (EFTEM) was applied. The structure and elemental composition of the spherites changed during the period of larval life. Moreover, changes in chemical composition were found between spherites from fed and starved E. nostras. In fed first instar larvae, the spherites contained an organic matrix, composed of C, N and O. In this matrix, P, Cl, Ca and Fe were detected. In starved first instar larvae, only C, N and P were present. The spherites of fed second instar larvae were rich in organic and inorganic elements and were composed of C, N, O, Na, Mg, P, S, Cl, K, Ca, Mn, Fe and Zn. In starved second instar larvae, the chemical elements N, O, P, Ca and Fe were found. In fed third instar larvae, the spherites contained C, N, O, Na, Mg, P, Cl, K, Ca, Mn, Fe, Co and Zn. In starved third larvae, C, O, Si, Ca, and Fe were detected. Generally, the spherites are exploited in starved larvae. These results suggest that the elemental supply of spherites may provide crucial support for physiological processes during starvation periods amongst E. nostras instar larvae. In some cases in fed second and fed third instar larvae, spherites were seen in the lumen of the midgut. Such spherites could serve as reservoirs for nontoxic waste material that cannot be metabolized.  相似文献   

12.
The isotopic composition of the heavy elements Ti, Fe, Br, Sr, Ba, Nd, Gd, Dy, and Pb, contained in rock samples, on the sea bottom, and in sea shells, was measured by the method of laser mass spectrometry. The experimental data obtained are compared with the main characteristics of nuclear isotopes — spin, magnetic moment, electric quadrupole moment, and neutron binding energy. A correlation was observed between the combination of signs of the magnetic moment and electric quadrupole moment and the anomalous fractionation of isotopes of heavy elements. The behavior of protoisotopes and magic nuclei is studied.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 89–94, January, 1988.  相似文献   

13.
Self-maintained glow discharge at atmospheric pressure in a helium flow is used as an excitation source of spectra for analysis of the metals Na, Ca, Pb, Cd, and Zn in aqueous solutions of their salts. The intensities of the analytical lines of these metals are obtained as a function of the concentration, and the detection limits for each element are determined. Deceased. Institute of Molecular and Atomic Physics, Academy of Sciences of Belarus, 70, F. Skorina Ave., Misnk, 220072, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 6, pp. 711–715, November–December, 1997.  相似文献   

14.
研究了用碳粉、碳酸钙、氧化铜和氧化铍作缓冲剂同时测定钛基复合材料中的镍、铁、钼、锰和硼的发射光谱法,选择铍作内标线,不需分离、不需化学处理,直接压样于杯形的石墨电极中,具有简便、快速、准确。对测定条件、干扰因素进行了研究,从而建立测定镍、铁、钼、锰和硼的新方法。镍、铁、钼、锰和硼的分析线分别为300.36,248.33,315.82,260.57和249.68 nm,内标线选择为铍的298.61 nm,镍、铁、钼、锰和硼的线性范围分别为0.003%~0.30%;0.001%~0.20%;0.003%~0.30%;0.001%~0.20%;0.001%~0.20%。镍、铁、钼、锰和硼的检测限分别0.003%,0.001%,0.003%,0.001%,0.001%,其回收率在95.80%~104.8%范围内,当n=9时,相对标准偏差RSD均小于5%。用于样品的测定取得了满意的结果。  相似文献   

15.
比较紫色,红色和黄色三种新疆野生樱桃李及栽培品种果肉中无机元素的含量,样品采用微波消解方法进行前处理,ICP-MS法检测其中K,Ca,Mg,Na,Fe,Mn,Cu,Zn,Be,Li,Se,Sr,Cr,Pb,Cd,As,Hg等17种元素。该检测方法快速简便,精密度高且具有较高的灵敏度,17种元素的加标回收率在93.5%~110.4%。分析结果表明紫色,红色和黄色三种新疆野生樱桃李及栽培品种果肉中的17种元素含量均较为接近,均含有极为丰富的K元素,含量高达1‰左右,Ca,Mg,Na,Fe,Mn均为含量较高的金属元素且含量依次降低,Cu,Zn,Li,Se,Sr,Cr也有一定含量,Pb,Cd,As,Hg等有害元素含量极低或未检出。实验结果为研究新疆野生樱桃李与栽培品种果肉中微量元素含量提供参考数据。  相似文献   

16.
各种矿质元素在荆芥各器官间贮藏差异。从矿质元素角度了解荆芥合理的药用部位组成以及收时间。应用ICP-AES技术,测定并分析了在不同采收时间,荆芥的不同器官矿质元素含量、累积量和比例。结果显示, 在不同采收时间,(1)荆芥穗中常量矿质元素K, P和微量矿质元素Cu含量最高,荆芥叶中常量元素Mg, Ca, Na和微量元素Fe, Mn, Zn含量最高。(2)荆芥不同器官所含常量元素中Ca和K含量最高,Na含量最低;所含微量元素中Fe含量最高,Mo含量最低。(3)在荆芥茎中,K∶P最高,而Zn∶Cu则为最低;Ca∶Mg和Fe∶Mn在荆芥穗中最低。(4)随着采收时间的推移,各元素在荆芥不同器官中的含量变化并不显著。荆芥茎中各矿质元素含量均较低; 从矿质元素含量的角度看,在合理的采收时间范围内,荆芥的质量受时间影响不显著。  相似文献   

17.
龙王山墓葬位于湖北省荆门市,属于大溪文化向屈家岭文化过渡的关键时期,距今约5 000年。该墓葬共出土玉器73件,玉器品质普遍较好。长江中游地区历来鲜少出土玉器,而时代更迭之期更是社会变革之际,无论是从地理位置还是从时期上来看,研究龙王山墓葬出土的玉器都具重大意义。采用相对密度检测,红外光谱仪(FTIR)及激光剥蚀电感耦合等离子体质谱仪(LA-ICP-MS)研究出土玉器的谱学及化学成分特征,鉴定其材质,并对用料水平及矿源进行了探究。红外光谱结果显示龙王山墓葬出土玉器的红外吸收谱图可分为两类:软玉类和玛瑙类。软玉类玉器的红外吸收峰表现为1 207, 1 123, 1 028, 928, 775, 700, 602, 488和425 cm-1处。玛瑙类玉器的红外吸收峰表现为1 158, 814, 790, 702, 572, 521及405 cm-1。软玉类玉器有71件,且品质都非常好,说明龙王山墓葬先民对玉料的分选能力很强。将龙王山墓葬的用料水平与同时期其他地区的考古学文化的用料水平进行对比,龙王山墓葬的用料水平远超同期;将龙王山墓葬的用料水平与...  相似文献   

18.
A method of the atomic-emission spectrum analysis of soil has been developed for control of the accumulation of technogenic impurities in environmental objects. A sample, after calcination at 550°C, is evaporated in an arc discharge. Spectra are recorded by a DFS-8 spectrograph. Simultaneously, determination is made of Li, Ba, Sr, Cu, Zn, Cr, Ni, Co, Pb, Bi, Mo, V, Ge, Ga, Y, Nb, Sn, Cd. For the majority of the elements the detection limits are lower than their percent abundance in the crust and their maximum permissible concentrations. Institute for Single Crystals, National Academy of Sciences of Ukraine, 60, Lenin Ave., Khar'kov, 310001, Ukraine. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 3, pp. 396–399, May–June, 1997.  相似文献   

19.
用高压罐消解样品,以正交试验原理,利用ICP-AES测定柞树叶及柞树皮中Zn、Fe、Mg、Ca、Se、K、Cu、Ge、P、Mn共10种微量元素的含量.方法回收率在96.00%-103.00%之间,相对标准偏差小于1.97%.ICP-AES具有简单、快捷,准确度高等特点,且多元素同时测定,更适合柞树叶、柞树皮中金属与非金属元素的分析测定.实验证明,柞树叶、柞树皮中含有Zn、Fe、Mg、Ca、Se、K、Cu、Ge、P、Mn等大量对人体有益的微量元素,说明柞树叶和柞树皮发展前景广阔.  相似文献   

20.
应用电感耦合等离子体质谱(ICP-MS)测定了北京顺义、河北阜平和河北平山三个地区65个荆条蜜样品中38种元素含量,其中B,Na,Mg,P,K,Ca,Fe和Zn等8种元素的含量处于较高水平,其浓度均高于1 mg·kg-1。比较发现,不同地区荆条蜜中元素含量存在一定差异。以具有显著性差异(p<0.05)的29种元素(Na,Mg,Al,K,Ti,V,Mn,Fe,Ni,Cu,Zn,Ga,As,Sr,Y,Mo,Cd,Ba,La,Ce,Pr,Nd,Sm,Gd,Dy,Ho,Tl,Pb和U)为变量,应用主成分分析(PCA)和反向传输人工神经网络(BP-ANN)两种化学计量学方法按照不同产地对荆条蜜进行了分析。PCA可将所有变量降为4个主成分,并能解释81.6%的变量,结果表明,PCA基本可以将荆条蜜按照不同产地分开。应用BP-ANN建立不同产地荆条蜜溯源模型,用全部样本建立模型时,三个产地荆条蜜分类的正确率均为100%,采用“留一法”进行交叉检验,整体准确率为95.4%;以75%的样本建立模型,25%的样本用于预测,对BP-ANN模型的可靠性进行验证,三个产地整体分类和预测的准确率均为100%。ICP-MS测定蜂蜜中多元素含量结合多变量模型可以实现不同产地荆条蜜溯源。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号