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1.
Abstract:

Heavy metals are significant and extremely persistent environmental pollutants and their toxicity is a problem of increasing significance for ecological, nutritional, and environmental reasons. Biomonitoring methods are gaining more importance because they allow for prediction, detection, and control of potential environmental hazards caused by heavy metal pollution. The objective of the present study was to collect and analyze research on heavy metal accumulation in plant samples using spectrometric detection techniques in Turkey published between 2003 and 2013. Five main criteria were predetermined to limit the study and better portray the studies on heavy metal accumulation using plant samples in Turkey. These criteria were as follows: studies aiming to determine heavy metal accumulation levels, studies sampling plant species growing at various localities in Turkey, studies using spectrometric detection techniques, studies published as journal articles, and studies undertaken between 2003 and 2013. Consequently, 47 studies that satisfied all criteria were considered and selected for this investigation. A content analysis method was used for the review and analysis of the selected studies. The results of the review analysis were grouped under three categories and the findings obtained in this scope were presented.  相似文献   

2.
本文简要介绍了近年来有限温度下奇异夸克物质的研究,包括早期宇宙中大块奇异夸克物质的研究;基于MIT袋模型的strangelet研究,以及运用质量密度相关模型对奇异夸克物质的研究,最后简略评述了关于奇异夸克物质性质的近期研究进展  相似文献   

3.
In this work, X-ray and optical studies have been carried out on a four-component isothiocyanato liquid crystal mixture with laterally substituted fluorine atoms. Molecular characteristics, such as effective inter molecular distances and apparent molecular length of the average-simulated molecule have been determined from X-ray studies at various temperatures in the liquid crystalline phase. From the nature of molecular alignment as envisaged from X-ray photographs, the orientational order parameter and its variation with temperature have been determined. Optical studies have also been conducted at various temperatures to investigate the thermal variations of birefringence. Macroscopic orientational order parameter and its thermal variation have been determined from these studies. The nature of order parameter variation obtained from the two studies, X-ray and optical have been compared.  相似文献   

4.
本文综述了中国原子能科学研究院HI-13串列加速器上的核结构研究.在原于核高自旋态方面.简要地介绍了稀土区奇质子核带交叉反常现象研究,质量数为A=90和A=130核区的高自旋态研究、原子核高自旋能级寿命研究和三轴形变研究.在原于核巨共振方面介绍了矮共振区的GDR研究,形变核的GDR以及高温转动核的GDR研究. The nuclear structure studies carried out at the HI-13 tandem in China Institute of Atomic Energy are reviewed. Brief introductions in the field of high spin state physics are given, such as the anomolous band crossing for odd-proton rare earth nuclei, high spin state studies in the mass 90 and 130 regions, nuclear high spin state life time study and the investigation of the triaxial de formation. Brief introductions in the field of GDR studies of pygmy resonance and GDR studies in deformed...  相似文献   

5.
有限温度奇异夸克物质   总被引:2,自引:0,他引:2  
本文简要介绍了近年来有限温度下奇异夸克物质的研究,包括早期宇宙中大块奇异夸克物质的研究;基于MIT袋模型的strangelet研究,以及运用质量密度相关模型对奇异夸克物质的研究,最后简略评述了关于奇异夸克物质性质的近期研究进展  相似文献   

6.
三维光谱学--二维红外光谱和时间分辨光谱   总被引:10,自引:1,他引:9  
本文介绍了一类重要的光谱学分析方法-三维光谱学方法,对其中的时间分辨光谱和二维红外光谱作了详细的介绍,包括它们的基本原理、获取谱图的方法、谱图的性质等.介绍了二维红外光谱方法在光谱学分析中的一些应用领域.三维光谱分析方法已经成为光谱分析中重要的研究方法之一.  相似文献   

7.
Single crystals of pure and Na+ doped Bisthiourea Sodium Nitrate (BTSN), semi organic crystal were grown by slow evaporation technique. The grown crystals were subjected to various studies such as single crystal X-ray diffraction (XRD), UV–vis studies, Fourier transform infrared (FTIR), TG–DTA, and Vickers's microhardness were also measured. Single crystal X-ray diffraction studies reveal the crystals belong to orthorhombic crystallographic system. The mechanical property of the grown crystal was determined by microhardness studies.  相似文献   

8.
In the present work, the interaction of Isoxsuprine (ISX) with Calf thymus DNA (ct-DNA) under physiological conditions (Tris–HCl buffer of pH 7.4) was investigated by using electronic absorption, circular dichroism, viscosity, electrochemical studies, fluorescence techniques, salt effect studies and computational studies. Competitive fluorimetric studies with Hoechst 33258 have shown that ISX exhibit the ability to displace the DNA-bound Hoechst 33258, indicating that it binds to ct-DNA in strong competition with Hoechst 33258 for the minor groove binding. Furthermore, the resulting data showed that ISX cannot displace methylene blue or acridine orange, which are the common intercalator molecules. The viscosity of ct-DNA solution was almost unchanged on addition of ISX and circular dichroism (CD) spectra of ct-DNA showed small changes in the presence of ISX which is in agreement with groove binding mode of interaction. Thus all above studies showed that the ISX drug binds to ct-DNA in a groove binding mode.The salt-effect studies showed the non-electrostatic nature of binding of ISX to ct-DNA. Moreover, molecular docking results support the above experimental data and suggest that ISX prefers to bind on the minor groove of ct-DNA.  相似文献   

9.
The applications of Mössbauer spectroscopy to studies of superconductivity are reviewed. with an emphasis on magnetic properties. Important contributions utilizing this technique have included studies of spin-lattice relaxation rates for magnetic impurities as a measure of magnetic pair-breaking effects, studies of magnetic ordering and its relationship to superconductivity in ternary superconductors such as the Chevrel phase, Re-Rh4B4 and oxide superconducting compounds, evaluation of crystal field ground states for magnetic ions, and studies of substitutional sites and the role of impurities on superconductivity in the high temperature superconductors.  相似文献   

10.
This review investigates whether there is evidence of an association between car driving and low back pain, and evidence that whole-body vibration contributes to low back pain in car drivers. The evidence of an association between various physical, psychosocial and individual factors and low back pain in car drivers was also investigated. From 23 epidemiological studies of low back problems in groups that reported car driving, nine studies fulfilled simple criteria for detailed review: four cross-sectional studies, three case-control studies and two longitudinal studies. The definition of low back pain was often unclear and, mostly, the physiological mechanisms causing low back pain were not considered. Eight of the nine studies concluded that there was an increase in low back pain among car drivers but there was little consideration of the influence of the many physical factors, individual factors and psychosocial factors that might be associated with an increase in low back pain. Consequently, there is insufficient evidence to form a conclusion on whether whole-body vibration, postural stressors or other factors, specific or not specific to driving, are common causes of low back problems in car drivers.  相似文献   

11.
Structural, optical and magnetic studies of Co-doped ZnO have been carried out for bulk as well as thin films. The magnetic studies revealed the superparamagnetic nature for low-temperature synthesized samples, indicating the presence of cobalt metallic clusters, and this is supported by the optical studies. For the high-temperature sintered samples one obtains paramagnetism. The optical studies reveal the presence of Co2+ ions in the tetrahedral sites indicating proper doping. Interestingly, the films deposited by laser ablation from the paramagnetic target showed room temperature ferromagnetism. It appears that the magnetic nature of this system is process dependent.  相似文献   

12.
An important achievement of nuclear track detectors is that they render it possible to measure a large number of radon concentrations. These are necessary for epidemiological studies aimed to estimate the lung cancer risk due to exposure to radon and its decay products in dwellings. Many case–control studies were conducted in the last 15 years in Europe, North America and China, in order to avoid the uncertainties associated with the risk extrapolation from epidemiological studies on miners exposed in underground mines. In this review paper, the main methodological issues of these studies are introduced: confounding factors, the impact of radon exposure uncertainties on the estimated risk, the retrospective assessment of radon exposure through the measurement of surface concentration on glass objects, the interaction between radon and smoking, statistical methods to analyze data and combine studies, etc. As regards the estimated risk of lung cancer, the main characteristics and results of each study are reported and discussed, together with the results of meta-analyses and, most importantly, of the three recently published analyses that pool 2 Chinese, 7 North American, and 13 European studies. Finally, some conclusions are given and a brief reference is made to ongoing studies.  相似文献   

13.
Extensive far‐infrared studies of inorganic materials and pigments in the early 1960s are highlighted and related to the many subsequent Raman studies of the same materials, studies which led to the formulation of Raman spectral libraries for use in conservation science. The need for complementary infrared/far‐infrared libraries is recognised. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

14.
核子结构研究半世纪   总被引:1,自引:0,他引:1  
评述了近半个世纪来核子结构研究的主要进展,着重评述了近十年来用极化轻子深度非弹散射研究核子自旋、磁矩结构的进展.也还评述了当前核子结构研究中的重要问题. The essential developments of the nucleon structure studies in the last half century are reviewed. The nucleon spin and magnetic moment structure studies with the polarized lepton nucleon deep inelastic scattering in the recent years are specially analyzed. The important topics in the contamporary studies of the nucleon structure is discussed.  相似文献   

15.
核子结构     
王凡 《物理学进展》2002,22(1):1-26
本文介绍了半个世纪来核子结构研究的重要进展,着重介绍了近十年来轻子核子极化深度非弹散射实验导致的有关核子自旋、磁矩结构的新进展,还介绍了当前核子结构研究中的一些重要问题。  相似文献   

16.
The thin film properties of alumina and magnesia, the substrates most frequently used in tunneling spectroscopy, are reviewed. The composite barriers, Al2O3/SiHOx and AlxSOy are also discussed. Tunneling studies provide information about absorbate-surface interactions; weak counterion adsorption effects through very strong direct chemical modifications can be studied. Tunneling studies of anionic transition metal complexes adsorbed on alumina provide significantly more information about the nature of the surface species than corresponding IR studies. The adsorption of TCNE on alumina from solution is used to exemplify how tunneling spectroscopy may be integrated into a manifold of conventional techniques (IR, ESR, and elution studies in this case).  相似文献   

17.
王凡 《物理学进展》2011,22(1):1-26
本文介绍了半个世纪来核子结构研究的重要进展 ,着重介绍了近十年来轻子核子极化深度非弹散射实验导致的有关核子自旋、磁矩结构的新进展 ,还介绍了当前核子结构研究中的一些重要问题。  相似文献   

18.
Three different powders were studied by image analysis. Shadow casting was used to generate information on particle orientation. It was discovered that orientation effects can distort the data generated in size characterization studies and as a consequence of these studies it is suggested that, in any image analysis study intended to be used to generate reference data, shadow casting‐orientation studies should be carried out to specify the orientation of the fineparticles.  相似文献   

19.
We report analytical and numerical studies of the effect of the separation distance between zeros of dielectric permittivity and magnetic permeability on the phenomena of resonant absorption and anomalous field enhancement in transition metamaterials. Our studies indicate that these phenomena are robust and strongly polarization-dependent in the presence of the spatial shift between these points. These results are likely to be important for future fundamental and applied studies in the areas of transformation, polarization, and nonlinear optics in metamaterials.  相似文献   

20.
The use of lasers for nuclear physics research is widespread and growing rapidly. The major impact in nuclear structure research has come from nuclear size and shape determinations for nuclei far from stability via high resolution isotope shift measurements. In addition, systematic data on nuclear magnetic and quadrupole moments have been obtained via the hyperfine splitting resolved in laser fluorescence studies of atomic spectra in both stable and unstable systems. The tunability, high intensity and inherent polarization of laser light can be used to polarize atomic nuclei for nuclear reaction studies. The rapid efficient polarization of unstable nuclei with lasers also presents opportunities for new research in nuclear physics. In this paper the physics of the laser interaction for the studies indicated will be introduced. Some examples of work completed and in progress will be presented primarily from on-line laser studies at charged particle accelerators. Extensions of current research, particularly with respect to possible studies of short-lived nuclei, are discussed and the synergistic effects of certain advances in quantum electronics and nuclear physics described.  相似文献   

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