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11.
《地球科学进展》2015,30(12):1295
The interaction between ions and soil particles plays an important role in the mobilization and bioavailability of ions in soils, which is one of the main research areas of soil chemistry. The new method based on suspension Wien effect has been developed recently to determine the binding energy and adsorption energy between ions and soil particles. Compared with other methods on the basis of adsorption isotherm or ions activity, Wien effect method has more advantages including convenience and direct measurement. The term suspension Wien effect refers to the increase of electrical conductivity of suspension with increasing applied electrical field. In this review paper, we introduced the fundamentals of suspension Wien effect, the apparatus about the Wien effect measurement, and along with demonstrating their application to quantifying the particles-ions interactions for several systems of soils. Our studies indicated that divalent cations have larger binding energies and adsorption energies on soil particles than monovalent because of the electrostatic interaction. However, few studies about the interaction between Cr3+ and La3+ on soil particles showed that the binding energy and adsorption energy of trivalent cations are lower than those of divalent cations because of hydrolysis. Soil properties such as soil organic matter, soil pH, and iron oxides significantly affected the binding energy and adsorption energy of ions. Our results deepened our understanding about the non specific adsorption of ions in soil chemistry, and enlarged the research area of soil chemistry in fundamental and methodology.  相似文献   
12.
针对我国西部地区地貌的专题地图集空缺的现状,《中国西部地区典型地貌图集》的编制填补了这一空白,该图集是以表达我国西部地区十省(市、自治区)典型地貌形态特征为主题的区域性专题地图集,是国家西部测图工程成果之一。该文阐述了该地图集的概况,重点从图集编制原则、内容结构、表达方法、装帧设计等各方面详细介绍了该地图集的内容设计与编制特色。地图集为地学相关领域进行科学研究、测绘部门地貌表达以及相关院校科研教学等提供技术资料。  相似文献   
13.
14.
This study aimed to optimize the purification of recombinant growth hormone from Paralichthys olivaceus. Recombinant flounder growth hormone (r-fGH) was expressed by Escherichia coli in form of inclusion body or as soluble protein under different inducing conditions. The inclusion body was renatured using two recovery methods, i.e., dilution and dialysis. Thereafter, the refolded protein was purified by Glutathione Sepharase 4B affinity chromatography and r-fGH was obtained by cleavage of thrombin. For soluble products, r-fGH was directly purified from the lysates by Glutathione Sepharase 4B affinity chromatography. ELISA-receptor assay demonstrated that despite its low receptor binding activity, the r-fGH purified from refolded inclusion body had a higher yield (2.605 mgL-1) than that from soluble protein (1.964 mgL-1). Of the tested recovery methods, addition of renaturing buffer (pH 8.5) into denatured inclusion body yielded the best recovery rate (17.9%). This work provided an optimized purification method for high recovery of r-fGH, thus contributing to the application of r-fGH to aquaculture.  相似文献   
15.
The concentrations of Cu, Zn, Cr, Ni, Pb, As, Mn and Co were determined by Inductively Coupled Plasma–Mass Spectrometry both in recent sediments from different locations of the Huelva littoral (SW Iberian Peninsula) and in their humic acid (HA) fractions in order to evaluate distribution and binding capacity of those trace elements to HAs. In addition, elemental composition (C, N, S) and δ13C values were determined to appraise the sources of organic matter in the area. This study involved the comparison of selected samples taken from different environments including the estuary of the Guadiana River, the main fluvial system of the region, the Tinto and Odiel estuary system and the proximal shelf. Significant positive correlations were found among Cu, Zn, As and Pb in bulk sediments, suggesting a common origin of all of those elements: the mining activities and pyrite deposits located hinterland. On the other hand, results for Cr, Co and Ni pointed to the basic rocks from the low basin of the Guadiana River as their main source. Elemental (C, N) and isotopic (δ13C) composition of sediments indicated a significant contribution of autochthonous plankton in coastal shelf sediments, whereas estuarine and riverine sediments showed a major contribution of terrestrial biomass. Geochemical values for their corresponding HAs suggested a greater terrestrial contribution in the sedimentary OM of the coastal shelf sediments than in bulk sediments, which evidenced the influence of coastal currents and sediment fluxes. Humic acids sequester considerable amounts of Cu and Zn contributing to reduce the bioavailability of these contaminants.  相似文献   
16.
Interpretation of Ni2p XPS spectra of Ni conductors and Ni insulators   总被引:1,自引:0,他引:1  
Ni2p3/2 X-ray photoelectron spectral peak binding energies of Ni metal, NiS, and NiAs (all conductors) span a range of about 0.5 eV and are, consequently, insensitive to formal Ni oxidation state and to the nature of the ligand to which Ni is bonded, relative to other metals (e.g., Fe). Ni2p3/2 peak structures and binding energies reflect two energetic contributions. The major contribution is that associated with the electrostatic field produced by ejection of the Ni(2p) photoelectron, the minor contribution is the relaxation energy associated with filling unoccupied, conduction band 3d9 and 4s Ni metal orbitals. These conduction band orbitals become localized on the Ni photoion (and sometimes filled) in response to the field created by the photoemission event. Because only the core Ni2p electron and nonbonding orbitals of predominantly metallic character are affected, the main peak of all three conductors are affected similarly, leading to similar Ni2p3/2 main peak binding energies. NiO, Ni(OH)2, and NiSO4 are insulators in which Ni is divalent and is bonded to oxygen. Although Ni is bonded to oxide in these phases, Ni2p binding energies differ substantially, and reflect primarily the nature of the ligand (O2−, OH, SO4 2−) to which Ni is bonded. The influence of the ligand is the result of charge (electron) transfer from valence band bonding orbitals of dominantly ligand character, to unoccupied conduction band orbitals localized on Ni photoions. Relaxation energy resulting from charge transfer is acquired by the emitted photoelectron, thus Ni2p3/2 photopeak binding energies of these insulators reflect the nature of the ligand to which Ni is bonded. The Ni2p main peak binding energy of these conductors and insulators is a poor guide to Ni oxidation states. The Ni2p3/2 binding energies of insulators reflect, however, the nature of the ligand in the first coordination sphere of Ni. The intensity of the Doniach–Sunjic contribution to Ni2p XPS spectra of NiS and NiAs is dependent on the nature of the ligand. The Doniach–Sunjic contribution to ligand XPS core-level photopeaks (e.g., S2p of NiS and As3d of NiAs) has not been explained and is poorly understood. Received 24 May 1999 / Revised, accepted: 30 June 1999  相似文献   
17.
辽东湾北部浅海区底泥砷元素形态特征   总被引:3,自引:1,他引:2  
刘明华 《地质与资源》2010,19(1):32-35,41
依据2006年辽东湾浅海评价资料,分析了辽东湾北部浅海底泥的砷元素全量和各形态的含量,对砷元素全量和存在形态的分布特征及相关性进行了系统研究,并探讨了其环境生态效应.结果表明:底泥中的砷含量为较高水平,存在形态主要为残渣态、腐植酸结合态和铁锰氧化态,而水溶态、碳酸盐结合态、离子交换态和强有机结合态含量较少.除砷的强有机结合态以外,全量和其他6种形态有很好的相关性,分布特征一致,高值区都分布在锦州湾及附近.并且生态效应明显,底泥中砷的腐殖酸结合态、铁锰氧化态、离子交换态与脉红螺中砷有显著相关性,碳酸盐结合态与锯缘青蟹和口虾蛄中砷有一定的相关性.  相似文献   
18.
《地图礼赞——献给内蒙古自治区成立七十周年》是为庆祝内蒙古自治区成立七十周年而精心编制的一部史诗型横向8开本专题图集,图集充分运用平面设计理论和色彩理论,通过色彩重构和纹理重建,艺术化地展示了内蒙古自治区成立以来取得的辉煌成就以及"十三五"制定的宏伟蓝图。本文主要介绍了图集在版面整饰设计、色彩艺术策划、图集装帧设计等方面的研究成果和创新模式。  相似文献   
19.
提出了矿渣粉加固粉土的相关理论。将矿渣粉在加固土中的作用归结为火山灰胶凝效应和微集料填充效应,而火山灰胶凝效应又可进一步归结为水化作用、激发作用和离子交换作用;认为微集料填充效应与矿渣粉细度极为相关;用框图归纳了矿渣粉加固土的两种作用效应。进行了矿渣粉、石灰粉加固土无侧限饱水抗压强度、水稳定性、冻稳定性、温度收缩和干燥收缩等路用性能试验,并进行比较。结果表明,矿渣粉加固土所测路用性能指标优于石灰粉加固土。为工程应用提供了试验依据。  相似文献   
20.
By studying the cylindrically symmetric solution for matter in 2+1 space-time dimensions we arrive at stability criteria for such a configuration when the local energy density is proportional to the square of the tension (negative pressure). Our analysis demonstrates that to the post-Newtonian approximation that such a configuration is stable provided it does not shrink below a certain radius. We find our model provides a reason for how stars form from a two-dimensional configuration with both a maximum mass and a minimum radius.  相似文献   
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