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1.
正墓葬环境中土壤的理化性质是文物工作者发掘和出土文物的重要依据,也是影响文物是否保存完整的因素。土壤易溶盐,极易导致土质文物发生"盐害",进而使得文物出现不同程度的破坏[1]。在湿润的环境下,土壤中的SO42-、NO3-会形成对应的酸,不仅对文物造成腐蚀,还会毒害土壤中有益的微生物[2]。高氯含量的墓葬土壤会造成青铜器腐蚀、铁锚锈蚀,还会引起土壤盐渍化[3-4]。土壤中酶的活性和酸度受到氟含量的影响,当  相似文献   

2.
从棕色金龟提取甲壳素   总被引:3,自引:0,他引:3  
甲壳素(chitin),又名甲壳质,几丁质,化学名为(1,4) 2 乙酰氨基 2 β D 葡聚糖,它广泛存在于无脊椎动物的外壳中,是一种用途广泛的碱性多糖。[1 2]壳聚糖(chitosan)是甲壳素脱乙酰化的产物,又名脱乙酰甲壳质。甲壳素和壳聚糖具有特殊的理化性质和生物学功能,应用广泛[3],目前主要从虾、蟹壳中提取[3 4]。棕色金龟(Holotrichiati tanusReitt)属鞘翅目,数目繁多,可危害植物的叶、花、芽及果实等地上部份,并随温度的变化作垂直迁移,春时会上升到地表为害,冬夏则在土壤中深处潜伏。本文分别从棕色金龟…  相似文献   

3.
芳烃在原油中的含量仅次于烷烃和环烷烃,因此在油气地球化学勘查工作中,芳烃组分的测定一直是一项重要的研究内容。由于油气化探工作所涉及的样品大多为近地表土壤,而源于油气藏的各芳烃组分在向地表迁移过程中的轻重分异效应,使得各类芳烃组分特别是重芳烃组分在近地表土壤中的含量甚微[1],因此在芳烃组分的高效液相色谱测试中,选择适当的检测波长以便使检测方法达到其最大灵敏度是该技术的关键。1实验部分1.1主要仪器与试剂高效液相色谱仪:HP1090型,美国惠普公司;色谱柱:Hypersil C18柱(30 cm×4.6 mm i.d.,10μm),大连依利特公司;荧光…  相似文献   

4.
利用超大规模分子动力学模拟程序研究了[111]||[110]双晶铜纳米线的拉伸断裂行为. 针对样品的周期性结构, 开发了离散傅立叶变换进行晶体特征分析的技术. 通过转换实空间的原子密度分布函数, 得到振幅-频率图和归一化的长轴原子密度分布图. 这两种处理方法提供了晶体取向和结晶状态的信息, 其中振幅-频率图适合描述大范围的晶体特征, 而归一化长轴的原子密度分布则反映了局部的细节. 利用该方法, 考察了不同拉伸时刻[111]||[110]双晶铜材料的晶体取向和结晶状态. 在拉伸过程中, 从振幅-频率图可以观察到4.78 nm-1处的[111]特征峰和7.81 nm-1处的[110]特征峰发生了低频移动和峰形变宽的现象; 同时在断裂时刻观察到了5.50 nm-1处的[100]特征峰. 证明[111]||[110]铜双晶纳米线在拉伸形变过程中发生了界面融合, 同时界面层原子向[100]晶向的转变, 最终导致了双晶纳米线在[111]晶向一侧断裂. 傅立叶变换晶体分析技术在纳米材料和器件的研究中可以发挥积极的作用.  相似文献   

5.
本文采用上升液滴法,研究了氯化铀酰在盐酸介质和磷酸三丁酯(TBP)之间的传质过程.在一定浓度的盐酸溶液中,TBP 萃取铀的速率与[U]和[TBP]_(0)~2成正比;反萃速率与[U]_(0)成正比,而与[TBP]_(0)成反比.在温度为20~40℃范围内分别测定了萃取和反萃反应的活化能,它们的差值与由萃取平衡分配比与温度关系测得的焓变相符.可以认为,萃合物 UO_2Cl_2·2TBP 的生成和离解都是分步进行的,中间产物是 UO_2Cl_2·TBP;萃取速率的控制步骤是 UO_2Cl_2·2TBP 的生成反应,而反萃速率的控制步骤是 UO_2Cl_2·TBP 的离解反应.  相似文献   

6.
本文采用上升液滴法, 研究了氯化铀酰在盐酸介质和磷酸三丁酯(TBP)之间的传质过程. 在一定浓度的盐酸溶液中, TBP 萃取铀的速率与[U] 成正比; 反萃速率与[U] 成正比, 而与[TBP] 成反比. 在温度为20~40 范围内分别测测定了萃取和反萃反应的活化能, 它们的差值与由萃取平衡分配 温度关胤系测得的焓变相符,可以认为, 萃合物UO2Cl2TBP 的生成和离解都是分步进行的中间 物是CU2Cl2TBP; 萃取速率的控制步骤是UO2Cl22TBP 的生成反应, 而反萃速率  相似文献   

7.
毛细管电泳电化学检测法测定红葡萄酒中的多元酚   总被引:1,自引:0,他引:1  
目前 ,人类各种疾病约 89%起因于活性氧 .因此消除活性氧基团 ,使过氧化物对机体的损伤降到最低限度已成为研究的热点 [1] . Maxwell等 [2 ] 测试了红葡萄酒在人体血液中的抗氧化能力 .发现从刚喝下红葡萄酒时起 ,抗氧化活性就开始上升 ,90 min后达到最大 ,抗氧化活性平均上升约 1 5 % .葡萄酒中的多酚含量与活性氧消除能力的相关系数高达 0 .9686,所以确立葡萄酒中多元酚的分析方法有重要意义 .红葡萄酒中含有酚酸类、儿茶素类、黄酮类等多酚类化合物 ,通常采用气相色谱[3] 、高效液相色谱 [4 ] 测定 .毛细管电泳 ( CE)应用于葡萄酒中多…  相似文献   

8.
近年来,食品中的农药残留问题受到越来越多的重视.国内外关于水果蔬菜等食品中的农药残留研究多集中于对食品原料的报道.尽管有机氯农药已禁用多年,但因其化学性质稳定、脂溶性强、易在环境和生物体中富集,至今仍能在大气[1]、水体[2]及土壤[3]中检出.  相似文献   

9.
离子色谱法测定腊肉中氯离子   总被引:1,自引:0,他引:1  
食盐是人们生活中不可缺少的物质,但长期过量摄入易导致高血压。腊肉制备过程中添加了大量的食盐,用于防腐和保鲜。国家标准关于腊肉中食盐允许量的规定为不超过10%[1]。目前氯离子测定的方法有硝酸银滴定法[2]、比浊法[3]、氯离子选  相似文献   

10.
铀污染土壤的植物修复研究   总被引:2,自引:0,他引:2  
核工业的发展,导致重金属铀的排放和扩散,造成了地表土壤的污染,对社会和环境造成了很大的影响,如何修复被铀污染的土壤成为了一个难题,近年发展起来的植物修复技术以其成本低廉、安全、环保的特点成为修复被铀污染的土壤的新选择.寻找理想的超富集植物是这一技术的基础和关键之所在,通过实验模拟铀污染土壤(土壤中铀的浓度为1.00×1...  相似文献   

11.
The earthquakes cause appearance of new geological fault and dislocation of rock stratum; the original permeable rock breaks, then the fault can conduct water under the effect of pressure; the stratum with radionuclide is dislocated and connected to the water-conducting fault under the effect of the fault. Under the effect of water the stratum with seepage and the one with radionuclide link up. It causes radioactive pollution on underground water, based on which this paper does a research and makes an analysis of the radioactive pollutant concentration that diffuses along the top and bottom section and centre line of the fault following the seepage. It turns out that in the rock stratum with seepage suffering rupture, the radioactive pollutant effects an elliptical spherical diffusion. In the turning point of the fault, the elliptical sphere makes a turn following the seepage.  相似文献   

12.
Grant DF  Eastwood D 《Talanta》1983,30(11):825-830
An infrared field-method has been developed which is capable of distinguishing between oils originating from natural seepage in the Santa Barbara (California) Channel region and closely similar oils from onshore drilling platforms. The technique involves a minimum of sample preparation and the use of simple infrared instrumentation which can be operated by non-technical personnel. Natural seep-oil samples were collected from the surface of the water, underwater, and from beaches in the area. The non-seep oils were obtained from production wells which were located in the same geographical areas as the seepage and were from several different well depths corresponding to different geological zones. Natural seep-oils are more aromatic than the production oils, and this difference is evidenced by observed differences in the spectra for both weathered and unweathered oils. These spectral differences between seep and non-seep oils have been found to persist after exposure to weathering for a week.  相似文献   

13.
Epoxy/clay nanocomposites with a high degree of exfoliation were achieved using a so-called "slurry-compounding" process with which the dispersed state of clay in water can be successfully transferred to an epoxy matrix. In this process sodium montmorillonite was first exfoliated and suspended in water. This suspension was further treated with acetone to form a clay-acetone slurry followed by chemical modification using silane. The modified slurry was then mixed extensively with epoxy to form epoxy/nanoclay composites. It has been shown that the morphologies of clay before and after curing are quite similar and the exfoliation process is termed "slurry compounding". Furthermore, the amount of organic modifier used is only 5 wt % of clay, in contrast to conventional organoclays which normally contain at least 25-45 wt % of organic surfactant. The resulting epoxy/nanoclay composites exhibit a high degree of clay exfoliation and a better thermal mechanical property.  相似文献   

14.
The sorption and desorption of uranium on two different clay samples which are obtained from the deposit located in Turgutlu and Kula have been studied by application of a batch technique. The two types of clay materials are Ca-montmorillonite. The uranium concentration range was between 200–3000 ppm. Experimental procedures are outlined and results for uranium contacted with montmorillonite are reported and discussed. The sorption/desorption isotherms were reversible and non-linear for this concentration range. The relative importance of test parameters e.g., pH, clay particle size, temperature, ground water composition, contact — time, solid/water ratio which require definition in order to arrive at meaningful distribution coefficients were carried out. The sorption coefficients varied between 0.65–1.45 and 0.45–1.14 for Kula clay and for Turgutlu clay, respectively. The data could be fitted to Freundlich and Langmuir isotherms. The quantity of the sorbed and desorbed uranium ions was much lower than its theoretical CEC's. This was attributed to a blocking of montmorillonite's CEC by uranium islands sorbed in interlayer. The results have shown that the test parameters can have a marked effect on sorption and the present work provides further evidence of the need to take account of the presence of such materials in safety assessment modeling.  相似文献   

15.
The effects of cationic polyethylenimine (PEI) on the colloidal stability of anionic fines (microcrystalline cellulose or thermomechanical fines), fillers (clay) and their mixtures in deionized and tap water were investigated, using a photometric dispersion analyzer. Measurements confirmed that PEI flocculates all used materials by charge neutralization. As expected, higher additions of PEI lead to electrostatic stabilization of microcellulose and clay suspensions, but it was not possible to stabilize the suspension of fines using high additions of PEI. This is ascribed to the mechanical entanglements of fibrillar fines. In tap water, much more PEI is needed to reach optimum flocculation conditions than in deionized water. Heteroflocculation between PEI-coated clay and fines takes place with a rate which, for high fines concentration and a constant clay concentration, is independent of fines concentration. A theoretical model for the heteroflocculation of fines with PEI-coated clay has been developed, which explains the observed trends. In essence, clay particles can act as bridging agents for fines flocculation.  相似文献   

16.
疏水化水溶性两性纤维素接枝共聚物与粘土的相互作用   总被引:3,自引:0,他引:3  
运用紫外光谱法研究了疏水化水溶性两性纤维素接枝共聚物(羧甲基纤维素接枝丙烯酰胺及N,N 二甲基辛基(2 甲基丙烯酰氧乙基)溴化铵的共聚物, CGAO)在粘土上的吸附,考察了聚合物浓度、无机盐浓度、温度、 pH、 表面活性剂和粘土浓度等因素对CGAO在粘土上吸附量的影响,以及通过X射线衍射分析了CGAO在粘土上的吸附位置.结果表明, CGAO在粘土上的吸附规律与一般聚合物有很大差别,而且CGAO未深入到粘土晶层间,只在其表面吸附. 粘土与CGAO作用前后的粒度分析表明CGAO对粘土粒子有很好的桥接聚集作用. 扫描电镜分析显示粘土与CGAO作用后,其颗粒形态发生了显著变化.  相似文献   

17.
Water diffusivity D measured by using NMR techniques in Na-smectite suspensions decreases with increasing smectite fraction (up to 50 wt%), but increases with increasing salinity (NaCl or CaCl(2) aqueous solutions) at a fixed clay fraction. The increase, larger for CaCl(2) solutions, is explained by aggregation of clay particles when high salinities are reached. Macroscopic organisation of dense mixtures of clay and aqueous solutions can be inferred by T(2) transverse NMR relaxation times which are sensitive to the volume to surface ratio. Dispersed suspensions exhibit mono-modal T(2) distributions, whereas bimodal T(2) distributions are observed for flocculated systems. The bimodal T(2) distributions are interpreted as a measurement of the spacing between clay particles within aggregates and between aggregates. Finally, the diffusion data can be gathered in an unique curve using the Debye length and the measured spacing between particles. When the thickness of the electro-diffuse layer (Debye length) is of the same order as the spacing between clay particles, the water diffusivity decreases. Otherwise it is constant at about 2.22+/-0.25x10(-9) m(2)/s. This last result illustrates clearly the effect of electro-chemical properties of smectite on water diffusivity.  相似文献   

18.
Chemical, colloidal, and geochemical transformations in an open dissipative ecosystem atmosphere–water basin–water body floor composed of clay carbonate metamorphosed sedimentary rocks were considered using both model, natural, and technogenic objects. Based on the model of interactions of the acidic components with mineralized water and clay carbonate water body floors, it was shown that the process of carbonate karst at the reservoir bottom can be one of the reasons for the plastic flow in benthic part of ground dam. The role of oscillation processes in carbonate dissolution at a nanolevel and in their metamorphic and technogenic transformations was clarified. It was established that, at low external stresses, plasticized clay carbonate structures decrease their viscosity by several times and are deformed in an oscillating regime which is especially pronounced at the initial period of stress loading.  相似文献   

19.
ABSTRACT

Polymer/clay aerogel composites fabricated using the freeze-drying method and water as solvent has drawn extensive attentions during the past decade. Such aerogels possess layered or network microstructures, low thermal conductivities, and good thermal stabilities; of special interest, they generally have very low flammability, which could be influenced by the composition and microstructure of the aerogel composites. The fire performance of the aerogels can be further improved with flame retardant modifications. Polymer/clay aerogel composites can also serve as effective flame retardant coatings. The mechanisms of the flame retardancy of polymer/clay aerogel composites are also discussed herein. The thorough survey of the current literatures offers useful information to realize potential of polymer/clay aerogels and help guidance to design novel high-performance polymer/clay aerogel composites.  相似文献   

20.
The effect of co-occurring inorganic species on the removal of tungsten from water was investigated using biosorbent (i.e., chitosan coated montmorillonite clay). Simulated natural water and well water from Fallon, NV were used for this study. The concentrations of tungsten (21-541 mg/L) and inorganic species ([H(2)CO(3)]=0-4.2 mg/L, [H(4)SiO(4)]=0-90 mg/L, and [SO(2-)(4)]=0-400 mg/L) in simulated feed water were varied. The concentration of tungsten in the well water was 26 microg/L. The pH level of simulated feed water and well water was adjusted to 4 since this pH was found to be the most effective pH for the tungsten removal using chitosan coated clay. Tungsten removal without the existence of co-occurring inorganic species decreases from 99.8 to 87.1% with an increase in initial tungsten concentration from 21 to 541 mg/L. It reduces further as the co-occurring inorganic species concentration increases. The percentage of the tungsten removal ranges between 68.2-93.8%, 66.7-94.2%, and 53.6-93.7% for simulated natural water containing varied amount of H(2)CO(3), H(4)SiO(4), and SO(2-)(4), respectively. The adsorption kinetic data could be best described by the pseudo second order expression. The adsorption equilibrium data was modeled with the Langmuir, Temkin, and Freundlich equations and was found to be represented well by the Langmuir equation. The essential characteristics of the Langmuir isotherm indicate that the adsorption of tungsten on chitosan coated clay is favorable regardless of the presence of interfering species. Compared to natural clay, chitosan coated clay has about 116 times larger adsorption capacity per gram of chitosan, which makes it a superior adsorbent. However, the maximum tungsten adsorption capacity decreases in the presence of co-occurring species since the co-occurring species suppress the adsorption. For the well water treated with biosorbent, the tungsten concentration in the product water was found to be lower than the detection limit (1 microg/L) of the inductively coupled plasma mass spectrometer (ICP-MS). The repeatable results obtained from the treatment of both simulated and well water suggest that using chitosan coated clay can be an efficient adsorbent for tungsten removal from contaminated sites.  相似文献   

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