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101.
Mohsen M. Aly 《Journal of Dispersion Science and Technology》2013,34(2):182-213
The presence of uranium in soil and underground water generate an important issue against public perception on the risk, which the contamination poses to the environmental and human health. Uranium is the dangerous element found in nature, it found in all rocks with different ratios. As nuclear science developed, nuclear waste containing uranium increased. Contamination reached to soil, underground water and in some cases drinking water which has increased public health concerns due to the chemical toxicity of depleted uranium at elevated dosages. For this reason this review concerned to develop methods for uranium removal from low-grade and contaminated sources. There are several stationary phases and solvents used in uranyl separation process as amines in different type (primary, secondary, tertiary, and quaternary amine), phosphates, acetates, alcohols, phenols and amidoxime resins. The article addresses the main features of the following techniques for uranium: found on soil, chemical processes for separation from contaminated soils and liquor by various suitable solvent, removal by chelating resins, impregnated, and imprinted ones. 相似文献
102.
LI Lei YUE Qian TANG Chang-Jian CHENG Jian-Ping KANG Ke-Jun LI Jian-Min LI Jin LI Yu-Lan LI Yuan-Jing MA Hao H.W.Wong XUE Tao ZENG Zhi 《中国物理C(英文版)》2011,35(3)
The CDEX(China Dark matter EXperiment)Collaboration will carry out a direct search for WIMPs(Weakly Interacting Massive Particles)using an Ultra-Low Energy Threshold High Purity Germanium(ULE-HPGe)detector at the CJPL(China JinPing deep underground Laboratory).A complex shielding system was designed to reduce backgrounds and a detailed GEANT4 Monte Carlo simulation was performed to study the achievable reduction of T rays induced by radionuclides and neutron backgrounds by D(γ,n)p reaction.Furthermore,the upper level of allowed radiopurity of shielding materials was estimated under the constraint of the expected goal.Compared with the radiopurity reported by other low-background rare-event experiments,it indicates that the shielding used in the CDEX can be made out of materials with obtainable radiopurity. 相似文献
103.
煤炭地下气化反应动力学特性的研究 总被引:6,自引:3,他引:3
煤炭地下气化过程中,高温的碳与二氧化碳和水蒸气发生的非均相反应决定了出口煤气的组分和热值。鉴于此,在煤焦与CO2和H2O(g)反应活性实验的基础上,研究了唐山刘庄煤焦与CO2和H2O(g)气化反应的动力学特性,确定了其化反应的速率表达式,得出其反应活化能分别为140.41kJ/mol和171.53kJ/mol。实验结果表明,还原带温度在1000℃-1100℃时,CO2具有较高的还原主;温度达1000℃时,H2O(g)分解可视为不可逆反应,且生成CO的反应速率明显大于生成CO2的反应速率,出口煤气组成中CO的浓度为CO2的7倍多,在上述工作的基础上,建立了“收缩反应核”模型,并分析了多相化学反应速度与温度的关系。 相似文献
104.
A. N. Guz 《International Applied Mechanics》2003,39(1):20-48
The fundamentals of the theory of stability of mine workings are analyzed. The theory is based on the linearized three-dimensional theory of stability of deformable bodies. Some results on horizontal and vertical mine workings and on underground closed cavities are analyzed 相似文献
105.
106.
A semi-analytical method of solving the problem of dynamic stress concentration of arbitrary underground structure under the effect of blast waves was introduced. Using the Fourier transform theory, the shock waves (in the forms of SH-waves) can be converted into frequency bands. After employing complex functions and conformal mapping, the admittance functions of various underground structures were obtained. Then, the problem of the time domain dynamic stress response of underground structure can be easily solved through the Fourier inverse transform. At last, the results and curves of the dynamic stress for the square, triangle and horseshoe cavity were presented. 相似文献
107.
108.
This paper compares three methods for natural gas dehydration that are widely applied in industry:(1) absorption by triethylene glycol, (2) adsorption on solid desiccants and (3) condensation. A comparison is made according to their energy demand and suitability for use. The energy calculations are performed on a model where 105 Nm3/h water saturated natural gas is processed at 30 °C. The pressure of the gas varies from 7 to 20 MPa. The required outlet concentration of water in natural gas is equivalent to the dew point temperature of -10 °C at gas pressure of 4 MPa. 相似文献
109.
A telescope of area 4 m2, consisting of horizontal layers of plastic scintillators, neon flash tubes and absorbers was operated at a depth of 754
hg/cm2 in the Kolar Gold Mines. New values for the vertical intensities of muons have been obtained from observations of the angular
distribution over the slant depths ∼ 750–2300 hg/cm2 and are compared with the existing measurements. From the angular distribution observed, we conclude that muons are produced
wholly through the decay of pions and kaons up to energies of the order of 1 TeV. A value of 0.3±0.2 is estimated for theK/π ratio at production, for muon energies around 500 GeV. A decoherence distribution has been obtained for parallel muon events
up to distances of the order of 10 m. From this we conclude that the averageP
t of the parents of muons of energy ∼ 250 GeV is of the order of 0.3 GeV/c. From an analysis of rock showers, we obtain the
cross section for inelastic interaction of muons of mean energy 100 GeV as (3.8±1.5)×10−30 cm2/nucleon. 相似文献
110.
电感耦合等离子体发射光谱法测定地表水和地下水中的硫酸根、磷酸根和硼酸 总被引:3,自引:0,他引:3
采用电感耦合等离子体发射光谱法(ICP-AES)测定地表水和地下水中的全S、P、B来近似代替水中的SO42-、PO43-、H3BO3。结果表明,ICP-AES法可同时测定地表水和地下水的SO42-、PO43-、H3BO3,方法检出限分别为0.0265、0.0320、0.0192mg/L。方法的相对标准偏差(RSD,n=6)为0.5%~6.1%,加标回收率为91.9%~102.2%,经与单个项目分别测定的方法比对实验,测定值无明显系统偏差。方法快速、准确,经国家标准物质验证,结果与标准值相符。 相似文献