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131.
采用等温吸附试验方法研究了模拟酸雨对荔枝果园土壤磷的吸附与解吸特性的影响。试验结果表明,不同处理间土壤对磷的最大吸附量(Xm)为pH2.5>pH4.5>CK=pH6.5,其中pH2.5的酸雨淋溶处理对磷的最大吸附量(Xm)与其它处理间差异显著;土壤吸附磷的解吸量(Xd)分别与相应的吸附量(X)和原平衡溶液浓度(C)呈显著的指数相关和线性相关,随着土壤对吸附量的增加,土壤磷的解吸量呈指数增长。 相似文献
132.
基于非饱和土的平面应变抗剪强度统一解,考虑非饱和特性与中间主应力对土体强度的共同影响,利用瑞典简单条分法推导了非饱和土边坡安全系数的系列化新解,并探讨了中间主应力和基质吸力的影响特性。结果表明:中间主应力和基质吸力对非饱和土边坡安全系数的影响显著,安全系数随中间主应力效应和基质吸力的增加而大幅提高;边坡稳定性分析的强度理论效应明显,应重视强度准则的选取、加强基质吸力的监测和稳定控制。 相似文献
133.
Gubarngobarr Gubarndubarz Adnan Deniz 《Polymer-Plastics Technology and Engineering》2013,52(3-4):221-227
Propylene glycol- and diethylene glycol-based unsaturated polyesters were prepared and hardened by using styrene and acrylonitrile monomer mixtures. The addition of 12% acrylonitrile to a propylene glycol-based polyester containing 40% styrene increased the hardness from 12 BHN to 26 BHN. The addition of 20% acrylonitrile increased the impact strength of the same polyester from 14 J/m width to 39 J/m width. The diethylene glycol-based polyester containing 40% styrene and 40% acrylonitrile achieved a hardness of 23 BHN and an impact strength of 59 J/m width. 相似文献
134.
In order to identify the principal factors influencing soil water characteristics (SWC) and evaluate SWC effectively, the multivariate-statistical canonical correlation analysis (CCA) method was used to study and analyze the correlation between SWC and soil physical and chemical properties. Twenty-two soil samples were taken from 11 main tobacco-growing areas in Guizhou Province in China and the soil water characteristic curves (SWCC) and basic physical and chemical properties of the soil samples were determined. The results show that: (1) The soil bulk density, soil total porosity and soil capillary porosity have significant effects on SWC of tobacco fiels. Bulk density and total porosity are positively correlated with soil water retention characteristics (SWRC), and soil capillary porosity is positively correlated with soil water supply characteristics (SWSC). (2) Soil samples from different soil layers at the same soil sampling point show similarity or consistency in SWC. Inadequate soil water supply capability and imbalance between SWRC and SWSC are problems of tobacco soil. (3) The SWC of loamy clay are generally superior to those of silty clay loam. 相似文献
135.
Experience is described for leveling of the tilts of a nine-story tenement building founded on soils prone to slump-type settlement by regular wetting through filtration-weep holes around the building and partially through pits excavated inside the interstitial basement. The leveling was carried out without curtailing the normal service of the building and evacuating its tenants; the building is located in an area classed with an eight-point seismicity.Publicly owned joint-stock company Tsentr Sotsial'noi Ékspertizy 相似文献
136.
137.
Evaluation of iron oxide impregnated filter paper method as an index of phosphorus availability in paddy soils of Tanzania 总被引:1,自引:0,他引:1
Phosphorus is a major yield limiting nutrient in rice production and yet most soil test methods for predicting P availability
to plants have a number of shortcomings especially under flooded conditions. The objective of this study was to evaluate the
iron oxide impregnated filter paper (Pi) method for assessing changes in P availability in soils subsequent to flooding and
to determine the suitability of the method in assessing P status in paddy soils. The results indicated that available P increases
considerably (between 34% and 256%) subsequent to flooding and this affected responsiveness of the soils to P application.
Two versions of the Pi method namely; the Pi method used under flooded conditions (Pi-Pf) and Pi strips embedded directly in flooded soils (Pi-Pfe) were effective in assessing P availability in paddy soils. The two Pi methods were better correlated with rice dry matter
yield than the traditional soil tests and are hence recommended for use in soil testing under flooded conditions. The tentative
critical levels of P for the two procedures under pot conditions were 22 mg/kg for Pi-Pf and 15 mg/strip for Pi-Pef. 相似文献
138.
Experience with use of pile foundations is described for the construction of five-, nine-, and 12-story buildings under complex soil conditions in Georgia with consideration given to the differing seismicity of the regions. Deformations are cited for residential buildings erected on reinforced-concrete friction piles in weak clayey soils, and also buildings on piles situated in soils prone to slump-type settlement. The range of application of pile foundations is presented for these conditions. 相似文献
139.
140.
钴与其它金属的复合物对不饱和聚酯固化的促进作用 总被引:2,自引:0,他引:2
研究了钴与碱金属、碱土金属、过渡金属的复合物地不饱和聚酯树脂固化的促进作用,结果令人满意。 相似文献