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81.
新型珊瑚海水混凝土力学性能试验研究 总被引:2,自引:1,他引:1
为了解决全珊瑚海水混凝土(coral aggregate seawater concrete,简称CASC)的脆性问题,采用碱式硫酸镁水泥(basic magnesium sulfate cement,简称BMSC)为胶凝材料和剑麻纤维为增韧材料制备了一种新型全珊瑚海水混凝土(NCASC),系统测定了基本力学性能,并与普通硅酸盐水泥制备的CASC、碱式硫酸镁水泥砂石混凝土(basic magnesium sulfate cement concrete,简称BMSCC)、普通砂石混凝土(ordinary portland cement concrete,简称OPC)以及普通轻骨料混凝土(lightweight aggregate concrete,简称LAC)的力学性能进行对比。结果表明:立方体抗压强度(f_(cu),m)在15~35 MPa范围内的NCASC的轴心抗压强度(f_c,m)、劈裂抗拉强度(f_(sp),m)与f_(cu),m之间具有较显著的线性关系;对于f_(cu),m为15~35 MPa的混凝土,相同强度NCASC的f_c,m高于OPC、LAC及BMSCC,其f_c,m与f_(cu),m比值最大,大致在0.85~0.96之间,NCASC的f_(sp),m比OPC和LAC高,但比BMSCC低,且随着强度的提高,OPC与NCASC的f_(sp),m间的差距在增大,而LAC和BMSCC与NCASC的f_(sp),m间的差距在缩小;在强度等级C15~C55的范围中,NCASC和CASC的f_(sp),m、f_c,m与f_(cu),m之间的关系基本可以采用相同的线性回归方程来描述,利用这两个回归线性方程得到对应于标准强度等级的CASC和NCASC的f_(sp),m和f_c,m数据,为CASC力学性能研究与结构设计提供参考依据。 相似文献
82.
83.
热化学硫酸盐还原作用对碳酸盐岩气藏的化学改造——以川东北地区长兴组-飞仙关组气藏为例 总被引:20,自引:0,他引:20
目前在川东北地区长兴组—飞仙关组已发现普光、渡口河、铁山坡、罗家寨等多个高含H2S的大、中型气田。通过天然气地球化学特征、流体包裹体盐度和岩心及薄片的镜下详细观察后认为,川东北地区长兴组—飞仙关组的大多数气藏遭受了热化学硫酸盐还原作用(TSR)的化学改造,TSR的改造主要表现在3个方面:1使C2 重烃相对于CH4、12C相对于13C优先被消耗,造成天然气干燥系数变大和碳同位素变重;2由于TSR产生的大量淡水的加入,使气藏的原生地层水被稀释,造成地层水盐度降低;3TSR相关流体(烃类和H2S等)与储层岩石之间的相互作用使储层被溶蚀和硬石膏发生蚀变,造成储层孔隙度增大,从而对改善其物性具有重要意义。 相似文献
84.
Dissolved inorganic carbon (DIC) and its carbon isotopic composition in sediment pore waters from the Shenhu area,northern South China Sea 总被引:2,自引:0,他引:2
Tao Yang Shao-Yong Jiang Jing-Hong Yang Ge Lu Neng-You Wu Jian Liu Dao-Hua Chen 《Journal of Oceanography》2008,64(2):303-310
The Shenhu area is one of the most favorable places for the occurrence of gas hydrates in the northern continental slope of
the South China Sea. Pore water samples were collected in two piston cores (SH-A and SH-B) from this area, and the concentrations
of sulfate and dissolved inorganic carbon (DIC) and its carbon isotopic composition were measured. The data revealed large
DIC variations and very negative δ
13C-DIC values. Two reaction zones, 0–3 mbsf and below 3 mbsf, are identified in the sediment system. At site SH-A, the upper
zone (0–3 mbsf) shows relatively constant sulfate and DIC concentrations and δ
13C-DIC values, possibly due to bioturbation and fluid advection. The lower zone (below 3 mbsf) displays good linear gradients
for sulfate and DIC concentrations, and δ
13C-DIC values. At site SH-B, both zones show linear gradients, but the decreasing gradients for δ
13C-DIC and SO4
2− in the lower zone below 3 mbsf are greater than those from the upper zone, 0–3 mbsf. The calculated sulfate-methane interface
(SMI) depths of the two cores are 10.0 m and 11.1 m, respectively. The depth profiles of both DIC and δ
13C-DIC showed similar characteristics as those in other gas hydrate locations in the world oceans, such as the Blake Ridge.
Overall, our results indicate an anaerobic methane oxidation (AMO) process in the sediments with large methane flux from depth
in the studied area, which might be linked to the formation of gas hydrates in this area. 相似文献
85.
Marianne Holmer Ole Pedersen Dorte Krause-Jensen Birgit Olesen Malene Hedegrd Petersen Stephanie Schopmeyer Marguerite Koch Bente Aa. Lomstein Henning S. Jensen 《Estuarine, Coastal and Shelf Science》2009,85(2):319-326
Sulfur and oxygen dynamics in the seagrasses Thalassia testudinum and Syringodium filiforme and their sediments were studied in the US Virgin Islands (USVI) in order to explore sulfide intrusion into tropical seagrasses. Four study sites were selected based on the iron concentration in sediments and on proximity to anthropogenic nutrient sources. Meadow characteristics (shoot density, above- and below-ground biomass, nutrient content) were sampled along with sediment biogeochemistry. Sulfide intrusion was high in T. testudinum, as up to 96% of total sulfur in the plant was derived from sediment-derived sulfides. The sulfide intrusion was negatively correlated to the turnover of sulfides in the sediments regulated by both plant parameters and sediment sulfur pools. Sediment iron content played an indirect role by affecting sulfide turnover rates. Leaf production was negatively correlated with sulfide intrusion suggesting that active growth reduced sulfide intrusion. Sulfide intrusion was lower in S. filiforme (up to 44%) compared to T. testudinum consistent with a higher internal nighttime oxygen concentrations found for S. filiforme. When S. filiforme can take advantage of its ability to maintain high internal oxygen concentrations, as was the case on the USVI, it could increase its success in colonizing unvegetated disturbed sediments with potentially high sulfide concentrations. 相似文献
86.
利用硫酸镁和造纸草浆黑液制备含镁氧化合物的吸附剂,通过化学分析、表面性质分析、X射线衍射和红外光谱等对吸附剂进行了表征.考察了吸附剂焙烧温度、投加量、吸附时间以及pH值等因素对活性黄ST-4RFN吸附性能的影响,吸附过程可用Freundlich模型来描述. 相似文献
87.
88.
离子色谱法同时测定地质样品中氟氯磷硫 总被引:5,自引:0,他引:5
本文研究了离子色谱同时测定地质样品中F~-、Cl~-、PO_4~(3-)、SO_4~(2-)的前处理过程,选择了色谱测定最佳条件。在Na_2CO_3全熔的样品溶液中,加入(NH_4)_2CO_3使Si、Al随大多数金属离子同时沉淀;再用预处理柱除去熔剂引入的大量Na~+及CO_3~(2-)消除其干扰;并在流出液中补加相应试剂与淋洗液相匹配,实现了多种地质样品中F~-、Cl~-、PO_4~(3-)和SO_4~(2-)的测定。方法检出限(3s,μg/ml)分别为F~-0.05、Cl~-0.1、PO_4~(3-)0.3、SO_4~(2-)0.5。测定范围为F~-0.05—3μg/ml,Cl~-0.1—6μg/ml,PO_4~(3-)0.3 —30μg/ml,SO_4~(2-)0.5—30μg/ml。 相似文献
89.
黔中茶店桥地下河流域不同水体硫酸盐浓度特征及来源识别 总被引:8,自引:0,他引:8
茶店桥地下河位于西南岩溶区,流域内"三水"转换迅速,地下水是当地的重要饮用水源。本文对流域内雨水、地表水、地下水中的SO_4~(2-)浓度进行了测试,利用氘(δD_(H_2O))、氧(δ~(18) O_(H_2O))同位素示踪地表水、地下水补给来源,用硫酸盐硫(δ~(34)S_(SO4))、氧(δ~(18) O_(SO4))同位素探讨了地表水、地下水中SO_4~(2-)的来源,并计算了地下河出口河水中不同SO_4~(2-)来源的贡献比例。结果表明:1不同水体中SO_4~(2-)浓度大小顺序为地表水地下水雨水,与邻近区域相比,茶店桥地下河流域雨水、地表水、地下水呈现富集SO_4~(2-)的特征。2地表水、地下水的主要补给来源为大气降水,硫酸不仅和HCO_3~-共同参与了流域内碳酸盐岩的溶解,也参与了雨水中含钙镁颗粒物的溶解。3地表水δ~(34)S_(SO4)、δ~(18) O_(SO4)值分别介于-12.98‰~-10.19‰和-0.54‰~+9.13‰之间,地下水δ~(34)S_(SO4)、δ~(18) O_(SO4)值分别介于-14.32‰~+16.58‰和+2.81‰~+14.35‰之间,SW02的SO_4~(2-)主要来源于大气降水,SW01、SW03、GW02、GW03、GW06主要来源于煤层,GW05主要来源于石膏,GW01、GW04为混合输入源。4地下河出口河水中大气降水带来的SO_4~(2-)贡献比例为13%,煤层硫化物氧化的贡献比例为40%,石膏溶解的贡献比例为47%。 相似文献
90.
In this paper,the RIEMS 2.0 model,source emission in 2006 and 2010 are used to simulate the distributions and radiative effects of different anthropogenic aerosols over China.The comparison between the results forced by source emissions in 2006 and 2010 also reveals the sensitivity of the radiative effects to source emission.The results are shown as follows:(1) Compared with those in 2006,the annual average surface concentration of sulfate in 2010 decreased over central and eastern China with a range of-5 to 0 μg/m~3;the decrease of annual average aerosol optical depth of sulfate over East China varied from 0.04 to 0.08;the annual average surface concentrations of BC,OC and nitrate increased over central and eastern China with maximums of 10.90,11.52 and 12.50μg/m~3,respectively;the annual aerosol optical depths of BC,OC and nitrate increased over some areas of East China with extremes of 0.006,0.007 and 0.008,respectively.(2)For the regional average results in 2010,the radiative forcings of sulfate,BC,OC,nitrate and their total net radiative forcing at the top of the atmosphere over central and eastern China were-0.64,0.29,-0.41,-0.33 and-1.1 W/m~2,respectively.Compared with those in 2006,the radiative forcings of BC and OC in 2010 were both enhanced,while that of sulfate and the net radiative forcing were both weakened over East China mostly.(3)The reduction of the cooling effect of sulfate in 2010 produced a warmer surface air temperature over central and eastern China;the maximum value was 0.25 K.The cooling effect of nitrate was also slightly weakened.The warming effect of BC was enhanced over most of the areas in China,while the cooling effect of OC was enhanced over the similar area,particularly the area between Yangtze and Huanghe Rivers.The net radiative effect of the four anthropogenic aerosols generated the annual average reduction and the maximum reduction were-0.096 and-0.285 K,respectively,for the surface temperature in 2006,while in 2010 they were-0.063 and-0.256 K,respectively.In summary,the change in source emission lowered the cooling effect of anthropogenic aerosols,mainly because of the enhanced warming effect of BC and weakened cooling effect of scattering aerosols. 相似文献