Fluxes of dissolved inorganic carbon in three estuarine systems of the Cantabrian Sea (north of Spain)

The diffusive and in situ fluxes of dissolved inorganic carbon (DIC) and total alkalinity (TA) have been measured and an estimation has been made of the water–atmosphere fluxes of CO₂ in three estuarine systems of the Cantabrian Sea during the spring of 1998. Each of these systems undergoes a different anthropogenic influence. The diffusive fluxes of dissolved inorganic carbon and total alkalinity obtained present values ranging between 0.54–2.65 and 0.0–2.4 mmol m⁻² day⁻¹, respectively. These ranges are in agreement with those of other coastal systems. The in situ fluxes are high and extremely variable (35–284 mmol TA m⁻² day⁻¹, 43–554 mmol DIC m⁻² day⁻¹ and 22–261 mmol dissolved oxygen (DO) m⁻² day⁻¹), because the systems studied are very heterogeneous. The values of the ratio of the in situ fluxes of TA and DIC show on average that the rate of dissolution of CaCO₃ is 0.37 times that of organic carbon oxidation. Equally, the interval of variation of the relationship between the benthic fluxes of inorganic carbon and oxygen (F_DIC/F_DO) is very wide (0.3–13.9), which demonstrates the different contributions made by the processes of aerobic and anaerobic degradation of the organic matter, as well as by the dissolution–precipitation of CaCO₃. The water–atmosphere fluxes of CO₂ present a clear dependence on the salinity. The brackish water of these systems (salinity<20), where maximum fluxes of 989 mmol m⁻² day⁻¹ have been estimated, act as a source of CO₂ to the atmosphere. The more saline zones of the estuary (salinity>30) act as a sink of CO₂, with fluxes between −5 and −10 mmol m⁻² day⁻¹.     

察尔汗盐湖路基的灌注法加固及效果分析

在盐湖道路改建工程中，由路基加固前后指标的对比、经济效益分析以及与挤密桩加固法的效果比较，均验证了灌注加固技术是适用于岩盐路基处治的最佳方法。因此，对该方法的研究可为盐湖道路改建工程提供可靠的技术保证。     

含银废弃物中贵金属银综合回收工艺研究进展

贵金属银因具有优异的理化性质,被广泛地应用于工业催化、电子电镀、感光材料等领域。本文综述了含银废弃物中银综合回收工艺的研究现状,分析了火法和湿法回收技术的原理和工艺,介绍了工业上银的溶解方法和还原方法,比较了不同方法的优缺点,并结合工业实例论述了从废银基催化剂、电子废弃物和含银废液中回收银的工艺流程,最后对含银废弃物中银综合回收的前景进行了展望。     

溶岩地区桩基础施工技术问题的探讨

石灰岩地区地质情况较复杂,对桥梁的基础施工带来困难和不利影响。介绍花清高速公路高架桥在石灰岩溶岩地区的桩基础施工技术。     

碳酸盐岩溶蚀实验热力学模型及工程地质意义

开展了碳酸盐岩（灰岩、白云岩）溶蚀作用实验室模拟研究，建立了溶蚀作用的热力学模型方程，对3种不同温压条件下（348．15K，20MPa;373.15K,25MPa；403．15K，30MPa)碳酸盐岩溶蚀作用进行了定量研究，提出了白云岩较灰岩更易溶解并形成孔隙、孔洞等古溶蚀构造，这为油气生成提供了地下空间；同时提出了在城市、铁路及隧道选址等方面充分考虑地下工程地质概貌，以免发生重大的地质灾害及其隐患。     

Modeling gas dissolution in deepwater oil/gas spills

Gases in deepwater oil/gas spills can lose considerable amounts of the gas phase due to dissolution in water. Gas dissolution has a significant impact on the behavior of the oil/gas jet/plume because of its impact on the buoyancy. A method is presented in this paper for computing gas dissolution that covers a broad range of water depth, from shallow water where gases behave as ideal ones under low pressure to deepwater where gases behave as non-ideal ones under high pressures. The method presented also accounts for the spherical and non-spherical shapes of gas bubbles. The gas dissolution computations are validated by comparing the computed results with observed data from previously conducted laboratory experiments. The gas dissolution computation module is then integrated with a model for underwater oil/gas jets/plumes by Yapa and Zheng [J. Hydraul. Res. 35 (5) (1997) 673]. Scenario simulations are presented to show the impacts of gas dissolution on the behavior of jets/plumes. These scenarios show the impact of dissolution on the behavior of the jet/plume. The comparison of results using ideal gas conditions and non-ideal gas conditions is also shown.     

架空裸管冬季输送-5号柴油结蜡溶蜡规律实验

在环境温度较低的冬季输送-5号柴油时,当外界温度低于柴油析蜡点温度时,油品中的蜡晶会析出附着在管壁上,后行油品使其溶解会导致混油段拉长、混油量急剧增加。通过对-5号柴油在低温状态下进行结蜡溶蜡实验,得到-5号柴油在冬季输送时结蜡溶蜡规律。针对南方某石化公司罐区至供销部码头管线的实际情况,分析结蜡溶蜡规律,提出冬季气温低于-5号柴油析蜡点温度时的油品输送方案,为南方某石化公司供销部储运设施及能力整合优化提供依据。     

两种四环素胶囊剂的溶出度及生物利用度的研究

通过对四环素碱胶囊剂和盐酸四环素胶囊剂溶出度及体内生物利用度的测定,表明四环素碱胶囊剂的溶出度低于盐酸四环素胶囊,但在生物利用度方面却优于后者。溶出度和生物利用度之间没有显著相关性。对于四环素碱和盐酸四环素来说,生物利用度不完全取决于溶出度,还与其在体内的吸收特性有关。所以,四环素碱胶囊剂以其价廉、生物利用度高的优点,有着广泛的临床价值。     

Energy principle of corrosion environment accelerating crack propagation during anodic dissolution corrosion fatigue

A general method to predict the crack propagation of anodic dissolution corrosion fatigue is developed in this paper. Crack propagation of corrosion fatigue is presented as the result of the synergistic interactions of mechanical and environmental factors, and corrosive environment accelerates crack propagation mainly in term of anodic dissolution. By studying the variation of mechanical energy and electrochemical energy of anodic dissolution during the crack propagation process, an explicit expression of crack propagation rate is derived by the conservation of energy. The comparisons with experimental data demonstrate the validity of the proposed model. Moreover, the applicable upper-limit crack length for steady crack propagation is determined and the crack propagation life is evaluated.     

甲芬那酸包合物和固体分散体的研究

目的　探索将甲芬那酸 (mefenamicacid ,MFA)制成包合物和固体分散体的工艺 ,以增加其溶解度和溶出速率。方法　采用环糊精 (β CD) ,聚乙二醇 40 0 0 (PEG 40 0 0 )为载体 ,以差示扫描量热图谱与甲芬那酸溶出度为指标 ,确定包合物和固体分散体的制备工艺。结果饱和溶液法制成了甲芬那酸 β CD包合物 ,熔融 冷冻法制成了甲芬那酸 PEG 40 0 0固体分散体 ,甲芬那酸包合物、固体分散体的溶解度分别增加 2 .3、3.1倍。正交试验 9组中以下 3组包合工艺为优 :A3 B3 C2 [m(MFA)∶m(β CD) =1∶8,70℃搅拌 2h],A2 B2 C3 [m(MFA)∶m(β CD) =1∶6 ,6 0℃搅拌 4h],A1B3 C3 [m(MFA)∶m(β CD) =1∶4 ,70℃搅拌 4h]。考虑大规模生产宜选择 β CD用量小、包合效果较好的条件 ,又将A1B3 C3进行扩大试验 ,结果表明该工艺条件重复性好。熔融 冷冻法制备PEG 40 0 0 固体分散体可采用 1∶3～ 1∶4量比。结论　将甲芬那酸制成β CD包合物和PEG 40 0 0 固体分散体技术可行 ,均能显著增加其溶解度和溶出速率