环境友好型多功能海水缓蚀剂的研制及性能研究

为同时解决碳钢与铜材在海水中的腐蚀问题,将聚天冬氨酸、苯并三唑等5种原料按一定的质量比复配成多功能海水缓蚀剂。利用失重法和电化学法研究了海水缓蚀剂在海水中对A3碳钢及H62黄铜的缓蚀性能。结果表明,当海水缓蚀剂用量为150 mg/L时,对碳钢与黄铜在海水中的腐蚀均有良好的抑制作用,碳钢缓蚀率达到95.17%,黄铜缓蚀率达到93.67%。该海水缓蚀剂具有优良的生物降解性能,28 d后生物降解率达到82.6%。     

X70钢的滨海盐渍土-海水宏电池腐蚀

利用电化学阻抗测试技术等,研究了X70钢在滨海盐渍土与海水构成的宏电池中的腐蚀行为。结果表明,构成宏电池之后,海水侧X70钢一直作为宏电池的阳极处于被腐蚀状态,其腐蚀速率为自然腐蚀速率的25.3倍,腐蚀过程主要受阴极反应控制;由于腐蚀产物膜和氯离子的双重作用使宏电池腐蚀速率先有一定程度的降低,然后迅速升高,再有所降低并趋于稳定。试验还发现土壤-海水构成的宏电池的电动势并没有表现出像常规土壤宏电池电动势那样的先升高后降低的趋势,而是先有一定程度的降低,然后迅速升高后趋于稳定,该过程主要受极化电阻的影响。     

砂滤+混凝+超滤组合工艺的海水深度预处理

采用砂滤 混凝 超滤的处理工艺对渤海海水进行了深度预处理.结果表明,组合工艺对海水预处理效果明显,处理后出水浊度可达到1.0NTU以下,CODMn去除率达到了60%以上,出水SDI<3,达到反渗透进水指标.试验表明,砂滤 混凝 超滤组合是一种可行的海水深度预处理工艺.     

壳聚糖在海水混凝处理过程中的助凝作用研究

将天然高分子絮凝剂壳聚糖(CTS)与无机絮凝剂FeCl3协同使用,混凝处理渤海湾近岸海水,考察了壳聚糖投加量、pH值和沉降时间对浊度和其它污染物去除效果的影响。试验结果表明,CTS对FeCl3助凝效果显著,与单独使用FeCl3相比,其浊度、化学耗氧量(CODMn)和总磷(TP)去除率分别提高了8.3%、9.6%和9.4%。FeCl3与CTS协同使用还可明显改善絮体的沉降性能,缩短沉淀时间。综合考虑各项主要技术指标,其海水混凝适宜条件为m(FeCl3)/m(CTS)=15.0。     

反渗透海水淡化旋转式压力能回收装置中液柱活塞的数值模拟研究

旋转式压力能回收装置通过高低压流体直接接触实现能量的交换,而海水浓度变化甚微,实现这一过程的关键是在转子孔道内形成液柱活塞。建立了带有转动影响的二维数学模型,利用计算流体软件对液柱活塞进行模拟．从而分析了液柱活塞的形成过程及其特点。最后,通过线形回归的方法得到关于容积效率的经验公式。探索对装置设计起指导意义的规律。     

Coupled mechanical stress and multi-dimensional CFD analysis for high temperature proton exchange membrane fuel cells (HT-PEMFCs)

We use a combined finite element method (FEM)/computational fluid dynamics (CFD) methodology to numerically investigate the effects of gas diffusion layer (GDL) compression/intrusion on the performance of a phosphoric acid-doped polybenzimidazole (PBI) membrane-based high temperature proton exchange membrane fuel cell (HT-PEMFC). Three-dimensional (3-D) FEM simulations are conducted under various displacement clamping conditions to analyze cell deformation characteristics. Then, a multi-dimensional HT-PEMFC CFD model is applied to the deformed cell geometries to study transport and electrochemical processes during HT-PEMFC operations. Our numerical simulation results reveal that the maximum stresses in the deformed GDLs always occur near the edge of the ribs. The combined effects of GDL compression/intrusion considerably increase spatial non-uniformity in the species and current density distributions, and reduce cell performance.     

钱塘江河口口门段及杭州湾盐度的数值模拟

鉴于钱塘河口和杭州湾潮强流急，总体上属强混合型海域，可以采用计及斜压梯度影响的平面二维盐度方程描述。为适应计算海域所含众多岛屿的复杂平面边界及杭州湾典型的喇叭形态,选用三节点三角形等参元的方法进行数值离散，其中时间导数采用前差，对流项采用迎风格式，二阶项先分部积分处理，空间导数采用与中心差分等价的离散方法。在计算验证中发现，盐度计算的初值必须尽可能恰如其分地给出，可以加速收敛。采用MQ方法插值得到全域各计算点的初值。对盐度计算中的扩散项及盐淡水密度差所致影响等问题进行了讨论。     

Synergy of climate change and local pressures on saltwater intrusion in coastal urban areas: effective adaptation for policy planning

ABSTRACT

This article examines the relative impacts of anthropogenic interventions and global climate change on the dynamics of saltwater intrusion in highly urbanized coastal aquifers. For this purpose, simulations of the impacts of sea-level rise and abstraction scenarios for the near future were undertaken for a pilot aquifer using a multi-objective 3D variable-density flow and solute transport model. We find that sea-level rise associated with climate change has less influence on the encroachment of salinity than anthropogenic abstraction, which has a more appreciable impact on saltwater intrusion through greater sensitivity to water consumption and seasonality.     

多用户并发控制的入侵检测漏警实验系统

利用多种入侵检测躲避技术,采用三层B/S结构,研究并实现了多用户并发控制的入侵检测漏警实验系统,该系统支持多用户并发实验而不相互冲突.对系统的测试以及实践证明,该系统可支持500名左右的用户同时实验并且响应时间不超过3秒.     

QoS Recovery Schemes Based on Differentiated MPLS Services in All-Optical Transport Next Generation Internet

The Internet is evolving from best-effort service toward an integrated or differentiated service framework with quality-of-service (QoS) assurances that are required for new multimedia service applications. Given this increasing demand for high bandwidth Internet with QoS assurances in the coming years, an IP/MPLS-based control plane combined with a wavelength-routed dense wavelength division multiplexing (DWDM) optical network is seen as a very promising approach for the realization of future re-configurable transport networks. Fault and attack survivability issues concerning physical security in a DWDM all-optical transport network (AOTN) require a new approach taking into consideration AOTN physical characteristics. Furthermore, unlike in electronic networks that regenerate signals at every node, attack detection and isolation schemes may not have access to the overhead bits used to transport supervisory information between regenerators or switching sites to perform their functions. This paper presents an analysis of attack and protection problems in an AOTN. Considering this, we propose a framework for QoS guarantees based on the differentiated MPLS service (DMS) model and QoS recovery schemes against QoS degradation caused by devices failures or attack-induced faults in an AOTN. We also suggest how to integrate our attack management model into the NISTs simulator—modeling, evaluation and research of lightwave networks (MERLiN).