Dynamic load-altering attack detection based on adaptive fading Kalman filter in power systems

This paper presents an effective and feasible method for detecting dynamic load-altering attacks (D-LAAs) in a smart grid. First, a smart grid discrete system model is established in view of D-LAAs. Second, an adaptive fading Kalman filter (AFKF) is designed for estimating the state of the smart grid. The AFKF can completely filter out the Gaussian noise of the power system, and obtain a more accurate state change curve (including consideration of the attack). A Euclidean distance ratio detection algorithm based on the AFKF is proposed for detecting D-LAAs. Amplifying imperceptible D-LAAs through the new Euclidean distance ratio improves the D-LAA detection sensitivity, especially for very weak D-LAA attacks. Finally, the feasibility and effectiveness of the Euclidean distance ratio detection algorithm are verified based on simulations.     

高铁酸盐-亚硫酸盐体系氧化降解水中污染物阿特拉津

针对目前日益严峻的农药污染问题，本文以阿特拉津（ATZ）为目标污染物，利用高铁酸盐活化亚硫酸盐的方式对其进行降解。探究了亚硫酸盐浓度、高铁酸盐浓度、ATZ浓度、pH以及亚硫酸盐投加方式对ATZ去除率的影响。研究结果表明，在pH为7、高铁酸盐浓度为100μmol/L、亚硫酸盐浓度为400μmol/L、ATZ的浓度为5μmol/L的条件下，10s时间内可以去除95%的ATZ。利用自由基淬灭实验对体系中的活性物质进行鉴定，结果表明，高铁酸盐-亚硫酸盐体系中起主要作用的是硫酸根自由基（SO{}_{\mathrm{4}}^{·-}），其对ATZ降解的贡献约占53%；其次是羟基自由基（·OH），约占36%。通过改变亚硫酸盐投加方式，减少了SO{}_{\mathrm{4}}^{·-}的自我消耗，提高了高铁酸盐-亚硫酸盐降解ATZ的效率。这些实验结果有助于高铁酸盐-亚硫酸盐体系的实际水处理应用。     

Techno-economic analysis of hydrogen energy for renewable energy power smoothing

With the increasing proportion of renewable energy (mainly wind power and photovoltaic) connected to the grid, the fluctuation of renewable energy power brings great challenges to the safe and reliable operation of power grid. As a clean, low-carbon secondary energy, hydrogen energy is applied in renewable energy (mainly wind power and photovoltaic) grid-connected power smoothing, which opens up a new way of coupling hydrogen storage energy with renewable energy. This paper focuses on the optimization of capacity of electrolyzers and fuel cells and the analysis of system economy in the process of power output smoothing of wind/photovoltaic coupled hydrogen energy grid-connected system. Based on the complementary characteristics of particle swarm optimization (PSO) and chemical reaction optimization algorithm (CROA), a particle swarm optimization-chemical reaction optimization algorithm (PSO-CROA) are proposed. Aiming at maximizing system profit, the capacity of electrolyzers and fuel cells are constrained by wind power fluctuation, and considering environmental benefits, government subsidies and time value of funds, the objective function and its constraints are established. According to the simulation analysis, by comparing the calculated results with PSO and CROA, it shows that PSO-CROA effectively evaluates the economy of the system, and optimizes the optimal capacity of the electrolyzers and fuel cells. The conclusion of this paper is of great significance for the application of hydrogen energy storage in the evaluation of power smoothness and economy of renewable energy grid connection and the calculation of economic allocation of hydrogen energy storage capacity.     

铁碳微电解处理印染废水的效能及机理研究

针对印染废水色度高、成分复杂、难降解等问题，利用铁碳微电解工艺处理该废水，提高其可生化性和处理效率。考察初始pH、铁投加量、铁/碳质量比及反应时间对工艺的影响，通过扫描电子显微镜（SEM）、红外光谱、X射线能谱（EDS）及X射线衍射（XRD）分析反应前后铁碳结构的变化，采用Zeta电位和紫外可见光谱等对比废水处理前后有机物成分的变化，探究印染废水的降解机理。结果表明：在初始pH为4、铁投加量为80 g/L、铁/碳质量比为0.8及反应时间为90 min时，COD、浊度、色度、氨氮和TOC去除率分别为75.48%、87.88%、75.34%、92.01%和81.09%。反应前铁碳反应器的成分以Fe、C为主，活性炭的孔隙结构发达，反应后铁碳表面附着Al、K等其他金属物质和铁的氢氧化物絮体。铁碳微电解工艺可降解酯、醇类有机物为小分子物质，提高废水可生化性。     

高分子絮凝剂处理高浓度化妆品原料生产废水研究

化妆品原料生产过程中产生的废水水质成分复杂、有机物含量高、难降解，利用混凝工艺处理该废水能够减缓生化处理单元的负担，提高污水处理效率。为揭示无机高分子混凝剂混凝过程中污染物的去除机制和污泥性质的变化，考察了不同的絮凝剂聚合氯化铝（PAC）、聚合硫酸铁（PFS）、聚合氯化铝铁（PAFC）和助凝剂聚丙烯酰胺（PAM）投加浓度对污染物去除率和污泥性质的影响。采用傅里叶变换红外光谱（FTIR）、X射线能谱（EDX）、扫描电镜（SEM）、热重分析仪（TGA）分析污泥絮体官能团、表面形貌、元素组成和热稳定性的变化，采用三维荧光光谱（3D-EEM）和超滤技术分析出水中有机物分子量的分布规律和有机物成分的变化，优化最佳混凝工艺运行条件。结果表明：进水中的天然有机物（NOM）荧光强度高，有机物分子量主要分布在>100×10³和<3×10³区间，其所占比例分别为22.89%和50.57%。当进水COD为6700~7500 mg/L时，在助凝剂PAM投加浓度为0.03 g/L，PAC、PFS和PAFC投加浓度分别为2.8 g/L、2.8 g/L和3.0 g/L的条件下，COD去除率分别为87.20%、79.89%和83.74%，出水浊度分别为2.54 NTU、9.3 NTU和5.51 NTU，NOM荧光强度大大减弱。其中，PAC+PAM对废水中有机物去除效果最好，出水有机物分子量主要分布在(10~30)×10³和<3×10³范围内，其所占比例分别为31.84%和25.92%，形成的混凝污泥具有较好的热稳定性，污泥表面蓬松,呈多孔网状结构。混凝工艺可吸附脂类大分子物质，提高了高浓度化妆品原料生产废水的可生化性。     

PMU based voltage security assessment of power systems exploiting principal component analysis and decision trees

The need for feature selection and dimension reduction is felt as a fundamental step in security assessment of large power systems in which the number of features representing the state of power grids dramatically increases. These large amounts of attributes are not proper to be used for computational intelligence (CI) techniques as inputs, because it may lead to a time consuming procedure with insufficient results and they are not suitable for on-line purposes and updates.This paper proposes a combined method for an online voltage security assessment in which the dimension of the token data from phasor measurement units (PMUs) is reduced by principal component analysis (PCA). Then, the features with different stability indices are put into several categories and feature selection is done by correlation analysis in each category. These selected features are then given to decision trees (DTs) for classification and security assessment of power systems.The method is applied to 39-bus test system and a part of Iran power grid. It is seen from the results that the DTs with reduced data have simpler splitting rules, better performance in saving time, reasonable DT error and they are more suitable for constant updates.     

High efficiency photocatalytic CO2 reduction realized by Ca2+ and HDMP group Co-modified graphitic carbon nitride

The development of highly efficient and visible-light responsive carbon nitride (CN) photocatalysts is desirable to address energy shortages and environmental pollution challenges. Herein, we synthesized novel 2-hydroxy-4,6-dimethylpyrimidine (HDMP) group and Ca²⁺ co-modified carbon nitride (CN) photocatalyst (CN-CAA) using a facile in situ copolymerization procedure employing urea and calcium acetylacetonate (CAA) as precursors. The HDMP group and Ca²⁺ co-modification contributed to increased electron density and modulated electronic structure, resulting in extended visible light harvesting and accelerated separation and migration of photoinduced charge carriers. Benefiting from the enhanced visible light utilization and improved photoexcited carriers separation and transportation, the CN-CAA exhibited significantly elevated visible-light-driven photocatalytic activity for CO₂ reduction. This work provided a new insight into the photocatalytic performance promotion of CN through molecular engineering and metal ions incorporation co-modification.     

城市低碳群体建筑外部边缘空间规划仿真研究

针对当前空间规划方法存在的计算时间长、规划成本高等问题,提出一种基于蚁群算法的低碳群体建筑外部边缘空间规划方法。依据城市低碳群体建筑外部边缘空间的模糊特性,引入模糊集合理论对建筑外部边缘空间进行理解和建筑外部边缘空间模糊矩阵的构建,对边缘空间进行划分和限定。结合建筑外部边缘空间的特性和具体关系模式进行空间层次划分,计算空间属性权重,以此确立空间规划目标,根据空间规划目标函数构建空间规划模型,设定求解空间规划模型的蚁群算法信息素更新方式,依据个体信息素转移概率指导个体进行模型最优解搜索。实验结果表明,所提方法与传统的空间规划方法相比,有效减少了计算时间,降低了规划成本。