基于中心损失的条件生成式对抗网络的冷水机组故障诊断

针对冷水机组产生的故障数据不足,数据集中正常数据和故障数据数量不平衡,进而导致故障诊断精度下降的问题,提出一种基于中心损失的条件生成式对抗网络(central loss conditional generative adversarial network,CLCGAN)和支持向量机(support vector machine,SVM)的故障诊断方法。首先,CLCGAN利用少量真实故障数据生成新的故障数据;然后,将生成的故障数据与初始数据集混合,使正常数据与故障数据的数量达到平衡;最后,利用平衡数据集构建SVM模型进行故障诊断。在GAN生成冷水机组故障数据时,构建动态中心损失项并加入到目标函数中,利用动态的中心损失减少冷水机组生成的各种故障数据的类内距离,从而降低各个故障生成数据之间的重叠程度,增加生成数据的可靠性。在生成故障数据之前配置相应的故障标签,并输入到CLCGAN中指导数据生成过程,使生成的故障数据可以均衡地分布于各个故障类别。在ASHRAE 1043-RP数据集上对所提方法进行了验证,结果表明,相较于其他解决数据不平衡问题的故障诊断方法,所提方法具有更高的故障诊断准确率。     

基于加权统计特征KICA的故障检测与诊断方法

针对核独立元分析（kernel independent component analysis, KICA）在非线性动态过程中对微小故障检测率低的问题,提出一种基于加权统计特征KICA（weighted statistical feature KICA, WSFKICA）的故障检测与诊断方法。首先,利用KICA从原始数据中捕获独立元数据和残差数据;然后,通过加权统计特征和滑动窗口获取改进统计特征数据集,并由此数据集构建统计量进行故障检测;最后,利用基于变量贡献图的方法进行过程故障诊断。与传统KICA统计量相比,所提方法的统计量对非线性动态过程中的微小故障具有更高的故障检测性能。应用该方法对一个数值例子和田纳西-伊斯曼（Tennessee-Eastman, TE）过程进行仿真测试,仿真结果显示出所提方法相对于独立元分析（ICA）、KICA、核主成分分析（kernel principal component analysis, KPCA）和统计局部核主成分分析（statistical local kernel principal component analysis, SLKPCA）检测的优势。     

基于稀疏局部嵌入深度卷积网络的冷水机组故障诊断方法

针对于冷水机组提出一种基于稀疏局部嵌入深度卷积网络（sparsely local embedding network,SLENet）的故障诊断方法。采用稀疏局部嵌入方法代替卷积核,对输入数据进行特征选择,避免了复杂的训练和调参过程。另外采用空间金字塔最大池化作为网络的输出层,减少了网络的输出维数和分类器的计算量。针对美国采暖、制冷与空调工程师学会提供的冷水机组的典型故障数据进行分类,结果表明,该方法相比深度卷积网络（CNN）和支持向量机（SVM）方法具有更高的故障诊断精度。     

基于稀疏局部嵌入深度卷积网络的冷水机组故障诊断方法

针对于冷水机组提出一种基于稀疏局部嵌入深度卷积网络(sparsely local embedding network,SLENet)的故障诊断方法。采用稀疏局部嵌入方法代替卷积核,对输入数据进行特征选择,避免了复杂的训练和调参过程。另外采用空间金字塔最大池化作为网络的输出层,减少了网络的输出维数和分类器的计算量。针对美国采暖、制冷与空调工程师学会提供的冷水机组的典型故障数据进行分类,结果表明,该方法相比深度卷积网络(CNN)和支持向量机(SVM)方法具有更高的故障诊断精度。     

LDA＿SVM方法在化工过程故障诊断中的应用

针对复杂化工生产过程数据多样性、高维性以及风险重复性的特点,结合网格搜索(GS)与K折交叉验证(K-CV)理论,提出一种基于线性判别分析(LDA)与支持向量机(SVM)相融合的故障诊断方法。首先利用LDA对正常工况和5类故障模式的混合运行数据进行矢量映射,压缩特征空间维度,抽取并重构故障特征信息。将预处理后的数据作为输入样本,利用GS与K-CV得到最佳SVM分类器,实现故障诊断。仿真结果表明,相对于单一SVM和PCA(主元分析)_SVM故障诊断模型,LDA与SVM融合故障诊断方法收敛速度快、诊断准确率高、模型健壮,对化工过程6种运行模式的故障识别准确率达到93.9%。     

基于参数残差驱动贝叶斯网络的冷水机组故障诊断

应用于冷水机组的故障诊断技术对于降低建筑能耗，提高机组运行效率有着重要作用。为了进一步提高冷水机组故障诊断性能，同时考虑到特征参数残差蕴含更多故障信息，提出一种基于特征参数残差驱动贝叶斯网络(BN)的冷水机组故障诊断方法。首先，构建特征参数基准值模型，获得其基准值；然后使用基准值和其实际运行值之间的参数残差训练BN模型。以此达到充分利用参数残差蕴含故障信息，从而提高故障诊断性能的目的。使用实验数据对构建方法的有效性进行验证，与使用特征参数直接驱动BN的诊断模型相比，对冷水机组常见故障的诊断正确率最高提升了约22.51个百分点。此外，比较分析了三种参数基准值模型构建方法的性能，基于神经网络方法的基准值模型较其他两种基准值模型表现更优。     

基于模拟疫苗的人工免疫系统在氯乙烯聚合间歇过程故障诊断中的应用

根据聚氯乙烯工业生产过程的工艺信息、操作规程和历史数据,利用Aspen软件建立了氯乙烯悬浮聚合间歇过程的动态仿真模型,由模拟得到的多个状态的样本数据生成正常模拟疫苗和故障模拟疫苗,结合工业数据建立正常抗体库和故障抗体库,解决了氯乙烯聚合过程故障诊断中故障样本数据缺乏的问题。利用动态时间弯曲算法和人工免疫系统对该聚合反应间歇过程进行故障诊断,具有较好的诊断效果。     

基于重构的半监督ELM及其在故障诊断中的应用

工业过程中获取带标签的故障数据困难,而无标签故障数据却大量存在,如何有效地利用数据信息进行故障诊断是故障诊断领域的重要内容。为更充分地挖掘和利用数据信息,提出一种新的半监督学习方法:基于重构的半监督极限学习机(RSELM)。相比于传统的半监督极限学习机(ELM)方法,RSELM采用自动编码ELM(ELM-AE)获得的输出权重替代随机的隐含层输入权重,能更有效地提取数据特征;考虑到数据均可由其近邻数据来线性重构,故可构建近邻数自适应选择的重构图,并同时利用数据的标签信息优化连接权重,以更优地反映数据结构信息;通过建立新的含局部保持的目标函数,可有效地训练分类器。标准数据集和TE过程上的仿真实验验证了所提算法的有效性。     

基于重构的半监督ELM及其在故障诊断中的应用

工业过程中获取带标签的故障数据困难，而无标签故障数据却大量存在，如何有效地利用数据信息进行故障诊断是故障诊断领域的重要内容。为更充分地挖掘和利用数据信息，提出一种新的半监督学习方法：基于重构的半监督极限学习机（RSELM）。相比于传统的半监督极限学习机（ELM）方法，RSELM采用自动编码ELM（ELM-AE）获得的输出权重替代随机的隐含层输入权重，能更有效地提取数据特征；考虑到数据均可由其近邻数据来线性重构，故可构建近邻数自适应选择的重构图，并同时利用数据的标签信息优化连接权重，以更优地反映数据结构信息；通过建立新的含局部保持的目标函数，可有效地训练分类器。标准数据集和TE过程上的仿真实验验证了所提算法的有效性。     

基于决策分类方法的水泥回转窑故障诊断方法

提出了一种基于决策分类的水泥回转窑故障诊断方法。该方法利用水泥生产过程中产生的回转窑历史数据结合模糊决策树算法生成故障诊断模糊推理规则库,利用在线数据可对模糊规则库进行增量学习,不断完善故障诊断规则库。故障诊断阶段,将在线数据形成的特征向量与故障诊断规则库进行匹配,判断是否发生故障以及相应的故障类型。该方法对故障数据进行模糊化处理,提高了故障诊断结果的可解释性以及泛化性能,适用于实际的水泥生产过程。     

合成生物学方法改造电活性生物膜研究进展

电活性生物膜是由电能细胞分泌的胞外多糖、蛋白、胞外DNA（extracellular DNA, eDNA）、菌毛等成分聚集，与细胞本身相互交联形成的导电多聚体。以多菌群落形态展现，在微生物燃料电池、微生物电合成、高值化学品生产、重金属污染处理、医疗等领域中具有至关重要的作用，是微生物电催化系统研究的核心之一。但自然状态下的电活性生物膜因厚度、结构稳定性、生物量等因素的限制，严重制约了电子传递效率。综述了近五年利用合成生物学改造电活性生物膜的研究进展，系统探讨了工程生物膜的构建、结构成分、导电性能以及应用，为将来进一步实现高效电催化奠定基础。     

An electrochemical impedance model for integrated bacterial biofilms

Bacterial cells attachment onto solid surfaces and the following growth into mature microbial biofilms may result in highly antibiotic resistant biofilms. Such biofilms may be incidentally formed on tissues or implanted devices, or intentionally formed by directed deposition of microbial sensors on whole-cell bio-chip surface. A new method for electrical characterization of the later on-chip microbial biofilm buildup is presented in this paper. Measurement of impedance vs. frequency in the range of 100 mHz to 400 kHz of Escherichia coli cells attachment to indium-tin-oxide-coated electrodes was carried out while using optical microscopy estimating the electrode area coverage. We show that impedance spectroscopy measurements can be interpreted by a simple electrical equivalent model characterizing both attachment and growth of the biofilm. The correlation of extracted equivalent electrical lumped components with the visual biofilm parameters and their dependence on the attachment and growth phases is confirmed.     

促进微生物胞外电子转移的纳米材料研究进展

胞外电子转移（EET）是产电微生物在代谢过程中将自身产生的电子转移到外部电子受体的过程，然而较缓慢的胞外电子转移速率显著影响了微生物燃料电池（MFCs）的产电性能，提高胞外电子转移的效率对推动微生物燃料电池的大规模应用具有重要意义。纳米材料具备优异的导电性、稳定性以及生物相容性，对改善阳极与产电微生物之间的电子传递速率具有重要作用。该文综述了胞外电子转移的主要路径，阐述了不同种类的纳米材料在促进胞外电子转移过程中的机理和其对应的MFCs产电性能，并展望了纳米材料强化微生物EET过程在微生物电化学技术利用方面的研究前景。     

Kinetics of Adhesion Staphylococcus aureus on Glass in the Presence of Sodium Lauryl Sulfate

Bacterial contamination of surfaces is a natural and spontaneous process that often results in the formation of biofilms. The extracellular matrix of biofilm is mostly composed of proteins, polysaccharides, and extracellular DNA and is responsible for the strong persistent ability of biofilm in the food industry. Despite cleaning and disinfection processes, persistent bacteria cause a major problem in food processing environments. Synthetic surfactants, mainly anionic surface-active agent, are commonly used as detergents, foaming agents, wetting agents, emulsifiers, and dispersants. Their tendency to adsorb to surfaces and interfaces and modify their surface tension, is considered among their main properties. They also have the ability to attach to bioactive macromolecules such as proteins, peptides, and DNA causing cell membrane damage. In order to estimate the adhesion kinetic and proliferation of pathogenic bacteria Staphylococcus aureus, the surface of glass was coated with anionic surfactant Sodium Lauryl Sulfate (SLS). Moreover, SLS was added in suspension with the culture medium. The physicochemical properties of the material were calculated using the contact angle measurement method and bacterial hydrophobicity using the microbial adhesion to hydrocarbons (MATH) test. The obtained results showed that the number of adhering cells increased gradually as a function of time. However, changing the surface properties of the glass and S. aureus has affected the rate of adherent cells with time as well as their organization. SLS inhibited the attachment of cells, whether it is added with the microbial suspension or at the surface of the support. Generally, the present article points to a relationship between the microbial adhesion, the surface chemistry of the solid material and the bacteria, and the suspension properties.     

Influence of extracellular polymeric substances on microbial activity and cell hydrophobicity in biofilms

BACKGROUND: Over the last few decades, the emphasis in studies on extracellular polymeric substances (EPS) has been on the extraction and quantitative analysis methods relating to activated sludge. However, little is currently known about the relationship between EPS and microbial activity and cell hydrophobicity in heterogeneous biofilms. This paper aims to reveal the relationship between them. RESULTS: Experimental results indicated that EPS content and components varied with depth in the aerobic biofilter. Protein was the main component of EPS at all depths within the biofilter, and the ratio of protein to polysaccharide was higher in the upper media than that in the lower media. Most active biomass was present in the bottom 25% of the biofilter near the inlet. By means of repeatedly washing intact cells, a sharp decline of EPS content of washed cells was obtained, while active biomass rarely decreased. Microbial activity as well as cell hydrophobicity at different filter depths decreased with the decline of EPS. CONCLUSION: Results indicated that EPS on cell surfaces are essential for microbial metabolism as well as for the formation and stability of biofilm, and it is possible to take EPS into consideration for biofilter control and microbial activity assessment. Copyright © 2007 Society of Chemical Industry     

Cellular Biocatalysts Using Synthetic Genetic Circuits for Prolonged and Durable Enzymatic Activity

Cellular biocatalysts hold great promise for the synthesis of difficult to achieve compounds, such as complex active molecules. Whole-cell biocatalysts can be programmed through genetic circuits to be more efficient, but they suffer from low stability. The catalytic activity of whole cells decays under stressful conditions, such as prolonged incubation times or high temperatures. In nature, microbial communities cope with these conditions by forming biofilm structures. In this study, it is shown that the use of biofilm structures can enhance the stability of whole-cell biocatalysts. We employed two different strategies to increase the stability of whole-cell catalysts and decrease their susceptibility to high temperature. In the first approach, the formation of a biofilm structure is induced by controlling the expression of one of the curli component, CsgA. The alkaline phosphatase (ALP) enzyme was used to monitor the catalytic activity of cells in the biofilm structure. In the second approach, the ALP enzyme was fused to the CsgA curli fiber subunit to utilize the protective properties of the biofilm on enzyme biofilms. Furthermore, an AND logic gate is introduced between the expression of CsgA and ALP by toehold RNA switches and recombinases to enable logical programming of the whole-cell catalyst for biofilm formation and catalytic action with different tools. The study presents viable approaches to engineer a platform for biocatalysis processes.     

低温下磁性载体强化MBBR硝化性能及微生物群落分析

为了增强生物膜耐寒性，提高低温环境下移动床生物膜反应器（MBBR）硝化性能，本文以投加磁性载体构建新型MBBR反应器（R2），同时以投加商用载体作为对照组（R1），在不同温度（14℃±1℃和9℃±1℃）下长期运行，考察了低温下磁性载体对反应器污染物去除性能和生物膜生长特性的影响，并利用高通量测序技术探究了生物膜微生物的响应关系。结果表明：在整个低温运行阶段（0~60天），R2对COD和氨氮去除效果均优于R1。特别在9℃±1℃时，R1和R2出水氨氮平均浓度分别为11.94mg/L、7.60mg/L，R2对氨氮平均去除率比R1提高了16.2%。低温下，磁性载体明显提高了生物膜硝化活性，并促进了胞外聚合物（EPS）分泌，维持和改善了生物膜的形貌结构。高通量测序结果显示，9℃±1℃下不同载体生物膜的微生物群落结构存在显著差异。两种载体的大多数优势属均能降解有机物；磁性载体富集了更多的硝化菌属，其氨氧化细菌（AOB）和亚硝酸盐氧化细菌（NOB）的相对丰度比商用载体分别提高了1.82倍和1.05倍，并且驯化富集了MND1和Candidatus_Nitrotoga 两种特有硝化菌属。从生物膜特性和硝化菌群丰度的角度解释了两个反应器氨氮去除效果的差异性，表明低温下磁性载体MBBR具有更好的硝化性能，可进一步开发应用。     

Characteristics of hydrogen evolution and oxidation catalyzed by Desulfovibrio caledoniensis biofilm on pyrolytic graphite electrode

Hydrogenase, an important electroactive enzyme of sulphate-reducing bacteria (SRB), has been discovered having the capacity to connect its activity to solid electrodes by catalyzing hydrogen evolution and oxidation. However, little attention has been paid to similar electroactive characteristics of SRB. In this study, the electroactivities of pyrolytic graphite electrode (PGE) coated with SRB biofilm were investigated. Two corresponding redox peaks were observed by cyclic voltammetry detection, which were related to the hydrogen evolution and oxidation. Moreover, the overpotential for the reactions decreased by about 0.2 V in the presence of the SRB biofilm. When the PGE coated with the SRB biofilm was polarized at 0.24 V (vs. SHE), an oxidation current related to the hydrogen oxidation was found. The SRB biofilm was able to obtain electrons from the −0.61 V (vs. SHE) polarized PGE to form hydrogen, and the electron transfer resistance also decreased with the formation of SRB biofilm, as measured by the non-destructive electrochemical impendence spectroscopy detection. It was concluded that the hydrogen evolution and oxidation was an important way for the electron transfer between SRB biofilm and solid electrode in anaerobic environment.     

生物基化学品的微生物电合成研究进展

微生物电合成是结合微生物学与电化学的新兴研究方向。电化学活性菌株以直接或间接的方式吸收人工提供的外源电子,打破胞内代谢原有的氧化还原平衡,定向催化底物合成还原性目的产物。近年来,基于生物基化学品的微生物电合成取得广泛关注。本文综述了生物基化学品微生物电合成的基本原理及最新研究进展,并讨论了电化学活性菌株的种类、电子传递机制以及典型的菌株培养方式,同时结合菌株代谢途径,讨论了微生物电合成促进乙酸、1,3-丙二醇、丁醇、琥珀酸等生物基化学品的作用机理及研究现状。最后指出了电子传递机制、电子传递效率及成本是限制该技术发展的关键问题及未来的发展趋势,旨在推动该技术应用于生物基化学品的发酵工业中。