苹果梨醋发酵过程中醋酸发酵条件的优化

以甲酚紫培养基中加入乙醇作为分离培养基,从5种水果样品中分离得到20种醋酸菌,然后通过产酸量的测定,筛选出了一株产醋酸度高的醋酸菌AAB13.探讨了乙醇浓度、菌株接种量、发酵液有效体积对醋酸发酵的影响,并在优化的条件下制备了苹果梨醋.     

Bioelectrochemical sulfate reduction enhanced nitrogen removal from industrial wastewater containing ammonia and sulfate

Low organic carbon-to-nitrogen ratio and existing sulfate (SO₄²⁻) in industrial wastewater limited nitrogen removal. Coupling SO₄²⁻ reduction with sulfide autotrophic denitrification provides a novel strategy. Herein, bioelectrochemical sulfate reduction was coupled with heterotrophic sulfate reduction to drive sulfide autotrophic denitrification. In this coupled system, total nitrogen (TN) removal efficiency was increased from ~25% to ~85% by inputting −45 mA electricity. With the help of supplying electrons to denitrification through SO₄²⁻ reduction, coulomb efficiency was improved to 61.5%. Also, bioelectrochemical sulfate reduction could improve sulfur recovery and thus increase TN removal efficiency. Furthermore, through tuning turnover numbers of SO₄²⁻, high TN removal efficiency can be obtained at various concentrations of SO₄²⁻. Moreover, main functional bacteria in this system were identified. Finally, ~75% TN removal efficiency was achieved with real wastewater in this system. Overall, this work offered a new approach for efficient nitrogen removal from industrial wastewater containing SO₄²⁻.     

高级氧化技术降解抗生素及去除耐药性的研究进展

近年来由于抗生素滥用而导致的水污染日益严重,抗生素残留及耐药性已成为当今社会面临的最严峻挑战之一。高级氧化工艺以其快速的反应速率和良好的处理效果,越来越多地被用于治理含抗生素的废水。本文首先阐述了抗生素的污染现状;其后根据起主导作用的自由基种类,分类对比了传统高级氧化和过硫酸盐高级氧化处理抗生素及耐药性的特征,深入分析了过硫酸盐高级氧化的反应机理,重点介绍了热活化、紫外活化、零价铁及其改性活化和电活化等不同活化过硫酸盐的方式,并研究总结了这些技术用于处理抗生素及其耐药性的降解效果和进展;综合分析了目前高级氧化降解抗生素及去除耐药性的环境影响因素和存在的问题;最后对高级氧化的未来发展进行了展望。     

The influence of sulphate-reducing bacteria biofilm on the corrosion of stainless steel AISI 316

This work investigates microbially-influenced corrosion (MIC) of stainless steel AISI 316 by two sulphate-reducing bacteria, Desulfovibrio desulfuricans and a local marine isolate. The biofilm and pit morphology that developed with time were analyzed using atomic force microscopy (AFM). Electrochemical impedance spectroscopy (EIS) results were interpreted with an equivalent circuit to model the physicoelectric characteristics of the electrode/biofilm/solution interface. D. desulfuricans formed one biofilm layer on the metal surface, while the marine isolate formed two layers: a biofilm layer and a ferrous sulfide deposit layer. AFM images corroborated results from the EIS modeling which showed biofilm attachment and subsequent detachment over time.     

油田产出水的腐蚀及防护研究

本文在对长庆油田的靖北、吴旗、油房庄和大水坑区块采油装置发生腐蚀原因分析的基础上,开展了产出水的缓蚀和杀菌试验研究。结果表明,引起井下管柱及集输管线腐蚀的因素主要有产出水矿化度高、H2S和SRB含量高、部分水质溶解氧超标以及井下存在CO2伴生气和不均匀结垢;优选的CI-2缓蚀剂具有较好的缓蚀效果,加量为50mg/L时,可使产出水的腐蚀速度由0.125mm/a降至0.012mm/a,缓蚀率达90%以上;经杀菌剂筛选,BI-2和BI-3对SRB、TGB具有较好的杀菌效果,为了防止产生抗药性,采用BI-2和BI-3交替加药。     

硫酸盐还原菌在不同氧环境下对A3钢腐蚀的研究

通过静态培养实验,研究了在不同的氧环境下,硫酸盐还原菌对A3钢腐蚀的规律。实验结果表明,在相同的培养基中,严格厌氧条件下的硫酸盐还原菌对A3钢的腐蚀速率与连续的厌氧-有氧交替变换条件下的硫酸盐还原菌腐蚀的速率相差不是十分明显。     

硫酸盐还原菌对铜镍合金腐蚀的影响

利用电化学测试技术，在实验室条件下研究了硫酸盐还原菌(SRB)对铜镍合金腐蚀行为的影响。实验结果表明，SRB的存在使电极开路电位明显负移，极化电阻在细菌生长后期迅速降低。在含SRB的溶液中，铜镍合金表面会形成由腐蚀产物和SRB等组成的混合膜，腐蚀速度受到Cu通过混合膜向电极表面扩散速度的控制。     

硫酸盐还原菌对海底土中锌腐蚀的影响

利用微生物分析、交流阻抗测试技术、扫描电镜及表面能谱等方法，在室内模拟条件下研究了海底土中硫酸盐还原菌对锌腐蚀的影响，以及在以接菌及灭菌的海底土构成的宏电池腐蚀中锌的腐蚀行为。180d的试验结果表明：海底土中硫酸盐还原菌增强锌的腐蚀，锌在接菌泥中的平均腐蚀速率及点蚀深度均大于在灭菌泥中的平均腐蚀速率及点饰深度，平均腐蚀速率相差7．0倍，点蚀速率相差15．0倍以上。在接菌和灭菌海底土构成宏电池时，接菌海底土中锌作为阳极，腐蚀速率比自然腐蚀状态下有所增大，加速率为12．7％，而在灭菌海底土中锌作为阴极，腐蚀速率比自然腐蚀状态下有所减小。     

含硫酸盐还原菌土壤中阴极保护对Q235钢腐蚀的影响

利用交流阻抗测试技术、扫描电镜及表面能谱、微生物分析等方法，研究了阴极保护对土壤中Q235钢硫酸盐还原菌腐蚀的影响.30天的实验结果表明，在相同的阴极极化电位下，有菌土壤中Q235钢所需要的阴极极化电流密度均大于灭菌土壤，有菌土壤中Q235钢的平均腐蚀速率均大于灭菌土壤.随着阴极极化电位负移的增大，有菌及灭菌土壤中Q235钢试件周围土壤逐渐呈碱性，有菌土壤中Q235钢试件周围土壤中硫酸盐还原菌数量逐渐减少，当阴极极化电位为-1050 mV时，Q235钢试件周围土壤中硫酸盐还原菌仍能够存活.     

Bacteria foraging optimization in antenna engineering: An application to array fault finding

Finding fault elements in linear antenna arrays using bacteria foraging optimization (BFO) is presented. One of the better options of array diagnosis is to perform it by measuring the radiated field, because in this case, removal of the array from its working site is not required and thereby not interrupting its normal operation. This task of fault finding from far‐field data is designed as an optimization problem where the difference between the far‐field power pattern obtained for a given configuration of failed element(s) and the measured one is minimized w. r. t. the excitations of the array elements. This set of excitations on comparison with the excitations of the original array gives the idea of the fault position and their type, such as either complete fault or partial fault. BFO being relatively new to microwave community when compared with other soft‐computing techniques, its performance was observed w. r. t. time of computation and convergence of the iterative process. Possibility of finding the faults from random sample points and use of minimum number of sample points for array fault finding are the novelties of the present work. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.