Microbial fuel cell (MFC)-based biosensor for combined heavy metals monitoring and associated bioelectrochemical process

To explore the feasibility and related mechanism of MFC biosensor for wastewater detection under the action of combined heavy metals. Cyclic voltammetry (CV) and scanning electrochemical impedance spectroscopy (EIS) were used to explore the related bioelectrochemical process. The response of the reactor to single/combined heavy metals, low/high heavy metal concentrations, and the differences in ohmic resistance (Rs) and charge transfer resistance (Rct) were investigated using Ni as the core heavy metal and the combined action of Cd, Cu and Zn. The results indicated that there was a linear relationship between the concentration and output voltage of the MFC biosensor under the action of combined heavy metals (R² = 0.8803–0.973). However, the internal resistance (Rint) of the MFC biosensor under the action of single heavy metal was far less than that of the combined heavy metal group, and the power density (19.849 W m^?3) was 4 times that of the combined heavy metal group (3.109–4.589 W m^?3). The Rs of the biosensors in the combined heavy metal group were 0.868Ω and 0.860, which were higher than 0.768Ω of the single heavy metal sensor. With the increase of the concentration of heavy metals in the influent, the increase of Rct was more obvious in the combined group, while the Rs in the single group significantly increased (P < 0.05). The results imply that it is possible for MFC biosensors to be used in the detection of actual water polluted by various heavy metals, but the biosensor performance is mainly limited by Rct, which needs to be further improved.     

Good dielectric performance and broadband dielectric polarization in Ag,Nb co-doped TiO2

Due to the demand of miniaturization and integration for ceramic capacitors in electronic components market, TiO₂-based ceramics with colossal permittivity has become a research hotspot in recent years. In this work, we report that Ag⁺/Nb⁵⁺ co-doped (Ag_1/4Nb_3/4)_xTi_1−xO₂ (ANTOx) ceramics with colossal permittivity over a wide frequency and temperature range were successfully prepared by a traditional solid–state method. Notably, compositions of ANTO0.005 and ANTO0.01 respectively exhibit both low dielectric loss (0.040 and 0.050 at 1 kHz), high dielectric permittivity (9.2 × 10³ and 1.6 × 10⁴ at 1 kHz), and good thermal stability, which satisfy the requirements for the temperature range of application of X9R and X8R ceramic capacitors, respectively. The origin of the dielectric behavior was attributed to five dielectric relaxation phenomena, i.e., localized carriers' hopping, electron–pinned defect–dipoles, interfacial polarization, and oxygen vacancies ionization and diffusion, as suggested by dielectric temperature spectra and valence state analysis via XPS; wherein, electron-pinned defect–dipoles and internal barrier layer capacitance are believed to be the main causes for the giant dielectric permittivity in ANTOx ceramics.     

我国利用水泥窑协同处置污染物的现状及展望

利用水泥窑协同处置污染物可以缓解现阶段的环保压力,且具有良好的社会效益、环保效益及经济效益。文中以水泥窑协同处置为研究对象,探究其在我国的发展历程,并对其未来发展进行展望。     

页岩气开采对环境的影响分析及对策建议

我国页岩气资源非常丰富,但勘探开发难度巨大。分析了页岩气资源大规模开发对水资源、大气环境、地质环境及周边环境产生的影响。提出了需要健全的页岩气开发的环境监管法规规范,只有制定好产业政策,加强对技术和开采原料的研究等,才能促进页岩气产业健康、快速发展,更好地服务于中国和谐社会的建设与发展。     

Up-pulling force analysis for ESC hollow cylindrical casting

Electroslag casting(ESC)is an important method to produce high quality castings.In this study,the ESC up-pulling inner mold method(EUPIM)was used to produce hollow cylindrical castings with the multiple consumable electrodes.The radial deformation,the axial and radial internal stress of the inner mold,and the axial internal stress of the slag shell were analyzed using the finite element method(FEM)with the aid of ANSYS software.The ProCAST software was used to calculate the specific heat,heat conductivity and density curve of Cu.Simulation results show that the radial deformation,the axial and radial internal stress of the inner mold,and the axial internal stress of the slag shell near the slag-metal interface of hollow cylndrical casting gradually increase from 0 s to 360 s after the ESC starting(slagging)process but before applying the up-pulling force.The suitable initial up-pulling moment of the inner mold is at around 180-198 s after the starting process.     

微间隙共形圆柱接触力模型的适用性分析

针对目前间隙铰接副接触力模型无法有效表述不同材料耗散阻尼效应,以及不适用于微间隙共形接触的问题,分析各种接触力模型中弹性接触力和耗散阻尼力计算方法的优缺点,提出一种普适性的圆柱内接触力分析模型。该模型将接触力描述为接触深度的显式函数,并将其适用范围有效地扩展至微间隙和低恢复系数工况。采用含间隙铰接副的曲柄-滑块机构进行动力学分析,对所提出接触力进行验证,计算结果表明:所提出的普适性接触力模型体现了微间隙时更高的接触刚度和低恢复系数时显著的阻尼效应,从而可为不同材料和间隙尺寸的间隙铰接副力学分析提供更为完备的计算模型。     

制浆造纸行业水污染全过程控制技术理论与实践

制浆造纸行业是我国水污染防治的重点,减排任务艰巨。在环境倒逼下,造纸行业加快淘汰落后产能和完善末端治理技术,污染控制取得了初步成效。但随着国家和地方环境治理由浓度控制走向总量控制、质量控制,原有技术的局限性难以满足解决水污染的更高要求,必须创新污染防治方法。本文介绍了制浆造纸行业水污染全过程控制的基本理论和内涵,并结合化学法制浆、化学机械法制浆、废纸制浆与造纸过程水污染防治工程实践,提出了解决制浆造纸行业水污染的对策,为推动行业绿色转型升级和高质量发展提供了支撑。     

Propagation and termination of an internal crack in continuously cast austenitic stainless steel analyzed by ∑ values and the Schmid factor

The formation mechanism of an internal crack was clarified from the viewpoint of the crystallography and thermal expansion. An inverse pole figure map obtained by EBSD pattern showed that the crack propagated along the grain boundaries having high ∑ values within the columnar zone. After the crack initiation, these positions were considered to undergo cracking followed by propagation toward the equiaxed side. Near the termination position, the grains ahead of crack propagation had a Schmid factor higher than 0.45 consuming elastic strain energy. Thermal expansion measurements showed that the grain with (0 0 1) orientation had the largest expansion while that with (0 1 1) the smallest. The grain boundaries neighboring the combination of (0 0 1) and (0 1 1) grains had the largest thermal stress. Therefore, thermal stress contributed to the initiation of cracking. It was thus proposed to enlarge the equiaxed zone to prevent cracking by discontinuing the crack propagation.     

果蔬汁中氯氰菊酯、多效唑、哒螨灵含量测定能力验证结果分析

目的分析果蔬汁中氯氰菊酯、多效唑、哒螨灵含量测定能力验证结果。方法本实验室参加中国检验检疫科学研究院测试评价中心组织的果蔬汁中氯氰菊酯、多效唑、哒螨灵的测定能力验证(ACAS-PT806-2019),根据能力验证作业指导书要求和样品情况,采用了QuEChERS样品前处理净化方案,气相色谱电子捕获检测器检测氯氰菊酯,内标法定量,液相色谱串联质谱检测多效唑和哒螨灵,外标法定量。结果 1号样品中氯氰菊酯、多效唑、哒螨灵残留量分别为0.098、0.043、0.084 mg/kg, 2号样品中氯氰菊酯、多效唑、哒螨灵残留量分别为:0.036、未检出、0.013 mg/kg。所有测定项目结果均为满意(|Z|≤2)。结论实验室解决了此次能力验证中没有空白样品,检测项目基质效应差异明显等难点。实验室农药残留检测能力得到有效验证和提高。