降解未处理纤维素厌氧混合菌群的筛选及功能

为获得高效稳定的原木质纤维素降解微生物,利用限制性培养手段,从瘤胃残渣中筛选出了可以体外培养、分解能力强且性能稳定的纤维素厌氧降解菌群FYG-2.该菌群在38.5 ℃,pH6.4～6.8条件下,5 d内可以使1.00 g滤纸完全崩解.转接30代,其降解性能仍保持稳定,且纤维素底物的灭菌与否均不影响其分解.以底物失重率、...     

Fabrication of heterojunction SnO2/BiVO4 composites having enhanced visible light photocatalystic activity

SnO₂/BiVO₄ heterojunction composite photocatalysts with various mole ratios have been prepared via a simple hydrothermal method. The structure, composition and optical properties of the SnO₂/BiVO₄ composites were determined by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) surface analysis, X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectroscopy (UV–vis DRS). Photocatalytic activities of the composites were evaluated by studying the degradation of methylene blue (MB) solutions under simulated visible light irradiation (500 W halogen tungsten lamp). The 3:7 mol ratio SnO₂/BiVO₄ composite exhibited the highest photocatalytic performance, leading to 72% decompositon of MB within 120 min of irradiation.     

A graphene oxide-based molecularly imprinted polymer platform for detecting endocrine disrupting chemicals

A molecularly imprinted polymer-graphene oxide (MIP-GO) hybrid material was synthesized by reversible addition and fragmentation chain transfer (RAFT) polymerization using RAFT agent functionalized GO as chain transfer agent. The formation of this hybrid material was verified by Raman spectroscopy, Fourier transform infrared spectroscopy, and thermal gravimetric analysis. Atomic force microscopy showed that the average thickness of the polymer grafted on the GO surface is about 3.70 nm. The resulting GO-MIP hybrids showed outstanding affinity towards 2,4-dichlorophenol (2,4-DCP) in aqueous solution. The GO-MIP hybrids bind the original template 2,4-DCP with an appreciable selectivity over structurally related compounds. Density functional theory calculations verified the mechanism of the significant improvements on the affinity and selectivity of the MIP-functionalized graphene materials.     

辽宁省水资源利用与社会经济的协调发展量化分析

选取辽宁省锦州市1985-2005年的水资源利用及社会经济发展数据,引入水资源利用与经济社会发展协调系数,通过与美国的对比,为锦州市水资源开发利用与经济社会发展的协调发展提供依据.与此同时,基于陈守煜教授的工程模糊集理论,给出可持续度的定义,并采用模糊隶属度描述可持续度来衡量复杂水资源系统可持续发展水平的评价方法,结合辽宁省水资源利用的实际情况,研究区域水资源可持续利用与经济社会协调发展关系.研究结果表明,目前辽宁省水资源系统可持续发展水平相对较低,尚有较大的开发潜力和提升空间.     

Surfactant-assisted synthesis of platinum nanoparticle catalysts for proton exchange membrane fuel cells

High-performance platinum nanoparticle catalysts (Pt–NPCs) remain the most widespread applied electrocatalysts for oxygen reduction reaction (ORR). Here, cetyltrimethylammonium bromide (CTAB), a surface-controlling agent, is introduced to modulate the microstructure and size of Pt nanoparticles (NPs) via a microwave-assisted heating process. The Pt-NPC assisted by 5 wt% CTAB exhibits the highest mass activity (MA) of 0.072 A mg_Pt^?1 and specific activity (SA) of 0.077 mA cm^?2, higher than those of commercial Pt/C (0.023 A mg_Pt^?1 and 0.035 mA cm^?2). Transmission electron microscopy (TEM) results indicate that Pt NPs are uniformly dispersed onto carbon supports with an average size of 2.39 nm. When applied in membrane electrode assembly (MEA), it exhibits the highest power density of 1.142 W cm^?2, which is about 1.24 times larger than that of commercial Pt/C.     

Decoupling the Voltage Hysteresis of Li-Rich Cathodes: Electrochemical Monitoring,Modulation Anionic Redox Chemistry and Theoretical Verifying

Cathodes in lithium-ion batteries with anionic redox can deliver extraordinarily high specific capacities but also present many issues such as oxygen release, voltage hysteresis, and sluggish kinetics. Identifying problems and developing solutions for these materials are vital for creating high-energy lithium-ion batteries. Herein, the electrochemical and structural monitoring is conducted on lithium-rich cathodes to directly probe the formation processes of larger voltage hysteresis. These results indicate that the charge-compensation properties, structural evolution, and transition metal (TM) ions migration vary from oxidation to reduction process. This leads to huge differences in charge and discharge voltage profile. Meanwhile, the anionic redox processes display a slow kinetics process with large hysteresis (≈0.5 V), compared to fast cationic redox processes without any hysteresis. More importantly, a simple yet effective strategy has been proposed where fine-modulating local oxygen environment by the lithium/oxygen (Li/O) ratio tunes the anionic redox chemistry. This effectively improves its electrochemical properties, including the operating voltage and kinetics. This is also verified by theoretical calculations that adjusting anionic redox chemistry by the Li/O ratio shifts the TM 3d—O 2p bands and the non-bonding O 2p band to a lower energy level, resulting in a higher redox reaction potential.     

Macroporous carbon foam with high conductivity as an efficient anode for microbial fuel cells

In this work, we demonstrate graphitized mesophase pitch-based carbon foam as anode for microbial fuel cells for the first time. Graphitized mesophase pitch-based carbon foam (GMCF), mesophase pitch-based carbon brush (MCB), pitch-based carbon felt (CF) with the different structures are investigated. Among them, GMCF-MFC exhibits excellent power generation property of 1800 mW/m², which is 1.33 and 2.65 times that of MCB-MFC and CF-MFC. GMCF is a graphitized material with a high electrical conductivity that accelerates extracellular electron transport (EET) between microorganisms and the surface of the material, thereby improving the electrochemical performance of MFCs. Besides, GMCF has well-developed macroporous (almost 300 μm in diameter) and through-pore structures, which could facilitate the enrichment of microorganisms and the diffusion of ions. And the staggered through-pores fix exoelectrogens in the pores, preventing them from “swimming out” and promoting the formation of microbial communities in these pores. More importantly, GMCF is a low-cost rigid carbon foam that can be easily fabricated into large-sized electrodes, which is beneficial for application to MFC amplification tests.     

Graphene oxide shell-isolated Ag nanoparticles for surface-enhanced Raman scattering

An efficient surface enhanced Raman scattering (SERS) substrate has been developed based on Ag nanoparticle-decorated graphene oxide (GO). The structure of Ag@GO hybrid material was confirmed by X-ray diffraction, transmission and scanning electron microscopy. The as-prepared substrate exhibited the enhancement ability of SERS toward various aromatic dyes, such as Rhodamine 6G, Rhodamine B, and crystal violet. The enhanced Raman signals could be due to the presence of an ultrathin GO shell with 2.8 nm in thickness. In particular, the GO shell could efficient to maintain chemical and optical stability, and improved biocompatibility for this SERS-activity material.     

Impacts of urban form on air quality in metropolitan areas in the United States

Among 221 metropolitan areas (MAs) in the United States (US), this study explored the impact of urban form, either urban compactness or urban sprawl, on two types of air quality in 2014: NO_x emissions from road traffic and annual average NO2 concentrations. Urban form was quantified using Smart Growth America (SGA) sprawl indexes with density, land use mixing, centeredness, and street connectivity. NO_x emissions from road traffic were derived from the National Emissions Inventory (NEI). Through modeling NO2 concentrations using land use regression (LUR), with satellite-based estimates and kriging, this study measured NO₂ concentrations within MAs in the US The study results showed that higher levels of urban form scores (i.e., higher compactness) and land use mixing were associated with lower per-person NO_x emissions from road traffic. In addition, higher levels of centeredness were associated with lower NO₂ concentrations, but the effect was moderate. On the other hand, regional rainfall and solar insolation had more significant associations with NO₂ concentrations than metropolitan urban form. Meanwhile, localized emissions sources had significant associations with local-level NO₂ concentrations. This study provides additional evidence on the relationship between urban form and air quality in the US MAs. The study suggests that high compactness-oriented development and the reduction of localized emission sources may be effective in reducing NO_x emissions from road traffic and local NO₂ concentrations, respectively. However, future studies need to explore the impact of urban form at both the MA and local levels on NO₂ concentrations and develop a more accurate national NO₂ concentration prediction model.     

MBBR—MBR组合工艺处理生活垃圾沥滤液的研究

室温下,采用缺氧/两级好氧MBBR—MBR组合工艺对厌氧处理后的垃圾焚烧厂沥滤液进行处理。实验结果表明:在进水pH约为7、进水流量1.0 L/d和总回流比400%的条件下,即使沥滤液的NH4+-N高约1 650 mg/L、COD约为6 500 mg/L时,组合工艺对COD、NH4+-N、TN的去除率仍达到80%、99%、81%左右,出水NH4+-N<15mg/L,该工艺能实现对高浓度NH4+-N的有效去除。另外,二级好氧MBBR和MBR中的亚硝氮积累率分别达到90%、80%左右。这两个反应器中亚硝酸菌的数量远多于硝酸菌。