Plasmonic regulation introduced by metallic nanoparticles is a useful method to improve the detection performance of plasmon-based systems. Herein, we observed a unique enhancement of surface plasmon-coupled emission (SPCE) using plate-shaped plasmonic nanostructures. By assembling Au nanoplates (Au NPLs) via electrostatic adsorption between the Au nanofilm and the quantum dot (QD) layer (630 nm), the fluorescence signal of SPCE was enhanced 90 times more than that of normal SPCE after the conditions were optimized. This enhancement was mainly induced by the intense localized electromagnetic field at the tip of Au NPLs and a novel plasmonic distribution around the "hot-spot" structure between the nanoparticle and Au nanofilm. These effectively mitigated the inherent signal quenching of SPCE and enhanced the emission signal of ultrathin samples on the surface of the NPL-modified Au nanofilm structure. This strategy can be used to improve the detection sensitivity and information integrity of SPCE-based biosensing and bioimaging systems containing ultrathin luminous layers. The different enhancement efficiencies for multiwavelengths were successfully obtained through various emission angles in light of the wavelength resolution of SPCE, thus verifying the existence and importance of energy-matching coupling, and the emission for the fluorophore with low excitation efficiency could also be detected. Benefiting from this, the Au NPL-modulated SPCE system could be a candidate for simultaneous multiwavelength enhancement and high-throughput detection in multicomponent analysis.

教材在教育教学工作中占有非常重要的地位.在系统分析2019人教版高中化学必修教材各栏目的过程中,发现该教材蕴含着丰富的劳动教育资源,经过进一步挖掘和整理,可归纳为认知、实践和价值三个层面;基于ADDIE教学设计模型提出化学教学中劳动教育资源的应用思路,并以"化学能转化为电能——原电池装置"为例进行教学设计.劳动教育与化学教育的深度融合,不仅可以增进学生对化学科学的理解和兴趣,还可以帮助学生树立正确的劳动观,落实"五育"并举的教育方针.

Surface plasmon coupled emission (SPCE), a novel surface-enhanced fluorescence technique, can generate directional and amplified radiation by the intense interaction between fluorophores and surface plasmons (SPs) of metallic nanofilms. For plasmon-based optical systems, the strong interaction between localized and propagating SPs and “hot spot” structures show great potential to significantly improve the electromagnetic (EM) field and modulate optical properties. Au nanobipyramids (NBPs) with two sharp apexes to enhance and restrict the EM field were introduced through electrostatic adsorption to achieve a mediated fluorescence system, and the emission signal enhancement was realized by factors over 60 compared with the normal SPCE. It has been demonstrated that the intense EM field produced by the NBPs assembly is what triggered the unique enhancement of SPCE by Au NBPs, which effectively overcomes the inherent signal quenching of SPCE for ultrathin sample detection. This remarkable enhanced strategy offers the chance to improve the detection sensitivity for plasmon-based biosensing and detection systems, and expand the range of applications for SPCE in bioimaging with more comprehensive and detailed information acquisition. The enhancement efficiency for various emission wavelengths was investigated in light of the wavelength resolution of SPCE, and it was discovered that enhanced emission for multi-wavelength could be successfully detected through the different emission angles due to the angular displacement caused by wavelength change. Benefit from this, the Au NBP modulated SPCE system was employed for multi-wavelength simultaneous enhancement detection under a single collection angle, which could broaden the application of SPCE in simultaneous sensing and imaging for multi-analytes, and expected to be used for high throughput detection of multi-component analysis.

Bacterial infections have become a considerable obstacle to public health due to the emergence of antibiotic resistance. Herein, we rationally developed a novel and attractive nitrogen-doped carbon nanodots (N-CNDs) as efficient metal-free artificial nanozymes that synergistically and efficiently inhibit bacterial survival by inheriting the bacteriostatic ability of tea polyphenols and light-triggered oxidase-like catalytic activity. The excellent oxidase-mimicking activity exhibited by N-CNDs in the light was mediated by superoxide radicals (center dot O-2(-)) with a high maximum reaction rate (1.59 mu M center dot s(-1)) and a low Michaelis constant (0.421 mM). Furthermore, the constructed N-CNDs-based nanozyme was demonstrated to serve as a complex biomaterial platform for efficient sterilization by light-driven oxygen molecule generation of center dot O-2(-). Remarkably, the inherent antibacterial ability of N-CNDs can effectively inhibit both Gram-positive and Gram-negative bacteria, particularly against Grampositive S. aureus at a minimum inhibitory concentration (MIC90) of 375 mu g center dot mL(-1). The inactivation rates of N-CNDs alone agsinst E. coli and S. aureus were 59.72% and 37.15%, respectively. However, the inactivation rates of E. coli and S. aureus by N-CNDs achieved by light were as high as 97.91% and 80.02%, respectively. Encouragingly, a two-way ANOVA revealed that the concentration of N-CNDs and the duration of light exposure had a synergistic effect on antibacterial behavior, which provided favorable conditions for the sustained eradication of exposed bacteria. This synergistic strategy for bacterial eradication based on a novel metal-free carbon-based nanozyme provides a powerful and feasible approach for bacterial contamination management in food safety and environmental protection.

中学化学教学实践发现,电子守恒用于氧化还原反应方程式配平的教学环节,对于学生牢固掌握氧化还原反应方程式配平具有非常重要的意义.在实际的操作过程中,基于守恒观念的历史演化过程,逐步演绎出电子守恒的概念,并针对电子守恒法在教学过程中难以操作的客观事实,借鉴中文表达的音形意统一性原则,对氧化还原反应方程式配平进行格律化的推荐,有较强的理论指导意义和应用价值.

基于学生在学习彼此割裂的化学平衡移动三判据时存在明显的学困现象,针对吉布斯自由能变化ΔG与化学平衡常数K与浓度商Q的定量比较在当前课堂教学中等价性证明的欠缺,对吉布斯自由能变化与化学平衡常数的关系进行了数学推导.该推导解决了吉布斯自由能变化作为化学平衡移动的判据在课堂教学中过于突兀呈现的问题,为学生追求化学中蕴含的数学美提供了示范.

通过水热法合成了一系列MoS2/GQDs复合材料,并制成碳基复合电极.利用电化学测试手段挑选出最佳电极后用于微生物电解池(MEC)阴极的产氢性能研究.实验结果显示:Na2MoO4,半胱氨酸和GQDs的最佳原料配比为375∶600∶1,制备出的MoS2/GQDs呈现明显的爆米花样纳米片结构,片层厚度在10 nm左右,当碳纸负载量为1.5 mg· cm2时,MoS2/GQDs碳纸电极的析氢催化能力最佳.在MEC产氢实验中,MoS2/GQDs阴极MEC的产气量、氢气产率、库仑效率、整体氢气回收率、阴极氢气回收率、电能回收率和整体能量回收率分别为51.15±3.15 mL· cycle-1、0.401±0.032m3H2·m3d-1、91.16±0.054％、66.64±5.39％、72.44±2.60％、217.26±7.42％和77.37±1.50％,均略高于Pt/C阴极MEC或与之媲美.另外,MoS2/GQDs具有良好的长期稳定性,且价格便宜,有利于实际应用.

Surface plasmon coupled emission (SPCE) is a new analytical technique that provides increased and directional radiation based on the near-field interaction between fluorophores and surface plasmons but suffers from the limitation of insufficient sensitivity. The assembly of hollow-porous plasmonic nanoparticles could be the qualified candidate. After the introduction of gold nanocages (AuNCs), fluorescence signal enhancement was realized by factors over 150 and 600 compared with the normal SPCE and free space emission, respectively, with a fluorophore layer thickness of approximately 10 nm; hence, the unique enhancement of SPCE by the AuNCs effectively overcomes the signal quenching induced by resonance energy transfer (in normal SPCE). This enhancement was proven to be triggered by the superior wavelength match, the enhanced electromagnetic field, and new radiation channel and process induced by the AuNC assembly, which provides an opportunity to increase the detection sensitivity and establish an optimal plasmonic enhancement system. The amplified SPCE system was employed for multiwavelength simultaneous enhancement detection through the assembly of mixed hollow nanoparticles (AuNCs and gold nanoshells), which could broaden the application of SPCE in simultaneous sensing and imaging for multianalytes.

In order to provide a theoretical basis for the preparation of electrode and the degradation of salicylic acid Ni - based Ag - Cu alloy electrodes were prepared by electrodeposition method, which was further applied in the degradation process of salicylic acid. The electrochemical properties of the Ni - based Ag - Cu alloy electrodes with different molar ratios of Ag - Cu were studied. Under the same plate spacing, plus voltage, electrolysis time, the effects of electrolyte concentration on the degradation rate of salicylic acid were explored and the electrochemical oxidation degradation and ultrasound - assisted electrochemical synergetic degradation rate were compared. Results showed that under the same temperature, current density, electrode materials and distance between the anode and the cathode, when nAg∶nCu in the electrodeposition solution was equal to 8∶2, the surface morphology of Ni - based Ag - Cu alloy electrode is good, and the degradation rate of salicylic acid was the highest. The most suitable Na2SO4 electrolyte concentration was 1.064 g/L. Under this condition, the degradation rate of salicylic acid was 98.01%, and the ultrasound - assisted electrochemical oxidation rate was 99.89%, indicating that the degradation rate of salicylic acid under the synergy effect was higher.

教育实习是师范生向专业中学教师转变的起点,是培养师范生综合素质的有机组成部分.本文在探讨目前高等师范院校所采用的教育实习成绩评价模式存在的问题的基础上,以促进高校师范类学生的专业发展为出发点,借鉴成熟的绩效管理思想来分析和完善教育实习评价量表,不仅创新了教育实习成绩评价模式,在一定程度上也细化了教育实习成绩评价的内容,对提高教育实习质量、 加强师范生教育教学专业性具有积极的现实意义.

为寻找质优价廉的析氢催化剂,本研究以废旧金属网为单室微生物电解池(MEC)阴极,在不同外加电压下考察其制氢性能.同时利用16S rDNA扩增测序技术分析原接种污泥、MFC和MEC阳极微生物的菌落特点.实验结果表明,随着外加电压的增大,MEC产生的最大电流密度和周期运行时间分别呈现增大和缩短的趋势.外加0.7V电压时,废旧金属网阴极MEC的氢气产率和电能回收率分别达到0.330±0.012 m3H2·m3· d-1和177.0±5.6％,远高于0.5V时的数值,与0.9 V时相差不大.废旧金属网阴极MEC的产氢能力可以和Pt/C阴极MEC相媲美,且具有良好的运行稳定性.16S rDNA扩增测序结果显示培养环境对微生物的富集与淘汰有很大影响.在外加电场环境中MEC阳极的优势菌落地杆菌属(Geobacter)得到很大程度富集,相对丰度高达79.4％以上.

A label-free fluorescent aptasensing platform was fabricated and a simple and rapid method to detect Hg2+ ion in aqueous solution was put forward by means of berberine and Hg2+ ion-aptamer are as the fluorescence probe and the recognition element, respectively. Various factors including the concentration of berberine, Hg2+ ion and Hg2+ ion-aptamer, pH effect and the reaction time were investigated in detail. Under the optimal experimental conditions, in the sensing system, the fluorescence intensity changes displayed a calibration response for Hg2+ ion in the range of 0.1 μM to 10.0 μM and the detection limit was of 7.7 nM (S/N = 3). The fabricated label-free fluorescence aptasensor is not only conveniently but also effectively applicable used for analysis of Hg2+ ion in blood serum and tap water samples and the recovery range is of 96.0%-105.7%. In brief, this study offers an easy, economical and stable assay system for detecting Hg2+ ion in rough condition.

In this study, a “direct-starting” procedure was used to activate a single-chamber biocathode microbial electrolysis cell (MEC) and the development of a biocathode was studied through output current curves and cyclic voltammograms. It only took 163 h for a successful start-up, and a current density of 14.75 A/m2 was obtained. In the formal hydrogen-production stage, it was found that the biocathode MEC was comparable with the Pt/C cathode MEC in terms of current density and energy efficiency, and the hydrogen recovery, cathodic hydrogen recovery, and hydrogen production rate of the biocathode MEC were 71.22% ± 8.98%, 79.42% ± 5.94%, and 0.428 ± 0.054 m3 H2/m3 · days, respectively, which were slightly higher than those obtained with the Pt/C cathode MEC. Besides, under the effect of applied voltage, the microbial populations in the anodophilic biofilm of MEC (MECan) and the cathodophilic biofilm of MEC (MECca) were less diverse than those of the original aerobic activated sludge (AAS) and the anodophilic biofilm of MEC (MECan). Furthermore, the microbial community structures evidently differed between MECan/MECca and AAS/MFC.

采用电沉积法制备了Ti/Ag+Cu电极并将其用于水杨酸的降解.对含有不同n(Ag)∶n(Cu)的Ti/Ag+Cu电极的电化学性能进行了研究,考察了支持电解质Na2SO4的浓度对水杨酸降解率的影响,并对超声波降解、电化学氧化降解和声电协同降解效果进行了比较.结果表明:在室温条件下,支持电解质Na2SO4的浓度为1.441 g·L-1,Ti/Ag+ Cu电极的n(Ag)∶n(Cu) =5∶5时水杨酸的声电协同降解率为99.2％,有很好的协同降解效用.

In this study, we have constructed ZnCr-LDH/g-C3N4 composite photocatalysts via in-situ synthesis approach. This composite material was used as catalyst interlayer of BPM to promote water dissociation. Results indicated that the combination of ZnCr-LDH and g-C3N4 could effectively improve the photoelectrocatalytic water dissociation activity. When the experiment time lasted for 1 h, the pH decreased to 1.52 in compartment 2, and increased to 13.11 in compartment 4 by using ZnCr-LDH/g-C3N4 composite catalyst.

In this study, a novel GQDs/PANI/g-C3N4 ternary heterostructure was successfully designed and prepared by an in-situ polymerization and electrostatic self-assembly approach. The prepared GQDs/PANI/g-C3N4 was used as interlayer of bipolar membrane (BPM) to promote water dissociation. Results revealed that GQDs/PANI/g-C3N4 ternary photocatalyst exhibits excellent photoelectrocatalytic performance for water dissociation in BPM. (C) 2017 Published by Elsevier B.V.

A new view to determine concentration of dissolved acetylene in ambient temperature and pressure was put forward,and solubility of acetylene in different solvents was investigated by UV-Vis.(UV-Vis spectrophotometry).Influence of cosolvents such as acetone,TEG(triethylene glycol),DMSO(dimethyl sulfoxide),DMF(N,N-dimethyl formamide)especially the green cosolvent of TEG and its mechanism and volume fraction,temperature and scan rate on the process of electrochemical oxidation of acetylene at Pt electrode were examined by CV(cyclic voltammetry).The analysis results show that the concentration of dissolved acetylene can be determined accurately through claret-colored copper acetylide by UV-Vis.(at 542 nm),the solubility order of acetylene in different solvents is DMF>DMSO>TEG>acetone,the hydrogen bonding interactions were identified as the main interaction controlling the mutual solubility of the H2O in Na2SO4 solution and TEG in the system,and when the supporting electrolyte is 0.5 mol·L-1 Na2SO4 with TEG(vol.9％),the dissolved acetylene can be the most easily oxidized by OH· from the electrolysis process of Na2SO4 solution and the ipa(anodic peak current)is maximum,the process of electrochemical oxidation of acetylene at Pd electrode is under adsorption control and irreversible,the Ea(apparent activation energy)of the process of electrochemical oxidation of acetylene at Pd electrode is 13.20 kJ·mol-1.This study expects to seek a kind of good solvent acetylene and provides theoretical basis and experimental guidance to the research of electrochemical oxidation acetylene process and the development of sensor for acetylene(especially electrochemical sensor for acetylene),green chemistry and acetylene chemical industry.

A new view to determine concentration of dissolved acetylene in ambient temperature and pressure was put forward, and solubility of acetylene in different solvents was investigated by UV-Vis. (UV-Vis spectrophotometry). Influence of cosolvents such as acetone, TEG (triethylene glycol), DMSO (dimethyl sulfoxide), DMF (N, N-dimethyl formamide) especially the green cosolvent of TEG and its mechanism and volume fraction, temperature and scan rate on the process of electrochemical oxidation of acetylene at Pt electrode were examined by CV (cyclic voltammetry). The analysis results show that the concentration of dissolved acetylene can be determined accurately through claret-colored copper acetylide by UV-Vis. (at 542 nm), the solubility order of acetylene in different solvents is DMF>DMSO>TEG>acetone, the hydrogen bonding interactions were identified as the main interaction controlling the mutual solubility of the H2O in Na2SO4 solution and TEG in the system, and when the supporting electrolyte is 0.5 mol center dot L-1 Na2SO4 with TEG (vol.9%), the dissolved acetylene can be the most easily oxidized by OH center dot from the electrolysis process of Na2SO4 solution and the i(pa) (anodic peak current) is maximum, the process of electrochemical oxidation of acetylene at Pd electrode is under adsorption control and irreversible, the E-a (apparent activation energy) of the process of electrochemical oxidation of acetylene at Pd electrode is 13.20 kJ center dot mot(-1). This study expects to seek a kind of good solvent acetylene and provides theoretical basis and experimental guidance to the research of electrochemical oxidation acetylene process and the development of sensor for acetylene (especially electrochemical sensor for acetylene), green chemistry and acetylene chemical industry.

铁矿石中全铁含量可采用多种方法进行测定,不同的方法存在各自不同的系统误差.对不同方法的原理、操作条件、氧化荆、还原剂等比较并对实验方法和结果进行了显著性检验.实验结果表明,SnCl2-TiCl3-Na2WO3-K2 Cr2O7法准确度高、精密度好、结果稳定,也不会给环境带来负面影响,具有很多其他方法所不可比拟的优越性,可以用来测定铁矿石中全铁的含量,为铁矿石中全铁含量测定方法的选择提供了一定的实验依据和理论指导.

Electrocatalytic synthesis of oxalic acid from acetylene has been achieved at Pt electrode. The electrocatalytically synthesized oxalic acid has been characterized by FTIR (Fourier transform infrared spectroscopy) and UV-Vis (UV-Vis spectrophotometry). Influence of electrode material, Na2SO4 concentration, acetone volume fraction, temperature and scan rate have been investigated by CV (cyclic voltammetry). The analysis results show that oxalic acid has been successfully electrocatalytically synthesized from acetylene at the very stable Pt electrode under ambient temperature and pressure, the supporting electrolyte is Na2SO4 (0.5 M) with acetone (2% by volume), the reaction time is 8 h and the conversion efficiency is larger than 20%. The E-a (apparent activation energy) of electrocatalytic oxidation reaction of acetylene at the Pt electrode is 14.42 kJ.mol(-1), the electrocatalytic oxidation process of acetylene is irreversible and under adsorption control. In addition, the reaction mechanism of the electrocatalytic oxidation process of acetylene to oxalic acid has been envisaged successfully based on the principle of adsorption and desorption at Pt electrode surface. It exhibits the excellent electrocatalytic performance of Pt in the electrocatalytic oxidation process of acetylene and heralds more broad potential application prospect of acetylene in chemical industry field.