复卷机伺服张力控制系统设计及优化

本研究通过对复卷机工艺流程进行分析,分别对纸幅张力、速度和纠偏的控制系统进行了设计及优化,采用罗克韦尔PLC作为主控制器,结合伺服驱动器和伺服电机等,实现对纸幅张力的稳定控制。该控制系统在实际生产中取得了良好的控制效果,张力调整时间由之前的10 s缩短到5 s内,并且无超调量。     

避雷器氧化锌电阻片老化特性仿真分析

氧化锌电阻片的均一性差会造成电阻片劣化,劣化后的电阻片使得避雷器的泄漏电流和功率损耗增加,造成避雷器击穿破坏,影响电力系统的安全可靠运行。本研究基于现场调研,以避雷器氧化锌电阻片为研究对象,通过试验与仿真相结合的方式,剖析避雷器氧化锌电阻片的老化特性。开展了氧化锌电阻片的加速老化试验,通过试验获得了电阻片的加速老化特性曲线,该老化特性曲线呈现逐步递减最后趋于稳定的趋势,由此说明该试品的长期稳定性好。本研究结合多物理场耦合仿真,可直观分析试验中电阻片表面温度及电场的分布云图,以及电阻片附近气流变化的流线图,文中仿真分析可对现有老化试验方法研究进行有益补充,该研究结果对氧化锌电阻片老化特性的研究具有一定的参考价值。     

不同时期排泥对培养SBBR生物膜的影响

序批式生物膜反应器（sequencing biofilm batch reactor, SBBR）是应用广泛的污水处理方法。为探究不同时期排泥对SBBR污染物去除效果与微生物群落结构的影响,本研究设置了挂膜初期、中期和后期进行排泥的反应器处理生活污水,同时结合16S rDNA高通量测序技术对微生物群落结构进行分析,并采用机器学习（machine learning, ML）的方法,在传统的微生物优势种分析基础上,对测序数据进行深度挖掘,寻找造成组间差异的关键物种。水质测定结果显示,COD去除效果在不同时期排泥的SBBR间没有明显差异,出水COD均低于30mg/L。挂膜中期排泥的SBBR的NH₃-N去除率先达到稳定且高于前期和后期排泥的系统。高通量测序结果显示,各SBBR中微生物优势种均以降解有机物的物种为主。挂膜中期排泥的SBBR中,ML筛选得到的NH₃-N去除相关物种（Hydrogenophaga、Gemmata和Nitrospira）与差异关键物种丰度更高,微生物群落结构稳定性更强,可从微生物层面解释分析SBBR污染物去除效果的差异。     

Arbuscular mycorrhizal symbiosis facilitates apricot seedling(Prunus sibirica L.) growth and photosynthesis in northwest China

Arbuscular mycorrhizal (AM) fungi can successfully enhance photosynthesis (Pn) and plants growth in agri-cultural or grassland ecosystems.However,how the symbio...     

Ag nanoparticles/PPV composite nanofibers with high and sensitive opto-electronic response

The novel Ag nanoparticles/poly(p-phenylene vinylene) [PPV] composite nanofibers were prepared by electrospinning. The transmission electron microscope image shows that the average diameter of composite fibers is about 500 nm and Ag nanoparticles are uniformly dispersed in the PPV matrix with an average diameter of about 25 nm. The Fourier transform infrared spectra suggest that there could be a coordination effect to a certain extent between the Ag atom and the π system of PPV, which is significantly favorable for the dissociation of photoexcitons and the charge transfer at the interface between the Ag nanoparticle and the PPV. The Au top electrode device of the single Ag/PPV composite nanofiber exhibits high and sensitive opto-electronic responses. Under light illumination of 5.76 mW/cm² and voltage of 20 V, the photocurrent is over three times larger than the dark current under same voltage, which indicates that this kind of composite fiber is an excellent opto-electronic nanomaterial.     

Porphyrin-functionalized gold nanoparticles for selective electrochemical detection of peroxyacetic acid

Two layers of cationic iron(III) meso-tetrakis (N-methylpyridinum-4-yl)porphyrin (FeTMPyP) and anionic gold nanoparticles (GNPs) were alternately assembled on a poly(diallyldimethylammonium chloride)-wrapped carbon nanotube (PDDA-CNT)-modified electrode via electrostatic interactions. The porphyrin-functionalized gold nanoparticles were characterized by scanning electron microscopy and UV–vis absorption spectrometry. The (FeTMPyP–GNP)₂/PDDA-CNT modified electrode showed two stable and well-defined peaks at −0.112 V and −0.154 V, which were attributed to the GNP-accelerated redox process of Fe(III)TMPyP/Fe(II)TMPyP. The modified electrode possessed excellent electrocatalytic behavior for the reduction of peroxyacetic acid (PAA). The resulting biosensor exhibited a fast amperometric response to PAA (∼3 s), with a wide linear range from 2.5 × 10⁻⁶ M to 1.05 × 10⁻³ M and a detection limit of 0.5 μM at a signal-to-noise ratio of 3. More importantly, H₂O₂ did not interfere with the detection. Thus, this biosensor enabled highly sensitive detection of PAA without removing H₂O₂ and showed a promising potential in practical applications.     

UV-Fenton氧化法深度处理紫胶洗色废水

研究采用UV-Fenton联合的方法深度处理紫胶洗色废水,通过单因素实验研究了各因素对紫胶洗色废水污染物降解的影响。基于Box-Behnken复合原理,通过数学回归模型和响应曲面法优化得到UV-Fenton氧化法深度处理紫胶洗色废水的最优条件:初始pH=3.0,H_2O_2投加质量浓度为13.7 g/L,FeSO_4投加质量浓度为0.6 g/L,反应时间为2.0 h。最优条件下的COD去除率达87.37%。     

毛细滴管计滴法测定水中氯离子含量

以自制的液滴体积为0.01-0.02 mL的聚乙烯毛细滴管对水中氯离子含量进行数滴分析,其主要仪器外形小巧、便于携带,滴定快速、准确,试剂消耗量约为常量法的5%,滴定剂用量约为20～100滴,氯离子含量不确定度Urel(C)为3.03%,比常量法略小,相对标准偏差与常量法的相当.该法克服了常量法中滴定管、移液管、铁架台和蝴蝶夹等仪器携带不方便的不足.适用于水中氯离子含量的快速分析.     

3-氨基吡唑-4-甲酰胺半硫酸盐的合成

以原甲酸三乙酯、丙二腈为起始原料,合成乙氧亚甲基丙二腈,将其加入80％水合肼中,加热回流1h,生成3-氨基-4-甲酰胺吡唑,将其与浓硫酸混和,调节pH值,40℃下搅拌0．5h,经过滤,重结晶,得到目标化合物3-氨基吡唑-4-甲酰胺半硫酸盐,总收率63．7％（以丙二腈计）。目标化合物结构经红外光谱、核磁共振分析验证。     

临沂城第二水源输水工程顶管施工工艺对比

文章结合临沂城第二水源项目输水工程一标段实际工程施工中,在不同的工程地质条件下,所采取的顶管施工工艺的选定,并对多种顶管施工工艺的优缺点进行了比较阐述。