Design and optimization of the magnetic adsorption mechanism of a pipeline-climbing robot

Journal of Mechanical Science and Technology - This study has designed a type of pipeline-climbing robot to solve the problem in which the corrosion of offshore oil pipelines and the adhesion of...     

Growth inhibition of Fusarium graminearum and deoxynivalenol detoxification by lactic acid bacteria and their application in sourdough bread

Eight lactic acid bacteria (LAB) strains were screened for their ability to inhibit Fusarium graminearum (F. graminearum) growth and remove deoxynivalenol (DON). Furthermore, the selected LAB strains were applied as starter cultures to evaluate their performance during the breadmaking process. Lactobacillus plantarum (L. plantarum) AR524 exhibited strong inhibitory activity against F. graminearum growth in a pH-dependent manner and removed up to 40.9% of DON, mainly through cell wall binding. Compared with the control, L. plantarum AR524 inhibited 60.19% of F. graminearum growth and removed 50.53% of DON during breadmaking. The texture properties of the bread were also remarkably improved by L. plantarum AR524, and its shelf life was extended from 3 days to 6 days without the application of any chemical preservatives. Therefore, L. plantarum AR524 shows excellent potential for application as a bioprotective starter culture in bakery products.     

Luminescence properties and energy transfer of co-doped Ba<Subscript>3</Subscript>GdNa(PO<Subscript>4</Subscript>)<Subscript>3</Subscript>F:Ce<Superscript>3+</Superscript>,Tb<Superscript>3+</Superscript> green-emitting phosphors

Phase pure Ce³⁺ and Tb³⁺ singly doped and Ce³⁺/Tb³⁺ co-doped Ba₃GdNa(PO₄)₃F samples have been synthesized via the high temperature solid-state reaction. The crystal structures, photoluminescence properties, fluorescence lifetimes, thermal properties and energy transfer of Ba₃GdNa(PO₄)₃F:Ce³⁺,Tb³⁺ were systematically investigated. Rietveld structure refinement indicates that Ba₃GdNa(PO₄)₃F crystallizes in a hexagonal crystal system with the space group P-6. For the co-doped Ba₃GdNa(PO₄)₃F:Ce³⁺,Tb³⁺ samples, the emission color can be tuned from blue to green by varying the doping concentration of the Tb³⁺ ions. The intense green emission was realized in the Ba₃GdNa(PO₄)₃F:Ce³⁺,Tb³⁺ phosphors on the basis of the highly efficient energy transfer from Ce³⁺ to Tb³⁺. Also the energy transfer mechanism has been confirmed to be quadrupole–quadrupole interaction, which can be validated via the agreement of critical distances obtained from the concentration quenching (13.84 Å). These results show that the developed phosphors may possess potential applications in near-ultraviolet pumped white light-emitting diodes.     

正火型V-N-Ti和Nb-V-Ti海工钢焊接粗晶热影响组织和韧性研究

用焊接热模拟方法研究了V-N-Ti和Nb-V-Ti微合金化正火型海工钢模拟粗晶热影响区(CGHAZ)组织和韧性的变化规律。结果表明,组织的不同使V-N-Ti设计正火型海工钢的模拟CGHAZ韧性比Nb-V-Ti钢的好。对于V-N-Ti钢,较高的N含量提高了富Ti(Ti, V)(C, N)粒子析出温度和铁素体形核能力,使模拟CGHAZ原始奥氏体晶粒和(取向差角为15°)晶粒细化,并生成能阻止或使解理裂纹的偏转细小多边形铁素体,因此具有良好的低温韧性。而Nb-V-Ti钢模拟CGHAZ原奥氏体晶界上的链状M-A、粗大的原始奥氏体晶粒和有效晶粒尺寸,是模拟CGHAZ韧性差的原因。     

Emission Wavelength Tuning via Competing Lattice Expansion and Octahedral Tilting for Efficient Red Perovskite Light-Emitting Diodes

The band-edge electronic structure of lead halide perovskites (ABX₃) is composed of the orbitals of B and X components and can be tuned through the composition and structure of the BX₆ octahedron. Although A-site cations do not directly contribute to near-edge states, the bandgap of 3D metal halide perovskites can be affected by A-cations through BX₆ octahedron tilting or lattice size variation. Here, as confirmed by the Rietveld refinement results of X-ray diffraction characterization, the competition between lattice expansion and octahedral tilting is identified for the first time in emission wavelength tuning when introducing a large A-site cation (C₂H₅NH₃⁺, EA⁺) into 1-naphthylmethylammonium iodide-passivated CsPbI₃ system. The former dominates spectral redshift, while the latter leads to a blueshift of emission peak, which broadens the way to tune the emission wavelength. In addition, excess cations can also passivate the perovskites, leading to a photoluminescence (PL) quantum yield as high as 61%, increased average PL lifetime of 74.7 ns, and a high radiative and non-radiative recombination ratio of 15.7. Eventually, spectral-stable deep-red perovskite light-emitting diode with a maximum external quantum efficiency of 17.5% is realized, which is one of the highest efficiencies without using any light outcoupling and anti-solvent techniques.     

Shade darkening effect of polyorganosiloxane modified with amino and hydroxy groups on dyed polyester microfiber fabric

The novel polyorganosiloxane material S‐101 modified with amino and hydroxy groups is synthesized. Shade darkening effect of modified polyorganosiloxane on dyed polyester microfiber fabric is investigated by reflectance spectrum, color yield (K/S), and the color differences (ΔE). The colorimetric data of CIELAB is discussed. The results show that the novel material of silicone polymer modified with amino and hydroxy groups has excellent shade darkening effect on dyed polyester microfiber fabric. The rates of the color yield increase (I%) of all dyed fabric with four dyes (Disperse Yellow S‐4RL, Red GS, Blue 2BLN, and Black SF‐R) exceed 10%. The shapes of the reflectance spectra curves of the dyed fabrics before and after treated with S‐101 are not noticeable change. The dyed fabrics with the polymer have not significant effect on the wash fastness and wet rubbing fastness. The low reflectance thin film on dyed fabrics is formed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Glare 层板试样制备对其性能的影响研究

介绍了Glare层板的试样制备对其性能的影响。Glare层板试样制备主要包括试样设计与加工、加强片粘接以及裂纹预制等工艺,不合理的试样设计、加强片粘接缺陷以及测试工作区的加工误差都会对测试产生重要影响。     

利用氧化还原反应储能的储能介质研究进展

受天气和环境变化的影响,太阳能热发电系统存在间歇性供应的问题,热化学储能的提出为该问题的解决提供了办法。本文对金属氧化物及钙钛矿作为储能介质的热化学反应特性以及反应物结构对反应产生的影响等方面的研究现状进行了阐述。结果显示,金属氧化物及钙钛矿的氧化还原循环反应储能,具有反应温度与太阳能热发电相适应且能量密度大、储能稳定、能量损失小等一系列优势,应用前景广泛。与此同时,基于该项技术还不成熟,在实际应用转化的过程中存在技术经济问题,指出未来主要的研究方向是反应物氧化还原反应循环性能研究、储/放热过程的模拟、储能系统的设计及实施一定规模的试验等。     

便携式设备无线充电技术发展及关键技术

随着无线电能传输技术的不断发展,其在便携式设备中展现出良好的应用前景。相比传统的有线充电,便携式设备无线充电的方式具有灵活、便捷、高通用性等优点,但在实际应用中又存在其特殊性。为此,该文对便携式设备无线充电技术的发展现状进行了梳理,首先介绍了现有的便携式设备无线充电产品的主流标准;然后给出了系统的基本结构,并归纳了其特点;接着根据上述特点从平面线圈设计、空间无线电能传输、异物检测、多负载、电磁问题等方面论述了便携式设备无线充电关键技术的研究现状;最后展望了便携式设备无线充电技术今后进一步的发展方向。     

PC和PET油中热老化分解物特性分析

油纸绝缘系统的性能直接影响变压器的可靠性和使用寿命。绝缘纸介电常数大、耐高温性较差和易分解的缺陷,限制了油浸式变压器朝大容量、小体积方向的发展。选择聚碳酸酯(PC)和聚酯薄膜(PET)两种聚合物材料与绝缘纸作对比,分别在90℃、110℃和130℃三种温度下进行为期300 d的老化试验,并对油中生成物、酸值、油中溶解气体和机械性能进行测试,结合其聚合度和微观表面形貌变化,分析3种材料油中老化特性变化规律,并寻找判断其老化程度的特征量。