Influence of the Particle Size of CaCO3 on the Adhesion of Filled EVA Materials

A surface treatment with corona discharge was used to improve the adhesion properties of ethylene vinyl acetate copolymer (EVA) containing small amounts of four CaCO₃ with different particle size. The nature of the surface modifications produced by the corona discharge treatment and the adhesion to a polychloroprene adhesive were assessed. Treatment of CaCO₃ filled EVA with corona discharge produced a decrease in water contact angle value, irrelevant to the different particle size of the calcium carbonates. The corona discharge treatment created C-O and C=O moieties on the EVA surface and also increased the peel strength, more markedly as the CaCO₃ particle size increased. In general, a mixed (adhesion + cohesive in the EVA) failure in the filled EVA material was produced (assessed by IR-ATR spectroscopy and SEM micrographs of the failed surfaces), but the failure was more cohesive in the EVA containing higher particle size CaCO₃. The durability of the joints was also studied.     

电沉积工艺对Mg-Ni储氢合金的电化学性能的影响

用电沉积的方法制备了镁 镍储氢合金,探讨了电沉积条件对合金的电化学性能的影响.XRD显示沉积层中含有非晶态Mg Ni相和微晶态Mg相.AAS分析表明沉积合金中Mg的摩尔分数达 8. 57%.合金的放电容量最高为 75. 547mA·h·g-1.     

溶剂热法控制合成规则的LiFePO4颗粒

采用溶剂热法在H2O和异丙醇的混合溶剂中合成橄榄石结构的磷酸铁锂(LiFePO4). 场发射扫描电镜(FESEM)结果表明, LiFePO4产品的形貌与导电添加剂密切相关, 当改变导电添加剂的种类(蔗糖、碳黑和石墨)时, 分别得到了棒状和方块状的LiFePO4颗粒. TEM和选区电子衍射(SAED)的结果表明, 棒状的LiFePO4晶体沿着[201]方向取向生长. 取向机理可能在于添加剂对晶体生长的吸附阻止作用. 充放电测试表明, 溶剂热法合成的LiFePO4(添加蔗糖)具有145.2 mAh·g-1的可逆容量和良好的循环保持能力, 且表现出优良的倍率放电性能和高温特性, 其4C放电容量为98.1 mAh·g-1, 保持了0.1C容量的67.6%, 且放电电压平台仍保持在3.12 V(vs Li/Li+).     

β-NiOOH的制备及充放电性能

电池正负极材料有充放电态之分 ,如 Mn O2 、Zn处于充电态 ,Ni(OH) 2 、MH、Li Co O2 、L i Ni O2等处于放电态 ,将起始荷电态不同的电极组装成电池 ,必然存在充放电态不匹配的问题 ,给电池化成带来困难 [1,2 ] .如 Zn/Ni电池正极改用充电态Ni OOH为原材料 ,则负极就可用充电态 Zn为原材料 ,很显然 Zn作为负极材料优于 Zn O,这就引发了将 Ni(OH) 2 氧化为 Ni OOH的研究 .本文采用改进的化学氧化法由β- Ni(OH ) 2 制备β-Ni OOH粉体 [3,4 ] ,对纯样及其与 Mn O2 混合的掺杂样的充放循环性能和反应机理进行了研究 .所用试剂…     

Nitrogen effects in multi-matrix calibrations by radiofrequency glow discharge – optical emission spectrometry

A study about the effect of nitrogen in the calibration curves of a series of analytical emission lines has been carried out in this work. Fifteen reference materials with different matrices (Fe, Al, Zn, Cu and Ni) were used (three of these reference materials contain nitrogen in their composition) and plots of intensity versus the product “sputtering rate times element concentration” were constructed for emission lines of the analytes considered in this work (Al, Fe, Cu, Cr, C, Mo, Zn, Si, Ti and Ni). Two different fits were performed in each plot, first considering only the points corresponding to samples without nitrogen in their composition and secondly including all the points. The results show almost negligible differences in the emission yields calculated. On the other hand, a mixture of Ar containing 0.5% N₂ was employed to check if the nitrogen effect was present at higher concentrations than those expected in analysis when samples with high nitrogen concentrations are used. Differences between the slopes of the calibration curves with the Ar/N₂ and pure Ar discharges were obtained (up to 30%). A study of the molecular bands recorded in the spectra when nitrogen is present in the discharge and determination of the resulting interferences on the analytes have been performed. Figure Glow discharge powered with radiofrequency energy     

Nitrogen incorporation in saturated aliphatic C6–C8 hydrocarbons and ethanol in low‐pressure nitrogen plasma generated by a hollow cathode discharge ion source

Ion/molecule reactions of saturated hydrocarbons (n‐hexane, cyclohexane, n‐heptane, n‐octane and isooctane) in 28‐Torr N₂ plasma generated by a hollow cathode discharge ion source were investigated using an Orbitrap mass spectrometer. It was found that the ions with [M+14]⁺ were observed as the major ions (M: sample molecule). The exact mass analysis revealed that the ions are nitrogenated molecules, [M+N]⁺ formed by the reactions of N₃⁺ with M. The reaction, N₃⁺ + M → [M+N]⁺ + N₂, were examined by the density functional theory calculations. It was found that N₃⁺ abstracts the H atom from hydrocarbon molecules leading to the formation of protonated imines in the forms of R′R″C?NH₂⁺ (i.e. C–H bond nitrogenation). This result is in accord with the fact that elimination of NH₃ is the major channel for MS/MS of [M+N]⁺. That is, nitrogen is incorporated in the C–H bonds of saturated hydrocarbons. No nitrogenation was observed for benzene and acetone, which was ascribed to the formation of stable charge‐transfer complexes benzene????N₃⁺ and acetone????N₃⁺ revealed by density functional theory calculations. Copyright © 2016 John Wiley & Sons, Ltd.     

Direct detection of explosives on solid surfaces by mass spectrometry with an ambient ion source based on dielectric barrier discharge

Trace amounts of explosives on solid surfaces were detected by mass spectrometry at ambient conditions with a new technique termed dielectric barrier discharge ionization (DBDI). By the needle-plate discharge mode, a plasma discharge with energetic electrons was generated, which could launch the desorption and ionization of the explosives from solid surfaces. Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), 2,4,6-trinitrotoluene (TNT), and pentaerythritol tetranitrate (PETN) were desorbed directly from the explosives-contaminated surface by DBDI, forming the typical anions of [TNT](-), [TNT - H](-), [RDX + NO(2)](-), [PETN + ONO(2)](-), and [RDX + ONO(2)](-). The ions were transferred into the MS instrument for analysis in the negative ion mode. The detection limit of present method was 10 pg for TNT (m/z 197, S/N 8 : 1), 0.1 ng for RDX (m/z 284, S/N 10 : 1), and 1 ng for PETN (m/z 260, S/N 12 : 1). The present method allowed the detection of trace explosives on various matrices, including paper, cloth, chemical fiber, glass, paints, and soil. A relative standard deviation of 5.57% was achieved by depositing 100 pg of TNT on these matrices. The analysis of A-5, a mixture of RDX and additives, has been carried out and the results were consistent with the reference values. The DBDI-MS method represents a simple and rapid way for the detection of explosives with high sensitivity and specificity, which is especially useful when they are present in trace amounts on ordinary environmental surfaces.     

Synthesis and charge/discharge properties of polyacetylenes carrying 2,2,6,6-tetramethyl-1-piperidinoxy radicals

The 2,2,6,6-tetramethyl-1-piperidinoxy (TEMPO)-containing acetylenic monomers HC[triple bond]CC(6)H(3)-p,m-(CONH-4-TEMPO)(2) (1), HC[triple bond]CC(6)H(3)-p,m-(COO-4-TEMPO)(2) (2), (S,S,S,S)-HC[triple bond]CC(6)H(3)-p,m-[CO-NHCH{COO-(4-TEMPO)}CH(2)COO-(4-TEMPO)](2) (3), (S,S)-HC[triple bond]CC(6)H(4)CO-NHCH{COO-(4-TEMPO)}CH(2)COO-(4-TEMPO) (4), HC[triple bond]CC(6)H(4)-p-OCO-4-TEMPO (5), HC[triple bond]CCH(2)C(CH(3))(CH(2)OCO-4-TEMPO)(2) (6), HC[triple bond]CCH(2)NHCO-4-TEMPO (7), and HC[triple bond]CCH(2)OCO-4-TEMPO (8) were polymerized to afford novel polymers containing the TEMPO radical at high densities. Monomers 1, 3-6, and 8 provided polymers with average molecular weights of 10 000-136 500 in 62-99 % yield in the presence of a rhodium catalyst, whereas monomers 2 and 7 gave insoluble polymers in 100 % yield. The formed polymers were thermally stable up to approximately 274 degrees C according to thermogravimetric analysis (TGA). All the TEMPO-containing polymers demonstrated reversible charge/discharge processes, whose discharge capacities were 21.3-108 A h kg(-1). In particular, the capacity of poly(1)-, poly(4)-, and poly(5)-based cells reached 108, 96.3, and 89.3 A h kg(-1), respectively, which practically coincided with their theoretical values.     

Electrical Features of Radio-frequency,Atmospheric-pressure,Bare-metallic-electrode Glow Discharges

Radio-frequency (RF), atmospheric-pressure glow discharge (APGD) plasmas with bare metallic electrodes have promising prospects in the fields of plasma-aided etching, deposition, disinfection and sterilization, etc. In this paper, an induced gas discharge approach is proposed for obtaining the RF, atmospheric-pressure, γ-mode, glow discharges with pure nitrogen or air as the primary plasma-working gas using bare metallic electrodes. The discharge characteristics, including the discharge mode, the breakdown voltage and discharge voltage for sustaining α mode and/or γ mode discharges, of the RF APGD plasmas of helium, argon, nitrogen, air or their mixtures using a planar-type plasma generator are presented in this study. The uniformity (no filaments) of the discharges is confirmed by the images taken by an iCCD with a short exposure time (10 ns). The effects of different gap spacings and electrode materials on the discharge characteristics, the variations of the sheath thickness and the electron number density are also studied in this paper.     

Au nanolayers deposited on polyethyleneterephtalate and polytetrafluorethylene degraded by plasma discharge

Polyethyleneterephtalate (PET) and polytetrafluorethylene (PTFE) foils were modified by plasma discharge. The effect of plasma modification on polymer surface wettability and on properties of gold coatings were studied as a function of time from plasma exposure (aging time) and polymer substrate temperature. Thickness, sheet resistance, and surface topology of gold layers were studied. Aging of the plasma‐exposed samples is accompanied by increase in contact angle, which is explained by rearrangement of the polymer segments in the polymer surface monolayer, and a decrease in the concentration of polar groups. The aging also leads to a decline in surface roughness R_a measured by atomic force microscopy (AFM). Under deposition conditions, comparable thicknesses of deposited Au layers were prepared on pristine PET and plasma‐treated PET and PTFE samples. The thinnest Au layers were evaporated onto pristine PTFE. The sheet resistance decreases with increasing thickness of Au layer. Plasma treatment leads to an increase of PTFE surface roughness, which becomes even more pronounced after Au deposition. A higher roughness shows that the PET samples are deposited with the Au layer at temperatures above the glassy transition temperature T_g. Copyright © 2006 John Wiley & Sons, Ltd.