A K+-selective electrode and a Na+-selective electrode were used to construct a measuring cell without liquid-junction for the determination of the ion activity ratio of K+ to Na+ in soil suspensions. The measured cel...A K+-selective electrode and a Na+-selective electrode were used to construct a measuring cell without liquid-junction for the determination of the ion activity ratio of K+ to Na+ in soil suspensions. The measured cell potential was not affected by the total electrolyte concentration when the total cation concentration was 10-1-10-3 mol L-1 and the concentration ratio CK+ / CNa+. was 10:1 to 1:50. When the concentration ratios were equal to 1and the total electrolyte concentrations were 10-2 and 10-3 mol L-1, the ion activity ratio measurement would not be affected by pH in the pH range of 3.5 to 11.5 and 4.4 to 11 respectively. Ions other than H+ have no remarkable influence on the measurement. The ion activity ratio of K+ to Na+ measured directly in soil suspension agree well with those in centrifuged supernant solution. The relative deviation was within 4%. From the measured ion activity ratio, the difference of the bonding energies of K+ and Na+ ions was calculated.展开更多
CVD polycrystalline diamond surfaces were etched using reactive ion etching system with either a conventional stainless steel electrode or MgO sintered ceramic containing electrode. The micro-needle array of high aspe...CVD polycrystalline diamond surfaces were etched using reactive ion etching system with either a conventional stainless steel electrode or MgO sintered ceramic containing electrode. The micro-needle array of high aspect on diamond substrate surfaces obtained with MgO electrode was fabricated by using back-sputtering from MgO electrode. The RMS roughness of diamond substrate surfaces obtained with MgO electrode is higher than those obtained with stainless steel electrode. The secondary electron emission coefficient in Ne gas of the diamond obtained with MgO electrode was twice that obtained with the stainless steel electrode.展开更多
因具有大量的晶界和离子扩散通道,低结晶度的电极活性材料有望在储能领域中实现更好的性能.然而在大多数应用中通常是结晶良好的样品具有更好的稳定性,稳定性较差限制了低结晶样品在相关研究领域的应用.本文利用一种溶剂热法调控N-甲基...因具有大量的晶界和离子扩散通道,低结晶度的电极活性材料有望在储能领域中实现更好的性能.然而在大多数应用中通常是结晶良好的样品具有更好的稳定性,稳定性较差限制了低结晶样品在相关研究领域的应用.本文利用一种溶剂热法调控N-甲基吡咯烷酮和水混合溶剂的体积比以合成低结晶度的镍钴氢氧化物(NiCo-OH-L).研究发现,将合成的镍钴氢氧化物用作镍-锌电池正极时,NiCo-OH-L不仅表现出与高结晶度的同类样品相当的循环稳定性能,而且在1-50 A g^(-1)的电流范围内显示出更高的容量以及容量保持率.其优异的电化学性能可归因于低结晶的结构,显著提高的比表面积和降低的电荷转移电阻.此外,NiCo-OH-L的钴组分进一步提高了倍率和循环稳定性能.NiCo-OH-L在1 A g^(-1)时的比容量达到238.9 mA h g^(-1),当电流密度升至50 A g^(-1)时的容量仍有116.4 mA h g^(-1),显示出高容量和高倍率性能.不仅如此,由NiCo-OH-L组装成的镍-锌电池在不同的电流和循环周期下也表现出较高的性能.展开更多
文摘A K+-selective electrode and a Na+-selective electrode were used to construct a measuring cell without liquid-junction for the determination of the ion activity ratio of K+ to Na+ in soil suspensions. The measured cell potential was not affected by the total electrolyte concentration when the total cation concentration was 10-1-10-3 mol L-1 and the concentration ratio CK+ / CNa+. was 10:1 to 1:50. When the concentration ratios were equal to 1and the total electrolyte concentrations were 10-2 and 10-3 mol L-1, the ion activity ratio measurement would not be affected by pH in the pH range of 3.5 to 11.5 and 4.4 to 11 respectively. Ions other than H+ have no remarkable influence on the measurement. The ion activity ratio of K+ to Na+ measured directly in soil suspension agree well with those in centrifuged supernant solution. The relative deviation was within 4%. From the measured ion activity ratio, the difference of the bonding energies of K+ and Na+ ions was calculated.
文摘CVD polycrystalline diamond surfaces were etched using reactive ion etching system with either a conventional stainless steel electrode or MgO sintered ceramic containing electrode. The micro-needle array of high aspect on diamond substrate surfaces obtained with MgO electrode was fabricated by using back-sputtering from MgO electrode. The RMS roughness of diamond substrate surfaces obtained with MgO electrode is higher than those obtained with stainless steel electrode. The secondary electron emission coefficient in Ne gas of the diamond obtained with MgO electrode was twice that obtained with the stainless steel electrode.
基金financially supported by the National Natural Science Foundation of China(21905148)。
文摘因具有大量的晶界和离子扩散通道,低结晶度的电极活性材料有望在储能领域中实现更好的性能.然而在大多数应用中通常是结晶良好的样品具有更好的稳定性,稳定性较差限制了低结晶样品在相关研究领域的应用.本文利用一种溶剂热法调控N-甲基吡咯烷酮和水混合溶剂的体积比以合成低结晶度的镍钴氢氧化物(NiCo-OH-L).研究发现,将合成的镍钴氢氧化物用作镍-锌电池正极时,NiCo-OH-L不仅表现出与高结晶度的同类样品相当的循环稳定性能,而且在1-50 A g^(-1)的电流范围内显示出更高的容量以及容量保持率.其优异的电化学性能可归因于低结晶的结构,显著提高的比表面积和降低的电荷转移电阻.此外,NiCo-OH-L的钴组分进一步提高了倍率和循环稳定性能.NiCo-OH-L在1 A g^(-1)时的比容量达到238.9 mA h g^(-1),当电流密度升至50 A g^(-1)时的容量仍有116.4 mA h g^(-1),显示出高容量和高倍率性能.不仅如此,由NiCo-OH-L组装成的镍-锌电池在不同的电流和循环周期下也表现出较高的性能.
