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orangegirl金虫 (初入文坛)
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PSD curves were obtained by Barrett–Joyner–Halenda (BJH) method and the position of the maximum of the PSD was used as the average pore diameter. The point-of-zero-charge (PZC) measurements were carried out for both MC and MC treated with 2 M HNO3 with pH adjusted de-ionized water. The pH was adjusted using different normality values of HCl and NaOH. The PZC was measured using a pH meter (Elico-127L) adopting the procedure described elsewhere. Before measuring PZC, both the modified and pristine MCs were washed copiously with hot de-ionized water followed by drying in an air oven at 80℃. The pH of adjusted de-ionized water was taken as the initial pH. Finally, the calculated amounts of MC and MC treated with 2 M HNO3 were separately added to sample bottles containing de-ionized water at different pH values followed by sonication for 1 h. The pH was measured and recorded as the final pH. Air permeability of GDLs comprising Vulcan XC-72R, MC and MC treated with 2 M HNO3 were also measured with Automated Capillary Flow Porometer: CFP-1500-AEXBB, Porous Materials, Inc., US. The working diameter (1 cm) and the thickness (0.4 mm) were kept identical for all samples. The tests were performed with differential air-pressure applied to the samples and the corresponding air flow rates through the porous GDLs were recorded. 请帮忙翻译一下，再给我详细介绍一下 PSD curves ， PZC法和里面的 2 M HNO3的M是指什么啊？ [ Last edited by orangegirl on 2009-3-20 at 09:14 ] |
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2楼2009-03-20 10:47:01
3楼2009-03-20 15:11:02
4楼2009-03-20 16:36:34
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orangegirl(金币+5,VIP+0):谢谢 3-21 10:58
orangegirl(金币+5,VIP+0):谢谢 3-21 10:58
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power spectral density(PSD)功率谱密度曲线 功率谱密度谱是一种概率统计方法，是对随机变量均方值的量度。一般用于随机振动分析，连续瞬态响应只能通过概率分布函数进行描述，即出现某水平响应所对应的概率。功率谱密度是结构在随机动态载荷激励下响应的统计结果，是一条功率谱密度值—频率值的关系曲线，其中功率谱密度可以是位移功率谱密度、速度功率谱密度、加速度功率谱密度、力功率谱密度等形式。数学上，功率谱密度值—频率值的关系曲线下的面积就是方差，即响应标准偏差的平方值。 M是指摩尔浓度 |
5楼2009-03-20 16:43:30
naien7
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6楼2009-05-08 09:17:01