火焰原子吸收光谱法测定不同生长年限党参不同部位的锌

火焰原子吸收光谱法测定了不同生长年限采收的药用植物党参的地上部分和地下部分中Zn的含量。随着生长年限的增长,Zn的含量在党参的地上部分和地下部分均有减少的趋势;地上部分Zn的含量明显高于地下部分。方法平均加标回收率为101.1%,相对标准偏差(RSD)小于2.0%。测定结果为研究元素锌在不同采收年限党参中的分布及含量与党参的药效关系提供了有用的数据。     

Pressue Dependence of the Ferroelectric-Paraelectric Transition Temperature in KNBO 3 . Comparision with the Ice VII-VIII Transition

New results on the phase diagram of KNbO 3 determined, from 10 to 650 K up to 30 GPa, with Raman scattering are given. On increasing pressure the Curie temperature T c was found to shift down regularly from 700 K, at atmospheric pressure, to 20 K at ～25 GPa. Up to 20 GPa, the pressure dependence of T c follows a classical regime described by the Ising model where the dipolar interaction follow a i 2 /v law, where i is the off-center displacement and v the unit cell volume. This behaviour found also for the ice VII-VIII is very likely encountered in a number of (anti)ferroelectric-paraelectric transformations involving positional disorder.     

多台设备老炼试验数据情形下的可靠性评估

从统计计算的角度出发,提出多台设备老炼试验可靠性评估方法,并模拟计算了可靠度置信下限的覆盖率、分位点及标准差.结果表明此方法具有可行性和实用性.     

激光水下通讯原理探究及部分实验

目前，潜艇通讯方式有以下几类：VHF无线电通讯、ELF无线电通讯、HF／UHF／、VHF无线电通讯、UHF/SHF／EHF卫星通信以及蓝绿激光通讯等。这些通讯方式各有优缺点。这里将对学生开设简单的物理实验，以此来模拟激光在水下通讯，并说明激光水下通讯方案的可行性及优点。     

Determination of the Real Surface Area of Palladium Electrode

Four methods, including voltammetric measurement of double layer capacitance, surface oxides reduction, under potential deposition of Cu and carbon monoxide (CO) stripping have been applied to evaluate the real surface area of a polycrystalline Pd (pc-Pd) electrode. The results reveal that the second and third methods lead to consistent results with deviations below 5%. And from the determined double layer capacitance and CO stripping charge, it is deduced that the double layer capacity unit area is 23.1±0.4 μF/cm² and the saturated CO adlayer should be ca. 0.66 ML in order to ensure that the real surface area as determined isconsistent with the other two techniques. The applicability as well as the attentions when applying these techniques for the determination of the real surface area of pc-Pd electrodes have been discussed.     

钯电极活性表面积的计算

通过测量双电层电容、氧化物还原、欠电位沉积铜和一氧化碳脱附的电量四种方法估算了多晶钯电极的活性表面积. 结果表明,使用第二和第三种方法计算得到的钯电极活性表面积有较好的一致性,误差小于5%,为了使另外两种方法计算得到的面积与之相近,推断单位面积双电层电容双电层电容23.1±0.4 μF/cm² ,饱和吸附一氧化碳的覆盖度大约为0.66 ML,讨论了使用这些方法在确定多晶钯电极活性面积时的关键步骤及适用性.     

"自动回流消化仪"消化-AFS法测定油中的砷

本文报道了“自动回流消化仪”消化，原子荧光光度法测定的油中的砷。“自动回流消化仪”消化油既防止了砷元素的损失，又能使油容易消化，同时在试剂用量、劳动强度、消化速度等方面都有较好的效果。原子荧光光度法，采用新的仪器和原理，提出了方法的灵敏度。该法回收率为91.8％－104.7%,相对标准偏差0.51%，与传统湿法消化法比较无显著性差异（t0.05）。