化学试剂及仪器购买指南

2009年10月15日

国内正规渠道可购买国外化学试剂:

Sigma-Aldrich:http://www.sigmaaldrich.com/china-mainland.html

Alfa Aesar:http://www.alfa.com/china/

TCI:http://www.tcishanghai.com.cn/

Acros Organics:http://www.acros.com/ 阅读这个条目剩下部分 »

化学试剂纯度

2009年10月15日

我国的试剂规格基本上按纯度(杂质含量的多少)划分,共有高纯、光谱纯、基准、分光纯、优级纯、分析和化学纯等7种。

国家和主管部门颁布质量指标的主要优级纯、分级纯和化学纯3种。

  1. 优级纯(GR:Guaranteed reagent),又称一级品或保证试剂,99.8%,这种试剂纯度最高,杂质含量最低,适合于重要精密的分析工作和科学研究工作,使用绿色瓶签。 阅读这个条目剩下部分 »

各种紫外光的定义及分类

2009年10月12日

ISO 21348 中按波长对各种紫外线进行的定义:

Ultraviolet (UV) irradiances are defined as the wavelength range of (100 u λ < 400) nm.

Ultraviolet C (UVC) irradiances are defined as the wavelength range of (100 =/< λ < 280) nm.

Ultraviolet B (UVB) irradiances are defined as the wavelength range of (280 u λ < 315) nm.

Ultraviolet A (UVA) irradiances are defined as the wavelength range of (315 u λ < 400) nm.

Vacuum Ultraviolet (VUV) irradiances are defined as the wavelength range of (10 =/< λ < 200) nm.

Extreme Ultraviolet (EUV) irradiances are defined as the wavelength range of (10 =/< λ < 121) nm.

Lyman-alpha (Lyman-α) irradiances are defined as the wavelength range of (121 =/< λ < 122) nm.

Far Ultraviolet (FUV) irradiances are defined as the wavelength range of (122 =/< λ < 200) nm.

Middle Ultraviolet (MUV) irradiances are defined as the wavelength range of (200 u λ < 300) nm.

Near Ultraviolet (NUV) irradiances are defined as the wavelength range of (300 u λ < 400) nm.