一种提高气相色谱仪柱效的方法

国产气相色谱仪气体定体积进样装置一般选择旋转式六通阀,进样口按常规的联接方式,由于死体积较大,使色谱峰产生扩展,影响色谱柱的柱效及混合试样的分离度。Nogare等认为,把色谱柱外的死体积降低到最小值是获得理论柱效的一种重要的因素。所以,

Two New Models for the Permeate Flux of the Outer-helical-flow Microfiltration Module

研究新型外旋流管式微滤膜器渗透通量的变化规律,建立渗透通量的稳态经验模型和动态衰减模型两个新模型.二者各有侧重,前者主要针对稳定过滤状态下的渗透通量,作者将影响渗透通量的因素归纳成膜器进口雷诺数和欧拉数等重要的无因次数群,提出了具体的公式;后者用于描述通量随时间衰减变化的过程,是一个幂函数模型,比原有线性模型更符合实际情况.通过实验对这两个通量模型进行验证,最大偏差分别为13.9%和30%.两个模型均有一定实用价值,前者为膜器放大优化设计奠定基础,后者有助于渗透通量的实时监控操作,两者统一,能进一步改善外旋流管式微滤膜器的实用效果.Variation regularities of the permeate flux in the new outer-helical-flow microfiltration module are tested,and then two new mathematical models which emphasize on different aspects in this equipment are presented.The first model stresses on the permeate flux in the stable stage of the filtration.Here we sum up the influence factors into some important dimensionless parameters like Re_θ and Eu which has been introduced for the first time to characterize the energy loss in this assembly,and consequently we conclude a concrete empirical formula for the permeate flux.The second one accentuates the dynamic attenuation process of the flux along with time,which is a power function equation and conforms to the real varying situation better than the existant linear one does.We also validate these new flux models with the experimental data.The deviations between the results predicted in these two equations and the experimental ones are less than 13.9% and 30%,respectively.In summary,although these two new models for the permeate flux in the outer-helical-flow microfiltration module have different perspective and meaning,they both have notable value in the practical use,for example,the former supplies a basis for the scale-up and the optimal design of the module and the latter is helpful for the real-time monitoring operation to the permeate flux.Therefore,integrate them with purpose and we will further advance the application effect of this novel microfiltration equipment.国家自然科学基金(29976025)资