中文摘要：

研究表明，生物量浓度的变化会引起溶液的折射率变化，从而导致反射光能量的变化。从菲涅耳公式和折射定律可知，入射角与折射角的数值决定了反射率的大小，反射光能量与界面两边的介质的折射率有关，该文正是从这一物理现象和理论出发，将反射能量的大小与具有实用意义的生物量浓度测量联系起来，建立了一种新的生物量浓度测量方法。文章论述了传感器的组成电路、设计原理、入射角的选择方法。并通过实验研究深入地讨论了在入射角小于和大于临界角两种情况下，对生物量浓度测量的影响、实验结果及理论分析表明：这种方法用于测量微生物液体浓度是可行的，具有生物量浓度在线测量准确、灵敏高、使用寿命长等优点。

英文摘要：

Aimed at detecting the biomass concentration in process of biochemical reaction on-line, the research, from physical phenomena of light reflecting, finds that the energy of refleeting light, on interface of two kinds of mediums, is related with several factors. On basis of refraction law, we also find that the energy of reflecting light is related with refractive index of mediums at both sides of interface. So, in this paper, based on above ideas, authors establish some relations between the energy of reflecting light and the density of liquid, and get a kind of novel detecting method for liquid density by photoelectric sensor. We also discuss several influences from some specialities, such lhat an angle of incidence is less or more than the critical angle, then improve experimental device and method to avoid above influences. The experimental results and theoretical analysis show that this kind of method is effective in detecting the biomass concentration on line, and has some advantages such as high in precision, good in sensitivity, long in life.