Search

As air conditioning system long-time running, microorganism like bacterium and fungus propagates easily in high humidity environment such as filter equipment. After the microorganism entering indoor environment through air conditioning system, the air quality would be affected seriously. Air conditioning system which is regarded as potential microbial pollution source is becoming more attention. The study was about isolation and identification of fungal microorganisms on the filter surface of the central air conditioning system in a gymnasium, and then researching on the colonies and mycelium grown and reproduce regular of fungal microorganisms in different thermal environment using thermal methods, aim to lay groundwork of propagation and diffusion mechanism study of fungal microorganisms in air conditioning system and effective air microbial contamination solve by thermal methods. By physiology biochemistry experiment and molecular biological identification, it was shown that the dominant fungi were Penicillium spp. and Cladosporium spp., colonies were 600 cfu/cm2 and 140 cfu/cm2 respectively.

Lespedeza crytobotrya is a shrub species with properties of substantial biomass and widely distributes in the desert region of China. The cellulose separated from Lespedeza after pre-treatment can be enzymatic hydrolyzed into glucose for ethanol or other chemicals production, which are important renewable fuels or raw material for other material synthesis. Moreover it also can be used for cellulosic material production. So it is necessary to evaluate the cellulose of Lespedeza crytobotrya before its utilization. In this study four cellulosic fractions were isolated by pretreatment with low severity steam and post-treatment with alkaline peroxide. They were comparatively studied by sugar analysis and the average degree of polymerization. After alkaline peroxide post-treatment, the hemicelluloses in the cellulosic fractions were removed markedly. The treatment intensity had a profound effect on the average degree of polymerization, which was increased firstly and then decreased. A combination of low severity steam pretreatment and alkaline peroxide post-treatment is an effective method for Lespedeza stalks to obtain high glucose yield.

The performance of excitation control system directly influences the motor’s movement characteristics. Currently, a lot of traditional excitation systems which use analog control circuits have the problem with their poor stability, aging components, slow response and great power lose. Aim to solve these problems, this text designs and implements a digital excitation regulation system based on DSP for DC motor. The regulation system takes full advantage of the powerful data processing ability of DSP chip for real-time rotational speed control of DC motor. This design is capable of ensuring the stability of the excitation system and improving the control efficiency, the circuit design is greatly simplified at the same time.