ABSTRACT
The mechanical structure topology design based on substructure always adopts the traditional substructure design method, which often comes from the experience and is limited by the inherent or stereotyped design thinking. A substructure design method based on biological unit cell (UC) is proposed, which draws inspiration from the biological efficient load-bearing topology structure. Especially, the thought of the formalized problem-solving of extension matter-element is introduced. Through the matter-element definition of UC substructure, the process model for the structure bionic topology design method based on biological UC is formed, which avoids the random or wild mental stimulation of the structure topology design method based on traditional substructure. In particular, in this proposed method, aiming at the problem about how to achieve the integration of high-efficiency load-bearing advantage of different organisms, furthermore, a biological UC hybridization method based on the principle of inventive problem solving theory (TRIZ) is proposed. The typical case is used to illustrate the process of this method in detail. The results from simulations and experiments both show that: the load-bearing capacity of structure design based on biology UC is improved than the initial design; on this basis, the load-bearing capacity of structure design is improved further through UC hybridization. All these show the feasibility and correctness of the proposed method.
ABSTRACT
Objective To assess the quality of iodized salt and investigate the urinary iodine level of pupils and women after implementation of universal salt iodization in Shijiazhuang city. Methods Between 2004 and 2008, nine salt samples were randomly collected from wholesale enterprises of 5 different directions of east,south, west, north and center in Shijiazhuang city every month. Meanwhile, eight salt samples, four urine samples of women, were randomly collected in each of the 8 households of 210 villages selected from 23 counties. Between 2004 and 2008, twenty urine samples of 8 - 10 year old pupils were collected in each of 160 schools from the 23 counties. Direct titration method was used for salt iodine determination, iodine concentration in urine was detected by the method of ammonium persulfate digestion-As3+-Ce4 + catalytic spectrophotometry. Results At wholesale level, the qualified rate of iodized salt was above 99%. At household level, the consuming rate of iodized salt was above 95%, and the rate of consuming non-iodized salt was less than 5%. The rate of qualified iodized salt was above 90% in every year except 2004(87.10%), and the rate of consuming qualified iodized salt was above 90% in those years except 2004(83.08%). Urinary median iodine level of both the pupils and the women was higher than 100 μg/L, and the rate of urinary iodine level that less than 50 μg/L was below 10%. Conclusions The quality assessment of iodized salt from wholesale companies and related indices of urinary iodine level of pupils, women and household iodized salt have already reached the national standard for eliminating iodine deficiency disorders.
