Application of the membrane process to wastewater treatment and reuse has been increasing due to water shortage, water pollution and an increase in water demand. Membrane fouling including biofouling should be controlled to extend its application. In this study, modulation of diffusible signal factor (DSF) system, the quorum sensing (QS) system that regulates EPS formation by microorganisms, was considered as a promising option to manage biofouling. Among many DSF compounds, cis -2-Decenoic acids (CDA) was selected. The experimental results showed that, as the CDA concentration increased, the density and number of stained cells decreased. The lowest density was observed when the CDA concentration of 300 nM was applied. The EPS on membrane surface decreased with increasing concentration of CDA. The CDA dosing also affected the EPS composition. At the 300 nM CDA dose, the total EPS reduced by up to 57% and the protein fraction by 35%. This study revealed the biofilm reduction effect of CDA under various conditions for MBR sludge. The application of CDA can be adapted to control biofouling in the MBR process.

This paper studied about effects of the certificate of ISO 9000 in the manufacturing companies whose number of employee is under three hundred. First, most of company answered that acquiring the certificate of ISO 9000 is very helpful for the company management. therefore the company has the competence in the change of domestic and international economy. Second, after acquiring the certificate of ISO 9000, there were many improvements in company culture, quality control and business process productivity. As a result, the acquisition of the certificate of ISO 9000 system makes the company culture preparing the future to become a world first class company.

양산단층이 지나는 한국 남동지방 지각의 QP-1 및 QS-1를 한국자원연구소가 설치한 9점의 지진관측소 자료를 바탕으로 확장 Coda 규격화법을 이용하여 구하였다 1994년 12월부터 2000년 2월에 일어난 근지지진에서 707개 지진기록에 대하여 1∼2, 2∼4, 4∼8, 8∼16및 16∼32Hz의 대역필터를 적용하여 분석한 결과, 각 관측점의 QP-1는 (7±2)×10-3에서 (5±4)×10-4으로, QS-1는 5±4)×10-4에서 (5±2)×10-4로 주파수가 1.5Hz에서 24Hz로 늘어남에 따라 줄어드는 주파수 의존성이 보인다. 이들 값의 지수 회귀선은 QP-1가 0.009(±0.003)f-1.05(±0.14), QS-1가 0.004(±0.001)f-0.75(±0.14))이다.

This paper studied two factors for the manufacturing companies whose number of employee are under three hundred. One is the effect of the observation of quality system under the CEO's interest degree of quality management. First, most of company answered acquiring certificate ISO 9000 is very helpful for the company management .therefore the company have competence for the change of economic environment of domestic and international economy. Second, after acquiring the certificate ISO 9000, there were many improvements in company culture, quality control and business process productivity. As a result, acquisition of certificate of ISO 9000 system makes the company culture preparing the future to become a world first class company.