In commercial solar cells, the pattern of the front electrode is critical to effectively assemble the photo generated current. The power loss in solar cells caused by the front electrode was categorized as four types. First, losses due to the metallic resistance of the electrode. Second, losses due to the contact resistance of the electrode and emitter. Third, losses due to the emitter resistance when current flows through the emitter. Fourth, losses due to the shading effect of the front metal electrode, which has a high reflectance. In this paper, optimizing the number of finger on a 4 ´ 4 solar cell is demonstrated with known theory. We compared the short circuit current density and fill factor to evaluate the power loss from the front metal contact calculation result. By experiment, the short circuit current density(Jsc), taken in each pattern as 37.61, 37.53, and 37.38 mA/ cm2 decreased as the number of fingers increased. The fill factor(FF), measured in each pattern as 0.7745, 0.7782 and 0.7843 increased as number of fingers increased. The results suggested that the efficiency(Eff) was measured in each pattern as 17.51, 17.81, and 17.84 %. Throughout this study, the short-circuit current densities(Jsc) and fill factor(FF) varied according to the number of fingers in the front metal pattern. The effects on the efficiency of the two factors were also investigated.

건설업 사고사망율을 절반으로 줄이기 위한 정부의 노력에도 불구하고 중소규모 건설현장의 사망만인율은 감소하지 못하고 있으며, 중소규모 건설현장에 적용되는 대표적인 안전보건관리 시스템으로 공사금액 2억 원에서 120억 원(토목공사 150억 원)사이의 중소규모 현장의 시공자가 받는 재해예방 기술지도제도가 있다. 그러나 현장에서는 전문지도기관에 의해 실시되는 재해예방 기술지도의 실효성이 확보되지 못하고 있다는 지적이 지속적으로 제기되고 있다. 따라서 본 연구는 기술지도 제도의 문제점을 개선하고자 재해예방 전문지도기관 및 시공자를 대상으로 기술지도 계약에 대한 실태분석 및 계약체계의 문제점을 중심으로 설문을 실시하였다. 설문결과, 현재의 시공자와 재해예방 전문지도기관의 직접 계약에 따라 갑을 관계가 형성되고 이것이 공정한 기술지도 수행을 방해 하고 있는 것으로 분석되었다. 개선방향으로는 기술지도 계약의 주체를 시공자에서 발주자로 변경하는 것이 바람직한 것으로 제시되었다. 다만, 발주자의 전문성 부족 및 무관심으로 인한 문제가 발생할 수 있으므로 발주자에게 기술지도 이행에 대한 계약과 확인의 의무를 명확히 하고 저가 계약 문제를 해결할 수 있는 대가 기준을 도입할 필요가 있는 것으로 분석되었다.

This experimental study analyzed the reduction of the load capacity of the system support according to the uninstall bracing members by loading the ultimate load to the 3 - story system support assembly with the presence of bracing members as the key parameter. The load capacity of the 3-story specimen without bracing members is 38.4% of that of the 3-story specimen with bracing members. It is necessary to accurately reflect the installation plan of the bracing members and examine the structural safety of the system support assembly, not a single member, because there is a significant decrease in the load capacity of the system support assembly according to the uninstall of the bracing members.

This study examined the validity of the level of the earthquake load defined in the Korea specification for the tower crane which utilized the equivalent static load. The specification on the structure and performance of tower crane defined that the earthquake load should be considered as a horizontal load corresponding to 15 % of a crane self weight. However, this definition did not reflect the vibration characteristic including frequencies of the tower crane. Thus, it is necessary to carry out a study on the earthquake behavior of tower cranes that reflected the dynamic characteristic of earthquake loads and tower cranes. it was thought that the level of earthquake load defined in equivalent static analysis for the tower crane did not reflect the structural behavior of the tower crane correctly by overestimating the response from tower crane.