No abstract

Laser heat-treatment and laser nitriding were conducted on an AISI P21 mold steel using a high-power diode laser with laser energy densities of 90 and 1125 J/mm2, respectively. No change in surface hardness was observed after laser heat-treatment. In contrast, a relatively larger surface hardness was measured after laser nitriding (i.e., 536 HV) compared with that of the base metal (i.e., 409 HV). The TEM and electron energy loss spectroscopy (EELS) analyses revealed that laser nitriding induced to develop AlN precipitates up to a depth of 15 μm from the surface, resulting in surface hardening. The laser-nitrided P21 exhibited a superior wear resistance compared with that of the base metal and laser heat-treated P21 in the pin-on-disk tribotests. After 100 m of a sliding distance of the pin-on-disk test, the total wear loss of the base metal was measured to be 0.74 mm3, and it decreased to 0.60 mm3 for the laser-nitrided P21. The base metal and laser heat-treated P21 showed similar wear behaviors. The larger wear resistance of the laser-nitrided P21 was attributed to the AlN precipitate-induced surface hardening.

Improving the agricultural manpower structure is an urgent issue in our agriculture. The Young Farming Project is a major project of the youth farmer support policy, targeting young farmers who want to start a new independent farming by further developing the existing succession farm selection project. In our laws and regulations, agricultural holdings are defined as farmers and agricultural corporations, and individual economic units, such as youth successors, are targeted for support. However, since there are various individual economic units within the agricultural holdings, it is necessary to try the business target from various angles in the policy project to introduce new farmers from the outside. In this study, the production unit called the young successor farm, which has the characteristics of the production unit called the family farm, is identified as an individual production unit called the farmhouse, and its characteristics are examined through the concept of the family farm business. In Korea, we are used to understanding family farm and corporate farm as opposite concepts, but in the West, family farm and corporate farm are no longer viewed as opposing concepts due to the past debate on the existence of family farm, and the focus is on how family relationships and business activities are regulated within the farmhouse. By understanding family farm through the concept of a family business, it will be possible to provide a richer perspective for policy improvement in the future.