The rapid development of modern industry requires products with good mechanical properties and light weight, and thus, the application of Al and its alloy attracts a great deal of attention. However, the production of Al products is surely associated with melting process, in which the formation of oxide inclusions and the absorption of gases like hydrogen are inevitable owing to the oxygen and water vapor in the air. These impurities in molten aluminum have unfavorable influence on the quality of aluminum products. These defects are found in melting and casting processes and therefore, it is of great significance to investigate the influence of inclusions and gas in molten aluminum on the quality of aluminum products and to develop a refining method to remove them.

In order to remove inclusions and gas in molten aluminum, several methods are being used. Among them, refining by solid refining agents is considered most effective from the viewpoint of process operation and economical effectiveness. For solid refining agent, alkaline metal salts in the type of chloride including NaCl and KCl are widely used, and fluorides including NaF, AlF₃, MgF₂, Na₃AlF₆, CaF₂, Na₂SiF₆, NaBFO₄, etc. are also used.

Many researchers reported the composition of chloride-fluoride system refining agents, and most of them focused on the removal of oxide inclusions. However, there are few investigations related to the appropriate composition of refining agents and the changes in their melting point for the removal of gas, which greatly affect the mechanical performance of pure aluminum products like aluminum sheet.

Sin Hyok, a section head at the Faculty of Metallic Engineering, selected a chloride-fluoride system refining agent as a solid refining agent for removing oxide inclusions and gases to investigate the acting mechanism of each component and determine the optimal composition ratio, and estimated the adaptability of the new agent by measuring its melting point.

The chlorides were NaCl and KCl and the fluorides were Na₂SiF₆ and NaF, and the optimal ratio of NaCl, KCl, Na₂SiF₆ and NaF was about 44, 33, 12 and 11%, respectively.

A mine-drilling rig is widely used in mine workings and its operational efficiency is increasing. It not only should have long penetration length and high torque but also could fix various drilling accidents. In addition, its size should be optimized for assembly to meet coal mine conditions.

Choe Kum Hyok, a researcher at the Faculty of Earth Science and Technology, has designed and constructed a mine-drilling rig suitable for the coal mine conditions in our country, for which he conducted an optimal design of drilling and rotary systems and a stability design of drill pipe pillars.

The mine-drilling rig requires a relatively small space for drilling operations, which can ensure good drilling operations in the conditions of anthracite coal mines in our country with fairly small mine cross-sections. In addition, it needs few high-precision parts and it is easy to manufacture and cost-effective. Since its torque and WOB are relatively big and it can maintain high stability during drilling, it can be used for various purposes including degassing, drainage and exploration wells. And its randomly controllable angle of azimuth and inclination in one position increases penetration efficiency.

Originally, the word sinsollo was the name of a vessel with a unique structure used to boil foods. Many years later, the name of the vessel came to indicate the food boiled in it.

Sinsollo is well-known to the world as a representative dish of the Korean cuisine, which has the best taste as if dainties of all lands and seas are put into one vessel and is also appealing to the eyes. Its broth is mainly made of chicken and fish and meat are used with gingko nuts, pine nuts, chestnuts, jujubes and walnuts.

Dozens of kinds of ingredients are used to make the dish.

Sinsollo is served with individual bowls as it is shared by several people.