Jo Jun 12, 2026
Dynamic chemical plating has been developed to overcome the disadvantages of conventional electroless plating (plating bath control, solution life limitation, difficult plating for large products, plating rate around 5㎛, etc.). Dynamic chemical plating can be employed for single metal plating such as copper, nickel and silver as well as alloy plating including Ni-P and Ni-B-P, and composite plating including Ni-B-P-graphene composite coating. Silver coating layers by the dynamic chemical plating are widely used for silver mirrors, electromagnetic shielding, and consumer goods production.
Ri Ju Chon, a researcher at the Faculty of Chemical Engineering, has experimentally studied the effect of silver concentration, ammonia water concentration, formaldehyde concentration, pH and temperature on the plating rate of dynamic chemical plating, and derived a relationship equation between each parameter and the rate by least squares approximation.
As the relative error between actual measured rate and calculated rate using the equation is less than 15%, the rate equation is considered useful for controlling plating process and clad thickness.
For further details, you can refer to his paper “Derivation of the Rate Equation of Silver Plating by Dynamic Chemical Plating” in “Proceedings of KUTIC-2025”.
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Jo Jun 11, 2026
Chlorination not only complicates the after-treatment process by dissolving some or most of the sulphides in the treatment of sulphide ores, but also increases the consumption of oxidizing agents such as chlorine gas. In addition, the stability of gold chloride complexes is not high, and when in contact with other reducing agents (sulphides in ores or products of low oxidation states produced during oxidative decomposition), it can be easily redeposited to significantly reduce leaching rate. Therefore, chlorination is relatively suitable for acidic ores with sulphur content less than 0.5%, and generally, pre-treatment and oxidative desulfurization are necessary for gold-bearing sulphides.
Kim Chang Sok, a researcher at the School of Science and Engineering, has proposed a new environmentally-friendly gold chlorination hydrometallurgy process consisting of pressure oxidation pretreatment, chloride leaching and ion exchange resin adsorption of high-sulfur refractory gold concentrate, identified necessary indices through basic research, and provided basic data for the application of environmentally-friendly non-cyanidation of refractory gold concentrate.
The highest gold leaching rate of about 96.54% was obtained when the pressure oxidized residue of refractory gold concentrate was chlorinated at pH=4, sodium hypochlorite concentration of 0.5%, sodium chloride concentration of 75g/L, temperature of 30℃, liquid-solid ratio of 3:1 and time of 120min.
For more information, you can refer to his paper “New Method of Environment-Friendly Chlorination Hydrometallurgy of Refractory Gold Concentrates” in “Proceedings of KUTIC-2025”.
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Jo Jun 10, 2026
Optimization of tool path and cutting condition is very important in different kinds of machining for reducing machining time and improving machining accuracy.
In general, a machining centre has an ability to provide sufficient manufacturing precision and efficiency with high adaptability for various types of machining features, but it does not have a function of selecting the optimum tool path for the achieved cutting speed.
Many studies have been conducted for the optimization of tool path in different kinds of machining. Special attention was paid to drilling, one of the most widely used metal machining, and many experimental and mechanical approaches were presented for modelling cutting force based on drill geometry and cutting conditions.
Kim Myong Il, a section head at the Faculty of Mechanical Science and Technology, has proposed an optimization method for drilling the hole clusters in a machining center (MC) on the basis of a cutting force model, in which the tool path is optimized to reduce machining time and power consumption, and cutting condition is optimized to improve machining accuracy. He obtained a predictive model of cutting force from drilling tests using multigene genetic programming (MGGP).
He applied the proposed method to MC for machining trolleybus underframes so that it could provide high machining accuracy and long tool life as well as shorter machining time and low power consumption.
You can find the details in his paper “Optimization of Tool Path and Cutting Condition based on Model of Drilling Force in the Machining Center” in “Proceedings of KUTIC-2025”.
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Jo Jun 9, 2026
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.
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Jo Jun 8, 2026
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.
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Jo Jun 5, 2026
The increasing amount of text found in all areas including articles, magazines, research papers, academic seminars, etc. calls for a proper way to easily and effectively interpret large volumes of text. From these requirements, word cloud has emerged as one of the new techniques for obtaining and displaying the most meaningful words.
Word cloud is a form of graphical display that allows users to easily communicate with text, documents, etc., so that they can easily and efficiently understand them in a short time. In the word cloud, high-weight words are placed preferentially. That is, the heaviest word is put in the center, around which the remaining ones are placed. To visualize word clouds, many visual attributes such as font size and color were used. Here, font size was given prior importance. Frequent terms are easily found in the word cloud due to their large font size.
Generally, many tabular forms are used to visualize the content of a database. This form is effective for reflecting a certain situation, but it does not accurately reflect the degree of association between data and, moreover, it is difficult to visualize the degree of change in the data as it is shown continuously.
Jong Chol Sam, a researcher at the Faculty of Information Science and Technology, has proposed an approach to optimize cloud placement of words based on the estimation of similarity between words using the structure of database and the clusterizing by similarity matrix.
First, he performed a similarity evaluation using database structure and carried out a clustering by similarity matrix of words. Then, he determined the font size and bounding box from the weight of words and optimized the word layout on the 2D canvas.
The experimental results show that when the content of database is displayed as a word cloud by the proposed method, users can quickly acquire information that reflects the semantic relations of data and a lot of information can be displayed in less space.
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