Jo Feb 6, 2023
Washing holes is a very difficult and complex process that cannot be seen, so it must be proved experimentally.
Therefore, Han Chang Son, a researcher at the Faculty of Earth Science and Technology, employs a simulation device for flow of drilling fluid in his subject “Drilling fluid” to develop students’ creative thinking faculties by presenting principles and vivid images on washing processes.
The simulation device consists of hole models, a pipe rotary device, a cuttings supply device, a pump, a flow route, a fluid box and a control button.
As the simulation device aims to simulate the flow of drilling fluid and the movement of cuttings, he built two hole models in conformity with actual drilling conditions: Model 1 formed of high intensity rock and Model 2 formed of low intensity rock.
In the lesson, he puts the device in operation to show the students the processes of pressurized fluid supply through the rotary pipe and of cuttings conveyance along the annulus, the difference in the rising speed in the sections of various hole diameters and the process of accumulation of cuttings in widened drilling holes.
With the help of the device, the students are able to realize the following things: Cuttings are not transported out of drilling holes but move in their positions with spiral rotation movement due to pipe revolution. The higher the number of pipe revolution and the viscosity of drilling mud, the stronger the spiral rotation movement gets, so transportation of cuttings really goes well. In the formation with weak rock, hole diameters become wider because of erosion, which leads to the slowdown of the flow velocity and the accumulation of cuttings.
They are also able to find a way to improve drilling fluid processing methods.
...
Jo Feb 3, 2023
The monument to Mausoleum of King Kwanggaetho is a stone monument erected in 414 by his son, King Jangsu (25th king), in praise of the meritorious deeds of King Kwanggaetho, 24th king of Koguryo (ruling period: ３9１－４１２). The mausoleum is located 6 kilometres north-east of Kungnae Walled City (Jian City, Jilin Province), the second capital of Koguryo.
The monument is made up of a body stone and a stone pedestal. On the four sides of the smoothly processed body are drawn lines vertically and horizontally where letters are inscribed clearly. Only 1 530 of the letters written vertically in 44 lines are recognizable.
The words on the monument are largely divided into three parts.
The first part covers from the legend of the founder of Koguryo to the enthronement and demise of King Kwanggaetho. The second part deals in detail with the meritorious deeds of extending the territory of Koguryo performed by King Kwanggaetho. The third part regulates the number limit of mausoleum guards and the rules they had to follow.
The monument reflects the struggle and desire of Koguryo people for the unification of the three kingdoms. It also has a lot of valuable information that is not found in documentary records of political, social and economic situations of Koguryo, class relations, and relations with Silla, Paekje and Japan, etc. of that time.
The letters are written in a peculiar font, Yeso. The majestic and vigorous font demonstrates the lively and vigorous spirit of Koguryo people.
The monument gives an account of the vastness of the territory and the might of Koguryo, the eastern power. For its magnificence (longest and biggest of all grave stones made by our ancestors) and rich content, it proves to be precious cultural inheritance of our nation and important material for historical research.
Kim Son Yong, researcher at the Academy of Social Sciences
...
Jo Feb 1, 2023
Kim Chaek University of Technology (KUT), which has held the championship in every CodeChef challenge, has maintained its position in the CodeChef January Long Challenge, too.
The contest took place from 14 to 16 in January, 2023.
A total of 15 100 contestants from tens of countries and regions including our country, China and India took part in the contest which was divided into four ― Division 1 (over 70), Division 2 (over 540), Division 3 (over 2 900) and Division 4 (over 11 600).
Division 1 congratulated 29 winners including 8 KUT students.
This proves to be the prelude to successive victories in this year’s contests, just like the year 2022.
...
Jo Jan 31, 2023
Song Man Hyok, a section head at the Faculty of Earth Science and Technology, has proposed a new method to extract image features and to evaluate fractality based on two-dimensional (2D) continuous wavelet transform (CWT).
Multi-directional 2D CWT coefficients are used to determine the direction and magnitude of image intensity gradients directly unlike other methods using gradient components in horizontal and vertical directions. Image feature points are detected by comparing candidate directional 2D CWT coefficients at candidate points and their neighbors instead of gradient magnitudes or 2D CWT moduli used in traditional methods. It enables extracting multiscale image features including line singularities such as corners which are recognized to be hardly extracted by traditional methods. This offers an advantageous condition to study fractal objects consisting of lots of line singularities.
Assuming that the detected multiscale image features can reflect multiscale fractal measures used to evaluate fractality, that is, self-similarity across scales, he has proposed a method to evaluate fractality and calculate fractal dimensions using multiscale image features.
The application of the proposed method to theoretical fractal models proved that it is convenient and effective in extracting the image features of the models consisting of many line singularities and in calculating their fractal dimensions. It is concluded that the method is useful to deal with fractality evaluation of geoscientific objects such as coastlines and stream networks.
For more information, please refer to his paper “Image feature extraction and fractality evaluation based on two-dimensional continuous wavelet transform: Application to digital elevation model data” published in the SCI Journal “Fractals”.
...
Jo Jan 26, 2023
As well known, the time dependent Ginzburg-Landau (G-L) equations are a powerful tool for study on popular characteristics in nonlinear dynamics, especially the dynamics of magnetic vortices in a superconductor close to a critical temperature in a magnetic field.
Constant efforts to improve the critical properties of materials in type-Ⅱ superconductors and apply it into a variety of areas by forming artificial pinning centers are being made. Hence, it is of great importance to study the magnetic vortices in a superconductor with artificial pinning centers using the G-L equations.
In recent years, many works on superconductors with pinning centers and defects distributed in a fixed quantity and different forms have been conducted. However, the dynamic study of the magnetic vortices in a superconductor with randomly distributed pinning centers in a normal state has rarely been reported.
Ryu Yu Gwang, a researcher at the Faculty of Physical Engineering, has reported the simulation results on the dynamic behaviors of the magnetic vortices in the above mentioned superconductor by using the time dependent G-L equations.
COMSOL and MATLAB were combined for the simulation. The time dependent G-L equations were solved numerically using the PDE model of the COMSOL program. The pinning centers were randomly distributed on the whole area of the superconductor. Then a distribution function p(r), which was used to determinate the size and sites of the pinning centers, was defined in a MATLAB and was directly called during the calculating process by the LiveLinkTM for MATLAB in the COMSOL program.
First of all, he analyzed the magnetization curves and the density of superconducting electrons as a function of the external magnetic field along the z-axis.
The simulation result showed that the vortices configurations and magnetization depend on the content of pinning centers and that the maximum magnetization values decrease exponentially as the content increases. The analytic expression of the maximum magnetization values as a function of the content was -4πMmax/HC2≈0.24+0.175exp(-6.14ω). Therefore, it can be defined that the higher content, the more decrease in the diamagnetism of a superconductor.
Next, he determined the content of pinning centers with the largest mixed state by modeling the number of the magnetic vortices trapped in the pinning centers. According to it, the suitable content for trapping more magnetic vortices in a type-Ⅱ superconductor with pinning centers was 20%.
This work will be useful for studying and understanding the dynamics of magnetic vortices in a type-Ⅱ superconductor with randomly distributed pinning centers in view of the circumstance that they are randomly distributed in the superconductor during its fabrication.
...
Jo Jan 22, 2023
A research team led by Nam Sung Chol, a researcher at Mirae Academy of Science and Technology, has developed an agglutinated blood cell splitting flake with natural materials, which prevents aging by diluting thick blood.
If you wear it on your skin, you can keep yourself in good health without taking medicines or injections. It is very useful for middle-aged and elderly people.
The research team activated natural minerals with good property of far infrared radiation and mixed several additives, thus fabricating material with excellent radiation property. Then, with these materials, they continued to develop an agglutinated blood cell splitting flake, a simple functional health product that improves life activities and cures diseases by diluting thick blood.
The product radiates far infrared rays (2.5-15 ㎛) corresponding to the intrinsic absorption wavelength band of body cells and tissues with high efficiency, generates a large number of anions to improve the circulation of blood, restores the pH of the body to normal level (7.35-7.45 pH) and facilitates the uptake of nutrients and excretion of waste from the body.
Hence, it helps to prevent and treat various diseases if it is worn regularly.
By improving the microcirculation of blood, it activates the metabolism of organ tissues and it has good effect on headaches due to geomagnetic phenomena and circulatory disturbances, autonomic ataxia, limbs numbness, stress disorders due to excessive mental labor and on removing harmful cations due to electromagnetic waves from a long time of being in front of computers and televisions. It also stabilizes blood pressure, improves dyslipidemia (high hypolipoproteinemia, low hyperlipoproteinemia) and prevents stroke sequelae such as cerebral thrombosis and cerebral infarction.
After one to three months of wearing it, it proves to be effective: the face looks healthier and the skin gets elastic.
It is on a daily increase in its demand.
...