Jo Mar 11, 2022
Yu Chol Min, a researcher at the Faculty of Metal Engineering, has been using anecdotes and practical data in physical chemistry to help his students have a better understanding of concepts and formulae given in the lectures. As a result, they have been able to grasp the main points of his lectures and to improve their practical abilities.
Physical chemistry is a subject which deals with the relation between physical and chemical phenomena occurring in metallurgical processes, and its contents are mostly related to abstraction and theory. For this reason, if the lecture is focused on explanation of theories, derivation of formulas or calculation, students will find it difficult to have a notion of what they are learning and it may lead to the decrease in their enthusiasm for study.
Therefore, he decided to invent some methods to stimulate students’ interest and enthusiasm and to provide them with a vivid notion.
To start with, he used the method of telling anecdotes about famous scientists to improve the understanding of concepts and formulas given in the lectures.
Even a single concept, a law or a formula came into being through the efforts of many scientists and it involved corresponding anecdotes.
If students are told certain anecdotes related to a notion or a formula, they can get to know about the history and mysterious background of them and understand them more easily.
For instance, he used the following anecdote in the lecture on the second law of thermodynamics.
The efficiency of the steam engine made by Watt in 1770s was less than 10% and it wasted a large amount of heat energy. So scientists tried to make a perpetual machine which would convert the whole amount of heat energy provided by a single heat source to completely different kind of energy.
“Zero motor” which a scientist attempted to design is a typical example. According to research, if the heat diffused in the process of lowering the temperature of about 109km3 of the sea water on the earth by 0.25℃ was converted into energy, 1015kW of electrical energy would be produced, which is said to be quite enough for the whole world to use for as long as a thousand years.
He wondered if he could get mechanical energy from the steam released when liquid ammonia in a cylinder was gasified by such a huge amount of heat energy, and liquefy it back. Then, he was planning to make a motor which produces energy constantly through this cyclic process. However, his idea turned out to impossible and his effort was in vain since gasified ammonia can never be liquefied on its own.
In addition to him, many scientists attempted to make a perpetual machine for many years, but they all failed. In the meantime, an idea came into their minds. They wondered if the impossibility of making a perpetual machine might serve as a kind of law that explains the natural world. That was formulated as the second law of thermodynamics in the middle of the 19th century.
Such a historical fact related to a perpetual machine stimulated students’ interest in the second law of thermodynamics so they could have a scientific understanding of what a perpetual machine was and why it was impossible to make it.
Next, he led students to grasp the gist of the lecture by themselves and to improve their practical abilities by giving a scientific solution to the problems they usually come across in their daily life.
The examples closely connected to new knowledge and often seen in daily lives could improve their faculties of inquiry and creation and make them realize the significance and value of their knowledge by leading them to the world of physical chemistry.
We can take the lecture on the kinetics of heterogeneous reaction as an example.
Explaining the kinetic difference between homogeneous and heterogeneous reactions like solid-gas, solid-liquid and solid-solid, he presented a question, “Why do they burn powdered coal instead of lump coal in the boilers at thermal power plants?”. Then the students answered that the combustion of powdered coal is faster than that of lump coal because the surface area of powdered coal is larger.
He continued explaining that powdered coal flew about in rotary kilns, which resulted in a great loss, and that it raised the issue of forming it into small grains. Then he set forth a question for this and led them to its solution.
Therefore, the students could have chances to apply what they had learnt to practice and try harder to acquire more knowledge.
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Jo Mar 9, 2022
Jong Song Dae, a lecturer at the Faculty of Social Sciences, has been enhancing cognition efficiency by telling funny and persuasive short stories at appropriate time in his lecture.
Witty humour that teaches you something meaningful along with laughter with great persuasive power has greater influence than any kind of wordy speeches or writings.
In psychology lectures that help students to do successful work with people on the basis of the scientific understanding of various psychological phenomena and laws formed among people, he applied humour effectively to enable them to understand what they learnt in a plain way and to raise their faculties of thinking and eloquence.
Firstly, he found as many short stories as possible helpful to develop students’ thinking and told them at appropriate time, thus raising the level of popularity. In other words, he found good examples relevant to the content of the lecture and applied them.
For instance, “Baby’s job” was told in the lecture on the process of formation and development of human psychology, and “Did the cocks celebrate the New Year’s Day in such cold weather?” in the lecture on a desire.
He also collected a lot of short stories for the development of thinking and set occasions for appropriate application.
For example, he chose “The latest tooth” and “An expert in poultry” for types of thinking, “Oral thanks” for reaction of feelings, “Repeated rudeness” for types of hobbies and tastes, and “Pride of a squad leader” for types of human relationship.
Secondly, he raised cognition efficiency by making students analyze stories by themselves.
For example, in order to help them to have an understanding on their own of the formation and development of psychology in the childhood, he started with telling “I need more fingers.”.
It goes as follows.
A mother was teaching arithmetic to her 5-year-old son.
Mother: How much is eight plus five?
Son: Mum, I need more fingers…
He let students analyze it in their own ways.
Their argument produced several analyses: the child was not able to count it because he had only 10 fingers, the child was unable to count it because he had not learnt to count numbers over 10, that is, he did not know that he could spread out his fingers for continuous counting after counting to 10, etc.
As a result, they could grasp the gist of the lecture easily which said that in the childhood thinking is restricted to those that have immediate relation to the objects they can perceive and imagine at the moment and that object motion-centred thinking develops into intuitive depictive thinking.
As mentioned above, the employment of humour made it easier and faster for students to understand what they learnt, and heightened the faculties for its practical application to the life.
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Jo Mar 7, 2022
Kim Hwang Won was a well-known poet in Koryo. Touring the scenic spots in our country, he composed a number of poems about the beautiful scenery.
One summer he climbed the Moran Hill to the Pubyok Pavilion overlooking the beautiful mountains and rivers in Pyongyang. Gazing at the Taedong River of translucent blue skirting round the Chongryu Cliff and the Walled City of Pyongyang, and East Pyongyang spread out endlessly in mist, he just stood still for a long while, enchanted by the magnificent view.
(I have never seen such wonderful scenery before!)
He was lost in appreciating the beauty of the landscape.
He was maturing his idea of a poem for a good while with his arm on the pillar until finally he started driving his writing brush catching the eyes of a crowd of people surrounding him.
Even though he wrote down a few lines at a go without difficulty, he was prevented from carrying on.
After some minutes of looking down from the pavilion with the brush in his hand, he made another attempt. However, he found it more and more difficult to continue with the poem. When he looked far down at the translucent blue waters of the Taedong River from the Pubyok Pavilion, he felt as if he was standing on the pavilion in “the Palace of the Sea God”, which sprang high above the sea, and looking over the Tongdaewon Field veiled in mist made him feel like standing on the balcony of “the Palace in Heaven” floating over the clouds. He found his talent was far from the charming scenery that struck him with a fresh impression everytime.
All of a sudden, he broke the stem of his brush and wept smacking his hand down on to the floor.
“Ah, I am not talented enough to depict the beauty of Pyongyang!”
Lamenting over the lack of his talent, he continued weeping until late at night before he left there. Later, the people in Pyongyang kept his unfinished two-line poem hanging on the pillar of the pavilion and at present it is seen on the column of the Ryongwang Pavilion. That is Kim Hwang Won’s unfinished poem “On the Pubyok Pavilion”.
The reason why they hung his poem on the pillar of the Pubyok Pavilion lies in the fact that they wanted to be proud of the beauty of Pyongyang generation after generation, which even a famous poet could not find enough poetic words to depict as well as the fact that it was well-written.
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Jo Mar 3, 2022
Hunminjongum, invented in the 15th century, is the national alphabet of our own.
As it is literally interpreted into “correct sound for teaching common people”, it means “a fine alphabet to write the correct sound for teaching common people”.
Our people had used Ridu characters (Chinese characters used for their sound values to write Korean particles, endings and auxiliary verbs in order to facilitate the reading of Chinese texts) since the period of the Three Kingdoms, when Hunminjongum, the most advanced alphabet, was invented in 1444.
In those days King Sejong commissioned several scholars at Jiphyonjon (supreme research institute in the feudal Joson dynasty) like Jong Rin Ji, Sin Suk Ju, Song Sam Mun, Choe Hang, Pak Phaeng Nyon, etc. to do research into making characters.
They succeeded in making our own characters in January, 1444 (December, 1443 by the lunar calendar) and made it public to the world as Hunminjongum.
When it was invented, it consisted of 28 letters, with 17 initial sounds and 11 medium sounds.
It has several superior properties.
It makes it possible to give a vivid expression of our feelings at will as well as to express all sorts of sound in letters
Moreover, it is easy to learn and use as it is based on a scientific principle and on a certain system.
The invention of Hunminjongum is of great historical significance since it not only provided possibility to establish the standards of the national language and to ensure the oneness of our linguistic life but also demonstrated the scientific wisdom of the Korean nation, developed the national culture and further enriched the heritage of our language culture.
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Jo Mar 1, 2022
The contests ended on February 14, 2022.
The first contest was held from 4 to 7, February. About 22 300 contestants from tens of countries and regions including our country, China and India took part in it. 210 belonged to category 1, 3 191 to category 2, and 18 902 to category 3. 5 problems were set forth in category 1, none of which were challenge problems.
A total of 38 contestants won the first place in category 1 – 19 from the DPRK, 2 from China, 4 from India, 2 from Vietnam, 1 from Singapore, 1 from Germany, 1 from Portugal, 3 from the UK, 2 from the US, and 3 from Japan.
8 out of the 19 winners of our country are students at Kim Chaek University of Technology.
Our country accounts for the half of the world winners, and our university 21.052%, which rises to 42.105% in our country.
In the meantime, 1 from KUT took the first place in category 3.
The second contest went on from 11 to 14.
About 19 300 contestants from tens of countries and regions including our country, China and India took part. 170 belonged to category 1, 2 433 to category 2 and 16 755 to category 3. 4 problems were presented in category 1, none of which were challenge problems.
A total of 30 contestants in category 1 won the first place – 19 from our country, 2 from China, 5 from India, 1 from Argentina, 1 from the UK, and 2 from Japan.
All of the 8 students from Kim Chaek University of Technology took the first place in category 1.
19 winners from our country constitute 63.3% of the world winners, In the meantime, our university amounts to 26.67% in the world and 42.105% in our country.
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Jo Feb 25, 2022
Ri In Sik, a researcher at the Semi-conductor Institute, made an analysis of reverse voltage distribution of high-voltage diode stack considering the effect of temperature.
First, he presented an equivalent circuit of a high–voltage silicon diode taking into account the effects of temperature and reverse voltage, and obtained an analytical expression for impedance of a diode. Then, he proposed the most generalized equivalent circuit of a high–voltage diode stack consisting of a serial connection of several diodes, and obtained an analytical expression for the reverse voltage applied to each diode. As a result, he offered an easy estimation of the reverse voltage distribution of a high–voltage diode stack by an analytical method, not in an experimental way.
High–voltage diode stacks (HVDS) are now widely used in extracorporeal shock wave lithotriptors, diagnostic X–ray equipment, sound detectors, night glasses, high–voltage magnetic compression modulators, high–voltage pulse generators, dust collectors and electrostatic fly–ash separators at thermal power plants.
The most important characteristic of an HVDS is reverse voltage distribution between chips or diodes. If the non–uniformity of reverse voltage distribution is severe, twice the breakdown voltage of P–N junction or more can be applied to the chips or diodes placed on high–voltage terminal and ground terminal, leading to their destructions. The reverse voltage distribution of an HVDS is mainly affected by the characteristics of chips or diodes, such as the dependence of the temperature and the reverse voltage on the impedance of them. The dependence of impedances of chips or diodes on temperature and reverse voltage strongly affect the reverse voltage distribution of an HVDS. Also, according to an HVDS consisting of stacked chips or a serial connection of individual diodes, the leakage impedances connected to the high–voltage terminal and the ground terminal are varied and they strongly affect the reverse voltage distribution. The stacking of chips and a serial connection of the individual diodes are the technologies that have been widely used to manufacture HVDS.
The reverse current of the diode increases and its barrier resistance decreases with increasing temperature and reverse voltage. In addition, when the reverse voltage of the diode increases, the width of the space–charge layer increases, thus the barrier resistance decreases. Consequently, the impedance of the diode decreases with increasing temperature and reverse voltage. Hence, the equivalent circuit of an HVDS consisting of a serial connection of the individual diodes is needed in order to analyze the reverse voltage distribution of it, considering the effects of the temperature and the reverse voltage of the diodes.
That is why, he proposed and analyzed a new equivalent circuit of an HVDS, including not only the impedance and the uniform voltage impedance of each device, but also the leakage impedance connected to the high–voltage terminal and the ground terminal.
The calculated values of the reverse voltage distribution of a high–voltage diode stack were shown to be in good agreement with the measured values.
His essay “Analysis of Reverse Voltage Distribution of High–Voltage Diode Stack Considering Effect of Temperature” is carried in SCI Journal “Solid-State Electronics”.
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