Jo Nov 6, 2022
“Structural engineering of thermal facility” is a subject which studies theories and techniques related to the design, fabrication and structural safety of thermal power facilities.
In the past, the cognitive faculty and the level of 3D design and structural analysis of students were low due to the lack of concrete images of thermal power equipment.
Pak Un Hyok, a researcher at the Faculty of Heat Engineering, has introduced practical 3D models and applications to his subject to ensure high cognition effect and application ability whereby students could satisfactorily solve problems arising in reality.
Firstly, he has presented practical problems for their individual tasks and asked them to solve them by using application codes.
Secondly, while giving theoretical knowledge, he has taken some minutes in his lecture to explain solutions to practical problems by application codes.
With a brief introduction of the mathematical induction, he has given detailed explanations of the ways of solving problems by ABAQUS and the results so as to enhance students' cognition and application faculty.
Thirdly, for better cognition effect, he has created, collected and edited real objects and models of ordinary thermal power facilities.
All these have proved useful in increasing the teaching intensity and the creative thinking ability of students.
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Jo Nov 4, 2022
Okryugum was invented in the 1970s as an original national flick instrument by developing wagonghu, one of the old national instruments that had been passed down from ancient times. Chairman
Okryugum consists of the body made up of a resonance box and tune adjusting pedals, and the legs. The seven tune adjusting pedals attached to the legs make variations possible in any conditions. It has a total of 33 strings. It has two bridges on the resonance box; one on the front side and the other on the eight pillars at the back.
Okryugum is a C instrument which ranges from C2 to G4. There are seven pedals that are arranged in order of C, D, E, B, A, G and F from the left.
Okryugum produces clear, elegant and beautiful tones true to the meaning of its name. Its tone is so diverse that a single pluck sounds like a harp, a piano, a kayagum or a guitar. Such tones blend well to produce a silvery one. Since it fully supports a chromatic scale and vibratos like a kayagum, it is regarded as a unique and excellent national instrument with a great power of expression. It is used as a solo instrument and plays an important part in a national instrument ensemble as well as in guaranteeing the national colouring and sentiment of the mixed orchestra of a Juche type with extraordinary tones and ample volume.
Ri Yong Ho, section head at the Academy of Social Sciences
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Jo Nov 2, 2022
“Device Driver” is a subject which deals with design technology of a program controlling peripherals connected to a computer system and interfaces.
In the past, when they taught general structures and programming methods of a character device driver, a block device driver and a network device driver, teachers failed to refer to individual devices in close combination with a control program. Without suitable examples found in reality, students confined themselves to getting a general understanding of the programming method, far from gaining knowledge of devices used in practice.
Kim Kuk Song, a researcher at the Faculty of Information Science and Technology, has associated his subject “Device Driver” with an embedded system, thus overcoming above-mentioned shortcomings.
First, he presented the information about Linux device driver of the embedded system in his teaching plan and gave specific examples in order to raise cognition effect.
As a device driver depends on I/O management of the operating system, he gave a general outline of the functions supported by Linux kernel in each section and explained with concrete examples which devices of the embedded system needed such functions.
Second, he organized practice hours in a way that students could consolidate what they learnt in lectures and develop their skills whereby they could write device drivers needed in reality by themselves.
The practical teaching content helped students understand how to write a device driver, but it still left those with lack of experiences with difficulties in practice.
Therefore, he applied a teaching method to help students to plan, design, make and control device drivers by themselves.
The first thing he did was to decide practice tasks for students to put their knowledge to practice and to show how a device driver worked in an embedded system so that students would be aware of the scale and capacity of a design object and the technological requirements to be solved. The next thing was to provide them with up-to-date data related to an embedded system so that they could select properly by themselves necessary handbooks, drawings, electronic circuits, example codes for a device driver, etc.
Until a device driver was finished, he repeatedly explained the building of cross development environment, translation, debugging, porting and downloading of source codes to the embedded system, and running methods.
As mentioned above, theoretical teaching contents on I/O management in an operating system combined with the structure and operation of peripherals and a device driver for controlling them and display of the operation of a device and a driver based on an actual one raised cognition effect among students. Students could develop their ability of utilizing the development kit for an embedded system while trying to develop device drivers by using a computer and an embedded device.
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Jo Nov 1, 2022
A mask dance that has been enjoyed by the Korean people is the oldest of all Korean folk dances. The mask dance evolved from a hunting dance that primitive people used to do wearing animal masks.
An animal mask dance was dominant in the primitive and ancient times, while a human mask dance that gave a vivid description of human life was also popular in the period of the Three Kingdoms. Some of the human mask dances were painted on some murals of the Koguryo tombs and some others were similar to “Kiak Dance” of Koguryo and Paekje. In the period of Palhae and Later Silla, there were several kinds of mask dances like Dragon Mask Dance of Palhae, “Choyong Dance” of Later Silla, Lion Mask Dance described in “Hyangak 5 Dances”, Woljon, Sokdok and Taemyon. During the Koryo dynasty, the mask dance became more diverse in kind and mask dance dramas that showed historical facts as they were also became fashionable. During the feudal Joson dynasty, the mask dance performed by village dancers, developed into a folk dance with provincial features. The mask dances in the latter half of the feudal Joson dynasty are classified with each local distinction into Pongsan Mask Dance and Haeju Mask Dance in Hwanghae Province, Lion Mask Dance in Phyongan Province and Hamgyong Province, Sandae masked drama in Kyonggi Province, Ogwangdae Dance and Field Dance in Kyongsang Province.
The folk mask dance loved by our people is valuable heritage of our national dance and an excellent cultural treasure that deserves to be boasted of to the world. As mask dances were performed mainly on outdoor stages, movements of arms and legs rather than acting or words raised artistic influence by giving a vivid and skillful portrayal of life.
To sum up, the Korean mask dance is one of the precious legacies of national culture with a long tradition and rich contents that represents the national aesthetic sense and emotions by dint of diverse and unique dancing techniques, and it is still widely danced with eternal viability.
Kim Son Yong, researcher at the Academy of Social Sciences
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Jo Oct 30, 2022
Perovskite solar cells (PSCs) are the next generation of photovoltaic technologies that use inorganic-organic hybrid perovskite of ABX3 type structures as light harvesting materials.
Most transparent electrodes for flexible PSCs are made of indium tin oxide (ITO). Although these ITO transparent electrodes have high transparency and conductivity (80% and 15Ω/m2, respectively), they have a number of problems including limited indium sources, high cost due to deposition techniques (sputtering, evaporation and pulsed laser deposition, etc.) and high mechanical brittleness.
Since transparent conductive films based on AgNWs show excellent performance such as high optical transmittance and low sheet resistance along with simple fabrication process and excellent mechanical flexibility, they have been deemed as the most promising alternative to ITO.
However, the transparent electrodes made of bare Ag nanowire networks have a rough surface and the gaps between silver nanowires cause serious parasitic lateral current flow, which leads the performance of devices to the dramatic failure.
Jon Sang Mo, a researcher at the Faculty of Applied Chemistry, has resolved problems with incorporating AgNW networks into PSCs such as smooth surface morphology, space filling and chemical stability, by employing solution-deposition of conductive ATO nanoparticles onto pre-existing AgNW networks at low temperatures.
The PET/AgNW/ATO composite transparent electrodes showed a transmission of 76–82 % in the visible region with an excellent sheet resistance of 18Ω/m2, similar to the commercial PET/ITO plastic substrates.
To build up flexible PSCs, he adopted the simple architecture, in which the CH3NH3PbI3 thin film was sandwiched between ZnO (as the electron-selective layer) and the carbon electrode (as the hole-selective layer) on the AgNW/ATO composite transparent electrodes.
Under AM 1.5 G and 100 mW/cm2 simulated sunlight illumination, the flexible PSCs based on AgNW/ATO composite transparent electrodes achieved PCEs of 5.07 %. JSC, VOC, and FF were 9.8mA/cm2, 835mV and 0.62, respectively.
The new fabrication technique on such a cheap transparent electrode could advance the roll-to-roll mass production of flexible low-cost PSCs.
You can find detailed information about this in his paper “Flexible perovskite solar cells based on AgNW/ATO composite transparent electrodes” presented to the SCI Journal “Synthetic Metals”).
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Jo Oct 28, 2022
Son Won Chol, an institute head at the Faculty of Materials Science and Technology, who successfully developed a new method of hardfacing a worn drill bit by using a build-up electrode with coatings such as nitrided ferrochromium and WC, has been working hard to make further achievements.
In the past, build-up electrodes with Fe-Cr-V-Mo-Ti, Fe-Cr-Mn-V-Ti and Fe-Cr-W-V were used to repair a drill bit for drilling rocks of low strength (f<5).
In general, a hard alloy with high bending strength is used to drill hard rock thanks to its high stability on impact load and that with low bending strength is used for soft rock.
What he used to develop build-up material of the drill bit with high bending strength and toughness was Fe-Cr-Mn-V-Ti-WC system alloy.
He added WC and nitrided high carbon Fe-Cr in coating flux to form a large amount of carbonitride in weld metal for improving the bending strength and toughness.
Based on the effect of the content of ferro-alloys on the hardness and bending strength of weld metal, it was found that the reasonable contents of ferro-alloys to ensure HRC 62 and bending strength of 480MPa were nitride ferrochromium of 37%, ferromanganese of 8%, ferrotitanium of 8%, ferrovanadium of 8% and tungsten carbide of 12%.
Then, considering the effect of weld layers on the microstructure and properties of weld metal and the geometric dimension of the drill bit, he selected two weld layers and heat input 14.20kJ/cm. Finally, he could ensure hardness of weld metal HRC64.
This method can be used to deposit a worn drill bit at coal mines and mines where the strength of rock is medium (f=5~8).
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