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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Jo Oct 27, 2022
The Korean people possessed of special love for their children had a custom of adorning the sleeves of their children’s coats with small pieces of coloured cloth.
Pieces of coloured cloth in rainbow-like harmony of colours ― mainly red, green, blue, yellow, pink, purple, white, etc. ― are usually attached to sleeves. Some of them are plain and some have patterns like flowers and butterflies and letters.
The breast of a rainbow-striped garment is decorated with striped or triangular pieces of cloth in various colours and the body is made in colours like green, jade green, yellow and pink for a good harmony of colours with the sleeves.
Rainbow-striped garments include saektongjogori, saektongkhunjogori, saektongmagoja, saektongturumagi, etc.
From ancient times, mothers in our country have dressed their sons and daughters in colourful coats and jackets distinguishable from casual ones on their first birthdays, which is a peculiar custom of the Korean people. Such customs are never found in other countries.
Since these clothes not only look beautiful and smart, but are to a children’s taste as well, they have been worn on first birthdays, birthdays and holidays and other visiting occasions.
The beautiful manners and customs peculiar to the Korean people have been improved by constant supplement of fresh elements over a long period and rainbow-striped garments have been developed into the ones representative of the national features.
Kim Kyong Il, researcher at the Academy of Social Sciences
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Jo Oct 26, 2022
In sedimentology, stratigraphic sequences and cycles are ordered by time spans and physical scales such as thickness, and bounded by discontinuities including unconformities or flooding surfaces.
Song Man Hyok, a section head at the Faculty of Earth Science and Technology, has proposed a spectral analysis method based on wavelet transform (WT) maxima and used it as a quantitative tool to identify multiorder stratigraphic boundaries and cycles in well log data.
The proposed spectral analysis is based on quantitative analysis of the center frequencies and resolutions of Gaussian wavelets in time and frequency, and it uses a combination of the WT maxima based on both the first order Gaussian wavelet with a high time resolution and the seventh order Gaussian wavelet with a high frequency resolution.
WT maxima spectra, which can characterize the evolution of WT maxima across scales and periods along WT maxima lines concerned with sequence boundaries, are used to detect dominant spectral peaks corresponding to the time-period domain WT maxima and to determine WT maxima spectral slopes.
The WT maxima spectral slopes are helpful for discriminating sequence boundaries from intrasequence cyclic variations in well log data, and the time-period domain WT maxima are used to relate the detected boundaries to relevant cycles.
He has introduced interval WT maxima spectra and stationary indexes related to the WT maxima spectra as indicators that could be used for hierarchical ordering of the boundaries and cycles.
Application of the proposed method to well log data shows that this method is efficient in identifying multi-order sequences that relate well to the Milankovitch cycles.
The detailed information about this is found in his paper “Spectral Analysis Based on Wavelet Transform Maxima: Identification of Multi-order Stratigraphic Boundaries and Cycles” presented to the SCI Journal “Mathematical Geosciences”.
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Jo Oct 24, 2022
Korean traditional dishes have developed in the course of a long history and they are widely-known to the world for their original flavor, aroma, appearance and colour and for their diversity in kind.
Korean traditional dishes have several good qualities.
First of all, Korean traditional dishes taste exceptionally good.
The original taste of each dish is guaranteed by several sorts of seasonings including soy, bean paste, peppered bean paste, sesame oil, garlic, spring onion and ginger harmoniously mixed with main ingredients ― various kinds of cereals, vegetables, fish, edible herbs, fruit, etc. that are grown in our country. For example, vinegared soy is used for oily dishes while vinegared hot pepper paste or mustard paste is used for slices of raw fish. Minced raw beef is mixed with sesame oil.
Secondly, Korean traditional dishes are wonderful in harmony of colour and delicious-looking.
Fruit of Schizandra chinensis or red pepper is used to make dishes red, and pine pollen or yolk of an egg is added for yellow colour. Green is made by wormwood or green soybeans, and black is made by black sesame or boletus. Fruit like ginkgo nuts or pine nuts are used to decorate dishes. Korean traditional dishes such as sinsollo, yakbap (sweet rice dish mixed with sugar, dates, chestnuts, pine nuts, sesame oil, etc.) and Pyongyang raengmyon (cold noodle) bring water to mouths for their natural colour and beautiful and good-tasting appearance.
Thirdly, diverse and scientific ways of cooking and cultural and hygienic ways of table setting are another feature of Korean traditional dishes.
Fermenting and aging like making kimchi, fermented rice cake and fermented fish together with boiling, baking, frying and stewing are the major ways of cooking, which not only make dishes delicious but also improve people’s health and prevent or cure diseases. As for table setting, cold and pungent dishes are served on small plates while those that are not pungent are put in large bowls. Besides, every food container has their lids for preserving the warmth and aroma of the contents and preventing them from going bad.
The last feature is the diversity.
The Korean people have lived on rice from olden times and the rice alone is made into many kinds including boiled white rice, bean-mixed rice, rice cooked with red-beans, bibimbap (mixed with spices, vegetables, meat, etc.), boiled millet, etc. They have made many kinds of rice cake as special dishes ― glutinous rice cake, rice cake steamed on a layer of pine needles, rice cake with flower patterns imprinted, cake made of rice flour and wormwood paste, steamed rice cake, etc. to name a few. Kimchi, which is original and widely known to the world, is diverse in its kind: whole cabbage kimchi, pickled sliced radishes, watery kimchi made of sliced radish, radish pickles with wild garlic, pickled mustard leaves and stems, etc. The number of Korean dishes is beyond enumeration ― dishes cooked in different seasons, those for traditional holidays and those cooked in different parts and so on.
Korean national dishes with a long history and tradition are still being developed and enriched in conformity with the aesthetic senses of the times and the demands of the people.
Pak Sung Gil, researcher at the Academy of Social Sciences
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