Jo May 14, 2023
A research team led by Jang Tae Il, a researcher at the Nano Physics Engineering Institute, has developed an ozonated water generator by water electrolysis.
Ozone has widely been applied to wastewater treatment and drinking water disinfection due to its significant oxidative property. Especially, O3 dissolved water, ozonated water, is used as a disinfector. There are two methods to produce ozonated water: dissolving gas phase ozone in water and on-site generation by water electrolysis. The advantage of water ozonation by water electrolysis is higher concentration of ozone than other methods.
To make an ozonated water generator by water electrolysis, they developed a nanocomposite catalyst whose ozone evolution efficiency is significant, and determined the factors that affect the efficiency.
The generator consists of an electrolytic device and a power supply unit.
The electrolytic device is a couple of electrodes where an anode and a cathode are spaced. When it is immersed in a water tank and connected to the power source, ozone, oxygen and hydrogen are evolved. Here, α-PbO2, F-doped β-PbO2 and graphene electrodeposited on the stainless steel mesh are used as an anode, and a pristine stainless steel mesh as a cathode.
Galvanostatic switching power supply is used as a power source.
They determined various factors such as an electrode gap, the temperature of electrolyte, current density, kinds of ions in tap water, etc. affecting the ozone evolution by water electrolysis, and they guaranteed generation of up to above 15mg/L of dissolved ozone concentration of ozonated water at the optimum operating condition.
This technology will widely be used in various fields such as wastewater treatment and disinfection for prevention.
...
Jo May 12, 2023
A real-time distance education system has been developed by Kim Chung Min, a researcher at the Faculty of Distance Education.
It is an education support system that enables real-time audio-visual communication by computer devices such as IP cameras, USB cameras and microphones. It supports teaching planning, group discussion, desktop share, e-board share, streaming multimedia, online test, teaching evaluation, etc.
A real-time campus distance education system must be able to support a lecture for a large number of distributed students.
The proposed system supports various functions such as real-time communication via text, audio, camera display between an instructor and students, desktop share, streaming multimedia, e-board and sending files. In addition, it supports various types of teaching such as lecture, discussion and examination; lecture planning to set proper teaching methods, time and teaching steps; teaching evaluation to improve teaching methods through impersonal evaluation by students. It also supports group competition, discussion and presentation, foreign language audio-visual lectures and investigation of understanding through exams at any time.
The system can put the whole lecture process on IT footing and improve the density and effectiveness of teaching by employing superior teaching methods. Also, it can implement feedback coupling to develop new teaching methods through impersonal evaluation by students.
...
Jo May 8, 2023
Pak Yong Ho, a researcher at the Nano Physics Engineering Institute, by using a polymer jet fluid model by CFD, has calculated the velocity field distribution in it to determine a uniform velocity profile and determined a new curved profile of the collector to obtain uniform fiber in an arched multi-nozzle electrospinning device.
Electrospinning is a method of producing micro fibres by injecting polymer solutions in electrostatic fields. Microfibers obtained by electrospinning have widely been applied in various fields, due to their superior properties such as very small diameter, high porosity, large specific surface area, etc.
Recently, highly productive electrospinning methods such as multi-nozzle electrospinning and nozzle-free electrospinning have been proposed. Multi-nozzle electrospinning is a method of overlapping many nozzles, so it is difficult to realize stable and continuous spinning as nonuniform distribution of electric fields at the nozzle tip creates corona discharge by strong electrical interaction between the nozzles.
Based on the calculation of the flow rate in angular jet flow through a CFD simulation of the jet flow in an electrostatic field, he determined the contour shape of the collector plate obtained by the uniform velocity plane. Then, he drew the curve equation of the curved collector which can obtain uniform diameter electrospun fiber in the multi-nozzle electrospinning system where an arched multi-nozzle and a curved collector are combined. After that, he found the curve equation of the curved collector to obtain uniform electrospun nanofiber with the diameter of 131.3nm, which is suitable for preparing a nanofiber ionexchange membrane for electrodialysis.
The curve equation of the collector profile for obtaining the electrospun nanofiber (131.3nm in diameter) in an arched multi-nozzle electrospining device is y=-2-12x3+0.002x2-2-8x-91.991.
It means that a new methodology to obtain uniform electrospun fibers with arbitrary diameters in a multi-nozzle electrospinning device without additional means was developed.
...
Jo May 7, 2023
“Rimwonsipryukji” compiled by a realist scholar So Yu Gu (1764―1845) in 1825, is a national classic where documentary records concerning economy and culture are arranged in categories.
Rimwonsipryukji, which is left incomplete, is a huge work, running to 113 volumes and 62 books. This enables us to guess what an enormous book he mapped out.
Divided into 16 parts, Rimwonsipryukji contains valuable information extracted from as many as 500-odd kinds of domestic and foreign records that was considered indispensable for developing the national economy and daily life. All the information is organized in categories and followed by the origins of the data and the author’s opinion of each item.
The front parts Ponriji and Kwangyuji are about agriculture. Here, general knowledge of agriculture and methods of cultivating and processing 33 kinds of vegetables and over 20 kinds of medicinal herbs are introduced. The author wrote that success or failure of agriculture depends on the skills and efforts of humans, not on natural conditions.
The horticultural parts Yewonji and Manhakji deal with methods of growing more than 50 kinds of flowers, over 30 kinds of ornamental grasses, 30 kinds of fruit trees, several kinds of trees, tea plants, tobacco plants, etc. and even those of changing the colours of flowers artificially.
Poyangji and Injeji give a detailed description of rules of diet for good health and longevity, exercise, massage, taking medicine, taking care of the elderly and children, and other things concerned with branches of medicine like gynaecology, paediatrics, surgery, etc.
Rimwonsipryukji serves as one of the invaluable national classics since it not only reflects the author’s aspiration to make a positive contribution to the development of the national economy and culture but also contains copious amount of all-round knowledge about the socio-economic situations, medicine, food culture, life style, etc. in the latter half of the feudal Joson dynasty.
Ri Won Chol, researcher at the Academy of Social Sciences
...
Jo May 5, 2023
Ro Myong Gum, a researcher at the Nano Physics Engineering Institute, has investigated the effects of laser power on the reduction of graphene oxide by 355nm UV impulse laser.
Graphene oxide, which is chemically exfoliated from graphite, a precursor of graphene, is a suitable material for producing graphene in large quantities. However, reduction is necessary because graphene oxide is an insulator.
In the past, a chemical method, heating treatment, microwave and plasma, etc. were applied to the reduction of graphene oxide, but nowadays graphene oxide reduction by laser is under study.
She performed some experiments on the thermodynamic change of a graphene oxide film when graphene oxide is irradiated by 355nm UV impulse laser, and confirmed the impact factors of laser on the reduction.
As compared with conventional reduction methods, the proposed method is simple in process and enables reduction and mask at the same time, so it will prove the most suitable for manufacturing micro-electronic devices.
...
© 2021 Kim Chaek University of Technology