Jo Jan 19, 2023
Ju Yong Chol, a section head at the Nano Physics Engineering Institute, and his research team members built an assembly-line microwave dryer for drying pills at pharmaceutical plants.
Microwave heating, compared to other ways of heating, is exellent in thermal efficiency and heating rate since it is focused on target objects only. It provides uniform thermal spread on the outside and inside of objects. Easy adjustment of microwave output leads to easy adjustment of heating rate. The dryer is simple in its structure and easy to operate. Microwave drying is being widely introduced in several fields like pharmaceutical industry and foodstuff industry thanks to its high production efficiency and high quality of products.
The assembly-line microwave dryer consists of a microwave generation sector, a control sector, a conveyor sector, a ventilation sector, a microwave leak checking sector, etc.
In the microwave generation sector are six magnetrons with 700W output. 2.8kW microwave is generated in real time by four of them in operation in turns and two cooling down.
In the control sector, there are electric circuit blocks to turn 4 magnetrons on and 2 magnetrons off. It controls the transmission speed of the conveyor.
In the conveyor sector, the belt on the bottom of the drying cavity is moved by the reduction motor with 90W output and 1 450r/min. The transmission velocity is 0~70cm/min.
In the ventilation sector, a 300L/min exhauster between the two drying cavities expels wet steam from the drying cavity generated during drying processes at the deflation speed of 3m/s.
In the microwave leak checking sector, the reflection-type microwave leak checker reflects the microwave propagated through the inlet and outlet of the drying cavity back into the drying cavity, which checks microwave leak and meets the permitted limit on the international standard.
The dryer proved to be effective in reducing the humidity of pills by 5% at 40kg per hour. Hygienic safety of products is ensured and production cost is reduced to half.
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Jo Jan 18, 2023
Pyon Chol Ung, a researcher at the Faculty of Communications, has developed and introduced a directive communication system in pits using electric-car lines.
The system enables route directive communication with moving electric cars through electric car lines in pits.
The pit directive transceiver consists of a digital signal processing unit, an interface with electric car lines, an audio signal interface and transmission and reception units.
The digital signal processing unit is responsible for carrying various commands and status signals between all peripheral devices, compressing and coding the audio data from the audio signal interface, digitally phase-modulating the audio data in succession, digitally demodulating the high-frequency signals from the interface with electric car lines and decoding the compressed audio data.
The interface with electric car lines plays a role of blocking DC and AC noises from electric car lines and passing only necessary high-frequency signals.
The audio-signal interface converts the analog audio signals generated from the microphone into digital signals and transfers them to the digital signal processing unit. It also converts the digital audio data generated from the digital signal processing unit into analog signals and outputs them through the speaker.
The transmission unit is made up of a backup amplifier, an output terminal and a coupling transformer. It amplifies digitally modulated high frequency signals to a certain degree. As the transceiver operates on a battery, it is important to enhance the efficiency of the output terminal. Therefore, a D-grade symmetrical amplifier with a field effect output transistor was chosen for the output amplifying unit.
The reception unit is comprised of a limiter, a band-pass filter and a high frequency amplifier. It amplifies the trivial signals coming from electric car lines with noise and removes unnecessary noises.
As the system does not need additional wired or wireless communication devices such as communication cable or radio repeaters but only existing electric car lines, it saves not only a huge amount of money for communication equipment but also a lot of labour necessary for its maintenance, repair and operation.
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Jo Jan 17, 2023
A research team led by Pak Chan Il, a section head at the IT Institute, has developed a land and environment information system “Mannyondaegye”, based on GIS.
The system offers inspection, measuring, search, analysis, statistic research and editing of a wide range of information in the field of land and environment such as land, forests, roads, rivers and streams, and national boundaries on PCs.
Several technologies and functions are realized in the system: 3D visualization of raster data, stratification and segmentation for visualization of big vector data in the land and environment sector, measurement of distances, areas, etc. on the map, spatial and non-spatial searches in various modes, addition and editing of spatial objects and subjects, and data import and export.
It guarantees scientific accuracy in GIS-based businesses for management of land and environment resources and serves as an integrated GIS, which means the possibility of an effective use in various sectors of the national economy.
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Jo Jan 15, 2023
Ri Jong Ju, a researcher at the Faculty of Communications, has invented a color identification method for HDTV broadcasting video monitors.
Nowadays, there has been a continuous increase in the demand for the quality of TV broadcasting and it includes color as well as video resolution. In order to represent the correct colour, dedicated video monitors supervise colors strictly when TV programs and TV sets are made. However, reference whites in each video monitor which are used as reference are a bit different so it is necessary to calibrate the colours of video monitors.
Colour identification is for adjusting the colour presentation characters of video monitors so that they show exactly the same colours for the same video.
Some equipment and software are used for colour calibration and every video monitor has its own calibration equipment.
The proposed method is useful for video monitors without their own calibration equipment. To display the same colours, the values of three primary colours should be in the same tolerance range. The method employs a colour analyzer and a spectrum analyzer.
First, both the colour analyzer and the spectrum analyzer measure the same video to set a reference value in the colour analyzer. Next, a measurement value and a target value of reference white in the colour calibration program are input before calculating adjustment values. At that time, various colour conversions and colour difference calculation algorithms are used in the program. Then, measurement mode is switched to analysis mode to adjust the colours of monitors to the value. When the target white colour reaches the same value, the monitors display the same colours.
The method was also applied to normal LCD TVs to use them as HDTV broadcasting video monitors. It produced the same effect.
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Jo Jan 13, 2023
A research team led by Kim Kang Sop, an institute head at the Faculty of Earth Science and Technology, has succeeded in his study on delineation of deep anthracite seams with random forest predictor that learnt multi-geophysical and drill-hole datasets.
Anthracite formed in the upper paleozoic era is a fundamental resource of fuel and raw material in our country. Thus, it is of great significance to improve the accuracy of a deep survey based on drillholes and geophysical data in the vicinity of existing anthracite-mines.
Several geophysical methods are available due to its low-resistivity, density, magnetic susceptibility, and high spontaneous-potential (SP). However, these methods have different limitations of penetration depth and resolution, and are critically affected by noises from powerlines, terrain, and geological complexity.
They conducted multiple-geophysical fieldworks at an anthracite mine, involving transient electromagnetic (TEM), SP, gravity, and magnetic prospectings to construct the database of existing drillholes. The study area in difficult terrain had four anthracite seams under the rough surface to the depth of about 800m. They showed irregular behavoir due to structural activities in the Mesozoic era. Fortunately, many holes which had already been drilled in the anthracite seams, could provide useful information to interpret the given geophysical datasets.
The problem was to build an appropriate strategy to constrain deep anthracite seams and evaluate the reserve by inverting multi-geophysical datasets along with the existing drill-hole database, throughout the study area including the parts with no drillholes.
They had some problems. First, drillhole data may be converted as a priori information for inverting geophysical data. However, seperated inversion may yield subsurface images of physical property with a remarkable difference from the real geology. Next, joint-inversion of multi-geophysical datasets may be another altenative. But this manner requires an elaborate code writing to incorporate realistic terrain and drillhole information.
Thus, they chose the random forest (RF) predictor which is recognized to be the most powerful for solving multiple-classfication problems. The RF is a prediction (classification) algorithm that has a classification tree as the elementary learner and is incorporated with the ensemble aggregation method. It shows higher generalization performance than other machine-learning algorithms.
On the basis of such preparations, they wrote an RF predictor. The inputs of RF predictor involved TEM, SP, gravity, and magnetic datasets and the outputs were designed to yield the upper depth and thickness of deep anthracite seams. The teaching signals were supplied based on the elevation and thickness of seams known from drillholes. The RF predictor, after learning the given teacher signals successfuly, yielded an objective evaluation of the study area including undrilled parts, and enabled them to predict new anthracite-rich regions and evaluate the reserve.
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Jo Jan 9, 2023
A research team led by Hong Sung Chol, a researcher at the Faculty of Heat Engineering, has developed and introduced various types of energy conservational boilers.
Energy conservational unpowered boiler with a package of fire-tube heaters combined with fin array in box type
The boiler satisfies heat requirements needed for production and heating with a small amount of fuel. It costs little to manufacture and install. It is simple in its composition and principle and easy to reset the load. It has the highest heat output for furnaces of the same volume. In addition, for the same heat output, it consumes a lot less fuel and material than other fire-tube heaters. Especially, it is very convenient to introduce them as they are standardized in 10 heat outputs with seven optimized indicators to ensure the scientific accuracy, economy and promptness of introduction in consideration of its various types and conditions of installation. The boiler makes the most use of the produced heat by preheating water from the heat included in waste ash, by using the flue gas from heating and by keeping boiler walls warm. Compared with conventional boilers of the same furnace volume, it provides three times as much heat output (η=88~93%), consumes less fuel by 1/4 [fuel consumption of 162kW hot water heater: B=100~110kg/d(Qar=20MJ/㎏)] and material by over 1/2, and reduces the number of boilers for a unit heating area.
Energy conservational steam bath boiler
It is made up of the cylindrical body that produces both heat and hot water at the same time by recycling wasted heat, a water heater, a feed water inlet, a hot water outlet, a fuel inlet, a fire-grate and a chimney. The annular upper and lower heaters inside the body and the outer collecting heater and economizer outside the body maintain the temperature of a sauna at over 75~85℃ and produce hot water of 40~50℃ at 2~2.5t/h. (fuel consumption B=40kg/d)
Boiler for hot water tank
In the boiler is a hot water heater in the shape of a nest which is combined with a plate and a water pipe. The hot water system consumes no electricity and is operated by natural ventilation and cycle. It can produce hot water of 65~75℃ at 40~45t/d. (fuel consumption B=60kg/d)
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