• Membrane Journal
• /
• v.23 no.1
• /
• pp.24-44
• /
• 2013

The MBR technology has evolved rapidly over the past two decades with significant gains in performance and reliability, and reductions in costs. Membrane bioreactors (MBR) technology is widely recognised as offering a key option for enhanced wastewater treatment or reuse. The objective of this paper is then to critically review the remarkable achievement on the research and commercial applications of membrane bioreactor (MBR) technology and to present current and potential MBR markets on a global scope. This brief review of the technology incorporates five key aspects : 1) evolution of MBR practice, 2) the commercial technologies of MBRs, 3) the largest MBR installations globally (e.g. > $10,000m^3/day$), 4) MBR market growth, and 5) directions for future research. Finally, the development directions of economical, environmental and technical aspects in MBRs; 1) investment costs; 2) effluent water quality; 3) membrane materials and modules; 4) MBR equipment and treatment process; 5) operating costs (higher energy & chemical consumption); and 6) sustainability such as anaerobic MBRs in the coming years were addressed.

• Journal of Surface Science and Engineering
• /
• v.32 no.3
• /
• pp.239-243
• /
• 1999

At Present, 200mm wafer technology is being applied for commercial fabrications of 64, 128, and 256 M DRAM devices, and 300mm technology will be evolved for 1G DRAM devices in the early 21th century, recognizing limitations of several process technologies. In particular recognition has been realized in harmful effects of surface contamination of trace metals introduced during devicing processes. Such a guide line for surface metal contamination has been proposed as 1E9 and 1E10 atoms/$\textrm{cm}^2$ of individual metal contamination for wafering and devicing of 1G DRAM, respectively, and so its measurement limit should be at least 1E8 atoms/$\textrm{cm}^2$. The detection limit of present measurement systems is 2E9 atoms/$\textrm{cm}^2$ obtainable with TRXFA(Total Reflection X-Ray Fluorescence Analysis). TRXFA is nondestructive and the simplest in terms of operation, and it maps the whole wafer surfaces but needs detection improvement. X-Ray intensity produced with synchrotron accelerator is much higher than that of conventional X-ray sources by order of 4-5 magnitudes. Hence theoretically its reactivity with silicon surfaces is expected to be much higher than the conventional one, realizing improvement of detection limit. X-ray produced with synchrotron accelerator is illuminated at a very low angle with silicon wafer surfaces such as 0.1 degree and reflects totally. Hence informations only from surface can be collected and utilized without overlapping with bulk informations. This study shows the total reflection phenomenon and quantitative improvement of detection limit for metallic contamination. It is confirmed that synchrotron X-ray can be a very promising alternative for realizing improvement of detection limit for the next generation devices.

• Journal of the Korea Society of Computer and Information
• /
• v.28 no.8
• /
• pp.95-101
• /
• 2023

Colmap is one of the innovative artificial intelligence technologies, highly effective as a tool in 3D reconstruction tasks. Moreover, it excels at constructing intricate 3D models by utilizing images and corresponding metadata. Colmap generates 3D models by merging 2D images, camera position data, depth information, and so on. Through this, it achieves detailed and precise 3D reconstructions, inclusive of objects from the real world. Additionally, Colmap provides rapid processing by leveraging GPUs, allowing for efficient operation even within large data sets. In this paper, we have presented a method of collecting 2D images of traditional Korean towers and reconstructing them into 3D models using Colmap. This study applied this technology in the restoration process of traditional stone towers in South Korea. As a result, we confirmed the potential applicability of Colmap in the field of cultural heritage restoration.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.36 no.2
• /
• pp.143-150
• /
• 2023

Underwater wireless communication is a challenging issue for realizing the smart aqua-farm and various marine activities for exploring the ocean and environmental monitoring. In comparison to acoustic and radio frequency technologies, the visible light communication is the most promising method to transmit data with a higher speed in complex underwater environments. To send data at a speedier rate, high-performance photodetectors are essentially required to receive blue and/or cyan-blue light that are transmitted from the light sources in a light-fidelity (Li-Fi) system. Here, we fabricated high-performance organic phototransistors (OPTs) based on P-type donor polymer (PTO2) and N-type acceptor small molecule (IT-4F) blend semiconductors. Bulk-heterojunction (BHJ) PTO2:IT-4F photo-active layer has a broad absorption spectrum in the range of 450~550 nm wavelength. Solution-processed OPTs showed a high photo-responsivity >1,000 mA/W, a large photo-sensitivity >10³, a fast response time, and reproducible light-On/Off switching characteristics even under a weak incident light. BHJ organic semiconductors absorbed photons and generated excitons, and efficiently dissociated to electron and hole carriers at the donor-acceptor interface. Printed and flexible OPTs can be widely used as Li-Fi receivers and image sensors for underwater communication and underwater internet of things (UIoTs).

• Journal of the Korean Applied Science and Technology
• /
• v.32 no.2
• /
• pp.348-361
• /
• 2015

To reduce the effects of greenhouse gas (GHG) emissions, the government has announced the special platform of technologies as parts of an effort to minimize global climate change, and the government distributed biodiesel since 2006 as the further efforts. Although there are some debates about some quality specifications and unbalanced of source (44% from palm oil), more than 400kton/year of biodiesel was produced in 2013. Moreover the amounts will be increased when the RFS is activated. To solve the unbalanced situation and to achieve the diversity of feeds, it is essential that many researches should be considered. Especially, free and bond glycerines are one of the important properties seriously affected to the combustion system in vehicle & cold properties. Previous method (KS M 2412) couldn't cover the biodiesel derived from lauric oil($C_{12:0}$) such as PKO (Palm Kernel Oil), Coconut oil because those compositions are lighter than other conventional biodiesel sources. In this study, we review the existed method and figure out the factors should improve to analysis the glycerine from PKO and Coconut oil biodiesel. Modifying the analysis conditions to enhance the resolution and change the internal standards to avoid the overlapped- peaks between Capric acid ME ($C_{10:0}$) and standard#1(1,2,4-butantriol). From this revised method, we could solve the restrictions of previous methods. And check the possibility of new method to analyze the glycerine in biodiesel regardless of sources.

• Korean Journal of Remote Sensing
• /
• v.31 no.3
• /
• pp.215-226
• /
• 2015

Normally, aero photography using UAV uses about 430 MHz bandwidth radio frequency (RF) modem and navigates and remotely controls through the connection between UAV and ground control system. When using the exhausting method, it has communication range of 1-2 km with frequent cross line and since wireless communication sends information using radio wave as a carrier, it has 10 mW of signal strength limitation which gave restraints on life my distance communication. The purpose of research is to use communication technologies such as long-term evolution (LTE) of smart camera, Bluetooth, Wi-Fi and other communication modules and cameras that can transfer data to design and develop automatic shooting system that acquires images to UAV at the necessary locations. We conclude that the android based UAV filming and communication module system can not only film images with just one smart camera but also connects UAV system and ground control system together and also able to obtain real-time 3D location information and 3D position information using UAV system, GPS, a gyroscope, an accelerometer, and magnetic measuring sensor which will allow us to use real-time position of the UAV and correction work through aerial triangulation.

• Korean Chemical Engineering Research
• /
• v.57 no.4
• /
• pp.539-546
• /
• 2019

Global warming has mentioned as one of the international problems and these researches have conducted. Carbon Capture, Utilization and Storage (CCUS) technology has improved due to increasing importance of reducing emission of carbon dioxide. Among of various CCUS technologies, mineral carbonation can converted $CO_2$ into high-cost materials with low energy. Existing researches has been used ions extracted solid wastes for mineral carbonation but the procedure is complicated. However, the procedure using seawater is simple because it contained high concentration of metal cation. This research is a basic study using seawater-based wastewater for mineral carbonation. 3 M Monoethanolamine (MEA) was used as $CO_2$ absorbent. Making various concentrations of seawater solution, simulated seawater powder was used. Precipitated metal carbonate salts were produced by mixing seawater solutions and $rich-CO_2$ absorbent solution. They were analyzed by X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Thermogravimetric Analysis (TGA) and studied characteristic of producing precipitated metal carbonate and possibility of reusing absorbent.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.4
• /
• pp.63-68
• /
• 2018

The establishment of Ground Control Points (GCPs) in UAV-Photogrammetry is a working process that requires the most time and expenditure. Recently, the rapid developments of navigation sensors and communication technologies have enabled Unmanned Aerial Vehicles (UAVs) to conduct photogrammetric mapping without using GCP because of the availability of new methods such as RTK (Real Time Kinematic) and PPK (Post Processed Kinematic) technology. In this study, an experiment was conducted to evaluate the potential of RTK-UAV mapping with no GCPs compared to that of non RTK-UAV mapping. The positioning accuracy results produced by images obtained simultaneously from the two different types of UAVs were compared and analyzed. One was a RTK-UAV without GCPs and the other was a non RTK-UAV with different numbers of GCPs. The images were taken with a Canon IXUS 127 camera (focal length 4.3mm, pixel size $1.3{\mu}m$) at a flying height of approximately 160m, corresponding to a nominal GSD of approximately 4.7cm. As a result, the RMSE (planimetric/vertical) of positional accuracy according to the number of GCPs by the non-RTK method was 4.8cm/8.2cm with 5 GCPs, 5.4cm/10.3cm with 4 GCPs, and 6.2cm/12.0cm with 3 GCPs. In the case of non RTK-UAV photogrammetry with no GCP, the positioning accuracy was decreased greatly to approximately 112.9 cm and 204.6 cm in the horizontal and vertical coordinates, respectively. On the other hand, in the case of the RTK method with no ground control point, the errors in the planimetric and vertical position coordinates were reduced remarkably to 13.1cm and 15.7cm, respectively, compared to the non-RTK method. Overall, UAV photogrammetry supported by RTK-GPS technology, enabling precise positioning without a control point, is expected to be useful in the field of spatial information in the future.

• Journal of Embryo Transfer
• /
• v.32 no.3
• /
• pp.131-138
• /
• 2017

In most mammals, metaphase II (MII) oocytes having high maturation promoting factor (MPF) activity have been considered as good oocytes and then used for assisted reproductive technologies including somatic cell nuclear transfer (SCNT). Caffeine increases MPF activity in mammalian oocytes by inhibiting p34cdc2 phosphorylation. The objective of this study was to investigate the effects of caffeine treatment during in vitro maturation (IVM) on oocyte maturation and embryonic development after SCNT in pigs. To this end, morphologically good (MGCOCs) and poor oocytes (MPCOCs) based on the thickness of cumulus cell layer were untreated or treated with 2.5 mM caffeine during 22-42, 34-42, or 38-42 h of IVM according to the experimental design. Caffeine treatment for 20 h during 22-42 h of IVM significantly inhibited nuclear maturation compared to no treatment. Blastocyst formation of SCNT embryos was not influenced by the caffeine treatment during 38-42 h of IVM in MGCOCs (41.1-42.1%) but was significantly improved in MPCOCs compared to no treatment (43.4 vs. 30.1%, P<0.05). No significant effects of caffeine treatment was observed in embryo cleavage (78.7-88.0%) and mean cell number in blastocyst (38.7-43.5 cells). The MPF activity of MII oocytes in terms of p34cdc2 kinase activity was not influenced by the caffeine treatment in MGCOCs (160.4 vs. 194.3 pg/ml) but significantly increased in MPCOCs (133.9 vs. 204.8 pg/ml). Our results demonstrate that caffeine treatment during 38-42 h of IVM improves developmental competence of SCNT embryos derived from MPCOCs by influencing cytoplasmic maturation including increased MPF activity in IVM oocytes in pigs.

• Journal of Korea Soil Environment Society
• /
• v.2 no.3
• /
• pp.3-21
• /
• 1997

The remediation of contamiated sites using currently available remediation technologies requires long term treatment and huge costs, and it is uncertain to achieve the remediation goal to drop contamination level to either back-ground or health-based standards by using such technologies. Intrinsic remediation technology is the remediation technology that relies on the mechanisms of natural attenuation for the containment and elimination of contaminants in subsurface environments. Initial costs for the intrinsic remediation may be higher than conventional treatment technologies because the most comprehensive site assessment for intrinsic remediation is required. Total remediation cost, however may be the lowest among the presently employed technologies. The applicability of intrinsic remediation in the contaminated sites should be theroughly investigated to achieve the remedial goal of the technology. This paper provides the frame of the extended site assessment procedure based on knowledge of biodegradability to evaluate the applicability of intrinsic remediation. This site assessment procedure is composed of 5 steps such as preliminary site screening, assessment of the current knowledge of biodegradability, selecting the appropriate approach, analyzing the contaminant fate and transport and planning the monitoring schedule. In the step 1, followings are to be decided 1) whether to go on the the detailed assessment or not based on the rules of thumb concerning the biodegradability of organic compounds, 2) which protocol document is selected to follow for detailed site assessment according to the site characteristics, contaminants and the relative distance between the contamination and potential receptors. In the step 2, the database for biodegradability are searched and evaluated. In the step 3, the appropriate biodegradability pathways for the contaminated site is selected. In the step 4, the fate and transport of the contaminants at the site are analyzed through modeling. In the step 5, the monitoring schedule is planned according to the result of the modeling. Through this procedure, users may able to have the rational and systematic informations for the application of intrinsic remediation. Also the collected data and informations can be used as the basic to re-select the other remediation technology if it reaches a conclusion not to applicate intrinsic remediation technology at the site from the site assessment procedure.