Heedong Lee

Dr. Heedong Lee

orcid

Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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4 November 2020 in Polymers
Verified
Journal Article
Open access
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YPYoung Ki Park
Young Ki Park
HOHyun Ju Oh
Hyun Ju Oh
JBJong Hyuk Bae
Jong Hyuk Bae
JLJee Young Lim
Jee Young Lim
HLHeedong Lee
Heedong Lee
WLWoosung Lee
Woosung Lee
For the immediate detection of strong gaseous alkalis and acids, colorimetric textile sensors based on halochromic dyes are highly valuable for monitoring gas leakages. To date, colorimetric textile sensors for dual-gas detection have usually been fabricated by electrospinning methods. Although nanofibrous sensors have excellent pH sensitivity, they are difficult to use commercially because of their low durability, low productivity, and high production costs. In this study, we introduce novel textile sensors with high pH sensitivity and durability via a facile and low-cost screen-printing method. To fabricate these textiles sensors, Dye 3 and RhYK dyes were both incorporated into a polyester fabric. The fabricated sensors exhibited high detection rates (<10 s) and distinctive color changes under alkaline or acidic conditions, even at low gas concentrations. Furthermore, the fabricated sensors showed an outstanding durability and reversibility after washing and drying and were confirmed to contain limited amounts of hazardous materials. Thus, our results show that the fabricated textile sensors could be used in safety apparel that changes its color in the presence of harmful gases.

15 February 2021 in Polymers
Verified
Journal Article
Open access
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IJIn Su Jin
In Su Jin
HLHeedong Lee
Heedong Lee
SHSeok Il Hong
Seok Il Hong
WLWoosung Lee
Woosung Lee
JJJae Woong Jung
Jae Woong Jung
Typical polyol-based synthesis of silver nanowire employs insulating polymer as a surfactant for the silver nanowire growth, which limits direct contact between each nanowire and thus its optoelectronic properties. We herein demonstrate that a simple solvent treatment effectively removes the insulating polymer around Ag NWs, leading to significantly decreased sheet resistance (~12 Ω/sq) with an increased transmittance (81% @ T550), as compared to other post-treatments. We successfully demonstrate the transparent film heaters using the solvent-treated Ag NWs network, which rapidly exhibited 150 °C under a bias of 5 V. Flexible film heaters on plastic substrate is also demonstrated, suggesting a great potential of the solvent treatment process of Ag NWs for flexible transparent electrode and film heater applications.

2 April 2024 in Fashion and Textiles
Verified
Journal Article
Open access
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MKMinsuk Kim
Minsuk Kim
JSJae Yun Shim
Jae Yun Shim
SLSeungju Lim
Seungju Lim
HLHeedong Lee
Heedong Lee
SKSoon Chul Kwon
Soon Chul Kwon
SRSu Jin Ryu
Su Jin Ryu
Owing to global warming and pollution concerns, reducing the environmental footprint of the textile and fashion industry has received considerable attention. Within this industry, the dyeing and finishing processes contribute significantly to greenhouse gas emissions and water pollution. This study introduces an innovative approach to address these challenges by leveraging digital twin technology to optimize the textile dyeing process. A smart analysis module was developed to continuously monitor and analyze the dyeing parameters in real time to implement control actions to automatically reduce the process duration. Integrated with this module, a digital twin of the dyeing machine enabled the real-time monitoring of energy consumption and process parameters. A case study comparing the traditional dyeing process with the optimized process was conducted. The results showed that dyeing time was reduced by ~ 17.5% without compromising dyeing quality. Energy consumption and greenhouse gas emissions were also reduced by ~ 12.1% when using the optimized process. This study offers a practical and sustainable option for textile dyeing, particularly for small and medium-sized enterprises.

23 April 2022 in Energies
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Journal Article
Open access
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YKYurim Kim
Yurim Kim
JLJonghun Lim
Jonghun Lim
JSJaeyun Shim
Jaeyun Shim
SHSeokil Hong
Seokil Hong
HLHeedong Lee
Heedong Lee
HCHyungtae Cho
Hyungtae Cho
Reactive dyeing is primarily used in the textile industry to achieve a high level of productivity for high-quality products. This method requires heating a large amount of freshwater for dyeing and cooling for the biological treatment of discharged wastewater. If the heat of the wastewater discharged from the textile industry is recovered, energy used for heating freshwater and cooling wastewater can be significantly reduced. However, the energy efficiency of this industry remains low, owing to the limited use of waste heat. Hence, this study suggested a cost-optimal heat exchanger network (HEN) in a heat pump-assisted textile industry wastewater heat recovery system with maximizing energy efficiency simultaneously. A novel two-step approach was suggested to develop the optimal HEN in heat pump-assisted textile industry wastewater heat recovery system. In the first step, the system was designed to integrate the heat exchanger and heat pump to recover waste heat effectively. In the second step, the HEN in the newly developed system was retrofitted using super-targeted pinch analysis to minimize cost and maximize energy efficiency simultaneously. As a result, the proposed wastewater heat recovery system reduced the total annualized cost by up to 43.07% as compared to the conventional textile industry lacking a wastewater heat recovery system. These findings may facilitate economic and environmental improvements in the textile industry.

30 September 2023 in Polymers
Verified
Journal Article
Open access
PDF file
SRSu Jin Ryu
Su Jin Ryu
DKDoyeon Kim
Doyeon Kim
HLHyewon Lee
Hyewon Lee
YKYoonjin Kim
Yoonjin Kim
YLYoungbok Lee
Youngbok Lee
HLHoik Lee
Hoik Lee
The typical filters that protect us from harmful components, such as toxic gases and particulate matter (PM), are made from petroleum-based materials, which need to be replaced with other environmentally friendly materials. Herein, we demonstrate a route to fabricate biodegradable and dual-functional filtration membranes that effectively remove PM and toxic gases. The membrane was integrated using two layers: (i) cellulose-based nanofibers for PM filtration and (ii) metal–organic framework (MOF)-coated cotton fabric for removal of toxic gases. Zeolitic imidazolate framework (ZIF-8) was grown from the surface of the cotton fabric by the treatment of cotton fabric with an organic precursor solution and subsequent immersion in an inorganic precursor solution. Cellulose acetate nanofibers (NFs) were deposited on the MOF-coated cotton fabric via electrospinning. At the optimal thickness of the NF layer, the quality factor of 18.8 × 10−2 Pa−1 was achieved with a filtration efficiency of 93.1%, air permeability of 19.0 cm3/cm2/s, and pressure drop of 14.2 Pa. The membrane exhibits outstanding gas adsorption efficiencies (>99%) for H2S, formaldehyde, and NH3. The resulting membrane was highly biodegradable, with a weight loss of 62.5% after 45 days under standard test conditions. The proposed strategy should provide highly sustainable material platforms for practical multifunctional membranes in personal protective equipment.

7 August 2023 in JMIR Formative Research
Verified
Journal Article
Open access
HKHyunsoo Kim
Hyunsoo Kim
SJSeong Jin Jang
Seong Jin Jang
HLHeedong Lee
Heedong Lee
JKJae Hoon Ko
Jae Hoon Ko
JLJee Young Lim
Jee Young Lim
Background: The rise in single-person households has resulted in social problems like loneliness and isolation, commonly known as “death by loneliness.” Various factors contribute to this increase, including a desire for independent living and communication challenges within families due to societal changes. Older individuals living alone are particularly susceptible to loneliness and isolation due to limited family communication and a lack of social activities. Addressing these issues is crucial, and proactive solutions are needed. It is important to explore diverse measures to tackle the challenges of single-person households and prevent deaths due to loneliness in our society. Objective: Non–face-to-face health care service systems have gained widespread interest owing to the rapid development of smart home technology. Particularly, a health monitoring system must be developed to manage patients’ health status and send alerts for dangerous situations based on their activity. Therefore, in this study, we present a novel health monitoring system based on the auto-mapping method, which uses real-time position sensing mats. Methods: The smart floor mats are operated as piezo-resistive devices, which are composed of a carbon nanotube–based conductive textile, electrodes, main processor circuit, and a mat. The developed smart floor system acquires real-time position information using a multiconnection method between the modules based on the auto-mapping algorithm, which automatically creates a spatial map. The auto-mapping algorithm allows the user to freely set various activity areas through floor mapping. Then, the monitoring system was evaluated in a room with an area of 41.3 m2, which is embedded with the manufactured floor mats and monitoring application. Results: This monitoring system automatically acquires information on the total number, location, and direction of the mats and creates a spatial map. The position sensing mats can be easily configured with a simple structure by using a carbon nanotube–based piezo-resistive textile. The mats detect the activity in real time and record location information since they are connected through auto-mapping technology. Conclusions: This system allows for the analysis of patients’ behavior patterns and the management of health care on the web by providing important basic information for activity patterns in the monitoring system. The proposed smart floor system can serve as the foundation for smart home applications in the future, which include health care, intelligent automation, and home security, owing to its advantages of low cost, large area, and high reliability.