材料の高機能化に関する研究。具体的には，二次電池材料，新しい機構の燃料電池，あるいはエネルギー変換系，更には固体系水素貯蔵材料など，広い意味でのエネルギー貯蔵及びエネルギー変換材料の反応機構解明と高性能化に関する研究，廃棄物系アンモニアの回収と有効利用に関する研究。
Research and development of energy conversion materials which are in particular related to: Secondary battery materials; Fuel cell with non-conventional mechanisms, energy conversion systems, and/or solid state hydrogen storage materials; Energy recovery from waste and biomass.

Keywords: Materials for secondary battery, Mechanical Milling, Ball-Milling, Hydrogen Storage Material, Hydrie

1. Thermal desorption processes of H2 and CH4 from Li2ZrO3 and Li4SiO4 materials absorbed H2O and CO2 in air at room temperature, INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, 48(24), 8830-8836, 20230319
2. Ion diffusion, and hysteresis of magnesium hydride conversion electrode materials, JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY, 155, 47-53, 20230820
3. ★, Metal hydride-based materials towards high performance negative electrodes for all-solid-state lithium-ion batteries, CHEMICAL COMMUNICATIONS, 51(48), 9773-9776, 20150515

超臨界水によるバイオマスからの水素の製造，超臨界水中における伝熱と化学反応の制御，バイオマスの水熱前処理，水熱炭化，ケミカルヒートポンプ，カーボンナノチューブの応用研究。
Production of hydrogen from biomass using supercritical water; Heat transfer and chemical reactions in supercritical water; Hydrothermal pretreatment of biomass; Hydrothermal carbonization; Chemical heat pump; Application research of carbon nanotube.

Keywords: Biomass Organic Waste, Supercritical Fluid

1. Gasification characteristics of carbon nanotube in supercritical water, JOURNAL OF SUPERCRITICAL FLUIDS, 182, 202203
2. Slow Pyrolysis of Ulva lactuca (Chlorophyta) for Sustainable Production of Bio-Oil and Biochar, SUSTAINABILITY, 14(6), 202203
3. The Potential of Sustainable Biogas Production from Macroalgae in Indonesia, IOP Conf. Ser.: Earth Environ. Sci., 1038, #012020, 202110

開発途上国における持続可能な開発の実現を目指した建築・都市環境学
Building and urban environmental science for achieving sustainable development in developing world

Keywords: Tropics|Urban heat island, Natural ventilation, Sustainable development, Energy-saving, Developing world, Tropics, Passive cooling, Life cycle assessment, Wind flow, Sustainable building assessment tool

1. Factors affecting multiple chemical sensitivity (MCS) in newly constructed apartments of Indonesia, Building and Environment, 241(110482), 20230801
2. Analysis of typical layout of apartment buildings in Indonesia, Buildings, 13(6)(1387), 20230526
3. ★, The effects of night ventilation technique on indoor thermal environment for residential buildings in hot-humid climate of Malaysia, ENERGY AND BUILDINGS, 41(8), 829-839, 200908

再生可能エネルギー資源(風力・太陽光・海洋エネルギー)評価及び管理，沿岸災害および防災・減災のための数値モデル，気候変動による再生可能エネルギー資源・災害変化予測
Renewable energy resource (wind, solar and ocean energy) evaluation and management, Numerical models for coastal hazards, and disaster prevention and mitigation, Evaluation of climate changes impacts on natural hazards and renewable energy resources

Keywords: coastal disaster prevention and mitigation, real-time coastal disaster prevention and mitigation system, storm surge, storm waves, tsunami, typhoon, renewable energy, sea-level rise, regional climate projection modelling

1. Chisale SW and Lee HS*. 2023. Evaluation of Barriers and Solutions to Renewable Energy Acceleration in Malawi, Africa, using AHP and fuzzy TOPSIS approach. Energy Sustain Dev. 76: 101272. 
2. Chreng K, Lee HS*, Tuy S. 2022. A Hybrid Model for Electricity Demand Forecast Using Improved Ensemble Empirical Mode Decomposition and Recurrent Neural Networks with ERA5 Climate Variables. Energies, 15(19):7434.  
3. Tuy S., Lee H.S.*, and Chreng K. 2022. Integrated assessment of offshore wind power potential using Weather Research and Forecast (WRF) downscaling with Sentinel-1 satellite imagery, optimal sites, annual energy production and equivalent CO2 reduction. Renew. Sust. Energ. Rev., 163, 112501. 

軽元素で構成される物質の機能性を利用した水素製造，水素貯蔵，アンモニア合成，物質変換技術に関する研究開発。厳密に管理された特殊環境下における試料合成，種々の熱分析，構造評価，分光分析を用いた多角的な物性評価を通した反応メカニズムの解明。
Research on hydrogen production, hydrogen storage, ammonia synthesis, and material conversion based on functional properties of light elements. Understanding reaction mechanism by original sample synthesis methods and various analyses from wide points of view.

Keywords: Hydrogen, Hydrogen storage, Hydrogen production, Energy conversion, Nitrides, Ammonia, Sustainable material science, Analysis technique

1. Catalysis of Sodium Alloys for Ammonia Synthesis around Atmospheric Pressure, ACS Applied Energy Materials, 12, 52, 2022. 
2. Systematic Study on Nitrogen Dissociation and Ammonia Synthesis by Lithium and Group 14 Element Alloys, ACS Applied Energy Materials, 5,  4765, 2022. 
3. Improvement of Kinetics of Ammonia Synthesis at Ambient Pressure by the Chemical Looping Process of Lithium Hydride, The Journal of Physical Chemistry C, 126, 2403, 2022.

水素を中心としたエネルギー供給システムの社会総合リスク評価手法の開発，低炭素社会とサーキュラーエコノミーを指向した自動車ライフサイクルアセスメント手法の開発，持続可能な地域コミュニティマネジメント手法の開発
Development of a comprehensive social risk assessment method for hydrogen-centered energy supply systems, Development of an automobile life cycle assessment method for a low-carbon society and circular economy, Development of sustainable local community management methods

Keywords: Mobility Commons, Community Transport, Material Flow Analysis, Global Reuse, Fair Trade, Social Comprehensive Risk, Automobile, Hydrogen Economy, International Trade

1. ★, Detecting illegal intercountry trade of mercury using discrepancies in mirrored trade data, Environmental Science & Technology, 56(19), 13565-13572, 20220923
2. ★, Review of life cycle assessment for automobiles: A meta-analysis-based approach, RENEWABLE & SUSTAINABLE ENERGY REVIEWS, 159, 202205Link to Paper Search Results by DOI
3. Near-term location planning of hydrogen refueling stations in Yokohama City, INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, 46(23), pp. 12272-12279, 20210331

建築物の省エネルギー技術の開発，特に，ヒートポンプの適用による空調エネルギー削減，地中熱や貯留水等の再エネ熱活用，蓄熱による再エネ需給調整
Development of energy-saving systems in buildings, mainly heat pump systems for air conditioning, utilization of renewable heats such as ground sources and reservoir water sources, and adjustment between renewable power supply and heat demands through thermal energy storage

Keywords: sustainable energy, unutilized energy, heat pump systems, energy savings

1. Applicability of entrainment law to heat release processes in reservoir-source heat pump systems, APPLIED THERMAL ENGINEERING, 185, 20210225
2. STUDY OF THE MOST SUITABLE OPERATION OF GROUND SOURCE HEAT PUMP SYSTEM FOR TOTALLY ELECTRIFIED HEATING AND COOLING SYSTEM-A practical example in a hospital-:- A practical example in a hospital -, AIJ J. Technol. Des., 15(31), 823-826, 2009
3. B-13 Feasibility Study of Ground Source Heat Pump System in Non-Residential Buildings, 21(1), 149-152, 20090818