14 results
Search Results
Now showing 1 - 10 of 14
Article A Benchmark of Expert-Level Academic Questions to Assess AI Capabilities(Nature Portfolio, 2026) Phan, Long; Gatti, Alice; Li, Nathaniel; Khoja, Adam; Kim, Ryan; Ren, Richard; Scaramuzza, Davide; Park, JongeeBenchmarks are important tools for tracking the rapid advancements in large language model (LLM) capabilities. However, benchmarks are not keeping pace in difficulty: LLMs now achieve more than 90% accuracy on popular benchmarks such as Measuring Massive Multitask Language Understanding(1), limiting informed measurement of state-of-the-art LLM capabilities. Here, in response, we introduce Humanity's Last Exam (HLE), a multi-modal benchmark at the frontier of human knowledge, designed to be an expert-level closed-ended academic benchmark with broad subject coverage. HLE consists of 2,500 questions across dozens of subjects, including mathematics, humanities and the natural sciences. HLE is developed globally by subject-matter experts and consists of multiple-choice and short-answer questions suitable for automated grading. Each question has a known solution that is unambiguous and easily verifiable but cannot be quickly answered by internet retrieval. State-of-the-art LLMs demonstrate low accuracy and calibration on HLE, highlighting a marked gap between current LLM capabilities and the expert human frontier on closed-ended academic questions. To inform research and policymaking upon a clear understanding of model capabilities, we publicly release HLE at https://lastexam.ai.Article Calcium Phosphate Honeycomb Scaffolds With Tailored Microporous Walls Using Phase Separation-Assisted Digital Light Processing(MDPI, 2025) Kim, Gyu-Nam; Park, Jae-Hyung; Song, Jae-Uk; Koh, Young-Hag; Park, JongeeThe present study reports on the manufacturing of biphasic calcium phosphate (BCP) honeycomb scaffolds with tailored microporous walls using phase separation-assisted digital light processing (PS-DLP). To create micropores in BCP walls, camphene was used as the pore-forming agent for preparing BCP suspensions, since it could be completely dissolved in photopolymerizable monomers composed of triethylene glycol dimethacrylate (TEGDMA) and polyethylene glycol diacrylate (PEGDA) and then undergo phase separation when placed at 5 degrees C. Therefore, solid camphene crystals could be formed in phase-separated BCP layers and then readily removed via sublimation after the photopolymerization of monomer networks embedding BCP particles by DLP. This approach allowed for tight control over the microporosity of BCP walls by adjusting the camphene content. As the camphene content increased from 40 to 60 vol%, the microporosity increased from similar to 38 to similar to 59 vol%. Consequently, the overall porosity of dual-scale porosity scaffolds increased from similar to 51 to similar to 67 vol%, while their compressive strength decreased from similar to 70.4 to similar to 13.7 MPa. The mass transport ability increased remarkably with an increase in microporosity.Article Citation - WoS: 51Citation - Scopus: 52A Dft Study of Tic3 as Anode Material for Li-Ion Batteries(Elsevier, 2023) Park, Jongee; Fatima, Syeda AfrinishTwo-dimensional monolayer titanium carbide (TiC3) was used to study as a suitable electrode material for lithium-ion batteries with first principles calculation. The monolayer TiC3 showed excellent structural stability, high mechanical stiffness and good electronic conductance behaviour. The adsorption of Li on the carbon rich composition of titanium carbide monolayer is predicted to be favourable. TiC3 structure has remained the same, preserving its metallicity after Li adsorption with attaining high electrical conductivity during lithiation/delithiation process. Especially, the theoretical specific capacity of TiC3 monolayer is high, up to 1916 mAh/g, which is five times higher than the practical graphite. The low open circuit voltage (0.26 V) and diffusion energy barrier (0.25 eV) are also beneficial for overall performance of LIBs. Importantly, during lithiation the change in area is very small and reaches only 8.1 % for full lithiation indicating that it can avoid the large volume expansion during charge/discharge cycles. Its excellent performance, including high melting temperature, dynamical and mechanical stability, can be credited to the rigidness of the TiC3. Given these advantages, that is, high specific capacity, low Li diffusion energy barrier, low open circuit voltage and high in-plane stiffness, TiC3 monolayer can be a promising anode material for lithium-ion batteries.Article Citation - WoS: 8Citation - Scopus: 8Two-Dimensional Carbon Rich Titanium Carbide (tic3) as a High-Capacity Anode for Potassium Ion Battery(Elsevier, 2024) Fatima, Syeda Afrinish; Park, JongeeIn recent years, two-dimensional (2D) materials, particularly MXenes such as titanium carbide, have gained significant interest for energy storage applications. This study explores the use of potassium-adsorbed TiC3 nanosheets as potential anode materials for potassium ion batteries (KIBs), utilizing first-principles calculations. The investigated electronic, mechanical, and thermal properties of TiC3 demonstrate its suitability as an anode material. The incorporation of potassium into the host material enhances electronic conductivity while maintaining a stable layered structure. Our findings reveal promising adsorption behavior of potassium in TiC3, leading to a high theoretical specific capacity of 958 mAh/g, coupled with a low energy barrier of 0.19 eV for potassium migration, which is indicative of superior electrochemical performance. Moreover, despite the high potassium content, the electrode material shows limited volume expansion of 11.3 %, suggesting good cyclability. Additionally, the equilibrium distance between potassium and TiC3, measured at 3.11 & ring;A, exceeds that of lithium and TiC3 (2.56 & ring;A), potentially augmenting the material's flexibility. Consequently, TiC3 emerges as a promising candidate for KIB anode materials.Article Citation - WoS: 6Citation - Scopus: 5Computational Analysis of Tic3 as a High-Efficiency Anode for Calcium-Ion Batteries(Elsevier, 2024) Park, Jongee; Fatima, Syeda AfrinishA comprehensive analysis of the structural, electronic, and thermal properties of TiC3 has been conducted. The calculated thermal expansion coefficient throughout a significant portion of the temperature range leads to a negative value underscoring the material's significance. The carbon-rich polytype of titanium carbide (TiC3) is being proposed for the first time as an anode material for calcium-ion batteries (CIB). The adsorption of Ca2+ ions has been determined to be favorable, with high accommodation of guest atoms and sufficiently rapid ionic mobility. The total volume expansion for a maximum Ca2+ adsorbed TiC3 configuration is calculated to be 8.2 %, which is lower compared to other anode materials for CIBs. Through the calciation of TiC3 up to the highest Ca2+ concentration (Ca7TiC3), an exceptionally high theoretical capacity of 2236 mAh/g has been achieved. Regarding battery rate capability, the lowest diffusion barrier calculated is 0.13 eV, with a remarkably high diffusion coefficient along the corresponding pathway equal to 10-3 cm2/s, indicating the ease of Ca ion movement within the host material. Furthermore, the equilibrium distance (2.5 & Aring;) between our host and guest atoms indicates a robust interaction between them. These findings lay the groundwork for the development of high-performance anode materials for CIBs.Master Thesis Su Arıtımı için Fotokatalitik Titanyum Dioksit Tozlarının Sol-jel Süreciyle Hazırlanması(2018) Mohammed, Ahmed Hafedh Mohammed; Park, Jongee; Park, Jongee; Park, Jongee; Metallurgical and Materials Engineering; Metallurgical and Materials EngineeringBu çalışma, yüksek fotokatalitik aktivite elde etmek için tetra-izopropoksit öncülü kullanılarak sol-gel yöntemiyle TiO 2 nanopartikülleri elde edilmesinin detaylarını içermektedir. Sol-gel yönteminde, farklı asitlerin (Asetik asit, Hidroklorik asit ve Nitrik asit) ve katalizör olarak hidroklorik asit kullanılarak elde edilen farklı pH değerlerinin etkileri çalışılmıştır. Sentezlenen numunelerden biri kullanılarak, kalsinasyon sıcaklığının sentezlenen TiO 2 'nin özelliklerine etkisi, 450, 550 ve 650°C olmak üzere farklı sıcaklıklar için araştırılmıştır. 550°C'de kalsine edilen tüm numuneler XRD, SEM ve UV-Vis spektrofotometre ile karakterize edilmiştir. Hidroklorik asit kullanılarak (pH: 4) hazırlanan titanyum dioksit çözeltisi, cam altlık üzerine daldırarak kaplama tekniği kullanılarak farklı döngülerle (1, 3 ve 5 defa) kaplanmıştır. Tüm TiO 2 kaplanmış camlar UV-Vis spektrometre, UV-Vis spektrofotometre ve temas açısı ölçümleri ile analiz edilmiştir. Sonuçlar farklı türdeki asitlerle sadece TiO 2 'nin anataz fazının farklı kristal boyut, kristallik ve şekillerde elde edildiğini göstermiş ve farklı asitlerle TiO 2 oluşumunun mekanizması detaylı olarak tartışılmıştır. Farklı pH değerleri için, 4, 2.8 ve 1.5 pH değerlerinde sadece anataz tipi TiO 2 gözlenmiştir. 3.3 pH değerindeki asidik koşulda, anataz ve çok az miktarda rutil elde edilmiştir. İlave olarak, kalsinasyon sıcaklığı arttıkça anataz tipi TiO 2 'nin kristalliğinin ve kristal boyutunun arttığı görülmüştür. Hidroklorik asitle (pH: 4) sentezlenen TiO 2 tozu en yüksek fotokatalitik aktiviteyi göstermiş ve bu tozun UV ışını altında metilen mavisi ile 30, 60 ve 90 dakikalarda elde edilen fotobozunum verimleri sırasıyla %76.2, %95 ve %98.1 bulunmuştur. Son olarak, 5 defa TiO2 kaplanmış cam süperhidrofobiklik göstermiş ve 7 saatlik UV ışını altında fotobozunum verimi %67 bulunmuştur.Article Citation - WoS: 6Citation - Scopus: 6Diethanolamine Modified Perovskite-Substrate Interface for Realizing Efficient Esl-Free Pscs(Mdpi, 2023) Sajid, Sajid; Alzahmi, Salem; Wei, Dong; Ben Salem, Imen; Park, Jongee; Obaidat, Ihab M.Simplifying device layout, particularly avoiding the complex fabrication steps and multiple high-temperature treatment requirements for electron-selective layers (ESLs) have made ESL-free perovskite solar cells (PSCs) attractive. However, the poor perovskite/substrate interface and inadequate quality of solution-processed perovskite thin films induce inefficient interfacial-charge extraction, limiting the power conversion efficiency (PCEs) of ESL-free PSCs. A highly compact and homogenous perovskite thin film with large grains was formed here by inserting an interfacial monolayer of diethanolamine (DEA) molecules between the perovskite and ITO substrate. In addition, the DEA created a favorable dipole layer at the interface of perovskite and ITO substrate by molecular adsorption, which suppressed charge recombination. Comparatively, PSCs based on DEA-treated ITO substrates delivered PCEs of up to 20.77%, one of the highest among ESL-free PSCs. Additionally, this technique successfully elongates the lifespan of ESL-free PSCs as 80% of the initial PCE was maintained after 550 h under AM 1.5 G irradiation at ambient temperature.Article First-Principles Investigation of Kaolinite/YSZ Heterostructure for Solar-Driven Photocatalytic Hydrogen Production(Pergamon-Elsevier Science Ltd, 2025) Park, Jongee; Yu, Eunmi; Fatima, Syeda AfrinishThis work employs density functional theory (DFT) to elucidate the structural, electronic, and photocatalytic properties of a kaolinite/yttria-stabilized zirconia (Kaol/YSZ) heterostructure tailored for solar-driven hydrogen generation. The lattice mismatch between Kaol(001) and YSZ(111) was determined to be 4.4 % along the a-axis and 2.2 % along the b-axis. Two interface terminations were modeled: an O-terminated Si-O surface and an OH-terminated Al-OH surface. The OH-terminated interface demonstrated a stronger interfacial binding energy (-9.32 eV per cell) and enhanced thermodynamic stability, indicating its suitability for photocatalytic water splitting. Electronic structure analysis reveals that the Kaol/YSZ heterostructure exhibits a narrowed band gap of 1.46 eV relative to the isolated components, which promotes enhanced visible-light absorption. A type-II band alignment is observed, facilitating photoinduced electron transfer from the conduction band of YSZ to the conduction band of Kaol and promoting efficient charge separation. Hirshfeld charge analysis confirms the existence of a built-in electric field at the interface that further drives charge migration. Calculated optical absorption spectra shows a red shift in the heterostructure's absorption edge, extending its photoresponse into the visible region. Under simulated solar irradiation, photogenerated electrons preferentially migrate to Kaol for proton reduction, while holes remain on the YSZ surface to oxidize water, enabling simultaneous H2 evolution and O2 evolution pathways. These findings highlight the promise of the Kaol/YSZ heterostructure as a robust visible-light photocatalyst for sustainable hydrogen production and environmental remediation.Master Thesis Alumina ve Titanya eş-doplanmış zirkonya seramiklerinin mekanik ve biyolojik özellikleri(2017) Ağaç, Özlem; Park, JongeeGünümüzde daha doğala yakın göründüğünden dolayı zirkonya diş hekimliğinde oldukça yaygın olarak kullanılmaktadır. Ayrıca, zirkonya‟nın yüksek sertliği ve kırılma tokluğu, biyolojik uyumluluğu ve estetik görünümü sebebiyle de en çok tercih edilen seramik malzemelerin arasında yer alır. Bu çalışmada, mekanik öğütme yöntemi ile katkı maddeleri farklı oranlarda (0 ve % 2.0) % 3 mol yttria (Y2O3) içeren zirkonya içerisine sırasıyla katılmıştır. Şekillendirilen numuneler sırasıyla 1350, 1450 ve 1550 °C‟ de 2 saat süresince sinterlenmiş olup, katkı maddelerinin etkilerini gözlemlemek için yoğunluk, sertlik, kırılma tokluğu ve hücre tutunma oranı hesaplanmıştır. Sertlik ve kırılma tokluğu hesapları için Vicker‟s sertlik yöntemi kullanılmıştır. X Ray Kırınım Yöntemi (XRD) ile yalnızca titanya içeren ve hem titanya hem de alumina içeren numunelerin kristal faz analizleri yapılmıştır. Taramalı Elektron Mikroskobu (SEM) kullanılarak numunelerin tane boyutları hesaplanmıştır ve yüzey morfolojisi incelenmiştir. Deney sonuçlarına göre katkı malzemelerinin oranı arttıkça, yoğunluğun düştüğü görülmüştür. Mekanik özellikler göz önünde bulundurulduğunda en yüksek sertlik ve tokluk değerleri % 0.5 TiO2 ve % 1.0 Al2O3 numunelerinde elde edilmiştir. Titanya ve aluminanın zirkonya içerisine katılması faz değişimine sebep olmamıştır ancak tane boyutunu küçültmüştür. Ayrıca, katkı maddeleri numune yüzeyine hücrelerin tutunmasını ve büyümesini de olumlu yönde etkilemiştir.Article Citation - WoS: 10Citation - Scopus: 10Computational Insight of Lithium Adsorption and Intercalation in Bilayer Tic3(Pergamon-elsevier Science Ltd, 2024) Park, Jongee; Fatima, Syeda AfrinishLithium-ion batteries (LIBs) have gained significant attention owing to their long lifespan. However, these batteries offer unmatched energy storage capacity and suffer from restricted lithium-ion mobility within the electrodes. Here, we employ first-principles calculation to investigate the two-dimensional TiC3 bilayer material. The results exhibit a remarkably high specific capacity of 1277 mAh/g and a low diffusion energy barrier of 0.12 eV. The TiC3 bilayer is anticipated to show high electrical conductivity, maintaining its metallicity due to strong bonding with four Li atoms. Additionally, its high thermal and dynamic stabilities are expected to significantly enhance the battery performance. Notably, the AB stacking bilayer TiC3 experiences a mere 6.01 % increase in volume, considerably smaller compared to the 28 % increase observed in the SiC bilayer. This suggests that TiC3 bilayers remain intact even at the highest concentration of lithium adsorptions. We also explored the solidelectrolyte interface (SEI) formation at the outset of battery operation using reactive force field molecular dynamics simulation. The reactive products of SEI are nicely matched with previous experimental and theoretical findings. All these intriguing properties position the TiC3 bilayer as an exceptionally promising material for use in LIBs.