검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 47

        1.
        2025.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        산업의 고도화와 정밀함이 진행됨에 따라 공정과 부품의 수분 제어 기술의 중요도가 높아지고 있다. 이에 낮은 운영, 설치비용, 항상성 유지, 신뢰성이 확보된 고효율 제습 기술의 개발이 요구된다. 멤브레인 콘덴서는 고효율의 제습기술 로 주목받고 있으며, 무기막을 활용할 경우 가혹한 환경에 적용시킬 수 있을 것으로 기대된다. 소수성 미세다공성 물질인 실 리카라이트-1 (silicalite-1)과 친수성 메조다공성 물질인 γ-알루미나를 이용하여 재료물질의 기공 크기에 따른 멤브레인 콘덴 서의 성능을 비교하였다. 수열합성 및 이차성장을 통해 실리카라이트-1/α-알루미나 멤브레인 콘덴서을 제조하였으며, 보헤마 이트 졸 기법(boehmite sol-gel method)으로 합성한 후 실란코팅을 통해 소수성 개질된 γ-알루미나/α-알루미나 멤브레인 콘 덴서를 제조하였다. 수분 응축 실험을 진행한 결과, 실리카라이트-1/α-알루미나 멤브레인 콘덴서는 36.5%의 수분 제거율을 보였으며, γ-알루미나/α-알루미나 멤브레인 콘덴서는 51.4%의 수분 제거율을 보였다. 이는 메조 기공을 갖는 기공구조가 제 습성능에 영향을 미치는 중요한 요소임을 시사하며, γ-알루미나가 경제적 이점을 제공할 뿐만 아니라 우수한 성능을 나타내 어 산업용 제습 응용 분야를 위한 멤브레인 콘덴서에 적합한 물질로 보인다.
        4,000원
        2.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Evaporative emissions, a major cause of air pollution, are primarily produced by automobiles and can be recovered using adsorbents. This study investigated the effect of the textural properties of polyimide (PI)-based activated carbon fibers (PIACFs) on the adsorption and desorption performance of n-butane, which are a type of evaporative emissions. PI-ACFs were prepared by varying the activation time while maintaining the identical crosslinking and carbonization conditions. The surface morphology and microstructural properties of the ACFs were examined using a field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD), respectively. The textural properties of ACF (specific surface area, pore volume, and pore size distribution) were analyzed using N2/ 77 K adsorption and desorption isotherm curves. The n-butane adsorption and desorption performance were evaluated according to modified ASTM D5228. From the results, the specific surface area and total pore volume of ACFs were determined to be 680–1480 m2/ g and 0.28–1.37 cm3/ g, respectively. Butane activity (BA) of the ACFs increased from 14.1% to 37.1% as the activation time increased, and especially it was found to have highly correlated with pore volume in the 1.5–4.0 nm range.
        4,000원
        3.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Poor mechanical properties and bacterial infection are the main problems faced by dental restorative resins in clinical use. In this study, graphene quantum dots (GQDs) grafted with imidazole groups and mesoporous silica (MSN) are co-filled in a dental resin to impart excellent antimicrobial activity and mechanical properties to the dental resin. The higher specific surface area of GQDs and MSN results in an increased contact area with the resin matrix, which enhances the strength of the dental composite resin. The introduction of GQDs significantly improves the antimicrobial activity of the resin. The inhibition efficiency of the composite resin against Streptococcus mutans reached 99.9% with the addition of GQDs at only 0.2 wt.%. When MSN and GQDs are co-filled, MSN interferes with the release of GQDs, thus reducing the antimicrobial activity of the dental resin but improving the cyto-compatibility. By reasonably adjusting the amount of GQDs and MSN, the dental composite resin can exhibit excellent antimicrobial properties, mechanical properties and cyto-compatibility at the same time.
        4,500원
        4.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The ultrasonic method is an alternative to the conventional route to produce structured carbon materials, offering the advantages of synthesis in a short period of time under room temperature. The main objective of this work is to synthesize a sulfonated mesoporous carbon catalyst from a phenolic resin composed of phloroglucinol and formaldehyde. The synthesis was performed by the soft-template method in an ultrasonic processor and the product was subsequently carbonized and sulfonated for application in the esterification model reaction. Functionalization with sulfuric acid of MCS5-6 h sample brought about a decrease in porosity but simultaneously resulted in the generation of functional groups of an acidic nature. The MCS5-6 h catalyst with a sulfonic density of 1.6 mmol g− 1, surface area of 402 m2 g− 1 and pore diameter of 10.6 nm maintained in mesoporous even after acid treatment. MCS5-6 h showed excellent activity in the esterification reaction with 95% oleic acid conversion. The recyclability of MCS5-6 h was satisfactory during five reaction cycles. The present work addressed a promising alternative for the synthesis of carbon catalysts using ultrasound irradiation, thus providing an alternative with a lower cost of time and energy for large-scale production.
        4,600원
        5.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this work, the sulfonic acid group was introduced into the resorcinol–formaldehyde (RF) microspheres by the addition of p-phenolsulfonic acid during the polycondensation process of RF. The hydrophilicity of the sulfonated RF allowed KOH to infiltrate inside the microspheres, which enhanced the formation of mesopores in the carbon microspheres during the activation process by KOH. SEM and TEM observations and N2 adsorption measurements verified the formation of abundant mesopores in the porous carbon microspheres. The BET surface area of these mesoporous carbons exceeded 2000 m2/ g. In 17 m NaClO4 “water-in-salt” (WIS) electrolyte-based supercapacitor, the synthesized mesoporous carbon exhibited high specific capacitance of 170 F/g at current density of 0.5 A/g, comparable to those in regular KOH electrolyte. When graphite was used as current collectors, the symmetric cell could operate at 2.5 V, and the mesoporous carbon exhibited an energy density of 43 Wh/kg at power density of 0.25 kW/kg, and 25 Wh/kg at power density of 6.25 kW/kg, respectively, which were superior to those using Pt or stainless steel as current collectors. The mesoporous carbon/graphite was an excellent electrode in new-generation “WIS” electrolyte-based high-voltage supercapacitor due to their high energy and power density.
        4,000원
        6.
        2022.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We fabricated 3 types of ETL, mp TiO2, ZnO, and ZnO coated on mp TiO2(ZMT) to compare the photoelectric conversion efficiency (PCE) and fill factor (FF) of Perovskite solar cells. The structure of the cells was FTO/ETL/Perovskite (CH3NH3PbI3)/spiro-MeOTAD/Ag. SEM morphology assessment of the ETLs showed that mp TiO2 was porous, ZnO was flat, and the ZMT porous surface was filled with a thin layer. Via XRD measurements, the crystal structures of mp TiO2 and ZnO ETL were found to be anatase and wurtzite, respectively. The XPS patterns showing energy bonding of mp TiO2, ZnO, and ZMT O 1s confirmed these materials to be metal oxides such as ETL. The electrical characteristics of the Perovskite solar cells were measured using a solar simulator. Perovskite solar cells with ZMT ETL showed showed PCE of 10.29 % than that of conventional mp TiO2 ETL devices. This was considered a result of preventing Perovskite from seeping into the ETL and preventing recombination of electrons and holes.
        3,000원
        7.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this report, we successfully prepared nitrogen-doped porous carbon (N-PC)/manganese dioxide ( MnO2) composite for a high-performance supercapacitor. X-ray diffraction data revealed the α-MnO2 phase. Transmission electron microscopy confirmed that the nanostructured α-MnO2 nanoparticles were coated on the surface of N-PC. The N-PC/α-MnO2 composite delivered a capacitance of 525.7 F g− 1 at the charging current of 1.0 A g− 1. The higher capacitance of the composite could be owing to the synergy of MnO2 and N-PC. Besides, the electrode exhibited a 14.7% capacitance loss after 6000 charge– discharge cycles at 10 A g− 1 indicating good electrochemical stability.
        4,000원
        8.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the arsenide removal by using mesoporous CoFe2O4/ graphene oxide nanocomposites based on batch experiments optimized by artificial intelligence tools. These nanocomposites were prepared by immobilizing cobalt ferrite on graphene oxide and then characterized using various techniques, including small angle X-ray diffraction, high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy. Artificial intelligence tools associated with response surface methodology were employed to optimize the conditions of the arsenide removal process. The results showed that back propagation neural network combined with genetic algorithm was suitable for the arsenide removal from aqueous solutions by the nanocomposites based on the minimum average values of absolute errors and the value of R2. The optimal values of the four variables (operating temperature, initial pH, initial arsenide concentration, and contact time) were found to be 25.66 °C, 7.58, 10.78 mg/L and 46.41 min, and the predicted arsenide removal percentage was 84.78%. The verification experiment showed that the arsenide removal percentage was 86.62%, which was close to the predicted value. Three evaluation methods (gradient boosted regression trees, Garson method and analysis of variance) all demonstrated that the temperature was the most important explanatory variable for the arsenide removal. In addition, the arsenide removal process can be depicted with pseudo-second-order kinetics model and Langmuir isotherm, respectively. The thermodynamics investigation disclosed that the adsorption process was of a spontaneously endothermic nature. In summary, this study showed that ANN-GA was an efficient and feasible method in determining the optimum conditions for arsenic removal by CoFe2O4/ graphene oxide nanocomposites.
        4,900원
        9.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        급냉법에 의한 역 열유도상전이(RTIPS) 공정을 사용하여 mesoporous polystyrene (PS), polyethersulfone (PES) 막 을 제조하였다. 급냉법에 의한 RTIPS 공정은 급냉 및 승온 시 도포 용액 내 용매 분자들의 결정 생성 및 성장을 통해 나노 규 모의 상전이를 야기시켜 mesoporous 기공들을 형성된다. 시차주사열량계(TA: DSC) 사용해 측정된 사용 용매 dimethylformamide (DMF)와 여러 고분자 함량의 고분자용액들에 대한 엔탈피 변화와 주사현미경(SEM)을 사용하여 측정한 고분자함량에 따른 제조된 막 구조, 그리고 비표면적 분석기(BET) 사용하여 측정한 고분자 함량에 따라 제조된 막의 기공크기분포 및 표준편 차 분석을 통해 RTIPS 공정 시 상전이 거동을 살펴보았다.
        4,500원
        10.
        2019.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, activated carbon with well-developed mesopores was fabricated using kenaf short fibers as a representative biomass. Concentrated phosphoric acid was selected as an activation agent to create highly developed porous structures, and pore development was observed to occur in relation to the weight ratio of phosphoric acid and kenaf. The pore characteristics of the kenaf-based activated carbon were determined using the N2/ 77K adsorption isotherm, and its microcrystalline structure was analyzed using X-ray diffraction. The highest specific surface area (1570 m2/g) was observed when the weight ratio of phosphoric acid to kenaf was 3:1, and the highest mesopore fraction (74%) was observed at 4:1. The carbonization yield was 45–35%, which is higher than that of commercial activated carbon. The production of porous carbon material by this method offers high potential for application because it can be controlled over a wide range of average pore diameter from 2.48 to 5.44 nm.
        4,000원
        11.
        2019.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        High-level heteroatom, N and S, dual-doped graphene with an improved mesoporous structure was fabricated via facile in situ carbonization and used as metal-free cathode for non-aqueous lithium oxygen batteries. The prepared cathode delivered an ultrahigh specific capacity of 22,252 mAh/g at a current density of 200 mA/g as well as better cycling reversibility because of the larger and copious mesopores, which can promote the penetration of oxygen, electrons, and lithium ions and the ability to accommodate more discharge products, e.g., Li2O2, in Li–O2 batteries. The material had a high level of heteroatom co-doping in the carbon lattice, which enhanced the electrical conductivity and served as active sites for the oxygen reduction reaction.
        4,000원
        12.
        2019.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this article, a new type of mesoporous carbon nanoparticles (MCN) was fabricated as a potential oral delivery system of insulin to reduce the adverse reactions by hypodermic injection. The mesoporous carbon nanoparticles-carried insulin (MCNI) was studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR) compared with the blank MCNs. The Brunauer–Emmett–Teller (BET) method was utilized to calculate the specific surface area. The pore volume and pore size distribution (PSD) curves were calculated by Barrett–Joyner–Halenda (BJH) model. The entrapment efficiency (EE%) and loading content (LC%) of insulin onto the MCNs were determined by RP-HPLC. In vitro insulin release from MCNI was determined in simulated intestinal fluid. To evaluate the pharmacodynamics of MCNIs orally, the variation of glycemia of diabetic rats after oral administration of MCNIs was compared with the rats receiving hypodermic injection of insulin. Besides, the absorption of FITC-labeled MCNs in HCT-116 cells was tested. The results showed that there is significant difference between MCNs and MCNIs through SEM, TEM, and FT-IR. The entrapment efficiency, loading content and in vitro insulin release met the requirements of the pharmacodynamic study. The specific surface area, pore volume and pore size of MCNIs were significantly decreased compared to that of MCNs. The pharmacodynamics study showed that the blood sugar level was significantly decreased after the oral administration of MCNIs. The FITC-labeled MCNs showed significant absorption in HCT-116 cells. The MCNIs were successfully synthesized with commendable entrapment efficiency and loading content which preferably decreased the blood sugar in diabetes rats via oral administration.
        4,200원
        13.
        2019.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        To improve the performance of carbon nanofibers as electrode material in electrical double-layer capacitors (EDLCs), we prepare three types of samples with different pore control by electrospinning. The speciments display different surface structures, melting behavior, and electrochemical performance according to the process. Carbon nanofibers with two complex treatment processes show improved performance over the other samples. The mesoporous carbon nanofibers (sample C), which have the optimal conditions, have a high sepecific surface area of 696 m2 g−1, a high average pore diameter of 6.28 nm, and a high mesopore volume ratio of 87.1%. In addition, the electrochemical properties have a high specific capacitance of 110.1 F g−1 at a current density of 0.1 A g−1 and an excellent cycling stability of 84.8% after 3,000 cycles at a current density of 0.1 A g−1. Thus, we explain the improved electrochemical performance by the higher reaction area due to an increased surface area and a faster diffusion path due to the increased volume fraction of the mesopores. Consequently, the mesoporous carbon nanofibers are demonstrated to be a very promising material for use as electrode materials of high-performance EDLCs.
        4,000원
        14.
        2017.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Mesoporous carbon nanofibers as electrode material for electrical double-layer capacitors(EDLCs) are fabricated using the electrospinning method and carbonization. Their morphologies, structures, chemical bonding states, porous structure, and electrochemical performance are investigated. The optimized mesoporous carbon nanofiber has a high sepecific surface area of 667 m2 g−1, high average pore size of 6.3 nm, and high mesopore volume fraction of 80 %, as well as a unifom network structure consiting of a 1-D nanofiber stucture. The optimized mesoporous carbon nanofiber shows outstanding electrochemical performance with high specific capacitance of 87 F g−1 at a current density of 0.1 A g−1, high-rate performance (72 F g−1 at a current density of 20.0 A g−1), and good cycling stability (92 F g−1 after 100 cycles). The improvement of the electrochemical performance via the combined effects of high specific surface area are due to the high mesopore volume fraction of the carbon nanofibers.
        4,000원
        15.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper introduces a nitrogen-doped ordered mesoporous carbon (NOMC) derived from glucosamine with hybrid capacitive behaviors, achieved by successfully combining electrical double-layer capacitance with pseudo-capacitance behaviors. The nitrogen doping content of the fabricated NOMC reached 7.4 at% while its specific surface area (SBET) and total pore volume reached 778 m2 g−1 and 1.17 cm3 g−1, respectively. A dual mesoporous structure with small mesopores centered at 3.6 nm and large mesopores centered at 9.9 nm was observed. The specific capacitance of the reported materials reached up to 328 F g−1, which was 2.1 times higher than that of pristine CMK-3. The capacitance retention rate was found to be higher than 87.9% after 1000 charge/discharge cycles. The supplementary pseudocapacitance as well as the enhanced wettability and conductivity due to the incorporation of nitrogen heteroatoms within the carbon matrixes were found to be responsible for the excellent capacitive performance of the reported NOMC materials.
        4,000원
        16.
        2017.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Carbon nanofiber (CNF) is used as an electrode material for electrical double layer capacitors (EDLCs), and is being consistently researched to improve its electrochemical performance. However, CNF still faces important challenges due to the low mesopore volume, leading to a poor high-rate performance. In the present study, we prepared the unique architecture of the activated mesoporous CNF with a high specific surface area and high mesopore volume, which were successfully synthesized using PMMA as a pore-forming agent and the KOH activation. The activated mesoporous CNF was found to exhibit the high specific surface area of 703 m2 g−1, total pore volume of 0.51 cm3 g−1, average pore diameter of 2.9 nm, and high mesopore volume of 35.2 %. The activated mesoporous CNF also indicated the high specific capacitance of 143 F g−1, high-rate performance, high energy density of 17.9-13.0Wh kg−1, and excellent cycling stability. Therefore, this unique architecture with a high specific surface area and high mesopore volume provides profitable synergistic effects in terms of the increased electrical double-layer area and favorable ion diffusion at a high current density. Consequently, the activated mesoporous CNF is a promising candidate as an electrode material for high-performance EDLCs.
        4,000원
        19.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We report a facile method for preparing KIT-1 mesoporous silicates with two different macroporous structures by dual templating. As a template for macropores, polystyrene (PS) beads are assembled into uniform three dimensional arrays by ice templating, i.e., by growing ice crystals during the freezing process of the particle suspension. Then, the polymeric templates are directly introduced into the precursor-gel solution with cationic surfactants for templating the mesopores, which is followed by hydrothermal crystallization and calcination. Later, by burning out the PS beads and the surfactants, KIT-1 mesoporous silicates with macropores are produced in a powder form. The macroporous structures of the silicates can be controlled by changing the amount of EDTANa4 salt under the same templating conditions using the PS beads and inverse-opal or hollow structures can be obtained. This strategy to prepare mesoporous powders with controllable macrostructures is potentially useful for various applications especially those dealing with bulky molecules such as, catalysis, separation, drug carriers and environmental adsorbents.
        4,000원
        20.
        2016.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nitrogen (N)-doped ordered mesoporous carbons (OMCs) with a dual transition metal system were synthesized as non-Pt catalysts for the ORR. The highly nitrogen doped OMCs were prepared by the precursor of ionic liquid (3-methyl-1-butylpyridine dicyanamide) for N/C species and a mesoporous silica template for the physical structure. Mostly, N-doped carbons are promoted by a single transition metal to improve catalytic activity for ORR in PEMFCs. In this study, our N-doped mesoporous carbons were promoted by the dual transition metals of iron and cobalt (Fe, Co), which were incorporated into the N-doped carbons lattice by subsequently heat treatments. All the prepared carbons were characterized by via transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). To evaluate the activities of synthesized doped carbons, linear sweep was recorded in an acidic solution to compare the ORR catalytic activities values for the use in the PEMFC system. The dual transition metal promotion improved the ORR activity compared with the single transition metal promotion, due to the increase in the quaternary nitrogen species from the structural change by the dual metals. The effect of different ratio of the dual metals into the N doped carbon were examined to evaluate the activities of the oxygen reduction reaction.
        4,300원
        1 2 3