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Anode surface engineering of zinc-ion batteries using tellurium nanobelt as a protective layer for enhancing energy storage performance
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作者 Soobeom Lee Yeonjin Je +7 位作者 Boeun Seok Hyun Tae Kim Yong-Ryun Jo Soong Ju Oh Byoungyong Im Dae Guen Kim Sang-Soo Chee Geon-Hyoung An 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第5期113-123,共11页
Over the years,zinc-ion batteries(ZIBs)have attracted attention as a promising next-generation energy storage technology because of their excellent safety,long cycling performance,eco-friendliness,and high-power densi... Over the years,zinc-ion batteries(ZIBs)have attracted attention as a promising next-generation energy storage technology because of their excellent safety,long cycling performance,eco-friendliness,and high-power density.However,issues,such as the corrosion and dissolution of the Zn anode,limited wet-tability,and lack of sufficient nucleation sites for Zn plating,have limited their practical application.The introduction of a protective layer comprising of tellurium(Te)nanobelts onto the surface of Zn anode has emerged as a promising approach to overcome these limitations and improve the electrochemical behav-ior by enhancing the safety and wettability of ZIBs,as well as providing numerous nucleation sites for Zn plating.In the presence of a Te-based protective layer,the energy power density of the surface-engineered Zn anode improved significantly(ranging from 310 to 144 W h kg^(-1),over a power density range of 270 to 1,800 W kg^(-1)),and the lifespan capability was extended.These results demonstrate that the proposed strategy of employing Te nanobelts as a protective layer holds great promise for enhancing the energy storage performance of zIBs,making them even more attractive as a viable energy storage solution forthefuture. 展开更多
关键词 Zn ion battery ANODE Protective layer TELLURIUM NANOBELT
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Characterization of smooth muscle, enteric nerve, interstitial cells of Cajal, and fibroblast-like cells in the gastric musculature of patients with diabetes mellitus 被引量:11
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作者 Kyung Sik Park Kwang Bum Cho +7 位作者 Il Seon Hwang Jae Hyung Park Byung Ik Jang Kyeong Ok Kim Sung Woo Jeon Eun Soo Kim Chang Sik Park Joong Goo Kwon 《World Journal of Gastroenterology》 SCIE CAS 2016年第46期10131-10139,共9页
AIM To investigate histologic abnormalities in the gastric smooth muscle of patients with diabetes mellitus(DM).METHODS Full-thickness gastric specimens were obtained from patients undergoing surgery for gastric cance... AIM To investigate histologic abnormalities in the gastric smooth muscle of patients with diabetes mellitus(DM).METHODS Full-thickness gastric specimens were obtained from patients undergoing surgery for gastric cancer. H&E stain and Masson's Trichrome stain were performed to assess the degree of fibrosis. Immunohistochemical staining using various antibodies was also performed [antibodies against protein gene product 9.5(PGP9.5), neuronal nitric oxide synthase(n NOS), vasoactive intestinal peptide(VIP), neurokinin-1(NK1) receptor, c-Kit, and platelet-derived growth factor receptor-alpha,(PDGFRα)]. Immunofluorescent staining and evaluation with confocal microscopy were also conducted.RESULTS Twenty-six controls and 35 diabetic patients(21 shortduration patients and 14 long-duration patients) were included. There were no significant differences in basic demographics between the two groups except in mean body mass index(BMI)(higher in the DM group). Proportions of moderate-to-severe intercellular fibrosis in the muscle layer were significantly higher in the DM group than in the control group(P < 0.01). On immunohistochemical staining, c-Kit- and PDGFRα-positive immunoreactivity were significantly decreased in the DM group compared with the control group(P < 0.05). There were no statistically significant differences in PGP9.5, n NOS, VIP, and neurokinin 1 expression. On immunofluorescent staining, cellularity of interstitial cells of Cajal(ICC) was observed to decrease with increasing duration of DM.CONCLUSION Our study suggests that increased intercellular fibrosis, loss of ICC, and loss of fibroblast-like cells are found in the smooth muscle of DM patients. These abnormalities may contribute to changes in gastric motor activity in patients with DM. 展开更多
关键词 Diabetes mellitus Interstitial cells of Cajal Fibroblast-like cell GASTROPARESIS Enteric nerve system
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Growth of BaTiO_3-Ag hybrid composite films at room temperature by aerosol deposition 被引量:2
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作者 Young Joon YOON Sung Hwan CHO +3 位作者 Jihoon KIM Hyo Tae KIM Hong Koo BAIK Jong-Hee KIM 《中国有色金属学会会刊:英文版》 CSCD 2012年第S3期735-739,共5页
Barium titanate (BaTiO3) and silver (Ag) composite film with high dielectric constant was grown at room temperature by an aerosol deposition method.The dielectric constant increases by 0.5 times after adding Ag to the... Barium titanate (BaTiO3) and silver (Ag) composite film with high dielectric constant was grown at room temperature by an aerosol deposition method.The dielectric constant increases by 0.5 times after adding Ag to the BaTiO3 matrix,compared with pure BaTiO3.The high dielectric constant can be attributed to the percolation effect of Ag inclusions in the BaTiO3 matrix.The Ag was present in the form of discrete layer in the BaTiO3 film.The dielectric properties of BaTiO3 Ag were discussed in detail taking into account the changes in microstructures. 展开更多
关键词 composites PERCOLATION aerosol deposition BATIO3 AG
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Fabrication of ultrafine Nd-Fe-B powder by a modified reduction-diffusion process 被引量:1
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作者 JANG T.S. LEE D.H. +2 位作者 CHOI C.J. SEO W.S. LEE Y.H. 《Rare Metals》 SCIE EI CAS CSCD 2006年第z2期223-226,共4页
In order to obtain ultrafine Nd-Fe-B powder, a spray-dried precursor was treated by reduction-diffusion (R/D) process. And, unlike the conventional R/D process, calcium reduction that is a crucial step for the formati... In order to obtain ultrafine Nd-Fe-B powder, a spray-dried precursor was treated by reduction-diffusion (R/D) process. And, unlike the conventional R/D process, calcium reduction that is a crucial step for the formation of Nd2Fe14B was performed without conglomerating the precursor with Ca powder. By adopting this modified process, it is possible to synthesize the hard magnetic Nd2Fe14B at the reaction temperature as low as 850 ℃. The average size of Nd2Fe14B particles that are uniformly distributed in the optimally treated powder was <<1 μm. Most Nd2Fe14B particles were enclosed with thin layers of Nd-rich phase. Typical magnetic properties of such powder without eliminating impurity CaO were iHc=~5.9 kOe, Br=~5.5 kG, and (BH)max=~6 MGOe. 展开更多
关键词 NdFeB powder spray drying reduction-diffusion process ND2FE14B magnetic powder
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Formation of ZSM-5 on Silicon Carbide Fibers for Catalytic Support
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作者 Yoon-joo Lee Dong-geun Shin +3 位作者 Younghee Kim Woo-teck Kwon Soo-ryong Kim Doh-hyung Riu 《材料科学与工程(中英文B版)》 2016年第5期211-217,共7页
关键词 ZSM-5 碳化硅纤维 催化剂 SIC纤维 纤维表面 先驱体聚合物 晶体生长 粘结性能
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简单水热法合成石墨-CdSe复合材料及其光催化降解有机染料(英文) 被引量:4
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作者 OH Won-Chun CHEN Mingliang +2 位作者 CHO Kwangyoun KIM Cheolkyu MENG Zeda 《催化学报》 SCIE EI CAS CSCD 北大核心 2011年第10期1577-1583,共7页
A graphene-CdSe composite was synthesized by a facile hydrothermal method,and characterized by X-ray diffraction,scanning electron microscopy with energy dispersive X-ray analysis,transmission electron microscopy and ... A graphene-CdSe composite was synthesized by a facile hydrothermal method,and characterized by X-ray diffraction,scanning electron microscopy with energy dispersive X-ray analysis,transmission electron microscopy and UV-vis diffuse reflectance spectrophotometry.The graphene-CdSe composite efficiently catalyzed the photodegradation of methylene blue(MB),methyl orange(MO) and rhodamine B(Rh.B) in aqueous solution under UV or visible light irradiation.The graphene-CdSe composite exhibited a higher photocatalytic activity for the MB solution. 展开更多
关键词 催化活性 有机染料 镉元素 石墨晶体
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The alignment of AlN platelets in polymer matrix and its anisotropic thermal properties 被引量:4
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作者 Chang-Yeoul Kim Thi My Linh Dang +2 位作者 Yaming Zhang Jian-Feng Yang Bo Wang 《Journal of Materiomics》 SCIE EI 2019年第4期679-687,共9页
The thermal conductivity of polymer composites can be enhanced by the vertical alignment of anisotropic aluminum nitride(AlN)platelet fillers in polymer matrices.The AlN platelets in polymer matrix were aligned in the... The thermal conductivity of polymer composites can be enhanced by the vertical alignment of anisotropic aluminum nitride(AlN)platelet fillers in polymer matrices.The AlN platelets in polymer matrix were aligned in the direction of in-plane and out-of-plane by using the doctor blading and the lamination process.The alignment of AlN plates in the out-of-plane or the in-plane direction has been confirmed by XRD and FE-SEM investigations.The polymer composite with the out-of-plane aligned AlN platelets showed almost 1.5 times or 2 times higher thermal conductivity than those with the AlN spheres or the in-plane aligned AlN platelets at the same filler content,respectively.This result could be attributed to the improvement of thermal pathway generated along the plane of platelets and the decrease of interfaces between the filler and the polymer. 展开更多
关键词 Thermal conductivity Aluminum nitride plate Polymer composite ALIGNMENT Out-of-direction In-plane direction
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Fe_2O_3对粉青裂纹釉的制备及性能影响 被引量:3
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作者 董伟霞 包启富 Cho Woo Seok 《中国陶瓷》 CAS CSCD 北大核心 2019年第1期64-69,共6页
主要利用韩国青瓷坯体在1270~1290℃还原气氛下制备粉青裂纹釉。考察了不同坯体种类、釉用氧化铁含量对粉青裂纹釉的影响。研究结果表明:合适的坯体应为收缩小,铁含量为1%~2%的瓷质浅灰色坯体有利于粉青釉的呈色和玉质感。随着氧化铁... 主要利用韩国青瓷坯体在1270~1290℃还原气氛下制备粉青裂纹釉。考察了不同坯体种类、釉用氧化铁含量对粉青裂纹釉的影响。研究结果表明:合适的坯体应为收缩小,铁含量为1%~2%的瓷质浅灰色坯体有利于粉青釉的呈色和玉质感。随着氧化铁含量的增加,釉面由白色、粉青色、绿色最后逐渐向黄色色调过渡,并且釉面的裂纹逐渐由稠密向稀疏直裂纹转化。当氧化铁含量为0.020 mol时,由于釉面吸收了红光而反射出蓝绿光,因此釉面呈现粉青色(L*=65.18, a*=-6.67, b*=1.63)。从XRD和SEM结果可知:韩国青瓷坯体结构致密,釉面中存在很多细小结构的微气泡和未被溶解的石英相对光造成漫发射,从而赋予了釉面玉质感。 展开更多
关键词 韩国青瓷坯体 仿龙泉青瓷 粉青裂纹釉 氧化铁
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还原氧化石墨烯-硒化银纳米复合材料的水热合成与表征及其活性氧物种产生(英文) 被引量:1
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作者 Lei Zhu Shu Ye +3 位作者 Asghar Ali Kefayat Ulla Kwang Youn Cho Won-Chun Oh 《催化学报》 SCIE EI CAS CSCD 北大核心 2015年第4期603-611,共9页
A visible-light photocatalyst containing Ag2Se and reduced graphene oxide(RGO) was synthesized by a facile sonochemical-assisted hydrothermal method. X-ray diffraction, scanning electron mi-croscopy with energy-disper... A visible-light photocatalyst containing Ag2Se and reduced graphene oxide(RGO) was synthesized by a facile sonochemical-assisted hydrothermal method. X-ray diffraction, scanning electron mi-croscopy with energy-dispersive X-ray analysis, and ultraviolet-visible diffuse reflectance spectros-copy results indicated that the RGO-Ag2Se nanocomposite contained small crystalline Ag2Se nano-particles dispersed over graphene nanosheets and absorbed visible light. The high crystallinity of the nanoparticles increased photocatalytic activity by facilitating charge transport. N2 adsorp-tion-desorption measurements revealed that the RGO-Ag2Se nanocomposite contained numerous pores with an average diameter of 9 nm, which should allow reactant molecules to readily access the Ag2Se nanoparticles. The RGO-Ag2Se nanocomposite exhibited higher photocatalytic activity than bulk Ag2Se nanoparticles to degrade organic pollutant rhodamine B and industrial dye Texbrite BA-L under visible-light irradiation(λ > 420 nm). The generation of reactive oxygen spe-cies in RGO-Ag2Se was evaluated through its ability to oxidize 1,5-diphenylcarbazide to 1,5-diphenylcarbazone. The small size of the Ag2Se nanoparticles in RGO-Ag2Se was related to the use of ultrasonication during their formation, revealing that this approach is attractive to form po-rous RGO-Ag2Se materials with high photocatalytic activity under visible light. 展开更多
关键词 纳米复合材料 氧化石墨 水热合成 氧化物 活性氧 硒化银 可见光照射 光催化活性
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废瓷粉在梅子青裂纹釉的应用研究 被引量:2
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作者 董伟霞 Cho Woo Seok +1 位作者 包启富 沈慧娟 《陶瓷学报》 CAS 北大核心 2018年第2期170-173,共4页
采用韩国当地原料及废瓷粉制备梅子青裂纹釉。为了改善釉面针孔及解决当地废瓷大量堆放等问题,考察废瓷粉含量对梅子青裂纹釉的影响。研究结果表明:随着废瓷粉含量的增加,釉面的裂纹逐渐由稠密向稀疏直裂纹转化,釉面梅子青色调变淡。当... 采用韩国当地原料及废瓷粉制备梅子青裂纹釉。为了改善釉面针孔及解决当地废瓷大量堆放等问题,考察废瓷粉含量对梅子青裂纹釉的影响。研究结果表明:随着废瓷粉含量的增加,釉面的裂纹逐渐由稠密向稀疏直裂纹转化,釉面梅子青色调变淡。当废瓷粉含量为3%时,釉面呈现交叉网状的细碎裂纹,梅子青色调并具有玉质感。这主要是由于釉中析出石英晶相,并且釉中有许多的小气泡存在,对光造成了漫反射和散射,因此釉面呈现玉质感。该研究结果不仅拓宽了废瓷粉在青瓷釉中的应用,而且利于保护环境,节约生产成本。 展开更多
关键词 梅子青 裂纹釉 废瓷粉 环保
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A novel chitosan nanocapsule for enhanced skin penetration of cyclosporin A and effective hair growth in vivo 被引量:1
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作者 Jin Sil Lee Youngmin Hwang +6 位作者 Hyeryeon Oh Sunghyun Kim Jin-Hwa Kim Jeung-Hoon Lee Yong Chui Shin Giyoong Tae Won II Choi 《Nano Research》 SCIE EI CAS CSCD 2019年第12期3024-3030,共7页
Hair loss due to medical conditions,such as alopecia,male pattern baldness,and cancer chemotherapy treatment,has been a comm onproblem for many in dividuals.Cyclospori n A(CsA),a fungal metabolite,has been reported to... Hair loss due to medical conditions,such as alopecia,male pattern baldness,and cancer chemotherapy treatment,has been a comm onproblem for many in dividuals.Cyclospori n A(CsA),a fungal metabolite,has been reported to be a hair growth modulatory agent and is apotential drug for hair regeneration.However,the effect of topical application of CsA is limited by its poor water solubility.Several deliverysystems developed to enhance its solubility still showed poor skin penetration.To overcome these limitations,in this study,we have developed a novel chitosan nanocapsule platform using Pluro nic F127 and chitosan without any chemical crosslinking or complicated preparati on steps for the enhanced water solubility and high tran sdermal penetration of CsA.The chitosan nanocapsules(ChiNCs)optimized in terms of structural stability by using chitosan with various molecular weights ranging from 3 to 100 kDa enhanced the skin permeation of CsA through humancadaver skin in vitro.Topical administration of the CsA loaded ChiNCs in creased the hair follicles by c.a.7 times higher than that of thecontrol group,and effectively induced hair growth in C57BL/6 mice in vivo.These results suggest that ChiNCs could be used as a platform foreffective transdermal delivery of various hydrophobic drugs. 展开更多
关键词 CHITOSAN NANOCAPSULE CYCLOSPORIN A TRANSDERMAL delivery HAIR growth
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High-Performance Perovskite Quantum Dot Solar Cells Enabled by Incorporation with Dimensionally Engineered Organic Semiconductor 被引量:1
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作者 Seyeong Lim Dae Hwan Lee +7 位作者 Hyuntae Choi Yelim Choi Dong Geon Lee Sung Beom Cho Seonkyung Ko Jongmin Choi Younghoon Kim Taiho Park 《Nano-Micro Letters》 SCIE EI CAS CSCD 2022年第12期272-285,共14页
Perovskite quantum dots(PQDs)have been considered promising and effective photovoltaic absorber due to their superior optoelectronic properties and inherent material merits combining perovskites and QDs.However,they e... Perovskite quantum dots(PQDs)have been considered promising and effective photovoltaic absorber due to their superior optoelectronic properties and inherent material merits combining perovskites and QDs.However,they exhibit low moisture stability at room humidity(20-30%)owing to many surface defect sites generated by inefficient ligand exchange process.These surface traps must be re-passivated to improve both charge transport ability and moisture stability.To address this issue,PQD-organic semiconductor hybrid solar cells with suitable electrical properties and functional groups might dramatically improve the charge extraction and defect passivation.Conventional organic semiconductors are typically low-dimensional(1D and 2D)and prone to excessive self-aggregation,which limits chemical interaction with PQDs.In this work,we designed a new 3D star-shaped semiconducting material(Star-TrCN)to enhance the compatibility with PQDs.The robust bonding with Star-TrCN and PQDs is demonstrated by theoretical modeling and experimental validation.The Star-TrCN-PQD hybrid films show improved cubic-phase stability of CsPbI_(3)-PQDs via reduced surface trap states and suppressed moisture penetration.As a result,the resultant devices not only achieve remarkable device stability over 1000 h at 20-30%relative humidity,but also boost power conversion efficiency up to 16.0%via forming a cascade energy band structure. 展开更多
关键词 CsPbI3 quantum dots Star-shaped organic semiconductors Hybrid perovskite quantum dots Solar cell stability High-efficiency photovoltaics
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Improving ionic conductivity of von-Alpen-type NASICON ceramic electrolytes via magnesium doping
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作者 Il-Seop Jang Wooseok Go +3 位作者 Bo-Ye Song Hayoung Park Yun Chan Kang Jinyoung Chun 《Journal of Advanced Ceramics》 SCIE EI CAS CSCD 2023年第5期1058-1066,共9页
NASICON (sodium (Na) superionic conductor) compounds have attracted considerable attention as promising solid electrolyte materials for advanced Na-based batteries. In this study, we investigated the improvement in io... NASICON (sodium (Na) superionic conductor) compounds have attracted considerable attention as promising solid electrolyte materials for advanced Na-based batteries. In this study, we investigated the improvement in ionic conductivities of von-Alpen-type NASICON (vA-NASICON) ceramic electrolytes by introducing a magnesium ion (Mg^(2+)) as a heterogeneous element. The optimal Mg-doped vA-NASICON exhibited a high ionic conductivity of 3.64×10^(−3) S·cm^(−1), which was almost 80% higher than that of un-doped vA-NASICON. The changes in physicochemical properties of the vA-NASICONs through the Mg introduction were systematically analyzed, and their effects on the ionic conductivities of the vA-NASICON were studied in detail. When the optimal ratio of Mg^(2+) was used in a synthetic process, the relative density (96.6%) and grain boundary ionic conductivity (σgb) were maximized, which improved the total ionic conductivity (σt) of the vA-NASICON. However, when Mg^(2+) was introduced in excess, the ionic conductivity decreased because of the formation of an undesired sodium magnesium phosphate (NaxMgyPO_(4)) secondary phase. The results of this study are expected to be effectively applied in the development of advanced sodium-based solid electrolytes with high ionic conductivities. 展开更多
关键词 NASICON solid electrolyte von-Alpen-type magnesium(Mg)doping ionic conductivity
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Recovery of cerium from glass polishing slurry 被引量:7
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作者 Jong-Young Kim Ung-Soo Kim +3 位作者 Myeong-Seop Byeon Woo-Kyu Kang Kwang-Teak Hwang Woo-Seok Cho 《Journal of Rare Earths》 SCIE EI CAS CSCD 2011年第11期1075-1078,共4页
Cerium was extracted from rare earth slurry waste used for polishing a glass substrate.Initially,glass frit and flocculant were removed by froth flotation and dissolution.The recovered rare earth slurry exhibited almo... Cerium was extracted from rare earth slurry waste used for polishing a glass substrate.Initially,glass frit and flocculant were removed by froth flotation and dissolution.The recovered rare earth slurry exhibited almost the same particle size distribution as original slurry,which could be reused as slurry for glass polishing.From the rare earth slurry,the cerium solution was obtained by an oxidative thermal treatment and subsequent chemical leaching.The cerium solution was further purified up to 94% by selective precipitation of rare earth species. 展开更多
关键词 CERIUM SEPARATION WASTE polishing slurry rare earths
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Effect of heating rate on the properties of silicon carbide fiber with chemical-vapor-cured polycarbosilane fiber 被引量:6
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作者 Tae-Eon KIM Khos-Erdene KHISHIGBAYAR Kwang Youn CHO 《Journal of Advanced Ceramics》 CSCD 2017年第1期59-66,共8页
Silicon carbide (SiC) fiber has recently received considerable attention as promising next-generation fiber because of its high strength at temperatures greater than 1300 ℃ in air.High-quality SiC fiber is primarily ... Silicon carbide (SiC) fiber has recently received considerable attention as promising next-generation fiber because of its high strength at temperatures greater than 1300 ℃ in air.High-quality SiC fiber is primarily made through a curing and heat treatment process.In this study,the chemical vapor curing method,instead of the thermal oxidation curing method,was used to prepare cured polycarbosilane (PCS) fiber.During the high temperature heat treatment of the cured PCS fiber,varied heating rates of 10,20,30,and 40 ℃/min were applied.Throughout the process,the fiber remained in the amorphous silicon carbide phase,and the measured tensile strength was the greatest when the oxygen content in the heat-treated fiber was low,due to the rapid heating rate.The fiber produced through this method was also found to have excellent internal oxidation properties.This fast,continuous process shows a great promise for the production of SiC fiber and the development of high-quality products. 展开更多
关键词 polycarbosilane (PCS) silicon carbide (SiC) fiber chemical vapor curing rapid heating rate high temperature tensile strength
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Ceramic-metal package for high power LED lighting 被引量:2
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作者 Yu Jin HEO Hyo Tae KIM +3 位作者 Sahn NAHM Jihoon KIM Young Joon YOON Jonghee KIM 《Frontiers of Optoelectronics》 2012年第2期133-137,共5页
High power light-emitting diodes (LEDs) lighting has drawn a great interest in the field of street light system in recent years. Key parameters for successful launching of LED street light in the commercial market a... High power light-emitting diodes (LEDs) lighting has drawn a great interest in the field of street light system in recent years. Key parameters for successful launching of LED street light in the commercial market are price and light efficiency, respectively, and they are greatly influenced by the materials and design factors used in high power LED package. This article presents a new design and materials processing technology to realize the solution of LED packaging with advantageous in price and performance. Cost effective materials and processing technology can be realized via thick film glass-ceramic insulating layer and silver conductor. Highly effective thermal design using direct heat dissipation to heat sink in LED package is demonstrated. 展开更多
关键词 light-emitting diodes (LEDs) package HIGH-POWER thick film heat dissipation thermal resistance
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Newly-modeled graphene-based ternary nanocomposite for the magnetophotocatalytic reduction of CO_(2) with electrochemical performance
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作者 Zambaga Otgonbayar Kwang Youn Cho +1 位作者 Chong-Hun Jung Won-Chun Oh 《Frontiers of Chemical Science and Engineering》 SCIE EI CSCD 2022年第10期1438-1459,共22页
The development of CO_(2)into hydrocarbon fuels has emerged as a green method that could help mitigate global warning.The novel structured photocatalyst is a promising material for use in a photocatalytic and magneto-... The development of CO_(2)into hydrocarbon fuels has emerged as a green method that could help mitigate global warning.The novel structured photocatalyst is a promising material for use in a photocatalytic and magneto-electrochemical method that fosters the reduction of CO_(2)by suppressing the recombination of electron−hole pairs and effectively transferring the electrons to the surface for the chemical reaction of CO_(2)reduction.In our study,we have developed a novel-structured AgCuZnS_(2)–graphene–TiO_(2)to analyze its catalytic activity toward the selective evolution of CO_(2).The selectivity of each nanocomposite substantially enhanced the activity of the AgCuZnS_(2)–graphene–TiO_(2)ternary nanocomposite due to the successful interaction,and the selectivity of the final product was improved to a value 3 times higher than that of the pure AgCuZnS_(2)and 2 times higher than those of AgCuZnS_(2)–graphene and AgCuZnS_(2)–TiO_(2)under ultraviolet(UV)-light(λ=254 nm)irradiation in the photocatalytic process.The electrochemical CO_(2)reduction test was also conducted to analyze the efficacy of the AgCuZnS_(2)–graphene–TiO_(2)when used as a working electrode in laboratory electrochemical cells.The electrochemical process was conducted under different experimental conditions,such as various scan rates(mV·s^(–1)),under UV-light and with a 0.07 T magneticcore.The evolution of CO_(2)substantially improved under UV-light(λ=254 nm)and with 0.07 T magnetic-core treatment;these improvements were attributed to the facts that the UV-light activated the electron-transfer pathway and the magnetic core controlled the pathway of electrontransmission/prevention to protect it from chaotic electron movement.Among all tested nanocomposites,AgCuZnS_(2)–graphene–TiO_(2)absorbed the CO_(2)most strongly and showed the best ability to transfer the electron to reduce the CO_(2)to methanol.We believe that our newly-modeled ternary nanocomposite opens up new opportunities for the evolution of CO_(2)to methanol through an electrochemical and photocatalytic process. 展开更多
关键词 ternary nanocomposite PHOTOCATALYTIC electrochemical CO_(2) reduction UV-LIGHT magnetic core
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Modulating the synergy of Pd@Pt core-shell nanodendrites for boosting methanol electrooxidation kinetics
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作者 Hyeon Jeong Kim Cheol Joo Moon +4 位作者 Seokhee Lee Jayaraman Theerthagiri Jong Wook Hong Myong Yong Choi Young Wook Lee 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2023年第34期153-160,共8页
The single-pot production of Pd@Pt core-shell structures is a promising approach as it offers large surface area,catalytic capability,and stability.In this work,we established a single-pot process to produce Pd@Pt cor... The single-pot production of Pd@Pt core-shell structures is a promising approach as it offers large surface area,catalytic capability,and stability.In this work,we established a single-pot process to produce Pd@Pt core-shell nanodendrites with tunable composition,shape and size for optimal electrochemical activity.Pd@Pt nanodendrites with diverse compositions were synthesized by tuning the ratios of Pd and Pt sources in an aqueous environment using cetyltrimethylammonium chloride,which functioned as both the surfactant and the reducing agent at an elevated temperature(90°C).The synthesized Pd5@Pt5 nanodendrites showed exceptional electrochemical action toward the methanol oxidation reaction related with another compositional Pd@Pt nanodendrites and conventional Pt/C electrocatalysts.In addition,Pd5@Pt5 nanodendrites exhibited good CO tolerance owing to their surface features and the synergistic effect among Pt and Pd.Meanwhile,nanodendrites with a Pt-rich surface provided exceptional catalytic active sites.Compared with the conventional Pt/C electrocatalyst,the anodic peak current obtained by Pd5@Pt5 nanodendrites was 3.74 and 2.18 times higher in relations of mass and electrochemical active surface area-normalized current density,respectively.This approach offers an attractive strategy to design electrocatalysts with unique structures and outstanding catalytic performance and stability for electrochemical energy conversion. 展开更多
关键词 Core-shell nanostructure Pd@Pt electrocatalysis One-pot synthesis Formation mechanism of nanodendrites Methanol oxidation reaction
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Stabilizing lithium deposition within bimodal porous SiO_(2)-TiO_(2) microspheres as 3D host structure
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作者 Noeul Kim Jae Hun Choi +2 位作者 Min Kim Dae Soo Jung Yun Chan Kang 《Nano Research》 SCIE EI CSCD 2024年第11期10179-10188,共10页
Three-dimensional (3D) host materials for lithium metal anodes (LMAs) have gained attention because they can mitigate volume expansion and local current density through their large surface area and suppress the dendri... Three-dimensional (3D) host materials for lithium metal anodes (LMAs) have gained attention because they can mitigate volume expansion and local current density through their large surface area and suppress the dendritic growth of lithium. Recent research on 3D host materials has focused on conductive materials;however, the benefits of 3D host materials cannot be fully utilized because lithium deposition begins at the top of the structure. Herein, we fabricate SiO_(2)-TiO_(2) composite microspheres with bimodal pore structures (bi-SiTiO) by simple spray pyrolysis. These microspheres effectively store lithium within the structure from the bottom of the electrode while preventing lithium dendrite formation. Focused ion beam-scanning transmission electron microscopy (FIB-STEM) analysis reveals that the lithiophilic properties of composite microspheres enhanced their effectiveness in storing lithium, with small pores acting as “lithium-ion sieves” for a uniform lithium-ion flux and large pores that provide sufficient volume for lithium deposition. The bi-SiTiO composite microspheres exhibit a high Coulombic efficiency of 98.5% over 200 cycles at 2.0 mA·cm^(−2) when operated in a lithium half-cell. With a high lithium loading of 5.0 mAh·cm^(−2), the symmetrical cell of the bi-SiTiO electrode sustains more than 900 h. A full cell coupled with an LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) (NCM811) cathode also exhibits enhanced electrochemical properties in terms of cycling stability and rate capability. 展开更多
关键词 lithium metal battery spray pyrolysis three-dimensional(3D)host materials bimodal pore structure lithiophilic materials
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Weave-pattern-dependent fabric piezoelectric pressure sensors based on polyvinylidene fluoride nanofibers electrospun with 50 nozzles
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作者 Da Bin Kim Ju Han +10 位作者 Sun Min Sung Min Seong Kim Bo Kyoung Choi Sung Jun Park Hyae Rim Hong Hong Je Choi Byeong Kon Kim Chung Hee Park Jong Hoo Paik Joon-Seok Lee Yong Soo Cho 《npj Flexible Electronics》 SCIE 2022年第1期699-707,共9页
Wearable pressure sensors having versatile device structures have been extensively investigated to achieve high sensitivity under mechanical stimuli.Here,we introduce piezoelectric pressure sensors based on fabrics wo... Wearable pressure sensors having versatile device structures have been extensively investigated to achieve high sensitivity under mechanical stimuli.Here,we introduce piezoelectric pressure sensors based on fabrics woven using polyvinylidene fluoride(PVDF)weft and polyethylene terephthalate(PET)warp yarns with different weave structures:1/1(plain),2/2,and 3/3 weft rib patterns.The dependence of the pressure-sensing performance on the weave pattern is demonstrated with an actual large-scale fabric up to the~2 m scale.An optimized pressure sensor with a 2/2 weft rib pattern produced a high sensitivity of 83 mV N−1,which was 245%higher than that of the 1/1 pattern.The detection performance of the optimal fabric was extensively evaluated with a variety of ambient input sources,such as pressing,bending,twisting,and crumpling,as well as various human motions.Further,a large allfabric pressure sensor with arrayed touch pixel units demonstrated highly sensitive and stable sensing performance. 展开更多
关键词 pattern fluoride piezoelectric
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