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Transactions of Nonferrous Metals Society of china 2015年第12期25卷 4040-4045页

作者： c.w.nahm Semiconductor ceramics Laboratory Department of Electrical Engineering Dongeui University

The effect of sintering temperature on microstructure and varistor properties of Zn-V-O-based ceramics incorporated with Mn-Nb-Tb was investigated. The results showed that the increase of sintering temperature in the range from 875 to 950 °c decreased the densities of sintered pellets in the range of 5.55 to 5.45 g/cm3 and increased the average grain size in the range of 4.1 to 8.8 ？m. The breakdown field decreased noticeably from 7443 to 1064 V/cm with increasing sintering temperature from 875 to 950 °c. The varistor ceramics sintered at 900 ？c exhibited nonlinear properties, with 49.4 in the nonlinear coefficient and 0.21 m A/cm2 in the leakage current density. The dielectric constant increased greatly from 440.1 to 2197.2 with increasing sintering temperature from 875 to 950 °c; however, the dissipation factor exhibited a fluctuation between 0.237 and 0.5. These ceramic compositions and sintering conditions can be applied to the development of advanced multiplayer varistors with silver as an inner electrode.

关键词： Zn-V-O-based ceramics Mn-Nb-Tb sintering varistor properties dielectric characteristics varistor

Effect of small changes in sintering temperature on varistor properties and degradation behavior of V-Mn-Nb-Gd co-doped zinc oxide ceramics

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Transactions of Nonferrous Metals Society of china 2015年第4期25卷 1176-1184页

作者： c.w.nahm Semiconductor ceramics Laboratory Department of Electrical Engineering Dongeui UniversityBusan 614-714 Korea

The effect of small changes in sintering temperature on microstructure, electrical properties, dielectric characteristics, and degradation behavior of V-Mn-Nb-Gd co-doped zinc oxide ceramics was investigated. with the increase of sintering temperature, the densities of the sintered pellets decreased from 5.54 to 5.42 g/cm3 and the average grain size increased from 4.1 to 11.7 μm. The breakdown field(E1 m A) decreased noticeably from 7138 to 920 V/cm with the increase of sintering temperature. The varistor ceramics sintered at 900 ℃ exhibited excellent nonohmic properties, which were 66 for the nonohmic coefficient and 77 μA/cm2 for the leakage current density. concerning stability, the varistors sintered at 900 ℃ exhibited the strongest accelerated degradation characteristics, with ΔE1 mA =-9.2% for Dc accelerated degradation stress of 0.85 E1 m A at 85 °c for 24 h.

关键词： ZnO-V2O5-based ceramics sintering electrical properties degradation behavior varistor

Sintering effect on electrical properties and pulse aging behavior of(V_2O_5-Mn_3O_4-Er_2O_3 )-doped zinc oxide varistor ceramics

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Journal of Rare Earths 2014年第1期32卷 29-36页

作者： choon-w.nahm Semiconductor ceramics Laboratory Department of Electrical Engineering Dongeui University

The effect of sintering temperature on microstructure, electrical properties, and pulse aging behavior of （V2O5-Mn3O4-Er2O3）-doped zinc oxide varistor ceramics was systematically studied. when the sintering temperature increased, the average grain size increased from 6.1 to 8.7μm and the sintered density decreased from 5.52 to 5.43 g/cm3. The breakdown field decreased from 3856 to 922 V/cm with an increase in the sintering temperature up to 900 °c, whereas a further increase to 2352 V/cm at 925 °c. The nonlinear coefficient increased pronouncedly from 4.6 to 30.0 with an increase in the sintering temperature. The varistor ceramics sintered at 850 °c exhibited the best clamping characteristics, with the clamp voltage ratio of the range of 2.22-2.88 for pulse current of 1-25 A. The varistor ceramics sintered at 925 °c exhibited the strongest stability, with %ΔE1 mA/cm2=-8.8% after applying the multi-pulse current of 25 A.

关键词： ceramics sintering electrical properties pulse aging behavior varistors rare earths

Vedolizumab serum trough concentrations with and without thiopurines in ulcerative colitis: The prospective VIEwS pharmacokinetics study

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world Journal of Gastroenterology 2025年第2期31卷 102-112页

作者： Thanaboon chaemsupaphan Aviv Pudipeddi Hui-Yu Lin Sudarshan Paramsothy Viraj c Kariyawasam Melissa Kermeen Rupert w Leong Department of Gastroenterology and Liver Services Concord Repatriation General HospitalSydney 2139New South WalesAustralia Faculty of Medicine Siriraj HospitalMahidol UniversityBangkok 10700Thailand Faculty of Medicine and Health University of SydneySydney 2139New South WalesAustralia Department of Gastroenterology Tan Tock Seng HospitalSingapore 308433Singapore Faculty of Medicine and Health Sciences Macquarie UniversitySydney 2139New South WalesAustralia Department of Gastroenterology and Hepatology Blacktown HospitalSydney 2148New South WalesAustralia Blacktown clinical School Western Sydney UniversitySydney 2148New South WalesAustralia

BAcKGROUND Ulcerative colitis(Uc)is a chronic inflammatory condition requiring continuous treatment and *** is limited pharmacokinetic data on vedolizumab during maintenance therapy and the effect of thiopurines on vedolizumab trough concentrations is *** To investigate the exposure-response relationship of vedolizumab and the impact of thiopurine withdrawal in Uc patients who have achieved sustained clinical and endoscopic remission during maintenance *** This is a post-hoc analysis of prospective randomized clinical trial(VIEwS)involving Uc patients across 8 centers in Australia from 2018 to *** in clinical and endoscopic remission were randomized to continue or withdraw thiopurine while receiving *** evaluated vedolizumab serum trough concentrations,presence of anti-vedolizumab antibodies,and clinical outcomes over 48 weeks to assess exposure-response asso-ciation and impact of thiopurine *** There were 62 Uc participants with mean age of 43.4 years and 42%were *** participants received vedolizumab as maintenance therapy with 67.7%withdrew *** serum trough concentrations remained stable over 48 weeks regardless of thiopurine use,with no anti-vedolizumab antibodies ***-tients with clinical remission had higher trough concentrations at week *** quartile analysis,a threshold of>11.3μg/mL was associated with sustained clinical remission,showing a sensitivity of 82.4%,specificity of 60.0%,and an area of receiver operating characteristic of 0.71(95%cI:0.49-0.93).Patients discontinuing thiopurine required higher vedolizumab concentrations for achieving *** A positive exposure-response relationship between vedolizumab trough concentrations and Uc outcomes suggests that monitoring drug levels may be *** thiopurine did not influence vedolizumab levels,its with-drawal may necessitate higher vedolizumab trough concentrations to maintain remi

关键词： Pharmacokinetic Vedolizumab Thiopurine Ulcerative colitis Trough concentration Antibody Inflammatory bowel diseases

Microstructure, electrical and dielectric properties, and aging behavior of ZPccA varistor ceramics with Er_2O_3 doping

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Journal of Rare Earths 2015年第4期33卷 403-410页

作者： nahm choonwoo Semiconductor ceramics Laboratory Department of Electrical Engineering Dongeui University

The microstructure, electrical and dielectric properties, and Dc-accelerated aging of the ZPccA （ZnO-Pr6O11-coO- cr203-A1203） ceramics were investigated with various contents of Er203. The ceramic phases consisted of a bulk phase of ZnO grains, and a minor secondary phase of mixture of Pr6O11 and Er203. The increase of the content of doped Er203 increased the densities of sintered pellet from 5.66 to 5.85 g/cm3, and decreased the average grain size from 9.6 to 6.3 μm. with the increase of the content of doped Er203, the breakdown field increased from 2390 to 4530 V/cm, and the nonlinear coefficient increased from 28.4 to 39.1. The sample doped with 0.25 mol.% Er203 exhibited the strongest electrical stability; variation rates for the breakdown field measured at 1.0 mA/cm2, and for the non-ohmic coefficient were -3.4% and -23,8%, respectively, after application of a stress of 0.95 Eu/125 ℃/24 h.

关键词： microstructure Er203 electrical properties aging behavior varistor ceramics rare earths

Sintering effect on ageing behavior of rare earths (Pr_6O_(11)-Er_2O_3-Y_2O_3 )-doped ZnO varistor ceramics

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Journal of Rare Earths 2012年第10期30卷 1028-1033页

作者： choon-woo nahm Semiconductor ceramics Laboratory Department of Electrical Engineering Dongeui University

The electrical properties and ageing behavior of the rare earths （Pr6O11-Er2O3-Y2O3）-doped ZnO varistor ceramics were systematically investigated at sintering temperature range of 1335-1350°c. with an increase in the sintering temperature, the sintered density increased from 5.41 to 5.64g/cm3 and the average grain size increased from 5.8 to 7.9μm. The varistor properties and ageing behavior were significantly affected by small sintering temperature range of 1335-1350°c. The breakdown field noticeably decreased from 5767 to 3628V/cm with an increase in the sintering temperature. The varistor ceramics exhibited the highest nonlinear coefficient （43.2） at the sintering temperature of 1340°c. The varistor ceramics sintered at 1350°c exhibited a surprisingly excellent stability by exhibiting 0.3% in the variation rate of the breakdown field and 0.3% in the variation rate of the nonlinear coefficient for ageing stress of 0.95 E1mA/150°c/24 h.

关键词： sintering rare earths nonlinear properties ageing varistors

Nonlinear behavior of Tb_4O_7-modified ZnO-Pr_6O_(11)-based ceramics with high breakdown field

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Journal of Rare Earths 2013年第3期31卷 276-280页

作者： choon-woo nahm Semiconductor ceramics Laboratory Department of Electrical EngineeringDongeui UniversityBusan 614-714Korea

The effect of Tb407 on electrical behavior of the ZnO-Pr6Oll-based varistor ceramics was investigated. Microstructural analysis indicated that the addition of Tb407 decreased average grain size from 3.6 to 3.2 and increased the sintered density from 5.58 to 5.68 g/cm3. As the amount ofTb407 increased, the breakdown field increased from 9393 to 12437 V/cm and the nonlinear coefficient increased from 50 to 65. The varistor ceramics added with 0.5 mol.% in the amount of Tb407 exhibited an excellent stability by exhibiting 0. 1% in the variation rate of the breakdown field, 0% in the variation rate of the nonlinear coefficient, and 8.8% in the variation rate of the leakage current density for Dc-accelerated aging stress of 0.85 E1 mA/115 ℃/24 h.

关键词： doping ZnO breakdown field electrical properties varistor ceramics rare earths

A functional tacrolimus-releasing nerve wrap for enhancing nerve regeneration following surgical nerve repair

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Neural Regeneration Research 2025年第1期20卷 291-304页

作者： Simeon c.Daeschler Katelyn J.w.So Konstantin Feinberg Marina Manoraj Jenny cheung Jennifer Zhang Kaveh Mirmoeini JPaul Santerre Tessa Gordon Gregory HBorschel SickKids Research Institute Neuroscience and Mental Health ProgramTorontoONCanada Institute of Biomaterials and Biomedical Engineering University of TorontoTorontoONCanada Indiana University School of Medicine IndianapolisINUSA Division of Plastic and Reconstructive Surgery the Hospital for Sick ChildrenTorontoONCanada Translational Biology and Engineering Program Ted Rogers Centre for Heart ResearchInstitute of Biomedical EngineeringFaculty of DentistryUniversity of TorontoTorontoONCanada

Axonal regeneration following surgical nerve repair is slow and often incomplete,resulting in poor functional recovery which sometimes contributes to lifelong ***,there are no FDA-approved therapies available to promote nerve *** accelerates axonal regeneration,but systemic side effects presently outweigh its potential benefits for peripheral nerve *** authors describe herein a biodegradable polyurethane-based drug delivery system for the sustained local release of tacrolimus at the nerve repair site,with suitable properties for scalable production and clinical application,aiming to promote nerve regeneration and functional recovery with minimal systemic drug *** is encapsulated into co-axially electrospun polycarbonate-urethane nanofibers to generate an implantable nerve wrap that releases therapeutic doses of bioactive tacrolimus over 31 *** and drug loading are adjustable for applications in small and large caliber nerves,and the wrap degrades within 120 days into biocompatible *** released from the nerve wrap promotes axon elongation in vitro and accelerates nerve regeneration and functional recovery in preclinical nerve repair models while off-target systemic drug exposure is reduced by 80%compared with systemic *** its surgical suitability and preclinical efficacy and safety,this system may provide a readily translatable approach to support axonal regeneration and recovery in patients undergoing nerve surgery.

关键词： biodegradable local drug delivery nerve injury nerve regeneration nerve wrap tacrolimus

A novel method for clustering cellular data to improve classification

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Neural Regeneration Research 2025年第9期20卷 2697-2705页

作者： Diek w.wheeler Giorgio A.Ascoli center for Neural Informatics Structures&PlasticityKrasnow Institute for Advanced Study Bioengineering Department Volgenau School of Engineering George Mason University FairfaxVAUSA

Many fields,such as neuroscience,are experiencing the vast prolife ration of cellular data,underscoring the need fo r organizing and interpreting large datasets.A popular approach partitions data into manageable subsets via hierarchical clustering,but objective methods to determine the appropriate classification granularity are *** recently introduced a technique to systematically identify when to stop subdividing clusters based on the fundamental principle that cells must differ more between than within *** we present the corresponding protocol to classify cellular datasets by combining datadriven unsupervised hierarchical clustering with statistical *** general-purpose functions are applicable to any cellular dataset that can be organized as two-dimensional matrices of numerical values,including molecula r,physiological,and anatomical *** demonstrate the protocol using cellular data from the Janelia MouseLight project to chara cterize morphological aspects of neurons.

关键词： cellular data clustering dendrogram data classification Levene's one-tailed statistical test unsupervised hierarchical clustering

Low-temperature crystalline lead-free piezoelectric thin films grown on 2D perovskite nanosheet for flexible electronic device applications

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Nano Research 2019年第10期12卷 2559-2567页

作者： Jong-Hyun Kim Sang Hyo Kweon Sahn nahm KU-KIST Graduate School of converging Science and Technology Korea University145 Anam-roSeongbuk-guSeoul 02841Republic of Korea Department of Material Science and Engineering Korea University145 Anam-roSeongbuk-guSeoul 02841Republic of Korea Department of Mechanical Engineering Kobe University1-1 Rokkodai-choNadaKobe 657-8501Japan

A monolayer of Sr2Nb3Oio(SNO)is deposited on the Pt/Ti/SicwSi(Pt?Si)or Pt/Ti/polyimide(Pt-Pl)substrate by using the Langmuir-Blodgett method and employed as a seed-layer for the growth of a crystalline(Nai_xKx)NbO3(NKN)film at 350℃.The crystalline NKN film is grown along the[001]direction on the SNO/Pt-Si(or SNO/Pt-PI)*** to the presence of oxygen vacancies in the SNO seed-layer,the NKN film exhibits low ferroelectric properties and large leakage *** ameliorate these properties,the SNO/Pt-Si substrate is annealed in a 50 Torr oxygen atmosphere at 300℃,which removes the oxygen ***,the NKN film deposited on this substrate exhibits promising electrical properties,namely a dielectric constant of 278,dissipation factor of 1.7%,a piezoelectric 8nstant of 175 pm`V^-1,and a leakage current density of 6.47 x 10^-7 A cm^-2 at-0.2 MV *** electrical properties are obtained from the NKN film grown on the flexible SNO/Pt-PI substrate at 350°***,the NKN films grown on the SNO seed-layer at 350°c can be applied to electronic devices with flexible polymer substrates.

关键词： lead-free piezoelectric thin films low-temperature-deposition process two-dimensional(2D)nanosheet seed-layers polymer substrates