Photoluminescence of rare earth ions coactivated Ca₉Y(VO₄)₇ with cold, natural and warm white emission

Li, Ling,Liu, Xiaoguang,Noh, Hyeon Mi,Moon, Byung Kee,Choi, Byung Chun,Jeong, Jung Hyun Elsevier 2015 Materials chemistry and physics Vol.158 No.-

<P><B>Abstract</B></P> <P>It has been still a challenge to obtain a new single-component white-light phosphor with the vanadates as host lattices and with two types of ions as activators. A systematic Ln<SUB>1</SUB> <SUP>3+</SUP>/Ln<SUB>2</SUB> <SUP>3+</SUP> (Ln<SUB>1</SUB> <SUP>3+</SUP>/Ln<SUB>2</SUB> <SUP>3+</SUP> = Dy<SUP>3+</SUP>/Tm<SUP>3+</SUP> or Dy<SUP>3+</SUP>/Sm<SUP>3+</SUP> or Dy<SUP>3+</SUP>/Eu<SUP>3+</SUP> or Tm<SUP>3+</SUP>/Eu<SUP>3+</SUP> or Tm<SUP>3+</SUP>/Sm<SUP>3+</SUP>) coactivated Ca<SUB>9</SUB>Y(VO<SUB>4</SUB>)<SUB>7</SUB> (CYV)samples as well as their singly doped CYV phosphors have been synthesized by the traditional solid state reaction and their photoluminescence properties have been investigated. The photoluminescence properties as a function of the concentration of rare earth ions have been discussed and the tunable luminescent color was found. The warm (CYV: 1%Dy<SUP>3+</SUP>, 1%Sm<SUP>3+</SUP>), natural (CYV: 7% Tm<SUP>3+</SUP>,0.5% Eu<SUP>3+</SUP>; CYV: 1.0% Tm<SUP>3+</SUP>, 0.5% Sm<SUP>3+</SUP>), and cold (CYV: 3% Tm<SUP>3+</SUP>,0.5% Eu<SUP>3+</SUP>; CYV: 0.5% Dy<SUP>3+</SUP>,0.5% Tm<SUP>3+</SUP>; CYV: 0.5% Dy<SUP>3+</SUP>,0.7% Tm<SUP>3+</SUP>; CYV: 0.3%Dy<SUP>3+</SUP>, 0.5% Tm<SUP>3+</SUP>) white lights can be obtained. Generally, the emission intensity or lifetime of one rare earth ions decreases with increasing of the concentration of another rare earth ions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Photoluminescence properties of rare earth ions coactivated Ca<SUB>9</SUB>Y(VO<SUB>4</SUB>)<SUB>7</SUB> were investigated. </LI> <LI> The effects of rare earth ions concentration on photoluminescence have been discussed. </LI> <LI> The tunable luminescent color was found. </LI> <LI> Cold, natural and warm white emissions were obtained. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Late Paleoproterozoic ultrahigh-temperature metamorphism in the Korean Peninsula

Santosh, M.,Hu, Chao-Nan,Kim, Sung Won,Tang, Li,Kee, Weon-Seo Elsevier 2018 Precambrian Research Vol.308 No.-

<P><B>Abstract</B></P> <P>The Paleoproterozoic rock record from the Sino-Korean Peninsula was fundamental to the models on evolution of the Asian continental collage and its relationship with the amalgamation and disruption of Proterozoic supercontinents such as Columbia and Rodinia. In this study, we present results from a comprehensive investigation on the khondalites in the Hongseong area, along the western part of the Gyeonggi massif within the central Korean Peninsula involving petrography, phase equilibria forward modeling, and zircon U-Pb geochronology, REE geochemistry and Lu – Hf isotopes. The <I>P-T</I> pseudosections show that the peak mineral assemblage of garnet + sillimanite + quartz + plagioclase + K-feldspar + ilmenite in the khondalite is stable at 7.5–9.6 kbar and 895–990 °C, corresponding to ultra-high temperature (UHT) metamorphism. We also report the first finding of corundum and quartz inclusions within sillimanite enclosed in garnet porphyroblast further confirming UHT metamorphism. The interpreted <I>P-T</I> path involves decompression and exhumation along a clockwise trajectory as suggested by the retrograde textures and mineral phase equilibria modeling.</P> <P>The detrital zircon U – Pb data from the khondalite show multiple age peaks for the magmatic population suggesting Neoarchean – Paleoproterozoic provenance. Metamorphic zircons from the khondalites yield ages of 1931 ± 33 Ma, 1871 ± 11 Ma and 1866 ± 10 Ma. The spot ages range from 1923 Ma to 1832 Ma suggesting either a long-lived metamorphic event or two distinct thermal events. The REE patterns of the zircon grains also clearly distinguish the magmatic and metamorphic populations. The garnet + sillimanite assemblage is considered to represent the peak UHT assemblage and the cordierite + biotite represents the post-peak retrograde assemblage. The ca. 1923–1832 Ma ages obtained in our study from metamorphic zircon domains correlate well with similar ages reported for metamorphism associated with the amalgamation of crustal blocks within the North China Craton. Our study suggests that the Late Paleoproterozoic UHT metamorphism in the central Korean Peninsula might be part of a common event within the Sino-Korean Craton related to the tectonics of final assembly of cratonic blocks within the Columbia supercontinent. Although a substantial volume of the Paleoproterozoic basement of the Korean Peninsula was destroyed and recycled during the Neoproterozoic and Phanerozoic tectonic events, the preserved remnants provide insights into the contiguity of the basements of the Korean Peninsula and the North China Craton.</P> <P><B>Highlights</B></P> <P> <UL> <LI> First precise documentation of ultrahigh-temperature metamorphism in Central Korean Peninsula. </LI> <LI> Discovery of corundum + quartz assemblage testifying to extreme thermal conditions. </LI> <LI> Metamorphic zircon grains define ages ranging from 1923 to 1823 Ma. </LI> <LI> Correlation with the North China Craton within the Sino-Korean continental collage. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Writing Narrative Essays using E-Book Writing Software: Analyses of Students’ Digital Written Works

Kee Li Li,Abu Bakar Razali,Roselan Baki 아시아테플 2019 The Journal of Asia TEFL Vol.16 No.4

This study explores the utilization of e-book writing software as a tool for process-based writing approach to enhance the learning of ESL writing among the pre-service teachers. The study adopted a qualitative research design which was conducted using document analysis technique on digital written works of six pre-service teachers in one Institute of Teacher Education Malaysia (ITEM). The pre-service teachers were introduced to narrative essay format and i-Spring Pro 6.2 software to produce e-books. The data gathered (i.e., pre-service teachers’ digital written works) were analyzed using predetermined (i.e., a priori) codes. As induced from the findings, the utilization of e-book writing software as a tool for process-based writing approach is found to enhance the learning of ESL writing among the pre-service teachers, which is evident from their improved accuracy of genre and message, fulfillment of task requirements, use of grammar, spelling, and punctuation, originality, coherence and organization, and use of multimedia in text presentation. These positive results indicate that the utilization of e-book writing software as a tool for process-based writing approach in writing narrative essay type is beneficial to expose pre-service teachers to a more meaningful, fun, and engaging way of learning and practicing ESL writing.

The Role of Digital Technologies in Facilitating the Learning of ESL Writing among TESL Pre-Service Teachers in Malaysia : A Review of the Literature

Kee Li Li,Abu Bakar Razali,Nooreen Noordin,Arshad Abd Samad 아시아영어교육학회 2018 The Journal of Asia TEFL Vol.15 No.4

Effects of Digital Writing Software as a Tool for Process Approach to Writing on Teacher Trainees’ Academic Writing Performance

Kee Li Li,Abu Bakar Razali,Arshad Abd Samad,Nooreen Noordin 아시아영어교육학회 2020 The Journal of Asia TEFL Vol.17 No.4

Knowledge about academic writing is important to be promoted among the community in Institutes of Teacher Education Malaysia (ITEMs) as the teacher trainees will need to teach these academic writing skills to their students in the future. Additionally, the amalgamation of digital technologies and instructional practice is known to be able to ignite the change in the teacher trainees’ learning of academic writing. As such, this study was conducted by adopting a single group quasi-experimental research design to investigate the effects of digital writing software as a tool for process approach to writing on teacher trainees’ academic writing performance. The study was done on 10 teacher trainees at one ITEM using pre- and post-tests, observation, and reflective journal. Findings indicate that the use of digital writing software as a tool for process approach to writing does improve the teacher trainees’ academic writing performance. The eclectic approach proposes an effective way of enhancing the writing process and increasing the teacher trainees’ motivation to write digital conceptual papers. The use of digital writing software as a tool for process approach to writing can be carried out over an extended duration to develop better comprehension and practice of academic writing.

The Predictive Value of Intraoperative Esophageal Functional Luminal Imaging Probe Panometry in Patients With Achalasia Undergoing Peroral Endoscopic Myotomy: A Single-center Experience

Li-Chang Hsing,KyungMin Choi,Kee Wook Jung,Segyeong Joo,Nayoung Kim,Ga Hee Kim,Hee Kyong Na,Ji Yong Ahn,JeongHoon Lee,Do Hoon Kim,Kee Don Choi,Ho June Song,Gin Hyug Lee,Hwoon-Yong Jung 대한소화기 기능성질환·운동학회 2022 Journal of Neurogastroenterology and Motility (JNM Vol.28 No.3

Background/AimsWe evaluated the clinical significance and prognostic power of functional luminal imaging probe (FLIP) panometry in patients with achalasia treated with peroral endoscopic myotomy (POEM), and examined the clinical parameters associated with symptomatic improvement and the presence of contractility (POC) following POEM. MethodsWe reviewed the electronic medical records of patients with achalasia treated with FLIP panometry and POEM at a tertiary teaching hospital in Seoul, Republic of Korea. Follow-up examination was composed of esophageal manometry and questionnaires on symptoms. We analyzed the FLIP data by interpolating using the cubic spline method in MATLAB. ResultsWe retrospectively analyzed 33 men and 35 women (mean age: 52 ± 17 years), of whom 14, 39, and 15 patients were diagnosed with achalasia types I, II, and III, respectively. The FLIP panometry diagnoses were reduced esophagogastric junction opening (REO) with a retrograde contractile response (n = 43); REO with an absent contractile response (n = 5); REO with a normal contractile response (n = 11); and a retrograde contractile response (n = 9). Overall, the patients showed improvements in Eckardt scores following POEM from 6.48 ± 2.20 to 1.16 ± 1.15 (P < 0.01). Post-POEM symptomatic improvement was not significantly associated with any of the clinical parameters, including panometry diagnosis. Conversely, post-POEM POC was significantly associated with the presence of repetitive antegrade contractions and achalasia subtypes (both P < 0.01). ConclusionWhile FLIP panometry was not significantly associated with the clinical course of achalasia, FLIP panometry was associated with POC following POEM and may complement manometry in the functional evaluation of esophageal motility disorders.

Anti-hepatofibrogenic Effect of Turnip Water Extract on Thioacetamide-induced Liver Fibrosis

Lan Li,Dae-Hun Park,Yong-Chun Li,Seung-Kee Park,Yun-Lyul Lee,Hyon-Min Choi,Dae-Sup Han,Hyuck-Joo Yang,Eun-Hye Lee,Hyung-Kwan Jang,Young-Jin Kim,Ja-June Jang,Min-Jae Lee 한국실험동물학회 2010 Laboratory Animal Research Vol.26 No.1

Liver fibrosis is a chronic liver disease and lots of people in Korea are suffered. There are many efforts to find candidates to suppress liver fibrogenesis and several chemical-induced model or bile duct ligation model have been used to research and develop hepatic fibrogenic suppressor. From the previous study about functional effects of turnip which cultivated in Kangha Island, we got the feasibility which turnip might be able to inhibit heptatic fibrogenesis. TAA is a representative hepatic fibrosis inducer, repeated 7- weeks i.p. injection of it results in hepatic fibrosis. We compared the level of hepatic fibrosis in TAAturnip group, TAA group, and vehicle control group. Nodules-formed by TAA were observed; they were rarely shown in vehicle control group, observed in most area in TAA group, but only shown in periportal regions in TAA-turnip group. These results were confirmed through Masson's trichrom stain; fibrous structures increased in TAA group (fibrosis score: 4) but significantly decreased in TAA-turnip group (fibrosis score: 2-3). In conclusion, we got the result that turnip water extract has a potency to protect TAA-induced hepatic fibrogenesis but it is necessary further study to find its mechanism.

Physical properties of (1−<i>x</i>)K_0.5Na_0.5 NbO₃–(<i>x</i>/5)NaK₂Li₂Nb₅O₁₅ composite ceramics

Jun, Byeong-Eog,Kim, Sas Byul,Li, Guojie,Chun Choi, Byung,Kee Moon, Byung,Hyun Jeong, Jung Royal Swedish Academy of Sciences 2010 Physica scripta Vol.2010 No.t139

<P>Alkaline niobate <I>A</I>NbO<SUB>3</SUB> (<I>A</I>=K, Li and Na) ceramics were fabricated into the composites of K<SUB>0.5</SUB>Na<SUB>0.5</SUB>NbO<SUB>3</SUB> (KNN) and NaK<SUB>2</SUB>Li<SUB>2</SUB>Nb<SUB>5</SUB>O<SUB>15</SUB> (NKLN) phases. The NKLN phase was composed of completely filled tetragonal tungsten-bronze and LiNbO<SUB>3</SUB> structures. The (1−<I>x</I>)KNN–(<I>x</I>/5)NKLN composite ceramics displayed alloy effects with changing <I>x</I>. The NKLN phase was expected to be solidified into the KNN phase through the liquidus–solidus curve of the (1−<I>x</I>)KNN–(<I>x</I>/5)NKLN composite ceramics. The (1−<I>x</I>)KNN–(<I>x</I>/5)NKLN composite ceramics showed the ferroelectric distortions with orthorhombic symmetry. We discussed the ferroelectric and dielectric properties of the (1−<I>x</I>)KNN–(<I>x</I>/5)NKLN composite ceramics.</P>

Role of the Rapid Drink Challenge Test in Esophageal Motility Disorder Diagnosis

( Li-chang Hsing ),( Kee Wook Jung ) 대한소화기기능성질환·운동학회(구 대한소화관운동학회) 2020 Journal of Neurogastroenterology and Motility (JNM Vol.26 No.2

An improved procedure for generating standardised load-time histories for marine structures

Li, Shanshan,Cui, Weicheng,Paik, Jeom Kee SAGE Publications 2016 Proceedings of the Institution of Mechanical Engin Vol.230 No.2

<P>The load sequence effect has been proved from laboratory tests to be an influencing factor that cannot be neglected in the fatigue analysis of marine structures. To take account of this significant factor, fatigue life prediction should be based on fatigue crack propagation theory rather than the currently used cumulative fatigue damage theory. Accordingly, fatigue loading needs to be provided as the load-time history in the time domain rather than the load spectrum in the frequency domain. A general procedure for generating the standardised load-time history for marine structures based on a short-term load measurement has been proposed by the authors. This article seeks to further improve on this procedure and explain how to apply the determined standardised load-time history in the fatigue life prediction method based on the fatigue crack propagation theory. Finally, generation and application of a standardised load-time history are given for a tubular T-joint of an offshore platform, which demonstrates the practical and effective use of the proposed approach.</P>