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Effect of monovalent charge compensators on the photoluminescence properties of Ca_(3)(PO_(4))_(2):Tb^(3+),A^(+)(A=Li,Na,k)phosphors

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Journal of Materials Science & Technology 2021年第23期82卷 187-196页

作者： G.W.Jung k.park Faculty of Nanotechnology and Advanced Materials Engineering Sejong UniversitySeoul05006Republic of Korea

Ca_(3-x)(PO_(4))_(2):xTb^(3+)(0.2≤x≤0.4),Ca_(2.3)(PO_(4))_(2):0.35 Tb^(3+),0.35 A^(+)(A=Li,Na,k),and Ca_(2.3)(PO_(4))_(2):0.35 Tb^(3+),yLi^(+)(0.35≤y≤0.455)phosphors were prepared by solid-state *** the prepared phosphors formed a rhombohedral unit cell with the R3c space *** improve the photoluminescence(PL)properties of the Ca_(2.65)(PO_(4))_(2):0.35 Tb^(3+)phosphor,monovalent charge compensators such as Li^(+),NA^(+),and k^(+)were added to the Ca_(2.65)(PO_(4))_(2):0.35 Tb^(3+)*** charge compensators acted as fluxes,so they improved the *** excitation and emission properties were significantly improved through the incorporation of charge *** particular,among the charge compensators,Li^(+)ion substantially enhanced the emission intensity and color ***,considering the evaporation of Li_(2)CO_(3)during the annealing process,we optimized the concentration of Li^(+)charge compensator to enhance its PL ***,the green emission intensity of the Ca_(2.3)(PO_(4))_(2):0.35 Tb^(3+),0.385 Li^(+)phosphor was 260%higher than that of the Ca_(2.65)(PO_(4))_(2):0.35 Tb^(3+)*** believe that the effect of charge compensators on the PL properties and the optimum concentration of Li^(+)cha rge compensator are useful for the design of phosphors in light-emitting diodes.

关键词： Optical properties Ca_(3)(PO_(4))_(2) Emission Excitation Charge compensator

Enhanced thermoelectric performance of spark plasma sintered p-type Ca_(3-x)y_(x)Co_(4)O_(9+δ)systems

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Journal of Materials Science & Technology 2020年第20期52卷 212-222页

作者： J.S.Cha D.H.kim H.y.Hong k.park Faculty of Nanotechnology and Advanced Materials Engineering Sejong UniversitySeoul05006Republic of Korea

Highly textured dense Ca3-xyxCo4 O9+δ(0≤x≤0.3)samples were fabricated by combining sol-gel process with spark plasma sintering(SPS).y^3+substitution for Ca^2+simultaneously increased the Seebeck coefficient and reduced the thermal *** latter was attributed to the increase in lattice anharmonicity,structural distortion,and grain boundary area,which enhanced the phonon ***2.7y0.3Co4 O9+δshowed the largest dimensionless figure-of-merit(ZT=0.194)at 1073 k because it had the largest Seebeck coefficient and the lowest thermal *** ZT value was 55%larger than that of undoped Ca3 Co4 O9(0.125 at 1073 k).Therefore,y^3+substitution,sol-gel powder synthesis,and SPS are highly effective for enhancing the thermoelectric prope rties of Ca_(3)Co_(4)O_(9).

关键词： Electrical conductivity Ca_(3)Co_(4)O_(9) Thermoelectric properties Seebeck coefficient Thermal conductivity Spark plasma sintering

Photoluminescence enhancement of red-emitting GdVO_4:Eu and yVO_4:Eu phosphors by adding zinc

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Journal of Rare Earths 2013年第1期31卷 13-17页

作者： k.park J.kim k.y.kim J.y.kim y.kim S.J.Dhoble Faculty of Nanotechnology and Advanced Materials Engineering Sejong University Department of Advanced Materials Engineering Hoseo University Department of Chemistry and Institute of Basic Sciences Dankook University Department of Physics R.T.M. Nagpur University

We synthesized the rare-earth activated Ro.94_xEuo.06ZnxVO4 （R： Gd and y; 0〈_x〈_0.08） phosphors with a spherical mor- phology and a smooth surface by the ultrasonic spray pyrolysis. The annealed Ro.94_xEuo.06ZnxVO4 crystallized in the tetragonal zircon type structure, belonging to the space group of I41/amd. The incorporation of a small amount of Zn to Ro.94Euo.06VO4 improved the emission characteristics. The emission intensities of the Gdo.88EUo.06Zno.06VO4 and yo.9Euo.06Zno.04VO4 phosphors at 619 nm were 72% and 2 1% stronger than those of the Gdo,94Euo.06VO4 and yo.94Euo.06VO4 phosphors, respectively. We demonstrated that the addi- tion of Zn to Ro.94Euo.06VO4 was quite effective for improving the photoluminescent properties.

关键词： rare earths photolurninescence vanadate ultrasonic spray pyrolysis

Effect of Synthesis Method on Photoluminescence Properties of Na_2Sr_2Al_2PO_4Cl_9:Ce^(3+) Nanophosphor

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Nano-Micro Letters 2012年第2期4卷 78-82页

作者： k.N.Shinde S.J.Dhoble k.park N. S. Science and Arts College Department of Physics RTM Nagpur university Faculty of Nanotechnology and Advanced Materials Engineering Sejong University

We have synthesized a series of single-composition emission Na_2Sr_2Al_2PO_4Cl_9:Ce^(3+) phosphor by traditional solid state reactions and novel combustion method. Formation of compound was confirmed by X-ray diffraction analysis. The photoluminescence(PL) emission spectra were observed at 376 nm when excited around 322 nm for the various concentrations in both cases. The PL emission spectra of phosphors showed strong Ce^(3+)emission due to the 5d → 4f transition of Ce^(3+)ions. The Ce^(3+)emission intensity in Na_2Sr_2Al_2PO_4Cl_9:Ce^(3+) prepared by combustion was higher than that of solid state reactions.

关键词： Nanophosphor Luminescence Halophosphate

From capture to transport:A review of engineered surfaces for fog collection

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Droplet 2023年第2期2卷 46-68页

作者： youhua Jiang Christian Machado kyoo-Chul k.park Department of Mechanical Engineering Guangdong Technion—Israel Institute of TechnologyShantouChina Department of Mechanical Engineering Northwestern UniversityEvanstonIllinoisUSA

Collecting microscale water droplets suspended in the wind,that is,fog,using permeable surfaces is a promising solution to the worldwide problem of water scarcity and is of great interest to industries,such as mist elimination and recapturing water in cooling *** the past few decades,this topic has attracted a drastically increasing number of researchers across a wide range of ***,many aspects remain unclear,such as the definition and process of fog collection,fog collection determined from the perspectives of both the fog capture process and the liquid transport process,and how surface characteristics affect fog collection *** this review,we introduce and discuss fog collection from the perspectives of aerodynamics-governed fog-capturing processes and interfacial-phenomena-determined liquid transport ***,an emphasis is given to the design and engineering of permeable surfaces at different length scales to optimize the fog collection performance,including the dimension,morphology,and arrangement of wires at the millimetric scale,unidirectional spreading,and Laplace pressure gradient induced by asymmetric surface geometry and nano-/*** last,a brief outlook of future research directions is provided.

关键词： fog transport unidirectional

Apaf1 deletion rescues injury-induced neuronal death after optic nerve injury

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Apaf1 deletion rescues injury-induced neuronal death after o...

Microstructure and creep properties of Mg-4Al-2Sn-1(Ca,Sr) alloys

中国神经科学学会第九届全国学术会议暨第五次会员代表大会

作者： kevin k.park F.M.kirby Neurobiology Center Children’s Hospitaland Department of NeurologyHarvard Medical School300 Longwood AvenueBostonMA 02115USA

＜正＞In the adult mammals,axotomy of mature neurons in the central nervous system（CNS） triggers massive cell death and failure to spontaneous axon *** relationship between axotomy-induced neuronal death and axon regeneration has not yet well-understood,although promoting intrinsic capability of axon regeneration of CNS neurons is often accompanied by moderately improved neuronal *** we generated a mouse line with conditional knock-out of apoptotic protease activating factor 1（Apfal）.Apafl was deleted in retina ganglion cells （RGCs） by intravitreal injection of AAV-Cre virus,followed by optic nerve *** data show that although Apafl is deleted,RGCs have significantly a high survival rate,but their axon regeneration ability is not ***, axon regeneration is not the consequence of rescuing neuronal death.

关键词： Apaf1 conditional knock-out apoptosis axon regeneration

来源： cnki会议评论

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Transactions of Nonferrous Metals Society of China 2010年第7期20卷 1184-1191页

作者： B.H.kIM k.C.park y.H.park I.M.park Department of Material Science and Engineering Pusan National UniversitySan 30 Jangjeon-dongGeumjeong-guBusan 609-735Korea

The effects of Ca and Sr addition on the microstructure and creep properties of Mg-4Al-2Sn alloys were examined. Tensile tests at 25 ℃ and 200 ℃ and creep tests at 150 ℃ and 200 ℃ were carried out to estimate the room temperature and high temperature mechanical properties of these alloys. The microstrueture of the Mg-4Al-2Sn alloy showed dendritic a-Mg, Mg17Al12 and Mg2Sn phases. The latter two phases precipitated along the grain boundaries. The addition of Ca and Sr resulted in the formation of ternary CaMgSn and SrMgSn phases within the grain. The grain size was reduced slightly with the addition of Sr and Ca. The tensile strength was decreased by the addition of Ca and Sr at room temperature. However, the high temperature tensile strength was increased. The creep strength was improved by the addition of Ca and Sr.

关键词： magnesium alloys Ca Sr void initiation mechanical properties creep mechanism

Evaluation of microstructure and mechanical properties of Mg-xCe-0.5Zn alloys by nano-indentation

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Transactions of Nonferrous Metals Society of China 2010年第7期20卷 1240-1243页

作者： k.C.park B.H.kIM y.H.park I.M.park Department of Material Science and Engineering Pusan National UniversitySan 30 Jangjeon-dongGeumjeong-guBusan 609-735Korea

The microstructure and mechanical properties of Mg-xCe-0.5Zn （x=0.5, 1.5, 2.5, molar fraction, %） alloys were examined using a nano-indentation technique. The alloys were fabricated using a vacuum induction melting method under an argon atmosphere The microstruetures of Mg-xCe-0.5Zn alloys mainly consist ofa-Mg and eutectic Mg12Ce phase. The volume fraction and size of the eutectic Mgl2Ce phase increase with increasing Ce contents. Nano-indentation test results show that the indentation hardness and elastic modulus of the eutectic Mg12Ce phase are higher than those of the a-Mg matrix. In addition, the mean indentation hardness and elastic modulus of the Mg-xCe-0.5Zn alloys increase with the Ce addition amount increasing.

关键词： Mg alloys Mg-Ce-Zn rare earth microstructure mechanical properties nano-indentation

miR-21, miR-221 and miR-222 expression and prostate cancer recurrence among obese and non-obese cases

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Asian Journal of Andrology 2013年第2期15卷 226-230,I0007页

作者： Ernest k Amankwah Evelyn Anegbe Hyun park Julio Pow-Sang Ardeshir Hakam Jong y park Department of Cancer Epidemiology H. Lee Moffitt Cancer Center Tampa FL 33612 USA Department of G U Oncology H. Lee Moffitt Cancer Center Tampa FL 33612 USA Department of Anatomic Pathology H. Lee Moffitt Cancer Center Tampa FL 33612 USA

Recent evidence shows that certain microRNAs （miRNAs） play a role in both obesity and prostate cancer recurrence, but the association between the expression of these miRNAs and obesity in prostate cancer recurrence is unknown. In this study, we examined the effect of the interaction between obesity and miR-21, miR-221 or miR-222 expression on prostate cancer recurrence among 28 recurrent and 37 non-recurrent prostate cancer cases, miRNA expression was determined using quantitative real-time polymerase chain reaction. Cox proportional hazard models adjusting for age at diagnosis, clinical stage and Gleason score were used to estimate hazard ratios （HR） and 95% confidence intervals （95% CI） for recurrence free survival. A significantly （P=0.014） higher proportion of recurrent cases （78,6%） than non-recurrent cases （48.6%） had a low expression of miR-21 and the difference was more prominent in obese than non-obese patients. Multivariate analysis showed that the expression of miR-21 was an independent risk factor for recurrence in obese （HR=6.15, 95% CI= 1.04-36.48, P=-0.045）, but not in non-obese （HR= 1.28, 95% C1=0.30-5.49, P=0.74） cases. A significant association with recurrence was not observed for the expression of miR-221 and miR-222. In summary, our findings show that miR-21 is associated with prostate cancer recurrence after radical prostatectomy and suggest that the differential expression of miR-21 is more prominent in obese than in non-obese cases. Future larger studies are warranted to confirm these initial findings and to elucidate the mechanisms involved.

关键词： miR-21 miR-221 miR-222 miRNA obesity prostate carcinoma recurrence