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Hardness of Porous Nanocrystalline Co-Ni Electrodeposits
C. Ma,S. C. Wang,R. J. K. Wood,J. Zekonyte,Q. Luo,F. C. Walsh 대한금속·재료학회 2013 METALS AND MATERIALS International Vol.19 No.6
The Hall-Petch relationship can fail when the grain size is below a critical value of tens of nanometres. This occurs particularly for coatings having porous surfaces. In this study, electrodeposited nanostructured Co-Ni coatings from four different nickel electroplating baths having grain sizes in the range of 11-23 nm have been investigated. The finest grain size, approximately 11 nm, was obtained from a coating developed from the nickel sulphate bath. The Co-Ni coatings have a mixed face centred cubic and hexagonal close-packed structures with varying surface morphologies and different porosities. A cluster-pore mixture model has been proposed by considering no contribution from pores to the hardness. As the porosity effect was taken into consideration, the calculated pore-free hardness is in agreement with the ordinary Hall- Petch relationship even when the grain size is reduced to 11 nm for the Co-Ni coatings with 77±2 at% cobalt. The present model was applied to other porous nanocrystalline coatings, and the Hall-Petch relationship was maintained.
C. S. Yang,K. F. Chien,J. Y. Lai,C. W. Luo,W. C. Chou,Y. T. Shih,J. S. Wang,S. R. Jian 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5
Self-assembled CdTe/ZnSe Stranski-Krastanow quantum-dot (QD) structures, which have a CdSe-like precursor-layer (PCL) between CdTe quantum dots and ZnSe matrix, were grown by molecular beam epitaxy. The carrier dynamics of the structures was studied by photoluminescence (PL) and time-resolved photoluminescence (TRPL) measurements. The temperature-dependent PL spectra revealed that there is a carrier transformation from small dots to larger dots via the precursor layer. Temperature-dependent PL measurements verify the existence of the QD excited excitonic state in 5.0 mono-layer (ML) coverage. In 0.6 ML coverage, the TRPL spectra exhibited a double-exponential decay process, as the detection energy at PCL emission energy. The faster decay time is corresponded to the carrier lifetime in PCL, the slower decay time exhibits the carrier in small QD. However, in 5.0 ML coverage, a faster and slower decay time represents the carrier lifetime in QD excited state for larger QD and the carrier lifetime in QD ground state for smaller QD.
Porous Al2O3 catalyst carrier by 3D additive manufacturing for syngas reforming
N.C. Fan,Y.Y. Chen,K.Y. Chen,W.C.J. Wei,B. H. Liu,A.B. Wang,R. C. Luo 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.9
A disk-shaped ceramic catalyst made by 3D printing (3DP) is used to reform syngas. We select two Al2O3 powders (α- andhigh-surface-area θ-Al2O3) and polymeric binders for preparing the 3DP feedstock. Catalyst stacked Al2O3 disks are made bykneading the polymers with ceramic powders and extruding to produce filaments, which are melted and used for 3D additivemanufacturing (AM). The processing parameters (sequence of addition, viscosity of the feedstock, etc.), the phasetransformation of the θ-powder, and catalytic properties of the made carrier are examined. The made alumina disks weredensified to a relative density (RD) of 40% −65%. Two porous disks were coated with catalyst NiO and CeO2, and used toreform syngas made from waste paper. The best case reforms the CH4 content in the syngas from 25.7% down to 0.15% orlower. The reformed gaseous fuel is suitable for solid oxide fuel cells (SOFCs).
Abernathy, C.R.,Gila, B.P.,Onstine, A.H.,Pearton, S.J.,Kim, Ji-Hyun,Luo, B.,Mehandru, R.,Ren, F.,Gillespie, J.K.,Fitch, R.C.,Seweel, J.,Dettmer, R.,Via, G.D.,Crespo, A.,Jenkins, T.J.,Irokawa, Y. The Institute of Electronics and Information Engin 2003 Journal of semiconductor technology and science Vol.3 No.1
Both MgO and $Sc_2O_3$ are shown to provide low interface state densities (in the $10^{11}{\;}eV^{-1}{\;}cm{\;}^{-2}$ range)on n-and p-GaN, making them useful for gate dielectrics for metal-oxide semiconductor(MOS) devices and also as surface passivation layers to mitigate current collapse in GaN/AlGaN high electron mobility transistors(HEMTs).Clear evidence of inversion has been demonstrated in gate-controlled MOS p-GaN diodes using both types of oxide. Charge pumping measurements on diodes undergoing a high temperature implant activation anneal show a total surface state density of $~3{\;}{\times}{\;}10^{12}{\;}cm^{-2}$. On HEMT structures, both oxides provide effective passivation of surface states and these devices show improved output power. The MgO/GaN structures are also found to be quite radiation-resistant, making them attractive for satellite and terrestrial communication systems requiring a high tolerance to high energy(40MeV) protons.
Graphene oxide based conductive glue as a binder for ultracapacitor electrodes
Luo, Jiayan,Tung, Vincent C.,Koltonow, Andrew R.,Jang, Hee Dong,Huang, Jiaxing The Royal Society of Chemistry 2012 Journal of materials chemistry Vol.22 No.26
<P>An adhesive and conductive glue was created by synergistic assembly of graphene oxide (GO), single walled carbon nanotubes (SWCNTs) and conjugate polymer PEDOT:PSS in aqueous solution. The GO–SWCNTs–PEDOT:PSS glue can be used as a binder to fabricate metal oxide nanoparticle based ultracapacitors. Since the functional nanoparticles are immersed in this conductive gel, uniform electrical and mechanical interconnect can be achieved, leading to enhanced performance of ultracapacitors.</P> <P>Graphic Abstract</P><P>Synergistic assembly of GO, SWCNTs and PEDOT:PSS creates a sticky and conductive glue as an effective binder for ultracapacitors. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2jm30819c'> </P>
Cao, C.,Luo, Z.,Guo, S.,Cao, R.,Noh, H.M.,Jeong, J.H.,Xie, A. Pergamon 2014 Spectrochimica acta. Part A, Molecular and biomole Vol.133 No.-
<P>Through a solid-state reaction method, the Ce3+/Tb3+ co-doped MyGdFx (M = Li, Na, K; x = 3, 4, 6; y = 0, 1, 3) system samples have been synthesized by controlling the annealing temperatures and the ratios of raw materials. The samples were characterized by X-ray diffraction (XRD) patterns, photoluminescence (PL) excitation and emission spectra as well as luminescent dynamic decay curves. The experimental results suggest that the LiF is more difficult to react with the prepared material compared that of NaF or KF under similar reaction conditions. The samples crystallized in different crystalline phases. The energy transfer from Ce3+ to Tb3+ or Ce3+ to Gd3+ to Tb3+ has been observed in all the samples. The Ce3+ and Tb3+ present different optical properties for they are sensitive to the local environment. In addition, the deduced lifetime of Tb3+ D-5(4) -> F-7(5) transition decreases in the same system samples with the annealing temperature increasing. The deduced lifetime of Tb3+ D-5(4) -> F-7(5) also decreases with the increase of the KF concentration in the KF system samples. (C) 2014 Elsevier B.V. All rights reserved.</P>
Jessica Luo,Whitney D. Moss,Giovanna R. Pires,Irfan A. Rhemtulla,Megan Rosales,Gregory J. Stoddard,Jayant P. Agarwal,Alvin C. Kwok 대한성형외과학회 2022 Archives of Plastic Surgery Vol.49 No.6
Background In March 2021, the United States Food and Drug Administration (FDA) safety communication cautioned against the use of acellular dermal matrix (ADM) products in breast reconstruction and reiterated that the FDA does not approve ADM use in breast surgery. This study aims to assess the safety of ADM use in breast reconstruction. Methods Women who underwent ADM and non-ADM assisted tissue expander (TE)- based breast reconstruction were identified using the National Surgical Quality Improvement Program database (2012–2019). Trends of ADM use over time, and 30-day outcomes of surgical site infection (SSI), dehiscence, and unplanned reoperation were assessed. Results Of the 49,049 TE-based breast reconstructive cases, 42.4% were ADM assisted and 57.6% non-ADM assisted. From 2012 to 2019, the use of ADM increased from 26.1 to 55.6% (relative risk [RR] ¼1.10; p<0.01). Higher rates of SSI (3.9 vs. 3.4%; p¼0.003) and reoperation (7.4 vs. 6.0%; p<0.001) were seen in the ADM cohort. There was no significant difference seen in dehiscence rates (0.7 vs. 0.7%; p¼0.73). The most common reoperation within 30 days for the ADM group (17.6%) was removal of TE without insertion of implant (current procedural terminology: 11,971). ADM-assisted breast reconstruction was associated with increased relative risk of SSI by 10% (RR¼1.10, confidence interval [CI]: 1.01–1.21; p¼0.03) and reoperation by 15% (RR¼1.15, CI: 1.08–1.23; p<0.001). Conclusions ADM-assisted breast reconstruction more than doubled from 2012 to 2019. There are statistically higher complication rates of SSI (0.5%) and reoperation (1.4%) with ADM use in TE-based breast reconstruction, suggesting that reconstruction without ADM is safe when comparing immediate postoperative outcomes.
Interface control of bulk ferroelectric polarization.
Yu, P,Luo, W,Yi, D,Zhang, J X,Rossell, M D,Yang, C-H,You, L,Singh-Bhalla, G,Yang, S Y,He, Q,Ramasse, Q M,Erni, R,Martin, L W,Chu, Y H,Pantelides, S T,Pennycook, S J,Ramesh, R National Academy of Sciences 2012 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.109 No.25
<P>The control of material interfaces at the atomic level has led to novel interfacial properties and functionalities. In particular, the study of polar discontinuities at interfaces between complex oxides lies at the frontier of modern condensed matter research. Here we employ a combination of experimental measurements and theoretical calculations to demonstrate the control of a bulk property, namely ferroelectric polarization, of a heteroepitaxial bilayer by precise atomic-scale interface engineering. More specifically, the control is achieved by exploiting the interfacial valence mismatch to influence the electrostatic potential step across the interface, which manifests itself as the biased-voltage in ferroelectric hysteresis loops and determines the ferroelectric state. A broad study of diverse systems comprising different ferroelectrics and conducting perovskite underlayers extends the generality of this phenomenon.</P>