Lanthanum zirconate based thermal barrier coatings: A review

Zhang, Jing,Guo, Xingye,Jung, Yeon-Gil,Li, Li,Knapp, James Elsevier Sequoia 2017 Surface & coatings technology Vol.323 No.-

<P><B>Abstract</B></P> <P>This review article summarizes the latest information about the manufacturing techniques of lanthanum zirconate (La<SUB>2</SUB>Zr<SUB>2</SUB>O<SUB>7</SUB>, LZ) powder and La<SUB>2</SUB>Zr<SUB>2</SUB>O<SUB>7</SUB> based thermal barrier coatings (TBCs). Lanthanum zirconate is a promising candidate material for TBC applications, due to its lower thermal conductivity and higher thermal stability compared to other traditional TBC systems. In this work, the physical, thermal, and mechanical properties of the powder and coatings are evaluated. The durability experiments of the TBCs in various thermal, mechanical, and corrosive conditions are also reviewed. In addition, theoretical studies on the powder and coatings properties are presented. Finally, future research directions of lanthanum zirconate as TBC applications are proposed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Comprehensive review of lanthanum zirconate (La<SUB>2</SUB>Zr<SUB>2</SUB>O<SUB>7</SUB>) based TBCs </LI> <LI> Complete summary of the physical, thermal, mechanical properties of La<SUB>2</SUB>Zr<SUB>2</SUB>O<SUB>7</SUB> </LI> <LI> Thermal cycling behavior and durability of La<SUB>2</SUB>Zr<SUB>2</SUB>O<SUB>7</SUB> TBCs is reviewed. </LI> <LI> Property and performance comparison between La<SUB>2</SUB>Zr<SUB>2</SUB>O<SUB>7</SUB> and YSZ based TBCs </LI> <LI> Modeling of La<SUB>2</SUB>Zr<SUB>2</SUB>O<SUB>7</SUB> is also reviewed. </LI> </UL> </P>

Ideal tensile strength and shear strength of ZrO₂(111)/Ni(111) ceramic-metal Interface: A first principle study

Guo, Xingye,Zhang, Yi,Jung, Yeon-Gil,Li, Li,Knapp, James,Zhang, Jing Elsevier 2016 Materials & Design Vol.112 No.-

<P><B>Abstract</B></P> <P>The ideal mechanical strengths of ZrO<SUB>2</SUB>(111)/Ni(111) ceramic-metal (C-M) interface are calculated through simulated tensile and shear deformations using the first principles calculations. The structures of ZrO<SUB>2</SUB>(111)/Ni(111) interfaces with 1- and 3-layer Ni thicknesses are optimized and the mechanical properties are investigated. For tensile deformation in [111] direction, the Young's moduli of the 1-layer Ni and 3-layer Ni M-C models are 139.9GPa and 60.2GPa, respectively; and ultimate tensile strengths are 11.6GPa and 7.9GPa, respectively. For shear deformation in {111} ⟨110⟩ system, the shear moduli of the 1-layer Ni and 3-layer Ni M-C models are 43.9GPa and 30.4GPa, respectively; and ultimate shear strengths are 7.0GPa and 3.0GPa, respectively. For shear deformation in {111} ⟨11 2 − ⟩ system, the shear moduli of the 1-layer Ni and 3-layer Ni M-C models are 30.9GPa and 17.3GPa, respectively; and ultimate shear strengths are 6.0GPa and 1.8GPa, respectively. Overall, 1-layer Ni C-M interface models have better mechanical properties than those of 3-layer models. The observed strengths are explained by using charge distribution, electron localization function, and Bader charge transfer analyses. The results are important for designing robust thermal barrier coating through optimizing bond coat thickness.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ideal tensile and shear strengths of ZrO2/Ni interface are calculated using DFT. </LI> <LI> Stress-strain curves of interfaces in tensile and shear deformations are calculated. </LI> <LI> 1-layer Ni interface models have higher mechanical strengths than 3-layer models. </LI> <LI> Charge density and Bader charge analyses are conducted to explain the strengths. </LI> </UL> </P> <P><B>Graphic abstract</B></P> <P>[DISPLAY OMISSION]</P>

Use of artificial intelligence in the management of T1 colorectal cancer: a new tool in the arsenal or is deep learning out of its depth?

James Weiquan Li,Lai Mun Wang,Katsuro Ichimasa,Kenneth Weicong Lin,James Chi-Yong Ngu,Tiing Leong Ang 대한소화기내시경학회 2024 Clinical Endoscopy Vol.57 No.1

The field of artificial intelligence is rapidly evolving, and there has been an interest in its use to predict the risk of lymph node metastasis in T1 colorectal cancer. Accurately predicting lymph node invasion may result in fewer patients undergoing unnecessary surgeries; conversely, inadequate assessments will result in suboptimal oncological outcomes. This narrative review aims to summarize the current literature on deep learning for predicting the probability of lymph node metastasis in T1 colorectal cancer, highlighting areas of potential application and barriers that may limit its generalizability and clinical utility.

Comparative Effectiveness of Laterally Placed Expandable versus Static Interbody Spacers: A 1-Year Follow-Up Radiographic and Clinical Outcomes Study

Li Yan Michael,Frisch Richard Francis,Huang Zheng,Towner James Edward,Li Yan Icy,Edsall Amber Lynn,Ledonio Charles 대한척추외과학회 2021 Asian Spine Journal Vol.15 No.1

Study Design: Retrospective chart review.Purpose: This study compared the clinical and radiographic outcomes of patients treated with expandable and static interbody spacers following minimally invasive lateral lumbar interbody fusion (MIS-LLIF) with 12-month follow-up.Overview of Literature: A common surgical option for the treatment of degenerative disk disease (DDD) is MIS-LLIF using static or expandable spacers to restore disk height (DH), neuroforaminal height (NH), and segmental lordosis. Static spacers may require excessive trialing and aggressive impaction, potentially leading to endplate disruption and subsidence. Expandable spacers allow for in situ expansion to help address complications associated with static spacers.Methods: This is an Institutional Review Board-exempt review of 69 patients (static, n=32; expandable, n=37) diagnosed with DDD who underwent MIS-LLIF at 1–2 contiguous level(s) using static or expandable spacers. Radiographic and clinical outcomes were collected and compared at pre- and postoperative time points up to 12 months.Results: The expandable group had a significantly higher mean change in Visual Analog Scale (VAS) scores at 6 weeks, 6 months, and 12 months vs. static (∆VAS at 12 months: expandable, 6.7±1.3; static, 5.1±2.6). Mean improvement of Oswestry Disability Index (ODI) scores at 3, 6, and 12 months were significantly better for the expandable group vs. static (∆ODI at 12 months: expandable, 63.2±13.2; static, 29.8±23.4). Mean DH and NH significantly increased at final follow-up for both groups, with no significant difference in DH improvement between groups. The expandable mean NH improvement at 6 weeks and 6 months was significantly greater vs. static. Segmental lordosis significantly improved in the expandable group at all time intervals vs static. Subsidence rate at 12 months was significantly lower in the expandable group (1/46, 2.2%) vs. static (12/37, 32.4%).Conclusions: Expandable spacers resulted in a significantly lower subsidence rate, improve segmental lordosis, and VAS and ODI outcomes at 12 months vs. static.

Numerical Modelling of Air-Water Flows over a Stepped Spillway with Chamfers and Cavity Blockages

Shicheng Li,James Yang,Qiulin Li 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.1

Owing to effective aeration and energy dissipation, a stepped spillway is commonly used in a roller-compacted concrete (RCC) dam. However, its complex air-water flow features are far from being fully understood. Roughness density, step and cavity shapes are essential parameters. Numerical simulations are carried out to investigate their effects on hydraulic properties. In combination with the realizable k-ε turbulence model, the two-phase Mixture Model is used. The results indicate higher air concentrations for the spillway with rounded steps than the ones with trapezoidal steps; the roughness density and cavity shape show no observable effects on the aeration performance with cavity blockages. The characteristic air-water velocity for the trapezoidal steps layout is larger than that for the rounded steps. However, neither layout is sensitive to the roughness density; the velocity results for trapezoidal cavity and rounded cavity cases are almost independent of the roughness density. The velocity for all cases exclusive of trapezoidal steps increase with an increase in roughness density. The min. and max. pressures on the trapezoidal steps are slightly larger than those on the rounded steps; they increase with an increasing roughness density. The cavity shape and roughness density do not evidently influence the extreme pressures. Compared with the conventional step layout, chamfering the step edges slightly enhance the energy dissipation; partially blocking the cavities do not lead to any substantial change. In addition, the energy loss is not clearly related to the roughness density and step edge/cavity shape.

Automated bone segmentation from dental CBCT images using patch-based sparse representation and convex optimization : Segmentation of CBCT image

Wang, Li,Chen, Ken Chung,Gao, Yaozong,Shi, Feng,Liao, Shu,Li, Gang,Shen, Steve G. F.,Yan, Jin,Lee, Philip K. M.,Chow, Ben,Liu, Nancy X.,Xia, James J.,Shen, Dinggang Published for the American Association of Physicis 2014 Medical physics Vol.41 No.4

<P>Cone-beam computed tomography (CBCT) is an increasingly utilized imaging modality for the diagnosis and treatment planning of the patients with craniomaxillofacial (CMF) deformities. Accurate segmentation of CBCT image is an essential step to generate three-dimensional (3D) models for the diagnosis and treatment planning of the patients with CMF deformities. However, due to the poor image quality, including very low signal-to-noise ratio and the widespread image artifacts such as noise, beam hardening, and inhomogeneity, it is challenging to segment the CBCT images. In this paper, the authors present a new automatic segmentation method to address these problems.</P>

Tailoring the Energy Landscape in Quasi-2D Halide Perovskites Enables Efficient Green-Light Emission

Quan, Li Na,Zhao, Yongbiao,Garcí,a de Arquer, F. Pelayo,Sabatini, Randy,Walters, Grant,Voznyy, Oleksandr,Comin, Riccardo,Li, Yiying,Fan, James Z.,Tan, Hairen,Pan, Jun,Yuan, Mingjian,Bakr, Osman American Chemical Society 2017 NANO LETTERS Vol.17 No.6

<P>Organo-metal halide perovskites are a promising platform for optoelectronic applications in view of their excellent charge-transport and bandgap tunability. However, their low photoluminescence quantum efficiencies, especially in low-excitation regimes, limit their efficiency for light emission. Consequently, perovskite light-emitting devices are operated under high injection, a regime under which the materials have so far been unstable. Here we show that, by concentrating photoexcited states into a small subpopulation of radiative domains, one can achieve a high quantum yield, even at low excitation intensities. We tailor the composition of quasi-2D perovskites to direct the energy transfer into the lowest-bandgap minority phase and to do so faster than it is lost to nonradiative centers. The new material exhibits 60% photoluminescence quantum yield at excitation intensities as low as 1.8 mW/cm(2), yielding a ratio of quantum yield to excitation intensity of 0.3 cm(2)/mW; this represents a decrease of 2 orders of magnitude in the excitation power required to reach high efficiency compared with the best prior reports. Using this strategy, we report light-emitting diodes with external quantum efficiencies of 7.4% and a high luminescence of 8400 cd/m(2).</P>

Estimating patient-specific and anatomically correct reference model for craniomaxillofacial deformity via sparse representation.

Wang, Li,Ren, Yi,Gao, Yaozong,Tang, Zhen,Chen, Ken-Chung,Li, Jianfu,Shen, Steve G F,Yan, Jin,Lee, Philip K M,Chow, Ben,Xia, James J,Shen, Dinggang Published for the American Association of Physicis 2015 Medical physics Vol.42 No.10

<P>A significant number of patients suffer from craniomaxillofacial (CMF) deformity and require CMF surgery in the United States. The success of CMF surgery depends on not only the surgical techniques but also an accurate surgical planning. However, surgical planning for CMF surgery is challenging due to the absence of a patient-specific reference model. Currently, the outcome of the surgery is often subjective and highly dependent on surgeon's experience. In this paper, the authors present an automatic method to estimate an anatomically correct reference shape of jaws for orthognathic surgery, a common type of CMF surgery.</P>

Automated segmentation of dental CBCT image with prior-guided sequential random forests : Automated segmentation of dental CBCT image

Wang, Li,Gao, Yaozong,Shi, Feng,Li, Gang,Chen, Ken-Chung,Tang, Zhen,Xia, James J.,Shen, Dinggang Published for the American Association of Physicis 2016 Medical physics Vol. No.

Characterization of PM_2.5-bound polycyclic aromatic hydrocarbons in Atlanta

Li, Zheng,Sjodin, Andreas,Porter, Erin N.,Patterson Jr., Donald G.,Needham Jr., Larry L.,Lee Jr., Sangil,Russell Jr., Armistead G.,Mulholland Jr., James A. Elsevier 2009 Atmospheric environment Vol.43 No.5

<P><B>Abstract</B></P><P>Twenty-four hour PM<SUB>2.5</SUB> samples from a rural site, an urban site, and a suburban site (next to a major highway) in the metropolitan Atlanta area in December 2003 and June 2004 were analyzed for 19 polycyclic aromatic hydrocarbons (PAH). Extraction of the air samples was conducted using an accelerated solvent extraction method followed by isotope dilution gas chromatography/mass spectrometry determination. Distinct seasonal variations were observed in total PAH concentration (i.e. significantly higher concentrations in December than in June). Mean concentrations for total particulate PAHs in December were 3.16, 4.13, and 3.40ngm<SUP>−3</SUP> for the urban, suburban and rural sites, respectively, compared with 0.60, 0.74, and 0.24ngm<SUP>−3</SUP> in June. Overall, the suburban site, which is impacted by a nearby major highway, had higher PAH concentration than did the urban site. Total PAH concentrations were found to be well correlated with PM<SUB>2.5</SUB>, organic carbon (OC), and elemental carbon (EC) in both months (<I>r</I><SUP>2</SUP>=0.36–0.78, <I>p</I><0.05), although the slopes from the two months were different. PAHs represented on average 0.006% of total PM<SUB>2.5</SUB> mass and 0.017% of OC in June, compared with 0.033% of total PM<SUB>2.5</SUB> and 0.14% of OC in December. Total PAH concentrations were also correlated with potassium ion (<I>r</I><SUP>2</SUP>=0.39, <I>p</I>=0.014) in December, but not in June, suggesting that in winter biomass burning can potentially be an important source for particulate PAH. Retene was found at a higher median air concentration at the rural site than at the urban and suburban sites—unlike the rest of the PAHs, which were found at lower levels at the rural site. Retene also had a larger seasonal difference and had the weakest correlation with the rest of the PAHs measured, suggesting that retene, in particular, might be associated with biomass burning.</P>