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Broadband strong optical dichroism in topological Dirac semimetals with Fermi velocity anisotropy

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Chinese Physics B 2020年第7期29卷 128-134页

作者： j lim K j A Ooi C Zhang L K Ang Yee Sin Ang Science Math and TechnologySingapore University of Technology and DesignSingapore School of Energy and Chemical Engineering Xiamen University MalaysiaSelangor Darul Ehsan 43900Malaysia College of Chemistry and Chemical Engineering Xiamen UniversityXiamen 361005China School of Physics University of WollongongNorthfields AvenueNew South Wales 2522Australia

Prototypical three-dimensional(3D)topological Dirac semimetals(DSMs),such as Cd3As2 and Na3Bi,contain electrons that obey a linear momentum-energy dispersion with different Fermi velocities along the three orthogonal momentum *** being extensively studied in recent years,the inherent Fermi velocity anisotropy has often been neglected in the theoretical and numerical studies of 3D *** this omission does not qualitatively alter the physics of light-driven massless quasiparticles in 3D DSMs,it does quantitatively change the optical coefficients which can lead to nontrivial implications in terms of nanophotonics and plasmonics *** we study the linear optical response of 3D DSMs for general Fermi velocity values along each *** the signature conductivity-frequency scaling,σ(ω)∝ω,of 3D Dirac fermion is well-protected from the Fermi velocity anisotropy,the linear optical response exhibits strong linear dichroism as captured by the universal extinction ratio scaling law,Λi j=(vi/v j)^2(where i=j denotes the three spatial coordinates x,y,z,and vi is the i-direction Fermi velocity),which is independent of frequency,temperature,doping,and carrier scattering *** Cd3As2 and Na3Bi3,an exceptionally strong extinction ratio larger than 15 and covering a broad terahertz window is *** findings shed new light on the role of Fermi velocity anisotropy in the optical response of Dirac semimetals and open up novel polarization-sensitive functionalities,such as photodetection and light modulation.

关键词： topological Dirac semimetal optical anisotropy linear dichroismn linear response theory

NUMERICAL SIMULATIONS OF HYDRODYNAMIC BEHAVIORS IN CONICAL SPOUTED BEDS

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China Particuology 2006年第3期4卷 194-203页

作者： C. j. lim Fluidization Research Centre Department of Chemical and Biological Engineering University of British Columbia Vancouver BC V6T 1Z3 Canada

The axial and radial distributions of static pressures and vertical particle velocities of conical spouted beds have been simulated and compared with experimental data. Simulation results show that, among all factors investigated, the Actual Pressure Gradient （the APG term） in conical spouted beds, introduced as the default gravity term plus an empirical axial solid phase source term, has the most significant influence on static pressure profiles, followed by the restitution coefficient and frictional viscosity, while other factors almost have no effect. Apart from the solid bulk viscosity, almost all other factors affect the radial distribution of the axial particle velocity, although the influence of the APG term is less significant. For complex systems such as conical spouted beds where a fluidized spout region and a defluidized annulus region co-exist, the new term introduced in this work can improve the CFD simulation. Furthermore, for other systems with the Actual Pressure Gradient different from either fluidized beds or packed beds, the new approach can also be applied.

关键词： conical spouted bed hydrodynamics numerical simulation multiphase model

Real-world treatment attrition rates in advanced esophagogastric cancer

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World journal of Gastroenterology 2020年第39期26卷 6027-6036页

作者： Erica S Tsang Howard j lim Daniel j Renouf janine M Davies jonathan M Loree Sharlene Gill Department of Medicine BC CancerVancouver V5Z 4E6Canada Division of Medical Oncology University of British ColumbiaVancouver V5Z 4E6Canada

BACKGROUND Over the last decade,multiple agents have demonstrated efficacy for advanced esophagogastric cancer(EGC).Despite the availability of later lines of therapy,there remains limited real-world data about the treatment attrition rates between lines of *** To characterize the use and attrition rates between lines of therapy for patients with advanced *** We identified patients who received at least one cycle of chemotherapy for advanced EGC between july 1,2017 and july 31,2018 across six regional centers in British Columbia(BC),***,treatment,and outcomes data were *** Of 245 patients who received at least one line of therapy,median age was 66 years(IQR 58.2-72.3)and 186(76%)were male,Eastern Cooperative Oncology Group(ECOG)performance status 0/1(80%),gastric vs GEj(36%vs 64%).Histologies included adenocarcinoma(78%),squamous cell carcinoma(8%),and signet ring(14%),with 31%HER2 positive.72%presented with de novo disease,and 25%had received previous *** was a high level of treatment attrition,with patients receiving only one line of therapy n=122,50%),two lines n=83,34%),three lines n=34,14%),and four lines n=6,2%).Kaplan-Meier analysis demonstrated improved survival with increasing lines of therapy(median overall survival 7.7 vs 16.6 vs 22.8 vs 40.4 mo,P<0.05).On multivariable Cox regression,improved survival was associated with better baseline ECOG and increased lines of therapy(P<0.05).CONCLUSION The steep attrition rates between therapies highlight the unmet need for more efficacious early-line treatment options for patients with advanced EGC.

关键词： Esophagogastric cancer Gastric cancer Treatment attrition Systemic therapy Treatment outcomes Real-world evidence

Degradation of Synthetic Dyeing Wastewater by Underwater Electrical Discharge Processes

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Plasma Science and Technology 2013年第7期15卷 659-665页

作者： S.D.KIM D.I.jANG B.j.lim S.B.LEE Y.S.MOK Yeongsan River Environment Research Center National Institute of Environmental ResearchGwangju 500-480 Korea Department of Chemical and Biological Engineering Jeju National UniversityJeju 690-756 Korea

Electrical discharge treatments of synthetic dyeing wastewater were carried out with two different systems： underwater pulsed electrical discharge （UPED） and underwater dielectric barrier discharge （UDBD）. Reactive Blue 4 （RB4） and Acid Red 4 （AR4） were used as model contaminants for the synthetic wastewater. The performance of the aforementioned systems was compared with respect to the chromaticity removal and the energy requirement. The results showed that the present electrical discharge systems were very effective for degradation of the dyes. The dependences of the dye degradation rate on treatment time, initial dye concentration, electrical energy, and the type of working gas including air, 02, and N2 were examined. The change in the initial dye concentration did not largely affect the degradation of either RB4 or AR4. The energy delivered to the UPED system was only partially utilized for generating reactive species capable of degrading the dyes, leading to higher energy requirement than the UDBD system. Among the working gases, the best performance was observed with O2. As the degradation proceeded, the concentration of total dissolved solids and the solution conductivity kept increasing while pH showed a decreasing trend, revealing that the dyes were effectively mineralized.

关键词： degradation dyeing wastewater pulsed electrical discharge dielectric barrierdischarge

Machine learning of superconducting critical temperature from Eliashberg theory

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npj Computational Materials 2022年第1期8卷 113-120页

作者： S.R.Xie Y.Quan A.C.Hire B.Deng j.M.DeStefano I.Salinas U.S.Shah L.Fanfarillo j.lim j.Kim G.R.Stewart j.j.Hamlin P.j.Hirschfeld R.G.Hennig Department of Materials Science and Engineering University of FloridaGainesvilleFL32611USA Quantum Theory Project University of FloridaGainesvilleFL32611USA Department of Physics University of FloridaGainesvilleFL32611USA Scuola Internazionale Superiore di Studi Avanzati(SISSA) Via Bonomea 26534136TriesteItaly

The Eliashberg theory of superconductivity accounts for the fundamental physics of conventional superconductors,including the retardation of the interaction and the Coulomb pseudopotential,to predict the critical temperature T_(c).McMillan,Allen,and Dynes derived approximate closed-form expressions for the critical temperature within this theory,which depends on the electron–phonon spectral functionα^(2)F(ω).Here we show that modern machine-learning techniques can substantially improve these formulae,accounting for more general shapes of theα^(2)F *** symbolic regression and the SISSO framework,together with a database of artificially generatedα^(2)F functions and numerical solutions of the Eliashberg equations,we derive a formula for T_(c)that performs as well as Allen–Dynes for low-T_(c)superconductors and substantially better for higher-T_(c)*** corrects the systematic underestimation of Tc while reproducing the physical constraints originally outlined by Allen and *** equation should replace the Allen–Dynes formula for the prediction of higher-temperature superconductors.

关键词： function. critical theory

Critical Analysis of the Healthcare Response to Burn-Pit-Related Illnesses for Post-9/11 Iraq and Afghanistan Veterans

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Open journal of Emergency Medicine 2019年第2期7卷 17-27页

作者： Peter j. lim Ali R. Tayyeb Patricia A. Chin School of Nursing California State University Los Angeles CA USA

A serious concern among post-9/11 Iraq and Afghanistan veterans (IAV) are health conditions from military and environmental exposure while serving. Many veterans are becoming suddenly ill and experiencing symptoms that have been associated with exposure to burning trash or “burn pits” set up to destroy waste produced by the military. IAVs are exhibiting respiratory conditions and other numerous health issues from exposure to burn pits during deployments. From the US military operations to the Middle East, 70% of the military personnel reported respiratory illnesses, with 17% experiencing symptoms serious enough to require medical care. Despite growing concerns, little research has been conducted on the health conditions of returning veterans. Many veterans have difficulty gaining appropriate access to care, unable to travel long distances to Veterans health facility, or have to deal with long wait times to see a provider. As a result, many veterans utilize civilian emergency rooms and healthcare facilities. Most healthcare facilities are not familiar with military-related health conditions. To address and prevent delays in care, it is helpful to have a veteran-specific screener questionnaire at the point of healthcare access. Getting a better understanding of the background and history of veterans can aid in accurately triaging this community and lead to better health care outcomes. Collecting and maintaining data regarding health issues that can arise from burn pit exposures can help direct the care of this specific community of veterans. In seeking to improve the understanding of IAV health issues from exposure to burn pits, the aim of this article is to help educate and raise awareness, and assist health care professionals to better triage and direct the care or resources necessary to help this underserved and at-risk community of our veterans.

关键词： Veterans Burn Pit Screener

A Molecular Dynamics Approach for Optimizing Beam Intensities in IMPT Treatment Planning

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journal of Applied Mathematics and Physics 2019年第9期7卷 2130-2047页

作者： Li Liao Gino j. lim Xiaodong Zhang Department of Industrial Engineering University of Houston Houston TX USA Department of Radiation Physics The University of Texas MD Anderson Cancer Center Houston TX USA

This paper uses a molecular dynamics (MD) method for intensity-modulated proton therapy treatment planning optimization to overcome the problem of gradient-based optimization methods such as quasi-Newton, which is sensitive to starting conditions and is easily trapped in local minima. We implemented a molecular dynamics (MD) method and a quasi-Newton method for plan optimization. Three types of cancer cases, prostate, head-and-neck and lung cancer, were tested with three starting different initial conditions. Overall, the MD method consistently resulted in solutions with lower objective function values (OFVs) compared to those from the quasi-Newton algorithm. Furthermore, the MD method converged on the same OFV regardless of its initial starting points used for the prostate cancer case.

关键词： Molecular Dynamics Intensity-Modulated Proton Therapy Quasi-Newton

Direct ink writing of programmable functional silicone-based composites for 4D printing applications

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Interdisciplinary Materials 2022年第4期1卷 507-516页

作者： Zhiyang Lyu j.ustin Koh Gwendolyn j.H.lim Danwei Zhang Ting Xiong Lei Zhang Siqi Liu junfei Duan jun Ding john Wang jinlan Wang Yunfei Chen Chaobin He jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments School of Mechanical EngineeringSoutheast UniversityNanjingChina Department of Materials Science and Engineering National University of SingaporeSingaporeSingapore Agency for Science Technologyand Research(A*STAR)Institute of Materials Research and EngineeringSingaporeSingapore School of Materials Science and Engineering Changsha University of Science and TechnologyChangshaChina School of Physics Southeast UniversityNanjingChina

Polydimethylsiloxane(PDMS)has been widely used in flexible electronics,soft robotics,and ***,the fabrication of PDMS-based devices has mostly relied on conventional approaches,such as casting and molding,thereby limiting their *** we fabricate PDMS-based composites with programmable microstructures by direct ink writing and realize their practical functionalities of four-dimensional(4D)*** mechanical,thermomechanical and magnetic properties of the three-dimensional-printed composites can be well tailored by using carbon,metal,or ceramic functional *** taking advantage of the printable,flexible,and magnetic PDMS composites,we demonstrate new practical functionalities of 4D printing by designing programmable architectures,including magnetic-field-driven battery cases and patchworks,as well as arbitrary morphing ceramic *** particular,4D-printed batteries are constructed by PDMS-based battery cases for the first time,which can be actuated via external magnetic *** study broadens the paradigm of 4D printing for prospective applications,such as implant batteries,biomimetic engineering,and customized biomedical devices.

关键词： 4D printing 4D-printed batteries direct ink writing PDMS polymer-derived ceramics

Heat addition to fluidized bed membrane reactors for hydrogen production

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Heat addition to fluidized bed membrane reactors for hydroge...