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Rapid synthesis of transition metal dichalcogenide-carbon aerogel composites for supercapacitor electrodes

Microsystems & Nanoengineering 2017年第1期3卷 212-220页

作者： matthew J.Crane matthew b.lim Xuezhe Zhou Peter J.Pauzauskie Department of Chemical Engineering University of WashingtonSeattleWA 98195-1750USA Department of Materials Science&Engineering University of WashingtonSeattleWA 98195-2120USA Fundamental&Computational Sciences Directorate Pacific Northwest National LaboratoryRichlandWA 99352USA

Transition metal dichalcogenide(TMD)materials have recently demonstrated exceptional supercapacitor properties after conversion to a metallic phase,which increases the conductivity of the ***,freestanding,exfoliated transition metal dichalcogenide films exhibit surface areas far below their theoretical maximum(1.2%),can fail during electrochemical operation due to poor mechanical properties,and often require pyrophoric chemicals to *** the other hand,pyrolyzed carbon aerogels exhibit extraordinary specific surface areas for double layer capacitance,high conductivity,and a strong mechanical network of covalent chemical *** this paper,we demonstrate the scalable,rapid nanomanufacturing of TMD(MoS2 and WS2)and carbon aerogel composites,favoring liquid-phase exfoliation to avoid pyrophoric *** aerogel matrix support enhances conductivity of the composite and the synthesis can complete in 30 *** find that the addition of transition metal dichalcogenides does not impact the structure of the aerogel,which maintains a high specific surface area up to 620 m^(2) g−1 with peak pore radii of 10 *** supercapacitor tests of the aerogels yield capacitances around 80 F g^(−1) at the lowest applied currents,the aerogels loaded with TMD’s exhibit volumetric capacitances up to 127% greater than the unloaded *** addition,the WS2 aerogels show excellent cycling stability with no capacitance loss over 2000 cycles,as well as markedly better rate capability and lower charge transfer resistance compared to their MoS2-loaded *** hypothesize that these differences in performance stem from differences in contact resistance and in the favorability of ion adsorption on the chalcogenides.

关键词： aerogel molybdenum disulfide nanomanufacturing rapid resorcinol-formaldehyde supercapacitor transition metal dichalcogenide tungsten disulfide

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Novel genes involved in vascular dysfunction of the middle temporal gyrus in Alzheimer's disease:transcriptomics combined with machine learning analysis

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Neural Regeneration Research 2025年第12期20卷 3620-3634页

作者： Meiling Wang Aojie He Yubing Kang Zhaojun Wang Yahui He Kahleong lim Chengwu Zhang Li Lu School of basic Medical Sciences Shanxi Medical UniversityTaiyuanShanxi ProvinceChina Lee Kong Chian School of Medicine Nanyang Technological UniversitySingaporeSingapore Precise Diagnosis and Treatment Center for Neurodegenerative Diseases Shanxi Medical UniversityTaiyuanShanxi ProvinceChina

Studies have shown that vascular dysfunction is closely related to the pathogenesis of Alzheimer's *** middle temporal gyrus region of the brain is susceptible to pronounced impairment in Alzheimer's *** of the molecules involved in vascular aberrance of the middle temporal gyrus would support elucidation of the mechanisms underlying Alzheimer's disease and discove ry of novel targets for *** carried out single-cell transcriptomic analysis of the middle temporal gyrus in the brains of patients with Alzheimer's disease and healthy controls,revealing obvious changes in vascular *** analysis of intercellular communication in the middle temporal gyrus showed that the number of cell interactions in this region was decreased in Alzheimer's disease patients,with altered intercellular communication of endothelial cells and pericytes being the most *** expressed genes were also *** the CellChat results,AUCell evaluation of the pathway activity of specific cells showed that the obvious changes in vascular function in the middle temporal gyrus in Alzheimer's disease were directly related to changes in the vascular endothelial growth factor(VEGF)A-VEGF receptor(VEGFR)2 *** analysis identified subtypes of endothelial cells and pericytes directly related to VEGFA-VEGFR2 pathway *** subtypes of middle temporal gyrus cells showed significant alteration in AD:endothelial cells with high expression of Erb-b2 receptor tyrosine kinase 4(ERbb4^(high))and pericytes with high expression of angiopoietin-like 4(ANGPTL4^(high)).Finally,combining bulk RNA sequencing data and two machine learning algorithms(least absolute shrinkage and selection operator and random forest),four characteristic Alzheimer's disease feature genes were identified:somatostatin(SST),protein tyrosine phosphatase non-receptor type 3(PTPN3),glutinase(GL3),and tropomyosin 3(PTM3).These genes were downregulated in th

关键词： Alzheimer’s disease bioinformatics CellChat cerebrovascular disorders endothelial cells intercellular communication machine learning middle temporal gyrus pericytes vascular endothelial growth factor pathway

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Tbit/s line-rate satellite feeder links enabled by coherent modulation and full-adaptive optics

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Light(Science & Applications) 2023年第9期12卷 1727-1738页

作者： Yannik Horst bertold Ian bitachon Laurenz Kulmer Jannik brun Tobias blatter Jean-Marc Conan Aurélie Montmerle-bonnefois Joseph Montri béatrice Sorrente Caroline b.lim Nicolas Védrenne Daniel Matter Loann Pommarel benedikt baeuerle Juerg Leuthold ETH Zurich Institute of Electromagnetic Fields(IEF)Gloriastrasse 358092 ZürichSwitzerland ONERA DOTAParis Saclay UniversityF-92322 ChâtillonFrance Thales Alenia Space in Switzerland Schaffhauserstrasse 5808052 ZürichSwitzerland Polariton Technologies AG 8803 RüschlikonSwitzerland Present address:Currently with LNE-SYRTE Observatoire de ParisParisFrance

Free-space optical(FSO)communication technologies constitute a solution to cope with the bandwidth demand of future satellite-ground *** may overcome the RF bottleneck and attain data rates in the order of Tbit/s with only a handful of ground ***,we demonstrate single-carrier Tbit/s line-rate transmission over a free-space channel of 53.42 km between the Jungfraujoch mountain top(3700 m)in the Swiss Alps and the Zimmerwald Observatory(895 m)near the city of bern,achieving net-rates of up to 0.94 Tbit/*** this scenario a satellite-ground feeder link is mimicked under turbulent *** adverse conditions high throughput was achieved by employing a full adaptive optics system to correct the distorted wavefront of the channel and by using polarization-multiplexed high-order complex modulation *** was found that adaptive optics does not distort the reception of coherent modulation ***,we introduce constellation modulation–a new four-dimensional bPSK(4D-bPSK)modulation format as a technique to transmit high data rates under lowest *** way we show 53 km FSO transmission of 13.3 Gbit/s and 210 Gbit/s with as little as 4.3 and 7.8 photons per bit,respectively,at a bit-error ratio of 1∙10−*** experiments show that advanced coherent modulation coding in combination with full adaptive optical filtering are proper means to make next-generation Tbit/s satellite communications practical.

关键词： Tbit/s Gbit/s polarization

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Analysis of non-symmetrical flapping airfoils

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Acta Mechanica Sinica 2009年第4期25卷 433-450页

作者： W.b.Tay K.b.lim Department of Mechanical Engineering National University of Singapore

Simulations have been done to assess the lift, thrust and propulsive efficiency of different types of non-symmetrical airfoils under different flapping configurations. The variables involved are reduced frequency, Strouhal number, pitch amplitude and phase angle. In order to analyze the variables more efficiently, the design of experiments using the response surface methodology is applied. Results show that both the variables and shape of the airfoil have a profound effect on the lift, thrust, and efficiency. by using non- symmetrical airfoils, average lift coefficient as high as 2.23 can be obtained. The average thrust coefficient and efficiency also reach high values of 2.53 and 0.61, respectively. The lift production is highly dependent on the airfoil＇s shape while thrust production is influenced more heavily by the variables. Efficiency falls somewhere in between. Two-factor interac- tions are found to exist among the variables. This shows that it is not sufficient to analyze each variable individually. Vorticity diagrams are analyzed to explain the results obtained. Overall, the S1020 airfoil is able to provide relatively good efficiency and at the same time generate high thrust and lift force. These results aid in the design of a better ornithopter＇s wing.

关键词： Flapping Non-symmetrical Design ofexperiments Ornithopter Airfoil

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Numerical analysis of the s1020 airfoils in tandem under different flapping configurations

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Acta Mechanica Sinica 2010年第2期26卷 191-207页

作者： K.b.lim W.b.Tay Department of Mechanical Engineering National University of Singapore21 Lower Kent Ridge RoadSingapore 119077Singapore

The objective of this project is to improve the performance of the efficiency, thrust and lift of flapping wings in tandem arrangement. This research investigates the effect of the arrangement of the airfoils in tandem on the performance of the airfoils by varying the phase difference and distance between the airfoils. Three flapping configurations from an earlier phase of a research which gives high efficiency, thrust and lift are used in the tandem simulation. It is found all the different flapping configurations show improvement in the efficiency, thrust or lift when the distance between the two airfoils and the phase angle between the heaving positions of the two airfoils are optimal. The average thrust coefficient of the tandem arrangement managed to attain more than twice that of the single one （4.84 vs. 2.05）. On the other hand, the average lift coefficient of the tandem arrangement also increased to 4.59, as compared to the original single airfoil value of 3.04. All these results obtained will aid in the design of a better ornithopter with tandem wing arrangement.

关键词： Tandem Flapping· Airfoils Ornithopter·Immersed boundary

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High-fidelity optical diffraction tomography of multiple scattering samples

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Light(Science & Applications) 2019年第1期8卷 454-465页

作者： Joowon lim Ahmed b.Ayoub Elizabeth E.Antoine Demetri Psaltis Ecole Polytechnique Federale de Lausanne Optics LaboratoryCH-1015 LausanneSwitzerland

We propose an iterative reconstruction scheme for optical diffraction tomography that exploits the split-step nonparaxial(SSNP)method as the forward model in a learning tomography *** with the beam propagation method(bPM)previously used in learning tomography(LT-bPM),the improved accuracy of SSNP maximizes the information retrieved from measurements,relying less on prior assumptions about the sample.A rigorous evaluation of learning tomography based on SSNP(LT-SSNP)using both synthetic and experimental measurements confirms its superior performance compared with that of the *** from the accuracy of SSNP,LT-SSNP can clearly resolve structures that are highly distorted in the LT-bPM.A serious limitation for quantifying the reconstruction accuracy for biological samples is that the ground truth is *** overcome this limitation,we describe a novel method that allows us to compare the performances of different reconstruction schemes by using the discrete dipole approximation to generate synthetic ***,we explore the capacity of learning approaches to enable data compression by reducing the number of scanning angles,which is of particular interest in minimizing the measurement time.

关键词： scattering optical diffraction

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Unique and conserved features of floral evocation in legumes

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Journal of Integrative Plant biology 2014年第8期56卷 714-728页

作者： lim Chee Liew Mohan b. Singh Prem L. bhalla Plant Molecular biology and biotechnology Laboratory Melbourne School of Land and Environment University of Melbourne

Legumes, with their unique ability to fix atmo- spheric nitrogen, play a vital role in ensuring future food security and mitigating the effects of climate change because they use less fossil energy and produce less greenhouse gases compared with N-fertilized systems. Grain legumes are second only to cereal crops as a source of human and animal food, and they contribute approximately one third of the protein consumed by the human population. The productivityof seed crops, such as grain legumes, is dependent on flowering. Despite the genetic variation and importance of flowering in legume production, studies of the molecular pathways that control flowering in legumes are limited. Recent advances in genomics have revealed that legume flowering pathways are divergent from those of such model species as Arabidopsis thaliana. Here, we discuss the current understanding of flowering time regulation in legumes and highlight the unique and conserved features of floral evocation in legumes.

关键词： Flowering legume soybean

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AnAdaptive Moving Mesh Method for Two-Dimensional Incompressible Viscous Flows

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Communications in Computational Physics 2008年第3期3卷 679-703页

作者： Zhijun Tan K.M.lim b.C.Khoo Singapore-MIT Alliance 4 Engineering Drive 3National University of SingaporeSingapore 117576Singapore Department of Mechanical Engineering National University of Singapore10 Kent Ridge CrescentSingapore 119260Singapore.

In this paper, we present an adaptive moving mesh technique for solvingthe incompressible viscous flows using the vorticity stream-function formulation. Themoving mesh strategy is based on the approach proposed by Li et al. [J. Comput. Phys.,170 (2001), pp. 562–588] to separate the mesh-moving and evolving PDE at each timestep. The Navier-Stokes equations are solved in the vorticity stream-function form bya finite-volume method in space, and the mesh-moving part is realized by solving theEuler-Lagrange equations to minimize a certain variation in conjunction with a moresophisticated monitor function. A conservative interpolation is used to redistributethe numerical solutions on the new meshes. This paper discusses the implementationof the periodic boundary conditions, where the physical domain is allowed to deformwith time while the computational domain remains fixed and regular throughout. Numericalresults demonstrate the accuracy and effectiveness of the proposed algorithm.

关键词： Moving mesh method finite volume method Navier-Stokes equations vorticity stream-function incompressible flow.

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An Implementation ofMAC Grid-based IIM-Stokes Solver for Incompressible Two-Phase Flows

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Communications in Computational Physics 2011年第10期10卷 1333-1362页

作者： Zhijun Tan K.M.lim b.C.Khoo Guangdong Province Key Laboratory of Computational Science and School of Mathematics and Computational Science Sun Yat-sen UniversityGuangzhou 510275China Singapore-MIT Alliance 4 Engineering Drive 3National University of SingaporeSingapore 117576Singapore Department ofMechanical Engineering National University of Singapore10 Kent Ridge CrescentSingapore 119260Singapore

*** this paper,a novel implementation of immersed interface method combined with Stokes solver on a MAC staggered grid for solving the steady two-fluid Stokes equations with *** velocity components along the interface are introduced as two augmented variables and the resulting augmented equation is then solved by the GMRES *** augmented variables and/or the forces are related to the jumps in pressure and the jumps in the derivatives of both pressure and velocity,and are interpolated using cubic splines and are then applied to the fluid through the jump *** Stokes equations are discretized on a staggered Cartesian grid via a second order finite difference method and solved by the conjugate gradient *** numerical results show that the overall scheme is second order *** major advantages of the present IIM-Stokes solver are the efficiency and flexibility in terms of types of fluid flow and different boundary *** proposed method avoids solution of the pressure Poisson equation,and comparisons are made to show the advantages of time savings by the present *** generalized two-phase Stokes solver with correction terms has also been applied to incompressible two-phase Navier-Stokes flow.

关键词： Incompressible two-phase Stokes equations two-phaseNavier-Stokes equations discontinuous viscosity singular force immersed interface method Uzawa method front tracking method.

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Phase Formation and Magnetic Properties of Nanocomposite Nd-Fe-b Adjusted by Small Amount of Dy and Co

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Journal of Rare Earths 2004年第Z2期22卷 89-94页

作者： T S Jang T W lim H S Aum D H Lee M b Kim Division of Materials and Chemical Engineering Sun Moon UniversityKorea Division of Materials and Chemical EngineeringSun Moon UniversityKorea Division of Mechanical EngineeringSun Moon University 100 Kalsan LiTangjung MyonAsan CityChoongnam 336-708Korea Division of Materials and Chemical EngineeringSun Moon UniversityKorea Division of Materials and Chemical EngineeringSun Moon UniversityKorea

In order to improve and stabilize the magnetic properties of nanocomposite Nd2Fe14b/α-Fe magnetic alloys by a compositional adjustment, small amount of Dy and/or Co was added to Nd9Fe84b7 alloys. DTA analysis on the amorphous of the alloys took place as the soft magnetic phases were crystallized, and then the hard magnetic Nd2Fe14b was precipitated from them. While α-Fe and a metastable 1:7 (TbCu7-type) phase were formed simultaneously in Dy and Co-free alloys, they were crystallized separately at different temperatures after Dy or Co was added. This phase separation occurred more clearly in the Dy-treated alloys and the other soft magnetic phase Fe3b was also stabilized by Dy and/or Co. The 1: 7 phase that was stabilized by Dy and/or Co was not eliminated at 700 ℃, decreasing magnetic properties of the alloys. It was eventually disappeared above 725 ℃, but Fe3b was not eliminated even at 750 ℃ when Dy was added more than 0.5 at% or Co was added more than 2.0 at%. Amount of Nd2Fe14b in the alloys tended to increase as Dy addition increased,whereas Co addition did not lead to any appreciable change in the ratio of α-Fe and Nd2Fe14b. Moreover, Dy addition apparently increased coercivity of an alloy while Co addition had a beneficial effect on remanence. The grains in the Dytreated alloys were usually finer than those in the Co-treated alloys. The grain size of both α-Fe and Nd2Fe14b in the alloys exhibiting mr ≥ 0.72 was in the range of 20 ～ 40 nm or even larger 50 nm, which is larger than the theoretical optimum size ( ～ 10 nm). Typical magnetic properties obtained from a Nd7.5Dy1.5Fe82.5Co1.5b7 alloy annealed for 12 min at 725 ℃were iHc=4.85 kOe, br= 11.32 kG, (bH)max = 15.73 MGOe, and mr=0.73.

关键词： nanocomposite Nd-Fe-b magnetic properties remanence coercivity

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