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Compact prototype microfabricated gas chromatographic analyzer for autonomous determinations of VOC mixtures at typical workplace concentrations

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Microsystems & Nanoengineering 2018年第1期4卷 390-399页

作者： Junqi Wang Jonathan Bryant-Genevier Nicolas Nuñovero Chengyi Zhang Bruce Kraay Changhua Zhan Kee Scholten Robert Nidetz Sanketh Buggaveeti Edward T.Zellers Department of Chemistry University of MichiganAnn ArborMI 48109USA Department of Environmental Health Sciences University of MichiganAnn ArborMI 48109USA Applied Physics Program University of MichiganAnn ArborMI 48109USA Department of Mechanical Engineering University of MichiganAnn ArborMI 48109USA Center for Wireless Integrated MicroSensing and Systems University of MichiganAnn ArborMI 48109USA

This report concerns a benchtop prototype instrument containing a gas chromatographic microanalytical system(μGC)designed for the selective determination of multiple airborne volatile organic compounds(VOCs)at concentrations in the vicinity of recommended occupational exposure *** core microsystem consists of a set of discrete Si-microfabricated devices:a dualcavity,adsorbent-packed micro-preconcentrator-focuser(μPCF)chip that quantitatively captures and thermally desorbs/injects VOCs with vapor pressures between~0.03 and 13 kPa;tandem micro-column(μcolumn)chips with cross-linked PDMS wall-coated stationary phases capable of temperature-programmed separations;and an integrated array of fiveμchemiresistors(μCR)coated with different thiolate-monolayer protected gold nanoparticle(MPN)interface films that quantifies and further differentiates among the analytes by virtue of the response patterns *** key components include a pre-trap for low-volatility interferences,a split-flow injection valve,and an onboard He carrier–gas *** assembled unit measures 19×30×14 cm,weighs~3.5 kg,operates on AC power,and is laptop/LabVIEW ***-and system-level tests of performance demonstrated injection bandwidths o1 s,aμcolumn capacity of≥8μg injected mass,linear calibration curves,no humidity effects,excellent medium-term(that is,1 week)reproducibility,autonomous operation for 8 h,detection limits below Threshold Limit Values(TLV)for 10 mL air samples collected in 1 min,and response patterns that enhanced vapor *** determination of a 17-VOC mixture in the presence of seven interferences was performed in 4 *** augur well for adapting the microsystem to an all-MEMS wearableμGC currently under parallel development.

关键词： gas chromatography micro-GC microsystem mixtures sensor array VOCs

Additive nanomanufacturing of lab-on-a-chip fluorescent peptide nanoparticle arrays for Alzheimer＇s disease diagnosis

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Bio-Design and Manufacturing 2018年第3期1卷 182-194页

作者： Leming Sun Zhen Fan Tao Yues Jun Yin Jianzhong FU Mingjun Zhang Department of Biomedical Engineering College ofEngineering Ohio State University Columbus OH 43210USA School of Life Sciences Northwestern PolytechnicalUniversity Xi'an 710072 Shaanxi China Department of Polymeric Materials School of MaterialScience and Engineering Tongji UniversityShanghai 201804 China Institute for Advanced Study TongjiUniversity Shanghai 200092 China School of Mechatronic Engineering and Automation Shanghai University Shanghai 200444 China The State Key Laboratory of Fluid Power and Mechatronic Systems School of Mechanical Engineering ZhejiangUniversity Hangzhou 310028 China Key Laboratory of 3D Printing Process and Equipment of Zhejiang Province School of Mechanical EngineeringZhejiang University Hangzhou 310028 China Dorothy M. Davis Heart & Lung Research Institute The OhioState University Wexner Medical Center Columbus OH43210 USA Interdisciplinary Biophysics Graduate Program Ohio StateUniversity Columbus OH 43210 USA

This paper proposes an additive nanomanufacturing approach to fabricate a personalized lab-on-a-chip fluorescent peptide nanoparticles （f-PNPs） array for simultaneous multi-biomarker detection that can be used in Alzheimer＇s disease （AD） diagnosis. We will discuss optimization techniques for the additive nanomanufacturing process in terms of reliability, yield and manufacturing efficiency. One contribution of this paper lies in utilization of additive nanomanufacturing techniques to fabricate a patient-specific customize-designed lab-on-a-chip device for personalized AD diagnosis, which remains a major challenge for biomedical engineering. Through the integrated bio-design and bio-manufacturing process, doctor＇s check- up and computer-aided customized design are integrated into the lab-on-a-chip array for patient-specific AD diagnosis. In addition, f-PNPs with targeting moieties for personalized AD biomarkers will be self-assembled onto the customized lab-on-a- chip through the additive nanomanufacturing process, which has not been done before. Another contribution of this research is the personalized lab-on-a-chip f-PNPs array for AD diagnosis utilizing limited human blood. Blood-based AD assessment has been described as ＂the holy grail＂ of early AD detection. This research created the computer-aided design, fabrication through additive nanomanufacturing, and validation of the f-PNPs array for AD diagnosis. This is a highly interdisciplinary research contributing to nanotechnology, biomaterials, and biomedical engineering for neurodegenerative disease. The conceptual work is preliminary with intent to introduce novel techniques to the application. Large-scale manufacturing based on the proposed framework requires extensive validation and optimization.

关键词： Nanomanufacturing Lab-on-a-chip Fluorescent peptide nanoparticle Alzheimer＇s disease Diagnosis

Unifying femtosecond and picosecond single-pulse magnetic switching in GdFeCo

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arXiv 2020年

作者： Jakobs, F. Ostler, T.A. Lambert, C.-H. Yang, Y. Salahuddin, S. Wilson, R.B. Gorchon, J. Bokor, J. Atxitia, U. Dahlem Center for Complex Quantum Systems and Fachbereich Physik Freie Universität Berlin Berlin14195 Germany LiégeB-4000 Belgium College of Business Technology and Engineering Sheffield Hallam University Howard Street SheffieldS1 1WB United Kingdom Department of Electrical Engineering and Computer Sciences University of California BerkeleyCA94720 United States Department of Materials Science and Engineering University of California BerkeleyCA94720 United States Lawrence Berkeley National Laboratory 1 Cyclotron Road BerkeleyCA94720 United States Department of Mechanical Engineering and Materials Science and Engineering Program University of California RiversideCA92521 United States ETH Zurich Hönggerbergring 64 Zürich8093 Switzerland Portland Technology Development Department Intel Corp. HillsboroOR97006 United States Universite de Lorraine CNRS IJL NancyF-54000 France

Many questions are still open regarding the physical mechanisms behind the magnetic switching in GdFeCo alloys by single optical pulses. Phenomenological models suggest a femtosecond scale exchange relaxation between sublattice magnetization as the driving mechanism for switching. The recent observation of thermally induced switching in GdFeCo by using both several picosecond optical laser pulse as well as electric current pulses has questioned this previous understanding. This has raised the question of whether or not the same switching mechanics are acting at the femoand picosecond scales. In this work, we aim at filling this gap in the understanding of the switching mechanisms behind thermal single-pulse switching. To that end, we have studied experimentally thermal single-pulse switching in GdFeCo alloys, for a wide range of system parameters, such as composition, laser power and pulse duration. We provide a quantitative description of the switching dynamics using atomistic spin dynamics methods with excellent agreement between the model and our experiments across a wide range of parameters and timescales, ranging from femtoseconds to picoseconds. Furthermore, we find distinct element-specific damping parameters as a key ingredient for switching with long picosecond pulses and argue, that switching with pulse durations as long as 15 picoseconds is possible due to a low damping constant of Gd. Our findings can be easily extended to speed up dynamics in other contexts where ferrimagnetic GdFeCo alloys have been already demonstrated to show fast and energy-efficient processes, e.g. domain-wall motion in a track and spin-orbit torque switching in spintronics devices. Copyright © 2020, The Authors. All rights reserved.

关键词： Ternary alloys

Corrosion behaviour of PEEK or β-TCP-impregnated Ti6Al4V SLM structures targeting biomedical applications

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Transactions of Nonferrous Metals Society of China 2019年第12期29卷 2523-2533页

作者： M.M.COSTA T.A.DANTAS F.BARTOLOMEU N.ALVES F.S.SILVA G.MIRANDA F.TOPTAN Center for Micro Electro Mechanical Systems(CMEMS) University of Minho(UMinho)4800-058 GuimarãesPortugal MIT Portugal Program School of EngineeringUniversity of MinhoGuimarãesPortugal Centre for Rapid and Sustainable Product Development Polytechnic Institute of Leiria Rua General Norton de MatosApartado 4133LeiriaPortugal IBTN/Br–Brazilian Branch of the Institute of Biomaterials Tribocorrosion and NanomedicineUNESPCampus de BauruAv.Eng.Luiz Edmundo Carrijo Coube14-0117033-360BauruSPBrazil

Ti6Al4V cellular structures were produced by selective laser melting(SLM)and then filled either with beta-tricalcium phosphate(β-TCP)or PEEK(poly-ether-ether-ketone)through powder metallurgy techniques,to improve osteoconductivity and wear *** corrosion behavior of these structures was explored considering its importance for the long-term performance of *** revealed that the incorporation of open cellular pores induced higher electrochemical kinetics when being compared with dense *** impregnation ofβ-TCP and PEEK led to the creation of voids or gaps between the metallic matrix and the impregnated material which also influenced the corrosion behavior of the cellular structures.

关键词： Ti6Al4V cellular structures corrosion multimaterial design poly-ether-ether-ketone(PEEK) beta-tricalcium phosphate(β-TCP)

Using physical features of protein core packing to distinguish real proteins from decoys

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arXiv 2020年

作者： Grigas, Alex T. Mei, Zhe Treado, John D. Levine, Zachary A. Regan, Lynne O'Hern, Corey S. Graduate Program in Computational Biology and Bioinformatics Yale University New HavenCT06520 United States Integrated Graduate Program in Physical and Engineering Biology Yale University New HavenCT06520 United States Department of Chemistry Yale University New HavenCT06520 United States Department of Mechanical Engineering and Materials Science Yale University New HavenCT06520 United States Department of Pathology Yale University New HavenCT06520 United States Department of Molecular Biophysics and Biochemistry Yale University New HavenCT06520 United States Institute of Quantitative Biology Biochemistry and Biotechnology Centre for Synthetic and Systems Biology School of Biological Sciences University of Edinburgh Department of Physics Yale University New HavenCT06520 United States Department of Applied Physics Yale University New HavenCT06520 United States

The ability to consistently distinguish real protein structures from computationally generated model decoys is not yet a solved problem. One route to distinguish real protein structures from decoys is to delineate the important physical features that specify a real protein. For example, it has long been appreciated that the hydrophobic cores of proteins contribute signifficantly to their stability. As a dataset of decoys to compare with real protein structures, we studied submissions to the bi-annual CASP competition (speciffically CASP11, 12, and 13), in which researchers attempt to predict the structure of a protein only knowing its amino acid sequence. Our analysis reveals that many of the submissions possess cores that do not recapitulate the features that define real proteins. In particular, the model structures appear more densely packed (because of energetically unfavorable atomic overlaps), contain too few residues in the core, and have improper distributions of hydrophobic residues throughout the structure. Based on these observations, we developed a deep learning method, which incorporates key physical features of protein cores, to predict how well a computational model recapitulates the real protein structure without knowledge of the structure of the target sequence. By identifying the important features of protein structure, our method is able to rank decoys from the CASP competitions equally well, if not better than, state-of-the-art methods that incorporate many additional features. Copyright © 2020, The Authors. All rights reserved.

关键词： Proteins

Steady Rayleigh-BénardRayleigh-Bénard convection between stress-free boundaries

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arXiv 2020年

作者： Wen, Baole Goluskin, David LeDuc, Matthew Chini, Gregory P. Doering, Charles R. Department of Mathematics University of Michigan Ann ArborMI48109-1043 United States Department of Mathematics & Statistics University of Victoria VictoriaBCV8P 5C2 Canada Department of Physics University of Michigan Ann ArborMI48109-1040 United States Program in Integrated Applied Mathematics University of New Hampshire DurhamNH03824 United States Department of Mechanical Engineering University of New Hampshire DurhamNH03824 United States Center for the Study of Complex Systems University of Michigan Ann ArborMI48109-1042 United States

Steady two-dimensional Rayleigh-Bénard convection between stress-free isothermal boundaries is studied via numerical computations. We explore properties of steady convective rolls with aspect ratios π/5 ⩽ Γ ⩽ 4π, where Γ is the width-to-height ratio for a pair of counter-rotating rolls, over eight orders of magnitude in the Rayleigh number, 103 ⩽ Ra ⩽ 1011, and four orders of magnitude in the Prandtl number, 10−2 ⩽ Pr ⩽ 102. At large Ra where steady rolls are dynamically unstable, the computed rolls display Ra → ∞ asymptotic scaling. In this regime, the Nusselt number Nu that measures heat transport scales as Ra1/3 uniformly in Pr. The prefactor of this scaling depends on Γ and is largest at Γ ≈ 1.9. The Reynolds number Re for large-Ra rolls scales as Pr−1Ra2/3 with a prefactor that is largest at Γ ≈ 4.5. All of these large-Ra features agree quantitatively with the semi-analytical asymptotic solutions constructed by Chini & Cox (2009). Convergence of Nu and Re to their asymptotic scalings occurs more slowly when Pr is larger and when Γ is smaller. Copyright © 2020, The Authors. All rights reserved.

关键词： Prandtl number

A spectral method for solving heat and moisture transfer through consolidated porous media

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arXiv 2019年

作者： Gasparin, Suelen Dutykh, Denys Mendes, Nathan LAMA UMR 5127 CNRS Université Savoie Mont Blanc Campus Scientifique F-73376 Le Bourget-du-Lac Cedex France and Thermal Systems Laboratory Mechanical Engineering Graduate Program Pontifical Catholic University of Paraná Rua Imaculada Conceição 1155 Curitiba – ParanáCEP: 80215-901 Brazil Univ. Grenoble Alpes Univ. Savoie Mont Blanc CNRS LAMA Chambéry73000 France LAMA UMR 5127 CNRS Université Savoie Mont Blanc Campus Scientifique Le Bourget-du-Lac CedexF-73376 France Thermal Systems Laboratory Mechanical Engineering Graduate Program Pontifical Catholic University of Paraná Rua Imaculada Conceição 1155 Curitiba – ParanáCEP: 80215-901 Brazil

This work presents an efficient numerical method based on spectral expansions for simulation of heat and moisture diffusive transfers through multilayered porous materials. Traditionally, by using the finite-difference approach, the problem is discretized in time and space domains (Method of lines) to obtain a large system of coupled Ordinary Differential Equations (ODEs), which is computationally expensive. To avoid such a cost, this paper proposes a reduced-order method that is faster and accurate, using a much smaller system of ODEs. To demonstrate the benefits of this approach, tree case studies are presented. The first one considers nonlinear heat and moisture transfer through one material layer. The second case – highly nonlinear – imposes a high moisture content gradient – simulating a rain like condition – over a two-layered domain, while the last one compares the numerical prediction against experimental data for validation purposes. Results show how the nonlinearities and the interface between materials are easily and naturally treated with the spectral reduced-order method. Concerning the reliability part, predictions show a good agreement with experimental results, which confirm robustness, calculation efficiency and high accuracy of the proposed approach for predicting the coupled heat and moisture transfer through porous materials. Copyright © 2019, The Authors. All rights reserved.

关键词： Porous materials

Characterizing cellular mechanical phenotypes with mechanonode-pore sensing

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Microsystems & Nanoengineering 2018年第1期4卷 438-449页

作者： Junghyun Kim Sewoon Han Andy Lei Masaru Miyano Jessica Bloom Vasudha Srivastava Martha R.Stampfer Zev J.Gartner Mark A.LaBarge Lydia L.Sohn Department of Mechanical Engineering University of California at BerkeleyBerkeleyCA 94720-1740USA Department of Bioengineering University of California at BerkeleyBerkeleyCA 94720-1762USA Department of Population Sciences Beckman Research InstituteCity of HopeDuarteCA 91010USA Department of Pharmaceutical Chemistry University of CaliforniaSan FranciscoSan FranciscoCA 94143USA Biological Systems and Engineering Division Lawrence Berkeley National LaboratoryCA 94720USA Graduate Program in Bioengineering University of CaliforniaBerkeleyand University of CaliforniaSan FranciscoBerkeleyCA 94720USA

The mechanical properties of cells change with their differentiation,chronological age,and malignant ***,these properties may be useful label-free biomarkers of various functional or clinically relevant cell ***,we demonstrate mechano-node-pore sensing(mechano-NPS),a multi-parametric single-cell-analysis method that utilizes a four-terminal measurement of the current across a microfluidic channel to quantify simultaneously cell diameter,resistance to compressive deformation,transverse deformation under constant strain,and recovery time after *** define a new parameter,the whole-cell deformability index(wCDI),which provides a quantitative mechanical metric of the resistance to compressive deformation that can be used to discriminate among different cell *** wCDI and the transverse deformation under constant strain show malignant MCF-7 and A549 cell lines are mechanically distinct from non-malignant,MCF-10A and BEAS-2B cell lines,and distinguishes between cells treated or untreated with cytoskeleton-perturbing small *** categorize cell recovery time,ΔT_(r),as instantaneous(ΔTr~0 ms),transient(ΔT_(r)≤40 ms),or prolonged(ΔT_(r)>40 ms),and show that the composition of recovery types,which is a consequence of changes in cytoskeletal organization,correlates with cellular *** the wCDI and cell-recovery time,mechano-NPS discriminates between sub-lineages of normal primary human mammary epithelial cells with accuracy comparable to flow cytometry,but without antibody ***-NPS identifies mechanical phenotypes that distinguishes lineage,chronological age,and stage of malignant progression in human epithelial cells.

关键词： microfluidics mechanical phenotyping node-pore sensing biosensors label-free

Molding Compound Effects on Warpage of Fan-out Wafer Level Packaging

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Molding Compound Effects on Warpage of Fan-out Wafer Level P...

International Symposium on Electronic Materials and Packaging

作者： Yan-Cheng Liu Hsien-Chie Cheng Zong-Da Wu Ph.D. Program of Mechanical and Aeronautical Engineering Feng Chia University Taichung Taiwan ROC Department of Aerospace and Systems Engineering Feng Chia University Taichung Taiwan ROC

ISBN: (纸本)9781538656433;9781538656426

Fan-out Wafer-level Packaging (FOWLP) technology has become one of the most rapid packaging technologies which can meet consumer demand for electronic devices. Since there are many advantages to FOWLP, several important issues remain to be addressed, including yield, reliability, thermal performance, die shift, and warpage. Therefore, the main reasons that cause the yield problem of the FOWLP are the mismatch of temperature loading and coefficient of thermal expansion(CTE) among the components of the package, and the other reason is the chemical shrinkage of liquid type epoxy molding compound during the cure process. In this study, the main goal is to assess the process-induced warpage of FOWLP during the fabrication process. To predict the amount of warpage precisely, a process-dependent simulation model which includes the cure-induced shrinkage of the liquid type of molding compound obtained by measurement is proposed. To confirm the validity of the simulation model, the simulation results are compared to the online warpage measurement data. Finally, the influence of the material properties of molding compound parameters on the process-induced warpage is discussed.

关键词： Compounds Semiconductor device modeling Fabrication Packaging Solid modeling Wafer scale integration