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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

Meso-Scale VOC-Mixture Analyzer with tunable Separation and Microsensor Array Detection

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稀有金属材料与工程 2006年第A3期35卷 61-64页

作者： Qiongyan Zhong William H. Steinecker edward t. zellers Department of Environmental Health Sciences University of Michigan 109 S. Observatory St. Ann Arbor MI 48109-2029 USA Department of Chemistry University of Michigan 109 S. Observatory St. Ann Arbor MI 48109-2029 USA

关键词： microsensor gas chromatography nanoparticle sensor array portable EtS

“Plasmonics”in free space:observation of giant wavevectors,vortices,and energy backflow in superoscillatory optical fields

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Light(Science & Applications) 2019年第1期8卷 1161-1169页

作者： Guanghui Yuan edward t.F.Rogers Nikolay I.Zheludev Centre for Disruptive Photonic technologies The Photonic InstituteSchool of Physical and Mathematical SciencesNanyang Technological UniversitySingapore 637371Singapore Optoelectronics Research Centre and Centre for Photonic Metamaterials University of SouthamptonHighfieldSouthampton SO171BJUK Institute for Life Sciences University of SouthamptonHighfieldSouthampton SO171BJUK

Evanescent light can be localized at the nanoscale by resonant absorption in a plasmonic nanoparticle or taper or by transmission through a ***,a conventional lens cannot focus free-space light beyond half of the wavelength λ.Nevertheless,precisely tailored interference of multiple waves can form a hotspot in free space of an arbitrarily small size,which is known as ***,we report a new type of integrated metasurface interferometry that allows for the first time mapping of fields with a deep subwavelength resolution ~λ/*** findings reveal that an electromagnetic field near the superoscillatory hotspot has many features similar to those found near resonant plasmonic nanoparticles or nanoholes:the hotspots are surrounded by nanoscale phase singularities and zones where the phase of the superoscillatory field changes more than tenfold faster than a freepropagating plane *** with high local wavevectors are pinned to phase vortices and zones of energy backflow(~λ/20 in size)that contribute to tightening of the main focal spot size beyond the Abbe-Rayleigh *** observations reveal some analogy between plasmonic nanofocusing of evanescent waves and superoscillatory nanofocusing of free-space waves and prove the fundamental link between superoscillations and superfocusing,offering new opportunities for nanoscale metrology and imaging.

关键词： metrology free wave

Mini-Review:Green sustainable processes using supercritical fluid carbon dioxide

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Journal of Environmental Sciences 2009年第6期21卷 720-726页

作者： RAMSEY edward University of Science and technology Liaoning

Environmentally benign carbon dioxide offers significant potential in its supercritical fluid phase to replace current reliance on a range of hazardous, relatively expensive and environmentally damaging organic solvents that are used on an extensive global basis. the unique combination of the physical properties of supercritical fluids are being exploited and further researched to continue the development and establishment of high efficiency, compact plant to provide energy and water efficient manufacturing processes. this mini-review is focused on the use and potential applications of supercritical fluid carbon dioxide for a selected range of key and emerging industrial processes as a sustainable alternative to totally eliminate or greatly reduce the requirement of numerous conventional organic solvents. Examples of the industries include： chemical extraction and purification, synthetic chemical reactions including polymerization and inorganic catalytic processes. Biochemical reactions involving enzymes, particle size engineering, textile dyeing and advanced material manufacture provide further illustrations of vital industrial activities where supercritical fluid technology processes are being implemented or developed. Some aspects relating to the economics of sustainable supercritical fluid carbon dioxide processes are also considered.

关键词： supercritical extraction synthesis catalysis enzymes polymerization particles dyeing

Studies on the Lattice Distortion and Substructures of Shocked Lamellae in Naturally Shocked Quartz

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Acta Geochimica 1987年第1期6卷 19-32页

作者：谢先德 edward C. t. CHAO Institute of Geochemistry Academia Sinica United States Geological Survey Mailstop 929 Reston Va 22092 United States of America

One unshocked and 9 naturally shocked single quartz crystal grains with 1-6 sets of shock lamellaefrom the Ries, West Germany, and the Lake Lappajarvi, Finland, covering a range from unshocked quartzwith _disibledevent=1.544 to nearly completely glassy quartz with _disibledevent=1.461 have been used for X-ray precessionand Laue investigations. Four of the shocked grains have preliminarily been studied under a transmissionelectron microscope. It is found that quartz having No less than 1.539 shows intensive anisotropic cellexpansion and lattice disordering which gradually increase as No decreases. Shock-induced lattice distortionof quartz is clearly shown on both precession and Laue photographs. For the weakly shocked quartz (pt to pronounced spreading of spots is observed. When the pressure reaches 200 kb, both concentricspreading of spots having long ‘tails' and concentric rings (powder pattern) are revealed on the samephotograph, which means that besides a part of single crystal there also exist randomly oriented tiny‘fragments' of quartz in this shocked quartz grain. As pressure increases from 230 to 315 kb, more and morecrystalline puases in the quartz grains have transformed from solid state into silica glass, and the concentricrings and the long ‘tails' disappear and the spot spreading becomes slight again, but reflection intensitiesbecome much lower in comparison with those of weakly shocked quartz. tEM investigations show three kinds of substructures of shock lamellae. the glass contents of two ofthe four grains (73% and 84% respectively) were measured on tEM photographs with the help of an imageanalysis system. On the basis of above investigations a six-terminal-state model for the mechanism of deformation inshock metamorphosed quartz is presented.

关键词： Studies on the Lattice Distortion and Substructures of Shocked Lamellae in Naturally Shocked Quartz

Lactate: an intracellular metabolite regulates cell cycle progression

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Life Metabolism 2023年第4期2卷 1-2页

作者： Jinke Cheng edward t.H.Yeh Department of Biochemistry and Molecular Cell Biology Shanghai Key Laboratory for Tumor Microenvironment and InflammationShanghai Jiao Tong University School of MedicineShanghai 200025China Department of Internal Medicine University of Arkansas for Medical SciencesLittle RockAR 72205United States

the Chouchani lab recently reported in Nature that a dynamic intracellular lactate is a physiological regulator for cell cycle *** also showed that accumulated lactate in cell mitosis directly binds and inhibits Sentrin/SUMO-specific pro-tease 1 to enrich SUMO2/3-modification of anaphase-promot-ing complex 4(APC4),which promotes the degradation of APC/C complexes,leading to mitosis exit.

关键词： cycle complexes accumulated

High-order schemes for predicting computational aeroacoustic propagation with adaptive mesh refinement

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Acta Mechanica Sinica 2013年第1期29卷 1-11页

作者： edward Peers Xun Huang State Key Laboratory for turbulence and Complex Systems Department of Aeronautics and Astronautics College of Engineering Peking University

High-order schemes based on block-structured adaptive mesh refinement method are prepared to solve computational aeroacoustic （CAA） problems with an aim at improving computational efficiency. A number of numerical issues associated with high-order schemes on an adaptively refined mesh, such as stability and accuracy are addressed. Several CAA benchmark problems are used to demonstrate the feasibility and efficiency of the approach.

关键词： Adaptive mesh Aeroacoustics High-order schemes

Sustainable oil-in-water analysis using a supercritical fluid carbon dioxide extraction system directly interfaced with infrared spectroscopy

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Journal of Environmental Sciences 2010年第9期22卷 1462-1468页

作者： edward D.Ramsey School of Chemical Engineering University of Science and Technology Liaoning

A direct aqueous supercritical fluid extraction （SFE） system using carbon dioxide provides a sustainable means by which a vast range of industries may continue to depend on well established infrared （IR） techniques to determine oil-in-water. the SFE-IR method provides an environmentally friendly substitute for current national standard IR reference methods for measuring oil-in-water that rely on using increasingly restricted ozone depleting solvents whose manufacture is being phased out in accordance with international law. the SFE-IR analysis of a 500 mL water sample can be accomplished in 15 min. A rapid on-line SFE-IR calibration method has been implemented. With this calibration method, SFE-IR accuracy for determining diesel oil in 500 mL spiked water samples using single wave number measurement was 86.0%-98.8% with precision （RSD） ranging from 2.5%-7.0%. Using a general purpose calculation which involves measuring infrared absorbance values at three different wave numbers, SFE-IR method accuracy for determining diesel oil in 500 mL spiked water samples was 83.7%-92.2% with RSD 1.0%-9.3%. Data is presented that indicates current long established national standard IR reference methods involving three wave number calculations should be reviewed since, without careful consideration, the inclusion of calculated aromatic hydrocarbon species contributions to final oil-in-water concentration values may provide less accurate results.

关键词： oil-in-water supercritical fluid extraction infrared spectroscopy sustainable green technology

two Potent α3/5 Conotoxins from Piscivorous Conus achatinus

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Acta Biochimica et Biophysica Sinica 2007年第6期39卷 438-444页

作者： Geoffrey CHEW edward HAWROt Department of Molecular Pharmacology Physiology and Biotechnology Brown University Providence Rhode Island 02903 USA

Every cone snail produces a mixture of different conotoxins and secretes them to immobilize their prey and predators. α3/5 Conotoxins, isolated from fish-hunting cone snails, target muscle nicotinic acetylcholine receptors. the structure and function of α3/5 conotoxin from the piscivorous Conus achatinus have not been studied. We synthesized two pentadecamer peptides, Ac 1.1 a and Ac 1.1 b, with appropriate disulfide bonding, based on cDNA sequences of α3/5 conotoxins from C. achatinus. Ac 1.1 a and Ac 1.1 b differ by only one amino acid residue. they have similar potency on blocking recombinant mouse muscle acetylcholine receptor expressed in Xenopus laevis oocytes, with IC50values of 36 nM and 26 nM, respectively. For Ac 1.1b, deletion of the first three N-terminal amino acids did not change its activity, indicating that the Nterminus is not involved in the interaction with its receptor. Furthermore, our experiments indicate that both toxins strongly prefer the α1-δ subunit interface instead of the α1-γ binding site on the mouse muscle nicotinic acetylcholine receptor. these peptides provide additional tools for the study of the structure and function of nicotinic receptor.

关键词： cone snail α3/5 conotoxin disulfide bond nicotinic acetylcholine receptor