Background: The quest toward an artificial β-cell has been accelerating, propelled by recent technological advances in subcutaneous glucose sensors and insulin pumps. The development and clinical testing of algorithm...
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In an offset printing process, the ink film splitting event has some relationship to the tack forces experienced by the paper and has an important impact on formation of ink filaments. The filament size and its distri...
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ISBN:
(纸本)9781605605104
In an offset printing process, the ink film splitting event has some relationship to the tack forces experienced by the paper and has an important impact on formation of ink filaments. The filament size and its distribution are expected to influence the leveling of ink and hence impact ink setting, the print gloss dynamics and the print quality. However, ink filaments are difficult to image due to their short life time and fine length scale. Limited work has been reported on the parameters that influence filament size and methods to characterize this size. This work attempts to image ink filament remains and to quantify some of their characteristics such as height and diameter as other parameters, such as printing speed, ink amount and fountain solution type are changed. Printed samples were prepared using a laboratory printability tester at varying ink level and operating settings. Influence of printing speed, ink grammage and fountain solution were probed. Rhodamine B dye was incorporated into fountain solutions to aid the detection of them. The prints were then imaged with a Confocal Laser Scanning Microscope (CLSM) and images were further analyzed for their surface topography. Modeling of the pressure pulses in the printing nip is included in order to better understand the mechanism of filament formation and the origin of filament length scale. Printing speed and ink amount changed the size distribution of the observed filament remains. Addition of different fountain solutions, with or without isopropyl alcohol, did not have a significant influence on observed filament remain patterns.
The polymerizations of n-butyl methylacrylate (nBMA) were carried out using bis(/3-ketoamino)nickel(II) complexes (Ni[CH3C(O)CHC(NR)CH 3]2: R = phenyl, 1;R = naphthyl, 2) in combination with methylaluminoxane (MAO) in...
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The polymerizations of n-butyl methylacrylate (nBMA) were carried out using bis(/3-ketoamino)nickel(II) complexes (Ni[CH3C(O)CHC(NR)CH 3]2: R = phenyl, 1;R = naphthyl, 2) in combination with methylaluminoxane (MAO) in toluene. The effect of parameters such as polymerization temperature, Al/Ni molar ratios, polymerization time, and monomer concentration, on catalytic polymerization activity and polymer molecular weights, were examined in detail. Both of the nickel(II) catalytic systems exhibited moderate activity, and produced P(nBMA) with high molecular weight and relatively broad molecular weight distribution (Mw/Mn = 2.0∼3.0. The obtained polymer has been characterized by means of FTIR, 1H NMR, 13C NMR, DSC, and WAXD technique and was confirmed to be syndio-rich stereospecific P(nBMA).
In this work, poly(3-ethylenedioxythiophene) (PEDOT) was synthesized on glass by spin coating for 10 seconds at 500 rpm and polymerization was carried out in an oven at 110°C for 10 min. Methanol and water mixtur...
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In this work, poly(3-ethylenedioxythiophene) (PEDOT) was synthesized on glass by spin coating for 10 seconds at 500 rpm and polymerization was carried out in an oven at 110°C for 10 min. Methanol and water mixture were used as the solvent and dodecylbenzene sulfonic acid (DBSA) as the surfactant. The conductivities of films were measured and their relationship with different solvent or various surfactant contents were discussed. The morphology of films was observed by SEM, and PEDOT synthesized in methanol-rich solvents or with less DBSA content had more smooth surfaces, showed lower degradation temperature (by TGA). Also, PEDOT synthesized in methanol-rich solvents or with less DBSA were doped better, as observed by UV-Vis spectra.
作者：
Liping HengYongqiang DongJin ZhaiBen Zhong TangTianxin WeiLei JiangDepartment of Chemistry
the Hong Kong University of Science & Technology Clear Water BayKowloonHong Kong China Institute for Chemical PhysicsBeijing Institute of TechnologyBeijing 100081China Center for Molecular Science
Institute of ChemistryChinese Academy of SciencesBeijing 100080 China Department of Polymer Science and Engineering Zhejiang UniversityHangzhou 310027 China Department of Polymer Science and Engineering Zhejiang UniversityHangzhou 310027 China
This research developed the moisture-resistance of printed circuit board (PCB) laminate prototypes based on the non-toxic composite materials made from epoxidized linseed oil, melamine polyphosphate, and flax fibers. ...
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ISBN:
(纸本)9781424422722
This research developed the moisture-resistance of printed circuit board (PCB) laminate prototypes based on the non-toxic composite materials made from epoxidized linseed oil, melamine polyphosphate, and flax fibers. One of the key issues associated with using renewable base materials in composites is their sensitivity to moisture. A characterization of the properties of the 'green' printed circuit boards developed in the present study showed that moisture absorption for untreated fiber laminates (4.87% vs. established limit <0.8% for FR4 boards over a 24 hour submersion period) compromised electrical resistance and decreased dielectric breakdown to an unacceptable level. A theoretical model was used to target methods for reducing moisture absorption. Based on this model, we found that reductions in fiber diffusivity and fiber volume fraction substantially reduce composite diffusivity. Through the use of chemical treatment, moisture absorption over a 24 hour time period was reduced from 4.87% to 1.15%, which improved electrical properties. At the end of this study, 15 of 18 PCB property requirements were met, while 3 moisture-critical property targets were narrowly missed.
We report dynamic Monte Carlo simulations of immiscible binary polymer blends, which exhibit weakly enhanced crystal nucleation near interfaces between two phase-separated polymers. We found that this enhancement is n...
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We report dynamic Monte Carlo simulations of immiscible binary polymer blends, which exhibit weakly enhanced crystal nucleation near interfaces between two phase-separated polymers. We found that this enhancement is not accompanied by any preferred crystal orientation, implying its origin is mainly of enthalpic rather than entropic nature. Mean-field theory of polymer blends predicts that for immiscible polymers the melting point of the crystallizable component increases upon dilution in the other component, while it normally decreases for miscible blends. A local dilution is forced to occur at the diffuse interface of immiscible polymers; therefore the melting point of crystallizable polymers rises, which, in turn, enhances the thermodynamic driving force for crystal nucleation near the interface.
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