Recent progress on non-thermal plasma technology for high barrier layer fabrication

This review describes the application of non-thermal plasma（NTP） technology for high barrier layer fabrication in packaging area.NTP technology is considered to be the most prospective approaches for the barrier layer fabrication over the past decades due to unpollution,high speed,low-costing.The applications of NTP technology have achieved numerous exciting results in high barrier packaging area.Now it seemly demands a detailed review to summarize the past works and direct the future developments.This review focuses on the different NTP resources applied in the high barrier area,the role of plasma surface modification on packaging film surface properties,and the deposition of different barrier coatings based on NTP technology.In particular,this review emphasizes the cutting-edge technologies of NTP on interlayer deposition with organic,inorganic for multilayer barriers fabrication.The future prospects of NTP technology in high barrier film areas are also described.

Fabrication and characterization of iron and iron carbide thin films by plasma enhanced pulsed chemical vapor deposition

A new pulsed chemical vapor deposition (PCVD) process has been developed to fabricate iron (Fe) and iron carbide (Fe1-xCx) thin films at low temperature range from 150℃ to 230℃. The process employs bis(1,4-di-tert-butyl-1,3-diazabutadienyl)iron(II) as iron source and hydrogen gas or hydrogen plasma as the coreactant. The films deposited with hydrogen gas are demonstrated polycrystalline with body-centered cubic Fe. However, for the films deposited with hydrogen plasma, the amorphous phase of iron carbide is obtained. The influence of the deposition temperature on iron and iron carbide characteristics have been investigated.

Insight into the remaining high surface energy of atmospheric DBD plasma-treated polyethylene web after three months' aging

In this paper, we report the modification of polyethylene(45 μm in thickness) webs through a roll-to-roll dielectric barrier discharge plasma treatment in an open atmospheric environment.Our work differs from the normal adopted corona discharge treatment at an atmospheric pressure, in that three monomers: allylamine, acrylic acid, and ethanol, are inlet into the discharge zone by argon(Ar) carrier gas. As a comparison, Ar plasma treatment is also carried out. We focus on the aging properties of treated plastics in the open air. It is found that the modified webs can retain the surface energy as high as 50.0?±?1 mN m^(-1) for more than three months. After characterization of the as-prepared and aged samples by the surface roughness, the wettability, and the chemical structure, the mechanism of retaining high surface energy is then presumed. We think that the initial high surface energy just after plasma treatment is correlated to the grafted functional groups, while the over 50.0 mN m^(-1) remaining surface energy after three month aging is due to the stable concentrations of oxygen-contained and nitrogencontained groups by post-reaction on the surfaces.

Preparation of palladium-based catalyst by plasma-assisted atomic layer deposition and its applications in CO_(2) hydrogenation reduction

Supported Pd catalyst is an important noble metal material in recent years due to its high catalytic performance in CO_(2)hydrogenation.A fluidized-bed plasma assisted atomic layer deposition(FP-ALD) process is reported to fabricate Pd nanoparticle catalyst over γ-Al_(2)O_(3)or Fe_(2)O_(3)/γ-Al_(2)O_(3)support,using palladium hexafluoroacetylacetonate as the Pd precursor and H_(2)plasma as counter-reactant.Scanning transmission electron microscopy exhibits that highdensity Pd nanoparticles are uniformly dispersed over Fe_(2)O_(3)/γ-Al_(2)O_(3)support with an average diameter of 4.4 nm.The deposited Pd-Fe_(2)O_(3)/γ-Al_(2)O_(3)shows excellent catalytic performance for CO_(2)hydrogenation in a dielectric barrier discharge reactor.Under a typical condition of H_(2)to CO_(2)ratio of 4 in the feed gas,the discharge power of 19.6 W,and gas hourly space velocity of10000 h^(-1),the conversion of CO_(2)is as high as 16.3% with CH_(3)OH and CH4selectivities of 26.5%and 3.9%,respectively.

Integrating PCR-free amplification and synergistic sensing for ultrasensitive and rapid CRISPR/Cas12a-based SARS-CoV-2 antigen detection

Antigen detection provides particularly valuable information for medical diagnoses;however,the current detection methods are less sensitive and accurate than nucleic acid analysis.The combination of CRISPR/Cas12a and aptamers provides a new detection paradigm,but sensitive sensing and stable amplification in antigen detection remain challenging.Here,we present a PCR-free multiple trigger dsDNA tandem-based signal amplification strategy and a de novo designed dual aptamer synergistic sensing strategy.Integration of these two strategies endowed the CRISPR/Cas12a and aptamer-based method with ultra-sensitive,fast,and stable antigen detection.In a demonstration of this method,the limit of detection was at the single virus level(0.17 fM,approximately two copies/μL)in SARS-CoV-2 antigen nucleocapsid protein analysis of saliva or serum samples.The entire procedure required only 20 min.Given our system’s simplicity and modular setup,we believe that it could be adapted reasonably easily for general applications in CRISPR/Cas12a-aptamer-based detection.

High-throughput and reliable acquisition of in vivo turnover number fuels precise metabolic engineering

As synthetic biology enters the era of quantitative biology,mathematical information such as kinetic parameters of enzymes can offer us an accurate knowledge of metabolism and growth of cells,and further guidance on precision metabolic engineering.k_(cat),termed the turnover number,is a basic parameter of enzymes that describes the maximum number of substrates converted to products each active site per unit time.It reflects enzyme activity and is essential for quantitative understanding of biosystems.Usually,the k_(cat) values are measured in vitro,thus may not be able to reflect the enzyme activity in vivo.In this case,Davidi et al.defined a surrogate K^(vivo)_(max)(k_(app))for kcat and developed a high throughput method to acquire K^(vivo)_(max)from omics data.Heckmann et al.and Chen et al.proved that the surrogate parameter can be a good embodiment of the physiological state of enzymes and exhibit superior performance for enzyme-constrained metabolic model to the default one.These breakthroughs will fuel the development of system and synthetic biology.