This article presents the 2-D numerical simulation results of the heavy-ion-induced leakage current degradation and single-event burnout (SEB) in the rated 1.2-kV silicon-carbide (SiC) super-junction ...(SJ) vertical diffusion metal-oxide-semiconductor (VDMOS). The employed simulation physics models were validated by the heavy-ion irradiation experiments of the commercially rated 1.2-kV SiC common VDMOS (C-VDMOS), which indicated a severe degeneration threshold of 500 V. The SiC common SJ VDMOS (C-SJ VDMOS) was proven to be sensitive to high-energy heavy-ion and represents comparative SEB performance compared with the SiC C-VDMOS. The robustness of the SiC SJ VDMOS with different single buffer layer (SBL) designs against a heavy-ion was simulated. It is found that the maximum temperature in the source metal/SiC interface and bottom of the structure could be compromised by the thickness of the buffer layer. As a result, the SiC SJ VDMOS with an optimal SBL exhibited a severe degeneration threshold of 800 V, which was a 60% increase compared to the SiC C-SJ VDMOS.
In this study, a series of cholesteric liquid crystal elastomers (ZSD series) was synthesised by hydrosilylation reaction among monomer ML
1
containing cholesteryl group, monomer ML
2
as the ...crosslinking agent, monomer ML
3
containing D(+)-camphoric acid group. The chemical structures and mesogenic properties of monomers and elastomers were studied by conventional testing methods. By characterising the liquid crystal elastomers, it was found that they all showed colourful Grandjean texture, good elasticity and high thermal stability. For the ZSD series, the values of T
g
first decreased and then increased and the values of T
i
always decreased with the change of the content of chiral liquid crystal monomers, and all elastomers had the wide mesophase temperature ranges (ΔT). ZSD
1
-ZSD
3
had selective reflection in the visible light region, while the observation for ZSD
4
-ZSD
7
could only be observed under the appropriate external pressure. The effect of the novel chiral monomer (ML
3
) on the properties of elastomers had been investigated.
Intrauterine adhesion (IUA) is one of the leading causes of infertility and the main clinical challenge is the high recurrence rate. The key to solving this dilemma lies in elucidating the mechanisms ...of endometrial fibrosis. The aim of our team is to study the mechanism underlying intrauterine adhesion fibrosis and the origin of fibroblasts in the repair of endometrial fibrosis.
Our experimental study involving an animal model of intrauterine adhesion and detection of fibrosis-related molecules. The levels of molecular factors related to the endothelial-to-mesenchymal transition (EndMT) were examined in a rat model of intrauterine adhesion using immunofluorescence, immunohistochemistry, qPCR and Western blot analyses. Main outcome measures are levels of the endothelial marker CD31 and the mesenchymal markers alpha-smooth muscle actin (α-SMA) and vimentin.
Immunofluorescence co-localization of CD31 and a-SMA showed that 14 days after moulding, double positive cells for CD31 and a-SMA could be clearly observed in the endometrium. Decreased CD31 levels and increased α-SMA and vimentin levels indicate that EndMT is involved in intrauterine adhesion fibrosis.
Endothelial cells promote the emergence of fibroblasts via the EndMT during the endometrial fibrosis of intrauterine adhesions.
Three zinc(II) metal-organic frameworks have been solvothermally synthesized with V-shaped 1,3-bis(1-imidazolyl)benzene (bib) and 4,4'-oxydibenzoic acid (4,4'-H2oba), namely {Zn(bib)(oba)⋅solvents}n ...(1), {Zn(bib)(oba)·2H2O}n (2) and {Zn2(bib)2(oba)2⋅2EtOH⋅H2O}n (3). All of them are characterized by single-crystal X-ray diffraction, infrared spectra and powder X-ray diffraction. Complex 1 presents a two-fold interpenetrating three-dimensional structure with 4-connected (65.8) topology. While, complexes 2 and 3 exhibit double layer cavity and double chains based two-dimensional structure, respectively. Luminescent studies indicate that 2 and 3 display selectively sensitive to electron-deficient nitroaromatic explosives with excellent anti-interference abilities.
Three zinc(II) metal-organic frameworks have been synthesized by the regulation of temperature- and solvent. Complexes 2 and 3 show selectively sensitive to electron-deficient nitroaromatic explosives with excellent anti-interference abilities. Display omitted
•Complexes 1–3 exhibit 2D/3D structures derived from V-shaped bib and H2oba with different conformations.•Through the change of reaction conditions, the assembly of MOFs with novel structures and interesting properties has been successfully realized.•Complexes 2 and 3 exhibit selectively sensitive to electron-deficient nitroaromatic explosives with high anti-interference abilities.
Electric field-assisted sintering has ubiquitous merits over conventional sintering technology for the fabrication of difficult-to-deform materials. To investigate the effect of sintering pressure ...and temperature on the densification of Inconel 718 superalloy, a numerical simulation model was established based on the Fleck-Kuhn-McMeeking (FKM) and Gurson-Tvergaard-Needleman (GTN) models, which covers a wide range of porosity. At a sintering pressure below 50 MPa or a sintering temperature below 950 °C, the average porosity of the sintered superalloy is over 0.17 with low densification. Under a pressure above 110 MPa and a temperature above 1250 °C, the sintered superalloy quickly completes densification and enters the plastic yield stage, making it difficult to control the sintering process. When the pressure is above 70 MPa while the temperature exceeds 1150 °C, the average porosity is 0.11, with little fall when the pressure or temperature rises. The experimental results indicated that the relative density of the sintered superalloy under 70 MPa and 1150 °C is 94.46%, and the proportion of the grain size below 10 μm is 73%. In addition, the yield strength of the sintered sample is 512 MPa, the compressive strength comes to 1260 MPa when the strain is over 0.8, and the microhardness is 395 Hv, demonstrating a better mechanical property than the conventional superalloy.
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•An efficient platform for 3D IgG immobilization is proposed.•The platform is based on the site-specific covalent attachment of Z-Cys onto solid.•The Z-Cys is immobilized in a ...site-specific, oriented, and irreversible attachment manner.•The IgG-binding characteristic of the immobilized Z-Cys was investigated using HPLC.•The proposed approach may be extended to other biochip or biosensor applications.
Immobilized antibodies with oriented and homogeneous patterns are crucial to solid-phase molecular recognition assay. Antibody binding protein-based immobilization can effectively present the desired antibodies. However, steadily installing the stromatoid protein with site-specific attachment manner onto a matrix surface remains to be elucidated. In this study, we present an optimal protocol to tightly attach an immunoglobulin G (IgG)-binding protein (Z-domain) through covalent incorporation of Cys-tag and maleimide group onto polystyrene surface to guarantee site-specific, oriented, and irreversible attachment, resulting in a highly efficient platform for three-dimensional IgG immobilization. The actual IgG-binding characteristic of immobilized Z-Cys was investigated by employing affinity chromatography and size exclusion chromatography. And the efficacy and potential of this platform was demonstrated by applying it to the analysis of interaction between rabbit anti-HRP IgG and its binding partner HRP. The proposed approach may be an attractive strategy to construct high performance antibody arrays and biosensors given that the antibody is compatible with the Z-domain.
Geophysical well-log evaluation in the era of unconventional hydrocarbon resources (mainly tight oil and gas, shale oil and gas) is complicated and challenging. This review aims to fill this gap ...between well-log evaluation and unconventional hydrocarbon resources by characterizing the source rock property, reservoir property and engineering property using petrophysical well logs. The advanced well-log series used for unconventional oil and gas evaluation include nuclear magnetic resonance (NMR) log, image logs, array acoustic logs, elemental capture spectroscopy (ECS) and LithoScanner logs. The source rock property in terms of total organic carbon content is predicted using conventional logs and LithoScanner log. Then petrophysical parameters including porosity, permeability and oil saturation are calculated, and the appearance of natural fracture is predicted from conventional, sonic logs, image logs and NMR logs. Additionally, the reservoir property is evaluated to optimize the favorable layers with high hydrocarbon bearing property and productivity. Brittleness index as well as in situ stress direction and magnitudes are characterized by the comprehensive use of density, sonic log, ECS log and image logs. Then, the engineering property (high brittleness index but low horizontal stress difference) is evaluated to screen out the prospected layers for hydraulic fracturing. The internal relationships between the three types of properties are unraveled, and the geological and engineering sweet spots are optimized by integrating lithology, reservoir quality, hydrocarbon bearing property, source rock property, brittleness and in situ stress magnitude and direction. This multidisciplinary approach provides a comprehensive method for optimizing sweet spots in unconventional play, and will support petroleum geoscientists’ and engineers’ decisions in exploration and exploitation of unconventional hydrocarbon resources.
Due to the local emissions and transportations of air pollution from the most polluted regions such as the North China Plain and Yangtze Delta metropolitan, Xuzhou is becoming one of the most ...polluted cities in East China. The sources and formation processes of nitrogen-containing aerosols are therefore very complex. Two continuous aerosol measurement campaigns were conducted in this industrial city during the wintertime and summertime of 2016, to investigate the chemical compositions and potential sources of total nitrogen (TN, including 89% inorganic nitrogen and 11% organic nitrogen) in PM2.5. Abrupt enhancements of nitrogen-containing aerosols (e.g., NO3− and NH4+) were found in the winter, and nitrate became as a dominant contributor in high pollution days (e.g., PM2.5 > 150 μg m−3). Nitrogen oxidation ratios (NOR) correlated significantly with aerosol liquid water content (ALWC), which was estimated by ISORPROPIA-II model. This suggested heterogeneous process might be an important pathway in nitrate formation during the high PM2.5 days. The nitrogen isotope composition (δ15N) in TN varied from −1.3 to +13.2‰ with a mean value of 6.9 ± 3.6‰ during the wintertime. An isotope-based source apportionment approach was then developed using a Bayesian isotope mixing model (SIAR) with chemical compositions as an important constrain, which improved accuracy and reduced the overall uncertainties in estimations of TN sources. From this optimized model, we identified six major sources including NH3 from combustion-related emissions (49%), NH3 derived from animal wastes (6%), NH3 from urban volatilization (3%), NOx derived from coal combustion (33%), NOx from biomass burning (5%) and NOx from vehicles (3%). Our results demonstrated that ambient NOx was dominated by coal combustion. Since NOx and NH3 are important precursors for ammonium nitrate aerosols, controlling of combustion related NOx and NH3 emissions might be an important way to reduce PM2.5 levels in this region.
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•Nitrate was the dominant contributor of water soluble inorganic ions in high PM2.5 pollution days.•The optimized Bayesian isotope mixing model (SIAR) improved accuracy and reduced the overall uncertainties, indicating modified SIAR improve accuracy in estimations of TN sources.•Combustion related NOx and NH3 emissions were the most predominant sources to nitrogen-containing aerosols (TN).
Atherosclerosis (AS) is a state of heightened oxidative stress characterized by lipid and protein oxidation in vascular walls. Oxidative stress-induced vascular endothelial cell (VEC) injury is a ...major factor in the pathogenesis of AS. Myricitrin, a natural flavonoid isolated from the root bark of Myrica cerifera, was recently found to have a strong antioxidative effect. However, its use for treating cardiovascular diseases, especially AS is still unreported. Consequently, we evaluated the cytoprotective effect of myricitrin on AS by assessing oxidative stress-induced VEC damage. The in vivo study using an ApoE−/−mouse model of AS demonstrated that myricitrin treatment protects against VEC damage and inhibits early AS plaque formation. This effect is associated with the antioxidative effect of myricitrin, as observed in a hydrogen peroxide (H2O2)-induced rat model of artery endothelial injury and primary cultured human VECs. Myricitrin treatment also prevents and attenuates H2O2-induced endothelial injury. Further investigation of the cytoprotective effects of myricitrin demonstrated that myricitrin exerts its function by scavenging for reactive oxygen species, as well as reducing lipid peroxidation, blocking NO release, and maintaining mitochondrial transmembrane potential. Myricitrin treatment also significantly decreased H2O2-induced apoptosis in VECs, which was associated with significant inhibition of p53 gene expression, activation of caspase-3 and the MAPK signaling pathway, and alteration of the patterns of pro-apoptotic and anti-apoptotic gene expression. The resulting significantly increased bcl-2/bax ratio indicates that myricitrin may prevent the apoptosis induced by oxidative stress injury.
•Myricitrin prevents early atherosclerosis in ApoE−/− mice.•Myricitrin protects endothelial cell from H2O2 induced injury in rat and HUVECs.•Myricitrin enhanced NO release and up regulates eNOS activity in HUVECs.•Myricitrin down regulates P53 expression and MAPKs phosphorylation in HUVECs.
This paper proposes a reverse conducting insulated gate bipolar transistors (RC-IGBT) structure with a raised N-buffer layer (RNB-IGBT) to improve the single-event burnout (SEB) robustness. The ...electrical and radiation properties of the structure were verified by TCAD simulations. At the same snapback voltage of 0.22 V and the liner energy transfer (LET) of 60 MeVcm2/mg conditions, the SEB threshold of RNB-IGBT is improved by 52 % compared to that of conventional RC-IGBT. This result indicates that the raised N-buffer layer of the RNB-IGBT can effectively reduce impact ionization, so it can suppress excessive heat concentration and avoid induce SEB.
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