6 research outputs found
An Improved Dynamic Contact Model for Mass–Spring and Finite Element Systems Based on Parametric Quadratic Programming Method
<div><p>Abstract An improved dynamic contact model for mass-spring and finite element systems is proposed in this paper. The proposed model avoids the numerical troubles of spurious high-frequency oscillations for mass-spring and finite element systems in dynamic contact problems by using the parametric quadratic programming technique. The iterative process for determination of contact states are not required for each time step in the proposed method, as the contact states are transformed into the base exchanges in the solution of a standard quadratic programming problem. The proposed methodology improves stability and has good convergence behavior for dynamic contact problems. Numerical results demonstrate the validity of the proposed method.</p></div
Occurrence and Temporal Trends of Benzotriazole UV Stabilizers in Mollusks (2010–2018) from the Chinese Bohai Sea Revealed by Target, Suspect, and Nontarget Screening Analysis
Benzotriazole UV stabilizers (BZT-UVs),
including 2-(3,5-di-tert-amyl-2-hydroxyphenyl)benzotriazole
(UV-328) that is
currently under consideration for listing under the Stockholm Convention,
are applied in many commodities and industrial products. However,
limited information is available on the interannual variation of their
environmental occurrence. In this study, an all-in-one strategy combining
target, suspect, and nontarget screening analysis was established
to comprehensively explore the temporal trends of BZT-UVs in mollusks
collected from the Chinese Bohai Sea between 2010 and 2018. Significant
residue levels of the target analytes were determined with a maximum
total concentration of 6.4 Ă— 103 ng/g dry weight.
2-(2-Hydroxy-3-tert-butyl-5-methyl-phenyl)-5-chloro-benzotriazole
(UV-326), 5-chloro-2-(3,5-di-tert-butyl-2-hydroxyphenyl)benzotriazole
(UV-327), and 2-(2-hydroxy-5-methylphenyl) benzotriazole (UV-P) were
the predominant analogues, and UV-328 was the most frequently detected
BZT-UV with a detection frequency (DF) of 87%. Whereas five biotransformation
products and six impurity-like BZT-UVs were tentatively identified,
their low DFs and semi-quantified concentrations suggest that the
targeted analytes were the predominant BZT-UVs in the investigated
area. A gradual decrease in the total concentrations of BZT-UVs was
observed, accompanied by downward trends of the abundant compounds
(e.g., UV-326 and UV-P). Consequently, the relative abundance of UV-327
increased because of its consistent environmental presence. These
results suggest that continuous monitoring and risk assessment of
BZT-UVs other than UV-328 are of importance in China
An Integrated Workflow Assisted by In Silico Predictions To Expand the List of Priority Polycyclic Aromatic Compounds
The limited information in existing mass spectral libraries
hinders
an accurate understanding of the composition, behavior, and toxicity
of organic pollutants. In this study, a total of 350 polycyclic aromatic
compounds (PACs) in 9 categories were successfully identified in fine
particulate matter by gas chromatography high resolution mass spectrometry.
Using mass spectra and retention indexes predicted by in silico tools
as complementary information, the scope of chemical identification
was efficiently expanded by 27%. In addition, quantitative structure–activity
relationship models provided toxicity data for over 70% of PACs, facilitating
a comprehensive health risk assessment. On the basis of extensive
identification, the cumulative noncarcinogenic risk of PACs warranted
attention. Meanwhile, the carcinogenic risk of 53 individual analogues
was noteworthy. These findings suggest that there is a pressing need
for an updated list of priority PACs for routine monitoring and toxicological
research since legacy polycyclic aromatic hydrocarbons (PAHs) contributed
modestly to the overall abundance (18%) and carcinogenic risk (8%).
A toxicological priority index approach was applied for relative chemical
ranking considering the environmental occurrence, fate, toxicity,
and analytical availability. A list of 39 priority analogues was compiled,
which predominantly consisted of high-molecular-weight PAHs and alkyl
derivatives. These priority PACs further enhanced source interpretation,
and the highest carcinogenic risk was attributed to coal combustion
An Integrated Workflow Assisted by In Silico Predictions To Expand the List of Priority Polycyclic Aromatic Compounds
The limited information in existing mass spectral libraries
hinders
an accurate understanding of the composition, behavior, and toxicity
of organic pollutants. In this study, a total of 350 polycyclic aromatic
compounds (PACs) in 9 categories were successfully identified in fine
particulate matter by gas chromatography high resolution mass spectrometry.
Using mass spectra and retention indexes predicted by in silico tools
as complementary information, the scope of chemical identification
was efficiently expanded by 27%. In addition, quantitative structure–activity
relationship models provided toxicity data for over 70% of PACs, facilitating
a comprehensive health risk assessment. On the basis of extensive
identification, the cumulative noncarcinogenic risk of PACs warranted
attention. Meanwhile, the carcinogenic risk of 53 individual analogues
was noteworthy. These findings suggest that there is a pressing need
for an updated list of priority PACs for routine monitoring and toxicological
research since legacy polycyclic aromatic hydrocarbons (PAHs) contributed
modestly to the overall abundance (18%) and carcinogenic risk (8%).
A toxicological priority index approach was applied for relative chemical
ranking considering the environmental occurrence, fate, toxicity,
and analytical availability. A list of 39 priority analogues was compiled,
which predominantly consisted of high-molecular-weight PAHs and alkyl
derivatives. These priority PACs further enhanced source interpretation,
and the highest carcinogenic risk was attributed to coal combustion
Graded-Band-Gap Zinc–Tin Oxide Thin-Film Transistors with a Vertically Stacked Structure for Wavelength-Selective Photodetection
Filter-free
wavelength-selective photodetectors have garnered significant
attention due to the growing demand for smart sensors, artificial
intelligence, the Internet of Everything, and so forth. However, the
challenges associated with large-scale preparation and compatibility
with complementary metal-oxide-semiconductor (CMOS) technology limit
their wide-ranging applications. In this work, we address the challenges
by constructing vertically stacked graded-band-gap zinc–tin
oxide (ZTO) thin-film transistors (TFTs) specifically designed for
wavelength-selective photodetection. The ZTO thin films with various
band gaps are fabricated via atomic layer deposition (ALD) by varying
the ALD cycle ratios of zinc oxide (ZnO) and SnO2. The
ZTO film with a small Sn ratio exhibits a decreased band gap, and
the resultant TFT shows a degraded performance, which can be attributed
to the Sn4+ dopant introducing a series of deep-state energy
levels in the ZnO band gap. As the ratio of Sn increases further,
the band gap of the ZTO also increases, and the mobility of the ZTO
TFT increases up to 30 cm2/V s, with a positive shift of
the threshold voltage. The photodetectors employing ZTO thin films
with distinct band gaps show different spectral responsivities. Then,
vertically stacked ZTO (S-ZTO) thin films, with gradient band gaps
increasing from the bottom to the top, have been successfully deposited
using consecutive ALD technology. The S-ZTO TFT shows decent performance
with a mobility of 18.4 cm2/V s, a threshold voltage of
0.5 V, an on–off current ratio higher than 107,
and excellent stability under ambient conditions. The resultant S-ZTO
TFT also exhibits obviously distinct photoresponses to light at different
wavelength ranges. Furthermore, a device array of S-ZTO TFTs demonstrates
color imaging by precisely reconstructing patterned illuminations
with different wavelengths. Therefore, this work provides CMOS-compatible
and structure-compact wavelength-selective photodetectors for advanced
and integrable optoelectronic applications
Additional file 1 of GBDT_KgluSite: An improved computational prediction model for lysine glutarylation sites based on feature fusion and GBDT classifier
Additional file 1: Table S1. Performance of different feature representation