Land application of animal manure
introduces large quantities of
ROX to the environment. ROX is highly water-soluble and easily adsorbs
on iron hydro(oxides). Photolysis of ROX in goethite (α-FeOOH)
suspensions was investigated under simulated sunlight irradiation.
The rate of ROX photodegradation in the presence of 2.2 mM α-FeOOH
was four times faster than that in pure water. The initial rate equation
for ROX photodegradation was determined to be r
init = (2.3 ± 0.4) × 10–4[ROX]0.5[α-FeOOH]1.1[H+]0.1 (μM·h–1) at initial pH values of 2.5–7.0,
ROX concentrations of 2.5–10.0 μM, and α-FeOOH
dosages of 0.6–2.2 mM. Approximately 6.2% of ROX underwent
direct photolysis ([ROX]0 = 5.0 μM, [α-FeOOH]0 = 2.2 mM), while the others were attributed to the indirect
photolysis introduced by α-FeOOH. The second-order rate constants
determined for the reactions between ROX and •OH
and O2
•– were 3.07 ± 0.09
× 109 and 2.08 ± 0.03 × 104 M–1·s–1, respectively. Inorganic
arsenics were the main arsenic-containing products, most of which
were adsorbed on α-FeOOH. Photodegradation pathways of ROX were
delineated based on the intermediates detected. The effects of water
constituents on photodegradation were evaluated. Results obtained
are helpful for better understanding the fate of ROX in aquatic environments.
Based on the features of Python and the situation of case-based teaching, this paper develops and implements a complete online Python teaching case library. The teaching contents of a Python programming were divided into ten parts: basic knowledge, three basic structures, functions and modules, object-oriented thinking, file and database programming, network and multithreading programming, image programming, web crawling, as well as data analysis and visualization. Each part was provided with several basic teaching cases. Following the idea of software engineering, our case library was designed based on ChaoXing, a famous online learning platform in China. The designed case library offers a clear path from data acquisition, data storage, data processing, to data visualization. It also provides a wealth of up-to-date and extensible contents, enabling learners to apply the knowledge to practice. Through application of the proposed case library, the students all achieved excellent performance, published innovative academic papers, and selected suitable topics for graduation thesis. The library also greatly promotes the abilities of students in computational thinking, programming level, and solving complex engineering problems.
With the help of the monotonicity trick, a nonautonomous Choquard
equations with general nonlinearity is studied and a nontrivial solution is
obtained.
In order to study the character of periodontal ligament cells (PDLCs) attaching on commercially pure titanium (cpTi) by morphology and metrology on the early stage (24 h), 1 x 10(5)/ml PDLCs in 2 ml culture medium were seeded on cpTi discs fixed in 24-well culture plates. Morphology of cell attachment was observed by contrast phase microscope, scanning electron microscope (SEM) and fluroscence microscopy. Cell adhesion was analyzed by MTT at 0.5, 1, 2, 4 h respectively. PDLCs could attach and spread on cpTi discs. SEM showed that PDLCs had pseudopod-like protuberance. PDLCs showed different attaching phases and reached saturation in cell number at 2 h. It was concluded that PDLCs had good biocompatibility with cpTi, and showed a regular and dynamic pattern in the process of attaching to cpTi.
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