Design of Hypervelocity-Impact Damage Evaluation Technique Based on Bayesian Classifier of Transient Temperature Attributes

With the rapid increasement of space debris on earth orbit, the hypervelocity-impact (HVI) of space debris can cause some serious damages to the spacecraft, which can affect the operation security and reliability of spacecraft. Therefore, the damage detection of the spacecrafts has become an urgent problem to be solved. In this paper, a method is proposed to detect the damage of spacecraft. Firstly, a variable-interval method is proposed to extract the effective information from the infrared image sequence. Secondly, in order to mine the physical meaning of the thermal image sequence, five attributes are used to construct a feature space. After that, a Naive Bayesian classifier is established to mine the information of different damaged areas. Then, a maximum interclass distance function is used choose the representative of each class. Finally, in order to visualize damaged areas, the Canny operator is used to extract the edge of the damage. In the experiment, ground tests are used to simulate hypervelocity impacts in space. Historical data of natural damaged material and artificial damaged material are used to build different classifiers. After that, the effective of classifiers is illustrated by accuracy, F-score and AUC. Then, two different types of materials are detected by proposed method, Independent Component Analysis (ICA) and Fuzzy C-means (FCM). The results show that the proposed method is more accurate than other methods

Synthesis Of Osmium Borides By Mechanochemical Method

Transition metal osmium borides were synthesized by mechanochemical method using high-energy ball-milling with Os (Osmium) and B (Boron) powders as raw materials. The formation process, reaction mechanism, and thermal stability of the mechochemically synthesized osmium borides were studied. Almost pure Os2B3 phase was obtained when the Os-to-B molar ratio was 1:2; while ReB2-type hexagonal OsB2 with a small amount of RuB2-type orthorhombic OsB2 was obtained when the Os-to-B molar ratio was 1:3. Stoichiometry OsB2 was obtained from boron rich starting mixture powders due to the B loss during the high-energy ball-milling process. It was also found that WC and osmium oxide were present as contaminants after ball milling for 40 hours. Heat treatment results revealed that the as-synthesized Os2B3 powders are thermally stable in flowing Ar up to 800°C, but a transformation from hexagonal to orthorhombic structure partially occurred for the OsB2 powders as low as 600°C

Construction of Green-Hydrogen Supply System in China: Reflections and Suggestions

Under the guidance of the carbon neutrality goal, energy production and consumption modes of China are shifting to be green and low-carbon, and the hydrogen energy supply system will be reshaped based on green hydrogen. Green hydrogen will become an important component of China’s new energy supply and consumption system. Strengthening the construction of a green-hydrogen supply system is conducive to the transformation of China’s energy production and consumption modes. This study explored the significant values for constructing the green-hydrogen supply system and analyzed the challenges faced by the construction, including (1) spatial mismatch between green hydrogen supply and demand, (2) temporal mismatch between green hydrogen production and consumption, and (3) mismatch between the green-hydrogen supply system and existing systems, mechanisms, and standards. To support the construction of the green-hydrogen supply system, key research directions include key basic issues of hydrogen storage and transportation, hydrogen storage and transportation technologies and equipment, and safety testing technologies of hydrogen storage and transportation equipment, thereby realizing the high-quality development of hydrogen storage and transportation. Moreover, the study proposed the integrated development of hydrogen energy and electrical power to construct the green-hydrogen supply system of China. Hydrogen storage and transportation is a key link that connects water-electrolytic hydrogen production and hydrogen consumption and is crucial for adjusting the spatial and temporal mismatch of green hydrogen supply and demand and for realizing flexible supply of green hydrogen. Therefore, we suggest that China should focus on top-level design and overall planning, improve infrastructures to address the spatial and temporal mismatches, conduct pilot demonstration to drive technological innovation, and improve the systems and mechanisms to optimize the development environment

Dynamic changes in marker components during the stir-frying of Pharbitidis Semen, and network analysis of its potential effects on nephritis

Introduction: Pharbitidis Semen (PS) has been widely used in traditional Chinese medicine to treat several diseases such as nephritis. PS is usually stir-fried to enhance its therapeutic efficacy before use in clinical practice. However, the changes in phenolic acids during stir-frying and the mechanisms of their therapeutic effects on nephritis are still unclear.Methods: Here, we studied the processing-induced chemical changes and elucidated the mechanism of PS in the treatment of nephritis. We determined the levels of the 7 phenolic acids in raw PS (RPS) and stir-fried PS (SPS) using high-performance liquid chromatography, analyzed the dynamic compositional changes during stir-frying, and used network analysis and molecular docking to predict and verify compound targets and pathways corresponding to nephritis.Results: The dynamic changes in the 7 phenolic acids in PS during stir-frying are suggestive of a transesterification reaction. Pathway analysis revealed that the targets of nephritis were mainly enriched in the AGE-RAGE, hypoxia-inducible factor-1, interleukin-17, and tumor necrosis factor signaling pathways among others. Molecular docking results showed that the 7 phenolic acids had good binding ability with the key nephritic targets.Discussion: The potential pharmaceutical basis, targets, and mechanisms of PS in treating nephritis were explored. Our findings provide a scientific basis for the clinical use of PS in treating nephritis

Dynamic ocular surface and lacrimal gland changes induced in experimental murine dry eye.

Dry eye disease can be a consequence of lacrimal gland insufficiency in Sjögren's Syndrome or increased tear film evaporation despite normal lacrimal gland function. To determine if there is a correlation between severity effects in these models and underlying pathophysiological responses, we compared the time dependent changes in each of these parameters that occur during a 6 week period. Dry eye was induced in 6-week-old female C57BL/6 mice by exposing them to an Intelligently Controlled Environmental System (ICES). Sixty mice were housed in ICES for 1, 2, 4 and 6 weeks respectively. Twelve were raised in normal environment and received subcutaneous injections of scopolamine hydrobromide (SCOP) 3 times daily for 5 days. Another sixty mice were housed in a normal environment and received no treatment. Corneal fluorescein staining along with corneal MMP-9 and caspase-3 level measurements were performed in parallel with the TUNEL assay. Interleukin-17(IL-17), IL-23, IL-6, IL-1, TNF-α, IFN-γ and TGF-β2 levels were estimated by real-time PCR measurements of conjunctival and lacrimal gland samples (LGs). Immunohistochemistry of excised LGs along with flow cytometry in cervical lymph nodes evaluated immune cell infiltration. Light and transmission electron microscopy studies evaluated LGs cytoarchitectural changes. ICES induced corneal epithelial destruction and apoptosis peaked at 2 weeks and kept stable in the following 4 weeks. In the ICES group, lacrimal gland proinflammatory cytokine level increases were much lower than those in the SCOP group. In accord with the lower proinflammatory cytokine levels, in the ICES group, lacrimal gland cytosolic vesicular density and size exceeded that in the SCOP group. ICES and SCOP induced murine dry eye effects became progressively more severe over a two week period. Subsequently, the disease process stabilized for the next four weeks. ICES induced local effects in the ocular surface, but failed to elicit lacrimal gland inflammation and cytoarchitectural changes, which accounts for less dry eye severity in the ICES model than that in the SCOP model

Matrix metalloproteinse 9 (MMP-9) expression profiles in each group.

<p>red, MMP9–positive; blue, DAPI-positive cells. (magnification:x20; scale bars: 50μm).</p

ICES Induced Corneal Epithelial Destruction.

<p>Corneal epithelial damage assessment by standard corneal fluorescein staining scores in ICES groups (E), the scopolamine-treated group (SCOP) and normal control group (N). *P < 0.05 versus the normal group (N).</p

Electron microscopic findings of the lacrimal gland acinus.

<p>A, Secretory vesicle (SV) accumulation in the normal group(N), Scale bars = 1um. Atrophic SVs in the scopolamine-treated group (SCOP).Excessive accumulation of SVs in the 1-week in the E group (E1).Excessive accumulation of SVs in the 2-week group (E2). Excessive accumulation of SVs in the 4-week group (E4).Excessive accumulation of SVs in the 6-week group (E6). B: SV diameter. Total number of vesicles examined/group: 159/N group，254/SCOP group, 249/E1 group, 341/E2 group, 302/E4 group and 485/E6 group (Mann-Whitney U test). C: Percent SV area per acinus. Total number of acini examined/group: 148/N group ，177/SCOP group, 223/E1 group, 270/E2 group, 339/E4 group and 549/E6 group (Mann-Whitney U test) # P<0.001 versus the SCOP group, ** p<0.001 versus the normal group(N).~ P<0.001 versus the the E2 group. Original magnification: X10000. Hollow arrow, Ductal lumen; Arrows, Nuclei; Triangle, SV.</p