Irradiance uniformity reshaping method for solar simulators based on computer-generated spatial filter films.

Irradiance uniformity is critical to the accuracy of photovoltaic device test results. Therefore, to post-correct the irradiance uniformity inherent in artificial lighting systems, a spatial irradiance filter scheme for film patterns is proposed based on the physical phenomenon of a positively related relationship between inkjet concentration and the transparency of the flexible film. The scheme first establishes the characteristic equation between the irradiance absorption and pattern grayscale values and then generates the spatial filtering pattern by utilizing the light intensity distribution to be calibrated, matrix operations, and bilinear interpolation. To evaluate its performance, an STM32 microprocessor-based irradiance distribution measurement system was developed and used to test and verify single lamp, planar array, and curved surface array light sources. The results reveal that the corrected irradiance uniformity improves by 15.5%, 24.01 %, and 13.11%, all of which achieve the Class A irradiance uniformity of the IEC 60904-9 standard.

Multi-scale feature pyramid fusion network for medical image segmentation.

PURPOSE: Medical image segmentation is the most widely used technique in diagnostic and clinical research. However, accurate segmentation of target organs from blurred border regions and low-contrast adjacent organs in Computed tomography (CT) imaging is crucial for clinical diagnosis and treatment. METHODS: In this article, we propose a Multi-Scale Feature Pyramid Fusion Network (MS-Net) based on the codec structure formed by the combination of Multi-Scale Attention Module (MSAM) and Stacked Feature Pyramid Module (SFPM). Among them, MSAM is used to skip connections, which aims to extract different levels of context details by dynamically adjusting the receptive fields under different network depths; the SFPM including multi-scale strategies and multi-layer Feature Perception Module (FPM) is nested in the network at the deepest point, which aims to better focus the network's attention on the target organ by adaptively increasing the weight of the features of interest. RESULTS: Experiments demonstrate that the proposed MS-Net significantly improved the Dice score from 91.74% to 94.54% on CHAOS, from 97.59% to 98.59% on Lung, and from 82.55% to 86.06% on ISIC 2018, compared with U-Net. Additionally, comparisons with other six state-of-the-art codec structures also show the presented network has great advantages on evaluation indicators such as Miou, Dice, ACC and AUC. CONCLUSION: The experimental results show that both the MSAM and SFPM techniques proposed in this paper can assist the network to improve the segmentation effect, so that the proposed MS-Net method achieves better results in the CHAOS, Lung and ISIC 2018 segmentation tasks.

Positioning of Prefabricated Building Components Based on BIM and Laser Image Scanning Technology in the Environment of Internet of Things.

In order to accurately locate the fabricated building components during assembly, the fabricated building components are monitored by laser scanning. At the same time, BIM Technology is proposed to carry out construction management in the construction process, realize safe site management and construction, reduce unnecessary mistakes of human operation, and improve construction quality. With the progress of computer technology, the emergence of the Internet of things has brought convenience to many fields. This research uses the application of phase ranging to carry out omnidirectional laser scanning on the fabricated building components, obtain the point cloud data, and use BIM Technology to simulate and analyze the building, establish the accurate positioning of building components, and prevent the offset phenomenon in the assembly process, so as to improve the construction quality and efficiency. In recent years, the integration of information technology into prefabricated buildings plays a vital role in the transformation and upgrading of China's construction industry. At the same time, it will also raise the information management level of prefabricated buildings to a new level. In order to improve the quality of building construction, this paper proposes a positioning method of prefabricated building components based on BIM Technology and laser scanning. On this basis, a complete architecture and detailed process application are established, and the promotion policies conducive to the development of intelligent construction of prefabricated buildings in BIM are put forward.

[Meta-analysis of Microbial Communities in the Activated Sludge of Wastewater Treatment Plants Under Different Climate Types].

Microbial communities in wastewater treatment plants(WWTPs) are very important for water purification in the context of public drinking water safety and environmental health. Therefore, it is necessary to explore the trends in microbial community structure and diversity in sewage treatment plants and their main environmental impact factors under different climates in China. Based on high-throughput sequencing techniques, a meta-analysis was conducted to screen the 16S rRNA genes in an open database. We analyzed the trends in microbial community structure and diversity in WWTPs under three climate types(Dwa, Cfa, and Cwa) in China. We then constructed cohesion models to examine the core microbial taxa and their interactions within the communities. We also used a piecewise structural equation model(PSEM) to examine the effects of different climate types on microbial community structure. The three climate types significantly affected the structure and diversity of the microbial communities, with patterns correlated with influent pH, mixed liquid temperature, conductivity, and nitrogen concentrations(P<0.05). Based on the PSEM analysis, the ß-diversity of the microbial communities was directly correlated with latitude, while α-diversity was indirectly correlated with latitude through conductivity and water temperature. Based on the cohesion modeling, microbial community stability was the highest under Dwa climate followed by the Cfa climate. This could be explained by a small subset of highly connected taxa capable of withstanding disturbance, indicating an important stability role. In contrast, the stability of the microbial communities under the Cwa climate was low, and no species with strong negative cohesion were observed. Overall, the structure, diversity, and stability of microbial community in WWTPs were found to be sensitive to climate, and the responsive mechanisms of α-diversity and ß-diversity with respect to latitude were distinct.

A novel assessment considering spatial and temporal variations of water quality to identify pollution sources in urban rivers.

It's vital to explore critical indicators when identifying potential pollution sources of urban rivers. However, the variations of urban river water qualities following temporal and spatial disturbances were highly local-dependent, further complicating the understanding of pollution emission laws. In order to understand the successional trajectory of water qualities of urban rivers and the underlying mechanisms controlling these dynamics at local scale, we collected daily monitoring data for 17 physical and chemical parameters from seven on-line monitoring stations in Nanfeihe River, Anhui, China, during the year 2018. The water quality at tributaries were similar, while that at main river was much different. A seasonal ''turning-back" pattern was observed in the water quality, which changed significantly from spring to summer but finally changed back in winter. This result was possibly regulated by seasonally-changed dissolved oxygen and water temperature. Linear mixed models showed that the site 2, with the highest loads of pollution, contributed the highest (ß = 0.316, P < 0.001) to the main river City Water Quality Index (CWQI) index, but site 5, the geographically nearest site to main river monitoring station, did not show significant effect. In contrast, site 5 but not site 2 contributed the highest (ß = 0.379, P < 0.001) to the main river water quality. Therefore, CWQI index was a better index than water quality to identify potential pollution sources with heavy loads of pollutants, despite temporal and spatial disturbances at local scales. These results highlight the role of aeration in water quality controlling of urban rivers, and emphasized the necessity to select proper index to accurately trace the latent pollution sources.