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In order to study the influence of flotation reagent system on coal slime flotation, the coal slime of Shuiyu Coal Washing Plant is taken as the research object.Based on the uniform experimental design(UED)method, the mathematical model between flotation effect and reagent dosage is established, and the effect of collector and frother dosage on flotation effect is investigated.The results show that the flotation effect of coal slime is only related to the amount of frother in a certain range of collector dosage; the optimal dosage of frother is 75 g/t, the appropriate dosage of collector is 130 g/t.Compared with the actual production dosage, under the conditions of 257 g/t collector and 143 g/t frother, and the ash content of clean coal kept unchanged, the yield of flotation clean coal is increased by 0.49 %, the combustible material recovery is increased by 0.50 %, the improvement index of flotation is increased by 0.17 %, the dosage of collector is reduced by 127 g/t, and the dosage of frother is reduced by 68 g/t.When the collector dosage is within a certain range, the frother dosage is the key factor affecting the flotation effect, and the appropriate frother dosage can significantly improve the coal slime separation effect.

The world's first total-body PET scanner with an axial field of view (AFOV) of 194 cm is now in clinical and research use at our institution. The uEXPLORER PET/CT system is the first commercially available total-body PET scanner. Here we present a detailed physical characterization of this scanner based on National Electrical Manufacturers Association (NEMA) NU 2-2018 along with a new set of measurements devised to appropriately characterize the total-body AFOV. Methods: Sensitivity, count-rate performance, time-of-flight resolution, spatial resolution, and image quality were evaluated following the NEMA NU 2-2018 protocol. Additional measurements of sensitivity and count-rate capabilities more representative of total-body imaging were performed using extended-geometry phantoms based on the world-average human height (∼165 cm). Lastly, image quality throughout the long AFOV was assessed with the NEMA image quality (IQ) phantom imaged at 5 axial positions and over a range of expected total-body PET imaging conditions (low dose, delayed imaging, short scan duration). Results: Our performance evaluation demonstrated that the scanner provides a very high sensitivity of 174 kcps/MBq, a count-rate performance with a peak noise-equivalent count rate of approximately 2 Mcps for total-body imaging, and good spatial resolution capabilities for human imaging (≤3.0 mm in full width at half maximum near the center of the AFOV). Excellent IQ, excellent contrast recovery, and low noise properties were illustrated across the AFOV in both NEMA IQ phantom evaluations and human imaging examples. Conclusion: In addition to standard NEMA NU 2-2018 characterization, a new set of measurements based on extending NEMA NU 2-2018 phantoms and experiments was devised to characterize the physical performance of the first total-body PET system. The rationale for these extended measurements was evident from differences in sensitivity, count-rate-activity relationships, and noise-equivalent count-rate limits imposed by differences in dead time and randoms fraction between the NEMA NU 2 70-cm phantoms and the more representative total-body imaging phantoms. Overall, the uEXPLORER PET system provides ultra-high sensitivity that supports excellent spatial resolution and IQ throughout the field of view in both phantom and human imaging.

The world's first 194-cm-long total-body PET/CT scanner (uEXPLORER) has been built by the EXPLORER Consortium to offer a transformative platform for human molecular imaging in clinical research and health care. Its total-body coverage and ultra-high sensitivity provide opportunities for more accurate tracer kinetic analysis in studies of physiology, biochemistry, and pharmacology. The objective of this study was to demonstrate the capability of total-body parametric imaging and to quantify the improvement in image quality and kinetic parameter estimation by direct and kernel reconstruction of the uEXPLORER data. Methods: We developed quantitative parametric image reconstruction methods for kinetic analysis and used them to analyze the first human dynamic total-body PET study. A healthy female subject was recruited, and a 1-h dynamic scan was acquired during and after an intravenous injection of 256 MBq of 18F-FDG. Dynamic data were reconstructed using a 3-dimensional time-of-flight list-mode ordered-subsets expectation maximization (OSEM) algorithm and a kernel-based algorithm with all quantitative corrections implemented in the forward model. The Patlak graphical model was used to analyze the 18F-FDG kinetics in the whole body. The input function was extracted from a region over the descending aorta. For comparison, indirect Patlak analysis from reconstructed frames and direct reconstruction of parametric images from the list-mode data were obtained for the last 30 min of data. Results: Images reconstructed by OSEM showed good quality with low noise, even for the 1-s frames. The image quality was further improved using the kernel method. Total-body Patlak parametric images were obtained using either indirect estimation or direct reconstruction. The direct reconstruction method improved the parametric image quality, having a better contrast-versus-noise tradeoff than the indirect method, with a 2- to 3-fold variance reduction. The kernel-based indirect Patlak method offered image quality similar to the direct Patlak method, with less computation time and faster convergence. Conclusion: This study demonstrated the capability of total-body parametric imaging using the uEXPLORER. Furthermore, the results showed the benefits of kernel-regularized reconstruction and direct parametric reconstruction. Both can achieve superior image quality for tracer kinetic studies compared with the conventional indirect OSEM for total-body imaging.

Reducing carbon emissions from the transport sector is essential for realizing the carbon neutrality goal in China. Despite substantial studies on the influence of urban form on transport CO2 emissions, most of them have treated the effects as a linear process, and few have studied their nonlinear relationships. This research focused on 274 Chinese cities in 2019 and applied the gradient-boosting decision tree (GBDT) model to investigate the nonlinear effects of four aspects of urban form, including compactness, complexity, scale, and fragmentation, on urban transport CO2 emissions. It was found that urban form contributed 20.48% to per capita transport CO2 emissions (PTCEs), which is less than the contribution of socioeconomic development but more than that of transport infrastructure. The contribution of urban form to total transport CO2 emissions (TCEs) was the lowest, at 14.3%. In particular, the effect of compactness on TCEs was negative within a threshold, while its effect on PTCEs showed an inverted U-shaped relationship. The effect of complexity on PTCEs was positive, and its effect on TCEs was nonlinear. The effect of scale on TCEs and PTCEs was positive within a threshold and negative beyond that threshold. The effect of fragmentation on TCEs was also nonlinear, while its effect on PTCEs was positively linear. These results show the complex effects of the urban form on transport CO2 emissions. Thus, strategies for optimizing urban form and reducing urban transport carbon emissions are recommended for the future. [ABSTRACT FROM AUTHOR]

Numerous studies estimating transport CO2 emissions in developing countries were on the large scales and few provided high-resolution mapping of transport CO2 emissions from different transport modes according to their respective distribution and diffusion patterns. This study proposed a hybrid method for high-resolution mapping of transport CO2 emissions in metropolitan regions, and applied it to the Beijing–Tianjin–Hebei (BTH) region of China during 2000-2019. The results indicate that: (1) The transport CO2 emissions in the BTH region increased rapidly, of which road transport carbon emissions accounting for approximately 80%, air transport carbon emissions accounting for nearly 20%, railway and water transport accounted for a relatively small proportion. (2) For the transport CO2 emission structure from 2000 to 2019, road transport was still the main source, but its proportion has decreased since recent years, which air transport became the second largest source of emissions and had greater impact on Beijing and Tianjin. (3) The transport carbon emission hot spots were mainly located in Beijing and kept shrinking, while the cold spots were mainly located in the southern part of Hebei Province and kept expanding. (4) The decoupling relationship between county-level transport carbon emissions and economic growth changed from weak decoupling to expansive negative decoupling, showing a non-ideal development in the BTH region. Overall, this study revealed the spatiotemporal characteristics of transport CO2 emissions in the BTH region, based on which specific carbon reduction strategies could be promoted to facilitate sustainable low-carbon transport development in metropolitan regions in developing countries. [ABSTRACT FROM AUTHOR]

Collecting and mining customer consumption data is crucial to assess customer value and predict customer consumption behaviors. This paper proposes a new procedure, based on an improved random forest model, by adding a new indicator joining the RFMS-based method to a K-means algorithm with the entropy weight method applied in computing the customer value index, classifying customers to different categories, and then constructing a consumption forecasting model whose RMSE is the smallest in all kinds of data mining models. The results show that identifying customers by this improved RMF model and customer value index facilitates customer profiling, and forecasting customer consumption enables the development of more precise marketing strategies. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the study was to determine a faster PET acquisition protocol for a total-body PET/CT scanner by assessing the image quality that is equivalent to a conventional digital PET/CT scanner from both a phantom and a clinical perspective. Methods: A phantom study using a NEMA/IEC NU-2 body phantom was first performed in both a total-body PET/CT (uEXPLORER) and a routine digital PET/CT (uMI 780), with a hot sphere to background activity concentration ratio of 4:1. The contrast recovery coefficient (CRC), background variability (BV), and recovery coefficient (RC: RCmax and RCmean) were assessed in the uEXPLORER with different scanning durations and reconstruction protocols, which were compared to those acquired from the uMI 780 with clinical acquisition settings. The coefficient of variation (COV) of the uMI 780 with clinical settings was calculated and used as a threshold reference to determine the optimized scanning duration and reconstruction protocol for the uEXPLORER. The obtained protocol from the phantom study was subsequently tested and validated in 30 oncology patients. Images acquired from the uMI 780 with 2–3 min per bed position were referred as G780 and served as the reference for comparison. All PET raw data from the uEXPLORER were reconstructed using the data-cutting technique to simulate a 30-s, 45-s, or 60-s acquisition duration, respectively. The iterations were 2 and 3 for the uEXPLORER, referred as G30s_3i, G45s_2i, G45s_3i, G60s_2i, and G60s_3i, respectively. A 5-point Likert scale was used in the qualitative analysis to assess the image quality. The image quality was also evaluated by the liver COV, the lesion target-to-background ratio (TBR), and the lesion signal-to-noise ratio (SNR). Results: In the phantom study, CRC, BV, RCmax, and RCmean in the uEXPLORER with different scanning durations and reconstruction iterations were compared with those in the uMI 780 with clinical settings. A minor fluctuation was found among different scanning durations. COV of the uMI 780 with clinical settings was 11.6%, and a protocol with a 30–45-s scanning duration and 2 or 3 iterations for the uEXPLORER was found to provide an equivalent image quality as the uMI 780. An almost perfect agreement was shown with a kappa value of 0.875. The qualitative score of the G30s_3i in the uEXPLORER was inferior to the G780 reference (p = 0.001); however, the scores of other groups in the uEXPLORER with a 45-s and above acquisition time were higher than the G780 in the uMI 780. In quantitative analysis, the delay time between the two scans in the two orders was not significantly different. There was no significant difference of the liver COV between the G780 and G30s_3i (p = 0.162). A total of 33 lesions were analyzed in the clinical patient study. There was no significant difference in lesion TBR between the reference G780 and the G45s_2i obtained from the uEXPLORER (p = 0.072), while the latter showed a higher lesion SNR value compared to that in uMI 780 with clinical settings (p < 0.001). Conclusions: This study showed that a fast PET protocol with a 30–45-s acquisition time in the total-body uEXPLORER PET/CT can provide an equivalent image quality as the conventional digital uMI 780 PET/CT with longer clinical acquisition settings. [ABSTRACT FROM AUTHOR]

Angiogenesis plays an important role in tumor growth and expansion, which makes it one of the most critical subjects in oncologic research. Angiogenesis can be imaged with photoacoustic microscopy (PAM), however the lateral resolution deteriorates significantly out of focus. Virtual-point-detector-based synthetic aperture focusing technique (SAFT) combined with the coherence weighting factor (CF) can alleviate the blurring, at a cost of anisotropy of resolution. In this study, a two-dimensional SAFT with CF was investigated to improve resolution and yield lateral resolution isotropy simultaneously. In a phantom study, two carbon fibers with a diameter of 6 μm fixed perpendicularly to each other were imaged with PAM developed in our laboratory. In the depth range of 0.6 mm near the focal spot, the best resolution processed with one-dimensional (1D) SAFT is 40 μm better than that processed with two-dimensional (2D) SAFT. However, the maximum difference in lateral resolution between the z-x and z-y planes is about 15 μm processed with 2D SAFT, while it is 145 μm processed with 1D SAFT. Furthermore, the 2D SAFT increased the signal-to-noise ratio (SNR) by up to 8 dB higher than 1D SAFT at an imaging depth of 700 μm below the focal spot. Finally, in vivo imaging of the dorsal subcutaneous microvasculature of a mouse was used to validate the improved performance of 2D SAFT. [ABSTRACT FROM AUTHOR]