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The distribution of the flow field in the dust collector significantly affects its performance. The uniform distribution of the flow field is conducive to the dust reduction of the system, thus it requires the use of simulation software to simulate and analyze the flow field distribution of the dust removal system. This study used Fluent to simulate the flow field distribution of gaseous single-phase flow, gas-solid two-phase flow and gas-solid-liquid three-phase flow to investigate the effect of droplet particles on the flow field of the dust removal system, and the effect of droplet particles on the dust removal performance. Results show that the dust particles exerts minimal impact on the system flow field; the structure of the dust collector is found to be the major factor affecting the system flow field; the presence of droplets will increase the dust removal efficiency of the system; after the droplet particles are added, the dust movement disorder is enhanced, and the collision effect with the droplets is strengthened, which promotes the condensation of fine dust, improve the dust removal efficiency, but at the same time affects the stability of the system flow field and increases the resistance loss of the system.

Pearl River Delta is the most densely populated and urbanized area in China. As the pilot area of reform and opening up, Pearl River Delta takes the lead in its urbanization in China and represents the development trend of China's urbanization. Therefore, a great number and diversity of previous studies on urbanization in the Pearl River Delta warrant further review and reflection. This study focused on publications about urbanization in the Pearl River Delta from 1983 to 2020 in the collection of Chinese core journals and dissertations in the China Academic Journals Full-text Database (CNKI). The quantitative characteristics of published papers, the scientific cooperation network of core authors and institutions, research topics, and historical research hotspots were analyzed for different periods through bibliometrics and mapping knowledge domains based on CiteSpace. Results indicated that: (1) the number of publications of the relevant research showed an upward trend, which was divided into the following four stages: initial (1983-1991), exploratory (1992-2002), prosperity (2003-2011), and deep cultivation (2012-2020) stages. (2) The research institutions gradually expanded from south China universities, with Sun Yat-sen University emerging as the core to form a national network of research collaboration, and the scholar network has expanded from occasional collaboration to form a variety of cooperation networks within and across institutions. (3) In the evolution process of knowledge, research topics that scholars focused on included economic zone, rural urbanization, urban agglomeration, Guangdong-Hong Kong-Macao Greater Bay area, new-type urbanization, innovation, while other historical hotspots that scholars focused on included economic zone, new-type urbanization, and Guangdong-Hong Kong-Macao Greater Bay area. (4) The research showed the characteristics of policy and practice orientations, the continuous expansion of vision and scope, and the theoretical research stages evolving from lag to advance and then to synchronization. After the urbanization development stage of a metropolitan circle and urban agglomeration was jointly entered, the theoretical construction of localization was slightly insufficient, and that of the people-oriented urbanization mode was lacking. (5) Pearl River Delta entered the regional urbanization stage, with the metropolitan areas and urban agglomerations being the main body. The driving force of urbanization development shifted to scientific and technological innovation, while the development features shifted to intensive, high-quality, and people-oriented urbanization. Finally, this study argued that future studies on urbanization in Pearl River Delta should focus on the theoretical and practical pathways of the coordinated development of urban agglomeration in the Guangdong-Hong Kong-Macao Greater Bay area, innovation-driven development strategy, and people-oriented urbanization.

ObjectiveTo investigate the predictive value of preoperative neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), systemic inflammation response index (SIRI), and systemic immune inflammation index (SII) for early recurrence after liver resection in patients with hepatitis B-related hepatocellular carcinoma.MethodsA retrospective study was conducted on 162 patients who underwent hepatitis B-related hepatocellular carcinoma (HCC) resection between January 2013 and April 2016. The Youden index was utilized to calculate the optimal cut-off value. The Pearson Chi-square test was applied to analyze the relationship between inflammatory indexes and common clinical and pathological features. The Kaplan-Meier method and Log-Rank test were implemented to compare the recurrence-free survival rate within 2 years of the population. The Cox regression analysis was used to identify the risk factors for early postoperative recurrence.ResultsThe best cut-off values of SIRI, PLR, NLR and SII were 0.785, 86.421, 2.231 and 353.64, respectively. Tumor diameter, degree of tumor differentiation, vascular invasion, SIRI>0.785, PLR>86.421, NLR>2.231 and SII>353.64 were risk factors for early recurrence. Combining the above seven risk factors to construct a joint index, the AUC of the joint prediction model was 0.804. The areas under the ROC curves of SIRI, PLR, NLR, and SII were 0.659, 0.725, 0.680, and 0.723, respectively. There was no significant difference in the predictive ability between the single inflammatory index models, but the predictive performance of the joint prediction model was significantly higher than that of the single inflammatory index models. The patients with lower SIRI, PLR, NLR, SII and joint index value had longer recurrence-free survival within 2 years.ConclusionThe joint index CIP, constructed by combining preoperative SIRI, PLR, NLP and SII with pathological features, can better predict the early recurrence of HBV-related HCC patients after surgery, which is beneficial in identifying high-risk patients and assisting clinicians to make better clinical choices.

Super-resolution optical microscopy, which gives access to finer details of objects, is highly desired for fields of nanomaterial, nanobiology, nanophotonics, etc. Many efforts, including tip optimization and illumination optimization etc., have been made in both near-field and far-field super-resolution microscopy to achieve a spatial resolution beyond the diffraction limit. The development of vector light fields opens up a new avenue for super-resolution optical microscopy via special illumination modes. Cylindrical vector beam (CVB) has been verified to enable resolution improvement in tip-scanning imaging, nonlinear imaging, stimulated emission depletion (STED) microscopy, subtraction imaging, superoscillation imaging, etc. This paper reviews recent advances in CVB-based super-resolution imaging. We start with an introduction of the fundamentals and properties of CVB. Next, strategies for CVB based super-resolution imaging are discussed, which are mainly implemented by tight focusing, depletion effect, plasmonic nanofocusing, and polarization matching. Then, the roadmap of super-resolution imaging with CVB illumination in the past two decades is summarized. The typical CVB-based imaging techniques in fields of both near-field and far-field microscopy are introduced, including tip-scanning imaging, nonlinear imaging, STED, subtraction imaging, and superoscillation imaging. Finally, challenges and future directions of CVB-illuminated super-resolution imaging techniques are discussed.

In order to study the morphology, chemical composition, symbiotic relationship among major minerals and the typical embedding characteristics of the hydromagnesite from Bangor Lake in Tibet, polarizing microscope, scanning electron microscope, transmission electron microscope, electron probe and MLA mineral analysis system were used.The results indicate that the hydromagnesite is cryptocrystalline aggregate which consists of small crystal particles.The single crystal which has characteristic striation on the (001) is monoclinic plate-like.The hydromagnesite crystal usually grow into layered polysynthetic twin and contact twin along (100).Aragonite, dolomite and other carbonate minerals are often associated with hydromagnesite in disseminated symbiotic relationship in raw ores.It might be difficult to use physical mineral processing to get rid of them.

It is difficult for the conventional image compression method to achieve good compression effect in the underwater acoustic image (UWAI), because the UWAI has large amount of noise and low correlation between pixel points. In this paper, fractal coding is introduced into UWAI compression, and a fractal coding algorithm based on interest region is proposed according to the importance of different regions in the image. The application problems of traditional quadtree segmentation in UWAIs was solved by the range block segmentation method in the coding process which segmented the interest region into small size and the noninterest region into large size and balanced the compression ratio and the decoded image quality. This paper applies the classification, reduction codebook, and correlation coefficient matching strategy to narrow the search range of the range block in order to solve the problem of the long encoding time and the calculation amount of encoding process is greatly reduced. The experimental results show that the proposed algorithm improves the compression ratio and encoding speed while ensuring the image quality of important regions in the UWAI.

Abstract ZnO/HfO2:Eu nanocables were prepared by radio frequency sputtering with electrospun ZnO nanofibers as cores. The well-crystallized ZnO/HfO2:Eu nanocables showed a uniform intact core–shell structure, which consisted of a hexagonal ZnO core and a monoclinic HfO2 shell. The photoluminescence properties of the samples were characterized. A white-light band emission consisted of blue, green, and red emissions was observed in the nanocables. The blue and green emissions can be attributed to the zinc vacancy and oxygen vacancy defects in ZnO/HfO2:Eu nanocables, and the yellow–red emissions are derived from the inner 4f-shell transitions of corresponding Eu3+ ions in HfO2:Eu shells. Enhanced white-light emission was observed in the nanocables. The enhancement of the emission is ascribed to the structural changes after coaxial synthesis.

The functional relationship between the generation rate coefficient and temperature was developed for quantitative prediction of the temperature effect in this paper. The methane production of the landfill was predicted under the condition of the seasonal variation. The results showed that considering the temperature effect, the methane production is higher than the methane production without temperature effect of the 0.14×106 m3~0.28×106m3.With the depth increasing, the effect of the atmospheric temperature fluctuation on the temperature change of the landfill was weakened. The temperature has a significant effect on the methane production in the landfill. The temperature effect should be considered when simulate the long time effect of the landfill methane production.

According to the environment and work styles, the underwater monitoring devices can be divided into three type, fixed monitoring device, the floating monitoring device and mobile monitoring device. Floating monitoring platform is a new type of monitoring device of the floating monitoring device, which is mainly used for underwater video monitoring of pool. as the floating platform monitoring in water motion and hydrostatic characteristics are closely related, the influent of counterweight, weight distance and floating body diameter of the structure parameters on its hydrostatic characteristics and the natural periods for roll, pitch and heave should be considered, In this work, the floating body diameter influent most, the counterweight followed, and the structure parameters have different influence on the natural periods for roll, pitch and heave , it need to be analyzed according to the concrete structure parameters.