Search

In the knowledge economy, innovation is playing an increasingly important role in urban sustainable development. Thus, how to strengthen the construction of innovation spaces has become a significant issue. Based on data from high-tech enterprises in the central urban area of Harbin, this study analyzes the distribution, agglomeration characteristics, and influencing factors of urban innovation spaces. The influencing factor index system was constructed based on four aspects: innovation support, service facilities, the social environment, and the natural environment. After analyzing these influencing factors through comparing the results obtained with an ordinary least squares (OLS) model and a geographical weighted regression (GWR) model, the GWR model was determined to have a better fitting effect and was thus used for further analysis. The findings are as follows: (1) Five closely related clusters of innovation spaces are identified. Innovation space has a significant agglomerating distribution pattern. (2) Overall, factors supporting innovation and transportation station factors have a positive effect on the agglomeration of innovation spaces, while natural environment factors have a negative effect on small innovation areas. (3) By region, the aggregation of innovation spaces in downtown areas is slightly negatively affected by service facilities, whereas those in the Harbin New District are mainly supported by policies and those in the Pingfang District are positively affected by the quantity of the labor force. Finally, based on the research results, some suggestions are put forward to promote the development of urban innovation spaces. This paper has certain guiding significance for optimizing and improving the construction and development of urban innovation spaces. [ABSTRACT FROM AUTHOR]

The optimization of the spatial structure of the city network is conducive to the scientific spatial distribution of industries and the promotion of coordinated regional development. This study selected the top 100 automobile enterprises in the Chinese stock market that belong to China's pillar industry, a total of 1455 headquarters and branches, to establish an enterprise matrix. Based on the ownership linkage model, the evolution characteristics of city networks in China from 2000 to 2020 are revealed, and the influential factors of city networks are discussed using the negative binomial regression model. The findings are as follows: (1) there are significant differences in the status of automobile cities, forming a "pyramid network" hierarchy. (2) The agglomeration area of automobile cities has formed the development region of "4 + 4 + 1". (3) The city network with hierarchical connections has formed a spatial structure of a "cross–cobweb" in the middle and "trapezoid–diamond" in the periphery. (4) Urban transportation conditions, the scientific research environment, the enterprise agglomeration economy, GDP per capita, and technological proximity positively impact the formation of a city network, but the total export–import volume has a negative impact. Overall, the government can use this study's results to formulate policies for the automotive industry and urban development. [ABSTRACT FROM AUTHOR]

In aquaculture, feeding intensity can directly reflect the appetite of fish, which is of great significance for guiding feeding and productive practice. However, most of the existing fish feeding intensity evaluation methods have problems of low observation efficiency and low objectivity. In this study, a fish feeding intensity evaluation method based on near-infrared machine vision was proposed to achieve an automatic objective evaluation of fish appetite. Firstly, a near-infrared image acquisition system was built by using near-infrared industrial camera. After a series of image processing steps, the gray level co-occurrence matrix was used to extract the texture feature variable information of the image, including contrast, energy, correlation, inverse gap and entropy. Then the data set were constructed by using these five feature variables as input vectors, and the support vector machine classifier was trained. Among them, the optimal penalty coefficient c and kernel function parameter g were selected by grid search. Finally, the trained images were used to classify the feeding images of fish. And ultimately, the evaluation of fish feeding intensity was realized. The results show that the accuracy of the evaluation could reach 87.78%. In addition, this method does not need to consider the impact of reflections, sprays and other factors on image processing results, so it has strong adaptability and can be used for automatic and objective evaluation of fish appetite, thus provide theoretical basis and methodological support for subsequent feeding decisions.

Objective: The pathogenesis of leukemia is complex and there are no effective diagnostic and prognostic indicators. Previous studies showed that microRNA-22 (miR-22) has altered expression level in multiple leukemia subtypes, which is associated with the survival outcomes of leukemia. Methods: According to the constituted retrieval strategy, eligible studies were included from January 2010 to November 2022 by searching database. The pooled Risk Ratio (RR) and 95% confidence intervals (CI) were used to study the relationship between miR-22 and survival. Stata12.0 was used for meta-analysis. Differential expression analysis was conducted based on expression profile of miRNA. Results: Four English articles were included containing a total of 215 leukemia patients. Data showed that the pooled RR for overall survival (OS) was 1.558 (95% CI: 1.197-2.028, P <.01). Subgroup analysis for OS of acute myeloid leukemia patients and the RFS of plasma cell leukemia patients were statistically significant with different expression levels of miR-22 (RR:1.495, 95%CI:1.141-1.958, P <.01 and RR:1.517, 95%CI:1.114-2.065, P <.01, respectively). Moreover, all data included had no significant heterogeneity and publication bias. Conclusions: miR-22 is associated with the survival outcome of leukemia patients suggesting that miR-22 may be a promising prognostic biomarker for this patient population, and the expression level of miR-22 in ALL patients down-regulated. [ABSTRACT FROM AUTHOR]

On the basis of a multi-length scale modeling, a mixture-averaged multi-component /multiphase micro-segregation model was proposed without pre-set function for the micro-scale solute profile. The model explains the effect of morphologies of solidifying phases and solid back diffusion (SBD) on segregation, and covers the two limiting solidification cases of Scheil and Lever-rule models. A commercial Thermo-Calc software package/database was linked to the algorithms via its TQ6-interface for instantaneous determination of the related thermodynamic data of the multi-component alloys. The influences of cooling rate and other parameters on the solidification path and micro-segregation behavior were numerically investigated by sample calculation of the ternary Al-Cu-Mg alloys. A parallel experimental investigation on Al-Cu-Si alloys solidified under different cooling conditions was conducted to validate the theoretical model. Reasonable agreements were gained between the predicted solidification paths and the measured results.

The vertical centrifugal-casting technique is widely used in the manufacture of various irregularlyshaped castings of advanced structural alloys with thin walls, complex shapes and/or large sizes. These castings are used in the increasing applications in aero-space/aviation industries, human teeth/bone repairs with nearnet shaped components, etc. In a vertically rotating casting system, the mold-filling processes of alloy melts, coupled with solidifi cation-heat transfer, may be much more complicated, because they are driven simultaneously by gravity, centrifugal and Coriolis forces. In the present work, an N-S/VOF-equations-based model, solved using a SOLA-VOF algorithm, under a rotating coordinate system was applied to numerically investigate the impacts of centrifugal and Coriolis forces on metallic melt mold-fi lling processes in different vertical centrifugal-casting configurations with different mold-rotation rates using an authors’ computer-codes system. The computational results show that the Coriolis force may cause remarkable variations in the fl ow patterns in the casting-part-cavities of a large horizontal-section area and directly connected to the sprue via a short ingate in a vertical centrifugalcasting process. A “turn-back” mold-filling technique, which only takes advantage of the centrifugal force in a transient rotating melt system, has been confi rmed to be a rational centrifugal-casting process in order to achieve smooth and layer-by-layer casting-cavities-fi lling control. The simulated mold-fi lling processes of Ti-6Al-4V alloy melt, in a vertical centrifugal-casting system with horizontally-connected plate-casting cavities, show reasonable agreement with experimental results from the literature.