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As a key index to evaluate whether a city is attractive or has a healthy, comprehensive, and sustainable development potential, urban vitality is critical to the future development and construction of a city. Exploring the mechanism of how the built environment influences urban vitality from the perspective of urban morphology can be conducive to future urban space planning and design and can provide city planners with quantitative and scientific decision-making support. This study uses urban POI, cellular signaling, and nighttime light remote sensing data from Shenzhen to measure its cultural, social, and economic vitality, which constitutes a comprehensive vitality assessment of the city. Spatial features of these urban vitalities were then analyzed to further illustrate their distribution patterns. Using Bivariate Moran's I method, the spatial autocorrelations between economic, social, and cultural vitality were calculated. From the five dimensions of Density, Design, Diversity, Distance to Transit, and Destination Accessibility, the 5D detection index system was constructed to measure the urban built environment. This study also used GeoDetector to detect and analyze the spatial differentiation between various built environmental factors and comprehensive, economic, social, and cultural vitality and to explore the mechanism of the influence of the built environment on urban vitality. The results show that: 1) The spatial distribution of comprehensive vitality is extremely uneven in Shenzhen, with a higher vitality in the southern and western regions of Shenzhen city and a lower vitality in the northern and eastern regions. Areas with higher comprehensive vitality usually developed along the main roads and metro lines and are distributed in strips along the coastline of central-southern and western Shenzhen. The high-value areas of the urban comprehensive vitality center are primarily concentrated in city- or district-level commercial centers, and employment centers. Comprehensive vitality in Shenzhen reflects social vitality. 2) Urban comprehensive, economic, social, and cultural vitality are significantly affected by the built environment, as indicated by the 5D system. High POI and building density, average building floors, and land use entropy, have significant positive impacts on urban vitality. However, residential population density did not have a significant impact on each aspect of urban vitality. 3) Some interactions between built environment factors had a greater impact on urban comprehensive vitality, such as residential population density, road network density, land use entropy, and road network density. Overall, the interaction between building density, average building floors, land use entropy, and other factors, have a more positive impact on each aspect of urban vitality. 4) The presentation of urban comprehensive vitality is the result of multiple dimensions and factors. In the influencing mechanism of urban comprehensive vitality, building density and average building floors were the fundamental factors. POI density and land use entropy were the direct driving factors. Residential population density was an inducing factor. Distance from the administrative center, intersection density, road network density, metro station density, and bus station density were adjustive factors. The research results therefore provide valuable suggestions for the optimal allocation of resources and the rational layout of urban functional facilities in Shenzhen.

The consumer service industry directly provides residents with material and spiritual living consumption services and products to meet residents' consumption needs. The reasonable spatial layout of the consumer service industry is of great significance for improving residents' quality of living, optimizing the urban spatial structure, and alleviating urban problems. Based on consumer service point of interest (POI) data, mobile phone signaling data, and population data from Shenzhen, using the nearest neighbor index, kernel density, and entropy index methods, this study analyzes the spatial pattern of the overall and different types of consumer service industry as well as the spatial characteristics of the degree of mixing in the consumer service industry in Shenzhen. Using the Geodetector method, this study also detects the impacts of seven factors, including population, traffic, economy, and space dimensions, on the overall and different types of consumption service industry as well as analyzing the impacts of population age structure on the spatial pattern of this industry and its types. This study is expected to provide a theoretical and decision-making basis for urban planning and development in Shenzhen and other cities. The results show that: 1) The spatial distribution of the consumer service industry in Shenzhen is unbalanced and is concentrated in the central and western regions. The consumer service industry presents the spatial characteristics of two core areas and three belt areas. The two core areas are the Dongmen business area in Luohu District and the Huaqiangbei business area in Futian District. The three belt areas consist of the Luohu-Futian belt, Nanshan-Baoan belt, and Longhua belt. The spatial distribution of the consumer service industry has developed along strips and is mainly concentrated in the areas around the main roads and rail lines. 2) The spatial agglomeration characteristics of the overall and different types of consumer service industry are remarkable and differentiated in Shenzhen. The spatial distribution characteristics of most types of consumer services are similar to those of the overall consumer service industry. The development of industry in some areas has resulted in differences in the spatial distribution of certain categories. 3) The balance of the consumer service industry is better in the Luohu, Futian, Nanshan District and worse in the other Districts. The high balanced areas are the edge areas outside the two core areas, rather than the two core areas with the highest POI density. 4) Population density factors are the most important factors affecting the spatial pattern of the consumer service industry, followed by traffic factors. The influence of economic and spatial factors is relatively low. 5) The population of people aged 19-35 has the greatest impact on the density of the consumer service industry. Age groups have different impacts on the spatial distribution of different types of consumer service industries because of specific needs. These results are consistent with the spatial planning of urban functional zoning and industrial development layout in the Shenzhen Urban Master Plan (2010-2020). Combining these results and current urban development activities, this study provides suggestions for optimizing the spatial layout of the consumer service industry in Shenzhen.

Wearable sweat biosensors have gained attention due to their potential for non-invasive health monitoring. However, practical applications still face challenges in integrating multiplex sensors primarily due to sweat accumulation, complex microfluidic preparation processes, and degradability of substrate materials. In this study, a multiplex sweat sensor based on leather fluidic transport is proposed. The pre-treated leather exhibits favorable hydrophilicity, air permeability, and biocompatibility. Furthermore, high sensitivity and stability multiplex sensor electrodes for pH, chloride, potassium, and sodium ions have been integrated into the leather-based fluid transport to fabricate an integrated wearable sweat device. By enabling sweat analysis compatible with routine and daily activities, the integrated wearable sweat device achieves continuous and long-term monitoring of body physiology. [ABSTRACT FROM AUTHOR]

Global warming caused by massive carbon dioxide emissions can lead to a chain of ecological disasters. As one of the main sources of carbon emissions, transportation is of great significance, and the evaluation of its connections with carbon emissions is necessary to achieve "carbon neutrality". Taking Beijing as an example, this study evaluated traffic efficiency (TE) by utilizing principal component analysis and fuzzy comprehensive evaluation. Using the Tapio decoupling model and coupling coordination degree model, the corresponding relationship between urban low carbon level (LCL) and TE was explored. The results showed the following: (1) The total carbon emission (CE) level exhibited fluctuating variation from increasing to decreasing. The carbon emission intensity (CEI) continued to slow down, and the rapid growth of population density played a key role in low-carbon development. (2) The traffic operations continually showed a positive trend in development. TE increased from a step-like to a slow shape, until it declined in 2020 due to the pandemic. (3) TE and LCL both developed from low coordination to an extreme level of coordination. Per capita carbon emission (CEP) and TE presented an inverted U-shaped curve; meanwhile, with increases in TE, the decline in CEI slowed. In addition, the weak decoupling of TE changed to become strong, due to CE and CEP, and maintained a strong decoupling state from CEI. (4) There is a necessity for the rational planning of land use for transportation infrastructure, the encouragement of a combination of public and private transportation, and the strengthening of the maintenance of the relative infrastructure and the management of traffic behaviors to attain a win–win situation. The results provide a reference for optimizing the traffic structure to achieve "carbon neutrality". [ABSTRACT FROM AUTHOR]

As a new type of backfill material, Self-compacting solidified soil (SCSS) takes the abandoned slurry of cast-in-place piles after dewatering and reduction as the main raw material, which brings a problem of coordinating the working performance with the mechanical property under the condition of high mobility. In this paper, hydroxypropyl methyl cellulose (HPMC) and metakaolin were introduced as additives to solve this problem. First, the workability and mechanical properties of SCSS were regulated and optimized by means of the water seepage rate test, the flowability test, and the unconfined compressive strength test. Second, this study also used X-ray diffraction (XRD) and scanning electron microscopy (SEM) to investigate the effects of HPMC and metakaolin on the physical phase and microstructure of SCSS. In this way, the results showed that there was a significant impact on the flowability of SCSS, that is, when the dosage reached 0.3%, the water seepage rate of SCSS was reduced to less than 1%, and the compressive strength at 7 days reached its peak. At the same time, HPMC weakened the strength growth of SCSS in the age period of 7 days to 14 days. However, the addition of metakaolin promoted its compressive strength. XRD analysis showed that the additives had no significant effects on the physical phases. And, from the SEM results, it can be seen that although the water-retaining effect of HPMC makes hydration of cement more exhaustive, more ettringite (AFt) can be observed in the microstructure. In addition, it can be observed that the addition of metakaolin can generate more hydrated calcium silicate (C-S-H) due to the strong surface energy possessed by metakaolin. As a result of the above factors, SCSS filled the voids between particles and improved the interface structure between particles, thus enhanced the compressive strength. [ABSTRACT FROM AUTHOR]