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A power-efficient 16-bit 1-MS/s successive approximation register (SAR) analog-to-digital converter (ADC) is presented in this paper. High-bit sampling makes the bridge capacitance in the digital-to-analog converter (DAC) a unit one, eliminating fractional capacitance mismatch. The high-precision comparator is composed of a four-stage preamplifier and a strong-arm latch, with auto-zeroing used to mitigate input offset further. Digital foreground calibration based on low-bit weight is implemented to correct DAC capacitance mismatch. The post-layout simulation results show that the core ADC achieves 95.61 dB SNDR and 105.1 dB SFDR with calibration, consuming 5.4 mW power under a 3.3 V supply voltage, corresponding to a Schreier figure of merit (FoM) of 175.3 dB. The ADC core area is 1.06 mm2 in the 180 nm CMOS technology. [ABSTRACT FROM AUTHOR]

In the context of the highly demanding trend of equitable and quality education, digital technology has outlined a blueprint for sharing resources across spatial and temporal boundaries and learner differences. The hybrid classroom implemented on university campuses during the pandemic demonstrates the tremendous shaping power of digital technology on teaching and learning across different groups, time, and space. This study investigates two types of learners, Clone Classroom and Global Hybrid Classroom at Tsinghua University, and finds that intrapersonal, interpersonal, and institutional dimensions of classroom climate all significantly affect learners' learning outcomes. However, the influences at the three dimensions differ in degree, with interpersonal factors outweighing institutional factors and institutional factors outweighing individual factors. Furthermore, in individual factors, information literacy and tech-assisted support in institutional factors have the weakest impact on learning outcomes; institutional factors mediate individual and interpersonal factors influencing higherorder cognition development. To avoid the pitfalls of techno-centrism, this study suggests promoting an insight of technology for humanity and embedding technology into teaching to better empower teacher development and student learning experience. [ABSTRACT FROM AUTHOR]

As the largest developing country, China has permanently attached great importance to cultivated land protection. However, due to the different rules of cultivated land identification in the second and third national land surveys, the cultivated land area in the two surveys has changed greatly. Some agricultural lands in the south, such as plantations, forests, grasslands, aquaculture ponds, etc., belonged to cultivated land during the second survey, but they were identified as non-cultivated land in the third national land survey. This change has led to a sharp reduction in the area of cultivated land in some places. In order to calculate the actual change in the area of cultivated land since the second survey and provide a reasonable basis for the standard of cultivated land protection, this paper takes Gaochun District, a developed area in China, as an example; interprets the images of the second national land survey period with the deep learning network HRNet; and compares the results with the second and third national land survey rules. The results show that the actual reduction of cultivated land in Gaochun District in the past ten years accounts for 35.1% of the reduction of cultivated land in the two land surveys, while the reduction of cultivated land caused by the change of cultivated land identification rules accounts for 64.9% of the reduction of cultivated land in the two land surveys, indicating that the significant reduction in local cultivated land was mainly caused by the changes in the rules, and these cultivated land reduction behaviors existed before the second survey. [ABSTRACT FROM AUTHOR]

The diverse value of rural areas has been gradually highlighted, and promoting the sustainable development of rural areas with the theoretical guidance of rural multifunction is the key to realizing rural revitalization. This study defined the concept of rural multifunction from the perspective of resident's demands and divided it into five main functions including rural agricultural production, nonagricultural production, living, ecological environment, and social security. By constructing the evaluation index system of rural multifunction, we analysed the spatial distribution characteristics of 160 villages of Jingjiang in Jiangsu Province. And functional combinations were identified to select targeted rural development paths oriented by balanced development of rural multifunction. The results showed the following. (1) The development of various rural functions in Jingjiang city was uneven, and agricultural production function still dominated. (2) The villages with strong agricultural production function were mainly concentrated in the northwest, while the villages with a high level of nonagricultural production function were mostly distributed in the industrial parks or around towns. There is still much room for improvement in social security function, especially in areas dominated by nonagricultural production. Nonagricultural production function had a negative effect on the ecological environment function, which is contrary to the agricultural production function. (3) Balanced development rather than equal development of rural functions should be pursued to achieve multifunctionality. Scientific guidance for the functional growth of villages in Jingjiang city and theoretical support for the microscale evaluation of rural multifunction and its application were provided by the research results. [ABSTRACT FROM AUTHOR]

The pattern for utilization of rural space is closely related to rural transformation development (RTD). The problem of rural space utilization is an important manifestation of the uncoordinated relationship between land use patterns and rural development status during a transformation period. Considering the rural space utilization issue, this article seeks to analyze the interaction mechanisms between land use transition (LUT) and rural spatial governance and then build a rural spatial governance analysis framework based on LUT. Also, the paper explores the internal relationship between rural spatial governance and rural vitalization and discusses the research prospective of the interaction. The study found that: (1) Rural space utilization has systemic problems such as limited development space, ill-defined ownership and poor organization, which have become important obstacles for rural development. (2) The uncoordinated relationship between LUT and RTD is an important reason for the dilemma surrounding rural space utilization. (3) The LUT provides a basis for determining the timing of rural spatial governance, specifying spatial governance objectives, and clarifying rural spatial governance methods. (4) The construction of a comprehensive analysis framework of "matter-ownership-organization" of rural space based on the LUT has created conditions for the orderly promotion of rural spatial governance. (5) Rural spatial governance which facilitates the integration of urban-rural development is an important foundation for rural vitalization. (6) Interaction analysis of LUT, RTD and rural spatial governance is conducive to facilitating research on the operational mechanism of rural regional systems and to expanding the research field of rural geography. [ABSTRACT FROM AUTHOR]

The study of multi-dimensional expansion of urban space (MEUS) addresses the laws of urban spatial expansion from all directions and angles. Using Nanjing as an example, this paper constructs multi-temporal, urban three-dimensional models based on RS and GIS technology and then conducts qualitative and quantitative analysis of MEUS using plot ratio change maps and MEUS quantitative index for built-up areas. Based especially on the concept of volume growth contribution rate, this paper analyzes the characteristics of MEUS in different stages. The results show that in 2000–2004, planar expansion played the main role, the internal potential development (IPD) intensity of the urban built-up areas was relatively large, and the volume growth contribution rate was low; in 2004–2008, planar expansion accelerated, and IPD slowed down; in 2008–2012, planar expansion slowed while IPD intensity increased; the contribution rates of volume growth of urban IPD for the three periods were 22.21%, 24.51% and 73.38%, respectively. This study expands the research perspective of urban spatial expansion, and the adopted methods are instructive and meaningful for MEUS research. In addition, the results of this study will deepen the understanding of MEUS laws and help improve scientific decision-making for urban planning and urban land use management. [ABSTRACT FROM AUTHOR]

An analysis of the evolution of urban three-dimensional morphology (EUTM) can comprehensively explore the processes and mechanisms of urban evolution and provide a basis for urban design and land use administration. Based on the three-dimensional model of urban built-up areas in two periods, this paper establishes a quantitative index system for the EUTM and discusses the methods of generating isoline maps for each index. The idea of making integrated partition map of urban three-dimensional morphology is developed according to a multidimensional feature space classification method. A quantitative analysis of the EUTM in Nanjing is carried out by using two types of maps. [ABSTRACT FROM AUTHOR]

In this paper, the artificial neural network (ANN) model was used to evaluate the degree of intensive urban land use in Nanjing City, China. The construction and application of the ANN model took into account the comprehensive, spatial and complex nature of urban land use. Through a preliminary calculation of the degree of intensive land use of the sample area, representative sample area selection and using the back propagation neural network model to train, the intensive land use level of each evaluation unit is finally determined in the study area. Results show that the method can effectively correct the errors caused by the limitations of the model itself and the determination of the ideal value and weights when the multifactor comprehensive evaluation is used alone. The ANN model can make the evaluation results more objective and practical. The evaluation results show a tendency of decreasing land use intensity from the core urban area to the periphery and the industrial functional area has relatively low land use intensity compared with other functional areas. Based on the evaluation results, some suggestions are put forward, such as transforming the mode of urban spatial expansion, strengthening the integration and potential exploitation of the land in the urban built-up area, and strengthening the control of the construction intensity of protected areas. [ABSTRACT FROM AUTHOR]

Using a population dataset of China, this study analyzes the spatial pattern of rural migration and urbanization and their coupling coordination relationship and investigates the causes of their spatial heterogeneity. Results show that rural migration and urbanization from 1978 to 2017 can be divided into three stages, i.e., the recovery and development stage, the stable and rapid development stage, and the stage of promoting the citizenization of the rural migrant population. From 2000 to 2010, counties with average annual growth rates of the ratio of rural migration (GRM) ranging from 0 to 5.00% showed a spatial pattern of ubiquitous distribution, while there were significant spatial inequalities in the average annual growth rates of the urbanization rate of the residential population (GUR) and hukou-registered population (GUH). Since urbanization and rural migration are two synergistic processes, coupling coordination degrees (CCDs) between GRM and GRU as well as GRM and GUH were generally between 0.60 and 0.80. Due to the gaps in socioeconomic development, spatial distance, and the policy system, they also showed regional heterogeneity, and there were notable differences in CCD between rural migration and urbanization of residential and hukou-registered populations. Finally, we propose that China should implement targeted and people-oriented measures to guide rural migration, promote new-type urbanization, and achieve integrated urban–rural development. [ABSTRACT FROM AUTHOR]

The spread of the novel coronavirus at the start of 2020 shocked higher education across China then around the rest of the world. To ensure sustainability of learning, this required an unprecedented shift from campus-based to emergency online education. This created an urgent need to learn more about the quality of online education, the provision of global education, and the transformation potential of universities. This paper analyses these matters, presenting insights from large-scale research conducted on a leading Chinese university, the first ever major research university to make this substantial transition. This research applied a mixed methods design, which combines quantitative and qualitative approaches. The results provide important insight into the nature, quality, and outcomes of online learning in major Asian research universities. They signal critical areas that require reform to ensure the sustainability of future higher education. [ABSTRACT FROM AUTHOR]

Food security requires a thorough understanding of the spatial characteristics of cultivated land changes on a global scale. In particular, the spatial heterogeneity of global cultivated land changes needs to be evaluated with high spatial resolution data. This study aims to analyse the spatial distribution of global cultivated land and the characteristics of its variation, by using GlobeLand30 data for 2000 and 2010 with a 30-m spatial resolution. The cultivated land percentage and rate of cultivated land use change are calculated based on 18 agro-ecological zones (AEZs), 32 geopolitical and socioeconomic regions, and 283 world regions. The results show that (1) more cultivated land is located in regions under a temperate climate and moderate moisture conditions; (2) the percentage of cultivated land is related to the gross domestic product (GDP) and population, while increases and decreases in cultivated land are related to the rural population, policy encouragement, urbanization, and economic development; and (3) the percentage of cultivated land and rate of land use change within an AEZ vary greatly due to the different socioeconomic conditions, and the values within a geopolitical area also vary, due to different natural conditions. [ABSTRACT FROM AUTHOR]