(Section A: Planning Strategies and Design Concepts)

This paper uses four years of ecosystem classification data, from 2000, 2005, 2010 and 2015, to analyse the spatiotemporal variation characteristics of the ecosystems of counties and cities in the Min Delta urban agglomeration over 15 years across four aspects, including changes in the ecosystem area for each period, a transfer matrix of the counties and cities, the comprehensive dynamic ecosystem index, and the forces driving these changes. The results show that: (1) from 2000 to 2015, the total area of farmland, forest and shrub ecosystems in the Min Delta urban agglomeration decreased, while the total area of urban, wetland and grassland ecosystems has increased. There are spatiotemporal differences and patterns in the area change and transfer of various ecosystems. The series of scales and proportion of ecosystem types in the counties and cities of the Min Triangle show that there is a two-way transfer between farmland and urban ecosystems. In addition, there are spatiotemporal differences in the transfer of these two ecosystems. Forest ecosystems are transferred into farmland, urban and grassland ecosystems at different levels. In the eastern part of the Min Triangle, wetlands are mostly transferred to urban ecosystems, and the western regions are mostly transferred to forests and farmland. (2) For the comprehensive dynamic index of the Min Delta urban agglomeration, from 2000 to 2015, the degree of ecosystem dynamics was higher in each period than the previous, and the dynamics in the eastern and central parts were higher than those in the west and south for the same period. From 2000 to 2005, the comprehensive dynamic index was below 0.2%. The dynamic index of Longhai in Xiamen and Zhangzhou increased significantly from 2005 to 2010 from that of the previous period, and their values all exceeded 0.9%. From 2010 to 2015, the area with a large change in the dynamic index expanded to the east and south from the central area of Xiamen. The dynamics in the northwest did not sufficiently increase. (3) The GDP, value of agricultural production, forestry, and fisheries, secondary and tertiary industries, urbanization rate, and permanent residents are important factors influencing ecosystems. The driving effects of these socioeconomic indicators and urban population development have different degrees of significance on farmland, urban, forest and wetland ecosystems during different periods of the Delta\u27s urban agglomeration

Correlated motions and relaxation behavior in polycarbonate copolymers.

We investigated effects of chemical structures on molecular motions and $\gamma$-relaxations of polycarbonates and copolymers, and established relationships between the molecular motions, the $\gamma$-relaxations and brittle ductile transition (BDT) temperatures of the materials. Bisphenol A (BPA) based polycarbonates and copolymers with well-defined chemical structures were synthesized. Fluoride and methyl groups were substituted asymmetrically onto one of the two phenylene rings within repeat units of BPA-based polycarbonates, respectively. We also synthesized polycarbonate and poly(ester carbonate) copolymers, B\sb{\rm x}T (x = 1,3,5,7,9) and B\sb{\rm x}t (x = 3,5,7,9), with mono-dispersed polycarbonate block lengths (B\sb{\rm x}) and tetramethylbisphenol A (T) and terephthalate (t) units. Dynamic mechanical and solid state NMR studies of these materials showed that the two phenylene rings within the repeat unit of the BPA do not necessarily flip in concert. Furthermore, we established a relationship between locations of the $\gamma$-relaxation peak temperatures and polymer chain mobilities, monitored by the phenylene ring $\pi$-flip motions. Creep experiments demonstrated that the copolymers aged at similar rates at aging temperatures 24\sp\circC below their corresponding T\sb{\rm g}s. For a constant aging temperature of 110\sp\circC, the copolymers having higher Tgs gave rise to lower physical aging rates. Uniaxial tensile tests of the copolymers showed that there is a relationship between the locations of the $\gamma$-relaxation peaks and the BDT temperatures. The copolymers possessing lower $\gamma$-relaxation peak temperatures exhibit lower BDT temperatures.Ph.D.Applied SciencesMaterials sciencePolymer chemistryPure SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/130611/2/9732206.pd

Effects of Environmental Regulation on Green Total Factor Productivity: An Evidence from the Yellow River Basin, China

Based on the data of 59 prefecture-level cities in the Yellow River Basin from 2011 to 2019, this paper uses the Slack Based Measure-Global Malmquist Luenberger (SBM-GML) model to measure green total factor productivity (GTFP) of the cities. Under the space–time concept of the Basin, heterogeneity analysis of the upper, middle and lower reaches of the Yellow River Basin is conducted. On this basis, a panel Tobit model is constructed to analyze the impact of environmental regulation on GTFP in the whole basin, upstream region, middle region and downstream region. The results show that the intensity of environmental regulation in the Yellow River Basin increases gradually, which is the highest in the lower reaches, followed by the middle reaches; spatially, the intensity of environmental regulation shows a certain aggregation trend. The green economic growth is realized in the whole basin, and the green technology progress effect is the driving factor of GTFP. The GTFP distribution in the upstream region is relatively concentrated, showing a slow upward trend. The distribution of GTFP in the middle reaches is discrete, and the annual difference is large. In the downstream region, it shows a trend of decline first and then increase. Environmental regulation promotes GTFP in the whole basin, upper, middle and lower reaches, accompanied by certain spatial differences. The Yellow River Basin breaks through the cost effect brought by environmental regulation and triggers technological innovation, thereby enhancing GTFP; the “Porter hypothesis” has been verified in the Yellow River Basin

B₆₃: The Most Stable Bilayer Structure with Dual Aromaticity

The emergence of a bilayer B48 cluster, which has been both theoretically predicted and experimentally observed, as well as the recent experimental synthesis of bilayer borophene sheets on Ag and Cu surfaces, has generated tremendous curiosity in the bilayer structures of boron clusters. However, the connection between bilayer boron cluster and bilayer borophene remains unknown. By combining a genetic algorithm and density functional theory calculations, a global search for the low-energy structures of the B63 cluster was conducted, revealing that the Cs bilayer structure with three interlayer B–B bonds is the most stable bilayer structure. This structure was further examined in terms of its structural stability, chemical bonding, and aromaticity. Interestingly, the interlayer bonds induce strong electronegativity and robust aromaticity. Furthermore, the dual aromaticity stems from diatropic currents originating from virtual translational transitions for both σ and π electrons. This unprecedent bilayer boron cluster is anticipated to enrich the concept of dual aromaticity and serve as a potential precursor for bilayer borophene

Development of an Adaptive Fuzzy Integral-Derivative Line-of-Sight Method for Bathymetric LiDAR Onboard Unmanned Surface Vessel

Previous control methods developed by our research team cannot satisfy the high accuracy requirements of unmanned surface vessel (USV) path-tracking during bathymetric mapping because of the excessive overshoot and slow convergence speed. For this reason, this study developed an adaptive fuzzy integral-derivative line-of-sight (AFIDLOS) method for USV path-tracking control. Integral and derivative terms were added to counteract the effect of the sideslip angle with which the USV could be quickly guided to converge to the planned path for bathymetric mapping. To obtain high accuracy of the look-ahead distance, a fuzzy control method was proposed. The proposed method was verified using simulations and outdoor experiments. The results demonstrate that the AFIDLOS method can reduce the overshoot by 79.85%, shorten the settling time by 55.32% in simulation experiments, reduce the average cross-track error by 10.91% and can ensure a 30% overlap of neighboring strips of bathymetric LiDAR outdoor mapping when compared with the traditional guidance law

Funnel plot of the result of pooled analysis.

<p>Funnel plot of the result of pooled analysis.</p