Studies on the assessment of green infrastructure (GI) practice implementation effect and cost efficiency on an urban watershed scale helps the GI practice selection and investment decisions for sponge city construction in China. However, few studies have been conducted for these topics at present. In this study, the Long-Term Hydrologic Impact Assessment—Low Impact Development (L-THIA-LID) 2.1 model was applied to assess the effectiveness and cost efficiency of GI practices on surface runoff volume reduction in an urban watershed—the Hexi watershed, Nanjing City, China. Grassed swales, bioretentions, green roofs, rain cisterns, permeable pavements, wet ponds, dry ponds, and wetlands were chosen as potential GI practices for sponge city construction based on feasibility analysis. Results showed that grassed swales were the most cost-effective practice (0.7 CNY/m³/yr), but the total implementation effect of grassed swales was not obvious due to the small area of suitable locations. Permeable pavements performed best on runoff reduction, but the cost efficiency was much lower. Correspondingly, bioretentions were compromise practices. Green roofs were the least cost-effective practices, with the cost efficiency at 122.3 CNY/m³/yr, but it was much lower for rain cisterns, which were 3.2 CNY/m³/yr. Wet ponds, dry ponds, and wetlands were potential practices implemented in development areas, of which dry ponds were the most cost-effective (2.7 CNY/m³/yr), followed by wet ponds (10.9 CNY/m³/yr). The annual runoff volume of the total area could be reduced by up to 47.01% by implementing GI practices in buildup areas. Rain cisterns (RC) and permeable pavements (PP) were the best combination for this area, and bioretentions (BR) and green roofs (GR) followed. Grassed swales (GS₁), dry ponds (DP), wet ponds (WP), and wetlands (WL) were not wise choices due to the small suitable location areas. This study also demonstrated the feasibility of the L-THIA-LID 2.1 model for the evaluation of GI practice implementation effects and cost efficiency on urban runoff in sponge city construction in China.

Assessment of the impacts of land use/cover change (LUCC) and rainfall change on surface runoff depth can help provide an understanding of the temporal trend of variation of surface runoff and assist in urban construction planning. This study evaluated the impacts of LUCC and rainfall change on surface runoff depth by adopting the well-known Soil Conservation Service-Curve Number (SCS-CN) method and the widely used Long-Term Hydrologic Impact Assessment (L-THIA) model. National hydrologic soil group map of China was generated based on a conversion from soil texture classification system. The CN values were adjusted based on the land use/cover types and soil properties in China. The L-THIA model was configured by using the adjusted CN values and then applied nationally in China. Results show that nationwide rainfall changes and LUCC from 2005 to 2010 had little impact on the distribution of surface runoff, and the high values of runoff depth were mainly located in the middle and lower reaches of the Yangtze River. Nationally, the average annual runoff depths in 2005, 2010 and 2015 were 78 mm, 83 mm and 90 mm, respectively. For the 2015 land use data, rainfall change caused the variation of surface runoff depth ranging from −203 mm to 476 mm in different regions. LUCC from 2005 to 2015 did not cause obvious change of surface runoff depth, but expansion of developed land led to runoff depth increases ranging from 0 mm to 570 mm and 0 mm to 742 mm from 2005 to 2010 and 2010 to 2015, respectively. Potential solutions to urban land use change and surface runoff control were also analyzed.

Computer-generated hologram (CGH) is an effective way to compensate wavefront in null test of aspheric surfaces and freeform surfaces. Our strategies of CGH design and fabrication for optical testing are presented, and an experiment demonstrating the compensation results of CGH and null lens is also reported. In order to design complex CGH, software was developed, with which we can design a CGH including three sections: main section for compensating wavefront in null test, alignment section for adjusting the relative position between CGH and interferometer, and fiducial section for projecting fiducial marks around the optics under test. The design result is represented in GDS II format file which could drive a laser-direct-writer-machine to fabricate a photomask. Then, a 1:1 replication process is applied to duplicate the patterns from photomask to a parallel optical substrate whose surface is error better than λ/60 rms. Finally, an off-axis aspheric surface was tested with CGH and null lens respectively. The test result with CGH (0.019λ;rms) is almost the same as the result with null lens (0.020λ rms). This experiment also demonstrated that fiducial marks projected by CGH can be used to guide the alignment of the optics and measurement of its off-axis distance.

The coupling coordination of urbanization and urban resilience is a key issue for achieving sustainable urban development. Taking 49 prefecture-level and above cities in the Beijing-Tianjin-Hebei (BTH), the Yangtze River Delta (YRD) and the Pearl River Delta (PRD)—China’s three major coastal urban agglomerations—as research objects, this paper constructs an evaluation index system for urbanization and urban resilience, and employs the CRITIC–entropy weight composite method, the coupling coordination degree model and kernel density estimation to measure the evolutionary characteristics of coupling coordination between urbanization and urban resilience in the three agglomerations during 2013–2023, and further identifies the key influencing factors using a panel fixed-effects model. The results show that (1) the coupling coordination degree of the three urban agglomerations increased continuously, with the PRD taking the lead in 2023 (0.6650), the YRD ranking second (0.6315) and the BTH ranking third (0.5627); however, their coupling coordination paths diverged markedly, specifically manifesting as a catch-up convergence pattern in the BTH, a balanced advancement pattern in the YRD and a polarization-divergence pattern in the PRD. (2) Opening-up and digital economy development are robust positive drivers of the coupling coordination level, and their positive effects are largely universal across regions; urban population agglomeration and government intervention constitute significant negative constraints, among which the inhibitory effect of government intervention exhibits genuine regional heterogeneity, being most prominent in the YRD, followed by the PRD, while failing the significance test in the BTH; technological innovation fails to pass the significance test; the full-sample effect of spatial structure is insignificant, but its influence exhibits significant regional heterogeneity, with a significantly positive association in the PRD. This study systematically reveals the regional differentiation rules governing the synergistic evolution of urbanization and resilience in the three urban agglomerations, providing empirical support for differentiated policies to promote the deep integrated development of urbanization and urban resilience.