15 research outputs found
Land Space Ecological Restoration Zoning in Guangdong-Hong Kong-Macao Bay Area from the Perspective of Supply and Demand of Ecosystem Services
Territorial spatial ecological restoration zoning is an important basis for implementing differentiated protection and restoration strategies and an important premise for promoting the integrated protection and restoration of mountains, rivers, forests, fields, lakes, and grasses and regional coordinated governance. In the current research on territorial spatial ecological restoration zoning, less attention is paid to human demand for ecosystem services and territorial spatial ecological restoration zoning from the perspective of the supply and demand of ecosystem services. As a result, zoning is unable to solve the contradiction between human and land relations, which has a certain impact on the implementation of subsequent restoration projects. Therefore, from the perspective of ecosystem service supply and demand, this study considers the Guangdong-Hong Kong-Macao Greater Bay Area as the research area, scientifically delimiting the territorial space ecological restoration zones of the Guangdong-Hong Kong-Macao Greater Bay Area and proposes differentiated protection and restoration strategies for each zone. The results show that the spatial distribution of the comprehensive supply and demand of ecosystem services in the Guangdong-Hong Kong-Macao Greater Bay Area has a strong spatial heterogeneity. The comprehensive supply capacity mainly presented a spatial distribution pattern of high in four weeks and low in the middle, and the comprehensive demand presented a spatial distribution pattern of high in the middle and gradually decreasing from the ring to the periphery. There are many towns/streets with a spatial mismatch of supply and demand of ecosystem services (low supply and high demand; high supply and low demand), accounting for approximately 85% of the total area. There are relatively few towns/streets with spatial matching (high supply and high demand; low supply and low demand), accounting for approximately 15% of the total area. However, in space, there is a trend that the internal low-supply and high-demand areas gradually transition to the external high-supply and low-demand areas in a semicircle. According to the matching of supply and demand of ecosystem services, the Guangdong-Hong Kong-Macao Greater Bay Area was divided into four zones, and a differentiated protection and restoration strategy was proposed for each zone. In general, the key ecological conservation areas (61%) focus on nature conservation and pay attention to the maintenance of regional ecological integrity and biodiversity; the comprehensive ecological improvement zone (13%) is mainly composed of auxiliary restoration and ecological reconstruction, focusing on strengthening the construction and restoration of the suburban ecological buffer zone; the key ecological restoration areas (24%) mainly focus on auxiliary restoration and ecological remodeling to improve the ecological resilience of the area, while ecological prevention and control areas (2%) focus on nature conservation, maintaining the current ecological situation and ecological supply capacity, and preventing ecological environment degradation
Identifying and Mapping the Responses of Ecosystem Services to Land Use Change in Rapidly Urbanizing Regions: A Case Study in Foshan City, China
Rapid urbanization has degraded some important ecosystem services and threatens socioeconomic sustainability. Although many studies have focused on the effect of urbanization on ecosystem services, the effect and its threshold have not been well-identified spatially. In this study, we propose a research framework by integrating nighttime light data, the InVEST (Integrated Valuation of Environmental Service and Tradeoffs) model, and a spatial response index to characterize the response of ecosystem services to rapid urbanization. We considered Foshan City as a case study to explore the effect of rapid urbanization on ecosystem services during 2000–2018. Our results showed that rapid urbanization resulted in a 49.13% reduction in agricultural production and a 10.13% reduction in habitat quality. The spatial response index of agricultural production, habitat quality, soil retention, water yield, and carbon sequestration were 14.25%, 2.94%, 0.04%, 0.78%, and 0.07%, respectively. We found that developing urban areas had the highest spatial response index, indicating that this area was the crucial area for future land management. We consider that our research framework can help identify the key areas affected by rapid urbanization. Visualizing the spatial response index and extracting the threshold for different levels of urbanization will be conducive to sustainable urban management and planning
Donor/Acceptor Molecular Orientation-Dependent Photovoltaic Performance in All-Polymer Solar Cells
Phase Diagram of Conjugated Polymer Blend P3HT/PF12TBT and the Morphology-Dependent Photovoltaic Performance
In
this study, we systematically investigated the morphological
evolution of polyÂ(3-hexylthiophene) (P3HT) and polyÂ{2,7-(9,9-didodecyl-fluorene)-<i>alt</i>-5,5-[4′,7′-bisÂ(2-thienyl)-2′,1′,3′-benzothiadiazole]}
(PF12TBT) blend thin films cast from <i>o</i>-dichlorobenzene
(oDCB) solution and its effect on photovoltaic performance. Blend
ratio and film drying time both played a crucial role in determining
polymer blend film morphologies, including phase-separated structure
and domain size. An apparent morphological transformation from uniform
morphology to droplet and bicontinuous structure could be observed
with the P3HT/PF12TBT blend ratio ranging from 10/90 to 90/10. Uniform
morphology resulted from one component becoming dominated, and thus
no obvious phase separation could be observed. The formation of bicontinuous
morphology via a spinodal decomposition mechanism which emerged at
nearly equal blend ratio could be attributed to the similar and favorable
solubility for both polymers in processing solvent, while the asymmetric
composition led to the formation of droplet morphology via a spinodal
decomposition mechanism. In addition, the increased domain size which
resulted from coarsening of adjacent domains could be observed with
the extending film drying time. Further expanding drying time, the
thin films exhibited unsharp morphology with large domains which could
be attributed to the mixing of polymer blend with the formation of
vast P3HT crystallites and the aggregation of both donor and acceptor
via molecular diffusion. On the basis of the varying morphologies,
an approximate phase diagram of P3HT/PF12TBT blend was depicted. In
order to demonstrate the effect of various morphologies on photovoltaic
performance, devices based on films with three kinds of blend ratios
(40/60, 50/50, and 60/40) while undergoing different drying time (20,
30, and 45 s) were prepared. As the drying time extended, a gradual
decreased power conversion efficiency (PCE) could be observed for
all blend ratio devices, which resulted from the dramatic morphological
transformation from small domains to intermediate domains and then
upsharp morphology with large domains ultimately
Donor/Acceptor Molecular Orientation-Dependent Photovoltaic Performance in All-Polymer Solar Cells
The
correlated donor/acceptor (D/A) molecular orientation plays a crucial
role in solution-processed all-polymer solar cells in term of photovoltaic
performance. For the conjugated polymers PTB7-th and PÂ(NDI2OD-T2),
the preferential molecular orientation of neat PTB7-th films kept
face-on regardless of the properties of processing solvents. However,
an increasing content of face-on molecular orientation in the neat
PÂ(NDI2OD-T2) films could be found by changing processing solvents
from chloronaphthalene (CN) and <i>o</i>-dichlorobenzene
(oDCB) to chlorobenzene (CB). Besides, the neat PÂ(NDI2OD-T2) films
also exhibited a transformation of preferential molecular orientation
from face-on to edge-on when extending film drying time by casting
in the same solution. Consequently, a distribution diagram of molecular
orientation for PÂ(NDI2OD-T2) films was depicted and the same trend
could be observed for the PTB7-th/PÂ(NDI2OD-T2) blend films. By manufacture
of photovoltaic devices with blend films, the relationship between
the correlated D/A molecular orientation and device performance was
established. The short-circuit current (<i>J</i><sub>sc</sub>) of devices processed by CN, oDCB, and CB enhanced gradually from
1.24 to 8.86 mA/cm<sup>2</sup> with the correlated D/A molecular orientation
changing from face-on/edge-on to face-on/face-on, which could be attributed
to facile exciton dissociation at D/A interface with the same molecular
orientation. Therefore, the power conversion efficiency (PCE) of devices
processed by CN, oDCB, and CB improved from 0.53% to 3.52% ultimately
Development of Large-Scale Size-Controlled Adult Pancreatic Progenitor Cell Clusters by an Inkjet-Printing Technique
The generation of transplantable
β-cells from pancreatic progenitor cells (PPCs) could serve
as an ideal cell-based therapy for diabetes. Because the transplant
efficiency depends on the size of islet-like clusters, it becomes
one of the key research topics to produce PPCs with controlled cluster
sizes in a scalable manner. In this study, we used inkjet printing
to pattern biogenic nanoparticles, i.e., mutant tobacco mosaic virus
(TMV), with different spot sizes to support the formation of multicellular
clusters by PPCs. We successfully achieved TMV particle patterns with
variable features and sizes by adjusting the surface wettability and
printing speed. The spot sizes of cell-adhesive TMV mutant arrays
were in the range of 50–150 μm diameter. Mouse PPCs were
seeded on the TMV-RGD (arginine–glycine–aspartate)-patterned
polystyrene (PS) substrate, which consists of areas that either favor
(TMV-RGD) or prohibit (bare PS) cell adhesion. The PPCs stably attached,
proliferated on top of the TMV-RGD support, thus resulting in the
formation of uniform and confluent PPC clusters. Furthermore, the
aggregated PPCs also maintained their multipotency and were positive
for E-cadherin, indicating that the formation of cell–cell
junctions is critical for enhanced cell–cell contact
Malaria in China 2011-2015: an observational study
Objective To ascertain the trends and burden of malaria in China and the costs of intervention for 2011-2015 while experiencing transitions between funders during a national plan launched to interrupt malaria transmission in most counties by 2015 and ultimately eliminate malaria by 2020.Methods We analysed the spatiotemporal and demographic features of autochthonous and imported malaria using disaggregated surveillance data on malaria from 2011 to 2015, covering the range of dominant malaria vectors in China. The total and mean costs for malaria elimination were calculated by funding sources, interventions, and population at risk.Findings A total of 17,745 malaria cases, including 123 deaths (0.7%), were reported in mainland China from 2011-2015, with 89% being imported cases, mainly from Africa and Southeast Asia. Most counties (99.9%) have achieved their elimination goals by 2015, and autochthonous cases dropped from 1,469 cases in 2011 to 43 cases in 2015, mainly occurring in the regions bordering Myanmar where Anopheles minimus and An. dirus are the dominant vector species. A total of US57.2 million (42.5%) from the Global Fund and US0.05 (SD 0.03) with the highest ($0.09) in 2012 and subsequent reductions between 2013 and 2015 after the Global Fund ceased providing investments.Conclusion The autochthonous malaria burden in China has decreased significantly, and malaria elimination is an achievable prospect in China. The key challenge is to address the remaining autochthonous transmission, as well as simultaneously reducing importation from Africa and Southeast Asia. Continued efforts and appropriate levels of investment are needed in the 2016-2020 period to achieve elimination. Keywords: Malaria; epidemiology; elimination; cost; importation; China.<br/