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Autonomous groups of particles swarm optimization (AGPSO), inspired by individual diversity in biological swarms such as insects or birds, is a modified particle swarm optimization (PSO) variant. The AGPSO method is simple to understand and easy to implement on a computer. It has achieved an impressive performance on high-dimensional optimization tasks. However, AGPSO also struggles with premature convergence, low solution accuracy and easily falls into local optimum solutions. To overcome these drawbacks, random-walk autonomous group particle swarm optimization (RW-AGPSO) is proposed. In the RW-AGPSO algorithm, Levy flights and dynamically changing weight strategies are introduced to balance exploration and exploitation. The search accuracy and optimization performance of the RW-AGPSO algorithm are verified on 23 well-known benchmark test functions. The experimental results reveal that, for almost all low- and high-dimensional unimodal and multimodal functions, the RW-AGPSO technique has superior optimization performance when compared with three AGPSO variants, four PSO approaches and other recently proposed algorithms. In addition, the performance of the RW-AGPSO has also been tested on the CEC’14 test suite and three real-world engineering problems. The results show that the RW-AGPSO is effective for solving high complexity problems.

Since the early 2000s, China has carried out extensive “grain-for-green” and grazing exclusion practices to combat desertification in the desertification-prone region (DPR). However, the environmental and socioeconomic impacts of these practices remain unclear. We quantify and compare the changes in fractional vegetation cover (FVC) with economic and population data in the DPR before and after the implementation of these environmental programmes. Here we show that climatic change and CO2 fertilization are relatively strong drivers of vegetation rehabilitation from 2001-2020 in the DPR, and the declines in the direct incomes of farmers and herders caused by ecological practices exceed the subsidies provided by governments. To minimize economic hardship, enhance food security, and improve the returns on policy investments in the DPR, China needs to adapt its environmental programmes to address the potential impacts of future climate change and create positive synergies to combat desertification and improve the economy in this region.

Metamaterials are artificial materials that can achieve unusual properties through unique structures. In particular, their “invisibility” property has attracted enormous attention due to its little or negligible disturbance to the background field that avoids detection. This invisibility feature is not only useful for the optical field, but it is also important for any field manipulation that requires minimum disturbance to the background, such as the flow field manipulation inside the human body. There are several conventional invisible metamaterial designs: a cloak can isolate the influence between the internal and external fields, a concentrator can concentrate the external field to form an intensified internal field, and a rotator can rotate the internal field by a specific angle with respect to the external field. However, a multifunctional invisible device that can continuously tune across all these functions has never been realized due to its challenging requirements on material properties. Inside a porous medium flow, however, we overcome these challenges and realize such a multifunctional metamaterial. Our hydrodynamic device can manipulate both the magnitude and the direction of the internal flow and, at the same time, make negligible disturbance to the external flow. Thus, we integrate the functions of the cloak, concentrator, and rotator within one single hydrodynamic metamaterial, and such metamaterials may find potential applications in biomedical areas such as tissue engineering and drug release.

Understanding the cooling effect (CE) of urban parks is vital to mitigate the urban heat islands. ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) land surface temperature data (LST) data were used to construct diurnal thermal variations to explore the CE of urban parks in the fifth ring regions of Beijing. Local climate zone (LCZ) classification was used to distinguish different parks for examining the internal CE of parks. New subclasses of LCZ (e.g., LCZAG, LCZBG, LCZCG) were created based on the basic subclasses, such as LCZA (mainly consist of dense trees), LCZB (scattered tress with dense bush), LCZC (scattered bush), and LCZG (water). The external CE of parks was evaluated in different directions, and the impacts of buildings around parks on the external CE were also analyzed. The results showed that urban parks tended to heat up slower than the whole urban regions during the daytime, and water releasing energy dominated the mean LST of parks at night. Large parks meeting the minimum area (40,000 m2) of LCZ had better CE inside each park during the daytime. Three hundred thirty four large parks were divided into six types of LCZ. The strength of the CE decrease with the increases of distance, and seemed to exist at a distance of up to 150–200 m. Such impacts of parks were insignificant at night. In addition, parks containing certain dense trees and water had better CE inside and out. The height and density of buildings had a relatively obvious impact on the CE of parks. This study can provide insight into the impacts of urban parks on the urban thermal environment and promote the CE of urban parks in future urban planning.

For various engineering and industrial applications it is desirable to realize mechanical systems with broadly adjustable elasticity to respond flexibly to the external environment. Here we discover a topology-correlated transition between affine and non-affine regimes in elasticity in both two- and three-dimensional packing-derived networks. Based on this transition, we numerically design and experimentally realize multifunctional systems with adjustable elasticity. Within one system, we achieve solid-like affine response, liquid-like non-affine response and a continuous tunability in between. Moreover, the system also exhibits a broadly tunable Poisson's ratio from positive to negative values, which is of practical interest for energy absorption and for fracture-resistant materials. Our study reveals a fundamental connection between elasticity and network topology, and demonstrates its practical potential for designing mechanical systems and metamaterials., 10 pages, 5 figures

Land salinization is a global environmental problem, and how to manage saline soils and promote healthy ecosystems has become a major challenge. China-Singapore Tianjin Eco-City is located in coastal land reclamation areas, so salinization is severe in this region. In this study, geostatistical methods, the ordinary kriging method, and principal component analysis were used. Vertical sampling was performed over three layers (0-20 cm, 20-40 cm, and 40-60 cm) at 184 locations within the study area to produce a total of 542 soil samples. It was found that areas with soluble salt contents greater than 3000 mg/kg account for over 90% of the study area, and high soluble salt content in surface layer soils is the dominant factor in soil salinization. Na

Dimensionality often strongly affects material properties and phase transition behaviors, but its effects on crystal surfaces, such as roughening and premelting, have been poorly studied. Our simulation revealed that these surface behaviors are distinct in monolayer and multilayer Lennard-Jones (LJ) crystals. Solid surfaces fluctuate as capillary waves during the roughening process, but complete roughening is preempted by premelting. As the melting temperature is approached, the thickness of the premelted liquid layer approaches a constant (i.e., blocked premelting) for monolayer crystals, but diverges as a power law (i.e., complete premelting) for bilayer and trilayer crystals. The surface liquids of monolayer crystals contain crystalline patches and exhibits rough liquid-vapour and liquid-crystal interfaces, in contrast to the normal surface liquids of bilayer and trilayer crystals. Monolayer crystals melt heterogeneously from the surface without forming a hexatic phase and produce many vacancies.

In the process of rapid urbanization, urban heat island (UHI) effect has been showing more and more significant impacts on human well-being. Therefore, a more detailed understanding of the impact of three-dimensional (3D) building morphology on UHI effect across a continuum of spatial scales will be necessary to guide and improve the human settlement.This study selected 31 provincial capital cities of mainland China to analyze the impacts of the 3D building morphology, including the number, area, height, volume, and the surface area of the buildings, on the land surface temperature (LST). By exploring how the influence of 3D building morphology on LST changes with the increase of spatial scale (between 0 and 600 m radii), this study finally recognized which 3D building morphology index is the most significant index affecting LST in different cities, and which spatial scale these 3D building morphology indexes have the most significant impact on LST. The results showed that the building area is the most important 3D building morphology parameter affecting the LST, while the building height has the slightest influence on the LST. These effects are more significant in the spatial scale of 150 m–540 m, and the spatial scale increases with the increase of building areas in developed cities. These results highlight the necessity of considering fine-grained management in the governance and alleviating of the urban thermal environment through urban planning and urban renewal strategies.

Annual land use land cover (LULC) change information at medium spatial resolution (i.e. at 30 m) is required in numerous subjects, such as biophysical modelling, land management and global change studies. Annual LULC information, however, is usually not available at continental or national scale due to reasons such as insufficient remote sensing data coverage or lack of computational capabilities. Here we integrate high temporal resolution and coarse spatial resolution satellite images (i.e., Moderate Resolution Imaging Spectroradiometer (MODIS) and Global Inventory Modelling and Mapping Studies (GIMMS) normalized difference vegetation index (NDVI)) with high spatial resolution datasets (China’s Land-Use/cover Datasets (CLUDs) derived from 30-meter Landsat TM/ETM+/OLI) to generate reliable annual nominal 30 m LULC maps for the whole of China between 1980 and 2015. We also test the performance of a statistical based change detection algorithm (Breaks for Additive Seasonal and Trend), originally designed for tracking forest change, in classifying all-type LULC change. As a result, a nominal 30 m annual land use/land cover datasets (CLUD-A) from 1980 to 2015 was developed for the whole China. The mapping results were assessed with a change sample dataset, a regional annual validation sample set and a three-year China sample set. Of the detected change years, 75.61% matched the exact time of conversion within ±1 year. Annual mapping results provided a detail process of urbanization, deforestation, afforestation, water and cropland dynamics over the past 36 years. The consistent characterization of land change dynamics for China can be further used in scientific research and to support land management for policy-makers.

Given that glaciers are good indicators of climate change, it is of great scientific significance to study glacier change for regional environmental protection and water resource development and utilization. Using the Google Earth Engine (GEE) platform, we obtained the distribution of glaciers in western China in 2000, 2005, 2010, 2015, and 2020. Then, we analyzed the temporal and spatial evolutions of the glacier areas and their responses to climate change. The results showed that there were 52,384 glaciers in western China in 2020, with an area of 42,903.57 km2, among which those belonging to the headwater of the Tarim River are the largest, accounting for 35.25% of the total area. From 2000 to 2020, the glaciers indicated an overall trend of retreat, with the total area decreasing by 15,575.94 km2 at a change rate of 1.46%/a. From 2000 to 2010, glaciers in the southeast Qinghai-Tibet Plateau (QTP) and Qilian Mountains saw the fastest area loss (>4%/a), followed by the Tianshan Mountains (3.31%/a), while those in the Pamir-Karakoram-West Kunlun regions and the Qiangtang Plateau had the slowest loss. From 2010 to 2020, the glacier retreat rate exhibited an accelerating trend in southeast QTP and the western Himalayas, while it slowed down in the Tianshan Mountains. The change in glaciers was greatly attributed to the combination of snowfall and summer temperature trends. The glaciers in southeast QTP showed an accelerated retreat tendency, probably due to the accelerating snowfall decrease and continuous temperature rise. The decreasing temperature mitigated the loss of glacier area in the Pamir-Karakoram-West Kunlun regions with continuously decreasing snowfall.

The hydrodynamic interactions (HIs) of two colloidal spheres characterized by the translation–translation (T–T) couplings have been studied under various confinements, but little is known regarding the HIs of anisotropic particles and rotational motions, which are common in nature and industry. Here, we study the T–T, rotation–rotation (R–R) and translation–rotation (T–R) hydrodynamic couplings of two colloidal ellipsoids sediment on the bottoms of channels in experiment, theory and simulation. We find that the degree of confinement and the particle shape anisotropy are critical tuning factors resulting in anomalous hydrodynamic and diffusive behaviours. The negative R–R coupling reflects the tendency of opposite rotations of two neighbouring ellipsoids. The positive T–R coupling reflects that an ellipsoid rotates away from the channel axis as another ellipsoid approaches. As the channel width increases, the positive T–T coupling changes to an abnormal negative coupling, indicating that the single-file diffusion can exist even in wide channels. By contrast, only positive T–T couplings were observed for spheres in channels. The T–T coupling increases with the aspect ratio p. The R–R coupling is the maximum at a moderate p ~ 2.8. The T–R coupling is the maximum at a moderate degree of confinement. The spatial range of HIs is longer than that of spheres and increases with p. We propose a simple model which reproduces some coupling phenomena between two ellipsoids, and it is further confirmed by low-Reynolds-number hydrodynamic simulation. These findings shed new light on anisotropic particle diffusion in porous media, transport through membranes, microfluidics and microrheology.

Northeast China is a prominent base for commercial grain production nationwide. Soil erosion, a primary cause of land degradation and grain yield decrease, has become an imminent issue and is still not well documented in Northeast China. Thus, a comprehensive assessment of soil erosion in Northeast China is essential for deepening our understanding of various geological and agricultural issues, such as control of regional water and soil losses, anti-degeneration attempts on black soil, preservation of land fertility, and safeguarding of national food security. Based on the Revised Universal Soil Loss Equation (RUSLE) and the Revised Wind Erosion Equation (RWEQ) models, this paper comprehensively assessed the water and wind erosion in Northeast China from 2000 to 2020 and analyzed the current situation, as well as the spatial and temporal evolution of soil erosion. The results suggest the following: (1) The degree of soil erosion in Northeast China was mainly slight, and water erosion was more severe than wind erosion. Water and wind erosion in bare land and grassland were more intensive than in cropland and forests. The Liao River Plain (LRP) has undergone relatively intensive water erosion, while the wind erosion in the Greater Kinggan Mountains Region (GKMR) was more intensive than in other sub-regions. (2) A slight intensifying trend of water erosion could be observed in Northeast China from 2000 to 2020, where the area of slight water erosion decreased and that of light and intensive water erosion increased. The water erosion in the Changbai Mountain Region (CBMR), the Sanjiang Plain (SJP), and the Songnen Plain (SNP) intensified, while the LRP has undergone slower water erosion than before. The water erosion in bare land and cropland intensified, while the water erosion in grassland and forests slowed down. Compared to the first decade (2000–2010), the second decade (2010–2020) in the timespan of study had a reversed trend of water erosion from intensifying to moderating, which means water erosion was alleviated. (3) A moderating trend in wind erosion could be found in Northeast China from 2000 to 2020, where the area of slight wind erosion increased and that of light, moderate, and intensive wind erosion decreased. The wind erosion in the LRP showed a pronounced decrease, and the wind erosion in bare land and cropland also considerably decreased. Compared to the first decade, the amount of wind erosion in the second decade decreased by 18.2%, but the rate in the second decade decreased slowly or even increased. These two facts indicate that wind erosion in Northeast China has alleviated, but this trend is gradually slowing down. Soil erosion is caused by multiple factors, such as climate, topography, soil, and human activities. This study provides important implications for our understanding of soil erosion control and management in Northeast China. In sub-regions with severe erosion, such as the LRP and the GKMR, we can adopt methods such as zero tillage, cross ridge tillage, and straw mulching according to the local characteristics of soil erosion to slow down the process.

The significance of relative locations between the internal transport barrier (ITB) and the minimum value of safety factor ( qmin) is proved by the magnetohydrodynamic (MHD) stability of ITB plasma, in shaped tokamak devices. In this work, equilibria of HL-2M tokamak with different locations of ITB and qmin are generated using the TOQ code, and the kink-ballooning stabilities of the equilibria with respect to 1 ≤ n ≤ 20 ( n is the toroidal mode number) are simulated with the BOUT++ code. The results show that the MHD instability is suppressed magnificently, when the location of ITB is close to the core, while qmin is to the edge. The instability of the equilibrium is also stabilized when ITB is in the region with negative magnetic shear. As ITB moves toward the core or qmin moves toward the edge, the amplitude of negative magnetic shear increases, and the ITB gets closer to the negative magnetic shear, which benefits the MHD stability. Meanwhile, when qmin moves toward the edge, the elongation of the magnetic surface in the ITB region increases, and the area of the magnetic surface on the strong field side expands, which optimizes the magnetic surface distribution and improves the MHD stability.

Significance Active suspensions of microswimmers demonstrate novel emergent behaviors (self-organizations, active turbulence, etc.) on macroscopic length scales. For such systems with, minimally, thousands of microswimmers, direct numerical simulations of the hydrodynamic interactions are computationally infeasible, and reduced models are needed. We demonstrated that existing models are not satisfactory in describing the hydrodynamic interactions for microswimmers in close proximity with even qualitatively erroneous predictions, indicating a pressing need for an adequate model. We propose a model that is both physically effective and computationally efficient in describing such hydrodynamics. The main novelty of our model is the description of hydrodynamic interactions through a resistance tensor, as opposed to an effective steric interaction in existing models., Near-field hydrodynamic interactions in active fluids are essential to determine many important emergent behaviors observed, but have not been successfully modeled so far. In this work, we propose an effective model capturing the essence of the near-field hydrodynamic interactions through a tensorial coefficient of resistance, validated numerically by a pedagogic model system consisting of an Escherichia coli bacterium and a passive sphere. In a critical test case that studies the scattering angle of the bacterium–sphere pair dynamics, we prove that the near-field hydrodynamics can make a qualitative difference even for this simple two-body system: Calculations based on the proposed model reveal a region in parameter space where the bacterium is trapped by the passive sphere, a phenomenon that is regularly observed in experiments but cannot be explained by any existing model. In the end, we demonstrate that our model also leads to efficient simulation of active fluids with tens of thousands of bacteria, sufficiently large for investigations of many emergent behaviors.

Bio-inspired reversible adhesives have attracted great attention because of their promising applications in the electronic, biomedical, and robotic fields. Here, to achieve in situ reversible adhesion, a new concept is demonstrated by modulating the conformations of polydimethylsiloxane (PDMS) chains. The new adhesive, termed BGPP, is composed of the graphene/PDMS composite (GP) as the backing layer and PDMS as the micropillar array. The photothermal effect of graphene under UV irradiation heats up the micropillars, resulting in an increase in the chain conformations of PDMS and thus the contact points with the counterpart surface. The more contact points together with the alignment of PDMS chains during the shearing result in an adhesion much higher than that without UV irradiation. The adhesion switching thus does not rely on the changing of the contact area, and so the macroscopic deformation of structures is avoided. The results suggest a new design principle for light-controllable structured adhesive, which could be conceptualized into other rubbery materials.

Fine-scale population gridded datasets are of great significance in emergency response, resource allocation, and traffic planning. Many studies have developed fine-scale population spatialization m...

Knee osteoarthritis (KOA) is a degenerative joint disease leading to pain and disability for which no curative treatment exists. Intra-articular (IA) therapies are part of this multimodal approach and are approved by the Food and Drug Administration (FDA) and European Medicines Agency (EMA). Platelet-rich plasma (PRP), hyaluronic acid (HA), and corticosteroids (CS) have been increasingly used in recent years to treat KOA.To determine whether IA-PRP was superior to IA-HA or IA-CS administration routes in these patients.In this trial the patients were randomized to IA-HA (2 ml/week, for 3 weeks), IA-CS (1 ml) or IA-PRP (3 times, 4 ml, every 3 weeks) groups. The outcome was assessed using the Western Ontario and McMaster Universities (WOMAC) score prior to the first injection and then at 3, 6, 9 and 12 months. Pain was evaluated by a visual analogue scale (VAS) prior to treatment and after 12 months.In this study 120 patients were randomized into 3 groups. There was a significant improvement in all scores (WOMAC, VAS) in each group compared to the pretreatment values (P 0.05). The mean WOMAC scores for the IA-HA group from pretreatment to 3, 6, 9, and 12 months were 47.23 ± 5.37, 25.02 ± 4.98, 26.38 ± 5.20, 27.86 ± 4.34, and 30.64 ± 8.36, respectively. Similar improvements were noted in the IA-CS and IA-PRP groups. There were no significant differences in the WOMAC scores between the 3 groups 3 months after treatment (P 0.05) but IA-PRP showed significantly lower scores 6, 9 and 12 months after treatment (P 0.05).Intra-articular PRP injections into the knee for symptomatic early stages of KOA are a valid treatment option. The clinical efficacy of IA-PRP is comparable to that of the IA-HA and IA-CS forms after 3 months and the long-term efficacy of IA PRP is superior to IA-HA and IA-CS.

The natural habitats of microorganisms in the human microbiome, ocean and soil ecosystems are full of colloids and macromolecules. Such environments exhibit non-Newtonian flow properties, drastically affecting the locomotion of microorganisms

Background Virtual reality (VR) is an innovation that permits the individual to discover and operate within three-dimensional (3D) environment to gain practical understanding. This research aimed to examine the general efficiency of VR for teaching medical anatomy. Methods We executed a meta-analysis of randomized controlled studies of the performance of VR anatomy education. We browsed five databases from the year 1990 to 2019. Ultimately, 15 randomized controlled trials with a teaching outcome measure analysis were included. Two authors separately chose studies, extracted information, and examined the risk of bias. The primary outcomes were examination scores of the students. Secondary outcomes were the degrees of satisfaction of the students. Random-effects models were used for the pooled evaluations of scores and satisfaction degrees. Standardized mean difference (SMD) was applied to assess the systematic results. The heterogeneity was determined by I2 statistics, and then was investigated by meta-regression and subgroup analyses. Results In this review, we screened and included fifteen randomized controlled researches (816 students). The pooled analysis of primary outcomes showed that VR improves test scores moderately compared with other approaches (standardized mean difference [SMD] = 0.53; 95% Confidence Interval [CI] 0.09–0.97, p I2 = 87.8%). The high homogeneity indicated that the studies were different from each other. Therefore, we carried out meta-regression as well as subgroup analyses using seven variables (year, country, learners, course, intervention, comparator, and duration). We found that VR improves post-intervention test score of anatomy compared with other types of teaching methods. Conclusions The finding confirms that VR may act as an efficient way to improve the learners’ level of anatomy knowledge. Future research should assess other factors like degree of satisfaction, cost-effectiveness, and adverse reactions when evaluating the teaching effectiveness of VR in anatomy.

For various engineering and industrial applications it is desirable to realize mechanical systems with broadly adjustable elasticity to respond flexibly to the external environment. Here we discover a topology-correlated transition between affine and non-affine regimes in elasticity in both two- and three-dimensional packing-derived networks. Based on this transition, we numerically design and experimentally realize multifunctional systems with adjustable elasticity. Within one system, we achieve solid-like affine response, liquid-like non-affine response and a continuous tunability in between. Moreover, the system also exhibits a broadly tunable Poisson's ratio from positive to negative values, which is of practical interest for energy absorption and for fracture-resistant materials. Our study reveals a fundamental connection between elasticity and network topology, and demonstrates its practical potential for designing mechanical systems and metamaterials.

Urban parks can effectively mitigate the urban heat island (UHI) effect. Many studies have investigated the relationship between the shape, size, interior components and cooling effect of the park, little attention have been given to explore the relationship between land surface temperature (LST) of central park and buildings in the neighboring areas. This study has explored the effect of the neighboring building on LST of central park, taking Beijing as the study area. The results showed that the cold island footprint of the park in summer was larger than that in winter (with an average area of 0.15 km2 larger). The components of building in cold island footprint of the park were dominated by middle-rese building (MRB). LSI of MRB and AREA_SD of LMB were identified as the key explanatory variables in summer and winter, respectively, which could explained 16.8% and 13.9% of the variance in the park’s LST. This study could extend scientific understanding of the effect of building on park’s LST, and could provide guidance to urban planners on how to mitigate the UHI effects through the rational allocation of buildings.

Urban Heat Island (UHI), a phenomenon characterized by significantly higher air and land surface temperatures (LSTs) in urban areas than in suburban areas, results in land use change from non-urban to urban land and is accompanied by increases in anthropogenic heat release. A variety of land use contribution indexes have been proposed to quantitatively calculate the impact of land use types on UHI. However, these indexes can only show the impact of specific land use types on UHI. In fact, the area and the intensity (which also can be considered as the average temperature) of land use change jointly determine the regional UHI. The purpose of this paper is to develop an algorithm to quantitatively reveal the influence of the area and the intensity of land use change on regional UHI. MODIS LST products and 1:1,000,000 land use data sets were used to quantitatively calculate the seasonal and interannual contributions of land use change on regional UHI between 2005 and 2018 in China. These results have theoretical and practical significance for further understanding the formation mechanism of urban thermal environment and its mitigation measures.

The equilibria of the HL-2M tokamak, designed for steady-state operation with reversed magnetic shear and double transport barriers, are calculated using TOQ code, and the n = 1 linear ideal magnetohydrodynamic (MHD) stability of the equilibria is investigated using GATO code. To improve the beta ( β N ) limit, the MHD stability of the equilibria with different heights of internal transport barrier (ITB) and edge transport barrier (ETB) is simulated. The simulation results indicate that the ITB drives low m globalized modes while the ETB drives high m edge localized modes, and thus a moderate barrier height ratio is beneficial to MHD stability. By adjusting the heights of both barriers with different plasma shapes, as well as different locations and widths of ITBs, optimal equilibria with improved MHD stability are achieved, which always have a moderate barrier height ratio unless the ITB is extremely wide or very close to the edge. In ideal-wall conditions, when the ITB is wide enough or very close to the edge, β N limits could exceed six, or even reach seven in some special cases. Increasing elongation and triangularity, broadening the ITB, as well as moving the ITB to a large minor radius, can contribute to the optimization of the β N limit, especially when combined with the stabilizing effect from an ideal wall.

Currently, most regional thermal environment (RTE) studies in urban agglomerations focus on developing countries, especially China. However, there is still a lack of comparative studies on the RTEs of urban agglomerations between China and other developed countries, such as the United States. This paper used the Beijing-Tianjin-Hebei (BTH) agglomeration in China and Boswash (the highly urbanized area extending from Boston to Washington) in the United States as examples to investigate the differences in land development patterns, RTEs and their relationship between the agglomerations of China and America. The results showed that the land development patterns of BTH and Boswash were different, as evidenced by the spatial pattern of land development intensity (LDI) and impervious surface configuration. In terms of the RTE, the sub-high land surface temperature (LST) zones were aggregated in a large and compact patch in central and northern BTH. However, the sub-high zones of the cities in Boswash were relatively separate. Moreover, the land development pattern of Boswash showed a stronger relationship with the RTE than that of BTH did. Global Moran's I between the LDI and LST in Boswash was higher than that in BTH. In addition, the correlation between impervious surface configuration and LST in Boswash was stronger than that in BTH, and this correlation was more controlled by LDI in Boswash. This study also indicated that BTH should change the land development pattern to prevent the further expansion of aggregated sub-high LST zones and control the proximity of high LST zones in cities in central and southern BTH, however, Boswash should adopt some local heat management approaches (installing cool and green roofs and creating more green space) in the core areas to help reduce the very high temperatures in the already highly developed areas where the largest fraction of people live.

Rapeseed is one of the major oil crops in China and it is very sensitive to climate change. The Yangtze River Basin is the main rapeseed production area in China. Therefore, a better understanding of the impact of climate change on rapeseed production in the basin is of both scientific and practical importance to Chinese oil industry and food security. In this study, based on climate data from 5 General Circulation Models (GCMs) with 4 representative concentration pathways (RCPs) in 2011–2040 (2020s), 2041–2070 (2050s) and 2071–2100 (2080s), we assessed the changes in rapeseed production potential between the baseline climatology of 1981–2010 and the future climatology of the 2020s, 2050s, and 2080s, respectively. The key modelling tool – the AEZ model – was updated and validated based on the observation records of 10 representative sites in the basin. Our simulations revealed that: (1) the uncertainty of the impact of climate change on rapeseed production increases with time; (2) in the middle of this century (2050s), total rapeseed production would increase significantly; (3) the average production potential increase in the 2050s for the upper, middle and lower reaches of the Yangtze River Basin is 0.939, 1.639 and 0.339 million tons respectively; (4) areas showing most significant increases in production include southern Shaanxi, central and eastern Hubei, northern Hunan, central Anhui and eastern Jiangsu.

Investigating the relationship between land surface temperature (LST) and other satellite-derived land surface parameters is beneficial to exploring adaptation and mitigation strategies for urban t...

The maintenance and improvement of ecosystem services on the Tibet Plateau are critical for national ecological security in China and are core objectives of ecological conservation in this region. In this paper, ecosystem service benefits of the Tibet Ecological Conservation Project were comprehensively assessed by estimating and mapping the spatiotemporal variation patterns of critical ecosystem services on the Tibet Plateau from 2000 to 2015. Furthermore, we linked the benefit assessment to the sustainable spatial planning of future ecological conservation strategies. Comparing the 8 years before and after the project, the water retention and carbon sink services of the forest, grassland and wetland ecosystems were slightly increased after the project, and the ecosystem sand fixation service has been steadily enhanced. The increasing forage supply service of grassland significantly reduced the grassland carrying pressure and eased the conflict between grassland and livestock. However, enhanced rainfall erosivity occurred due to increased rainfall, and root-layer soils could not recover in a short period of time, both factors have led to a decline in soil conservation service. The warm and humid climate is beneficial for the restoration of ecosystems on the Tibet Plateau, and the implementation of the Tibet Ecological Conservation Project has had a positive effect on the local improvement of ecosystem services. A new spatial planning strategy for ecological conservation was introduced and aims to establish a comprehensive, nationwide system to protect important natural ecosystems and wildlife, and to promote the sustainable use of natural resources.

An understanding of the spatio-temporal structure of the urban thermal environment (UTE) is important for determining the formation mechanism of the urban heat island (UHI) effect. The empirical or...

The Tiangong-1 Hyperspectral Imager (HSI) is a relatively new spaceborne hyperspectral remote sensing system that was launched by the Chinese government on September 29th 2011. The system has 64 shortwave infrared (SWIR) spectral bands (1000–2500 nm) and imagery is at a spatial resolution of 20 m. This study represents an evaluation of Tiangong-1 data for the production of alteration mineral maps. Alteration mineral maps resulting from the analysis of Tiangong-1 HSI data and airborne SASI (Shortwave infrared Airborne Spectrographic Imager) data are compared for the Jintanzi area, Beishan, Gansu province, northwest China where gold bearing veins are documented. The results illustrate the detection of muscovite, kaolinite, chlorite, epidote, calcite and dolomite from Tiangong-1 HSI data and most anomalies seen in the airborne SASI data are captured. The Tiangong-1 data appears to be well suited for the detection of surface mineralogy in support of regional mapping and exploration. The data complements that which will be offered by the Chinese GF-5 Hyperspectral Imager and the German EnMAP system, both scheduled for launch in 2018.

The urban heat island (UHI) effect has many adverse impacts on natural and social environments. A better understanding of how complex urban biophysical and social structures affect UHI is crucial to improve urban thermal environments. However, few studies have investigated the effects of 2D/3D urban morphology on land surface temperature (LST) and vertical air temperature simultaneously. Using LST data retrieved from Landsat 8 images and vertical temperatures at different heights collected from unmanned aerial vehicle (UAV) measurements, this study investigated the effects of 2D and 3D urban morphology on the 3D urban thermal environment among different urban function zones (UFZs) in the snow-climate city of Changchun, China. Our main findings are: (1) the average difference in vertical temperature between heights of 1.5 and 100 m was 1.78 °C and the temperature decreasing rate was 0.027 °C/m when the height was lower than 30 m, compared to 0.014 °C/m for 30–100 m. (2) Although 3D metrics had significant impact on LST, the relationships between the 2D metrics and LST were much stronger, accounting for 61% of the variations in LST. Additionally, the 2D composition metrics had stronger correlations with LST than the configuration metrics. The influence of 3D building metrics on LST was context-dependent for different UFZs. Increasing building height could reduce LST in residential UFZs but increase LST in industrial UFZs. (3) The effect of 2D urban morphology on the vertical temperature was stronger than that on the 3D ones when the height was lower than 30 m; however, opposite results were obtained when the height was greater than 30 m. The effects of 2D or 3D metrics on vertical temperature vary depending on whether the height is larger or smaller than a threshold, which is related to the characteristics of the building height. In general, 30 m appeared to be the threshold in our study. (4) The performances of models that used both 2D and 3D metrics to explain both LST and 3D thermal environments were better than those of models that used either 2D or 3D metrics alone, especially in UFZs such as residential areas.

China has experienced extreme urban heat island effects and air pollution associated with rapid urbanization. Optimizing urban ventilation environment could relieve these environmental problems. In this study, an Urban Ventilation Network Model (UVNM) was developed to explore the impact of urban morphology and building height on the urban ventilation condition. The study calculated the ventilation resistance coefficient of building height according to fluid mechanics, and then determined the least cost path among the air inlets and outlets considering the direction and frequency of wind. Eventually, corridors at several different levels of ventilation were extracted by classifying the line densities of least cost paths, which were effectively verified through land surface temperature retrieved from the Landsat Thematic Mapper. The new model is more scientific and convenient than traditional urban construction environmental assessment software in terms of data acquisition and hardware support. The results suggest that urban design based on urban morphology and building height and considering the direction and frequency of wind would be effective for optimizing ventilation to regulate urban environmental problems.

The Southern Tianshan area is one of the most important gold belts identified by many world-class, super large and large gold deposits such as Muruntau (Uzbekistan), Kumtor (Kyrgyzstan), and Jilau (Tajikistan). Some medium- to small-scale gold deposits, such as Sawayaerdun and Bulong, have been discovered and reported in recent years at the China part of the belt. The study area, named the Wushitala area, is located in the eastern part of Southern Tianshan, and it has a strong potential for gold and other metallic mineral deposits. This study utilizes various image processing techniques, including false colour composite, band ratios, and matched filtering, to process Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data and map the distribution of hydrothermal minerals (e.g., muscovite, kaolinite, chlorite, epidote, goethite, and malachite) related to the known deposits in the Wushitala area. The identified alteration zones are coincident with the known gold and copper deposits and field samples from the study area. The distribution of the alteration zones also indicates that the acid intrusions and regional structures play an important role in focusing the mineralizing fluids. The results show that ASTER data accompanied with image processing methods and reference spectra (e.g., JPL, lab, or field measured) could be an effective technique for mapping hydrothermal alteration zones in areas with no dominant vegetation cover. Due to the extensively distributed acid intrusions and structures along the Southern Tianshan Belt, the mineral prospecting methodology is suggested for application in similar geological settings in the belt.

The impact of changes in cultivated land on the production potential of food crops in China during the period of 1990–2010 was studied using land use data and the Global Agro-ecological Zones (GAEZ) model. The contribution of crop production potential per unit cultivated land area (PPCLA) to the total food-energy based production potential (TPP) of food crops was further investigated. From 1990 to 2010, China has experienced a net increase of cultivated land, resulting from a net increase in northern China and a smaller net decrease in the south. However, the TPP reduced by 9.64 × 1012 kcal despite an overall cultivated land increase for crops. This was attributed to the spatial heterogeneity of PPCLA in the cultivated land, whereby the average PPCLA of the newly cultivated land was much lower than that of the lost land. The PPCLA gap between the newly developed land and the lost cultivated land expanded from 3.16 × 106 kcal/ha in the first decade (1990–2000) to 6.49 × 106 kcal/ha in 2000–2010. Contributions of PPCLA to TPP varied among regions, and the regions with the largest contributions were consistent with those with the largest PPCLA gaps. Such regions included the Sichuan Basin and surrounding region in 1990–2000, and the Huang-Huai-Hai Plain during 2000–2010. Based on these research findings, key implications for land use policies in relation to major food crops in China are discussed.

Monitoring urban expansion dynamically using remote sensing technology is an essential method for obtaining and understanding urban spatial structure. However, the quality of traditional optical images in some areas is poor due to clouds and fog. Compared to optical images, synthetic aperture radar (SAR) can achieve earth observations without the limits of sunlight and weather conditions, but its speckle is too obvious. This paper combined the advantages of pixel-level optical image and SAR image time series and proposed a spatiotemporal fuzzy clustering (STFC) strategy for urban expansion monitoring. This strategy includes three parts: 1) the construction of optical-SAR image mixed time series; 2) a time-series fuzzy information granulation method to ascertain change nodes; and 3) STFC to determine the change types and range. In our study, 13 TM images and 25 SAR scenes taken from 2005 to 2011 were selected as raw data. We used the proposed method to monitor the urban expansion of Chengdu, China, and then, analyzed its main causes according to the monitoring results. The results suggested that: 1) the proposed methods could effectively extract the change nodes and change pixels, with the correctness of 85.20% and the completeness of 86.06%, outperforming the time series only (nonspatial) fuzzy clustering method, as well as traditional classification methods; and 2) the urban expansion of Chengdu is most apparent from 2005 to 2011, with the expansion direction shifting from the traditional ring structure expansion to point-axis expansion following the priority given to construction of new urban areas.

The Southern Tianshan area, situated in central Asia, is one of the most important gold belts identified by many world-class, superlarge and large gold deposits. The Wushitala area, located in the eastern part of Southern Tianshan, Xinjiang (China), has a strong potential for gold and other metallic mineral deposits. However, no metallic mineral deposit or occurrence has been reported in detail for the Wushitala area in the past, apparently due to poor exploration. This study attempts to map alteration zones and acquire ore prospecting targets in the Wushitala area by integrating Landsat TM and Hyperion data with the ASTER spectral library mineral spectra. The Crosta technique and the anomaly-overlaying selection method were combined to process four temporal Landsat TM data (acquired in the same season in different years) so as to eliminate the random interference-caused false anomalies of alteration minerals (iron oxides and hydroxyl-bearing minerals and carbonates) while retaining the real anomalies. The matched filtering method was applied on Hyperion data for the detailed identification of hydrothermally altered minerals surrounding the granites in the north. The results of Hyperion data are spatially consistent with those of Landsat TM data. Furthermore, the results of Hyperion data show that the alteration minerals associated with the potash feldspar granite are dominated by muscovite and goethite. In our field campaign, fourteen sites (eleven acid intrusion-related and three structure-associated) distributed throughout the study area were inspected, all of which proved to be of geological genesis. Our study led to the discovery of three mineralization sites associated with acid intrusions and structures that were not previously documented. Due to the extensively distributed acid intrusions and structures along the southern Tianshan Belt, several other gold-iron-copper mineralized locations could be found with more detailed investigations. Our mineral prospecting methodology proved effective in the study area and is hereby suggested for application in similar geological settings.

In the context of the popular development of the low-carbon economy, the “high energy consumption, high pollution, and high emissions” of the manufacturing industry have resulted in unprecedented difficulties in the development of this industry. To achieve nationally determined contribution targets, China has formulated a series of low carbon development plans for heavy industry to reduce carbon emissions. Among these, low-carbon technological innovation has been used a new means for manufacturing enterprises to achieve sustainable development, which is highly valued by management practice. Taking Chinese manufacturing companies as an example, the present study investigates the mediating effect of green core competence on the relationship between low-carbon technological innovation and enterprise performance and evaluates the moderating impact of firm size on this relationship. In this study, 438 valid data points were empirically analyzed, and the results indicate that low-carbon technological innovation significantly and positively affects enterprise performance of manufacturing. Green core competence plays a mediating role in the positive effect of low-carbon technological innovation on enterprise performance. Firm size has a positive moderating effect on the relationship between low-carbon technological innovation and enterprise performance. Meanwhile, firm size also moderates the relationship between low-carbon technological innovation and green core competence. Namely, a larger firm size correlates with a more positive effect on the cultivation of green core capabilities from the low-carbon technological innovation of manufacturing companies and in stronger enterprise performance. Finally, this work provides constructive guidance for Chinese manufacturing companies on how to practice low-carbon production and achieve sustainable development.

In order to improve the encapsulation efficiency and shell properties of PMMA capsules, poly(MMA-co-TMPTA)/fragrance microcapsules were fabricated by in-situ polymerization with Trimethylolpropane Triacrylate (TMPTA) as the co-monomer. The poly (MMA-co-TMPTA)/fragrance microcapsules were characterized by scanning electron microscopy (SEM), thermogravimetric analyzer (TGA), pyrolysis gas chromatography-mass spectrometer (PGC-MS) and electronic nose (PEN-3). The results indicate that the poly(MMA-co-TMPTA)/fragrance microcapsules present pomegranate shape with rough and sunk surface and have the particle size in the range of 10−20 μm. poly(MMA-co-TMPTA)/fragrance microcapsules has good thermal stability, high encapsulation efficiency of 91.6 % and good slow-release property, and the fragrance on the fabric can be retained for more than 3 months.

The first-stage of an ecological conservation and restoration project in the Three-River Source Region (TRSR), China, has been in progress for eight years. However, because the ecological effects of this project remain unknown, decision making for future project implementation is hindered. Thus, in this study, we developed an index system to evaluate the effects of the ecological restoration project, by integrating field observations, remote sensing, and process-based models. Effects were assessed using trend analyses of ecosystem structures and services. Results showed positive trends in the TRSR since the beginning of the project, but not yet a return to the optima of the 1970s. Specifically, while continued degradation in grassland has been initially contained, results are still far from the desired objective, ‘grassland coverage increasing by an average of 20%–40%’. In contrast, wetlands and water bodies have generally been restored, while the water conservation and water supply capacity of watersheds have increased. Indeed, the volume of water conservation achieved in the project meets the objective of a 1.32 billion m3 increase. The effects of ecological restoration inside project regions was more significant than outside, and, in addition to climate change projects, we concluded that the implementation of ecological conservation and restoration projects has substantially contributed to vegetation restoration. Nevertheless, the degradation of grasslands has not been fundamentally reversed, and to date the project has not prevented increasing soil erosion. In sum, the effects and challenges of this first-stage project highlight the necessity of continuous and long-term ecosystem conservation efforts in this region.

The combination model of cellular automata and multi-agent system were used in this paper for simulating spatio-temporal dynamics of urban expansion and its encroachment on other lands at the regional scale. The human system(contain authorities and residents) and their behavior, the landscape system and its behavior as well as the inter actions between them were all simulated in this paper. The behavior of human system is established based on multi-agent system, the authority agent and the resident agent were both regarded as abstract entities. The cellular automata is embedded into the model for simulating the spontaneous urban growth. The impact of neighbor cells were considered so that the expansion of urban lands can be limited near the existed urban lands. Moreover, the rural residential lands have higher probability to convert to urban lands if they were close to the cities or towns. Simulation of urban expansion is undertaken on the time series from 2000 to 2020 for Tianjin metropolitan region, the largest open coastal city in northern China. The results show that Tianjin’s urban lands focus on the epitaxial expansion around the central city accompanied with the growing exurb expansion distributing in multiple districts and counties. The croplands are taken the most area of the land-use types, 1764.03 km2 are converted to urban lands, and more than one fourth of the rural residential lands are changed to urban lands in 2000–2020. The urban development and the cropland protection should be both taken into account to minimize the threats on food security and ecological environment.

Land cover is recognized as one of the fundamental terrestrial datasets required in land system change and other ecosystem related researches across the globe. The regional differentiation and spatial-temporal variation of land cover has significant impact on regional natural environment and socio-economic sustainable development. Under this context, we reconstructed the history land cover data in Siberia to provide a comparable datasets to the land cover datasets in China and abroad. In this paper, the European Space Agency (ESA) Global Land Cover Map (GlobCover), Landsat Thematic Mapper (TM), Enhanced Thematic Mapper (ETM), Multispectral Scanner (MSS) images, Google Earth images and other additional data were used to produce the land cover datasets in 1975 and 2010 in Siberia. Data evaluation show that the total user′s accuracy of land cover data in 2010 was 86.96%, which was higher than ESA GlobCover data in Siberia. The analysis on the land cover changes found that there were no big land cover changes in Siberia from 1975 to 2010 with only a few conversions between different natural forest types. The mainly changes are the conversion from deciduous needleleaf forest to deciduous broadleaf forest, deciduous needleleaf forest to mixed forest, savannas to deciduous needleleaf forest etc., indicating that the dominant driving factor of land cover changes in Siberia was natural element rather than human activities at some extent, which was very different from China. However, our purpose was not just to produce the land cover datasets at two time period or explore the driving factors of land cover changes in Siberia, we also paid attention on the significance and application of the datasets in various fields such as global climate change, geopolitics, cross-border cooperation and so on.