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The assessment of regional economic security (RES) is mainly based on the theoretical ideas of political economy and marginalism, and the research areas are mainly concentrated in European and American countries/regions, especially Eastern Europe. Taking the Qinghai–Tibet Plateau in China as an example, this paper constructs a triple-dimensional analytical framework, resources, and environmental–economic foundation-driving forces, based on the institutional approach of economic geography, with the purpose of making up for the deficiency of the extant literature, which pays little attention to regional characteristics and the dynamic mechanism concerning RES, and to provide a tool to identify key factors affecting RES. This paper obtained the main conclusions as follows. (1) The index of the economic security in the Qinghai–Tibet Plateau is on the rise, and the difference at the level of RES among cities is significant but tends to decrease. (2) There is a significant spatial autocorrelation among cities in the Qinghai–Tibet Plateau in terms of RES. The high-value areas are concentrated along the southeast edge, and the low-value areas are concentrated in the central areas of the west. (3) Despite lower weight values, the weakness of the economic foundation and the fragility of the ecological environment has increasingly hampered the improvement of the economic security in the Qinghai–Tibet Plateau. In terms of driving forces, it is the support of the central government and aid programs of other provinces that contributes to its economic development.

As an important cause of global warming, CO2 emissions have become a research hotspot in recent years. Industrial transfer impacts regional CO2 emissions and is related to the low-carbon development of regional industries. Taking the Beijing-Tianjin-Hebei region (BTH region) as an example, this study analysed industrial transfer’s direct and indirect impacts on CO2 emissions based on a mediating model and two-way fixed effect panel regression. The results obtained indicate that industrial transfer-in has promoted CO2 emissions to a small extent, and the positive impact of industrial transfer-in on CO2 emissions wanes over time. Industrial transfer affects CO2 emissions by acting on the economic level, on population size, and on urbanisation level, but the indirect effect is weaker than the direct effect. Industrial transfer does not lead to technological upgrading, but the latter is an effective means of carbon emission reduction. Industrial transfer-in has shown a positive effect on CO2 emissions for most cities, but there are exceptions, such as Cangzhou. In the future, the BTH region should maintain coordinated development among cities and improve the cooperative innovation mechanism for energy conservation and emission reduction.

This study seeks to investigate how rural migrants from less developed areas survive the hurdles of starting businesses in the host region in China from the perspective of mixed embeddedness. Based...

Aiming at the problem of insufficient feature utilization, small convolution layer width and single convolution scale in traditional residual network in flower image classification, a flower image classification algorithm based on multi-scale dense residual network proposes. The first layer of the algorithm uses a convolution group composed of multi-scale convolutions, and then replaces the single-path convolution in the residual block with a multi-path parallel convolution group composed of different numbers of convolutions, and finally add dense connections between the difference block to strengthen the feature flow of different residual blocks of the network and enhance the feature utilization of the network. The experimental results show that the accuracy of this algorithm in flower classification is 87.91%, it is higher than the traditional residual network.

The use of cement emulsified asphalt mortar (CA mortar) in the track structure of high-speed speed railways has been gaining considerations by many researchers due to its coupled merits of the strength of cement as well as the flexibility of asphalt material. The asphalt to cement ratio (A/C) and the compatibility among constituent materials are crucial to the properties of CA mortar. To improve the performance properties and application of CA mortar, it is imperative to have a broad understanding of the composition mechanisms and compatibility between constituent materials. This paper summarizes interesting research outcomes related to the composition and properties of CA mortar. The consumption of water by cement promotes the breakdown of emulsified asphalt, likewise, the adsorption of asphalt droplets on the surface of cement grains retards the hydration process of cement. An appropriate A/C is required for the cement hydration rate to match the speed of demulsification of asphalt emulsion. Depending on the type and properties for which the CA mortar is designed to possess, the A/C ranges from 0.2 to 0.6 for type 1 (CAM I), and 0.6 to 1.2 for type 2 (CAM II). This paper also discusses measures taken to improve performance properties, compatibility, the interaction between constituent materials of CA mortar, and the use of additives as a partial replacement of cement in CA mortar production. The current review also suggests areas of interest for future research studies. This paper is useful to those who aim to understand or study the composition mechanisms and performance properties of CA mortar.

Skill upgrading, the increase in the percentage of skilled workers in the employment population, boosts the economic growth of developing countries and sustains their industrial competitiveness. The international economics literature discusses the effects of international trade on skill upgrading, ignoring the potential role of agglomeration externalities. This paper takes China as a case study, which has been encountering a serious challenge about how to strengthen its industrial competitiveness in the world through skill upgrading as its population dividend decreases. The panel data of 2005, 2010 and 2015 from prefecture-level cities in China were used for regression analysis to explore the benefits from agglomeration externalities, including specialization and diversification effects, on skill upgrading. The results show that both the specialization effect and diversification effect do promote skill upgrading. Furthermore, there are significant differences in the influence of local agglomeration externalities across different regions, and the positive effect brought about by specialization externalities is usually dominant in undeveloped, inland or small cities, compared with the diversification in developed or coastal cities. Besides, manufacturing agglomerations exhibit positive externalities to skill upgrading mainly through specialization, while the service agglomerations mainly promote skill upgrading by means of diversification.

In the realistic video monitoring environment, the traditional super-resolution reconstruction technique based on prior knowledge is not suitable for monitoring the super-resolution reconstruction of the image. In this paper, a super-resolution reconstruction algorithm of target image based on learning background is proposed. The first part of the algorithm is to design a non-manifolds consistency algorithm for super-resolution reconstruction of the whole video surveillance image. The second part of the algorithm, from video surveillance images in the background, to select the characteristics significantly, and the relatively fixed background. And then to study the background, study a mapping function can improve image quality. Finally, the mapping function to restoration image of interested target, so that we can better recover the structure and texture of target image details. The experimental results show that the proposed algorithm improves both the objective evaluation index and the subjective visual effect.

Vegetation coverage is a key variable in terrestrial ecosystem monitoring and climate change research and is closely related to soil erosion and land desertification. In this article, we aimed to resolve two key scientific issues: (1) quantifying the spatial-temporal vegetation dynamics in the Otindag Sandy Land (OSL), and (2) identifying the relative importance of climate factors and human activities in impacting vegetation dynamics. Based on correlation analysis, simple regression analysis, and the partial derivative formula method, we examined the spatiotemporal variation of vegetation coverage in the OSL, belonging to the arid and semiarid region of northern China, and their interaction with climate-human factors. The results showed that the vegetation coverage of the area showed a downward trend with a rate of &minus, 0.0006/a during 2001&ndash, 2017, and gradually decreased from east to west. Precipitation was the main climate factor controlling the overall distribution pattern of vegetation coverage, while the human factors had a more severe impact on the vegetation coverage than the climate factors in such a short period, and the overall impact was negative. Among the human factors, population pressure, urbanization, industrialization, pastoral production activities, and residents&rsquo, lifestyles had a negative impact. However, ecological restoration polices alleviated the contradiction between human development and vegetation deterioration. The results of this article provide a scientific basis for restoring grassland systems in arid and semi-arid areas

In order to solve the problems of the sudden loss of fluidity and low expansion rate of CAM I (cement asphalt mortar type I) in a construction site with high environmental temperature, this paper studies the effect of temperature on the fluidity, expansion ratio and pH value of CAM I. The mechanism of action was analyzed by IR (infrared spectrometry), SEM (scanning electron microscopy) and other test methods. The results showed that a high temperature accelerates aluminate formation in cement paste. Aluminate adsorbs emulsifiers leading to demulsification of emulsified asphalt, and wrapped on the surface of cement particles, this causes CAM I to lose its fluidity rapidly. The aluminum powder gasification reaction is inhibited, resulting in an abnormal change in the expansion ratio. Based on findings, the application of an appropriate amount of superplasticizers can effectively improve the workability and expansion characteristics of CAM I at a high temperature.

In order to improve the stability of air bubbles in fresh concrete, it is of great significance to have a better understanding of the mechanisms and main influencing factors of bubble stability. In the present review, the formation and collapse process of air bubbles in fresh concrete are essentially detailed; and the advances of major influencing factors of bubble stability are summarized. The results show that the surface tension of air–liquid interface exerts a huge impact on bubble stability by reducing surface free energy and Plateau drainage, as well as increasing the Gibbs surface elasticity. However, surface tension may not be the only determinant of bubble stability. Both the strength of bubble film and the diffusion rate of air through the membrane may also dominate bubble stability. The application of nano-silica is a current trend and plays a key role in ameliorating bubble stability. The foam stability could be increased by 6 times when the mass fraction of nano-particle reached 1.5%.

The paper addresses the structure-agency dilemma of interactive learning in innovation systems, namely the structuration process of how macro-conditions shape micro-actions of firms and the agency ...

The extant literature has debated the impact of urbanization on CO2 emissions with a focus on population urbanization but has paid little attention to the other dimensions of urbanization, including economy urbanization and land urbanization, which may have different effects on CO2 emissions. Based on panel data for 351 cities in China from 2000-2015, this paper uses the spatial Durbin model and threshold regression model to explore the impact of urbanization on CO2 emissions. The results show that a nonlinear relationship exists between the multiple dimensions of urbanization and CO2 emissions. Firstly, all three dimensions of urbanization are affected by a spatial dependence on CO2 emissions. Secondly, the impact of urbanization on CO2 emissions exhibits significant heterogeneity in terms of urban population sizes. The economy urbanization of small cities, medium-sized cities and large cities plays a significant role in promoting CO2 emissions, but has the opposite effect on megacities. Population urbanization promotes CO2 emissions in small cities and megacities. Land urbanization has a negative impact on small cities and megacities and has a positive impact on large and medium-sized cities. Thirdly, urbanisation exhibits a threshold effect on CO2 emissions due to different levels of environmental technology.

This study has investigated the characteristics of air-voids structure and compressive strength of air-entrained concrete at normal atmospheric pressure (P = 1 atm) area and low atmospheric pressure (0.7 P = 0.7 atm) area. The hardened air-voids structure analyzer and the scanning electron microscope (SEM) were employed to evaluate the structure and the micromorphology of air-voids. Results showed that when specimens were formed and tested at 0.7 P, the fresh and hardened air content were separately 13.8%–41.3% and 20%–53% lower; the spacing factor and the average air-voids diameter were 11.6%–37.4% and 14.6%–30.3% larger respectively; the proportion of air-voids within 400–2500 μm was 7%–21% higher; the air-voids shell was much thinner; and the compressive strength of concrete at 3 days, 7 days and 28 days under 0.7 P were respectively 19%–21%, 5%–24% and 14%–19% lower than that at P. It confirmed that when at 0.7 P, the nucleation and the development of air bubbles were harder, the air-voids structure was abnormal, thus the compressive strength of concrete was deteriorated.

A dynamic water surface image is divided into image blocks and they are similar. A sparse model is effective for representing these image blocks. Therefore, a sparse model-based algorithm is proposed for surface moving target detection. In this algorithm, training sample image blocks are collected from a moving target video, and then a dynamic water background dictionary is trained by using KSVD and OMP algorithms based on sparse representation theory. In moving target detection, a frame image is divided into image blocks sequentially and the water surface background is reconstructed by a sparse model. The initial moving target image is calculated. Finally, the initial moving target image is processed without interference. The final moving target image is obtained. Experimental results show that the proposed algorithm is effective in detecting moving targets on the dynamic water surface.

Ensemble learning is a popular machine learning technique, which employs multiple learning methods to obtain better performance than any single constituent method. Recently, ensemble learning was successfully used in several bio-inspired optimization algorithms to achieve good performance. Artificial bee colony (ABC) is an efficient optimization technique inspired by the social behavior of bees. To enhance the optimization ability of ABC, this paper proposes a new ABC variant based on ensemble learning. The proposed approach is called multi-strategy and dimension perturbation ensemble of ABC (MPEABC), in which multiple distinct solution search strategies are used to balance the exploration and exploitation. To accelerate the search, each solution search strategy is assigned an independent probability to control the frequency of dimension perturbation. To avoid manually setting the probability, an adaptive method is used to dynamically adjust its value. Experimental verifications are conducted on a set of well-known benchmark functions. Results show that MPEABC achieves better solutions than the standard ABC, multi-strategy ensemble ABC (MEABC) and several improved ABC variants.

Multidrug and toxic compound extrusion (MATE) proteins are a group of secondary active transporters, which widely exist in all living organisms and play important role in the detoxication of endogenous secondary metabolites and exogenous agents. However, to date, no systematic and comprehensive study of this family is reported in maize. Here, a total of 49 MATE genes (ZmMATE) were identified and divided into seven groups by phylogenetic analysis. Conserved intro-exon structures and motif compositions were investigated in these genes. Results by gene locations indicated that these genes were unevenly distributed among all 10 chromosomes. Tandem and segmental duplications appeared to contribute to the expansion and evolution of this gene family. The Ka/Ks ratios suggested that the ZmMATE has undergone large-scale purifying selection on the maize genome. Interspecies microsynteny analysis revealed that there were independent gene duplication events of 10 ZmMATE. In addition, most maize MATE genes exhibited different expression profiles in diverse tissues and developmental stages. Sixteen MATE genes were chosen for further quantitative real-time polymerase chain reaction analysis showed differential expression patterns in response to aluminum treatment. These results provide a useful clue for future studies on the identification of MATE genes and functional analysis of MATE proteins in maize.

Cement and emulsified asphalt mortar (CA mortar) has been widely used as a filling layer between concrete bed plates and track slabs for high-speed railways. This study analyses the cracking mechanism of the interface between CA mortar and the concrete under CT treatment (cyclical temperature from −40 °C to 60 °C) and CTI treatment (cyclical temperature from −40 °C to 60 °C then immersed in water) by means of scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP), thermos-gravimetric analysis (TG) and differential thermal analysis (DTA). Results showed that cracks were observed on the interface after 16 CT cycles, while 25 cycles were required to observed cracks for sample under CTI treatment. The samples subjected to the CT treatment had a larger length difference between the CA mortar and concrete at high temperature. The volume proportion of 2–10 μm-level pore in CA mortar was declined after CT or CTI treatment, which was caused by removal of asphalt component in CA mortar from the matrix to the capillary porosity as confirmed by SEM results. CT treatment made it clear that the substance of low melting point in the asphalt either volatilized or turned into the substance of high melting point from TG and DTA analysis.

This study investigated the relationship between concrete electrical resistivity and compressive damage. The electrical resistivity and damage variable D of concrete under uniaxial compression were measured by the electrode method and ultrasonic method. The mathematical relationship between electrical resistivity and concrete damage variable D was derived. And the mechanism of change of concrete electrical resistivity under stress was explored by Nuclear Magnetic Resonance (NMR). The results showed that the electrical resistivity curve of concrete shows a phased trend of decreasing first and then increasing during loading, which corresponds to the damage evolution of concrete. The derived relationship between electrical resistivity and damage variable D is well correlated with the experimental data. Based on the NMR test results and considering the excess pore water pressure, it was found that the increase in connectivity of pore solution caused by the extruded pore solution filled cement matrix microcrack under stress may be the main reasons for the decrease in electrical resistivity of concrete specimens. Toward failure, the instability and penetration of macrocrack lead to the cutting of concrete matrix, which is the main reason for the increase of electrical resistivity.

Differential evolution (DE) is an excellent global optimizer, which has been used to optimize various engineering problems. In recent years, the radio frequency identification technology (RFID) has been applied to many fields. However, it is not an easy task to design an efficient RFID antenna. The antenna structure is usually complex and it is difficult to find a suitable parameter set. In this paper, we try to use DE to design a RFID antenna with Fibonacci sequence quasi Yagi structure. Simulation results show that DE can successfully design the antenna. The obtained antenna size is 30mm × 20mm. Its simulation center frequency is 60GHz and the center frequency gain approximates 8dB. In the frequency band 59.5-60.5GHz, the frequency echo loss is less than −10dB and the minimum value is −111dB.

The WRKY gene family, which encodes proteins in the regulation processes of diverse developmental stages, is one of the largest families of transcription factors in higher plants. In this study, by searching for interspecies gene colinearity (microsynteny) and dating the age distributions of duplicated genes, we found 35 chromosomal segments of subgroup I genes of WRKY family (WRKY I) in four Gramineae species (Brachypodium, rice, sorghum, and maize) formed eight orthologous groups. After a stepwise gene-by-gene reciprocal comparison of all the protein sequences in the WRKY I gene flanking areas, highly conserved regions of microsynteny were found in the four Gramineae species. Most gene pairs showed conserved orientation within syntenic genome regions. Furthermore, tandem duplication events played the leading role in gene expansion. Eventually, environmental selection pressure analysis indicated strong purifying selection for the WRKY I genes in Gramineae, which may have been followed by gene loss and rearrangement. The results presented in this study provide basic information of Gramineae WRKY I genes and form the foundation for future functional studies of these genes. High level of microsynteny in the four grass species provides further evidence that a large-scale genome duplication event predated speciation.

This study used detrended fluctuation analysis (DFA) and multifractal method to characterize the temporal fluctuations of the three pollution indices (SO2, NO2 and PM10) and the daily air pollution indices (APIs) of Shanghai in China. The results show that the temporal scaling behaviors in all the four series exhibit two different power laws. In shorter temporal scaling, all the series indicate the similar persistence corresponding to the annual cycle. However, in longer temporal scaling, the trends are different for the four series, which reflect the different inherent dynamic nature of various pollutant series. Furthermore, we investigated the frequency–size distribution of the four series. Our findings suggest that SO2, NO2 and PM10 pollution is an example of a self–organized criticality (SOC) process. The results represent that it is different SOC behaviors that result in the differences of power–law relations in these four series. This work can be helpful to understand the complex dynamic characteristics of APIs that can contribute to developing advanced techniques for air pollution forecasting.

Against the background of economic transformation and urban renewal, the protection and sustainable development of urban industrial landscapes has become an important practical issue, and how to maintain the unique local culture of these landscapes is key to solving the problem. By integrating the concept of “layer” and regarding the landscape as text, this paper will investigate the representation of industrial landscapes and the process of changes in power represented by different actors through different texts from the perspective of representation. The paper selected Beijing 798 as the research area to explore the shaping of changes in the industrial landscape of 798 from a weapon manufacturing area to an arts district, creative industry park and the “pan 798” by the factory owners, government, management committee, artists, media and tourists through different presentation forms, revealing the game process of representation of powers among the coalition between artists, management committee and the government. The paper points out that in fact, the representation of industrial landscape by different actors through different texts is a process that continues to explore and define the value of landscape. However, we need to look at this when the value of the industrial landscape is no longer given by localized life practices, but rather depends on different actors to produce and reproduce the value of landscape by representation, and thereby affecting the sustainable development of industrial landscape.

Extant literature concerns about industrial upgrading in developing countries, and stresses the importance of joining global production networks (GPN). Taking the perspective of the updating approach of GPN theory, this paper selects the case of China to combine local industrial upgrading with financial activities, and explores how going public triggers industrial upgrading in developing countries. In 2015, semi-structured interviews were conducted with 36 listed firms and their related partners in Jinjiang, a county-level city in China. The findings indicate that local lead firms in developing countries have been increasingly involved in the global financial market by going public, which in turn provides these countries with opportunities of industrial upgrading. However, it does not necessarily guarantee industrial upgrading. Whether or not going public can bring about industrial upgrading depends mainly on intrafirm coordination, reconfiguration of interfirm relationships, and extrafirm bargaining with local governments. This case study suggests that finance be integrated into GPN theory as some scholars suggest, and the impacts of local lead firms in developing countries on the dynamics or reconfiguration of GPN be taken consideration, especially in some specific sectors.