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Urban agglomeration (UA) is an advanced spatial economic form formed and developed in the process of rapid industrialization and urbanization, and an important carrier of urbanization and economic development. The economy has developed rapidly in the recent decades of China, and the UAs have also developed rapidly. However, as a large population country, the population distribution and changes of UAs in China has unique characteristics. Using the fifth, sixth and seventh population census data, spatial auto-correlation and spatial econometric models, we analyzed the spatial-temporal evolution characteristics and influencing factors of population agglomeration in China’s UAs. Results revealed that: 1) from 2000 to 2020, the population gradually converged into UAs, and the characteristics of population agglomeration in different development degree of UAs differ. The higher the development degree of UA, the higher the population agglomeration degree. Besides, UAs are the main area with the most significant population agglomeration degree, and the spatial autocorrelation show that the cities with similar degree tend to be concentrated in space. The urban population gathering in UAs has a certain positive spillover effect on population size of neighboring cities. 2) Economic development and social conditions factors are important factors affecting population agglomeration degree in UAs. The main factors of population gather into UAs are similar with the outside UAs, but the positive promotion of urbanization rate and proportion of tertiary industry in GDP on population agglomeration of UAs in China are enhancing from 2000 to 2020. Meanwhile, the other factors, such as high-quality public services, good urban living environment conditions, high-quality medical and educational resources, are also important factors to promote urban population gather into UAs. This study provides a basis for formulating the development planning of UAs in China, and enriches the relevant theoretical research of population evolution and influencing factors of UAs.

There has been a longstanding debate about the impact of international trade on the environment and human well-being, yet there is little known about such environment and human well-being trade-off. Here, we explore the effect of international trade on the carbon intensity of human well-being (CIWB) globally under the current global trade system and a hypothetical no-trade scenario. We found that between 1995 and 2015, CIWB of 41% of countries declined and 59% of countries increased, caused by international trade, and this resulted in a reduction of the global CIWB and a decline in CIWB inequality between countries. International trade decreased CIWB for high- and upper-middle-income countries and increased CIWB for lower- and middle-income countries. In addition, our results also show that decreases in emission intensity are the most important driver of lower CIWB and the percentage contribution of emission intensity to the improvement in CIWB increases with income. The reduction of emission intensity, population growth, and increase in life expectancy all contribute to CIWB reduction, while the consumption level is the primary factor driving CIWB growth. Our results underscore the importance of studying the impact of international trade on the CIWB of countries at different stages of development.

The vigorous development of information and communications technology has accelerated reshaping of the financial industry. The COVID-19 pandemic has further catalyzed the demand for digital financial services. Digital financial inclusion relies on information technology to overcome spatial limitations. In this case, the research question is whether it adheres to the spatial laws governing conventional financial activities. This study uses exploratory spatial data analysis and a geographical detector to elucidate the spatiotemporal characteristics and factors influencing digital financial inclusion at the county level in China (Data don’t include that of Hong Kong, Macao and Taiwan of China) from 2014 to 2020. The research findings indicate: first, China’s county-level digital financial inclusion is generally increasing and exhibits significant spatial autocorrelation. Second, population density, level of traditional financial development, government regulation, and education level are key determinants of China’s county-level digital financial inclusion. Third, policies should be differentiated by region to narrow the spatial gap in digital financial inclusion. The results provide a reference for other developing countries on using digital technology to develop financial inclusion.

Efforts to stabilize the global climate change while also continuing human development depend upon “decoupling” economic growth from fossil fuel CO2emissions. However, evaluations of such decoupling have typically relied on production-based emissions, which do not account for emissions embodied in international trade. Yet international trade can greatly change emissions accounting and reshape the decoupling between emissions and economic growth. Here, we evaluate decoupling of economic growth from different accounts of emissions in each of the 159 countries and analyze the drivers of decoupling. We find that between 1995 and 2015, although 29 countries exhibited strong decoupling of territorial emissions (growing economies and decreasing emissions), only 19 countries achieved economic growth while their consumption-based emissions decreased. Most developed countries have achieved decoupling of emissions related to domestic goods and services, but have not achieved decoupling of emissions related to imported goods and services. The U-test confirms that the domestic component of consumption-based emissions exhibits a stronger decoupling trend from gross domestic product (GDP) growth than consumption-based emissions, and emissions from imports continue to rise with GDP per capita without a corresponding decline, providing a statistical validation of the decoupling analysis. Moreover, in the countries where economic growth and consumption-based emissions are most decoupled, a key driver is decreasing emissions intensity due to technological progress─and especially reductions in the intensity of imported goods and services. Our results reveal the importance of assessing decoupling using consumption-based emissions; successful decoupling may require international cooperation and coordinated mitigation efforts of trading partners.

This paper explores the factors affecting newly increased construction land (NCL) in China at different development stages based on supply figures for the land market in 2010–2015. The results reveal that with the progress of regional development, NCL gradually increases, whereas the dependence of regional development on NCL decreases. Moreover, the structure of NCL at different development stages differs significantly. Nonagricultural industry development, land resource scarcity, population growth, economic extroversion, and domestic capital have different effects on NCL at different stages of development. These differences are closely related to the socioeconomic characteristics of each development stage. These findings may enrich the study of urban expansion in China's economic transition. This paper suggests that the government should be aware of regional differences in NCL regulation.

It is imperative to have an in-depth understanding of the chemical inhibition mechanism for spontaneous combustion of coal, not only for controlling and preventing spontaneous combustion of coal in the coal mining industry but also for reducing emissions of hazardous gases. N,N-dibenzylhydroxylamine (DBHA) as a hydroxylamine free radical scavenger can be chosen as a feasible stabilizer for the spontaneous combustion of coal. In this study, the inhibitory performance of DBHA was examined by investigating coal mass changes and heat release obtained from thermogravimetric and differential scanning calorimetry. The effect of DBHA on change of the active groups during coal oxidation at different temperatures was determined by in situFourier-transform infrared spectroscopy. Density functional theory was also introduced to optimize the active radical model and calculate thermodynamic parameters. Experimental results showed that DBHA exerted a strong inhibitory effect on the spontaneous combustion of coal, especially for lignite and sub-bituminous coal. DBHA can combine with a hydroperoxide intermediate to form a stable compound, causing the effect of reducing the free hydroxyl content in coal and interrupting the formation of aldehydes and carboxylic acids. Additionally, it can combine with alkyl radicals to form stable compounds. DBHA exhibits an inhibitory effect by increasing the activation energy at each stage, especially during the accelerated oxidation and quick oxidation stages. Furthermore, the possible reaction paths between free radicals and DBHA were also proposed on the basis of the experimental findings.

Many studies have qualitatively explained that information and communication technology (ICT) has loosened the restrictions of distance and space on retailers’ sales. Few empirical studies, however, have explored the impact of shipping distance on online retailers’ sales. This study examined the Maiyang (M-Y) store on Tmall in China as a case study to investigate the relationship between shipping distance and sales. The results showed that sales volume in 2014 at the county level did not strictly obey the distance decay law. The shipped distance of high-priced commodities may not be much longer than that of low-priced commodities. Within the scope of investigation, the relationships between income, cost, and net profit curves do not follow central place theory. Goods have neither thresholds nor ranges. The key factor in the spatial discrepancy of sales is the size of market. The impact of shipping distance on sales is not as strong as that of traditional retailers in Information Era.

In this work, we reported a valid method to sort large-diameter semiconducting single-walled carbon nanotubes (sc-SWCNTs) from commercial arc discharge SWCNTs by different conjugated organic compounds. Seven kinds of high-purity sc SWCNT inks were achieved. As-prepared sc-SWCNT inks were directly used to fabricate printed SWCNT TFT arrays and backplane circuits on rigid substrates. It was found that printed SWCNT TFT devices exhibited high-performance with low operating voltage (±2 V), small subthreshold swing (ss), small hysteresis, high mobility (more than 20 cm2/Vs) and high on/off ratios (up to 106). Printed 2T-1C driving circuit exhibited high on/off ratio up to 105and high output current up to 8×10-5µ A at Vdata, Vscanand Vddof -2 V, respectively. Furthermore, 15×15 OLED pixel arrays were switched on with printed SWCNT driving circuits on glass substrates, suggesting printed SWCNT driving circuits have the potential as backplanes for active matrix OLED applications.

The fabrication of printed high-performance and environmentally stable n-type single-walled carbon nanotube (SWCNT) transistors and their integration into complementary (i.e., complementary metal–oxide–semiconductor, CMOS) circuits are widely recognized as key to achieving the full potential of carbon nanotube electronics. Here, we report a simple, efficient, and robust method to convert the polarity of SWCNT thin-film transistors (TFTs) using cheap and readily available ethanolamine as an electron doping agent. Printed p-type bottom-gate SWCNT TFTs can be selectively converted into n-type by deposition of ethanolamine inks on the transistor active region via aerosol jet printing. Resulted n-type TFTs show excellent electrical properties with an on/off ratio of 106, effective mobility up to 30 cm2V–1s–1, small hysteresis, and small subthreshold swing (90–140 mV dec–1), which are superior compared to the original p-type SWCNT devices. The n-type SWCNT TFTs also show good stability in air, and any deterioration of performance due to shelf storage can be fully recovered by a short low-temperature annealing. The easy polarity conversion process allows construction of CMOS circuitry. As an example, CMOS inverters were fabricated using printed p-type and n-type TFTs and exhibited a large noise margin (50 and 103% of 1/2 Vdd= 1 V) and a voltage gain as high as 30 (at Vdd= 1 V). Additionally, the CMOS inverters show full rail-to-rail output voltage swing and low power dissipation (0.1 μW at Vdd= 1 V). The new method paves the way to construct fully functional complex CMOS circuitry by printed TFTs.

The middle class in metropolitan Chinese cities has become an important social group. With the rapid development of urbanization and constant advancement of suburbanization, the middle class has increasingly come to influence city traffic. Research into middle-class commuting activities thus has practical significance for improving traffic congestion and reducing the commuting burden in metropolitan cities. Based on a dataset formed by 816 completed surveys, this paper analyzes the commuting mode, time and distance of middle-class residents in Guangzhou City using the descriptive statistical method. The results indicate that private cars are the main commuting mode, followed by public transport. Meanwhile, middle-class residents mainly undertake medium-short time and medium- short distance commuting. The study subsequently uses multilevel logistic regression and multiple linear regression models to analyze the factors that influence commuting mode choice, time and distance. The gender, age, number of family cars, housing source and jobs-housing balance are the most important factors influencing commuting mode choice; housing, population density, jobs-housing balance and commuting mode significantly affect commuting time; and transport accessibility, jobs-housing balance and commuting mode are the notable factors affecting commuting distance. Finally, this paper analyzes what is affecting the commuting activities of middle-class residents and determines the differences in commuting activity characteristics and influence factors between middle-class and ordinary residents. Policy suggestions to improve urban planning and urban management are also proposed.

Principal components analysis of small-area data provided by China's 2000 Population Census shows that major new economic and social forces largely shape the spatial composition of housing in Guangzhou. This is generally manifested in a series of concentric rings: the old urban core, the middle zone of reform housing, and the outer ring of new commodity housing. In addition, urban villages punctuate the metropolitan landscape. Corresponding analysis of sociodemographic attributes depict a metropolis in transition, with market elements and choice-based housing decisions beginning to impinge on the urban fabric. However, the deeply entrenched socialist institutions established during the early years of the People's Republic ensure the continuing dominance of the workplace and occupational attributes as factors structuring China's metropolitan space.

A normal-phase-HPLC method for determining individual xanthates in mixtures is presented. The quantitative analyses have been carried out after separation on a LiChrosorb-Diol column using the non-polar solvent n-hexane as mobile phase and UV-detection at 254 nm. The developed HPLC procedure possesses a high sensitivity and high speed of analysis, especially for xanthates with longer alkyl chains. This method was applied to the determination of xanthates in technical flotation liquors. Relative standard deviations for contents of 0.6×10-5 mol/l to 1.2×10-5 mol/l were 2.76 to 5.45%. The absolute limit of determination for potassium octyl xanthate is 0.2 ng.

Two HPLC methods for the determination of individual alkyl xanthates in mixtures are described. They are based on the formation of copper xanthate complexes and the oxidation of xanthates to dixanthogens, respectively. The reversed-phase chromatographic behaviour of both types of compounds together with the optimization of separation and determination conditions are discussed in detail. It is shown by several determinations of synthetic and practical flotation samples that the two methods provide an identical reliability for the analysis of xanthates and could complement each other. The detection limits (301 resp. 240 nm) are as low as 3.1 · 10-8 mol/l (metal xanthate complexes) and 1.6 · 10-8 mol/1 (dixanthogens). The methods described are suitable for flotation, chemical industry and environmental analysis.

The applied catalytic system can be recycled at least four times.

The used PYIM ligand is prepared in a three‐step synthesis.