The characteristics and countermeasures of coupled and coordinated development between technological innovation and ecological environment in China's Gansu province.

The investigation of the coupling and coordination association between scientific and technological innovation and the eco-environmental system is of vital practical significance for promoting the high-quality economic development of China's Gansu province. The evaluation index system is constructed based on the explanation of the coupling and coordination mechanism of a "Binary system". Subsequently, a comprehensive evaluation model is developed using the entropy method, whereas the coupling coordination relationship between "Binary systems" is analyzed in the context of the coupling coordination degree model. The study findings indicate that the innovation drive has become the primary driving force that leads the high-quality economic development in Gansu province. Furthermore, the comprehensive development level and coupling and coordination degree of all systems in Gansu province demonstrate a sound trend of steadily rising. Additionally, there is an issue of uncoordinated development between scientific and technological innovation and eco-environment systems in Gansu province. Thus, this research study proposes certain policy suggestions, such as optimizing the environment of Sci-tech innovation, insisting on the priority of ecology, increasing the input of Sci-tech innovation, and building up a contingent of talents.

Nickel/photoredox-catalyzed enantioselective arylation of α-chloro thioesters.

The first dual nickel/photoredox-catalyzed enantioselective reductive cross-coupling of racemic α-chloro thioesters with aryl iodides has been developed. This strategy avoids the need for organometallic reagents or stoichiometric metal reductants. This reaction could tolerate a wide range of substrate scope with excellent reactivity and high enantioselectivities (up to 91% ee) to access a variety of chiral α-aryl thioesters. The synthetic utility of the corresponding α-aryl thioesters is demonstrated. Furthermore, we explored the mechanism of such an enantioselective radical cross-coupling process.

Construction of Macromolecules of Depolymerized Lignite.

Preparing ash-less coal and further converting it into chemicals is an efficient and promising means for lignite utilization. This work performed depolymerization of lignite to prepare ash-less coal (SDP) and separated it into the hexane-soluble fraction (HS), toluene-soluble fraction (TS), and tetrahydrofuran-soluble fraction (THFS). The structure of SDP and those of subfractions were characterized by elemental analysis, gel permeation chromatography, Fourier transform infrared spectroscopy, and synchronous fluorescence spectroscopy. The results show that SDP is a mixture of aromatic derivatives containing alkyl substituents and oxygen-containing functional groups. The number of condensed aromatic rings, the amount of oxygen-containing functional groups, and the molecular weight gradually increase as HS < TS < THFS. SDP was further analyzed by 1H-NMR and 13C-NMR to calculate its structural parameters. The macromolecule of THFS contains 15.8 total ring systems with 9.2 aromatic rings and 6.6 naphthenic rings. On average, each THFS molecule contains 6.1 alcohol hydroxyl groups, 3.9 phenol hydroxyl groups, 1.4 carboxyl groups, and 1.0 inactive oxygen-containing functional groups. The dominant reactions occurred during depolymerization are the breakage of ether linkages. The average THFS molecule consists of 3.3 structural units with aromatic nuclei (2.8 rings on average) linked with methylene, naphthene, and so forth.

The Threshold Effect of Knowledge Diversity on Urban Green Innovation Efficiency Using the Yangtze River Delta Region as an Example.

Green innovation in the Yangtze River Delta is closely related to higher-quality integrated development, and knowledge diversity is crucial to the realization of regional green technology innovation and development. This study measured the green innovation efficiency of cities in the Yangtze River Delta region from 2010 to 2018 utilizing the Super-SBM model based on undesired outputs. In addition, this study used patent data to investigate regional knowledge deversity, including related variety, and unrelated variety, and to examine the spatio-temporal characteristics of green innovation efficiency and the threshold effect of knowledge diversity. The results demonstrated that related variety was positively correlated with the efficiency of urban green innovation, which was in line with extant studies. Unrelated variety was accompanied by an increase in urban science and technology investment and expansion of urban scale, and the negative effect of knowledge unrelated variety was significantly weakened. This study deepened the understanding of the mechanism of action of diversity, which is conducive to the sustainable development goals as regards the formulation of policies related to green innovation and the development of various types of cities.

China's Outward Direct Investment in the United States: From the perspective of agglomeration economies.

Over most of the last two decades, China's Outward Direct Investment (CODI) has reshaped the global economic landscape and attracted considerable attention. Although extensive research shows that CODI features agglomeration, there is limited research from the perspective of different patterns of agglomeration economies at the subnational level. It is unclear which patterns of agglomeration economies play a role in the location choice of CODI, especially with the variations of CODI in terms of entry mode and ownership. Therefore, based on the data of the CODI in the United States in the period 2000-2016, we use a conditional logit model to investigate the influence of specialized and diversified agglomeration of local firms as well as industry-specific and industry-diverse agglomeration of Chinese investors on the location choice of CODI, and further explore the heterogeneous influence concerning the entry mode and ownership. Our results show that among a variety of agglomeration economies, the specialized agglomeration of local firms is the premier factor influencing the location choice of CODI, even exceeding the influence of industry-specific agglomeration of CODI in the same industry. Industry-diverse agglomeration of CODI plays a weak role, while diversified agglomeration of local firms has no effect. Moreover, the location choice of acquisition is more sensitive to the specialized agglomeration of local firms than that of greenfield investment, and the influence of the industry-diverse agglomeration of CODI has no effect on the location choice of acquisition. In terms of the ownership, the location choice of state-owned enterprises (SOEs) is more sensitive to the specialized agglomeration of local firms and industry-specific agglomeration of CODI than that of private investment, and the industry-diverse agglomeration of CODI has no significant impact on the location choice of SOEs' offshoring subsidiaries.

Spatiotemporal Response of Hydrological Drought to Meteorological Drought on Multi-Time Scales Concerning Endorheic Basin.

Under the controversial background of "Northwestern China is gradually developing towards warm and humid", how hydrological drought responds to meteorological drought at the endorheic basin is of great significance. To address this problem, we first analyzed the spatiotemporal variation of meteorological and hydrological droughts at Tarim Basin River from 1960 to 2014 by using the daily standardized precipitation index (SPI) and daily standardized terrestrial water storage index (SWSI) based on the reanalysis data. Thereafter, we explored the spatiotemporal response of hydrological drought to meteorological drought on the multi-time scale by using the cross-wavelet transform method, Ensemble Empirical Mode Decomposition (EEMD), and correlation analysis. We find that: (1) both meteorological and hydrological droughts signified a gradually weakened trend in time; (2) meteorological and hydrological drought have significant resonance periods on the 10-month time scale and the 8-year time scale; (3) hydrological drought generally lags behind the meteorological drought by 7 days in plains areas, while it can last as long as several months or even a year in mountainous areas.

Spatio-temporal evolution and mechanism of regional innovation efficiency: Evidence from Yangtze River Delta Urban Agglomeration of China.

Regional innovation is an important research topic in economic geography, the spatio-temporal evolution and mechanism of regional innovation efficiency have recently become a hot for economic geographers. From the perspective of input and output efficiency, this paper constructs evaluation indicator of regional innovation, with the help of Constant Returns to Scale (CRS) and Variable Returns to Scale (VRS) models, and Malmquist indicator method of Data Envelopment Analysis (DEA), to analyze regional innovation performance, evolution trend, spatial differentiation, and evolution mechanism of Yangtze River Delta Urban Agglomeration (YRDUA) of China. The results show that: (i) Innovation efficiency of YRDUA is generally low, most of which is less than 80 percent of optimal efficiency; however, it kept rising from 2000 to 2015. (ii) Spatial inequality of regional innovation in YRDUA is significant, with a spatial pattern in the shape of "Z", composed by Hefei, Nanjing, Shanghai, Hangzhou and Ningbo, innovation efficiency of Shanghai is higher than Zhejiang, Anhui and Jiangsu. (iii) Technology progress is the most important influencing factor, all kinds of changing indicator show a trend of rise, and the total factor productivity is changing significantly. This research can provide theoretical reference for the YRDUA to achieve high-quality integration.

Does Technological Innovation Promote Green Development? A Case Study of the Yangtze River Economic Belt in China.

The role of technological innovation (TI) in green development is controversial. Based on 2003-2017 panel data of 108 cities in the Yangtze River Economic Belt (YREB), this study constructed an index system to evaluate urban green development and analyzed the role of TI on urban green development with the help of a panel econometric model. The results show that: (1) From 2003 to 2017, the levels of TI and green development of cities in the YREB have gradually improved, but the core-periphery structure is obvious, and the levels of TI and green development in the lower reaches are significantly higher than those in the middle and upper reaches. (2) TI has a significant positive role in promoting green development, showing a U-shaped nonlinear relationship, and this relationship varies from region to region. (3) TI has a significant impact on green development with direct and indirect effects. In the economic and social dimensions, TI has a positive impact on green development, while in the ecological dimension, the direct effect and indirect effect have opposite relationships. (4) TI has a significant threshold effect on green development, and there are differences in threshold characteristics between the three dimensions. These findings provide a scientific basis for policymaking about innovation-driven regional green development, and it can enrich the related theories of environmental economic geography.

The characteristics of spatial expansion and driving forces of land urbanization in counties in central China: A case study of Feixi county in Hefei city.

Urbanization in Central and Western China has attracted increasing attention in the advent of new-type urbanization in China and the age of 'Global Urbanism'. Although land urbanization is at the epicenter of Chinese urbanization, its process and driving forces in counties beyond the Eastern coastal areas are less known. This paper therefore seeks to investigate the spatial expansion and driving forces of land urbanization in Feixi county, a relatively advanced county neighboring Hefei city proper in Anhui province in Central China. Based on the land-use change survey data, remote sensing interpretation data, and statistical yearbook data of Feixi county from 2002 to 2016, it is revealed that the overall scale of urban land in Feixi county increased remarkably, though with obvious temporal and geographical variants. The year 2009 appears to be the cutting line between quantity-based land urbanization and quality-based land urbanization. Land urbanization rate is sensitive to both geographical distance and traffic accessibility to Hefei city proper. Driving forces of land urbanization in Feixi county are summarized as: (1) central city expansion, (2) government-led industrial park construction, and (3) large industrial projects along traffic corridors. A better understanding of urbanization in Feixi county cannot be fulfilled without taking into account the wider spatial process in Hefei city and the Yangtze River Delta city-region.

The effects of external knowledge source heterogeneity on enterprise process and product innovation performance.

As a global manufacturing centre, China is transitioning from a 'Made in China' to 'Create in China' perspective. An ever-increasing number of companies are developing new competitive advantages and improving their innovation levels by acquiring external knowledge. Yet, studies rarely discuss the influence of various sources of knowledge on process and product innovation performance in China's manufacturing enterprises. Based on the Pavitt industry classification, we use a bivariate Probit model to investigate the influence of external knowledge sources on innovation performance, and test it by using Enterprise Survey data for China, published by the World Bank in 2013. Our empirical analysis indicates that external sources of knowledge, with the exception of suppliers, have a significantly positive influence on process and product innovation performance. Specifically, in the process of technological innovation, peers have a positive effect on enterprise process improvement, especially in the science-based sector. In product innovation, close technical cooperation with users accelerates the commercial manifestation of products, especially in the specialized supplier sector.

One-Pot Aminoalkylation of Aldehydes: Diastereoselective Synthesis of Vicinal Diamines with Azaarylmethylamines.

A one-pot synthesis of vicinal diamines with azaarylmethylamines and aldehydes is reported. A diverse array of vicinal diamines could be achieved in up to 92% yield with good to excellent diastereoselectivities (up to 20:1). The tandem reaction takes place under mild conditions and provides an alternative strategy for the synthesis of vicinal diamines.

Adsorption performance of Cd(II), Cr(III), Cu(II), Ni(II), Pb(II) and Zn(II) by aminated solution-blown polyacrylonitrile micro/nanofibers.

In this work, we prepared amidoxime-functionalized polyacrylonitrile (APAN) micro/nanofibers by modifying solution-blown PAN fibers with hydroxylamine hydrochloride, and investigated the adsorption performance of the APAN fibers for Cd(II), Cr(III), Cu(II), Ni(II), Pb(II) and Zn(II) from aqueous solutions. Batch experiments and quantitative analysis were conducted considering initial pH and contact time as controlling parameters. The equilibrium data were better explained by the Langmuir model with maximum adsorption capacities of 185, 204, 105, 104, 345 and 91 mg/g for Cd(II), Cr(III), Cu(II), Ni(II), Pb(II) and Zn(II), respectively. The adsorption kinetics were found to follow the pseudo-second-order kinetic model. The calculated thermodynamic parameters demonstrated that the adsorption of metal ions onto APAN fibers is feasible, spontaneous and endothermic. The five adsorption-desorption cycle experiments showed that APAN micro/nanofiber adsorbent exhibits good reusability, and has a potential application for the removal of heavy metals from wastewater.

Elucidating the removal mechanism of N,N-dimethyldithiocarbamate in an anaerobic-anoxic-oxic activated sludge system.

N,N-Dimethyldithiocarbamate (DMDTC) is a typical precursor of N-nitrosodimethylamine (NDMA). Based on separate hydrolysis, sorption and biodegradation studies of DMDTC, a laboratory-scale anaerobic-anoxic-oxic (AAO) system was established to investigate the removal mechanism of DMDTC in this nutrient removal biological treatment system. DMDTC hydrolyzed easily in water solution under either acidic conditions or strong alkaline conditions, and dimethylamine (DMA) was the main hydrolysate. Under anaerobic, anoxic or oxic conditions, DMDTC was biodegraded and completely mineralized. Furthermore, DMA was the main intermediate in DMDTC biodegradation. In the AAO system, the optimal conditions for both nutrient and DMDTC removal were hydraulic retention time 8 hr, sludge retention time 20 day, mixed-liquor return ratio 3:1 and sludge return ratio 1:1. Under these conditions, the removal efficiency of DMDTC reached 99.5%; the removal efficiencies of chemical organic demand, ammonium nitrogen, total nitrogen and total phosphorus were 90%, 98%, 81% and 93%, respectively. Biodegradation is the dominant mechanism for DMDTC removal in the AAO system, which was elucidated as consisting of two steps: first, DMDTC is transformed to DMA in the anaerobic and anoxic units, and then DMA is mineralized to CO2 and NH3 in the anoxic and oxic units. The mineralization of DMDTC in the biological treatment system can effectively avoid the formation of NDMA during subsequent disinfection processes.

Treatment of tetrahydrofuran wastewater by the Fenton process: response surface methodology as an optimization tool.

In this study, the Box-Benkhen design and response surface method (RSM) were applied to evaluate and optimize the operating variables during the treatment of tetrahydrofuran (THF) wastewater by Fenton process. The four factors investigated were initial pH, Fe(2+) dosage, H2O2 dosage and reaction time. Statistical analysis showed the linear coefficients of the four factors and the interactive coefficients such as initial pH/Fe(2+) dosage, initial pH/H2O2 dosage and Fe(2+) dosage/H2O2 dosage all significantly affected the removal efficiency. The RSM optimization results demonstrated that the chemical oxygen demand (COD) removal efficiency could reach up to 47.8% when initial pH was 4.49, Fe(2+) dosage was 2.52 mM, H2O2 dosage was 20 mM and reaction time was 110.3 min. Simultaneously, the biodegradability increased obviously after the treatment. The main intermediates of 2-hydroxytetrahydrofuran, γ-butyrolactone and 4-hydroxybutanoate were separated and identified and then a simple degradation pathway of THF was proposed. This work indicated that the Fenton process was an efficient and feasible pre-treatment method for THF wastewater.