Accurate analysis of technological innovation mechanism in different regions is the key to promoting China’s technological innovation, economic transformation and upgrading. This paper collected ...statistical data of high-tech enterprises in 27 provinces in China from 2009 to 2016, established a novel PSO-GRNN model, and applied sensitivity analysis to explore the influencing factors and regional differences of enterprise technological innovation in Eastern, Central and Western China. The empirical results showed that the influencing factors were innovation investment, market environment, government support and foreign technology spillover sorting by impact size. Innovation investment was the decisive factor of technological innovation, but innovation resources mainly concentrated on Eastern China, severely insufficient in Central and Western China. Market environment was favorable to Eastern and Central China, but unfavorable to Western China, which restricted greatly the development of Western China. The principalagent problem of state-owned enterprise and the crowding out effect of government research and development funds jointly led to the negative influence of government support on technological innovation. Foreign technology spillover had significant positive effects on technological innovation in Western China. This paper clarifies some disputes about influencing factors of technological innovation and provides a new research perspective for related issues.
The reaction between persulfate (PS) and carbon nanotubes (CNTs) for the degradation of 2,4-dichlorophenol (2,4-DCP) was investigated. It was demonstrated that CNTs could efficiently activate PS for ...the degradation of 2,4-DCP. Results suggested that the neither hydroxyl radical (OH) nor sulfate radical (SO4−) was produced therein. For the first time, the generation of singlet oxygen (1O2) was proved by several methods including electron paramagnetic resonance spectrometry (EPR) and liquid chromatography mass spectrometry measurements. Moreover, the generation of the superoxide radical as a precursor of the singlet oxygen was also confirmed by using certain scavengers and EPR measurement, in which the presence of molecular oxygen was not required as a precursor of 1O2. The efficient generation of 1O2 using the PS/CNTs system without any light irradiation can be employed for the selective oxidation of aqueous organic compounds under neutral conditions with the mineralization and toxicity evaluated. A kinetic model was developed to theoretically evaluate the adsorption and oxidation of 2,4-DCP on the CNTs. Accordingly, a catalytic mechanism was proposed involving the formation of a dioxirane intermediate between PS and CNTs, and the subsequent decomposition of this intermediate into 1O2.
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•Non-radical mechanism for persulfate (PS) activation by using CNTs were demonstrated.•Generation of singlet oxygen (1O2) was proved by quenching experiments, ESR and LC-MS.•Selective oxidation of aqueous organic compounds was observed.•Kinetic model was established with a dynamic cycle proposed for the adsorption-oxidation of 2, 4-DCP.
The support vector machine is a new type of machine learning methods based on statistical learning theory. Because of good promotion and a higher accuracy, support vector machine has become the ...research focus of the machine learning community. This paper introduces the basic theory of support vector machine, the basic idea of the classification and currently used support vector machine classification algorithm. Practical problems with which an algorithm, and proves the effectiveness of the algorithm, the final outlook of the prospects of support vector machines in classification applications. Finally the prospect of the prospect of support vector machines in classification applications.
Air contamination is identified with individuals’ wellbeing and furthermore affects the sustainable development of economy and society. This paper gathered the time series data of seven ...meteorological conditions variables of Beijing city from 1 November 2013 to 31 October 2017 and utilized the generalized regression neural network optimized by the particle swarm optimization algorithm (PSO-GRNN) to explore seasonal disparity in the impacts of mean atmospheric humidity, maximum wind velocity, insolation duration, mean wind velocity and rain precipitation on air quality index (AQI). The results showed that in general, the most significant impacting factor on air quality in Beijing is insolation duration, mean atmospheric humidity, and maximum wind velocity. In spring and autumn, the meteorological diffusion conditions represented by insolation duration and mean atmospheric humidity had a significant effect on air quality. In summer, temperature and wind are the most significant variables influencing air quality in Beijing; the most important reason for air contamination in Beijing in winter is the increase in air humidity and the deterioration of air diffusion condition. This study investigates the seasonal effects of meteorological conditions on air contamination and suggests a new research method for air quality research. In future studies, the impacts of different variables other than meteorological conditions on air quality should be assessed.
SNARE proteins and Sec1 Munc18 (SM) proteins constitute the core molecular engine that drives nearly all intracellular membrane fusion and exocytosis. While SNAREs are known to couple their folding ...and assembly to membrane fusion, the physiological pathways of SNARE assembly and the mechanistic roles of SM proteins have long been enigmatic. Here, we review recent advances in understanding the SNARE-SM fusion machinery with an emphasis on biochemical and biophysical studies of proteins that mediate synaptic vesicle fusion. We begin by discussing the energetics, pathways, and kinetics of SNARE folding and assembly in vitro. Then, we describe diverse interactions between SM and SNARE proteins and their potential impact on SNARE assembly in vivo. Recent work provides strong support for the idea that SM proteins function as chaperones, their essential role being to enable fast, accurate SNARE assembly. Finally, we review the evidence that SM proteins collaborate with other SNARE chaperones, especially Munc13-1, and briefly discuss some roles of SNARE and SM protein deficiencies in human disease.
Generation of hydroxyl radicals in the Fenton system (FeII/H2O2) is seriously limited by the sluggish kinetics of FeIII reduction and fast FeIII precipitation. Here, boron crystals (C‐Boron) ...remarkably accelerate the FeIII/FeII circulation in Fenton‐like systems (C‐Boron/FeIII/H2O2) to produce a myriad of hydroxyl radicals with excellent efficiencies in oxidative degradation of various pollutants. The surface B−B bonds and interfacial suboxide boron in the surface B12 icosahedra are the active sites to donate electrons to promote fast FeIII reduction to FeII and further enhance hydroxyl radical production via Fenton chemistry. The C‐Boron/FeIII/H2O2 system outperforms the benchmark Fenton (FeII/H2O2) and FeIII‐based sulfate radical systems. The reactivity and stability of crystalline boron is much higher than the popular molecular reducing agents, nanocarbons, and other metal/metal‐free nanomaterials.
The unique B12 unit of crystalline boron experiences step‐wise cleavage of B−B bond and rapidly provides electrons for FeIII reduction to FeII. This boosts the oxidation capability of the Fenton systems remarkably to oxidize a diversity of organic pollutants with exceptional stability.
Abstract
To reduce the gas disaster of high gas coal seam and improve the efficiency of gas extraction by high drilling, the layout parameters of drilling holes in Pingdingshan coal mine are ...optimized. Based on the analysis and calculation of the "three zones" of the movement towards the overly strata of No.10 coal in Pingdingshan coal mine, the height of caving zone and fissure zone in 24,130 working face are 10.06–14.46 m and 38.75–49.95 m respectively. The elevation angle, azimuth angle and the length of high-level boreholes are studied and analyzed by COMSOL numerical simulation software. The simulation results show that the optimum layout parameters of high-level boreholes are as follows: The elevation angle of borehole should be controlled at 9°–12°, the azimuth angle should be 30°–45°, and the length of borehole should be 150 m. Then the optimum layout parameters of high-level boreholes are determined for engineering application of 24,130 working face. Borehole data onto actual mine show that the optimum layout parameters of high-level boreholes were elevation angle between 8°and 11°, azimuth angle between 30° and 42°, and length of boreholes between 145 and 155 m. The simulation results are basically consistent with the measured data. The maximum gas concentration in working face, upper corner and return air roadway is stably controlled below 1%. The safe mining of 24,130 working face is ensured, which provided a certain reference value of gas control in the goaf of Pingdingshan mine and adjacent mines.
This study focuses on the Tianshifu Basin, eastern Liaoning, China, which is filled with Lower–Middle Jurassic fluviolacustrine sediments rich in macroplants. Our aim is to explore the continental ...climate features of the late Early Jurassic period. The composition of the Early–Middle Jurassic flora and the carbon isotopic ratios of organic matter, total organic carbon, total organic nitrogen and sulphur of the rock samples from the Changliangzi section (the upper part of the Lower Jurassic deposits) have been investigated. Based on the flora, eastern Liaoning was generally characterized by temperate and humid conditions during the Early–Middle Jurassic period, but with rising temperatures during late Early Jurassic time. The sediments of the Changliangzi section show a transformation from shallow-lake facies to deep-lake facies. A positive organic carbon isotope excursion correlates with the deepening of this palaeolake, considered to be caused by climate warming. The late Early Jurassic climate warming indicated by floral and isotopic evidence corresponds to the climatic events recorded elsewhere in marine and continental sequences during the Toarcian Age, the so-called Toarcian Anoxic event, and may be associated with enhanced global greenhouse warming. This study provides new continental data supporting global warming during the late Early Jurassic period.
This paper studied the mechanical behaviors of unidirectional flax and glass fiber reinforced hybrid composites with the aim of investigation on the hybrid effects of the composites made by natural ...and synthetic fibers. The tensile properties of the hybrid composites were improved with the increasing of glass fiber content. A modified model for calculating the tensile strength was given based on the hybrid effect of tensile failure strain. The stacking sequence was shown to obviously influence the tensile strength and tensile failure strain, but not the tensile modulus. The fracture toughness and interlaminar shear strength of the hybrid composites were even higher than those of glass fiber reinforced composites due to the excellent hybrid performance of the hybrid interface. These macro-scale results have been correlated with the twist flax yarn structure, rough surface of flax fiber and fiber bridging between flax fiber layers and glass fiber layers.
The development process of coal spontaneous combustion in the actual site is very complex, and the spontaneous combustion process is affected by many factors. One of the key points is the temperature ...change of fire source. In the actual working conditions, the location of fire source is often hidden and difficult to find, making it difficult to track and determine the direction and region of temperature change. Therefore, in the experimental environment of room temperature and room pressure, the temperature of coal spontaneous combustion is monitored, and the temperature change law under the inclined placement mode is analyzed to determine the high temperature area and its spread fuzzy path, and further analyze the influence of fire air pressure on the temperature change in the high temperature area. The study shows that the spread of high temperature area is nonlinear, mainly along the central and southeast direction of the furnace body. In the early stage of the experiment, the influence of temperature on t
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