Innovation contributes to the long-term economic growth. From the perspective of externality by innovation, this paper disentangles the spillover effect based on the regions’ abundance of innovation resource and separately identifies the “leader effect” and “peer effect” of innovation spillover and discusses their economic consequences. Empirical results demonstrate a negative spillover effect from innovation leaders on the economic growth and a positive spillover effect from innovation peers. Robustness checks also support main findings. This study has implication both in the endogenous economic growth theory and industry innovation practice.
Interfacial modification as a feasible strategy to improve the properties of perovskite solar cells (PSCs) has been widely studied in recent years. In this work, PbCl2 modification at the interface of SnO2/CH3NH3PbI3 was used for CH3NH3PbI3-based planar PSCs. The introduction of PbCl2 between SnO2 and CH3NH3PbI3 layers boosted the crystallization of perovskite film, which promoted the photovoltaic properties of corresponding PSCs. The open circuit voltage (VOC) and fill factor (FF) of the PbCl2-modified devices (1 mg/mL) were 1.11 V and 0.79, respectively, which were both higher than those of the reference devices without PbCl2 (1.04 V and 0.76). Moreover, a steady-state power output efficiency exceeding 19% was obtained for the PbCl2-modified devices (1 mg/mL), which implied that PbCl2 modification was an effective and low cost strategy for efficient PSCs.
In this paper, we present a scalable and general fabrication for micro-supercapacitors (MSCs) among various flexible substrates assisted by the stamp, which combines the conductive polymer composites with gravure printing process. Compared with the traditional transferring techniques, this method greatly simplifies the process and mitigates the mechanical damage during the preparation. Profiting from the composites of carbon nanotubes (CNTs) and polydimethylsiloxane (PDMS) as the printing inks, the MSCs exhibit elegant areal capacitance (10.491 μF/cm2) on the paper substrate. Meanwhile, optimizing the ratio of matrix and curing agent of PDMS, the interaction between ink and substrate is effectively enhanced. Therefore, such novel fabrication technology significantly improves the production efficiency as well as broadens the applications.
Understanding and controlling confined CO2 fluids in nanopores is at the heart of the CO2 enhanced oil recovery in shale reservoirs. Here, for the first time, qualitative and quantitative static and dynamic behavior of complex confined CO2 fluids in dual-scale nanopores are experimentally performed in nanofluidics, which combines with the theoretical model, the statistical mechanics coupled with the thermodynamic equation of state, to investigate the CO2 utilization in shale reservoirs. In experiment, a series of phase behavior and fluid flow laboratory tests are conducted through a self-manufactured nanofluidic system at different conditions; in theory, a generalized equation of state including the confinements and pore-size distributions and five dynamic models are developed and applied to calculate the vapor–liquid equilibrium and fluid dynamics. Results from this study show that the static behavior has drastic changes in the dual-scale nanopores that the measured saturation pressure of the confined CO2–C10 fluids reduces by 10.19% at T = 25.0 °C and 7.26% at T = 53.0 °C from bulk phase to nanometer scale. Furthermore, under the strong confinements in the dual-scale nanopores, the calculated phase properties including the pore-size distribution effects are more accurate. In addition, effects of the temperature and feed gas to liquid ratio on the confined fluids in nanopores share similar manners with the bulk phase cases. The proposed theoretical models are capable of calculating the static and dynamic behavior of the confined fluids and all calculations have been validated by the experimentally measured results. This study supports the foundation of more general applications pertaining to producing shale fluids and sequestrating CO2 in shale reservoir characterization and exploration.
Dissymmetric reactions, which enable differentiated functionalization of equivalent sites within one molecule, have many potential applications in synthetic chemistry and materials science, but they are very challenging to achieve. Here, the dissymmetric reaction of 1,4-dibromo-2,5-diethynylbenzene (2Br-DEB) on Ag(111) is realized by using a stepwise activation strategy, leading to an ordered two-dimensional organometallic network containing both alkynyl–silver–alkynyl and alkynyl–silver–phenyl nodes. Scanning tunneling microscopy and density functional theory calculations are employed to explore the stepwise conversion of 2Br-DEB, which starts from the H-passivation of one Br-substituted site at 300 K in accompaniment with an intermolecular reaction to form one-dimensional organometallic chains containing alkynyl–silver–alkynyl nodes. Afterwards, the other equivalent Br-substituted site undergoes metalation reaction at 320–450 K, resulting in transformation of the chains into the binodal networks. These findings exemplify the achievement of the dissymmetric reaction and its practical application for controlled fabrications of complicated yet ordered nanostructures on a surface.
Decabromodiphenyl ethane (DBDPE) is an alternative to the commercial decabromodiphenyl ether (deca-BDE) mixture but has potentially similar persistence, bioaccumulation potential and toxicity. While it is widely used as a flame retardant in electrical and electronic equipment (EEE) in China, DBDPE could be distributed globally on a large scale with the international trade of EEE emanating from China. Here, we performed a dynamic substance flow analysis to estimate the time-dependent mass flows, stocks and emissions of DBDPE in China, and the global spread of DBDPE originating in China through the international trade of EEE and e-waste. Our analysis indicates that, between 2006 and 2016, ∼230 thousand tonnes (kt) of DBDPE were produced in China; production, use and disposal activities led to the release of 196 tonnes of DBDPE to the environment. By the end of 2016, ∼152 kt of the DBDPE produced resided in in-use products across China. During the period 2000–2016, ∼39 kt of DBDPE were exported from China in EEE products, most of which (>50%) ended up in North America. Based on projected trends of China's DBDPE production, use and EEE exports, we predict that, by 2026, ∼74 and ∼14 kt of DBDPE originating in China will reside in in-use and waste stocks, respectively, in regions other than mainland China, which will act as long-term emission sources of DBDPE worldwide. This study discusses the considerable impact of DBDPE originating in China and distributed globally through the international trade of EEE; this is projected to occur on a large scale in the near future, which necessitates countermeasures.
This study focuses on the Danjiangkou reservoir, and investigates the release regulation of total nitrogen, nitrate, nitrite and ammonia from sediments as a function of temperature, perturbation and aeration conditions. Moreover, a simulation reactor was set up to explore the elimination of endogenous nitrogen pollution through high-efficient aerobic denitrification microorganism augmentation. Effects of high-efficient aerobic denitrification microorganisms on the microbial community structure in the sediments was also evaluated by means of high-throughput sequencing technology. The results indicated that increasing temperature could promote the release of nitrate and nitrite from sediments, while inhibiting the release of ammonium. Disturbances of water was beneficial to nitrogen release from sediments, and the nitrogen amount accumulated in the overlying water was proportional to the agitation speed. Concentrations of dissolved oxygen had great effects on the nitrogen release from sediments. It was found that the aeration treatment significantly reduced the release of total nitrogen and nitrite from sediments, and the subsequent accumulation in water. After addition of the a high-efficient aerobic denitrification bacteria Pseudomonas stutzeri (PCN-1) into the simulation reactor, concentrations of all the forms of nitrogen in the reactor increased at first and then decreased. On the 65th day of the experiment, removal rates of total nitrogen and nitrate released from sediments were as high as 75.87% and 79.96% respectively, suggesting effective control of the endogenous nitrogen. The relative abundance of Proteobacteria, Bacteroidetes and Spirochaetes in sediments was significantly increased after PCN-1 addition, so the microbial community structure in the sediments was changed by microbial augmentation treatment with PCN-1 as well.以丹江口水库为例,考察水库底泥在不同温度、扰动和曝气等条件下,总氮、硝氮、氨氮和亚硝氮的释放规律。设置模拟反应器,探究高效好氧脱氮微生物强化消除 水库底泥内源氮污染的效果,并运用高通量测序技术,分析高效好氧脱氮微生物对底泥微生物群落结构的影响。结果表明,温度升高会减少氨氮的释放,增加硝氮和 亚硝氮的积累;水体扰动会加速底泥中氮素释放,且上覆水中的氮素释放累积量与扰动速度成正比;溶解氧对底泥氮素释放有显著影响,曝气处理可以明显地降低底 泥中总氮和硝氮的释放及其在水体中的累积。在反应器中底泥-上覆水界面投加高效好氧脱氮微生物Pseudomonas stutzeri (PCN-1)后,反应器内各种形态的氮素都出现先上升、后下降的趋势;在反应器运行的第65天,底泥释放的总氮和硝氮的去除率分别高达75.87%和7 9.96%,底泥内源氮污染得到有效的控制。对比投加菌株前后的微生物群落结构,发现底泥中Proteobacteria, Bacteroidetes和Spirochaetes的相对丰度明显增加, PCN-1强化脱氮处理能够改变底泥的微生物群落结构。
We develop a non-perturbative approach for calculating the superconducting transition temperatures (\$T\_\c\\$) of liquids. The electron-electron scattering amplitude induced by electron-phonon coupling (EPC), from which the effective pairing interaction can be inferred, is related to the fluctuation of the \$T\$-matrix of electron scattering induced by ions. By applying the relation, EPC parameters can be extracted from a path-integral molecular dynamics simulation. For determining \$T\_\c\\$, the linearized Eliashberg equations are re-established in the non-perturbative context. We apply the approach to estimate \$T\_\c\\$ of metallic hydrogen liquids. It indicates that metallic hydrogen liquids in the pressure regime from \$0.5\$ to \$1.5$\backslash$mathrm\$\backslash$,TPa\\$ have \$T\_\c\\$ well above their melting temperatures, therefore are superconducting liquids.
Combined water pollution with the coexistence of heavy metals and organic contaminants is of great concern for practical wastewater treatment. In this study, a jaboticaba-like nanocomposite, titanate nanotubes supported TiO2 (TiO2/TiNTs), was synthesized by a two-step hydrothermal treatment. TiO2/TiNTs had large surface area, abundant of –ONa/H groups and fine crystal anatase phase, thus exhibited both good adsorptive performance for Cu(II) and high photocatalytic activity for phenanthrene degradation. The maximum Cu(II) adsorption capacity on TiO2/TiNTs was 115.0 mg/g at pH 5 according to Langmuir isotherm model, and >95% of phenanthrene was degraded within 4 h under UV light. TiO2/TiNTs showed about 10 times higher observed rate constant (kobs) for phenanthrene degradation compared to the unmodified TiNTs. More importantly, the coexistence of Cu(II) promoted photocatalytic degradation of phenanthrene, because the incorporated Cu(II) in the lattice of TiNTs could trap photo-excited electron and thus inhibited the electron-hole recombination. Density functional theory (DFT) calculation indicated that the sites of phenanthrene with high Fukui index (f0) preferred to be attacked by OH radicals. The quantitative structure–activity relationship (QSAR) analysis revealed that the degradation intermediates had lower acute toxicity and mutagenicity than phenanthrene. TiO2/TiNTs also owned high stability, as only slight loss of Cu(II) and phenanthrene removal efficiency was observed even after four reuse cycles. The developed material in this study is of great application potential for water or wastewater treatment with multi-contaminants, and this work can help us to better understand the mechanisms on reaction between Ti-based nanomaterials and different kinds of contaminants.
