Can the digital economy development achieve the effect of pollution reduction? Evidence from Chinese Cities.

As a new economic form, the digital economy is not only empowering new impetus to economic growth, but also reshaping specific business forms of economical operation. Therefore, we conducted an empirical test to verify the impact and mechanism of pollution reduction in the digital economy, based on the panel data of 280 prefecture-level cities in China from 2011 to 2019. The results show that, first the development of the digital economy indeed has the positive effect of realizing pollution reduction. The results of mediating effect test indicate the influence mechanism mainly rely on promoting the upgrading of industrial structure (structural effect) and upgrading the level of green technology innovation (technical effect). Second, the results of regional heterogeneity analysis show that the emission reduction effect of digital economy development on four pollutants is characterized by weakness in the east and strong in the west in regional distribution. Third, the development of digital economy has a threshold effect on the level of economic development to achieve its pollution reduction effect. Further identification of the threshold effect indicates that the higher the level of economic development, the better in emission reduction effect.

Experimental Investigation and Thermodynamic Verification for the Phase Relation around the ε-Mg23 (Al, Zn)30 Intermetallic Compound in the Mg-Zn-Al System.

The appearance of the ε phase during the welding process can severely weaken the welding strength of dissimilar metals of Mg-Zn-Al alloy systems. An understanding of the accurate phase diagram, especially the equilibrium phase relation around the ε phase, is thus of particular importance. However, the phase interrelation near the ε-Mg23(Al, Zn)30 phase has not yet been fully studied. In this work, the local phase diagrams of the ε phase and its surrounding phases in the Mg-Zn-Al system are systematically determined by experimental investigation and thermodynamic verification. Five Mg-Zn-Al alloys and one diffusion couple were fabricated and analyzed to get accurate phase constituents and relationships adjacent to ε phase. The current experimental data obtained from Scanning Electron Microscope (SEM), X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC), and Electron Probe Micro Analysis (EPMA) were further compared with the thermodynamically computed phase relations around ε phase for verification, showing good agreements. Several important conclusions are drawn based on current experimental work, which can provide supporting information for the follow-up studies on ε phase in the Mg-Zn-Al alloy systems.

Effect of Different Isothermal Time on Microstructure and Mechanical Property of the Low-Carbon Steel Treated by Dual-Stable C-Mn Partitioning Process.

The stability of retained austenite was improved by the dual-stable C-Mn partitioning process. The phase transformation and element diffusion of dual-stable C-Mn partitioning process of tested steel were investigated by means of EPMA, SEM, OM, tensile testing machine, and other analysis methods. The effects of the first and second austenite stabilization time on the microstructure and mechanical properties of low-C-Si-Mn steel were studied, respectively. The enrichment of C and Mn elements is obvious after the dual-stable C-Mn partitioning process, and the microstructure of the tested steel is constituted of martensite, ferrite, and retained austenite. Compared with the conventional Q&P steel, the tensile strength of the steel treated by the dual-stable C-Mn partitioning process is slightly lower, but the plasticity is improved significantly. The tensile strength is 875-910 MPa, the elongation is 20-24%, and the product of strength and elongation can reach 21 GPa·%.

Investigation of Diospyros Kaki L.f husk extracts as corrosion inhibitors and bactericide in oil field.

BACKGROUND: Hydrochloric acid is used in oil-well acidizing commonly for improving the crude oil production of the low-permeable reservoirs, while it is a great challenge for the metal instruments involved in the acidification. Developing natural products as oilfield chemicals is a straight way to find less expensive, green and eco-friendly materials. The great plant resources in Qin-ling and Ba-shan Mountain Area of Shannxi Province enable the investigating of new green oil field chemicals. Diospyros Kaki L.f (persimmon), a famous fruit tree is widely planted in Qin-ling and Ba-shan Mountain Area of Shaanxi Province. It has been found that the crude persimmon extracts are complex mixtures containing vitamins, p-coumaric acid, gallic acid, catechin, flavonoids, carotenoids and condensed tannin and so on, which indicates the extracts of persimmon husk suitable to be used as green and eco-friendly corrosion inhibitors. FINDINGS: Extracts of persimmon husk were investigated, by using weight loss and potentiodynamic polarisation techniques, as green and eco-friendly corrosion inhibitors of Q235A steel in 1M HCl. The inhibition efficiency of the extracts varied with extract concentration from 10 to 1,000 mg/L. There are some synergistic effects between the extracts and KI, KSCN and HMTA. Potentiodynamic polarization studies indicate that extracts are mixed-type inhibitors. Besides, the extracts were screened for antibacterial activity against oil field microorganisms, and they showed good to moderate activity against SRB, IB and TGB. CONCLUSIONS: The inhibition efficiency of the extracts varied with extract concentration from 10 to 1,000 mg/L, and the highest reaches to 65.1% with the con concentration of 1,000 mg/L WE. KI, KSCN and HMTA they can enhance the IE of WE effectively to 97.3% at most, but not effective for KI and KSCN to AE. Tafel polarisation measurements indicate the extracts behave as mixed type inhibitor. Investigation of the antibacterial activity against oil field microorganism showed the extracts can inhibit SRB, IB and TGB with moderate to highly efficiency under 1,000 mg/L, which makes extracts potential to be used as bifunctional oil field chemicals.

Investigation of ginkgo biloba leave extracts as corrosion and Oil field microorganism inhibitors.

Ginkgo biloba (Ginkgoaceae), originating from China, now distributes all over the world. Wide application of Ginkgo biloba extracts is determined by the main active substances, flavonoids and terpenoids, which indicates its extracts suitable to be used as an effective corrosion inhibitor. The extracts of Ginkgo biloba leave have been investigated on the corrosion inhibition of Q235A steel with weight loss and potentiodynamic polarisation techniques. The inhibition efficiency of the extracts varies with extract concentration. The extracts inhibit corrosion mainly by adsorption mechanism. Potentiodynamic polarisation studies show that extracts are mixed type inhibitors. The antibacterial activity of the extracts against oil field microorganism (SRB, IB and TGB) was also investigated.

New bactericide derived from Isatin for treating oilfield reinjection water.

Isatin, an extract from Strobilanthes cusia (Nees) Kuntze, was the base for synthesizing derivatives that were screened for antibacterial activity against oilfield water-borne bacteria. The bacterial groups are sulfate reducing, iron and total. The derivatives were characterized by spectrums and they showed good to moderate activity against sulfate reducing bacteria.

Asymmetric synthesis of (+)-pyrido[3,4-b]homotropane.

(+)-pyrido[3,4- b]homotropane (PHT) was efficiently constructed in 12 steps from N, N-diisopropylisonicotinamide. The synthesis features (i) RCM reaction in installing the homotropane skeleton, (ii) Snieckus ortho-lithiation of N, N-diisopropylisonicotinamide followed by acylation, (iii) Myer reduction of bulky tertiary amide to alcohol with LiBH 3NH 2, and (iv) utilization of L-glutamic acid to introduce and establish the requisite stereogenic centers.

A fast assembly of pentacyclic benz[f]indolo[2,3-a]quinolizidine core by tandem intermolecular formal aza-[3 + 3] cycloaddition/Pictet-Spengler cyclization: a formal synthesis of (+/-)-tangutorine.

We have described a concise construction of the pentacyclic benz[f]indolo[2,3-a]quinolizidine intermediate 3 (with an overall yield of 54% for three steps), featuring a tandem intermolecular formal aza-[3 + 3] cycloaddition/Pictet-Spengler cyclization. The present work can be considered as a formal synthesis of beta-carboline alkaloid (+/-)-tangutorine. Our strategy disclosed herein constitutes a new effective general synthetic approach toward the indoloquinolizidine family of alkaloids.