A Study of the Worle Bank's “Paying Taxes” Indicator System

李成，厦门大学管理学院教授，经济学博士；施文泼，中国财政科学研究院副研究员，经济学博士。【中文摘要】纳税营商环境是营商环境体系的重要方面之一，是一个国家或者区域内企业生产经营过程中导致纳税遵从成本的各种税收制度的集中反映。世界银行所构建的纳税营商环境指标 体系是全世界普遍公认的客观评价标准之一，但在实践中也有局限性。该纳税营商环境指标体系所涉及的指标关注于纳税申报系统的优化、申报流程以及税制的简化、企业实际税收负担、退税事项以及税收争议处理，但未能关注到税收优惠、时间成本、各国国'清差异、中介市场发展程度、企业家自身素质差异等。同时，在世行的纳税评价指标体系下，各个指标对纳税排名的敏感性存在显著差异。当前我国正处于“减税降费改革”的关键时期，就纳税营商环境所面临的主要矛盾，可采取提升企业主税收意识、建立标准操作纳税时间模型、界定纳税服务半径以及创建具有国际话语权的评价体系等措施全面优化我国的纳税营商环境。 【Abstract】As one of the most important indicators of the ease of doing business，the “paying taxes” indicator aims at reflecting all types of tax systems that lead to tax compliance costs in the process of production and operation of enterprises in a country or region. The “paying taxes” indicator established by the World Bank is one of the generally accepted and objective evaluation criteria in the world，but it has limitations in practice. On the basis of comprehensive introduction and evaluation of this indicator，this paper puts forward some ideas to deal with the World Bank's assessment of the taxation business environment，and presents some concrete recommendations for optimizing the taxation business environment in China against the background of cutting taxes and administrative fees in China.国家自然科学基金面上项目“税收政策不确定性、企业税收风险控制与税收战略选择”（71772156

Investigation of Losartan Potassium as an eco-friendly corrosion inhibitor for copper in 0.5 M H2SO4

Losartan Potassium (LP) is a commonly used drug for the treatment of hypertension. In this study, the corrosion inhibition performance of LP on copper in 0.5 M H2SO4 was investigated using electrochemicalmethods, surface morphological observation, X-ray photoelectron spectroscopy (XPS), quantum chemical calculation and molecular dynamics (MD) simulation. The electrochemical results show that LP is a type of mixed-type inhibitor that suppresses both cathode and anode reactions by forming a protective film. This film follows the Langmuir adsorption model and mainly depends on chemisorption in this process. XPS analysis confirmed that the adsorption film was due to the formation of coordination compounds between N atoms in the LP molecule and copper. Quantum chemical calculation further confirmed the active centres of N atoms in LP molecules, andMD simulation demonstrated that the inhibitor was adsorbed almost tightly and parallel to the Cu (111) surface. (C) 2020 Elsevier B.V. All rights reserved

Electrochemical Micro-Immunosensor of Cubic AuPt Dendritic Nanocrystals/Ti₃C₂-MXenes for Exosomes Detection

Exosomes are extracellular vesicles that exist in body circulation as intercellular message transmitters. Although the potential of tumor-derived exosomes for non-invasive cancer diagnosis is promising, the rapid detection and effective capture of exosomes remains challenging. Herein, a portable electrochemical aptasensor of cubic AuPt dendritic nanocrystals (AuPt DNs)/Ti3C2 assisted in signal amplification, and aptamer CD63 modified graphene oxide (GO) was immobilized on a screen-printed carbon electrode (SPCE) as the substrate materials for the direct capture and detection of colorectal carcinoma exosomes. Cubic AuPt DNs/Ti3C2 was synthesized according to a simple hydrothermal procedure, and the AuPt DNs/Ti3C2-Apt hybrid demonstrated an efficient recognition of exosomes. Under optimal conditions, a detection limit of down to 20 exosomes µL−1 was achieved with the linear range from 100 exosomes μL−1 to 5.0 × 105 exosomes μL−1. The proposed immunosensor could be suitable for the analysis of exosomes and has clinical value in the early diagnosis of cancer

Insights into the inhibition mechanism of three 5-phenyltetrazole derivatives for copper corrosion in sulfuric acid medium via experimental and DFT methods

Insights into the inhibition mechanism of three 5-phenyltetrazole derivatives for copper corrosion in sulfuric acid medium via experimental and DFT method

Experimental and theoretical studies on the inhibition properties of three diphenyl disulfide derivatives on copper corrosion in acid medium

2,2'-Dithiosalicylic acid (DSA), 2-aminophenyl disulfide (APD) and 2,2-dibenzamidodiphenyl disulfide (DPD) were determined for corrosion inhibition of Cu in H2SO4 media by electrochemical tests, surface morphology analysis, quantum chemical calculations and molecular dynamics simulations. The results of polarization curves showed that DSA, APD and DPD reveal good anti-corrosion capacity. They can simultaneously inhibit the cathodic and anodic reactions of copper. Therefore, they belong to the mixed-type corrosion inhibitors. Impedance spectroscopy results showed that when DSA, APD and DPD adsorption on the surface of Cu, the charge transfer resistance increases significantly and typical capacitance behavior produced, which indicates that the formed inhibitor film is very dense and ordered. In addition, the adsorption of corrosion inhibitors on the Cu surface is conforming to Langmuir monolayer adsorption. The experimental results obtained by surface topography analysis are consistent with the results of electrochemical experiments. Their corrosion inhibition ability is DSA < APD < DPD. Theoretical calculations further explore the relationship between corrosion inhibition performance and their molecular configurations. (C) 2019 Elsevier B.V. All rights reserved

Experimental and Theoretical Study on the Corrosion Inhibition of Mild Steel by 1‑Octyl-3-methylimidazolium l‑Prolinate in Sulfuric Acid Solution

A newly amino acid ionic liquid, 1-octyl-3-methylimidazolium l-prolinate ([Omim]­Lpro), was investigated as the inhibitor for mild steel in 0.5 M H₂SO₄ solution using weight loss method, electrochemical measurements, scanning electron microscopy (SEM), and quantum chemical calculation. The obtained results revealed that [Omim]­Lpro was a mixed-type inhibitor with a predominantly cathodic action for mild steel in 0.5 M H₂SO₄ solution, and inhibition efficiency reached nearly 80% at the concentration of 10 mM, in which the Omim cation played a major role in the corrosion inhibition of [Omim]­Lpro. The adsorption of [Omim]­Lpro on the mild steel surface was found to obey the El-Awady thermodynamic-kinetic model and Flory–Huggins isotherm equations; thus the thermodynamic and kinetic parameters governing the adsorption process were calculated and discussed. Moreover, quantum chemical calculation gave further insight into the mechanism of inhibition of [Omim]­Lpro

Mn3O4/Co(OH)(2) cactus-type nanoarrays for high-energy-density asymmetric supercapacitors

Mn3O4/Co(OH)(2) cactus-type nanoarrays for high-energy-density asymmetric supercapacitor

Mechanism of N₂O Formation during the Low-Temperature Selective Catalytic Reduction of NO with NH₃ over Mn–Fe Spinel

The mechanism of N₂O formation during the low-temperature selective catalytic reduction reaction (SCR) over Mn–Fe spinel was studied. The <i>in situ</i> diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and transient reaction studies demonstrated that the Eley–Rideal mechanism (i.e., the reaction of adsorbed NH₃ species with gaseous NO) and the Langmuir–Hinshelwood mechanism (i.e., the reaction of adsorbed NH₃ species with adsorbed NO_<i>x</i> species) both contributed to N₂O formation. However, N₂O selectivity of NO reduction over Mn–Fe spinel through the Langmuir–Hinshelwood mechanism was much less than that through the Eley–Rideal mechanism. The ratio of NO reduction over Mn–Fe spinel through the Langmuir–Hinshelwood mechanism remarkably increased; therefore, N₂O selectivity of NO reduction over Mn–Fe spinel decreased with the decrease of the gas hourly space velocity (GHSV). As the gaseous NH₃ concentration increased, N₂O selectivity of NO reduction over Mn–Fe spinel increased because of the promotion of NO reduction through the Eley–Rideal mechanism. Meanwhile, N₂O selectivity of NO reduction over Mn–Fe spinel decreased with the increase of the gaseous NO concentration because the formation of NH on Mn–Fe spinel was restrained. Therefore, N₂O selectivity of NO reduction over Mn–Fe spinel was related to the GHSV and concentrations of reactants