Search results

The measurement of heat flux is of importance to the development of aerospace engine as basic physical quantities in extreme environment. Heat radiation is one of the basic forms of heat transfer phenomenon. The structure optimizing can improve the performance and infrared absorptivity of the thin film sensor.

This paper designed one kind of thin film heat flux sensor (HFS) with antireflective coating based on transparent conductive oxide thermopile. The introduced membrane structure is so thin that it has little impact on sensor performance. Fabrication of thin film sensors were fabricated by physical vapor deposition (PVD) process.

The steady-state and dynamic response characteristics of the HFS were investigated by calibration platform. The experimental results shown that the absorptivity of the membrane structure (for1070nm) improved compared with that before optimization. The sensitivity of heat flux gauge was 48.56 µV/ (kW/m2) and its frequency response was determined to be about 1980 Hz.

The thin film HFS uses thermopile based on Indium Tin Oxid and In2O3. The antireflective coating is introduced to hot endpoint of HFS to improve sensitivity on laser thermal source. The infrared optical properties of membrane layer structure were investigated. The steady-state and the transient response characteristics of the heat flux sensor were also investigated.

The aim of this study is to investigate the horizontal displacement effects of foundation pit excavation on adjacent metro stations and shield tunnel composite structures. It seeks to develop a theoretical calculation method capable of accurately assessing these engineering impacts, aiming to provide practical assistance for engineering applications.

This study introduces a model for shield tunnel segments incorporating rotation and misalignment, considering the constraints of metro stations. It establishes a displacement model for tunnel-station combinations during foundation pit excavation, deriving a formula for calculating station-proximal tunnel horizontal displacements. The method's accuracy is validated against field data from three engineering cases. The research also explores variations in tunnel displacement, inter-ring shear force, misalignment and rotation angle under different spatial relationships between pits, tunnels and stations.

This study models uneven deformation between stations and tunnels due to bending stiffness and shear constraints. It enhances the misalignment model with station-induced shear effects and introduces coefficients for their mutual interaction. Results show varied responses based on pit-station-tunnel positioning: minimal displacement near pit edges (coefficients around 0.1) and significant effects near pit centers (coefficients from 0.4 to 0.5). “Whip effect” from station constraints affects tunnel displacement, shear force, misalignment and rotation, with fluctuations decreasing with distance from excavation areas.

This study demonstrates significant originality and value. It introduces a novel displacement model for tunnel-station combinations considering station constraints, addressing theoretical calculations of horizontal displacement effects from foundation pit excavation on metro stations and shield tunnel structures. Through validation with field data and parameter studies, the concept of influence coefficients is proposed, offering insights into variations in structural responses under different spatial relationships. This research provides crucial technical support and decision-making guidance for optimizing designs and facilitating practical construction in similar engineering projects.

N-containing heterocyclic benzotriazole derivatives as new corrosion inhibitor for mild steel contained in emulsion were synthesized, and their inhibition behaviors for mild steel (MS) contained in emulsion were investigated by experiments and theoretical calculations, and this study aims to prove that two new inhibitors have excellent inhibition efficiency for steel corrosion.

2-(1H-benzo[d][1,2,3]triazol-1-yl)-N,N-dioctylacetamide (BTN) and O-(3-(1H-benzo[d] [1,2,3]triazol-1-yl)propyl) S-(2-(dioctylamino)-2-oxoethyl) carbonodithioate (BTSC) as a new corrosion inhibitor were synthesized, and their inhibition behaviors for MS contained in emulsion were investigated by gravimetric experiment, electrochemical tests and theoretical calculations.

Results of gravimetric experiment, electrochemical tests show that BTSC exhibit excellent inhibition performance, and it has a higher inhibition efficiency of 96.6% than that BTN. The resultant adsorption films from BTN/BTSC adsorbed on MS, effectively inhibiting the corrosion of MS is mainly through chemisorption and follow to Langmuir’s adsorption isotherm.

Experimental and theoretical calculations display that two new synthesized inhibitors are excellent corrosion inhibitor for MS contained in emulsion. Electrons of inhibitors mainly focus on the C, N, S and O atoms, which demonstrate these atoms are the centers of negative charge, and they supply electrons to Fe atoms through coordination bonds.

The purpose of this paper is to examine the role of infrastructure on the income growth and poverty reduction of rural household in China by estimating the impact of road accessibility on the extent of household off-farm employment and its heterogeneous effects among the groups with different income level and earning capacity.

Using nationally representative panel data collected in 100 villages about 2000 households across five provinces in 2005, 2008, 2012, 2016 and 2019. This study adopts Tobit model with panel data, zero-inflated Poisson model and static nonbalanced panel model to yield consistent results.

We find that road accessibility generally has no effect on the number of off-farm laborers and duration of off-farm employment. However, road accessibility is not beneficial for the households in the low-income villages or with low educational attainment, but it benefits the households in the high-income villages by promoting local off-farm employment or with high educational attainment by increasing the duration of migrant off-farm employment.

This study identifies the heterogeneous effects of road accessibility on the extent of off-farm employment among rural households, which narrows the research gap and enriches the literature. The empirical findings imply that road accessibility widens the gap between rich and poor in off-farm employment, which is of great important to the alleviation of relative poverty after 2020 in China.

The purpose of this paper is to investigate the role of institutional investors in the cost of equity for Chinese firms, especially state-owned enterprises (SOEs).

By using data from Chinese firms with a unique state ownership structure, we provide empirical evidence on whether institutional investors can help reduce the cost of equity for SOEs and non-SOEs, respectively, and if so, identify the underlying channels.

We find that an increase in the shareholdings of institutions, especially independent institutions, can lead to a reduction in the cost of equity. This effect is particularly prominent in SOEs compared to non-SOEs. Moreover, institutional investors promote corporate social responsibility activities and innovation activities of invested firms, thereby reducing the cost of equity.

This paper contributes to a comprehensive understanding of the effects of institutional shareholdings with heterogeneity on the cost of equity and their influential mechanisms in the process of mixed ownership reform.

The purpose of this study is to find the relationships among the high- and new-technology enterprise (HNTE) identification policy, firm’s total factor productivity (TFP) and the marketization process by using data obtained from China manufacturing firms.

Propensity matching score – difference-in-difference modeling are used to investigate the relationships among the HNTE identification policy, firm’s TFP and the marketization process. In addition, the complex relations between policy and firm’s TFP, including in the proposed model, are assessed in detail through the mediation analysis.

The results show that the HNTE identification policy can promote firm’s TFP, but its effect depends on the marketization process. The transmission path of HNTE identification policy to promote enterprise productivity lies in the optimization of incentive mechanism, including the improvement of enterprise labor productivity, the reduction of income tax burden and cost and the reduction of financing constraints. In industries and regions with more effective market mechanism, as well as industries with more intense market competition, the productivity promotion effect of the HNTE identification policy is stronger. In industries and regions with low degree of marketization, as well as industries with low degree of market competition, the productivity promotion effect brought by the improvement of incentive mechanism is distorted, which actually inhibit the promotion of enterprises’ TFP.

The study confirms that the HNTE identification policy plays an important role in enhancing the TFP of China’s manufacturing firm. Policy makers can adopt industrial policy in the key industries and technology areas that are meaningful but market failure. Furthermore, it demonstrates that the effect of the HNTE identification policy largely depends on the marketization process. These finding imply that when formulating an industrial policy, the marketization process of the industry and region should be taken into account.

The paper analyzes the relationship among the HNTE identification policy, firm’s TFP and the marketization process. Panel data are used to discuss the mechanism of HNTE identification policy affecting firm’s TFP. The paper also reveals the effect of the marketization process on the effectiveness of the HNTE identification policy.

Gallic acid is a substance that is widely found in nature. Initially, it was only used as a corrosion inhibitor to retard the rate of corrosion of metals. In recent years, with intensive research by scholars, the modification of coatings containing gallic acid has become a hot topic in the field of metal protection. This study aims to summarize the various preparation methods of gallic acid and its research progress in corrosion inhibitors and coatings, as well as related studies using quantum chemical methods to assess the predicted corrosion inhibition effects and to systematically describe the prospects and current status of gallic acid applications in the field of metal corrosion inhibition and protection.

First, the various methods of preparation of gallic acid in industry are understood. Second, the corrosion inhibition principles and research progress of gallic acid as a metal corrosion inhibitor are presented. Then, the corrosion inhibition principles and research progress of gallic acid involved in the synthesis and modification of various rust conversion coatings, nano-coatings and organic resin coatings are described. After that, studies related to the evaluation and prediction of gallic acid corrosion inhibition on metals by quantum chemical methods are presented. Finally, new research ideas on gallic acid in the field of corrosion inhibition and protection of metals are summarized.

Gallic acid can be used as a corrosion inhibitor or coating in metal protection.

There is a lack of research on the synergistic improvement of gallic acid and other substances.

The specific application of gallic acid in the field of metal protection was summarized, and the future research focus was put forward.

To the best of the authors’ knowledge, this paper systematically expounds on the research progress of gallic acid in the field of metal protection for the first time and provides new ideas and directions for future research.

Through the case analysis of China’s digital library, the purpose of this paper is to make readers understand the development status, achievements and problems of China’s digital library. At the same time, it also enables readers to understand the common application forms of these modern information technologies in digital libraries, so as to provide a reference basis for the application of new technologies in other countries’ digital libraries.

On the basis of literature review, the authors have analyzed a conspicuous collection of related papers in order to make a comprehensive summary and elaboration on the present situation of modern information technology application in Chinese digital libraries.

This paper defines and analyses the concepts, contents and relationships of the three most important modern Big Data information technologies, and then completes the analysis of the current situation of the application of information technology in Chinese digital libraries. The block chain can achieve more accurate information collection, more secure information storage and more effective information dissemination. Artificial intelligence can improve the existing digital library service level in three aspects: resource construction, information organization and information service. Internet plus will help transform the traditional digital library business mode in order to adapt to the change of user-centered service.

This is among the first structured attempts of comprehensively and generally summarizing the application of modern information technology in Chinese digital libraries. It also contains an original exploration of the relationship between the main kinds of modern information technology. Based on this, a relatively complete application scenario and possible vision of modern information technology in digital library can be built.

The density peak clustering algorithm (DP) is proposed to identify cluster centers by two parameters, i.e. ρ value (local density) and δ value (the distance between a point and another point with a higher ρ value). According to the center-identifying principle of the DP, the potential cluster centers should have a higher ρ value and a higher δ value than other points. However, this principle may limit the DP from identifying some categories with multi-centers or the centers in lower-density regions. In addition, the improper assignment strategy of the DP could cause a wrong assignment result for the non-center points. This paper aims to address the aforementioned issues and improve the clustering performance of the DP.

First, to identify as many potential cluster centers as possible, the authors construct a point-domain by introducing the pinhole imaging strategy to extend the searching range of the potential cluster centers. Second, they design different novel calculation methods for calculating the domain distance, point-domain density and domain similarity. Third, they adopt domain similarity to achieve the domain merging process and optimize the final clustering results.

The experimental results on analyzing 12 synthetic data sets and 12 real-world data sets show that two-stage density peak clustering based on multi-strategy optimization (TMsDP) outperforms the DP and other state-of-the-art algorithms.

The authors propose a novel DP-based clustering method, i.e. TMsDP, and transform the relationship between points into that between domains to ultimately further optimize the clustering performance of the DP.

In this study, a novel glutathione (GSH) surface molecular imprinting polymer (SMIP) was successfully prepared by using macroporous adsorption resins (MAR) as substrate, which could separate and purify GSH efficiently.

SMIP was synthesized by chloromethylated modified MAR (LX1180-Cl) as the substrate, N, N’-methylenebisacrylamide (NMBA) as a crosslinker, GSH as a template, acrylamide (AM) and N-vinylpyrrolidone (NVP) as functional monomers. The morphology and structure of the polymer were characterized by scanning electron microscope and Fourier transforms infrared spectroscopy.

The maximum adsorption capacity toward GSH was 39.0 mg/g and the separation decree had relation to L-cysteine (L-cys) was 4.2. The optimal operation conditions were studied in detail and the got as follows: the molar ratios of NMBA, AM, GSH and NVP, were 7.0, 0.8 and 0.5. The optimal time and temperature were 14 h and 40°C, respectively. The Langmuir and pseudo-first-order model were fitting these adsorption characteristics well.

GSH has a diversity of medicinal and bioactive functions, so the purpose of this study representing a method in separate and purify technology of GSH, which provided a way for the development of medicine.

This contribution provided a novel way to separate GSH from L-cys. Under the optimal conditions, the maximum adsorption capacity toward GSH was 39.0 mg/g and the separation decree had relation to L-cys was 4.2.