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The purpose of this paper is to explore the geometric parameter difference of the terrace-like structural transfer film under different working parameters [pressure and velocity (PV) values] and filled particle types (three fillers: SiO₂, TiO₂ and ZnO), and find the geometric parameter related to the wear of polytetrafluoroethylene (PTFE)-based composites.

PTFE composites were filled with SiO₂, TiO₂ and ZnO particles, and the morphology parameter of the PTFE composite transfer film under different PV values obtained from the rotary reciprocating pin-on-disk frictional tester was quantified by using a three-dimensional laser scanning microscope.

The results showed that the effective layer coverage rate and effective thickness of the transfer film had a good relationship with the wear of the three PTFE composites. On the whole, increasing the speed or load was helpful to increase the effective thickness of the three PTFE composite transfer films, but reduced the effective layer coverage rate. The greater the effective layer coverage rate and effective thickness of the transfer film, the better the wear resistance of the PTFE composites in the entire speed and load range.

This work will promote further understanding of the transfer film and lay a foundation for realizing its morphology regulation and improving the wear of the PTFE composites.

Vinyl coating systems provide an outstanding combination of properties—toughness, flexibility, abrasion resistance, adhesion, weatherability, water resistance and chemical resistance—that have enabled such coatings to have a proven record of long term performance unsurpassed by any other type of coating. Fifteen or twenty years are quite common terms of satisfactory protection, with only occasional spot touch‐ups needed; this means low maintenance costs per year of life for the protection of structural steel. Since the labour costs for adequate metal preparation, such as blast cleaning, and for applying the coatings is estimated to cover some 80% of the total cost of a job, the importance of a good, long term protection can be readily appreciated.

Over the past few years there has been increasing utilisation of higher density surface mounting on printed wiring boards. As components and pads decrease in size, the topography of the solder mask relative to the conductors becomes an important solderability issue. There exists convincing evidence that thinner, more conformal solder mask geometries improve soldering yields of both stencilled and wave soldered surface mount components. In order to provide the solder mask coverage required for improved assembly performance, the authors critically compared several commercially available solder mask coating technologies. The coating methods were appraised according to both assembly and printed wiring board manufacturing criteria. Within this programme, seven liquid photoimageable solder masks were also evaluated. The materials were rated according to their final cured properties (electrical, mechanical, chemical performance), their manufacturability in the printed wiring board manufacturing process (maximum throughput, major defects, etc.) and their performance in assembly operations (soldering yields, propensity to ‘solder ball’ formation, white residues, scratches, etc.). The information obtained was used to choose a solder mask strategy which would not only improve assembly efficiency but also increase PWB manufacturing yields and flexibility.

Aims to experimental determination of paint flow rate flux for elliptical paint sprays. Paint flow rate flux distribution is necessary for computer simulation of the spray painting process.

Different painting strokes at different spray distances and painting velocities are made on flat surfaces by using paint sprays with elliptical spray areas. Then, thickness measurements are made across the strokes after the paint dries out completely. Thickness distributions are used for determination of the paint flow rate flux distribution by making use of the developed formulation and algorithm.

Finds that it is possible to determine the paint flow rate flux for elliptical paint sprays by making use of the painting strokes made on flat surfaces at different spray distances and painting velocities.

Computer simulation of the spray painting process for elliptical paint sprays is made possible. Simulation software for circular paint sprays has been developed previously by the authors.

Paint flow rate flux distribution is necessary for computer simulation of the spray painting process. Such simulation software has been developed previously by the authors.

This paper aims to investigate how ball milling (BM) and load influence transfer film on counterbody and the correlation between transfer film and tribological properties of copper-based composites.

The copper-based mixed powders preprocessed by BM for different times were used to manufacture sintered materials. Specimens were tested by a custom pin-on-flat linear reciprocating tribometer and characterized prior and after tests by optical microscope, scanning electron microscope and energy-dispersive spectroscopy. Image J® and Taylor-hobson-6 surface roughness meter were used to quantify the coverage and thickness of the transfer film.

Main results show that an appropriate amount of BM time and applied load can contribute to the formation of the transfer film on counterbody and effectively improve the tribological properties of the copper-based material. The transfer film coverage is linearly related to the friction coefficient, thickness of transfer film and wear volume. As the transfer film coverage increases, the coefficient of friction decreases. As the thickness of the transfer film increases, the amount of wear increases.

This work intends to control and optimize the formation of transfer film, thereby helping improve the tribological properties of materials and providing a reference to guide the preparation of Cu-based composites with excellent tribological properties.

Outgassing of PTH PCBs at different stages of PCB production was studied with a modified IEC outgassing test, Draft June 1985, now included in IEC 326–2 Amendment No. 2, January 1988. Outgassing rate from single PTHs was quantitatively measured with a U‐tube manometer as a pressure of expanded steam escaped. Some technological parameters were taken into account and different comparisons were made: PCB production stage (drilling, copper and solder plating, reflowing) vs. outgassing rate, laminate thickness vs. outgassing rate. The contributions to outgassing of PTHs through PCB production, especially from copper and tin‐lead plating, are seen. On PCBs, drilled with different drills and soldered unpopulated on wave and drag soldering machines, outgassing faults were assessed. By multiple regression the relation between outgassing faults, hole wall roughness and plated copper thickness was calculated.

The purpose of this paper is to investigate the distribution and surface characteristic of transfer film of polyamide composites filled with ZnOw during traction rolling.

In this paper, the traction rolling tribological behavior of polyamide composites filled with ZnOw was studied with a twin-disc traction rolling tester. The topography of transfer film was observed with a three dimensional profiler. Meantime the thickness of transfer film was measured. The chemistry elements of transfer film were analyzed with EDS and XRD.

The results indicated that transfer film of composites patchily covered on the surface of counter disc, the amount of which increased with increasing cycles. The coverage and thickness of pure PA film increased against rolling cycles. However, the thickness of 15 wt.% ZnOw/PA film remained at 6 μm as the coverage rose against rolling cycles. Fe element was found in pure PA transfer film, which existed in Fe0 and FeO for chemical reaction between Fe and atmospheric oxygen. Transfer film of 15 wt.% ZnOw/PA composites included a little Zn and Fe element. Fe element existed as Fe0. Zn element existed as ZnO.

This paper presented the distribution and surface characteristic of transfer film during traction rolling.

Aims to introduce a self‐adjusting robotic painting process for automotive fuel containers, capable of predicting the required correction action to avoid further defect production.

Presents the development, testing and on‐site implementation of a robotic thermal machine vision system designed for evaluating coat thickness and coverage attributes. Computer simulation is used to study the effect of the painting robot's program on the film build‐up.

Effective technique for the real‐time detection of anti‐corrosive coat's pinholes and pop‐ups. A systematic study for this paint deposition scheme.

The presented detection system and the simulation program methodology could be further studied and modified for other painting applications.

Provides insights validated with on‐site results and systematic study for the automated or the manual adjustments of the robotic painting parameters.

Introduces a novel application of thermal imaging for evaluating coated surfaces. In addition, a first reported case study of automotive fuel container's painting process. Presents potential application to reduce the defects generation thus, improving quality, and reducing production cost.

This study intends to explore the relationship between digital finance and the vertical specialization of firms. The following questions are discussed: (1) As a representative new financial development model, what is the role of digital finance in the vertical specialization of firms? (2) If digital finance improves the level of vertical specialization of firms, what is the mechanism behind such improvement? (3) How does digital finance impact the vertical specialization of firms in different regions, industries, and firms?

A two-way fixed-effect model of panel data is proposed to verify the relationship between digital finance and the vertical specialization of firms. This model is constructed by matching the city-level data of digital finance with the data of China's A-share listed companies from 2011 to 2018. Meanwhile, the instrumental variable (IV) method and difference-in-difference (DID) method are adopted to deal with the endogeneity problem of the model.

The authors' study finds that digital finance has significantly improved the level of vertical specialization of firms. The result is robust under the endogeneity consideration and a series of robustness tests. After the dimensionality of the index is reduced, the depth of digital finance usage is more conducive to the improvement of the vertical specialization of firms compared with the width of digital finance coverage and the level of financial digitization. Digital finance mainly improves the level of vertical specialization of firms by reducing transaction costs and increasing the market thickness of the intermediate products. Moreover, digital finance has certain heterogeneity in promoting the vertical specialization of firms, an effect that is more significant in the eastern region, manufacturing industry and state-owned enterprises (SOEs).

The first limitation is the mechanism test. This research only analyzes the mechanism from transaction cost and the market thickness of the intermediate products. With the rapid development of information technology, digital finance will be further integrated into people's production and life. There will then be more mechanisms that should be explored between digital finance and the vertical specialization of firms. Another limitation is the data sample of this paper. The conclusions of this research are based only on the data of listed companies. However, in the authors' opinion, the specialization level of small and medium-sized enterprise (SMEs) should be higher. Therefore, the conclusions of this work are underestimated, which can be considered as the lower limit of digital finance for enterprise specialization.

As a favorable financing channel to supplement traditional financial service functions, digital finance plays a critical role in the operating efficiency of enterprises and the effective allocation of macro resources. The authors' research shows that digital finance has significantly improved the vertical specialization of firms. This conclusion provides guides to improve the production efficiency of enterprises and the quality of economic development.

This paper has three main contributions. (1) The relationship between financial development and the vertical specialization of firms is innovatively discussed from the perspective of digital finance, which implies that digital finance can effectively promote the level of vertical specialization of firms. (2) This paper provides new perspectives and ideas to reveal the impact mechanism of digital finance on the real economy by systematically analyzing the mechanism of digital finance on the vertical specialization of firms from the perspectives of transaction costs and financing constraints. (3) The regional differences in the development of digital finance, industry differences in the vertical specialization of firms and differences in the nature of enterprise property rights are all under consideration, which improves the effectiveness and pertinence of digital finance in promoting the vertical specialization of firms.

The theory is presented of the increase in damping that can be obtained when a damping compound is added to a simple structure vibrating in a bending mode. Consideration has been given to the use of ‘Aquaplas’ damping compound on a vibrating stringer‐skin combination, and it has been shown that the maximum damping ratio is obtained when the material is applied to the stringer flange over the centre 40 per cent of the pin‐ended length of the beam. A preliminary experimental investigation is described, in which damping measurements were made on a simple structural specimen treated with Aquaplas. A new method was used successfully to determine the damping ratio of a heavily damped system. The damping properties of Aquaplas were evaluated, and some of the theoretical conclusions were verified. Some of the results obtained indicate that a more accurate mathematical representation must be sought for the visco‐elastic behaviour of Aquaplas than is provided by the ‘complex stiffness’ method.