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The purpose of this paper is to investigate the laser soldering of fine pitch quad flat package (QFP) devices using lead‐free solders and solder joint reliability during thermal cycling.

QFP devices were selected as the test vehicles and were soldered with four alloy types, Sn37Pb, Sn3.5Ag, Sn3.8Ag0.7Cu and Sn3.8Ag0.7Cu0.03Ce. The experimental samples were QFP‐256 devices with lead‐free solder paste on the printed circuit boards. The packages were dried for 24 h at 125°C prior to reflow soldering. Soldering experiments on the QFP devices were carried out with an infrared (IR) reflow soldering oven and a diode laser (DL) soldering system. Reflow soldering was performed at peak temperatures of 210°C (SnPb), 240°C (SnAgCu and SnAgCuCe) and 250°C (SnAg), as determined on the boards. Pull testing was adopted to evaluate the tensile strength of the four solders using an STR–1000 micro‐joint strength tester.

The tensile force of the QFP micro‐joints increased as laser intensity increased when it was less than an “optimal” value. The maximum tensile force of the QFP micro‐joints was gained when the laser intensity had increased to 2,165, 2,127, 2,165 and 2,064 W/cm², depending on the alloy used. The thermal fatigue performance of three lead‐free solder joints, SnAgCuCe, SnAgCu and SnAg, was determined to be superior to that of the eutectic SnPb alloy. After soldering without thermal cycling tests, the fracture morphology of soldered joints exhibited characteristic toughness fracture with both of the soldering methods. After 700 thermal cycles, the fracture mechanism was also toughness fracture, nevertheless, the dimples became large. The fracture morphology of the soldered joints subjected to 1,500 thermal cycles indicated brittle intergranular fracture on the fracture surface and no intense plastic deformation appeared before fracture with IR soldering. For DL soldering, the pull fracture model of the SnAgCuCe was completely ductile in the soldered joint with 1,500 thermal cycles.

The paper usefully investigates the influence of laser intensity on the tensile strength of different soldered joints and the solder joint reliability during thermal cycling.

This study aims to investigate the factors that affect the intention to use public mobile libraries and enhance the quality of mobile library services to attract and retain users.

A questionnaire survey was conducted with 391 valid users in China. Based on the stimulus–response theory and user individual characteristics, a model was developed to examine the factors influencing the intention to use public mobile libraries. The model was tested using statistical software, such as SPSS 25.0 and AMOS 24.0.

The results indicate that technological factors, content factors, individual factors and psychological factors significantly influence the intention to use public mobile libraries. The impact of system quality and perceived ease of use in technological factors is relatively balanced. Among content factors, information quality is the most significant, while information literacy has a greater influence compared to subjective norms in individual factors. In psychological factors, perceived matching and perceived pleasure both positively influence usage intention, while perceived cost has a negative impact.

Firstly, this study only investigates users’ intention to use, but intention does not necessarily equate to actual usage behaviour (King and He,2006). Future research can introduce new variables to explore users’ adoption and continuous usage behaviours. Secondly, this study does not differentiate between different types of mobile library users. Future research can consider different user types, such as potential users and current users, to investigate the similarities and differences in their willingness to adopt mobile library services. Thirdly, this study is primarily cross-sectional. Future research can consider longitudinal studies to provide more in-depth insights into user behaviour.

This paper identifies external and internal stimulus factors and conducts a comprehensive investigation into the factors influencing the intention to use public mobile libraries, thus providing generalizable research findings. Unlike previous studies, this research introduces the information literacy variable, enriching the model of factors affecting users' intention to use mobile libraries and yielding more comprehensive conclusions. Consequently, the study aims to be grounded in the actual usage ideas and intentions of diverse user groups, constructing a model that highlights factors influencing the intention to use public mobile library services.

From a social perspective, this study offers four implications for improving the utilization of public mobile libraries. Firstly, it is crucial to integrate digital resources, enhance information quality in public mobile libraries and improve platform usability. Secondly, adopting a user-oriented approach is essential to improve the service level of public mobile libraries and stimulate residents’ participation. Thirdly, efforts should be made to strengthen user information literacy and increase information utilization. Fourthly, top-level design improvements, effective promotion efforts and user behaviour guidance are essential for the success of public mobile libraries.

This study contributes to the improvement of public mobile library services and the advancement of modern public cultural services by identifying the key factors that drive the intention to use such services. The findings have practical implications for promoting high-quality development and enhancing the popularity of public mobile libraries.