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The purpose of this paper is to discuss the possibility of using soldering process for the bonding of chip-on-flexible (COF) light-emitting diode (LED) packages to heat sinks. The common bonding materials are thermal conductive adhesives. For thermal performance and reliability concerns, Tin-Bismuth (SnBi) lead-free solder paste was used for the connection of the COF packages and the Cu heat sinks by a soldering process in this study. Meanwhile, the geometrical effect of the SnBi solder layer on the thermal performance was also investigated.

The effects of the bonding materials and the area of the solder layers on the thermal performance of the LED modules were investigated by finite element simulation and experimental tests.

The SnBi soldered modules show much lower thermal resistance at the bonding layers than the adhesive-bonded LED module. Vertical heat transfer from the LED chips to the heat sinks is the primary heat dissipation mode for the SnBi soldered modules. Thus, the LED module with local solder layer shows similar LED thermal performance with the full-area soldered module. Meanwhile, the local soldering process decreases the possibility to form randomly distributed defects such as the large area voids and residue flux in the solder layers.

The research is still in progress. Further studies mainly focus on the reliability of the samples with different bonding materials.

COF package is a new structure for LED packages. This study provides a comparison between SnBi solder and adhesive material on the thermal performance of the LED. Meanwhile, the authors optimized the geometrical design for the solder layer. The study provides a feasible bonding process for COF packages onto heat sinks.

This study provides a soldering process for the COF LED packages. The thermal performance of the LED light source was improved significantly by the new process.

A surface‐mount in‐line light emitting diode (LED) array was developed for mounting an LED dot matrix display on a single‐sided insulated metal substrate (IMS). This LED array has heat dissipating cathode leads and an anode lead that works as a jumper wire. Good heat dissipation of the LED array was obtained on an aluminium IMS.

This study investigates the impact of three parameters such as: number of LED chips, pitch and LED power on the junction temperature of LEDs using a best heat sink configuration selected according to a lower temperature. This study provides valuable insights into how to design LED arrays with lower junction temperatures.

To determine the best configuration of a heat sink, a numerical study was conducted in Comsol Multiphysics on 10 different configurations. The configuration with the lowest junction temperature was selected for further analysis. The number of LED chips, pitch and LED power were then varied to determine the optimal configuration for this heat sink. A general equation for the average LED temperature as a function of these three factors was derived using Minitab software.

Among 10 configurations of the rectangular heat sink, we deduce that the best configuration corresponds to the first design having 1 mm of width, 0.5 mm of height and 45 mm of length. The average temperature for this design is 50.5 C. For the power of LED equal to 50 W–200 W, the average temperature of this LED drops when the number of LED chips reduces and the pitch size decreases. Indeed, the best array-LED corresponds to 64 LED chips and a pitch size of 0.5 mm. In addition, a generalization equation for average temperature is determined as a function of the number of LED chips, pitch and power of LED which are key factors for reducing the Junction temperature.

The study is original in its focus on three factors that have not been studied together in previous research. A numerical simulation method is used to investigate the impact of the three factors, which is more accurate and reliable than experimental methods. The study considers a wide range of values for the three factors, which allows for a more comprehensive understanding of their impact. It derives a general equation for the average temperature of the LED, which can be used to design LED arrays with desired junction temperatures.

Given that women around the world face more exclusion in terms of limited access to economic and innovation activities than men do, it is understandable that some female-led start-ups in weak institutional environments engage in bribery to help reduce the difficulties they encounter in the face of intense business competition. However, the link between bribery and product innovation performance is unclear. The purpose of this study is to investigate the relationship between bribery and product innovation performance for female-led start-ups, as well as the roles of institutional support and self-control in this link.

This empirical study evaluates survey data from female-led manufacturing start-ups in China's Yangtze River Delta region to investigate the relationship between bribery and product innovation performance.

This research shows that bribery has an inverted U-shaped impact on product innovation performance in female-led manufacturing start-ups, meaning that the product innovation performance of these firms initially increases but then decreases as the bribery intensity (i.e. the frequency and amount of bribes) increases. The authors also focus on the roles of institutional support and self-control in this link, where the authors find that this relationship is steeper for firms with strong institutional support, as well as for individual female entrepreneurs who have high levels of self-control.

The findings of this study indicate that policymakers should undertake efforts to improve institutional quality (e.g. increasing clarity around decisions, providing more institutional support, etc.) and to guide female entrepreneurs to cultivate higher levels of self-control, as such efforts would reduce the appeal of, and the opportunity for, bribery.

To date, very few studies focus specifically on female-led enterprises in the field of bribery research. The research findings presented here on the effect of bribery in female-led start-ups on firm product innovation performance are useful to researchers, policymakers and businesspeople, as they provide a better understanding of bribery in female-led start-ups in China, which can also be extrapolated to encompass other transition economy contexts.

Implementing peer-to-peer learning models within an academic library environment presents several benefits and challenges. This study explores the effectiveness of integrating peer-assisted learning in research services and considers the impact on those providing support and those seeking assistance. A more comprehensive understanding of peer education approaches in research support services will benefit academic libraries interested in incorporating this model.

This article showcases case study data from the reference and instruction peer-led learning programs at California State University Fullerton's Pollak Library, incorporating library interns and student assistants trained to provide front line research support to fellow students from 2019 to 2022. Feedback was collected across the learning experience from student facilitators, patrons assisted and participating library supervisors.

Project data demonstrates that incorporating students in traditional academic library research services nurtures experiential learning and serves as an effective high-impact practice. Additionally, peer-led programs contribute to a helpful, welcoming atmosphere for library users and help connect libraries to the communities they serve.

Exploring survey data and student reflections, this combined study highlights advantages and implications of incorporating peer learning programs in research services in both formal and informal instruction environments. Results also reveal promising methods for recruitment, training and sustainable program development for libraries considering this approach.

Poverty is endemic in rural Nigeria and gender disparity in access to productive resources is a major cause of poverty in the area. Poverty status of rural households along gender line was, therefore, investigated in this study.

Panel data from 2010/2011 (wave 1) and 2015/2016 (wave 3) of the Living Standard Measurement Survey (LSMS) for Nigeria were used for the study. Data were analysed using Foster, Greer and Thorbecke (FGT) poverty indices and binomial panel logistic model.

Poverty measures for women-led households in farming activities were 58.5, 27.8 and 17.1%; men-led farming households had 59.8, 27.4 and 16.3% gender-neutral had 56.8%, 27 and 16.9% in the first panel. Poverty indices increased in the women-led and men-led farming households in the second panel. Poverty incidence was higher amongst farming households than the non-farming counterparts. Correlates of poverty status differ amongst the gender-groups were household size, farming, tertiary education, access to credit and geographical locations.

Gender disparity is perceived in this study along the line of differences in gender composition of rural households. A gender-blind approach to poverty alleviation programmes likely will not enhance reduced poverty in rural Nigeria. Closing the gender poverty gap will ensure achievement of the first sustainable development goal of poverty eradication.

Against the theoretical backdrop of the embeddedness and the resilience literatures, this paper investigates if and how SMEs' planning for adversity affects firms' performance.

The paper develops hypotheses that investigate the link between the risk management of immigrant-led and native-led SMEs and their performance and draw on novel data from a survey on 900 immigrant- and 2,416 native-led SMEs in 5 European cities to test them.

Immigrant-led SMEs are less likely to implement an adversity plan, especially when they are in an enclave sector. However, adversity planning is important to enhance the growth of immigrant-led businesses, even outside a crisis period, and it reduces the performance gap vis-à-vis native-led businesses. Inversely, the positive association between adversity planning and growth in the sample of native entrepreneurs is mainly driven by entrepreneurs who have experienced a severe crisis in the past.

This paper empirically uses planning for adversity as an anticipation stage of organizational resilience and tests it in the context of immigrant and native-led SMEs. Results support the theoretical reasoning that regularly scanning for threats and seeking information beyond the local community equips immigrant-led SMEs with a broader structural network which translates into new organizational capabilities. Furthermore, results contribute to the process-based view of resilience demonstrating that regularly planning for adversity builds a firm's resilience potential, though the effect is contingent on the nationality of the leaders.

Polymer-based thermal interface materials (TIMs) are having pump out problem and could be resolved for reliable application. Solid-based interface materials have been suggested and reported. The purpose of this paper is suggesting thin film-based TIM to sustain the light-emiting diode (LED) performance and electronic device miniaturization.

Consequently, ZnO thin film at various thicknesses was prepared by chemical vapour deposition (CVD) method and tested their thermal behaviour using thermal transient analysis as solid TIM for high-power LED.

Low value in total thermal resistance (R_th-tot) was observed for ZnO thin film boundary condition than bare Al boundary condition. The measured interface (ZnO thin film) resistance {(R_th-bhs) thermal resistance of the interface layer (thin film) placed between metal core printed circuit board (MCPCB) board and Al substrates} was nearly equal to Ag paste boundary condition and showed low values for ZnO film prepared at 30 min process time measured at 700 mA. The T_J value of LED mounted on ZnO thin film (prepared at 30 min.) coated Al substrates was measured to be 74.8°C. High value in junction temperature difference (ΔT_J) of about 4.7°C was noticed with 30 min processed ZnO thin film when compared with Al boundary condition. Low correlated colour temperature and high luminous flux values of tested LED were also observed with ZnO thin film boundary condition (processed at 30 min) compared with both Al substrate and Ag paste boundary condition.

Overall, 30 min CVD processed ZnO thin film would be an alternative for commercial TIM to achieve efficient thermal management. This will increase the life span of the LED as the proposed material decreases the T_J values.

Light emitting diode (LED) has been the best resource for commercial and industrial lighting applications. However, thermal management in high power LEDs is a major challenge in which the thermal resistance (R_th) and rise in junction temperature (T_J) are critical parameters. The purpose of this work is to evaluate the R_th and T_j of the LED attached with the modified heat transfer area of the heatsink to improve thermal management.

This paper deals with the design of metal substrate for heatsink applications where the surface area of the heatsink is modified. Numerical simulation on heat distribution proved the influence of the design aspects and surface area of heatsink.

T_J was low for outward step design when compared to flat heatsink design (ΔT ∼ 38°C) because of increase in surface area from 1,550 mm² (flat) to 3,076 mm² (outward step). On comparison with inward step geometry, the T_J value was low for outward step configuration (ΔT_J ∼ 6.6°C), which is because of efficient heat transfer mechanism with outward step design. The observed results showed that outward step design performs well for LED testing by reducing both R_th and T_J for different driving currents.

This work is authors’ own design and also has the originality for the targeted application. To the best of the authors’ knowledge, the proposed design has not been tried before in the electronic or LED applications.