Xiuqi Wang, Fenglian Sun, Bangyao Han, Yilun Cao, Jinyang Du, Long Shao and Guohuai Liu
The purpose of this paper is to investigate the wetting behaviors of Sn-5Sb-CuNiAg solders on copper substrates in different soldering processes and the effects of alloying…
Abstract
Purpose
The purpose of this paper is to investigate the wetting behaviors of Sn-5Sb-CuNiAg solders on copper substrates in different soldering processes and the effects of alloying elements on the wettability.
Design/methodology/approach
Sn-5Sb-CuNiAg solder balls (750 µm in diameter) were spread and wetted on 40 × 40 × 1 mm copper plates, in different fluxes, soldering temperatures and time. The contact angles were obtained by a home-made measuring instrument. The samples were polished and deep etched before analyzed by scanning electron microscopy. Energy dispersive X-ray spectroscopy was used to identify the composition of the joints.
Findings
The effects of different soldering processes and alloying elements on the wetting behaviors of Sn-5Sb-CuNiAg solders on copper substrates were calculated and expounded. The rosin-based flux could effectively remove oxidation layers and improve the wettability of Sn-5Sb-CuNiAg solders. Then with the increase of soldering temperature and time, the contact angles decreased gradually. The soldering processes suited for Sn-5Sb-CuNiAg solders were RMA218, 280°C and 30 s. Considered the effects of alloying elements, the wettability of Sn-5Sb-0.5Cu-0.1Ni-0.5Ag was relatively favorable on copper substrates. Besides, Ni could accumulate at the solder/Cu interface and form a jagged (Cu,Ni)6Sn5 IMC.
Originality/value
This work was carried out with our handmade experiment equipment and the production of the quinary lead-free solder alloy used in wetting tests belongs to us. The investigated Sn-5Sb-CuNiAg alloys exhibited higher melting point and preferable wettability, that was one of the candidates for high-temperature lead-free solders to replace high-Pb solders, and applied extremely to high temperature and frequency working environments of the third-generation semiconductors components, with a greater potential research and development value.
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Le Tao, Yun Su and Xiuqi Fang
The intended nationally determined contributions (INDCs) is a major outcome of the Paris Agreement on international cooperation to reduce emissions, and is likely to be the future…
Abstract
Purpose
The intended nationally determined contributions (INDCs) is a major outcome of the Paris Agreement on international cooperation to reduce emissions, and is likely to be the future scenario for carbon emissions. This paper aims to obtain the fine spatial pattern of carbon emissions in 2030, identify hot spots and analyze changes of carbon emissions with a spatial grid method.
Design/methodology/approach
Based on the integrated quantified INDCs of each economy in 2030, the authors predict the population density pattern in 2030 by using the statistics of current population density, natural growth rates and differences in population growth resulting from urbanization within countries. Then the authors regard population density as a comprehensive socioeconomic indicator for the top-bottom allocation of the INDC data to a 0.1° × 0.1° grid. Then, the grid spatial pattern of carbon emissions in 2030 is compared with that in 2016.
Findings
Under the unconditional and conditional scenarios, the global carbon emission grid values in 2030 will be within [0, 59,200.911] ktCO2 and [0, 51,800.942] ktCO2, respectively; eastern China, northern India, Western Europe and North America will continue to be the major emitters; grid carbon emissions will increase in most parts of the world compared to 2016, especially in densely populated areas.
Originality/value
While many studies have explored the overall global carbon emissions or warming under the INDC scenario, attention to spatial details is also required to help us make better emissions attributions and policy decisions from the perspective of the grid unit rather than the administrative unit.
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Lixia Wang, Xin Zhang, Beibei Yan and Vigdis Boasson
This paper aims to examine the internal logical relationship between two intergenerational inheritance ways of passing property rights and residual control rights (RCR) and to…
Abstract
Purpose
This paper aims to examine the internal logical relationship between two intergenerational inheritance ways of passing property rights and residual control rights (RCR) and to construct a conceptual model comprising transfer elements, paths and timing of succession in this process.
Design/methodology/approach
Driven by the cases of Haixin, Tianyijiao and Changhe Group, this paper applies research methods of copying and expanding analysis logic, progressive deduction, content analysis and comparative research based on the perspective of HeXie theory to explore the deep interrelation of transfer elements, paths and timing during family business succession.
Findings
The findings present that the content of intergenerational inheritance of a family firm is the inheritance of property rights and RCR. First, the inheritance of property rights is a static inheritance of time-point delivery, whereas the inheritance of RCR is a dynamic inheritance process for a period of time. Second, the inheritance of property rights and RCR are not independent; only a “HeXie” succession of both rights can realize a successful inheritance of family firms.
Originality/value
This paper constructs the paths and timing model of intergenerational inheritance of property rights and RCR in family firms. This paper integrates the current literature studies on the family inheritance of property rights and RCR and explains their internal mechanisms. This paper also provides a theoretical foundation and empirical evidence for family business transitions in the business world.