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Seeks to present the detailed empirical study of contemporary business fluctuations in Korea. Follows the methodology of modern business cycle research in conducting an atheoretical statistical analysis of the cyclical properties of key aggregate time series. Shows, by analysis, that many of the cyclical regularities documented for developed countries also exist in Korean business cycles. Regularities include the relative volatilities of many expenditure components and the co‐movement of real and nominal variables with output. Particularly of note is the counter‐cyclicality of prices. Posits that counter‐cyclicality of prices signals the importance of supply side shocks in Korean business fluctuations. Reveals, in the analysis, that the fluctuation in the import price of oil may have been the major source of Korean business cycles. States that analysis has also revealed that there are some idiosyncrasies in Korean business cycles. Net exports are significantly pro‐cyclical and lead the cycle for most of the period under study.

This paper aims to explore the preparation and tribological performance of MoS₂ nanoparticles supported on fly ash (FA) microparticles.

FA was activated by NaOH, oleic acid and HCl to obtain three modified FA samples. Nano-MoS₂ was deposited on them to form MoS₂/FA additives for poly-α-olefin (PAO) modification. Tribological tests were conducted on a reciprocating rig through the ball-on-disk friction manner. Using X-ray diffraction, scanning electron microscope, energy dispersive spectrometer, Raman spectrometer and element analyzers, the products and their lubrication mechanisms were characterized.

At 1.5 Wt.%, nano-MoS₂ and MoS2/FA could remarkably improve the tribological properties of PAO. The nano-MoS₂ deposited on the HCl-activated FA presented better lubrication performance than nano-MoS₂. It could reduce friction and wear by approximately 27% and approximately 66%, respectively. The lubrication of MoS₂/FA can be attributed to the formation of MoS₂ and carbon containing lubricating film.

FA was applied as a supporter to prepare MoS₂/FA lubricants. The reuse of FA, a solid waste, is important for environmental protection. Moreover, MoS₂/FA is more economical than nano-MoS₂ as a lubricant, because it contains approximately 71% of low-cost FA.

This study aims to investigate the catalytic performance and tribological properties of MoS₂ powder.

In this work, the authors attempted to use MoS₂ nanoparticles (nano-MoS₂) as a catalyst to synthesize trimethylolpropane oleate (TMPTO) by esterification of trimethylolpropane and oleic acid. The small amount of highly dispersed nano-MoS₂ catalyst remaining in TMPTO needed not to be separated and could be used as a lubricant modifier directly to achieve the purpose of improving the lubricity performance of TMPTO.

The results demonstrated that nano-MoS₂ had good catalytic esterification ability and achieved in situ dispersion of about 0.191% nano-MoS₂ in TMPTO while catalyzing the synthesis of base oil. After high-speed centrifugal sedimentation treatment, the product TMPTO still retained about 0.008% of nano-MoS₂. The above-synthesized TMPTO has significantly better lubricity performance than commercially available TMPTO, in which the friction coefficient and wear rate could be reduced by 75%.

The results of this study provide an idea for the design of catalysts for ester oil synthesis.