Mary Kay China: Making Chinese Women’s Lives Beautiful

The direct sales cosmetics company Mary Kay Inc. has earned its place in a man’s world by blazing a new path for women. Since opening its first factory in China in 1995, Mary Kay China has sought to introduce the values of the company’s founder in a market and culture far removed from Mary Kay Ash’s native Texas. Although the company’s direct selling model was banned by the Chinese government in 1998 and was held in suspicion by many Chinese consumers, Mary Kay China — by holding fast to its values as well as to its direct selling model — managed to establish a solid reputation and gain a significant share of the Chinese cosmetics market. Mary Kay China has also provided opportunities for thousands of women to have their own careers and has helped to redefine notions of feminine beauty among Chinese women. To accommodate ever-changing customer demands and combat fierce competition in the growing cosmetics sector, Mary Kay China must maintain its corporate philosophy within the flexible structure of direct selling. As a company that aims to “enrich women’s lives”, Mary Kay has a demanding mandate. Its values must somehow be internalized by hundreds of thousands of independent distributors/sellers with very different backgrounds. But outside the big cities, traditional Chinese culture conflicts with Mary Kay’s understanding of the role of women. Expanding into China’s second- and third-tier cities and more remote regions poses great challenges

A high-reliability SEPIC converter with reconfigurable voltage conversion gain

A high-reliability SEPIC converter with reconfigurable voltage conversion gain is proposed, which is composed of a basic SEPIC converter and n extended units. Adopting an interleaved parallel structure on the input side of the converter not only achieves leg-level hardware redundancy but also reduces the input current ripple. When one branch of the converter suddenly changes or fails, due to the redundancy between branches, the converter can still to work, and the duty cycle of the other branches can be readjusted by using PI control without changing output voltage and power of the converter. This feature undoubtedly presents the reliability of the converter. On the contrary, when the converter works in normal operation, it can also actively control operation mode of each branch to achieve reconfigurable voltage conversion gain function. In addition, since the duty cycles of the switches are not limited, voltage conversion gain of the converter is widely, which makes it more suitable for the occasions where the input side fluctuates greatly. Section 2 details the working principle of the proposed converter and the voltage and current stress on components. Then, the reconfigurable voltage conversion gain of the converter and its high reliability characteristics are analyzed in Section 3. Finally, the correctness of the theoretical analysis is verified by experiments

A Novel High Step-up Converter for Photovoltaic Systems

A bipolar high step-up Cuk-Sepic converters based on the 'coat circuit' is proposed, which can be used to connect single photovoltaic (PV) panel and inverters. The main advantage of the proposed converter is that it contains only one active switch as the same as the Cuk or Sepic converter, so it is easy to drive and control. The 'coat circuit' is introduced to increase the voltage gain of the converter and reduce the voltage stress of the devices. In addition, the proposed converter can output equalized bipolar voltage with common ground. This paper introduces the working principle and performance analysis of the proposed converter in detail. In order to verify the correctness and validity of the theoretical analysis, a 266.7W experimental prototype has been built.</p

Single-atom Sn-Zn pairs in CuO catalyst promote dimethyldichlorosilane synthesis

Single-atom catalysts are of great interest because they can maximize the atom-utilization efficiency and generate unique catalytic properties; however, much attention has been paid to single-site active components, rarely to catalyst promoters. Promoters can significantly affect the activity and selectivity of a catalyst, even at their low concentrations in catalysts. In this work, we designed and synthesized CuO catalysts with atomically dispersed co-promoters of Sn and Zn. When used as the catalyst in the Rochow reaction for the synthesis of dimethyldichlorosilane, this catalyst exhibited much-enhanced activity, selectivity and stability compared with the conventional CuO catalysts with promoters in the form of nanoparticles. Density functional theory calculations demonstrate that single-atomic Sn substitution in the CuO surface can enrich surface Cu vacancies and promote dispersion of Zn to its atomic levels. Sn and Zn single sites as the co-promoters cooperatively generate electronic interaction with the CuO support, which further facilitates the adsorption of the reactant molecules on the surface, thereby leading to the superior catalytic performance

Single-atom Sn-Zn pairs in CuO catalyst promote dimethyldichlorosilane synthesis

Single-atom catalysts are of great interest because they can maximize the atom-utilization efficiency and generate unique catalytic properties;however,much attention has been paid to single-site active components,rarely to catalyst promoters.Promoters can significantly affect the activity and selectivity of a catalyst,even at their low concentrations in catalysts.In this work,we designed and synthesized CuO catalysts with atomically dispersed co-promoters of Sn and Zn.When used as the catalyst in the Rochow reaction for the synthesis of dimethyldichlorosilane,this catalyst exhibited much-enhanced activity,selectivity and stability compared with the conventional CuO catalysts with promoters in the form of nanoparticles.Density functional theory calculations demonstrate that single-atomic Sn substitution in the CuO surface can enrich surface Cu vacancies and promote dispersion of Zn to its atomic levels.Sn and Zn single sites as the co-promoters cooperatively generate electronic interaction with the CuO support,which further facilitates the adsorption of the reactant molecules on the surface,thereby leading to the superior catalytic performance

Additive manufacturing of alloys with programmable microstructure and properties

Acknowledgements: The authors from Nanyang Technological University (NTU) and University of Cambridge would like to acknowledge M.J. Demkowicz, Z. Cordero, and M. Duchamp for valuable discussion, C. Todaro for the beamtime of neutron diffraction in ANSTO, Z. Wang and T.P. Le for technical support, and the Facilities for Analysis, Characterization, Testing and Simulations (FACTS) at NTU for access to electron microscopy equipment. This research was funded by the National Research Foundation (NRF) Singapore, under the NRF Fellowship program (NRF-NRFF2018-05). S.V.P. acknowledges support from the Swiss National Science Foundation (SNF Sinergia 193799). H.L.S. acknowledges support from the Science and Engineering Research Council, Agency for Science, Technology and Research (A*STAR), Singapore (142 68 00088). H.G. acknowledges support from Advanced Models for Additive Manufacturing (AM2) program under A*STAR (M22L2b0111) and support as a Distinguished University Professor of NTU and Scientific Director of Institute of High Performance Computing of the A*STAR, Singapore.AbstractIn metallurgy, mechanical deformation is essential to engineer the microstructure of metals and to tailor their mechanical properties. However, this practice is inapplicable to near-net-shape metal parts produced by additive manufacturing (AM), since it would irremediably compromise their carefully designed geometries. In this work, we show how to circumvent this limitation by controlling the dislocation density and thermal stability of a steel alloy produced by laser powder bed fusion (LPBF) technology. We show that by manipulating the alloy’s solidification structure, we can ‘program’ recrystallization upon heat treatment without using mechanical deformation. When employed site-specifically, our strategy enables designing and creating complex microstructure architectures that combine recrystallized and non-recrystallized regions with different microstructural features and properties. We show how this heterogeneity may be conducive to materials with superior performance compared to those with monolithic microstructure. Our work inspires the design of high-performance metal parts with artificially engineered microstructures by AM.</jats:p

Additive manufacturing of alloys with programmable microstructure and properties

Acknowledgements: The authors from Nanyang Technological University (NTU) and University of Cambridge would like to acknowledge M.J. Demkowicz, Z. Cordero, and M. Duchamp for valuable discussion, C. Todaro for the beamtime of neutron diffraction in ANSTO, Z. Wang and T.P. Le for technical support, and the Facilities for Analysis, Characterization, Testing and Simulations (FACTS) at NTU for access to electron microscopy equipment. This research was funded by the National Research Foundation (NRF) Singapore, under the NRF Fellowship program (NRF-NRFF2018-05). S.V.P. acknowledges support from the Swiss National Science Foundation (SNF Sinergia 193799). H.L.S. acknowledges support from the Science and Engineering Research Council, Agency for Science, Technology and Research (A*STAR), Singapore (142 68 00088). H.G. acknowledges support from Advanced Models for Additive Manufacturing (AM2) program under A*STAR (M22L2b0111) and support as a Distinguished University Professor of NTU and Scientific Director of Institute of High Performance Computing of the A*STAR, Singapore.In metallurgy, mechanical deformation is essential to engineer the microstructure of metals and to tailor their mechanical properties. However, this practice is inapplicable to near-net-shape metal parts produced by additive manufacturing (AM), since it would irremediably compromise their carefully designed geometries. In this work, we show how to circumvent this limitation by controlling the dislocation density and thermal stability of a steel alloy produced by laser powder bed fusion (LPBF) technology. We show that by manipulating the alloy’s solidification structure, we can ‘program’ recrystallization upon heat treatment without using mechanical deformation. When employed site-specifically, our strategy enables designing and creating complex microstructure architectures that combine recrystallized and non-recrystallized regions with different microstructural features and properties. We show how this heterogeneity may be conducive to materials with superior performance compared to those with monolithic microstructure. Our work inspires the design of high-performance metal parts with artificially engineered microstructures by AM

Additive manufacturing of alloys with programmable microstructure and properties

In metallurgy, mechanical deformation is essential to engineer the microstructure of metals and to tailor their mechanical properties. However, this practice is inapplicable to near-net-shape metal parts produced by additive manufacturing (AM), since it would irremediably compromise their carefully designed geometries. In this work, we show how to circumvent this limitation by controlling the dislocation density and thermal stability of a steel alloy produced by laser powder bed fusion (LPBF) technology. We show that by manipulating the alloy’s solidification structure, we can ‘program’ recrystallization upon heat treatment without using mechanical deformation. When employed site-specifically, our strategy enables designing and creating complex microstructure architectures that combine recrystallized and non-recrystallized regions with different microstructural features and properties. We show how this heterogeneity may be conducive to materials with superior performance compared to those with monolithic microstructure. Our work inspires the design of high-performance metal parts with artificially engineered microstructures by AM