Multi-Condition Contact Stress Analysis of High Speed Train Helical Gear

Taking traction helical gear of CRH380A high speed train for example, not only analyzing the meshing process characters of the high speed train helical gear and the tractive performance curve, but also using Pro/E to complete a three-dimensional model, combining with ANSYS workbench, helical gear contact finite element model is built in start-up, continuous and high speed conditions. A meshing period equivalent stress and contact pressure distributions of gear tooth surface are obtained by solving the model. And so are the changing regularity of gear contact state and stress on the meshing process. The result shows that based on ANSYS workbench, dynamic contact stress analysis about traction helical gear of high speed train can reflect the realistic contact stress state among the meshing process. It provides some certain references and foundations to calculate the gear’s strength analysis and modification design

Characteristics and Performance of Foreign Direct Investment in Retail Trade: The Case of Japanese Firms

In the international business development, foreign direct investment (FDI) as a general phenomenon has been extensively studied, yet the understanding of particular characteristics of FDI in the retail industry remain limited. The success of international retail trade relies heavily on the understanding of consumers in the host countries. Therefore, this paper analyzed the characteristics and performance of foreign direct investment (FDI) in retail trade using the Japanese FDI data (JFDI) from 1986-2001 as a case. We found (1) an overall trend for JFDI to move from the developed countries to developing countries; (2) a modest correlation between subsidiary size and performance; (3) in certain countries/regions, a positive and significant correlation between entry mode and performance; and (4) a focus of JFDI on the USA and the Greater-China area. The results of this paper provide important implications for countries which want the FDI in retail trade and for companies which want to invest in international retail trade

Phosphodiesterase-4 Inhibitors for the Treatment of Inflammatory Diseases

Phosphodiesterase-4 (PDE4), mainly present in immune cells, epithelial cells, and brain cells, manifests as an intracellular non-receptor enzyme that modulates inflammation and epithelial integrity. Inhibition of PDE4 is predicted to have diverse effects via the elevation of the level of cyclic adenosine monophosphate (cAMP) and the subsequent regulation of a wide array of genes and proteins. It has been identified that PDE4 is a promising therapeutic target for the treatment of diverse pulmonary, dermatological, and severe neurological diseases. Over the past decades, numerous PDE4 inhibitors have been designed and synthesized, among which roflumilast, apremilast, and crisaborole were approved for the treatment of inflammatory airway diseases, psoriatic arthritis, and atopic dermatitis, respectively. It is regrettable that the dramatic efficacies of a drug are often accompanied by adverse effects, such as nausea, emesis, and gastrointestinal reactions. However, substantial advances have been made to mitigate the adverse effects and obtain better benefit-to-risk ratio. This review highlights the dialectical role of PDE4 in drug discovery and the disquisitive details of certain PDE4 inhibitors to provide an overview of the topics that still need to be addressed in the future