Search

This study aims to employ a causal network model based on transfer entropy for the early warning of systemic risk in commodity markets. We analyzed the dynamic causal relationships of prices for 25 commodities related to China (including futures and spot prices of energy, industrial metals, precious metals, and agricultural products), validating the effect of the causal network structure among commodity markets on systemic risk. Our research results identified commodities and categories playing significant roles, revealing that industry and precious metal markets possess stronger market information transmission capabilities, with price fluctuations impacting a broader range and with greater force on other commodity markets. Under the influence of different types of crisis events, such as economic crises and the Russia–Ukraine conflict, the causal network structure among commodity markets exhibited distinct characteristics. The results of the effect of external shocks to the causal network structure of commodity markets on the entropy of systemic risk suggest that network structure indicators can warn of systemic risk. This article can assist investors and policymakers in managing systemic risk to avoid unexpected losses. [ABSTRACT FROM AUTHOR]

Based on Geely JLE-4G18TDB 1.8T gasoline engine stand and optical 3D profile measuring instrument, this paper explores the rapid carbon accumulation process and characterization about carbon deposition of nozzle in a direct injection gasoline engines. By using aging accelerators, cycle conditions and long-term fuel pulse width correction coefficient, rapid carbon accumulation close to actual road conditions is achieved. The carbon accumulation situation of the nozzle was mastered in the state of the engine without stopping, and the carbon accumulation characteristics of the nozzle were characterized by optical means. The volume data, three-dimensional image and carbon volume distribution map of the injector before and after carbon deposition were obtained under the condition that the carbon in the surface area of the injector was not destroyed, which played an important role in the evaluation of the gasoline purifier and purifier synergist.

The Euro 7 emission standards for light-duty vehicles released at the end of 2022 have for the first time restricted the emission of non exhaust particulate matter from vehicles, which has attracted widespread attention from brake and tire manufacturers and vehicle manufacturers. Prior to this, there were few reports on the testing methods for brake wear particulate matter emissions in China, and most of them focused on studying the emission characteristics and composition of brake wear particulate matter emissions. This article reviews the testing methods for particulate matter emissions from light-duty vehicle braking wear at home and abroad, including methods based on inertia dyno bench, operating loss sealed chamber, actual road and pin-on-disc tribometer.