With the increasing awareness of environmental protection, people’s concern of pollution issues arising. Vehicles, as the most important means of transportation, its exhaust emission has received considerable attenti...With the increasing awareness of environmental protection, people’s concern of pollution issues arising. Vehicles, as the most important means of transportation, its exhaust emission has received considerable attention. The catalytic converter is able to purify harmful substances in exhaust gas. The absolute content of precious metals in the catalytic converter dominates the exhaust gas purification effect. Accurate detection of precious metal content is of great significance for controlling the cost of catalysts, ensuring catalytic performance and recovering precious metals from spent catalysts. We herein summarized several instruments for precious metals content exploration, such as X-ray fluorescence spectrometer (XRF), atomic absorption spectrometer (AAS), inductively coupled plasma emission spectrometer (ICP) and spectrophotometer. In this thesis, the feasibility of using various devices for characterizing precious metal content in catalytic converters is analyzed and their strengths or weaknesses are elaborated.展开更多
This study reveals the time-varying spillover effects of higher moments(realized volatility,realized skewness and realized kurtosis)and jumps between China’s precious metals and industrial metals markets.Using 5-min ...This study reveals the time-varying spillover effects of higher moments(realized volatility,realized skewness and realized kurtosis)and jumps between China’s precious metals and industrial metals markets.Using 5-min high-frequency data from May 10,2012 to October 21,2021,the dynamic effects of spillovers are uncovered using the time-frequency domain spillover index framework.The results show that the system connectedness weakens as the moment order gets higher whereas the total jumps connectedness is the smallest,and the spillovers of all estimators are more evident in the short term.The overall information spillovers are time-varying and influenced by major market events.Specifically,for realized volatility,copper is the largest net transmitter and silver is always a net transmitter,while zinc is the largest net receiver.For realized skewness,copper is the largest net transmitter and silver is always a net transmitter,while lead is the largest net receiver.For realized kurtosis and jumps,copper is the largest net transmitter,while aluminum is the largest net receiver.Overall,copper and silver play dominant roles in China’s precious and industrial metals markets system.展开更多
The paper gives a review on the pesent situation and the development of analysis of metallic materials,including gravimetry;titrimetry;sepectrophotometry;catalytic spectrophotometry;atomic absorption spectrometry;atom...The paper gives a review on the pesent situation and the development of analysis of metallic materials,including gravimetry;titrimetry;sepectrophotometry;catalytic spectrophotometry;atomic absorption spectrometry;atomic fluorescence spectrometry;atomic emission spectrometry;inductively coupled plasma mass spectrometry;X-ray fluorenscence spectrometry;electrochemical analysis;analysis of gases in metallic materials;original position analysis;standard analytical method and reference materials;evaluation of measurement uncertainty,during the period from Jan 2006 to Dec 2007 in China.A total of 420 references arecited.展开更多
文摘With the increasing awareness of environmental protection, people’s concern of pollution issues arising. Vehicles, as the most important means of transportation, its exhaust emission has received considerable attention. The catalytic converter is able to purify harmful substances in exhaust gas. The absolute content of precious metals in the catalytic converter dominates the exhaust gas purification effect. Accurate detection of precious metal content is of great significance for controlling the cost of catalysts, ensuring catalytic performance and recovering precious metals from spent catalysts. We herein summarized several instruments for precious metals content exploration, such as X-ray fluorescence spectrometer (XRF), atomic absorption spectrometer (AAS), inductively coupled plasma emission spectrometer (ICP) and spectrophotometer. In this thesis, the feasibility of using various devices for characterizing precious metal content in catalytic converters is analyzed and their strengths or weaknesses are elaborated.
基金the financial support from the National Natural Science Foundation of China(No.72172107)。
文摘This study reveals the time-varying spillover effects of higher moments(realized volatility,realized skewness and realized kurtosis)and jumps between China’s precious metals and industrial metals markets.Using 5-min high-frequency data from May 10,2012 to October 21,2021,the dynamic effects of spillovers are uncovered using the time-frequency domain spillover index framework.The results show that the system connectedness weakens as the moment order gets higher whereas the total jumps connectedness is the smallest,and the spillovers of all estimators are more evident in the short term.The overall information spillovers are time-varying and influenced by major market events.Specifically,for realized volatility,copper is the largest net transmitter and silver is always a net transmitter,while zinc is the largest net receiver.For realized skewness,copper is the largest net transmitter and silver is always a net transmitter,while lead is the largest net receiver.For realized kurtosis and jumps,copper is the largest net transmitter,while aluminum is the largest net receiver.Overall,copper and silver play dominant roles in China’s precious and industrial metals markets system.
文摘The paper gives a review on the pesent situation and the development of analysis of metallic materials,including gravimetry;titrimetry;sepectrophotometry;catalytic spectrophotometry;atomic absorption spectrometry;atomic fluorescence spectrometry;atomic emission spectrometry;inductively coupled plasma mass spectrometry;X-ray fluorenscence spectrometry;electrochemical analysis;analysis of gases in metallic materials;original position analysis;standard analytical method and reference materials;evaluation of measurement uncertainty,during the period from Jan 2006 to Dec 2007 in China.A total of 420 references arecited.
