Aging and Sintered Layer Defect Detection of Discrete MOSFETs Using Frequency Domain Reflectometry Associated With Parasitic Resistance

Metal-oxide-semiconductor field-effect transistors (MOSFETs) undergo fatigue degradation under high thermal and electrical stresses. This process results in changes in their parasitic parameters, which can be detected using frequency domain reflectometry (FDR). Frequency domain impedance analysis is employed to characterize the various...

BI-IEnKF coupling model for effective source term estimation of natural gas leakage in urban utility tunnels

As an effective way to facilitate the increasing demand for reliable infrastructure, energy supply and sustainable urban development, underground utility tunnels have been developed rapidly in recent years. Due to the widespread distribution of utility tunnels, the safe operation of natural gas pipelines accommodated in utility tunnels has...

The change in temporal trend and spatial distribution of CO₂ emissions of China's public and commercial buildings

The CO₂ emission mitigation of the commercial and public building sector (P&C) is critical for achieving China's carbon peak and carbon neutrality. Analyzing changes in CO₂ emissions and their driving factors from temporal and spatial perspective provides insights for developing equitable and effective...

Influence of coarse aggregate settlement induced by vibration on long-term chloride transport in concrete: a numerical study

High-frequency vibration helps to improve the compactness of concrete, but also causes the settlement of coarse aggregates (CAs) and then affects the durability of hardened concrete. In this paper, a numerical study combining multi-phase CA settlement model and multi-component ionic transport model is performed to understand the influence of...

Numerical analysis of multi-factors effects on the leakage and gas diffusion of gas drainage pipeline in underground coal mines

Gas drainage system is a critical technique to prevent gas outbursts in the underground coal mine. The leakage of gas drainage pipelines can pose serious threats to the safety production of underground mining. In this paper, a multi-factors gas drainage pipeline leakage and diffusion (GDPLD) model is proposed based on the OpenFOAM platform,...

An experimental and numerical investigation of coarse aggregate settlement in fresh concrete under vibration

Fresh concrete needs vibration to compact, fill the mould and reach a dense state. During the compaction process, coarse aggregates (CAs) tend to settle, affecting the homogeneity and eventually the long-term durability of hardened concrete. In this study, a 3-D, multi-phase numerical model for fresh concrete is developed for better...

Urban pluvial flooding prediction by machine learning approaches – a case study of Shenzhen city, China

Urban pluvial flooding is a threatening natural hazard in urban areas all over the world, especially in recent years given its increasing frequency of occurrence. In order to prevent flood occurrence and mitigate the subsequent aftermath, urban water managers aim to predict precipitation characteristics, including peak intensity, arrival time...

Seasonal behaviour of tidal damping and residual water level slope in the Yangtze River estuary: Identifying the critical position and river discharge for maximum tidal damping

As a tide propagates into the estuary, river discharge affects tidal damping, primarily via a friction term, attenuating tidal motion by increasing the quadratic velocity in the numerator, while reducing the effective friction by increasing the water depth in the denominator. For the first time, we demonstrate a third effect of river discharge...

The effects of graphene stacking on the performance of methane sensor: A first-principles study on the adsorption, band gap and doping of graphene

The effects of graphene stacking are investigated by comparing the results of methane adsorption energy, electronic performance, and the doping feasibility of five dopants (i.e., B, N, Al, Si, and P) via first-principles theory. Both zigzag and armchair graphenes are considered. It is found that the zigzag graphene with Bernal stacking has...

Microstructure and hardness of SAC305 and SAC305-0.3Ni solder on Cu, high temperature treated Cu, and graphene-coated Cu substrates

In this study, SAC305 and SAC305-0.3Ni solder balls were soldered onto Cu, high temperature treated Cu (H-Cu) and graphene coated Cu (G-Cu) substrates, respectively. The microstructure, the interfacial reaction, and the hardness of the solder joints were investigated. The interfacial intermetallic compound (IMC) is Cu₆Sn<sub>5</sub...

Identification of driving factors for green building development in China

Green building (GB) has been actively promoted in many countries, but it has not become the mainstream in Chinese construction industry due to various reasons. This paper aims to investigate the major driving factors for the development of GB with reference of the Chinese construction market. Twenty-one factors influencing the development of...