High-resolution 2D acoustic profiles, combined with time slices from a 3D data volume, were used to investigate the paleoincised valleys offshore of the present-day Pahang River, South China Sea. Paleovalleys were formed during the regressive phase of the last glacial cycle. They were submerged and possibly filled during valley formation and postglacial marine transgression. Interpretation of acoustic profiles illustrates that the valleys were incised and infilled during the regression and low stand followed by subsequent deglacial sea-level rise. They were overlain by a transgressive ravinement surface suggesting transitional deposits between fluvial-dominated filling and shallow-marine deposition. This ravinement surface is overlain by Holocene shallow marine deposits. A low-sinuosity low-stand valley system changed to a high-sinuosity meander belt and eventually evolved into a deltaic distributary channel system before the complete submergence of the area. The average Late Pleistocene surface lies between 53 and 64 m below present-day mean sea level in the study area with approximately 16–50 m of valley incision. The Holocene shallow marine cover thickness varies from 5 to 10 m.

Architecture and morphology of the paleo-incised valleys in Penyu Basin, South China Sea (SCS) was investigated using high-resolution two-dimensional (2D) acoustic profiles. Acoustic surveys were conducted in 2009 using a CHIRP sub-bottom profiler. The paleo-valleys were formed during several phases of regression and subsequent Last Glacial Maximum (LGM) when the sea level was approximately 123 ± 2 m lower than present-day mean sea level (MSL). These valleys were filled during lowstand and subsequent postglacial marine transgression and subsequently submerged during last glacial cycle. Holocene shallow-marine cover healed the ravinement surface. Three distinct facies and two bounding surfaces are categorized in the CHIRP profiles. Lithified pre-glacial deposits (Unit-III) are characterized by possible previous highstand deposit and regressive shoreface deposits. The erosional surface is demarcated as lowstand sequence boundary that overlain by transgressive fluvial deposits. Several stages of the incision and infilling are identified, possibly caused by fluctuating sea level transgression. The average late-Pleistocene (LGM) surface lies between 53 to 64 m below present-day MSL in the study area with ~ 16 to 50 m of valley incision. The valley slope varies 35 to 85° correspondent with the horizontal horizon. The Holocene shallow-marine cover thickness varies from 3 to 10 m.

It is extremely dangerous for a turbocharged boiler to have a leakage fault in its vaporization tube. However, early detection and fault diagnosis of micro-leakage faults are very difficult. On the one hand, there are few fault samples that lead to a difficult and intelligent diagnosis. On the other hand, the system fault response characteristics of the characterization parameters in the process are complex and easily confused with the load-changing characteristics. In order to obtain fault samples and identify fault characteristics, a fault simulation model for the micro-leakage of the boiler evaporation tube is established based on the dynamic mathematical model of all working conditions. The model’s effectiveness is verified by typical fault experiments. The dynamic simulation experiments of three kinds of micro-leakage and four kinds of load changing were carried out. Through the analysis of combustion equilibrium and vapor-liquid equilibrium of 14 groups of characterization parameters, it is found that: (1) The reason for the poor discriminability in micro-leakage faults is that most of the characterization parameters tend to balance after 300 s and the dynamic response characteristics are similar to those of load increase. (2) There are four highly distinguishable parameters: the speed of the turbocharger unit, the air supply flow, the flue gas temperature at the superheater outlet, and the furnace pressure. When the micro-leakage fault is triggered, the first three parameters have a large disturbance. They show a trend of decreasing first and then increasing in short periods, unlike normal load-changing conditions. The fourth parameter (furnace pressure) rises abnormally fast after failure. (3) Under the normal working condition of varying loads, the main common parameters take 300 s to stabilize; the common stability parameter values should be recorded because when the micro-leakage fault of evaporation occurs, the steady-state increment of failure is larger than the normal steady increment under variable load conditions, by 2 to 3 times. (4) As the leakage fault increases, the disturbance amplitude of the characteristic parameters becomes larger. In addition, the stability of the steam system becomes worse, and fault discrimination becomes more obvious.