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A split Hopkinson pressure bar was used to perform dynamic compression experiments on HS-Q&P steel at the strain rates of 0-12000 s-1. The deformation behavior of the specimen during dynamic compression was studied by SEM, EBSD, XRD characterization methods. The results show that the deformation behavior of the experimental steel at different rates is similar and is divided into three stages. First, there is a slight increase in stress at the platform, but the increase is more reflected in the strain. The adiabatic heating effect that occurs during the compression process will bring a softening effect. The strength and plastic deformation ability of the experimental steel can be improved by the retained austenite. The volume fraction of retained austenite in steel reduced by the transformation induced plasticity (TRIP) effect is the same as the volume fraction of martensite increased and proves the TRIP effect is the main strengthening mechanism in the steel. At the same time, it is observed by SEM that the retained austenite is transformed into acicular martensite by the TRIP effect. As the strain rate increases, the lattice distortion becomes more and more serious, and some deformation twins can be observed in the EBSD maps. At different strain rates, 〈001〉oriented grains are more likely to produce deformation twins.

Identification and understanding of persistent regional heat wave are essential for adaption and alleviation of its severe effects on human health and ecological environment, particularly under the situation of rapid global warming. Based on Climate Prediction Center global daily maximum temperature from 1979 to 2019, considering extreme, persistence and regionality of heat wave, summer regional pentad heat wave (RPHW) is defined by summer daily maximum temperature above 35°C with no less than 3 days in a pentad, which is also required to cover more than 2% grids over the eastern China. It breaks down the continuity constraints in both time and space in previous regional heat wave definitions that mainly indicate the synoptic phenomena. Besides, our RPHW is much useful in examining climatic features of regional heat wave, since it filters out the weather noises to some extend in terms of a pentad window. Three categories of RPHW are identified by K-means cluster analysis over the eastern China, i.e., North-Central China (NCC), Central China (CC), and South China (SC). Generally, intensity and area of RPHW are positively proportional to each other, and more RPHW appears in SC but with weaker intensity, whereas less RPHW locates in NCC and CC with stronger intensity. While RPHW in CC and SC mostly appears in middle-late summer, RPHW in NCC mainly occurs in early-middle summer which is transferred from the middle-late summer before the late 1990s. Most RPHW persists for one pentad and occasionally for five or six pentads at most. And both frequency and accumulated days of RPHW have been significantly increased since the late 1990s, particularly in CC and SC. Significant high-pressure anomalies are accompanied with the RPHW in China, which favor more incoming net solar radiation, increasing surface soil temperature, and more upward surface longwave radiation and sensible heat flux as well, eventually forming the RPHW. Specifically, the RPHW in NCC and SC are mainly caused by diabatic heating from the land surface and adiabatic heating due to the anomalous subsidence movement, respectively; however, both the diabatic heating and the adiabatic heating are responsible for the RPHW in CC.

The six-hourly ERA-interim reanalysis data were used to analyze the intraseasonal oscillation (ISO) characteristics of the zonal wind in the exit region of the East Asian subtropical westerly jet (EAJ) during the winter (November to April). The results indicate that from East Asia to the North Pacific, the zonal wind in the upper troposphere shows significant 10–40-day oscillations, propagating eastward toward the jet exit region. The strength of the intraseasonal zonal wind anomaly increases from the lower troposphere to the upper troposphere, reaching a peak between 300 and 200 hPa. The zonal wind ISO in the jet exit area is closely related to the intraseasonal inverse temperature tendency between the north and south of the jet exit in the troposphere. In the acceleration (deceleration) phase of the intraseasonal west wind, the air temperature decreases (increases) in the north of the exit and increases (decreases) in the south of the exit. The intraseasonal temperature tendency is stronger in the north of the EAJ exit than that in the south. In the north of the EAJ exit, the intraseasonal temperature tendency is decided by the temperature advection, where the whole troposphere is controlled by the north wind in the west wind acceleration phase and controlled by the south wind in the west wind deceleration phase, so the intensity of temperature advection is strong. However, adiabatic heating plays a decisive role in affecting the temperature evolution in the south of the jet exit area, and the intraseasonal meridional wind is the opposite between the mid-upper troposphere and the lower troposphere, resulting in weak temperature advection and the weak temperature tendency. Therefore, although the zonal wind ISO in the jet exit area is the result of the joint action of the ISOs in different latitudes, the influence of mid-high latitudes is particularly important.

We investigated the early-stage development of cyclones occurring in the strong baroclinic regions in the Northwest Pacific and the Northwest Atlantic based on European Center for Medium-range Weather Forecasts Re-Analysis-Interim (ERA-Interim) data. The composite background conditions corresponding to the cyclones on the onset day are characterized by upper troposphere divergence of westerly jet ahead of a trough, low troposphere convergence of westerly jet behind a trough, and strong meridional air temperature gradient (baroclinicity) both in the Northwest Pacific and the Northwest Atlantic, but with stronger baroclinicity in the Northwest Pacific. The composite velocity and temperature fields of the cyclone on the onset day show a clear horizontal front and a westward and northward vertical tilting of cyclonic circulation to the cold zone. The composite Northwest Pacific cyclone filed on the onset day has a warm core, whereas the composite Northwest Atlantic cyclone field has a cold core in the low troposphere. The leading adiabatic processes that contribute to the developing of the cold core cyclone in the Northwest Atlantic on the onset day is the temperature advection, while stronger vertical motion induces stronger adiabatic warming in the Northwest Pacific cyclones, which has a significant contribution to the development of warm core cyclones on the onset day.

Micro-injection moulding (µ-IM) is a fabrication method that is used to produce miniature parts on a mass production scale. This work investigates how the process parameter settings result in adiabatic heating from gas trapped and rapidly compressed within the mould cavity. The heating of the resident air can result in the diesel effect within the cavity and this can degrade the polymer part in production and lead to damage of the mould. The study uses Autodesk Moldflow to simulate the process and identify accurate boundary conditions to be used in a gas law model to generate an informed prediction of temperatures within the moulding cavity. The results are then compared to physical experiments using the same processing parameters. Findings from the study show that without venting extreme temperature conditions can be present during the filling stage of the process and that venting solutions should be considered when using µ-IM.

The present study concerns the deformation and fracture behavior of two ferrite–martensite dual phase steels (FMDP660 and FMDP780) with different phase fractions subjected to different strain rate (0.001 s−1 to 1000 s−1) tensile testing. For both steels, the yield strength (YS) monotonically increased with strain rates, whereas the values of ultimate tensile strength (UTS), uniform elongation (UE) and post-uniform elongation (PUE) were maintained stable at the low strain rate range (0.001–0.1 s−1), followed by a significant increase with strain rate at high strain rate levels (0.1–1000 s−1). The FMDP780 steel with a higher fraction of martensite possessed a stronger strain rate sensitivity of tensile strength and elongation (UE and PUE) values at the high strain rate stage, compared with the FMDP660 sample. The change of UTS and UE with different strain rates and phase fractions was highly related to the strain hardening behavior, which was controlled by the dislocation multiplication in ferrite, as validated by transmission electron microscopy (TEM). The fracture surface of the two steels was characterized by dimpled-type fracture associated with microvoid formation at the ferrite–martensite interfaces, regardless of the strain rates. The change of the dimple size and PUE value of the two steels with strain rates was attributed to the effect of adiabatic heating during tensile testing.