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Using Φ1.80mm steel wire drawn from Φ6.5mm steel wire was drawn to Φ1.80mm as raw material. Using cold three-rolling process, we got flat wire which size was 0.75mm x 3.17mm by cold three-pass rolling process. Researches shown that 60 steel wire has good plastic deformation ability during cold work processing. The tensile strength and micro-hardness shows linear growth characteristics in the early first stage of cold rolling, then they have exponential growth characteristics in later rollings. That is because in the first rolling process the cementite eventually dissolved in large quantities as the ferrite is turned, deformed, refined and broken. The solution mechanism of cementite is the Gibbs-Thomson effect, i. e. interface energy mechanism.

Canopy height greatly affects the biomass stock, carbon dynamics, and maintenance of biodiversity in forests. Previous research reported that the maximum forest canopy height (Hmax) at global and regional scales could be explained by variations in water or energy availability, that is, the water- or energy-related hypothesis. However, fundamental gaps remain in our understanding of how different drivers (i.e., water and energy) contribute to the Hmax at the local scale. In this study, we selected eight dynamic forest plots (20–30 ha) across a latitudinal gradient (from 21.6° N to 48.1° N) in China and measured the canopy structure using airborne light detection and ranging (LiDAR) data. Based on the LiDAR point cloud data, we extracted the maximum tree height (Hmax) in a 20 × 20 m quadrat as a proxy for canopy height, and the topographic wetness index (TWI) and digital terrain model-derived insolation (DTMI) were calculated as proxies for water and energy conditions. We used a linear mixed model and spatial simultaneous autoregressive error model to quantify how TWI and DTMI contributed to variations in Hmax at the local scale. We found that the positive effect of TWI was stronger in subtropical and tropical forests, highlighting that water was the main factor that drives the canopy height pattern in these regions. In contrast, although the effects of DTMI can be both positive and negative, its relative contribution was higher in temperate forest plots than in other forest types, supporting the idea that energy input is more critical for Hmax in temperate forests. Overall, our study revealed the directional change from energy to water limitation from temperate to subtropical and tropical forests. Our findings can offer important insights into forest management, especially under global climate change in the Anthropocene.