The proportion of granular ice in sea ice layers has markedly increased due to global warming. To investigate the uniaxial compressive behavior of granular sea ice, we conducted a series of experiments using natural piled and level ice samples collected from the Bohai Sea. A total of 311 specimens were tested under controlled temperature conditions ranging from −15 °C to −2 °C and strain rates varying from 10⁻⁵ to 10⁻² s⁻¹. The effects of porosity, strain rate, and failure modes were studied. The results show that both the uniaxial compressive strength and uniaxial compressive elastic modulus were dependent on strain rate and porosity. Granular sea ice exhibited a non-monotonic strength dependence on strain rate, with the strength increasing in the ductile regime and decreasing in the brittle regime. In contrast, the elastic modulus increased monotonically with the strain rate. Both the strength and elastic modulus decreased with increasing porosity. Level ice consistently demonstrated higher strength and an elastic modulus than piled ice at equivalent porosities. Unified parametric models were developed to describe both properties across a wide range of strain rates encompassing the ductile-to-brittle (DBT) regime. The experimental results show that, as porosity decreased, the transition strain rate of granular sea ice shifted from 2.34 × 10⁻³ s⁻¹ at high porosity (45%) to 1.42 × 10⁻⁴ s⁻¹ at low porosity (10%) for level ice and 1.87 × 10⁻³ s⁻¹ to 1.19 × 10⁻³ s⁻¹ for piled ice. These results were compared with classical columnar ice models. These findings are useful for informing the design of vessel and coastal structures intended for use in ice-covered waters.

In quantum communication, the concept of dense coding traditionally relies on maximally entangled states as quantum channels. Recent advancements have expanded this framework to include non-maximally entangled states within the probabilistic dense coding paradigm. However, such schemes introduce a significant limitation: the receiver cannot always retrieve the complete dense coding information sent by the sender. Consequently, the receiver must inform the sender of the amount of information successfully received. Based on this feedback, the sender determines whether retransmission is necessary, leading to inefficient use of the quantum channel and reduced communication efficiency. To address these shortcomings, we propose an alternative deterministic quantum dense coding scheme that utilizes non-maximally entangled states as the quantum channel. This deterministic approach eliminates the need for retransmissions and significantly enhances communication efficiency while maintaining compatibility with non-maximally entangled states. Our scheme represents a substantial improvement over existing probabilistic methods and paves the way for more efficient quantum communication protocols.

Seasonal lake-ice runways provide low-carbon winter infrastructure for cold-region logistics, yet direct links between ice flexural mechanics and runway design remain scarce. To address this gap, we investigated seasonal ice from Huhenuoer Lake and proposed a mechanics-based methodology for determining key design parameters. On 14 March 2024, an ice block was hoisted and tested in a cold laboratory after several days. Full-depth investigation revealed that throughout the entire-depth range, the ice consists exclusively of columnar ice with a mean density of 0.89 g/cm³ and a mean grain size of 15.88 mm. Subsequently, four-point bending tests gave an average effective flexural elastic modulus of 3.31 GPa and flexural strength of 2813 kPa. Furthermore, statistical analysis showed both properties decrease with temperature and are lower in higher-porosity specimens. Based on these results, we established a systematic procedure to derive design flexural strength, effective flexural elastic modulus, and ice thickness. When applied to the potential Huhenuoer Lake-ice runway, this method yields values of 2800 kPa, 3.24 GPa, and 30 cm for the An-2 (design flexural strength, design effective flexural elastic modulus, and design ice thickness, respectively); the same method can be used to obtain the corresponding values for other aircraft. As lake ice is locally sourced, recyclable, and temporary, it can serve as a low-carbon material for construction purposes.