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Thermosetting polyurethanes have excellent elastic properties and solvent resistance, but they cannot be reshaped like thermoplastic polymers after molding. In this study, we designed a thermosetting polyurethane based on a reversible reaction between isocyanates and phenolic hydroxyls instead of alcoholic hydroxyls. The phenolic urethane partially decomposed above 120 °C, but the phenolic hydroxyl and isocyanate groups reconnected upon cooling. These reversible urethane bonds contributed to the thermal self-repair of the thermosetting polyurethane network. This thermosetting elastomer was organic-insoluble below 120 °C. Compared to the original material, the healed thermoset preserved approximately 70% of its tensile strength and exhibited 86% elongation at break. This thermosetting polyurethane can be applied in self-healing coatings or adhesives. We designed a thermosetting polyurethane based on the reversible reaction between isocyanates and phenolic hydroxyls instead of alcoholic hydroxyls. The phenolic urethane partially decomposed at above 120 °C, but the phenolic hydroxyl and isocyanate reconnected upon cooling. This reversible urethane bond contributed to the thermal self-repair of the thermosetting polyurethane network and can be applied into self-healing coatings or adhesives.

Taishan Mountain in the eastern China is a normal-fault-controlled range that formed during the Meso-Cenozoic, in response to large-scale extension and lithospheric thinning of the North China Craton. However, constraints on the timing of the polyphase extensional events which formed the Taishan edifice remain poorly resolved, hindering a detailed understanding of the landscape evolution of this prominent mountain. Here, we conducted apatite (U-Th)/He dating on sixteen samples from three profiles perpendicular in the Taishan Mountain, with a major view to control structures in Taishan Mountain and to resolve the Meso-Cenozoic landscape evolution. The newly determined apatite (U-Th)/He ages show a wide variation range of ∼113 to 30 Ma, indicating a slow and protracted cooling history. The inverse thermal history modeling results reveal two pulses of enhanced cooling at ∼80 to 60 and 55 to 50 Ma, which we interpret as exhumation related to normal fault activity. Furthermore, one-dimensional modeling indicates that the magnitude of tectonic exhumation is constrained at ≥15 m/Myr across the Yunbuqiao, Zhongtianmen, and Taishan Piedmont faults. Integrating this study and published studies, we suggest that Taishan Mountain underwent four-stage evolution since 100 Ma: (1) the whole Taishan Mountain commenced a continuous and slow exhumation under a weaker tensional environment at ∼100 to 80 Ma, (2) the joint growth and interactions within a normal fault system resulted in rapid uplift and promoted the formation of the Proto-Taishan Mountain at ∼80 to 60 Ma, (3) the Taishan Mountain underwent exhumation at ∼55 to 50 Ma, interpreted as a tectonic response to the Taishan Piedmont Fault, and (4) the last stage (∼50 to 0 Ma), the Taishan Mountain experienced protracted exhumation related to normal faulting until now. We attribute the extensive normal faulting to the subduction and slab rollback of the Izanagi-Pacific Plates, which shaped the present-day geomorphology of Taishan Mountain.

Reversible data hiding in encrypted domain (RDH-ED) addresses data security and privacy protection issues. However, traditional RDH-ED algorithms face challenges in terms of dynamic authorization, multiparty collaboration, and secure sharing in distributed environments. To address these issues, this study proposes a certificateless and verifiable broadcast proxy re-encryption (CVBPRE) algorithm and introduces a proxy re-encryption-based reversible data hiding in encrypted domain (PRE-RDHED) algorithm. The CVBPRE algorithm combines broadcast proxy re-encryption (BPRE) with polynomial operations, thereby eliminating reliance on bilinear pairings to achieve efficient identity security verification. The PRE-RDHED algorithm employs proxy re-encryption (PRE) to store re-encrypted ciphertext fragments across multiple proxy nodes, thereby enabling fine-grained data access control and dynamic identity verification to ensure secure and efficient data sharing and collaboration in distributed environments. The experimental results demonstrate that the proposed algorithms satisfy indistinguishability under an adaptive chosen ciphertext attack (IND-CCA2) in the random oracle model and outperform existing schemes in terms of efficiency, security and capacity. The integration of PRE and RDH-ED enables information hiding in re-encrypted ciphertexts, facilitating secure and flexible data sharing across distributed environments.

Purpose The aim of this study was to develop and validate a nomogram to assist physicians making further decisions on the requirement of a radical surgery for T1 colorectal cancer (CRC) after local excision through preoperative prediction of lymph node metastasis (LNM). Methods A total of 141 T1 CRC patients were enrolled from January 2013 to August 2020. The independent predictive parameters were determined in multivariate analyses. The nomogram was constructed based on predictors of LNM and its performance was evaluated with respect to its calibration, discrimination, and decision curve analysis. Internal validation by bootstrapping was performed to verify the applicability of the nomogram. Results cN in CT/MRI (N+), histologic type (poorly differentiated, mucinous adenocarcinoma, and signet-ring cell carcinoma), tumor budding (G3), and lymphovascular invasion were identified in the multivariable analysis ( p <0.05). The developed nomogram incorporated these four predictors and it yielded good discrimination and calibration, with an area under the curve (AUC) of 0.89 (95% confidence interval [CI]: 0.80–0.97). However, the Japanese guideline yielded an AUC of 0.75 (95% CI: 0.63–0.87). A decision curve analysis showed that the predictive scoring system had a high clinical application value, and the nomogram conferred a greater benefit than the Japanese guideline did (range of threshold within 10%–80%). Conclusions This study proposed a novel predictive model to assist physicians in making treatment decisions regarding additional surgery after local excision.

Zirconium (Zr) is a strategic metal resource whose performance is significantly degraded by high oxygen content. The external gettering process is an effective approach for in-depth deoxidation of Zr. In this study, the deoxidation behavior of Zr in the Ca-Y-CaCl external gettering system was investigated by adjusting the chlorine potential through YCl addition. The change of oxygen potential and its synergistic control mechanism during the variation of chlorine potential were systematically examined. The results demonstrated that with increasing chlorine potential, the system undergoes a sequence of reactions: chlorination of Ca, formation of metallic Y, formation of YOCl, dissolution of Y O , and formation of YCl , ultimately reaching a three-phase equilibrium of Y-YOCl-YCl . During this process, the oxygen content of Zr fluctuates notably, which is primarily attributed to the shift in the oxygen-transfer medium from Ca to Y. This transition changes the oxygen potential control mechanism from indirect Y-Ca control to direct Y control. After reaching equilibrium at 1173 K for 72 h, the equilibrium oxygen content of Zr initially remains stable with increasing chlorine potential, then gradually decreases, eventually reaching 20 ppmw. This trend is consistent with the mutual interaction of oxygen potential and chlorine potential. The findings provide important theoretical insights into the interaction between oxygen and chlorine potentials in deoxidation systems, elucidate the multi-element synergistic mechanism for oxygen control, and contribute to the design of efficient deoxidation systems.

This paper explores covert broadcast communication in a challenging situation in which the transmitter, Alice, faces uncertainty regarding the position of the passive adversary, Willie. In this situation, controlling the signal exposure becomes difficult. Specifically, this paper focuses on the cases where Alice can delimit the suspicious areas where Willie may be located. The suspicious areas can have arbitrary number and shapes. Under the Rician fading model, the analytical expression of Willie’s detection performance is derived. Then, the transmit power, the beamforming direction, and the number of channel uses are jointly designed to minimize the optimal Willie’s detection performance among all the possible positions of Willie, on the premise of satisfying receivers’ quality-of-service requirements. To tackle the formulated knotty problem with an infinite number of irregular and discontinuous Willie’s possible positions, the continuous nature of the antenna pattern is exploited to convert the original problem into the one with a finite number of possible positions, by sampling the suspicious areas. Then, different algorithms are developed to address the resultant non-convex optimization problem for single-antenna Willie and multi-antenna Willie, respectively. Numerical results demonstrate significant performance gains of the proposed scheme over the widely-adopted maximum ratio transmission scheme, which indicates that simply adjusting the main lobe towards the receiver is indeed far away from optimum and shows the importance of leveraging Alice’s limited knowledge of Willie’s position.

Natural electric field frequency selection method was proposed by Chinese scholars in the 1980s on the basis of imitating the field observation method of the magnetotelluric method (MT). It can only measure the magnetotelluric field components of one or several frequencies on the surface to determine the existence of underground geological bodies. This method has played an important role in shallow groundwater exploration. This paper mainly discusses the application of frequency selection method in the exploration of underground hot water in the Maoyanhe Scenic spot, Zhangjiajie City, Hunan Province, in order to illustrate the effectiveness of the frequency selection method in water exploration. According to the situation of the construction site, nearly 20 geophysical prospecting survey lines of varying lengths were laid flexibly within the red line of the Maoyan River Scenic Spot. Firstly, three-frequency (170 Hz, 67 Hz and 25 Hz) measurements were carried out on each survey line to preliminarily determine the possible horizontal location of underground hot water. Secondly, in the vicinity of the low potential anomaly of the three-frequency curve, the fine measurement by using multi-frequency bipolar profile method was further carried out. The specific distribution of underground hot water was determined based on the principle of frequency domain sounding and the static effect characteristics of the electromagnetic method so as to provide a scientific basis for the drilling layout. Finally, the reliability of the frequency selection method is verified by two verification boreholes. The results indicate that the frequency selection method is one of the effective geophysical exploration methods in groundwater exploration.

Polyols with different number of hydroxyl groups were synthesized from ricinoleic acid and oleic acid. These plant oil derived polyols can be used as plasticizers and combined with ethyl cellulose (EC) through supramolecular system to prepare ethyl cellulose composite films. The morphology, thermal stability and mechanical properties of the prepared ethyl cellulose films were studied in detail to indicate the plasticizing efficiency of these polyols and the effect of the number of hydroxyl groups in polyols on EC composite film’s properties. With the addition of polyols, the tensile strength of EC composite films decreased, while the elongation at break increased. The elongation at break of EC composite films can be improved by 11–12 times when the polyols contain 1–3 hydroxyl groups. Thus, the plant oil derived polyols with 1–3 hydroxyl groups can be used as plasticizers for EC films. In addition, molecular dynamic simulations were performed to further probe the effects of the number of hydroxyl groups in polyols on EC composite film’s properties.Graphic abstract

Bulk metallic glasses (BMGs), classified as metastable materials, necessitate melt quenching at critical cooling rates higher than 102 K/s to kinetically bypass crystalline phase formation during solidification. Owing to this rapid quenching, the microstructure of BMGs can be regarded as melt quenched. This study examines how their melt state governs the thermal stability, structural characteristics, and plasticity behavior of Zr50Cu40Al10 BMG. Rod samples were prepared via injection casting at controlled melt temperatures and suction casting. Experimental observations demonstrated a positive correlation between elevated melt temperatures and enhanced glass forming ability (GFA) along with improved thermal stability (T-A) in BMGs during processing. Structural analyses confirmed the glassy nature of the prepared BMGs with different melt states and revealed their temperature-dependent atomic-scale heterogeneity: the samples quenched at low melt temperatures exhibited significant Cu-rich clustering as determined via energy-dispersive X-ray spectroscopy (EDS) mapping, and those at high melt temperatures formed homogeneous structures. This structure heterogeneity was directly correlated with good plastic deformation behavior, i.e., the rod sample prepared at the lowest melt temperature achieved 9.7% plastic strain. The transition is attributed to liquid-liquid phase transition (LLPT): below the LLPT threshold, metastable Cu-rich clusters persist in the melt and are retained upon quenching, creating structural defects that facilitate shear band multiplication. These findings highlight melt temperature as a crucial factor in tailoring the structure characteristic and mechanical behavior of Zr50Cu40Al10 BMGs.

Biobased lipoic acid (LA) can be used as a plasticizer and combine with ethyl cellulose (EC) to form ethyl cellulose supramolecular composite films. The morphology, hydrophilic performance, thermal stability and mechanical properties of the composite films were investigated. The introduction of LA can significantly improve the flexibility and processability of ethyl cellulose films because LA can weaken both hydrogen bonding and hydrophobic interaction in EC chains. The elongation at break of EC composite films can be increased by 5.5~11.1 times when the LA content is 20~50%. In addition, comparative experiments and molecular dynamic simulations were performed to explain the superiority of LA as a plasticizer for EC films.Graphic abstract