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It remains enormous challenges to balance the conflict between high strength and toughness mechanical properties and excellent room‐temperature self‐healing abilities of polyurethane elastomers. In this work, we report a recyclable room‐temperature self‐healing polyurethane elastomer with excellent mechanical properties. The prepared polyurethane elastomer (PU‐DA‐Zn0.50) exhibits high tensile strength of 15.33 MPa, high toughness of 76.77 MJ m−3, and high elongation at break of 1604.46% by introducing isophorone diamine (IPDA), 1‐(3‐aminopropyl) imidazole (IMZ) and zinc ions into polymer system to form a dynamic double‐cross‐linked structure (hydrogen bonds and Zn2+‐imidazole coordination bonds). In addition, the tensile strength of fractured polyurethane can reach more than 80% of the original sample after 48 h of self‐healing at room temperature without external stimuli, which is attributed to the kinetics of rapid exchange of Zn2+‐imidazole coordination bonds at room temperature. It is worth noting that the balance between excellent mechanical properties and outstanding room‐temperature self‐healing ability can be optimized by adjusting the Zn2+‐imidazole coordination bond density in the system. Moreover, the dynamic nature of the double‐cross‐linking network endows polyurethane with favorable recyclability. The above remarkable comprehensive performances reveal a great potential of PU‐DA‐Znx elastomer in the fields of wearable flexible electronic devices such as bionic skin, human motion monitoring, and soft robots. [ABSTRACT FROM AUTHOR]

Physical unclonable function (PUF) is attractive in modern encryption technologies. Addressing the disadvantage of slow data storage/authentication in optical PUF is paramount for practical applications but remains an on‐going challenge. Here, a highly efficient PUF strategy based on random structural color domains (SCDs) of cellulose nanocrystal (CNC) is proposed for the first time, combing with hyperspectral imaging system (HIS) for ultrafast storage and authentication. By controlling the growth and fusion behavior of the tactoids of CNC, the SCDs display an irregular and random distribution of colors, shapes, sizes, and reflectance spectra, which grant unique and inherent fingerprint‐like characteristics that are non‐duplicated. Based on images and spectra, these fingerprint features are used to develop two sets of PUF key generation methods, which can be respectively authenticated at the user‐end and the manufacturer‐front‐end that achieving a high coding capacity of at least 22304. Notably, the use of HIS greatly shortens the time of key reading and generation (≈5 s for recording, 0.5–0.7 s for authentication). This new optical PUF labels can not only solve slow data storage and complicated authentication in optical PUF, but also impulse the development of CNC in industrial applications by reducing color uniformity requirement. [ABSTRACT FROM AUTHOR]

Acrylate had developed rapidly because of its excellent chemical resistance, high‐gloss surface, and weather resistance. However, the poor heat resistance of acrylate limited its application in coatings. To overcome this problem, an organic–inorganic hybrid polymer of zirconium silicone resin (ZSR)‐modified acrylate has been successfully synthesized by solution polymerization. The results indicated that the heat resistance of acrylate was significantly improved due to the SiOSi and SiOZr structures of ZSR and the increased cross‐linking density induced by ZSR. After the incorporation of ZSR, the decomposition temperatures of 5% of acrylate increased from 300.4 and 349.2°C. The performance of the ZSR/(P(MMA/BA)) showed no significant change in uniformly heating at 200°C for 24 h. The composite films showed hydrophobicity, with the contact angles increasing to more than 90°. The S4 sample displayed the outstanding comprehensive performance, that is, 5% weight loss at 341.3°C, water contact angle of 97.9°, elongation at break of 852%, and tensile strength of 9.9 MPa. The high‐performance heat resistant coating is a promising material for application in architecture, decoration, and mechanical equipment. [ABSTRACT FROM AUTHOR]

Based on the irresistible inherent trade‐off between the mechanical and self‐healing performances of cross‐linked polyurethane materials, there is still an intractable challenge to design efficient self‐healing and tough elastomers, especially in flexible sensors. Herein, a tough, efficient self‐healing, and recyclable cross‐linked polyurethane elastomer (DTPU) was prepared by integrating oxime‐carbamate bonds and thiourethane bonds into the network. The extraordinary mechanical properties and self‐healing performances of DTPU elastomers were related to the synergistic effect of oxime‐carbamate bonds in the main chain and thiourethane bonds in the chemical cross‐linked sites. The existence of dynamic cross‐linked points not only optimized the mechanical properties of DTPU but also provided support for the reversible cleavage and formation of oxime carbamate bond, thus endowing DTPU with efficient self‐healing performance and recyclability. After self‐healing at mild temperatures for 6 h, the self‐healed DTPU elastomers had a tensile strength of 30.27 MPa and a self‐healing efficiency of 95.5%. After multiple hot‐pressing, the original mechanical strength of DTPU was restored to over 100%, exhibiting excellent recyclable characteristics. Additionally, strain sensors based on self‐healing flexible elastomers were fabricated by introducing conductive carbon nanotubes. The strain sensors maintained their electrical conductivity after 3 times self‐healing, demonstrating great potential in healable flexible electronics. [ABSTRACT FROM AUTHOR]

Southeastern China (SE China) is located in the Pacific tectonic domain and has experienced a series of tectonomagmatic events induced by the subduction of the Paleo‐Pacific Plate since the late Mesozoic. The subduction formed a series of NE‐NNE oriented faults under a NW–SE regional stress field, along which a number of thermal springs occur. Previous studies have focused on the genesis mechanism of specific geothermal fields in SE China, but the general characteristics of hydrothermal systems in SE China remains unclear. In this study, we investigate the correlation between geothermal activity, hydrochemical type and regional faults by studying the distribution of hydrothermal activity and geochemical properties of typical hydrothermal systems in SE China. The hydrothermal systems in SE China have a crustal thermally‐dominated structural origin unique to the specific geological and tectonic conditions of the Eurasian Plate margin. The upwelling of the asthenosphere and the widespread granitoids with high radiogenic heat production in SE China provide major heat sources for regional geothermal anomalies. The NE‐oriented crustal thermally‐dominated faults are critical for the formation of geothermal anomalies and NW‐oriented extensional faults have created favorable conditions for meteoric water infiltration, transportation and the formation of thermal springs. [ABSTRACT FROM AUTHOR]

Nowadays, polyurethanes with multifunctional and multiple shape memory effects, especially those without the use of toxic phosgene and isocyanate, have attracted significant attention. In this work, to prepare a kind of non‐isocyanate polyurethane (NIPU) with triple shape memory effect, we introduced the behenic acid (BA) with good crystallinity into the NIPUs network, which combines glass transition of the cross‐linked network and crystallization‐melting of behenic acid, endowing the NIPUs with two independent transition temperatures: the glass transition temperature (Tg) and crystallization melting temperature (Tm). Specifically, the NIPUs were synthesized by the addition reaction of bi‐functional cyclic carbonate and semi‐crystalline curing agent. The bi‐functional cyclic carbonate was prepared by thiol‐ene click reaction, and the BA was grafted onto polyethyleneimine to prepare semi‐crystalline curing agent. By adjusting the ratio of BA to PEI and curing temperature, the crystallinity of NIPU can be tuned in a wide range, so that the NIPUs has tunable and superior triple shape memory performance, and the shape recovery rate is almost 100%. [ABSTRACT FROM AUTHOR]

The low tensile strength of ethylene/α‐octene co‐polymer (POE) limits its application as high‐strength materials. In this study, 3‐amino‐1,2,4‐triazole (ATA) was grafted onto maleic anhydride functionalized POE (PM) by melt reaction to obtain side chains capable of forming hydrogen bonding and metal coordination bonding, and then ferric chloride hexahydrate and POE are blended with them to obtain composite materials with high strength and fracture energy. The introduction of iron‐based coordination bonding and hydrogen bonding double dynamic crosslinking network endow thermoplastic elastomers with excellent mechanical strength and high toughness. Fourier transform infrared spectroscopy, rheological tests, and X‐ray photoelectron spectroscopy reveal the existence of non‐covalent crosslinking networks. Based on the strengthening and toughening of non‐covalent dynamic crosslinking network, the tensile strength of the modified POE elastomer composites achieves 12.5 MPa along with the elongation at break of 3540%. In addition, the modified POE elastomer composites exhibit improved melt elasticity and thermal stability. [ABSTRACT FROM AUTHOR]

Geothermal resources exist in complex and comprehensive geological settings. In the current study, we proposed a CPU/GPU collaborative parallel prestack time migration methodology for geothermal resource exploration. First, seismic geological conditions in Xian County were obtained based on an analysis of drill cores for further seismic evaluation. Then, combined with the analysis of two‐dimensional seismic data in the adjacent area, a test section with three seismic survey lines were designed to explore the geological structure of the study area. In the study area, the seismic data were derived through the multiple coverage reflection wave exploration method with explosive ignition in deep wells and high coverage frequency observations. Finally, we employed CPU/GPU collaborative parallel prestack time migration technology to analyze the obtained seismic data for geothermal resource evaluation. The favorable areas of karst fissure heat storage in Middle–Upper Proterozoic Jixianian and Paleozoic Cambrian–Ordovician rocks were inferred together with two preferred recommended exploration holes. [ABSTRACT FROM AUTHOR]

Herein this study, plasmonic‐patterned nanostructures are applied to fabricate unclonable anti‐counterfeiting labels. Patterned Au nanoparticles (AuNPs) are constructed by the skillful combination of diblock copolymer polystyrene‐block‐poly(4‐vinyl pyridine) (PS‐b‐P4VP) self‐assembly with shadow mask lithography to provide a simple and universal approach for large‐area fabrication of patterned nanostructures. The AuNP pattern can be made visible by increasing the nanoparticle size. A surface‐enhanced Raman spectroscopy (SERS)‐based physical unclonable function (PUF) security label with a large encoding capacity is fabricated by depositing malachite green (MG) on the surface. The broadening of the size distribution of the AuNPs after their growth and the increased disorder in their arrangement confer the security label with unique and unclonable characteristics. The as‐prepared optical PUF security label is read out by a confocal Raman spectrometer to extract binary codes, which are then authenticated through comparison. These SERS‐based PUF security labels, which combine patterning with stochastic spectral encoding, not only provide rich and diverse patterns but are also promising for anti‐counterfeiting applications in areas such as rigid silicon‐based optoelectronic materials and devices. [ABSTRACT FROM AUTHOR]

Subducted remnant slabs play an important role in the geodynamics and evolution of the Earth, but their behaviour in the mantle is not well understood. Terrestrial heat flow and thermal lithosphere structure provide crucial constraints on lithospheric dynamics. Based on whole‐well steady‐state temperature logs and conductivity measurements of core samples from a scientific borehole, we obtained a new high‐quality terrestrial heat flow values for East Asia. The heat flow was calculated at 60.6 ± 16.0 mW/m2 with a high crust/mantle heat flow ratio of 1.41, suggesting a hot‐crust‐cold‐mantle lithospheric structure. The thermal lithospheric thickness of eastern Fujian is estimated to be 152–166 km, indicating a thick and cold lithosphere. We demonstrate that the cooling of the lithosphere is caused by a remnant palaeo‐slab of the Palaeo‐Pacific plate subducted beneath SE China. The remnant slab blocked heat convection into the bottom of the lithosphere of the Eurasian Plate. [ABSTRACT FROM AUTHOR]

Thermoplastic elastomer ethylene/α‐octene co‐polymer (POE) is a special polymer material with both elasticity and thermoplasticity. However, the nonpolarity and low‐tensile strength of POE limit its application in polar materials and high‐strength materials fields. In this study, we synthesized a specific molecule with C═C bonds and NH bonds, which was introduced into POE to construct hydrogen bonding network, and the prepared modified POE is further blended with carboxyl terminated polystyrene nanospheres as toughening agent to prepare modified POE elastomer composites. Based on such dual toughening strategy containing chemical modification and physical toughening, the modified POE elastomer composites possess improved mechanical properties. The composites achieve a tensile strength of 21.4 MPa, elongation at break of 1268%, fracture energy of 109.6 MJ∙m−3 and exhibit improved thermal stability. Impressively, the tensile strength of reprocessed composites is restored to more than 90% of their original tensile strength even after four times of reprocessing steps, demonstrating excellent reusability. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (GNPs), usually fabricated through reduction and stabilization two steps, have been widely used in biomedical field. Here, the six‐armed star copolymer was synthesized and self‐assembled into crosslinked micelles for the in‐situ preparation of GNPs in one‐step without external reductant. The copolymer and their precursors were synthesized by a combination of ring‐opening polymerization (ROP), activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP), and Michael addition reaction. Their molecular weights and structures were measured by gel permeation chromatography (GPC) and 1H NMR. The diselenide bond of crosslinked micelles reduced AuCl4− to GNPs, and the crosslinked micelles stabilized the GNPs in‐situ. Through increasing AuCl4− concentration, the collision probability between the GNPs increased, with particle diameters of 1.5, 2.3, and 3.0 nm. Moreover, the GNPs showed good stability, and the wavelength of maximum absorbance (λmax) did not change under different dilution, temperature, and storage conditions. Furthermore, integrating dissipative particle dynamics (DPD) simulations and scripts with experiments, the formation process of crosslinked micelles, the stabilization process, and the size regulation of GNPs at mesoscopic scale were revealed. Therefore, this stable crosslinked micelles/GNPs hybrid material is expected to be used as a nanocarrier in an integrated diagnosis and treatment system. [ABSTRACT FROM AUTHOR]

Hot dry rock (HDR) is an important geothermal resource and clean energy source that may play an increasingly important role in future energy management. High‐temperature HDR resources were recently detected in deep regions of the Gonghe Basin on the northeastern edge of the Tibetan Plateau, which led to a significant breakthrough in HDR resource exploration in China. This research analyzes the deep temperature distribution, radiogenic heat production, heat flow, and crustal thermal structure in the Qiaboqia Valley, Guide Plain, and Zhacanggou area of the Gonghe Basin based on geothermal exploration borehole logging data, rock thermophysical properties, and regional geophysical exploration data. The results are applied to discuss the heat accumulation mechanism of the HDR resources in the Gonghe Basin. The findings suggest that a low‐velocity layer in the thickened crust of the Tibetan Plateau provides the most important source of constant intracrustal heat for the formation of HDR resources in the Gonghe Basin, whereas crustal thickening redistributes the concentrated layer of radioactive elements, which compensates for the relatively low heat production of the basal granite and serves as an important supplement to the heat of the HDR resources. The negative effect is that the downward curvature of the lithospheric upper mantle caused by crustal thickening leads to a small mantle heat flow component. As a result, the heat flows in the Qiaboqia Valley and Guide Plain of the Gonghe Basin are 106.2 and 77.6 mW/m2, respectively, in which the crust‐mantle heat flow ratio of the former is 3.12:1, indicating a notably anomalous intracrustal thermal structure. In contrast, the crust‐mantle heat flow ratio in the Guide Plain is 1.84:1, which reflects a typical hot crust‐cold mantle thermal structure. The Guide Plain and Zhacanggou area show the same increasing temperature trend with depth, which reflects that their geothermal backgrounds and deep high‐temperature environments are similar. These results provide important insight on the heat source mechanism of HDR resource formation in the Tibetan Plateau and useful guidance for future HDR resource exploration projects and target sites selection in similar areas. [ABSTRACT FROM AUTHOR]

The fabrication of flexible surface‐enhanced Raman scattering (SERS) substrates for sensitive detection on uneven or irregular surfaces is challenging. In this study, a flexible dual plasmonic SERS (FDPS) substrate rationally constructed using Au nanoparticle (AuNP) arrays/aligned Ag nanowires (AgNWs) and elastic polyurethane (PU) is demonstrated. It exhibits high sensitivity (detection limit of 10−8m for melamine and 10−10m for malachite green) and excellent reproducibility. The well‐designed structure of AuNP arrays/aligned AgNWs fabricated using block copolymer self‐assembly and oil–water–air interfacial self‐assembly successfully enhances the electromagnetic field through plasmonic coupling. In addition, the FDPS substrate retains a high SERS sensitivity after exposure to air at room temperature for 30 days because of the high stability of AuNP arrays and antioxidation characteristic of the PU covered on the aligned AgNWs. Even after undergoing stretching, bending, and twisting for 100 cycles, the FDPS substrate maintains a stable SERS activity owing to the introduction of the elastic PU. This study demonstrates a potential application of SERS detection under practical conditions for irregular surfaces and may be helpful in the development of flexible sensors. [ABSTRACT FROM AUTHOR]

SUMMARY: Loss of chlorophyll (Chl) is a hallmark of leaf senescence, which may be regulated by Chl catabolic genes, including NON‐YELLOW COLORING 1 (NYC1)‐like (NOL). The objective of this study was to determine molecular factors and metabolic pathways underlying NOL regulation of leaf senescence in perennial grass species. LpNOL was cloned from perennial ryegrass (Lolium perenne L.) and found to be highly expressed in senescent leaves. Transient overexpression of LpNOL accelerated leaf senescence and Chl b degradation in Nicotiana benthamiana. LpNOL RNA interference (NOLi) in perennial ryegrass not only significantly blocked Chl degradation in senescent leaves, but also delayed initiation and progression of leaf senescence. This study found that NOL, in addition to functioning as a Chl b reductase, could enact the functional stay‐green phenotype in perennial grass species, as manifested by increased photosynthetic activities in NOLi plants. Comparative transcriptomic analysis revealed that NOL‐mediated functional stay‐green in perennial ryegrass was mainly achieved through the modulation of Chl catabolism, light harvesting for photosynthesis, photorespiration, cytochrome respiration, carbohydrate catabolism, oxidative detoxification, and abscisic acid biosynthesis and signaling pathways. Significance Statement: Chlorophyll (Chl) degradation is a hallmark of leaf senescence. Here, we demonstrated that blocking a Chl catabolic gene, LpNOL, in perennial ryegrass results in functional stay‐green associated with metabolic modulation of Chl metabolism, light harvesting, photorespiration, cytochrome respiration, carbohydrate catabolism, oxidative detoxification, and abscisic acid biosynthesis and signaling to maintain the ability of photosynthesis and reactive oxygen species clearance, and metabolic energy supply, while inhibiting sugar accumulation. [ABSTRACT FROM AUTHOR]

ABSTRACT Multifunctional polymer unimolecular micelles, which are used as templates to fabricate stable gold nanoparticles (GNPs) in one-step without external reductant, have been designed and prepared. Amphiphilic 21-arm star-like block copolymers β-cyclodextrin-{poly(lactide)-poly(2-(dimethylamino) ethyl methacrylate)-poly[oligo(2-ethyl-2-oxazoline)methacrylate]}21 [β-CD-(PLA-PDMAEMA-PEtOxMA)21] and the precursors are synthesized by the combination of ring-opening polymerization (ROP) and activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). The tertiary amine groups of PDMAEMA block reduce the [ABSTRACT FROM AUTHOR]

Multiple-input multiple-output (MIMO) transmission techniques constitute an important technology in modern wireless communication. Hence, performance analysis methods for such systems are of considerable interest. This paper considers first the average pairwise error probability for uncoded MIMO systems employing maximum likelihood detection over a composite Rayleigh-Lognormal fading channel with spatial correlation. It provides general results, applicable also to a wider class of shadowing models, concerning asymptotical diversity gains and shows that they are not changed by such shadowing. Then, analytical evaluation techniques for bit-error-rate (BER) over composite Rayleigh-Lognormal fading channels, based on the truncated union bound and the transfer function, are considered. Furthermore, these techniques are modified for applications over spatially correlated channels. This paper shows that such performance evaluation techniques provide good approximations to BER of spatially uncorrelated MIMO systems and also in the presence of moderate spatial correlation, over Rayleigh-Lognormal fading channels. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Acrylic macromonomer was synthesized by esterification of acrylic acid (AA) and PEGylated siloxane alcohol. And the acrylic macromonomer was employed as unsaturated precursor for the hydrosilylation with polymethylhydrosiloxane (PMHS). FTIR, 1H, 13C, 29Si‐NMR, and TGA proved that PEGylated polysiloxane was successfully synthesized. The morphological studies revealed that the dimples in the cross sections were attributed to polyethylene glycol (PEG) phase domains with diameters of 5–15 μm. The contribution of polar and dispersion factor toward surface energy was studied by contact angle (CA) measurement. The results showed that wetting behavior could transform from hydrophobic to hydrophilic with the CA from 122° to 54°. The final PEGylated polysiloxane provided sufficient compatibility and good wetting behavior, in contrast with silane ethers or alkyl silanes, indicating that it might be utilized as an alternate candidate for personal care. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47889. [ABSTRACT FROM AUTHOR]