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•Carboxylate MOF materials are summarized for OER application for the first time.•The carboxylate MOFs are categorized according to their compositions and structures.•OER properties ...of carboxylate MOFs are exhaustively compared and summarized.•Outlook is provided based on the analysis of the reported data in literature.
As oxygen evolution reaction (OER) being a critical and bottleneck reaction in a wide range of energy applications, searching for highly-efficient OER electrocatalysts is of great significance. Among numerous candidates, metal-organic frameworks (MOFs) have demonstrated outstanding potential due to their exceptional structural advantages. This review summarizes a representative family of MOF materials, the carboxylate-based MOFs and derivatives as electrocatalysts for OER. With various carboxylate-metal coordinations, unique nanostructures can be constructed such as nanosheets, nanorods, polyhedrons, porous frameworks etc., making them suitable as pristine electrocatalysts or as precursors for carbon-composite catalysts. This review begins with a brief introduction on the structural advantages and synthetic approaches of carboxylate-based MOFs, followed by a discussion on recent advances of these materials in OER, where the effects of structural variation on the catalytic activity are emphasized. Furthermore, several types of the corresponding MOF derivatives are summarized. Finally, outlook on the development of carboxylate-based MOFs and derivatives for OER electrocatalysis is provided.
Tactile sensing is a key sensor modality for robots interacting with their surroundings. These sensors provide a rich and diverse set of data signals that contain detailed information collected from ...contacts between the robot and its environment. The data are however not limited to individual contacts and can be used to extract a wide range of information about the objects in the environment as well as the actions of the robot during the interactions. In this article, we provide an overview of tactile information and its applications in robotics. We present a hierarchy consisting of raw, contact, object, and action levels to structure the tactile information, with higher-level information often building upon lower-level information. We discuss different types of information that can be extracted at each level of the hierarchy. The article also includes an overview of different types of robot applications and the types of tactile information that they employ. Finally we end the article with a discussion for future tactile applications which are still beyond the current capabilities of robots.
Practical application of high-energy-density lithium-sulfur (Li–S) battery is greatly impeded by the detrimental shuttling effect and sluggish redox kinetics of polysulfides. Herein, a ...multifunctional Nb2O5-carbon nanotube (CNT) catalytic interface is designed and fabricated onto the separator, which can directly trap the polysulfides and then rapidly catalyze their redox conversion for advanced Li–S batteries. The construction of conductive and catalytic Nb2O5-CNT interface could afford long-distance electron transfer network, strong chemisorptive properties, and rich catalytic sites for accelerating polysulfide conversion kinetics and regulating Li2S nucleation/dissolution. The sulfur cathode with the assistant of Nb2O5-CNT interface could deliver an initial discharge capacity of 1286 mAh g−1 and remain 992 mAh g−1 with a capacity retention of 77.0%, corresponding to a low capacity attenuation rate of 0.23% per cycle during 100 cycles at 0.2C. Meanwhile, the Nb2O5-CNT interface can greatly suppress the self-discharge and effectively reduce the formation of lithium dendrite due to the inhibition of the shuttling effect. This work provides instructive insights to suppress the shuttle effect and accelerate redox conversion via designing a multifunctional catalytic interface for Li–S chemistry.
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Self-assembled and well-aligned nanowires (NWs) of poly(3-hexylthiophenes) (P3HT) embedded within insulating polystyrene (PS) matrix were found to have a high field-effect carrier mobility. We ...demonstrate that solution shear coating of P3HT-NWs/PS nanocomposites is an effective strategy in aligning P3HT NWs in the presence of PS and has a significant impact on the molecular order, morphology, and consequently charge transport. Shear-coated P3HT-NWs/PS nanocomposites consistently exhibited higher carrier mobilities compared to P3HT NWs or pristine P3HT/PS films by up to 10.2-fold. P3HT-NWs/PS nanocomposites containing only 3 wt % P3HT exhibit a mobility of ∼0.053 cm2 V–1 s–1, which is comparable to that of the 30 wt % P3HT (∼0.064 cm2 V–1 s–1) and even higher than that of 100 wt % P3HT (∼0.024 cm2 V–1 s–1).
Oxygen evolution reaction (OER) plays a decisive role in electrolytic water splitting. However, it is still challengeable to develop low-cost and efficient OER electrocatalysts. Herein, we present a ...combination strategy via heteroatom doping, hetero-interface engineering and introducing conductive skeleton to synthesize a hybrid OER catalyst of CNT-interconnected iron-doped NiP2/Ni2P (Fe-(NiP2/Ni2P)@CNT) heterostructural nanoflowers by a simple hydrothermal reaction and subsequent phosphorization process. The optimized Fe-(NiP2/Ni2P)@CNT catalyst delivers an ultralow Tafel slope of 46.1 mV dec−1 and overpotential of 254 mV to obtain 10 mA cm−2, which are even better than those of commercial OER catalyst RuO2. The excellent OER performance is mainly attributed to its unique nanoarchitecture and the synergistic effects: the nanoflowers constructed by a 2D-like nanosheets guarantee large specific area and abundant active sites; the highly conductive CNT skeleton and the electronic modulation by the heterostructural NiP2/Ni2P interface and the hetero-atom doping can improve the catalytic activity; porous nanostructure benefits electrolyte penetration and gas release; most importantly, the rough surface and rich defects caused by phosphorization process can further enhance the OER performance. This work provides a deep insight to boost catalytic performance by heteroatom doping and interface engineering for water splitting.
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•MOF-derived CNT-interconnected Fe-doped NiP2/Ni2P catalyst is synthesized.•Fe-(NiP2/Ni2P)@CNT shows a low Tafel slope and overpotential for OER.•Good OER activity is due to nanostructure, CNT, Fe doping and heterointerface.
The Sichuan basin, located adjacent to the eastern margin of the Tibetan Plateau, serves as an ideal marker for testing the extrusion process of the plateau. The basin is seismically active, with the ...strongest earthquake, the 2008 Mw 7.9 Wenchuan earthquake, occurring in the Longmen Shan range along its northwestern edge. A new regional compilation of focal mechanism solutions of earthquakes in and surrounding the basin reveals that a large fraction of the events have focal depths ranging between 8 and 25 km, corresponding to the crystalline basement of the basin. Seismic deformation involves right‐lateral oblique reverse faults, mostly trending northeast–southwest, similar to the kinematics of the mainshock of the Wenchuan earthquake. Shallow earthquakes (3–8 km) suggest that some of the seismic faults rupturing the crystalline basement are growing toward the surface. To the southwest, the seismicity transitions to activity along the left‐lateral Xianshuihe–Xiaojiang fault zone. The spatial relationship between these two sets of fault zones is consistent with a model in which the Sichuan basin responds to the southeast extrusion of the Chuan‐Dian block at the southeast margin of the plateau by a counterclockwise bookshelf rotation of the crystalline basement. This deformation pattern initiated ∼4–2 Ma, as shown by the age of the Xiaojiang fault segment. The history of left‐lateral movement along the Xianshuihe‐Xiaojiang fault can be traced back to ∼12 Ma when the eastward growth of the Tibetan Plateau resulted in the shortening of both the Longmen Shan thrust belt and the sedimentary over the Sichuan basin.
Plain Language Summary
This Sichuan basin bounds the Tibetan Plateau on the east. A catastrophic earthquake (Mw 7.9) occurred along its boundary in 2008. However, the driving mechanism for this earthquake remains debated. We combine geologic and seismic studies to elucidate the origin of tectonic and seismic activity in the basin. By interpreting the focal mechanism solutions of basin‐internal earthquakes and the surface deformation, and considering the timing of the plateau's extrusion, we propose that the Sichuan basin experienced two stages of counterclockwise rotation in response to the southeastward extrusion of the plateau. The early stage, occurring at ∼12 Ma, involved deformation of the sedimentary cover, while the late stage, initiated ∼4–2 Ma, involved bookshelf rotation of the crystalline basement of the basin.
Key Points
The seismicity of the Sichuan basin is restricted to a depth range of 8–25 km, dominated by the counterclockwise rotation of the basement
The internal deformation is attributed to the southeastward extrusion of the Chuan‐Dian block along the Xianshuihe‐Xiaojiang fault
The rotation history of the Sichuan basin initiated 12 and 4–2 Ma, involving the sedimentary cover and bookshelf rotation of the basement
•C/C-HfC composites were prepared by precursor infiltration and pyrolysis (PIP).•C/C–HfC composites exhibit good ablation resistance for 240s.•During ablation, the formation of HfO2 and HfCxOy ...protected the composites.
C/C–HfC composites were prepared by precursor infiltration and pyrolysis using HfC precursor. The microstructure, mechanical properties, and ablation behavior were investigated. The C/C–HfC composites showed good ablation resistance with a surface temperature over 2573K during ablation. The ablation process was divided into two steps, with the ablation rate dominated by various mechanisms. During ablation, tree-coral-like HfO2 particles formed and functioned as thermal barrier, and the HfCxOy phase acted as oxygen diffusion barrier, protecting the composites from further ablation.
Abstract
The flow state of oil film in the hydrostatic lead screw directly affects the transmission performance of the screw pair. The static and dynamic characteristics of a new type of double ...driven hydrostatic screw-nut pair (DDHSNP) are studied under different motion modes. The boundary condition of navier slip model is introduced into the lubricating mathematical model of DDHSNP, and the influences of boundary slip on the axial bearing capacity, axial stiffness and damping coefficient in micro scale are researched by finite difference method. The results show that when the motor runs at high speed (the rotating speed range of the screw and nut driven motor is 1000–9000 rpm), the existence of boundary slip leads to a improvement of the axial bearing capacity and stiffness coefficient of DDHSNP in the case of single-drive operation and dual-drive differential feed (the range of rotation difference is 10–100 rpm), which is more obvious under the single-drive mode. The increase rate of stiffness coefficient induced by boundary slip is much larger than that of bearing capacity. In addition, the boundary slip has little effect on the damping coefficient of DDHSNP in either single drive operation or dual drive differential operation.
Acute myocardial infarction (AMI) was considered to be one of the major causes of morbidity and mortality worldwide. In order to manage the acute myocardial infarction outbreaks, accurate biomarkers ...for risk prediction are needed. Circulating microRNAs (miRNAs) may act as diagnostic and prognostic biomarkers for cardiovascular events.
This study aimed to determine the possibility of circulating miRNAs used as biomarkers for AMI and their dynamic expression levels before and after percutaneous coronary intervention (PCI) in patients. Circulating miR-26a-1, miR-27a, miR-30d, miR-146a, miR-199a-1 and miR-423 were selected and validated in 31 AMI patients and 27 matched controls by quantitative real-time PCR (qPCR).
The expression levels of plasma miR-26a-1, miR-146a and miR-199a-1 were significantly increased in AMI patients. Receiver operating characteristic (ROC) analysis indicated that miR-26a-1, miR-146a and miR-199a-1 showed considerable diagnostic efficiency for predicting AMI. Furthermore, we demonstrated that the combination of miR-26a-1, miR-146a and miR-199a-1 facilitated AMI diagnosis.
Our findings suggest that circulating miR-26a-1, miR-146a and miR-199a-1 have the potential to be used as biomarkers for AMI diagnosis.
Circulating tumor cells (CTCs) enter peripheral blood from primary tumors and seed metastases. The genome sequencing of CTCs could offer noninvasive prognosis or even diagnosis, but has been hampered ...by low single-cell genome coverage of scarce CTCs. Here, we report the use of the recently developed multiple annealing and looping-based amplification cycles for whole-genome amplification of single CTCs from lung cancer patients. We observed characteristic cancer-associated single-nucleotide variations and insertions/deletions in exomes of CTCs. These mutations provided information needed for individualized therapy, such as drug resistance and phenotypic transition, but were heterogeneous from cell to cell. In contrast, every CTC from an individual patient, regardless of the cancer subtypes, exhibited reproducible copy number variation (CNV) patterns, similar to those of the metastatic tumor of the same patient. Interestingly, different patients with the same lung cancer adenocarcinoma (ADC) shared similar CNV patterns in their CTCs. Even more interestingly, patients of small-cell lung cancer have CNV patterns distinctly different from those of ADC patients. Our finding suggests that CNVs at certain genomic loci are selected for the metastasis of cancer. The reproducibility of cancer-specific CNVs offers potential for CTC-based cancer diagnostics.
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