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The rearrangement of drainage basins provides critical insight into crustal deformation and geodynamic mechanisms. Near the southeastern boundary of the Tibetan Plateau, the Dadu River abruptly shifts from south- to east-flowing, providing important implications for regional tectonogeomorphic development since the mid-Pleistocene. South of the bend, the headwaters of the Anning River occupy an unusually wide valley. Field investigations show that large quantities of fluvial/lacustrine sediments are widespread along the Dadu and Anning rivers and are exposed at their drainage divide. Detrital zircon U-Pb age patterns confirm that these fluvial/lacustrine sediments are the remnants of the paleo-Dadu River, which strongly suggests that the paleo-Dadu River originally flowed southward into the Anning River. The cosmogenic nuclide burial ages of the lacustrine sediments along the Dadu and Anning rivers suggest deposition of these sediments from separate dammed lakes ca. 1.2 Ma ago, ca. 0.6 Ma ago, and ca. 0.9 Ma ago from north to south, respectively. Provenance and burial-age studies indicate that reorganization of the Dadu drainage occurred within the last 0.6 Ma. We propose that this drainage reorganization in southeastern Tibet resulted from progressive convergence between the India and Eurasian plates during the Pleistocene.

A novel multifunctional KNN-based ceramics with decent piezoelectricity and intriguing photoluminescence are achieved through simultaneous modulation of diffused phase transition behavior and unit cell distortion via optimizing the Dy3+ content.

Chaotic systems are dynamic systems with aperiodic and pseudo-random properties, and systems in many fields exhibit chaotic time-series properties. Aiming at the fuzzy modeling problem of chaotic time series, this paper proposes a new fuzzy identification method considering the selection of important input variables. The purpose is to achieve higher model modeling and prediction accuracy by constructing a model with a simple structure. The relevant input variable was swiftly chosen in accordance with the input variable index after the Two Stage Fuzzy Curves method was used to determine the weight of the correlation between each input variable and the output from a large number of selectable input variables. The center and width of the irregular Gaussian membership function were then optimized using the fuzzy C-means clustering algorithm and the particle swarm optimization technique, which led to the determination of the fuzzy model’s underlying premise parameters. Finally, the fuzzy model’s conclusion parameters were determined using the recursive least squares method. This model is used to simulate three chaotic time series, and the outcomes of the simulation are contrasted and examined. The outcomes demonstrate that the fuzzy identification system has higher prediction accuracy based on a simpler structure, demonstrating its validity.

Two-dimensional (2D) materials with multiphase, multielement crystals such as transition metal chalcogenides (TMCs) (based on V, Cr, Mn, Fe, Cd, Pt and Pd) and transition metal phosphorous chalcogenides (TMPCs) offer a unique platform to explore novel physical phenomena. However, the synthesis of a single-phase/single-composition crystal of these 2D materials via chemical vapour deposition is still challenging. Here we unravel a competitive-chemical-reaction-based growth mechanism to manipulate the nucleation and growth rate. Based on the growth mechanism, 67 types of TMCs and TMPCs with a defined phase, controllable structure and tunable component can be realized. The ferromagnetism and superconductivity in FeXy can be tuned by the y value, such as superconductivity observed in FeX and ferromagnetism in FeS2 monolayers, demonstrating the high quality of as-grown 2D materials. This work paves the way for the multidisciplinary exploration of 2D TMPCs and TMCs with unique properties. Ministry of Education (MOE) National Research Foundation (NRF) Submitted/Accepted version This work was supported by the National Key R&D Program of China (grant no. 2020YFA0308800) and the NSF of China (grant nos. 62174013, 11504046 12061131002 and 11734003). This work was also supported by the National Research Foundation— Competitive Research Program (NRF-CRP22-2019-0007, NRF-CRP21-2018-0007 and NRF2020-NRF-ISF004-3520). This work was also supported by the Singapore Ministry of Education Tier 3 Programme ‘Geometrical Quantum Materials’ (MOE2018-T3-1-002), AcRF Tier 2 (MOE2019-T2-2-105) and AcRF Tier 1 RG161/19 and RG7/21. W.B.G. acknowledges the support of NRF CRP by NRF-CRP22-2019-0004. G.L. and L. Lu acknowledge fundings from the National Natural Science Foundation of China under grant numbers 92065203 and 11874406, and the Strategic Priority Research Program of the Chinese Academy of Sciences (grant no. XDB33010300). Y.Y. was supported by the National Key R&D Program of China (grant no. 2016YFA0300600). C.Z. acknowledges the Fundamental Research Funds for the central Universities. F.D. and J.D. acknowledge funding from the Institute for Basic Science, Republic of Korea (IBS‐R019‐D1) and the use of the IBS‐CMCM high‐performance computing system Cimulator. This work was also supported by the Innovation Program of Shanghai Municipal Education Commission (no. 2019-01-07-00-09-E00020) and Shanghai Municipal Science and Technology Commission (18JC1412800). Y.-C.L. and K.S. acknowledge JSPS-KAKENHI (JP16H06333 and 18K14119), JSPS A3 Foresight Program and Kazato Research Encouragement Prize. H. Yang acknowledges funding from the Chinese Academy of Sciences (grant nos. XDB33030100). Y.Y. acknowledges the Strategic Priority Research Program of the Chinese Academy of Sciences (grant no. XDB30000000).

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link. This paper presents the L1-gain polynomial fuzzy output feedback controller design and the stability analysis using sum-of-squares (SOS) approach for positive polynomial fuzzy-model-based (PPFMB) control systems. The polynomials, positivity and optimal L1 performance makes some existing convex methods for general systems inapplicable. To overcome this problem, an augmented system of the positive polynomial fuzzy-model-based control system is first constructed, then by introducing some constrain conditions and mathematical tech niques, the non-convex stability and positivity conditions are skill fully transformed into convex ones simultaneously. In addition, to control the systems flexibly and lower the implementation cost, the imperfect premise matching concept is taken into account for controller design. Besides, the high degree polynomial approximation method is adopted to conduct stability and posi tivity analysis by incorporating the information of membership functions (MFs) and the boundary information of the state variables. On the basis of the Lyapunov stability theory, the relaxed stability and positivity conditions in terms of SOS are obtained. Finally, a simulation example is presented to verify the feasibility of the theoretical results

Nonlinear positive control system can be found in many real-world applications but the positivity requirements lead to challenges in system analysis and control design. In this paper, we approach the problem by fuzzy-model-based control techniques and overcome some challenges including transforming the non-convexity conditions when both positive and stability conditions exist into convexity conditions that can be solved by the convex programming techniques. This paper focuses on the static output-feedback tracking control issue of positive polynomial fuzzy-model-based (PPFMB) systems. The purpose of the tracking control is to design an appropriate static output feedback polynomial fuzzy controller which can drive the system states of the nonlinear plant to follow those of a stable reference model subject to an $H_\infty$ performance. The concept of imperfectly matched premises is employed to enhance the design and implementation flexibility. To circumvent the problem of non-convex stability conditions, an approach is employed to transform the non-convex stability conditions into convex ones by introducing a novel Scalar Implantation Transformation (SIT) technique. Besides, the partition approximation of membership functions with local information of membership functions is used to promote stability analysis and synthesis of controllers. The positive and relaxed stability conditions for static outputfeedback tracking control with $H_\infty$ performance being taken into account are obtained in terms of sum-of-squares (SOS). Finally, a simulation example is presented to verify the effectiveness of the proposed tracking control approach.

The recombination of charge carriers arriving from the random charge movement in semiconductor photocatalysts greatly limits the practical application of solar-driven H2 evolution. The design of photocatalytic systems with spatially oriented charge-transfer is a promising route to achieve high charge-separation efficiency for photocatalysts. Herein, novel sea-urchin-like ReS2 nanosheet/TiO2 nanoparticle heterojunctions (SURTHs) are constructed. The unique sea-urchin-like structure endows the ReS2 cocatalyst with an unusual charge edge-collection effect, which leads to a significant acceleration of charge separation and transfer, as evidenced by the well-designed selective photodeposition of Pt quantum dots in SURTHs. The markedly improved charge transfer capacity contributes to a high photocatalytic H2 evolution rate of 3.71 mmol h−1 g−1 for SURTHs (an apparent quantum efficiency (AQE) of 16.09%), up to 231.9 times by contrast with that of P25 TiO2. This work would provide a new platform for designing the high-efficiency cocatalyst/photocatalyst system with excellent charge transfer capacity. This work was funded by the China Postdoctoral Science Foundation (pre-station, No. 2019TQ0050), Applied Basic Research Program of Sichuan Province (No. 2020YJ0068), the China Postdoctoral Science Foundation (No. 2020M673186), National Natural Science Foundation of China (No. 22002014), the Applied Basic Research Program of Sichuan Province (No. 2020ZYD014). Thanks for the technical help from Sichuan Province Key Laboratory of Display Science and Technology, State Key Laboratory of Electronic Thin Films and Integrated Devices. Dr. Xiao Luo acknowledges financial support from the National Natural Science Foundation of China (No. 21903084) and Applied Basic Research Program of Sichuan Province (No. 2021YJ0408). Dr. Qing Liu acknowledges financial support from the National Natural Science Foundation of China (No. 52002051) and the Fundamental Research Funds for the Central Universities, SCUT (No. ZYGX2020J009).

This paper focuses on expanding the estimation of the domain of attraction (DOA) for discrete-time positive nonlinear systems subject to input saturation and parameter uncertainties. To facilitate analysis and design, the interval type-2 (IT2) polynomial fuzzy model is used to represent the nonlinear plant and capture uncertainties. Combining with the IT2 polynomial fuzzy controller, the discrete-time positive IT2 polynomial fuzzy-model-based (PIT2PFMB) control system is formed to facilitate analysis. To enlarge the estimation of DOA of the discrete-time PIT2PFMB system, polyhedron is used to characterize the DOA with the help of linear copositive Lyapunov function (LCLF). Referring to the non-convex conditions derived by LCLF, an effective convexification method is proposed in this paper. For comparison purposes, the saturation-dependent-Lyapunov-function-based method is extended to the PIT2PFMB control system by adding the corresponding positivity conditions. In addition, this paper attempts to enlarge the estimation of the DOA by improving the IT2 membership-function-dependent (IT2MFD) method and extending it to all conditions including the stability conditions and the DOA estimation conditions. Finally, an example with simulation results is given to verify the effectiveness of all the methods proposed in this paper for expanding the estimation of the DOA.

Defect states dominate the performance of low-dimensional nanoelectronics, which deteriorate the serviceability of devices in most cases. But in recent years, some intriguing functionalities are discovered by defect engineering. In this work, we demonstrate a bifunctional memory device of a MoS2/BiFeO3/SrTiO3 van der Waals heterostructure, which can be programmed and erased by solely one kind of external stimuli (light or electrical-gate pulse) via engineering of oxygen-vacancy-based solid-ionic gating. The device shows multibit electrical memory capability (>22 bits) with a large linearly tunable dynamic range of 7.1 × 106 (137 dB). Furthermore, the device can be programmed by green- and red-light illuminations and then erased by UV light pulses. Besides, the photoresponse under red-light illumination reaches a high photoresponsivity (6.7 × 104 A/W) and photodetectivity (2.12 × 1013 Jones). These results highlighted solid-ionic memory for building up multifunctional electronic and optoelectronic devices. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) National Research Foundation (NRF) Submitted/Accepted version This research was supported by National Research Foundation Singapore Grants NRF-CRP22-2019-0007 and NRF-CRP21- 2018-0007, Singapore Ministry of Education via AcRF Tier 3 Programme “Geometrical Quantum Materials” (Grant MOE2018-T3-1-002), AcRF Tier 2 (Grant MOE2016-T2-1- 131), and AcRF Tier 1 Grants RG4/17 and RG7/18. This research is also supported by A*STAR under its AME IRG Grant (Project A2083c0052). This work was also financially supported by the National Key R&D Program of China (Grant 2020YFA0309200), the National Natural Science Foundation of China (Grant 62074025), Applied Basic Research Program of Sichuan Province (Grant 2020ZYD014), and Sichuan Province Key Laboratory of Display Science and Technology.

2D metal thiophosphate SnP2S6 was discovered as a new dielectric layer with a high dielectric constant (≈23), realizing a low subthreshold slope down to 69.4 mV dec−1 in the field effect transistor device geometry.

Benzotriazole-EDOT electrochromic conjugated polymers of PBTz-E and P2F-BTz-E were developed by direct arylation polymerization. PBTz-E showed coloration efficiency of 774 cm2 C−1. Flexible ECDs were prepared and demonstrated excellent electrochromic properties.

This article investigates the polynomial fuzzy output feedback (PFOF) control synthesis problem for positive polynomial fuzzy systems. When the states of a positive system cannot be fully obtained, the output feedback control strategy is a good method to stabilize the control system. From fuzzy control point of view, we employ the polynomial fuzzy model rather than the Takagi–Sugeno fuzzy model, and this kind of models can express a wider range of nonlinear positive systems. However, the polynomials in the system matrices and the feedback control gain matrices will make the nonconvex stability conditions more difficult to deal with. Thereby, in order to crack the hard nut, a nonzero transformation vector is introduced in this article to deal with the nonconvex problem skillfully. Furthermore, the imperfect premise matching technique is taken into account so that the implement of the controller is more simple and money-saving. In addition, the augmented dynamic of the positive polynomial fuzzy-model-based (PPFMB) control system is investigated to facilitate the stability and positivity analysis, and the basic conditions in the light of sum of squares (SOSs) are derived. Besides, the advanced membership function dependent (MFD) technique is used so that a great of useful information of MFs is extracted to improve the relaxation of the results. Finally, the effectiveness of the theoretical findings is illustrated by a simulation example.

In this article, we investigate the stability analysis of a polynomial-fuzzy-model-based control system by employing a new form of approximate membership functions called Chebyshev membership functions (CMFs) based on the Lyapunov stability theory. The membership-function-dependent method shows that the approximate functions can introduce useful information to relax the conservativeness of stability analysis. Therefore, in the case of the same order and operating domain, how to design the approximate functions to introduce more information to relax stability is a concern. In this article, given the Chebyshev norm relationship between the approximate membership functions and the original ones, CMFs can be obtained by the Chebyshev approximation theory and the Remez/Remez-type iterative algorithm, which own the minimum of the maximum absolute approximation error. Together with CMFs, the boundary information of premise variables on the overall operating domain is considered to reduce the conservativeness of stability analysis. Furthermore, to further relax the stability analysis without increasing the order of CMFs, the operating domain is divided into subdomains, and piecewise Chebyshev membership functions (PCMFs) are proposed to facilitate the stability analysis. Together with PCMFs, the subdomain boundary information of premise variables is introduced into stability conditions. A simulation example is given to demonstrate the effectiveness of the proposed approach.

Low-efficiency charge transfer is a critical factor to limit the photocatalytic H2 evolution activity of semiconductor photocatalysts. The interface design is a promising approach to achieve high charge-transfer efficiency for photocatalysts. Herein, a new 2D/2D atomic double-layer WS2/Nb2O5 shell/core photocatalyst (DLWS/Nb2O5) is designed. The atom-resolved HAADF-STEM results unravel the presence of an unusual 2D/2D shell/core interface in DLWS/Nb2O5. Taking advantage of the advanced femtosecond-resolved ultrafast TAS spectra, the average lifetime of charge carriers for DLWS/Nb2O5 (180.97 ps) is considerably shortened as compared to that of Nb2O5 (230.50 ps), strongly indicating that the 2D/2D shell/core interface enables DLWS/Nb2O5 to achieve ultrafast charge transfer from Nb2O5 to atomic double-layer WS2, thus yielding a high photocatalytic H2 evolution rate of 237.6 μmol/h, up to 10.8 times higher than that of pure Nb2O5 nanosheet. This study will open a new window for the development of high-efficient photocatalytic systems through the interface design.

The electromagnetic spectrum between microwave and infrared light is termed the "terahertz (THz) gap," of which there is an urgent lack of feasible and efficient room-temperature (RT) THz detectors. Type-II Weyl semimetals (WSMs) have been predicted to host significant RT topological photoresponses in low-frequency regions, especially in the THz gap, well addressing the shortcomings of THz detectors. However, such devices have not been experimentally realized yet. Herein, a type-II WSM (NbIrTe

With the rising demand for renewable energy, photocatalysts are considered the most promising solution to harness solar energy, and the search for photocatalysts with excellent performances remains an urgent task. Here, based on density functional theory (DFT), the photocatalytic properties of MoWS4 are systematically investigated. The MoWS4 monolayer and bilayer are demonstrated as semiconductors with indirect band gaps of 2.01 and 1.48 eV. Moreover, they exhibit high and anisotropic light absorption coefficients of up to ∼105 cm−1 in the visible-ultraviolet region. The intrinsic band edge positions could fully satisfy the redox potentials of water without any external adjustment. The electron mobility of MoWS4 monolayer is 557 cm2 V−1s−1, which is seven times higher than MoS2 monolayer. Hence, MoWS4 can be regarded as a promising 2D photocatalyst candidate for water splitting.

Milling of titanium alloys is usually associated with a high cutting temperature and severe tool wear. Therefore, flood cooling technologies were conventionally employed for prolonging the tool life and improving the machined surface quality. However, a negative impact on the environment and waste disposal problems caused by a vast quantity of metalworking fluids used in the process has become significant. In this study, a new machining method called “cold air electrostatic minimum quantity lubrication (CAEMQL)” is proposed for machining titanium alloys Ti-6Al-4V. The milling performance of CAEMQL was systematically assessed in terms of cutting force, cutting temperature, surface roughness, tool life, tool wear and chip morphology, using minimum quantity lubrication (MQL), electrostatic minimum quantity lubrication (EMQL) and cold air minimum quantity lubrication (CAMQL) as benchmarks. It was found that CAEMQL resulted in an improved critical heat flux and steady-state heat transfer performance compared with MQL, EMQL and CAMQL, which thus produced a lower milling force, smaller milling temperature, better surface quality and less tool wear. The degrees of chip segmentation were enhanced with less deformation for CAEMQL due to its synergistic cooling and lubrication effect .

With forming-free, self-rectifying, and self-compliant properties, memristors can effectively prevent themselves from experiencing leakage currents and overshoot voltages without any additional circuitry. However, the implementation of all these features in a single memristor remains a challenge. Herein, a multifunctional Si

A steel–concrete composite box girder has good anti-seismic energy dissipation capacity, absorbs seismic energy, and reduces seismic action. It is very suitable for high-rise and super high-rise mega composite structure systems, which is in accordance with the condition of capital construction. In order to accurately study the elastic–plastic seismic response of the composite structure, the restoring force model of the building structure is the primary problem that needs to be solved. Previous research shows that shear connection degree, force ratio, and web height–thickness ratio are the major factors that influence composite box girder bearing capacity and seismic behavior. In this paper, low cycle vertical load tests of four steel–concrete composite box girders were conducted with different shear connection degrees and ratios of web height to thickness. The seismic behavior of a steel–concrete composite box girder was analyzed in depth, such as the hysteresis law, skeleton curve, and stiffness degradation law, etc. The influence of the shear connection degree and ratio of web height to thickness on seismic performance of the steel–concrete composite box girder was investigated. A three-fold line model of the bending moment–curvature skeleton curve of composite box girders was established. On the basis of experimental data and theoretical analysis, the formula of positive and negative stiffness degradation of composite box girders was obtained. Furthermore, the maximum point orientation hysteresis model of the bending moment–curvature of steel–concrete composite box girders was established. The calculated results of the restoring force model agree well with the experimental results. The accuracy of the proposed method is verified. The calculation method of the model is simple and clear, convenient for hand calculation, and suitable for engineering applications.

Cocatalyst design is a key approach to acquire high solar-energy conversion efficiency for photocatalytic hydrogen evolution. Here a new in situ vapor-phase (ISVP) growth method is developed to construct the cocatalyst of 2D PtS nanorectangles (a length of ∼7 nm, a width of ∼5 nm) on the surface of g-C3N4 nanosheets. The 2D PtS nanorectangles/g-C3N4 nanosheets (PtS/CN) show an unusual metal sulfide–support interaction (MSSI), which is evidenced by atomic resolution HAADF-STEM, synchrotron-based GIXRD, XPS and DFT calculations. The effect of MSSI contributes to the optimization of geometrical structure and energy-band structure, acceleration of charge transfer, and reduction of hydrogen adsorption free energy of PtS/CN, thus yielding excellent stability and an ultrahigh photocatalytic H2 evolution rate of 1072.6 μmol h−1 (an apparent quantum efficiency of 45.7% at 420 nm), up to 13.3 and 1532.3 times by contrast with that of Pt nanoparticles/g-C3N4 nanosheets and g-C3N4 nanosheets, respectively. This work will provide a new platform for designing high-efficiency photocatalysts for sunlight-driven hydrogen generation.

Seawater and sea sand concrete (SWSSC) filled ultra-high performance concrete (UHPC) tube (SFUHPC tube) column is a cement-based tubular composite column, which combines the excellent compressive strength and toughness of UHPC and lateral confining action from fiber reinforced polymer (FRP) hoops. The novel composite system has the potential to be used in marine engineering. The aims of this paper focus on evaluating the seismic performance of SFUHPC tube columns for being designed in costal and marine engineering. A series of low-cycle reversed lateral loading tests were conducted on five relatively large-scale specimens. FRP hoop volumetric ratio, compressive strength of filling SWSSC, and the types of FRP bar were selected as test parameters in this investigation. The failure modes, hysteretic responses and effects of main parameters were studied and discussed. SFUHPC tube columns exhibited flexural failure mode without visible spalling of the UHPC cover. It is noteworthy that the limit plastic drift ratios of all SFUHPC tube columns exceed the specified limits (0.02) in accordance to the rare earthquake requirement in seismic design code. The current study reveals that the proposed composite columns have acceptable ductility and relatively reliable lateral resistant performance for being used in the marine engineering. From the point of view of seismic performance, filling high strength SWSSC in UHPC tube is acceptable for the proposed composite system.

This study addresses an observer-based model predictive control (MPC) algorithm for a networked control system (NCS) under denial of service (DoS) attacks and actuator saturation via an interval type-2 Takagi–Sugeno (IT2 T–S) fuzzy model. With few studies undertaking the cyber security problems in the research of MPC algorithm, this study considers the data transmission problem when DoS attacks occur. Under DoS attacks, signals in the communication networks will be interfered. The probability of error-free packet reception depends on signal-to-interference-plus-noise ratio of the wireless transmission networks. In order to reduce the on-line computation, an off-line fuzzy observer is devised to estimate the system states. Meanwhile, an on-line MPC algorithm is proposed to minimise the performance objective function and obtain the secure model predictive controller gain. Besides, the recursive feasibility is ensured by refreshing the bound of estimation error. Finally, illustrative examples certificate the effectiveness of the presented method.

This paper refers to studying the effect of microgravity on the friction behavior of friction units and to further analyzing the influencing mechanism. The potential factors affecting the friction behavior of the moving joints of space mechanisms in microgravity environment were analyzed. A friction apparatus was designed and manufactured by reducing the complexity and costs. A microgravity test program was designed and performed using the Beijing Drop Tower platform with designing three positioning styles for the friction apparatus by changing the relationship between the normal load and gravity. For each positioning style of the friction apparatus, the friction behavior of friction unit in gravity and microgravity environment was compared. It was found that microgravity can not only change the value of friction, but also affect its dynamic characteristics. For different positioning styles of the friction apparatus, the influencing mechanism of microgravity on friction behavior was different. The normal load or the relative position between the connected bodies of the friction unit could be changed by microgravity, resulting in that the friction behavior was different from that in gravity environment.