Abstract: Disclosed is a method for designing a reentry trajectory based on flight path angle planning, including the following steps: S1. extracting an actual operating parameter of an aircraft, setting a maximum dynamic pressure qmax a maximum stagnation point heat flux {dot over (Q)}max, and a maximum overload nmax according to a mission requirement, and solving for a velocity-height boundary of a reentry trajectory; S2. solving for a reentry trajectory in an initial descent stage according to differential equations of reentry motion, and setting up a flight-path-angle lower limit ?min(V) according to the reentry trajectory in the initial descent stage, the velocity-height boundary, and a target point in a velocity-height phase plane; and S3. planning, based on the flight-path-angle lower limit ?min(V), a flight path angle satisfying terminal constraints, and calculating a corresponding bank angle to obtain a reentry trajectory.

Abstract: The present invention provides a radiation resistant high-entropy alloy and a preparation method thereof. A general formula of the radiation resistant high-entropy alloy is TiZrHfVMoTaxNby, where 0.05?x?0.25, 0.05?y?0.5, and x and y are molar ratios. The preparation method of the radiation resistant high-entropy alloy comprises the following steps: mixing Ti, Zr, Hf, V, Mo, Ta, and Nb in order, and conducting vacuum levitation induction melting or vacuum arc melting, to obtain the radiation resistant high-entropy alloy. The high-entropy alloy in the present invention has an excellent irradiation resistance, and does not suffer radiation hardening damage under simulated helium ion irradiation. When helium bubbles are of same sizes as those of conventional alloy, the bubble density of the high-entropy alloy is far lower than that of the conventional alloy, and the lattice constant thereof decreases abnormally after irradiation.

Abstract: The present disclosure provides a device for super cryogenic forming of a metal thin-walled curved surface part, including a super cryogenic medium conveying and pressurizing unit, a press, a die unit and a control system. A blank holder cylinder, a blank holder slide, a deep drawing cylinder and a deep drawing slide are disposed on the press. The die unit includes a male die, a blank holder and a female die. The super cryogenic medium conveying and pressurizing unit includes an autoboosting cryogenic container. A cryogenic channel in the blank holder, a cryogenic channel in the female die and a cavity of the female die are communicated with an outlet of the autoboosting cryogenic container by cryogenic pipes, respectively. A cryogenic pump is disposed on the cryogenic pipe between the cavity of the female die and the autoboosting cryogenic container.

Abstract: A method for predicting a structural failure by a strength-criterion-driven peridynamic model is provided. By building a peridynamic model driven by the strength-criterion of structural materials and then applying geometric and material parameters and working conditions of a structure, a life period from a deformation to a complete break of the structure is predicted. The method is of a high reliability, a wide application range, and a high calculation efficiency. The method simulates an initiation and a propagation of multiple cracks on complex structures under complex load conditions until the structure is destroyed.

Abstract: The present invention discloses a method, device and computer readable storage medium (CRSM) for generating a volume foliation. The method comprises: constructing a pants decomposition graph on a smooth closed surface S of genus g>1, wherein the surface S has g handles, and the pants are a genus-zero triangular mesh surface with g boundaries; constructing an initial mapping f0:(T,g)?(Gr, h) from a tetrahedral mesh T to a graph Gr by a process of extending a topological disk Dk into a solid cylinder Ck; evolving the initial mapping into a generalized harmonic map by the nth iterative mapping; and obtaining a volume foliation of the tetrahedral mesh T from preimages of all nodes of a metric graph (Gr, h) and points on edges of the metric graph (Gr, h) under the generalized harmonic map f.

Abstract: An underwater towing test device including a driving mechanism, an observation platform disposed under the driving mechanism, a towing member, and a towed body. The driving mechanism includes an operation platform, an extended platform connected to the operation platform, a crane, a first railing, a lifebuoy, a control center, a power distribution room, and a plurality of bus ports. The operation platform includes two rail grooves disposed in parallel and a moon pool provided with two pool slots on both ends thereof. The crane includes a chassis provided with a plurality of first guide rollers. The first railing is positioned along the edge of the operation platform and the extended platform, with the lifebuoy hanging thereon. The control center, the power distribution room, the plurality of bus ports, and the moon pool are fixedly disposed on the operation platform.

Abstract: A thermal insulation property measuring device, including a tank, a thermal insulator, a cuboidal frame, a support bracket, and a data collector. The tank includes an upper body, a first lower body, and a second lower body. The thermal insulator includes a first thermal insulation layer, a second thermal insulation layer, a first membrane, a second membrane, and a third membrane. The support bracket includes a trapezoidal support and a transition support. The tank is disposed on the support bracket. The support bracket is disposed in the cuboidal frame. The upper body, the first lower body, and the second lower body are spherical and communicate with each other. A filling tube, a pressure relief tube and a piezometer tube are disposed on the upper body. The first membrane is disposed on the tank. The first thermal insulation layer is coated on the first membrane.

Abstract: Provided is a performance controlling method for a high-strength aluminum alloy shell during an ultra-low temperature forming process. The present disclosure greatly improves the performance of an aluminum alloy sheet by applying an ultra-low temperature. The present disclosure cools the aluminum alloy sheet to an ultra-low temperature by using an ultra-low temperature cooling medium, so as to compensate for insufficient hardening caused by insufficient deformation and avoid cracking caused by increased deformation. The present disclosure cools the sheet blank zonally according to a deformation law of a desired curved part, and controls the ultra-low temperature distribution of the sheet blank during forming so as to promote the formation of a substructure in a small-deformation zone. In this way, the present disclosure improves a subsequent age-hardening effect, and corresponding uniformity of microstructure and performance, and effectively solves the problem of non-uniformity due to uneven deformation.

Abstract: The present disclosure provides a method for protection against fretting fatigue by compound modification via laser shock peening and coating lubrication, where a group of micro-pits distributed into a regular array is firstly formed in a surface of a metal material by using laser shock peening, with a single micro-pit having a diameter of 1 to 10 mm and a depth of 1 to 20 ?m; and the micro-pits are then coated with a lubricant by coating preparation. Based on the micro-pit styling feature and surface residual compressive stress introducing feature of the laser shock peening, with compound modification by surface texturing via the laser shock peening and coating lubrication, the surface of the material can be reinforced by residual compressive stress, coating lubrication and surface micro-pit texturing with a synergistic effect, thus allowing for improved fretting fatigue behavior of the material.

Abstract: An inertial mass amplification type tuned mass damper is disclosed. The inertial mass amplification type tuned mass damper comprises a hollow box, an H-shaped mass block, gears a, gears b, a rectangular frame, a steel ring, viscous dampers, a steel sheet, springs, rotating shafts and balls. In the present invention, an inertial damping force is amplified by adjusting the radius ratio of the gears a and the gears b; and damping parameters can be conveniently changed by adjusting the mass of the mass block, the spring stiffness and the like. The present invention has the advantages that the design mass is small, which can avoid the adverse effects of excessive additional gravity on the structure and improve the performance of the structure. The present invention has reasonable design and small occupied space, can save more use area for buildings and can greatly improve the utilization efficiency of the buildings.

Abstract: An iron-based superalloy for high temperature 700° C. with coherent precipitation of cuboidal B2 nanoparticles, belongs to the field of heat-resistant stainless steel, including Fe, Cr, Ni, Al, Mo, W, Zr, B elements. C, Si, Mn, S, P, O, N are impurity elements. The weight percent (wt. %) of its alloy composition is Cr: 10.0˜12.0, Ni: 13.0˜15.0, Al: 6.0˜7.0, Mo: 2.0˜3.0, W: 0.3˜0.7, Zr: 0.03˜0.05, B: 0.004˜0.007, C?0.02, Si?0.20, Mn?0.20, S?0.01, P?0.02, O?0.005, N?0.02, Fe: balance; and the atomic percent ratio of Zr/B is 1:1, the atomic percent ratio of Cr/(Mo+W) is 8:1, and the atomic percent ratio of Mo/W is 8:1. The coherent precipitation of cuboidal B2 nanoparticles in ferritic matrix through the alloy composition design.

Abstract: The present invention belongs to the technical field of underwater communication, and provides a novel highly robust underwater optical communication system which comprises a sending module and a receiving module. The novel highly robust underwater optical communication system realizes highly robust underwater optical communication under strong interference of sunlight and artificial light sources. The system uses a new physical method irrelevant to frequency, and can be used with existing MIMO and CDMA to obtain better communication effects. The circularly polarized light is used for signal transmission, thereby avoiding the problem of channel misalignment caused by the rotation of a platform underwater. At the same time, good polarization maintaining of a marine environment makes the signal characteristics difficult to lose.

Abstract: The present invention provides a method for estimating high-quality depth map based on depth prediction and enhancement sub-networks, belonging to the technical field of image processing and computer vision. This method constructs depth prediction subnetwork to predict depth information from color image and uses depth enhancement subnetwork to obtain high-quality depth map by recovering the low-resolution depth map. It is easy to construct the system, and can obtain the high-quality depth map from the corresponding color image directly by the well-trained end to end network. The algorithm is easy to be implemented. It uses high-frequency component of color image to help to recover the lost depth boundaries information caused by down-sampling operators in depth prediction sub-network, and finally obtains high-quality and high-resolution depth maps. It uses spatial pyramid pooling structure to increase the accuracy of depth map prediction for multi-scale objects in the scene.

Abstract: The present invention provides a method for manufacturing a curved thin-walled intermetallic compound component by winding a mandrel with metal foil strips, which comprises the following steps: designing a prefabricated blank; preparing a support mandrel; determining thicknesses and layer numbers of foil strips; determining widths of the foil strips; establishing a laying process; pretreating surfaces of the foil strips; laying A foil and B foil; carrying out bulge forming on the prefabricated blank; carrying out diffusion reaction and densification treatment on a bulged component; and carrying out subsequent treatment of a thin-walled component. The present invention can solve the problems that impurities generated in the separation process of a support mould and a laminated foil prefabricated blank influence the final performance of a part, and a single homogeneous intermetallic compound component in thickness direction has poor plasticity and toughness at room temperature.

Abstract: An eddy current energy-dissipating spacer is mainly composed of a spacer frame, a conductor clamp and energy-dissipating elements. The eddy current energy-dissipating spacer not only provides the function of an ordinary spacer, but also reduces the vibration of the transmission lines; and at the same time, can effectively reduce the vibration of the transmission lines, especially the torsional vibration by adopting the eddy current and viscoelastic material for energy dissipation; improves the eddy current strength by adjusting the gear radius ratio, thus increasing the damping force; can adjust the damping parameters by adjusting the magnetic field strength of the permanent magnet; can produce long-term stable vibration reduction effect by adopting the permanent magnet to provide continuous magnetic field without additional external energy input; can effectively avoid the magnetic flux leakage of magnetic circuits by adopting the magnetic material.

Abstract: A practical method for short-term operations of large-scale hydropower plants divides all hydropower plants into three categories using operation characteristics such as system hierarchy, space attributes, task requirements, and schedule particularity. A strategy for adjusting spillage based on peak-shaving response and a strategy for equal load reduction in off-peak hours check and adjust power generation of hydropower plants with specified dispatching modes. For medium- and small-sized cascaded hydropower plants, the load distribution among plants is optimized with an objective of minimizing total power release subject to control condition of total generation profile. For large-size cascaded hydropower plants, an optimization model for peak-shaving operations and a method for balancing power plants with equal load rate are combined to respond to system peak demands and guarantee power balance in all periods.

Abstract: The present disclosure discloses an ultrasonic cutting holder for a honeycomb core, including a holder, a swing mechanism, a transducer, a first-stage amplitude transformer, a second-stage amplitude transformer, an ultrasonic cutting tool, and an ultrasonic power transmission mechanism. The present disclosure provides an ultrasonic cutting holder for a honeycomb core with large amplitude output capacity and considering the interchangeability requirements among different vibration systems, which solves the problem of the applicability of ultrasonic cutting holder on the universal machine tool and improves the automation level of ultrasonic cutting.

Abstract: Disclosed are a universal alpha-olefin polymerization industrial catalyst, and an application thereof, specifically an industrial production catalyst which consists of (A) a solid catalyst component, (B) a cocatalyst organoaluminium compound and (C) an external electron donor compound, and is used for various alpha-olefin polymerization or copolymerization processes. The solid catalyst component (A) is prepared from a dibutyl phthalate or diisobutyl phthalate and 9,9-bis(methoxymethyl)fluorene composite internal electron donor. A hydrocarbyl alkoxy silicon, an organic acid ester or a hydrocarbyl alkoxy silicon and organic acid ester composite acts as the external electron donor component (C). The solid catalyst component (A), the cocatalyst organoaluminium compound (B) and the external electron donor compound (C) are used together in industrial devices for various alpha-olefin polymerization or copolymerization processes to produce new grades of poly-alpha-olefins.

Abstract: A method for automatically detecting the free vibration response segment of the high-speed railway bridges after trains passing. First, pre-select the test response sequence to be decomposed based on the maximum of the time instants corresponding to the absolute maximums of the response vectors at various measuring point. Then, Extract the single-frequency modal response from the test response by the iterative variational mode decomposition and fit the envelope amplitude of the modal response by Hilbert transform. Finally, the vibration features at each time instants are marked as decay vibration or non-decay vibration. The longest structural response segment that meets the decay vibration features is determined as the detected free vibration response segment for modal identification. This invention can effectively detect the free vibration data segment without human participation, which is of great significance for the real-time accurate modal analysis of high-speed railway bridges.

Abstract: The present invention provides a CT triaxial test apparatus for hydrate-bearing sediment, and belongs to the technical field of fundamental physical property measurement of geotechnical engineering. In the apparatus, aiming at the defects of the invention “a visual test apparatus for mechanical characteristics of natural gas hydrate-bearing sediment”, the CT triaxial test apparatus for hydrate-bearing sediment is redesigned and optimized, on the premise of obtaining static and dynamic mechanical characteristics and creep characteristics of a hydrate reservoir, the stability of the triaxial apparatus during rotation due to scanning, the temperature control accuracy of a hydrate-bearing sample, and the X-ray penetration performance of the pressure chamber of the triaxial apparatus are improved, an optimal CT imaging effect is obtained, and powerful hardware support is provided to ascertain the reservoir deformation mechanism during hydrate decomposition.