摘要：Milling the free-end of cylindrical parts, which are vertically fixed on the machine table,often suffers from large chatter vibrations. This kind of phenomenon is harmful to the cutting process. Therefore, it is of great importance to develop means to suppress these undesirable *** paper proposes a new idea for designing a tunable mass damper(TMD) to reduce vibrations in milling of cylindrical parts. Frequency response function(FRF) of the milling system is derived to comprehensively reveal the influence of both the dynamic response of the machine tools and the TMD. Critical axial depth of cut, which is usually used to characterize the process stability, is formulated by considering the FRFs of both the milling system itself and the TMD. Maximization of critical axial depth of cut is taken as objective function, while kernel dynamic parameters of TMD,which are involved in the derived expression of critical axial depth of cut, are extracted as designable variables. Optimization procedure is carried out to adjust the parameters of TMD by using sequential quadratic programming algorithm. A series of experiments with a designed passive TMD validate that the design has a good performance in reducing vibrations and improving stability of milling process.

摘要：The metallic antenna design problem can be treated as a problem to find the optimal distribution of conductive material in a certain domain. Although this problem is well suited for topology optimization method, the volumetric distribution of conductive material based on 3D finite element method (FEM) has been known to cause numerical bottlenecks such as the skin depth issue, meshed 'air regions' and other numerical problems. In this paper a topology optimization method based on the method of moments (MoM) for configuration design of planar metallic antenna was proposed. The candidate structure of the planar metallic antenna was approximately considered as a resistance sheet with position-dependent impedance. In this way, the electromagnetic property of the antenna can be analyzed easily by using the MoM to solve the radiation problem of the resistance sheet in a finite domain. The topology of the antenna was depicted with the distribution of the impedance related to the design parameters or relative densities. The conductive material (metal) was assumed to have zero impedance, whereas the non-conductive material was simulated as a material with a finite but large enough impedance. The interpolation function of the impedance between conductive material and non-conductive material was taken as a tangential function. The design of planar metallic antenna was optimized for maximizing the efficiency at the target frequency. The results illustrated the effectiveness of the method.

摘要：With the rapid development of artificial intelligence technology and increasing material data,machine learning-and artificial intelligence-assisted design of high-performance steel materials is becoming a mainstream paradigm in materials *** learning methods,based on an interdisciplinary discipline between computer science,statistics and material science,are good at discovering correlations between numerous data *** with the traditional physical modeling method in material science,the main advantage of machine learning is that it overcomes the complex physical mechanisms of the material itself and provides a new perspective for the research and development of novel *** review starts with data preprocessing and the introduction of different machine learning models,including algorithm selection and model ***,some successful cases of applying machine learning methods in the field of steel research are reviewed based on the main theme of optimizing composition,structure,processing,and *** application of machine learning methods to the performance-oriented inverse design of material composition and detection of steel defects is also ***,the applicability and limitations of machine learning in the material field are summarized,and future directions and prospects are discussed.

摘要：A two-dimensional panel in subsonic flow with stochastic excitation is studied by assuming that the aerodynamic pressure contains random pressure *** on the global properties,the sensitivities of system parameters and noise intensities are ***,the parameter region with multiple coexisting attractors under different dynamic pressures is *** is found that the coexistence of multiple attractors extensively appears and the basin structure may be *** the periodic time history diagrams are calculated by simulating the random pressure fluctuation as Poisson white *** results show that under typical bistable conditions,the noise sensitivity of the subsonic panel system is related to the basin structures and the disposition of the coexisting attractors to the *** transition between two attractors diffuses along the unstable manifold and tends to the position where the basin boundary curvature is relatively *** findings underscore the importance of global analysis in assessing the noise load carrying capacity,which provides some valuable insights into the safety design of subsonic panel systems.

摘要：We present the design and optimization of evanescently coupled waveguide photodiodes（EC-WPDs） based on the coupling modes theory and the beam propagation *** focalization of the optical power in the absorber is achieved by an appropriate choice of index matching layers of *** simulation shows that high-speed（40 GHz）,high quantum efficiency（81%） and high linearity photodiodes can be achieved, and EC-WPDs are promising devices for future optical communication systems.

摘要：A compact common-mode filter is proposed to suppress common-mode noise for application of high-speed differential signal traces. The filter adopts one big C-shaped defected ground structure （DGS） cell in the left of ground plane and two small C-shaped DGS cells with opposite direction in the right of ground plane. Because these DGS cells have different dimensions, the filter has three adjacent equivalent resonant points, which can suppress wideband common-mode noise effectively. The left C-shaped DGS and its adjacent C-shaped DGS cell form an approximate closed structure, which can efficiently reduce the influence of the mutual capacitance. The filter provides a common-mode suppression from 3.6 GHz to 14.4 GHz over 15 dB while it has a small size of 10 minx 10 mm. The fractional bandwidth of the filter is 120%, and the differential signals still keep good signal integrity. The experimental results are in good agreement with the simulated results.

摘要：Contextual advertising is a major revenue source for today＇s companies. Keyword extraction is a key step in this kind of advertising, through which appropriate advertising keywords are extracted from Web pages so that corresponding ads can be triggered. This paper describes a system that learns how to extract keywords from web pages for advertisement targeting. Firstly a text network for a single webpage is build, then PageRank is applied in the network to decide on the importance of a word, finally top-ranked words are selected as keywords of the webpage. The algorithm is tested on the corpus ofblog pages, and the experimental results prove practical and effective.

摘要：An effective cancer nanodrug not only needs to load a large fraction of pharmaceutical molecules and release them in responsive ways, to function as imaging and photothermal agents, but also needs to possess the favorable morphologies that are favored by the EPR effect of cancer tissues. In this study, we designed a spherical nanodrug by forming clusters using DOX and a polymer-engineered rGO. These spherical nanodrugs had a diameter of around 750 nm and assumed both functionalities of chemical therapy and the photothermal effect. In addition, this nanodrug featured a high-loading capability of DOX, a pH-responsive release profile, a self-fluorescent capability, and an effective accumulation in cancer cells. The layer-by-layer assembly of three cycles of polyethylene glycol (PEG) and polyacrylic acid (PAA) around the rGO core was indispensable in achieving a chemically-modified rGO precursor that assembled with DOX to produce the spherical nanodrug. The spherical nanodrug effectively decreased cell viability upon NIR irradiations.

摘要：In this paper,a novel 2-DOF rotational pointing mechanism(RPM)is designed inspired by the guidelines of the graphical *** mechanism integrates with a fast steering mirror(FSM)for compensating pointing errors of a laser *** design intends to achieve an angular travel of±10 mrad and steers a 25 mm mirror aperture.A planar flexure with beam flexures accompanied in parallel with an axial flexure build-up mechanism *** mechanismbased RPM ensures high precision and *** characteristics are established based on the stiffness matrix method for four different planar flexure *** layout with best in-plane rotational compliance is then assessed for performance sensitivity to mechanism dimension parameters and parasitic error,thus informing the design *** stiffness in both the inplane rotational axes and stress is determined based on finite element analysis(FEA).The wire electrical discharge machining(EDM)is employed for developing the proof of concept for the RPM and is then assembled in *** are conducted to determine the rotational stiffness and angular travel about both in-plane rotational *** among theoretical,numerical and experiments reveal excellent linearity of rotational stiffness along the rotational travel *** maximum theoretical error is less than 5.5%compared with FEA while,the experimental error has a mean of 5%and 3%for both rotational axes thus satisfying the intended design requirement.

摘要：Fingers are the basic components of anthropomorphic *** present,most anthropomorphic fingers utilize rigid joints,which have obvious fabrication and assembly complexities as well as limited flexibility and ***,some anthropomorphic fingers were attempted to utilize compliant joints learned from bioinspiration,but they have a limited self-resetting ability and lateral deformation resistance,as well as occupying a large space and having a non-anthropomorphic *** this paper,nine compliant joints for anthropomorphic fingers were analyzed using Finite Element Analysis(FEA),based on which two combined compliant joints were proposed,and the optimal one was obtained through FEA and *** anthropomorphic finger that embeds parts of the compliant joint into the adjacent phalanxes was then ***,the anthropomorphic finger was fabricated and experiments were *** results show that the anthropomorphic finger with the proposed combined compliant joints has a better self-resetting ability and lateral deformation resistance while ensuring a large range of motion similar to that of the human finger,and the required actuating force is ***,the embedded joint structure can reduce the occupied space of the joint so as to improve the anthropomorphic appearance of the finger,and enhance its lateral deformation resistance.