Zhenlong Wang’s research while affiliated with Harbin Institute of Technology and other places

Network microstructure titanium matrix composites (NMTMCs), featuring Ti6Al4V as the matrix and network-distributed TiB whiskers (TiBw) as reinforcement, exhibit remarkable potential for diverse applications due to their superior physical properties. Due to the difficulty in machining titanium matrix composites, electrical discharge machining (EDM) stands as one of the preferred machining techniques for NMTMCs. Nevertheless, the compromised surface quality and the recast layer significantly impact the performance of the workpiece machined by EDM. Therefore, for the purpose of enhancing the surface quality and restraining the defects of NMTMCs, this study conducted comparative EDM milling experiments between NMTMCs and Ti6Al4V to analyze the effects of discharge capacitance, charging current, and pulse interval on the surface roughness, recast layer thickness, recast layer uniformity, and surface microcrack density of both materials. The results indicated that machining energy significantly influences workpiece surface quality. Furthermore, comparative experiments exploring the influence of network reinforcement on EDM milling revealed that NMTMCs have a higher melting point, leading to an accumulation phenomenon in low-energy machining where the reinforcement could not be completely removed. The residual reinforcement in the recasting layer had an adsorption effect on molten metal affecting the thermal conductivity and uniformity within the recasting layer. Finally, specific guidelines are put forward for optimizing the material’s surface roughness, recast layer thickness, and uniformity, along with minimizing microcrack density, which attain a processing effect that features a roughness of Ra 0.9 μm, an average recast layer thickness of 6 μm with a range of 8 μm, and a surface microcrack density of 0.08 μm−1.

Terahertz (THZ) band stop filter can be used to filter interference signals in a filter pass band. The quality factor (Q) is the most important index to evaluate the transmission performance of filter. Usually, the high Q, the narrow bandwidth and the large slope of the stop band will promise the good filtering accuracy and transmission response. However, the Q value taken from metamaterial structures designed on the plane is always only in the single digit, resulting in less than satisfactory in filtering performance. Herein, a high Q terahertz band stop filter based on metamaterials was proposed. To fabricate this three-dimensional (3D) metamaterial structure, a microtopographic substrate guided method with feasible and high accuracy capacities was proposed. As a result, the device is measured to be in the filtering state in 1.038-1.102 THz while it is stopped in 1.062-1.066 THz. The similarity between the experimental and simulated transmission is up to 86.32%, indicating the fabricating method possesses a high accuracy. Accordingly, the Q value was calculated to be as high as 532. The band stop filter with this record Q value can be widely used in THZ detection, imaging and sensing in future. Meanwhile, the proposed fabrication method is effectively applied in 3D metamaterial and THZ device as well.

Multifunctional capability and low coupling electronic skin (e‐skin) is of great significance in advanced robot systems interacting with the human body or the external environment directly. Herein, a multifunctional e‐skin system via vertical integrated different sensing materials and structures is presented. The multifunctional e‐skin has capacity sensing the proximity, pressure, temperature, and relative humidity simultaneously, with scope of 100–0 mm, 0–30 N, 20–120 °C and 20–70%, respectively. The sensitivity of the four kinds of sensors can be achieved to 0.72 mm⁻¹, 16.34 N⁻¹, 0.0032 °C⁻¹, and 15.2 pF/%RH, respectively. The cross‐coupling errors are less than 1.96%, 1.08%, 2.65%, and 1.64%, respectively, after temperature compensation. To be state‐of‐the‐art, a commercial robot is accurately controlled via the multifunctional e‐skin system in the complicated environment. The following and safety controlling exhibit both accuracy and high dynamic features. To improve the sensing performance to the insulating objects, machine learning is employed to classify the conductivity during the object approaching, leading to set the threshold in dynamic. The accuracy for isolating the insulator increases from 18% to 88%. Looking forward, the multifunctional e‐skin system has broader applications in human–machine collaboration and industrial safety production technology.

Terahertz (THz) modulator can be used to modulate the amplitude and frequency of THz wave. A THz multiband amplitude modulator based on temperature control is proposed in this study. The metamaterial structure of proposed modulator is a double‐layer cross structure which attached on a silicon substrate, and the cross‐distribution of different materials in top and middle layer is Cu @ SiO2 and SiO2 @ VO2, respectively. To prepare the modulator, a microtopographic substrate‐guided method with low‐cost and high accuracy capacities is proposed. Finally, the proposed modulator exhibits above 70% transmittance in 1.31–1.36 THz, 1.55–1.60 THz, and 1.76–1.79 THz, respectively, at 35 °C After temperature rises to 70 °C, transmittance decreases below 0.1 in 1–2 THz. The similarity of the experimental and simulated transmission is up to 85.67%, and the mean modulation depth (MD) is 0.73. The performance can fulfill the applications in THz amplitude modulator, and due to the large modulation depth of transmission, the proposed modulator can be used as a filter switch. It also indicates the proposed method can be effectively applied in other multilayer composite materials preparation. A multiband amplitude THZ modulator based on temperature control is designed and fabricated. To prepare the modulator, a microtopographic substrate guided method with low‐cost and high accuracy capacities is proposed. The similarity of the experimental and simulated transmission is up to 85.67%, and the mean modulation depth is 0.73.

Multiinformation tactile perception is highly important for detecting the change of external environment and realizing the compliant control of the robot. However, the integration of dual‐mode or multimode sensors with low coupling remains a challenge. Herein, a dual‐function tactile sensor with linear pressure and temperature perception is reported. The pressure detection part contains the pyramid conductive film and flexible hemispherical electrode, which works as the piezoresistive material. A spiral nickel film works as a temperature‐sensitive material for sensing the temperature of objects during approaching and while contacting. As a result, the dual‐function sensor can detect the pressure in 0–100 kPa with a sensitivity of 11.5 kPa−1, while the temperature is in 25–65 °C with a sensitivity of 0.0032 °C −1. To be state of the art, the tactile sensor array is used for an active safety control of robotic arms, which can realize the perception and timely avoidance of sudden changes in external temperature and object collisions. Safety is a core concern in human–robot collaboration (HRC), and active safety control for robots has attracted widespread attention. A dual‐function tactile sensor with linear pressure and temperature perception at low degree of coupling is proposed here. The sensor array is performed to control commercial robots in HRC, which shows good perception of ambient temperature changes and object collisions.