Search

Laser metal deposition (LMD) is a technology for the production of near-net-shape components. It is necessary to control the manufacturing process to obtain good geometrical accuracy and metallurgical properties. In the present study, a closed-loop control method of melt pool temperature for the deposition of small Ti6Al4V blocks in open environment was proposed. Based on the developed melt pool temperature sensor and deposition height sensor, a closed-loop control system and proportional-integral (PI) controller were developed and tested. The results show that with a PI temperature controller, the melt pool temperature tends to the desired value and remains stable. Compared to the deposition block without the controller, a flatter surface and no oxidation phenomenon are obtained with the controller. [ABSTRACT FROM AUTHOR]

The Kuroshio Loop Current (KLC) is an important form of Kuroshio intrusion into the northeastern South China Sea (NESCS), which has significant influences on dynamical and biogeochemical processes in the NESCS. Recent studies suggested that the KLC is a hot spot of submesoscale processes (submesoscales) with spatiotemporal scales of O(1–10) km and O(1–10) days, but submesoscales' roles in energy cascade and salt and heat transports remain obscure. Here, we investigate this issue through analyzing outputs from a 1/48° simulation. The kinetic energy exchange rate between submesoscale and larger‐scale processes (KER) is overall positive in the KLC region, which suggests the dominance of forward cascade. The magnitude of KER is comparable with the temporal change rate of larger‐scale kinetic energy in the upper 200 m. We also find that magnitude and direction of KER are closely associated with strain rate and horizontal divergence of background flows, respectively. In addition, the KLC region shows elevated submesoscale salinity and heat diffusivities with magnitudes reaching O(102) m2 s−1. During the KLC period, horizontal mixing by submesoscales can transport 0.90 × 1013 kg salt and 0.71 × 1020 J heat westward into the NESCS interior, which are an order of magnitude larger than those caused by the mesoscale eddy shedding from the KLC. These results suggest that submesoscales play important roles not only in energy cascade but also in salt and heat transports in the KLC region. Therefore, the roles of submesoscales should be taken into account when studying energy, salt, and heat budgets in the NESCS. Plain Language Summary: As the western boundary current of the North Pacific subtropical gyre, the Kuroshio can intrude into the northeastern South China Sea (NESCS) in the form of Kuroshio Loop Current (KLC), which modulate the tracer and energy budgets of NESCS through shedding eddies. Although previous studies have reported that the KLC region is abundant with submesoscale processes (submesoscales) with spatiotemporal scales of O(1–10) km and O(1–10) days, their roles in cross‐scale energy transfer and salt and heat transports are poorly known. Here, the above issues are examined through an analysis of outputs from a 1/48° ocean simulation. We find that larger‐scale processes generally feed submesoscales through a forward energy transfer in upper 200 m, whose rate is comparable in magnitude with the temporal change rate of larger‐scale kinetic energy. Furthermore, the horizontal mixing effect of submesoscales can transport a huge amount of heat and salt westward into the NESCS interior during the KLC period. The salt and heat transports are an order of magnitude larger than those caused by the mesoscale eddy shedding from the KLC. The above results suggest that submesoscales associated with the KLC play important roles in the energy, heat, and salt budgets in the NESCS. Key Points: Submesoscales in the Kuroshio Loop Current (KLC) are examined using high‐resolution simulation outputsEnergy exchange between submesoscales and KLC plays an important role in the local energy budgetHorizontal salt and heat transports by submesoscales are much larger than those by mesoscale eddy shedding from the KLC [ABSTRACT FROM AUTHOR]

A photosensitive TFT sensor called bias TFT fabricated using simple amorphous silicon process in this paper. The photosensitive current of bias TFT is linearly related to the brightness of the top light source and inversely proportional to the size of the bias region. The photosensitivity current can be up to 10E‐8 amperes under 100 nits illumination. Among four shapes of bias TFTs, L‐type TFTs have the highest photo current. [ABSTRACT FROM AUTHOR]

We propose a broadband noise test method (10 Hz–1 MHz) using a direct power method to measure the excess noise of InGaAs/InP avalanche photodiodes (APDs) with a separate absorption, grading, charge, and multiplication structure. By this means, the impact ionization coefficient ratio (the k value) can be accurately determined. Compared with previous studies, this method can distinguish between low-frequency noise and excess noise, so for an appropriate high frequency spectral range, the excess noise can be analyzed without mixing in other noise information. Three different APDs fabricated in-house with different diameters (12, 25, and 60 µm) were investigated using the above-mentioned method under temperatures varying from −10 to −40 °C. Our findings showed that the k value of the APDs decreased as the temperature decreased. When the temperature decreased to −40 °C, the k value of the 12, 25, and 60 µm diameter diodes was as low as 0.1, 0.3, and 0.2, respectively. The measurement results are consistent with our device design and not only provide useful information for the future selection of device materials and structures but also demonstrate the feasibility of the broadband noise measurement method in the accurate determination of the k value. It indicates that low excess noise can be achieved by utilizing the temperature dependence of k. [ABSTRACT FROM AUTHOR]