- 标题
- 摘要
- 关键词
- 实验方案
- 产品
过滤筛选
- 2019
- 2018
- 2015
- low-temperature electronics
- junction field-effect transistors
- Bessel Function
- Coupling Coefficient
- Fusion temperature and Elongation speed
- Infrared Thermography
- Statistical Analysis
- Mean Temperature Difference
- Surface temperature distribution
- Diabetic Foot Complications
- Optoelectronic Information Science and Engineering
- Electronic Science and Technology
- Physics
- Don State Technical University
- China Jiliang University
- UIN Suska Riau
- BMS College of Engineering
- Dalhousie University
- Majmaah University
- Soochow University
- University of Riau
- Karnataka Institute of Endocrinology and Research (KIER)
- Southern Federal University
-
Inconel625/316L functionally graded material using spectral diagnostics during laser additive manufacturing process
摘要： In this paper, the composition of Inconel625/316L functionally graded material during the additive manufacturing process was monitored on-line by laser-induced plasma optical emission spectroscopy. Several spectral lines are used to establish the quantitative relationship between relative intensity, relative intensity ratio, plasma temperature, and functional gradient material composition variation. It is shown that the change between relative strength and compositional content is similar to actual expectations. But, the relationship between the relative intensity with Inconel625 content is nonlinear. Cr-I/Ni-I relative intensity ratios almost linearly decrease with increasing Inconel625 content. The linear correlation coe?cient of the best ?tted curve was 0.943, and the maximum percentage error was 7.5%. The plasma temperature was obtained by the Boltzmann plot using ?ve neutral chrome lines between 330 and 380 nm. Plasma temperature almost linearly increases with increasing Inconel625 content in a range. The linear correlation coe?cient of the plasma temperature ?tted straight line was 0.93, and the maximum percentage error was 2.7%. The feasibility of composition monitoring of gradient materials by spectral information during the additive manufacturing process was veri?ed.
关键词： plasma temperature,spectral diagnosis,laser additive manufacturing,composition monitoring
更新于2025-11-28 14:24:20
-
High Temperature Oxidation and Wear Resistance of In Situ Synthesized (Ti3Al?+?TiB)/Ti Composites by Laser Cladding
摘要： (Ti3Al + TiB)/Ti composites were prepared on Ti6Al4V by laser cladding. The microstructures of the coatings were analyzed; the high temperature wear and oxidation properties of the coatings were investigated and compared with Ti6Al4V. Ti3Al and TiB particles were in situ formed through the reaction between Ti and AlB2. The reinforcements exhibited some crystallographic orientation relationships with a-Ti matrix, and a semi-coherent interface (Ti3Al) or a coherent interface (TiB) was obtained. The weight gain of the coating under each combination of temperature and time condition was 20 to 30 pct of the value of Ti6Al4V under the same experimental parameters. A denser and well-bonded TiO2 + Al2O3 layer was formed, effectively hindering the oxygen diffusion compared with the TiO2 layer on Ti6Al4V. EBSD result showed that the Al2O3 mainly assembled into clusters and located close to the interface while the outer area of the oxidation layer was mainly TiO2. The friction coefficients and wear losses of the coatings were lower than those of the substrates at 300 °C to 750 °C. The oxidation was a crucial factor affecting the wear performance at high temperatures. The protective effect of the TiO2 + Al2O3 layer and the formation of transfer films on the worn surface contributed to the improved wear resistance of the coating.
关键词： TiB,Laser Cladding,Wear Resistance,Ti Composites,In Situ Synthesized,High Temperature Oxidation,Ti3Al
更新于2025-11-28 14:24:20
-
Hyperspectral and thermal temperature estimation during laser cladding
摘要： Although there is no doubt about the tremendous industrial potential of metal additive manufacturing techniques such as laser metal deposition, the technology still has some intrinsic quality challenges to overcome before reaching its industrial maturity. Noncontact in situ monitoring of the temperature evolution of the workpiece could provide the necessary information to implement an automated closed-loop process control system and optimize the manufacturing process, providing a robust solution to these issues. However, measuring absolute temperatures is not self-evident: wavelength-dependent emissivity values vary between solid, liquid, and mushy metallic regions, requiring spectral information and dedicated postprocessing to relate the amount of emitted infrared radiation to the material temperature. This paper compares the temperature estimation results obtained from a visible and near-infrared hyperspectral line camera and a conventional short-wave infrared (SWIR) thermal camera during the laser melting and cladding of a 316L steel sample. Both methods show agreeing results for the temperature distribution inside the melt pool, with the SWIR camera extending the temperature measurements beyond the melt pool boundaries into the solid region.
关键词： temperature estimation,laser cladding,hyperspectral imaging,additive manufacturing,thermal monitoring
更新于2025-11-28 14:24:20
-
Effects of phase transition temperature and preheating on residual stress in multi-pass & multi-layer laser metal deposition
摘要： To investigate the influences of phase transition temperature and preheating on the residual stress of multi-layer and multi-pass laser metal deposition (LMD), the multi-layer and multi-pass LMD, with and without preheating, were performed using five kinds of alloy with different phase transition features, and their residual stresses were measured using the hole drilling method. A finite-element (FE) model incorporating the phase transition was developed based on experimentally obtained physical property data. The results demonstrated that the low-temperature solid phase transition has a tensile stress relaxation effect, which leads to the formation of a compressive stress area. This relaxation effect was observed to decrease with the increase of the phase transition temperature. The high-temperature solid phase transition has no significant tensile stress relaxation effect during the multi-layer and multi-pass LMD process, which is different from the single track LMD. when the solid phase transition temperature is low, the preheating can improve the uniformity of the stress field only to a certain extent. However, when the preheating increases the lowest temperature of the thermal cycle and makes it higher than the starting point temperature of the solid phase transition, the tensile stress relaxation effect of the solid phase transition can be brought into full play.
关键词： Finite element analysis,Preheating,phase transition temperature,Residual stress,Laser metal deposition
更新于2025-11-28 14:24:20
-
High temperature wear performance of laser cladding Co06 coating on high-speed train brake disc
摘要： Abnormal wear sometimes occurs on the high speed train brake disc surface in winter time. In this paper, Co-based alloy powders were deposited by laser cladding technology to improve the wear resistance of train brake discs. Sliding wear at room temperature, 200℃, 400℃ and 600℃ were conducted to investigate the wear behavior. Microstructure, hardness, and phase composition of Co06 cladding layers were also studied. The results showed that Co06 cladding layer exhibited better wear resistance than the substrate, with different wear mechanisms at high temperatures. Co06 cladding layers also exhibited better high temperature oxidation resistance than the substrate. Cr23C6 played a significant role in anti-friction.
关键词： high temperature wear behavior,laser cladding,high speed train,brake disc
更新于2025-11-28 14:24:20
-
Multi-parameter sensor based on single Long Period Grating in Panda fiber for the simultaneous measurement of SRI, temperature and strain
摘要： In this work, a three-parameter sensor for the simultaneous measurement of surrounding refractive index (SRI), temperature and strain is presented. It is based on a single Long Period Grating (LPG) written in a polarization-maintaining Panda fiber, by means of a simple technique based on Electric Arc Discharge. For the purpose, it is performed the monitoring of the wavelength shift of three different resonances, each one associated to a different cladding mode. Moreover, the set of resonances is acquired for two polarizations of the input light, i.e. aligned to the slow and fast axis of the fiber. The three-parameter sensing is promoted by the fact that the resonance dips show different sensitivities to SRI, temperature and strain, which change their magnitudes and signs when the polarization is switched. It was demonstrated that the sensor can be applied to simultaneously measure SRI in range 1.33–1.40, temperatures comprised in 20–60 °C, and strain of hundreds of με. This device could find application in the fields of materials science and structural health monitoring.
关键词： Refractive index sensor,Temperature sensor,Fiber grating sensor,Strain sensor,Multi-parametric sensor,Long period grating
更新于2025-11-28 14:24:03
-
Passively Q-switched fiber laser tunable by Sagnac interferometer operation
摘要： In this paper, a stable passively Q-switched Erbium-doped fiber laser (EDFL) tunable by Sagnac interferometer operation was described by using a graphene oxide saturable absorber (SA) as a Q-switcher. The wavelength operation of the Q-switched EDFL was tunable from 1566.3 nm to 1559.3 nm by increasing the temperature of sagnac loop mirror (SLM) from 30 °C to 70 °C in the figure-of-eight laser configuration. At 1566.3 nm operation, by increasing the pump from the threshold power of 77.3 mW to 126.5 mW, the repetition rate can be increased from 30.7 kHz to 41.5 kHz while the pulse width was narrowed from 10.2 to 7.3 μs. The Q-switching threshold pump power increased with the increase of the temperature, which then shifted the operation to a shorter wavelength. However, the laser efficiency increased at a shorter wavelength operation. At 1561.4 nm operation, the maximum pulse energy of 20.5 nJ was obtained at 161.0 mW pump power.
关键词： Q-switching operation,Fiber lasers,Sagnac loop mirror,Temperature tuning
更新于2025-11-28 14:24:03
-
Stable and compact nanosecond pulse seed source with diode laser driven by a high-speed circuit and a temperature control circuit
摘要： We demonstrated a nanosecond pulse seed source with a diode laser (DL) of 1550 nm A short pulse generator and a short pulse driver came to form a high-speed circuit that drove the seed source. A temperature control circuit was employed to control the stability of the laser pulses. The experimental results provided that continuously adjustable 5 kHz to 25 MHz repetition frequency and 3.5 ns to 51 ns pulse duration were acquired. The ?ne tuning of pulse duration of seed signals was realized by adjusting the current of the laser in its operating current range. Stability of the output power over two hours was 0.13% at repetition frequency of 25 MHz and pulse duration of 3.5 ns, respectively.
关键词： Short pulse generator,Temperature control,Short pulse driver,Pulse seed source,Nanosecond pulse
更新于2025-11-28 14:24:03
-
Study on a high-temperature optical fiber F–P acceleration sensing system based on MEMS
摘要： Vibration measurement at high temperature is of great signi?cance to monitoring the operation of major projects and mechanical equipment. As the temperature resistance of electrical vibration sensors is usually below 600 °C, it cannot meet the requirements of some high-temperature measuring conditions. This paper studies a high-temperature Fabry–Perot (F–P) acceleration sensing system with general single-mode ?ber. A high-temperature sensitive diaphragm is machined based on micro-electromechanical system (MEMS) technology and it is combined with the ?ber microstructure to enable the sensing probe to be packaged under high temperatures. According to the temperature characteristic of the length of the F–P cavity, a signal demodulation system was proposed based on the rapid automatic tracking of the quiescent operation point. The complete optical ?ber F–P acceleration sensing system conducted real-time vibration detection of high temperature casting in the foundry factory. The experimental result indicates that the optical ?ber high-temperature acceleration sensor showed a better vibration response in the working frequency of 100–1000 Hz and the relative error of the frequency measurement is less than 1.56% under normal temperatures and a high temperature of 800 °C.
关键词： Optical ?ber F–P,High-temperature,Acceleration sensor,Tunable laser source,MEMS
更新于2025-11-28 14:23:57
-
On-line Writing of Fiber Bragg Grating Array on a Two-mode Optical Fiber for Sensing Applications
摘要： On-line fabricated fiber Bragg grating (FBG) array and its sensing potentials have attracted plenty of attention in recent years. In this paper, FBG arrays are written on-line on a two-mode fiber, and this two-mode fiber Bragg grating (TM-FBG) is further experimentally investigated for temperature and curvature sensing. The responses of this sensor were characterized by 11.2 pm/°C for temperature and ?0.21 dB/m?1 for curvature, respectively. Based on the measurements, a dual-parameter fiber sensing system was developed, which can realize the quasi-distributed, simultaneous detection of temperature and curvature, making it suitable for structural health monitoring or perimeter security.
关键词： on-line grating writing,fiber Bragg grating,two-mode fiber,curvature sensing,temperature sensing
更新于2025-11-28 14:23:57