High Frequency Induction Research Articles

Direct Shoot Organogenesis from Nodal Explants of Sphaeranthus indicus: A Pathway for Micropropagation and Cultivation of Multipotential Medicinal Plant

Sphaeranthus indicus is an important medicinal plant, widely used in traditional medicine for its therapeutic potential, particularly its antiviral, antimicrobial, anti-inflammatory and anticancer activities. Despite its medicinal importance, there is a need for developing efficient propagation methods to ensure its large-scale cultivation and conservation. This study aims to develop a protocol direct shoot organogenesis from nodal explants of Sphaeranthus indicus. In vitro regeneration through direct shoot organogenesis offers an efficient method for the propagation of medicinally valuable plants. Explants were subjected to surface sterilization followed by culture on MS medium (Murashige and Skoog medium) supplemented with different concentrations of BAP (6-Benzylaminopurine) for shoot induction. Root initiation was achieved on MS medium with α-naphthaleneacetic acid (NAA), and regenerated plantlets were successfully acclimatized and shifted to greenhouse and open field conditions. High shoot induction frequency of 91.6% with the lowest concentration of 1 mg/L BAP highlights the efficient regeneration protocol and initiate a pathway for micropropagation and cultivation of multipotential medicinal plant, S. indicus in large-scale. During the present investigation, an efficient in vitro regeneration protocol is developed

Mechanisms of Hardness Variation in 14Cr12Ni3Mo2VN Martensitic Stainless Steel Under Different Tempering Temperatures Following High-Frequency Induction Quenching

Mechanisms of Hardness Variation in 14Cr12Ni3Mo2VN Martensitic Stainless Steel Under Different Tempering Temperatures Following High-Frequency Induction Quenching

Numerical calculation of high frequency induction heating for complex hull plate considering deflection

Numerical calculation of high frequency induction heating for complex hull plate considering deflection

Compact dual-band patch rectennas impedance matching circuit eliminated for wireless energy harvesting

ABSTRACT In this paper, a dual band patch rectenna without matching network is proposed. The proposed rectenna consists of a conventional rectangular microstrip antenna, Schottky diode, a low-pass filter, and a DC load. The function of the low-pass filter is realized by a high frequency inductor and capacitor. The input impedance of the rectangular microstrip antenna is conjugately matched to the input impedance of the rectifier by adjusting the antenna dimensions as well as the position of the feed at both 1.75 GHz and 2.45 GHz. The rectenna is fabricated as well as measured after simulation. The maximum conversion efficiency is 61% at 1.75 GHz and 72% at 2.45 GHz, with input power of 0 dBm at a load of 150 Ω . The measured results confirm the high efficiency of the rectenna. The proposed rectenna has the advantages of small size, high efficiency, multi-frequency, saving matching network and easy fabrication. The method designed in this paper can be generalized to multiple bands such as tri-band, quad-band and other forms of patch rectenna.

Iterative Semi-auto-labeling Method for High-Frequency Induction Brazing

Iterative Semi-auto-labeling Method for High-Frequency Induction Brazing

Iron Oxide Scale Formation Mechanism and Anti-Corrosion Technology from Induction Remelting of Boiler Coating in Waste Incineration Power Plant.

High-frequency induction welding technology represents the development direction of the high-temperature corrosion protection technology for the heating surfaces of the boiler "four tubes". However, when the high-frequency induction coil heats and remelts the coating on the tube's outer wall, the tube's inner wall is also heated, causing an iron oxide scale to form on the tube's inner wall. When the remelting temperature rises and the temperature of the tube's inner wall exceeds 580 °C, three layers of oxide films, FeO, Fe3O4, and Fe2O3 are arranged in sequence from the substrate surface of the tube's inner wall to the outside, with a thickness ratio of approximately 1:10:100. From the XRD spectra of tube iron oxide scale, it can be seen that the oxidation of the tube. The skin is mainly composed of Fe3O4, with a certain amount of Fe2O3 and trace amounts of FeO. The iron in the diffraction peak originates from the metal matrix. However, when the remelting temperature continues to rise and the temperature of the tube's inner wall exceeds 580 °C, the oxide film begins to thicken significantly, that is, the oxide film begins to transform into an oxide scale. Under the continuous action of high-temperature induction remelting, the reaction between iron and oxygen is accelerated, but because the oxygen ions of water slowly diffuse through two outer layers of oxide films, with a low oxygen concentration. Although the FeO film is thin, it has a loose structure and numerous lattice defects, is unstable and easy to decompose, and easily peels off from the tube's inner wall. For a pipe wall thickness of 5 mm, if the thinning rate of the inner wall caused by detachment reaches 0.8 mm/year, it is highly likely to cause pipe burst accidents within 4-5 years. The influence of the iron oxide scale on the performance of the tube's inner wall was evaluated by testing indexes, such as surface hardness and decarburization layer depth. Although the oxide scale reduces the surface hardness of the tube's inner wall, the surface decarburization layer is very thin, so the effect on the mechanical properties of the tube's substrate is limited. The technology of inhibiting the formation of the iron oxide scale in induction remelting is briefly introduced. During the high-frequency remelting process of water-cooled walls, as the tube bank moves forward relative to the high-frequency heating coil, nitrogen protection is used to suppress the formation of oxide scale, effectively eliminating the troubles caused by high-frequency induction remelting and achieving the goal of improving the service life of the tube bank. This technology of the nitrogen protection method is used to inhibit the formation of iron oxide scale, not only inhibiting the formation of the iron oxide scale on the tube inner wall and the back of the tube bundle, with remarkable experimental results and broad application prospects.

Hot Bending–Quenching Characteristics of Heat Treatable A6063 Aluminum Tubes

This study investigates the application of hot bending–quenching technology to heat-treatable A6063 aluminum tubes, focusing on the bending formability and mechanical properties after aging treatment under various heating conditions. High-frequency induction heating was used to uniformly heat aluminum tubes to the solution treatment temperature of 560 °C. The effect of wall thickness on bending formability was explored, revealing that thinner tubes (2 mm) experienced significant flattening defects, whereas thicker tubes (5 mm) exhibited superior formability with reduced shrinkage and wall thinning. Additionally, the pre-quenching temperature was found to influence the mechanical properties of the tube with a thickness of 5 mm. Tubes held at the solution temperature for 1 min 30 s or longer maintained higher temperatures during transfer, resulting in improved tensile strength and hardness after aging. The findings confirm the feasibility of applying hot bending–quenching technology to aluminum tubes, though careful control of temperature loss during continuous industrial processes is required to ensure optimal mechanical performance.

Study on Microstructure and Corrosion Fatigue Resistance of 14Cr12Ni3Mo2VN Materials Based on the Composite Technology of High-Frequency Induction Quenching and Laser Shock Peening

This study investigated the microstructure, microhardness, and residual compressive stress of 14Cr12Ni3Mo2VN martensitic stainless steel treated with high-frequency induction quenching (HFIQ) and laser shock peening (LSP). Using rotating bending corrosion fatigue testing, the corrosion fatigue performance was analyzed. Results show that a microstructural gradient formed after HFIQ and LSP: the surface layer consisted of nanocrystals, the subsurface layer of short lath martensite, and the core of thick lath martensite. A hardness gradient was introduced, with surface hardness reaching 524 Hv0.1, 163 Hv0.1 higher than the core hardness. A residual compressive stress field was introduced near the surface, with a maximum residual compressive stress of approximately −575 MPa at a depth of 0.1 mm. Corrosion fatigue results indicate that cycle loading times of samples treated with HFIQ and LSP were 2.88, 2.04, and 1.45 times higher than untreated, HFIQ-only, and LSP-only samples, respectively. Transmission electron microscopy (TEM) characterization showed that HFIQ reduced the lath martensite size, while the ultra-high strain rate induced by LSP likely caused dynamic recrystallization, forming numerous sub-boundaries and refining grains, which increased surface hardness. The plastic strain induced by LSP introduced residual compressive stress, counteracting tensile stress and hindering the initiation and propagation of corrosion fatigue cracks.

A Novel LCLC Parallel Resonant Circuit for High-Frequency Induction Heating Application

The application of induction heating power supply in the continuous production line of tinplate has garnered significant research and scholarly attention. However, the impedance matching of LC or CLC resonant circuits in the system lacks flexibility and is susceptible to overvoltage during startup. As a solution to the problem, a novel four-order LCLC parallel resonant circuit was proposed in this study for high-frequency induction heating power supply. By incorporating auxiliary inductors in parallel with CLC compensating capacitor branches, the induction heating system can operate reliably and achieve optimal load impedance matching. The equivalent circuit and mathematical model of the new resonant load were established, and the frequency characteristics of the circuit system were analyzed. Then, the parallel resonance characteristics of the new resonant circuit were comprehensively elucidated, including the quality factor, impedance characteristics, behavior of resonant current, and properties of voltage regulation. Finally, a simulation model of a high-frequency induction heating power supply was developed based on the proposed LCLC resonant circuit and compared with LC and CLC resonant circuits. The results demonstrated that the induction heating power supply system utilizing the proposed LCLC parallel resonant load exhibits superior parallel resonant characteristics, enhanced load impedance-matching flexibility, and improved output voltage stability when compared to traditional LC or CLC parallel resonant loads.

Two-Dimensional Thomson Model of a High-Frequency Induction Discharge of Finite Length

Two-Dimensional Thomson Model of a High-Frequency Induction Discharge of Finite Length

Microstructure and mechanical properties of thin-walled TA1 titanium pipes fabricated by high-frequency induction welding

Microstructure and mechanical properties of thin-walled TA1 titanium pipes fabricated by high-frequency induction welding

Design of Phase-Shifted Full Bridge Inverter for an High-Frequency Induction Heating System

<p>本文旨在發展應用於感應加熱系統之相移全橋換流電路，本文所提電路使用串聯諧振配合負載線圈電壓、電流相位控制迴路，能在負載溫度控制過程，克服感應熱負載阻抗特性變化，達到換流電路零電壓切換，同時使得負載之工作溫度得穩定在設定值。本文除理論分析外，所提方法已於實驗室完成雛形電路進行驗證，由實驗證實雛形電路500W轉換效率93.4%、160℃溫度控制誤差4.3℃，相關實驗結果顯示所提方法在感應加熱系統之應用確具可行性與實用參考價值。</p> <p> </p><p>This paper aims to develop an inverter circuit for induction heating. The proposed phase-shifted full bridge inverter utilizes series resonance to provide zero-voltage switching (ZVS) for the switching devices. By studying the voltage and current of resonance circuit along with relationships between load impedance and frequency, the working frequency and resonant current phase in the circuit can be well controlled for ZVS. Moreover, the paper has developed the temperature control loop, where software simulations and experimental measurement are both made to evaluate. Results from simulations and hardware testing is compared with each other, thereby verifying the concepts introduced in this paper.</p> <p> </p>

Induction assisted autogenous plasma arc welding of HSLA steel

Induction assisted autogenous plasma arc welding of HSLA steel

Study of cracks in the last-stage rotor blade of a steam turbine and the corrosion fatigue properties of its materials

Study of cracks in the last-stage rotor blade of a steam turbine and the corrosion fatigue properties of its materials

Finite Element Analysis in The Investigation of Methods to Model AC Resistance in A Coated Conductor

In our electricity dependent and rapidly automated society, the manipulation and usage of electricity to transmit energy is of significant prevalence. In particular, the application of current in high frequency transformers, inductors and motor generators presents a unique efficiency problem: The loss of energy through the spiking of effective resistance intrinsically related to the skin and proximity effects of an AC current. By the usage of Finite Element Analysis (FEA) in the simulative investigation of various variables on AC resistance, this paper seeks to provide insights into how coated conductors might offer advantages over the standard conductor in certain conditions, thus guiding future design and application in high-efficiency electronics. The papers findings reveal that adding a layer of coating with a lower conductivity than the core material could offer reduced energy losses up to the point when the skin depth matches the coating’s thickness. Moreover, the study explored the influence of the coating’s conductivity, suggesting that an increased conductivity of the coating material could further minimize copper losses, albeit with the trade-off of potentially higher costs. The study concludes with a Taylor Series approximation of the relationship between AC resistance and frequency using simulative data.

Synthesis of CrMnFeCoNiAlx Alloy by Mechanical Alloying and Sintering by High-Frequency Induction

Synthesis of CrMnFeCoNiAlx Alloy by Mechanical Alloying and Sintering by High-Frequency Induction

Preparation of Al-Li-Cu-Graphite Composite via High-Energy Ball Milling and Sintering with High-Frequency Induction Heating

Preparation of Al-Li-Cu-Graphite Composite via High-Energy Ball Milling and Sintering with High-Frequency Induction Heating

Joining Behaviour of Thick Plate Using High-Frequency Induction Assisted Arc Welding

Combining a preheating source with conventional arc welding is a promising method to study the weld quality and improvement of strength for high-strength super-alloy materials. The present research used an induction preheating source with plasma arc welding (PAW) to weld Inconel 625 thick plates. The investigation was performed at a constant induction current of 600 A, welding speed of 100 mm/min and a plasma welding current of 135 A. The induction-assisted plasma arc welding (IAPAW) demonstrated that a weld joint was possible with static induction preheating and a high plasma welding current at low welding speed. The microstructural observation showed various dendritic structures in the fusion zone (FZ). The FESEM and EDX analysis confirmed the formation of Laves phase in the interdendritic structure of the FZ. The ultimate tensile strength of the IAPAW joint reached to 658 MPa. The tensile fracture surface of the welded sample revealed a lower number of dimples, indicating the reduction of ductility. The XRD analysis was carried out at various zones and it confirmed the peak shifting towards the higher 2-theta value of the FZ.

Non-invasive rotor temperature detection of magnetically levitated turbo molecular pump based on high-frequency inductance

Non-invasive rotor temperature detection of magnetically levitated turbo molecular pump based on high-frequency inductance

A Fast Method of High-Frequency Induction Cladding Copper Alloy on Inner-Wall of Cylinder Based on Simulation and Experimental Study

To quickly repair the inner-surface damage to the hydraulic support cylinder caused by frequent scratches, corrosion, and wear in the process of fully mechanized coal mining, this paper proposes a method of high-frequency induction cladding (HIC) copper alloy on inner-wall of cylinder (IWC) to improve the corrosion, sealing and pressure retention performance of hydraulic cylinders combined with numerical simulation and experimental study. Firstly, a numerical temperature field model for HIC of copper alloy on the IWC is established to investigate various distribution patterns and influencing factors including frequency of induction heating, gap between coil and cladding, power supply rating, cladding thickness and side length of square section of induction coil, etc. Subsequently, an HIC test experiment is conducted to rigorously validate the numerical temperature field model and the experiment employs a meticulously collected dataset of temperature measurements, confirming the model’s accuracy and consistent alignment with anticipated changing trends. In addition, the experiment results were verified through microstructure observation, microhardness testing, friction-wear testing, and electrochemical corrosion parameters, which shows that the factors of induction heating frequency and others have obvious effects on the temperature field distribution of HIC copper alloy on the IWC. Under these working conditions (cladding thickness 1.5 mm, power supply rating 120 kW, heating frequency 120 kHz, gap between the cylindrical workpiece and the induction coil 3 mm, induction coil cross-sectional side length of 10 mm), the thermal impact on the cylinder barrel matrix is minimal, the metallurgical bonding between the cladding layer and the matrix is good, and there are no over burning and porosity defects.