Abstract Microwave surface-wave plasma (SWP) provides relatively higher ion density and radical species density than RF plasma, making it a promising plasma source for semiconductor fabrication. ...However, its plasma uniformity is compromised due to the non-uniform field distribution as the microwave wavelength is typically shorter than chamber dimensions. This could be a bottleneck as the practical application of SWP in semiconductor fabrication demands a large-area plasma with a high uniformity. In this work, we propose field agitation by applying the phase difference of 0° and 180° between the two input microwaves in the chamber to enhance the plasma uniformity. The chamber, optimized for the TM 130 mode at 2.458 GHz, successfully produces a large-area SWP with a diameter of 450 mm under 800 W absorption power and 200 mTorr argon pressure. The measurement results show that the system is capable of yielding enhanced uniformity of large-area SWP while maintaining high ion density.
•The stripe domain pattern behavior under a hard-axis perturbation.•A single universal curve as a function of the hard-axis magnetic fields.•Based on universal curve, the DMI energy and the domain ...wall type can be known.
We establish a model for a stripe domain pattern width change under hard-axis magnetic fields in a perpendicularly magnetized system with Dzyaloshinskii–Moriya interaction. With the presence of hard-axis magnetic fields, tilted magnetizations in domains modulate an exchange interaction, a perpendicular magnetic anisotropy and a dipole–dipole interaction into specific forms, which are the main competing interactions to determine the specific form of the stripe domain. In addition, we found that the stripe domain pattern change under a hard-axis perturbation can be analyzed by only considering the amount of magnetization tilting from the initial easy-axis. The proposed model was used to draw a single universal curve for stripe width change as a function of the hard-axis magnetic fields.
Steam generation by eco-friendly solar energy has immense potential in terms of low-cost power generation, desalination, sanitization, and wastewater treatment. Herein, highly efficient steam ...generation in a bilayer solar steam generator (BSSG) is demonstrated, which is comprised of a large-area SnSe–SnSe2 layer deposited on a glassy carbon foam (CF). Both CF and SnSe–SnSe2 possess high photothermal conversion capabilities and low thermal conductivities. The combined bilayer system cumulatively converts input solar light into heat through phonon-assisted transitions in the indirect band gap SnSe–SnSe2 layer, together with trapping of sunlight via multiple scattering due to the porous morphology of the CF. This synergistic effect leads to efficient broadband solar absorption. Moreover, the low out-of-plane thermal conductivities of SnSe–SnSe2 and CF confine the generated heat at the evaporation surface, resulting in a significant reduction of heat losses. Additionally, the hydrophilic nature of the acid-treated CF offers effective water transport via capillary action, required for efficient solar steam generation in a floating form. A high evaporation rate (1.28 kg m–2 h–1) and efficiency (84.1%) are acquired under 1 sun irradiation. The BSSG system shows high recyclability, stability, and durability under repeated steam-generation cycles, which renders its practical device applications possible.
Skin cancer usually occurs in the facial area relatively exposed to sunlight. Medical imaging can confirm the invasiveness and metastasis of skin cancer, which is used to establish a surgical plan. ...However, there is no method of directly marking this information on the patient's skin in the operating room. We evaluated a skin cancer resection guide that marks resection areas including safety margins on the patient's skin based on medical images and in-vitro phantom fabricated via 3D printing. The in-vitro phantom, which includes the skull, skin, and five different cancer locations was designed and fabricated based on a CT image of a patient. Skin cancer resection guides were designed using a CT image of an in-vitro phantom, with a safety margin, and four injection points at each cancer. The guide was used to insert 16 cc intravenous catheters into each cancer of the phantom, which was rescanned by CT. The catheter insertion point and angle were evaluated. The accuracy of the insertion points was 2.09 ± 1.06 mm and cosine similarities was 0.980 ± 0.020. In conclusion, skin cancer resection guides were fabricated to mark surgical plans on the patient's skin in the operating room. They demonstrated reasonable accuracies in actual clinical settings.
Abstract
Magnetic skyrmions, which are topological swirling spin textures, have drawn much attention in spintronics because of their use as an information carrier with distinct robustness rooted in ...their topological nature. Real-time generation of skyrmions is therefore imperative for realizing skyrmion-based spintronic devices. However, to date, experimental demonstration has been limited to exquisite works with well-tuned samples. Here, we report a method to generate skyrmions by driving the stripe instability via an in-plane magnetic field. We have demonstrated that the key parameter determining the stripe domain instability is the stripe width, regardless of other material parameters. This skyrmion generation method can be applicable to generic magnetic films with perpendicular magnetic anisotropy. Our work will facilitate the development of skyrmion-based devices by offering a general method for controlling a large skyrmion population.
This paper presents an analysis of demagnetization of an outer rotor type brushless DC (BLDC) motor with a permanent magnet (PM) overhang structure. The proposed model converts the operating points ...of PM to consider such a three-dimensional (3D) structure in two dimensions (2D). In addition, the rotor yoke thickness of the proposed model is increased to consider the housing rotor. Ferrite PMs require demagnetization analysis owing to their decreasing coercivity at lower temperatures compared with rare-earth PMs. Hence, demagnetization analysis is conducted using a proposed model while considering, the PM overhang structure. The demagnetization analysis results are compared with the results of proposed model and 3D FEA analyses.
ECSIT (evolutionarily conserved signaling intermediate in Toll pathways) is known as a multifunctional regulator in different signals, including Toll-like receptors (TLRs), TGF-β, and BMP. Here, we ...report a new regulatory role of ECSIT in TLR4-mediated signal. By LPS stimulation, ECSIT formed a high molecular endogenous complex including TAK1 and TRAF6, in which ECSIT interacted with each protein and regulated TAK1 activity, leading to the activation of NF-κB. ECSIT-knockdown THP-1 (ECSITKD THP-1) cells exhibited severe impairments in NF-κB activity, cytokine production, and NF-κB-dependent gene expression, whereas those were dramatically restored by reintroduction of wild type (WT) ECSIT gene. Interestingly, ECSIT mutants, which lack a specific interacting domain for either TAK1 or TRAF6, could not restore these activities. Moreover, no significant changes in both NF-κB activity and cytokine production induced by TLR4 could be seen in TAK1KD or TRAF6KD THP-1 cells transduced by WT ECSIT, strongly suggesting the essential requirement of TAK1-ECSIT-TRAF6 complex in TLR4 signaling. Taken together, our data demonstrate that the ECSIT complex, including TAK1 and TRAF6, plays a pivotal role in TLR4-mediated signals to activate NF-κB.
Background: ECSIT as a multifunctional protein is involved in TLR signals. However, its regulatory function is not fully characterized.
Results: ECSIT forms a high molecular endogenous complex including TAK1 and TRAF6, and that leads to activation of TAK1 and NF-κB.
Conclusion: TAK1-ECSIT-TRAF6 complex plays an essential role in TLR4 signals.
Significance: This study identifies a new regulatory role of ECSIT in TLR4-mediated signaling.
•The Korea atomic energy research institute (KAERI) is developing a new concept of cesium-free negative hydrogen (deuterium) ion source based on a two-region arc plasma (TRAP) ion source for a ...neutral beam injection (NBI) system in a fusion tokamak.•Main feature of the TRAP ion source is that the generated plasma has two regions (a high-energy electron region and a low-energy electron region) without an external magnetic filter field.•the pressure distribution in the TRAP ion source test facility was calculated using 3-dimentional molflow+ program. Subsequently, based on the pressure distribution calculations, we developed a 1-D Monte-Carlo program capable of calculating the quantity of negative ion lost within beam extractor and the generation of backstreaming positive ions.•The computational results indicated that H- ions may experience losses of 20–50 % within beam extractor for gas flow rates ranging from 30 to 60 sccm. Moreover, the losses in the test chamber are estimated to be approximately 60–95 %. Therefore, it is crucial to reduce the pressure within the test chamber.
Korea Atomic Energy Research Institute (KAERI) is currently developing a Two Region Arc Plasma (TRAP) negative ion source for neutral beam injection (NBI) systems of a fusion tokamaks which is characterized by two distinct regions with different plasma temperatures without the use of external filter field magnets. The source has recently been designed, manufactured, and installed for testing. Plasma discharge characterization experiments of the TRAP ion source are presently in progress, with planned beam extraction experiments. The beam extractor of the TRAP ion source is capable of accelerating hydrogen ions up to 30 keV and comprises four grids with slit-type aperture structure. Understanding the negative ion beam loss in the extractor is crucial for expecting potential issue within the beam extractor and comprehending the plasma discharge characteristics through negative ion beam. Using a 3-D Monte Carlo program (molflow+), we calculated the vacuum pressure distribution within the TRAP ion source experimental device, and based on these results, we calculated the loss of negative ion beams within the beam extractor and the neutralization efficiency from the beam exit to the target, an effect arising from residual gases. The computational results reveal that approximately 20 ∼ 50 % of the negative ion beam is lost within the beam extractor, and a reduction of more than 60 % in negative current occurs from the beam exit grid to the target within the test chamber due to neutralization of negative ions.
As rare-earth permanent magnet prices continue to fluctuate, interest in non-rare-earth permanent magnet-assisted synchronous reluctance motors (PMa-SynRMs) is increasing. However, non-rare-earth ...PMa-SynRMs have a multi-layer structure with interior permanent magnets to compensate for the low magnetic fields. Therefore, the rotor has several design parameters, and electromagnetic analysis is time-consuming. To overcome these challenges, magnetic equivalent circuit analysis was used to perform fast electromagnetic analysis of non-rare-earth PMa-SynRMs. In addition, the validity of the proposed method was confirmed through a comparison of the obtained results with those of finite element analysis.
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