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Understanding the density of state (DOS) distribution in solution-processed indium-zinc-oxide (IZO) thin-film transistors (TFTs) is crucial for addressing electrical instability. This paper presents quantitative calculations of the acceptor-like state distribution of solution-processed IZO TFTs using thermal energy analysis. To extract the acceptor-like state distribution, the electrical characteristics of IZO TFTs with various In molarity ratios were analyzed with respect to temperature. An Arrhenius plot was used to determine electrical parameters such as the activation energy, flat band energy, and flat band voltage. Two calculation methods, the simplified charge approximation and the Meyer-Neldel (MN) rule-based carrier-surface potential field-effect analysis, were proposed to estimate the acceptor-like state distribution. The simplified charge approximation established the modeling of acceptor-like states using the charge-voltage relationship. The MN rule-based field-effect analysis validated the DOS distribution through the carrier-surface potential relationship. In addition, this study introduces practical and effective approaches for determining the DOS distribution of solution-processed IZO semiconductors based on the In molarity ratio. The profiles of the acceptor-like state distribution provide insights into the electrical behavior depending on the doping concentration of the solution-processed IZO semiconductors.

Testing of blip and cancellation coils for the Samsung Superconductor Test Facility (SSTF) for KSTAR (Korea Tokamak Advanced Research) is described and discussed.

Research involving the Samsung Superconductor Test facility (SSTF) at the Samsung Advanced Institute of Technology (SAIT) is discussed. Initially, the goal is to test samples of the cable in conduit conductor (CICC) for the Korea Superconducting Tokamak Advanced Research (KSTAR) magnets with fast-varying electromagnetic disturbances.

The Korean Superconducting Tokamak Advanced Research project is discussed in terms of studying the quench in the cable-in-conduit conductor using the adaptive mesh finite volume method.

The Samsung Superconducting Test Facility was analyzed in terms of induced voltage based on self-inductance and mutual inductance calculations.

The Samsung Superconductor Test Facility, testing the KSTAR magnet, at the Samsung Advanced Institute of Technology, is described.

The atomic composition ratio of solution-processed oxide semiconductors is crucial in controlling the electrical performance of thin-film transistors (TFTs) because the crystallinity and defects of the random network structure of oxide semiconductors change critically with respect to the atomic composition ratio. Herein, the relationship between the film properties of nitrate precursor-based indium-zinc-oxide (IZO) semiconductors and electrical performance of solution-processed IZO TFTs with respect to the In molar ratio was investigated. The thickness, morphological characteristics, crystallinity, and depth profile of the IZO semiconductor film were measured to analyze the correlation between the structural properties of IZO film and electrical performances of the IZO TFT. In addition, the stoichiometric and electrical properties of the IZO semiconductor films were analyzed using film density, atomic composition profile, and Hall effect measurements. Based on the structural and stoichiometric results for the IZO semiconductor, the doping effect of the IZO film with respect to the In molar ratio was theoretically explained. The atomic bonding structure by the In doping in solution-processed IZO semiconductor and resulting increase in free carriers are discussed through a simple bonding model and band gap formation energy.

Understanding the chemical reaction pathway of the metal-salt precursor is essential for modifying the properties of solution-processed metal-oxide thin films and further improving their electrical performance. In this study, we focused on the structural growth of solution-processed amorphous indium-zinc-oxide ( a -IZO) films and the electrical behavior of a -IZO thin-film transistors (TFT). To this end, solution-processed a -IZO films were prepared with respect to the Zn molar ratio, and their structural characteristics were analyzed. For the structural characteristic analysis of the a -IZO film, the cross-section, morphology, crystallinity, and atomic composition characteristics were used as the measurement results. Furthermore, the chemical reaction pathway of the nitrate precursor-based IZO solution was evaluated for the growth process of the a -IZO film structure. These interpretations of the growth process and chemical reaction pathway of the a -IZO film were assumed to be due to the thermal decomposition of the IZO solution and the structural rearrangement after annealing. Finally, based on the structural/chemical results, the electrical performance of the fabricated a -IZO TFT depending on the Zn concentration was evaluated, and the electrical behavior was discussed in relation to the structural characteristics.

A background-field magnet is being developed for the Samsung Superconductor Test Facility (SSTF). It will be used for a test involving the Korea Superconducting Tokamak Advanced Research (KSTAR) device.

Semitransparent dual-metal electrodes comprising several thin layers of metals, such as Ni, Ag, Cu, and Al, were developed for designing flexible red-phosphorescent organic light-emitting diodes (OLEDs). The said diodes were fabricated by first depositing a Ni layer on four glass and polyethylene terephthalate (PET) substrates each to facilitate adhesion with glass and a flexible PET substrate. Subsequently, a conductive layer of Ni, Ag, Cu, and Al was stacked atop the first Ni layer on the four glass and PET substrates each, respectively. The proof of principles has been employed to demonstrate the performance potential via optical, physical, and electrical analyses of dual-as well as single-metal layers prior to device realization. In addition, their electrical and optical characteristics were compared against those of In-Sn-oxide-based OLEDs to demonstrate their potential with regard to application flexibility.

We investigate the electrical characteristics of solution-processed poly(3-hexylthiophene-2,5-diyl) (P3HT) thin-film transistors (TFTs) under monochromatic illumination conditions at different wavelengths of 700, 655, 515, and 315 nm. The TFT characteristics measured under light illumination at the wavelengths of 700 and 655 nm were comparable to those measured in the dark state. In addition, light illumination at a wavelength of 515 nm, of which photon energy (~2.4 eV) is higher than the band gap energy of P3HT (~1.7 eV), had a little effect on the electrical characteristics of P3HT TFTs. On the other hand, the TFT performance was notably changed by light illumination at a wavelength of 315 nm. These results indicate that the photon energy, which cause the characteristic degradation in the solution-processed P3HT TFTs, is much higher than the band gap energy of P3HT. Consequently, the illumination-induced variation in the TFT performance can be understood through a broad distribution of energetic states in the solution-processed P3HT semiconductor.

The praseodymium-doped indium zinc oxide (PrIZO) thin-film transistor (TFT) is promising for applications in flat-panel displays, due to its high carrier mobility and stability. Nevertheless, there are few studies on the mechanism of annealing on PrIZO films and the fabrication of flexible devices. In this work, we first optimized the annealing-process parameters on the glass substrate. As the annealing temperature rises, the film tends to be denser and obtains a lower surface roughness, a narrower optical-band gap and less oxygen-vacancy content. However, the μ-PCD test shows the 250 °C-annealed film obtains the least defects. And the PrIZO TFT annealed at 250 °C exhibited a desired performance with a saturation mobility (μsat) of 14.26 cm2·V−1·s−1, a subthreshold swing (SS) of 0.14 V·dec−1, an interface trap density (Dit) of 3.17 × 1011, an Ion/Ioff ratio of 1.83 × 108 and a threshold voltage (Vth) of −1.15 V. The flexible devices were prepared using the optimized parameters on the Polyimide (PI) substrate and subjected to static bending tests. After bending at a radius of 5 mm, the mobility of devices decreases slightly from 12.48 to 10.87 cm2·V−1·s−1, demonstrating the great potential of PrIZO for flexible displays. [ABSTRACT FROM AUTHOR]

Reflectometry is currently used to monitor density fluctuations and turbulent correlation lengths in fusion plasmas. Various models have been used to interpret the experimental data and to determine the regimes of validity of the reflectometer fluctuation measurements. Heretofore, these models have not been validated by direct comparison with experiment. In this paper the first comparison between a controlled laboratory experiment and a one-dimensional numerical model is presented. It is found that the model is unable to predict the observed high degree of spatial localization and dependence on perturbation wave number. The implications of these disagreements are discussed, together with suggestions for their resolution. [ABSTRACT FROM AUTHOR]

Anomalous transport in fusion plasmas remains an enigma requiring explanation. A predictive capability is highly desirable if confinement enhancement regimes such as H mode or super shots are to be extrapolated to the next phase in development of the International Fusion program, epitomized, for example in ITER. Therefore, identification of the role that electrostatic turbulence plays in confinement is a critical issue requiring detailed experimental data capable of testing and challenging existing theoretical models. This article presents microturbulence measurements obtained on the DIII-D and TEXT tokamaks utilizing heterodyne, far-infrared collective scattering, and reflectometry techniques. The experimental systems are described on both machines and emphasis placed on results obtained during the L-H transition, ELM activity, and saturated ohmic operation where ion temperature gradient driven (ITGD) turbulence is theoretically predicted to exist. [ABSTRACT FROM AUTHOR]

Microwave breast tumor detection uses the electrical property contrast between normal tissues and malignancies to detect the latter in an early development stage. However, previous works on the microwave imaging uses 2-D or more complicated models of the breast and electromagnetic wave propagation. We present a computationally efficient and physically instructive electromagnetic wave channel modeling for confocal microwave imaging system for the breast tumor detection. The proposed model covers all of the factors that have been examined in the previous 2-D model, such as the radial spreading, path loss, partial reflection and transmission of the backscattered electromagnetic wave from the tumor cell. The characteristics of the reconstructed images of the tumor using the proposed 1-D model are compared with them of the previous 2-D FDTD method. Previous 2-D model of the cancerous breast utilizes the MRI-derived discretized cell model to simulate the realistic perturbation, but there has been no consideration on the system noise that can be detrimental to the reconstruction of the tumor. The effect of the system noise level to the reconstruction algorithm will be addressed as well.

Reflectometry is currently being used to investigate density fluctuations and turbulence in tokamak plasmas. However, there are unresolved questions about the spatial resolution and wave number sensitivity of this diagnostic method which impact the interpretation of the data. These questions are currently being addressed in a cylindrical, pulsed filament discharge plasma where ion acoustic waves (10-100 kHz) are launched toward the incident microwaves. Preliminary data supporting the spatially localized nature of reflectometry are presented. A computational model is also being developed to provide quantitative comparisons with experiment. [ABSTRACT FROM AUTHOR]

In order to obtain high-quality photocrosslinkable polymer matrix, cinnamoyl chloride functionalized poly(methyl methacrylate-co-2-hydroxyethyl methacrylate) [f-P(MMA-co-HEMA)] was synthesized. The functionalization and photocrosslinking of the polymer were confirmed through FTIR, 1H NMR, and UV characterization. In order to obtain high-quality, flat and pinhole-free polymer films, the effects of different photocrosslinked processes on the polymer film properties were investigated. When the crosslinking time was 10 min and the crosslinking degree was 55%, the dielectric constant of the capacitor reached to 4.65, the dielectric loss was as low as 0.04, the dielectric strength was as high as 334 MV/m, and the energy density was 2.4 J/cm3. In order to obtain composite materials with high dielectric constant, photocrosslinkable functionalized copolymer f-P(MMA-co-HEMA) was used as the polymer matrix, and surface modified BT with phosphoric acid was introduced through ball milling dispersion to prepare photocrosslinkable f-P(MMA-co-HEMA)/m-BT composite film. By surface and cross-sectional SEM characterization, BT was uniformly dispersed in the polymer matrix. FTIR confirmed that the C = C group on the surface modified BT disappeared after photocrosslinking, and the chemical binding was formed between the two phases in the nanocomposite material to obtain a double crosslinking network structure. When the BT content was 30 wt%, the dielectric constant reached up to 51. With the bending angle of 120°, the capacitance value of the flexible dielectric film changed by 27%, indicative of good bending sensitivity. [ABSTRACT FROM AUTHOR]

This paper investigates the bipolar resistive switching and synaptic characteristics of IZO single-layer and IZO/SiO2 bilayer two-terminal memory devices. The chemical properties and structure of the device with a SiO2 layer are confirmed by x-ray photoemission spectroscopy (XPS) and transmission electron microscopy (TEM) imaging. The device with the SiO2 layer showed better memory characteristics with a low current level, as well as better cell-to-cell and cycle-to-cycle uniformity. Moreover, the neuromorphic applications of the IZO/SiO2 bilayer device are demonstrated by pulse response. Paired pulse facilitation, excitatory postsynaptic current, and pulse-width-dependent conductance changes are conducted by the coexistence of short- and long-term memory characteristics. Moreover, Hebbian rules are emulated to mimic biological synapse function. The result of potentiation, depression, spike-rate-dependent plasticity, and spike-time-dependent plasticity prove their favorable abilities for future applications in neuromorphic computing architecture. [ABSTRACT FROM AUTHOR]

The density of donor-like state distributions in solution-processed indium–zinc-oxide (IZO) thin-film transistors (TFTs) is thoroughly analyzed using photon energy irradiation. This study focuses on quantitatively calculating the distribution of density of states (DOS) in IZO semiconductors, with a specific emphasis on their variation with indium concentration. Two calculation methods, namely photoexcited charge collection spectroscopy (PECCS) and photocurrent-induced DOS spectroscopy (PIDS), are employed to estimate the density of the donor-like states. This dual approach not only ensures the accuracy of the findings but also provides a comprehensive perspective on the properties of semiconductors. The results reveal a consistent characteristic: the Recombination–Generation (R-G) center energy ET, a key aspect of the donor-like state, is acquired at approximately 3.26 eV, irrespective of the In concentration. This finding suggests that weak bonds and oxygen vacancies within the Zn-O bonding structure of IZO semiconductors act as the primary source of R-G centers, contributing to the donor-like state distribution. By highlighting this fundamental aspect of IZO semiconductors, this study enhances our understanding of their charge-transport mechanisms. Moreover, it offers valuable insight for addressing stability issues such as negative bias illumination stress, potentially leading to the improved performance and reliability of solution-processed IZO TFTs. The study contributes to the advancement of displays and technologies by presenting further innovations and applications for evaluating the fundamentals of semiconductors. [ABSTRACT FROM AUTHOR]

The unique capabilities of the SPARC tokamak mean that it has the potential to contribute significantly to tokamak science and plasma physics, motivating further collaboration and broader data access beyond the CFS and MIT teams. SPARC is a compact, high-field tokamak that is currently under construction and is predicted to achieve burning plasma conditions once in operation. SPARC experimental data has the potential to advance the understanding of many aspects of tokamak physics, including but not limited to confinement and stability at high field and high density, burning plasma physics, disruption physics, and boundary physics and heat flux management in power plant-relevant conditions. The SPARC team is already a combination of members from Commonwealth Fusion Systems (CFS), a privately funded company, and the Massachusetts Institute of Technology (MIT), a non-profit university. This article describes the opportunities for the SPARC team to work with other researchers to advance toward a fusion power plant on the fastest possible time scales and to simultaneously broaden scientific understanding of plasma physics, meeting the missions of both CFS and academic partners. [ABSTRACT FROM AUTHOR]

Visible light positioning systems (VLP) have attracted significant commercial and research interest because of the many advantages they possess over other applications such as radio frequency (RF) positioning systems. In this work, an experimental configuration of an indoor VLP system based on the well-known Lambertian light emission, is investigated. The corresponding results are also presented, and show that the system retains high enough accuracy to be operational, even in cases of low transmitted power and high background noise. [ABSTRACT FROM AUTHOR]

Medical imaging techniques, including X-ray mammography, ultrasound, and magnetic resonance imaging, play a crucial role in the timely identification and monitoring of breast cancer. However, these conventional imaging modalities have their limitations, and there is a need for a more accurate and sensitive alternative. Microwave imaging has emerged as a promising technique for breast cancer detection due to its non-ionizing, non-invasive, and cost-effective nature. Recent advancements in microwave imaging and sensing techniques have opened up new possibilities for the early diagnosis and treatment of breast cancer. By combining microwave sensing with machine learning techniques, microwave imaging approaches can rapidly and affordably identify and classify breast tumors. This manuscript provides a comprehensive overview of the latest developments in microwave imaging and sensing techniques for the early detection of breast cancer. It discusses the principles and applications of microwave imaging and highlights its advantages over conventional imaging modalities. The manuscript also delves into integrating machine learning algorithms to enhance the accuracy and efficiency of microwave imaging in breast cancer detection. [ABSTRACT FROM AUTHOR]

This study focused on the effects of novel chitosan-ammonium polyphosphate, chitosan, and ammonium polyphosphate additives on the flammable properties of a vinyl ester matrix. A general mechanical process used for reinforcing additives within the matrix, and composites fabricated by the solution casting method through a general mechanical process. The influence of the additives on the resin observed through Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and pore size/surface area evaluation of the additives using the Brunauer–Emmett–Teller analysis. The effect of the different amounts (1, 2, and 3 wt%) of additives on the flammability (horizontal and vertical burn test [UL94], LOI and microcalorimeter test), thermal, and mechanical (dynamic mechanical analysis and flexural test) properties of the vinyl ester composites were investigated. Reinforcement by 3 wt% NCSAPP resulted in an excellent fire extinguishing property (UL-94) with a low peak heat release rate (451 W/g) and appreciably improved mechanical properties. Hence, this study is suitable for the development of sub-structural materials. [ABSTRACT FROM AUTHOR]

The automatic analysis of the surgical process, from videos recorded during surgeries, could be very useful to surgeons, both for training and for acquiring new techniques. The training process could be optimized by automatically providing some targeted recommendations or warnings, similar to the expert surgeon's guidance. In this paper, we propose to reuse videos recorded and stored during cataract surgeries to perform the analysis. The proposed system allows to automatically recognize, in real time, what the surgeon is doing: what surgical phase or, more precisely, what surgical step he or she is performing. This recognition relies on the inference of a multilevel statistical model which uses 1) the conditional relations between levels of description (steps and phases) and 2) the temporal relations among steps and among phases. The model accepts two types of inputs: 1) the presence of surgical tools, manually provided by the surgeons, or 2) motion in videos, automatically analyzed through the Content Based Video retrieval (CBVR) paradigm. Different data-driven statistical models are evaluated in this paper. For this project, a dataset of 30 cataract surgery videos was collected at Brest University hospital. The system was evaluated in terms of area under the ROC curve. Promising results were obtained using either the presence of surgical tools ( A = 0.983) or motion analysis ( A = 0.759). The generality of the method allows to adapt it to other kinds of surgeries. The proposed solution could be used in a computer assisted surgery tool to support surgeons during the surgery. [ABSTRACT FROM AUTHOR]

While visible light communication (VLC) has become the candidate for the wireless technology of the 21st century due to its inherent advantages, VLC based positioning also has a great chance of becoming the standard approach to positioning. Within the last few years, many studies on VLC based positioning have been published, but there are not many survey works in this field. In this paper, an in-depth survey of VLC based positioning systems is provided. More than 100 papers ranging from pioneering papers to the state-of-the-art in the field were collected and classified based on the positioning algorithms, the types of receivers, and the multiplexing techniques. In addition, current issues and research trends in VLC based positioning are discussed. [ABSTRACT FROM AUTHOR]

We investigated the electrical and mechanical stability of flexible 6,13-bis (triisopropylsilylehtynyl)pentacene (TIPS-pentacene) thin-film transistors (TFTs) that were fabricated on polyimide (PI) substrates using cross-linked poly(4-vinylphenol) (c-PVP) and c-PVP/yttrium oxide (Y2O3) nanocomposite films as gate insulators. Compared with the electrical characteristics of TIPS-pentacene TFTs with c-PVP insulators, the TFTs with c-PVP/Y2O3 nanocomposite insulators exhibited enhancements in the drain current and the threshold voltage due to an increase in the dielectric capacitance. In electrical stability experiments, a gradual decrease in the drain current and a negative shift in the threshold voltage occurred during prolonged bias stress tests, but these characteristic variations were comparable for both types of TFT. On the other hand, the results of mechanical bending tests showed that the characteristic degradation of the TIPS-pentacene TFTs with c-PVP/Y2O3 nanocomposite insulators was more critical than that of the TFTs with c-PVP insulators. In this study, the detrimental effect of the nanocomposite insulator on the mechanical stability of flexible TIPS-pentacene TFTs was found to be caused by physical adhesion of TIPS-pentacene molecules onto the rough surfaces of the c-PVP/Y2O3 nanocomposite insulator. These results indicate that the dielectric and morphological properties of polymeric nanocomposite insulators are significant when considering practical applications of flexible electronics operated at low voltages. [ABSTRACT FROM AUTHOR]

A new positive ion source for the Korea Superconducting Tokamak Advanced Research neutral beam injection (KSTAR NBI-1) system was designed, fabricated, and assembled in 2011. The characteristics of the arc discharge and beam extraction were investigated using hydrogen and helium gas to find the optimum operating parameters of the arc power, filament voltage, gas pressure, extracting voltage, accelerating voltage, and decelerating voltage at the neutral beam test stand at the Korea Atomic Energy Research Institute in 2012. Based on the optimum operating condition, the new ion source was then conditioned, and performance tests were primarily finished. The accelerator system with enlarged apertures can extract a maximum 65 A ion beam with a beam energy of 100 keV. The arc efficiency and optimum beam perveance, at which the beam divergence is at a minimum, are estimated to be 1.0 A/kW and 2.5 uP, respectively. The beam extraction tests show that the design goal of delivering a 2 MW deuterium neutral beam into the KSTAR Tokamak plasma is achievable. [ABSTRACT FROM AUTHOR]

An application of multipole moments for the determination of toroidal plasma column shift is presented. First, we present analytical details for using this technique. Then, the principle of different models based on this technique for design and fabrication of a six coils will be presented: four modified Rogowski coils (two cosine coils and two sine coils) and two saddle coils (saddle sine coil and saddle cosine coil). As continuous measurements of magnetic field distribution around the toroidal plasma can be made using these coils, this technique is a good method for the determination of toroidal plasma column shift. [ABSTRACT FROM PUBLISHER]

Tokamak start-up on present-day devices usually relies on inductively induced voltage from a central solenoid. In some cases, inductive startup is assisted with auxiliary power from electron cyclotron radio frequency heating. International Thermonuclear Experimental Reactor, the National Spherical Torus Experiment Upgrade and JT60, now under construction, will make use of the understanding gained from present-day devices to ensure successful start-up. Design of a spherical tokamak (ST) with DT capability for nuclear component testing would require an alternative to a central solenoid because the small central column in an ST has insufficient space to provide shielding for the insulators in the solenoid. Alternative start-up techniques such as induction using outer poloidal field coils, electron Bernstein wave start-up, coaxial helicity injection, and point source helicity injection have been used with success, but require demonstration of scaling to higher plasma current. [ABSTRACT FROM AUTHOR]

For the consideration of superconducting magnet stability, it is important to keep enough temperature margin under the different operating conditions for the plasma discharge in Tokamak. In order to estimate the stability of the magnets for Experimental Advanced Superconducting Tokamak (EAST), the code SAITOKPF is used to analyze the operating characteristics of the Poloidal Field (PF) coils with the actual operating scenarios. The simulated results are validated by the experimental data. It is found that the heat load of PF1-6 coils is much larger than that of the other coils. Therefore, the investigation is emphasized on the PF1-6 coils. The analysis includes the AC losses, temperature distribution in the space, temperature margin, and maximum temperature of strands. [ABSTRACT FROM AUTHOR]

The Korea Superconducting Tokamak Advanced Research (KSTAR) device is aimed at advanced tokamak (AT) research. Three years have passed since it achieved its first plasma in 2008. Because it is a superconducting machine and is working toward AT research, it has unique features in terms of the machine engineering and operation. The toroidal field (TF) magnet coils are made of \Nb3\Sn, which provide high TFs up to 3.5 T, and have been fully tested. The poloidal field (PF) magnet coils, consisting of both \Nb3\Sn and NbTi, which have a maximum current of 25 kA in their design, were tested up to 15 kA. A thermal hydraulic analysis is being conducted for PF magnet coil operation. All plasma-facing components (PFCs) are equipped with water cooled graphite tiles and have the capability of being baked up to 350 ^\circ\C. A startup scenario, which considered both the effect of the ferromagnetic material in the cable in conduit conductor jacket of the magnet coils as well as a nonferromagnetic up-down asymmetry in the cryostat structure, was developed and demonstrated its effectiveness by the last two year's reliable operations. Passive stabilizers and in-vessel control coils (IVCCs) are key components to realize AT operation in KSTAR. The segmented IVCC coils were connected to form circular coils for internal vertical control in 2010, and diverted plasmas with high elongation (\kappa \sim 1.8,\ \delta > 0.6) were achieved. A neutral beam injection (NBI) system was developed aiming at 2 MW, 300 s per ion source which meets the long-pulse requirement of KSTAR. An NBI ion source with a power of 1.7 MW at 100 kV has been commissioned for 10 s. Finally, ELMy H-modes were successfully produced with 1.3-MW NBI power at a plasma current of 0.6 MA in the 2010 campaign. The first H-mode discharge (#4200) in KSTAR was achieved one year earlier than officially planned and was done at BT = 2\ \T with Ip = 0.6\ \MA in a well-balanced double null configuration after boronization on the PFC. Successful operations in the early days of KSTAR including H-mode experiments revealed the capability of advanced and steady-state operation which is essential for the international thermonuclear experimental reactor (ITER) and future fusion reactors. [ABSTRACT FROM PUBLISHER]

The magnetic losses of steels used in high temperature superconducting (HTS) transformers are very important for the transformer's efficient design and for a correct choice of operating conditions. This introduced the necessity to analyze electrical steels behaviour at low temperature in order to characterize their magnetic properties and, in particular, the magnetic losses. Three steels were chosen for this analysis: one non-oriented silicon steel and two different grain-oriented silicon steels. Several measurements of total magnetic losses were made at 77 K and 298 K and for different values of maximum magnetic induction, B, in order to compare the dependence between them at both temperatures. These results are presented in Pronto et al. (European Conference on Applied Superconductivity, ). Subsequently, measurements of hysteresis losses (DC regime) at both temperatures were also made in order to obtain all terms of magnetic losses (hysteresis, classical eddy-current losses, and excess losses). The results are presented in this paper. [ABSTRACT FROM AUTHOR]

Developing a large-scale biomedical multimedia software system is always a challenging task: Satisfaction of sundry and stringent biomedical multimedia related requirements and standards; Heterogeneous software deployment and communication environments; and tangling correlation between data/contents and software functionalities, among others. This paper introduces a novel biomedical multimedia software system developed under Service-Oriented Architecture (SOA). Such a system takes the advantage of interoperability of SOA to solve the heterogeneity and correlation problems. The paper also classifies the system into services, annotation, ontologies, semantics matching, and QoS optimization aspects which may potentially solve the requirements problem: By establishing data ontology with respect to data properties, contents, QoS, and biomedical regulations and expanding service ontology to describe more functional and QoS specifications supported by services, appropriate services for processing biomedical multimedia data may be discovered, performed, tuned up or replaced as needed. Lastly, a biomedical education project that improves the performance of feature extraction and classification processed afterwards is introduced to illustrate the advantages of our software system developed under SOA. [ABSTRACT FROM AUTHOR]

The plasma current position is measured based on the current multipole moment method in the Korea Superconducting Tokamak Advanced Research (KSTAR) device [G. S. Lee et al., Nucl. Fusion 41, 1515 (2001)]. Since a limited number of magnetic probes and flux loops were installed for the first campaign, an iteration method is used to interpolate the magnetic field in the area absent of probes. A numerical technique is developed which automatically compensates for the linear drift of the integrator. The measured plasma position is cross checked with the charge coupled device images. In KSTAR, the plasma current is displaced toward the lower outboard direction during the current initiation phase. This displacement is expected due to eddy currents but the exact amount and direction needs more study. [ABSTRACT FROM AUTHOR]

A study is conducted on the feedback stabilization of resistive wall modes (RWMs) in a tokamak plasma using a toroidal shell model. An analytically tractable form of the RWM dispersion relation is derived in the presence of a set of discrete feedback coil currents. A parametric study is carried out to optimize the feedback system configuration. It is shown that the total toroidal angle of a resistive wall spanned by the feedback coils and the poloidal angular extent of a feedback coil are crucial parameters to determine the efficacy of the feedback system. [ABSTRACT FROM AUTHOR]

The Korea Superconducting Tokamak Advanced Research (KSTAR) Central Solenoid Model Coil (CSMC) was tested at the National Fusion Research Center (NFRC) to verify the design and manufacturing engineering and to ensure reliable operation. The CSMC reached 8.6 T at 20 kA DC operation successfully. We also assessed the AC loss of the CSMC by means of both a sinusoidal wave with a DC offset as well as a triangular pulse. We derived a friction factor correlation of CSMC at room temperature and at cryogenic temperature (4 ∼ 6 K). We also investigated the variation of the friction factor during current charging. The KSTAR PF coil simulation code was validated with inlet and outlet helium temperature, mass flow rate, and pressure drop from the experimental results. The operation temperature margin of the CS1 coil of KSTAR was calculated with the revised KSTAR PF coil simulation coil. [ABSTRACT FROM AUTHOR]

The Korea Superconducting Tokamak Advanced Research (KSTAR) Central Solenoid Model Coil (CSMC) has been developed to validate the design of KSATR CS coil. The thermo-hydraulic characteristics were analyzed for the KSTAR CSMC. The major thermo-hydraulic parameters of the coil are AC losses, strand temperature, coolant temperature, pressure drop and temperature margin. A numerical code has been developed for the thermo-hydaulic analysis of the KSTAR CSMC according to the operating conditions. In this paper, the description of the thermo-hydraulic analysis models and analysis results of CSMC are presented. The total energy deposition due to AC losses in CSMC winding will induce a flow reversal of supercritical helium. The minimum temperature margin is estimated approximately 0.5 K. The maximum temperature in CSMC winding is about 7.6 K. [ABSTRACT FROM AUTHOR]

Progress on Mono Element Internal Tin superconductor is presented for four designs with two incorporating integral Nb barriers as opposed to NbTa barriers added later in the fabrication. Processing information is also presented covering the fabrication of these conductors. Sample testing techniques are discussed that gave stable reproducible results to 10 T at current densities of 3767 A/mm² (noncopper). Current density as a function of magnetic field from 10 to 17 T is measured and analyzed with respect to heat treatment and configuration. A value of 2700 A/mm² in the noncopper at 12 T was achieved in the best though nonoptimized samples. Kramer plots are also presented that show H[sup *] of up to 26 T. Reported "n" values are 33 at 17 T for the highest current density sample. [ABSTRACT FROM AUTHOR]

Examines the influence of cryogenic parameters on the temperature margin of superconducting magnets. Reduction of mass flow rate; Peak temperature rise; Cooling condition of the superconducting strands.

Large superconducting magnets such as ITER (International Thermonuclear Experimental Research) or KSTAR (Korean Superconducting Tokamak Advanced Research) magnet system adopted a cable-in-conduit conductor (CICC) using a forced-flow cooling system. Main optimization criteria for the conductor design of superconducting magnet system are stability margin and CICC cooling requirements. A zero-dimensional method is applied for the calculation of stability and the conductor optimization. In order to increase conductor performance, three different strands, ITER HP-I and HP-TI, and KSTAR HP-III, are tested. The strand characteristics of KSTAR HP-III are measured in the Samsung’s PPMS and Jc measurement system, and applied for this study. Also, the strand diameters, 0.81 mm and 0.78 mm are considered for this study, due to design change. Based on this result, the proposed configuration of CICC has been fabricated. [ABSTRACT FROM AUTHOR]

Reports the results of two-dimensional calculation of eddy currents on external conducting walls induced by low-n external modes. Schemes for the stabilization of the mode; Discussion of the physical interpretations on the computed eddy current; Effects of the partial wall having a poloidal gap on the outboard.

Conventional breast cancer detection techniques including X-ray mammography, magnetic resonance imaging, and ultrasound scanning suffer from shortcomings such as excessive cost, harmful radiation, and inconveniences to the patients. These challenges motivated researchers to investigate alternative methods including the use of microwaves. This article focuses on reviewing the background of microwave techniques for breast tumour detection. In particular, this study reviews the recent advancements in active microwave imaging, namely microwave tomography and radar-based techniques. The main objective of this paper is to provide researchers and physicians with an overview of the principles, techniques, and fundamental challenges associated with microwave imaging for breast cancer detection. Furthermore, this study aims to shed light on the fact that until today, there are very few commercially available and cost-effective microwave-based systems for breast cancer imaging or detection. This conclusion is not intended to imply the inefficacy of microwaves for breast cancer detection, but rather to encourage a healthy debate on why a commercially available system has yet to be made available despite almost 30 years of intensive research. [ABSTRACT FROM AUTHOR]

Visible light positioning techniques employing received signal strength (RSS)–based fingerprints are becoming popular and ubiquitous. However, RSS is more susceptible to signal degradation and environmental changes resulting in location inaccuracies. To minimize these limitations, clustering in conjunction with linear regression is applied to RSS database made up of light intensity variations of light emitting diodes. Optimum cluster size is determined and trained clusters are exploited for location assessment by curtailing the difference between the database readings and cluster centroids. Regression is then applied on the clustered data, which partitions it further and helps refining the results. Simulation results of the proposed algorithm dictate a significant improvement in location estimation accuracy of up to 40 cm in an indoor environment with the dimensions of 5 m × 5 m × 4 m and exhibit superior performance than many state‐of‐the‐art RSS‐based methods. A novel visible light based indoor localization system has been developed utilizing received signal strength (RSS) and machine learning approaches. Results show that signal degradations and other environmental changes resulting location inaccuracies in RSS can be minimized using machine learning techniques. [ABSTRACT FROM AUTHOR]

Recently with the advancement of solid state lighting and the application thereof to Visible Light Communications (VLC), the concept of Visible Light Positioning (VLP) has been targeted as a very attractive indoor positioning system (IPS) due to its ubiquity, directionality, spatial reuse, and relatively high modulation bandwidth. IPSs, in general, have four major components: (1) a modulation, (2) a multiple access scheme, (3) a channel measurement, and (4) a positioning algorithm. A number of VLP approaches have been proposed in the literature and primarily focus on a fixed combination of these elements and moreover evaluate the quality of the contribution often by accuracy or precision alone. In this article, we provide a novel two-phase indoor positioning algorithmic framework that is able to increase robustness when subject to insufficient anchor luminaries and also incorporate any combination of the four major IPS components. [ABSTRACT FROM AUTHOR]

In this article, we have investigated the effect of nanocomposite gate dielectric layer built by alumina (Al2O3) and poly(4-vinyphenol) (PVP) with solution method which could enhance the dielectric capability and decrease the surface polarity. Then, we used modify layer to optimize the surface morphology of dielectric layer to further improve the insulation capability, and finally we fabricated the high-performance and low-voltage organic thin-film transistors by using this nanocomposite dielectric layer. The result shows that the devices with Al2O3:10%PVP dielectric layer with a modified layer exhibited a mobility of 0.49 cm2/Vs, Ion/Ioff ratio of 7.8 × 104, threshold voltage of − 1.2 V, sub-threshold swing of 0.3 V/dec, and operating voltage as low as − 4 V. The improvement of devices performance was owing to the good insulation capability, appropriate capacitance of dielectric layer, and preferable interface contact, smaller crystalline size of active layer. [ABSTRACT FROM AUTHOR]