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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]

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.

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]