Experimental demonstration of combination-encoding content-addressable memory of 0.75 bits per switch utilizing Hf-Zr-O ferroelectric tunnel junctions.

We experimentally demonstrate the concept of combination-encoding content-addressable memory (CECAM) that offers much higher content density than any other content-addressable memory devices proposed to date. In this work, CECAM was fabricated and validated with a hafnium-zirconium oxide (HZO) ferroelectric tunnel junction (FTJ) crossbar array. The new CAM structure, which utilizes nonvolatile memory devices, offers numerous advantages including low-current operation (FTJ), standby power reduction (ferroelectric HZO), and increased content density. Multibit data are encoded and stored in multi-switch CECAM. Perfect-match searching in CECAM with a reasonable match current (lower than nA) for different sizes of CECAM has been validated from a novel CAM device. We demonstrate N-CECAM (with keys encoded into 2N-long binary arrays) for N = 3 (using 6 FTJs) and 4 (using 8 FTJs), leading to content densities of 0.667 and 0.75 bits per switch, which highlight 33% and 50% increase in content density compared to that of the conventional TCAM (0.5 bits per switch).

COFT-AD: COntrastive Fine-Tuning for Few-Shot Anomaly Detection.

Existing approaches towards anomaly detection (AD) often rely on a substantial amount of anomaly-free data to train representation and density models. However, large anomaly-free datasets may not always be available before the inference stage; in which case an anomaly detection model must be trained with only a handful of normal samples, a.k.a. few-shot anomaly detection (FSAD). In this paper, we propose a novel methodology to address the challenge of FSAD which incorporates two important techniques. Firstly, we employ a model pre-trained on a large source dataset to initialize model weights. Secondly, to ameliorate the covariate shift between source and target domains, we adopt contrastive training to fine-tune on the few-shot target domain data. To learn suitable representations for the downstream AD task, we additionally incorporate cross-instance positive pairs to encourage a tight cluster of the normal samples, and negative pairs for better separation between normal and synthesized negative samples. We evaluate few-shot anomaly detection on 3 controlled AD tasks and 4 real-world AD tasks to demonstrate the effectiveness of the proposed method.

Formation techniques for upper active channel in monolithic 3D integration: an overview.

The concept of three-dimensional stacking of device layers has attracted significant attention with the increasing difficulty in scaling down devices. Monolithic 3D (M3D) integration provides a notable benefit in achieving a higher connection density between upper and lower device layers than through-via-silicon. Nevertheless, the practical implementation of M3D integration into commercial production faces several technological challenges. Developing an upper active channel layer for device fabrication is the primary challenge in M3D integration. The difficulty arises from the thermal budget limitation for the upper channel process because a high thermal budget process may degrade the device layers below. This paper provides an overview of the potential technologies for forming active channel layers in the upper device layers of M3D integration, particularly for complementary metal-oxide-semiconductor devices and digital circuits. Techniques are for polysilicon, single crystal silicon, and alternative channels, which can solve the temperature issue for the top layer process.

In vitro and in silico cytotoxic activities of triterpenoids from the leaves of Aralia dasyphylla Miq. and the assessment of their ADMET properties.

From the methanol extract of the leaves of Aralia dasyphylla Miq. (Araliaceae), ten triterpenoids including five ursane-type triterpenoids, ursolic acid (1), 3-O-α-l-arabinopyranosyl ursolic acid (2), ursolic acid 28-O-ß-D-glucopyranosyl ester (3), 3-O-[ß-D-glucopyranosyl (l→3)]-α-L-arabinopyranosyl ursolic acid (4), and matesaponin 1 (5), and five oleanane-type triterpenoids, elatoside E (6), elatoside F (7), 3-O-[ß-D-glucopyranosyl (l→3)]-α-L-arabinopyranosyl oleanolic acid (8), 3-O-α-L-arabinopyranosyl oleanolic acid (9) and oleanolic acid 28-O-ß-D-glucopyranosyl ester (10) were isolated. Their structures were elucidated based on 1D-, 2D-NMR and ESI-MS spectra as well as by comparison with those reported in the literature. All isolated compounds were evaluated in vitro for their cytotoxic activities against three human cancer cell lines (HepG2, LU-1 and RD) and in silico by molecular docking studies on human glucose transporter 1 (hGLUT1) protein. The triterpenoids 2, 4, 6, 8 and 9 exhibited good growth inhibition of HepG2 and LU-1 cancer cell lines with IC50 values in the range 1.76 - 7.21 (µM). The oleanane type triterpenoid 8 was the highest cytotoxic compound to inhibit all the tested cancer cell lines with IC50 values of 2.73 ± 0.12, 1.76 ± 0.11, 2.63 ± 0.10 µM, respectively. The in silico molecular docking study results showed that compounds 4 and 6 had the highest binding affinity. Compounds 1-10 were evaluated for their in silico ADMET of absorption, distribution, metabolism, excretion and oral toxicity parameters. Compounds 6, 8, 9 and 10 from A. dasyphylla are potential hGLUT1 inhibitors and worth of further investigation for the prevention or treatment of diabetes and cancer.Communicated by Ramaswamy H. Sarma.

Impact of Pt grain size on ferroelectric properties of zirconium hafnium oxide by chemical solution deposition.

The effects of the grain size of Pt bottom electrodes on the ferroelectricity of hafnium zirconium oxide (HZO) were studied in terms of the orthorhombic phase transformation. HZO thin films were deposited by chemical solution deposition on the Pt bottom electrodes with various grain sizes which had been deposited by direct current sputtering. All the samples were crystallized by rapid thermal annealing at 700 °C to allow a phase transformation. The crystallographic phases were determined by grazing incidence X-ray diffraction, which showed that the bottom electrode with smaller Pt grains resulted in a larger orthorhombic phase composition in the HZO film. As a result, capacitors with smaller Pt grains for the bottom electrode showed greater ferroelectric polarization. The smaller grains produced larger in-plane stress which led to more orthorhombic phase transformation and higher ferroelectric polarization.

SemiCurv: Semi-Supervised Curvilinear Structure Segmentation.

Recent work on curvilinear structure segmentation has mostly focused on backbone network design and loss engineering. The challenge of collecting labelled data, an expensive and labor intensive process, has been overlooked. While labelled data is expensive to obtain, unlabelled data is often readily available. In this work, we propose SemiCurv, a semi-supervised learning (SSL) framework for curvilinear structure segmentation that is able to utilize such unlabelled data to reduce the labelling burden. Our framework addresses two key challenges in formulating curvilinear segmentation in a semi-supervised manner. First, to fully exploit the power of consistency based SSL, we introduce a geometric transformation as strong data augmentation and then align segmentation predictions via a differentiable inverse transformation to enable the computation of pixel-wise consistency. Second, the traditional mean square error (MSE) on unlabelled data is prone to collapsed predictions and this issue exacerbates with severe class imbalance (significantly more background pixels). We propose a N-pair consistency loss to avoid trivial predictions on unlabelled data. We evaluate SemiCurv on six curvilinear segmentation datasets, and find that with no more than 5% of the labelled data, it achieves close to 95% of the performance relative to its fully supervised counterpart.

Synthesis of wool roll-like silver nanoflowers in an ethanol/water mixture and their application to detect traces of the fungicide carbendazim by SERS technique.

The Raman signal enhancement ability of the surface-enhanced Raman scattering (SERS) technique is largely determined by the SERS substrate, which is usually a collection of precious metal (such as silver or gold) nanoparticles. For use in the SERS substrate, anisotropic metal nanoparticles, e.g. flower-like, will be preferred over the isotropic ones since they will give higher Raman enhancement. The problem is that it is very difficult to fabricate anisotropic metal nanoparticles as small as the isotropic ones that are best suited for use as SERS substrates. This study deals with the synthesis of wool roll-like silver nanoflowers (AgNFs) in a mixed ethanol/water solution instead of the usual aqueous solution when reducing silver nitrate with ascorbic acid in the presence of citric acid, which acts as a structure-directing agent. The size of the wool roll-shaped AgNFs was reduced from about 700 nm when the solution was purely aqueous to about 280 nm when in the mixed solution the ethanol/water volume ratio was 75/25. Thanks to the size reduction of AgNFs, the enhancement factor of SERS substrates made from them has increased dramatically, from 2.7 × 106 when the size of AgNFs is 700 nm to 5.4 × 109 when their size is 280 nm (the calculation is based on rhodamine 6G Raman and SERS spectroscopy). The application of the above AgNFs to recording the SERS spectrum of carbendazim (CBZ), a typical fungicide, at low concentrations has also shown that the smaller the size of the AgNFs, the higher the intensity of the CBZ characteristic bands. The wool roll-shaped AgNFs with a size of 280 nm allowed CBZ to be detected down to a concentration of 0.01 ppm (4.2 × 10-8 M) with a detection limit of 3.2 ppb (13.4 × 10-9 M).

Dammarane triterpenes and phytosterols from Dysoxylum tpongense Pierre and their anti-inflammatory activity against liver X receptors and NF-κB activation.

Dysoxylum tpongense Pierre (local name 'Huynh Dan Bap') belonging to family Meliaceae, is a tree (3-10 m height), distributed in the mountainous areas (ca. 1000 m a.s.l.) in North Vietnam. From the dichloromethane fraction of the methanol extract of the leaves and stems of this plant, six dammarane triterpenes, one furanoid diterpene together with three sterols were isolated. Evaluation of biological activities of isolated compounds showed that cabraleahydroxylactone (5), cabraleahydroxylactone 3-acetate (6), and stigmast-4-en-3-one (10) possessed an anti-inflammatory effect against Liver X receptor (LXR) activation in HepG2 cell line model with IC50 values of 20.29 ± 3.69, 24.32 ± 2.99, and 7.09 ± 0.97 (µM), respectively. While three other triterpenoid compounds aglinin C 3- acetate (1), aglinin C (2), and 24-epi-cabraleadiol (4) presented the most significant inhibitory effect against TNF-α induced NF-κB activation in HepG2 cell line in a dose-dependent manner with IC50 values of 12.45 ± 2.37, 23.32 ± 3.25, and 13.95 ± 1.57 µM, respectively. As stigmast-4-en-3-one (10), with structure closely similar to cholesterol, acted selectively on LXRs but not on NF-kB activation pathway, this suggests that stigmast-4-en-3-one (10) can be potentially applied as an agonist on LXR signaling pathway. Pathways LXRs-NF-κB-iNOS expression have a close relationship and play a crucial role in proceeding metabolic abnormalities like atherosclerosis, obesity, inflammation, etc. Thus, the findings showed that dammarane-type triterpenoids from D. tpongense are worthy of further investigation for potential LXR agonists and potent anti-atherogenic agents against atherosclerotic lesion progression.

Double-gate thin film transistor with suspended-gate applicable to tactile force sensor.

This paper presents a straightforward, low-cost, and effective integration process for the fabrication of membrane gate thin film transistors (TFTs) with an air gap. The membrane gate TFT with an air gap can be used as the highly sensitive tactile force sensor. The suspended membrane gate with an air gap as the insulator layer is formed by multiple photolithography steps and photoresist sacrificial layers. The viscosity of the photoresist and the spin speed was used to modify the thickness of the air gap during the coating process. The tactile force was measured by monitoring the drain current of the TFT as the force changed the thickness of the air gap. The sensitivity of the devices was enhanced by an optimal gate size and low Young's modulus of the gate material. This simple process has the potential for the production of small, versatile, and highly sensitive sensors.

Residual Image Suppression Through Annealing Process of Amorphous Indium Gallium Zinc Oxide Thin Film Transistor for Plastic Organic Light-Emitting Diode Display.

For the evaluation of the residual image suppression, the amorphous indium-gallium-zinc-oxide thin film transistor was manufactured with electric field shield metal on silicon oxide multi-buffer layer, without the need for a silicon crystallization process through the excimer laser process, and is advantageous for the manufacture of large-scale plastic organic light-emitting display. We conducted a study on the propensity to suppress a residual image according to the temperature of the annealing process in amorphous indium gallium zinc oxide. The evaluation divided by the ambient process temperature conditions to measure the change and restoration tendency of the gray current by the black/white current of thin film transistors, and for precise measurement of the current change intervals, the current was analyzed in 0.004 seconds per point. Through the study, residual image of amorphous Indium Gallium Zinc Oxide transistor was found to be suppressed as the temperature of the annealing crystallization increased from 250°C to 325°C, and there was no improvement effect on the 325°C or higher. The trend of threshold voltage shift of thin film transistors according to the two process temperature conditions, 250°C and 325°C, was analyzed by Two sample T analysis method, and the analysis confirmed that the trend of current deterioration is different through p-value 0.007.

Residual Image Reduction Using Electric Field Shield Metal in Plastic Organic Light-Emitting Diode Display.

A plastic organic light-emitting diode display is a device that emits light in an organic layer in proportion to the amount of current applied from a thin film transistor, which constitutes a pixel. However, it was confirmed that the residual image was shown by the operation of the thin film transistor. To suppress residual image, the effect of electric field was studied in operation of a-IGZO thin film transistor. The a-IGZO thin film transistor, in which a polyimide film was used as a substrate, was applied as a driving thin film transistor for pixel circuits in a plastic organic light-emitting diode display, and the effect of the electric field behavior inside the film on residual images was studied. Residual images were strongly connection with the electric field distribution characteristics inside the polyimide substrate, and they were reduced by introducing an electric field shield metal layer in the a-IGZO thin film transistor. The correlation between residual image generation and the operation of the a-IGZO thin film transistor was further explained through technology computer-aided design simulation (Silvaco Group Inc.).

Minimizing Residual Images of Amorphous Indium Gallium Zinc Oxide Thin-Film Transistor-Based Flexible Organic Light-Emitting Diode Displays by Controlling Oxygen Partial Pressure.

Plastic organic light emitting diode displays suffer from residual image, which is closely connected with the hysteresis of the driving thin-film transistor in the pixels. Therefore, in researching paper, we manufactured an OLED display comprise a polyimide substrate and an amorphous indium gallium zinc oxide thin film transistor active layer. Paper proposed a solution for reducing hysteresis through oxygen partial pressure control and evaluated it using hysteresis analysis. The results showed that hysteresis is strongly dependent on the threshold voltage is settled by the oxygen partial pressure while active layer deposition of the TFT. Moreover, hysteresis decreases with increasing temperature.

Optimal Nitrogen Incorporation in Nickel Silicide for Thermally Stable Contact Formation.

Nickel silicide (NiSi) is commonly used as a contact material for metal junctions but the poor thermal instability of NiSi above 600 °C has limited the further scaling down of devices and the implementation of novel schemes, such as monolithic 3-dimensional integration. This paper suggests a process to improve the thermal stability of NiSi through nitrogen incorporation during the silicidation process. The optimal level of nitrogen incorporation in NiSi reduced the nickel diffusion rate and enhanced the thermal stability by preventing the formation of a nickel disilicide phase. On the other hand, a higher level of N incorporation led to Ni3N formation, which impeded the complete transformation to NiSi. Therefore, it is essential to incorporate the optimal content of N. In this study, NiSi with 3.9% N incorporation showed superior electrical characteristics, such as the sheet resistance, junction leakage, and stable Schottky barrier height, even after high-temperature post silicidation annealing at 600 °C for 30 min.

Identification of Soluble Epoxide Hydrolase Inhibitors from the Seeds of Passiflora edulis Cultivated in Vietnam

Soluble epoxide hydrolases (sEH) are enzymes present in all living organisms, metabolize epoxy fatty acids to 1,2-diols. sEH in the metabolism of polyunsaturated fatty acids plays a key role in inflammation. In addition, the endogenous lipid mediators in cardiovascular disease are also broken down to diols by the action of sEH that enhanced cardiovascular protection. In this study, sEH inhibitory guided fractionation led to the isolation of five phenolic compounds trans-resveratrol (1), trans-piceatannol (2), sulfuretin (3), (+)-balanophonin (4), and cassigarol E (5) from the ethanol extract of the seeds of Passiflora edulis Sims cultivated in Vietnam. The chemical structures of isolated compounds were determined by the interpretation of NMR spectral data, mass spectra, and comparison with data from the literature. The soluble epoxide hydrolase (sEH) inhibitory activity of isolated compounds was evaluated. Among them, trans-piceatannol (2) showed the most potent inhibitory activity on sEH with an IC₅₀ value of 3.4 µM. This study marks the first time that sulfuretin (3) was isolated from Passiflora edulis as well as (+)-balanophonin (4), and cassigarol E (5) were isolated from Passiflora genus.

Fe-Si networks and charge/discharge-induced phase transitions in Li2FeSiO4 cathode materials.

Structural phase transitions of electrode materials are responsible for poor reversibility during charge/discharge cycling in Li-ion batteries. Using previously developed structural databases, we investigate a structural landscape for LixFeSiO4 systems at x = 1. Starting with low-energy Li2FeSiO4 crystal structures, we explore the crystal structures of the material in different states of charge. The as-prepared Li2FeSiO4 materials adopt low energy structures characterized by two-dimensional (2D) Fe-Si networks. After the removal of one Li per formula unit to form LiFeSiO4, the structures with three-dimensional (3D) diamond-like Fe-Si networks become more energetically favorable without a significant impact on the charge capacity, which agrees with previous experimental and theoretical work. However, we reveal that the structure with a 3D diamond-like Fe-Si network can further transform into a new structure at x = 1. And the Li atom is hard to reinsert into these new structures. Consequently the system is prevented from returning to the Li2FeSiO4 state. We believe that the formation of this new structure plays an important role in the loss of reversible capacity of Li2FeSiO4 electrode materials.

Magnetocrystalline anisotropy in cobalt based magnets: a choice of correlation parameters and the relativistic effects.

The dependence of the magnetocrystalline anisotropy energy (MAE) in MCo5 (M = Y, La, Ce, Gd) and CoPt on the Coulomb correlations and strength of spin orbit (SO) interaction within the GGA + U scheme is investigated. A range of parameters suitable for the satisfactory description of key magnetic properties is determined. We show that for a large variation of SO interaction the MAE in these materials can be well described by the traditional second order perturbation theory. We also show that in these materials the MAE can be both proportional and negatively proportional to the orbital moment anisotropy (OMA) of Co atoms. Dependence of relativistic effects on Coulomb correlations, applicability of the second order perturbation theory for the description of MAE, and effective screening of the SO interaction in these systems are discussed using a generalized virial theorem. Such determined sets of parameters of Coulomb correlations can be used in much needed large scale atomistic simulations.

Elastic and electronic tuning of magnetoresistance in MoTe2.

Quasi-two-dimensional transition metal dichalcogenides exhibit dramatic properties that may transform electronic and photonic devices. We report on how the anomalously large magnetoresistance (MR) observed under high magnetic field in MoTe2, a type II Weyl semimetal, can be reversibly controlled under tensile strain. The MR is enhanced by as much as ~30% at low temperatures and high magnetic fields when uniaxial strain is applied along the a crystallographic direction and reduced by about the same amount when strain is applied along the b direction. We show that the large in-plane electric anisotropy is coupled with the structural transition from the 1T' monoclinic to the Td orthorhombic Weyl phase. A shift of the Td-1T' phase boundary is achieved by minimal tensile strain. The sensitivity of the MR to tensile strain suggests the possibility of a nontrivial spin-orbital texture of the electron and hole pockets in the vicinity of Weyl points. Our ab initio calculations show a significant orbital mixing on the Fermi surface, which is modified by the tensile strains.

Effects of H2 High-pressure Annealing on HfO2/Al2O3/In0.53Ga0.47As Capacitors: Chemical Composition and Electrical Characteristics.

We studied the impact of H2 pressure during post-metallization annealing on the chemical composition of a HfO2/Al2O3 gate stack on a HCl wet-cleaned In0.53Ga0.47As substrate by comparing the forming gas annealing (at atmospheric pressure with a H2 partial pressure of 0.04 bar) and H2 high-pressure annealing (H2-HPA at 30 bar) methods. In addition, the effectiveness of H2-HPA on the passivation of the interface states was compared for both p- and n-type In0.53Ga0.47As substrates. The decomposition of the interface oxide and the subsequent out-diffusion of In and Ga atoms toward the high-k film became more significant with increasing H2 pressure. Moreover, the increase in the H2 pressure significantly improved the capacitance‒voltage characteristics, and its effect was more pronounced on the p-type In0.53Ga0.47As substrate. However, the H2-HPA induced an increase in the leakage current, probably because of the out-diffusion and incorporation of In/Ga atoms within the high-k stack.

Structures of defects on anatase TiO2(001) surfaces.

Defects on oxide surfaces play a crucial role in surface reactivity and thus it is crucial to understand their atomic and electronic structures. The defects on anatase TiO2(001)-(1 × 4) surfaces are found to be highly reactive; however, due to the surface reconstruction, the defects exhibit a complicated character in different experiments that make it very challenging to determine their atomic structures. Here we present a systematic first-principles investigation of the defects on anatase TiO2(001)-(1 × 4) surfaces based on a global-search adaptive genetic algorithm (AGA) and density functional theory (DFT). For different Ti-O ratios, we identify the low energy defect structures, investigate their electronic structure using a hybrid functional, and map their regions of stability under realistic conditions. We successfully find novel oxygen vacancy (OV) and Ti interstitial (Tiini) structures that are different from the conventional ones in terms of their charge localization, magnetic state, and their scanning-tunneling-microscopy bright-dark image signature. This provides an insight into the complex geometric and electronic structure of the surface defects, and resolves several experimental discrepancies.

Role of Surface Stress on the Reactivity of Anatase TiO2(001).

In contrast with theoretical predictions in which anatase TiO2(001) and its (1 × 4) reconstructed surfaces are highly reactive, recent experimental results show this surface to be inert except for the defect sites. In this report, based on a systematic study of anatase TiO2(001)-(1 × 4) surface using first-principles calculations, the tensile stress is shown to play a crucial role on the surface reactivity. The predicted high reactivity based on add-molecule model is due to the large surface tensile stress, which can be easily suppressed by a stress-release mechanism. We show that various surface defects can induce stress release concomitantly with surface passivation. Thus the synthesis of anatase(001) surface with few defects is essential to improve the reactivity, which can be achieved, for example, via H2O adsorption. Our study provides a uniform interpretation of controversial experimental observations and theoretical predictions on anatase TiO2(001) surface and further proposes new insights into the origin of surface reactivity.