Search

In this study, electrical measurements on ferroelectric random-access memory by prior x-ray irradiation are conducted. Compared with an unirradiated device, parameters such as current leakage and remnant polarization of the irradiated device were unexpectedly improved. Besides, better reliabilities including the number of endurance times and retention time have also been demonstrated. To clarify the underlying physical mechanism, the electrical properties are analyzed. The current–voltage curve (I–V) implies a change in the grain size in the ferroelectric layer (FL), and the capacitance–voltage curve (C – V) profile indicates that the FL undergoes a phase change during irradiation. Finally, according to the electrical results, a physical model is proposed as an explanation. [ABSTRACT FROM AUTHOR]

Thymoma is a rare tumour that often occurs in the anterior mediastinum. Thymomas are usually diagnosed in middle-aged patients, and nearly half of cases are associated with myasthenia gravis. Thymomas typically progress through direct invasion of the thoracic cavity with extra-thoracic distant metastasis being uncommon. Here we report the case of a male patient who underwent an extensive thymectomy and radiotherapy 10 years before presentation, and in whom we detected a spleen tumour during regular out-patient follow-up. The patient underwent a splenectomy, and a final diagnosis of type B3 malignant thymoma was established. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive investigation of the impact of the deposition temperature on the HfxZr1−xO2 (HZO) ferroelectric layer of ferroelectric random access memory with TaN electrodes. This investigation mainly focuses on its electrical characteristics and compares the differences. It is revealed that the deposition temperature plays a crucial role in determining the crystal structure of HZO, which can exhibit a combination of tetragonal and orthorhombic phases or exist solely in one of the two phases. Furthermore, the grain size of HZO varies with the deposition temperature. These findings correspond well to the electrical measurement results, including leakage current, polarization, capacitance, and reliability tests. The study tracks the phase transition process during the operation of switching cycles when the phase transition process can be monitored as well. To better understand the observed differences, physical models that shed light on the underlying mechanisms affected by deposition temperature are proposed at the end of the article. [ABSTRACT FROM AUTHOR]

Abstract: Scaffold design has become a popular research topic in recent years, likely because of the high rate of collapse for this structural form and its nature of under estimated loads close to the design loads, as opposed to permanent structures under remote statistical live and wind loads. This paper investigates the load capacities and failure modes of the system scaffold structure in various setups in construction and it is based on experimental tests supplemented by analyses. The parameters for system scaffolds studied in this paper include number of stories, ground heights, boundary conditions, presence of diagonal bracings and joint positions. The numerical studies quantify the load capacity of a system scaffold against addition of diagonal bracings. However, the load capacities of a system scaffold structure with varied spigot-joint positions on vertical props and with varied ground heights do not affect much the load capacity. Since the axial force of diagonal bracings on a system scaffold structure does not significantly increase with the vertical load, the diagonal bracings of the structure can be reduced in size for cost saving. A comparison between analyses and experimental tests conducted in this study confirmed the joint stiffness of different members used in the system scaffolds. Using the joint stiffness, the ultimate design loads of the system scaffolds with different number of stories were computed and quantified. The findings will be useful for accurate determination of the ultimate load capacity of complex system scaffolds used in construction sites. [Copyright &y& Elsevier]

Herein, the supercritical hydrogen treatment is proposed to improve the performance of zinc oxide‐based resistive random access memory. After treatment, the treated device not only achieves the forming‐free characteristic but also gets enhanced in its memory window, reset voltage, and reliability. Moreover, X‐Ray photoelectron spectroscopy analysis confirms the forming‐free characteristic of the treated device since the treatment decreases the concentration of ZnO bonding in the zinc oxide thin film, leading the conductive filament to be constructed in the zinc oxide switching layer. Next, the carrier transport mechanism is investigated by fitting current–voltage curves. Finally, the physical models based on the electrical properties and the material analyses are introduced to illustrate the oxygen ions and hydroxide ions that create the forming‐free characteristic and better memory characteristics in the random access memory device after the supercritical fluid treatment. Hence, this method demonstrates the promising practical and effective utilization of enhancing memory devices, in the future. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the TiSi(N,O) coating was deposited on tungsten carbide and SKH51 steel substrates using cathodic arc plasma deposition. A compound interface was designed and implemented in this coating, comprising a series of Ti, TiN, and TiSiN interlayers deposited in a continuous structure, between the TiSi(N,O) top coating and substrate. The TiSi(N,O) composition was varied by changing the oxygen flow rate during the deposition process. The phase structure, chemical composition, and morphology of coatings were observed by utilizing X-ray diffractometer, Auger electron spectrometer and scanning electron microscope. The corrosion behaviors of the coatings were studied in aerated 3.5 wt.% NaCl aqueous solutions by interpretation of the electrochemical anodic polarization curves. The tribological performance of TiSi(N,O) coatings was evaluated using a ball-on-disk tribometer. The results showed that the corrosion resistance of TiSi(N,O) coatings was deteriorated than that of TiSiN coating. However, the TiSi(N,O) coatings exhibit lower friction coefficient than that of TiSiN coatings. [Copyright &y& Elsevier]

Background: The mechanism of oral squamous cell carcinoma (SCC) invading jawbone remains controversial. Interactions between receptor activator of NF-κB (RANK) and its ligand (RANKL) are required for osteoclastogenesis. The binding of RANK and RANKL induces differentiation of osteoclasts, leading to bony destruction. Osteoprotegerin (OPG), a decoy receptor for RANKL, also binds to RANKL by competing with RANK, and this could protect against osseous destruction. Materials and methods: Immunoexpression of RANKL, RANK, and OPG in 25 cases of human buccal SCCs without bony invasion and 15 cases of gingival SCCs with mandibular bony invasion was investigated. Normal oral mucosa from five individuals without betel-quid chewing or cigarette smoking was used as a control. The scores are designated as percentage of positive staining × intensity of staining for each section. Results: Strong cytoplasmic staining of RANKL proteins is detected in cancer cells of both buccal and gingival SCCs. The same protein is identified in cytoplasm of osteoclasts for all cases involving bony invasion. Strong cytoplasmic staining of RANKL is confined to basal layer for all normal mucosa. A similar staining pattern is noted for RANK protein in all buccal and gingival SCCs. An absence of staining of RANK protein is noted for all normal tissues. Weak to negative cytoplasmic stained OPG protein is present in all buccal and gingival SCCs, but is absent in all normal tissues. Conclusion: These findings suggest the potential value of the RANK/RANKL/OPG pathway as biomarkers in human oral SCCs. [ABSTRACT FROM AUTHOR]

In this study, an advanced supercritical fluid (SCF) technique that is suitable for materials and electronic devices with low temperature (80 °C) and high pressure (4000 psi) is proposed for a ZnO-based resistive random access memory (RRAM). After an SCF treatment, X-ray photoelectron spectroscopy (XPS) analysis confirms that the concentration of oxygen ions increases in the zinc oxide thin film. Moreover, electrical measurements confirm that the treated ZnO-based random access memory exhibits a lower forming voltage, lower set voltage, and higher ratio of high and low resistance states compared with a device without treatment. Next, the carrier transport mechanism is investigated by fitting the current–voltage curves. Finally, physical models are introduced to illustrate the extra oxygen ions that create better memory characteristics in the random access memory device after the SCF treatment. This significant SCF technique increases the content of oxygen ions without altering the original element ratio and maintains a simple device structure. Thus, the technique shows potential for feasible material improvement capable of effective real applications in the near future. [ABSTRACT FROM AUTHOR]

The HfZrOx (HZO) ferroelectric material is a promising material for ferroelectric memory and is compatible with the semiconductor process for ferroelectric random access memory (FeRAM) and negative capacitance field effect transistor. However, defects often exist in the grain boundary to influence the performance or reliability of devices. In addition, uniformity between devices must be considered when they are mass-produced. Therefore, the grain size will become important in determining the performance and reliability. In this study, we use electrical measurements of current–voltage, capacitance–voltage, and polarization–voltage measurements to test high- and low-temperature deposition devices, with a transmission electron microscope (TEM) image to confirm the grain size. Finally, we propose a model to explain the phenomenon and provide a method to obtain better ferroelectric memory. [ABSTRACT FROM AUTHOR]

This paper studies a composite device composed of ferroelectric random access memory (FeRAM) and metal-oxide-semiconductor field effect transistor. The relationship between the hysteresis characteristics and VG is reported, and the on/off ratios under different writing voltages are presented. The gm–VG curve of the forward and reverse sweeping shows that under forward sweep a very clear instability appears while voltage increases. The reasons for this can be explained according to the voltage divider rule, the ID formula, and gm formula of transistors, which show that there is polarization of the ferroelectric material. Accordingly, a method is proposed to determine the critical point of the ferroelectric capacitor polarization in this 1T1C structure, which is advantageous because it identifies the appropriate reading voltage necessary for an effective program state of the 1T1C device. This method was shown in three 1T1C and three FeRAMs devices with different ferroelectric areas. Finally, this method was verified by the P–V loop of FeRAMs. [ABSTRACT FROM AUTHOR]

This research investigates a novel supercritical-fluid sulfuration (SCF-S) treatment used to enhance the sensitivity of SnO 2 -based chip-typed gas sensors and enable them to resist the influence of moisture during the alcohol detection. The fluid of supercritical state possesses helpful features, such as high permeability of gas and high solubility of water. The SCF-S process introduces the sulfuration penetrating the whole tin oxide membrane with sulfur bonding and thin film transformation. The surface morphology and the lattice structure have been confirmed by Scanning Electron Microscope (SEM) and X-ray diffraction analysis (XRD), respectively. To further verify the composition content after the novel SCF-S treatment, the qualitative and quantitative analyses are conducted, and both show the sulfur doping results. Moreover, different electronic properties are gained in the experiments where the concentration of alcohol and environment humidity vary. In order to understand the sensing reaction model after SCF treatment, response performance at different temperatures and the reliability of the reaction model are further investigated. From the present results, it is demonstrated that SCF-S process has a good potential in terms of the sensitive and selective detection of alcohol. ● The sulfuration treatment helps to enhance sensitivity of SnO 2 -based gas sensors. ● Sensors treated with sulfuration treatment can operate with low working temperature. ● The treated SnO 2 sensor has high selectivity to alcohol molecule and moisture. ● The treated gas sensor is completely unaffected with humidity. ● Related reaction model is also built to illustrate the SCF sulfuration improvement. [ABSTRACT FROM AUTHOR]

In this research, the forming-free CBRAM is realized by high pressure hydrogen annealing method (HPHA). With the structure of Cu/HfO2/TiN, the copper will be ionized by the hydrogen ion under the high pressure environment; meanwhile the copper ion will diffuse to the HfO2. Thus, the diffused copper ion can earlier form the precursor seed to generate the filament because of short migration distance. Besides, the characteristic of CBRAM is also improved, which can be explained by the experimental result and the proposed model. [ABSTRACT FROM AUTHOR]

Polysaccharides-based membranes of chitosan and cellulose blends were prepared using trifluoroacetic acid as a co-solvent. Morphology and mechanical property of prepared membranes were studied by Instron and dynamic mechanical thermal analysis. The mechanical and dynamic mechanical thermal properties of the cellulose/chitosan blends appear to be dominated by cellulose, suggests that cellulose/chitosan blends were not well miscible. It is believed that the intermolecular hydrogen bonding of cellulose is supposed to be break down to form cellulose–chitosan hydrogen bonding; however, the intra-molecular and intra-strand hydrogen bonds hold the network flat. The reduced water vapor transpiration rate through the chitosan/cellulose membranes indicates that the membranes used as a wound dressing may prevent wound from excessive dehydration. The chitosan/cellulose blend membranes demonstrate effective antimicrobial capability against Escherichia coli and Staphylococcus aureus, as examined by the antimicrobial test. These results indicate that the chitosan/cellulose blend membranes may be suitable to be used as a wound dressing with antibacterial properties. [Copyright &y& Elsevier]