Effects of hydrogen plasma treatment on the physical and chemical properties of tin oxide thin films for ambipolar thin-film transistor applications

In this study, we investigated the physical and chemical properties of H₂ plasma-treated tin oxide (SnO_X) thin films, followed by their applications in ambipolar thin-film transistors (TFTs). Finely controlled H₂ implantation was carried out using a reactive-ion-etching system at a radio frequency power of 30 W and under various exposure times. H₂ plasma treatments induced changes in the chemical structures and surface morphologies of the SnO_X thin films, including a partial phase transformation of Sn and SnO to SnO₂. The defects originating from oxygen vacancies (O_Vacs) in the SnO_X thin films were passivated by H via the formation of Sn–H bonds, which decreased the density of subgap states in the SnO_X thin films. The H₂ plasma-treated SnO_X TFTs showed considerably improved ambipolarity and electrical performance. Complementary metal–oxide–semiconductor (CMOS) logic inverters comprising H₂-plasma-treated ambipolar SnO_X TFTs exhibited a maximum gain of 34.5 V/V at a supply voltage of 10 V. The results of this study present the meaningful investigation of H₂ plasma-treated ambipolar SnO_X TFTs that can be used to fabricate CMOS circuits for various applications.     

Molecular design for thermally stable SiZrBOC structure from single source precursor with high ceramic yield

A new type of high-temperature-resistant SiZrBOC ceramics was prepared by sol-gel method using polymethyl-hydro siloxane (PMHS), boric acid (B(OH)₃), and n-propyl zirconate (Zr(OPr)₄) as raw materials. After high-temperature pyrolysis, the SiZrBOC precursor was transformed into a crystalline ceramic material with a yield of 89.5 wt%. Fourier infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA) were applied to characterize the polymer-ceramic conversion process and thermal behavior of ceramic precursors. According to the results, the addition of boron elements led to the formation of Si-O-B links in the system. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to study the phase composition and microstructure of SiZrBOC ceramics. Finally, the oxidation test at 1200 °C revealed that SiZrBOC ceramics with a boron/zirconium molar ratio of 2.5:1 exhibited the best oxidation resistance at a weight gain of 0.4 wt% only.     

Meal patterns of weaned dairy calves are affected by previous dietary experience and associated with competition surrounding individual feed bins

The objective of this study was to evaluate how meal patterns of recently weaned and group-housed dairy calves are subject to effects of previous dietary experience and associated with competition for feed. During the preweaning period, Holstein heifer and bull calves were provided diets differing in provision and presentation of forage as follows: (1) pelleted starter only (n = 12), (2) starter and chopped coastal bermudagrass provided in separate buckets (n = 13), (3) starter and chopped coastal bermudagrass mixed together in the same bucket (n = 15), or (4) starter, chopped coastal bermudagrass, and liquid molasses mixed together in 1 bucket (n = 13). At 58 ± 2 (mean ± standard deviation) days of age, following weaning, calves were mingled between treatments and moved into group housing in weekly age-based cohorts (7 ± 2 calves/group; 8 groups total), and all were provided the mixed diet (without molasses). Within group pens, calves were fed individually using the Calan Broadbent feeding system (American Calan Inc.). Calves were monitored for 1 wk following introduction to the group pen. Feed intake was measured daily. Behavioral data, describing feeding times and competition for feed, were recorded continuously for 48 h beginning after a 5-d adaptation to the group pen. Calves previously provided starter only had longer, less frequent meals than calves previously provided forage in any form, and they tended to consume less feed compared with those previously provided starter and hay separately, with calves previously provided mixed diets having intermediate intakes. We observed occurrences of displacements at bins, which were followed by replacements and feed stealing on some occasions, where 34% of calves consumed feed from a bin assigned to another calf on at least 1 occurrence, and 64% of calves were stolen from at least once. Competition at feed bins was not affected by previous dietary treatments, but was associated with meal patterns. Actor displacement rate was negatively associated with meal frequency and duration, but calves that were displaced more often were those that spent more time feeding. These results suggested a possible carryover effect of previous exposure to forage on postweaning meal patterns following a dietary change. Further, we found that competitive behavior varied considerably between individuals, occurring frequently despite feeding calves using individually-assigned feeding bins, and was associated with meal characteristics. These results highlighted the importance of considering both previous dietary experience and social factors when evaluating feeding behavior.     

Experimental study on the deformation and failure mechanism of overburden rock during coal mining using a comprehensive intelligent sensing method

Understanding the spatiotemporal evolution of overburden deformation during coal mining is still a challenge in engineering practice due to the limitation of monitoring techniques. Taking the Yangliu Coal Mine as an example, a similarity model test was designed and conducted to investigate the deformation and failure mechanism of overlying rocks in this study. Distributed fiber optic sensing (DFOS), high-density electrical resistivity tomography (HD-ERT) and close-range photogrammetry (CRP) technologies were used in the test for comprehensive analyses. The combined use of the three methods facilitates the investigation of the spatiotemporal evolution characteristics of overburden deformation, showing that the mining-induced deformation of overburden strata was a dynamic evolution process. This process was accompanied by the formation, propagation, closure and redevelopment of separation cracks. Moreover, the key rock stratum with high strength and high-quality lithology played a crucial role in the whole process of overburden deformation. There were generally three failure modes of overburden rock layers, including bending and tension, overall shearing, and shearing and sliding. Shear failure often leads to overburden falling off in blocks, which poses a serious threat to mining safety. Therefore, real-time and accurate monitoring of overburden deformation is of great significance for the safe mining of underground coal seams.     

高面板坝全寿命周期变形控制方法及应用

高面板坝的变形对面板的安全运行有着特别重要的影响，国内外已建的高面板坝工程中，因坝体变形大导致防渗面板挤压破损，坝体渗漏量大的实例较多，不得不降低水库水位进行修复处理，造成较大的经济损失乃至给大坝的长期运行留下安全隐患。通过发生挤压破损的实例分析，发现变形控制缺乏系统性是发生面板挤压破损的主要因素，为预防面板破损，系统提出了“控制坝体总变形，转化有害变形，适应纵向变形”的坝体变形控制方法，并在使用软硬岩混合料筑坝的董箐面板堆石坝中得到的应用，取得了良好效果，该工程运行至今达十余年，未见面板有挤压破损迹象，该方法对建设200 m以上乃至300 m级超高面板坝具有重要借鉴意义。     

The structure,vacancy characteristics,and magnetic properties of GdMn1-xCrxO3 ceramics

To investigate the evolution of the structural and enhanced magnetic properties of GdMnO₃ systems induced by the substitution of Mn with Cr, polycrystalline GdMn_1-xCr_xO₃ samples were synthesized via solid-state reactions. XRD characterization shows that all GdMn_1-xCr_xO₃ compounds with single-phase structures crystallize well and that Cr³⁺ ions entering the lattice sites of GdMnO₃ induce structural distortion. SEM results indicate that the grain size of the synthesized samples (a few microns) decreases as the Cr substitution concentration increases. Positron annihilation lifetime spectroscopy reveals that vacancy-type defects occur in GdMn_1-xCr_xO₃ ceramics and that the vacancy size and concentration clearly change with the Cr content. The temperature and field dependence of the magnetization curves show that Cr substitution significantly influences the magnetic ordering of the gadolinium sublattice, improving the weak ferromagnetic transition temperature and magnetization of GdMn_1-xCr_xO₃. The enhanced magnetization of GdMn_1-xCr_xO₃ is closely related to the vacancy defect concentration.     

Non-additive sintering of Si2N2O ceramic with enhanced high-temperature strength,oxidation resistance,and dielectric properties

The high-temperature mechanical and dielectric properties of Si₂N₂O ceramics are often limited by the introduction of a sintering aid. Herein, dense Si₂N₂O was prepared at 1700 °C by hot-pressing oxidized amorphous Si₃N₄ powder without sintering additives. A homogeneous network with short-range order and a SiN₃O structure was formed in the oxidized amorphous Si₃N₄ powder during the hot-pressing process. Si₂N₂O crystals preferentially nucleated at positions within the SiN₃O structure and grew into rod-like and plate-like grains. Fully dense ceramics with mainly crystalline Si₂N₂O and some residual amorphous phases were obtained. The as-prepared Si₂N₂O possessed a good flexural strength of 311 ± 14.9 MPa at 1400 °C, oxidation resistance at 1500 °C, and a low dielectric loss tangent of less than 5 × 10⁻³ at 1000 °C.     

High energy storage and ultrafast discharge in NaNbO3-based lead-free dielectric capacitors via a relaxor strategy

Dielectric capacitors with decent energy storage and fast charge-discharge performances are essential in advanced pulsed power systems. In this study, novel ceramics (1-x)NaNbO₃-xBi(Ni_2/3Nb_1/3)O₃(xBNN, x = 0.05, 0.1, 0.15 and 0.20) with high energy storage capability, large power density and ultrafast discharge speed were designed and prepared. The impedance analysis proves that the introducing an appropriate amount of Bi(Ni_0·5Nb_0.5)O₃ boosts the insulation ability, thus obtaining a high breakdown strength (E_b) of 440 kV/cm in xBNN ceramics. A high energy storage density (W_total) of 4.09 J/cm³, recoverable energy storage density (W_rec) of 3.31 J/cm³, and efficiency (η) of 80.9% were attained in the 0.15BNN ceramics. Furthermore, frequency and temperature stability (fluctuations of W_rec ≤ 0.4% over 5–100 Hz and W_rec ≤ 12.3% over 20–120 °C) were also observed. The 0.15BNN ceramics exhibited a large power density (19 MW/cm³) and ultrafast discharge time (~37 ns) over the range of ambient temperature to 120 °C. These enhanced performances may be attributed to the improved breakdown strength and relaxor behavior through the incorporation of BNN. In conclusion, these findings indicate that 0.15BNN ceramics may serve as promising materials for pulsed power systems.     

Precipitous weakening of quartz at the α–β phase inversion

Crystalline quartz has long been identified as among the weakest of abundant crustal minerals. This weakness is particularly evident around the α–β phase inversion at 573°C, in which Si–O bonds undergo a displacive structural transformation from trigonal to hexagonal symmetry. Here we present data using indentation testing methodologies that highlight the precipitous extent of the transformational weakening. Although the indentations are localized over relatively small specimen contact areas, the data quantify the essential deformation and fracture properties of quartz in a predominantly (but not exclusively) compressive stress field, at temperatures and pressures pertinent to conditions in the earth's crust.     

Ion migration behavior and its interaction with sintering environment in cation conductor during flash sintering

Flash sintering has been reported in various ceramics. Nevertheless, anion and cation conductors exhibit different flash-sintering behaviors, and the interaction mechanism between the conductive species and the sintering environment has remained unclear. Herein, we report the flash-sintering phenomena of a typical cation conductor, Na₃Zr₂(SiO₄)₂(PO₄) with anode region surrounded by air and NaNO₃ environments. The results prove that the ionic behavior and joule heating distribution can be controlled by changing the electrode environment. Four possible scenarios describing the ion migration behavior and interaction with the environment are proposed for providing a guidance for controlling the ion interaction behavior during flash sintering.