碳化硅对莫来石-铝矾土浇注料力学性能的影响

以莫来石、铝矾土为主要原料,铝酸钙水泥为结合系统,分别研究了不同碳化硅含量经过不同热处理温度后对莫来石-铝矾土浇注料性能的影响。试样自然干燥24 h脱模后,再经110℃烘干24 h,在空气中分别于1000℃、1300℃和1500℃热处理3 h。检测各种温度热处理后试样的线变化率、抗折强度、耐压强度和耐磨性能。结果表明,当ω(碳化硅)=10%时,莫来石-铝矾土浇注料经过1000℃和1300℃热处理后的线收缩率出现最小值。由于热处理过程中形成的适量SiO2液相有助于浇注料表面防氧化薄膜的形成,提高了材料的抗氧化性能,防止碳化硅的进一步氧化,保护了碳化硅材料,增大了材料的强度。在本实验条件下,SiC加入量为ω(碳化硅)=10%时,浇注料的力学性能最好。     

Numerical assessment for impact strength measurements in concrete materials

Measurement of dynamic strength of concrete at impact relevant strain rates and pressures is the purpose of the described study. Therefore, an experimental design of direct planar impact experiments with longitudinal and transverse strain gauges is analyzed in predictive hydrocode simulations using an elastic–plastic damage model for concrete. The calculations and first experimental results on mortar show decreasing phase velocities of stress waves both in longitudinal and lateral gauges. The model clearly associates it with the onset of damage, possibly interpreted as a failure wave. Numerical analysis is furthermore used to compare a monolithic target block to a thoroughly assembled concrete sample in order to include flat gauges in the material. The planned experimental procedure to derive wave speeds, particle velocities and strain rates from stress measurements is anticipated and validated on the basis of simulated gauge signals. The most important finding is the prediction and first experimental confirmation that concrete ultimate strength and damaged yield stress can be derived at strain rates in the order of 10⁴/s from the proposed type of experiments. This technique promises new insight into the strength and failure processes of concrete in the challenging loading region around the characteristic minimum of the shock particle velocity relationship.     

Effect of oxygen plasma treatment on bonding states for columnar structured a-CNx thin films prepared by reactive sputtering

Amorphous carbon nitride (a-CN) thin films were deposited on silicon single crystal substrates by rf-reactive sputtering method using a graphite target and nitrogen gas. The substrate temperature was varied from room temperature (RT) to 853 K. After deposition, the effect of oxygen plasma treatment on bonding structures of the film surface has been studied by using an oxygen discharge at 16 Pa and rf power of 85 W. The chemical bonding states and film composition were analyzed by X-ray photoelectron spectroscopy (XPS), while film thickness was obtained from scanning electron microscopy (SEM) and ellipsometer. XPS study revealed that the films have NO₂ and NO₃ bonding structures when the films are deposited at temperatures higher than 673 K. After exposure to oxygen plasma, carbon in the film surface was etched selectively and this phenomenon was observed in all films. In contrast, the surface concentration of nitrogen was ket at constant values before and after oxygen plasma treatment. The NO₃ bonding state had dramatically increased after oxygen plasma treatment for films deposited at higher deposition temperatures. The film surfaces have been observed to change the function from hydrophobic to hydrophilic after oxygen plasma treatment.     

Application of silicon polymer as positive photosensitive material

A new positive-working photosensitive system of silicon polymer, containing silylether groups in the main chain and a photo-induced acid precursor was investigated. The silicon polymer is hydrolized by a photogenerated acid and degraded to low molecular weight compounds. Thus the effect of solubility inhibition of the polymer is diminished. The higher photosensitivity of this system as compared with 1,2-quinone diazide compounds is due to the catalytic reaction of the acid on the hydrolysis of the silicon polymer. The chemical structure around silylether groups in the polymer, in particular more hydrophilic and less steric structures, affects the rate of hydrolysis and thus the photosensitivity. Among various types of photo-induced acid precursors examined, e.g., s-triazine and 1,3,4-oxadiazole compounds substituted by trihalomethyl groups were effective.     

Orbital lobe lacrimal ductal cyst

Lacrimal ductal cysts are rare, especially in the orbit. A case of lacrimal ductal cyst in the orbital lobe, revealed by computed tomography and magnetic resonance imaging, is described in a 16-year-old man who was successfully treated by complete surgical excision. The radiologic and clinical features of this type of lacrimal ductal cyst are discussed.     

A framework for simulation-optimization software

Research on the optimization of stochastic systems via simulation often centers on the development of algorithms for which global convergence can be guaranteed. On the other hand, commercial software applications that perform optimation via simulation typically employ search heuristics that have been successful in deterministic settings. Such search heuristics give up on global convergence in order to be more generally applicable and to yield rapid progress towards good solutions. Unfortunately, commercial applications do not always formally account for the randomness in simulation responses, meaning that their progress may be no better than a random search if the variability of the outputs is high. In addition, they do not provide statistical guarantees about the "goodness" of the final results. In practice, simulation studies often rely heavily on engineers who, in addition to developing the simulation model and generating the alternatives to be compared, must also perform the statistical analyses off-line. This is a time- and labor-consuming process. In this paper, we report on the work we have done to implement statistical error control within a heuristic search procedure, and on our automated procedure to deliver a statistical guarantee after the search procedure is finished. We describe how we implemented these techniques in software developed for JGC Corporation of Japan.     

Sustained Release Suppository of Sodium Diclofenac: use of Water Absorbable Polymer

The investigation on the usefulness of water absorbable polymer (Poys® SA-20) for the preparation of sustained release suppository was performed. To prepare the sustained release suppository, sodium diclofenac solution is absorbed into the sphere polymer, and the particles of the polymer after dryness are suspended in the melted triglyceride suppository base, followed by solidification. The sustained release of sodium diclofenac from the suppository was confirmed by the in vitro release study with slow release of sodium diclofenac and by the in vivo absorption study in dogs with an avoidance of transient high plasma diclofenac concentration and a prolong of plasma diclofenac concentration.     

High‐resolution and high‐brightness full‐colour “Silicon Display” for augmented and mixed reality

High‐brightness micro‐LED display bonded onto silicon backplane has been successfully demonstrated. The 0.38‐inch full‐colour active matrix LED microdisplay system consists of 352 × 198 pixels. Each pixel is 24 μm square composed of red, green, and blue (RGB) subpixels corresponding to a pixel resolution of 1053 ppi. Quantum‐dot materials are formed on III‐nitride blue micro‐LED array to convert blue light into red and green for full‐colour operation. We have confirmed that this microdisplay, which we call “Silicon Display” has wide colour gamut exceeding 120% of sRGB. We describe the advantage of this colour‐converting approach for the full‐colour micro‐LEDs. Progress toward higher resolution is also described. Brightness of more than 30 000 cd/m² has been confirmed at a driving current density of 4 A/cm² for 3000 ppi blue monochrome micro‐LED prepared for full‐colour Silicon Display. We believe our “Silicon Display” is ideally suited for near‐to‐eye displays for augmented and mixed reality.     

Region-of-interest visualization by CAVE VR system with automatic control of level-of-detail

To specify the region of interest (ROI) is an effective approach to visualize large scale simulation data. We have developed a three-dimensional visualization software with ROI function for the CAVE virtual reality systems. This software enables the user to perform fully three-dimensional and interactive visualization of large scale computational fluid dynamics (CFD) data. The user specifies a ROI in the CAVE room by a three-dimensional “mouse-drag”. The data in the specified ROI is automatically extracted from the original CFD data. This ROI procedure can be repeated recursively. The resolution in each ROI is kept approximately constant. A data set of three vector fields and eight scalar fields whose size is about 1 GB each was successfully analyzed.