安规测试仪用于塑料制品探伤检测

该文介绍了传统的超声波、渗透和射线等绝缘体探伤方法,分析了它们的优缺点,针对其缺点,提出了用安规测试仪探伤塑料制品的方法。实验中,设置安规测试仪为拉弧停止,试验检测合格品的最高耐受电压,高压扫描塑料制品,筛选出不合格品。其过程简单、高效、快速、准确而且经济适用,可以通过改造测试探头适应不同的塑料制品,能取得不错的检测效果。     

Distribution of Living Ray Parenchyma Cells and Major Bioactive Compounds During the Heartwood Formation of Taiwania cryptomerioides Hayata

The heartwood of Taiwania (Taiwania cryptomerioides Hayata) has the excellent decay resistance and fascinating color qualities due to the accumulation of bioactive compounds. However, limited information was addressed to the heartwood formation of this species. In this study, we established the distribution of the living ray parenchyma cells and profiled the major bioactive compounds across and along the Taiwania stem. The ray parenchyma cells would die within 1–2 annual rings of the transition zone, which occurs around 8–13 annual rings counted from the cambium. The gradual loss of the starch grains accompanied with the deposition of the colored materials into the cell lumens started from the outer transition zone. The radial distribution of the extractive contents and its signature bioactive compounds across Taiwania stems gradually increased from the transition zone toward the heartwood tissues. The aforementioned properties did not show specific trends along the vertical direction of the Taiwania stems.     

Matrix influence on the piezoelectric properties of piezoelectric ceramic/polymer composite exhibiting particle alignment

This study was addressed to the influence of an electric field strength applied at fabrication process and matrix properties, such as the dielectric constant and the Young's modulus, on “pseudo‐1‐3 piezoelectric ceramic/polymer composite” in order to further enhance the piezoelectricity of that. The pseudo‐1‐3 piezoelectric ceramic/polymer composite consists of linearly ordered piezoelectric ceramic particles in polymer material. Silicone gel, silicone rubber, urethane rubber, and poly‐methyl‐methacrylate, which exhibit different dielectric constants and Young's modulus, were used as matrices to evaluate the matrix influence. The piezoelectricity of the pseudo‐1‐3 piezoelectric ceramic/polymer composite was evaluated using the piezoelectric strain constant d₃₃. The d₃₃ is one of the indices of the piezoelectric properties for piezoelectric materials. As a result, it was confirmed that d₃₃ of the pseudo‐1‐3 piezoelectric ceramic/polymer composite increased with the increase of the electric filed strength applied at fabrication process, though, it reached a constant value at a certain strength value. Further it was confirmed that dielectric constant of the matrix had a small influence on d₃₃ of the pseudo‐1‐3 piezoelectric ceramic/polymer composite, however, in case of matrix of lower Young's modulus, d₃₃ was increase. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41817.     

Electrical Breakdown Properties and Space Charge Formation in High Temperature Region in Ultraviolet Ray Irradiated PVC

Polyvinyl chloride (PVC) is the most popular insulating material for electric wiring instruments. However, an exothermic reaction above 150 °C may cause deterioration of the insulating properties of PVC. Therefore, it is important to clarify the heat degradation in PVC, not only to investigate the ignition of electrical wiring products but also to use electrical products safely. It is known that ultraviolet (UV) irradiation causes chemical deterioration of PVC and an increase in its conductivity. Generally, it has been thought that the electrical breakdown properties, electrical conduction, and insulating performance are affected by space charge accumulation in an insulating material. A high temperature pulsed electroacoustic (PEA) system usable up to 250 °C has been developed, and the PEA system can measure the space charge distribution and conduction current in the high temperature range simultaneously. In this investigation, the space charge distribution and conduction current were measured up to electrical breakdown in a non‐UV irradiated sample (normal PVC) and in 353 nm and 253 nm UV‐irradiated PVC samples in the range from room temperature to 200 °C in a DC electric field. In the short wavelength UV irradiated PVC sample (253 nm, 300 h), a deterioration of breakdown strength at 90 °C to 150 °C and negative packet‐like charges were observed at 60 °C and 100 °C, a positive charge accumulated in front of both the anode and cathode above 90 °C, and a higher electric field near the cathode side because the positive charge of the cathode side was greater.     

Graphite Oxide and Aromatic Amines: Size Matters

Experimental and theoretical studies are performed in order to illuminate, for first time, the intercalation mechanism of polycyclic aromatic molecules into graphite oxide. Two representative molecules of this family, aniline and naphthalene amine are investigated. After intercalation, aniline molecules prefer to covalently connect to the graphene oxide matrix via chemical grafting, while napthalene amine molecules bind with the graphene oxide surface through π–π interactions. The presence of intercalated aromatic molecules between the graphene oxide layers is demonstrated by X‐ray diffraction, while the type of interaction between graphene oxide and polycyclic organic molecules is elucidated by X‐ray photoelectron spectroscopy. Combined quantum mechanical and molecular mechanical calculations describe the intercalation mechanism and the aniline grafting, rationalizing the experimental data. The present work opens new perspectives for the interaction of various aromatic molecules with graphite oxide and the so‐called “intercalation chemistry”.     

X射线干涉光刻光束线关键光学元件热-结构耦合分析

为了保证上海光源X射线干涉光刻光束线的稳定性,减小热变形对实验结果的影响,对X射线干涉光刻光束线的3个关键光学元件——偏转镜、聚焦镜和精密四刀狭缝进行热-结构耦合分析。首先,计算偏转镜、聚焦镜和精密四刀狭缝所承载的功率密度;然后,建立其有限元模型;最后,获得光学元件的温度场和热变形的结果。结果表明,偏转镜和聚焦镜采用间接水冷方式可有效抑制热变形,冷却后的最大面形误差分别为7.2μrad和9.2μrad。精密四刀狭缝未冷却时,刀片组件温度介于271.56~273.27℃,刀口热变形为0.19 mm,直线导轨热变形为0.08 mm;经过铜辫子冷却后,刀片组件温度降至22.24~23.94℃,刀口热变形降至0.2μm,直线导轨热变形降至0.1μm;采用影像法和接触探头法测试后,刀口直线度、平行度和重复精度均满足技术要求。偏转镜、聚焦镜和精密四刀狭缝的热变形通过间接水冷和铜辫子的冷却方式可以得到很大程度的抑制,进而保证光斑质量。     

Damage evolution around white etching layer during uniaxial loading

Rolling contact fatigue cracks and thermally induced defects are common problems in the railway industry especially as demands for increasing loads, speeds, and safety continue to rise. Often, the two types of defects are found together in the field, however, whether one causes the other to occur is not completely agreed upon. The effect of thermal damage, in the form of a martensite spot on pearlitic steel test bars, on the fatigue life in uniaxial low cycle fatigue experiments was investigated by the authors. However, the focus of the current work was to characterize the damage evolution from the low cycle fatigue (LCF) tests and correlate the crack initiation and propagation with the initial thermal damage. Residual stress measurements, digital image correlation, and X‐ray tomography were used to characterize the effects of the thermal damage before, during, and after fatigue testing, respectively. It was found that the thermal damage causes strain accumulation and crack initiation at the interface between the two materials. The strain evolution was visualized using digital image correlation (DIC), clearly showing the strain concentrations at the top and bottom of the white etching layers (WEL), where the residual stresses are also most tensile. X‐ray tomography confirmed the planar crack growth from the martensite spot.     

数字化射线检测技术在船舶领域的应用

随着数字射线检测技术的不断发展,CR与DR数字射线检测技术以其检测灵敏度高、检测速度快及底片数据电子化存储等优势越来越广泛地应用于各行业中。针对船舶行业射线检测的主要检测对象(钢板对接焊缝、管路对接焊缝),开展了CR数字射线检测技术等价性评价、典型裂纹试验,以及基于不同种类射线装置的DR数字射线检测工艺试验,验证了数字化射线检测技术在船舶领域应用的适用性。