硅烷偶联剂对高密度聚乙烯薄膜/杨木胶合板性能的影响

采用硅烷偶联剂乙烯基三甲氧基硅烷(A-171)对杨木单板进行预处理,然后与高密度聚乙烯(HDPE)薄膜复合制备胶合板。研究了A-171对板材物理力学性能的影响,利用红外光谱、X射线光电子能谱及扫描电镜探讨了界面增容的机理。结果表明,经过A-171处理后,板材的胶合强度和耐水性都有所改善,当偶联剂用量为2%时处理效果最好,胶合强度达到1.8MPa,比未处理材的胶合强度增加128%,木破率也由10%提高到99%。胶合板的24h吸水率(WA)和吸水厚度膨胀率(TS)分别降低了28%和42%。通过X射线光电子能谱、红外光谱和扫描电镜分析可知,A-171成功在杨木单板表面发生了接枝反应,有效地改善了单板与HDPE的界面相容性。     

κ-卡拉胶凝胶的力学行为研究

利用溶胀性能自动检测仪,通过测定κ-卡拉胶(KC)凝胶的压缩形变及相应的应力得到其压缩模量Ee,并考察了介质(水、硅油和空气)、交联度和KC浓度对Ee的影响.结果表明,Ee值较小,仅在104 Pa数量级,并随KC浓度增加而增大;Ee对介质环境十分敏感,按在水、硅油及空气中的顺序递减;Ee与交联度关系更依赖于介质:在空气中基本成正比,在硅油中高交联度端略偏离直线,而在水中因高交联度端Ee下降而出现峰值."偏离"与"峰值"是典型软质材料的体现,与Ee值较小相符,并有凝胶溶胀程度愈大,软质材料特性愈明显的规律.     

浸蚀多孔铝模板制备TiO2亲水薄膜材料

利用浸蚀多孔铝模板,涂覆TiO2溶胶和纳米粉组成的料浆,制得TiO2亲水性阵列薄膜。通过对此薄膜SEM及表面接触角分析,研究了聚乙二醇改性、存放时间、SiO2的添加等对其亲水性的影响。结果表明:浸蚀多孔铝模板制备的TiO2薄膜无需紫外光激发即表现出良好的亲水性,5s内可达到完全铺展;料浆中添加0.02～0.04g/mL聚乙二醇能一定程度上提高薄膜材料亲水性并减缓其亲水性的降低;添加纳米SiO2制备的TiO2/SiO2复合薄膜亲水性优于纯TiO2薄膜,经聚乙二醇改性后为超亲水性,超亲水性能在黑暗中维持5天。     

碳钢磷化膜形成过程的研究

研究了高温锰系磷化膜在45#钢上的生长过程.分别用SEM和XRD观察和分析了磷化膜的表面形貌和成分,测量了磷化膜膜重随时间变化的关系.结果表明:磷化膜的晶体颗粒为块状,主要成分是(MnFe)5 H2·(PO4)4·4H2O,磷化的成膜时间是1 min.     

Giant Enhancements of Perpendicular Magnetic Anisotropy and Spin‐Orbit Torque by a MoS2 Layer

2D transition metal dichalcogenides have attracted much attention in the field of spintronics due to their rich spin‐dependent properties. The promise of highly compact and low‐energy‐consumption spin‐orbit torque (SOT) devices motivates the search for structures and materials that can satisfy the requirements of giant perpendicular magnetic anisotropy (PMA) and large SOT simultaneously in SOT‐based magnetic memory. Here, it is demonstrated that PMA and SOT in a heavy metal/transition metal ferromagnet structure, Pt/[Co/Ni]₂, can be greatly enhanced by introducing a molybdenum disulfide (MoS₂) underlayer. According to first‐principles calculation and X‐ray absorption spectroscopy (XAS), the enhancement of the PMA is ascribed to the modification of the orbital hybridization at the interface of Pt/Co due to MoS₂. The enhancement of SOT by the role played by MoS₂ is explained, which is strongly supported by the identical behavior of SOT and PMA as a function of Pt thickness. This work provides new possibilities to integrate 2D materials into promising spintronics devices.     

In-fiber liquid-level probe based on Michelson interferometer via dual-mode elliptical multilayer-core fiber

Abstract

An in-fiber liquid-level probe fabricated from homemade dual-mode elliptical multilayer-core fiber (EMCF) was proposed and experimentally demonstrated. The proposed sensor simply consists of a segment of the EMCF with one end coated with silver film, and a Michelson interferometer is roughly established when light from single-mode fiber incident from the other end. The detected interference patterns, rather clean due to the few-mode property, shift as the liquid level due to strong interaction between high-order modes and measurands through evanescent waves. Both the propagation characteristics and operation principle of such a sensor were demonstrated in detail, and sensitivities of 33.48, 43.35, and 48.93 pm/mm corresponding to liquid indices of 1.333, 1.353, and 1.373 were successfully achieved with a 50-mm EMCF probe, respectively. Moreover, the proposed sensor had the potential to discriminate measurand index after proper calibration.     

One step synthesis process for fabricating NiFe2O4 nanoparticle loaded porous carbon spheres by ultrasonic spray pyrolysis

In the present work, the porous hollow carbon spheres loaded with NiFe₂O₄ nanoparticles have been successfully prepared via ultrasonic spray pyrolysis technique at 700?°C and the associated formation mechanism has been studied. The as-prepared NiFe₂O₄/carbon microspheres with the diameter of about 3–5?µm and the specific surface area of 236.6889?m²?g^?1 exhibit good monodispersity and an abundance of mesopores of about 40?nm size. Notably, the 20?nm NiFe₂O₄ nanoparticles are encapsulated by carbon microspheres and disperse homogeneously inside the carbon matrix. We could tune the relative content of ferrite and carbon sphere via adjusting the composition of the solution used for synthesis and the carbonization temperature. Consequently, some interesting properties can be obtained by combining the magnetic NiFe₂O₄ nano powder and the electrically conductive porous carbon, which renders the resulting composite suitable for promising applications in electromagnetic wave absorption, treatment of polluted water, catalyst design, energy storage, batteries and so on.     

基于矩阵理论的动态防伪包装研究

主要阐述了可变图形在防伪包装设计中的应用。即采用计算机辅助生成技术,将若干独立的图形,经过矩阵加密排列运算,生成不重复的海量图形组合,能够通过无版印刷制作出防伪标签,并可通过短信及网站查询。对打击假冒伪劣产品,保护企业、国家和消费者的利益,具有重要的意义。     

酚醛树脂基泡沫炭的发泡行为及其孔结构控制

结合热塑性酚醛树脂的热失重和粘-温特性,研究了升温速率对其发泡行为及泡沫炭力学性能的影响。结果表明,热塑性酚醛树脂的发泡温区在200~300℃,并遵循热点成核发泡机制;300~600℃温区中产生的裂解气主要影响气泡的膨胀速度,进而影响泡沫炭的孔径及孔结构的均一性;以0.5℃/min升至240℃,再以3℃/min升至600℃,所制泡沫炭孔结构较为均一,其平均孔径、密度及压缩强度分别为300μm、0.51 g/cm~3和12.5 MPa。     

High-performance carbon nanotube light-emitting diodes with asymmetric contacts

Electroluminescence (EL) measurements are carried out on a two-terminal carbon nanotube (CNT) based light-emitting diode (LED). This two-terminal device is composed of an asymmetrically contacted semiconducting single-walled carbon nanotube (SWCNT). On the one end the SWCNT is contacted with Sc and on the other end with Pd. At large forward bias, with the Sc contact being grounded, electrons can be injected barrier-free into the conduction band of the SWCNT from the Sc contact and holes be injected into the valence band from the Pd electrode. The injected electrons and holes recombine radiatively in the SWCNT channel yielding a narrowly peaked emission peak with a full width at half-maximum of about 30 meV. Detailed EL spectroscopy measurements show that the emission is excitons dominated process, showing little overlap with that associated with the continuum states. The performance of the LED is compared with that based on a three-terminal field-effect transistor (FET) that is fabricated on the same SWCNT. The conversion efficiency of the two-terminal diode is shown to be more than three times higher than that of the FET based device, and the emission peak of the LED is much narrower and operation voltage is lower.