Room-Temperature Solid-Matrix Luminescence Spectroscopy of Pyrene and 1-Hydroxypyrene from Optically Clear Sugar Glasses

Room-temperature solid-matrix luminescence was investigated for two model compounds pyrene and 1-hydroxypyrene from optically clear sugar glasses. Several glasses were investigated. Novel glasses were prepared for the first time from binary mixtures of sugars for spectroscopy. Glasses were prepared from glucose/xylose and glucose/maltose. The glucose/maltose gave a superior glass compared to glucose/xylose. The glucose/maltose glass gave the best room temperature phosphorescence (RTP) for pyrene compared to glasses of glucose and maltose without a heavy atom. The RTP was weak for both pyrene and 1-hydroxypyrene without a heavy atom in the glucose glass. The addition of a heavy atom (12% NaI) gave a 44-fold increase in RTP of pyrene and a 10-fold increase in the RTP of 1-hydroxypyrene. Room temperature fluorescence (RTF) of pyrene and 1-hydroxypyrene were easily observed from all the glass systems studied. However, the pyrene RTF intensity varied with the different sugar glass systems studied. Furthermore, a polymer, polyacrylic acid (PAA), was added to the sugar matrix at the level of 1% and 2% to improve the rigidity of the glass matrix. The observed phosphorescence was weak for pyrene at both the 1% and 2% PAA concentrations. A glass prepared with 2% PAA gave the strongest RTP for pyrene. Addition of 12% NaI with 1% polyacrylic acid did improve the RTP of pyrene but it was less than the RTP of pyrene from a glucose glass with 12% NaI by a factor of 2.7. A glucose glass with 12% NaI was the best system for RTP of pyrene.     

Enhanced conductivity of bacterial cellulose films reinforced with NH4I-doped graphene oxide

ABSTRACT

Bacterial cellulose (BC) films reinforced with reduced graphene oxide (RGO) platelets were investigated to assess their potential application as solid polymeric electrolytes. BC-RGO composites were further doped with NH₄I at different concentrations to evaluate the effect of NH₄I doping on the conductivity. Scanning electron microscopy images confirmed that GO addition did not alter BC coherent three-dimensional morphology. Electrochemical impedance spectroscopy studies revealed that the ionic conductivity increased with the ammonium iodide salt concentration. The highest conductivity found was 1.32 × 10^?4 S/cm for the samples doped with 5% NH₄I, suggesting that BC-RGO can be a promising candidate for electrochemical applications.     

Pretreatment of Rice Hulls for Cellulase Production by Solid Substrate Fermentation

Abstract

Rice hulls via pretreatment served as a solid substrate for cellulase production. Different pretreatment methods, including microwave irradiation, organosolv process catalyzed by acid or alkali were compared. With rice hulls pretreated by microwave irradiation coupled with alkaline pretreatment and rice hulls pretreated with organosolv process catalyzed with acid or alkali, the maxima of filter paper activity (FPA) obtained during the fermentation were 18%, 21%, 31% higher, and maxima of the carboxy‐methyl cellulase (CMCase) were 7.7%, 14%, 16% higher than those obtained with the rice hulls pretreated only with alkali, respectively. The ratios of cellulose degradation were also estimated and they showed similar tendency with the maxima of FPA detected in the fermentation processes.     

降补固态软启动装置在我公司的应用

大型高压电机的启动是一个令人棘手的问题。从启动方式的确定、启动装置的选型、降补固态软启动装置的特点、启动数据和效果评价等方面人手,介绍了甘肃刘化（集团）有限责任公司利用有限的供电系统容量启动大型高压电机的成功经验。     

一种复合型发泡剂ADC产品的研制

介绍一种有机固体为活化剂生产复合型发泡剂ADC产品方法,分析了复合型发泡剂ADC产品的生产技术,产品的发气量及分解温度与产品中活化剂成份比例关系等因素。     

片碱生产过程中的优化改进

本文主要阐述了新疆圣雄能源股份公司新建设一套国产化的片碱装置,在试车和生产过程中出现的问题及解决办法。     

Electrochemical performance of a mechanochemically prepared submicron-sized crystalline Nd1.8Ce0.2CuO4±δ cathode for intermediate temperature solid oxide fuel cells

To produce a Nd_1.8Ce_0.2CuO_4±δ solid solution, the oxide form of the reagents were milled for 36 h and sintered at 1173 K for 8 h in a microwave furnace. The transition from a negative temperature coefficient (NTC) of conductivity to a positive temperature coefficient (PTC) was suppressed due to the submicron size of the crystallites. The low-frequency response in the complex impedance plane fit the Gerischer element. At 973 K, the area specific resistance (ASR) of Nd_1.8Ce_0.2CuO_4±δ/GDC/Nd_1.8Ce_0.2CuO_4±δ sintered at 1073 K for 2 h was 1.92 ohm cm².     

Synthesis and hydrogen storage properties of Mg-based alloys

Mg-based alloys have been made by mechanical alloying Mg with some transition and non-transition elements. The thermal stability and hydrogen storage properties have been investigated. It was found that mechanical alloying results in a supersaturated solid solution of some elements in the Mg phase. Thermal annealing and/or hydrogenation cause irreversible decomposition of supersaturated solid solution leading to a composite of Mg or MgH₂ with other phase(s) depending on the composition and contents. Therefore, the plateau pressure or thermodynamic properties of hydrogen absorption/desorption of the supersaturated solid solution are no different from that of the Mg composite. While in some equilibrium systems, the formation of Mg solid solution is reversible upon hydrogenation/dehydrogenation. The plateau pressure of the hydrogenation/dehydrogenation is increased due to the interaction of the alloying elements with the Mg lattice in the solid solution. The Mg–Li system is an exception because of the formation of stable LiH upon hydrogenation of Mg(Li) solid solution. No interaction takes place between Mg or MgH₂ with LiH, therefore, no destabilization of MgH₂ is observed.     

GCr15钢微织构表面固体润滑性能研究

为研究不同表面处理方式对PTFE/GCr15钢配副表面摩擦学性能的影响,采用Nd:YAG纳秒激光器对GCr15轴承钢下试样表面进行激光织构加工,并以纳米MoS₂固体润滑剂作为润滑介质,以黏结有PTFE自润滑衬垫的圆柱销作为上试样进行对摩试验。研究发现:PTFE自润滑衬垫与微织构GCr15摩擦副在干摩擦条件下摩擦因数较低,仅为0.137,而在纳米MoS₂固体润滑剂润滑条件下,其摩擦因数进一步下降为0.123,且波动较小。通过EDS分析表明,表面微织构、聚四氟乙烯衬垫与纳米MoS₂润滑介质三者具有协同润滑减摩效应,可摩擦副表面生成一层由PTFE与纳米MoS₂材料组成的致密、平滑复合润滑膜,有效改善对摩副之间的润滑特性。研究表明,通过表面激光织构技术与固体自润滑技术(添加纳米MoS₂)的有效集成融合,可进一步改善PTFE/GCr15钢配副的润滑性能。