桉烷倍半萜-7(11),8(9)-共轭双烯中间体的合成

二氢沉香呋喃倍半萜多羟基酯(结构如1)是从卫矛科植物中分离提取的主要成分.生物活性试验表明该类物质不仅具有许多重要的生理活性[1～2],而且还具有低毒的杀虫活性[3],有可能研究开发成一类新型的低毒杀虫剂.但是截止目前,有关这类多羟基化合物的合成方法极其复杂,需要近20个反应步骤[4].     

离子色谱法测定复杂氮硫化物

建立了复杂氮硫化物的离子色谱分析方法。在选定的色谱条件下能很好地分离多种高价及低价Ｎ－Ｓ化合物,尤其是能分析三价离子氨基三磺酸根。线性范围分别为：羟胺二磺酸根（０．０９８～６．９６０）×１０－４ｍｏｌ／Ｌ;氨基二磺酸根（０．１２５～１．５０９）×１０－４ｍｏｌ／Ｌ;氨基三磺酸根（０．３８０～３．０４６）×１０－４ｍｏｌ／Ｌ;羟胺一磺酸根（０．０２７～１．２４３）×１０－４ｍｏｌ／Ｌ;氨基一磺酸根（０．０１６～１．１６８）×１０－４ｍｏｌ／Ｌ。实验表明该法具有分析时间短、线性范围宽、灵敏和准确等优点     

Recent Development of Anion Exchange Membrane Fuel Cells and Performance Optimization Strategies: A Review

Anion exchange membrane fuel cells (AEMFCs) are the most promising low-temperature fuel cells and have received extensive attention. Compared to PEMFCs, the cost per unit of power can be significantly reduced for AEMFCs because, in theory, they allow the usage of non-precious metal catalysts and low-cost cell components. Owing to the development of advanced materials and performance improvement strategies, AEMFCs have achieved new records in both initial performance and durability. However, the high performance currently achieved is contingent on certain conditions, e. g., high Pt loading, large gas flowrates, and operation in pure O₂, which are far from practical applications. Therefore, the transition to commercially relevant performance and durability is the next goal of AEMFCs. This paper reviews the performance data of H₂-fueled AEMFCs since 2010 and summarizes possible performance optimization schemes, which can provide useful insights for developing next-generation AEMFCs.     

Aza-BODIPY molecular assembly at the liquid-solid interface driven by Br⋯FBF interactions

In this work, two aza-BODIPY derivatives, 3,5-diphenyl-1,7-di(p-dodecyloxyphenyl)-aza-BODIPY (CJF) and 3,5-di(p-bromophenyl-1,7-di(p-dodecyloxyphenyl)-aza-BODIPY (2Br-CJF) acted as model molecules to form the self-assembly monolayers on the solid-liquid interface. With the utilizing of scanning tunnelling microscope (STM), we demonstrated that intermolecular Br⋯FBF interactions existed in 2Br-CJF self-assembly structure and played an important role in strengthening the stability of 2Br-CJF self-assembly structure. This result is supported by density functional theory (DFT) calculation.     

高功率薄片激光介质温度与应力数值模拟

NdYAG薄片激光介质采用上表面二极管阵列泵浦,下表面冷却的工作方式,对NdYAG薄片激光介质和Cu冷却器建立了理论计算模型.分别计算了在不同泵浦面积的条件下薄片的温度分布和应力大小,薄片泵浦面积大小与应力的关系,以及在NdYAG薄片与Cu冷却器之间增加与NdYAG热膨胀系数相近的介质层材料对应力影响的关系.计算结果表明在泵浦功率密度、外界温度和冷却条件一致的情况下,泵浦光泵浦整个薄片时总体应力最小,应力主要是由于NdYAG薄片与Cu冷却器热膨胀系数不匹配而产生的,增加介质层能改变应力大小;泵浦光泵浦部分薄片时总体应力较大,应力主要是薄片泵浦区与非泵浦区温差造成的,与介质层无关.     

Analysis of current–voltage and capacitance–voltage characteristics of perylene-monoimide/n-Si Schottky contacts

The electrical and interface state properties of Au/perylene-monoimide (PMI)/n-Si Schottky barrier diode have been investigated by current–voltage (I–V) and capacitance–voltage (C–V) measurements at room temperature. A good rectifying behavior was seen from the I–V characteristics. The series resistance (R_s) values were determined from I–V and C–V characteristics and were found to be 160 Ω and 53 Ω, respectively. The barrier height (Φ_b) of Au/PMI/n-Si Schottky diode was found to be 0.694 eV (I–V) and 0.826 eV (C–V). The ideality factor (n) was obtained to be 4.27 from the forward bias I–V characteristics. The energy distribution of interface state density (N_ss) of the PMI-based structure was determined, and the energy values of N_ss were found in the range from E_c ? 0.508 eV to E_c ? 0.569 eV with the exponential growth from midgap toward the bottom of the conduction band. The values of the N_ss without R_s are 2.11 × 10¹² eV^?1 cm^?2 at E_c ? 0.508 eV and 2.00 × 10¹² eV^?1 cm^?2 at E_c ? 0.569 eV. Based on the above results, it is clear that modification of the interfacial potential barrier for metal/n-Si structures has been achieved using a thin interlayer of the perylene-monomide.     

GaAs多结电池宽光谱ZnS/Al2O3/MgF2减反射膜的设计与分析

 为了提高砷化镓(GaAs)多结太阳电池的光电转换效率,设计了宽光谱(300 nm～1 800 nm)ZnS/Al2O3/MgF2三层减反射膜,分析了各层的厚度及折射率对三层膜系有效反射率的影响。结果表明： 对于整个波长,ZnS厚度对有效反射率的影响要大于Al2O3和MgF2,MgF2厚度对有效反射率的影响最小;适当减小MgF2的折射率或增加ZnS的折射率可得到更低的有效反射率。同时,当 ZnS,Al2O3和MgF2的最优物理厚度分别为52.77 nm,82.61 nm,125.17 nm时,此时最小有效反射率为2.31％。