飞机机翼微小创伤修复模具的设计

针对飞机机翼被鸟击后的快速修复提出了简便、经济、精确的精模衬垫微敲修复法,该方法的关键是衬模设计,为此分析了机翼微小创伤的修复原理,提出了三种修复方案,并对比其优缺点,最终以木质叠板为衬模材料,三坐标测量仪为数据获取工具,数控铣床及磨床为加工设备的理念完成机翼衬模的设计,并得到实际应用验证,其结果良好能够满足修复要求。     

Side-group engineering: The influence of norbornadienyl substituents on the properties of ethynylated pentacene and tetraazapentacene

The chemical modifications of 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-PEN) and 6,13-bis(triisopropylsilylethynyl)-5,7,12,14-tetraazapentacene (TIPS-TAP) by introduction of a large norbornadienyl substituent at the silyl atom of the side chain were examined and their effect on the charge transport properties in organic field-effect transistors (OFETs) was investigated. While the introduction of the norbornadienyl substituent resulted in only small changes in the crystallographic packing of these materials and did not affect the optical and electronic properties, the effect on the charge carrier mobility is significant. The hole mobility for the norbornadienyl substituted pentacene (Nor-PEN) is increased compared to similarly prepared TIPS-PEN devices, reaching up to 0.75 cm²/Vs. On the other hand, the electron mobility of the tetraaza derivative (Nor-TAP) is reduced by an order of magnitude compared to its parent TIPS-TAP. The strong effect of the norbornadienyl substitution on the charge carrier mobilities can be explained by the calculation of the transfer integrals and the microstructure of the resulting films of the Nor-derivatives.     

Improved morphology and enhanced stability via solvent engineering for planar heterojunction perovskite solar cells

Solvent engineering technique for planar heterojunction perovskite solar cells is an efficient way to achieve uniformly controlled grain morphology for perovskite films. In this report, diethyl ether solvent engineering technique was used for Methyl ammonium lead triiodide (CH₃NH₃PbI₃) perovskite thin films for planar heterojunction solar cells which exhibited a PCE of 9.20%. Morphological improvements and enhanced grain sizes leads to enhanced absorption of CH₃NH₃PbI₃. Moreover solar cells have showed an excellent environmental stability of more than 100 days. This increase in efficiency is due to improved film morphology of perovskite layer after solvent treatment which has been revealed under UV–Vis spectroscopy, SEM images, X-ray diffraction and impedance spectroscopy.     

One barbiturate and two solvated thiobarbiturates containing the triply hydrogen‐bonded ADA/DAD synthon,plus one ansolvate and three solvates of their coformer 2,4‐diaminopyrimidine

A path to new synthons for application in crystal engineering is the replacement of a strong hydrogen‐bond acceptor, like a C=O group, with a weaker acceptor, like a C=S group, in doubly or triply hydrogen‐bonded synthons. For instance, if the C=O group at the 2‐position of barbituric acid is changed into a C=S group, 2‐thiobarbituric acid is obtained. Each of the compounds comprises two ADA hydrogen‐bonding sites (D = donor and A = acceptor). We report the results of cocrystallization experiments of barbituric acid and 2‐thiobarbituric acid, respectively, with 2,4‐diaminopyrimidine, which contains a complementary DAD hydrogen‐bonding site and is therefore capable of forming an ADA/DAD synthon with barbituric acid and 2‐thiobarbituric acid. In addition, pure 2,4‐diaminopyrimidine was crystallized in order to study its preferred hydrogen‐bonding motifs. The experiments yielded one ansolvate of 2,4‐diaminopyrimidine (pyrimidine‐2,4‐diamine, DAPY), C₄H₆N₄, (I), three solvates of DAPY, namely 2,4‐diaminopyrimidine–1,4‐dioxane (2/1), 2C₄H₆N₄·C₄H₈O₂, (II), 2,4‐diaminopyrimidine–N,N‐dimethylacetamide (1/1), C₄H₆N₄·C₄H₉NO, (III), and 2,4‐diaminopyrimidine–1‐methylpyrrolidin‐2‐one (1/1), C₄H₆N₄·C₅H₉NO, (IV), one salt of barbituric acid, viz. 2,4‐diaminopyrimidinium barbiturate (barbiturate is 2,4,6‐trioxopyrimidin‐5‐ide), C₄H₇N₄⁺·C₄H₃N₂O₃⁻, (V), and two solvated salts of 2‐thiobarbituric acid, viz. 2,4‐diaminopyrimidinium 2‐thiobarbiturate–N,N‐dimethylformamide (1/2) (2‐thiobarbiturate is 4,6‐dioxo‐2‐sulfanylidenepyrimidin‐5‐ide), C₄H₇N₄⁺·C₄H₃N₂O₂S⁻·2C₃H₇NO, (VI), and 2,4‐diaminopyrimidinium 2‐thiobarbiturate–N,N‐dimethylacetamide (1/2), C₄H₇N₄⁺·C₄H₃N₂O₂S⁻·2C₄H₉NO, (VII). The ADA/DAD synthon was succesfully formed in the salt of barbituric acid, i.e. (V), as well as in the salts of 2‐thiobarbituric acid, i.e. (VI) and (VII). In the crystal structures of 2,4‐diaminopyrimidine, i.e. (I)–(IV), R₂²(8) N—H…N hydrogen‐bond motifs are preferred and, in two structures, additional R₃²(8) patterns were observed.     

Charge selectivity in polymer:Fullerene-based organic solar cells with a chemically linked polyethylenimine interlayer

The power conversion efficiency of solar cells can be optimized via an efficient charge collection by electrodes. In this study, a simple linear polyethylenimine (LPEI), which is an insulating polymer, was adopted as the cathode interfacial layer of poly(3-hexylthiophene) (P3HT):[6,6]-phenyl-C₆₁-butyric acid methyl ester (PCBM)-based bulk-heterojunction organic solar cells (OSCs) with a non-inverted configuration. All photovoltaic parameters of the OSCs were significantly enhanced by depositing LPEI onto the oxygen plasma-treated P3HT:PCBM active layers. The causes of performance enhancement in OSCs were studied. Results revealed that the microstructure and morphology of the P3HT:PCBM layer were almost unaffected by the oxygen plasma treatment and the subsequent LPEI deposition. The X-ray photoelectron spectra of the specimens demonstrated that with the aid of oxygen plasma treatment, the linked LPEI molecules formed a well-aligned dipole layer on top of the P3HT:PCBM layer through the bonding of nitrogen (N) with oxygen (O). The results from quantum chemical calculations showed that the LPEI molecule with an N–O bond had a larger dipole moment at an appropriate direction than that without an N–O bond. By contrast, the LPEI molecules can form a dipole layer with a random orientation in the absence of N–O bonds. The conductive atomic force microscopy images of the specimens showed that the well-aligned dipole layer could facilitate electron transfer and could block hole transfer from the P3HT:PCBM to the cathodes. The well-aligned and augmented interface dipoles improved the charge selectivity at the cathodes and the photovoltaic performance of the devices.     

基于信息管理系统在水利工程建设管理中的应用探讨

本文提出采用信息管理系统加强对水利工程建设进行管理,阐述了信息系统应用于水利工程建设中的必要性,并针对水利工程管理信息系统中存在的问题进行论述,归纳和总结出几点改善措施,希望能够为全面提升水利工程管理工作效率提供保障.