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941.
942.
本文综述了用于193 nm深紫外光刻胶的主体成膜树脂的种类及常用合成单体的研究进展,包括聚(甲基)丙烯酸酯体系、环烯烃-马来酸酐共聚物(COMA)体系、乙烯醚-马来酸酐共聚物(VEMA)体系、降冰片烯加成聚合物体系、环化聚合物体系、有机-无机杂化树脂体系以及光致产酸剂(PAG)接枝聚合物主链型等,并分析了目前关于曝光、分辨率和抗蚀刻性能方面存在的问题及未来的发展方向。 相似文献
943.
944.
本文用交流阻抗法研究了Bi_2O_3-Y_2O_3系的阻抗谱。呈现特有的Warburg阻抗及其相关阻抗。在高氧分压下,电极过程由氧原子在三相线发生反应后直接进入电解质步骤控制;低氧分压下,由上述步骤和界面浓差极化共同控制,或仅由浓差极化控制。在氧分压为1.01×10~(-10)~1.01×10~5Pa内时,Bi_2O_3-Y_2O_3系表现为纯氧离子导体。 相似文献
945.
Tubiferal A, a novel rearranged triterpenoid lactone, has been isolated from field-collected fruit bodies of the myxomycete, Tubifera dimorphotheca, and its structure elucidated by spectral data. Tubiferal A (1) possesses a 9,10-secocycloartan-16,21-olide skeleton, and this new compound exhibited a reversal effect of vincristine (VCR) resistance (more than 4-fold) against VCR-resistant KB cell lines. Tubiferal B (2), corresponding to the seco acid of 1 was also isolated, but showed no comparable activity. 相似文献
946.
Nam-Suk Lee Hoon-Kyu Shin Young-Soo Kwon 《Colloids and surfaces. A, Physicochemical and engineering aspects》2006,290(1-3):77-81
Recently, research on conducting molecules containing thiol functional groups such as benzenethiol has been progressing [X. Xiao, B. Xu, N.J. Tao, Nano Lett. 4 (2004) 267]. This conducting molecule is applicable to the study of the negative differential resistance (NDR) and switching properties of logic device. The 4-{4[4-(4-{1-[4-(4-acetylsulfanyl-phenylethynyl)-phenyl]-2,6-diphenyl-pyridinium-4-yl}-phenyl)-2,6-diphenyl-pyridinium-1-yl]-phenylethynyl}-phenylthioacetate (dipyridinium) molecule contains thiol functional groups such as benzenethiol. Thus, we have studied an NDR property of a dipyridinium molecule using the self-assembly method in scanning tunneling microscopy (STM). The Au substrate was exposed to a 1 mM solution of 1-dodecanethiol in ethanol for 24 h to form a monolayer. After thorough rinsing of the sample, it was exposed to a 0.1 μM solution of dipyridinium in dimethylformamide (DMF) for 30 min. After the assembly, we measured the electrical properties of the self-assembly monolayers (SAMs) using ultra high vacuum scanning tunneling microscopy (UHV-STM) and scanning tunneling spectroscopy (STS). As a result, we confirmed the properties of NDR in a negative region at −1.67 V and a positive region at 1.78 V. The energy gap (Eg) was found to be 3.12 eV [C. Arena, B. Kleinsorge, J. Robertson, W.I. Milne, M.E. Welland, J. Appl. Phys. 85 (1999) 1609]. This molecule is applicable to the fabrication of molecular junctions. 相似文献
947.
948.
The degree of compatibilization between natural rubber (NR) and acrylonitrile‐butadiene rubber (NBR) was investigated by two different methods. NBR was chemically modified with maleic anhydride in a screw twin mixer with and without reaction initiator, benzoyl peroxide. Also, the effects of molecular weight of liquid natural rubber (LNR) as a compatibilizer were studied. The degree of compatibilization between NBR and NR is determined indirectly through measurements of mechanical properties and impact resistance. The maleic anhydride and benzoyl peroxide concentrations influence the mechanical properties and impact resistance of the blends. Also, the mechanical properties of the blends showed that the molecular weight of LNR played an important role in determing their performance. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
949.
Late embryogenesis abundant (LEA) proteins are mainly low molecular weight (10–30 kDa) proteins, which are involved in protecting higher plants from damage caused by environmental stresses, especially drought (dehydration). These findings and the fact that the breeding of drought tolerant varieties would be of great value in agriculture, form the basis of search for anti-drought inducible genes and their characterization. LEA proteins are generally classified into six groups (families) according to their amino acid sequence and corresponding mRNA homology, which are basically localized in cytoplasm and nuclear region. LEA protein synthesis, expression and biological activities are regulated by many factors (e.g. developmental stages, hormones, ion change and dehydration), signal transduction pathways and lea genes. No tissue-specific lea gene expression has been considered as one main regulatory mechanism on the basis of extensive studies with the model plant, Arabidopsis thaliana. The study of the regulatory mechanism of lea gene expression is an important feature of modern plant molecular biology. 相似文献
950.
Efficient and reversible fluorescence modulation with excellent photo-stability was achieved from a sulfone form of diacetyl diarylethene, 1,2-bis(6-acetyl-2-methyl-1-benzothiophene-1,1-dioxide-3-yl)perfluorocyclopentene (DABTFO4). The DABTFO4 emits strong fluorescence in the closed-ring isomer even in the absence of extra fluorophores. The fluorescence quantum yield, fatigue resistance, and photo-cyclization yield of DABTFO4 were significantly improved compared with the unsubstituted 1,2-bis(2-methyl-1-benzothiophene-1,1-dioxide-3-yl)perfluorocyclopentene (BTFO4) and the sulfide analogue, 1,2-bis(6-acetyl-2-methyl-1-benzothiophene-3-yl)perfluorocyclopentene (DABTF6). 相似文献