1,405 research outputs found
Fig. 12. Zingiber pleiostachyum K.Schum., Chichidashan. A. Habit. B in Taxonomic revision of Zingiber (Zingiberaceae) of Taiwan
No full textFig. 12. Zingiber pleiostachyum K.Schum., Chichidashan. A. Habit. B. Leaf adaxial (left) and abaxial (right) surface. C. Ligule. D. Rhizome. E. Inflorescence. F. Flower. G. Bracts. H. Calyx tube. I. Corolla lobes. J. Labellum. K. Stamen and pistil. L. Ovary. M. Fruit. N. Seeds. Photos: A = C.T. Chao; B–N = L.P. Hsu.Published as part of Lin, Yuan-Chien, Chao, Chien-Ti, Chang, Chih-Yi & Tseng, Yen-Hsueh, 2022, Taxonomic revision of Zingiber (Zingiberaceae) of Taiwan, pp. 74-102 in European Journal of Taxonomy 839 on page 92, DOI: 10.5852/ejt.2022.839.1933, http://zenodo.org/record/711910
Thickness-Dependent Smectic- A – Smectic- C * Transition in Chiral Smectic Free-Standing Liquid-Crystal Films
No full textFig. 13. Zingiber shuanglongense C.L.Yeh & S.W.Chung, Shuanglung Logging Trail. A. Habit. B in Taxonomic revision of Zingiber (Zingiberaceae) of Taiwan
No full textFig. 13. Zingiber shuanglongense C.L.Yeh & S.W.Chung, Shuanglung Logging Trail. A. Habit. B. Leaf adaxial (left) and abaxial (right) surface. C. Ligule. D. Rhizome. E. Inflorescence. F. Flower. G. Bracts. H. Calyx tube. I. Corolla lobes. J. Labellum. K. Stamen and pistil. L. Ovary. M. Fruit. N. Seeds. Photos: L.P. Hsu.Published as part of Lin, Yuan-Chien, Chao, Chien-Ti, Chang, Chih-Yi & Tseng, Yen-Hsueh, 2022, Taxonomic revision of Zingiber (Zingiberaceae) of Taiwan, pp. 74-102 in European Journal of Taxonomy 839 on page 94, DOI: 10.5852/ejt.2022.839.1933, http://zenodo.org/record/711910
Fig. 11. Zingiber oligophyllum K.Schum., Chading Trail. A. Habit. B in Taxonomic revision of Zingiber (Zingiberaceae) of Taiwan
No full textFig. 11. Zingiber oligophyllum K.Schum., Chading Trail. A. Habit. B. Leaf adaxial (left) and abaxial (right) surface. C. Ligule. D. Rhizome. E. Inflorescence. F. Flower. G. Bracts. H. Calyx tube. I. Corolla lobes. J. Labellum. K. Stamen and pistil. L. Ovary. M. Fruit. N. Seeds. Photos: L.P. Hsu.Published as part of Lin, Yuan-Chien, Chao, Chien-Ti, Chang, Chih-Yi & Tseng, Yen-Hsueh, 2022, Taxonomic revision of Zingiber (Zingiberaceae) of Taiwan, pp. 74-102 in European Journal of Taxonomy 839 on page 88, DOI: 10.5852/ejt.2022.839.1933, http://zenodo.org/record/711910
Optical properties of oligo(9,9-diarylfluorene) derivatives in thin films and their application for organic light-emitting field-effect transistors
No full textSyntheses, Properties and Applications of homologous oligofluorenes and indenothiophene-embedded oligomers
No full text我們利用簡易的合成方法成功地合成出一系列具有不同共軛長度及側鏈之寡聚芴分子。我們於芴基C9位置引入甲苯基或是2,2’-聯苯基，可增加分子之熱穩定性，並維持芴基本身所具有之高量子產率。我們測量各寡聚芴之光物理、熱穩定、電化學和載子傳輸率，再根據各分子之物理特性，應用於藍光發光元件、紫外光發光元件、紅色磷光主體材料、液晶材料及載子量測所需之電荷產生材料，皆有非常好之元件表現。
另一方面，我們利用Negishi和Suzuki偶合反應，成功地將多電子之塞吩環引入共軛鏈中，並進一步合成出具有不同共軛系統之寡聚物。透過測量化合物之光物理、熱穩定和電化學性質，探討分子結構與性質間之關係。We have successfully synthesized homologous series of oligofluorenes with variety of C9 substituents and backbone lengths by successive Suzuki coupling reactions. The correlation between molecular structure and physical properties including thermal stability, fluorescent quantum yields, and emission wavelength etc, has been investigated systematically for probing the structure-physical property relationship. The bulky and rigid 9,9-diaryl substituents are significantly beneficial for their high morphological and thermal stability. The emission maxima of these oligomers were lying on the blue region and closely dependent on the conjugation length. Cyclic voltammetry experiments reveal that these oligofluorenes exhibit potential ambipolar carrier transport property. These intriguing characteristics render them as the most promising candidates for OLEDs. The UV-OLED and red electrophosphorecent devices have been achieved using these oligomers as emitter or host materials.
On the other hand, We have also successfully synthesized a series of thiophene-embedded conjugated oligomer with variety of backbone lengths by successive Negishi and Suzuki coupling reactions. The physical properties of these novel oligofluorene analogues are significantly altered upon introducing thiophene units as constituents. The presence of the thiophene and their coplanarity with adjacent phenylene rings provides these molecules with promising properties. We are presently fabricating light-emitting devices that incorporate these molecules as active materials.第一章 序論 1
1-1、螢光發光材料 3
1-2、藍色偏極光發光材料 14
1-3、液晶材料 16
1-4、場效電晶體材料 19
第二章、寡聚芴分子之設計、合成、性質與應用 22
2-1、寡聚芴分子之設計與合成 22
2-2、寡聚芴分子之性質分析 37
2-2.1寡聚芴的光物理性質分析 37
2-2.2寡聚芴的熱性質分析
2-2.3寡聚芴的電化學性質分析 44
52
2-2.4寡聚芴的載子傳輸性質分析 59
2-3、寡聚芴分子材料之應用 67
2-3.1藍光發光材料 67
2-3.2紫外光發光材料 68
2-3.3紅色磷光主體材料 71
2-3.4電荷產生材料 74
第三章、茚噻吩寡聚物分子之設計、合成與性質研究 78
3-1、茚噻吩寡聚物分子之設計與合成 80
3-2、茚噻吩寡聚物分子之性質研究 92
3-2.1 溶液態光物理性質 92
3-2.2熱性質 106
3-2.3電化學性質 117
3-2.4晶體結構分析 123
3-3、茚噻吩寡聚物分子研究之結論與展望 125
第四章、實驗部分 126
4-1、測試儀器 126
4-2、實驗步驟與數據 129
參考文獻 166
附錄 I、化合物TS1及IT之單晶數據 174
附錄 II、化合物之1H及13C NMR光譜圖 17
Molecular mechanism of the neurotrophic effect of GDNF on DA neurons: role of protein kinase CK2
No full textGlial cell line-derived neurotrophic factor (GDNF) is suggested as a specific neurotrophic factor for midbrain dopamine (DA) neurons, but the molecular mechanism underlying the neuroprotective action of GDNF is not well known. In the present study, we have shown that GDNF increased protein kinase CK2 activity in rat substantia nigra (SN) in a dose-dependent & time-dependent manner. This effect is prevented by prior treatment of the receptor Ret blocker K-252b. Immunostaining results also revealed that CK2 is expressed in TH-positive neurons in mesencephalon culture. Transfection of the wildtype CK2 alpha DNA increased, whereas transfection of the catalytically inactive CK2 alpha A156 mutant DNA decreased CK2 activity in the SN. CK2 alpha A156 mutant DNA also antagonized the enhancing effect of GDNF on CK2 activity. It also antagonized the enhancing effects of GDNF on tyrosine hydroxylase (TH) protein level in the SN, DA turnover in the striatum & rotarod performance in rats. Further, CK2 alpha wildtype DNA increased, whereas CK2 alpha A156 mutant DNA decreased TH activity in the SN without altering the TH protein level. On the other hand, the DA neuron toxin 1-methyl-4-phenylpyridinium iodide (MPP+) markedly decreased the number of TH-positive neurons & TH protein level in the SN, decreased DA level in the striatum & impaired rotarod performance in rats. Over-expression of the CK2alpha wildtype DNA partially, but significantly, prevented the deteriorating effect of MPP+ on these measures. Prior administration of MPP+ also antagonized the enhancing effect of GDNF on CK2 activity. These results together suggest that the CK2 signaling pathway contributes to the neuroprotective action of GDNF on DA neurons
- …
