8,726 research outputs found
Chinese symphonic concert
No full textconducted by Hsueh-yen Yao.Radio broadcast (Pending for review)"如蘭教授指正 姚學言敬贈 AUG.11/85"--Index."84.7.21"--Side A label.Electronic reproduction from Rulan Chao Pian Audio Cassette Collection.Performers: Berkeley Symphony Orchestra.Program spoken in English."Rulan jiao shou zhi zheng Yao Xueyan jing zeng AUG.11/85"--Index
Clinical Trials of Eclipta Prostrata (L.)L as Hepatoprotective and Their Market Formulations"
No full textNot availabl
Highly Selective Na+-Templated Formation of [2]Pseudorotaxanes Exhibiting Significant Optical Outputs
No full textHighly Selective Na+-Templated Formation of [2]Pseudorotaxanes Exhibiting Significant Optical Outputs
No full text金屬離子與分子籠鍵結所產生的模板效應可順利引導兩種不同的兩個客體分子(蒽醌及方酸衍生物)進入分子籠的中心空腔而形成準車輪烷類錯合物，有趣的是在Li+、Na+、K+、Cs+等鹼金屬中，僅有鈉離子具有如此的模板效應。由於此超分子系統在進行錯合與解離的過程中可產生明顯的顏色或螢光變化，因此或有成為具光學輸出之分子開關的潛力。A molecular cage forms pseudorotaxane-like complexes with threaded anthraquinone and squaraine units in the presence of templating alkali metal ions, with high selectively for Na+ ions. This ion-specific templating effect was easy to monitor because the complexation and decomplexation of the pseudorotaxane complexes in solution occurred with significant color changes that were detectable to the naked eye.摘 要 I
Abstract Ⅱ
論文發表 Ⅲ
目 錄 IV
式 子 V
圖 表 VI
表 格 VIII
壹、導 論 1
1.1 前言 1
1.2 超分子化學的發展與冠醚的起源 3
1.3 超分子系統 6
1.3.1 氫鍵 6
1.3.2 金屬－配位基 8
1.3.3 pi-pi疊合
1.3.4 疏水作用力 12
貳、結果與討論 14
2.1 研究動機 14
2.2 分子籠2的設計與合成及預期功能 17
2.3 分子籠2與蒽醌3之錯合體 18
2.4 分子籠2與蒽醌4之錯合體 23
2.5 分子籠2與鈉、鉀離子鍵結的探討 28
參、結 論 30
肆、實驗部份 31
伍、參考文獻 3
Semi-blind adaptive beamforming for high-throughput quadrature amplitude modulation systems
No full textA semi-blind adaptive beamforming scheme is proposed for wireless systems that employ high-throughput quadrature amplitude modulation signalling. A minimum number of training symbols, equal to the number of receiver antenna arrays elements, are first utilised to provide a rough initial least squares estimate of the beamformer's weight vector. A concurrent constant modulus algorithm and soft decision-directed scheme is then applied to adapt the beamformer. This semi-blind adaptive beamforming scheme is capable of converging fast to the minimum mean-square-error beamforming solution, as demonstrated in our simulation study
Disulfide-linked head-to-head multimerization in the mechanism of ion channel clustering by PSD-95
No full textThe PSD-95/SAP90 family of PDZ-containing proteins is directly involved in the clustering of specific ion channels at synapses. We report that channel clustering depends on a conserved N-terminal domain of PSD-95 that mediates multimerization and disulfide linkage of PSD-95 protomers. This N-terminal multimerization domain confers channel clustering activity on a single PDZ domain. Thus, channel clustering depends on aggregation of PDZ domains achieved by head-to-head multimerization of PSD-95, rather than by concatenation of PDZ domains in PSD-95 monomers. This mechanism predicts that PSD-95 can organize heterogeneous membrane protein clusters via differential binding specificities of its three PDZ domains. PSD-95 and its relative chapsyn-110 exist as disulfide-linked complexes in rat brain, consistent with head-to-head multimerization of these proteins in vivo
The Syntheses and Applications of Squaraine-Based Molecular Switches
No full text本篇論文分為四個部份，分別為利用滑套法合成方酸染料之[2]車輪烷分子、以方酸染料為架構之分子開關的合成及應用、利用固體研磨方式有效率地合成[2]-及[4]車輪烷分子，以及合成具有膠體性質之酸/鹼及陰離子雙向控制分子開關。
第一部份：利用滑套法合成方酸染料之[2]車輪烷分子
我們利用滑套法有效地合成以分子籠包覆方酸染料之[2]車輪烷分子。由於方酸染料本身具有長波長的吸收及螢光放射，有機會被應用在生醫顯影等方向，但卻容易受到外來的親核試劑攻擊而降低其應用價值。利用鈉離子作為模板，使方酸染料進入籠狀分子的空腔而形成車輪烷分子，不但可以增加方酸染料分子在親核試劑下存活的時間，並且可增加其螢光強度。
第二部份：以方酸染料為架構之分子開關的合成及應用
我們以鈉離子為模板，使方酸衍生物與大環分子鍵結形成準[2]車輪烷分子，再以穿透後末端封鎖法合成出具有兩個辨識中心的[2]車輪烷分子，透過加入或移除鈉離子可控制分子籠於方酸染料及吡啶陽離子間進行位置異構化(translational isomerization)，進而造成方酸衍生物在螢光強度上的差異，以形成一肉眼可辨識之光學分子開關。
第三部份：利用固態合成方式有效率地合成[2]-及[4]車輪烷分子
封鎖基(1,8-diaminonaphthalene)與末端具有醛類官能基之準車輪烷，可在固態研磨的條件下有效地形成[2]車輪烷分子。複雜的車輪烷分子如[4]車輪烷，亦可透過預先混合後抽乾再與封鎖基進行研磨而得到。
第四部份：合成具有膠體性質之酸/鹼及陰離子雙向控制分子開關
我們設計並合成一個具有二級銨鹽和尿素等官能基之車輪烷分子，此車輪烷分子不但是一個酸/鹼及陰離子之分子開關，並可在特定溶劑中形成膠狀物質。透過酸-鹼及陰離子的加入及移除不僅可以操縱此分子開關的動作，更可以控制此膠狀物質的膠態與溶液態轉換(sol-gel transformation)，透過TEM與AFM實驗觀察，我們發現膠狀物質是由許多纖維狀物質糾結在一起並包覆溶劑分子而形成。This thesis consists of four parts. The first part is protecting a squaraine near-IR dye through its incorporation in a slippage-derived [2]rotaxane; the second part is to design and synthesize squaraine-based [2]rotaxanes that function as visibly active molecular switches; the third part is to develop efficient solvent-free syntheses of [2] and [4]rotaxanes; the last part is reporting the serendipitous discovery of an acid/base- and anion-controllable organogel formed from urea-based molecular switch.
Part Ⅰ：Protecting a Squaraine near-IR Dye through Its Incorporation in a Slippage-Derived [2]Rotaxane
We report high yield slippage synthesis of corresponding [2]rotaxanes according to previous works that unique Na+ ion-templated recognition system. The photophysical properties and chemical stability of a squaraine dye were enhanced by encirclement of a molecular cage.
Part Ⅱ：Squaraine-Based [2]Rotaxane that Function as Visibly Active Molecular Switches
We used Na+ ions to template a threading-followed-by-stoppering synthesis of a [2]rotaxane from the squaraine-containing pyridinium derivative and a molecular cage. This [2]rotaxane would function as a molecular switch in CD3CN if we could remove the templating Na+ ions and thereby move the molecular cage from the squaraine station to the pyridinium or bipyridinium one, this process should have the effect of decreasing the intensity of the [2]rotaxane’s long-wavelength-fluorescence emission.
Part Ⅲ：Efficient Solvent-Free Syntheses of [2]- and [4]Rotaxanes
We chose 1,8-diaminonaphthalene as a suitable diamine for the reaction with a threadlike moiety terminated with a formyl group through a new solid-state ball-milling reaction that produces both [2]- and [4]rotaxanes efficiently and in high yield.
Part Ⅳ：An Acid/Base- and Anion-Controllable Organogel Formed From Urea-Based Molecular Switches
We report the serendipitous discovery of a urea-based rotaxane that behaves as both a molecular switch and an organogelator, with both functions being mediated under acid/base and anion control
Protecting a Squaraine near-IR Dye through Its Incorporation in a Slippage-Derived [2]Rotaxane
No full text- …
