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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
161

Construction of Low‐Symmetric and Light-­Switchable Coordination Cages for Guest Uptake and Catalysis

Han, Muxin 08 October 2015 (has links)
No description available.
162

Srovnání misantropní talk Show Jana Krause a filantropní talk show Marka Ebena Na plovárně / Comparing misanhropist talk show Jana Krause and philantrhropist talk show Marek Eben's Na plovárně

Kopřivová, Jitka January 2015 (has links)
The theoretical section of the thesis Comparison of the misanthropic Show Jana Krause and the philanthropic Mark Eben's show Na plovárně aims to characterize the talk show genre both abroad and in the Czech Republic. It briefly outlines the development of the genre and its arrival in the Czech television stations. It also gives a definition of a presenter, describes the ways of communication, construction of the interviews with the guests, their selection, introduces Jan Kraus and Marek Eben and characterises both talk shows - Na Plovárně and Show Jana Krause. The practical section deals with an analysis of production in which interviews with representatives of both production teams are analysed. A qualitative analysis aims to answer the question: "How do the philanthropic and misanthropic concepts of the talk show differ, from the perspective of content and production intentions?" The conclusion contains a summary of the collected data.
163

Studium teplotně citlivých porfyrinů a jejich supramolekulárních komplexů / Studium teplotně citlivých porfyrinů a jejich supramolekulárních komplexů

Hrubovský, Martin January 2016 (has links)
Study of thermoresponsive porphyrins and their supramolecular complexes Abstract: We studied the water-soluble artificial compound meso-tetrakis{3,4,5-tris[2-(2-(2- methoxyethoxy)ethoxy)ethoxy]phenyl}porphyrin prepared at NIMS, Japan, using the high-resolution NMR spectroscopy experimental method. We observed its LCST-type phase separation and applied the Flory-Huggins theory of polymer solutions in order to find its phase diagram (binodal and spinodal curves of the phase separation) and we also obtained molar enthalpies, entropies and critical temperatures of its phase separation; from the Flory-Huggins theory we discovered that its molecules form dimers in aqueous solutions. We also studied its host-guest interactions with the S-camphorsulfonic acid; we learned that the porphyrin binds cations and the porphyrin dimers break down when dissolved cations are available for complexation. We observed no phase separation in chloroform. We obtained no proof of the existence of molecular stacks larger than dimers. 1
164

Efeitos de confinamento em líquidos iônicos hidratados

Zanatta, Marciléia January 2017 (has links)
Líquidos iônicos imidazólios (LIIs) associados a ânions com caráter básico foram sintetizados, caracterizados e seu comportamento estudado em solução. Inicialmente a troca isotópica H/D preferencial no grupo C2-CH3 de sais de 1-nbutil-2,3-dimetilimidazólio (BMMI) foi avaliada. Ficou evidente que o contato entre os pares de íons e a atuação do ânion como uma base neutra influenciaram fortemente a deuteração. Após a análise dos resultados de RMN, cálculos de DFT (Teoria do Funcional de Densidade) e Difração de Raios X, um complexo entre uma molécula de água e alguns LI foi sugerido, modificando fortemente a estrutura organizacional e afetando também a troca isotópica nestes sais. Através do mecanismo reacional proposto, surgiu a possibilidade de deuteração de novos substratos contendo H ácidos, usando os LIIs como catalisadores. A reação de troca isotópica em alcinos e cetonas foi estudada e bons resultados foram obtidos. O efeito da variação de cátions e ânions na atividade catalítica foi analisado, assim como a variação dos substituintes dos substratos. Além disso, um estudo cinético foi realizado através de análises de RMN de 1H e o mecanismo reacional foi proposto. Por fim, a capacidade de formação de pares iônicos em soluções aquosas de LIIs foi avaliada na captura de CO2. Ótimos resultados foram obtidos e atribuídos à ocorrência de sorção física e química devido à ativação da água pelo LII. / Imidazolium based ionic liquids (ImIL) associated with basic anions were synthesized, characterized and studied. Initially the preferred H/D isotopic exchange to C2-CH3 group of 1-nbutyl-2,3-dimethylimidazolium salts (BMMI) was studied. In this context, it became evident that the ion-pairing formation and the anion action as a neutral base strongly influence the deuteration reaction. NMR analysis, theoretical calculation (Density Functional Theory) and X-ray Diffraction have been performed and a complex between a water molecule and the IL have been suggested, strongly modifying the IL structure and characteristics. The isotope exchange reaction in alkynes and ketones was studied using imidazolium based ionic liquids as catalysts and good results obtained. The effect of cation and anion variation on the catalyst activity were analyzed, also a variation of the substrate substituent’s. Also, a kinetic study was performed by 1H NMR analyzes and the reaction mechanism were proposed. Finally, the ability to form ion pair contact of ILs in aqueous solutions was evaluated for CO2 capture. Great results were obtained and this success can be attributed to the occurrence of physical and chemical sorption due to water activation by the IL.
165

Chloromethane Complexation by Cryptophanes : Host-Guest Chemistry Investigated by NMR and Quantum Chemical Calculations

Takacs, Zoltan January 2012 (has links)
Host–guest complexes are widely investigated because of their importance in many industrial applications. The investigation of their physico–chemical properties helps understanding the inclusion phenomenon. The hosts investigated in this work are cryptophane molecules possessing a hydrophobic cavity. They can encapsulate small organic guests such as halo–methanes (CH2Cl2, CHCl3). The encapsulation process was investigated from both the guest and the host point of view. With the help of Nuclear Magnetic Resonance (NMR), the kinetics of complex formation was determined. The information was further used to obtain the activation energies of the processes. Having done this on five different cryptophanes, it is possible to relate the energies to structural differences between the hosts. Via the dipolar interaction between the guest’s and host’s protons, one can get information on the orientation of the guest inside the cavity. Moreover, the dynamics of the guest can be further investigated by its relaxation properties. This revealed restricted motion of the guest inside the host cavity. Not only the nature of the guest plays an important role. The host is also changing its properties upon encapsulation. All the cryptophanes investigated here can exchange rapidly between many conformers. These conformers have different–sized cavities. Quantum chemical optimization of the structure of the conformers makes volume estimation possible. Not only the cavity volumes, but also the quantum-chemically obtained energies and the calculated chemical shifts of the carbon–13 atoms can be helpful to follow the changes of the host upon complex formation. The host cannot be considered as a rigid entity. Analysis of variable temperature proton and carbon-13 spectra shows that the encapsulation can be considered as a mixture of conformational selection and induced fit. The structures of the formed complexes are further investigated by means of two-dimensional nuclear Overhauser spectroscopy (NOESY). The complex formation, its kinetics and thermodynamics are found to be a complicated function of structure elements of the host, the cavity size and the guest size and properties. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Accepted. Paper 5: Manuscript.</p><p> </p>
166

Biocatalytic Production, Preparation and Characterization of Large-ring Cyclodextrins

Mokhtar, Mohd Noriznan 04 March 2009 (has links) (PDF)
Cyclodextrins (CD) are cyclic oligosaccharides composed of six to more than sixty glucose units. Large-ring cyclodextrins (LR-CD) are novel CD comprised of more than eight glucose units with cavity structures and sizes different from that of commercially available CD<sub>6</sub> – CD<sub>8</sub>. LR-CD may offer unique molecular recognition properties and can be produced biocatalytically from starch using cyclodextrin glucanotransferase (CGTase, E.C. 2.4.1.19) in a short reaction time. LR-CD were isolated from glucose, CD<sub>6</sub> – CD<sub>8</sub> and other compounds by complexation of CD<sub>6</sub> – CD<sub>8</sub> as well as precipitation techniques. The yield of LR-CD (degree of polymerization from 9 to 21) was optimized using central composite design. Addition of polar organic solvents to the synthesis resulted in higher yields of LR-CD. LR-CD composed of 9 to 21 glucose units were successfully separated using reversed-phase of ODS-AQ chromatography and normal-phase of polyamine II chromatography. Maintaining optimized reaction conditions aided in a high yield of CD<sub>9</sub>; it could be separated with reasonable yield using a single step of polyamine II chromatography. A co-grinding method helped to obtain higher solubilization levels of glibenclamide, vitamin A acetate and vitamin D<sub>3</sub> in CD<sub>13</sub>, CD<sub>10</sub> and CD<sub>11</sub>, respectively when compared to other CD. Vitamin K<sub>1</sub> was solubilized in distilled water with CD<sub>6</sub> – CD<sub>13</sub> using a co-precipitation method. When compared with other CD, CD<sub>9</sub> was seen to be the best solubilizer. The analysis of complexes using ESI MS showed spironolactone and glibenclamide complexed with CD<sub>9</sub> and CD<sub>13</sub>, respectively.
167

Structure and spectroscopy of bio- and nano-materials from first-principles simulations

Hua, Weijie January 2011 (has links)
This thesis is devoted to first-principles simulations of bio- and nano-materials,focusing on various soft x-ray spectra, ground-state energies and structures of isolated largemolecules, bulk materials, and small molecules in ambient solutions. K-edge near-edge x-ray absorption fine structure (NEXAFS) spectra, x-ray emission spectra, andresonant inelastic x-ray scattering spectra of DNA duplexes have been studied by means oftheoretical calculations at the density functional theory level. By comparing a sequence of DNAduplexes with increasing length, we have found that the stacking effect of base pairs has verysmall influence on all kinds of spectra, and suggested that the spectra of a general DNA can bewell reproduced by linear combinations of composed base pairs weighted by their ratio. The NEXAFS spectra study has been extended to other realistic systems. We have used cluster modelswith increasing sizes to represent the infinite crystals of nucleobases and nucleosides, infinitegraphene sheet, as well as a short peptide in water solution. And the equivalent core holeapproximation has been extensively adopted, which provides an efficient access to these largesystems. We have investigated the influence of external perturbations on the nitrogen NEXAFSspectra of guanine, cytosine, and guanosine crystals, and clarified early discrepancies betweenexperimental and calculated spectra. The effects of size, stacking, edge, and defects to theabsorption spectra of graphene have been systematically analyzed, and the debate on theinterpretation of the new feature has been resolved. We have illustrated the influence of watersolvent to a blocked alanine molecule by using the snapshots generated from molecular dynamics. Multi-scale computational study on four short peptides in a self-assembled cage is presented. It isshown that the conformation of a peptide within the cage does not corresponds to its lowest-energyconformation in vacuum, due to the Zn-O bond formed between the peptide and the cage, and theconfinement effect of the cage. Special emphasis has been paid on a linear-scaling method, the generalized energy basedfragmentation energy (GEBF) approach. We have derived the GEBF energy equation at the Hartree-Focklevel with the Born approximation of the electrostatic potential. Numerical calculations for amodel system have explained the accuracy of the GEBF equation and provides a starting point forfurther refinements. We have also presented an automatic and efficient implementation of the GEBFapproach which is applicable for general large molecules. / QC 20110404
168

Die Strukturabhängigkeit der Festkörperfluoreszenz bei Phosphanylanthracenen / The relationship of solid-state fluorescence and molecular structure in phosphanylanthracenes

Schwab, Gerald Harald 30 April 2008 (has links)
No description available.
169

台灣與印尼雙邊跨境移工政策:以在台逃逸印尼勞工為例 / Coordinating Migrant Labor Policy between Taipei and Jakarta: The Case of Runaway Indonesian Workers

范安曼, Faustina, Anselma Unknown Date (has links)
由於印尼為世界上人口最多的國家之一,因此憑藉著此一優勢印尼成為了勞工輸出大國,但是非常多的印尼勞工在外國工作時面臨虐待,因而產生了不少問題,另一方面,台灣是印尼勞工們選擇工作的優先地,主要原因有三個,第一為較高的薪水,第二為較好的生活品質及良好的工作環境,第三不公平對待相較於他國較少發生,儘管如此台灣政府仍面臨著管理外籍勞工的問題,特別是逃逸的外籍勞工的問題,而在台灣的逃逸外勞比例中,印尼勞工占了最高比例。 先前的研究主要在於分析台灣的逃逸外勞現象,並且把此一現象歸因於台灣的移工政策所造成,但是現有的研究主要是針對菲律賓的勞工而不是印尼勞工,因此對於印尼逃逸勞工現象研究則相較較少。 考慮到外籍勞工議題涵蓋的層面多元,如多方的參與者,因此本篇論文將專注於闡述與探討負責輸出勞工及輸入勞工國家的角色及政策。本篇論文主要分為兩部份,第一部分,由於台灣的移工政策對於外國勞工非常嚴格,因此台灣的移工政策造成了印尼勞工過多的負擔,第二台灣和印尼政府無效率的配合,兩國政府只專注於表面並無徹底了解並從其根本解決勞工問題,這兩項因素造成了高比率的逃逸印尼勞工問題,除此之外,本篇論文亦將包含清楚的台灣政府和印尼政府的勞工政策發展,為了更清楚了解此一議題,本篇論文也向移民署收容所作問卷調查,訪問避難所的逃逸勞工,和研究台印勞工現象的專家學者們進行團體討論,本篇分析結果來自問卷調查及訪問,並將此一結果與現有的印尼及台灣政府的政策與合作進行分析。 / As one of the most populous country in the world, Indonesia’s predominance is sending its human resources to work abroad. However, many Indonesian overseas workers encounter mistreatment during their work time which leads to several arising problems. On the other hand, Taiwan has become one of the preferred destination countries due to three reasons; higher salary, better living and working conditions, and low mistreatment cases compare to other destination countries. Despite that, Taiwan government still encounters issues in managing foreign workers. Runaway foreign worker is a major issue in Taiwan’s labor market and Indonesian workers are accounted as the highest runaway foreign workers in Taiwan. Previous researches have been conducted to analyze the phenomenon of runaway foreign workers in Taiwan and most of them addressed Taiwanese guest worker policy as the major reason. Research on runaway Indonesian workers in particular is very limited as most of the existing researches focused on Filipinas workers. Taking into account that foreign workers issue is a multi-faceted phenomenon which involves various actors, this thesis acknowledges the roles and policies from both sending and host states. Therefore this thesis delivers two arguments. First, Taiwan’s guest worker policy has put excessive burden on Indonesian workers as Taiwan employs highly restrictive policy towards foreign workers. Second, Indonesia and Taiwan’s ineffective cooperation is unable to address the existing runaway Indonesian workers issue as it emphasizes more on scratching the surface than dealing with the root causes. These two variables have inadvertently contributed to the high number of runaway Indonesian workers. In addition, this thesis also delivers a clear labor policy development in Indonesian and Taiwan government to understand each institution’s in-take related to labor issues. In order to provide comprehensive findings, this thesis conducts survey with the Indonesian runaway workers in Detention Center, interview with the runaway Indonesian workers in shelters, and focus group studies with Indonesian and Taiwanese experts who are dealing with such phenomenon. The analysis is drawn from the results of survey and interview, and then is connected to the current Indonesian and Taiwanese policies and cooperation in addressing particular issue.
170

Porphyrin-based [3]- and [4]rotaxanes : towards an adaptable molecular receptor

Roche, Cécile 20 April 2012 (has links) (PDF)
Rotaxanes and porphyrins are two particularly active fields of research in chemistry. However,molecules that combine the interesting properties of these types of structures are not so common. In this thesis we describe new porphyrin-based multi-rotaxanes, whose syntheses constitute interesting challenges.Porphyrins linked to two or four coordinating macrocycles were synthesised. The "gathering-andthreading" effect of copper(I) was used to thread molecular rods through the rings; the subsequent introduction of stoppers led to the formation of rotaxanes. In the case of the porphyrinic bis-macrocycle a [4]rotaxane was obtained. Host/guest complexation studies with rigid nitrogen ligands showed that the rotaxane behaves as a distensible molecular receptor that can adopt an "inflated" or "deflated" conformation and adjust its shape to the size of the guest. In the case of the porphyrinic tetra-macrocycle the formation of a [3]rotaxane of novel architecture was observed.The synthesis of a new, more rigid bis-macrocycle is in progress. This compound will be used for the construction of a [4]rotaxane that could act as a molecular press able to change the conformation of a guest substrate by compression.

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