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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.
1

Sobre as interações eletrônicas em algumas ciclanonas e em 2-ciclopentenona, substituídas em α por um átomo de enxofre / About electronic interactions and in some ciclanonas 2-cyclopentenone, α substituted by a sulfur atom

Calegao, Isabel Cristina Coelho 23 January 1981 (has links)
Este trabalho investiga as interações eletrônicas em algumas cetonas cíclicas, substituídas em α por um átomo de enxofre, pela comparação com os compostos substituídos correspondentes. Os compostos estudados eram: ciclopentanona (I), 2-mercaptociclopentanona (II), 2-metiltiociclopentanona (III), 2-etiltiociclopentanona (IV), 2-n-propilciclopentanona (V), cânfora (VI), 2-etilcânfora (VII), 2-metiltiocânfora (VIII), ciclohexanona (IX), 2 -metilciclohexanona (X), 2-etiltiociclohexanona (XI), 2-hexanona (XII), etiltioacetona (XIII), 3-tiaciclopentanona (XIV), 3-tiaciclohexanona (XV), 2-ciclopentenona (XVI), 2-etiltio-2-ciclopentenona (XVII), l-etiltiociclopenteno (XVIII), ciclopenteno (XIX), ciclopentanotiol (XX) e etiltiociclopentano (XXI) (ver arquivo). São apresentadas as revisões bibliográficas sobre interações eletrônicas em compostos carbonílicos β-tia-substituídos e em vinil- e aril-tioéteres. São descritas as sínteses de compostos (II)-(V), (VII), (XVI)-(XVIII), (XX) e (XXI) por nós efetuadas. São apresentadas as constantes de basicidade de cetonas (I)-(XVII) e as medidas no ultravioleta de compostos (I-III), (XVI)-(XXI). Os dados experimentais indicam que: 1 - Todos os compostos carbonílicos contendo enxofre apresentam basicidade menor em relação aos compostos correspondentes não sulfurados. Entretanto, a grandeza desta diminuição não é a mesma para todos os compostos estudados. 2 - As bandas η → π* e π → π* do espectro no ultravio1eta de 2-etiltio-2-ciclopentenona (XVII) sofrem deslocamentos batocrômicos em comparação com as ciclanonas saturadas e ciclopentenos, respectivamente. Entretanto, a banda ηs → σ* é semelhante a de tioéteres e tióis. É apresentada uma discussão dos resultados obtidos, na qual sugere-se que: A diminuição da basicidade depende da posição da ligação C-S em relação ao grupo carbonila, sendo maior quando o ângulo de projeção Φ se aproxima de 0 ou 180°. A diminuição de basicidade é devida a interação no espaço e/ou através das ligações entre os pares de elétrons do enxofre e oxigênio carbonílico. A pequena diminuição de basicidade observada em 2-eti1tio-2-ciclopentenona de conformação plana é proveniente do cancelamento parcial do efeito da interação pelo efeito de campo que atua no sentido contrário. Na 2-etiltio-2-ciclopentenona ocorre uma estabilização adicional, por delocalização eletrônica, do orbital π*, quando os grupos SR e CO acham-se ligados conjuntamente à dupla ligação. / The present thesis investigates the electronic interactions in some cyclic ketones, α-sulphur substituted by comparison with the corresponding sulphur-free compounds. The compounds studied were: cyclopentanone (I), mercaptocyclopentanone (II), 2-methylthiocyclopentanone (III), 2-ethylthiocyclopentanone (IV), 2-n-propylcyclopentanone (V), camphor (VI), 2-ethylcamphor (VII), 2-methylthiocamphor (VIII), cyclohexanone (IX), 2-methylcyclohexanone (X), 2-ethylthiocyclohexanone (XI), 2-hexanone (XII), ethylthioacetone (XIII), 3-thiacyclopentanone (XIV), 3-thiacyclohexanone (XV), 2-cyclopentenone (XVI), 2-ethylthio-2-cyclopentenone (XVII), l-ethylthiocyclopentene (XVIII), cyclopentene (XIX), cyclopentanethiol (XX) and ethylthiocyclopentane (XXI) (ver arquivo). The literature reports are presented on electronic interactions in the β-thia-substituted carbonyl compounds and in the vinyl- and aryl-thioethers. The syntheses of the compounds (II)-(V), (VII) , (XVI)-(XVIII), (XX) and (XXI) are described. The basicity constants for ketones (I)-(XVII) and the ultraviolet spectra for compounds (I)-(III), (XVI)-(XXI) are reported. The experimental results indicate that: 1 - All sulphur substituted carbonyl compounds show a decrease in basicity in comparison with the corresponding unsubstituted compounds. However, the extent of this decrease is not the same for all compounds studied. 2 - The η → π* and π → π* absorption bands in the spectrum of the 2-ethylthio-2-cyclopentenone (XVII) undergo bathocromic shifts in comparison with the saturated cyclanones and cyclopentenes, respectively. However, the ηs → σ* band is similar to those for thioethers and thiols. The results suggest that: The decrease of basicity depends on the position of C-S bond towards carbonyl group, being of maximum value when the projected angle Φ approaches 0 or 180°. The decrease of basicity is due to through-space and/or through bond interaction between the lane pairs on sulphur and oxygen atoms. The decrease of basicity in the planar 2-ethylthio-2-cyclopentenone is partly cancelled by a field effect operating in the reversed direction. In the 2-ethylthio-2-cyclopentenone a additional stabilization takes place, wich is due to electronic delocalization of π* when the SR and CO groups are bonded to the double bond.
2

Sobre as interações eletrônicas em algumas ciclanonas e em 2-ciclopentenona, substituídas em α por um átomo de enxofre / About electronic interactions and in some ciclanonas 2-cyclopentenone, α substituted by a sulfur atom

Isabel Cristina Coelho Calegao 23 January 1981 (has links)
Este trabalho investiga as interações eletrônicas em algumas cetonas cíclicas, substituídas em α por um átomo de enxofre, pela comparação com os compostos substituídos correspondentes. Os compostos estudados eram: ciclopentanona (I), 2-mercaptociclopentanona (II), 2-metiltiociclopentanona (III), 2-etiltiociclopentanona (IV), 2-n-propilciclopentanona (V), cânfora (VI), 2-etilcânfora (VII), 2-metiltiocânfora (VIII), ciclohexanona (IX), 2 -metilciclohexanona (X), 2-etiltiociclohexanona (XI), 2-hexanona (XII), etiltioacetona (XIII), 3-tiaciclopentanona (XIV), 3-tiaciclohexanona (XV), 2-ciclopentenona (XVI), 2-etiltio-2-ciclopentenona (XVII), l-etiltiociclopenteno (XVIII), ciclopenteno (XIX), ciclopentanotiol (XX) e etiltiociclopentano (XXI) (ver arquivo). São apresentadas as revisões bibliográficas sobre interações eletrônicas em compostos carbonílicos β-tia-substituídos e em vinil- e aril-tioéteres. São descritas as sínteses de compostos (II)-(V), (VII), (XVI)-(XVIII), (XX) e (XXI) por nós efetuadas. São apresentadas as constantes de basicidade de cetonas (I)-(XVII) e as medidas no ultravioleta de compostos (I-III), (XVI)-(XXI). Os dados experimentais indicam que: 1 - Todos os compostos carbonílicos contendo enxofre apresentam basicidade menor em relação aos compostos correspondentes não sulfurados. Entretanto, a grandeza desta diminuição não é a mesma para todos os compostos estudados. 2 - As bandas η → π* e π → π* do espectro no ultravio1eta de 2-etiltio-2-ciclopentenona (XVII) sofrem deslocamentos batocrômicos em comparação com as ciclanonas saturadas e ciclopentenos, respectivamente. Entretanto, a banda ηs → σ* é semelhante a de tioéteres e tióis. É apresentada uma discussão dos resultados obtidos, na qual sugere-se que: A diminuição da basicidade depende da posição da ligação C-S em relação ao grupo carbonila, sendo maior quando o ângulo de projeção Φ se aproxima de 0 ou 180°. A diminuição de basicidade é devida a interação no espaço e/ou através das ligações entre os pares de elétrons do enxofre e oxigênio carbonílico. A pequena diminuição de basicidade observada em 2-eti1tio-2-ciclopentenona de conformação plana é proveniente do cancelamento parcial do efeito da interação pelo efeito de campo que atua no sentido contrário. Na 2-etiltio-2-ciclopentenona ocorre uma estabilização adicional, por delocalização eletrônica, do orbital π*, quando os grupos SR e CO acham-se ligados conjuntamente à dupla ligação. / The present thesis investigates the electronic interactions in some cyclic ketones, α-sulphur substituted by comparison with the corresponding sulphur-free compounds. The compounds studied were: cyclopentanone (I), mercaptocyclopentanone (II), 2-methylthiocyclopentanone (III), 2-ethylthiocyclopentanone (IV), 2-n-propylcyclopentanone (V), camphor (VI), 2-ethylcamphor (VII), 2-methylthiocamphor (VIII), cyclohexanone (IX), 2-methylcyclohexanone (X), 2-ethylthiocyclohexanone (XI), 2-hexanone (XII), ethylthioacetone (XIII), 3-thiacyclopentanone (XIV), 3-thiacyclohexanone (XV), 2-cyclopentenone (XVI), 2-ethylthio-2-cyclopentenone (XVII), l-ethylthiocyclopentene (XVIII), cyclopentene (XIX), cyclopentanethiol (XX) and ethylthiocyclopentane (XXI) (ver arquivo). The literature reports are presented on electronic interactions in the β-thia-substituted carbonyl compounds and in the vinyl- and aryl-thioethers. The syntheses of the compounds (II)-(V), (VII) , (XVI)-(XVIII), (XX) and (XXI) are described. The basicity constants for ketones (I)-(XVII) and the ultraviolet spectra for compounds (I)-(III), (XVI)-(XXI) are reported. The experimental results indicate that: 1 - All sulphur substituted carbonyl compounds show a decrease in basicity in comparison with the corresponding unsubstituted compounds. However, the extent of this decrease is not the same for all compounds studied. 2 - The η → π* and π → π* absorption bands in the spectrum of the 2-ethylthio-2-cyclopentenone (XVII) undergo bathocromic shifts in comparison with the saturated cyclanones and cyclopentenes, respectively. However, the ηs → σ* band is similar to those for thioethers and thiols. The results suggest that: The decrease of basicity depends on the position of C-S bond towards carbonyl group, being of maximum value when the projected angle Φ approaches 0 or 180°. The decrease of basicity is due to through-space and/or through bond interaction between the lane pairs on sulphur and oxygen atoms. The decrease of basicity in the planar 2-ethylthio-2-cyclopentenone is partly cancelled by a field effect operating in the reversed direction. In the 2-ethylthio-2-cyclopentenone a additional stabilization takes place, wich is due to electronic delocalization of π* when the SR and CO groups are bonded to the double bond.
3

Temporal Subordinators and Clauses in Early Modern English : Stability and Change

Rönnerdal, Göran January 2017 (has links)
My work is a corpus-based investigation of the use and development of temporal subordinators and clauses in Early Modern British English (EModE).  The focus of the project is on the forms, structure, meanings, and history of these subordinators and clauses. My primary aim is to analyse stability and change in temporal subordinators and clauses across the EModE period; second comes the study of linguistic features, such as aspect, tense, mood and modality, ellipsis and non-finite forms, positions, coordination, and subordination of the temporal clauses. In addition, I examine the progress of these subordinators, and WHEN in particular, across text categories, text types, and the sub-periods. Regarding temporal subordinators, I account for the use of simple, complex, and correlative forms. I also address alternative expressions of temporal subordinators such as the repetition and replacement of temporal subordinators. The influence of negation on the choice of subordinators, and the modification patterns of subordinators are also treated. Primary meanings of anteriority, simultaneity, and posteriority as well as secondary meanings of temporal subordinators are studied. I uncover the evolution of temporal subordinators and trace their various forms, as far back as possible to the Old English and Middle English periods. I also make some comparisons with Present-day English. The investigation is based on the EModE section of the computerized Helsinki Corpus of English Texts and the manual literary Major Authors Corpus which I designed for the purposes of the study. Consequently, my study is carried out within corpus linguistics methodology. All in all, the primary material yielded 3,269 instances of 17 different prototypical temporal subordinators, called sub-types.
4

論4.0高科技發展策略對未來工作型態及種類之影響及因應-以量販流通業R公司為例 / The study of the 4.0 High-Tech Strategy’s impacts and responses on future work styles and types - the case of R retailing company

洪冠宇 Unknown Date (has links)
近年來,先近諸國無不提出各自版本的「4.0高科技發展策略」,在此先進科技架構下,過去不斷討論的「機器取代人力」的爭論再次浮現。本研究將探討的是:在不久後的將來,4.0高科技發展策略的科技發展是否會威脅人們的工作?又,哪些工作可能被取代?以及工作模式會產生哪些改變?另外,在前述工作的轉變下,企業及社會制度(法政策)應做好怎樣的準備?   本研究由先進諸國對此議題的探討以及政策目標著手,統整包括各國以4.0高科技發展策略的四大核心科技所訂下的策略,以及各領域專家對科技造成工作種類(哪些工作會消失或改變)及型態(勞動彈性化、遠距工作、獨立的知識工作者)轉變的看法、對法政策層次造成的衝擊,接著由前述文獻探討的結果,自行統整出的框架,以套用在台灣現況。   前述分析完成後,則聚焦台灣,從產業、社會狀況及政策等層次分析台灣是否已經準備好迎接這波浪潮,以及台灣有何優勢劣勢等。最後,訪談企業個案,並了解以下議題:企業使用4.0高科技發展策略的科技狀況、企業個案對未來的規劃與預測以及個案認為台灣社會應做的準備,並套用上述的各國及台灣文獻分析結果,提出針對企業個案的建議:包括判斷企業內的哪些工作能在新科技介入後更有效率,具體判斷程序為何?以及對個案形塑未來科技化職場的短程及長程建議等。根據上述企業所做的調整建議,亦可提供台灣社會反思的機會,並在研究的最後提出對這波自動化浪潮台灣所應做的準備,在法政策面向上尚有哪些不足。   本研究分析由各學者提出的理論,統合意見後認為:企業層次方面,在資源有限的狀況下,面臨4.0高科技發展策略科技導入議題的取捨時,應描繪出未來的企業的圖像,方能明確目標,以量販流通業個案為例:應思索要側重電商自動化或是實體賣場無人化,方有助於排定先後順序,以集中資源提升企業競爭力,行有餘力,則可兩者兼顧;為協助前項建議,本研究提出3W分析法,建議企業就工作說明書進行分析,統整出哪些工作較具有被取代的潛力、時程如何,套用3W分析法的優點在於,企業可思索那些工作可由科技優化,讓企業更能綜觀企業內勞動力狀況,明確策略目標的同時,以漸進式的手法導入科技,改變工作種類及型態,並且,亦可做為提供員工訓練設計的重要依據;至於在台灣社會方面,根據分析,在未來不同時程下,例行性、可預測性的工作將大受威脅,另外,勞動市場將可能變得懸殊化,在勞動法制的領域上應加強彈性安全的勞動市場模式,可參考先進國家的做法,並進一步思索未來無條件基本收入制的可行性。

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