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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

De nouveaux biocatalyseurs hétérogènes pour des réactions d'oxydation : des cristaux de métalloenzymes artificielles / New heterogeneous biocatalysts for oxidation reactions : crystals of artificial metalloenzymes

Lopez, Sarah 12 October 2018 (has links)
Depuis la révolution industrielle, la chimie ne cesse de prospérer en développant des procédés de plus en plus performants souvent aux dépens de l’environnement. Dans le cadre du développement d’une chimie durable, des procédés catalytiques dans le domaine de la chimie d’oxydation sont mis en place en utilisant des métaux physiologiques et des oxydants doux. En combinant les avantages de la catalyse homogène et de la biocatalyse, de nouveaux catalyseurs bio-inspirés ont émergé, les métalloenzymes artificielles. Elles sont constituées d’un complexe inorganique, choisi en fonction de la réaction visée, qui est ancré au sein d’une protéine, qui apporte la sélectivité de la réaction. Au cours des travaux de cette thèse, de nouvelles métalloenzymes artificielles ont été créées par ancrage de divers complexes de Fe ou de Ru au sein de la protéine NikA. Dans un premier temps, l’hybride NikA/Ru-bpza a été synthétisé pour réaliser l’hydroxychloration d’alcènes en présence d’un iode hypervalent. Bien que d’excellentes propriétés catalytiques aient été obtenues, l’amélioration de la stabilité de ce type de catalyseurs, en particulier pour des réactions d’oxydation, reste un challenge important à relever pour leur utilisation au niveau industriel. Une des solutions originale est basée sur le développement de la catalyse hétérogène, en utilisant de cristaux de métalloenzymes artificielles grâce à la technologie CLEC (Cross-Linked Enzyme Crystals). Cette technologie permet, d’une part, d’améliorer la stabilité et la recyclabilité des catalyseurs, et d’autre part, d’élargir les conditions réactionnelles utilisées (solvants, pH, températures). Trois réactivités ont été développées à base de CLEC NikA/FeL : (i) la sulfoxydation de thioéthers, (ii) l’hydroxychloration d’alcènes en présence d’Oxone® et de chlore et (iii) la coupure oxydante d’alcènes par activation d’O2. Ces résultats ont permis d’explorer de nouvelles réactivités en chimie cascade soit en combinant les CLEC mis au point, soit en combinant différents catalyseurs homogènes. / Since the industrial revolution, chemistry has continually thriven by developing new efficient processes at the expense of the environment. As an example, oxidation reactions are performed under harsh conditions with the use of toxic oxidants. With the emergence of green chemistry, catalytic processes using physiological metals and soft oxidants are privileged. Combining the advantages of biocatalysis and homogeneous catalysis, the design of novel bioinspired catalysts, consisting on the synthesis of artificial enzymes has recently emerged. These hybrids are composed of an inorganic complex, driving the reactivity of the enzyme, inserted into a protein, which drives the reaction selectivity. The thesis described new developments in original artificial metalloenzymes, based on the use of the NikA protein and Fe or Ru catalysts. First, a new hybrid has been developed by anchoring the Ru-bpza complex to NikA to catalyze alkene hydroxychloration with hypervalent iodine. Although excellent catalytic efficiencies were obtained, the stability improvement remains a major challenge for the industrial use of these catalytic processes, especially when oxidation chemistry is concerned. One possible strategy is based on the development of heterogeneous catalysis, by using a crystal/solution version of the artificial metalloenzymes thank to the cross-linked enzyme crystals (CLEC) technology. On the one hand, this technology allows to increase the stability and the recyclability of the catalysts. On the other hand, catalysis can be performed under a various reactions conditions (organic solvent, temperature, pH). Three reactivities have been developed with NikA/FeL-CLEC catalysts: (i) thioether sulfoxidation with NaOCl, (ii) alkene hydroxychloration with Oxone® and chloride source and (iii) oxidative cleavage of alkenes by O2 activation. To go further, new reactivities in cascade reactions have been explored combining either NikA-based CLEC developed, or different homogenous catalysts.
2

新世代電信級網路電話(VoIP)客戶服務之研究 / The study of customer service for carrier grade next generation network (VoIP)

徐志得, Hsu, Heigen Unknown Date (has links)
在電信獨占市場的時代,語音及訊務都架設在TDM (時間分割多工)的系統上,其客戶服務比新世代網路系統較為簡易。1997年,政府開放行動電話營運執照申請,在2008年第一季末,手機門號(包含2G+PHS+3G)幾乎與人口(2300萬戶)ㄧ樣多。2000年,政府開放固網執照申請,因為固網路鋪設到last-mile的速度緩慢及成本較高,「新進業者」(CLEC)比「既有經營者」(ILEC)較不具備競爭力,加上無killer application (殺手級應用)及差異性的客服,因此至今CLEC沒有爭取到太多的顧客,一直到Skype進入台灣,大家才看到電信語音市場另一塊新版圖。 近年來VoIP (Voice Over IP)技術進步,將通訊協定信號(SIP)與媒體語音訊務(RTP/RTCP)分開處理。因此,全世界各通信製造業者及服務商(SP)開始運用此技術在行動電話多媒體服務及IP多媒體子系統(IMS)的架構上。不僅如此,有很多網路用戶與互聯網企業也因為開始分享資訊,造成一些新興內容產業--(UGC用戶產生內容、SNS社會網絡服務) 的誕生。所以預料在新世代電信網路(NGN)新科技的環境之下,將會有不少新興產業如海星組織一般的誕生、滋長及蔓延,這對電信業者、服務供應商及用戶將會帶來更多維護及服務的衝擊。 因此本研究將參考現有電信客戶服務跟未來20年通信技術,建議如何使用混合式(集權/分權)的客戶服務來協助電信級固網業者及服務開發者去創造企業價值、突破現有困境、達到永續經營的目的,以因應未來電信自由化及新電信技術。 / In the monopoly era, the telecom network was implemented on TDM (Time Division Multiplexer) system, whose customer service of voice call is comparatively simpler and easier than NGN (Next Generation Network) system. In 1997, government opened the application of mobile network operation license. By end of 1Q of 2008, the subscriber count (includes 2G, PHS and 3G) of mobile network was almost as many as population (23 millions). In the year of 2000, government opened the application of fixed network operation license. Because of the slower speed and higher cost of last-mile network implementation, up to now, new Competitive Local Exchange Carriers (CLEC) were less competitive than Incumbent Local Exchange Carrier (ILEC). Plus, not having the killer-application and the differentiated customer services, CLECs did not have too many subscribers in these years. Until Skype was introduced to Taiwan, all of us, then, saw the other new territory of voice telecom market. These years, VoIP (Voice over IP) technology was improved to have communication protocol (SIP Session Initialization Protocol) and voice traffic (RTP/RTCP Real-time Transport Protocol/Real-time Transport Control Protocol) been handled separately; i.e., the development of voice application software and debug became easier. Thus, the world-wide telecom manufacturers and service providers started to use this technology on the architecture of mobile voice multimedia service and IP Multi-media Subsystem (IMS). Even amount of network users were sharing information with enterprises who owned inter-connection network, and created the new content businesses (UGC User Generated Content, SNS Social Network Services). Therefore, under the new technology environment of NGN, we foresee some new businesses will be created, then, growing and expanding like the starfish organization. For telecom operators, service providers and users, this will bring some more new impacts of maintenance and service. Therefore, this study will refer the existing telecom customer service and the telecom technologies may have in next coming 20 years to propose how to use the hybrid (centralized/de-centralized) customer service to help both carrier-grade fixed network operators and service developers to create business value, break through current dilemma to reach business continuity goal in response to the telecom liberalization and new telecom technologies.
3

利用4C架構解析寬頻接取技術廠商之競爭策略-以系統設備供應商角度切入

楊國南, Yang, Remy Unknown Date (has links)
本研究主旨在探討有線的光纖通訊與無線的行動通訊接取網路設備供應商在市場所面臨的嚴峻考驗,在面對彼此的競爭下,各廠家利用不同的市場策略,如何在激烈的環境中脫穎而出。因為國際規範標準化的緣故,使得利用策略行銷4C成本理論比較起傳統市場行銷之4P理論來分析更為有趣且貼切,因此探討以策略行銷4C成本理論為基礎。對於接取網路的通訊設備供應商而言,各有其特別之技術屬性、先天的優勢、網路資源與客戶群,甚至利用國家資源,進而掌握現有的客戶群;然而一些新進業者,為了開拓新的客戶群,在策略行銷4C的成本理論基礎下,如何自訂最有利的市場行銷策略,並加以活用,使得對於外顯單位效益成本、資訊搜尋成本、道德危機成本與專屬資產陷入成本的認知,各有不同的考量與評估之方式,其目的是影響運營商最終採購之決定,並達到雙方相互陷入,最後取得市場上的優勢。

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