In this research, a novel low temperature atmospheric pressure plasma generator is successfully developed. The developed plasma generator can generate uniform plasma discharge under the operating conditions of 5 SLM helium flow rate and 5 Watts RF power. The temperature of the plasma generator can be maintained lower than 75oC after 30 minutes of continuous operation. The low temperature property of the proposed plasma generator is feasible for the high temperature sensitive sample. Modify the polymer surface by using this plasma generator, for example, the polydimethylsiloxane. It is successfully improve the hydrophilic property, and the surface energy changed obviously. The result of ATR-FTIR detection, the variation of functional groups proved the hydrophilic property, too. Being used the plasma generator to the ion source in novel mass spectrometry. Results show that the measured ion intensity generated using the proposed plasma generator increases steadily with the increases power and increases gas flow. This confirms that this plasma generator is a good ion source in mass spectrometry and for developing a Radio Frequency Direct Analysis in Real Time (RF-DART) mass spectrometry. The blown gas signals of the chewed gum, garlic, and tobacco can be detected quickly already. The signals of the volatile compounds in the solid Chinese herbs samples can be acquired, too. Mass-spectrometer detection results reveal that the developed low-temperature AP plasma generator can directly detect the sample peaks of various samples without using complicate sample preparation processes. More importantly, this proposed analysis method will not cause the memory effect which may influence the signal peaks while analyzing sequence samples during MS operation. Keywords: Low temperature atmospheric pressure plasma; Radio Frequency Direct Analysis in Real Time(RF-DART); Mass spectrometry; Memory effect.

This paper presents new bonding and surface modification methods for plastic substrates utilizing atmospheric pressure plasma (AP plasma) treatment. Three kinds of AP plasma equipments including after-glow discharge, dielectric barrier discharge and flame type are tested and evaluated for their feasibility of microfluidic device fabrication. The experimental results show that the DBD plasma equipment is the most suitable one for microfluidic applications due to its low temperature and high treating level. Three kinds of polymenr including PMMA, PC and PDMS are used as the sample substrates for evaluating the performance of AP plasma in this study. Experimental results show that the polymer surface turns into hydrophilic after AP plasma treatment. Fourier Transform Infrared Spectroscopy (FTIR) inspection indicates that a new peak corresponding to -C-OH functional group is generated at the wavenumber of 1040 cm-1 after AP plasma treatment. X-ray photoelectron spectrum investigation also shows that the O/C (atom ratio) is 3.5-fold incensement in compare with the bare sample. SEM and AFM observations are utilized to evaluate the surface morphology change after plasma treatment. The measured surface roughness is at the level of several nanometers which is acceptable for most microfluidic applications. We develop two simple and high strength bonding methods for sealing microfluidic deivices in this study. The bonding process can be achieved in 6 minutes and bonding strength of 1.69 MPa and 3.81 MPa can be obtained using direct plasma bonding and ethyl alcohol assisted bonding, respectively. The bonding strength obtained using ethyl alcohol assisted bonding technique reported in this study is the highest one that ever been reported. The feasibility of AP plasma treatment for sealing microfluidic chips are confirmed by three examples including two novel passive microfluidic mixers and one cross-type micro CE chip. Experimental result shows that the mixing performance of the micromixer can reach up to 90% at an operation condition of a low Reynolds number of 4. In addition, micro CE chip sealed with the proposed method can successfully inject and separate dye sample with a long-term stability upto 30 minutes. Separation of 100 bp standard DNA sample of 100 bp to 3000 is also successfully demonstrated with high separation efficiency. It is the author¡¦s firm believes that the proposed bonding method will give substaintial impact on the fabrication of microfluidic device in the future.

Plasma-assisted processing and deposition of materials is an important component of modern industrial applications, with plasma reactors sharing 30% to 40% of manufacturing steps in microelectronics production [1]. Development of new flexible electronics increases demands for efficient high-throughput deposition methods and roll-to-roll processing of materials. The current work represents an attempt of practical design and numerical modeling of a plasma enhanced chemical vapor deposition system. The system utilizes plasma at standard pressure and temperature to activate a chemical precursor for protective coatings. A specially designed linear plasma head, that consists of two parallel plates with electrodes placed in the parallel arrangement, is used to resolve clogging issues of currently available commercial plasma heads, as well as to increase the flow-rate of the processed chemicals and to enhance the uniformity of the deposition. A test system is build and discussed in this work. In order to improve operating conditions of the setup and quality of the deposited material, we perform numerical modeling of the plasma system. The theoretical and numerical models presented in this work comprehensively describe plasma generation, recombination, and advection in a channel of arbitrary geometry. Number density of plasma species, their energy content, electric field, and rate parameters are accurately calculated and analyzed in this work. Some interesting engineering outcomes are discussed with a connection to the proposed setup. The numerical model is implemented with the help of high-performance parallel technique and evaluated at a cluster for parallel calculations. A typical performance increase, calculation speed-up, parallel fraction of the code and overall efficiency of the parallel implementation are discussed in details.

Cold plasma is useful in numerous medical applications, largely because of the highly-reactive chemical species generated in the discharge. The hydroxyl radical (OH) is of these species and has significant biological importance. An atmospheric pressure plasma jet (APPJ) was constructed in the form of a plasma pencil, and relative and absolute measurements were made of OH in both its first excited ground state—OH(A) and OH(X), respectively—using optical emission spectroscopy and cavity ring-down spectroscopy (CRDS). The total number of OH radicals were found to be constant in the plume and within the range given by relative measurements made on similar devices in the literature.

<div>Plasmas can be used to increase the probability of maturity of seeds and disinfect them. The water applied on plants can also be treated with plasma to reduce bacteria. Discharges normally used to treat water including dielectric barrier discharges, gliding arcs, DC, AC, or pulsed coronas, and various direct discharges in liquid. After treatments, reactive oxygen (ozone) and nitrogen species (nitrite and nitrate) will appear in the water solution. Then, by applied this water, the lifecycle of plant could be significantly influenced. Plasma has a great potential to play an important role in the agriculture discipline. The process of synthesizing nitrate fertilizer with water, air, and electric spark has been known for a long time. But due to low nitrate yield and high energy consumption, it was replaced by the Haber-Bosch process in the first half of the 20th century. The Haber-Bosch process, however, has several disadvantages: it requires natural gas as a raw material, fixes nitrogen in the form of ammonia, and generates oxycarbides as byproducts. Thus, the concept of manufacturing nitrogen fertilizer with only water, air and electricity is still appealing.</div><div><br></div><div>In this project, we want to measure the pH value and conductivity of the water treated by various atmospheric pressure discharges including the arc discharge, DC positive corona discharge, DC voltage driven cold plasma torch operating with helium, dielectric barrier discharge (DBD), and radio-frequency (RF) plasma. Also, it is necessary to verify the existence of different important species in the treated water such as peroxide, nitrite, and nitrate ions by measuring their concentrations. Based on current and voltage measurements and wall-plug electrical energy consumption, energy efficiency of nitrate synthesis was determined in these five plasma systems. Optical emission spectroscopy was employed to study the reaction kinetics of both DBD and RF discharge. Our goal is to produce enough nitrate ions, by plasma treatment with minimal energy input (the value should be at least close to the Haber-Bosch process), in water which could be further used as fertilizers.</div><div><br></div>

Τα λιποσώματα αναπτύχθηκαν αρχικά από τον Alec Bangham το 1964. Έκτοτε μελετώνται τόσο ως φορείς βιοδραστικών ενώσεων όσο και ως μοντέλα βιολογικών μεμβρανών με σκοπό την αποσαφήνιση της δομής και των λειτουργιών τους. Αυτό οφείλεται στο γεγονός ότι αποτελούνται από τα ίδια δομικά συστατικά με εκείνα των βιολογικών μεμβρανών και η ευελιξία της δομής τους προσφέρει τη δυνατότητα προσομοίωσης της δομής και σύστασης διαφορετικών βιολογικών μεμβρανών. Στις εφαρμογές του ψυχρού πλάσματος ατμοσφαιρικής πίεσης, cold atmospheric pressure plasma (CAPP), που μελετώνται τα τελευταία χρόνια συγκαταλέγονται και βιοιατρικές εφαρμογές. Συγκεκριμένα μελετάται η χρήση του ως μέσω απολύμανσης και αποστείρωσης, στην ανάπλαση δέρματος, ως αντικαρκινική θεραπεία κ.τ.λ. Εντούτοις ο ακριβής μηχανισμός της αλληλεπίδρασης του ψυχρού πλάσματος ατμοσφαιρικής πίεσης με κύτταρα και ιστούς δεν είναι ακόμα πλήρως κατανοητός. Παρότι οι μέχρι τώρα μελέτες για την αποσαφήνιση της αλληλεπίδρασης αυτής πραγματοποιούνται με την χρήση κυτταρικών καλλιεργειών, η χρήση λιποσωμάτων είναι μια πιθανή εναλλακτική. Αυτό οφείλεται στο γεγονός ότι η χρήση λιποσωμικών διασπορών, ως μοντέλα κυττάρων, έχει αποδειχθεί μια πιο εύκολη, ταχύτερη και χαμηλότερου κόστους εναλλακτική των κυτταρικών καλλιεργειών για την αποσαφήνιση βιολογικών διεργασιών. Η παρούσα εργασία έχει ως σκοπό τη διερεύνηση της δυνατότητας χρήσης των λιποσωμάτων ως μοντέλα βιολογικών μεμβρανών για την μελέτη της αλληλεπίδρασης του CAPP με κύτταρα. Μελετήθηκε η αλληλεπίδραση λιποσωμάτων – CAPP και επιχειρήθηκε η παραμετροποίηση της αλληλεπίδρασης αυτής. Τα λιποσώματα, που εγκλωβίζουν υδατικό διάλυμα καλσεΐνης, παρασκευάσθηκαν με την τεχνική της ενυδάτωσης λεπτού υμενίου και έγινε χρήση υπερήχησης με σκοπό την μείωση του μεγέθους τους. Τα λιπίδια που χρησιμοποιήθηκαν ήταν: φωσφατιδυλοχολίνη, φωσφατιδυλογλυκερόλη και χοληστερόλη. Υπέστησαν επεξεργασία τόσο με CAPP όσο και με αφόρτιστο φέρον αέριο. Ο χαρακτηρισμός των λιποσωμάτων έγινε μέσω μέτρησης των φυσικοχημικών τους χαρακτηριστικών. Ως μέτρο της αλληλεπίδρασης CAPP-λιποσωμάτων χρησιμοποιήθηκε η μεταβολή του εγκλωβισμού της καλσεΐνης. Επιπλέον πραγματοποιήθηκε μορφολογική ανάλυση των λιποσωμάτων, μέσω ηλεκτρονιακής μικροσκοπίας σάρωσης, πριν και μετά την επεξεργασία. Με σκοπό την παραμετροποίηση της αλληλεπίδρασης αυτής έγινε μελέτη της μεταβολής των φυσικοχημικών ιδιοτήτων των λιποσωμάτων ως συνάρτηση του χρονικού διαστήματος επεξεργασίας και του χρόνου επώασης (σε PBS στους 4C) μετά την επεξεργασία. Επιπλέον πραγματοποιήθηκαν πειράματα αλληλεπίδρασης του CAPP με κύτταρα B-16, καρκινικά κύτταρα μελανώματος ποντικού. Ως οι κυριότεροι παράγοντες της αλληλεπίδρασης CAPP – λιποσωμάτων διαφαίνονται η συγκέντρωση της λιποσωμικής διασποράς και ο χρόνος επεξεργασίας. Η μείωση του ποσοστού εγκλωβισμού της καλσεΐνης αυξάνεται ανάλογα με την αύξηση τόσο της συγκέντρωσης όσο και του χρόνου επεξεργασίας. Επιπλέον η λιπιδική σύσταση επηρεάζει το αποτέλεσμα της αλληλεπίδρασης. Η ύπαρξη αρνητικού επιφανειακού φορτίου επηρεάζει θετικά το αποτέλεσμα της αλληλεπίδρασης ενώ η ύπαρξη χοληστερόλης οδηγεί σε πιο ανθεκτικά λιποσώματα μόνο στη μέγιστη συγκέντρωση (50%). Μείωση του μεγέθους και του αριθμού των διπλοστιβάδων των λιποσωμάτων οδηγεί σε πιο ευαίσθητα κυστίδια. Διαφυγή της καλσεΐνης παρατηρήθηκε μέχρι και 96 ώρες μετά την επεξεργασία ενώ με το πέρας του χρόνου παρατηρήθηκε επιπλέον συσσωμάτωση των κυστιδίων, το οποίο επιβεβαιώνεται με μορφολογικές μελέτες, και μεταβολή τους επιφανειακού τους φορτίου. Η επίδραση του CAPP στα κύτταρα Β-16 επηρεάζεται τόσο από την αρχική πληρότητα (confluence) της καλλιέργειας όσο και από τις διαστάσεις των κελιών της χρησιμοποιούμενης πλάκας. Παρότι η ανωτέρω ανάλυση υποστηρίζει την αρχική υπόθεση, απαιτείται περαιτέρω διερεύνηση της αλληλεπίδρασης του CAPP με βιολογικά δείγματα. / Liposomes were originally developed by Alec Bangham in 1964. Since then, they have been studied as carriers of bioactive compounds and as biological membrane models in structural and functional studies. This is due to the fact that they are composed of the same building blocks as biological membranes and because their structural versatility offers the opportunity to create vesicles that resemble the structure and composition of different biological membranes. In recent years cold atmospheric pressure plasma, CAPP, has been studied for a variety of applications some of which are found in the biomedical milieu. More precisely these applications include: decontamination, sterilization, skin regeneration, tumor treatment, etc. Nevertheless the exact mechanism of the interaction between CAPP and cells/tissue is not yet completely understood. Although currently researchers use cell cultures to investigate this interaction, liposomes could be an alternative. The applicability of liposomal dispersions, as cell models, has proved to be an easier, faster and less expensive tool for the investigation of cell – cellular environment interactions. The purpose of this thesis was to investigate the possibility of using liposomes as cell membrane models to study the CAPP-cells interactions. The CAPP-liposomes interaction was studied and parameterization of this interaction was attempted. Calcein-encapsulating liposomes were prepared using the thin-film hydration technique and the sonication technique was used to decrease the size of the vesicles. The lipids used were: phosphatidylcholine, phosphatidylglycerol and cholesterol. The samples were treated both with CAPP and with the uncharged carrier-gas. Characterization of liposomes was made by measuring their physicochemical characteristics. The variation of the percent of calcein encapsulation was used to measure the effect of CAPP-liposomes interaction. Moreover morphological evaluation of the samples before and after treatment was realized thought scanning electron microscopy, SEM. The variation of liposomes’ physicochemical characteristics versus time, duration of treatment and incubation (in PBS at 4C), was realized in order to parameterize this interaction. The effect of CAPP on B-16 cells, mouse melanoma cancer cells, was also investigated. The major parameters of the CAPP-liposomes interaction were proved to be the concentration of the liposomal dispersion and the duration of treatment. The increase of both the lipid concentration and the duration of treatment lead to increase of the reduction of calcein’s encapsulation provoked by CAPP treatment. The composition of the liposomal membrane also affects the interaction’s result. Negative surface charge increases the impact of CAPP and the presence of cholesterol leads to more stable structures only when its concentration is maximum (50%). Reduction of the size and lamellarity of the vesicles leads to more fragile liposomes. Release of calcein was observed even 96 hours after treatment in combination with aggregation of the vesicles, which was also proved via morphological evaluation, and change of liposomes’ surface charge. The impact of CAPP treatment on B-16 cells seems to depend on the initial confluence of the culture as well as the dimensions of the plate’s wells. Although the aforementioned analysis supports the initial hypothesis, further investigation of the interaction between CAPP and biological samples is necessary.

The 'high-pressure' atmospheric (TIG) arc plasma is studied by means of a multi-Langmuir probe system. In order to determine the appropriate regime of operation, definitions of the plasma parameters for the description of the argon arc are considered and evaluations are presented. A description of the probe basic techniques is followed by an in-depth discussion of the different regimes of probe operation. The emphasis is put on atmospheric and flowing (arc) regimes. Probe sheath theories are compared and “Nonidealities” like cooling due to plasma-probe motion and probe emission mechanisms are then described. The extensive literature review reveals that the existing probe theories are inappropriate for a use in the TIG arc, because of ‘high’ pressure (atmospheric), broad range of ionization across the arc, flowing conditions, and ultimately, to the uncertainty about onset of Local Thermodynamical Equilibrium. The Langmuir probe system is built to operate in floating and biased conditions. The present work represents the first extensive investigation of electrostatic probes in arcs where the experimental difficulties and the primary observed quantities are presented in great detail. Analysis methodologies are introduced and experimental results are presented towards a unified picture of the resulting arc structure by comparison with data from emission spectroscopy. Results from different measurements are presented and comparison is made with data on TIG arcs present in literature. Probe obtained temperatures are lower than the values obtained from emission spectroscopy and this ‘cooling’ is attributed to electron-ion recombination. However, it is believed that probes can access temperatures regions not attainable by emission spectroscopy. Only axial electric potential and electric field are obtained because of the equipotential-probe requirement. Estimations of the sheath voltage and extension are obtained and a qualitative picture of the ion and electron current densities within the arc is given.

Submitted by ALONSO HERNAN RICCI CASTRO null (alonso_elfisico@yahoo.com) on 2017-08-17T17:22:54Z No. of bitstreams: 1 Castro_AHR_PHD.pdf: 57242725 bytes, checksum: 36378feb1c1464a31ab9ed5824539173 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-08-23T17:50:32Z (GMT) No. of bitstreams: 1 castro_ahr_dr_guara.pdf: 57242725 bytes, checksum: 36378feb1c1464a31ab9ed5824539173 (MD5) / Made available in DSpace on 2017-08-23T17:50:32Z (GMT). No. of bitstreams: 1 castro_ahr_dr_guara.pdf: 57242725 bytes, checksum: 36378feb1c1464a31ab9ed5824539173 (MD5) Previous issue date: 2017-06-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho teve como objetivo o estudo dos parâmetros que influenciam o comportamento de um jato de plasma em pressão atmosférica e sua aplicação em deposição de filmes poliméricos. Com esta finalidade, foram utilizadas duas diferentes configurações de eletrodos em jatos de argônio: um de eletrodo anular externo e outro com eletrodo cilíndrico interno. Também foram utilizadas três geometrias diferentes de bocal de saída do jato (cônico fechado, reto e cônico aberto), usando um eletrodo cilíndrico interno. Os jatos de plasma de argônio operam em modo filamentar, com os filamentos se espalhando por todo o volume do tubo dielétrico, disposto coaxialmente ao eletrodo. Neste trabalho também foi desenvolvido um jato de plasma para a deposição de filmes poliméricos, constituído de um eletrodo de alta tensão em forma cilíndrica localizado no eixo longitudinal do jato, e um eletrodo aterrado na forma de anel que está fixado ao redor do bocal do jato. O estudo foi iniciado com a comparação de dois métodos utilizados para o cálculo da potência. Para os dois jatos de plasma observou-se que o método mais adequado para calcular a potência de descarga é o método da figura de Lissajous, que fornece um erro experimental menor que 3 %. Após realizar a caraterização elétrica dos jatos de plasma, pode-se observar que a potência e a forma de onda da corrente dependem de diferentes parâmetros, que são apresentados em ordem da maior a menor influência da distância bocal-substrato, do fluxo de gás, do tipo de substrato e da geometria do bocal. A deposição de filmes poliméricos foi influenciada pela geometria do jato de plasma e do fluxo dos gases. Os filmes depositados sem movimento do substrato apresentam uma taxa de deposição de 1 m/min. A análise XPS mostrou que os filmes são constituídos em sua maioria por grupos alifáticos C-C/C-H e em menor proporção por hidroxila, éster e ácido carboxílico. Mediante a implementação de uma plataforma móvel foi possível depositar filmes poliméricos em uma grande área, o que amplia a gama de aplicações dos jatos de plasma desenvolvidos neste trabalho. / The goal of this work was to study the parameters which influence the electrical behavior of a atmospheric pressure plasma jet and its application for polymeric films deposition. For this purpose, two different configurations of electrodes were used in argon jets: one with an external annular electrode and the other with an internal cylindrical electrode. Also, three different jet nozzle geometries were adopted using an internal cylindrical electrode: tapered nozzle, straight nozzle and enlarged nozzle. The argon plasma jets operate in filament mode, with the filaments spreading throughout the volume of the dielectric tube, arranged coaxially to the electrode. On this work, a plasma jet system was developed to deposit polymer films, this system consists of a cylindrical high voltage electrode located in the longitudinal axis of the jet, and a grounded electrode in the form of a ring that is fixed around the nozzle of the jet. The study started comparing both methods for calculation of the power of plasma jets. Afterwards, it was concluded that the best method was the Lissajous method giving 3 % of experimental error. After electrical characterization of the plasma jet it was found that the power and current were influenced by different parameters, presented in order of their importance: distance, gas flow, type of substrate and nozzle geometry. The polymer films deposition was influenced by the plasma jet geometry and the gas flow. The films deposited without movement have 1 m/min of deposition rate. The XPS analysis shows that the films are made mostly from aliphatic groups C-C/C-H and in lesser extension by hydroxyl, ester and carboxylic acid. Through implementation of mobile platform was possible to deposit polymer films over larger area.

A cold atmospheric pressure plasma source was investigated as an alternative pre-treatment for carbon fibre reinforced epoxy substrates prior to bonding. For reference, common surface pre-treatments were also investigated (peel ply, manual abrasion, and grit blasting). In the aerospace industry, the peel ply, is usually added to one side of the composite surface during manufacture and peeled off prior to bonding. Peel ply can be used independently or in combination with other techniques. The strength of the bonded joints of the different pre-treatments was assessed through tensile lap shear tests. It was found that combining peel ply with plasma increased the joint strength by 10% whereas manual abrasion or grit blasting after peel ply improved the strength of the joints by 15% and 20% respectively. The effect of pre-treating the composite substrate side without peel ply (bag side) was also investigated. The strength of the joints produced without any pre-treatment was increased by 99% for manual abrasion, 134% for grit blasting and by 146% for plasma. Comparing both surfaces of the composite substrates, it was found that using peel ply improved the performance of the joints by 91%. In order to understand better the effects of the different pre-treatments, surface characterisation of the substrates (surface roughness, surface free energy, and analysis of chemical changes) was also conducted. The effect of roughness did little to affect the strength values (for both surfaces of the composite). The adhesive used in this research was very good at wetting the surface, regardless of the roughness. However, when the adhesive was able to wet the surface, the relationship between bond strength and surface free energy was unclear. Plasma was shown to increase levels of oxygen at the surface and reduce/eliminate the concentration of fluorine at the surface on the bag side of the composite.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21756号 / 工博第4573号 / 新制||工||1713(附属図書館) / 京都大学大学院工学研究科機械理工学専攻 / (主査)教授 蓮尾 昌裕, 教授 木村 健二, 教授 江利口 浩二 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM