3,556 research outputs found

    Laser driven variable dot size thermal wax transfer printing

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    A digital image hardcopy device has been designed using a laser exposure mechanism, a pigmented wax /resin donor ink sheet, and an opaque receiver sheet. The writing system relies on image-wise thermal mass transfer of molten ink to the receiver in order to produce high resolution output. With the receiver media and a specially designed donor ribbon being held to a platen through vacuum pressure, a pulsed solid-state diode pumped near IR NdrYAG laser provides the energy necessary to complete the thermal transfer process. By varying pulse width, dot size variation is possible. A mathematical model was developed to explain the physics of the imaging process and aid further experimentation. In order to maximize photothermal conversion and transfer efficiency while maintaining environmental friendliness, a water/ alcohol based multi-layer donor ribbon was designed. Digital image analysis techniques and processing algorithms were developed specifically to provide a reliable quantification scheme for all variables. A randomized four factor central composite design provided a statistically robust means by which to map measured image quality. Response surface methods of factorial experimental design afforded a means to model the ribbon design space. Utilization of the Downhill Simplex Method (Nelder and Mead, 1965) yielded the optimum point on the estimated image quality response surface. The optimum point represented the final donor ribbon composition. It is primarily the continuously variable dot size capability and high thermal efficiency of the developed system that sets this research apart from other published works related to laser driven thermal transfer

    A Designer\u27s guide to the evaluation of digital proofs

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    Digital color proofs and pre-proofs are used by graphic artists and commercial printers throughout the prepress process. However the prepress process has undergone radical changes over the past decade due to the introduction of desk top publishing and desktop prepress. Alongside of the desktop publishing revo lution has come a multitude of new digital proofing technologies for use in this ever changing environment. Technologies including, but not limited to, liquid inkjet, dye sublimation, continuous inkjet, color laser, and thermal wax transfer printers have provided an entire range of color accuracy and price suitability to many of their users. However one needs to be able to understand the practical applications and limitations of these technologies to make a suitable choice for a specific prepress operation or design process. Therefore a handbook for the users of digital proofs has been created for their benefit. The underlying structure of this handbook is based on the following six chap ters. The first chapter, entitled Communicating with Prepress and the Attributes of Digital Proofing, contains multiple parts. Firstly, it contains information for the designer in regards to the advantages and disadvantages of all types of digital output devices. It discusses the advantages which digital output devices may or may not have over conventional proofing systems. Additionally, ideas such as the vantages and drawbacks of preproofers and proofers is elaborated upon. Information for this part of the chapter was obtained through questionnaires completed by, and interviews with print buyers, art directors, and production managers from advertising agencies and prepress providers in the Rochester area. More information for this section of the first chapter was obtained through various manufacturer\u27s literature, printing industry reports and various periodi cals. Chapter One also discusses ideas behind the application of color printers (preproofers) and digital proofers. These ideas address issues which pertain to the application of specific printing and proofing processes to specific phases of the creative and production processes. Additionally, discussions regarding proof ing costs, qualities, and production turnaround time may be found in this part of the first chapter. Information for this section of Chapter One was obtained through information found in printing and publishing related periodicals, as well as in manufacturers\u27 literature. Finally, the first chapter develops a system for the correction of digital preproofs and proofs. Multiple groups of ideas pertaining to the correction of digital output are discussed. Some of these include sections entitled Digital File Tracking and Identification, Evaluation of Design Elements, Evaluating Colors, Element Positioning, and Element Dimension Adjustments. Information for this part of the chapter was obtained through the evaluation of previously corrected digital con tract proofs and preproofs, as well as the interviews and questionnaires men tioned above. The second chapter, entitled Proofing Typography, displays the many different ways that printing and proofing technologies affect text type and display typog raphy. Using the CD-Rom included in the back of the book, one may view on screen how the following technologies affect type ranging from 3 points to 72 points in size: liquid inkjet, large format liquid inkjet, phase-change inkjet, ther mal wax transfer, dye sublimation, continuous inkjet, and dye ablation. Information and samples for this chapter were obtained through printing and proofing system manufacturers and advertising agencies in the Rochester area. The Color Primer and Chapter Three: Proofing for Imagery and Color, contain information for the designer which may be applied to proper evaluation of color on color prints and digital proofs. The Color Primer discusses subjects such as color space, the additive and subtractive color theories, and common color mea surement tools. Chapter Three then applies some of this knowledge in its discus sions of proper lighting conditions for viewing prints and proofs, and different human factors which influence the highly subjective evaluation of all digital color output. Information for this chapter was gathered using graphic arts and printing industry related periodicals and industry-wide books related to color and its reproduction. The fourth chapter, entitled Substrates and Digital Output, educates the design er about the effects on text, imagery, and graphics which occur when creating digital prints and proofs on a variety of papers. Various paper surfaces such as gloss, semi-gloss and matte surfaces are addressed. The affects of colored paper on imagery and graphics are also elaborated upon. Additionally, printing and proofing processes are discussed in regards to the substrates that they accept for output. Information for this chapter was gathered through manufacturers\u27 litera ture and various industry related books and periodical articles. The Proofing Process Supplement was created to familiarize the designer with all currently popular forms of digital output technology. The process supplement discusses the imaging processes used by the following digital output technolo gies: liquid inkjet, phase-change inkjet, thermal wax transfer, dye sublimation, continuous inkjet, and dye ablation. Additionally, the supplement contains brief explanations regarding screening technologies. Information for the process sup plement was gathered through manufacturers\u27 literature, interviews with pre press providers in the Rochester area, and interviews with technical representa tives from the manufacturers of devices which use the above digital, color out put technologies. Chapter Five, entitled Image Fidelity, simply illustrates how all of the current ly popular printing and proofing technologies affect graphics and imagery. Using the CD-Rom included with the guidebook, the reader may view magni fied and normal views of printing and proof sample imagery. Information noted by the reader in the proofing process supplement may then be actively applied when viewing these samples. Information and sample prints for the fifth chapter were gathered from several manufacturers and advertising agencies in the Rochester area. The sixth chapter, entitled The Acceptance of Digital Contract Proofing, discusses a new definition of the contract proof in regards to the evolution of digital proof ing. This chapter provides ideas for the designer, art director, and print buyer to realize when considering the use of digital contract proofing. Several questions are raised concerning what requirements a digital contract proof must fulfill depending upon the areas of its application and any agreements between the designer and prepress provider regarding their specific definition of a digital contract proof. Additionally, specific advantages of digital contract proofs, such as their ability to fingerprint a press and/or press run, are discussed. Finally, a discussion pertaining to the education of all users of digital proofing technolo gies is presented to aid the overall acceptance of digital contract proofing. Information for this chapter was obtained through the extensive interviews of leading technical and product oriented representatives from the manufacturers of currently used digital contract proofing systems. Many conclusions have been reached with the completion of this guidebook. In brief, the first and most prominent conclusion which may be reached states that the acceptance of digital contract proofing lies within the education of all designers, art directors and print buyers about digital printing and proofing technologies. As the use of digital contract proofing grows, education and inter est by all creative professionals will orient them towards their use of digital proofing systems. The next conclusion which has been reached is that the proper application of color printers and digital proofers is of major importance for the designer due to the added flexibility and rewards which result from the use of digital color out put devices throughout the creative and production processes. Another conclu sion which may be reached is that the display of proofing and printing process effects on text, graphics, and imagery serves to directly inform the creative pro fessional how these elements may be distorted by the utilized output device. Knowledge gained by the creative professional in regards to these effects helps to answer many questions regarding print or proof quality and proper output device application. Finally, additional knowledge gained by designers which pertains to proper viewing of all color output, color theories, color measurement, and proofing sub strates helps them to better communicate with those prepress and print professionals involved in the production process

    Printing research

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    Issued as Interim technical report and final technical report Project no. A-106

    Novel patterning techniques for manufacturing organic and nanostructured electronics

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2007.Page 206 blank.Includes bibliographical references.Molecular organic semiconductors and nanometer size particles are two new classes of functional materials allowing fabrication of electronic devices on low-cost and large area substrates. Patterning these electronic materials requires the development of unconventional techniques, and the scientific understanding behind the manufacture processes. We introduce the first-generation Molecular Jet (MoJet) printing technique for vacuum deposition of evaporated thin films and apply it to the fabrication of high-resolution pixelated (800 ppi) molecular organic light emitting devices (OLEDs) based on aluminum tris(8-hydroxyquinoline) (Alq3), and the fabrication of pentacene based organic field effect transistors (OFETs) with narrow channel (15 gm) and asymmetric silver/gold contacts. Patterned printing of both organic and metal films is demonstrated, with the operating properties of MoJet-printed OLEDs and OFETs shown to be comparable with the performance of devices fabricated by conventional evaporative deposition through a metal stencil. This MoJet printing technique is reconfigurable for digital fabrication of arbitrary patterns with multiple material sets and a high print accuracy of better than 5gtm, and scalable to large area substrates.(cont.) Analogous to the concept of "drop-on-demand" in Inkjet printing technology, MoJet printing is a "flux-on-demand" process and we show it capable of fabricating multi-layer stacked film structures, as needed for engineered organic devices. We present the concept and the applications of the second-generation MoJet printing technique. Using this technique, we demonstrate patterned molecular organic semiconducting thin films directly printed by a three-step local evaporative deposition, in conjunction with using the HP thermal InkJet printing technology. This MoJet printing technique can be applied to pattern solution-processable molecular organic thin films, providing flux-on-demand in an ambient environment. We develop an Inkjet assisted micro-contact printing technique for the patterning of colloidal semiconductor nanoparticles. Active OLEDs incorporated with a uniform thickness layer of colloidal nanoparticles are fabricated by using this Inkjet printing plus stamp transferring technique. The material usage efficiency is largely boosted. To our knowledge, these three novel patterning techniques presented in this study provide for the first time unprecedented capabilities for manufacturing organic and nanostructured electronic devices.by Jianglong Chen.Ph.D

    Controlled spatial arrangement of gold nanoparticles using focused laser beams and DNA origami

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    Organic Semiconductor Lasers and Tailored Nanostructures for Raman Spectroscopy

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    This work presents the application of organic semiconductor distributed feedback laser as free-space excitation source in Raman spectroscopy. Surface-enhanced Raman scattering effect is exploited to improve the detection sensitivity. The SERS conditionis achiedved by using substrates consisting of gold-coated polymeric nanopillar arrays. The organic-laser-excited SERS measurements are applied to verify the concentration variation of biomolecule adenosine in aqueous solutions

    Responsive liquid crystal networks

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    Responsieve polymeren zijn interessant voor een groot aantal toepassingen, omdat de eigenschappen van deze materialen over een breed bereik ingesteld kunnen worden en het bovendien mogelijk is om ze tegen lage kosten en op grote schaal te fabriceren. Vloeibaar-kristallijne netwerken vormen een platformtechnologie voor deze responsieve materialen. Een groot aantal stimulusgevoelige moleculen kunnen worden toegevoegd om het polymeer gevoelig te maken voor warmte, licht, pH, waterdamp of biologische stimuli. De vloeibaar-kristallijne kernen van het polymere netwerk versterken de stimulus, wat snelle en grote responsies tot gevolg heeft. De responsies kunnen zowel mechanische als optische veranderingen zijn, en zijn naar wens reversibel of irreversibel te maken. In dit werk wordt het gebruik van deze materialen in microsystemen, zoals lab-on-a-chip, onderzocht. Actuatie met licht wordt gekozen omdat dit compatibel is met een natte omgeving en van afstand aangestuurd kan worden.Theoretische en experimentele resultaten laten zien dat door een optimalisatie van de moleculaire ordening in een ‘splaybend’ orientatie, de prestaties van buigende actuatoren sterk verbeterd kan worden. Daarnaast is er theorie ontwikkeld die de beweging van de actuator onder invloed van aansturing met licht beschrijft en deze theorie wordt door experimentele resultaten bevestigd. Voor toepassing in microfluidische systemen worden actuatoren ontworpen die gebaseerd zijn op cilia in natuurlijke organismen. Deze actuatoren kunnen dienen als pompen en mixers, maar daarvoor is het noodzakelijk dat de beweging van de cilia asymmetrisch in de tijd is. Verschillende manieren voor het genereren van deze asymmetrische beweging zijn onderzocht. Eén manier maakt gebruik van actuatoren bestaande uit verschillende delen die elk reageren op een andere kleur licht. Een andere manier maakt gebruik van een gradient in compositie van de actuator door de dikte van het materiaal, waardoor een sterk niet-lineaire responsie ontstaat. Verschillende methodes voor het miniaturiseren van deze actuatoren zijn verkend, waaronder lithografie en inkjet printen. Het is aangetoond dat met inkjet printen, actuatoren kleiner dan een millimeter gemaakt kunnen worden, zonder dat de prestaties van de actuatoren daaronder te leiden heeft. Behalve de toepassing van vloeibaar-kristallijne netwerken als actuatoren is de toepassing als sensor ook onderzocht. Als het materiaal een cholesterische ordening heeft, kan dit een gedeelte van het licht reflecteren. Als de reflectieband in het zichtbare gedeelte van het licht ligt, lijkt het materiaal een kleur te hebben. Net als bij de actuatoren kan het netwerk gedeformeerd worden door de moleculaire ordening te verstoren of door het te laten zwellen of krimpen, hetgeen een zichtbare verschuiving van de reflectieband tot gevolg kan hebben. Het is aangetoond dat door gebruik te maken van waterstofbruggen in het netwerk, cholesterische sensoren kunnen reageren op vluchtige amines, pH of temperatuur. Als alternatief voor de licht gestuurde actuatoren zijn magnetisch gedreven, ferromagnetische systemen onderzocht. Magnetische velden zijn net als licht compatibel met een nat milieu en kunnen van afstand aansturen. Twee methodes zijn onderzocht om kunstmatige magnetische cilia te maken: ‘glancing angle’ depositie van nikkel op PDMS scharnieren en electrolytisch gegroeid nikkel in een membraan. De beste resultaten werden bereikt met electrolytische gegroeide staafjes die vrij in een kanaal ronddreven. Toepassingen van de actuatoren uit dit onderzoek liggen in medische applicaties zoals lab-on-a-chip systemen, maar ook in andere toepassingen zoals mechatronica en textiel. Omdat de materialen in een continu proces aan de lopende band verwerkt kunnen worden, hebben ze de potentie om in goedkope systemen zoals slimme verpakkingen of wegwerp applicaties toegepast te worden

    Role of Hybrid Operating Room: Present and Future

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    With the dramatic progress of medical imaging modalities and growing needs for high-resolution intraoperative imaging in minimally invasive surgery, hybrid operative room (OR) has been developed as a powerful tool for different surgical scenarios. Under the guidance of high-definition cone beam CT (CBCT), an electromagnetic navigation bronchoscopy (ENB)-based marker implantation and subsequent localization of the pulmonary nodules can be implemented within a hybrid OR. Furthermore, the unparalleled real-time imaging capabilities and the ability to perform multiple tasks within the hybrid OR can facilitate image-guided single-port video-assisted thoracic surgery (iSPVATS), increasing the precision and improving outcomes of the procedure. With the help of a hybrid theatre, catheter-based thermal ablation can provide a safer and less invasive treatment option for select patient groups with early-stage non-small cell lung carcinomas (NSCLC) or metastases. In the future, the combination of hybrid operating room and other inspiring innovative techniques, such as robotic bronchoscopy, 3D-printing, natural orifice transluminal endoscopic surgery (NOTES) lung surgery could lead to a paradigm shift in the way thoracic surgery is conducted

    Liquid-Crystal-Elastomer Laser-Microprinted 3D Optomechanical Metamaterials

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    Effective application of digital printing techniques for fine artists in the South African context

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    The question to be answered by this research is how would a fine artist working in South Africa, identify and use the correct digital printing techniques to accurately print their work
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