Ultrathin Oxide Films by Atomic Layer Deposition on Graphene

In this paper, a method is presented to create and characterize mechanically robust, free standing, ultrathin, oxide films with controlled, nanometer-scale thickness using Atomic Layer Deposition (ALD) on graphene. Aluminum oxide films were deposited onto suspended graphene membranes using ALD. Subsequent etching of the graphene left pure aluminum oxide films only a few atoms in thickness. A pressurized blister test was used to determine that these ultrathin films have a Young's modulus of 154 \pm 13 GPa. This Young's modulus is comparable to much thicker alumina ALD films. This behavior indicates that these ultrathin two-dimensional films have excellent mechanical integrity. The films are also impermeable to standard gases suggesting they are pinhole-free. These continuous ultrathin films are expected to enable new applications in fields such as thin film coatings, membranes and flexible electronics.Comment: Nano Letters (just accepted

Songs and Writings : Oral and Literary Cultures in Early-Modern Finland

Laulut ja kirjoitukset: suullinen ja kirjallinen kulttuuri uuden ajan alun Suomessa (Songs and writings: oral and literary culture in early-modern Finland) has been written at the crossroads of historical and folkloristic studies. Our purpose is to study the interface of literary and oral cultures in early modern Finland, focusing on the sixteenth and seventeenth centuries. The book renews the understanding of exchange between the learned culture of clergymen and the culture of commoners, or “folk”. What happened when the Reformation changed the position of the vernacular language to literary and ecclesiastical, and when folk beliefs seem to have become an object for more intensive surveillance and correction? How did clergymen understand and use the versatile labels of popular belief, paganism, superstition and Catholic fermentation? Why did they choose particular song languages, poetic modes and melodies for their Lutheran hymns and literary poems, and why did they avoid oral poetics in certain contexts while accentuating it in others? How were the hagiographical traditions representing the international medieval literary or “great” tradition adapted to “small” folk traditions, and how did they persist and change after the Reformation? What happened to the cult of the Virgin Mary in local oral traditions? This book studies the relations and mutual influences of oral and literary cultures in Finland during the long period stretching from late Middle Ages to the nineteenth century. The Reformation, the process of turning vernacular languages into literary ones, the rise of new early-modern territorial principalities, and the reorganisation of the whole Baltic Sea area in the sixteenth century and after all affected both people’s everyday lives and the spheres of the sacred. The learned elites became interested in folk beliefs and practices as they started to argue about and order their own religious practices in a new way. Lutheran congregational singing spread from the German area to the northern Baltic Sea regions. The first Finnish sixteenth-century reformers admired the new Germanic models and avoided the Finnic vernacular Kalevala-metre idiom, while their successors picked up many vernacular traits, most notably alliteration, in their ecclesiastical poetry and hymns. Over the following centuries, the new features introduced via new Lutheran hymns such as accentual metres, end-rhymes and strophic structures were infusing into oral folk poetry, although this took place also via secular oral and literary routes. On the other hand, seventeenth-century scholars cultivated a new academic interest in what they understood as “ancient Finnish poetry”. The main source materials studied in this book are from the Reformation period and immediately after, when Finnish clergymen wrote their first comments and depictions of folk beliefs and worked to create Lutheran hymns in Finnish, and also largely from the nineteenth century, when most Finnish folk poetry and older oral traditions were collected. These later folklore materials are used here to shed light on the transformations of folk beliefs and poetic forms during the centuries that followed the Reformation. The emphasis is on the areas which formed the old medieval diocese of Turku (Swedish Åbo) or what the Swedish rulers called the province of Österland (Lat. Osterlandia, later Finlandia) west from the border of Nöteborg (Finnish Pähkinäsaari) between Sweden and the Grand Duchy of Novgorod in 1323. In addition, some other sources, especially from the Finnic and Scandinavian areas, are used as comparative material.Peer reviewe

Laulut ja kirjoitukset: Suullinen ja kirjallinen kulttuuri uuden ajan alun Suomessa

"Songs and writings: oral and literary cultures in early-modern Finland renews the understanding of exchange between the learned culture of clergymen and the culture of commoners, or “folk”. What happened when the Reformation changed the position of the oral vernacular language to literary and ecclesiastical, and when folk beliefs seem to have become an object for more intensive surveillance and correction? How did clergymen understand and use the versatile labels of popular belief, paganism, superstition and Catholic fermentation? Why did they choose particular song languages, poetic modes and melodies for their Lutheran hymns and literary poems, and why did they avoid oral poetics in certain contexts while accentuating it in others? How were the hagiographical traditions representing the international medieval literary or “great” tradition adapted to “small” folk traditions, and how did they persist and change after the Reformation? What happened to the cult of the Virgin Mary in local oral traditions? The first Finnish 16th-century reformers admired the new Germanic models of Lutheran congregational hymns and avoided the Finnic vernacular Kalevala-metre idiom, while their successors picked up many vernacular traits, most notably alliteration, in their ecclesiastical poetry and hymns. Over the following centuries, the new features introduced via new Lutheran hymns such as accentual metres, end-rhymes and strophic structures were infusing into oral folk poetry, although this took place also via secular oral and literary routes. On the other hand, seventeenth-century scholars cultivated a new academic interest in what they understood as “ancient Finnish poetry”. The book has an extensive English Summary for the international readership.

Programming nanostructured soft biological surfaces by atomic layer deposition

Here, we present the first successful attempt to programme the surface properties of nanostructured soft biological tissues by atomic layer deposition (ALD). The nanopatterned surface of lotus leaf was tuned by 3-125 nm TiO2 thin films. The lotus/TiO2 composites were studied by SEM-EDX, XPS, Raman, TG-DTA, XRR, water contact angle and photocatalysis measurements. While we could preserve the superhydrophobic feature of lotus, we managed to add a new property, i.e. photocatalytic activity. We also explored how surface passivation treatments and various ALD precursors affect the stability of the sensitive soft biological tissues. As we were able to gradually change the number of nanopatterns of lotus, we gained new insight into how the hollow organic nanotubes on the surface of lotus influence its superhydrophobic feature

Review Article : Atomic layer deposition of optoelectronic materials

Optoelectronic materials can source, detect, and control light wavelengths ranging from gamma and x rays to ultraviolet, visible, and infrared regions. Optoelectronic devices are usually systems that transduce electricity to optical signal or vice versa. Optoelectronic devices include many modern necessities such as lamps, displays, lasers, solar cells, and various photodetectors. Some important research topics in the field of optoelectronics materials are development of new materials, new technologies for fabricating materials, and design of device structures. Atomic layer deposition (ALD) is a technology that was developed in the early 1970s for manufacturing high-quality luminescent and dielectric films to be used in AC-driven thin film electroluminescent (TFEL) displays. Monochromic yellow-black displays based on a ZnS:Mn luminescent layer have been manufactured industrially using ALD since the mid-1980s. Multicolor displays (green-yellow-red) were successfully realized by filtering the broad emission band of ZnS:Mn or adding another luminescent material, e.g., green-emitting ZnS:Tb or SrS:Ce. However, applicable full-color AC TFEL devices could not be developed because of the lack of an efficient deep blue-emitting phosphor. Currently, the most promising application area in TFEL displays is transparent displays, which are commonly used in various vehicles. In the mid-1980s, epitaxial III-V semiconductors were studied using ALD. It was shown that manufacturing real epitaxial [atomic layer epitaxy (ALE)] films is possible for different III (Al, Ga, In) and V (N, P, As) materials. The advantages of ALE processing compared to more traditional metalorganic chemical vapor deposition or molecular beam epitaxy methods have remained low, however, and ALE is not used on a large scale. Research continues to be carried out using ALE, especially with nitride films. Thin film solar cells have continuously received attention in ALD research. ALD films may be used as both an absorber (CdTe, SnS) and a passivation [In2S3, Zn(O,S)] material. However, in the solar cell field, the real industrial-level use is in passivation of silicon cells. Thin ALD Al2O3 film effectively passivates all types of silicon cells and improves their efficiency. Transition metal dichalcogenides are emerging 2D materials that have potential uses as channel materials in field-effect transistors, as well as phototransistors and other optoelectronic devices. The problem with achieving large-scale use of these 2D materials is the lack of a scalable, low-temperature process for fabricating high-quality, large-area films. ALD is proposed as a solution for these limitations. This review covers all of these ALD applications in detail. (C) 2019 Author(s).Peer reviewe

Effect of hot calendering on physical properties and water vapor transfer resistance of bacterial cellulose films

This work investigates the effect of hot calendering on bacterial cellulose (BC) films properties, aiming the achievement of good transparency and barrier property. A comparison was made using vegetal cellulose (VC) films on a similar basis weight of around 40 g.m-2. The optical-structural, mechanical and barrier property of BC films were studied and compared with those of highly beaten VC films. The Youngs moduli and tensile index of the BC films are much higher than those obtained for VC (14.5 16.2 GPa vs 10.8 8.7 GPa and 146.7 64.8 N.m.g-1 vs 82.8 40.5 N.m.g-1), respectively. Calendering increased significantly the transparency of BC films from 53.0 % to 73.0 %. The effect of BC ozonation was also studied. Oxidation with ozone somewhat enhanced the brightness and transparency of the BC films, but at the expenses of slightly lower mechanical properties. BC films exhibited a low water vapor transfer rate, when compared to VC films and this property decreased by around 70 % following calendering, for all films tested. These results show that calendering could be used as a process to obtain films suitable for food packaging applications, where transparency, good mechanical performance and barrier properties are important. The BC films obtained herein are valuable products that could be a good alternative to the highly used plastics in this industry.The authors thank FCT (Fundação para a Ciência e Tecnologia) and FEDER (Fundo Europeu de Desenvolvimento Regional) for the financial support of the project FCT PTDC/AGR-FOR/3090/2012— FCOMP-01-0124-FEDER-027948 and the awarding of a research grant for Vera Costa

Biotransformation of lanthanum by Aspergillus niger

Lanthanum is an important rare earth element and has many applications in modern electronics and catalyst manufacturing. However, there exist several obstacles in the recovery and cycling of this element due to a low average grade in exploitable deposits and low recovery rates by energy-intensive extraction procedures. In this work, a novel method to transform and recover La has been proposed using the geoactive properties of Aspergillus niger. La-containing crystals were formed and collected after A. niger was grown on Czapek-Dox agar medium amended with LaCl 3. Energy-dispersive X-ray analysis (EDXA) showed the crystals contained C, O, and La; scanning electron microscopy revealed that the crystals were of a tabular structure with terraced surfaces. X-ray diffraction identified the mineral phase of the sample as La 2(C 2O 4) 3·10H 2O. Thermogravimetric analysis transformed the oxalate crystals into La 2O 3 with the kinetics of thermal decomposition corresponding well with theoretical calculations. Geochemical modelling further confirmed that the crystals were lanthanum decahydrate and identified optimal conditions for their precipitation. To quantify crystal production, biomass-free fungal culture supernatants were used to precipitate La. The results showed that the precipitated lanthanum decahydrate achieved optimal yields when the concentration of La was above 15 mM and that 100% La was removed from the system at 5 mM La. Our findings provide a new aspect in the biotransformation and biorecovery of rare earth elements from solution using biomass-free fungal culture systems. </p