bluuebunny/crossref_metadata_2025 huggingface dataset:
The status of Ghanaian community health workers’ supervision and service delivery: descriptive analyses from the 2017 Performance Monitoring and Accountability 2020 survey
Authors: Schwarz Dan , Kim June-Ho , Ratcliffe Hannah , Bell Griffith , Awoonor-Williams John Koku , Nimako Belinda , Otupiri Easmon , Lipsitz Stuart , Hirschhorn Lisa , Bitton Asaf
Published: June 2019

Introduction: Community-based services are a critical component of high-quality primary healthcare. Ghana formally launched the National Community Health Worker (CHW) program in 2014, to augment the pre-existing Community-based Health Planning and Services (CHPS). To date, however, there is scant data about the program’s implementation. We describe the current supervision and service delivery status of CHWs throughout the country.

Methods: Data were collected regarding CHW supervision and service delivery during the 2017 round of the Performance Monitoring and Accountability 2020 survey. Descriptive analyses were performed by facility type, supervisor type, service delivery type, and regional distribution.

Results: Over 80% of CHWs had at least monthly supervision interactions, but there was variability in the frequency of interactions. Frequency of supervision interactions did not vary by facility or supervisor type. The types of services delivered by CHWs varied greatly by facility type and region. Community mobilization, health education, and outreach for loss-to-follow-up were delivered by over three quarters of CHWs, while mental health counseling and postnatal care are provided by fewer than one third of CHWs. The Western region and Greater Accra had especially low rates of CHW service provision. Non-communicable disease treatment, which is not included in the national guidelines, was reportedly provided by some CHWs in nine out of ten regions.

Conclusions: Overall, this study demonstrates variability in supervision frequency and CHW activities. A high proportion of CHWs already meet the expected frequency of supervision. Meanwhile, there are substantial differences by region of CHW service provision, which requires further research, particularly on novel CHW services such as non-communicable disease treatment. While there are important limitations to these data, these findings can be instructive for Ghanaian policymakers and implementers to target improvement initiatives for community-based services.
Data: storage and processing
Authors: Дадян Эдуард , Dadyan Eduard
Published: June 2019

The textbook examines and analyzes: databases and DBMS, data and computers, database concept, DBMS architecture, infological, datological and physical data models, date types of logical data models, data presentation using the model " Entity-Relationship, Entity-Relationship diagram, data integrity. An overview of the notation used to build the entity-link diagrams is given. In detail: relational databases, operations with relational database tables, relational relationship generation rules from entity to link model. The following sections are presented in detail: fast data access tools, SQL language, physical database organization, client-server architecture, distributed data processing and database server structure. The textbook also formulates conceptual bases of the concept "knowledge", sets out concepts and definitions of knowledge, knowledge bases, models of representation of knowledge. Here are the principles of building systems for data analysis-data warehousing, data models used in building data warehouses. The tutorial ends with the consideration of data protection issues.
Trabalho e reconhecimento entre técnica, política e afetividade
Authors: Souza Carolina Rodrigues Alves de , Carrete Teresa Cristina Othenio Cordeiro
Published: June 2019

Este artigo analisa o reconhecimento no trabalho. Trata-se de recorte de tese de doutorado em andamento que tem como campo os Centros de Referência Especializados da Assistência Social (CREAS) de Aracaju-SE, Brasil. Utilizando a psicossociologia como aporte teórico e metodológico, realizamos oficinas grupais com educadores sociais, psicólogos e assistentes sociais de três CREAS daquele município. A psicossociologia está atenta aos conflitos que surgem no contexto institucional e organizacional e às diversas modalidades de mal-estar que ali se instauram, favorecendo o olhar sócio-clínico e a intervenção. Neste texto, discutiremos o trabalho no campo em questão atentando para sua função social e pensando-o enquanto via de acesso ou não ao reconhecimento social dos seus trabalhadores.
Habilidades sociais e prevenção do suicídio: Relato de experiência em contextos educativos
Authors: Leme Vanessa Barbosa Romera , Chagas Adriana Pinheiro Serqueira das , Penna-de-Carvalho Aline , Padilha Amanda Porto , Alves Ana Júlia De Carvalho Pereira , Rocha Carolina Seixas da , França Fernanda De Azevedo , Jesus Fernanda Dos Santos Quintanilha de , Calabar Fernanda Pereira , Mattos Lana Pereira , Leopoldino Letícia Costa , Fernandes Luana De Mendonça , Silveira Priscila Sá da
Published: June 2019

Este estudo tem por objetivo apresentar um relato de experiência de um projeto que realizou oficinas e palestras sobre habilidades sociais e de vida em diferentes contextos educativos. As ações extensionistas são desenvolvidas com estudantes, docentes e funcionários técnicos-administrativos de uma universidade pública e alunos, professores e demais funcionários de escolas públicas da educação básica, localizadas no Estado do Rio de Janeiro. São apresentadas quatro oficinas e uma palestra realizadas na universidade e nas escolas. Todas as ações foram baseadas na promoção das habilidades sociais e de vida e evidenciaram, por meio dos relatos dos participantes, alguns ganhos no autoconhecimento e satisfação com atividades propostas. Ao final são analisados o impacto das atividades e os desafios que envolveram o projeto com foco na promoção de saúde mental e prevenção do suicídio.
Theorising the EU in crisis: de-Europeanisation as disintegration
Authors: Rosamond Ben
Published: June 2019

The current 'perfect storm' of European crises seems to provide evidence that the EU is suffering from severe tensions that could reverse many of the key integration gains of the past seven decades. The presence of apparently existential threats to the EU has provoked calls to theorise
'disintegration'. This presumes, first and foremost, that scholarship is lagging behind urgent real world developments. It could also be argued that any attempt to theorise integration should by definition be capable of theorising disintegration. EU studies scholarship has tended, in
recent years, to shy away from the analysis of integration, developing instead a range of subliteratures that together presume institutional and systemic resilience. The paper makes three broad arguments. First, it notes that any return to the analysis of integration/disintegration presents
a risk for scholarship, namely the fallacy of sampling from past experience to project future probabilities. Second, it demonstrates that earlier neofunctionalist scholarship had, in fact, developed quite sophisticated accounts of disintegration, which, in turn illustrated the importance of
understanding the key role played by political economy and sociological dynamics in European integration. Finally, the paper explores the ways in which extant scholarly knowledge about the EU may inhibit the development of robust policy understanding of potentially disintegrative dynamics.
‘Cry God for Harry, England, and Saint George’: Europe and the limits of integrating identity
Authors: Foster Russell
Published: June 2019

Since the early 1990s a dominant modernist narrative has assumed that European integration and the progressive march of secularism, multiculturalism and increased material prosperity would lead to the fading-away of tribal, national, racial and other parochial identities; identities ostensibly incompatible with a meta-national ‘European’ identity founded not in ethnosymbolic myth, but in cosmopolitanism. This has informed not only academic theory but has also guided 60 years of EU policy making, with Ernst Haas’ doctrine of neofunctionalist spill-over dominating European assumptions that a pan-European identity would replace national affiliations. Brexit contradicts this in four ways. First, Brexit demonstrates the renewed appeal of ethnic nationalism on multiple levels: nationalist (British), sub-nationalist (English), and meta-nationalist (white nationalism). Second, Brexit demonstrates shifts in traditional nationalism in the form of gulfs in a neo-medieval society. Third, Brexit demonstrates the existence of multiple and incompatible ‘European’ identities. Finally, Brexit demonstrates how a specifically EUropean identity can be just as hostile and exclusionary as ethnic nationalism. This reappearance of social discord, ethnosymbolic identities, and the praxis of ethnic identity exemplified by the British, but seen across the EU, necessitates a fundamental reconsideration of the apparently irreversible trends of an unfalsifiable theory of modernist, neofunctionalist progressivism in the form of European integration. Using the British as a case study, this paper argues that the very processes of European integration have, by accelerating antagonistic national and EU identities, inadvertently constructed the apparatus for EUrope’s potential disintegration.
What does self-determination mean today? The resurgence of nationalism and European integration in question
Authors: Delanty Gerard
Published: June 2019

The paradox of nationalism today in Europe is that while there is ever more demand and opportunities for nationalism it has become more divisive than ever before. Nationalism now divides the nation rather than uniting it. For this reason, its capacity to offer an alternative to the status quo is severely limited. In the past collective self-determination was predicated on the presumption of a defined people who were resisting external domination and sought to bring about a new polity. The world today, especially in Europe, has made this more difficult, if not impossible. There is now an entirely new context for nationalism and the appeal to self-determination in the name of ‘the people’ is no longer able to achieve the same results. The politics of self-determination, as reflected in separatist movements, runs up against the problems of democracy and cultural pluralism, which tend to frustrate the capacity of nationalism to achieve its aims. The argument given in this paper is that the rise of nationalism is de-stabilising for Europeanisation but does not endanger it.
Primary Biliary Cholangitis and Primary Sclerosing Cholangitis
Authors: Yokoda Raquel T. , Carey Elizabeth J.
Published: June 2019

Cholestatic liver diseases encompass a broad spectrum of pathologies, with the core injury occurring at the level of cholangiocytes and progressing to hepatic fibrosis and liver dysfunction. Primary biliary cholangitis and primary sclerosing cholangitis are the most significant progressive cholangiopathies in adults. Although rare, they commonly evolve to liver failure and need for liver transplantation. Despite recent advances in the basic knowledge of these cholangiopathies, the pathogenesis is still elusive. Targeted treatments to prevent disease progression and to preclude malignancy are not yet available. This review will address the general clinical features of both diseases, analyze their commonalities and differences, and provide a state-of-the art overview of the currently available therapeutics.
СТУПЕНІ ПОРІВНЯННЯ ПРИКМЕТНИКІВ: ВІД ПОРУШЕННЯ НОРМИ ДО ТРАДИЦІЇ (на матеріалі словника А. Нелюби, Є. Редька Словотворчість незалежної України. 2012–2016)
Authors: Халіман Оксана
Published: June 2019

W artykule opisano tendencje tworzenia form komparatiwu i superlatiwu we współczesnym języku ukraińskim na materiale słownika A. Neluby, J. Red`ki Słowotwórstwo niepodległej Ukrainy. 2012–2016 (2017). Modele tworzenia form od przymiotników jakościowych oznaczających cechę niestopniowalną, dzierżawczych, przymiotników złożonych itp. sprzyjają reinterpretacji, rozszerzeniu struktury semantycznej słów podstawowych. Cechuje je regularność. Podkreślono potrzebę usystematyzowania odpowiednich tendencji z uwzględnieniem ich regularnej odtwarzalności w gramatyce języka ukraińskiego, ujęciem i objaśnieniem nowych odcieni semantycznych w źródłach leksykograficznych.
НАЦІОНАЛЬНО-КОНЦЕПТНИЙ ПРОСТІР У РОМАНІ ПАНАСА МИРНОГО ХІБА РЕВУТЬ ВОЛИ, ЯК ЯСЛА ПОВНІ?: ПАРАЛЕЛЬНЕ ПРОЧИТАННЯ (топос “Дім”)
Authors: Янковська Жанна
Published: June 2019

Metoda interdyscyplinarna ma dzisiaj szerokie zastosowanie w humanistyce ukraińskiej, w tym także dla odczytania dzieł literatury pięknej, co pozwala na głębszą, "nielinearną" refleksję. Niniejszy artykuł przedstawia próbę analizy powieści Panasa Myrnego Хіба ревуть воли, як ясла повні? Analiza została przeprowadzona przez pryzmat filozoficzno-kulturowego konceptu Dom — Pole — Świątynia (topos "Dom"). W praktyce badawczej koncept ten został wykorzystany po raz pierwszy przez S. Krymskiego dla przedstawienia realiów kultury narodowej.
Fatigue and Static Properties of Built-up Friction Stir Welded Ti-6Al-4V I-Beams
Authors: Sharma Rahul , Fick Damon R. , West Michael K. , Jasthi Bharat K.
Published: June 2019

Modern aircraft systems use high-strength alloys, such as Ti-6Al-4V (Ti-6-4), for their components. The advantage of using Ti-6-4 is its high corrosion resistance and low weight to strength ratio when compared with other metals. The downside of using titanium is its high cost and lead time associated with procurement in addition to the material wastage that occurs with machining different cross-sectional geometries. Built-up titanium beams fabricated using friction stir welding (FSW) and readily available titanium plates may be a viable alternative that reduces these expenses. This study investigates the fatigue and static strengths of built-up titanium I-beams using FSW and 7-mm-thick Ti-6-4 plate material and compares the results with strengths of representative coupon specimens. Coupons in the transverse and longitudinal directions of the FSW were evaluated for both polished and as-welded FSW surfaces. The results of the investigation showed that the static flexural strength of the built-up I-beam reached 57 % of the yield strength of the Ti-6-4 plate material. The fatigue strengths of the two I-beams tested reached 87 and 63 % of comparable coupon-level specimens with as-welded and polished finishes, respectively. Failures in these beams initiated at discontinuities in the welded fillet region, which suggests that strength and fatigue performance of built-up titanium I-beams can be improved through more consistent FSW methods for Ti-6-4 plate materials.
Isto não é um manual de instruções: notas sobre a construção e consumo de perfis em três redes geosociais voltadas ao público gay
Authors: Padilha Felipe
Published: June 2019

Este artigo deseja compreender a dinâmica que envolve as plataformas que criam redes sociais digitais e os seus usuários. O argumento está estruturado em três partes: inicialmente exponho o contexto de criação dos aplicativos geosociais apontando para as relações que dão plausibilidade à sua produção; em seguida, abordo como são apresentadas as propagandas desses produtos para o público potencialmente consumidor e, por fim, reflito sobre as relações implicadas na atividade de construir um perfil nessas plataformas. Pensando na dimensão arquitetural dos aplicativos, alio a etnografia em curso com homens que buscam parceiros amorosos e sexuais por meio das mídias digitais, para discutir a ressonância entre a relação desenvolvida pelos usuários, as mensagens veiculadas pela propaganda e os contextos culturais nos quais essas tecnologias são usadas.Palavras-chave: Aplicativos geossociais; Mídias digitais; Propaganda; Relações homoeróticas.
O gênero na(s) mídia(s): construções e reproduções de gênero e corpo nos meios de comunicação
Authors: Zaluski Jorge Luiz
Published: June 2019

MOREIRA, Rosemeri, CAMARGO, Hertz Wendel de, KLANOVSCZ, Luciana Rosa F. (Org.). Gênero e os Meios: Imprensa, televisão e cinema. 1ed. Londrina: Syntagma, 2014.
FORMULAÇÕES TEÓRICO- METODOLÓGICAS DE PLANEJAMENTO URBANO SOB A INSPIRAÇÃO DE HENRI LEFEBVRE
Authors: Kauffmann Marcia Oliveira , Kleiman Mauro
Published: June 2019

O forte crescimento e adensamento de construções e de população, impactantes ao meio ambiente, com consequências inclusive em inundações, muitas vezes decorrentes da impermeabilização dos solos, têm marcado os grandes centros urbanos. Discutem-se alternativas teóricas que inspiradas em Henri Lefebvre possam enfrentar estas questões e reformular o planejamento contemporâneo que, calcado em visão dualista da realidade, considera etapas estanques e excludentes na formação e desenvolvimento das cidades, deixando de observar dialeticamente as contradições e tensões entre os diversos polos de oposição presentes nesta dinâmica. A reflexão sobre os caminhos entre a cidade formal e a informal, entre a insustentável e a sustentável, em processo de constante transformação e interação, pode apontar estratégias para a superação dessa dicotomia. A adoção da bacia hidrográfica como unidade de gestão e integração entre os planejamentos urbano, ambiental e de recursos hídricos, associada ao indicador de ocupação sustentável da bacia hidrográfica (IOS-BH), conforme no presente texto, se qualificam como importantes recursos para um novo aporte teórico-metodológico em planejar as cidades. Este novo indicador, exemplificado em estudo de caso na cidade do Rio de Janeiro, em forte conexão com a matriz de planejamento, se aplica à legislação urbanística, agrega parâmetros relacionados aos recursos hídricos, urbanos e ambientais e, sobretudo, se constitui em elemento mediador entre as diversas polaridades do contexto urbano, confere retratos da sustentabilidade urbana e instrumentaliza projetos das recuperações necessárias, trazendo à luz o pensamento de Lefebvre também aplicado a novas formulações de indicadores.
La privación de libertad en el marco de los derechos humanos
Authors: Murillo Leiva William José
Published: June 2019

El presente ensayo pretende analizar las condiciones de privación de libertad en relación con los Derechos Humanos y algunos aspectos acerca de estas condiciones en donde se visualiza vulneración a estos. Así, se reflexiona sobre el espacio carcelario como un lugar que atenta contra el respeto por la vida y la dignidad humana. Finalmente, se problematiza sobre algunas de las disposiciones o consideraciones que un gobierno debe tomar en cuenta para lograr un efectivo respeto por los Derechos Humanos de las personas privadas de libertad
Prolapse of colostomy in children; characteristics, predisposing factors and preventive measures in four health facilities in Southern Nigeria
Authors: Okoro Philemon E*,Onyesoh Chinyeaka
Published: June 2019

IntroductionThe protrusion of the bowel through the stoma in a colostomy is one of thecommon complications of colostomy. Though it rarely gets secondarilycomplicated, it causes significant morbidity by virtue of the increasing bowel massoutside. The predisposing factors and progression in children are not well reportedin our region.AimTo evaluate the characteristics and occurrence of colostomy prolapse in childrenand to identify any factors predisposing to this complication in our practice.Patients and MethodsThis is a five year prospective study of paediatric colostomy in the authors’ servicebetween March 2013 and April 2018. Patients were categorized into those thatdeveloped prolapse (Pro group), and those that did not (Non Pro group). Othervariables investigated were gender, age at creation of colostomy, indication, type,and duration of colostomy, presence of raised intra abdominal pressure. Statisticswas with SPSS 21.ResultsTwenty seven (28.4%) of 95 children who had colostomy during the study perioddeveloped prolapsed. Prolapse occurred more in patients who had their colostomyat a relatively older age. There was a positive association of prolapse andHirschsprungs disease but no association with the gender or duration of stoma.ConclusionColostomy prolapse is a common complication seen in our practice. Cases ofneglected Hirschsprungs disease in children have increased risk of thiscomplication. Extra caution is therefore needed in forming colostomy in this groupof patients.
Synthesis and Electrochemical Performance of SnO2/Graphene Hybrid Anode for Lithium Ion Batteries
Authors: Lin Chia-Yi , Hsieh Chien-Te , Juang Ruey-Shin
Published: June 2019

An efficient microwave-assisted polyol (MP) approach is report to prepare SnO2/graphene hybrid as an anode material for lithium ion batteries. The key factor to this MP method is to start with uniform graphene oxide (GO) suspension, in which a large amount of surface oxygenate groups ensures homogeneous distribution of the SnO2 nanoparticles onto the GO sheets under the microwave irradiation. The period for the microwave heating only takes 10 min. The obtained SnO2/graphene hybrid anode possesses a reversible capacity of 967 mAh g-1 at 0.1 C and a high Coulombic efficiency of 80.5% at the first cycle. The cycling performance and the rate capability of the hybrid anode are enhanced in comparison with that of the bare graphene anode. This improvement of electrochemical performance can be attributed to the formation of a 3-dimensional framework. Accordingly, this study provides an economical MP route for the fabrication of SnO2/graphene hybrid as an anode material for high-performance Li-ion batteries.
Materials Engineering with a Social Context: A course on Materials, Ethics, & Society
Authors: Chen Katherine C.
Published: June 2019

A sophomore level Materials Engineering course entitled, “Materials, Ethics, & Society” at Cal Poly analyzes the interactions between technology and society, and emphasizes the communication of societal and ethical impacts of technology to diverse audiences. Students study materials in a historical context, not only to highlight specific materials science concepts, but also to explore societal-technology connections. Starting from the Stone Age, advances in civilizations have come about through discoveries and new uses of materials. World geography, history, and culture become intertwined with the casting of metals, alloy development, ceramics, and phase diagrams. Students highlight the social relevancy of materials throughout history, and seek parallel themes in today’s world. While learning about the development of the atomic bomb, students also examine the ethical dilemmas of the scientists and the current NSPE Code of Ethics for Engineers. In addition, the role of the engineering profession is examined with the NAE Engineering Grand Challenges and current news items. Students investigate how materials engineering can help society through examples of appropriate technology solutions, such as designing porosity in ceramics for water filters and food storage pots. Students develop their analytical and communication skills by discussing C.P. Snow’s “two cultures” and debating a rationale for scientific literacy. Students are also trained in informal science learning in preparation for NanoDays with young and diverse audiences. At the same time, they learn about nano-scale science and technology principles, and the associated societal and ethical implications. The course culminates with student-created videos for the general public that highlight a material or technology of importance to society and integrates the material science with ethical, environmental, and societal dimensions.
Math and Science Education Module for Introducing Nanotechnology, Light and Energy for Middle School Classrooms
Authors: Boykin Karen , Pan Shanlin , Goldston Dee , Allison Elizabeth
Published: June 2019

The introduction of nanotechnology in early classroom pedagogy is becoming a high priority in education. However, the concepts of nanotechnology can be difficult to conceptualize due to the esoteric nature of the subject. Inquiry-based nanotechnology modules are one way to help visualize nanomaterials to deliver the concepts of nanotechnology. We present the implementation and effectiveness of a newly developed module tying existing light and energy curriculum in middle school to nanoparticles, introducing the concept of a photocatalyst and energy. The module is part of a five year teacher professional development program in the Alabama Black Belt through a Math Science Partnership award from NSF (0832129) to increase students’ interests at the middle school level for pursuing continued math and science education and creative research activities in the future. Students impacted by the program are from low income rural communities where it is critical in preparing the next generation scientists and engineers for our nation’s future energy challenges.
Plasmonic Light Trapping in Amorphous Si Solar Cells Using Periodic Ag Nanodisk Structures
Authors: Mizuno Hidenori , Sai Hitoshi , Matsubara Koji , Kondo Michio
Published: June 2019

This paper describes light trapping in superstrate-type amorphous Si solar cells incorporated with Ag nanostructures (nanodisks) fabricated by a transfer-printing approach. The changes in external quantum efficiency (EQE) and current-voltage characteristics were investigated by changing the position and size (thickness) of the Ag nanodisks in the cells fabricated on flat superstrates. It was confirmed that the optimized Ag nanodisk-configuration led to the enhanced EQE (20%) in the 600-800 nm wavelength range, and the enhanced EQE led to the improved overall conversion efficiency (7.5%) compared to the cell without Ag nanodisks (7.2%). However, the integration of the optimized Ag nanodisk-configuration with the cells fabricated on textured superstrates did not result in the enhanced EQE and conversion efficiency, suggesting further optical designs are necessary to exploit both texture- and plasmon-mediated light trapping effects.
Investigating the surface changes of silicon in vitro within physiological environments for neurological application
Authors: Nezafati Maysam , Saddow Stephen E. , Frewin Christopher L.
Published: June 2019

Silicon has been used as one of the primary substrates for micro-machined intra-cortical neural implants (INI). The presence of various ions in the extracellular environment combined with cellular biological activity establishes a harsh, corrosive environment in the brain for INI, and as such, a long-term implant’s construction materials must be able to resist these environments. We have examined if environmental components could contribute to changes in the material, which in turn may be a contributing factor to the decreased long-term reliability in INI optimal neural recordings, which have prevented clinical use these devices for the last 4 decades. We tested silicon in artificial cerebrospinal fluid (ACSF), Dulbecco's modified eagle medium (DMEM), and H4 cells cultured within DMEM for 96 hours at 37°C as three various physiological environments to investigate the material degradation. We have observed that Si samples immersed in only DMEM and ACSF showed very minor surface alterations. However, Si samples cultured with H4 cells exhibited a large change in surface roughness from 0.24±0.04 nm to 4.85 nm. The scanning electron microscope (SEM) micrographs showed the presence of pyramid shaped pits. Further characterization with atomic force microscope (AFM) verified this result and quantified the severe changes in the surface roughness of these samples. At this initial stage of the investigation, we are endeavoring to identify the cause of these changes to the Si surface, but based on our observations, we believe that the increased corrosion could be result of chemical products released into the surrounding environment by the cells.
Effect of Microstructure on Phase Formation in Reaction of The Nb/Al Multilayer Thin Films
Authors: Barmak Katayun , Coffey Kevin R. , Rudman David A. , Foner Simon
Published: June 2019

We investigated the phase formation sequence in the reaction of multilayer thin films of Nb/Al with overall compositions of 25 and 33 at.% AI. We report novel phenomena which distinguish thin-film reactions unequivocally from those in bulk systems. For sufficiently thin layers composition and stability of product phases are found to deviate significantly from that predicted from the equilibrium phase diagram. We demonstrate that in the Nb/Al system the length scales below which such deviations occur is about 150 nm. We believe that these phenomena occur due to the importance of grain boundary diffusion and hence microstructure in these thin films.
Phase Transformations in Co/Nb and Co/Zr Multilayer Film Stacks.
Authors: Lin J. C. , Hoffman R. A.
Published: June 2019

Ion-beam mixing and isothermal annealing techniques were applied to induce phase transformations in Co/Nb and Co/Zr multilayer film stacks. Transmission electron microscopy(TEM) and x-ray diffraction(XRD) were used to characterize the microstructure of the films. Interfacial morphology and chemistry of the films were examined by Rutherford backscattering spectrometry(RBS) and cross-section transmission electron microscopy(XTEM). The formation of amorphous phases was found in both systems by either technique. A comparison of the phase transformation mechanisms induced by ion-beam mixing and isothermal annealing is given. The thermodynamic and kinetic factors controlling the phase formation and stability are discussed. For the isothermal annealing, the final stable configuration is predicted by equilibrium phase diagrams.
Changes in u(VI) SPeciation Upon Sorption onto Montmorillonite from Aqueous and Organic Solutions
Authors: Chisholm-Brause Catherine , Conradson Steven D. , Eller P. Gary , Morris David E.
Published: June 2019

The speciation of UO22+ and UO22+/ TBP mixtures has been investigated in solution and intercalated with the reference smectite clay SAz-1 using x-ray absorption, Raman, andluminescence spectroscopies. Neither aquated UO22+ nor its TBP complex undergoes any detectable changes in uranium oxidation state on intercalation. Further, at the pH values employed in this work, there is no evidence for hydrolysis of the uranium species to generate dimeric or higher order uranium oligomers. However, we do find indications that the structures of the solution complexes are altered on intercalation, particularly for the UO22+TBP system and for more dilute UO22+/aqueous systems. In addition, several lines of evidence suggest that, at the loading levels used in this study, the uranyl species is interacting with two or more spectroscopically distinguishable sites on SAz-1.
Integrated, Dual-Function Remote Plasma-Enhanced Processing Applied to Low Damage SiO2 Etching and Removal of C-F Polymer Residues
Authors: Yasuda T. , Lucovsky G.
Published: June 2019

We report a dual-function chamber integrating (a) remote RF plasma-enhanced etching of SiO2 layers on Si(100) surfaces with low energy, <100 eV, ion bombardment and (b) in-situ removal of polymeric C-F residues that are formed on the exposed Si surfaces. Using direct plasma excitation of He and downstream introduction of CF4, an SiO2 etch rate of ̃5 nm/min was obtained at a CF4 partial pressure as low as 0.25 mTorr. An exposure to atomic-H at a substrate temperature of 250°C was effective in removing polymeric residues from the Si surface, while an exposure to reactive O-species was less effective. We achieved a low-temperature, ̃300°C, homoepitaxial growth of Si on the Si(100) surface that was subjected to plasma etching followed by an exposure to atomic-H. The electrical damage of the processed Si surfaces was evaluated by a new technique, where a device-quality SiO2 film was deposited on this surface by remote PECVD and the C-V characteristics of the MOS structure were measured.
Bulk Restructuring of Amorphous Tungsten Trioxide Films Due to Hydration of the Film/Electrolyte Interface
Authors: Shiyanovskaya I. V.
Published: June 2019

The influence of film/electrolyte interface on structure and electrochromic properties of amorphous WO3 (a-WO3) films has been studied using cyclic voltammetry, optical electrochemistry and vibrational spectroscopy.
Electrochemical Fabrication of the Nano-Wire Arrays: Template, Materials And Applications
Authors: Routkevitch Dmitri , Chan Jimmy , Davydov Dmitri , Avrutsky Ivan , Xu J. M. , Yacaman M. J. , Moskovits Martin
Published: June 2019

Anodic aluminum oxide (AAO) may be used as a template for electrochemically fabricating metal and semiconductor nano-wires. We assess the seminal factors involved in each step in this fabrication process with an aim at producing device-quality semiconductor nano-arrays. This includes an analysis of the electrochemical factors, the structural effects resulting from the templating, the crystallinity of the nano-wires, their anisotropy and their suitability for device applications.
Photonic Applications of Bipolaron Formation in Bis-(Diphenylamino)Diphenylpolyene
Authors: Ashworth K. , Reeves B. , Frost A. , Spangler C.
Published: June 2019

Bis-(dialkylamino) and bis-(diphenylamino) substituted diphenylpolyenes have recently been shown to have exceptionally large two-photon cross-sections, and have also been used in optical power limiting (OPL) applications. Another potential mechanism for OPL in these materials involves the photogeneration of highly absorbing polaronic radical-cations or bipolaronic dications which can then function as highly absorbing reverse saturable absorbers (RSAs). The synthesis of series of these unique polyenes has been carried out, as well as studies of chemically induced bipolaron formation in solution. In order to actually be used in OPL devices, it is probable that these chromophores will need to be incorporated into polymer formulations, In this paper we describe three distinct ways that these chromophores can be incorporated in polymer structures: (1) as pendant groups attached to a PMMA backbone, (2) as formal repeat units in a copolymer, and (3) perhaps the most interesting, as surface attached functionalities in dendrimer formulations. The formation of bipolaron charge species in these polymers will be addressed.
Humidity-Induced Cohesion Effects in Granular Media
Authors: Fraysse Nathalie , Petit Luc
Published: June 2019

Experiments were performed under accurately-controlled humidity conditions in order to quantify effects induced by humidity on granular materials. Measurements of the maximal stability angle of a pile made of small glass beads are reported as a function of the relative vapor pressure in the cell, up to close to saturation. The comparison of the results obtained with fluids differing in their molecular interactions with glass, namely water and heptane, shows that the wetting properties of the interstitial liquid on the grains have a strong influence on the cohesion of the non-saturated granular medium. This suggests that gravimetric experiments which could indirectly give information on the size of the capillary bridges that form between grains should be useful to understand the close connection that exists, through interparticle forces, between microscopic properties such as wetting properties and surface roughness of the grains, and global-scale properties of the pile, as its stability and flowability.
Subsurface Damage Characterization of Hydrogen Ion Implanted Silicon Wafer with Uv/Millimeter-Wave Technique
Authors: Ogita Yoh-Ichiro , Kobayashi Ken-Ichi , Kurokawa Masaki , Kondo Hideyuki , Katoh Takeo
Published: June 2019

The UV/mm-wave technique composed of ultraviolet photoexcitation and millimeter wave probe was examined with photoconductivity amplitude (PCA) to characterize the slight subsurface damage induced by implanting H2+ ion into the subsurface at sub micron depth of Si wafers. The identical samples were also characterized using pulse photoconductivity amplitude (PPCA) obtained by another technique which is specified by blue laser photoexcitation and microwave probe. PCA decreased with increase of ion dose, which coincided well with the result in PPCA. PPCA decreased with increase of implantation energy as 90 to 120 keV, but PCA increased at 120keV. Both PCA and PPCA well reflected the damage at sub micron depth. PCA reflected damage in shallower depth compared to PPCA.
Atomically-based Field Formulations for Coupled Problems of Composition and Mechanics
Authors: Garikipati Krishna , Bassman Lori C.
Published: June 2019

Preliminary ideas are presented on developing coupled, continuum field formulations for composition and mechanics with applications to microelectronic materials. A thermodynamic basis is constructed, reflecting atomic-level transport mechanisms and the associated mechanics. Formal arguments lead to constitutive field relations, and specification of balance laws completes the coupled field description. Early numerical results are also presented.
Recent developments in sensitized mesoporous heterojunction solar cells
Authors: Krüger Jessica , Bach Udo , Plass Robert , Piccerelli Marco , Cevey Le , Grätzel Michael
Published: June 2019

The performance of solid-state dye-sensitized solar cells based on spiro-MeOTAD (2,2'7,7'-tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9'-spirobifluorene) was considerably improved by decreasing charge recombination across the interface of the heterojunction. This was achieved by blending the hole conductor matrix with a combination of 4-tert-butylpyridine (tBP) and Li[CF3SO2]2N. Open circuit voltages (Uoc) over 900mV and short circuit currents (Isc) up to 5.1 mA were obtained, yielding an overall efficiency of 2.56 % at AM1.5 illumination. Further improvement of the device performance was observed when conducting stripes of silver were deposited onto the devices as charge collector. The beneficial effect however could be assigned to the contamination of the dye-sensitized TiO2 film with silver during the dyeing process.
Ab Initio Studies On Phase Behavior of Barium Titanate
Authors: Uludogan Mustafa , Cagin Tahir , Goddard William A.
Published: June 2019

Using DFT methods we have studied structure, equation of state, and phase behavior of BaTiO3. We have identified the pressure induced phase transformations from the rhombohedral to orthorhombic structure at ca. 5 GPa and from tetragonal phase to cubic phase at ca. 7.5 GPa.
Optimization of Thermal Processing and Chemistry in the Fabrication of a PZT Based Mems Power Generator
Authors: Olson B.W. , Skinner J.L. , Richards C.D. , Richards R.F. , Bahr D.F.
Published: June 2019

Thin films of lead zirconate titanate (PZT) are currently being used in a novel MEMS device to generate power. A piezoelectric stack consisting of platinum/PZT/gold is deposited by sputtering, spin coating, and subsequent heat treatments onto a thin silicon membrane, which is cyclically polarized by a flexing motion. The membrane must withstand strains between 0.1% and 0.5% for several billion cycles to provide a useful device. This study has examined the processing-structure-property relationships in developing the PZT film for use in this device. In the sol-gel deposition of PZT, pyrolysis and crystallization temperatures have been shown to alter both microstructure and properties of the piezoelectric film. The chemistry of the PZT film has also been tailored to increase piezoelectric output for this device. Ferroelectric properties are compared to the piezoelectric outputs, and fatigue behavior is measured on bulk silicon and on membranes.
The Orthorhombic Phase of CaSiO3 Perovskite
Authors: Magyari-Köpe Blanka , Vitos Levente , Grimvall Göran , Johansson Börje , Kollár János
Published: June 2019

Ab initio total energy calculations, combined with the global parametrization method of perovskite structures, are used to investigate the stability of cubic CaSiO3 against octahedral rotations. We propose an equilibrium crystal structure of orthorhombic Pbnm symmetry. The larger compressibility of the SiO6 octahedra relative to the CaO12 polyhedra is reflected in gradual reduction of the orthorhombic distortion with hydrostatic pressure.
Suppression of the Relaxor State in Ca-Doped SrTiO3 with Modest Pressure
Authors: Venturini Eugene L. , Samara George A. , Kleemann Wolfgang
Published: June 2019

We report very large changes under modest hydrostatic pressure in the nature of the relaxor ferroelectric (FE) response for a single crystal of SrTiO3 doped with 0.7 mol % CaTiO3. The Ca cation dopants generate polar clusters within the FE soft mode, readily polarized host crystal. At ambient pressure the cluster size increases with decreasing temperature, leading to a dispersive (relaxor) state below ∼18 K. However, the application of modest pressure stiffens the soft mode frequency of the host lattice and reduces cluster growth, thereby decreasing the glass-like transition temperature at roughly –35 K/kbar. Above 0.5 kbar there is no evidence for the relaxor state; rather, a temperature- and frequency-independent dielectric response reflecting quantum paraelectric behavior evolves. These results demonstrate the extreme sensitivity to pressure of relaxors with low transition temperatures, i.e., in the quantum regime where characteristic energies are small.
Roughness of electronic interfaces in Ga As p-n multilayers investigated by cross-sectional scanning tunneling microscopy
Authors: Jäger N. D. , Urban K. , Weber E. R. , Ebert Ph.
Published: June 2019

We investigated the roughness of the electronic interfaces of GaAs p-n multilayers using cross-sectional scanning tunneling microscopy. We demonstrate that these interfaces exhibit a much larger roughness than the underlying essentially perfect ‘metallurgical’ interface, due to the individual long range electrostatic screening fields around each dopant atom near the interface and due to a clustering of dopant atoms. The clustering and the inherently connected local lack of dopant atoms gives rise to charge carrier depletion zones extending locally through entire nominally homogeneously doped layers once the layer thickness is close to the cluster dimensions. Thus, local variations in the dopant atom distribution limit the precision of the spatial and energetic positioning of the Fermi energy in nanoscale semiconductor structures.
Characterization of SiC Implanted with B or Al Using Thermal Admittance Spectroscopy
Authors: Smith S.R. , Capano M.A. , Evwaraye A.O.
Published: June 2019

We have measured the thermal activation energies of electrically active defects in 4H- and 6H-SiC implanted with either Al or B ions, using Thermal Admittance Spectroscopy. The net acceptor concentrations were monitored using room temperature low frequency Capacitance-Voltage measurements. The substrates were n/n+ epilayers. The implantations plus annealing produced p-type layers that were acceptable for characterization. The specimens were annealed in Ar at 1600 ° C, after which Ni Schottky diodes were fabricated on the specimens. Annealing times were 5, 15, 30, and 60 min. In some of the specimens, a shallow level was found that did not correspond to known levels. As the annealing progressed, energy shifts were noted for some of the detected levels. In some specimens, the implanted p-type impurity and the n-type residual dopants in the substrate were simultaneously detected. Measurements of electrically active ptype species were compared to “control” specimens implanted with Ar. From this comparison, we conclude that at least one shallow donor level is introduced into the bandgap by the implantation process, and is not annealed out. The defects associated with the implantation may affect actual device performance of diodes by destabilizing the lattice occupation of the implanted dopant atoms (energy shift with annealing), and act as lifetime killers.
Influences of Lattice Sinks and Defect Interactions on Solutes in Compounds
Authors: Collins Gary S. , Zacate Matthew O.
Published: June 2019

A thermodynamic model for the site preference of dilute solutes in ordered compounds was developed recently. The model is extended here in two ways to help interpret experimental results from this laboratory. (1) A preference for solutes to occupy sites in ‘sinks’ such as grain boundaries rather than regular lattice sites is included using a simple model. A wide range of site preference behavior is found; for example, a solute may switch between substitutional and sink sites with changing composition. (2) The effect of an attractive interaction between solute and defect on the site preference is examined. Conditions are established under which a solute can be stabilized by association with a defect on a site where the solute would otherwise not be found.
Photo-induced Dissociation and Optical Cross Section of Si-H and S-H Complexes in GaAs and AlGaAs
Authors: Barbé M. , Bailly F. , Chevallier J. , Silvestre S. , Loridant-Bernard D. , Kurowski L. , Constant E. , Constant M.
Published: June 2019

In GaAs, (Si,H) complexes are efficiently dissociated at 300 K by photons with energies above 3.5 eV. Their optical cross-section is 10-19-10-18 cm2. This dissociation is the result of an electronic excitation of the Si-H bond of the complex from a bonding state to an antibonding state. (Si,H) and (S,H) complexes in AlGaAs alloys are also dissociated under UV illumination with optical cross-sections similar to GaAs. In passivated 2D AlGaAs-GaAs heterostructures, the evolution of the extra sheet carrier concentration at low photon densities presents a loss of free carriers attributed to the filling of surface states. In AlGaAs and in 2D AlGaAs-GaAs heterostructures, the replacement of hydrogen by deuterium in the complexes shows that the (Si,D) and (S,D) complexes are significantly more stable than the (Si,H) and (S,H) complexes as previously found in GaAs:Si,H.
Photoluminescence and Infrared Absorption Study of Isoelectronic Impurity Passivation by Hydrogen
Authors: Capizzi M. , Polimeni A. , Högher von Höghersthal G. Baldassarri , Bissiri M. , Bonapasta A.Amore , Jiang F. , Stavola M. , Fischer M. , Forchel A. , Sou I.K. , Ge W.K.
Published: June 2019

The effects of H irradiation and thermal annealing on the optical properties of (InGa)(AsN) heterostructures have been investigated by photoluminescence (PL) and infrared absorption, as well as by theoretical methods. It has been found that different N clusters contribute to the band gap red-shift reported for (InGa)(AsN) alloys, with a sizable localization of the carrier wavefunctions around N atoms. Infrared absorption measurements indicate that two different NH complexes are formed, whose vibrational frequencies are in good agreement with theoretical estimates. The ability of hydrogen to passivate different isoelectronic impurities is confirmed by PL results in H irradiated Zn(STe).
Field emission characteristics of carbon nanotubes synthesized by C3H4 and NH3 gases
Authors: Jeong Taewon , Han Jae Hee , Yi Whikun , Yu SeGi , Lee Jeonghee , Heo Jungna , Lee Chang Soo , Yoo Ji-Beom , Kim J. M.
Published: June 2019

Using a gas mixture of propyne (C3H4) and ammonia (NH3) as a carbon precursor, we have successfully synthesized multiwalled carbon nanotubes (CNTs) by the direct current (dc) plasma enhanced chemical vapor deposition (PECVD) onto Co-sputtered glass at 550°C. As the flow ratio of NH3 to C3H4 in the mixture gas increased, the crystallinity and alignment of CNTs were improved. In addition, the field emission characteristics of CNTs were also improved. the turn-on voltage became lower, and the current density and the field enhancement factor were more increasing. Raman spectroscopy and scanning electron microscopy were utilized to confirm the effect of the gas flow ratio on CNTs. Therefore, the gas flow ratio was found to be one of important factors to govern the crystalline and field emission characteristics of CNTs. The growth mechanism of CNTs using a C3H4 gas is under investigation with the possibility that three carbon atoms in a C3H4 molecule is converted directly to a hexagon of a CNT by combining two molecules.