bluuebunny/crossref_metadata_2025 huggingface dataset:
Eye tracking como estratégia educacional inclusiva: avaliação com estudantes com autismo
Authors: Cavalcante Tardelly de Araújo , Soares Jordão Frazão , Paiva Ancelmo , Maia Ivana , Benitez Priscila , Soares André
Published: December 2020

Na área de educação, profissionais ensinam e avaliam o repertório acadêmico de estudantes com as mais diversas habilidades, limitações e históricos. Alguns podem apresentar dificuldades de aprendizagem diante dos métodos convencionais de ensino, principalmente pela não adaptação aos métodos pedagógicos. Entre esses diversos estudantes, encontram-se os com Transtorno do Espectro Autista - TEA, os quais apresentam prejuízos na comunicação social e em padrões de comportamentos restritos e repetitivos. A análise do comportamento indica que atividades personalizadas, de acordo com os interesses dos estudantes, são mais eficientes no processo educacional. Este trabalho propõe usar a análise do rastreamento ocular (eye tracking) de estudantes durante a realização de atividades educacionais informatizadas, como estratégia de avaliação educacional inclusiva de estudantes com TEA. Para avaliação e demonstração dessa proposta, foram desenvolvidas atividades digitais de ensino no computador, as quais foram resolvidas por estudantes com diagnóstico de TEA. Os resultados dos experimentos evidenciam áreas das atividades que não foram olhadas pelos estudantes durante a resolução dessas atividades. Além disso, pode ser observado também se existe relação entre a movimentação do olhar e do cursor controlado pelo mouse durante a realização da atividade. Esta proposta também fornece meios para que o profissional, ao analisar o comportamento ocular do estudante, identifique se as atividades planejadas são eficientes em determinada fase do ensino. Dessa forma, a abordagem apresentada neste trabalho pode auxiliar o profissional educador na escolha de melhores metodologias de ensino, de acordo com o perfil de cada estudante.
Um Relato de Experiência da Adaptação de um Evento Acadêmico Presencial para o Contexto Virtual em Tempos de Pandemia
Authors: Rivero Luis , Salles Carlos , Bonini Tiago , Costa Sergio , Meireles Mario
Published: December 2020

A condição de isolamento provocada pela pandemia da Covid-19 mudou de forma profunda as relações humanas contemporâneas e a rotina de realização de atividades do dia a dia. No contexto de ensino, o uso de tecnologias da informação e comunicação tem apoiado o ensino a distância e a realização de atividades remotas. No entanto, a experiência da utilização deste tipo de software não tem sido muito explorada na realização de eventos acadêmicos e científicos. Este tipo de eventos, que comumente aconteciam no formato presencial, tem um alto impacto na formação e atualização dos profissionais em diversas áreas, além de permitir discutir as tendências do mercado de trabalho e inovação tecnológica. É necessário que as dificuldades de realização destes eventos no formato virtual sejam discutidas, além dos pontos positivos e negativos do uso das TICs durante seu planejamento, execução e avaliação. Nesse contexto, este artigo apresenta os resultados da adaptação da Jornada de Informática do Maranhão realizada bienalmente para o formato virtual. O evento foi organizado no espaço de um mês e meio e foi executado em três semanas corridas, contando com atividades como: apresentação de trabalhos, maratona de programação, competição de objetos educacionais, discussões online, webinários e tutoriais de temas atuais, e campeonato de esportes eletrônicos. Ao todo, 174 inscritos participaram das atividades realizadas assistindo as atividades e interagindo nas plataformas do evento. Para avaliar o impacto das atividades no formato online, foi aplicado um questionário ao final do evento que cotou com a resposta de 45 dos participantes. Os resultados indicaram a avaliação positiva do evento para todas as atividades acadêmicas realizadas, as vantagens de ter realizado o evento de forma virtual e gratuita; e a disponibilização do conteúdo para futura consulta. Além disso, oportunidades de melhoria como uso de recursos para disponibilizar informações adicionais ao vivo, melhoria na divulgação e propiciar uma maior interação entre os participante.
Avaliando a Especificação das Ocorrências das Características Transversais em Software Embarcado
Authors: de Oliveira Rodrigo , Wehrmeister Marco Aurélio
Published: December 2020

A engenharia de software embarcado vem evoluindo rapidamente ao longo dos últimos anos, em especial para lidar com o aumento da complexidade associada a grande quantidade de requisitos funcionais e características transversais associadas aos requisitos não-funcionais. O processo de identificar e especificar a seleção de pontos onde as características transversais devem ser tratadas vem sendo amplamente discutido desde meados dos anos 90, especialmente no contexto da Aspect-Oriented Software Development (AOSD) e modelagem. No entanto, a compreensão de tais especificações é muitas vezes difícil, pois a sintaxe e a semântica das linguagens utilizadas, principalmente as linguagens visuais, não permitem intuir facilmente o significado dos símbolos usados. Tal situação produz artefatos difíceis de compreender e manter. Portanto, o processo de localizar, identificar, e especificar os pontos onde as características transversais devem ser tratadas e chave no projeto de software embarcado, pois pode levar à problemas no desenvolvimento e, principalmente, na integração dos componentes do software do sistema. Este trabalho apresenta uma avaliação empírica com o objetivo de avaliar a compreensão da especificação de seleção de POCT em sistemas embarcados de forma indireta através da avaliação ao dos efeitos cognitivos e das propriedades de percepção das notações. Foram avaliadas três notaçõees, duas gráficas (JPDD e Theme/UML) e uma textual (AspectJ), que foram usadas para especificar implícita e explicitamente a seleção de POCT (para 15 pontos distintos) em três projetos de software embarcados diferentes que representam aplicações reais no contexto de sistemas de automação. Para tal, propõe-se um modelo de qualidade baseado no framework conceitual “Physics of Notation” (PON). Foram usadas nove métricas para quantificar as propriedades perceptuais na especificação da seleção de POCT, sendo que algumas métricas foram criadas e outras representam conceitos dentro dos princípios do PON. Os resultados dos experimentos mostram como cada uma das notações impacta na compreensão das especificações criadas. Foram encontradas evidencias empíricas de que a especificação gráfica das seleções dos POCT tem pouca discriminação sobre a eficácia cognitiva das representações visuais (conforme o framework PON) e, portanto, os indícios apontam para a conclusão de que o uso de notações visuais para especificar a seleção de POCT é um processo inconsciente e sujeito a ambiguidades tanto na especificação dos artefatos quanto na compreensão e interpretação deles.
El retorno de la inversión en las relaciones públicas, una revisión bibliográfica
Authors: Lopez-del-Castillo-Wilderbeek Francisco Leslie
Published: December 2020

This research has carried out a systematized bibliographic review to analyze how the return on investment (ROI) in communication, and specifically in public relations, has been theoretically treated.
The financial measurement of communication outcomes represents a topic of great interest for the academic community because organizations need to know the real results of their communication efforts. At the same time, economic measurement turns out to be a variable that can be understood by the management of the organizations and allows them to know where the money is being spent.
However, despite more than forty years of theoretical work, a homogeneous nor globally accepted solution has not yet been achieved.
The bibliographical study of the return on investment in communication, and especially in public relations, shows the difficulty of turning the success of the activity of public relations professionals into money. On the one hand, there is no doubt that the ROI is directly related to financial data; on the other hand, in communication it is usual to introduce non-economic values to evaluate the results achieved. The bibliographical results indicate in the first instance that, on a quantitative level, the economic aspect is predominant in the calculation of the ROI (96.3%).
In this context measurement by equivalence in advertising (AVE) is an economic model as used by professionals as it is rejected by researchers. It is based on comparing the cost of a presence in the media with the equivalent cost if it were advertising. Nevertheless, this model is criticized for the differences between advertising (a completely controlled message) and publicity (a message that is altered by the media).
However, taking the previous works about the subject, it can be said that the evaluation of public relations actions can be dealt with from the perspective of opportunity cost: the loss of other alternatives when one alternative is chosen.
In this way, the evaluation of the cost of a traditional advertising action can be compared with the cost of other options available to public relations professionals. For example, native advertising is a resource of public relations teams whose cost can easily be compared to traditional advertising. Native advertising is a paid promotion that matches the audience's consumption and contains information of interest to the advertiser.
Hence opinions that reject the advertising equivalence measurement (AVE) are not justified when the product generated by public relations has the characteristics of native advertising because in both cases (advertising vs. native advertising) the professional can exactly compare the investment made with one instead of the other.
Investigating the Effect of Near Infra-Red Spectroscopy (NIRS) on Early Diagnosis of Cardiac Surgery-Associated Acute Kidney Injury
Authors: Javaherforooshzadeh Fatemeh , Bhandori Hojatolah , Jarirahmadi Sara , Bakhtiari Nima
Published: December 2020

Background: Cardiac surgery-associated acute kidney injury (CSA-AKI) is a major adverse effect of cardiac surgery. The early detection of this complication can improve the quality of postoperative care and help prevent this phenomenon. Methods: In this prospective descriptive-analytical study, 148 patients were enrolled, 107 of whom were selected for analysis between February and September 2019 in the Cardiac Surgery Unit of Golestan Hospital, Ahvaz, Iran. Kidney tissue oxygen saturation was measured at multiple definite times during surgery. Hemoglobin, blood urea nitrogen, creatinine, and lactate were measured during and 48 hours after the surgery. Results: Forty-one patients were diagnosed with CSA-AKI according to the KDIGO criteria. Parametric and non-parametric analyses showed no significant difference between the CSA-AKI and non-CSA-AKI groups in the demographic parameters. Repeated measures ANOVA showed no significant difference in parameters, except for BUN. Repeated measures ANOVA showed a significant difference between both groups and time factors (P < 0.001, P = 0.0006, respectively). The ROC curve analyses showed that in a single point of time, the difference in the middle of CPB time from baseline had a high value in the prediction of AKI (AUC: 0.764; CI: 0.57 - 0.951). Conclusions: Kidney saturation monitoring could be considered in cardiac surgery for the rapid detection of CSA-AKI. Although kidney tissue saturation is not correlated directly to the arterial oxygen saturation, the physician and the surgery team can predict the chance of acute kidney injury.
An Unexpected Finding of Gastrointestinal Stromal Tumors During Laparoscopic Sleeve Gastrectomy; How to Deal? How Much Safety Margin Needed?
Authors: Sieda Bassem M , Habeeb Tamer A. A. M.
Published: December 2020

Background: There is an increasing incidence of coincidental gastric gastrointestinal stromal tumors (GIST) during a laparoscopic sleeve gastrectomy (LSG). Resection with negative margin R0 is the safest and most proper treatment. Objectives: The incidence of GIST in patients undergoing LSG and resection with a 1- to 2-cm safety margin was validated and analyzed. The primary endpoint is that can simultaneous excision be oncologically adequate or not? How much GIST is supposed to be far from a staple line? Methods: The present prospective study included 338 patients with body mass index (BMI) ≥ 35. All patients underwent LSG without known history or imaging reveal GIST. Resection was done with a safety margin of 1 to 2 cm away from the stapled margin and, then, sent for histopathology and immunohistochemically staining. Results: A total of 17 patients (5%) had coincidental GIST. The size was T1 in 88.2% of patients; 16 patients were staged as IA according to the American Joint Committee on Cancer (AJCC TNM). Safety margin was ≤ 1 cm for 3 patients to avoid incorporation in staple line and 14 patients (82.3%) had 2 cm safety margin. Resection margin in biopsy revealed positive resection margin R1 for 2 patients, whose safety margin was only 1 cm or less. A total of 15 patients had a negative margin (R0), whose safety margin was 2 cm. Conclusions: Any incidental GIST can be removed safely during LSG as long as it is far from the staple line with at least a 2-cm safety margin and negative resection margins without changing the procedure. Margins less than 1 cm are associated with adverse prognostic factors.
Impulsive Behavior as a Mediator Between Childhood Maltreatment and Emotional Disorders
Authors: Azarmehr Rabeeh , Shalchi Behzad , Ahmadi Ezatollah
Published: December 2020

Background: Impulsive behavior plays an important role in mediating the relationship between childhood maltreatment and emotional disorders. Objectives: This study aimed to determine the relationship between childhood maltreatment and emotional disorders, considering the mediating role of impulsive behavior. Methods: This descriptive cross-sectional study was conducted on a statistical population, including all students of Azarbaijan Shahid Madani University, Tabriz, Iran. A total of 316 students were selected randomly and completed the Inventory of depression and anxiety symptoms (IDAS), Impulsive Behavior Scale (UPPS-P), and Childhood Trauma Questionnaire (CTQ). The collected data were analyzed in SPSS version 22 and LISREL. Results: The correlation coefficient showed a significant relationship between childhood maltreatment and emotional disorders, and the structural equation model exhibited a good fit to the data (GFI = 0.9, AGFI = 0.86, CFI = 0.99, and RMSEA = 0.07). Conclusions: The results showed that impulsive behavior played an important role in mediating the relationship between childhood maltreatment and emotional disorders.
Factors Associated with Seasonal Influenza Vaccination Among Nursing Staff of Three Teaching Hospitals Affiliated to Kerman University of Medical Sciences, Iran
Authors: Khalooei Ali , Shafiei Bafti Mehdi
Published: December 2020

Background: Although seasonal influenza vaccination decreases infection rate and associated complications, its coverage rate is suboptimal in healthcare workers worldwide. Objectives: The present study aimed at assessing the predictors of influenza vaccination and reasons for accepting or refusing it among nursing staff. Methods: The present study was conducted from February to March 2019 on nurses of three teaching hospitals affiliated to Kerman University of Medical Sciences in the Southeast of Iran. Data were collected using a validated questionnaire, including demographic data, knowledge, and attitude toward influenza and its vaccine, and reasons for accepting or refusing the vaccine. Data were analyzed by SPSS version 22. Independent samples t- and the chi-squared tests and the binary logistic regression were employed for data analysis. Results: The influenza vaccination coverage rate was 10.1% among the nursing staff. Male gender (adjusted odds ratio (AOR) = 4.77, 95% confidence interval (CI) =2.13 - 10.64), receiving a recommendation for influenza vaccination in hospital (AOR = 1.86, 95% CI = 1.06 - 3.26), influenza vaccination of the family members (AOR = 2.61, 95% CI = 1.55 - 4.41), and a higher score of attitude toward influenza vaccination (AOR = 1.05, 95% CI = 1.03 - 1.07) increased the likelihood of influenza vaccination in the nursing staff. Fear of vaccine adverse effects (64.7%), lack of trust in vaccine manufacturers (36.0%), and being healthy (29.7%) were the most common reasons for refusing vaccination. Likewise, self-protection (79.6%), patient protection (73.0%), and family protection (72.4%) were the most common reasons for undergoing vaccination. The odds of influenza vaccine uptake was four times more among males than females (AOR = 4.77, 95% CI = 2.13 - 10.64), and odds of influenza vaccination was 1.86 times more among nursing staff receiving recommendations for influenza vaccination in hospital than the ones not receiving such recommendations (AOR = 1.86, 95% CI = 1.06 - 3.26). Also, odds of influenza vaccination increased 2.73 times in nursing staff whose family members received influenza vaccine (AOR = 2.61, 95% CI = 1.55 - 4.41). Furthermore, the model showed that one unit increase in the attitude score increased odds of influenza vaccination by 1.05 units (AOR = 1.05, 95% CI = 1.03 - 1.07). Conclusions: The influenza vaccination rate was suboptimal among the nursing staff. Also, there were poor knowledge and improper attitude toward influenza and its vaccine among healthcare workers. Therefore, appropriate policies should be made at national and regional levels on increasing the rate of influenza vaccination.
The public opinion: Escape from responsibility and guilt
Authors: Dobrosavljev Duška
Published: December 2020

The aim of the first part of the text public opinion: escape from responsibility and guilt is to raise the question: Do we and at which point we become guilty by avoiding our responsibility? Do we have right to remain silent even when we are faced with an extreme case of injustice? By determining concepts of responsibility and guilt, this text tries to outline some limits that must always be respected. The article particularly focuses on the role of people that are professionally occupied with humanities. The second part of the text deals with the widening of the concept of responsibility that presented German philosopher Hans Jonas in his book The Imperative of Responsibility. Jonas shows how the concept of responsibility in contemporary circumstances got new and relevant horizons and nuances. Warning of the danger that we place ourselves in front of by neglecting our responsibility, Jonas insists on essential role of humanities in the world, individual responsibility, knowledge and science that are public, open and accessible to everyone.
Constitutional foundations of Swiss civil legislature
Authors: Nikolić Dušan
Published: December 2020

The modern Swiss civil legislation is based on the constitutional principles which are not different from those proclaimed in 1798 during the French domination. It took cantons two centuries to accept the full unification of civil law, the unification that originally Napoleon intended to impose by force. What was inconceivable and unacceptable at the end of XVIII century is part of everyday's life today. However, it was a long and difficult task to achieve the uniform civil law. It took a lot of time, many compromises and wise political decisions to overcome deeply rooted legal particularism. However, at the turn of the new millenium, under the influence of social changes, the full circle is finally closed and what once was only the idea is now accomplished: the Swiss Confederation has a uniform private law today. Legal developments in Yugoslavia have undertaken a completely different direction. The process of particularization obviously has not been ended. The latest constitutional concept provides for the delegation of legislative competences from the federal to state levels. Therefore, the legal particularism in (he area of the civil law seems to be an inevitable consequence. The latest world trends are quite opposite to the directions carried out within our legal system. Unification of domestic legislation and its adjustment to regional and world standards should be priority in the times we live in. The experience of the Swiss Confederation certainly provides such an example.
The notion of joint possession
Authors: Popov Danica
Published: December 2020

Joint possession exists when two or more persons share actual possession of a physically indivisible thing or a right. Pursuant to the Article 70(4) of the Property Act and its definition of a possession, "two or more persons can have possession of a thing or right", is incomplete as it does not comprise the reference to "the same thing or right" or "one thing or right". The actual possession between two or more joint possessors is not divided but the exercise of rights can be organized in different ways: a) actual possession on a thing can be shared simultaneously by possessors; b) actual possession on a thing can be shared consecutively; c) one person can have the actual possession of a thing on behalf of all possessors, including the occupant; d) a third person can have the actual possession of a thing on behalf of all persons entitled to constructive possession.
Case note: Kutić v. Croatia
Authors: Padežanin Radmila
Published: December 2020

Velik značaj presude Evropskog suda u slučaju Kušić protiv Republike Hrvatske proizlazi iz njenog uticaja na Vladu Republike Hrvatske u donošenju relevantnih zakona u oblasti naknade štete pričinjene terorističkim aktom i delovanjem vojnih i redarstvenih snaga tokom rata. Evropski sud je u ovom slučaju ustanovio povredu člana 6. Konvencije o osnovnim ljudskim pravima i slobodama jer je suspenzijom člana 180. Zakona o obaveznim odnosima Republike Hrvatske, a nedonošenjem drugih propisa u oblasti naknade štete, povređen pristup sudu. Međutim, u skladu sa novodonetim Zakonom o odgovornosti za štetu nastalu usled terorističkih akata i javnih demonstracija, porodica Kutić i dalje neće imati mogućnost da se pred domaćim sudom raspravlja o njihovom zahtevu jer oštećenik ima pravo samo na naknadu one štete koja je posljedica smrti, tjelesne povrede ili oštećenja zdravlja. Očigledno je da je Zakon protivustavan, između ostalog i iz razloga što predviđa retroaktivnu primenu na postupke pokrenute pre njegovog donošenja, i može ce očekivati da će uskoro biti pokrenut zahtev za ocenu njegove ustavnosti. Činjenica je da je rad Ustavnog suda poprilično spor, ukazuje da se loše zakonsko rešenje može pripisati cilju kupovine vremena za rešavanje ovako velikog problema. Međutim, u slučaju Kutić preostaje i mogućnost ponovnog pokretanja postupka pred Sudom u Strazburu.
Execution of a preliminary agreement on sale and purchase of immovable property
Authors: Tamaš Vladimir
Published: December 2020

Bez obzira na različita rešenja u uporednom pravu i postojeće dileme u pravnoj teoriji predugovor je zadržao svoje mesto između pregovora i zaključenja glavnog ugovora, a sa najbitnijom karakteristikom da se njime ugovorne strane prvenstveno obavezuju na zaključenje drugog, glavnog ugovora. Ova osnovna karakteristika predugovora opredeljuje njegovo dejstvo, mogućnost izvršenja i prestanka, te posledice povrede njegovih odredbi. Više pažnje svakako i zbog profesionalnog opredeljenja autora, posvećeno je spornim pravnim pitanjima kroz analizu aktuelne sudske prakse, a sa osvrtom i na sporna teorijska pitanja, kako bi se ukazalo na njihovu povezanost i potrebu korišćenja rešenja i teorije i prakse. Pri rešavanju sporova nastalih povredom predugovora o prometu nepokretnosti trebalo bi kroz utvrđenje prave volje ugovornih strana težiti da se ostvari promet nepokretnosti kao osnovni cilj ugovaranja, pri čemu treba voditi računa o osnovnim načelima obligacionog prava, posebno načelu savesnosti i poštenja i načelu zabrane zloupotrebe prava. Nalaganjem suda da se pristupi zaključenju glavnog ugovora treba omogućiti prenos prava svojine na taj način što će presuda po svom sadržaju moći da zameni ugovor o prometu nepokretnosti ukoliko dužnik ne ispuni svoju obavezu zaključenja glavnog ugovora u roku određenom presudom. Povrede predugovora o prometu nepokretnosti mogu biti osnov za ostvarivanje prava na naknadu štete pod uslovima propisanim za ugovornu odgovornost, pri čemu treba uzeti u obzir i specifičnosti predugovora, kao ugovora koji prethodi zaključenju glavnog ugovora.
Kant's metaphysics of law
Authors: Basta Danilo
Published: December 2020

The history of reception and the history of interpretation of Kant's legal deliberation are not the same even after two centuries. This was not only due to the recipients and interpreters of Kant's thoughts but also and above all due to Kant, i.e., the content and the spirit of his philosophy. The law of the state, the international law, and the cosmopolitan law are the ways to approach the eternal peace, which was considered by Kant as the final goal of the entire international law. The existence of the State is based on the idea of the Initial Agreement. According to Kant, in the Initial agreement all the individuals abandoned their external freedom in order to attain the freedom in a legal order as members of the political union. Kant did not always succeed to stay on the level of his own legal and political principles, and hence the light of his philosophy is sometimes covered with the dark shadows.
Much ado about nothing: Multiple imputation to balance unbalanced designs for two-way analysis of variance
Authors: van Ginkel Joost R. , Kroonenberg Pieter M.
Published: December 2020

In earlier literature, multiple imputation was proposed to create balance in unbalanced designs, as an alternative to Type III sum of squares in two-way ANOVA. In the current simulation study we studied four pooled statistics for multiple imputation, namely D₀, D₁, D₂, and D₃ in unbalanced data, and compared these statistics with Type III sum of squares. Statistics D₀ and D₂ generally performed best regarding Type-I error rates, and had power rates closest to that of Type III sum of squares. However, none of the statistics produced power rates higher than Type III sum of squares. The results lead to the conclusion that for multiply imputed datasets D₀ and D₂ may be the best methods for pooling the results of multiparameter estimates in multiply imputed datasets, and that for unbalanced data, Type III sum of square is to be preferred over using multiple imputation in obtaining ANOVA results.
História do Tempo Presente e América Latina: Uruguai - Entrevista com Jaime Yaffé
Authors: Yaffé Jaime , Pereira de Oliveira Carlos Eduardo
Published: December 2020

O historiador Jaime Yaffé é docente da Facultad de Ciencias Sociales da Universidad de la República, em Montevidéu, e investigador do Instituto de Ciência Política da mesma universidade. Licenciou-se em História pelo Instituto de Profesores Artigas de Montevideo, mestre em Ciência Política e doutor em Ciências Sociais. É membro do Sistema Nacional de Investigadores do Uruguai (SNI), na área de Ciências Sociais. Tem como linha de pesquisa os estudos sobre a história contemporânea uruguaia, com foco na ditadura civil-militar uruguaia, seus antecedentes e seus desdobramentos no presente. Destaco as pesquisas sobre a trajetória da Frente Ampla na política nacional do Uruguai, analisando a construção de uma identidade partidária frenteamplista no pós-ditadura, e dialogando com as temáticas da memória e usos do passado.
Securing picture archiving and communication system (PACS) cybersecurity for the healthcare sector
Authors: Cawthra Jennifer , Hodges Bronwyn , Kuruvilla Jason , Littlefield Kevin , Niemeyer Bob , Peloquin Chris , Wang Sue , Williams Ryan , Zheng Kangmin
Published: December 2020

Medical imaging plays an important role in diagnosing and treating patients. The system that manages medical images is known as the picture archiving communication system (PACS) and is nearly ubiquitous in healthcare environments. PACS is defined by the Food and Drug Administration (FDA) as a Class II device that provides one or more capabilities relating to the acceptance, transfer, display, storage, and digital processing of medical images. PACS centralizes functions surrounding medical imaging workflows and serves as an authoritative repository of medical image information.
Carrier selective contacts:a selection of high efficiency silicon solar cells
Authors: Xiao You-Peng  , Gao Chao  , Wang Tao  , Zhou Lang  ,   Institute of Photovoltaic, Nanchang University, Nanchang 330031, China
Published: December 2020

Solar cell has two basic units:the photon absorption layer and the contact layer. The contact layer is a region between the highly recombination-active metal interface and the photon absorption layer. It is vital to reduce the recombination loss between the photon absorption layer and the contact layer in pursuit of the higher conversion efficiency of silicon solar cell. In recent years, carrier selective contact is arousing research interest in photovoltaic industry because it is deemed as one of the last remaining obstacles in approaching to the theoretical efficiency limit of silicon solar cell. In this paper, three different types of carrier selective contacts are analyzed, which includes:1) sandwiching a heavily doped thin layer between the photon absorption layer and the metal interface, which is the so-called emitter or back surface field; 2) aligning the conduction bands or the valence bands of two materials; 3) inducing the band bending through a high work function metal oxide contacting crystalline silicon. Based on one-dimensional solar cell simulation software wxAMPS, three different silicon solar cell structures are numerically simulated, which includes:1) diffused homojunction silicon solar cell[(p+)c-Si/(n)c-Si/(n+)c-Si]; 2) silicon heterojunction solar cell with amorphous silicon thin films[(p+)a-Si/(i)a-Si/(n)c-Si/(i)a-Si/(n+)a-Si]; 3) silicon heterojunction solar cell with metal oxide thin films[(n)MoOx/(n)c-Si/(n)TiOx], then the energy band structures and the spatial distributions of carrier concentrations of solar cells in the dark are discussed. The simulation results show that the key factor of carrier selective contacts is the asymmetric spatial distribution of the carrier concentrations, i.e. the asymmetric conductivities of electrons and holes. This leads to the formation of high resistance to electrons and low resistance to holes, or high resistance to holes and low resistance to electrons, so the holes will go through the contact easily and the electrons will be blocked simultaneously, or the electrons will go through the contact easily and the holes will be blocked simultaneously. Therefore a hole selective contact or a electron selective contact is formed, respectively.
Quantum spin Hall effect in metamaterials
Authors: Long Yang  , Ren Jie  , Jiang Hai-Tao  , Sun Yong  , Chen Hong  ,   Center for Phononics and Thermal Energy Science, School of Physics Science and Engineering, Key Laboratory of Advanced Micro-structure Materials, MOE, Tongji University, Shanghai 200092, China
Published: December 2020

Quantum spin Hall effect (QSHE) of electrons has improved the development of condensed matter researchnowadays, which describesone kind of spin-dependent quantum transport behavior in solid state. Recently, a variety of theoretical and experimental work has revealed that Maxwell equations, which is formulated 150 years ago and ultimately describeproperties of light, can exhibit an intrinsic quantum spin Hall effect of light. The evanescent wave supported on the interface among different media behaves strong spin-momentum locking. With the rapid development of new optics materials, metamaterials, we can not only adjust the optical parameters of media arbitrarily, but also introduce a lot of complex spin-orbit interaction mechanism. Based on metamaterials, the essential physical mechanism behind quantum spin Hall effect of light can be understood deeply and verified easily. The purpose of this review is to give a brief introduction to quantum spin Hall effect of light in metamaterials. These include, for example, the physical essence of QSHE of light, the topological interface mode between permittivity negative and permeability negative metamaterials, QSHE in topological circuits.
PIC/MCC simulation of breakdown dynamics inside high power microwave output window
Authors: Zuo Chun-Yan  , Gao Fei  , Dai Zhong-Ling  , Wang You-Nian  ,   Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams(Ministry of Education, School of Physics, Dalian University of Technology, Dalian 116024, China
Published: December 2020

High power microwave (HPM) has important applications in controlled thermonuclear fusion heating, microwave high-gradient accelerator, high-power radar, directed-energy weapon, super jammer, impact radar, etc. The window breakdown of HPM has been extensively studied, and some research progress in this respect has been made. However, the researches on the transition of window breakdown from multipactor discharge to rf plasma are still not enough in-depth. Especially, the influences of microwave frequency and microwave amplitude during breakdown need further studying. This paper focuses on the process of dielectric multipactor and background argon ionization during the discharge breakdown near the HPM dielectric window/vacuum interface. A one-dimensional-spatial-distribution-and-three-dimensional-velocity-distribution (1D3V) electrostatic model with using particle-in-cell simulation is adopted in present work. The model includes secondary electron emission, electrostatic field induced by the remaining positive charge on the dielectric window, the motion of charged particles under electrostatic and microwave field, and the collision process between electron and background gas, and the corresponding PIC/MCC code is also developed. We examine the effects of gas pressure, microwave frequency and microwave amplitude on discharge breakdown. It is found that there exists only electron multipactor process during the discharge breakdown on dielectric window in vacuum. At low pressures (10 mTorr, 500 mTorr) and slightly high pressure (10 Torr), electron multipactor and gas ionization are coexistent. However, at an extremely high pressure (760 Torr), the gas ionization dominates the breakdown process. At the same time, the position of plasma density peak moves away from the dielectric window as the gas pressure increases, which is the consequence of the competition between secondary electron multiplication on the dielectric window and gas ionization in the body region. It can be seen that the advantage of gas ionization gradually increases as the gas pressure increases. In addition, it is also observed that at 500 mTorr, the moment of gas ionization moves forward first and then backward with the increase of the microwave amplitudes or the microwave frequency, especially when the increment of frequency is numerically twice that of the amplitude, gas ionization occurs earliest. This phenomenon is explained by the secondary electron emission model. Meanwhile, the results show that the position of plasma density peak from gas ionization gradually approaches to the dielectric window as the microwave amplitude increases. However, with continually increasing the microwave frequency, the plasma density peak moves away from the dielectric window first and then approaches to the dielectric window.
Research progress of topological quantum states in iron-based superconductor
Authors: Hao Ning  , Hu Jiang-Ping  ,   Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China;,   Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;,   Kavli Institute of Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

Iron-based superconductors and topological quantum states have been two important research frontiers in condensed matter physics in recent years. It is a very significant question whether the nontrivial topological phenomena can occur in iron-based superconductors. In this paper, the basic characteristics of the electronic structure of iron-based superconducting are analyzed from three aspects:crystal symmetry, effective model near the high symmetry points in Brillouin zone, and spin-orbit coupling interaction. On this basis, this paper focuses on how the nontrivial topological quantum states occur in the normal state, the states with long-range order near superconducting state and the superconducting state. Furthermore, the relevant theoretical models and results are introduced in detail, the related experimental progress is reviewed, and the development in this field is prospected.
Simulations and time-domain spectroscopy measurements for terahertz radar-cross section
Authors: Zhang Xu-Tao , Que Xiao-Feng , Cai He , Sun Jin-Hai , Zhang Jing , Li Liang-Sheng , Liu Yong-Qiang ,   Science and Technology on Electromagnetic Scattering Laboratory, Beijing 100854, China,   School of Electronic Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China
Published: December 2020

Terahertz time-domain spectroscopy technology has a wide range of applications in security inspection, nondestructive testing, biomedical, etc. But its application to target characteristics has been under debates, because there exist so many differences between terahertz continuous wave and ultra short pulse wave (single pulse width about 1 ps). For investigating the problem of quantitatively measuring the terahertz radar cross section, in this paper, a terahertz time domain spectroscopy scattering measurement system is built based on the technology of terahertz time domain spectroscopy. After system optimization and error minimization of location and system, time domain echoes of targets, such as sphere, disk, cylinder and complex targets, are measured. After the process of fast Fourier transformation and calibration, radar cross sections of the above-mentioned targets in a frequency range of 0.2–1.6 THz are calculated. Furthermore, the surface integral equation method and multilevel fast multipole algorithm are used to simulate the radar-cross section (RCS) results. The measured radar cross section results are compared with the simulations, and their error is less than 3 dB. The error arises mainly from the location and uneven distribution of terahertz wave on quiet zone. Generally, it is acceptable though there is still much work to do. The accuracy of RCS measurement of terahertz time domain is varified. All those are progressing in terahertz time domain spectroscopy technology used in target characteristics. Moreover, the methods of improving dynamic range in high frequency and enlarging quiet zone are the focus of follow-up studies.
Electro-static discharge protection analysis and design optimization of interlayer Cu interconnection in InGaZnO thin film transistor backplane
Authors: Ma Qun-Gang , Wang Hai-Hong , Zhang Sheng-Dong , Chen Xu , Wang Ting-Ting ,   School of Electronic and Computer Engineering, Peking University, Shenzhen 518055, China,   School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China,   Nanjing CEC Panda LCD Technology Co., Ltd., Nanjing 210033, China,   Nanjing CEC Panda FPD Technology Co., Ltd., Nanjing 210033, China
Published: December 2020

The InGaZnO thin film transistor (IGZO TFT) backplane combined with Cu interconnection has nearly an order of magnitude lower in the ability to withstand voltage than that of traditional a-Si TFT backplane on the production line. The breakdown voltage of Mo/Cu interconnection between data line and gate line is only about 60% of that of traditional a-Si TFT backplane. The electrostatic discharge (ESD) breakdown of Mo/Cu:SiNx/SiO2:Mo/Cu structure has become an important factor affecting the normal display of IGZO TFT ultra high definition (UHD) panel. We find that the anti-ESD damage ability of IGZO TFT devices needs matching with the anti-ESD damage ability of interlayer Cu interconnection in order to achieve a high-robustness IGZO TFT backplane. The position of ESD damage in IGZO TFT backplane is commonly in the climbing place where the data line crosses the scanning line. In this paper, a Cu diffusion model is proposed to explain the mechanism for the ESD failure of interlayer Cu interconnection. The Cu metal in gate line diffuses into SiNx/SiO2 gate insulator, and Cu metal at the corner of data line, where the date line crosses the gate line, diffuses into SiO2 film on the date line. The selection conditions of three kinds of protection architectures for ESD protection circuits around Cu interconnection, i.e. R-type, R-half-type, and Diode-type protection architectures, are proposed. On the basis of process optimization such as Cu metal film forming and Cu metal interface treatment, an ESD protection method for the Cu interconnection periphery of IGZO TFT backplane with high robustness is proposed. For the stable production process of IGZO TFT, combined with the design window of ESD protection circuit, the peripheral ESD protection circuit of Cu interconnect is designed with diode-type protection circuit on the IGZO TFT backplane of large-sized UHD and QUHD panel, which effectively improves the effect of interlayer Cu interconnection of IGZO TFT backplane on ESD damage. Through the production verification, it is proved that the metal diffusion of Cu interconnection on IGZO TFT backplane is the fundamental reason for reducing the anti-ESD damage ability of Mo/Cu:SiNx/SiO2:Mo/Cu structure. The rationality of the proposed ESD damage model for interlayer Cu interconnection is verified, which provides a theoretical basis for subsequent IGZO TFT backplane design with high robustness.
Modulation of propagating surface plasmons
Authors: Zhang Wen-Jun , Gao Long , Wei Hong , Xu Hong-Xing ,   Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China,   School of Physics and Technology, Wuhan University, Wuhan 430072, China,   Songshan Lake Materials Laboratory, Dongguan 523808, China
Published: December 2020

The diffraction limit of light greatly limits the development of conventional optical devices, which are difficult to be miniaturized and integrated with high density. Surface plasmons, electromagnetic modes at the metal-dielectric interface, can concentrate light into deep subwavelength dimensions, enabling the manipulation of light at the nanometer scale. Surface plasmons can be used as information carrier to transmit and process optical signals beyond the diffraction limit. Therefore, nanodevices based on surface plasmons have received much attention. By modulating surface plasmons, the modulation of optical signals at nanoscale can be realized, which is important for the development of on-chip integrated nanophotonic circuits and optical information technology. In this article, we review the modulations of propagating surface plasmons and their applications in nano-optical modulators. The wave vector of propagating surface plasmons is very sensitive to the dielectric function of the metal and the environment. By tuning the dielectric function of the metal and/or the surrounding medium, both the real and imaginary part of the wave vector of surface plasmons can be modified, leading to the modulation of the phase and propagation length of surface plasmons and thereby modulating the intensity of optical signals. We first introduce the basic principles of different types of modulations, including all-optical modulation, thermal modulation, electrical modulation, and magnetic modulation. The all-optical modulation can be achieved by modulating the polarization and phase of input light, pumping optical materials, changing the dielectric function of metal by control light, and manipulating a nanoparticle by optical force to modulate the scattering of surface plasmons. The modulation based on thermal effect depends on thermo-optic materials and phase-change materials, and the temperature change can be triggered by photothermal effect or electrical heating. For electrically controlled modulation, Pockels electro-optic effect and Kerr electro-optic effect can be employed. Electrical modulation can also be realized by controlling the carrier concentration of semiconductors or graphene, using electrochromatic materials, and nanoelectromechanical control of the waveguide. The modulation of surface plasmons by magnetic field relies on magneto-optic materials. We review recent research progresses of modulating propagating surface plasmons by these methods, and analyze the performances of different types of plasmonic modulators, including operation wavelength, modulation depth or extinction ratio, response time or modulation frequency, and insertion loss. Finally, a brief conclusion and outlook is presented.
Sound insulation performance of Helmholtz cavity with thin film bottom
Authors: He Zi-Hou , Zhao Jing-Bo , Yao Hong , Chen Xin ,   Graduate School, Air Force Engineering University, Xi’an 710051, China,   Department of Basic, Air Force Engineering University, Xi’an 710051, China
Published: December 2020

Aiming at the isolation of low-frequency noise, an acoustic metamaterial is designed based on Helmholtz cavity and thin film structure. It consists of a Helmholtz cavity with film bottom and the mass block attached to the cavity. By the finite element method, the transmission losses and resonance frequencies of metamaterials in a frequency range of 20－1200 Hz are calculated and also verified experimentally. The results show that the metamaterial has great sound insulation performance in the frequency range. There are six sound insulation peaks, of which the two sound insulation peaks below 100 Hz have the transmission losses of 44.29 dB and 67.43 dB, respectively. The maximum transmission loss in the whole frequency range is 90.18 dB. Comparing with the normal Helmholtz cavity or thin film acoustic metamaterial or traditional material, the sound insulation performance of the metamaterial is improved greatly. By analyzing the resonance and vibration mode diagram at the sound insulation peaks comprehensively, the sound insulation mechanism of the metamaterial is further explored. The results show that many resonance modes have no effect on transmission loss only when the resonance mode can be coupled with the incident wave and is not an antisymmetric mode which can affect the transmission loss. The transmission and reflection coefficient of the metamaterial are calculated by the finite element method, and through the method for retrieving effective properties, the effective mass density and effective modulus are obtained. It is found that there is a negative effective mass density at the sound insulation peak, meanwhile the effective modulus is close to zero. The generation mechanism of abnormal equivalent parameters is analyzed from the energy view point. The acoustic impedance of the metamaterial is obtained by an equivalent circuit method, through which the first resonance frequency is calculated relatively accurately. According to the results of the previous study on sound insulation mechanism, the effect of the eccentric mass unit on the sound insulation performance of metamaterial is studied. It is found that the eccentric mass can greatly reduce the antisymmetric resonance mode and increase the sound insulation peak of the structure, which is also verified experimentally. The results provide a reference for designing the acoustic metamaterials.