bluuebunny/crossref_metadata_2025_split huggingface dataset:
High Temperature, Time Domain Sensor Interface based on Phase Shifter
Authors: Chabchoub Emna , Badets Franck , Masmoudi Mohamed , Nouet Pascal , Mailly Frédérick 
Published: July 2017

Abstract
This paper presents resistive sensor interface circuit for high temperature applications. The presented circuit has a time-domain differential architecture. It is based on the use of voltage-controlled phase shifters to perform the signal conditioning in time domain which makes it more robust the environment's parameters, in particular the temperature. The output of the presented senor interface depends only on relative parameters of the circuit, therefore; a low sensitivity to temperature variations is achieved. The low variation of the circuit output versus temperature has been demonstrated by simulations and measurements of the fabricated prototype.
SOI Operational Amplifier Applications in 300°C Operating Environment
Authors: Chen Cheng-Po , Stoica Lucian , Andarawis Emad , Simpson Russell 
Published: July 2017

Abstract
A custom designed SOI operational amplifier (opamp) is used in two application circuits and characterized up to 300°C: 1. An instrumentation amplifier (in-amp) with a differential voltage gain of 100, and 2. A transimpedance amplifier (TIA) with a gain of 1.2 giga Ohm, used to sense picoamp level signals. The opamp operates with a 5-volt supply, and has rail-to-rail inputs and outputs. The open loop gain of the opamp is about 100 dB at room temperature and stays above 60 dB at 300°C.
The in-amp uses the classic three operational amplifier (opamp) architecture with off-chip feedback resistors. The closed loop gain of the in-amp remains stable at 100, up to 250°C, and drops to 95 at 300°C. Temperature dwell test shows the in-amp maintaining stable functionality at 300°C for at least 1000 hours.
The TIA also incorporates a silicon carbide diode to achieve gain compression by lowering the feedback gain when the input signal is higher, thus allowing a higher dynamic range input before the circuit output saturates.
A High Temperature Linear Wideband Power Amplifier for a Downhole Communication System
Authors: Hiemstra S. Reza , Kerrigan Brannon M. , Ha Dong S. 
Published: July 2017

Abstract
In order to reach previously untapped wells, the oil and gas industry continues to drill deeper, resulting in extreme operating temperatures for electronic systems. It is essential for electronic circuits and systems to be able to withstand extreme temperatures. The proposed power amplifier (PA) intends for a downhole communication system operating at an ambient temperature of 230 °C. The proposed PA is designed with Qorvo T2G6003028-FL GaN on SiC HEMT, which offers a high junction temperature. The proposed PA can operate reliably up to an ambient temperature of 230 °C with the operation frequency from 228 MHz to 263 MHz. At 230 °C, it achieves maximum output power of 1.66 W, the peak gain of 24 dB, peak PAE (power added efficiency) of 25%, OP1dB (output 1-db compression point) of 32 dBm, and OIP3 (output third intercept point) of 37.9 dBm..
Sintered Silver Die Attach with Extreme Thermal Stability for Extreme and Dynamic Environments
Authors: Khtatba Khalid , Paknejad Seyed Amir , Mansourian Ali , Mannan Samjid H. 
Published: July 2017

Abstract:
The surface oxidation of internal pore surfaces of nano-scale sintered silver has increased stability for high temperature applications. After treatment, high temperature storage at 400 °C has resulted in no changes to microstructure. By contrast, it is known that the microstructure of untreated pressure-less sintered silver continuously evolves at temperatures above 200 °C. Grain and pore growth occur in this temperature range for conventional sintered silver resulting in coarsening of the microstructure and increased susceptibility to fatigue. However, oxidation treatment of the internal pore surfaces has the effect of freezing the microstructure when the contact metallization is also silver or chemically inert. Oxidation prevents mass transfer by shutting down the fastest atomic migration route along the internal pore surfaces. Samples exhibited no change in microstructure either through continuous observation through glass, or after cross sectioning. The tested specimens under high temperature storage resisted grain growth for the whole duration of the tests of more than 600 h at 300 °C. The only detectable changes in microstructure occurred in a sparse number of isolated grains (1 in 7000 grains), presumably due to non-penetration of oxidising treatment into these closed pore spaces. It is hypothesized that even these can be prevented by minor changes to the sintering paste to slightly increase initial porosity. The oxidising treatment can be performed via many different routes, such as exposure to steam, or even by dipping in water for 10 min.
Time-efficient sintering processes to attach power devices using nanosilver dry film
Authors: Dai Jingru , Li Jianfeng , Agyakwa Pearl , Johnson Christopher Mark 
Published: July 2017

Abstract:
Pressure-assisted sintering processes to attach power devices using wet nanosilver pastes with time scales of minutes to a few hours have been widely reported. This paper presents our work on time-efficient sintering, using nanosilver dry film and an automatic die pick and place machine, resulting in process times of just a few seconds. The combined parameters of sintering temperature 250 °C, sintering pressure 10 MPa and sintering time 5 s were selected as the benchmark process to attach 2 mm × 2 mm × 0.5 mm dummy Si devices. Then the effects of either the sintering temperature (240 to 300 °C), time (1 to 9 s) or pressure (6 to 25 MPa) on the porosity and shear strength of the sintered joints were investigated with 3 groups and a total of 13 experimental trials. The average porosities of 24.6 to 46.2% and shear strengths of 26.1 to 47.7 MPa are comparable with and/or even better than those reported for sintered joints using wet nanosilver pastes. Their dependences on the sintering temperature, time and pressure are further fitted to equations similar to those describing the kinetics of sintering processes of powder compacts. The equations obtained can be used to not only reveal different mechanisms dominating the densification and bonding strength, but also anticipate the thermal-induced evolutions of microstructures of these rapidly sintered joints during future reliability tests and/or in service.
Design and fabrication of a power Si/SiC LDMOSFET for high temperature applications
Authors: Li F. , Gammon P.M. , Chan C.W. , Gity F. , Trajkovic T. , Kilchytska V. , Pathirana V. , Ben Ali K. , Flandre D. , Mawby P.A. , Gardner J.W. 
Published: July 2017

Abstract
Power Si/SiC LDMOSFET are being developed for the benefits of high temperature space and terrestrial harsh-environment applications. For the first time, high voltage devices are fabricated on a direct bonded Si/SiC substrate and characterised at room temperature. Peak field-effect channel mobility of the fabricated MOSFET reached ≈300 cm2/V.s and the avalanche breakdown was not observed up to 200 V, despite of a high leakage current in the device off-mode.
A Precision Data Acquisition and Control Platform for 200°C+ High Temperature Environments
Authors: Watson Jeff , Pachchigar Maithil , Bannatyne Ross , Merritt Clay , Conrad Christopher , Smollinger Glenn , Drack Earle 
Published: July 2017

Abstract
In recent years there has been an increasing selection of commercially available electronic components specified for very high temperature (200°C+) operation, driven by the needs of harsh-environment applications such as oil and gas exploration/production, aerospace, heavy industrial, and automotive. However, there remains a significant technical challenge to integrate these components into reliable, high performance systems. In this paper we present a complete reference platform implementation of a precision multichannel sensor data acquisition and control system rated to 200°C. The design offers a complete sensors-to-bits solution using a low power 16-bit, 600kSPS SAR ADC and an ARM® Cortex®-M0 based microcontroller. The signal chain is optimized for precision performance and accurate measurements while maintaining low power and a small footprint. The reference platform is available off the shelf, including hardware design files, processor firmware source code, and PC software for data logging and display, offering design engineers a rapid development tool for prototyping and a faster path to production for even complex harsh-environment applications, reducing design risk and evaluation time.
Evaluation of printed-circuit boards materials for high temperature operation
Authors: Aviño-Salvado Oriol , Sabbah Wissam , Buttay Cyril , Morel Hervé , Bevilacqua Pascal 
Published: July 2017

ABSTRACT
This article presents the long term (1000 h) behaviour of two printed-circuit board materials (Panasonic R1755V, a high-TG glass-epoxy composite and Arlon 85N, a polyimide-based laminate) stored at high temperature (190 °C). Tests are performed in air and in nitrogen atmospheres. Electrical and physical measurements are performed regularly (once per week).
Almost no degradation is observed for both materials, when stored in nitrogen. On the contrary, the board stored in air show the consequences of ageing. This is especially true for the glass-epoxy material, which becomes unusable after 2 weeks, because of large swelling.
The Tamessa project: a practical application of a 225°C multilayer PCB/SMT/COB system
Authors: Tremlett Piers R. 
Published: July 2017

Abstract
The Tamessa project has developed a high-temperature, multilayer, Printed Circuit Board and component assembly process that is capable of withstanding 225°C operating temperatures in a non-hermetic environment. This paper describes the practical application of this project's work to the electronic interface for a high temperature pressure sensor.
The PCB used in Tamessa has been made from novel materials and the Surface Mount Technology (SMT) component attach process is a solder-less process that uses an adhesive. Additionally, the project has developed and proved a Chip on Board (COB) system. The combination has enabled the development of a complete assembly system that has been shown to withstand temperature excursions up to 250°C in a non-hermetic environment. The successful application to a pressure sensor, designed to resist temperatures of 210°C, was a further test to demonstrate its practical capability in a real-life situation.
Effects of Bond Pad Thickness on Shear Strength of Copper Wire Bonds
Authors: Manoharan Subramani , Patel Chandradip , Hunter Stevan , McCluskey Patrick 
Published: July 2017

Abstract
Copper (Cu) wire bonding is now widely accepted as a replacement for gold (Au), however, its use in high reliability applications is limited due to early failures in high temperature and humid conditions. The Au to Cu wire transition is mainly driven by cost savings though there are other advantages to Cu such as better electrical and thermal conductivity, slower intermetallic compound (IMC) formation and reduced wire sweep during transfer molding. Some automotive, industrial and aerospace industries are still reluctant to adopt Cu wire bonded products due to perceived risks of wire and bond pad cracks, the potential for corrosion, and some lack of understanding about its reliability in harsh conditions.
A wire bond is considered good if destructive sampling qualification tests and periodic monitors pass for the batch. Tests include wire pull strength, wire bond shear, IMC coverage, and thickness of bond pad aluminum (Al) remaining beneath the bond. Nondestructive inspections also verify acceptable ball diameter and Al “splash”. This paper focuses on the bond shear test and its contribution to Cu ball bond reliability assessment, especially when changing Al bond pad thickness. A new revision of the JEDEC Wire Bond Shear Test Method, JESD22-B116B, has just been released, to include Cu wirebonds for the first time. It helps to clarify shear test failure modes for Cu ball bonds. However, there are still questions to be answered through research and experimentation, especially to learn the extent to which one may predict Cu ball bond reliability based on shear test results. Pad Al thickness is not considered in the current industry standards for shear test. Yet bond pad Al thickness varies widely among semiconductor products. This research is intended to contribute toward improved industry standards.
In this study, power and time bonding parameters along with bond pad thickness are studied for bond strength. Several wire bonds are created at different conditions, evaluated by optical microscope and SEM, IMC% coverage and bond shear strength. Similar bonding conditions are repeated for bond pads of 4um, 1um and 0.5um thickness.
A Comparison Between Solders & Transient Liquid Phase Sintered Interconnects in High Temperature Multi-Layer Ceramic Capacitors
Authors: Bultitude John , McConnell John , Jones Lonnie , Miller Galen , Magee Jim , Templeton Allen , Gurav Abhijit , Phillips Reggie 
Published: July 2017

Abstract
There is a long-established market for high temperature multi-layer ceramic capacitors (MLCC) that operate at 150°C and higher in down-hole oil & gas exploration, military and aerospace applications. To maximize the capacitance density and achieve a high degree of mechanical robustness, stacks and leaded form factors have been used with High Melting Point (HMP) Pb-containing solders as the preferred interconnects. However, Pb-containing solders are limited to temperatures below 300°C and are banned from many commercial and automotive applications with further legislation limiting their use planned in the future. Common Pb-free solders such as SAC 305 or SnSb alloys are in widespread use but their performance at prolonged exposures at 200°C is limited. Exposures to high reflow temperatures during assembly, especially successive reflow operations, can also compromise interconnect integrity. Higher temperature gold-containing solders are widely available but these are cost prohibitive and so are not viable for emerging high temperature electronics including higher volume, price sensitive Automotive and Power markets. The development of more energy efficient power converters and inverters based on Wide Band Gap (WBG) semiconductors is driving the adoption of higher temperature electronics in these markets since these operate at higher junction temperatures than traditional silicon. This has led to the development of non-solder interconnects based on sintered silver, nano-metal sintering and transient liquid phase sintering (TLPS) technologies capable of higher temperature performance than common solder based interconnects. The availability of discrete components, such as capacitors, that can operate under these conditions is a key barrier to the development and adoption of high temperature electronics. In this paper the key property differences between solders and TLPS interconnect technologies are compared in detail for MLCC interconnects. The development of a new range of nickel Base Metal Electrode C0G MLCC stacks rated for 200°C is described and performance compared to traditional Precious Metal Electrode (PME) stacks. Thermal cycling performance to 200°C of BME X7R stacks made with 10Sn/88Pb/2Ag solders are compared to similar stacks made with TLPS interconnects of Cu-Sn and In-Ag. The development of leadless stacks, a new bulk capacitance form factor enabled by TLPS technology, is described and their properties compared to traditional stacks.
Die-Attach Voiding Reduction in Gold Alloy Solder Preforms
Authors: Leavitt Bernard , Mackie Andy C. 
Published: July 2017

Abstract
The need for high-temperature solders is growing as RF and power semiconductor devices continue to get smaller, with power density increasing both as a consequence of the shrink and as a result of increased power ratings. AuSn20 eutectic solder (Indalloy®182) has been the workhorse for high-temperature, high-reliability, small die-attach applications for many years; however, as junction temperatures (Tj) increase, the gold-tin eutectic is beginning to reach its limit of utility. Higher temperatures cause increased thermal fatigue, and even delamination is seen at the solder joints.
The next option for RF and power semiconductor manufacturers needing these higher temperatures is either AuGe12 (Indalloy®183) or AuSi3.2 (Indalloy®184) eutectic alloy (see Table I).Table 1.Key properties of Au-based eutectic alloys.
Over the years, many customers have tried AuGe12 and the feedback has been that the alloy has poor solderability, which manifests as large voids in the bond. Voids are poor conductors of heat, which create hot spots, and are the primary cause of premature failures.
Recursos livres, livros fechados: uma análise da dimensão interativa dos objetos educacionais digitais no ensino de Sociologia
Authors: Bueno Zuleika De Paula , Carniel Fagner 
Published: July 2017

DOI: http://dx.doi.org/10.5007/2175-7984.2015v14n31p132Este artigo pretende discutir a dimensão interativa dos livros didáticos digitais aprovados peloPrograma Nacional do Livro Didático (PNLD). A investigação proposta tomou como referênciaas obras de Sociologia avaliadas pelo programa em 2015. O objetivo é analisar tais materiaisconsiderando suas potencialidades e seus limites de uso no Ensino Médio brasileiro. Para tanto,consideramos os pressupostos teóricos oferecidos pela bibliografia recente sobre mídias digitaise destacamos as formas emergentes de interação com o conhecimento socialmente produzido e disponibilizado na web. Por fim, evidenciamos o choque entre lógicas fechadas, restritas e protegidas, que organizam os atuais livros didáticos digitais disponibilizados aos colégios públicos do país, e os usos de softwares livres de edição que estão sendo disseminados nos formatos de recursos educacionais abertos.
Destinos, Escolhas e a Democratização do Ensino Superior
Authors: Barbosa Maria Ligia De Oliveira 
Published: July 2017

DOI: http://dx.doi.org/10.5007/2175-7984.2015v14n31p256Este artigo analisa algumas das diversas políticas (tanto governamentais quanto institucionais) que visam a assegurar o acesso e a permanência dos estudantes até a conclusão dos cursos no sistema brasileiro de ensino superior. Trata-se de uma tentativa de avançar na discussão sobre qual seria uma democratização possível para esse sistema. O artigo busca verificar se, apesar da manutenção dos padrões de desigualdade estrutural, de prestígio e renda, seria possível encontrar políticas que se contraponham a essa tendência. Foram analisadas as políticas de cotas raciais e sociais, o Reuni e o ProUni, bem como o programa de interiorização da Universidade Federal Fluminense (UFF) e de estágios e bolsas na Pontifícia Universidade Católica de Minas Gerais (PUC-Minas). Foram utilizadas pesquisas feitas por pesquisadores do LAPES/UFRJ/CNPq. O material analisado permite confirmar a existência de ações e políticas que criam probabilidades efetivas de que Escolhas dos indivíduos e grupos possam prevalecer sobre os Destinos socialmente desenhados para eles.
Ensino e docência: desafios para a formação e atuação de professores de Sociologia/Ciências Sociais
Authors: De Araújo Souza Jordânia , Marinho Noélia Nunes , Gaudencio Júlio Cezar 
Published: July 2017

DOI: http://dx.doi.org/10.5007/2175-7984.2015v14n31p63O objetivo do presente artigo é problematizar questões em torno dos desafios postos com oretorno e a institucionalização do ensino de Sociologia/Ciências Sociais na Educação Básica, pormeio da Lei nº 11.684/2008. Tais desafios são vivenciados tanto nos Cursos de Licenciatura emCiências Sociais quanto nas salas de aula da disciplina de Sociologia no Ensino Médio. Neste sentido, a ideia é ponderar questões em torno da formação docente, chamando atenção para o abismo ainda existente entre a formação e a atuação dos professores de Sociologia/Ciências Sociais tendo como pano de fundo a formação que vem sendo desenvolvida pela Universidade Federal de Alagoas no Curso de Licenciatura em Ciências Sociais presencial do Instituto de Ciências Sociais.
Nacionalismo e diversidade: do Programa “Esquenta”, da Rede Globo, à cerimônia de abertura das Olimpíadas do Rio 2016
Authors: Da Mota Rocha Maria Eduarda 
Published: July 2017

http://dx.doi.org/10.5007/2175-7984.2017v16n35p159O artigo propõe uma análise das formas de articulação entre o nacionalismo e a diversidade na cultura brasileira atual, tomando como objetos o programa Esquenta, da Rede Globo, e a cerimônia de abertura das Olimpíadas Rio 2016. Eles têm em comum uma alternância entre momentos de unidade e fragmentação que indicam os impasses e as saídas encontradas para falar em “Brasil” em um contexto político e cultural de crítica à assimilação do “outro” pelo discurso dominante. A participação de Regina Casé na cerimônia é muito mais do que casual. Ao mesmo tempo em que é vista como a “embaixadora da periferia” na TV, ela é um elo importante na rede de artistas e intelectuais que emergiram na cena cultural brasileira a partir dos anos de 1980, no teatro, no vídeo, no cinema e na TV. Os diretores da cerimônia de abertura também fazem parte da primeira geração de artistas e intelectuais formados após a consolidação de uma indústria cultural no Brasil, o que repercutiu no seu percurso formativo na medida em que a TV e a publicidade foram importantes espaços de socialização profissional para muitos dessa geração. Da mesma forma, a partir de 1980, respiraram os ares de crítica ao nacionalismo por sua associação ao Regime Militar e de crescente valorização da “diversidade”. Nessa chave analítica, partiremos do Núcleo Guel Arraes (NGA), da Rede Globo, que foi um ponto de agregação para muitos artistas dessa geração,até chegar ao programa Esquenta no qual o projeto estético-político de visibilidade da “periferia” é a principal forma de expressão da “diversidade”. Depois, identificaremos ecos desse projeto na cerimônia de abertura, tentando mostrar que ela esboçou uma solução semelhante para a difícil conciliação entre o problema da identidade nacional e o valor da diversidade.
Insegurança, desperdício e ajuda alimentar na Europa do Século XXI
Authors: Filgueiras Cristina Almeida Cunha 
Published: July 2017

http://dx.doi.org/10.5007/2175-7984.2017v16n35p432O artigo examina aspectos sociológicos e políticos da insegurança alimentar e da ajuda em alimentos destinada a milhões de pessoas na Europa. É abordada, inicialmente, a situação de insegurança alimentar associada à pobreza. Em seguida, menciona-se que o grave problema do desperdício de alimentos, o qual tem exigido cada vez mais atenção de governos, organismos internacionais e sociedade, e não pode ser considerado atualmente como causa da falta de acesso à alimentação. Posteriormente, analisa-se o principal programa europeu de ajuda, dando especial atenção ao seu funcionamento na França.
Da religiosidade: entre místicos, bestas e soberanos
Authors: Alonso Rafael 
Published: July 2017

http://dx.doi.org/10.5007/2176-8552.2016n20p25Levando em conta o que aqui se chama “crise da religiosidade”, este ensaio se propõe a discutir, em contraposição crítica que a leitura do texto tende a tornar evidente, as respostas a essa crise oferecidas por Georges Bataille (“experiência interior”, “experiência do sagrado”) e Giorgio Agamben (“altíssima pobreza”). O que motiva a contraposição é o juízo de Agamben a respeito de Bataille, antes já enunciado por Sartre: o de que Bataille é um místico. Para colocar em prática essa operação, este ensaio recorre às contribuições de Jean-Luc Nancy (existência “insacrificável”), Jacques Derrida (o discurso político como fábula e a crítica feroz a Agamben em “A besta e o soberano”) e Vilém Flusser, base teórica que atravessa todo ensaio e que, com o conceito de “instrumento”, mas também a partir de outras elaborações teóricas, permite questionar a ideia de um mundo a ser “profanado”.