bluuebunny/crossref_metadata_2025 huggingface dataset:
Perfil de desempenho dos estudantes de Educação Física na prova do Enade nas questões sobre Saúde da Criança e do Adolescente
Authors: Rabelo Iriadelia Soraya Ribeiro , Medeiros Filho Antonio Evanildo Cardoso de , Gomes Régia Carla Nogueira Torres
Published: December 2020

A avaliação está presente em todos os momentos da vida. Na educação escolarizada, tem como finalidade estabelecer diagnósticos para fins de melhoria do processo educativo. O Exame Nacional de Desempenho dos Estudantes, parte integrante do Sistema Nacional de Avaliação da Educação Superior, tem como objetivo geral avaliar o desempenho dos estudantes em relação aos conteúdos programáticos previstos nas diretrizes curriculares, às habilidades e competências para atuação profissional e aos conhecimentos sobre a realidade brasileira e mundial, bem como sobre outras áreas do conhecimento. O objetivo do estudo foi traçar o perfil de desempenho dos estudantes que realizaram a prova o exame nas questões sobre saúde da criança e do adolescente. Obtivemos como resultados que as médias dos estudantes da Universidade Estadual do Ceará, nas provas de 2007, 2011, 2014 e 2017 são maiores do que as médias do Ceará e do Brasil nos itens analisados.  Em relação as regiões, destacam com maiores médias as regiões Nordeste e Sul. O estudo pode contribuir para a organização curricular dos cursos de Educação Física, bem como contribuir com o aprimoramento da formação dos acadêmicos em relação aos temas da saúde da criança e do adolescente.
A aula em avaliação: uma análise à luz da pedagogia histórico-crítica
Authors: Moreira Marisa de Souza Cunha , Osti Andréia
Published: December 2020

Este texto busca analisar a aula enquanto um componente indispensável e que requer avaliação como um dos aspectos para qualificar o ensino escolar na educação básica. Trata-se de um ensaio teórico que analisa qualitativamente o objeto mencionado à luz da pedagogia histórico-crítica e também de pressupostos da psicologia histórico-cultural que possibilitam observar o fenômeno tendo como premissas teóricas promover o máximo desenvolvimento das potencialidades humanas, as quais entendem que a educação escolar pode contribuir efetivamente, por meio do ensino intencional, sistematizado, uma vez que compreende a escola como agente de transformação dos seres humanos, principalmente os filhos da classe trabalhadora. Nesse sentido, discutir elementos centrais e as potencialidades que uma aula possui tornam-se centrais na discussão apresentada.
Raça/etnia e o desempenho dos estudantes de educação física no Enade
Authors: Silva Lucas Souza , Silva Francisca Feitosa da , Medeiros Filho Antonio Evanildo Cardoso de
Published: December 2020

O estudo teve como objetivo analisar o desempenho dos estudantes de licenciatura em Educação Física no Exame Nacional de Desempenho de Estudantes (ENADE) 2017 de acordo com a raça/etnia. Participaram do estudo 15.400 indivíduos, com média de idade 26,52 (± 6,43). Foram utilizados os microdados do Instituto Nacional de Estudos e Pesquisas Anísio Teixeira que tiveram suas respostas validadas e posteriormente foram realizadas estatísticas descritivas simples. Evidenciamos baixo desempenho em relação aos estudantes identificados como negros e indígenas, pertencendo os melhores desempenhos aos estudantes autodeclarados brancos e amarelos.
Eficiência e produtividade: dilemas docentes
Authors: Soares Erineuda do Amaral , Werle Flávia Obino Corrêa
Published: December 2020

Pretende-se, neste trabalho, discutir sobre uma das estratégias usadas por gestores escolares diante das exigências por resultados nas avaliações em larga escala, especialmente para professores do segundo ano do Ensino Fundamental. Trata-se de uma reflexão que emerge a posteriori da recolha dos dados de um estudo de casos múltiplos acerca do Sistema Permanente de Avaliação da Educação Básica do Ceará-Alfabetização (SPAECE-Alfa), realizado em quatro escolas municipais de Fortaleza. A coleta dos dados ocorreu por meio de entrevistas semiestruturadas realizadas com quatro gestores escolares. As análises indicam que uma das estratégias efetivadas nas escolas para melhorar o rendimento dos alunos avaliados é a transferência de professores considerados “inaptos” como alfabetizadores para turmas não avaliadas. No entanto, fazem-se necessários outros estudos para que seja verificada a eficácia dessa estratégia nos indicadores educacionais, bem como, seja analisado seu impacto nas ações e subjetividades desses profissionais.
Nitrate Reducing and Denitrifying Bacteria in Oil/Brine Contaminated Soils
Authors: AbuBakr Samer
Published: December 2020

Soil microorganisms are a fundamental part of biogeochemical cycling of nitrogen. Denitrification is an important component of nitrogen cycling, in which some microorganisms (e.g. denitrifying bacteria) use nitrate or nitrite as alternative electron acceptors. In fact, several studies have focused on various aspects of nitrogen cycling. Philippot et al. (2009) linked the distribution of the fraction of bacteria with the genetic capacity to reduce N2O to N2 to areas with low potential N2O emissions in a pasture. In addition, it was shown that a map of denitrification activity across a whole farm was reflected by maps displaying the community size and structure of a specific fraction of the denitrifyers at the site (Enwall et al., 2010). Since denitrification releases mineralized nitrogen in the soil ecosystem to the atmosphere, the balance between denitrification and N-fixation can determine the biologically available nitrogen for soils. Denitrification could be affected by soil ecosystem contaminants such as crude oil and brine as they may alter the abundance and species composition of denitrifying bacteria in predictable ways. For example, γ-Proteobacteria are known to increase in crude-oil contaminated sites and in fact, a wide diversity of γ-Proteobacteria including Pseudomonas and Vibrio species were shown to degrade hydrocarbons under nitrate reducing (NR) conditions (Rockne et al., 2000). Other studies showed that strains for several genera of γ-Proteobacteria have the ability to denitrify. In fact, it was shown that nitrate and nitrite reduction rates were increasingly inhibited at increasing NaCl concentrations when comparing treatment of fishery wastewaters. Bacterial diversity in brine-contaminated sites is expected to be less because of selection for salt-tolerant genera such as Bacillus and Pseudomonas.
Investigation of Bunch Cut at Different Times After Pollination and Flower Position in the Spikelet in Date Palm 'Sukkary' Variety
Authors: ElJiati Abdelazize
Published: December 2020

As many studies on other crops showed an acropetal decline of fruit-set and fruit size in the inflorescence, this paper investigates the effect of flower position in spikelets in the '˜Sukkary' variety of date palm on fruit-set and final fruit weight. Also studied was the best time to apply strand-cut (bunch cut) as an alternative to hand thinning, to increase final fruit weight. Hand thinning is a labor cost operation and worker productivity operation is one adult tree per day maximum. To study fruit-set in relation to fruit position, three types of pollen were used to pollinate female trees: new pollen harvested in March 2018, pollen stored for one year at room temperature (25-35° C), and pollen stored for two years at room temperature. Four weeks after pollination, fruits aborted and those non-aborted in every bunch were counted. Recording was done in every spikelet from proximal to distal. To study the effect of fruit position in spikelet on fruit weight, fresh pollen was used to pollinate 'Sukkary' females. Every two days, fruit weight was measured from pollination to harvest, and fruit growth pattern was drawn. An analysis of variance (ANOVA) was carried out for the final fruit weight in every spikelet part. This investigation showed no pattern in fruit-set or in final fruit weight when using new pollen. When pollinated with old pollen that was one and two years old, the proximal '˜Sukkary' flowers of the spikelets showed less fruit-set compared to those of the middle and distal part. This basipetal decline is explained by low viability of old pollen, combined with the basipetal opening of the spathes in date palm...
An Analytical Evaluation of ESP Textbook for Engineering Students in Sudanese Universities A Case Study of Sudan International University SIU English Language Course, C
Authors: Wdidi Osama
Published: December 2020

The current study is conducted to evaluate the English language textbook used for university students who specialized in engineering; the case study of this research is the textbook which is indorsed to teach English to the university students of engineering college at Sudan International University. The main objective of this evaluation is to analyze the textbook to recognize whether it suits the engineering students. The adopted method for this study was descriptive analytical method. The researcher used the questionnaire, (an Arabic version) for a sample of (90) engineering college students. The findings of the study have shown that an overwhelming majority of the students agreed that the layout of the textbook is perfect and its design is suitable. Besides, they acknowledged that textbook is quite satisfactory in terms of its activities. Based on the above findings, the researcher comes to the conclusion that the textbook which is taught in this university, with all these positive views is definitely a favorable and useful textbook for the engineering students and at Sudan International University.
Making seafood accessible to low-income and nutritionally vulnerable populations on the U.S. West Coast
Authors: Koehn J. , Quinn Emilee , Otten Jennifer , Allison Edward , Anderson Christopher
Published: December 2020

Along the U.S. West Coast, sustainable manage­ment has rebuilt fish stocks, providing an oppor­tunity to supply nutrient-rich food to adjacent coastal communities where food insecurity and diet-based diseases are common. However, the market has not successfully supplied locally sourced seafood to nutritionally vulnerable people. Rather, a few organizations make this connection on a limited scale. We used a “positive deviant” approach to learn how these organizations’ efforts developed, how they overcame challenges, and what conditions enabled their interventions. We found that organizations in these positive deviant cases provided fish from a wide variety of species and sources, and distributed them through different channels to a diversity of end consumers. A key factor facilitating success was the ability to negotiate a price point that was both profitable and reasonable for organizations supplying nutritionally vulnerable or low-income consumers. Further­more, securing access to grants overcame initial costs of establishing new supply channels. All cases highlighted the importance of individual cham­pi­ons who encouraged development and cultural connections between the initiative and the nearby community. Organizations overcame key chal­lenges by establishing regulations governing these new channels and either using partnerships or vertically integrating to reduce costs associated with processing and transport. Oftentimes training and education were also critical to instruct workers on how to process unfamiliar fish and to increase consumer awareness of local fish and how to pre­pare them. These lessons illuminate pathways to improve the contribution of local seafood to the healthy food system.
EVOLUTION OF INVISIBLE Au IN ARSENIAN PYRITE IN CARLIN-TYPE Au DEPOSITS
Authors: Liang Qing-Lin , Xie Zhuojun , Song Xie-Yan , Wirth Richard , Xia Yong , Cline Jean
Published: December 2020

A significant characteristic distinguishing Carlin-type Au deposits from other Au deposits is the abundance of invisible Au in arsenian pyrite. Gold occurs primarily as ionic Au1+ in arsenian pyrite and is unstable during subsequent thermal events. In this study, we used the focused ion beam combined with scanning electron microscope (FIB-SEM) techniques, and a transmission electron microscope (TEM) to examine invisible Au and how it evolved through later geologic events that eventually led to the formation of Au nanoparticles. FIB-SEM techniques were used to prepare site-specific TEM foils from four Carlin-type gold deposits, including Getchell and Cortez Hills, Nevada, USA, and Shuiyindong and Jinfeng, Guizhou Province, China. These samples were analyzed to quantify ore pyrite chemistry and evaluate textures at the nanometer scale.

In 17 examined TEM foils, we observed widespread Au-rich domains in high-grade Au arsenian pyrites from the Getchell and Cortez Hills Au deposits and the Jinfeng deposit but only 10 Au-bearing nanoparticles, ~10 to 20 nm in diameter. The Au-rich domains exhibit Au (Sb), (Tl), (Hg), and (Cu) peaks in the energy dispersive X-ray (EDX) spectrum without the presence of recognizable nanoparticles. This confirms that Au is invisible even at a nanometer scale and is most likely present in the crystal structure of arsenian pyrite. Stacking faults and nanometer-sized fluid inclusions were commonly observed in Au-bearing arsenian pyrite from the four deposits, implying rapid crystallization. Moreover, unlike the coarsely crystalline arsenian pyrite from Guizhou Carlin-type Au deposits, arsenian pyrite from Carlin-type deposits in Nevada consists of fine-grained polycrystalline aggregates, further implying rapid crystallization. Additionally, curved dislocations were commonly pinned by solid inclusions, reflecting a former annealing process.

Combining nanoscale textures with geologic information previously reported for Carlin-type deposits, invisible ionic Au was initially incorporated into the crystal structure of arsenian pyrite during rapid precipitation. Subsequent post-ore magmatic events in both districts initiated the annealing of the ionic Au-bearing arsenian pyrite, leading to the redistribution of trace elements and formation of Au-bearing nanoparticles in the arsenian pyrite. The presence of predominantly ionically bonded Au in arsenian pyrite confirms that ore fluids were not saturated in Au when Au-bearing arsenian pyrite formed, as previously reported for Carlin-type deposits. Ionic Au that was scavenged from an undersaturated ore fluid and incorporated into the arsenian pyrite crystal structure formed the giant Carlin-type Au deposits.
Quantitative Mineral Mapping of Drill Core Surfaces I: A Method for µXRF Mineral Calculation and Mapping of Hydrothermally Altered, Fine-Grained Sedimentary Rocks from a Carlin-Type Gold Deposit
Authors: Barker Rocky D. , Barker Shaun L.L. , Wilson Sasha , Stock Elizabeth D.
Published: December 2020

Mineral distributions can be determined in drill core samples from a Carlin-type gold deposit, using micro-X-ray fluorescence (µXRF) raster data. Micro-XRF data were collected using a Bruker Tornado µXRF scanner on split drill core samples (~25 × 8 cm) with data collected at a spatial resolution of ~100 µm. Bruker AMICS software was used to identify mineral species from µXRF raster data, which revealed that many individual sample spots were mineral mixtures due to the fine-grained nature of the samples. In order to estimate the mineral abundances in each pixel, we used a linear programming (LP) approach on quantified µXRF data. Quantification of µXRF spectra was completed using a fundamental parameters (FP) standardless approach. Results of the FP method compared to standardized wavelength dispersive spectrometry (WDS)-XRF of the same samples showed that the FP method for quantification of µXRF spectra was precise (R2 values of 0.98–0.97) although the FP method gave a slight overestimate of Fe and K and an underestimate of Mg abundance. Accuracy of the quantified µXRF chemistry results was further improved by using the WDS-XRF data as a calibration correction before calculating mineralogy using LP. The LP mineral abundance predictions were compared to Rietveld refinement results using X-ray diffraction (XRD) patterns collected from powders of the same drill core samples. The root mean square error (RMSE) for LP-predicted mineralogy compared to quantitative XRD results ranges from 0.91 to 7.15% for quartz, potassium feldspar, pyrite, kaolinite, calcite, dolomite, and illite.

The approaches outlined here demonstrates that µXRF maps can be used to determine mineralogy, mineral abundances, and mineralogical textures not visible with the naked eye from fine-grained sedimentary rocks associated with Carlin-type Au deposits. This approach is transferable to any ore deposit, but particularly useful in sedimentary-hosted ore deposits where ore and gangue minerals are often fine grained and difficult to distinguish in hand specimen.
Introducción: perspectivas críticas sobre el ELE como industria y mercado
Authors: Bruzos Alberto
Published: December 2020

Introducción
La irrupción del “empresario de sí mismo” en los libros de texto de ELE
Authors: Bori Pau
Published: December 2020

El artículo explora la penetración de la racionalidad neoliberal en materiales didácticos de español como lengua extranjera. Muestra como los libros de texto actuales priorizan y promueven el modelo antropológico neoliberal, el “empresario de sí mismo”, en sus representaciones de la realidad y en las actividades para los aprendices. Esa visión del mundo contrasta con la de una popular colección de libros de texto de los setenta, que mostraba la división en clases sociales y el conflicto existente entre ellas. Cierran el artículo las implicaciones del estudio y recomendaciones para docentes interesados en adoptar una perspectiva crítica en el aula.
El taller intergeneracional de huerto como propuesta de intervención para el alumnado con necesidades educativas especiales
Authors: Navarro Soria Ignasi , Hernández Gandía Virtudes
Published: December 2020

En la actualidad, el alumnado con necesidades educativas especiales de los centros de educación especial requiere apoyos y medidas de alta intensidad e individualización para mejorar su desarrollo en las diferentes áreas de intervención y asegurar su máxima participación y vinculación con el entorno. Debido en parte a su historial de fracasos, los niños y niñas pueden presentar baja autoestima y autoconcepto, así como una limitación en las relaciones sociales, con tendencia al aislamiento. En este trabajo de investigación se plantea la realización de un taller intergeneracional de huerto entre el CEE APADIS y el Centro de Día de Alzheimer (Villena), como propuesta de intervención educativa para incrementar la autoestima, el autoconcepto, el bienestar emocional y las habilidades relacionales de los menores. Dentro de la investigación realizada se diferenciaron dos partes: evaluación pretest y postest a la realización del proyecto y valoración de las sesiones individuales del mismo. Los instrumentos empleados en la recogida de información fueron escalas fiables y validadas científicamente (algunas de ellas adaptadas) y también cuestionarios ad hoc. Una vez realizadas las sesiones de trabajo y analizados los resultados, se ha podido comprobar una mejora generalizada en todas las variables estudiadas, que demostraría la eficacia de los programas intergeneracionales como estrategia metodológica.
The Expression of CD64 and CD11b Neutrophils in Neonatal Necrotizing Enterocolitis
Authors: Zhang Junping , Wang Xi , Lei Guofeng , Zhang Jiye , Wang Xiaobing , Xie Aimin
Published: December 2020

Objectives: To investigate the expression of CD64 and CD11b neutrophils in neonates with necrotizing enterocolitis (NEC) and to evaluate the diagnostic value of CD64 and CD11b in identifying NEC in neonates. Methods: A total of 138 newborns, admitted to our neonatal intensive care unit from October 2018 to March 2020, were recruited in this study. The subjects were divided into the NEC and control groups, according to the method of case-control. The expression of CD64, CD11b, and C-reactive protein (CRP) was measured in the peripheral blood, the sensitivity and specificity of each index in diagnosing NEC were compared, and their diagnostic value was examined. Results: The corrected gestational age of the NEC and control groups was 32.29 ± 1.85 and 33.24 ± 1.98 weeks, respectively. The mean birth weight of the two groups was 1654 ± 373 and 1746 ± 400 g, respectively. Also, the mean age at sampling was 11.6 ± 3.11 and 11.7 ± 3.14 days in the NEC and control groups, respectively. Gender, corrected gestational age, mean birth weight, and sampling age were not significantly different between the groups (P > 0.05). The CD64 and CD11b expression levels were higher in the NEC group, compared to the control group (P < 0.01). Comparison of the NEC group by stage showed that the CD64 and CD11b indices were the highest in stage III, followed by stage II and stage I (P = 0.01). However, both indices showed a downward trend during the recovery period (P < 0.01). A CD64 level ≥ 0.71, a CD11b level of 1.94, and a CRP level ≥ 7.38 were considered as the best diagnostic criteria. The highest exponential sensitivity (82.7%) was attributed to the CD64 index, followed by CD11b (50.8%) and CRP (39.1%). The highest sensitivity (89%) was obtained by a combination of two indices (one positive index); also, when both indices were positive, the highest specificity (87%) was reported. The sensitivity of combined indices for NEC diagnosis in stage I, II and III were 84.4%, 95.7%, and 92.9%, respectively. Conclusions: The expression levels of CD64 and CD11b neutrophils in neonatal NEC increased and was associated with the severity of NEC. Monitoring of changes in the two indices had a clinical value in the diagnosis of NEC. In conclusion, the combined use of these two indices can be more valuable in the diagnosis of neonatal NEC.
The Constitution of the Human Person as Discovery and Awakening
Authors: Betschart Christof ,   Philosophy Documentation Center
Published: December 2020

Scholars strive, in their treatment of Stein’s work, to express both a phenomenological concept of the human person, characterized by conscious and free spiritual activity, and a metaphysical concept of the person, seen as an individual essence unfolding throughout life. In Stein’s work, the two concepts are not simply juxtaposed, nor is there a shift from one to the other. Stein integrates her phenomenological research into a metaphysical framework. In the present contribution, I endeavor to show that Stein’s interpretation of Husserl’s concept of constitution focuses on the question of whether this constitution is to be understood realistically or idealistically and on the question of the constituting subject. I shall argue that Stein’s interpretation of constitution is closely linked to the lived experience she calls already in her early writings “self-discovery” and “awakening.”
Personalized Medicine by Design
Authors: Kaplan Saul
Published: December 2020

Sometimes tweaks aren’t enough. Sometimes nothing short of reinventing yourself, your organization, or your community is called for. Today feels like one of those times. If anything is certain about the new millennium it’s the pace of change. New technology relentlessly hurdles into our lives. Ideas and practices travel around the world at internet speed. Social media enables individuals to self-organize and reorganize in ways unimaginable in the 20th century.  We also live in anxious times marked by a pandemic and economic uncertainty but one thing is clear, relevancy is more fleeting than ever. How to stay relevant in a changing and uncertain world is one of the most important questions of our time.
Solving Hard Problems with AI: Dramatically Accelerating Drug Discovery Through A Unique Public-Private Partnership
Authors: Baldoni John , Begoli Edmon , Kusnezov Dimitri , MacWilliams John
Published: December 2020

Dramatic disruptions in technologies can result in the creation of new markets, the emergence of new paradigms, and the displacement of entrenched approaches and business models. This can be especially pronounced when multiple technologies converge to create something new. Today, artificial intelligence (“AI”) is acting as an accelerant for such technology transformations. Still, the scope and depth of its impact will depend in part on our ability to address challenging problems that are surfacing without solutions. Industries will pursue AI for their corporate missions and to create shareholder value.  But the timescales and applications can be incongruent with important public needs and with the longer research horizons required to make real progress. Public-Private partnerships are an important mechanism for tackling these rapidly emerging new, complex, challenging problems. This paper examines our experience gained by creating a unique public-private partnership to apply AI to one example of a hard problem that is particularly timely today-- dramatically accelerating drug discovery.
Netflix and the design of the audience
Authors: Matthew Jeremy Ryan
Published: December 2020

This paper explores how audiences engage with Netflix as an intermediary in their digital lives, and how Netflix, as it is designed, creates a highly constrained system for its users. The paper is based on a study of observed use and discussions with Netflix users. It explores the limitations that are designed into Netflix as a digital media platform, and how Netflix users engage with this system that obscures rather than clarifies the contents of the platform. The paper discusses examples of frustration, confusion, and misdirection that Netflix, as a heavily constrained system, cultivates. It argues that the thoughts, feelings, and desires of audiences are not reflected in the data-driven design of digital media platforms like Netflix. Instead, data are used by Netflix to design a personalized environment that acts as a set of blinders which constrain the agency of the audience through an interface designed to dazzle and disorient Netflix users.
Automated Media, Routledge, 2020
Authors: Svensson Jakob
Published: December 2020

Book review
Government Ecology and the Indigenous Religion of the Suku Anak Dalam: Intersubjective Relations in Forest Conservation in Jambi, Indonesia
Authors:   Department of Governmental Studies, UIN Sulthan Thaha Saifuddin, Jl. Lintas Jambi-Muara Bulian KM.16,  Simpang Sei Duren, Jambi, Indonesia 36361, Najib K
Published: December 2020

Integrating customary-religious values of an indigenous tribe "Suku Anak Dalam” (SAD) and state zoning system in Bukit Duabelas National Park (TNBD), Jambi, Indonesia is a configuration of an intersubjective relationship between government ecology and the religion of indigenous SAD in forest conservation that has not been studied by previous researchers. Hence, this article discusses that intersubjective relationship practice in preserving, maintaining, and protecting sustainable forest by assimilating the SAD's customary-religious values and the state zoning system. Moreover, this article also complements the shortcomings of previous researchers who believe that SAD's cosmology is animistic and proves that the TNBD zoning system's implementation as a cause of the SAD conflict. After conducting the interviews and the observations supported by relevant literature sources, this article shows that the SAD believes that the cosmos is not only inhabited by humans, but there are nonhuman beings such as animals and Badewo who are perceived as a human in which they are believed as social actors in forest conservation. SAD and nonhuman beings live together and contribute to each other and have a mutual relationship to life sustainability in the forest or so-called indigenous religion. Besides, the article also found that the TNBD zoning system is not the primary cause of the SAD conflict, rather the dynamics process in integrating state zoning and indigenous custom-religious spaces between the TNBD offices and the SAD.
The Lie point symmetry-preserving difference scheme of holonomic constrained mechanical systems
Authors: Zhang Hong-Bin  , Lü Hong-Sheng  , Gu Shu-Long  ,   (1)Department of Mathematics, Chaohu College, Chaohu 238000,China; (2)Department of Physics, Chaohu College, Chaohu 238000,China
Published: December 2020

In this paper a Lie point symmetry- preserving difference schemes approximating holonomic constrained mechanical systems is presented. The procedure is as follows: Firstly we find the Lie point symmetry groups of the original equation, and prolong them to three points of the lattice. Secondly the discrete invariants are obtained by solving discrete characteristic equations, then the invariant difference scheme is constructed by using these discrete invariants; and this invariants difference scheme will give the original equation under the continuous limit. Finally an example is presented to illustrate the applications of the result.
Effect of Hubble parameter on the orbit of light ray and radar echo delay in Robertson-McVittie spacetime
Authors: Gong Yan-Xiang  , Li Feng  ,   College of Physics and Electronic Engineering, Taishan University, Taian 271021, China
Published: December 2020

In this paper, the effect of Hubble parameter on the propagation of electromagnetic wave in Robertson-McVittie spacetime is discussed by using the post-Newtonian approximation method. To the bending test of light ray, the deflection angle caused by Hubble parameter H0 is calculated to its maximum amendatory term. Besides, the effects of finite distances of light source and receiver (d1 and d2 ) on deflection angle are also considered in this work. To the radar echo delay test, the maximum amendatory term to the formulae, induced by Hubble parameter, is given. The paper focuss on the study of influence of cosmological expansion on the propagation of electromagnetic wave. The work can be checked in the current high-precision gravity experiments in space and provides a theoretical basis for these experiments.
Synchronization in a threshold coupled chaotic neuronal map
Authors: He Guo-Guang  , Zhu Ping  , Chen Hong-Ping  , Xie Xiao-Ping  ,   Department of Physics,Zhejiang University,Hangzhou 310027,China
Published: December 2020

We used a threshold controlling method to control chaos of chaotic neuron and constructed a threshold coupled chaotic neuronal map. The synchronization of the threshold coupled chaotic neuronal map was investigated. Simulation results show that the value of threshold determines the temporal period of outputs of the threshold coupled chaotic neuronal map. The spatial behavior of outputs of the threshold coupled chaotic neuronal map is determined by a relaxation time. A cluster character exists in the threshold coupled chaotic neuronal map. The synchronization of outputs of the threshold coupled chaotic neuronal map is achieved if the relaxation time is big enough.
Theoretical study of inelastic current in a single molecule attached to electrode system
Authors: Zhang Yuan  , Wang Lu-Xia  ,   Department of Physics, University of Science and Technology Beijing, Beijing 100083, China
Published: December 2020

Considering the effect of molecular vibrational levels, inelastic currents through the "metal/single molecule/metal" in the frame of normal vibrational mode are studied. The results show that the Franck-Condon blockage is strongly dependent on the stable energy configuration of molecule in the charge transmission, thus the relation between stationary state and Franck-Condon blockage and the relations of intra molecular vibrational redistribution as well as the relative position of molecule and electrodes to the current-voltage character of the stationary molecule state are further studied theoretically.
Paraxial electron optics and its spatial-temporal aberrations for a bi-electrode concentric spherical system with electrostatic focusing
Authors: Zhang Zhi-Quan  , Zhang Yi-Fei  , Zhou Li-Wei  , Gong Hui  ,   (1)Department of Control Engineering, Institute of Armored Force Engineering, Beijing 100072, China; (2)School of Photonics, Beijing Institute of Technology, Beijing 100081, China
Published: December 2020

In this paper, we use the paraxial equations to study the spatial-temporal trajectories and their aberrations for a bi-electrode concentric spherical system with electrostatic focusing. In the present paper, starting from the paraxial ray equation and the paraxial motion equation, the paraxial spatial-temporal trajectory of moving electron emitted from the photocathode is obtained for a bi-electrode concentric spherical system with electrostatic focusing. The paraxial static and dynamic electron optics, as well as the paraxial spatial-temporal aberrations in this system are then discussed, the general regularity of imaging in paraxial optical system has been explored. The paraxial spatial aberrations, as well as the paraxial temporal aberrations with different orders, have been defined and deduced. Thus we get same conclusions about paraxial spatial and temporal aberrations as it has been given in paper[1], and it completely shows that the paraxial spatial-temporal aberrations can be investigated directly from the paraxial ray equation and paraxial motion equation.
Investigation of characteristic microstructures of wild ginseng by X-ray phase contrast microscopy
Authors: Chen Can  , Du Guo-Hao  , Xiao Ti-Qiao  , Guo Rong-Yi  , Ren Yu-Qi  , Xie Hong-Lan  , Deng Biao  , Xu Hong-Jie  , Wu Li-Hong  , Xue Yan-Ling  ,   (1)Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China; (2)Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China; Graduate School of the Chinese Academy of Sciences, Beijing 100049, China; (3)Shanghai R and D Centre for Standardization of Chinese Medicines, Shanghai 201203, China
Published: December 2020

X-ray phase contrast microscopy (XPCM) achieves the high contrast imaging of low electron density materials with the spatial coherence peculiarity of X-rays. Considering that ginsengs are mainly composed of C, H, O, N and other low-Z elements, XPCM is an ideal tool to nondestructively investigate the characteristic microstructures of ginsengs in principle. Owing to the higher fluxes and luminance of the third generation of synchrotron radiation facility, it can present clearer and finer microstructures of ginsengs with better spatial and temporal resolutions. In this paper, the characteristic microstructures of wild ginseng ware investigated systemically by XPCM at Shanghai Synchrotron Radiation Facility (SSRF). For comparison, the characteristic structures of cultivated ginseng are also studied correspondingly. Moreover, a kind of new microstructure is found in young ginsengs, which is possibly a new characteristic structure of ginsengs. The results demonstrates that XPCM is a promising new method of identifying wild ginseng.
The influence of the time delay through long trunk fiber on the phase-coding quantum key distribution system
Authors: Wang Jin-Dong  , Wei Zheng-Jun  , Zhang Hui  , Zhang Hua-Ni  , Chen Shuai  , Qin Xiao-Juan  , Guo Jian-Ping  , Liao Chang-Jun  , Liu Song-Hao  ,   (1)Guangdong Radio and TV University,Guangzhou 510091,China; (2)Key Laboratory of Photonic Information Technology of Guangdong Higher Education Institutes,School for Information and Optoelectronic Science and Engineering,South China Normal University,Guangzhou 510006, China; (3)Physics Teaching and Research Section,Artillery Academy of Chinese Peoples Liberation Army,Hefei 230031,China
Published: December 2020

Optical pulse will reach the receiver not at exact time instance due to the transmission through the long trunk fiber, and this phenomenon will effect on the bits error rate in the Quantum key distribution (QKD) system to some extend. The time jitter based on the differential phase shift quantum key distribution system and two asymmetric Mach-Zehnder interferometers is measured outdoors in different transmission distance and the physical model of the relationship between the time jitter and the quantum bit error rate is proposed. According to this relationship, the quantum bit error rate can be estimated for some optical pulse shape and some statistical distribution function.
The evolution law of KTP SHG conversion efficiency in special repetition rate
Authors: Xie Xu-Dong  , Zhu Qi-Hua  , Zhang Qiu-Hui  , Feng Guo-Ying  , Han Jing-Hua  , Li Bin-Hou  ,   (1)China Academy of Engineering Physics, Mianyang 621900, China; (2)College of Electronics and Information Engineering, Sichuan University, Chengdu 610064, China
Published: December 2020

Based on the conduction band electron density and the expression of the effective dielectric function, the absorption coefficient at 532nm of KTP crystal is deduced. The evolution law of conduction band electron density, absorption coefficient and second harmonic generation (SHG) conversion efficiency are comparatively studied. The results are as follows. The 532 nm absorption coefficient of KTP crystal is increasing with conduction band electron density, and the SHG conversion efficiency is decreasing with conduction band electron density. When the power density of fundamental frequency laser is a fixed value, conduction band electron density shows accumulation effects a different repetition rates, which caused the 532 nm transmission and the SHG conversion efficiency of KTP crystal to vary exponentially with acting time, and the accumulation effect is increasing obviously with repetition rate, but conduction band electron density and absorption coefficient approach thir steady values.
Measurement of the passive UHF RFID tag’s performance based on software-defined radio
Authors: Hou Zhou-Guo  , He Yi-Gang  , Li Bing  , She Kai  , Zhu Yan-Qing  ,   College of Electrical and Information Engineering, Hunan University, Changsha 410082,China
Published: December 2020

The signal transmission and measurement method of the passive UHF radio-frequency identification(RFID) system are discussed in this paper. Part of tags communication performance which conforms with the ISO/IEC 18000-6 Type C was obtained by using the software-defined radio test platform. The received power by the platform changes with the communication parameters. Sensitivity of different tags was tested. All experiments were conducted under normal conditions.The measurement results show that the small Tari, half duty cycle (PW) and higher modulation index in baseband signal encoding allow the RFID system to receive larger power, also the RFID system to have larger read range.
Simulation of surface segregation of in to Al(001) surface
Authors: Liu Jian-Cai  , Zhang Xin-Ming  , Chen Ming-An  , Tang Jian-Guo  , Liu Sheng-Dan  ,   Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, School of Materials Science and Engineering, Central South University, Changsha 410083, China
Published: December 2020

A new vacancy model by using periodic density functional theory was used to describe the process of In segregation from clean Al surfaces via atomic movement through vacancies. The detailed segregation mechanism of impurity metal In to Al (001) surface planes is examined, carefully evaluating energy barriers for each step in the segregation process. The results show that the system energy is decreased by 0.46 eV and the highest energy barrier is 0.34 eV when the impurity atom In moves from the second layer to the topmost layer in the Al (001) slab. The system energy is almost constant when impurity atoms segregate from the third layer to the second layer. Higher energy (0.65 eV) was needed to overcome the energy barriers. So, In showing a strong segregation to the clean Al (001) surface is thermodynamically favorable.
Study on clock skew of unsymmetrical RLC interconnect tree with temperature distribution
Authors: Wang Zeng  , Dong Gang  , Yang Yin-Tang  , Li Jian-Wei  ,   Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, Microelectronics Institute, Xidian University, Xi'an 710071, China
Published: December 2020

Based on the influence of the nonuniform temperature distribution and the inductance effect of the wires on the interconnect delay time, a zero-clock-skew construction method of RLC interconnect clock tree is presented in this paper. The proposed analytical model has closed form expression and takes temperature distribution, inductance effect and unsymmetrical interconnect structure into consideration. Adopting parameters of 65 nm process technology, the proposed model is compared with the other available similar models. Results show that the new model is more accurate with maximum 1% error.
A first principle study on p-type doped 3C-SiC
Authors: Zhang Yun  , Shao Xiao-Hong  , Wang Zhi-Qiang  ,   (1)College of science,Beijing University of Chemical Technology, Beijing 100029, China; (2)Institute of Optics and Electronics, Chinese Academy of Science, Beijing 100190, China
Published: December 2020

The geometrical and electronic structures, the dopant formation energies, lattice constants, band structure and density of states of p-type SiC are calculated by the first principles of plane wave ultra-soft pseudo-potential method based on density functional theory. The band structures of different concentrations of B, Al and Ga are calculated. The results of the electronic structure show that the band gap narrows with the increase of doping concentration of B and the band gap widens with the increase of doping concentration of Al and Ga. At the same concentration the band gap of Ga doped SiC is wider than that of Al doped SiC, the band gap of Al doped SiC is wider than B doped SiC.
Molecular dynamics simulations of pulsed laser crystallization of amorphous silicon ultrathin films
Authors: Chen Gu-Ran  , Song Chao  , Xu Jun  , Wang Dan-Qing  , Xu Ling  , Ma Zhong-Yuan  , Li Wei  , Huang Xin-Fan  , Chen Kun-Ji  ,   National Laboratory of Solid State Microstructures, Jiangsu Provincial Key Laboratory of Photonic and Electronic MaterialsSciences and Technology, Department of Physics, Nanjing University, Nanjing 210093, China
Published: December 2020

Laser crystallization of amorphous Si thin films is one of reliable method of preparing nanocrystalline silicon with high density and controllable size. In the present work, molecular dynamics simulation based on Tersoff potential was used to study the laser crystallization process of ultrathin amorphous silicon film (2.7 nm) on amorphous silicon nitride substrate. The influence of laser fluences on the crystallization and formation of nanocrystalline Si was investigated. It was found that there exists a laser fluence window in which nucleation and growth of nanocrystalline Si can be realized, which is in agreement with our previous experimental observations. The nucleation and growth processes in microscopic scale were simulated and the size of formed nanocrystalline Si was limited in both vertical and lateral directions by the film thickness and the formation of grain boundaries.
Growth and character stics of AlGaN/GaN HEMT structures with AlN/GaN superlattices as barrier layers
Authors: Ding Guo-Jian  , Guo Li-Wei  , Xing Zhi-Gang  , Chen Yao  , Xu Pei-Qiang  , Jia Hai-Qiang  , Zhou Jun-Ming  , Chen Hong  ,   Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

We report the growth and characterization of AlGaN/GaN heterostructures with AlN/GaN superlattices as the barrier layer.It is found that the surface morphology of the heterostructure is greatly improved compared with those using the conventional alloy AlGaN barrier layer.Meanwhile, electric properties of samples with high Al composition (≥40%) are superior to the conventional alloy sanples.Low sheet resistance (251 Ω/□) is obtained for our samples with 40% Al content.
Millimeter wavelength coherent emission from high temperature superconducting bicrystal Josephson junction array
Authors: Yue Hong-Wei  , Wang Zheng  , Fan Bin  , Song Feng-Bin  , You Feng  , Zhao Xin-Jie  , He Ming  , Fang Lan  , Yan Shao-Lin  ,   Department of Electronics Information Science and Technology,College of Information Technical Science,Nankai University,Tianjin 300071,China
Published: December 2020

The experimental results of mm-wave coherent emission from a high temperature superconducting bicrystal Josephson junction array embedded in a Fabry-Perot resonator are reported in this paper.The mm-wave coherent emission from the series junction array results from the interaction of the junctions with the substrate serving as the dielectric resonator as well as the Fabry-Perot resonator.The central frequency of emission of a Josephson junction array containing 166 bicrystal junctions was 75.84 GHz,and the detected emission power was about 10 pW at 77 K.
Research on order phase and second-entering-type spin glass behavior of La0.3Ca0.7Mn1－xVxO3 system
Authors: Yan Guo-Qing  , Mao Qiang  , Wang Gui-Ying  , Guo Huan-Yin  , Liu Ning  ,   (1)Anhui Key Laboratory of Spin Electron and Nanomaterials (Cultivating Base),Suzhou College,Suzhou 234000,China; (2)College of sciences,Anhui Science and Technology University,Fengyang 233100,China; Anhui Key Laboratory of Spin Electron and Nanomaterials (Cultivating Base),Suzhou College,Suzhou 234000,China
Published: December 2020

The influence of V doping at Mn site on charge order and spin order of La0.3Ca0.7MnO3 system has been studied by the measurement of magnetization-temperature (M-T) curves,resistivity-temperature (ρ-T) curves and electron spin resonance (ESR) spectra of samples La0.3Ca0.7Mn1－xVxO3 (x=0.05,0.10,0.134,0.20).The results show that, when 0.05≤3≤0.134,charge ordering (CO) phase exists in the system,and the spin order of the system exhibits the serial changes of paramagnetism (PM)—charge ordering (CO)—antiferromagnetism (AFM) with the decrease of temperature.When x=0.20,the charge ordering melts,and the system exhibits second-entering-type spin glass behavior.
Mixed former effect on thermal stability and spectroscopic properties of Er3+-doped tellurite glasses
Authors: Chen Dong-Dan  , Zhang Qin-Yuan  , Jiang Zhong-Hong  ,   Key laboratory of specially functional materials,Ministry of Education,Institute of optical communication materials,South China University of technology,Guangzhou 510640,China
Published: December 2020

The influence of mixed former effect on the thermal stability,1.53 μm emission and the infrared to visible upconversion emission of the Er3+-doped tellurite glasses are investigated.The inhomogeneous broadening of emission spectrum of Er3+ ion with several network formers (WO3,Nb2O5 and GeO2)is discussed by Raman spectra.The results indicate that for Er3+-doped tellurite glass,besides improving the thermal stability of glasses,introducing the network former with appropriate phonon energy is helpful for the improvement of 1.53 μm emission via decreasing the lifetime of Er3+ ∶4 I11/2 level,and lowering the upconversion luminescence in visible wavelength.The present glasses exhibit a large emission cross section ((9.64—10.96)×10-21 cm2)and broad full width at half maximum (FWHM)(50—67 nm),which make them promising host materials for broadband Er3+-doped fiber.