bluuebunny/crossref_metadata_2025_split huggingface dataset:
Is there evidence for a 4.2 ka BP event in the northern North Atlantic region?
Authors: Bradley Raymond S. , Bakke Jostein 
Published: September 2019

Abstract. We review paleoceanographic and paleoclimatic records from the northern
North Atlantic to assess the nature of climatic conditions at 4.2 ka BP,
which has been identified as a time of exceptional climatic anomalies in
many parts of the world. The northern North Atlantic region experienced
relatively warm conditions from 6 to 8 ka BP, followed by a general decline
in temperatures after ∼5 ka BP, which led to the onset of
neoglaciation. Over the last 5000 years, a series of multi-decadal- to
century-scale fluctuations occurred, superimposed on an overall decline in
temperature. Although a few records do show a glacial advance around 4.2 ka BP, because they are not widespread we interpret them as local events –
simply one glacial advance of many that occurred in response to the overall
climatic deterioration that characterized the late Holocene.
Análise espacial dos fatores determinantes das pastagens no baixo Amazonas/PA
Authors: Corrêa Jéssica Ariana de Jesus , Santos José Laurindo Campos dos , Andrade Silvia Cristina de Pádua , Costa Izaura Cristina Nunes Pereira , Silva Júlio Tota da 
Published: September 2019

O presente trabalho teve por objetivo analisar a dinâmica espacial de áreas de pastagens e verificar os principais fatores que contribuem para sua distribuição na região do Baixo Amazonas nos anos de 2000 e 2014. Foi utilizada análise de regressão espacial sendo as porcentagens de pastagem como variáveis dependentes e, como variáveis independentes, fatores ambientais, de acessibilidade, políticas públicas, estrutura fundiária, economia e demográficos relacionados com a presença de pastagens. Observou-se que as áreas de pastagem em 2000 eram de 15.767,12 Km² enquanto que em 2014 aumentou para 18.657,58 Km². Além disso, os resultados mostraram que as áreas de pastagens naturais ainda são em maior proporção que áreas de pastagens cultivadas com um incremento de 0,23% em 2014 quando comparado com o ano 2000, porém as pastagens plantadads apresentaram crescimento em 11,64% de área. A concentração das pastagens naturais estão próximas a planície de inundação, enquanto que a expansão das pastagens plantadas ocorrem em áreas com presença de estradas e rodovias. Os resultados da análise de regressão mostraram que a porcentagem de área com a agricultura e precipitação anual foram as variáveis explicativas que se relacionaram nos dois anos para os dois tipos de pastagens. Para as pastagens plantadas a variável explicativa mais significativa foi os estabelecimentos agropecuários com pecuária com coeficiente de -0,37 e 0,24 em 2000 e 2014, respectivamente. Verificou-se que o estabelecimento de áreas protegidas são cruciais pois atuam como barreiras para a expansão das áreas de pastagens plantadas e que, estradas e rodovias favorecem a implantação de pastagens em seu entorno. A modelagem estatística e espacialmente explícita mostrou ser uma ferramenta útil de análise para compreender os processos e padrões de mudanças de uso e cobertura da terra, em específico a distribuição das pastagens no Baixo Amazonas.
Sinais dos Tempos, uma questão hermenêutica
Authors: Suzuki Francisca Cirlena 
Published: September 2019

Com alegria e esperança, lança-se luz sobre os problemas do mundo, através da Gaudium et Spes, uma Constituição Pastoral. De modo simples, a Igreja Católica olha com naturalidade o que a humanidade enfrenta nos âmbitos da vida, sejam eles econômicos, políticos e/ou sociais. O olhar da Igreja Católica Apostólica Romana se voltou para as misérias humanas, em sua concretude, durante anos de discussões em conferências, aulas e muito estudo dentro do Concílio Vaticano II sob o título de os Sinais dos Tempos. Embora o termo tenha percorrido um longo caminho e recebido muitas reelaborações, contando muitas idas e vindas em busca de um entendimento para esse termo aplicado ao mundo. Ainda assim, estabelecem-se indagações a respeito de sua hermenêutica: o que teria demandado tantas reflexões dos Padres Conciliares sobre a interpretação do termo Sinais dos Tempos? Teria sido a dificuldade encontrada em articular os significados dos Sinais dos Tempos do Papa João XXIII com os Sinais dos Tempos do Evangelho (Mt 16,3)?
Extraversion, Secure Attachment dan Perilaku Cyberbullying
Authors: Safaria Triantoro , Rizal Irfani 
Published: September 2019

Riset-riset sebelumnya menunjukkan bahwa perbedaan individual seperti kepribadian dan gaya attachment dapat memprediksi perilaku bullying dan cyberbullying. Meski demikian, masih ditemukan adanya inkonsistensi dalam temuan-temuan sebelumnya. Penelitian ini menguji apakah dimensi kepribadian extraversion dan secure attachment berperan dalam munculnya perilaku cyberbullying. Partisipan dalam penelitian ini berjumlah 199 siswa SMP. Analisis regresi digunakan untuk menguji hipotesis yang diajukan. Hasil penelitian ini menunjukkan bahwa rendahnya skor extraversion memprediksi tingginya skor cyberbullying. Sementara itu rendahnya skor secure attachment memprediksi tingginya skor cyberbullying. Rekomendasi dan saran dijelaskan lebih lanjut dalam artikel ini.
Axial and Radial Variation of Fibre Characteristics of Bambusa vulgaris
Authors: Aderounmu A. F. , Adelusi E. A. 
Published: September 2019

This study was carried out to investigate the axial and radial variations of fibre characteristics of Bambusa vulgaris. There were eighteen treatments for both axial and radial variations. The treatments were replicated three (3) times, in Complete Randomized Design (CRD). The experiment was carried out at the Wood Anatomy Laboratory of the Department of Forest Product Development and Utilization, Forestry Research Institute of Nigeria, Ibadan. Three samples (3) stands of B. vulgaris were randomly selected. Samples collected were cut into 10cm discs at 25%, 50% and 75% of the total height (axial positioning). The samples discs were partitioned into two zones which are core and peripheral (bark) layers. From each of the disc, 3 slivers were obtained both from radial and axial positions. Slivers obtained were macerated with an equal volume (1:1) of 10% glacial Acetic acid and 30% Hydrogen Peroxide (H2O2) at 100 ±2°C. The resulting image on light microscope screen was measured for fibre length, fibre diameter and lumen width.
At 50% sampling height and at outer layer, the highest fibre length of 3.25 mm, followed by 3.06 mm of bamboo sample stand 3 while the least 2.28 mm was recorded in sample stands 2 of 75% axial positioning and at peripheral layer. The lumen width ranged between 3.52 × 10-3 μm to 4.46 × 10-3 μm in the radial direction from the core to the peripheral (bark) of the bamboo. The result obtained for mean values of fiber diameter along the bamboo height ranged from 3.53 × 10-3 µm to 4.46 × 10-3 µm across the three (3) bamboo stands, sampling height and radial direction sampling respectively.
Among the fibre positioning, the fibre collected from 50% of the sampling height have higher fibre diameter, lumen width and fibre diameter at the peripheral region compare to the others.
Visualization of Dopant Oxygen Atoms in a Bi2Sr2CaCu2O8+δ Superconductor
Authors: Song Dongsheng , Zhang Xuefeng , Lian Chaosheng , Liu Hai , Alexandrou Ioannis , Lazić Ivan , Bosch Eric G. T. , Zhang Ding , Wang LiLi , Yu Rong , Cheng Zhiying , Song Canli , Ma Xucun , Duan Wenhui , Xue Qikun , Zhu Jing 
Published: September 2019

AbstractA proper amount of excess oxygen plays a significant role in hole‐doped cuprate high‐Tc superconductivity. Here, the dopant oxygen in Bi2Sr2CaCu2O8+δ is directly imaged via integrated differential phase contrast combined with state‐of‐the‐art scanning transmission electron microscopy. The location of dopant oxygen is observed to be consistent with the position inferred from local strain analysis of the incommensurate structure. The influence of dopant oxygen on the local atomic lattice and electronic structure is further explored using first‐principle calculations. The dopant oxygen atoms not only aggravate the distortions of the local atomic arrangement but also alter the electronic states by transferring charge from the BiO planes to the CuO2 planes. The underlying mechanism of charge transfer is resolved. The results may also be applicable to other oxygen‐doped cuprates with high‐Tc superconductivity.
Distinctive Performance of Terahertz Photodetection Driven by Charge‐Density‐Wave Order in CVD‐Grown Tantalum Diselenide
Authors: Wang Lin , Wang Jin , Liu Changlong , Xu Huang , Li Ang , Wei Dacheng , Liu Yunqi , Chen Gang , Chen Xiaoshuang , Lu Wei 
Published: September 2019

AbstractThe quantum behavior of carriers in solid is the foundation of modern electronic and optoelectronic technology, but it is still facing huge challenges within inherited single‐particle quantum processes working at the millimeter wave/terahertz (THz) band. Here, a straightforward strategy for the direct detection of millimeter wave/THz photons in a sub‐wavelength metal‐TaSe2‐metal structure under strong interaction with a localized field of surface plasmon is proposed. By breaking the inversion symmetry under the perturbations of electric field and atomic reconstruction from van der Waals integration, the nonequilibrium electronic states under a radiant field can be manipulated in a collective fashion, leading to a large photocurrent responsivity over 40 A W−1 and noise equivalent power less than 1 pW Hz−1/2 even at room temperature. A more than 40‐fold enhancement in responsivity is achieved when transitioning from the normal phase to the CDW phase. The findings shed fresh light on the understanding of the delicate balance in the charge‐ordered phase, and facilitate the exploitation of a correlated electron system for optoelectronic applications in fields of security, remote sensing, and imaging.
π‐Conjugation Enables Ultra‐High Rate Capabilities and Cycling Stabilities in Phenothiazine Copolymers as Cathode‐Active Battery Materials
Authors: Acker Pascal , Rzesny Luisa , Marchiori Cleber F. N. , Araujo C. Moyses , Esser Birgit 
Published: September 2019

AbstractIn recent years, organic battery cathode materials have emerged as an attractive alternative to metal oxide–based cathodes. Organic redox polymers that can be reversibly oxidized are particularly promising. A drawback, however, often is their limited cycling stability and rate performance in a high voltage range of more than 3.4 V versus Li/Li+. Herein, a conjugated copolymer design with phenothiazine as a redox‐active group and a bithiophene co‐monomer is presented, enabling ultra‐high rate capability and cycling stability. After 30 000 cycles at a 100C rate, >97% of the initial capacity is retained. The composite electrodes feature defined discharge potentials at 3.6 V versus Li/Li+ due to the presence of separated phenothiazine redox centers. The semiconducting nature of the polymer allows for fast charge transport in the composite electrode at a high mass loading of 60 wt%. A comparison with three structurally related polymers demonstrates that changing the size, amount, or nature of the side groups leads to a reduced cell performance. This conjugated copolymer design can be used in the development of advanced redox polymers for batteries.
Oxide Catalysts with Ultrastrong Resistance to SO2 Deactivation for Removing Nitric Oxide at Low Temperature
Authors: Ma Zhaoxia , Sheng Liping , Wang Xinwei , Yuan Wentao , Chen Shiyuan , Xue Wei , Han Gaorong , Zhang Ze , Yang Hangsheng , Lu Yunhao , Wang Yong 
Published: September 2019

AbstractNitrogen oxides are one of the major sources of air pollution. To remove these pollutants originating from combustion of fossil fuels remains challenging in steel, cement, and glass industries as the catalysts are severely deactivated by SO2 during the low‐temperature selective catalytic reduction (SCR) process. Here, a MnOX/CeO2 nanorod catalyst with outstanding resistance to SO2 deactivation is reported, which is designed based on critical information obtained from in situ transmission electron microscopy (TEM) experiments under reaction conditions and theoretical calculations. The catalysts show almost no activity loss (apparent NOX reaction rate kept unchanged at 1800 µmol g−1 h−1) for 1000 h test at 523 K in the presence of 200 ppm SO2. This unprecedented performance is achieved by establishing a dynamic equilibrium between sulfates formation and decomposition over the CeO2 surface during the reactions and preventing the MnOX cluster from the steric hindrance induced by SO2, which minimized the deactivation of the active sites of MnOX/CeO2. This work presents the ultralong lifetime of catalysts in the presence of SO2, along with decent activity, marking a milestone in practical applications in low‐temperature selective catalytic reduction (SCR) of NOX.
In Situ Liquid Cell TEM Studies on Etching and Growth Mechanisms of Gold Nanoparticles at a Solid–Liquid–Gas Interface
Authors: Hutzler Andreas , Fritsch Birk , Jank Michael P. M. , Branscheid Robert , Martens R. Christian , Spiecker Erdmann , März Martin 
Published: September 2019

AbstractEtching and growth of gold nanoparticles at a solid–liquid–gas interface are investigated via in situ liquid cell transmission electron microscopy. For this purpose, the gold precursor tetrachloroauric acid is enclosed in the wells of a free‐standing, locally thinned silicon nitride film covered by few‐layer graphene. Etching of gold is attributed to hydroxide radicals generated by radiolysis and gaseous species which are located within a gas bubble. The etching mechanism comprises two distinct cases. In one case, the gas bubble is in direct contact with the gold particle, separated only by a thin liquid membrane. In the other case, the gold particle is thoroughly immersed in liquid in the vicinity of the particle. In the latter, etching molecules diffuse from the bubble through the liquid toward the surface of the nanoparticle and subsequently etch the gold platelet. During the particle etching process, concurrent nucleation and ripening of gold nanoparticles are observed. This growth is induced by local supersaturation of the solution with gold ions. Experimental results show that the growth process is limited by diffusion, even though the diffusivity of reactants is very low due to narrow‐channel effects compared against the diffusivity of solvated ions in bulk liquids.
Robust Production of Well‐Controlled Microdroplets in a 3D‐Printed Chimney‐Shaped Milli‐Fluidic Device
Authors: Hwang Yoon‐Ho , Um Taewoong , Hong Jiwoo , Ahn Gwang‐Noh , Qiao Juan , Kang In Seok , Qi Li , Lee Hyomin , Kim Dong‐Pyo 
Published: September 2019

Abstract3D‐printing technology has recently been exploited in droplet microfluidics due to its simplicity and low cost. Unresolved, however, is the design and fabrication of 3D‐printed droplet generators that allow high throughput production of monodisperse droplets with sizes ranging from tens to hundreds of microns in a robust manner. Herein, a newly designed 3D‐printed milli‐fluidic device with a chimney‐shaped void geometry that produces monodisperse droplets controllably with the size covering a broad range is reported. The droplet generator with four parallelized chimneys is devised to simultaneously generate droplets of various size as well as spherical glycine crystals of various size in a single system, demonstrating its potential as a point‐of‐care medicine manufacturing platform.
Large‐Area and Low‐Cost Nanoslit‐Based Flexible Metasurfaces for Multispectral Electromagnetic Wave Manipulation
Authors: Zhang Ming , Ma Xiaoliang , Pu Mingbo , Liu Kaipeng , Guo Yinghui , Huang Yijia , Xie Xin , Li Xiong , Yu Honglin , Luo Xiangang 
Published: September 2019

AbstractManipulating multispectral electromagnetic (EM) waves has drawn great attention due to its potential applications in EM compatibility, radiative cooling, and multispectral imaging. Metasurfaces are intensively investigated to control EM waves and achieve versatile functions. However, the design of multispectral manipulation and the fabrication of multiscale metasurfaces remain a great challenge. Here, a multiscale flexible metasurface with nanometer‐sized characteristic dimensions and a square centimeter sized area is designed and fabricated for the simultaneous manipulation of infrared and terahertz waves. A simple yet powerful analytic method derived from catenary field theory is proposed to guide the design. A metasurface consisting of 2D nanoslit array is fabricated onto a flexible polyimide substrate by combining shadow mask fabrication with surface plasmon lithography to achieve nanoscale, large‐area, and repeatable fabrication. The experimental results show that the proposed metasurface possesses high reflectance exceeding 95% within the 8–12 µm wavelength range, indicating low thermal emissivity. Additionally, the metasurface exhibits low reflection in the THz regime and is capable of implementing integrated functions in conjunction with THz devices. Furthermore, the significant advantage of flexibility affords the metasurface excellent compatibility with irregular surfaces. This work may provide important guidance for the design and fabrication of large‐scale multispectral metasurfaces.
Degradation Mechanisms in Organic Lead Halide Perovskite Light‐Emitting Diodes
Authors: Prakasam Vittal , Tordera Daniel , Bolink Henk J. , Gelinck Gerwin 
Published: September 2019

AbstractOrganic–inorganic metal halide perovskites have attracted significant attention for low‐cost, high‐efficiency, color‐pure light‐emitting applications. However, as seen in many reports so‐far, perovskite light‐emitting diodes (PeLED) suffer from poor operational lifetime, limiting their practical use. The underlying degradation mechanism is a topic of crucial importance. Here, the degradation mechanisms of methylammonium lead bromide based PeLED are investigated. When the PeLED is electrically biased, there is an initial raise in the luminance followed by a rapid reduction in luminance and current density. Microscopic studies reveal the formation of micrometer‐sized spots that are photoluminescent but not electroluminescent. It is demonstrated that this degradation is due to the formation of gaseous compounds that leads to local delamination of the cathode, thereby reducing the electroluminescence. When the degraded cathode is substituted with a fresh cathode, the initial luminance is largely recovered. By further analyzing the buried interface of the cathode, the formation of lead bromide and gaseous methylamine due to the degradation of the perovskite layer are revealed. These insights will help to further improve the lifetime of PeLEDs. As an example, it is shown that substituting methylammonium cations by cesium leads to longer lifetimes.
Flexible Luminescent Organic Bulk Crystal: 2D Elasticity toward 3D Optical Waveguide
Authors: Huang Rui , Tang Baolei , Ye Kaiqi , Wang Chenguang , Zhang Hongyu 
Published: September 2019

AbstractThe study of elastic organic single crystals becomes a hot research field in the crystal engineering, and elastic bending of needle‐like crystals has been carefully investigated recently. Herein, based on a structurally simple molecule dimethyl 2,5‐diaminoterephthalate (DMDAT), the organic crystals which display not only elastic bending ability but also elastic twisting ability under applied stress are reported. These ribbon‐like DMDAT crystals are fully flexible and can be freely bended and twisted, thus forming any 3D conformation. Moreover, the unique X‐shaped tetrasubstituted benzene structure enables DMDAT crystals to display efficient yellow emission based on a very small π‐system. Taking these advantages, 3D optical waveguide is successfully realized in the DMDAT crystal with a highly twisted 3D belt‐shaped structure, demonstrating the ultimate 3D application of flexible organic bulk crystals.
Accelerated Search for BaTiO3‐Based Ceramics with Large Energy Storage at Low Fields Using Machine Learning and Experimental Design
Authors: Yuan Ruihao , Tian Yuan , Xue Dezhen , Xue Deqing , Zhou Yumei , Ding Xiangdong , Sun Jun , Lookman Turab 
Published: September 2019

AbstractThe problem that is considered is that of maximizing the energy storage density of Pb‐free BaTiO3‐based dielectrics at low electric fields. It is demonstrated that how varying the size of the combinatorial search space influences the efficiency of material discovery by comparing the performance of two machine learning based approaches where different levels of physical insights are involved. It is started with physics intuition to provide guiding principles to find better performers lying in the crossover region in the composition–temperature phase diagram between the ferroelectric phase and relaxor ferroelectric phase. Such an approach is limiting for multidopant solid solutions and motivates the use of two data‐driven machine learning and design strategies with a feedback loop to experiments. Strategy I considers learning and property prediction on all the compounds, and strategy II learns to preselect compounds in the crossover region on which prediction is carried out. By performing only two active learning loops via strategy II, the compound (Ba0.86Ca0.14)(Ti0.79Zr0.11Hf0.10)O3 is synthesized with the largest energy storage density ≈73 mJ cm−3 at a field of 20 kV cm−1, and an insight into the relative performance of the strategies using varying levels of knowledge is provided.
Enhanced Near‐Infrared Photoresponse of Inverted Perovskite Solar Cells Through Rational Design of Bulk‐Heterojunction Electron‐Transporting Layers
Authors: Chen Chih‐I , Wu Shengfan , Lu Yen‐An , Lee Chia‐Chen , Ho Kuo‐Chuan , Zhu Zonglong , Chen Wen‐Chang , Chueh Chu‐Chen 
Published: September 2019

AbstractHow to extend the photoresponse of perovskite solar cells (PVSCs) to the region of near‐infrared (NIR)/infrared light has become an appealing research subject in this field since it can better harness the solar irradiation. Herein, the typical fullerene electron‐transporting layer (ETL) of an inverted PVSC is systematically engineered to enhance device's NIR photoresponse. A low bandgap nonfullerene acceptor (NFA) is incorporated into the fullerene ETL aiming to intercept the NIR light passing through the device. However, despite forming type II charge transfer with fullerene, the blended NFA cannot enhance the device's NIR photoresponse, as limited by the poor dissociation of photoexciton induced by NIR light. Fortunately, it can be addressed by adding a p‐type polymer. The ternary bulk‐heterojunction (BHJ) ETL is demonstrated to effectively enhance the device's NIR photoresponse due to the better cascade‐energy‐level alignment and increased hole mobility. By further optimizing the morphology of such a BHJ ETL, the derived PVSC is finally demonstrated to possess a 40% external quantum efficiency at 800 nm with photoresponse extended to the NIR region (to 950 nm), contributing ≈9% of the overall photocurrent. This study unveils an effective and simple approach for enhancing the NIR photoresponse of inverted PVSCs.