Friction force microscopy : a simple technique for identifying graphene on rough substrates and mapping the orientation of graphene grains on copper

At a single atom thick, it is challenging to distinguish graphene from its substrate using conventional techniques. In this paper we show that friction force microscopy (FFM) is a simple and quick technique for identifying graphene on a range of samples, from growth substrates to rough insulators. We show that FFM is particularly effective for characterizing graphene grown on copper where it can correlate the graphene growth to the three-dimensional surface topography. Atomic lattice stick–slip friction is readily resolved and enables the crystallographic orientation of the graphene to be mapped nondestructively, reproducibly and at high resolution. We expect FFM to be similarly effective for studying graphene growth on other metal/locally crystalline substrates, including SiC, and for studying growth of other two-dimensional materials such as molybdenum disulfide and hexagonal boron nitride

DancingLines: An Analytical Scheme to Depict Cross-Platform Event Popularity

Nowadays, events usually burst and are propagated online through multiple modern media like social networks and search engines. There exists various research discussing the event dissemination trends on individual medium, while few studies focus on event popularity analysis from a cross-platform perspective. Challenges come from the vast diversity of events and media, limited access to aligned datasets across different media and a great deal of noise in the datasets. In this paper, we design DancingLines, an innovative scheme that captures and quantitatively analyzes event popularity between pairwise text media. It contains two models: TF-SW, a semantic-aware popularity quantification model, based on an integrated weight coefficient leveraging Word2Vec and TextRank; and wDTW-CD, a pairwise event popularity time series alignment model matching different event phases adapted from Dynamic Time Warping. We also propose three metrics to interpret event popularity trends between pairwise social platforms. Experimental results on eighteen real-world event datasets from an influential social network and a popular search engine validate the effectiveness and applicability of our scheme. DancingLines is demonstrated to possess broad application potentials for discovering the knowledge of various aspects related to events and different media

Charge states and magnetic ordering in LaMnO3/SrTiO3 superlattices

We investigated the magnetic and optical properties of [(LaMnO3)n/(SrTiO3)8]20 (n = 1, 2, and 8) superlattices grown by pulsed laser deposition. We found a weak ferromagnetic and semiconducting state developed in all superlattices. An analysis of the optical conductivity showed that the LaMnO3 layers in the superlattices were slightly doped. The amount of doping was almost identical regardless of the LaMnO3 layer thickness up to eight unit cells, suggesting that the effect is not limited to the interface. On the other hand, the magnetic ordering became less stable as the LaMnO3 layer thickness decreased, probably due to a dimensional effect.Comment: 17 pages including 4 figures, accepted for publication in Phys. Rev.

Neutron-rich rare isotope production from projectile fission of heavy beams in the energy range of 20 MeV/nucleon

We investigate the possibilities of producing neutron-rich nuclides in projectile fission of heavy beams in the energy range of 20 MeV/nucleon expected from low-energy facilities. We report our efforts to theoretically describe the reaction mechanism of projectile fission following a multinucleon transfer collision at this energy range. Our calculations are mainly based on a two-step approach: the dynamical stage of the collision is described with either the phenomenological Deep-Inelastic Transfer model (DIT), or with the microscopic Constrained Molecular Dynamics model (CoMD). The deexcitation/fission of the hot heavy projectile fragments is performed with the Statistical Mul- tifragmentation Model (SMM). We compared our model calculations with our previous experimental projectile-fission data of 238U (20 MeV/nucleon)+208Pb and 197Au (20 MeV/nucleon)+197Au and found an overall reasonable agreement. Our study suggests that projectile fission following periph- eral heavy-ion collisions at this energy range offers an effective route to access very neutron-rich rare isotopes toward and beyond the astrophysical r-process path

Ultramafic xenoliths from the Bearpaw Mountains, Montana, USA: evidence for multiple metasomatic events in the lithospheric mantle beneath the Wyoming craton

Ultramafic xenoliths in Eocene minettes of the Bearpaw Mountains volcanic field (Montana, USA), derived from the lower lithosphere of the Wyoming craton, can be divided based on textural criteria into tectonite and cumulate groups. The tectonites consist of strongly depleted spinel lherzolites, harzburgites and dunites. Although their mineralogical compositions are generally similar to those of spinel peridotites in off-craton settings, some contain pyroxenes and spinels that have unusually low Al2O3 contents more akin to those found in cratonic spinel peridotites. Furthermore, the tectonite peridotites have whole-rock major element compositions that tend to be significantly more depleted than non-cratonic mantle spinel peridotites (high MgO, low CaO, Al2O3 and TiO2) and resemble those of cratonic mantle. These compositions could have been generated by up to 30% partial melting of an undepleted mantle source. Petrographic evidence suggests that the mantle beneath the Wyoming craton was re-enriched in three ways: (1) by silicate melts that formed mica websterite and clinopyroxenite veins; (2) by growth of phlogopite from K-rich hydrous fluids; (3) by interaction with aqueous fluids to form orthopyroxene porphyroblasts and orthopyroxenite veins. In contrast to their depleted major element compositions, the tectonite peridotites are mostly light rare earth element (LREE)-enriched and show enrichment in fluid-mobile elements such as Cs, Rb, U and Pb on mantle-normalized diagrams. Lack of enrichment in high field strength elements (HFSE; e.g. Nb, Ta, Zr and Hf) suggests that the tectonite peridotites have been metasomatized by a subduction-related fluid. Clinopyroxenes from the tectonite peridotites have distinct U-shaped REE patterns with strong LREE enrichment. They have 143Nd/144Nd values that range from 0·5121 (close to the host minette values) to 0·5107, similar to those of xenoliths from the nearby Highwood Mountains. Foliated mica websterites also have low 143Nd/144Nd values (0·5113) and extremely high 87Sr/86Sr ratios in their constituent phlogopite, indicating an ancient (probably mid-Proterozoic) enrichment. This enriched mantle lithosphere later contributed to the formation of the high-K Eocene host magmas. The cumulate group ranges from clinopyroxene-rich mica peridotites (including abundant mica wehrlites) to mica clinopyroxenites. Most contain >30% phlogopite. Their mineral compositions are similar to those of phenocrysts in the host minettes. Their whole-rock compositions are generally poorer in MgO but richer in incompatible trace elements than those of the tectonite peridotites. Whole-rock trace element patterns are enriched in large ion lithophile elements (LILE; Rb, Cs, U and Pb) and depleted in HFSE (Nb, Ta Zr and Hf) as in the host minettes, and their Sr–Nd isotopic compositions are also identical to those of the minettes. Their clinopyroxenes are LREE-enriched and formed in equilibrium with a LREE-enriched melt closely resembling the minettes. The cumulates therefore represent a much younger magmatic event, related to crystallization at mantle depths of minette magmas in Eocene times, that caused further metasomatic enrichment of the lithosphere

Жаростойкий сорт перца демонстрирует высокие показатели хлорофилла, фотосинтеза, устьичной проводимости и транспирации в режиме теплового стресса на стадии развития плодов

Relevance. Abiotic stress, as heat, significantly affect plant and floral organs growth and development, fruit set, productivity, the quality, and survival of crops. Heat injury occurs when plants are exposed to these temperatures for a long period of time. Depending on the intensity and duration of exposure to the high temperatures, photosynthesis, respiration, membrane integrity, water relations and the hormone balance of the plants may affected.Material and methods. In this study used the commercial pepper cultivar “NW Bigarim” (HT37) released in South Korea and accessions “Kobra” (HT1) and “Samchukjaere” (HT7) selected as heat tolerant and susceptible, respectively. Total chlorophyll index and photosynthetic activities measured using a SPAD meter (Konica, Japan) and portable photosynthesis measurement system (LI-6400, LI-COR Bioscience, Lincoln, NE, USA), respectively.Results. To evaluate the positive effects of high temperature regime (40/28°C day/night, 14/10-h light/dark cycle) on the response of photosynthetic parameters in pepper plants with different heat susceptibility, we measured the total chlorophyll content (CHL) and photosynthetic activities such as photosynthesis (Pn), stomatal conductance to H2O (Gs) and transpiration rate (Tr) in a heat-tolerant (HT1) and -susceptible cultivars (HT7) in comparison with released cultivar (HT37) at fruit development stage. Heat-tolerant cultivars showed higher and more stable index of the CHL, Pn, Gs and Tr than those in heat-sensitive cultivars for 14 days of heat treatment (HT) period. However, the initial index of Pn, Gs and Tr showed significant alteration among pepper plants regardless of thermotolerance rate before HT on day 0 and day 7 after recovery at normal treatment condition (NT) except for CHL, meaning that plants response to high temperature regime is different from that in normal condition. These results suggest that constant high rates of Pn, Gs and Tr as well as of CHL in heat stress condition periods confer to avoid from heat injury during reproductive growth stages.Актуальность. Абиотический стресс, такой как высокая температура, существенно влияет на рост и развитие репродуктивных органов растений, завязываемость плодов, продуктивность, качество и выживание. При длительном воздействия высоких температур у растений наблюдаются повреждения, и в зависимости от продолжительности и интенсивности высоких температур нарушается фотосинтез, транспирация, целостность мембраны, водный и гормональный баланс.Материал и методика. В данной работе использовали районированный в Южной Корее сорт перца «NW Bigarim» (HT37), а также сортообразцы «Kobra» (HT1) и «Samchukjaere» (HT7) выделенные как устойчивый и восприимчивый к высоким температурам, соответственно. Фотосинтез и общее содержание хлорофилла в листьях определяли при помощи портативного системы (LI-6400, LI-COR Bioscience, Lincoln, NE, USA) и спадметера (Konica Japan), соответственно.Результаты. Изучено и выявлено положительное влияние высокотемпературного режима (40/28°C день/ночь, 14/10-часовой цикл свет/темнота) на реакцию фотосинтетических параметров у растений перца с различной тепловой восприимчивостью, измерено общее содержание хлорофилла (CHL) и фотосинтетической активности, таких параметров, как фотосинтез (Pn), устьичная проводимость в H2O (Gs) и скорость транспирации (Tr) у листьев термостойкого (HT1) и чувствительного сортов (HT7) в сравнении с районированным сортом (HT37) на стадии развития плода. Термостойкий сорт показал более высокие и более стабильные показатели CHL, Pn, Gs и Tr, чем термочувствительный сорт HT7 в течение 14 дней термической обработки (HT). Однако исходные показатели Pn, Gs и Tr показали значительную вариабельность среди растений перца независимо от степени термотолерантности перед обработкой высокой температурой на 0 день и на день 7 после восстановления при нормальных условиях выращивание (NT), за исключением CHL, что означает, что растения реагируют на высокотемпературный режим, отличающийся от условий роста в NT. Эти результаты предполагают, что постоянное высокое снижение Pn, Gs и Tr, а также CHL в периоды теплового стресса позволяет избежать теплового повреждения на стадиях репродуктивного роста растений

Sex determination from partial segments and maximum femur lengths in Koreans using computed tomography

Background: The aim of this study was to establish standards for determining sex from fragmentary and complete femurs in a Korean population.Materials and methods: The statistical analysis of 12 variables (6 about breadth and 6 about length) based on 100 Korean femurs (from 50 males and 50 females) showed that all variables have significant sex differences.Results: The most accurate discriminant variable was the condylar breadth parallel with epicondylar breadth (87.6% accuracy). In contrast, the transverse shaft diameter was not a discriminant variable for sex determination (67.0% accuracy). Breadth-related variables were generally more accurate than length-related variables. Three variables (vertical diameter of the neck [VDN], medial epicondylarlength [MCL], and condylar breadth [CB]) were selected from stepwise analysis fordiscriminating sex (93.5% accuracy). The discriminating equation was as follows: 0.171 × VDN + 0.172 × MCL + 0.128 × CB2 – 21.471.Conclusions: The results of this study are helpful for determining sex, even if a femur is found in a fragmented condition in the field