bluuebunny/crossref_metadata_2025 huggingface dataset:
Increasing cloudiness in Arctic damps the increase in phytoplankton primary production due to sea ice receding
Authors: Bélanger S. , Babin M. , Tremblay J.-É.
Published: June 2013

Abstract. The Arctic Ocean and its marginal seas are among the marine regions most affected by climate change. Here we present the results of a diagnostic model used to assess the primary production (PP) trends over the 1998–2010 period at pan-Arctic, regional and local (i.e. 9.28 km resolution) scales. Photosynthetically active radiation (PAR) above and below the sea surface was estimated using precomputed look-up tables of spectral irradiance, taking as input satellite-derived cloud optical thickness and cloud fraction parameters from the International Satellite Cloud Climatology Project (ISCCP) and sea ice concentration from passive microwaves data. A spectrally resolved PP model, designed for optically complex waters, was then used to assess the PP trends at high spatial resolution. Results show that PP is rising at a rate of +2.8 TgC yr−1 (or +14% decade−1) in the circum-Arctic and +5.1 TgC yr−1 when sub-Arctic seas are considered. In contrast, incident PAR above the sea surface (PAR(0+)) has significantly decreased over the whole Arctic and sub-Arctic Seas, except over the perennially sea-ice covered waters of the Central Arctic Ocean. This fading of PAR(0+) (−8% decade−1) was caused by increasing cloudiness during summer. Meanwhile, PAR penetrating the ocean (PAR(0−)) increased only along the sea ice margin over the large Arctic continental shelf where sea ice concentration declined sharply since 1998. Overall, PAR(0−) slightly increased in the circum-Arctic (+3.4% decade−1), while it decreased when considering both Arctic and sub-Arctic Seas (−3% decade−1). We showed that rising phytoplankton biomass (i.e. chlorophyll a) normalized by the diffuse attenuation of photosynthetically usable radiation (PUR), accounted for a larger proportion of the rise in PP than did the increase in light availability due to sea-ice loss in several sectors, and particularly in perennially and seasonally open waters. Against a general backdrop of rising productivity over Arctic shelves, significant negative PP trends and the timing of phytoplankton spring-summer bloom were observed in regions known for their great biological importance such as the coastal polynyas of northern Greenland.
Spores of most common airborne fungi reveal no ice nucleation activity
Authors: Pummer B. G. , Atanasova L. , Bauer H. , Bernardi J. , Druzhinina I. S. , Grothe H.
Published: June 2013

Abstract. Fungal spores are ubiquitous biological aerosols, which are considered to show ice nucleation (IN) activity. In this study the respective IN activity was tested in oil emulsion in the immersion freezing mode. The focus was laid on species of economical, ecological or sanitary significance. For the first time, not only common moulds, but also edible mushrooms (Basidiomycota, Agaricomycetes) were investigated, as they contribute massively to the total amount of fungal spores in the atmosphere. Only Fusarium avenaceum showed freezing events at low subzero-temperatures, while the other investigated fungal spores showed no significant IN activity. Furthermore, we selected a set of fungal strains from different sites and exposed them to occasional freezing stress during cultivation. Although the total protein expression was altered by this treatment, it had no significant impact on the IN activity.
Transient simulations of the carbon and nitrogen dynamics in northern peatlands: from the Last Glacial Maximum to the 21st century
Authors: Spahni R. , Joos F. , Stocker B. D. , Steinacher M. , Yu Z. C.
Published: June 2013

Abstract. The development of northern high-latitude peatlands played an important role in the carbon (C) balance of the land biosphere since the Last Glacial Maximum (LGM). At present, carbon storage in northern peatlands is substantial and estimated to be 500 ± 100 Pg C (1 Pg C = 1015 g C). Here, we develop and apply a peatland module embedded in a dynamic global vegetation and land surface process model (LPX-Bern 1.0). The peatland module features a dynamic nitrogen cycle, a dynamic C transfer between peatland acrotelm (upper oxic layer) and catotelm (deep anoxic layer), hydrology- and temperature-dependent respiration rates, and peatland specific plant functional types. Nitrogen limitation down-regulates average modern net primary productivity over peatlands by about half. Decadal acrotelm-to-catotelm C fluxes vary between −20 and +50 g C m−2 yr−1 over the Holocene. Key model parameters are calibrated with reconstructed peat accumulation rates from peat-core data. The model reproduces the major features of the peat core data and of the observation-based modern circumpolar soil carbon distribution. Results from a set of simulations for possible evolutions of northern peat development and areal extent show that soil C stocks in modern peatlands increased by 365–550 Pg C since the LGM, of which 175–272 Pg C accumulated between 11 and 5 kyr BP. Furthermore, our simulations suggest a persistent C sequestration rate of 35–50 Pg C per 1000 yr in present-day peatlands under current climate conditions, and that this C sink could either sustain or turn towards a source by 2100 AD depending on climate trajectories as projected for different representative greenhouse gas concentration pathways.
Potential effects of climate change on inundation patterns in the Amazon Basin
Authors: Langerwisch F. , Rost S. , Gerten D. , Poulter B. , Rammig A. , Cramer W.
Published: June 2013

Abstract. Floodplain forests, namely the Várzea and Igapó, cover an area of more than 97 000 km2. A key factor for their function and diversity is annual flooding. Increasing air temperature and higher precipitation variability caused by climate change are expected to shift the flooding regime during this century, and thereby impact floodplain ecosystems, their biodiversity and riverine ecosystem services. To assess the effects of climate change on the flooding regime, we use the Dynamic Global Vegetation and Hydrology Model LPJmL, enhanced by a scheme that realistically simulates monthly flooded area. Simulation results of discharge and inundation under contemporary conditions compare well against site-level measurements and observations. The changes of calculated inundation duration and area under climate change projections from 24 IPCC AR4 climate models differ regionally towards the end of the 21st century. In all, 70% of the 24 climate projections agree on an increase of flooded area in about one third of the basin. Inundation duration increases dramatically by on average three months in western and around one month in eastern Amazonia. The time of high- and low-water peak shifts by up to three months. Additionally, we find a decrease in the number of extremely dry years and in the probability of the occurrence of three consecutive extremely dry years. The total number of extremely wet years does not change drastically but the probability of three consecutive extremely wet years decreases by up to 30% in the east and increases by up to 25% in the west. These changes implicate significant shifts in regional vegetation and climate, and will dramatically alter carbon and water cycles.
Effect of foliar fertilizer and fungicidal protection against leaf spot diseases on winter wheat
Authors: Mączyńska Agnieszka , Głazek Mariola , Krzyzińska Barbara
Published: June 2013

Field experiments were carried out in the seasons 2000/2001 and 2001/2002 in Plant Protection Institute, Sooenicowice Branch to assess the influence of foliar fertilizers such as Ekolist PK 1, Ekolist Mg, Mikrosol Z and Urea on healthiness of winter wheat. Foliar fertilizers were mixed with fungicides. The fungicides were applied at full or half recommended doses. The effect of the disease on wheat leaves was evaluated three times in each vegetation season. Remaining green leaf area (GLA) of leaves was also determined. GLA of the leaves F-1 was not significantly different for each combination with different fertilization and different levels of chemical treatment. The application of foliar fertilizer only had no effect on green leaf area (GLA). The results indicate that foliar fertilization of all experimental plots improved leaf condition and therefore halted the development of wheat leaf diseases. The increases of 1000 grain mass and yield was high for each plot where a fertilizer and a full or half dose of a fungicide was applied. Foliar fertilizing with no chemical control had no proven effect on studied parameters.
Research on the development of Mycosphaerella graminicola (Fuckel) Schroeter teleomorph on wheat leaves from Poland and Czech Republic
Authors: Mirzwa-Mróz Ewa , Tvaružek Ludvik , Zamorski Czesław , Nowicki Bogdan
Published: June 2013

The aim of the work was to study the development of pseudothecia of M. graminicola. The experiment was carried out in 2002/2003. Wheat leaves collected at Kończewice (near Toruń), Słupia Wielka (near Poznań) and Kroměříź (Czech Republic) were kept on an experimental field in Warsaw. The pseudothecia were observed under the light and transmission electron microscopy. The first pseudothecia were observed on the dead leaves at the end of July. The largest number of fruiting bodies were noted in October. During the whole period of observation fruiting bodies contained asci in several stages of development. Most of them were immature. In spring the pseudothecia were not found.
Aphids (Homoptera, Aphidodea) inhabiting the shrubs of Pinus mugo Turra in the green area of Lublin. Part II. Domination and frequency of aphids, their natural enemies and the injuries caused by aphids
Authors: Sławińska Aneta , Jaśkiewicz Bożenna
Published: June 2013

Observations were conducted in the years 1999-2001 on the shrubs Pinus mugo Turra growing in the green areas of Lublin in two sites (street and park). The purpose of the studies was to establish the domination and frequency of aphids, their effect on the decorative character of shrubs and the occurrence of the aphidophagous arthropods in the aphid colonies inhabiting mountain pine. It was found out that Schizolachnus pineti F. was the dominating species in the street site (A), while Cinara pini L. dominated in the park site (B). The decorative character of shrubs was clearly lowered only by aphids S. pineti. Predatory arthropods occurred in aphid colonies inhabiting the shrubs P. mugo. Their population in both sites was low, that is why they probably had little influence on limiting the aphid population. Parasitic Hymenoptera of I and II degrees obtained from a culture of aphid mummies were more numerous in the street site.
Effects of some growing media on the growth of strawberry cvs. 'Camarosa' and 'Fern'
Authors: Ercisli Sezai , Sahin Ustun , Esitken Ahmet , Anapali Omer
Published: June 2013

This study evaluated the development of above and under ground parts of strawberry plants cvs. 'Fern' and 'Camarosa ' in a glasshouse using perlite, forest soil, finpeat, peat, finpeat+perlite (1:1) and peat+perlite (1:1) as substrates. The effects of different growing media on development of above and under ground parts of plant were statistically significant. The highest number of primary roots per plant, length of the most developed roots and number of crowns per runner were obtained from perlite, finpeat+perlite and peat medium, respectively, in both cultivars. The runner length, number of runners per plant, leaf area, fresh root weight and dry root weight varied between cultivars according to growth medium. In general peat, finpeat or finpeat+perlite gave the best results in terms of above and under ground parts of plants in both cultivars. Some important properties such as water retention capacity, cation exchangeable capacity, pH, porosity etc. of growing media using in this study were also determined.
Avena strigosa Schreb. in agrocoenoses of the Podlaski Przełom Bugu mesoregion
Authors: Skrzyczyńska Janina , Rzymowska Zofia , Stachowicz Piotr
Published: June 2013

The research on the localities of Avena strigosa and on its increased occurrence in agricultural crops of the Podlaski Przełom Bugu was carried out in 1994-1998. The documentation of this research consists of 600 phytosociological relevés and the floristic records. The paper presents the composition and structure of the field plant communities where Avena strigosa was found. It occurs frequently on various soil types of the Podlaski Przełom Bugu. However, on the area examined it was found just in small numbers, covering up to 5% of the area, while in the eastern part of the area an increase in its occurrence was observed. In the area of the Podlaski Przełom Bugu Avena strigosa occurred in spring cereals in the communities of Arnoserido-Scleranthetum and Vicietum tetraspermae as well as in the poor field communities, with the character species of Aperion spicae-venti and Panico-Setarion. Additionally, Avena strigosa was also found in the field communities of root crops belonging to Panico-Setarion alliance; however, it was present there just in small numbers.
The effect of salicylic acid and acetylsalicylic acid on red pigment formation in mechanically wounded scales of Hippeastrum x hybr. hort. and on the growth and development of Phoma narcissi
Authors: Saniewska Alicja , Horbowicz Marcin , Saniewski Marian
Published: June 2013

Various organs of Hippeastrum infected by Phoma narcissi, infested with mite, Steneotarsonemus laticeps or mechanically wounded, produce red pigment on the surface of injured tissues. The aim of the present work was to study the effect of salicylic (SA) and acetylsalicylic acids (ASA) (inhibitors of biosynthesis of jasmonates and ethylene) on red pigment formation in wounded scales of bulbs of Hippeastrum and on the mycelium growth of P. narcissi in vivo and in vitro. SA and ASA at a concentration of 1 and 2 mM partially inhibited the formation of red pigment in wounded scales, first of all in first 2 days after treatment. The growth and development of P. narcissi on basal plate and scales of longitudinally cut Hippeastrum bulb treated with SA and ASA (1 and 2 mM) was similar as in control. SA (50 µg·cm-3) and ASA (250 µg·cm-3) inhibited the mycelium growth of P. narcissi on PDA medium, and concentration of 1000 µg·cm-3 of both almost totally inhibited the mycelium growth of the pathogen. Inhibitory effect of SA and ASA on the formation of red pigment in wounded scales of Hippeastrum may be caused by lowered biosynthesis and accumulation of jasmonates.
Zbiorowiska mikroorganizmów w glebie spod leśnej uprawy żeń-szenia amerykańskiego
Authors: Pastucha Alina , Kołodziej Barbara
Published: June 2013

The investigations were carried out in 2003-2004 on American ginseng (Panax quinquefolium L.) plantation localised in the mixed forest in Trzciniec (Lubelski province). The object of the study was the soil from ginseng culture protected by the biological and chemical method. In the experiment there was also control plot - without any protection during plants vegetation. There were also analysed the infected roots of ginseng plants. Microbiological analyses showed that soil from control plots was characterised by the smallest average total number of bacteria. In 1 g of dry weight of soil after Polyversum application there was stated the highest number of bacterial colonies from Bacillus and Pseudomonas genus. The highest number of fungal colonies was obtained in 1 g of dry weight of soil on the control plots. The highest number of saprophytic fungi (including those with antagonistic character) was obtained from the soil where the biological plant protection was applied. Generally, independently of a plant protection method, American ginseng plants were affected by Alternaria alternata, Cylindrocarpon spp., Fusarium spp., Pythium irregulare and Rhizoctonia solani.
Evalution of the healthiness of winter wheat cultivated in conventional tillage, direct sowing and direct sowing with underplant crop of white clover
Authors: Moszczyńska Ewa , Pląskowska Elżbieta
Published: June 2013

Research of the healthiness of winter wheat depending on the soil tillage system and rate of nitrogen fertilization were carried out in 1998-2001. The largest threat to the healthiness of plants was tan spot, which was caused by Pyrenophora tritici-repentis, especially in cropping season 1999/2000. The soil tillage system diversified the intensification of occurence of this pathogen, only in two last years of research. The most infected by P. tritici-i was wheat, which was cultivated in the direct sowing. Application of underplant crop of white clover in the direct sowing contributed to the improvement of the plants healthiness. The highest rate of nitrogen fertilization (120 kg N.ha-1) in the highest degree favoured the damage of wheat by P. tritici-repentis, but only in two first years of research. The second pathogen Blumeria graminis, which caused powdery mildew of cereals, occured in small amount and didn't have any influence on the healthiness of winter wheat.
Stem base diseases of winter wheat grown after forecrops of the family Brassicaceae
Authors: Majchrzak Barbara , Chodorowski Bogusław , Okorski Adam
Published: June 2013

A study into the sanitary state of roots and culm base of winter wheat was carried out in 1999-2002 in the Production and Experimental Station in Bałcyny near Ostróda. Experimental wheat was cultivated after spring cross plants such as spring oilseed rape (Brassica napus ssp. oleiferus Metz.), white mustard (Sinapis alba L), chinese mustard (Brassica juncea L.), oleiferous radish (Raphanus sativus var. oleiferus L.), false flax (Camelina sativa L.), crambe (Crambe abbysinica Hoechst.) and after oats (Avena sativa L.) as a control. The other experimental factor was the method of after-harvest residue management, i.e. ploughing in the stubble, ploughing in the stubble and straw, ploughing in the stubble and straw with nitrogen added. The occurrence of root rot and stem base diseases was affected by weather conditions and forecrop species. Winter wheat roots were attacked to the lowest degree when spring rape and radish were used as forecrops, and to the highest degree - when grown after oat. The culm base was most intensely infected with fusarium foot rot (Fusarium spp.). The remaining root-rot diseases occurred every year but with different intensity. The method of utilization of after-harvest residues did not have a clear effect on the intensity of infection of the roots and culm base of winter wheat.
Sanitary state of yellow lupine (Lupinus luteus L.) in different agricultural conditions
Authors: Kurowski Tomasz P. , Bieniaszewski Tadeusz , Jaźwińska Edyta
Published: June 2013

In 1999-2001 the effect of sowing method and plant density on the sanitary state of three cultivars of yellow lupine protected with fungicides against diseases was investigated. In spring of 2000 the seedlings on the experimental fields generally withered, which was most likely caused by the applied herbicide, however in 1999 and 2001 seedling black leg (complex of fungi) was reported. The plants germinating from the seeds sown in points were clearly less attacked by pathogens evoking seedling black leg than those sown in rows. The most serious disease of yellow lupine was antracnose (Colletotrichum gloeosporioides). It occurred in all experimental years and its intensity increased during vegetation period. Cultivars of lupine used to the experiment were attacked by Colletotrichum gloeosporioides in a different degree, however, the injury index was mainly determined by weather conditions and the lupine development phase. The applied fungicides significantly limited the development of lupine antracnose. The effect of sowing method and varied plant density on disease intensity was varied.
Arbuscular mycorrhizal fungi (Glomeromycota) of soils of the Lubuskie province
Authors: Kowalczyk Sławomir , Błaszkowski Janusz
Published: June 2013

In the year 2003, the occurrence of arbuscular mycorrhizal fungi (AMF) of the phylum Glomeromycota in cultivated and uncultivated soils of the Lubuskie province was investigated. The occurrence of AMF was examined based on 56 root and rhizosphere soils collected under 7 species of cultivated and uncultivated plants growing in 28 localities. Spores of AMF were isolated from both field-collected samples and trap cultures. They were revealed in 100% of field soils and 93.8% of trap cultures and represented 7 of the 8 recognized genera of the Glomeromycota. The arbuscular fungi occurring distinctly more frequently in the soil and root samples examined were members of the genus Glomus. The species of AMF most frequently occurring in cultivated soils of the Lubuskie province were G. claroideum, G. constrictum, G. deserticola and G. mosseae, whereas G. claroideum, G. constrictum, G. deserticola, G. mosseae, and S. dipurpurescens were more frequently found in uncultivated sites. The analysis of similarity of the species composition of AMF populations in sites of the Lubuskie province and the Western Pomeranian province earlier examined showed that (1) the occurrence in Poland of most taxa of these fungi detected in the study presented here is even and does not change with time, (2) the communities of AMF area are stable, despite the arduousness resulting from the agricultural and chemical practices conducted, and (3) the species diversity of the plants cultivated in a long period of time has no influence on the species composition of populations of AMF.
Study of Interrelation Between Reaction of Polymer-Bound/Blend Photoacid Generator with Solvated Electron and Acid Generation Efficiency
Authors: Enomoto Satoshi , Nguyen Dang Tuan , Tagawa Seiichi
Published: June 2013

Polymer-bound photoacid generators (PAGs) (anion bound) and their corresponding polymers were synthesized for evaluation of the reactivity of polymer-bound PAGs with secondary electrons in solutions by the electron beam pulse radiolysis method. In the solutions, the rate constants of polymer-bound PAGs are much lower than those of polymer-blend PAGs. In addition, we evaluated the acid generation efficiencies of polymer-bound PAGs. As a result, despite the film state, the acid generation efficiency of polymer-bound PAGs are about 10% lower than those of the polymer-blend PAGs. These differences are explained by the difference in stabilization effects between polymer-bound PAGs and polymer-blend PAGs in both solutions and films.
In situ Nondestructive Impedance Spectroscopic Study of Nanostructured Heterojunction Organic Photovoltaic Cells
Authors: Ryuzaki Sou , Onoe Jun
Published: June 2013

The equivalent circuit model of the heterojunction organic photovoltaic (OPV) cells consisting of 20-nm-thick zinc-octaethylporphyrin [Zn(OEP)] and 30 nm-thick C60 films respectively used as donor and acceptor layers has been determined using impedance spectroscopy under dark and illumination (100 mW/cm2, AM1.5) conditions. Under dark condition, the equivalent circuit consisting of a series resistance and two-R
C (R: resistance, C: capacitance) circuits corresponding to individual layers well reproduced the impedance spectra. On the other hand, the four-R
C circuit model, in which the additional two R
C circuits corresponded to individual films in the vicinity of the Zn(OEP)/C60 interface, could explain the impedance spectra obtained under illumination condition.
Water Trapping at the Graphene/Al2O3 Interface
Authors: Cho Sung Beom , Lee Sangho , Chung Yong-Chae
Published: June 2013

We investigated the effects of trapped water at the graphene/Al2O3 interface using density functional theory. We found that molecularly trapped water does not induce serious interbanding at the Dirac point. However, dissociatively trapped water induces serious interbanding at the Dirac point because of the band alignment induced by the local field of the hydroxyl groups. These findings indicate that trapped water at the graphene/Al2O3 interface can have a significant effect on the electronic structure of graphene.
Gate Structure Dependence of Variability in Polycrystalline Silicon Fin-Channel Flash Memories
Authors: Liu Yongxun , Kamei Takahiro , Matsukawa Takashi , Endo Kazuhiko , O'uchi Shinichi , Tsukada Junichi , Yamauchi Hiromi , Ishikawa Yuki , Hayashida Tetsuro , Sakamoto Kunihiro , Ogura Atsushi , Masahara Meishoku
Published: June 2013

Polycrystalline silicon (poly-Si) fin-channel tri-gate (TG)- and double-gate (DG)-type flash memories with a thin n+-poly-Si floating gate (FG) and different control-gate (CG) lengths (L
CG's) from 76 to 256 nm have been fabricated and their electrical characteristics including statistical threshold voltage (V
t) and subthreshold slope (S-slope) have been comparatively investigated before and after one program/erase (P/E) cycle. It was experimentally found that better short-channel effect (SCE) immunity, a smaller V
t variation, and a higher program speed are obtained in TG-type flash memories than in DG-type memories. The higher performance of TG-type flash memories is contributed by the additional top gate and recessed bottom silicon dioxide (SiO2) regions, which strengthen the controllability of the channel potential and increase the coupling ratio of the FG to the CG. Therefore, the developed poly-Si fin-channel TG structure is expected to be very useful for the fabrication of high-density and low-cost flash memories.
Effects of Hydrogen and Nitrogen Atmospheres on Growth of Ultrananocrystalline Diamond/Amorphous Carbon Composite Films by Reactive Pulsed Laser Deposition
Authors: Al-Riyami Sausan , Shaban Mahmoud , Gima Hiroki , Yoshitake Tsuyoshi
Published: June 2013

The growth of ultrananocrystalline diamond/nonhydrogenated amorphous carbon composite films was realized by pulsed laser deposition with a graphite target in a nitrogen atmosphere totally excluding hydrogen. The existence of 7 nm diamond grains was confirmed by X-ray diffraction. Nitrogen incorporation into the films was confirmed by X-ray photoemission and near-edge X-ray absorption structure spectroscopies, and the nitrogenation produced n-type conduction with an electrical conductivity of 0.2 Ω-1· cm-1 at 300 K. The results of study proved that nitrogen acts as a reactive gas for the formation of diamond grains, similarly to hydrogen.
Synthesis and Characterization of La0.5Sr0.5TiO3Nanopaticles Prepared by Thermal Decomposition
Authors: Wannasen Likkhasit , Swatsitang Ekaphan
Published: June 2013

La0.5Sr0.5TiO3(LSTO) nanoparticles were synthesized by thermal decomposition using La(acetate)-C6H9LaO6·H2O, Sr(acetate)-(CH3CO2)2Sr and C6H28O6Ti as staring materials. The precursor was calcined at 600, 700, 800, and 900 °C for 3 h in Ar. X-ray diffraction (XRD) results show that the crystalline phase of the perovskite structure starts to be formed at 600 °C with the particle sizes in the range of ∼29–39 nm. Transmission electron microscope (TEM) bright-field images show the agglomeration of LSTO nanoparticles with particle size in the same range as reveal by scanning electron microscope (SEM). Selected-area electron diffraction (SAED) patterns indicate that increasing the calcination temperature can increase the crystallinity of the nanoparticles. Optical absorption measurements show the decrease of the energy band gap with increasing calcination temperature. The magnetization measurements indicate that all of the samples are paramagnetic.
Strong Adhesion of Silver/Polypyrrole Composite onto Plastic Substrates toward Flexible Electronics
Authors: Kawakita Jin , Hashimoto Yasuo , Chikyow Toyohiro
Published: June 2013

Flexible electronics require sufficient adhesion to substrates, such as a plastic or a polymer, of the electric wiring for devices. A composite of a conducting metal and a polymer is a candidate alternative to pure metals in terms of wire flexibility. The purpose of this study was to evaluate the adhesiveness of a silver/polypyrrole composite to plastic substrates and to clarify the mechanism of adhesion. The composite was prepared on various plastic substrates by dropping its fluid dispersion. Its adhesiveness was evaluated by the peel-off test and its interfacial structure was characterized by microscopy measurements. Some polymers including Teflon with generally weak adhesion to different materials showed a high adhesiveness of more than 90%. The strong adhesion was related to the anchoring effect of the composite penetrating into the pores near the surface of the substrate.
Light Output Improvement of GaN-Based Light-Emitting Diodes Using Hydrothermally Grown ZnO Nanotapers
Authors: Tu Yung-Chun , Wang Shui-Jinn , Lin Jia-Ching , Tsai Fu-Shou , Lin Tseng-Hsing , Uang Kai-Ming , Chen Tron-Min
Published: June 2013

A new two-step hydrothermal growth (HTG) process with a shorter processing time and better growth control is proposed for the synthesis of ZnO nanotapers (NTs). The application of HTG ZnO NTs as surface roughening nanostructures to improve the light output power (Lop) of GaN-based LEDs is demonstrated. Compared with that of ZnO nanowires, the use of ZnO NTs leads to an improvement inLopby 24.5% at 350 mA, which could be attributed to the fact that tapered ends of ZnO NTs offer more constructive photon scattering to maximize light extraction.
Photothermal Actuation of Cantilevered Multiwall Carbon Nanotubes with Bimaterial Configuration toward Calorimeter
Authors: Hiroshima Seiya , Yoshinaka Atsushi , Arie Takayuki , Akita Seiji
Published: June 2013

We investigated the bimaterial effect on a multiwall carbon nanotube (CNT) cantilever by means of a photothermal actuation method toward sensitivity enhancement for calorimetry. The coating of a 10-nm-thick Ti layer on top of the CNT cantilever of 50 nm diameter successfully enhanced the photothermal vibration amplitude by 10–50 times. This implies that the expected resolution for the heat capacity measurement is as high as ∼0.1 fJ/K on the base of a simple lumped model for the photothermally excited Ti-coated CNT cantilever.
Novel Heterostructured Organic Photovoltaics Formed by Multilayered Direct Nanoimprinting
Authors: Tomohiro Kohei , Tada Kazuhiro , Ishikawa Manabu , Fujita Honoka , Nishikura Naoki , Kawata Hiroaki , Hirai Yoshihiko
Published: June 2013

Multilayered direct nanoimprint is proposed to expand the heterojunction area of an organic solar cell without demolding using a built-in electrode mold. The mold is directly imprinted onto a conventional multilayered planar [poly(3-hexylthiophene) (P3HT)/[6,6]-phenyl-C61-butyric acid methyl ester (PCBM)] heterostructure. The P3HT layer is lifted into the PCBM layer and the boundary of the junction area is successfully expanded, as investigated by simulation. The improvement in the short-circuit current of the photovoltaics as a result of adopting the nanoimprinted device is observed to be approximately 20% compared with planar heterostructured devices without nanopatterns formed under an equivalent sequence.
Uniform Residual Layer Creation in Ultraviolet Nanoimprint Using Spin Coat Films for Sub-100-nm Patterns with Various Pattern Densities
Authors: Suzuki Kenta , Youn Sung-Won , Wang Qing , Hiroshima Hiroshi , Nishioka Yasushiro
Published: June 2013

In the case of spin coat films, the variation in residual layer thickness (RLT) caused by the variation in pattern density is a problem encountered in UV nanoimprint lithography (NIL). To solve this problem, we proposed the use of capacity-equalized molds in which pattern depths are modified to equalize pattern capacity per unit area at any location. Although the effectiveness of these molds was validated using molds with various pattern sizes of the order of hundreds of micrometers, the dimensions in those cases were large and the aspect ratios were far too small in comparison with the values that would be required in the device patterns to be fabricated by nanoimprinting. In this study, we evaluate the applicability of using a capacity-equalized mold with nanometer-scale patterns. A capacity-equalized mold with two-step-depth structures and sub-100-nm wide patterns was successfully fabricated as designed while maintaining the groove width. By using a capacity-equalized mold, the standard deviation of RLT of UV-nanoimprinted patterns can be reduced to less than one-third of that obtained using a conventional mold. The UV-nanoimprinted patterns using a capacity-equalized mold were uniformly transferred onto a Si substrate.
Rapid and Sensitive Detection of Brain-Derived Neurotrophic Factor with a Plasmonic Chip
Authors: Tawa Keiko , Satoh Mari , Uegaki Koichi , Hara Tomoko , Kojima Masami , Kumanogoh Haruko , Aota Hiroyuki , Yokota Yoshiki , Nakaoki Takahiko , Umetsu Mitsuo , Nakazawa Hikaru , Kumagai Izumi
Published: June 2013

Plasmonic chips, which are grating replicas coated with thin metal layers and overlayers such as ZnO, were applied in immunosensors to improve their detection sensitivity. Fluorescence from labeled antibodies bound to plasmonic chips can be enhanced on the basis of a grating-coupled surface plasmon resonance (GC-SPR) field. In this study, as one of the representative candidate protein markers for brain disorders, the brain-derived neurotrophic factor (BDNF) was quantitatively measured by sandwich assay on a plasmonic chip and detected on our plasmonic chip in the concentration of 5–7 ng/mL within 40 min. Furthermore, BDNF was detected in the blood sera from three types of mice: wild-type mice and two types of mutant mice. This technique is promising as a new clinical diagnosis tool for brain disorders based on scientific evidence such as blood test results.
pH Sensor Based on Chemical-Vapor-Deposition-Synthesized Graphene Transistor Array
Authors: Zaifuddin Nursakinah Mohd , Okamoto Shogo , Ikuta Takashi , Ohno Yasuhide , Maehashi Kenzo , Miyake Masato , Greenwood Paul , Teo Kenneth B. K. , Matsumoto Kazuhiko
Published: June 2013

We have successfully fabricated a pH-sensor array based on chemical-vapor-deposition (CVD)-synthesized graphene. As large-scale monolayer graphene is synthesized by this method, the size and the position of graphene can be controlled. Therefore, after transferring graphene onto SiO2/Si substrates, a graphene field-effect transistor (FET) array was produced. The sensing characteristics of the CVD-synthesized graphene-based device were investigated using three buffer solutions with different pH values (pHs 4.0, 6.8, and 9.3). The electrical measurements reveal that for most of the graphene FETs in the array, a similar stepwise increment in drain current was observed upon the introduction of each buffer solution with increasing pH value sequence. This will lead to the realization of the fabrication of multiplex hand-held chemical and biological sensors based on CVD-synthesized graphene.
An Electrostatically Driven Double-Sided One-Chamber Peristaltic Pump with Four Electrodes
Authors: Kim Bonghwan , Lee Ki Sung , Shannon Mark A.
Published: June 2013

A double-sided peristaltic micropump driven by electrostatic actuation has been developed for pumping gases through microsystems, such as a micro-gas chromatography system. The pump was operated from 60 to 160 V. The maximum flow rate of 389 µl/min was achieved at 100 V and 4 Hz with an estimated power consumption of 26 µW/sccm. In order to increase the flow rate, a double-sided chamber design was used. The micropump had two single-sided silicon chambers and a membrane in the middle of the pump chamber. The peristaltic micropump has one long chamber and a metalized membrane which can divide the chamber into four small chambers during operation. The micropump was operated with four electrodes in the membrane and a four-phase sequencing actuation.
Fabrication of Silicon Pyramid-Nanocolumn Structures with Lowest Reflectance by Reactive Ion Etching Method
Authors: Kong DaeYoung , Oh JungHwa , Pyo Daeseung , Kim Bonghwan , Cho ChanSeob , Lee JongHyun
Published: June 2013

We have developed nanosized structures on a silicon surface by the reactive ion etching method. The purpose of this work is to fabricate pyramid-nanocolumn structures for crystalline silicon solar cells using a reactive ion etching (RIE) system with a metal mesh and to simulate surface texturing structures using the PC1D program. The reflectance of the structures was lower than that of only-pyramid or only-nanocolumn structure arrays. We formed micropyramids by general anisotropic saw damage removal (SDR) etching using potassium hydroxide (KOH) solution, as well as nanocolumn structures by RIE with a metal mesh and SF6/O2 gas (35/30 sccm). We studied the fundamentals and morphologies of structures (micropyramids, nanocolumn structures, and pyramid-nanocolumn structures). Owing to anisotropic SDR etching in KOH solution for a single-crystalline silicon wafer, the whole wafer surface is covered with pyramid structures with a size range of 1–5 µm. After RIE texturing, nanocolumn structures with a size range of 20–50 nm were formed on the pyramid structures. Owing to binary surface texturing with pyramid and nanocolumn structures, spectra with weighted average reflectances below 3% in the wavelength range from 350 to 1100 nm were obtained under optimized condition. In particular, the average reflectance was 1.16% in the wavelength range of 400 to 1000 nm without an antireflection coating (ARC). The combination of the pyramid and nanostructures has a very low reflectance. Therefore, ARC is not required in the solar cell process in the case of using pyramid-nanocolumn structures.
A Hardware-Oriented Finite-Difference Time-Domain Algorithm for Sound Field Rendering
Authors: Yiyu Tan , Inoguchi Yasushi , Sato Yukinori , Otani Makoto , Iwaya Yukio , Matsuoka Hiroshi , Tsuchiya Takao
Published: June 2013

Sound field renderings are data-intensive and computation-intensive applications. An alternative solution is to directly implement sound field rendering algorithms by using hardware. In this paper, a hardware-oriented finite-difference time-domain (FDTD) algorithm named HO-FDTD is proposed for sound field rendering, which has no complex operations involved, and consumes small hardware resources. In a sound space with 32,768 elements surrounded by rigid walls, the hardware simulation results are in good agreement with the software simulation results except for the one-cycle delay. In the software simulation, when the element scale is 32×32×32 and the time steps are 20,000, the HO-FDTD speeds up computations by 19% against the updated digital Huygen's model (DHM) and Yee-FDTD, and by 132% against the original DHM. Compared with the software simulation, the hardware systems with the parallel architecture and the time-sharing architecture enhance their calculation performance significantly in the case of different element scales, and provide a higher data throughput.
Micro-Energy Harvesters Integrated with a Quatrefoil-Shaped Proof Mass Suspended by Multiple (K,Na)NbO3Beams
Authors: Minh Le Van , Hara Motoaki , Kuwano Hiroki
Published: June 2013

In this study, we developed an energy harvester with a multibeam structure employing a (K,Na)NbO3(KNN) thin film. The harvester had a quatrefoil-shaped proof mass suspended by four KNN beams and was completely fabricated by micromachining technologies. The harvester was designed to obtain high nonlinearity. As a result, the fractional bandwidth of operable frequency was widened by more than 40% when the acceleration was 15 m/s2. The maximum harvested power of 640 nW was obtained at the resonant frequency of 1412 Hz.
Measurement of Plasma Clotting Using Shear Horizontal Surface Acoustic Wave Sensor
Authors: Nagayama Tatsuya , Kondoh Jun , Oonishi Tomoko , Hosokawa Kazuya
Published: June 2013

The monitoring of blood coagulation is important during operation. In this study, a shear horizontal surface acoustic wave (SH-SAW) sensor is applied to monitor plasma clotting. An SH-SAW sensor with a metallized surface for mechanical perturbation detection can detect plasma clotting. As plasma clotting is a gel formation reaction, the SH-SAW sensor detects viscoelastic property changes. On the other hand, an SH-SAW sensor with a free surface for electrical perturbation detection detects only the liquid mixing effect. No electrical property changes due to plasma clotting are obtained using this sensor. A planar electrochemical sensor is also used to monitor plasma clotting. In impedance spectral analysis, plasma clotting is measured. However, in the measurement of time responses, no differences between clotting and nonclotting are obtained. Therefore, the SH-SAW sensor is useful for monitoring plasma clotting.
Analysis of Mass Loading Effect on Guided Shear Horizontal Surface Acoustic Wave on Liquid/Au/Quartz Structure for Biosensor Application
Authors: Goto Mikihiro , Yatsuda Hiromi , Kondoh Jun
Published: June 2013

A numerical analysis of a shear horizontal surface acoustic wave (SH-SAW) immunoassay biosensor has been investigated. The numerical calculation method proposed by Campbell and Jones has generally been used to calculate SAW propagation characteristics. In this paper, a numerical calculation method for SH-SAW propagation characteristics, which is a modified method of Campbell and Jones involving the effect of liquid viscosity is applied to quartz. A mass loading sensitivity of a 250 MHz SH-SAW delay-line biosensor was calculated and compared with the experimental results. It can be concluded from the results that viscosity sensitivity is dominant over mass loading sensitivity for 250 MHz SH-SAW biosensors.
Detection of Arterial Wall Boundaries Using an Echo Model Composed of Multiple Ultrasonic Pulses
Authors: Ibrahim Nabilah , Hasegawa Hideyuki , Kanai Hiroshi
Published: June 2013

The assessment of the intima-media thickness (IMT) of the carotid arterial wall, which is the most frequently used indicator to diagnose atherosclerosis by ultrasound, involves the measurement of the lumen-intima boundary (LIB) and media-adventitia boundary (MAB). In this study, using the mean squared error (MSE) method and by applying the template matching technique, an adaptive model of an ultrasonic echo, which is obtained from an ultrasonic pulse measured with a hydrophone, was fitted with the measured in vivo RF echo to estimate the boundaries of the carotid arterial wall. In the present study, the frequency and phase of the adaptive model were considered to improve the accuracy in the determination of the LIB and MAB. For a 7.5-mm-long short segment of the carotid artery in the longitudinal direction, the average IMTs estimated by the improved technique and the previous method were 502±61 and 558±120 µm, respectively, showing a decrease in the standard deviation by the proposed method. Moreover, the result obtained by the improved technique presented only 0.4% difference between the automatically detected boundary and the manually detected boundary, which is smaller than that obtained by the previous method (10.7% difference). These results verified that the boundary detected by the improved technique was more accurate than that detected by the previous method.
Relationship between Spatial Distribution of Noise Sources and Target Scatterings Observed in the 2010 Sea Trial of Ambient Noise Imaging
Authors: Mori Kazuyoshi , Ogasawara Hanako , Nakamura Toshiaki , Tsuchiya Takenobu , Endoh Nobuyuki
Published: June 2013

An aspherical lens with an aperture diameter of 1.0 m has been designed and fabricated to develop a prototype system for ambient noise imaging (ANI). A sea trial of silent target detection using the prototype ANI system was conducted under only natural ocean ambient noise at Uchiura Bay, in November of 2010. It was verified that the targets are successfully detected under natural ocean ambient noise, mainly generated by snapping shrimps. In this study, we surveyed the relationship between the spatial distribution of noise sources and the target scattering captured by the ANI system. The observation using a pair of tetrahedron arrays was conducted at the same time as the sea trial. The estimated source positions were spread when the noises arrived from the sea bottom. Some of the sources were around the barge, and other sources were around fish preserves. On the other hand, the source positions were coincident with the barge when the noises arrived from the sea surface. The calculated scattering fields of the target showed sharp directivities. The locations of noise sources, where the ANI system can capture target scatterings with high intensities, were roughly determined at the barge around the sea surface.
200-mm GaN-on-Si Based Blue Light-Emitting Diode Wafer with High Emission Uniformity
Authors: Nishikawa Atsushi , Groh Lars , Solari William , Lutgen Stephan
Published: June 2013

We investigated the emission wavelength uniformity of 200-mm GaN-on-Si based blue light-emitting diode (LED) wafer grown by metalorganic vapor phase epitaxy (MOVPE). The larger the Si substrate diameter becomes, the more difficult to obtain uniform distribution of the emission wavelength because of the larger bow during growth, resulting in larger on-wafer inhomogeneity in growth temperature. Owing to the GaN-on-Si buffer strain management, optimized gas flow condition, and precise control of temperature balance in a reactor, we have achieved high thickness and crystal quality uniformity over the 200-mm GaN-on-Si based blue LED wafer. As a result, excellent blue photoluminescence emission wavelength uniformity from the InGaN-multi-quantum wells can be demonstrated on a 200-mm wafer with a standard deviation of 2.53 nm (0.57%). Less wavelengths binning with these highly uniform emission over the 200-mm wafer show the capability of sustainable cost reduction in LED fabrication based on GaN-on-Si technology.
Photoluminescence of Single GaN/InGaN Nanorod Light Emitting Diode Fabricated on a Wafer Scale
Authors: Chan Christopher C. S. , Zhuang YiDing , Reid Benjamin P. L. , Jia Wei , Holmes Mark J. , Alexander-Webber Jack A. , Nakazawa Shingo , Shields Philip A. , Allsopp Duncan W. E. , Taylor Robert A.
Published: June 2013

Nanorod arrays were fabricated on a blue InGaN/GaN single quantum well (QW) LED wafer using nanoimprint lithography. A regular hexagonal lattice of nanorods was made at a pitch of 2 µm producing single quantum disks in the nanorods with diameter of ∼400 nm. Time integrated micro-photoluminescence was performed to investigate the emission properties of top down processed single nanorods at 4.2 K. Micro-photoluminescence maps were made to study the spatial isolation of the photoluminescence emission, showing a good contrast ratio between nanorods. Excitation power dependent studies show screening of the quantum confined Stark effect for both the unprocessed wafer and the single nanorod. At low excitation powers, localised states appearing as sharp peaks in the photoluminescence spectrum were visible with a density of approximately four peaks per nanorod.
Electronic Structure and Spontaneous Polarization in ScxAlyGa1-x-yN Alloys Lattice-Matched to GaN: A First-Principles Study
Authors: Shimada Kazuhiro , Chichibu Shigefusa F. , Hata Masahiro , Sazawa Hiroyuki , Takada Tomoyuki , Sota Takayuki
Published: June 2013

We performed first-principles calculations of the spontaneous polarization and electronic band structures in ScxAlyGa1-x-yN alloys assuming their growth on freestanding GaN. We found an apparent deviation from the Vegard's law of the lattice constants of the ScxAlyGa1-x-yN alloys lattice-matched to GaN. It was supposed that this deviation comes from the different bonding properties of IIIB and IIIA nitrides, resulting in different crystal structures, such as hexagonal and wurtzite structures. As was reported in our previous report on YxAlyGa1-x-yN [K. Shimada et al.: J. Appl. Phys. 110 (2011) 074114], we also found that in ScxAlyGa1-x-yN alloys, the superlattice-like structure of Sc atoms reduced the magnitude of spontaneous polarization [K. Shimada et al.: Semicond. Sci. Technol. 27 (2012) 105014]. The magnitude of the spontaneous polarization of ScxAlyGa1-x-yN is larger than that of YxAlyGa1-x-yN in a wide mole fraction range of Ga. We found the nonlinearity and dependence of the atomic arrangement of Sc in the alloys. The band-gap energies at Γ have the same characteristics as the spontaneous polarization. The band-gap energies of ScxAlyGa1-x-yN are also larger than those of YxAlyGa1-x-yN in the wide mole fraction range of Ga. The band structures of ScxAlyGa1-x-yN have a direct gap at Γ and form a flat band around the valence band top originating from the hybridization of the Sc 3d and N 2p electrons.