bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stable Positions of a Metal Ion Relative to an Icosahedral Borane
Authors: Beckel C. L. , Howard I. A. 
Published: March 2011

ABSTRACTWe have considered a series of conformations of the neutral complex [Mg+B12H12] including those in which the Mg is internal to the icosahedral B12 cage. Self-consistent molecular-orbital calculations to determine the total cluster energy have been carried out as the Mg atom is moved from the center of the borane to a position 10Å from the center (outside the borane cage). Two energy minima are found as a function of position. One is outside the borane cage. at 3.0–3.5Å from the center; the second is at the center of the borane cage. The central minimum is the deeper of the two if Mg 3d orbitals are included in the basis set.Many atoms have a low ionization energy and are, as ions, of appropriate “size” to fit inside a B12 cage. Incorporation of such ions into B12 cages in solids may offer significant flexibility in the development of refractory semiconductors and thermoelectrics.
Thermal Properties of Boron-Rich Borides
Authors: Fischer H. E. , Swartz E. T. , Türkes P. R. H. , Pohl R. O. 
Published: March 2011

ABSTRACTThe specific heats of β-B and of B4C have been reviewed, and measurements of a different sample of B4C have been carried out below 80 K. A specific heat anomaly observed previously in boron carbides has been shown to be extrinsic in origin. The thermal conductivity of B1−x Cx, for x < 0.20, between 0.2 and 2000 K has also been reviewed, and recent measurements have been added. The magnitude and temperature dependence of the conductivity are somewhat similar to what is expected for amorphous boron, except for the characteristic plateau which is not clearly discernible. A possible explanation for the strong phonon scattering is discussed.
Thermal Conductivity of Boron Carbides
Authors: Moss Marvin 
Published: March 2011

ABSTRACTThe thermal conductivity, k, of boron carbides of various B/C ratios, two modes of preparation – hot pressed and carbothermic, and two isotopic variants of boron – 11B and normal boron 10.81B, was measured from 300 to 1023 K. The density and composition of the samples were reflected in the magnitude and temperature dependence of k, and were investigated further with scanning electron microscopy, Rutherford backscattering spectroscopy, and Raman spectroscopy. While lower than theoretical density in B4C reduces k, the characteristic monotonic decline of k with increasing temperature is retained. This k-vs.-T behavior distinguishes B4C from material with larger B/C ratios for which the temperature dependence is essentially nil.
Laser Induced Fluorescence and Optical Emission Studies of Fluorocarbon Plasmas
Authors: Booth J. P. , Hancock C. , Perry N. D. , Blaikleye D. C. W. , Cairns J. A. , Smailes R. 
Published: March 2011

ABSTRACTLaser induced fluorescence of CF2 has been observed in plasmas of CF4 and its mixtures with O2 and H2. Surface removal rates of the radical in pure CF4 were measured by observing the decay of the radical when the plasma is switched off. The reduction in CF2 concentration, and the increase in F atom concentrations (the latter measured by optical emission spectroscopy) on the addition of O2 is reproduced by a model of the plasma in which gas phase chemical reactions play a dominant role. The increase in CF2 concentration on the addition of H2 to a CF4 plasma is shown to be due to a reduction in the surface removal rate.
Plasma Diagnostics for a Low-Pressure Plasma Spray Deposition System
Authors: Weissman Suzanne H. , Smith Mark F. , Chambers William B. 
Published: March 2011

ABSTRACTPlasma temperatures and spray particle velocities were measured in a low pressure plasma spray system. Plasma temperatures of 6,540–9,050 K were calculated from argon atomic emission spectra by the Boltzmann slope method. Peak particle velocities up to 365 m/s were measured with a laser velocimeter for 44 pm Al2O3, spray powder. Measured particle velocity distributions show a strong dependence on process chamber pressure over the range of 50–600 Torr.
Large Area Electron Beam Enhanced Reactive Etching of SiO2
Authors: Boyer P. Kirk , Verhey Tim , Rocca Jorge J. 
Published: March 2011

ABSTRACTA large area (2.8 cm2) electron beam source has been developed, characterized, and applied to anisotropic etching of SiO2 masked with photoresist. This beam operates at high pressures (up to 100 mTorr), in reactive gases, and at more than 10 mA/cm2. Beam current can be controlled in several ways independently from beam energy. The 100 – 900 eV low energy beam propagates with collimation through several cm of reactive gas, and is believed to minimize space charge defocusing by collisionally ionizing the working gas.
Mechanism of the Slow-Down of the Silicon Etch Rate by a Fluorocarbon Overlayer in CF4/H2 Reactive Ion Etching of Silicon
Authors: Oehrlein Gottlieb S. , Robey Steve W. , Jaso Mark A. 
Published: March 2011

ABSTRACTWe have utilized an ultrahigh vacuum surface analysis system interfaced via a load-lock to a flexible diode dry etching apparatus to study vacuum transferred CF4/H2 reactive ion etched silicon surfaces by X-ray photoemission spectroscopy (XPS). From the observation and analysis of silicon-fluorine bonding underneath the fluorocarbon film and the dependence of the abundance of fluorosilyl species on the thickness of the fluorocarbon overlayer, the role of the fluorocarbon film in the slow-down of the Si etch rate has been elucidated: The role of the fluorocarbon film is to “protect” the Si surface from attack of fluorine, rather than prevent the escape of SiF4 etch product.
High Quality Deposition of SiO2 Downstream from a Microwave Discharge
Authors: Robinson B. , Hoh P. D. , Madakson P. , Nguyen T. N. , Shivashankar S. A. 
Published: March 2011

ABSTRACTHigh quality stoichiometric silicon dioxide films have been deposited on silicon substrates at low pressure(1.0Torr) and low temperatures(≤ 350C) downstream and at a right angle to a microwave discharge. The deposition was accomplished by injecting 2% SiH4 in helium downstream of a N20 microwave generated discharge. Infrared spectroscopic analysis has determined that no detectable SiH, SiOH, Si-H2o or SiN chemical complexes were present in any films deposited at temperatures above 250C. Rutherford Backscattering and Forward Scattering Detection Spectroscopy were used to determine the elemental composition and hydrogen concentration in the films, respectively. The thick films were found to be stoichiometric with no detectable elemental impurities. The measured hydrogen concentration in the thin films was comparable to that measured in thermally grown Si0 2 of approximately the same thickness. The quality of the thin oxides(<30nm) has been determined by fabricating MOS devices from the Si-Si0 2 system.
Plasma Deposited Ni-Al-Mo Metal-Metal Composites
Authors: Jackson M. R. , Siemers P. A. 
Published: March 2011

ABSTRACTSix different composite microstructures were produced by low pressure plasma deposition of γ/γ'-α Ni-Al-Mo materials. Interlaminate spacing, volume fraction of α Mo, and continuity of the laminate structure were varied. Thermal expansion behavior (25–1250°C), density, and room temperature elastic modulus were correlated with volume fraction of α Mo. Tensile ductility (25–960°C) was correlated with both volume fraction and distribution of the α Mo phase, while yield strength was nearly insensitive to composite structure. Composite strengths were greater than were the unreinforced matrix strengths.
Estimation of Ion Impact Energies and Electrode Self-Bias Voltage in Capacitive RF Discharges
Authors: Savas S. E. 
Published: March 2011

ABSTRACTThe dependences of the electrode self-bias voltage and the ratio of ion energies on electrode area ratio are calculated for a model of capacitively coupled rf discharges. It is assumed that concentric spherical elecrodes with fluid-like radial ion flow adequately models the ion motion, that sheath impedances are dominant, and that ionization processes in the glow are due to ohmically heated electrons. Results show that the ratio of ion energies impacting the smaller electrode to those on the larger depends on the ratio of electrode areas in a more complex manner than a power law.The reason for this is that sheath impedances are more resistive or capacitive at different times in the rf cycle. The self-bias ratio is found to depend relatively little on the ionization model or the pressure but differs substantially from the “power law” result. The agreement of measurements with the model is fairly good.
Reduction of Selected Metal Oxides in a Thermal Plasma Produced by a Nontransferred ARC Torch
Authors: Detering Brent A. , Batdorf James A. , Wai Chien M. 
Published: March 2011

ABSTRACTPlasma flow field temperatures are determined in a nontransferred arc plasma using emission spectroscopy. This technique is then utilized to identify thermal decomposition and reduction products produced in the plasma plume when metal oxide particles are injected into the plasma arc. The processed particles are then studied using AAS, SEM, EDS and XRD to characterize the chemical changes that have occurred in the particles. A Fourier transform method is used to study changes in particle morphology.
The Effects of Gas Composition and Pressure on RF Plasma Sintering of MgO
Authors: Kong Peter C. , Lau Y. C. , Pfender E. 
Published: March 2011

ABSTRACTRapid densification of MgO in an rf plasma without sintering aids is demonstrated. The sintered densities of MgO are sensitive to the plasma composition and gas pressure. In general, specimens are sintered to higher densities in Ar/O2 and Ar/H2O plasmas than in pure Ar plasmas. This may be explained by the effects of plasma enthalpy and surface recombination of charged particles and of atomic species. Analyses show that the evolution of the microstructures of the sintered specimens remains similar, regardless of the plasma conditions. No substantial grain growth is observed.
A Method for Non-Intrusively Determining ion Impact Current Density and Energy Distribution in Capacitively Coupled RF Plasmas
Authors: Savas S. E. 
Published: March 2011

ABSTRACTThe dependence of ion current density on the sheath voltage and thickness, and ion energy distributions as functions of the pressure and sheath voltage amplitude have been calculated using a self-consistent computer code, ISHEATH. The current density is found to obey an approximate power law dependence on the amplitude of the sheath voltage, Vs, and the sheath thickness, d, and, when charge exchange collisions are considered, on the collision parameter α ΞNgas · σcx ·d. The ion energy distribution (IED) is found to mainly depend on α: for α ≃l there is only a slight (≃10%) change from the collisionless case; for a ≤ 10 the IED is peaked at an energy which is much less than the time-average sheath potential.
Bambusicaliscelis, a New Bamboo-Feeding Planthopper Genus of Caliscelini (Hemiptera: Fulgoroidea: Caliscelidae: Caliscelinae), with Descriptions of Two New Species and Their Fifth-Instar Nymphs from Southwestern China
Authors: Chen Xiang-Sheng , Zhang Zheng-Guang 
Published: March 2011

AbstractBambusicaliscelis Chen & Zhang gen. nov. (Hemiptera: Fulgoroidea: Caliscelidae: Caliscelinae: Caliscelini) is established to accommodate two new species, Bambusicaliscelis fanjingensis Chen & Zhang, sp. nov. (type species, Guizhou, southwestern China) and B. dentis Chen & Zhang, sp. nov. (Guizhou, southwestern China). Members of the new genus are known to feed exclusively on bamboo (Poaceae: Bambusoideae) and represent the first record of bamboo-feeding planthopper Caliscelidae in China. The main morphological features, male genitalia, and the fifthinstar nymphs of two new species are described and illustrated. In addition, photographs and a key for identifying the adults and fifth-instar nymphs of the genus Bambusicaliscelis are provided. The importance of those groups as a pest on bamboo is discussed briefly. Biological notes and a discussion of those groups' distribution are given.
Seasonal Abundance of the Nearctic Gall MidgeObolodiplosis robiniaein Italy and the Impact of Its AntagonistPlatygaster robiniaeon Pest Populations
Authors: Duso C , Boaria A , Surian L , Buhl P N 
Published: March 2011

AbstractThe Nearctic gall midge Obolodiplosis robiniae (Haldeman, 1847) (Diptera Cecidomyiidae) infesting black locusts, Robinia pseudoacacia L. (Fabaceae), was detected in Asia in 2002 and in Europe (first in Italy) in 2003. Its distribution in Europe has expanded dramatically, probably favored by extensive distribution of its host plant along the main routes. The results of a 3-yr study on the seasonal abundance of O. robiniae in northern Italy are reported here. O. robiniae can develop three to four generations per year by exploiting plants of different ages and vigor. Overwintering takes place as diapausing larvae and adults emerge in spring. Two generations are completed on mature plants where populations decline in summer. Two additional generations can develop on root suckers from midsummer onward. Pest population densities reach their highest levels in late spring. Gall midge larvae were attacked by various predators, but parasitism by the platygastrid Platygaster robiniae Buhl & Duso was particularly significant. The impact of parasitism by P. robiniae is indicated as a key factor in reducing O. robiniae population densities.
Tachinid (Diptera: Tachinidae) Parasitoid Diversity and Temporal Abundance at a Single Site in the Northeastern United States
Authors: Inclan Diego J , Stireman John O 
Published: March 2011

AbstractAlthough tachinids are one of the most diverse families of Diptera and represent the largest group of nonhymenopteran parasitoids, their local diversity and distribution patterns of most species in the family are poorly known. In this study, 2 yr of samples from a Malaise trap were used to analyze the local richness and temporal distribution of a tachinid community in southwestern Ohio. In total, 883 tachinid specimens were collected, consisting of 117 species belonging to 69 genera. The majority of the specimens were collected in fall, followed by summer and spring, with 67, 22, and 11%, respectively. Estimated rarefaction curves indicate a predicted species richness of 217 species and suggest that we have sampled only a fraction of the diversity of Tachinidae occurring at this particular site. The species recorded in this study represent 16 and 19% of the species that are likely to occur in the northeastern United States and Ohio, respectively. In North America, there have been few, if any, previous attempts to quantify the diversity of tachinids on a local scale. Our results provide a baseline for understanding the temporal and spatial diversity of these ecologically and agronomically important parasitoids.
To Forage or Not: Responses of Bees to the Presence of Other Bees on Flowers
Authors: Yokoi Tomoyuki , Fujisaki Kenji 
Published: March 2011

AbstractInformation on responses of flower-foraging bees to the presence of other visitors simultaneously using the same resource is essential in further understanding bee decision-making processes during the collection of floral rewards. An individual must evaluate the relative costs of exploiting an occupied resource versus moving on to another resource. We investigated responses of foraging individuals to the presence of conspecifics or heterospecifics in three field experiments with solitary and social bees visiting flowers of wild strawberry, Rubus hirsutus Thunb. (Rosaceae). The proportion of Micrandrena spp. that occupied flowers after meeting other foragers was significantly lower than the proportions of Osmia orientalis Benoist and Apis mellifera L. Moreover, the avoidance response of Micrandrena spp. when approaching dead bees (“artificial” visitors) was stronger than that of the other bee species. We also placed an artificial visitor on flowers and observed subsequent responses of natural visitors. The responses of foraging bees to the presence of other visitors varies among species; O. orientalis more frequently visited flowers on which dead Micrandrena spp. were placed than flowers on which dead bees of other species were deployed. Both A. mellifera and Micrandrena spp. avoided flowers on which any other bees were set. We propose that O. orientalis makes decisions on whether to visit an occupied flower after discriminating between flower occupant species by body size.
Characterization of a New Odorant Binding Protein Gene in Gustatory Organs ofManduca sextaLarvae (Lepidoptera: Sphingidae)
Authors: Campo Marta L Del , Palmer Samantha , Caillaud Marina 
Published: March 2011

AbstractTaste plays an essential role in the identification of adequate food sources by insects, including lepidopterans. Characterizing genes that are important to successful transduction of tastants in insects leads to understanding of how tastants can regulate insect behavior. One class of proteins, odorant binding proteins (OBPs), have been shown to play a role in olfactory chemotransduction, but their role in taste transduction has been less clear, especially in immature stages of insects. Taste has been shown to be central in host preference by the larva of the tobacco hornworm, Manduca sexta (L.) (Lepidoptera: Sphingidae), and its preferred host plants in the family Solanaceae. We report the discovery of a new OBP gene, Mad10, expressed in the gustatory sensilla styloconica of M. sexta larvae. This is the first time that the expression of an OBP is found in the sensilla styloconica of any lepidopteran.
Distribution and Basic Biology of Black Cherry-Infesting Rhagoletis (Diptera: Tephritidae) in México
Authors: Rull Juan , Aluja Martin , Feder Jeffrey L 
Published: March 2011

Abstract
To better understand the phylogeography of Rhagoletis flies in the cingulata species group, we conducted a seven year host plant survey in México, behavioral observations, and studies on the basic biology of these tephritids. The survey revealed the existence of two geographically isolated Rhagoletis cingulata (Loew) populations in México. The first population was found to be restricted to Prunus serotina ssp. capuli (Cav.) McVaugh in an area within the central dry Altiplano spanning from Tlaxcala to México City and neighboring parts of the States of México, Puebla, and Hidalgo. The second population was found to infest Prunus serotina ssp. virens (Wooton & Standl.) McVaugh in high elevation areas of northeastern México between San Luis Potosí and Coahuila along the Sierra Madre Oriental. Both populations were hosts to the parasitoid Diachasmimorpha mellea (Gahan) (Hymenoptera: Braconidae), with percentage parasitism varying across sites. Collections of P. s. ssp. capuli and Prunus serotina Ehrh. ssp. serotina across the Eje Volcanico Trans Mexicano, the Sierra Madre del Sur, the Sierra de los Altos de Chiapas and mesic areas of the Sierra Madre Oriental between Veracruz and Queretaro failed to yield any pupae. Sites where pupae were recovered were significantly dryer than sites where R. cingulata was not found. Recovered flies were found to be univoltine and to overwinter as pupae. Adults in the field in Tlaxcala (Central Altiplano) were mainly sighted guarding, mating, and ovipositing in green fruit. Larval yield of fruit collected outside the natural area of distribution, and exposed to flies in the laboratory, was significantly lower than that of fruit collected within the natural range of R. cingulata. We compare distribution patterns with those of other species in the genus and discuss hypotheses to explain the outcome.
First Record of a Gynandromorph Orchid Bee,Euglossa iopoecila(Hymenoptera: Apidae: Euglossini)
Authors: Giangarelli D C , Sofia S H 
Published: March 2011

AbstractThis is a first description of a gynandromorph of an orchid bee, Euglossa iopoecila Dressier (Hymenoptera: Apidae: Euglossini). The specimen was collected at a chemical bait (eugenol) in an Atlantic Forest remnant in southern Brazil and shows a partial, bilateral asymmetry, with the right and left halves of the head displaying predominantly female and male characteristics, respectively. Except for the three left legs that show male morphology and a tuft of hairs detected only in the left side of second metasomal sternum (S2), the mesosoma and the metasoma exhibit female characteristics. The gynandromorph described here belongs to the mosaic or mixed category, because male and female characteristics are distributed patchily throughout the body of this individual. The main external morphological characteristics of the gynander are left and right antennae with 12 articles (like females), a mesosoma presenting a scutellar tuft (absent in males of this species), and a metasoma with six terga and six sterna that tapers to a point. Bilateral asymmetry in both metatibia is also noticeable: a normal corbicula is present in the right hind tibia, whereas the left hindleg brings a conspicuous deformation next to the tibial slit.
Two Cryptic Species in Brontispa longissima (Coleoptera: Chrysomelidae): Evidence from Mitochondrial DNA Analysis and Crosses between the Two Nominal Species
Authors: Takano Shun-Ichiro , Mochizuki Atsushi , Konishi Kazuhiko , Takasu Keiji , Alouw Jelfina C , Pandin Donata S , Nakamura Satoshi 
Published: March 2011

Abstract
The beetle Brontispa longissima (Gestro) (Coleoptera: Chrysomelidae) is a serious invasive pest of the coconut palm, Cocos nucifera I., in Southeast Asia and the Pacific region. Genetic analysis is essential to ecological and evolutionary study of such invasive species. We therefore conducted molecular analyses by using partial sequences (1044 bp) of the mitochondrial cytochrome oxidase subunit I (COI) genes of B. longissima collected from several locations. We found two monophyletic groups: one distributed over a limited area (Australia, Papua New Guinea, Samoa, and Sumba Island; referred to as the Pacific group) and the other collected from a wide area of Asia and the Pacific region (referred to as the Asian group). We compared the biological and morphological traits of the two groups. We found that insects in the Pacific group had a shorter developmental time from hatching to adult emergence, produced fewer eggs, and had a larger adult body size than insects in the Asian group. Elytral color patterns did not differ between the two groups. Our interpopulation crosses produced significantly fewer progeny than intrapopulation crosses, suggesting that B. longissima represents two cryptic species.
Analysis of Mitotic and Polytene Chromosomes and Photographic Polytene Chromosome Maps inBactrocera cucurbitae(Diptera: Tephritidae)
Authors: Zacharopoulou A , Sayed WAA , Augustinos A A , Yesmin F , Robinson A S , Franz G 
Published: March 2011

AbstractWe report here a cytogenetic analysis of the melon fly, Bactrocera Cucurbitae, Coquillett (Diptera: Tephritidae), a species of significant agricultural importance. The mitotic karyotype and detailed photographic maps of the larval salivary gland polytene chromosomes of the species are presented. The mitotic karyotype consists of six pairs of chromosomes including one pair of heteromorphic sex (XX/XY) chromosomes. The heterogametic sex is ascribed to the male. The analysis of polytene chromosomes has shown a total number of five long polytene elements (10 polytene arms) that correspond to the five autosomes. The characteristic features and the most prominent landmarks of each polytene chromosome are presented. The proposed chromosomal homology between B. Cucurbitae and Mediterranean fruit fly, Ceratitis capitata (Wiedemann), was determined by comparing chromosome banding patterns. The detection of heterozygous chromosome inversions in two strains is shown and discussed. The current study provides workable polytene chromosome maps of the species and compares our results with previous reports. We show that these maps can be used for cytogenetic studies in the species and for comparative studies among the tephritid species. They also can support the development of control methods and clarify the taxonomic status of B. cucurbitae.