bluuebunny/crossref_metadata_2025_split huggingface dataset:
Parabolic focusing pyrolytic graphite x-ray monochromator (abstract)a)
Authors: Dolbnya I. P. , Zolotarev K. V. , Sheromov M. A. , Antonov A. A. , Grigoryeva I. G. 
Published: July 2002

The results of the experimental testing of the parabolic focusing pyrolytic graphite x-ray monochromator (mono) on the wiggler (2 T) synchrotron radiation (SR) beamline of the VEPP-3 storage ring are presented. The monochromatization and the focusing of x radiation in both vertical and horizontal directions are provided by the optical properties of the parabolic surface of revolution of the properly shaped pyrolytic graphite crystal attached to the parabolic-machined brass support. A single crystal is a half of the parabolic surface 160 mm long and ∼19 mm minimal focus length. The sagittal radii are changed from 10 to 30 mm. The available photon energy range is 7–20 keV on the first harmonic of reflection. The second order of reflection still has a reasonably high intensity comparable with the intensity of the first one; due to this fact the energy range can be extended up to 40 keV. The change of the energy of the monochromatized x radiation is accomplished by the simple vertical shift of a mono; according to this shift the space location of the focal point is also vertically displaced. For the study the mono was placed at a distance of ∼16 m from the source point, so the accepted horizontal divergence of the ‘‘white’’ SR beam was ∼2 mrad. The mono was supplied with an In–Sn conical collimator to prevent parasitic scattering radiation and to avoid the possible undesirable characteristic emission x-ray lines in the working energy range mentioned above.
X-ray imaging of different cross sections (horizontal–vertical, horizontal–longitudinal, vertical–longitudinal) of the focal point space region was performed by the point-by-point scanning of a NaI(Tl) scintillation counter supplied by the pinhole collimator of ∼80 μm in diameter made in the lead disk screen of 2 mm thickness. The achieved size of the focal spot of ∼0.4 (horizontal)×0.7(vertical) mm2 is in a good agreement with theoretical expectations and preliminary computer modeling. In fact, the main role in an extending of the focal spot is the large angular mosaic spread (∼1° FWHM) of the graphite crystal used. The registration of Compton scattered radiation spectra from the acrylic cylinder of 5 mm diameter placed at the focus position by a Si(Li) liquid–nitrogen-cooled solid state detector was conducted to measure the behavior of spectra of monochromatic x radiation output with respect to the longitudinal location of the footprint of a primary SR beam on the parabolic surface of the graphite crystal. The possible applications of the presented mono for the construction of a ‘‘middle’’ space resolution class of SR based x-ray fluorescence microprobes and other usages such as powerful concentrators of x radiation are discussed and described.
Low-frequency Raman investigation of lead-containing fluorozirconate glasses and melts
Authors: Walrafen G. E. , Hokmabadi M. S. , Guha S. , Krishnan P. N. , Tran D. C. 
Published: July 2002

Raman measurements of fluorozirconate glasses and melts were conducted from −265 (8.5 K) to ∼800 °C for numerous compositions, e.g., from 30 mol % BaF2 (no PbF2) to 35 mol % PbF2 (no BaF2), at nearly constant ZrF4 content. The normalized amplitude of the nominal 45 cm−1 peak was found to increase linearly with increasing PbF2 from 0–35 mol %, as the peak frequency decreased slightly, from ∼47 to ∼43 cm−1.
From these observations, depolarization ratios, Pb–F force constants, etc., it was concluded that the 45 cm−1 peak involves a correlated motion of second-neighbor Pb2++Zr4+ or Ba2++Zr4+ cations vibrating against their edge- (or corner-) shared coordination cages of F− anions. Martin–Brenig-type analysis of the band shape below ∼50 cm−1 (at −265 °C) yielded a structural correlation length, SCL=2σ=6.2±0.2 Å (0–15 mol % PbF2). This SCL corresponds to a repeat distance, e.g., the Ba–Zr separation of the Ba(F2)Zr edge-sharing, 4.1–4.2 Å, plus the Zr–F bond length, 2.1 Å, of the ZrF4−nn polyhedra, 5&lt;n&lt;7, and n=CN. Normalized Bose–Einstein corrected difference spectra, I35%–I0% (mol % PbF2), and for 5 mol % PbF2, I635–I25 (°C), show common frequencies between ∼200–500 cm−1 which refer mainly to edge or corner sharing between the ZrF4−nn , PbF2−ll , and BaF2−mm polyhedra, l, m=CN. The 45 cm−1 peak frequency decreases sigmoidally with temperature rise, dropping steeply near TG, and reaching a ∼5 cm−1 limit in the melt. This and the rough density modulation observed for the mode frequency are indicative of viscoelasticity. The virtual absence of the low-frequency mode in the melt due to the Pb+Zr and Ba+Zr vs F cage motions occurs simultaneously with the disappearance of the F sharing modes. For a total stoichiometric F/Zr mole ratio of 5.5 for the melt, nearly free ZrF−5 , ZrF2−6 , and ZrF3−7 anions are indicated.
Aerodynamic focusing of heavy molecules in seeded supersonic jets
Authors: Fernandez de la Mora J. , Rosell-Llompart J. 
Published: July 2002

The phenomenon of aerodynamic enrichment of heavy molecules seeded in supersonic free jets has been known since 1955. But its systematic exploitation in the generation of intensely focused molecular beams has been prevented by the lack of a quantitative and realistic explanation of the observed facts. Here, the aerodynamic focusing of CBr4, W(CO)6, and C2Cl6 molecules seeded in jets of He or H2 is studied experimentally, and found to be most singular under conditions similar to those known to produce sharply focused beams of microscopic spheres suspended in air jets. The gas mixture expands through thin-plate orifice into a vacuum chamber, forming a supersonic free jet. The spacial distribution of the heavy molecules in the jet is measured at varying distances L to the nozzle by scanning a thermocouple probe across a jet diameter. The probe is sufficiently small to interfere negligibly with the flow. The increment DV in the thermocouple voltage resulting from seeding the heavy gas on a given flow of He or H2 is seen to be a sensitive indicator of the local concentration of seed molecules in the jet. The following behavior is observed in terms of the same Stokes number or inertia parameter S that governs the simpler and better understood phenomenon of aerosol focusing. Below S=0.4 for H2 and S=0.2 for He, heavy molecule and aerosol beam widths are practically identical, and the boundary of the jet of heavy molecules is rather sharp. At higher values of S, aerosol beams show further reductions
in cross section, down to less than 10% of a nozzle throat diameter dn. In contrast, the measured heavy species minimal beam widths or waists at a distance L∼dn from the throat are around 0.5
d n and 0.35 dn for jets of He and H2, respectively. In units of dn, these widths are several times larger than expected from elementary considerations on the defocusing effects due to Brownian motion (of the order of the square root of the molecular mass ratio between light and heavy molecules). Nonetheless, the thin-plate orifice nozzle yields considerably more concentrated jets of heavy gases than previously seen, with far-field enrichment factors for the seed species close to 50 in the
case of H2 jets. This technique, thus, appears to provide a greatly
improved source for intense molecular beams. Aerodynamically focused beams have a sharp distribution of kinetic energies, being ideally suited for cross beam and beam surface studies. But they are not quite so optimal for spectroscopic studies because they require moderate source Reynolds numbers (of order 100), at which the heavy gas undergoes very little translational, rotational, or vibrational cooling.
The Newton variational functional for the log-derivative matrix: Use of the reference energy Green’s function in an exchange problem
Authors: Ramachandran B. , D’Mello Michael , Wyatt Robert E. 
Published: July 2002

The Newton Variational Principle for the log-derivative matrix (the Y-NVP) is studied in the context of a collinear exchange problem. In contrast to the integral equation methods that calculate the K or the T matrices directly, the matrix elements of the log-derivative Newton functional can be made independent of the scattering energy. This promises considerable savings in computational effort when state to state transition probabilities are calculated at several energies, since the matrix elements of the functional need be calculated only once. Green’s functions defined with respect to a reference energy, called the reference energy Green’s functions (or the REGFs), play a central role in the Y-NVP functional. The REGFs may be defined with or without reference to asymptotic channel energies. If channel dependent REGFs are used, the Y-NVP converges at the same rate as the GNVP for the K or T matrices, when the scattering energy is the same as the reference energy. On the other hand, channel independent REGFs permit even further reductions in computational effort.
We use both types of REGFs in the present paper, and compare the rates of convergence. These comparisons show that the convergence rate of the method is not significantly altered by the type of REGF used. Further, we show that the Y-NVP is able to achieve rapid convergence of reactive transition probabilities over a large range of scattering energies, even when scattering resonances are present. An analysis of the computational effort required for each part of the calculation leads to the conclusion that a Y-NVP calculation using a channel independent REGF requires essentially only the same amount of computer time as a log-derivative Kohn (Y-KVP) calculation, while, presumably, offering faster convergence.
Triple-resonance spectroscopy of the higher excited states of NO2. IV. Trends in the mode dependence of vibrational autoionization via asymmetric stretch versus symmetric stretch and bend
Authors: Bryant Gregg P. , Jiang Yanan , Grant Edward R. 
Published: July 2002

Multiresonant stepwise excitation of NO2 isolates series of individual rovibronic states converging to vibrationally excited levels of NO+2. Resonances detected by third-photon photoionization of two-photon photoselected intermediate states show characteristic patterns of intensity and linewidth that convey information on the dynamics of vibrational autoionization for relaxation in specific normal modes of the linear NO+2 core. Earlier studies characterized vibrational-to-Rydberg-electronic energy transfer from symmetric stretching (100) and bending (010) excited states [J. Chem. Phys. 93, 2308, 7731 (1990)]. In the present work, a definitive assignment of double-resonant rotational structure confirms two-color selection of 3pσ 2∑+u gateway states that are core excited by one quantum of asymmetric stretch. Ionization-detected optical-absorption scans from the double-resonantly selected N′=2 level of the 3pσ (001) state yield spectra of s, d, and g Rydberg series of vibrationally autoionizing resonances converging to the (001) ionization threshold. Transitions assigned to s and d series range in principal quantum number from 7 to more than 30. As with the spectrum of states built on the (100) core, transitions assigned to g states form a series of sharp resonances that disappears at relatively low n.
Regions of the (001) autoionizing spectrum are perturbed by discrete–discrete interactions with underlying series converging to lower thresholds, and comparatively low intensities are found for whole series of states with higher Rydberg orbital angular momentum. Nevertheless, resonant linewidths for (001) can be compared with (100) and (010) for the most penetrating series (ns), and a clear trend manifests itself over complete autoionizing intervals for all three vibrational states of the core. Symmetric stretching states, with the largest dynamic volume change over a cycle of vibration, autoionize fastest. Asymmetric stretch, with a smaller volume change, but comparable N–O bond displacements, is coupled less strongly. Bending, which supports a large dynamic dipole, but little change in the volume of the core charge distribution, displays the slowest relaxation to the NO+2 (000) continuum. These trends in vibrational state dependence are in qualitative accord with a simple long-range picture that relates the strength of Rydberg-continuum coupling, induced by vibrational motion in the core, to the size of the associated dynamic monopole.
Voice problems in female‐to‐male transsexuals
Authors: van Borsel J. , de Cuypere G. , Rubens R. , Destaerke B. 
Published: July 2002

AbstractVoice therapy with the aim of raising a client's fundamental frequency is a common practice in the reassignment of male‐to‐female transsexuals. In female‐to‐male transsexuals on the other hand voice therapy is usually not considered since the administration of androgens is assumed automatically to change the voice in the direction of the desired sex. The present study examined whether the voice change in female‐to‐male transsexuals is indeed as straightforward as it is assumed. Results from a sample survey involving 16 female‐to‐male transsexuals and longitudinal data from two clients suggest that the voice change in female‐to‐male transsexuals is not always totally unproblematic. A voice assessment and some counselling before the hormone therapy are recommended.
Interaction between children with cerebral palsy and their mothers: the effects of speech intelligibility
Authors: Pennington Lindsay , McConachie Helen 
Published: July 2002

AbstractChildren with cerebral palsy and severe speech disorders have been described as passive communicators, whose conversation partners control and dominate interaction. This paper studies the effects of speech intelligibility on interaction between mothers and their children with cerebral palsy to examine if similar patterns of child passivity and adult domination are also observed in dyads in which children are physically dependent but naturally intelligible to their parents. Two groups, each of 20 children who had four‐limb cerebral palsy and who differed in their speech intelligibility, participated in the study. Children in Group 1 (whose interaction has been previously reported) were unintelligible to their parents out of context. Children in Group 2 had speech that was understood without situational cues. Children and their mothers were videotaped playing with a set of toys that had been shown to elicit from non‐disabled children a full range of the conversational moves and speech acts targeted in the study. Videotaped interaction was transcribed and coded at three levels to show conversation structure, the pragmatic functions expressed and the method of communication used. Percentage distribution of coding categories was compared across groups using coda. Results showed that verbally intelligible children initiated more conversations and used their communication for a wider range of functions than did non‐speaking children, for whom more restricted patterns of conversation were noted. Unexpectedly, few differences were observed between the two groups of mothers, who initiated and closed most exchanges. Implications for intervention are discussed.
The Tetraspan Molecule Cd151, a Novel Constituent of Hemidesmosomes, Associates with the Integrin α6β4 and May Regulate the Spatial Organization of Hemidesmosomes
Authors: Sterk Lotus M.Th. , Geuijen Cecile A.W. , Oomen Lauran C.J.M. , Calafat Jero , Janssen Hans , Sonnenberg Arnoud 
Published: July 2002

CD151 is a cell surface protein that belongs to the tetraspan superfamily. It associates with other tetraspan molecules and certain integrins to form large complexes at the cell surface. CD151 is expressed by a variety of epithelia and mesenchymal cells. We demonstrate here that in human skin CD151 is codistributed with α3β1 and α6β4 at the basolateral surface of basal keratinocytes. Immunoelectron microscopy showed that CD151 is concentrated in hemidesmosomes. By immunoprecipitation from transfected K562 cells, we established that CD151 associates with α3β1 and α6β4. In β4-deficient pyloric atresia associated with junctional epidermolysis bullosa (PA-JEB) keratinocytes, CD151 and α3β1 are clustered together at the basal cell surface in association with patches of laminin-5. Focal adhesions are present at the periphery of these clusters, connected with actin filaments, and they contain both CD151 and α3β1. Transient transfection studies of PA-JEB cells with β4 revealed that the integrin α6β4 becomes incorporated into the α3β1-CD151 clusters where it induces the formation of hemidesmosomes. As a result, the amount of α3β1 in the clusters diminishes and the protein becomes restricted to the peripheral focal adhesions. Furthermore, CD151 becomes predominantly associated with α6β4 in hemidesmosomes, whereas its codistribution with α3β1 in focal adhesions becomes partial. The localization of α6β4 in the pre-hemidesmosomal clusters is accompanied by a strong upregulation of CD151, which is at least partly due to increased cell surface expression. Using β4 chimeras containing the extracellular and transmembrane domain of the IL-2 receptor and the cytoplasmic domain of β4, we found that for recruitment of CD151 into hemidesmosomes, the β4 subunit must be associated with α6, confirming that integrins associate with tetraspans via their α subunits. CD151 is the only tetraspan identified in hemidesmosomal structures. Others, such as CD9 and CD81, remain diffusely distributed at the cell surface.
In conclusion, we show that CD151 is a major component of (pre)-hemidesmosomal structures and that its recruitment into hemidesmosomes is regulated by the integrin α6β4. We suggest that CD151 plays a role in the formation and stability of hemidesmosomes by providing a framework for the spatial organization of the different hemidesmosomal components.
Oxygen Vacancy‐Mediated Growth of Amorphous Discharge Products toward an Ultrawide Band Light‐Assisted Li–O2 Batteries
Authors: Li Fei , Li Ma‐Lin , Wang Huan‐Feng , Wang Xiao‐Xue , Zheng Li‐Jun , Guan De‐Hui , Chang Li‐Min , Xu Ji‐Jing , Wang Yu 
Published: February 2022

AbstractPhotoassisted electrochemical reaction is regarded as an effective approach to reduce the overpotential of lithium–oxygen (Li–O2) batteries. However, the achievement of both broadband absorption and long term battery cycling stability are still a formidable challenge. Herein, an oxygen vacancy‐mediated fast kinetics for a photoassisted Li–O2 system is developed with a silver/bismuth molybdate (Ag/Bi2MoO6) hybrid cathode. The cathode can offer both double advantages for light absorption covering UV to visible region and excellent electrochemical activity for O2. Upon discharging, the photoexcited electrons from Ag nanoplate based on the localized surface plasmon resonance (LSPR) are injected into the oxygen vacancy in Bi2MoO6. The fast oxygen reaction kinetics generate the amorphous Li2O2, and the discharge plateau is improved to 3.05 V. Upon charging, the photoexcited holes are capable to decompose amorphous Li2O2 promptly, yielding a very low charge plateau of 3.25 V. A first cycle round‐trip efficiency is 93.8% and retention of 70% over 500 h, which is the longest cycle life ever reported in photoassisted Li–O2 batteries. This work offers a general and reliable strategy for boosting the electrochemical kinetics by tailoring the crystalline of Li2O2 with wide‐band light.
Electrically Programmable Interfacial Adhesion for Ultrastrong Hydrogel Bonding
Authors: Liu Yaqian , Wang Pudi , Su Xing , Xu Liang , Tian Zhuoling , Wang Hao , Ji Guojun , Huang Jianyong 
Published: February 2022

AbstractAdjustable interfacial adhesion is of great significance in smart‐hydrogel‐related engineering fields. This study presents an electroadhesion strategy for universal and ultrastrong hydrogel bonding with electrically programmable strength. An ionic hydrogel containing lithium ions is designed to achieve hydrated‐ion‐diffusion‐mediated interfacial adhesion, where external electric fields are employed to precisely control spatiotemporal dynamics of the ion diffusion across ionic adhesion region (IAR). The hydrogel can realize a universal, ultrastrong, efficient, tough, reversible, and environmentally tolerant electroadhesion to diverse hydrogels, whose peak adhesion strength and interfacial adhesion toughness are as high as 1.2 MPa and 3750 J m−2, respectively. With a mechanoelectric coupling model, the dominant role of the hydrated ions in IAR played in the interfacial electroadhesion is further quantitatively revealed. The proposed strategy opens a door for developing high‐performance adhesion hydrogels with electrically programmable functions, which are indispensable for various emerging fields like flexible electronics and soft robotics.
2D FeOCl: A Highly In‐Plane Anisotropic Antiferromagnetic Semiconductor Synthesized via Temperature‐Oscillation Chemical Vapor Transport
Authors: Zeng Yi , Gu Pingfan , Zhao Zijing , Zhang Biao , Lin Zhongchong , Peng Yuxuan , Li Wei , Zhao Wanting , Leng Yuchen , Tan Pingheng , Yang Teng , Zhang Zhidong , Song Youting , Yang Jinbo , Ye Yu , Tian Kesong , Hou Yanglong 
Published: February 2022

Abstract2D van der Waals (vdW) transition‐metal oxyhalides with low symmetry, novel magnetism, and good stability provide a versatile platform for conducting fundamental research and developing spintronics. Antiferromagnetic FeOCl has attracted significant interest owing to its unique semiconductor properties and relatively high Néel temperature. Herein, good‐quality centimeter‐scale FeOCl single crystals are controllably synthesized using the universal temperature‐oscillation chemical vapor transport (TO‐CVT) method. The crystal structure, bandgap, and anisotropic behavior of the 2D FeOCl are explored in detail. The absorption spectrum and electrical measurements reveal that 2D FeOCl is a semiconductor with an optical bandgap of ≈2.1 eV and a resistivity of ≈10−1 Ω m at 295 K, and the bandgap increases with decreasing thickness. Strong in‐plane optical and electrical anisotropies are observed in 2D FeOCl flakes, and the maximum resistance anisotropic ratio reaches 2.66 at 295 K. Additionally, the lattice vibration modes are studied through temperature‐dependent Raman spectra and first‐principles density functional calculations. A significant decrease in the Raman frequencies below the Néel temperature is observed, which results from the strong spin−phonon coupling effect in 2D FeOCl. This study provides a high‐quality low‐symmetry vdW magnetic candidate for miniaturized spintronics.
The problem with open geospatial data for on‐farm research
Authors: Prince Czarnecki Joby M. , Jones Mary Ann 
Published: February 2022

AbstractScientists are under increased pressure to provide research data freely and openly to all interested parties as a means of furthering science. More than sharing data, there is an additional expectation that data comply to Findable, Accessible, Interoperable, Reusable (FAIR) principles. The requirement to share data presents challenges for farm geospatial data. The primary contention of this commentary is that data sharing requirements will make on‐farm research increasingly difficult while also not achieving the stated purposes of opening data. De‐identification of farm geospatial data is not sufficient to protect privacy, reducing likelihood of participation in research. Moreover, de‐identified farm geospatial data will have greatly reduced reusability. Limited guidance is available on appropriate mechanisms for sharing of farm geospatial data. This commentary briefly summarizes benefits and realities of data sharing, expands discussion to support the primary contention, and concludes with high‐level suggestions for moving forward.