UK PubMed Central (United Kingdom)

OBJECTIVES: To define a method for measurement of the cross sectional area and volume of the quadriceps femoris muscle using magnetic resonance imaging (MRI) in conjunction with stereology, and to compare...Full Text Available

KoreaScience (Korea)

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UK PubMed Central (United Kingdom)

To determine the reliability of concentric quadriceps muscle torque at 30°, 60°, and 75° of knee extension, 25 female university students were studied. Each subject was tested...Full Text Available

UK PubMed Central (United Kingdom)

AbstractWe combined atomistic molecular-dynamics simulations with quantum-mechanical calculations to investigate the sequence dependence of the stretching behavior of duplex DNA. Our...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

For sufficiently cool remote gases, the cylindrical stretched flame shows classical ignition-extinction behavior. For remote gas temperatures close to the adiabatic flame temperature, the flame response is qualitatively different, with negative flame speed solutions which may be physically accessible.

Energy Technology Data Exchange (ETDEWEB)

Purpose: {sup 31}P-MRS is used to assess the influence of sex and age on quadriceps muscle metabolism before and after exercise. Materials and Methods: 32 healthy volunteers (15 women, 17 men; mean age: 38{+-}17 yrs.) were examined by dynamic phosphorus-31 ({sup 31}P) magnetic resonance spectroscopy (MRS). In the magnet, the quadriceps muscle was stressed by an isometric and an isotonic form of exercise until exhaustion, respectively. Results: Resting conditions: With increasing subjects` age, the ratio {beta}-adenosine triphosphate/total phosphate decreased (r=-0.37; p=0.02). With increasing subjects` age, the ratios inorganic phosphate/phosphocreatine (r=0.79; p=5x10{sup -8}), phosphomonoester/{beta}-adenosine triphosphate (r=0.74; p=10{sup -6}) and phosphodiester/{beta}-adenosine triphosphate (r=0.62; p=10{sup -4}) increased. The pH was the only one of the evaluated spectroscopic parameters which showed a sex-dependence: Female subjects had ...

UK PubMed Central (United Kingdom)

BackgroundDuplications of stretches of the genome are an important source of individual genetic variation, but their unrecognized presence in laboratory organisms would be a confounding...Full Text Available

International Nuclear Information System (INIS)

Stretch-out operation mode can deepen the reactor burnup when the boron concentration is near 0 mg/L, in which the additional reactivity is introduced by the reducing of the moderator temperature and the decreasing of the load. Stretch-out is used in many nuclear power plants all over the world. The first stretch-out operation has been used for the first time in China. As a specific operation mode, which outruns the original reactor core design, the related and specialized design argument and safety analysis is required. As a consequence of the continuous or stepwise reduction of load and moderator temperature, the neurotic measurement system and the reactor control and protection system parameters should be modified specially. Based on the schedule of the electricity production, the first stretch-out operation had been carried out from March 12 to March 21 2003. It successfully avoided the overlapping ...

UK PubMed Central (United Kingdom)

Catch is a mechanical state occurring in some invertebrate smooth muscles characterized by high force maintenance and resistance to stretch during extremely slow relaxation. During catch, intracellular...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundAdhesive Capsulitis (AC) affects patient of all ages, and stretching protocols are commonly prescribed for this condition. Dynamic splinting has been shown effective in...Full Text Available

International Nuclear Information System (INIS)

We review two types of D-brane processes where open strings are created. In the first type, a closed string incident on a collection of D-branes is converted into a number of open strings running along them. For the case of threebranes we compare the leading absorption rate with that in semiclassical gravity, and find exact agreement. A supersymmetric non-renormalization theorem guarantees that this agreement survives all corrections in powers of the string coupling times the number of branes. The second type of process is creation of stretched open strings by crossing D-branes. We show that this is possible whenever a p-brane passes through an (8-p)-brane positioned orthogonally to it. The extra attractive force exerted by the stretched open string is crucial for finding that the net force cancels in this BPS system. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Measurements of the relaxation of the D{sub 2}O stretch mode in vitreous As{sub 2}S{sub 3} are presented. Because the bending mode of the molecule offers an intra-molecular decay channel for the stretch mode, the decay scheme of the D{sub 2}O molecule is more complex than that of diatomic molecules. The asymmetric stretch mode of D{sub 2}O has a frequency of 2680 cm{sup -1}. To study the relaxation of this mode we applied a pump-probe technique, using intense psec; pulses of the Stanford Free Electron Laser. Due to the small cross-section of the vibrational mode, successful efforts were made to improve the signal to noise ratio by using a laser stabilization system and a tightly focused beam to increase the intensity, by averaging the signal with a kHz repetition rate and by using samples with an optimized D{sub 2}O concentration. A rapid relaxation rate on the order of 5 x 10{sup 9} sec{sup -1} at low temperature is found ...

International Nuclear Information System (INIS)

The governor model is extended to include the asymmetric shape of nuclei which allows a simultaneous analysis of the data for both the ground state and the #gamma#-vibrational bands in deformed even-even nuclei. The rotationally invariant core is assumed to be a spheroid with an axis of symmetry parallel to the axis of rotation. The calculations are carried out under the assumption of no stretching. The static #gamma#-deformation results are compared with the VMI(ARM) and Krutov values, and the calculated energies are in good agreement with the experimental data.

Energy Technology Data Exchange (ETDEWEB)

The suitability of the turbulent combustion flamelets model in order to predict the index of NO{sub x} production in turbulent flames of hydrogen diffusion is analyzed. In the flamelet approach, the turbulent flame is equivalent to a group of laminar flames submitted to a mechanical stretching which generates a chemical disequilibrium. This effect can be described by the stretching or by the scalar dissipation ratio. A numerical modeling is performed in order to evaluate the advantages of both approaches and to compare the behaviour of the NO{sub x} emission index with the experiments of Chen and Driscoll. This study shows that predictions of NO{sub x} emission indexes have a correct behaviour with respect to the Damkoehler number only when the scalar dissipation ratio is used as a parameter to describe the chemical state outside equilibrium. Predictions of the flamelet models are improving when the Damkoehler number increases. On the other ...

Energy Technology Data Exchange (ETDEWEB)

This paper reports progress in the fabrication and characterization of an array of 1nm-scale colloidal particles (i.e., quantum-dot array) that can be operated to execute nontrivial and innovative computations, possibly including quantum logic. We discuss the actual fabrication of 2-nm metal clusters as an example of possible quantum dot implementation. Innovative and unconventional paradigms underlie the different stages of this work. For example, regular array geometry is achieved by directing appropriately derivatized metal clusters to preselected locations along a stretched strand of an engineered DNA sequence.

CERN Document Server

We study suspensions of semi-flexible colloidal rods and biopolymers using an Onsager-type second-virial functional for a segmented-chain model. For suspensions of thin and thick fd virus particles we calculate phase diagrams in quantitative agreement with experimental observations, and we find their effective state-point dependent shape to be much shorter and thicker than the actual shape. We also calculate the stretching of worm-like micelles in a host fd virus solution, again finding agreement with experiments. For both systems, our results show that the fd virus stiffness can play a key role in system behavior.

International Nuclear Information System (INIS)

Coherent x-ray production by a seeded free electron laser (FEL) is important for next generation synchrotron light sources. The authors examine the feasibility and features of FEL emission seeded by a high-order harmonic generation (HHG) of an infrared laser. In addition to the intrinsic FEL chirp, the longitudinal profile and spectral bandwidth of the HHG seed are modified significantly by the FEL interaction well before saturation. This smears out the original attosecond pulselet structure. The authors introduce criteria for this smearing effect on the pulselet and the stretching effect on the entire pulse. They discuss the noise issue in such a seeded FEL.

International Nuclear Information System (INIS)

A new potential function based on spectroscopic results for diatomic molecules is presented and applied to the hydrogen bonding systems. The potential energy of interaction is supposed to have electrostatic, polarization, dispersion, repulsion and effective charge-transfer contributions. Estimates of the effective charge-transfer quantity have been made based on the average charge of the proton donor and the acceptor atoms. For dimers such as water, methanol, acetic acid and formic acid, the vibrational stretching frequencies and dimerization energies are calculated and discussed in connection with Badger-Bauer rule. (author).

Science.gov (United States)

The utility of recording Raman spectroscopy under liquid nitrogen, a technique we call Raman Under Nitrogen (RUN), is demonstrated for ferrocene, uranocene and thorocene. Using RUN, low temperature (liquid nitrogen cooled) Raman spectra for these compounds exhibit higher resolution than previous studies and new vibrational features are reported. The first Raman spectra of crystalline uranocene at 77 K are reported using excitation from argon (5145 ) and krypton (6764 ) ion lasers. The spectra obtained showed bands corresponding to vibrational transitions at 212, 236, 259, 379, 753, 897, 1500, and 3042 cm-1 , assigned to ring-metal-ring stretching, ring-metal tilting, out-of-plane CCC bending, in-plane CCC bending, ring-breathing, C-H bending, CC stretching and CH stretching, respectively. The assigned vibrational bands are compared to those of uranocene in THF and thorocene. All vibrational frequencies of the ligands, ...

British Library Electronic Table of Contents (United Kingdom)

We have carried out transverse-field ( Formula Not Shown ) Formula Not Shown SR experiments in Formula Not Shown for temperatures from 300 down to 2.2K. The muon-decay asymmetry can be fit to a stretched exponential relaxation function: Formula Not Shown . The exponent Formula Not Shown for Formula Not Shown , but drops continuously below this temperature (being Formula Not Shown for Formula Not Shown and reaching Formula Not Shown near 2K). The characteristic relaxation rate Formula Not Shown grows six-fold in the experimental temperature range (from Formula Not Shown for Formula Not Shown to Formula Not Shown for Formula Not Shown ). Independently of theoretical models, the behavior of these parameters is consistent with strong magnetic disorder. Although the magnetic susceptibility of F...

British Library Electronic Table of Contents (United Kingdom)

We present modeling, simulation, and characterization for the dynamic response of clamped-clamped microbeams under mechanical shock. A Galerkin-based reduced-order model is utilized and its results are verified by comparing to finite-element results. The results indicate that the response of a microbeam to mechanical shock is inherently non-linear because of the dominating effect of mid-plane stretching. The effect of the shock pulse shape is investigated. It is concluded that the shape of the shock pulse can result in significant dynamic amplification in the response of the microbeam even in cases where the shock load is considered quasi-static.The combined effect of the electrostatic force and mechanical shock is investigated. The results show that this combined effect can lead to early ...

CERN Document Server

We study analytically and numerically the stability of the pressure-less, viscously spreading accretion ring. We show that the ring is unstable to small non-axisymmetric perturbations. To perform the perturbation analysis of the ring we use a stretching transformation of the time coordinate. We find that to 1st order, one-armed spiral structures, and to 2nd order additionally two-armed spiral features may appear. Furthermore, we identify a dispersion relation determining the instability of the ring. The theoretical results are confirmed in several simulations, using two different numerical methods. These computations prove independently the existence of a secular spiral instability driven by viscosity, which evolves into persisting leading and trailing spiral waves. Our results settle the question whether the spiral structures found in earlier simulations of the spreading ring are numerical artifacts or genuine instabilities.

International Nuclear Information System (INIS)

Oxovanadium(IV) complexes with tridentate dibasic ONO donor schiff bases derived from salicylaldehyde, 5-chlorosalicylaldehyde, 3,5-dichlorosalicylaldehyde, 5-bromosalicylaldehyde, 3-methoxysalicylaldehyde, 2-hydroxynaphthaldehyde and 2-amino-1-propanol have been prepared and characterised by elemental analysis, infrared, electronic and ESR spectra and magnetic susceptibility measurements from 83 to 297 deg K. On the basis of these studies, presence of triplet state (S=1) and a dimeric structure with singlet ground state (S=0) have been suggested. The V=0 stretching frequencies of the complexes occur around 980 cm"-"1. (M.G.B.).

Energy Technology Data Exchange (ETDEWEB)

The pronounced selectivity of near-threshold (p,..pi../sup -/) reactions for high-spin two-particle, one-hole states is exploited, in the first spectroscopic application of a (p,..pi..) reaction, to identify previously unknown 25/2/sup +/ and 21/2/sup +/ (g/sub 9/2/)/sup 3/ states in /sup 89/Zr. Relative cross sections for the two transitions are well reproduced by simple model calculations. The analyzing power for the 25/2/sup +/ state is markedly similar to previous (p/sub pol/,..pi../sup -/) results for two-particle one-hole stretched states in lighter nuclei.

Energy Technology Data Exchange (ETDEWEB)

A numerical model for the development of bed dominated scour around sub-sea structures is presented. The hydrodynamic part of the model is based on a modified potential flow theory. The purpose of the present study has been to develop relatively simple models, yet complex enough to capture the main physics that can be used as engineering tools. An overview of scour phenomena and the basic problems of scour in steady current flow is presented. A hydrodynamic model for horseshoe vortex is presented, as well as a model for the bed transport, and examples are given. The scour in oscillatory flow and a curvilinear model for suspended sediment calculations are described. An advection-diffusion model (formulated in a curvilinear stretched coordinate system) has been developed and is described in an article which has been submitted for publication, a copy of the article is enclosed in Appendix E of the report. (EG)

British Library Electronic Table of Contents (United Kingdom)

Many aspects of cellular motility and mechanics are cyclic in nature such as the extension and retraction of lamellipodia or filopodia. Inherent to the cycles of extension and retraction that test the environment is the production of mechano-chemical signals that can alter long-term cell behavior, transcription patterns, and cell fate. We are just starting to define such cycles in several aspects of cell motility, including periodic contractions, integrin cycles of binding and release as well as the normal oscillations in motile activity. Cycles of local cell contraction and release are directly coupled to cycles of stressing and releasing extracellular contacts (matrix or cells) as well as cytoplasmic mechanotransducers. Stretching can alter external physical properties or sites exposed b...

Energy Technology Data Exchange (ETDEWEB)

Amphiphysin is a protein concentrated in neuronal synapses and peripherally associated with neurotransmitter vesicles. It is expressed in many neurons of the central and peripheral nervous systems, in the adrenal medulla, in the anterior and posterior pituitary, in cell lines of the endocrine pancreas, and in spermatocytes. Its subcellular localization and tissue distribution indicate a potential involvement in mechanisms of regulated exocytosis. A role in the dynamic organization of the membrane-associated cytoskeleton is suggested by structural homology to the products of two yeast genes, RVS161 and RVS167, whose mutation results in an abnormal actin distribution, disturbs budding morphology, and impairs cell entry into stationary phase. Limited stretches of sequence similarity, including an SH3 domain, are also shared with other actin-binding proteins. Amphiphysin is the dominant autoantigen in paraneoplastic Stiff-Man syndrome, a neurological autoimmune ...

Energy Technology Data Exchange (ETDEWEB)

During a Workshop on Gamma-Gamma Colliders in Lawrence Berkeley Laboratory, it was pointed out that an 1-{mu}m laser that can produce 1-J, 1-ps pulses at a few hundred hertz is required. With high-power scalability and ease of formatting, an FEL can be a promising candidate for such a laser. The authors propose an FEL scheme based on chirped-pulsed regenerative amplification to achieve this high peak-power laser. The 1-ps pulse of a solid-state laser will be stretched, amplified, and recompressed to achieve the high peak power. The system is relatively simple and consists of mostly components that have already been demonstrated. This paper will describe the proposal and the important issues of such a scheme.

Energy Technology Data Exchange (ETDEWEB)

The temperature dependent vibrational relaxation of the CO stretching mode of Rhodium dicarbonyl acetylacetonate (Rh(CO){sub 2}(acac)) and tungsten hexacarbonyl (W(CO){sub 6}) in dibutylphthalate (DBP) and 2-methylpentane (2-MP) were measured with IR pump and probe (P-P) experiments. The experiments were performed with {approximately}1.5 ps pulses generated by the Stanford superconducting accelerator pumped free electron laser (FEL). Measurements were performed on the Rh(CO){sub 2}(acac) CO asymmetric stretching mode at {lambda} = 4.98{mu}m from 10 K to 300 K. Both the parallel and magic angle probe polarizations decay curves are biexponential over the entire temperature range. The slow component (ranging from 40 ps at 300 K to 55 ps at 10K) is attributed to the population relaxations. For the fast component (ranging from 4-5 ps at 300 K to 13-15 ps at 10K), we propose a mechanism of spectral diffusion, in contrast to the previously proposed ...

Energy Technology Data Exchange (ETDEWEB)

The IR spectra of complexes of uranyl perhalates with antipyrine (AP), hexamethylphosphorus triamide (HMPTA), dimethyl sulfoxide (DMSO), and water with the composition (UO/sub 2/L/eta/)(Ha10/sub 4/)/sub 2/, where Ha10/sub 4/ = C10/sub 4//sup -/, Bro/sub 4//sup -/, 10/sub 4//sup -/ (except for DMSO and H/sub 2/O), L is a neutral ligand, n = 4 for HMPTA and n = 5 for the remaining L, were investigated. X-ray crystallographic analysis established that the investigated perhalate complexes of uranyl with the same neutral ligands are isostructural. It was established that in the complexes studied the Ha10/sub 4//sup -/ anions are outer-sphere anions, and the value of the frequency of the antisymmetrical stretching vibration of the uranyl group does not depend on the nature of the perhalate anion. From the values obtained for ..nu../sub 3/ UO /SUP 2/2/ /sup +/, the values of the multiplicity and energy of the uranium-ligand bond were estimated.

Energy Technology Data Exchange (ETDEWEB)

This paper reports on pumped storage plants which have become an effective way for some utility companies that derive power from hydroelectric facilities to economically store baseload energy during off-peak hours for use during peak hourly demands. According to the Electric Power Research Institute (EPRI) in Palo Alto, Calif., 36 of these plants provide approximately 20 gigawatts, or about 3 percent of U.S. generating capacity. During peak-demand periods, utilities are often stretched beyond their capacity to provide power and must therefore purchase it from neighboring utilities. Building new baseload power plants, typically nuclear or coal-fired facilities that run 24 hours per day seven days a week, is expensive, about $1500 per kilowatt, according to Robert Schainker, program manager for energy storage at the EPRI. Schainker the that building peaking plants at $400 per kilowatt, which run a few hours a day on gas or oil fuel, is less costly than building ...

International Nuclear Information System (INIS)

The energy E(c/a) for a bcc element stretched along its [001] axis (the Bain path) has a minimum at c/a=1, a maximum at c/a=#sq root#(2), and an elastically unstable local minimum at c/a>#sq root#(2). An alternative path connecting the bcc and fcc structures is the rhombohedral lattice. The primitive lattice has R3m symmetry, with the angle #alpha# changing from 109.4 deg. (bcc), to 90 deg. (simple cubic), to 60 deg. (fcc). We study this path for the non-magnetic bcc transition metals (V, Nb, Mo, Ta, and W) using both all-electron linearized augmented plane wave and projector augmented wave VASP codes. Except for Ta, the energy E(#alpha#) has a local maximum at #alpha#=60 deg., with local minima near 55 deg. and 70 deg., the latter having lower energy, suggesting the possibility of a metastable rhombohedral state for these materials. We first examine the elastic stability of the 70 deg. minimum structure, and determine that only W is elastically stable in this ...

International Nuclear Information System (INIS)

The cell's cytoskeleton, providing the cell with structure and shape, consists of a complex array of structural proteins, including microtubules, microfilaments and intermediate filaments. Intermediate filaments play a crucial role in mechanotransduction and in providing mechanical stability to cells, in particular under large deformation. By utilizing molecular simulation, here we report a nanomechanical analysis of vimentin intermediate filament dimers, the basic building blocks of intermediate filaments. We describe a detailed analysis of the mechanical properties and associated deformation mechanisms, and find that mechanical stretch induces a transition from alpha-helices to beta-sheets, a phenomenon known as alpha-beta transition. A comparison of the Young's modulus predicted from simulation with experimental measurements is provided, and good agreement is found. We present an analysis of structural changes during deformation, domain unfolding patterns, rate ...

Energy Technology Data Exchange (ETDEWEB)

The IR double-resonance techniques IR/R2PI (infrared/resonant 2-photon ionization), IR/PIRI (infrared-photo-induced Rydberg ionization) and IR-photodissociation spectroscopy are valuable tools to investigate structure, vibrations, and dynamical processes of neutral and ionic hydrogen-bonded clusters containing aromatic molecules. In this paper we report on the application of the IR double-resonance techniques to determine the NH and OH stretching vibrations of 4-aminophenol and 4-aminophenol(H{sub 2}O){sub 1}, both in the neutral (S{sub 0}) and ionic (D{sub 0}) ground state. All vibrational frequencies obtained for 4-aminophenol and the cluster are compared with the values obtained from ab initio and DFT calculations. In the S{sub 0} state, a trans-linear arrangement of 4-aminophenol(H{sub 2}O){sub 1} is obtained containing an O-H. O hydrogen bond. In the D{sub 0} state an overlay of two spectra can be observed resulting from the trans-linear structure and a second ...

International Nuclear Information System (INIS)

The phase transition behaviour of polyethylene-b-poly(ethylene oxide) (PE-b-PEO) diblock copolymer with relatively short chain lengths has been studied on the basis of temperature dependent infrared and Raman spectral measurements and synchrotron WAXD/SAXS simultaneous measurements, from which the concrete structural changes were deduced successfully from the various levels of molecular chain conformation, chain packing mode and higher-order structure. The higher-order structure has been found to transform between lamella, perforated lamella, gyroid, cylinder and sphere structures. The inner structural changes occurring in the polyethylene and poly(ethylene oxide) parts have been related with these morphological changes. The morphological transition from lamella to gyroid occurs with keeping the crystalline state of polyethylene parts. This apparently curious transition can be interpreted reasonably by assuming the thermally-activated chain motion in the crystal lattice, which may play ...

International Nuclear Information System (INIS)

Perforated thermoplastic masks are used to provide patients immobilization. This procedure inserts a material in the path of the radiation beam, that attenuates and modifies the beam fluence and flatness. The present study evaluates the increase in skin dose as a result of using thermoplastic masks. Relative doses were measured on the surface of a solid water phantom, in the presence and absence of masks. These masks were stretched according to deformation patterns observed in clinical routine. The measurements were obtained with a plane-parallel chamber (Markus type 23343) and radiochromic film (EBT Gafchromic) for 6MV X-rays from a linear accelerator, and for a radiation beam from a cobalt therapy unit. The results showed that thermoplastic masks, whose thickness varied between 2 and 3 mm, increased the dose on the surface by a factor of 3. Due to the variations in the skin dose distribution, clinical procedures were suggested to minimize radiobiological damages ...

International Nuclear Information System (INIS)

Electron paramagnetic resonance (EPR), optical, infrared and Raman spectral studies have been carried out on vanadyl ions doped in polyvinylalcohol (PVA) films. The spin-Hamiltonian parameters (g and A) and the molecular orbital coefficients (#beta#_2"*"2 and k) have been evaluated. The values of spin-Hamiltonian parameters confirm that the vanadyl ions are present in PVA films as VO"2"+ molecular ions in an octahedral site with a tetragonal compression (C_4_v). The temperature variation EPR studies reveal that the variation of number of spins with temperature is in accordance with Boltzmann law. It is interesting to observe that the variation of susceptibility with temperature obeys Curie-Weiss law. The FT-IR and FT-Raman spectrum exhibits few bands, which are attributed to O-H, C-H, C-C and C-O groups of stretching and bending vibrations. The optical absorption spectrum exhibits two bands, which are assigned to "2B_2_g->"2B_1_g and "2B_2_g->"2E_g ...

Energy Technology Data Exchange (ETDEWEB)

California's pacific coast stretches roughly over 11.5 latitudinal degrees, extending from about 32.5{sup o}N to 44{sup o}N. There is nearly 900nm of California coastline offering superior opportunity for wave energy use. The longitudinal position of the coast shifts eastward at two distinct locations: Punta Gorda just south of Cape Mendecino in the north and Point Conception in the south. The change in longitudinal orientation in southern California also coincides with significant change in California's bathymetry. The tilts in the longitudinal coastal lines at the two points also define California wave zones into three areas: the short coastal line north of Punta Gorda, the long north and middle line between the two points, and the short line of the heavily populated southern coast. The northern and central zones are characterized by high waves of relatively low frequency; the southern coast is characterized by low waves of higher frequency. ...

Science.gov (United States)

The acid site distribution over large ZSM-5 crystals was analyzed using FTIR microscopy. Results of the analysis of the OH-stretching vibrations and of vibrations of pyridine adsorbed on Bronsted and Lewis acid sites were found to be in good agreement. The resolution which can be obtained using this novel technique is about 10-20 [mu]m. This limits the application to large crystals as analyzed in this study. Comparison of the results of IR microscopy with aluminum distributions obtained by electron microprobe analysis revealed that IR microscopy cannot resolve inhomogeneities on a scale smaller than the above-state limits. The results of both methods on a larger scale, however, are in very good agreement. Using a combination of both techniques, it is possible to obtain a clearer picture of the distribution of acid sites in large zeolite crystals, where electron microprobing gives the higher resolution, and IR microscopy allows the determination of the types of ...

Energy Technology Data Exchange (ETDEWEB)

This thesis presents the study of the slowing down process of fast heavy ions inside matter. In the framework of this research, the influence of the target density on the stopping process is investigated. Experiments on the interaction of {sup 48}Ca{sup 6+}-{sup 48}Ca{sup 10+} and {sup 26}Mg{sup 5+} ion beams with initial energies of 11.4 MeV/u and 5.9 MeV/u with solid and gaseous targets have been carried out. A novel diagnostic method, X-ray spectroscopy of K-shell projectile radiation, is used to determine the ion charge state in relation to its velocity during the penetration of fast heavy ions inside the stopping material. A spatially resolved analysis of the projectile and target radiation in solids is achieved for the first time. The application of low-density silica aerogels as stopping media provided a stretching of the ion stopping length by 20 - 100 times in comparison with solid quartz. The Doppler Effect observed on the projectile K-shell spectra is ...

Science.gov (United States)

We have measured the Raman isotropic profiles of the ?(C?N) band at 2235 cm(-1) for five solutions of ME6N (4-cyanophenyl-4'-hexylbenzoate) liquid crystal dissolved in CCl(4) in the range from x = 0.12 to 0.007 (x, mole fraction of ME6N) and then obtained the corresponding vibrational correlation functions, C(v)(t), by time Fourier transformation. The increase with dilution of the dephasing times ?(v) complies with the behavior of the nonmonotonic concentration dependence predicted by the fluctuation concentration model for this concentration range (x Rothschild, which, being based on the assumption that the environmental modulation is described by a stretched exponential decay e(-(t/?(0))(?)), is more appropriate for the interpretation of the vibrational correlation function arising from a distribution of relaxation processes caused, as in the present case, by the persistence of pseudonematic domains. With dilution the dispersion parameter ? and the average ...

Energy Technology Data Exchange (ETDEWEB)

A real-time neutron radiography facility was constructed including the capability of neutron tomography. The neutron beam was measured for total neutron flux ((1.0 +/- 0.2) x 10/sup 11/ m/(m/sup 2/-sec)), gold cadmium ratio (52 +/- 3) and effective neutron temperature (83/sup 0/C +/- 8/sup 0/C). The angular divergence or nonparallelism of the neutron beam was measured to be 2.3/sup 0/ +/- 0.1/sup 0/ thereby providing a means of quantifying the collimator effectiveness. The resolution capabilities of both static film and real-time neutron radiographs were quantified using a Fourier transform algorithm to calculate the modulation transfer function of both types of radiographs. The contrast sensitivity of both types of radiographs. The contrast sensitivity of both types of radiographs was measured as 3.1% for film and 4.0% for real-time radiographs. Two tomography algorithms, the simultaneous iterative reconstruction technique (SIRT) and the convolution method, were programmed on an ...

International Nuclear Information System (INIS)

Nop25 is a putative RNA binding nucleolar protein associated with rRNA transcription. The present study was undertaken to determine the mechanism of Nop25 localization in the nucleolus. Deletion experiments of Nop25 amino acid sequence showed Nop25 to contain a nuclear targeting sequence in the N-terminal and a nucleolar targeting sequence in the C-terminal. By expressing derivative peptides from the C-terminal as GFP-fusion proteins in the cells, a lysine and arginine residue-enriched peptide (KRKHPRRAQDSTKKPPSATRTSKTQRRRR) allowed a GFP-fusion protein to be transported and fully retained in the nucleolus. When the peptide was fused with cMyc epitope and expressed in the cells, a cMyc epitope was then detected in the nucleolus. Nop25 did not localize in the nucleolus by deletion of the peptide from Nop25. Furthermore, deletion of a subdomain (KRKHPRRAQ) in the peptide or amino acid substitution of lysine and arginine residues in the subdomain resulted in the loss of Nop25 nucleolar ...

Energy Technology Data Exchange (ETDEWEB)

For the performance analysis of Canadian deuterium uranium (CANDU) reactor shutdown system number 2 (SDS2), a computational fluid dynamics model of poison jet flow has been developed to estimate the flow field and poison concentration formed inside the CANDU reactor calandria. As the ratio of calandria shell radius over injection nozzle hole diameter is so large (1055), it is impractical to develop a full-size model encompassing the whole calandria shell. In order to reduce the model to a manageable size, a quarter of one-pitch length segment of the shell was modeled using symmetric nature of the jet; and the injected jet was treated as a source term to avoid the modeling difficulty caused by the big difference of the hole sizes. For the analysis of an actual CANDU-6 SDS2 poison injection, the grid structure was determined based on the results of two-dimensional real- and source-jet simulations. The maximum injection velocity of the liquid poison is 27.8 m/s and the mass fraction of ...

International Nuclear Information System (INIS)

The purified integral membrane protein, band 3, from human erythrocytes was inserted into egg lecithin liposomes. The insertion of band 3 was determined from thermal transition data from the analysis of the C-H stretching region bands recorded at temperatures from 25 to -22"oC. Raman spectra show that band 3 considerably broadens and lowers the thermal transition of egg lecithin liposomes, suggesting the insertion of band 3. The band 3-inserted liposomes were irradiated with gamma-rays (40 Gy) and the radiation target groups were determined by the analysis of the structural sensitive Raman bands in the 1600-1700 cm"-"1 (amide I), 1200-1300 cm"-"1 (amide III) and 550-1030 cm"-"1 (side chain amino groups) regions. The radiation-sensitive groups as identified from Raman spectra in the region 550-1030 cm"-"1 are tyrosines and cysteines. The radiation-induced changes in the secondary structure were determined from amide I and III bands. Quantitative estimation using the ...

Energy Technology Data Exchange (ETDEWEB)

Adsorpt1on of CH[sub 4] and coadsorption of CH[sub 4] and CO on differently treated magnesium oxide have been studied by FT-IR spectroscopy at 173-273 K. Five IR bands at 3008, 3000, 2900, 2890, and approximately 1306 cm[sup [minus]1] were observed when well-outgassed MgO was exposed to CH[sub 4] at 173 K. The bands at 3008 and 3000 cm[sup [minus]1] are assigned to a degenerate stretch vibration of CH[sub 4], and those at 2900 and 2890 cm[sup [minus]1] originate from an infrared-forbidden mode at 2917 cm[sup [minus]1] of free CH[sub 4]. These bands became noticeably stronger with the outgassing temperature of MgO but could be sufficiently reduced as MgO was pretreated in air or under water vapor. Adsorbed CO on MgO gives two IR bands at 2161 and 2155 cm[sup [minus]1] which exhibit a parallel variation with those bands of adsorbed CH[sub 4] with the different pretreatments of MgO. Coadsorption of CH[sub 4] and CO indicated that adsorbed CO can deplete part of the ...

International Nuclear Information System (INIS)

A next generation e"+-e"- linear collider in the TeV range can be converted into a #gamma#-#gamma# collider by converting it to e"--e"- operation and then generating #gamma#-rays via Compton backscattering with optical beams. This provides unique access to some areas of fundamental physics as well as highly desirable redundancy to the collisions. The required optical beam (with a wavelength of about 1 micron) must have very high peak power, (about 1 TW) as well as average power (about 10 kW). To achieve a 1 : 1 conversion from an electron to #gamma#-quantum, each micropulse must contain about one Joule and must be about one picosecond long, the micropulse peak power being about one Terawatt. To match the electron beam pulse structure, a macropulse consists of a sequence of about one hundred micropulses separated by about one nanosecond, and the macropulses am repeated at a rate of about 100 Hz. Thus, the time average power is about 10 kW propose and analyze a promising scheme to ...

International Nuclear Information System (INIS)

Greenland is the world's largest island, with an area of 2.2 million square kilometres, 80 % of which is covered by the ice sheet. The climate is Arctic, but as Greenland stretches 2600 km from north to south, there is a huge variability in climate, with temperature decreasing from south to north. Due to the influence of oceanic currents, the west coast is slightly warmer than the east coast. Precipitation also decreases strongly from the south to the north, and also with distance from the coast. Kangerlussuaq is located in the dry, continental area of central west Greenland. The bedrock of Greenland is dominated by Precambrian gneisses, with sedimentary rocks occurring in some areas of East and North Greenland, and smaller areas of basalts. All of Greenland has been glaciated several times and has thus been eroded and shaped by the ice, as it still is at the ice margin. Soils are generally thin, and especially in the gneiss regions rather poor in plant nutrients. ...

Science.gov (United States)

1. Contest rules The European Space Agency (ESA) is launching a public competition to find the most suitable names for its four Cluster II space weather satellites. The quartet, which are currently known as flight models 5, 6, 7 and 8, are scheduled for launch from Baikonur Space Centre in Kazakhstan in June and July 2000. Professor Roger Bonnet, ESA Director of Science Programme, announced the competition for the first time to the European Delegations on the occasion of the Science Programme Committee (SPC) meeting held in Paris on 21-22 February 2000. The competition is open to people of all the ESA member states (*). Each entry should include a set of FOUR names (places, people, or things from history, mythology, or fiction, but NOT living persons). Contestants should also describe in a few sentences why their chosen names would be appropriate for the four Cluster II satellites. The winners will be those which are considered most suitable and relevant for the Cluster II mission. ...