Theoretical Mode Research Articles

Polymer taper bridge for silicon waveguide to single mode waveguide coupling

Coupling of optical power from high-density silicon waveguides to silica optical fibers for signal routing can incur high losses and often requires complex end-face preparation/processing. Novel coupling device taper structures are proposed for low coupling loss between silicon photonic waveguides and single mode fibers are proposed and devices are fabricated and measured in terms of performance. Theoretical mode conversion models for waveguide tapers are derived for optimal device structure design and performance. Commercially viable vertical and multi-layer taper designs using polymer waveguide materials are proposed as innovative, cost-efficient, and mass-manufacturable optical coupling devices. The coupling efficiency for both designs is determined to evaluate optimal device dimensions and alignment tolerances with both silicon rib waveguides and silicon nanowire waveguides. Propagation loss as a function of waveguide roughness and metallic loss are determined and correlated to waveguide dimensions to obtain total insertion loss for the proposed taper designs. Multi-layer tapers on gold-sputtered substrates are fabricated through photolithography as proof-of-concept devices and evaluated for device loss optimization. Tapered waveguide coupling loss with Si WGs (2.74dB) was experimentally measured with high correlation to theoretical results.

Measuring Verbal Psychotherapeutic Techniques-A Systematic Review of Intervention Characteristics and Measures.

Language is one of the most important “tools” of psychotherapists. The working mechanisms of verbal therapeutic techniques, however, are still marginally understood. In part, this is due to the lack of a generally acknowledged typology as well as a gold standard for the assessment of verbal techniques, which limits the possibility of conducting studies focusing this topic. The present study reviews measures used in clinical research which assess directly observable dimensions of verbal interventions in a reliable manner. All measures were evaluated with respect to their theoretical foundation, research goals, assessment modes, and various psychometric properties. A systematic search in databases (PubMed, PsycInfo, PsycArticles, PSYNDEX, Web of Science, Embase) followed by an additional “snowballing” search covering the years 1940–2013 yielded n = 179 publications eligible for review. Within these publications, 34 measures were identified showing great heterogeneity regarding the aspects under study. Only two measures reached the highest psychometric standards and can be recommended for clinical use without any reservation. Central problems include deficiencies in the systematization of techniques as well as their partly ambiguous and inconsistent definitions. To promote this field of research, it will be important to achieve a consensus concerning the terminology, conceptions and measures of verbal interventions.

The Cognitive Function of Narratives

This essay will utilize the central historicist insight about the nature of the historical world and historical writing in articulating the cognitive function of narratives. It will argue that full-blown narratives are best understood as developmental portraits of a chosen entity/ unit in respect to its individuality. The argument will proceed through a critical analysis of the debate between Noel Carroll and David Velleman about the nature of the narrative connection and the question of whether the explanatory force of a narrative has to be understood in causal or emotional terms. I will side with the causalist in this respect but will also show that we need to be very careful in distinguishing between causal explanations underwritten by a theory and the use made of such causal accounts within the context of narratives concerned with explicating individuality. Accordingly, I agree with Mink that narratives are special cognitive instruments. Yet Mink’s characterization of narrative understanding as a “configurational mode of comprehension” that is strictly distinguished from the theoretical mode needs to be amended. Narrative understanding should be conceived as an autonomous and irreducible mode of comprehension. At the same time, it should be viewed as being dependent on a variety of theoretical perspectives it uses intricately.

Optical properties, lattice dynamics, and structural phase transition in hexagonal2H−BaMnO3single crystals

Optical properties and lattice dynamics of hexagonal $2H\ensuremath{-}\mathrm{BaMn}{\mathrm{O}}_{3}$ single crystals are studied experimentally in a wide temperature range by means of rotating analyzer ellipsometry and Raman scattering. The magnitude of the direct electronic band gap is found to be ${E}_{g}=3.2\phantom{\rule{0.16em}{0ex}}\mathrm{eV}$. At room temperature the far-infrared (IR) ellipsometry spectra reveal six IR-active phonons; two of them are polarized along the $c$ axis and four are polarized within the a-b plane. Seven phonon modes are identified in the Raman scattering experiments. Group theoretical mode analysis and complementary density functional theory lattice dynamics calculations are consistent with the $2H\ensuremath{-}\mathrm{BaMn}{\mathrm{O}}_{3}$ structure belonging to the polar $P{6}_{3}mc$ space group at room temperature. All observed vibrational modes are assigned to specific eigenmodes of the lattice. The neutron diffraction measurements reveal a structural phase transition upon cooling below ${T}_{C}=130\ifmmode\pm\else\textpm\fi{}5\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, which is accompanied by a lattice symmetry change from $P{6}_{3}mc$ to $P{6}_{3}cm$. Simultaneously, at temperatures below ${T}_{C}$ several additional IR- and Raman-active modes are detected in experimental spectra. This confirms the occurrence of a structural transition, which is possibly associated with the appearance of electrical polarization along the $c$ axis and a previously known tripling of the primitive cell volume at low temperatures.

Optical properties and lattice dynamics of CuZnGeSe quaternary semiconductor: A density‐functional study

AbstractDensity‐functional calculations of the electronic band structure, optical properties, and lattice dynamics of kesterite CuZnGeSe semiconductor (space group ) are reported. Theoretical optical properties of the material are shown to agree quantitatively with available spectroscopic ellipsometry experimental data that allow detailed interpretation of the main spectral features around the fundamental absorption edge. A good agreement between theoretical and experimental vibrational mode frequencies is also established and the assignment of observed phonon modes to specific lattice eigenmodes is performed.

Synthesis, antimicrobial activity and molecular docking studies of pyrano[2,3-d]pyrimidine formimidate derivatives

A new series of ten poly-functionalized pyrano(2,3-d)pyrimidine formimi- date derivatives were successfully synthesized. All the synthesized compounds were characterized by 1 H NMR, 13 C NMR, HRMS, and FT-IR spectral analysis. All the synthesized compounds were evaluated for their antimicrobial activity by using the well plate method and MIC by the broth micro dilution method against the strains of bacteria as well as fungus. Four compounds exhibited good to excellent antimicrobial activity. The theoretical binding mode of the target molecules was evaluated by docking studies, which revealed a new molecular scaffold for enhancing the antimicrobial activity of compounds. Graphical Abstract Studies on synthesis, characterization, antimicrobial activity, and molecular docking of novel pyrano(2,3-d)pyrimidine formimidate derivatives (10) are reported. Four of the compounds exhibited excellent activity.

Surface contact stress-based nonlinear virtual material method for dynamic analysis of bolted joint of machine tool

The components of machine tools are mainly fixed and connected by bolts. The performance of the assembly can be affected by the dynamic characteristics of the bolted joints. This paper presents a nonlinear virtual material method based on surface contact stress to describe the bolted joint for accurate dynamic performance analysis of the bolted assembly. Fractal geometry theory is used to describe the surface topography. The elastic modulus and shear modulus of one micro-contact are derived based on fractal contact theory. The equivalent elastic modulus, Poisson ratio, and density of the bolted joint can be obtained through the weighted mean method. In order to obtain the stress distribution, the contact surface is assumed flat in the macro-scale, and the uneven distribution of contact stress can be obtained by the finite element method (FEM). The contact surface can be divided into several sections, and the parameters of a virtual material layer can be determined based on the mean contact stress. Both theoretical and experimental results for a bolted joint are obtained for a box-shaped specimen under equal pre-tightening force and bending moment effect. The results show that the theoretical mode shapes are in good agreement with the experimental mode shapes. The relative errors between the theoretical and experimental natural frequencies are less than 4.41%, which indicates that the present nonlinear virtual material method is appropriate for the bolted joint in modeling CNC machine tools.

Terahertz Absorption Spectra Simulation of Glutamine Based on Quantum-Chemical Calculation

With simulation of absorption spectra in THz region based on quantum-chemical calculation, the THz absorption features of target materials can be assigned with theoretical normal vibration modes. This is necessary for deeply understanding the origin of THz absorption spectra. The reliabilities of simulation results mainly depend on the initial structures and theoretical methods used throughout the calculation. In our study, we utilized THz-TDS to obtain the THz absorption spectrum of solid-state L-glutamine. Then three quantum-chemical calculation schemes with different initial structures commonly used in previous studies were proposed to study the inter-molecular interactions' contribution to the THz absorption of glutamine, containing monomer structure, dimer structure and crystal unit cell structure. After structure optimization and vibration modes' calculation based on density functional theory, the calculation results were converted to absorption spectra by Lorentzian line shape function for visual comparison with experimental spectra. The result of dimmer structure is better than monomer structure in number of absorption features while worse than crystal unit cell structure in position of absorption peaks. With the most reliable simulation result from crystal unit cell calculation, we successfully assigned all three experimental absorption peaks of glutamine ranged from 0.3 to 2.6 THz with overall vibration modes. Our study reveals that the crystal unit cell should be used as initial structure during theoretical simulation of solid-state samples' THz absorption spectrum which comprehensively considers not only the intra-molecular interactions but also inter-molecular interactions.

DFT and SERS Study of Adsorption of 1,4-Dimethoxy-2-nitro-3-methylanthracene-9,10-dione onto Silver Nanoparticles

Surface-enhanced Raman scattering (or spectroscopy), commonly known as SERS, has been employed to investigate the adsorption mechanism and orientation of 1,4-dimethoxy-2-nitro-3-methylanthracene-9,10-dione (DMNMAD) molecule onto silver. Silver nanoparticles (Ag NPs) were synthesized based on a solution combustion method using citric acid as a fuel. Scanning electron microscopy and transition electron microscopy studies confirm the crystalline nature and morphology of the synthesized silver nanoparticles. Theoretical normal Raman spectra (nRs) and SERS spectra of the DMNMAD molecule, simulated based on DFT/B3PW91 level of theory were validated experimentally. Experimental and theoretical vibrational modes correlate well, confirming the reliable assignments of the vibrational bands. Enhancement of C=O stretching and C–H in-plane vibrational modes in the SERS spectrum indicates the ‘stand-on’ orientation of the molecule on the silver nanoparticles after adsorption. The frontier molecular orbitals confirm the charge transfers between the molecule and silver nanoparticles following the process of adsorption. As anthraquinone derivatives have been recently used as potent anti-tumour drugs, the adsorption studies reported in the current investigation can pave way to the potential application of DMNMAD in drug delivery.

Deciphering acoustic emission signals in drought stressed branches: the missing link between source and sensor.

When drought occurs in plants, acoustic emission (AE) signals can be detected, but the actual causes of these signals are still unknown. By analyzing the waveforms of the measured signals, it should, however, be possible to trace the characteristics of the AE source and get information about the underlying physiological processes. A problem encountered during this analysis is that the waveform changes significantly from source to sensor and lack of knowledge on wave propagation impedes research progress made in this field. We used finite element modeling and the well-known pencil lead break source to investigate wave propagation in a branch. A cylindrical rod of polyvinyl chloride was first used to identify the theoretical propagation modes. Two wave propagation modes could be distinguished and we used the finite element model to interpret their behavior in terms of source position for both the PVC rod and a wooden rod. Both wave propagation modes were also identified in drying-induced signals from woody branches, and we used the obtained insights to provide recommendations for further AE research in plant science.

Meiotic chromosome configurations in triploid progeny from reciprocal crosses between wild-type diploid and natural tetraploid loach Misgurnus anguillicaudatus in China.

Here, we showed meiotic chromosome configurations prepared from oocyte germinal vesicles and spermatocytes of triploid loaches produced from reciprocal crosses between wild-type diploids (2n = 50) obtained from Dalian, Liaoning Province, China and natural tetraploids (4n = 100) from Chibi, Hubei Province, China. Major meiotic cells in triploids comprised 25 bivalents and 25 univalents, but cells with one to five trivalents were also observed. When three homologous chromosomes bearing nucleolar organizing regions (NOR) were identified with the detection of signals or positive sites by silver staining, chromomycin A3 staining and fluorescence in situ hybridization with a 5.8S + 28S rDNA probe, two third of selected triploid cells gave a configuration including one bivalent with two NORs (association of two homologous chromosomes) and one univalent with one NOR. However, other triploid cells showed three univalent each of which had one NOR, suggesting a failure of synapsis between homologous chromosomes. These results suggested that triploid female and male should produce aneuploid gametes with the theoretical mode at 1.5n (37 or 38 chromosomes).

Linear Polarized Transmission Resonance Raman Studies in Fruits: Experimental Versus Model Calculations.

A linear polarized transmission resonance Raman spectroscopic technique was developed to measure the depolarization ratio of different β-carotene Raman bands in carrot roots and mangos. Basically, this optical property was measured as a function of the vegetal tissue thickness and fruit postharvest lifetime. In general, the depolarization ratio increases as the sample optical thickness does and decreases as the fruit postharvest lifetime increases. In addition, a previous theoretical model was extended by considering the light state of polarization to obtain the depolarization ratio as a function of the sample absorption and scattering coefficient. It was shown how the reported theoretical model is able to satisfactorily describe the fruit optical parameter dependence on both the sample thickness and its postharvest time. Finally, the advantages and limitations of the present technique and theoretical mode are discussed.

Abnormal Temperature Dependence of Mobility in a Disordered System With Traps: Experiment and Theory

Mobility μ is essential in electronic and optoelectronic devices. Abnormal temperature T dependence of the carrier mobility μ of poly [2-methoxy-5-2-ethyl-hexyloxy]-p-phenylenevinylene (MEH-PPV)/InP nanocrystal composites was observed using the time-of-flight technique. The slope of ln(μ) as a function of 1/T <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> dramatically changed before and after the critical temperature T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> of 283 K. Using the variable range hopping theoretical mode, a new trap-filling factor (FF) was proposed as a key parameter to illustrate the effect of the trap on the mobility. According to FF, there are three regions. When FF ≫ 1 and FF≪1, the carrier behavior follows the Fermi and Boltzmann distributions, respectively. When FF~1, the derived transition temperature of 282.4 K represents a transition point from Fermi to Boltzmann distribution, which is consistent with T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> in the experiment. Finally, a universal dependence of ln(μ) on T was concluded based on FF in a disordered system with traps.

Fast convergence equalization algorithm for mode division multiplexing system

We propose a theoretical mode division multiplexing (MDM) transmission model in a few mode fibers and numerically simulate the effects of mode coupling and modal dispersion on the transmitted signal. An adaptive signal processing with multiple-input multiple-output equalizers based on recursive least squares constant modulus algorithm (CMA) is proposed and demonstrated. The simulation results show that the mode signals are equalized sufficiently with a faster convergent speed than regular CMA. The equalization algorithm presented is more adaptive to complicated channels and applicable to the MDM system.

Theology, Science, and Technology: Framing an Encounter in Light of Lonergan and Ricœur

This article proposes a theological approach to the encounter between theology and the world of science and technology. A suitable locus for encounter is the different partners' shared commitment to the desire to understand. I draw on the work of both Bernard Lonergan and Paul Ricœur to describe understanding as the enactment of a pattern of cognitional operations. However, the theoretical mode of understanding proper to science is distinct from the practical mode of understanding proper to technology. Lonergan's elaboration of the “intellectual” pattern of operations is drawn on to enhance an encounter with science, while Ricœur's elaboration of the “action” pattern is drawn on to enhance an encounter with technology.

Buoyancy of some Palaeozoic ammonoids and their hydrostatic properties based on empirical 3D-models

The interpretation of the function of the ammonoid phragmocone as a buoyancy device is now widely accepted among ammonoid researchers. During the 20th century, several theoretical models were proposed for the role of the chambered shell (phragmocone); accordingly, the phragmocone had hydrostatic properties, which enabled it to attain neutral buoyancy, presuming it was partially filled with gas. With new three-dimensional reconstructions of ammonoid shells, we are now able to test these hypothetical models using empirical volume data of actual ammonoid shells. We investigated three Palaeozoic ammonoids (Devonian and Carboniferous), namely Fidelites clariondi, Diallagites lenticulifer and Goniatites multiliratus, to reconstruct their hydrostatic properties, their syn vivo shell orientation and their buoyancy. According to our models, measurements and calculations, these specimens had aperture orientations of 19°, 64° and 125° during their lives. Although none of our results coincide with the aperture orientation of the living Nautilus, they do verify the predictions for shell orientations based on published theoretical models. Our calculations also show that the shorter the body chamber, the poorer was the hydrodynamic stability of the animal. This finding corroborates the results of theoretical models from the 1990s. With these results, which are based on actual specimens, we favour the rejection of hypotheses suggesting a purely benthonic mode of life of ammonoids. Additionally, it is now possible to assess hydrodynamic properties of the shells through ontogeny and phylogeny, leading to insights to validate theoretical modes of life and habitat through the animal's life.

Manufacturability Improvement of Fiber Aluminum Laminate by Forming the Effective Crystallographic Texture in V95 Alloy Sheets

Theoretical notions and formation modes of the crystallographic texture of the sheets made of the V95pch aluminum alloy, which provides the intensification of formation of detail made of fiber aluminum laminates by stretch-forming. The deformation texture (orientations S and Bs) is formed during hot rolling; it enhances during further cold rolling. The recrystallization texture is formed during annealing (orientations {011}〈100〉 and {023}〈100〉). An increase in the limiting stretch-forming coefficient after cold rolling is provided by two-stage annealing, which includes rapid heating at the continuous heat treatment line and subsequent complete annealing in an in-and-out furnace with slow cooling.

Therapeutic Alliance With Youth in Residential Care: Challenges and Recommendations

The therapeutic alliance has consistently been shown to be a strong predictor of therapy outcome across theoretical orientations, presenting problems, and modes of treatments in youth (Shirk & Karver, 2003; Shirk, Karver, & Brown, 2011). As the intensity of treatment increases from outpatient to inpatient to residential, the difficulty in alliance formation also increases. Multiple factors can affect a youth’s ability to form an alliance in a residential facility. Internal factors, such as the youth’s psychopathology and temperament, may play a role. Familial factors, including abuse or neglect are common. Community factors, such as being removed from the home, could play a part. Institutional factors, including moving from a lower level to a higher level of treatment, could be another piece of the puzzle. Therapist factors may also play a role.

A manufacturability improvement of glass-fiber reinforced aluminum laminate by forming an effective crystallographic texture in V95 alloy sheets

Theoretical notions and formation modes of the crystallographic texture of sheets made of the V95pch aluminum alloy, which intensifies the formation of parts made of glass-fiber reinforced aluminum laminates by stretch forming, are presented. The deformation texture (orientations S and Bs) is formed during hot rolling; it becomes stronger during further cold rolling. The recrystallization texture is formed during annealing (orientations [011]〈100〉, [023]〈100〉). An increase in the limiting stretch-forming coefficient after cold rolling is provided by two-stage annealing, which includes rapid heating at the continuous heat treatment line and subsequent complete annealing in an in-and-out furnace with slow cooling.

Identification of ustiloxins in false smut balls of rice based on high performance liquid chromatography-high resolution mass spectrometry

A sensitive method was developed for the simultaneous identification of five ustiloxins in the false smut balls of rice by high performance liquid chromatography-linear ion trap/orbitrap high resolution mass spectrometry (HPLC-LTQ/Orbitrap MS). The samples were extracted with deionized water under ultrasonic condition for 10 min, then purified by a strong cation exchange column (PCX). The ustiloxins were separated on an Xselect HSS T3 column (150 mm x 2.1 mm, 3.5 μm) by using 0.1% (v/v) formic acid water solution and methanol as mobile phases with gradient elution at a flow rate of 0.3 mL/min. The full scan range was m/z 200-1 000. The confirmatory analysis of the target compounds was carried out by the accurate mass of quasi-molecular ion, isotope abundance ratio and qualitative fragments. The results showed that the five ustiloxins (A, B, C, D and F) were identified from the false smut balls with mass accuracy less than 1 x 10(-6) (1 ppm) and the absolute values of the deviation of isotope abundance ratio were not more than 3.3%. The product ions were consistent with the theoretical fragment mode. The recoveries were 90% to 105%. This method is accurate and sensitive for the simultaneous identification of the five ustiloxins, which can provide technical means for the research of the ability in toxin producing by Ustilaginodea virens.