Dielectric resonator antennas(DRAs) offer some attractive characteristics over conventional microstrip antennas, such as small size, low profile, light weight, ease of excitation, and high radiation efficiency at higher frequency bands. Since DRAs attract more and more attention, theoretical analysis have been insufficient to simulate various configurations of dielectric resonator antennas. Therefore some researchers introduce numerical methods to analyze DRAs, such as Finite Difference Time Domain (FDTD) method, Method of Moment (MoM), Finite Element Method (FEM). In this author, we apply two kinds of methods, including FDTD and MoM, to analysis DRA and compare the results applied these two methods. Then we simulate various configurations of dielectric resonator antennas using FDTD method. About designing the DRA construction, in this author we applied an equivalent approach to solve approximate dimensions of DRAs, and then we obtain accurate dimensions using FDTD method. In this author¡Aa DRA work at 5.8GHz have been proposed, then we using a L-shaped patch to increase impedance bandwidth. Above all, we hope to built a fast and accurate procedure to solve the resonant frequency, bandwidth, and far field pattern of DRAs. And to supply the engineer to reduce time consume in design DRAs.

Structure properties of water clusters are investigated in this study by means of molecular dynamics simulations. The oxygen density profile, dipole moment and hydrogen bond properties of water clusters are all examined. The temperature dependence and size dependence of the structure properties are also explored in the present study. Upon the molecular dynamics simulations, the flexible three-centered (F3C) water potential is used to model the inter- and intra-actions of the water molecule. It is found that as the temperature rises, the density of the oxygen and the average number of hydrogen bonds per water molecule will decrease. The effect of cluster size, however, is less significant on the structure properties. The differences between the structural properties for the surface region and those for the interior region of the cluster are also investigated. It is found that as the temperature rises, the average number of hydrogen bonds per water molecule decreases, but the ratio of surface water molecules increases. After comparing the water densities in interior regions and the average number of hydrogen bonds in those regions, we find there is no apparent size effect on water molecules in the interior region, whereas the size of the water cluster has a significant influence on the behavior of water molecules at the surface region.

This thesis investigates the relations between (1) free stream velocity, blade radius as well as the number of blades, and (2) generated torque, power and efficiency in the design of a water turbine. In the study, blade element momentum theory (BEMT) is exploited to devise the shape of the horizontal water turbine. Further, a CFD package is in used to simulate the flow and pressure fields. The result shows that torque and power generated by turbine vary with such parameters as inlet velocity and blade radii. As the number of blade increases, the generated power is also on the rise but to a lessened degree.It is due to the fact that fluid can hardly flow into the cross section as the blade number increases, which brings about lower cross-section velocity. So the rotational speed should decline as a consequence to obtain the angle of attack satisfying the greatest lift-drag ratio. The largest power efficiency is thus gained.

The research described in this thesis examined age- and strength training-related changes in Achilles tendon stiffness and plantarflexor force production in prepubertal children. The measurement of both Achilles tendon stiffness and muscular force production requires in vivo moment arm lengths to be known. Currently, this is possible only by using expensive and time-consuming medical imaging methodologies. Therefore, the predictability of the Achilles tendon moment arm from surface anthropometric measurements was assessed in the first experimental study (Chapter 3). The results demonstrated that a combination of foot length and the distance between the calcaneal tuberosity and 1st metatarsal head could explain 49% of the variability in Achilles tendon moment arm length in 5 – 12 year-old children. This was considered to be unacceptable for further use, thus an ultrasound-based method was decided upon for obtaining moment arm length in subsequent experimental studies. In the second and third experimental studies (Chapters 4 and 5), age-related changes in tendon mechanical and structural properties were documented and their relationship with changes in force production ability were examined in prepubertal children (5 – 12 years) and adult men and women. In Chapter 4, Achilles tendon stiffness was shown to increase with age through to adulthood, and that changes in tendon stiffness were strongly and independently associated with body mass (R2 = 0.58) and peak force production capacity (R2 = 0.51),which may provide the tendon with an increasing mechanical stimulus for growth and microadaptation. These increases in tendon stiffness were associated with a greater increase in tendon CSA (~105%) than that found for tendon length (~60%), in addition to an increase in Young’s modulus (~139%), suggesting that gross increases in tendon size as well as changes in its microstructure underpinned the increase in stiffness. In Chapter 5, the relationships between Achilles tendon stiffness and both electro-mechanical delay (EMD) and rate of force development (RFD) were determined during maximal isometric plantarflexion contractions. Moderate correlations were found between tendon stiffness and both EMD (r = -0.66) and RFD (r = 0.58). RFD was significantly better predicted when muscle activation (estimated as the rate of EMG rise) was included in a regression model. These data clearly show that increases in tendon stiffness with age through to adulthood are associated with decreases in EMD and increases in RFD, and that the rate of muscle activation has an additional influence on RFD during growth. Given that 1) Achilles tendon stiffness was lower in children than adults, 2) this lower stiffness was associated with a longer EMD and slower RFD, and 3) that strength training in adults had previously been shown to increase tendon stiffness and RFD, the adaptability of the developing Achilles tendon to a resistance training programme, and consequence of the potential changes on force production capacity were examined in the final experimental study (Chapter 6). Significant increases in Achilles tendon stiffness and Young’s modulus were found after 10 weeks of twice-weekly plantarflexor strength training in 8-9 year-old boys and girls, which demonstrates that the larger muscle force production provided a sufficient stimulus for tendon microadaptation. The training also resulted in a decrease in EMD, which was moderately correlated with the change in tendon stiffness (r = 55), but no change in RFD. Thus, the increasing tendon stiffness with training was associated with a decreasing EMD, but had no detectable effect on RFD. This would likely have a significant effect on the performance of tasks requiring rapid muscle force production. Together, the results of the present series of investigations demonstrate that the tendon loading experienced from both normal ageing and overloading (strength training) can increase tendon stiffness in children, and that these changes have a detectable effect on rapid force production.

The ACME collaboration aims to measure the eEDM via Ramsey spectroscopy of a cryogenic beam of ThO molecules in their metastable H state. This thesis describes the launch of this new experimental effort. A set of diode lasers has been built to address all the necessary ThO transitions. The laser frequencies were stabilized to a stable reference laser via a \(Fabry-P\acute{e}rot\) transfer cavity. A measurement of the magnetic dipole moment of the H state has been performed that is complementary to a previous measurement by the collaboration. This value is important for determining the sensitivity of the H state to magnetic fields, which can be a source of noise and systematic errors in the eEDM measurement. Experimental efforts to prepare the coherent superposition of the \(M = \pm1\) Zeeman sublevels in the H,J = 1 state that is the starting point of the eEDM experiment using transitions to the G state resulted in a better understanding of transitions between \(\Omega\)-doublet states in an electric field. This led to a new technique for normalizing out shot-to-shot fluctuations in the molecular beam flux, which has also been demonstrated experimentally. / Physics

The 2008 measurement of the electron magnetic moment is the most precisely measured property of an elementary particle, with an astonishing precision of 0.28 parts per trillion. It makes possible the most precise determination of the fine structure constant and the most precise test of quantum electrodynamics and the Standard Model of particle physics. This thesis describes the installation of a new apparatus designed to have improved stability, more optimal control over the radiation field and inhibited spontaneous emission, and narrower resonance lines. / Physics

The Standard Model of particle physics is wonderfully successful in its predictions but known to be incomplete. It fails to explain the existence of dark matter, and the fact that a universe made of matter survived annihilation with antimatter following the big bang. Extensions to the Standard Model, such as weak-scale Supersymmetry, provide explanations for some of these phenomena by asserting the existence of new particles and new interactions that break symmetry under time-reversal. These theories predict a small, yet potentially measurable electron electric dipole moment (EDM), $d_e$, that also violates time-reversal symmetry. Here, we report a new measurement of the electron EDM in the polar molecule thorium monoxide (ThO): $d_e = -2.1 \pm 3.7stat \pm 2.5syst x 10-29$ e cm, which corresponds to an upper limit of $|d_e| <8.7 x 10-29$ e cm with 90 \% confidence. This is more than an order of magnitude improvement in sensitivity compared to the previous limit. This result sets strong constraints on new physics at an energy scale (TeV) at least as high as that directly probed by the Large Hadron Collider. The unprecedented precision of this EDM measurement was achieved by using the high effective electric field within ThO to greatly magnify the EDM signal. Valence electrons travel relativistically near the heavy thorium nucleus and experience an effective electric field of about 100 GV/cm, millions of times larger than any static laboratory field. The reported measurement is a combination of millions of separate EDM measurements performed with billions of ThO molecules in a cold, slow buffer gas beam. Other features of ThO, such as a near-zero magnetic moment and high electric polarizability, allow potential systematic errors to be drastically suppressed and ensure the accuracy of our measurement. / Physics

Bakalauro darbe kompiuterine programa Matchad ištirta trigometrinės sumos fiksuotiems lambda ir sigma, reikšmių priklausomybė nuo sumuojamų dėmenų skaičiaus, mažiausių kvadratų metodu užrašyta aproksimacinė funkcija ir įvertinta paklaida, gauti rezultatai pateikti grafiškai. / In this work, by the program Mathcad, the dependence of the sum from the number of summands, for fixed parameters sigma and lambda, is obtained. By the method of the smallest squares, approximation function is given. Also all results are presented by graphics. .

Bakalauro darbe nagrinėjama periodinė dzeta funkcija pusplokštumėje σ>1, apibrėžiama Dirichlė eilute ζ(s,a)=∑_(m=1)^∞▒a_m/m^s Periodinė kompleksinių skaičių seka apibrėžiama tokiu būdu a={1, -1, i, -i}, kurios periodas k=4. Darbo rezultatas yra periodinės dzeta funkcijos antrojo momento asimptotika.

The maximum entropy moment closure for the two-moment approximation of the radiative transfer equation is presented. The resulting moment equations, known as the M1 model, are solved using a finite-volume method with adaptive mesh refinement (AMR) and two Riemann-solver based flux function solvers: a Roe-type and a Harten-Lax van Leer (HLL) solver. Three different boundary schemes are also presented and discussed. When compared to the discrete ordinates method (DOM) in several representative one- and two-dimensional radiation transport problems, the results indicate that while the M1 model cannot accurately resolve multi-directional radiation transport occurring in low-absorption media, it does provide reasonably accurate solutions, both qualitatively and quantitatively, when compared to the DOM predictions in most of the test cases involving either absorbing-emitting or scattering media. The results also show that the M1 model is computationally less expensive than DOM for more realistic radiation transport problems involving scattering and complex geometries.