The characteristics of a laser-induced shock wave plasma which was induced by focusing a laser pulse on the surface of glass samples were examined by using radiation from a XeCl excimer laser and a TEA CO2 laser under reduced pressure of around 1 Torr. It was observed that shock wave plasma could not be generated by the TEA CO2 laser on low-melting-point glass because of the lack of expulsion from the sample surface. On the other hand, with the use of an excimer laser, shock wave plasma can be generated, even in low-melting-point glasses, thus making it amenable for spectrochemical analysis. Initial quantitative analysis was performed on a number of glass samples, and a linear calibration curve with a slope of near unity was obtained at a certain pressure. Furthermore, light elements such as Li and B, which are usually difficult to observe by the X-ray fluorescence method, were also successfully detected with a very low detection limit of less than 10 ppm. Other detection limits and background equivalent concentrations of almost all elements usually contained in glass, such as Na, Mg, Al, K, Ca, Ti, Zn, Zr, and Ba, were also presented. These results showed that the detection limit is much lower than those usually required for glass analysis.

A method of index measurement, the so-called rn-line technique has been applied to measure the refractive index of planar waveguides fabricated by ion exchange method in BK7 substrate. By placing a prism coupler on the surface of the planar waveguide, the coupling angle of modes guided in the waveguide was measured. The prism has apex angle of 44.9° and is made of ZnSe with refractive index 2.59073 . The values of the coupling angles were then processed mathematically to obtain the effective indices of the guided modes. The number of modes guided in the waveguide depends on the duration of ion exchange process, and the effective refractive indices have been determined for the respective modes. The result for zero order mode, ranging from 1 .5183 to 1 .6887 for TM modes and from 1 .51 82 to 1 .6891 for TE modes. On the other hand, for the duration of ion exchange process of 48 hours, five modes were guided in the waveguide and the effective refractive indices were 1.6887; 1 .6167; 1.5818; 1 .5649 and 1 .5465 for zeroth, the first, the second, the third and the fourth modes, respectively. The use of the rn-line technique has been proved to be simple and effective with high accuracy in the characterization purpose of waveguides.

We study the 'Large Volume Scenario' on explicit, new, compact, four-modulus Calabi-Yau manifolds. We pay special attention to the chirality problem pointed out by Blumenhagen, Moster and Plauschinn. Namely, we thoroughly analyze the possibility of generating neutral, non-perturbative superpotentials from Euclidean D3-branes in the presence of chirally intersecting D7-branes. We find that taking proper account of the Freed-Witten anomaly on non-spin cycles and of the Kähler cone conditions imposes severe constraints on the models. Nevertheless, we are able to create setups where the constraints are solved, and up to three moduli are stabilized. ArXiv ePrint: 0811.4599 JHEP07(2009)074 C Fourth model: a matterless model 34 C.1 The resolved P 4 1,1,1,3,3 (9) /Z 3 : 0 0 0 2 1 geometry 35 C.2 Moduli stabilization 36 1 Introduction The 'Large Volume Scenario' (LVS), developed in [1] is a new strategy for stabilizing the Kähler moduli in IIB Calabi-Yau orientifold compactifications. This strategy can be seen as a cousin of the KKLT strategy [2]. In both cases, one first stabilizes the axio-dilaton and complex structure moduli by means of the flux induced Gukov-Vafa-Witten superpotential, and then one tries to stabilize the Kähler moduli by non-perturbative effects such as E3branes (Euclidean D3-branes), and gaugino condensation. The key difference between these two strategies lies in the fact that the LVS admits non-supersymmetric anti-de Sitter minima, whereby the Calabi-Yau volume is exponentially large w.r.t. the size of the E3brane, and, at fixed g s , it is independent of the flux superpotential W 0 . This latter fact implies that this non-perturbative stabilization of the Kähler moduli will not mess up the complex structure stabilization. Other advantages of this scenario are explained in [3].The key requirement to construct an LVS model, is to find a Calabi-Yau threefold with h 2,1 > h 1,1 > 1, and such that the volume of the manifold is driven by the volume of a single 'large' four-cycle, and that the rest of the four-cycles contribute negatively to the overall volume. This structure has been dubbed the 'Swiss cheese' structure. Because it is possible to make cycles small while keeping the CY large, we can have E3-instantons that make large contributions and have a large volume vacuum. These instanton effects now becoming important, actually compete against α ′ corrections to the Kähler potential. Having these 'small', shrinkable cycles also serves another useful purpose. If one places MSSM-like stacks of D7-branes on them, by going to this large volume limit where these are made small, one effectively decouples the gauge theory on the brane from the UV dynamics encoded by the rest of the Calabi-Yau data. In this way, one addresses the comment in [4], which points out a drawback of generic models: Namely, that making the volume of the CY large will typically force one to scale up the cycles on which branes are wrapped.In [5], Blumenhagen et al have shown that the standard two-step model building paradigm, where ...

No abstract