Effects of Magnetic Fields on Proto-Neutron Star Winds

We discuss effects of magnetic fields on proto-neutron star winds by performing numerical simulation. We assume that the atmosphere of proto-neutron star has a homogenous magnetic field (ranging from ~10^{12} G to ~10^{15} G) perpendicular to the radial direction and examine the dependence of the three key quantities (dynamical time scale, electron fraction, and entropy per baryon) for the successful r-process on the magnetic field strength. Our results show that even with a magneter-class field strength, ~10^{15} G, the feature of the wind dynamics varies only little from that of non-magnetic winds, and that the condition for successful r-process is not realized.Comment: submitted to Progress of Theoretical Physics. 28 pages, 13 figure

On existence of matter outside a static black hole

It is expected that matter composed of a perfect fluid cannot be at rest outside of a black hole if the spacetime is asymptotically flat and static (non-rotating). However, there has not been a rigorous proof for this expectation without assuming spheical symmetry. In this paper, we provide a proof of non-existence of matter composed of a perfect fluid in static black hole spacetimes under certain conditions, which can be interpreted as a relation between the stellar mass and the black hole mass.Comment: 4pages, final version accepted for publication in Journal of Mathematical Physic

Grafted polymer monolayer brush as electron beam resist

This thesis focuses on the nanofabrication process using novel electron beam resists. First, in Chapter 3 and Chapter 4, the nanofabrication process using grafted polymer monolayer brush as e-beam resist was examined. Then, in Chapter 5, characteristics of the mixture of polystyrene (PS) and polydimethylsiloxane (PDMS) as negative tone e-beam resist with high dry etch resistance were studied. The main advantage of grafted polymer brush as electron beam is that it is applicable on non-flat or irregular surfaces. Although nanofabrication on non-flat surfaces has a lot of applications such as nanofabrication on AFM tips and optical fibers, there is no versatile method for nanofabrication on non-flat surfaces. In this thesis, nanofabrication on non-flat surfaces of an AFM cantilever was demonstrated using grafted polymer brush. Grafted polymer brush includes grafted poly(methyl methacrylate) (PMMA) brush and grafted PS brush; PMMA brush was used as negative tone e-beam resist, and PS monolayer brush was used as both positive and negative tone e-beam resist in this study. When PMMA brush and PS brush are used as negative tone resist, a development method plays an important role. Although solvent development is the most common development method to develop thick PMMA film or PS film as negative tone resist, solvent does not work as a developer for PMMA brush and PS brush. Instead, thermal treatment was used to develop monolayer PMMA brush or PS brush to achieve negative tone behavior. Since cross-linked PMMA and PS has higher thermal stability than uncross-linked ones, only unexposed polymer was vaporized at proper temperature. Thus, the polymer brush works as negative tone resist. Positive tone behavior of PS brush was achieved by changing the development method. When PS is exposed to electron beam, it loses the resistance to wet etch. Therefore, when the PS brush was grafted on an intermediate Al mask layer and developed by diluted HF solution, Al layer underneath the exposed PS brush was etched directly by HF. Since Al layer underneath unexposed PS was protected from wet etch, the resulting patterns on the Al mask layer showed negative tone behavior. In Chapter 5, the mixture of PS and PDMS was studied as negative tone e-beam resist with high dry etch resistance. High dry etch resistance is one of the most important characteristics of e-beam resist because resist with high resistance can be used as dry etch mask, and the patterns on the resist can be transferred to the substrate using direct dry etch. Recently, hydrogen silsesquioxane (HSQ) has been vigorously studied as negative tone resist with high dry etch resistance and high resolution. However, it has several drawbacks: it is very expensive, the shelf life is very short, and the processes should be done very quickly to obtain reproducible results. Here, it was demonstrated that PS that contains PDMS can be used as negative tone e-beam resist with high dry etch resistance. It was confirmed that by adding PDMS into PS, the resistance to the dry etch dramatically increased, but the sensitivity and contrast remained nearly the same. Thus, PS-PDMS can be a low-cost replacement of HSQ resist when negative tone e-beam resist with high dry etch resistance is required

Validation of radiative transfer computation with Monte Carlo method for ultra-relativistic background flow

We developed a three-dimensional radiative transfer code for an ultra-relativistic background flow-field by using the Monte Carlo (MC) method in the context of gamma-ray burst (GRB) emission. For obtaining reliable simulation results in the coupled computation of MC radiation transport with relativistic hydrodynamics which can reproduce GRB emission, we validated radiative transfer computation in the ultra-relativistic regime and assessed the appropriate simulation conditions. The radiative transfer code was validated through two test calculations: (1) computing in different inertial frames and (2) computing in flow-fields with discontinuous and smeared shock fronts. The simulation results of the angular distribution and spectrum were compared among three different inertial frames and in good agreement with each other. If the time duration for updating the flow-field was sufficiently small to resolve a mean free path of a photon into ten steps, the results were thoroughly converged. The spectrum computed in the flow-field with a discontinuous shock front obeyed a power-law in frequency whose index was positive in the range from 1 to 10 MeV. The number of photons in the high-energy side decreased with the smeared shock front because the photons were less scattered immediately behind the shock wave due to the small electron number density. The large optical depth near the shock front was needed for obtaining high-energy photons through bulk Compton scattering. Even one-dimensional structure of the shock wave could affect the results of radiation transport computation. Although we examined the effect of the shock structure on the emitted spectrum with a large number of cells, it is hard to employ so many computational cells per dimension in multi-dimensional simulations. Therefore, a further investigation with a smaller number of cells is required for obtaining realistic high-energy photons with multi-dimensional computations

子宮内膜症と関連する卵巣癌 : 明細胞腺癌と類内膜腺癌の発癌機序における相違点

The histogenesis of endometriosis and endometriosis-associated ovarian cancer is one of the most mysterious aspects of pathology. To better understand the histogenesis of endometriosis and endometriosis-associated ovarian cancer, we analyzed the possibility of a link of endometrium, ovarian surface epithelium, and a cortical inclusion cyst to ovarian endometriosis and endometriosis-associated ovarian cancer by immunohistochemistry using the epithelial membrane antigen (an epithelial marker), calretinin (a mesothelial marker), and hepatocyte nuclear factor (HNF)-1β (a clear cell carcinoma-specific transcription factor). During ovarian surface epithelium invagination, cortical inclusion cyst epithelial cells may, in some cases, undergo mesothelial–epithelial transition and subsequently differentiate into endometriosis. This case of endometriosis that has undergone Müllerian metaplasia arises from the HNF-1β-negative cells. The remaining endometriosis may develop from the late secretory and menstrual endometria, with HNF-1β-positive staining, by retrograde menstruation. Endometrioid adenocarcinoma and clear cell carcinoma arise from the HNF-1β-negative and HNF-1β-positive epithelial cells of endometriosis, respectively. It has been proposed that clear cell and endometrioid-type adenocarcinomas arise from distinct types of endometriosis with different cells of origin.博士（医学）・乙第1309号・平成25年3月15日©2012 International Society of Gynecological Pathologist

Response to "Comment on `Quantum-confinement effects on the optical and dielectric properties for mesocrystals of BaTiO3 and SrBi2Ta2O9\u27"

In this reply, the authors show that the argument by Scott regarding the band gap of bulk SrBi2Ta2O9 (SBT) is not based on concrete evidence. The authors will also show additional data from a Raman study of a powdered SBT sample to prove that the surface of the specimen was not covered by Bi2O3

Response to "Comment on `Quantum-confinement effects on the optical and dielectric properties for mesocrystals of BaTiO3 and SrBi2Ta2O9

In this reply, the authors show that the argument by Scott regarding the band gap of bulk SrBi2Ta2O9 (SBT) is not based on concrete evidence. The authors will also show additional data from a Raman study of a powdered SBT sample to prove that the surface of the specimen was not covered by Bi2O3