Scaling of the specific heat in superfluid films

We study the specific heat of the $x-y$ model on lattices $L \times L \times H$ with $L \gg H$ (i.e. on lattices representing a film geometry) using the Cluster Monte--Carlo method. In the $H$--direction we apply Dirichlet boundary conditions so that the order parameter in the top and bottom layers is zero. We find that our results for the specific heat of various thickness size $H$ collapse on the same universal scaling function. The extracted scaling function of the specific heat is in good agreement with the experimentally determined universal scaling function using no free parameters.Comment: 4 pages, uuencoded compressed PostScrip

Literatur-Rundschau

Eckard Bieger: Das Öffentlichkeitsdilemma der katholischen Kirche (Michael Schmolke)Johanna Haberer: Gottes Korrespondenten. Geistliche Rede in der Mediengesellschaft (Rüdiger Funiok)Gernot Brauer: Presse- und Öffentlichkeitsarbeit. Ein Handbuch (Roland Burkart)Ralf Laumer (Hg.): Bücher kommunizieren. Das PR-Arbeitsbuch für Bibliotheken, Buchhandlungen und Verlage (Steffen W. Hillebrecht)Wemer Faulstich: Die bürgerliche Mediengesellschaft (1700-1830) und: Medienwandel im Industrie- und Massenzeitalter (1830-1900) (Michael Schmolke)

Literatur-Rundschau

Harald Pawlowski: Die Zukunft liegt in jedem Augenblick (Michael Schmolke)Ron Brinitzer: Religion - eine institutionenökonomische Analyse (Steffen W. Hillebrecht)Willern Marie Speelmann: Liturgie in beeld: Over de identiteit van de rooms-katholieke liturgie in de elektronische media (Martin Gertler)Mirko Marr: Internetzugang und politische Informiertheit (Michael Harnischmacher)Peter Overbeck (Hg.): Musikjournalismus (Liane Rothenberger)Martin Sabrow/Ralph Jessen/Klaus Große Kracht (Hg.): Zeitgeschichte als Streitgeschichte (Michael Schmolke)Inge Kloepfer: Friede Springer (Ute Stenert)

Scaling of thermal conductivity of helium confined in pores

We have studied the thermal conductivity of confined superfluids on a bar-like geometry. We use the planar magnet lattice model on a lattice $H\times H\times L$ with $L \gg H$. We have applied open boundary conditions on the bar sides (the confined directions of length $H$) and periodic along the long direction. We have adopted a hybrid Monte Carlo algorithm to efficiently deal with the critical slowing down and in order to solve the dynamical equations of motion we use a discretization technique which introduces errors only $O((\delta t)^6)$ in the time step $\delta t$. Our results demonstrate the validity of scaling using known values of the critical exponents and we obtained the scaling function of the thermal resistivity. We find that our results for the thermal resistivity scaling function are in very good agreement with the available experimental results for pores using the tempComment: 5 two-column pages, 3 figures, Revtex

Perturbative calculation of the scaled factorial moments in second-order quark-hadron phase transition within the Ginzburg-Landau description

The scaled factorial moments $F_q$ are studied for a second-order quark-hadron phase transition within the Ginzburg-Landau description. The role played by the ground state of the system under low temperature is emphasized. After a local shift of the order parameter the fluctuations are around the ground state, and a perturbative calculation for $F_q$ can be carried out. Power scaling between $F_q$'s is shown, and a universal scaling exponent $\nu\simeq 1.75$ is given for the case with weak correlations and weak self-interactions.Comment: 12 pages in RevTeX, 12 eps figure

The specific heat of thin films near the lambda-transition: A Monte Carlo study of an improved three-dimensional lattice model

We study the finite size scaling behaviour of the specific heat of thin films in the neighbourhood of the lambda-transition. To this end we have simulated the improved two-component phi^4 model on the simple cubic lattice. We employ free boundary conditions in the short direction to mimic the vanishing order parameter at the boundaries of a 4He film. Most of our simulations are performed for the thicknesses L_0=8,16 and 32 of the film. It turns out that one has to take into account corrections proportional 1/L_0 to obtain a good collapse of the finite size scaling functions obtained from different L_0. Our results are compared with those obtained from experiments on thin films of 4He near the lambda-transition, from field theory and from previous Monte Carlo simulations.Comment: 46 pages, 15 figure

The specific heat of superfluids near the transition temperature

The specific heat of the $x-y$ model is studied on cubic lattices of sizes $L \times L \times L$ and on lattices $L \times L \times H$ with $L \gg H$ (i.e. on lattices representing a film geometry) using the Cluster Monte Carlo method. Periodic boundary conditions were applied in all directions. In the cubic case we obtained the ratio of the critical exponents $\alpha/\nu$ from the size dependence of the energy density at the critical temperature $T_{\lambda}$. Using finite--size scaling theory, we find that while for both geometries our results scale to universal functions, these functions differ for the different geometries. We compare our findings to experimental results and results of renormalization group calculations.Comment: self-unpacking uuencoded PostScript file (for instructions see the beginning of the file), 18 pages

DNA immunization as a technology platform for monoclonal antibody induction

To combat the threat of many emerging infectious diseases, DNA immunization offers a unique and powerful approach to the production of high-quality monoclonal antibodies (mAbs) against various pathogens. Compared with traditional protein-based immunization approaches, DNA immunization is efficient for testing novel immunogen designs, does not require the production or purification of proteins from a pathogen or the use of recombinant protein technology and is effective at generating mAbs against conformation-sensitive targets. Although significant progress in the use of DNA immunization to generate mAbs has been made over the last two decades, the literature does not contain an updated summary of this experience. The current review provides a comprehensive analysis of the literature, including our own work, describing the use of DNA immunization to produce highly functional mAbs, in particular, those against emerging infectious diseases. Critical factors such as immunogen design, delivery approach, immunization schedule, use of immune modulators and the role of final boost immunization are discussed in detail

Li14Ln5[Si11N19O5]O2F2 with Ln = Ce, Nd-Representatives of a Family of Potential Lithium Ion Conductors

The isotypic layered oxonitridosilicates Li14Ln5[Si11N19O5]O2F2 (Ln = Ce, Nd) have been synthesized using Li as fluxing agent and crystallize in the orthorhombic space group Pmmn (Z = 2, Li14Ce5[Si11N19O5]O2F2: a = 17.178(3), b = 7.6500(15), c = 10.116(2) Å, R1 = 0.0409, wR2 = 0.0896; Li14Nd5 Si11N19O5]O2F2: a = 17.126(2), b = 7.6155 15), c = 10.123(2) Å, R1 = 0.0419, wR2 = 0.0929). The silicate layers consist of dreier and sechser rings interconnected via common corners, yielding an unprecedented silicate substructure. A topostructural analysis indicates possible 1D ion migration pathways between five crystallographic independent Li positions. The specific Li-ionic conductivity and its temperature dependence were determined by impedance spectroscopy as well as DC polarization/depolarization measurements. The ionic conductivity is on the order of 5 × 10−5 S/cm at 300°C, while the activation energy is 0.69 eV. Further adjustments of the defect chemistry (e.g., through doping)can make these compounds interesting candidates for novel oxonitridosilicate based ion conductors