565 research outputs found
Threshold photoelectron photoion coincidence spectroscopy and selected ion flow tube reactions of CHF3: comparison of product branching ratios
The threshold photoelectron and threshold photoelectron photoion coincidence spectra of CHF in the range 13.5 – 24.5 eV have been recorded. Ion yields and branching ratios have been determined for the three fragments CF, CHF2 and CF. The mean kinetic energy releases into fragment ions involving either C-H or C-F bond cleavage have been measured, and compared with statistical and impulsive models. CHF behaves in a non-statistical manner characteristic of the small-molecule limit, with the ground electronic state and low-lying excited states of CHF being largely repulsive along the C-H and C-F coordinates, respectively. The rate coefficients and product ion branching ratios have been measured at 298 K in a selected ion flow tube for the reactions of CHF with a large number of gas-phase cations whose recombination energies span the range 6.3 through 21.6 eV. A comparison between the branching ratios from the two experiments, together with an analysis of the threshold photoelectron spectrum of CHF, shows that long-range charge transfer probably occurs for the Ar and F atomic ions whose recombination energies lie above ca. 15 eV. Below this energy, the mechanism involves a combination of short-range charge transfer and chemical reactions involving a transition state intermediate
Edge Critical Behaviour of the 2-Dimensional Tri-critical Ising Model
Using previous results from boundary conformal field theory and
integrability, a phase diagram is derived for the 2 dimensional Ising model at
its bulk tri-critical point as a function of boundary magnetic field and
boundary spin-coupling constant. A boundary tri-critical point separates phases
where the spins on the boundary are ordered or disordered. In the latter range
of coupling constant, there is a non-zero critical field where the
magnetization is singular. In the former range, as the temperature is lowered,
the boundary undergoes a first order transition while the bulk simultaneously
undergoes a second order transition.Comment: 6 pages, RevTex, 3 postscript figure
Excited Boundary TBA in the Tricritical Ising Model
By considering the continuum scaling limit of the RSOS lattice model
of Andrews-Baxter-Forrester with integrable boundaries, we derive excited state
TBA equations describing the boundary flows of the tricritical Ising model.
Fixing the bulk weights to their critical values, the integrable boundary
weights admit a parameter which plays the role of the perturbing
boundary field and induces the renormalization group flow between
boundary fixed points. The boundary TBA equations determining the RG flows are
derived in the example. The
induced map between distinct Virasoro characters of the theory are specified in
terms of distribution of zeros of the double row transfer matrix.Comment: Latex, 14 pages - Talk given at the Landau meeting "CFT and
Integrable Models", Sept. 2002 - v2: some statements about
perturbations correcte
Highly ordered CdS nanoparticle arrays on silicon substrates and photoluminescence properties
Highly ordered cadmium sulphide (CdS) nanoparticle (NP) arrays were fabricated on silicon (Si) substrates using ultrathin alumina membranes as evaporation masks. The CdS NPs are polycrystalline and are composed of ultrasmall closely packed nanocrystallites. These crystallites increase in size as the duration of the CdS evaporation process increases. When the thickness of the NPs changes from about 10 to 50 nm, the size of the crystallites increases from about 5–14 to 20–40 nm. Photoluminescence measurements on the CdS NP arrays show a strong emission spectrum with two subbands that are attributed to band-edge and surface-defect emissions. The peak position and width of the band-edge emission band are closely related to the size of the crystallites in the CdS NPs.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87842/2/103106_1.pd
Atypical burkitt's lymphoma transforming from follicular lymphoma
Amongst follicular lymphoma that transforms into a high-grade lymphoma, majority are diffuse large B cell lymphoma. Here we reported a rare atypical Burkitt's lymphoma transformation from an asymptomatic follicular lymphoma. Lymph node biopsy showed a composite lymphoma with infiltration of the inter-follicular areas by high grade small non-cleaved lymphoma cells amongst neoplastic follicles. Moreover, FISH and molecular genetic study confirmed concomitant MYC translocations and t(14;18) in the high-grade component, thereby suggesting the transformation of atypical Burkitt's lymphoma from an undiagnosed antecedent follicular lymphoma. The disease followed an aggressive clinical course, terminating in refractory disease 13 months after diagnosis. This is followed by a comprehensive review of the literature on lymphoma transformations from underlying follicular lymphoma after acquisition of MYC translocation, using Burkitt's lymphoma, follicular lymphoma, transformation and MYC translocations as keywords
On the Integrable Structure of the Ising Model
Starting from the lattice realization of the Ising model defined on a
strip with integrable boundary conditions, the exact spectrum (including
excited states) of all the local integrals of motion is derived in the
continuum limit by means of TBA techniques. It is also possible to follow the
massive flow of this spectrum between the UV conformal fixed point and
the massive IR theory. The UV expression of the eigenstates of such integrals
of motion in terms of Virasoro modes is found to have only rational
coefficients and their fermionic representation turns out to be simply related
to the quantum numbers describing the spectrum.Comment: 18 pages, no figure
A Simple and Efficient Way to Combine Microcontrollers with RSA Cryptography
Microcontroller can be easily adopted in various applications with a variety of peripherals due to its merits of small size, simple architecture and etc. However, the limited computing power restricts its application in cryptography. In this paper, we try to integrate microcontroller with different peripheral devices to support more powerful cryptography computation in a simple and efficient way. Based on the most popular open source microcontroller development platform, Arduino, we design and develop a cryptographic hardware device for a real-life application which provides data protection functions for authority and integrity with RSA cryptography supported. With the peripherals Java card, our Arduino-cored solution is able to efficiently generate digital signature of photos taken by smart phone using the asymmetric cryptographic algorithm, RSA, which has a poor performance if it is directly implemented on microcontroller. The experimental results show that the device can finish a RSA 1024-bit encryption in 82.2 microseconds, which is reasonable in real application scenario and illustrates the feasibility of implementing more complicated cryptographic system using microcontroller.published_or_final_versio
Consistent superconformal boundary states
We propose a supersymmetric generalization of Cardy's equation for consistent
N=1 superconformal boundary states. We solve this equation for the
superconformal minimal models SM(p/p+2) with p odd, and thereby provide a
classification of the possible superconformal boundary conditions. In addition
to the Neveu-Schwarz (NS) and Ramond (R) boundary states, there are NS~ states.
The NS and NS~ boundary states are related by a Z_2 "spin-reversal"
transformation. We treat the tricritical Ising model as an example, and in an
appendix we discuss the (non-superconformal) case of the Ising model.Comment: 23 pages, LaTeX; amssymb, epsf, 1 eps figure; v2: references adde
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