Two-dimensional higher-derivative supergravity and a new mechanism for supersymmetry breaking

We discuss the general form of quadratic (1,1) supergravity in two dimensions, and show that this theory is equivalent to two scalar supermultiplets coupled to nontrivial supergravity. It is demonstrated that the theory possesses stable vacua with vanishing cosmological constant which spontaneously break supersymmetry.     

Prediction of liquid viscosities of phosphorus-containing compounds by Souders' method

Souders' method of predicting the viscosities of liquid compounds from structural information has been extended to include the contribution from the phosphorus atom. The phosphorus contribution has been predicted from the critical pressure to be 67.1. The prediction method has been tested using data available on 15 phosphorus-containing compounds. The results are comparable with those reported in the literature for group contribution methods in general.     

Strategy for deciding between the use of single or biphasic systems as media for biocatalytic transformations using chemical equilibrium analysis

A theoretical model is derived to decide whether biphasic systems or single-phase aqueous systems are chosen as the media for microbial transformations. The yield ratio and product ratio at chemical equilibrium, which depend on the partition coefficients, equilibrium constants, activity coefficients and initial concentrations, are proposed as appropriate indices by the analysis of four common types of biochemical reaction under two extreme initial conditions.     

Asymmetric Host Molecule Bearing Pyridine Core for Highly Efficient Blue Thermally Activated Delayed Fluorescence OLEDs

In this study, two host materials, pCzBzbCz and pCzPybCz , are synthesized to achieve a high efficiency and long lifetime of blue thermally activated delayed fluorescence organic light-emitting diodes (TADF-OLEDs). The molecular design strategy involves the introduction of a pyridine group into the core structure of pCzPybCz as an electron-withdrawing unit, and an electron-donating phenyl group into the structure of pCzBzbCz . These host materials demonstrate good thermal stability and high triplet energy (T₁=3.07 eV for pCzBzbCz and 3.06 eV for pCzPybCz ) for the fabrication of blue TADF-OLEDs. In particular, pCzPybCz -based OLED devices demonstrate an external quantum efficiency (EQE) of 22.7 % and an operational lifetime of 24 h (LT₉₀, time to attain 90 % of initial luminance) at an initial luminance of 1000 cd m⁻². This superior lifetime could be explained by the C−N bond dissociation energy (BDE) in the host molecular structure. Furthermore, a mixed-host system using the electron-deficient 2,4-bis(dibenzo[b,d]furan-2-yl)-6-phenyl-1,3,5-triazine (DDBFT) is proposed to inhibit the formation of the anion state of our host materials. In short, the device operational lifetime is further improved by applying DDBFT. The carbazole-based asymmetric host molecule containing a pyridine core realizes a high-efficiency blue TADF-OLED showing a positive effect on the operating lifetime, and can provide useful strategies for designing new host materials.     

Quest for precision in hadronic cross sections at low energy: Monte Carlo tools vs. experimental data

We present the achievements of the last years of the experimental and theoretical groups working on hadronic cross section measurements at the low-energy e ⁺ e ^? colliders in Beijing, Frascati, Ithaca, Novosibirsk, Stanford and Tsukuba and on τ decays. We sketch the prospects in these fields for the years to come. We emphasise the status and the precision of the Monte Carlo generators used to analyse the hadronic cross section measurements obtained as well with energy scans as with radiative return, to determine luminosities and τ decays. The radiative corrections fully or approximately implemented in the various codes and the contribution of the vacuum polarisation are discussed.     

A Simple Method for the Preparation of Substituted Phenoxyacrylic Acid Phenyl Esters

A simple and efficient synthesis of phenoxyacrylic acid phenyl esters via one pot esterification and Michael-type addition starting from propynoic acid and an excess of an appropriate phenol is described.     

From the LHC to future colliders

Discoveries at the LHC will soon set the physics agenda for future colliders. This report of a CERN Theory Institute includes the summaries of Working Groups that reviewed the physics goals and prospects of LHC running with 10 to 300 fb^?1 of integrated luminosity, of the proposed sLHC luminosity upgrade, of the ILC, of CLIC, of the LHeC and of a muon collider. The four Working Groups considered possible scenarios for the first 10 fb^?1 of data at the LHC in which (i) a state with properties that are compatible with a Higgs boson is discovered, (ii) no such state is discovered either because the Higgs properties are such that it is difficult to detect or because no Higgs boson exists, (iii) a missing-energy signal beyond the Standard Model is discovered as in some supersymmetric models, and (iv) some other exotic signature of new physics is discovered. In the contexts of these scenarios, the Working Groups reviewed the capabilities of the future colliders to study in more detail whatever new physics may be discovered by the LHC. Their reports provide the particle physics community with some tools for reviewing the scientific priorities for future colliders after the LHC produces its first harvest of new physics from multi-TeV collisions.