An intense terahertz radiation source at the Compact ERL

The Compact ERL is an energy recovery LINAC (ERL) test facility that is planned for KEK. The circumference of the recirculation path will be 70 m. Initially, the beam energy will be about 65 MeV and the current about 10 mA. Although the primary purpose of the machine is to aid the development of the key technologies that are essential for building an ultra-brilliant new synchrotron light source based on an ERL, the Compact ERL itself has great potential as an intense source of terahertz radiation. To generate the intense terahertz radiation, an electron bunch of a very short bunch length is required and bunch compression is inevitable. We discuss the parameters of the Compact ERL, present the results of a simulation of bunch compression, and make an estimate of the generated coherent synchrotron radiation.     

Detection of multiple anions by thin-layer chromatography

A novel detection method for 21 different anions by thin-layer chromatography is presented. Anions on the target plate form salts with amine in a developing solvent and are visualized after staining with citric acid-acetic anhydride reagent as white spots contrasting against a pale red-pink background. This method has particularly high sensitivity for anions of chlorate, sulfate, phosphate, chromate and dichromate (0.02-0.05 microg). The method is demonstrated to efficiently detect toxic arsenite in curry sauce as an example application. The proposed method offers highly efficient indirect detection for a wide range of anions, and serves as a purification procedure for the preparation of anionic sample solutions for other analytical methods.     

BF3.OEt2-mediated cycloaddition of O-tert-butyldimethylsilyloximes having olefin moieties: intramolecular cycloaddition of N-borano-nitrones

Treatment of O-tert-butyldimethylsilyloximes having olefin moieties in the molecules with BF3.OEt2 results in efficient generation of N-borano-nitrones, which undergo intramolecular cycloaddition at room temperature to afford N-nonsubstituted cycloadducts after work-up.     

Practical carbonyl-ene reactions of alpha-methylstyrenes with paraformaldehyde promoted by a combined system of boron trifluoride and molecular sieves 4A

[reaction: see text] A combined system of boron trifluoride and molecular sieves is an efficient promoter for the carbonyl-ene reaction of alpha-methylsyrenes with paraformaldehyde. The coexistence of BF3 x OEt2 and molecular sieves 4A is essential for obtaining high yields of ene products.     

Control of light pulse propagation with only a few cold atoms in a high-finesse microcavity

Propagation of a light pulse through a high-Q optical microcavity containing a few cold atoms (N<10) in its cavity mode is investigated experimentally. With less than ten cold rubidium atoms launched into an optical microcavity, up to 170 ns propagation lead time ("superluminal"), and 440 ns propagation delay time (subluminal) are observed. Comparison of the experimental data with numerical simulations as well as future experiments are discussed.     

Observation of D+(s)K- and evidence for D+(s)pi- final states in neutral B decays

We report the first observation of a B meson decay that is not accessible by a direct spectator process. The channel B(0)-->D(+)(s)K- is found in a sample of 85 x 10(6) BB; events, collected with the Belle detector at KEKB, with a branching fraction B(B(0)-->D(+)(s)K-)=(4.6(+1.2)(-1.1)+/-1.3) x 10(-5). We also obtain evidence for the B0-->D(+)(s)pi(-) decay with branching fraction B(B0-->D(+)(s)pi(-))=(2.4(+1.0)(-0.8)+/-0.7) x 10(-5). This value may be used to extract a model-dependent value of |V(ub)|.     

Multiple reflections of Lamb waves at a delamination

Wave propagation in laminated plates with delaminations was calculated using the semi-analytical finite element method. The visualization results and deeper numerical analyses revealed the following phenomena on the fundamental Lamb modes at delamination regions of laminated plates. First, Lamb wave propagates toward the delamination, and then splits into two independent waves at the "Entrance" of the delamination with no significant reflections. These two waves reach the "Exit" of the delamination with the different phases and arrival time. Thus reflected and transmitted waves are excited at the Exit. The repetition of such reflections at the Exit causes the multiple reflections at regular intervals corresponding to the delamination size.