Heat propagation and stability in a small high Tc superconductor coil

Using a Bi-based small high T_c superconductor (HTSC) coil, we have studied its stability against a local disturbance and current-induced quench in the helium gas cooling condition. While the stability margin of HTSC coil against a local disturbance was very large, quench current was limited by a catastrophic temperature rise which originated from the nonlinear characteristic of the Joule heating. The crucial parameter for the quench becomes the nonlinear resistance in HTSC as a function of temperature and transport current. It has been shown that the dynamic characteristics of the quench can be described quantitatively by the simplified one-dimensional heat balance equation.     

Kinetics for the reaction of methine proton of an unsymmetrical tetradentate Schiff base complex of nickel(II) with N-chlorosuccinimide

The substitution reaction of the methine proton of an unsymmetrical tetradentate Schiff base complex of nickel(II) with N-chlorosuccinimide was kinetically studied in a dichloromethane solution. While the rate of chlorination was decreased by the addition of acetone or ether, the rate was significantly increased by the addition of ethanol. The rate of bromination was faster than that of chlorination. A four-centred intermediate was proposed for the halogenation reaction of the Schiff base nickel(II) complex.     

Reflection K-matrices of the 19-vertex model and XXZ spin-1 chain with general boundary terms

We derive and classify all solutions of the boundary Yang-Baxter equation (or the reflection equation) for the 19-vertex model associated with . An integrable XXZ spin-1 chain Hamiltonian with general boundary interactions is also obtained.     

Efficient intramolecular Diels–Alder reactions of ester-tethered 1,7,9-decatrienoates catalyzed by bis-aluminated trifluoromethanesulfonamide

Bis-aluminated trifluoromethanesulfonamide generated in situ by mixing TfNH₂ (1 mol) and methylaluminum reagent (2 mol) is an effective catalyst for the IMDA reaction of ester-tethered 1,7,9-decatrienoates.     

Atomic structure of boron nitride nanotubes with an armchair-type structure studied by HREM

Hexagonal networks of boron nitride (BN) nanotubes were investigated by high-resolution electron microscopy (HREM) and image simulation. From HREM images, lattice planes of {002} and hexagonal rings of a BN nanotube were confirmed. Asymmetrical layer arrangements were found, and a structure model for double-walled BN nanotube with an armchair-type structure has been proposed.     

Correlated isocurvature fluctuation in quintessence and suppressed cosmic microwave background anisotropies at low multipoles

We consider cosmic microwave background (CMB) anisotropy in models with quintessence, taking into account isocurvature fluctuation. It is shown that, if the primordial fluctuation of the quintessence has a correlation with the adiabatic density fluctuations, the CMB angular power spectrum C(l) at low multipoles can be suppressed without affecting C(l) at high multipoles. A possible scenario for generating a correlated mixture of the quintessence and adiabatic fluctuations is also discussed.     

Recent progress in plant cell culture

Conclusions Commercial application of plant cell cultures for the production of useful metabolites on a large scale has not yet been realized. However, some recently published papers and patents seem very attractive for industrial use because their results and techniques are apparently applicable to a large-scale production of metabolites. The author believes that commercial success using plant tissue cultures will be realized in the near future with advanced techniques if product selection is determined by economic and political principles. In 1982, the 5th International Congress of Plant Tissue and Cell Culture will be held in Japan and this undoubtedly will encourage research activity in our country.     

Renormalization group estimate of the hadronic decay width of the Higgs boson

The total hadronic decay width of the Weinberg-Salam type Higgs boson is estimated in QCD for the Higgs boson mass much larger than the ordinary hadronic mass scale, by use of the operator product expansion and renormalization group equation. We give an explicit formula for the decay width in terms of quark masses including strong interaction corrections up to the next-to-leading order. A numerical analysis of the hadronic decay width of the Higgs boson is made in the six-quark model. The next-to-leading order correction is found to be significant, e.g., 30-20% of the leading term for m_H of oue interest, m_H ? 1 TeV. Application of our scheme to the decay rates of heavy Higgs bosons of other types is also discussed.     

Synthesis of a novel C-6 nigrogen-substituted carbapenem from 6-aminopenicillanic acid

Synthesis of optically active 6-phthalimidocarbapenems from 6-aminopenicillanic acid is described.     

Finite element analysis of creeping flows using marker particles

The penalty function formulation of the finite element method is described for the analysis of transient incompressible creeping flows. Marker particles are utilized to represent moving free surfaces and to visualize the flow patterns. For determining the movement of markers from element to element, the area coordinate system of the linear triangular element is introduced. With the method presented, a punch indentation problem and an injection problem for an L-shaped cavity are solved for Newtonian and power-law fluids.