Radiative recombination of excitons in disk-shaped InAs/InP quantum dots

Recombination dynamics of excitons confined in disk-shaped InAs/InP quantum dots is studied by time-resolved photoluminescence measurements. By comparing the result with that in a homologous ultrathin quantum well, it is revealed that the lateral confinement of excitons suppresses the thermal variation of the radiative recombination lifetime. The oscillator strength of the radiative transition is reduced with the decrease of the disk height, which is attributed to the increasing tunneling into the InP barrier of the exciton wave function

Double-Network Hydrogels Strongly Bondable to Bones by Spontaneous Osteogenesis Penetration

Implanting hydroxyapatite-mineralized tough hydrogel into osteochondral defects of rabbits, osteogenesis spontaneously penetrates into the gel matrix owing to the semi-permeablility of the hydrogel. The gradient layer (around 40 μm thick) contributes quite strong bonding of the gel to bone. This is the first success in realizing the robust osteointegration of tough hydrogels, and the method is simple and feasible for practical use

System-logical Considerations on the Optimum Retention Period of Stands in the Forest Management

The key task for forest planner is it describe the expected production potentials of forest, and to allocate the forest area to produce the timbers and services that are wanted. One of the most important decision that a forest owner must make is to determine whether a forest stand should be cut or reserved or when it should be cut in accordance with the estimation of its financial maturity period with the maximization of the total net present value of the whole forestry stand. This paper aims to describe an approach for timber harvest scheduling and optimization of forest stands retention period. The method is based on the combined use of a network planning system and a linear programming that generates treatments schedules for forest stands and selects optimal schedule combination. The forest planning system consists of two principal parts: optimization and simulation. In the simulation the future development of stands is predicted and a large number of possible treatments schedules are generated for each stands. The simulation also produces information on the results attained if the treatment schedule is applied. Optimization method is used to select one treatment if the treatment for stands from the simulated schedule. This model can therefore furnish more effective information on the long term forest management decision making of forest owners