We present investigation of a single nitrogen-vacancy (NV) center in diamond and couplings to surrounding electron
spins. Using double electron-electron resonance spectroscopy, we demonstrate magnetic resonance (MR) spectroscopy
of nitrogen electron spins surrounding a single NV center in diamond. In addition, we discuss development of a MR
system to investigate NV centers at high magnetic fields.
Modulators using silicon waveguides with a small (~100 nm) slot in the center of the waveguide filled with an electro-optic
polymer can have very low switching voltage. A variety of challenges, including difficulty poling the polymer and
difficulty achieving high-speed operation, have so far prevented successful demonstration. Problems poling the polymer
may be electrical, such as nonuniform poling fields or too much polymer conductivity compared to the silicon
electrodes, or they may be more fundamental. This paper discusses research into one possible improvement in the
polymer poling method, which is illumination of the device with an 800-nm-wavelength laser during poling to improve
conductivity between the external voltage source and the polymer in the slot.
In this study, the dynamic fracture behavior of a bonded dissimilar material, which had the interfacial crack, was analyzed. The stress intensity factor of the interfacial crack was determined by using method of caustics and the simple type high-speed photography method for the analysis, and dynamic behavior of the interfacial crack, which received the shearing deformation, was observed. The test specimen shape was assumed to be ENF test specimen. The sample material made to epoxy resin and polycarbonate, and used an epoxy system adhesive for joining. As a result, the vibration characteristic was possessed in the interfacial crack as well as the crack in a homogeneous material. And, a dynamic fracture toughness of the interfacial crack reached a different value by a material and joined condition to receive the load. Moreover, the propagation behavior of the interfacial crack became a different result with receiving the load and the phase material. The interfacial crack wound to the upper phase material at the case when the upper phase material was a brittleness material, and the propagating angle of the crack was 70 degrees. The dynamic fracture behavior of the interfacial crack when the upper phase material was ductile material propagated on the interface at high speed. In addition, the time of the propagation of the crack became a result different depending on joined condition, too. When the upper phase material was brittle material, the crack propagation time became a slow result early for ductile materials. The dynamic fracture toughness value and the crack propagation time of the interfacial crack became different results by the difference of the component of the test specimen. Therefore, dynamic fracture toughness and the crack propagating behavior depended on a material and joined condition to receive the load.
It is very important to understand a dynamic fracture behavior under the high temperature environment. However, these researches of polymeric materials is unexpectedly little. In this study, the cracked polycarbonate plate was used for a sample material, and carry out the impact three point bending test in the electric furnace. The caustics method and the simple high-speed photography method was used for the analysis. As experimental results. A different fracture behavior was shown whether by doing the dehydration processing same normal temperature (23.5 degrees Celsius). At the higher temperature, the dynamic stress intensity factor indicated lower value. In addition, it has been understood that there is a tendency to which the fracture toughness value decreases while becoming a high temperature.
The orthotropic material which has been developed by authors using copper wires as fiber and epoxy resin as base material is necessary to know optical constants to determine a stress intensity factor by experiments. As a result, it was found that, by applying caustics theory, optical constants could quite easily be obtained in either case of experiments conducted with the specimen held in the air, immersed in liquid, or at the state of frozen stress.