Abstract: An illumination device having a reflecting plate, at least one linear light source arranged on a first side of the reflecting plate, a diffusing plate arranged on a second side of the reflecting plate, and a light quantity adjusting member formed integrally with the reflecting plate.

Abstract: An illumination device comprising a reflecting plate, a single or a plural number of linear light source(s) arranged over said reflecting plate and a diffusing plate arranged over said light source(s), a light quantity adjusting means being arranged on the surface of the linear light source on between said light source(s) and said diffusing plate, and said illumination device being so adapted as to uniformalize luminance distribution on the diffusing plate by selecting shape and size of light-transmitting portions of the light quantity adjusting means.

Abstract: An illumination device comprising a reflecting plate, a single or a plural number of linear light source(s) arranged over said reflecting plate and a diffusing plate arranged over said light source(s), a light quantity adjusting means being arranged on the surface of the linear light source on between said light source(s) and said diffusing plate, and said illumination device being so adapted as to uniformalize luminance distribution on the diffusing plate by selecting shape and size of light-transmitting portions of the light quantity adjusting means.

Abstract: A hole-burning material which comprises at least one hole which is formed on a zero-phonone line and semi-permanently lasts without suffering from any change in the temperature range from 2 to 120 K. and which can be erased by irradiation of excited light having an energy larger than the zero-phonone line, in which the burnt holes have long life and deep depth and any single holes can be erased.

Abstract: A green diamond has a nitrogen content in its crystals within the range of 5.times.10.sup.16 to 3.times.10.sup.19 atoms/cm.sup.3, an absorption coefficient of H2 centers at a wavelength of 800 nm within the range of 0.3 to 6 cm.sup.-1, an absorption coefficient of the Ib type nitrogen at a wavelength of 500 nm within the range of 0.05 to 1.5 cm.sup.-1, and absorption coefficients of H3 centers, H4 centers, N-V centers and GR1 centers in the visible region of not more than 0.2 cm.sup.-1. Such green diamonds are produced by preparing a clear-yellow Ib type diamond having a nitrogen content in crystals within the range of 5.times.10.sup.16 to 3.times.10.sup.19 atoms/cm.sup.3, irradiating this diamond with an electron beam having not less than 1.times.10.sup.18 electrons/cm.sup.2 at an accelerating voltage of 2 to 4 MeV, and subjecting the diamond to a heat treatment at a temperature of 1500.degree. C.-1800.degree. C. in a vacuum of not more than 10.sup.-3 torr.

Abstract: A method of manufacturing a diamond laser crystal having an excellent laser efficiency is performed by first, preparing a synthetic type Ib diamond containing at least 60 volume percent of a (111) plane growth sector (43) is prepared. This synthetic diamond is then thermally treated under high temperature/high pressure, so that type Ib nitrogen contained in the synthetic diamond is converted to type IaA nitrogen. Thereafter an electron beam is applied to the synthetic diamond in order to generate vacancies in the synthetic diamond. Finally annealing is performed on the synthetic diamond to form H3 centers by coupling the type IaA nitrogen atoms contained in the synthetic diamond, with the vacancies. According to this method, the H3 centers can be formed in the synthetic type Ib diamond at high concentration, while formation of NV centers which become an obstacle to laser action, can be suppressed.

Abstract: A purple diamond has an absorption coefficient of the Ib type nitrogen at 500 nm, within the range of 0.2-2 cm.sup.-1, an absorption coefficient of the N-V center at an absorption peak of 570 nm, within the range of 0.3-10 cm.sup.-1, and absorption coefficients of the GR1 center, H2 center, H3 center, and H4 center which are less than 0.2 cm.sup.-1 in the visible region. A method of producing such a purple diamond uses as a starting material an Ib type artificial synthetic diamond crystal wherein the Ib type nitrogen content in the crystal is within the range of 8.times.10.sup.17 -1.4.times.10.sup.19 atoms/cm.sup.3, such a starting material is subjected to an electron beam irradiation of 5.times.10.sup.16 -2.times.10.sup.18 electrons/cm.sup.2 at 2-4 MeV, and then annealing the irradiated diamond in a vacuum of less than 10.sup.-2 Torr, at a temperature of 800.degree.-1100.degree. C. for more than 25 hours.

Abstract: A diamond laser formed of a synthetic diamond provides a high output power and a variable wavelength in the near infrared region. The maximum value of the optical density of H2 centers in the direction of the pumping light is in the range of 0.01 to 4. Laser action is caused in the range of 1000 to 1400 nm by an external pumping light at 650 to 950 nm. Such a diamond laser is produced by preparing a synthetic Ib type diamond having a nitrogen concentration within the range of 1.times.10.sup.17 to 8.5 10.sup.19 atoms/cm.sup.3, subjecting this synthetic diamond to an electron irradiation with a dose of not less than 5.times.10.sup.17 electrons/cm.sup.2, and heat-treating the synthetic diamond in a vacuum of not more than 1 Torr or in an inert gas atmosphere and at a temperature within the range of 1400.degree. to 1850.degree. C.

Abstract: A process for synthesizing a large diamond having a diameter of 8 mm or more by the temperature gradient method, wherein a (111) or (100) surface of a seed crystal having a diameter of 3 mm or more is used as a growing surface, the entire area of the growing surface is first dissolved in the diamond-stable region before crystal growth is started, the crystal growth is effected using a plug of a solvent in which the height of the central portion thereof is higher than the height of the peripheral portion thereof, the plug of a solvent has a planar or curved surface on the side where the plug of a solvent contacts a carbon source during the crystal growth, and the crystal growth is effected under such pressure and temperature conditions that the growth of the (111) or (100) surface is predominant.

Abstract: A vibration generating apparatus including a support body having a first center axis, a first spherical joint element provided at a forward end of the support body and having the center of a sphere located on the first center axis, a vibrating body having a second center axis passing through the sphere center, a second spherical joint element provided on the vibrating body and concentric complementary with the first spherical joint element to cooperate therewith to allow the vibrating body to be supported on the support member for universal movement, a rotary shaft coaxially rotatably supported within the vibrating body, a pair of eccentric weights mounted on the rotary shaft with a phase deviation of 180 degrees and in a manner symmetrical with respect to the sphere center, and a drive motor connected to the rotary shaft for driving same for rotation whereby the pair of eccentric weights are rotated about the second center axis to cause the vibrating body to move in conical motion vibration such that the sec

Abstract: A synthetic diamond heat sink which can be easily shaped and which ensures a consistently high thermal conductivity in which the diamond is a Type Ib diamond containing 50 to 100 ppm nitrogen. The synthetic diamond crystal has a shape similar to the crystal structure of a hexahedron synthesized by heating a carbon source, a solvent and a diamond seed crystal and the stability region of diamond at a high pressure. The resulting temperature gradient between the carbon source and seed crystal is adjusted to cause diamond growth on the seed crystal. The solvent employed is selected from the group of cobalt, nickel, iron, chromium and manganese. The diamond crystal is caused to grow as the temperature of the solvent is gradually decreased at a rate of 0.15 to 10.degree. C. per hour so that the temperature of the seed crystal and growning diamond crystal is within a range the lower limit of which is a temperature 20.degree. C.

Abstract: A pipe laying apparatus having an excavator for performing excavation in the earth to form a substantially horizontally extending hole, with the excavator having connected to its trailing end a leading end of at least one underground pipe at least partially located in the horizontally extending hole, an injector for injecting a viscosity imparting liquid into the earth in which excavation is being performed by the excavator to produce viscosity imparting liquid containing soil particles. A propelling device positioned against a trailing end of the pipe and is located in a starting pit. The viscosity imparting liquid containing soil particles produced by the excavator and injector are conveyed rearwardly of the excavator past an outer periphery thereof and filled in an annular gap defined between the horizontally extending hole and the pipe while the excavator and pipe are advanced by the propelling device.

Abstract: A pipe laying apparatus including an excavator propulsion unit located in a starting pit. The excavator includes an excavator body having a first axis, an excavating tool having a second axis and located at a forward end portion of the excavator body, and injection ports formed in the excavating tool for injecting a viscosity imparting liquid into soil as excavated.