摘要:
Crystals of an amino acid, a nucleic acid or a derivative thereof can be efficiently isolated and purified at low cost from a solution containing the crystals, bacterial cells and medium components by using a liquid cyclone.
摘要:
A grinding abnormality monitoring method and device for grinding a plurality of works of the same type are proposed which can improve the accuracy of judgment whether an abnormality is generated or not by properly setting a threshold value. According to the method or the device, by setting at least one of upper and lower limit values of a trial grinding load detected at the trial grinding of at least one of the works, an occurrence of grinding abnormality is judged when an actual grinding load detected at the actual grinding of work exceeds at least one of the upper and lower limit values thereof which varies depending on the time elapsed from the start of the actual grinding or a position of work relative to a grinding wheel.
摘要:
Provided is a driving method of a mode-locked semiconductor laser device comprising a laminated structure in which a first compound semiconductor layer, a third compound semiconductor layer having an emission region and a second compound semiconductor layer are successively laminated, a second electrode, and a first electrode. The laminated structure is formed on a compound semiconductor substrate having polarity, the third compound semiconductor layer includes a quantum well structure having a well layer and a barrier layer. The well layer has a depth of 1 nm or more and 10 nm or less. The barrier layer has an impurity doping density of 2×1018 cm−3 or more and 1×1020 cm−3 or less. An optical pulse is generated in the emission region by passing a current from the second electrode to the first electrode via the laminated structure.
摘要:
An ultrashort pulse/ultra-high power laser diode with a simple structure and configuration is provided. In a method of driving a laser diode, the laser diode is driven by a pulse current which is 10 or more times higher than a threshold current value. The width of the pulse current is preferably 10 nanoseconds or less, and the value of the pulse current is specifically 0.4 amperes or over.
摘要:
An ultrashort pulse/ultra-high power laser diode with a simple structure and configuration is provided. In a method of driving a laser diode, the laser diode is driven by a pulse current which is 10 or more times higher than a threshold current value. The width of the pulse current is preferably 10 nanoseconds or less, and the value of the pulse current is specifically 0.4 amperes or over.
摘要:
A semiconductor optical amplifier includes: a laminated structure sequentially including a first compound semiconductor layer composed of GaN compound semiconductor and having a first conductivity type, a third compound semiconductor layer having a light amplification region composed of GaN compound semiconductor, and a second compound semiconductor layer composed of GaN compound semiconductor and having a second conductivity type; a second electrode formed on the second compound semiconductor layer; and a first electrode electrically connected to the first compound semiconductor layer. The laminated structure has a ridge stripe structure. When widths of the ridge stripe structure in a light output end face and the ridge stripe structure in a light incident end face are respectively Wout, and Win, Wout>Win is satisfied. A carrier non-injection region is provided in an internal region of the laminated structure from the light output end face along an axis line of the semiconductor optical amplifier.
摘要:
Nitride semiconductor wafers which are produced by epitaxially grown nitride films on a foreign undersubstrate in vapor phase have strong inner stress due to misfit between the nitride and the undersubstrate material. A GaN wafer which has made by piling GaN films upon a GaAs undersubstrate in vapor phase and eliminating the GaAs undersubstrate bends upward due to the inner stress owing to the misfit of lattice constants between GaN and GaAs.
摘要:
[PROBLEM TO BE SOLVED] A hemorrhoid ligation apparatus that allows the operator to handle with a single hand to ligate a hemorrhoid, under minimized risk of committing improper operation, is to be provided.[MEANS FOR SOLVING] The hemorrhoid ligation apparatus (10) includes a main cylinder (12) to which an O-ring (50) for ligating the hemorrhoid is to be attached on an outer circumferential surface of a front end portion, a sub cylinder (14) air-tightly and slidably provided inside the main cylinder (12), so as to suck the hemorrhoid into inside the front end portion of the main cylinder (12) upon being drawn toward a rear end portion of the main cylinder (12), an operating fluid loaded inside the sub cylinder (14), and a plunger (16) air-tightly and slidably provided inside the sub cylinder (14), so as to pressurize the operating fluid upon being squeezed toward a front end portion of the sub cylinder (14), to thereby squeeze the O-ring (50) toward the front end portion of the main cylinder (12) with the pressurized operating fluid, thus detaching the O-ring (50) from the main cylinder (12).
摘要:
Nitride semiconductor wafers which are produced by epitaxially grown nitride films on a foreign undersubstrate in vapor phase have strong inner stress due to misfit between the nitride and the undersubstrate material. A GaN wafer which has made by piling GaN films upon a GaAs undersubstrate in vapor phase and eliminating the GaAs undersubstrate bends upward due to the inner stress owing to the misfit of lattice constants between GaN and GaAs. Ordinary one-surface polishing having the steps of gluing a wafer with a surface on a flat disc, bringing another surface in contact with a lower turntable, pressing the disc, rotating the disc, revolving the turntable and whetting the lower surface, cannot remedy the inherent distortion. The Distortion worsens morphology of epitaxial wafers, lowers yield of via-mask exposure and invites cracks on surfaces. Nitride crystals are rigid but fragile. Chemical/mechanical polishing has been requested in vain. Current GaN wafers have roughened bottom surfaces, which induce contamination of particles and fluctuation of thickness.
摘要:
A light emitting device which can be easily manufactured and can control the positions of light emission precisely, and an optical device. A first and second light emitting elements are formed on one face of a supporting base. The first light emitting element has an active layer made of GaInN mixed crystal on a GaN-made first substrate on the side thereof on which the supporting base is disposed. The second light emitting element has lasing portions on a GaAs-made second substrate on the side thereof on which the supporting base is disposed. Since the first and second light emitting elements are not grown on the same substrate, a multiple-wavelength laser having the output wavelength of around 400 nm can be easily obtained. Since the first substrate is transparent in the visible region, the positions of light emitting regions in the first and second light emitting elements can be precisely controlled by lithography.