Abstract: There is provided a method for producing an optical fiber having low attenuation, the optical fiber including a core that contains an alkali metal element. An optical fiber preform that includes a core part and a cladding part is drawn with a drawing apparatus to form an optical fiber, the core part having an average concentration of an alkali metal element of 5 atomic ppm or more. During the drawing, the time the temperature of glass is maintained at 1500° C. or higher is 110 minutes or less. The drawing speed is preferably 1200 m/min or more and more preferably 1500 m/min to 2300 m/min. The optical fiber preform preferably has a diameter of 70 mm to 170 mm and more preferably 90 mm to 150 mm.

Abstract: An optical fiber preform has a core portion having a first core portion including a central axis, a second core portion disposed around the first core portion, and a third core portion disposed around the second core portion. The first core portion contains 10 atomic ppm or more of an alkali metal and 10 to 600 atomic ppm of chlorine, the second core portion contains 10 atomic ppm or less of the alkali metal and 10 to 600 atomic ppm of chlorine, and the third core portion contains 10 atomic ppm or less of the alkali metal and 2,000 atomic ppm or more of chlorine. An optical fiber has a core region doped with an alkali metal and chlorine, wherein the minimum concentration of chlorine in the core region is 1,000 atomic ppm or more, and the average concentration of the alkali metal therein is 0.2 atomic ppm or more.

Abstract: There is provided a semiconductor device having a reduced number of external terminals allocated for address input to receive access from outside, while realizing a high-speed response to an access from outside. The semiconductor device employs, in order to allow other external devices to directly access resources it possesses in its own address space, in an external interface circuit, external terminals which input a part of the address signal required for access from outside, a supplementary register which supplements the upper portion of address information that has been input from the external terminals, a mode register accessible from outside, and an address control circuit which generates an address signal to access the address space in a form based on information input from the external terminals, required supplementary information, and mode information of the mode register.

Abstract: A method for producing an optical fiber preform according to the present invention includes a collapse step of collapsing a silica-based glass tube by heating with a heat source continuously traversed in the longitudinal direction of the glass tube to form a first glass rod to be formed into a core part or part of a core part of an optical fiber, the glass tube having an inner surface doped with an alkali metal, in which the glass tube has a maximum alkali metal concentration of 500 to 20,000 atomic ppm, a maximum chlorine concentration of 0 to 1000 atomic ppm, and a maximum fluorine concentration of 0 to 10,000 atomic ppm, and in which in the collapse step, the maximum temperature of the outer surface of the glass tube is 2000° C. to 2250° C., and the traverse speed of the heat source is 30 mm/min to 100 mm/min.

Abstract: A method for producing an optical fiber preform according to the present invention includes an etching step of heating a silica-based glass tube using a heat source continuously traversed in the longitudinal direction of the glass tube to etch the inner surface portion of the glass tube containing impurities while an etching gas is allowed to flow into the glass tube. The glass tube has a maximum alkali metal concentration of 500 to 20,000 atomic ppm, a maximum chlorine concentration of 0 to 1000 atomic ppm, and a maximum fluorine concentration of 0 to 10,000 atomic ppm. In the etching step, the maximum temperature of the outer surface of the glass tube is in the range of 1900° C. to 2250° C., and the heating time is set to a time equal to or less than a time (min) given by ( 7 - alkai ? ? metal ? ? concentration ? ? ppm 5000 ) .

Abstract: There is provided a method for producing an optical fiber preform used in producing an optical fiber having low attenuation. The production method includes (1) a rod formation step of forming a glass rod of a silica glass containing an alkali metal element, the average concentration of the alkali metal element being 5 at·ppm or more, (2) a heat treatment step of heat-treating the glass rod, (3) a core part formation step of forming an alkali metal element-free silica glass layer having a chlorine concentration of 6000 at·ppm or more around the perimeter of the glass rod heat-treated in the heat treatment step to form a core part including the glass rod and the silica glass layer, and (4) a cladding part formation step of forming a cladding part of a silica-based glass having a lower refractive index than the core part around the perimeter of the core part.

Abstract: An optical fiber preform includes a core portion, in which the core portion includes an alkali-metal-doped core glass portion doped with an alkali metal, the maximum concentration of oxygen molecules in the core portion is 30 mol ppb or more, and the average concentration of the alkali metal in the core portion is 5 atomic ppm or more. A method of manufacturing an optical fiber preform includes an alkali-metal-doping step of doping a pipe composed of silica-based glass with an alkali metal, an oxygen-molecule-doping step of doping the glass pipe with oxygen molecules, and a collapsing step of collapsing the glass pipe by heating the glass pipe, in which the optical fiber preform is manufactured.

Abstract: A method includes a first step of joining a multimode fiber to a first end of an optical fiber being a specimen, allowing light to propagate from the multimode fiber to the specimen, measuring an intensity of light from a second end of the specimen, and determining a first power spectrum; a second step of joining the multimode fiber to a first end of a reference fiber having bending loss higher than that of the specimen, allowing light to propagate from the multimode fiber to the reference fiber, measuring an intensity of light from a second end of the reference fiber, and determining a second power spectrum; a third step of determining a difference spectrum by subtracting the second power spectrum from the first power spectrum; and a fourth step of determining a higher-order mode cutoff wavelength of the specimen on the basis of a shape of the difference spectrum.

Abstract: Provided is an optical fiber having a large relative refractive index difference and a reduced transmission loss, as well as a manufacturing method therefor. An optical fiber preform 100, which is made of silica glass as the main element and which includes a core region having a relative refractive index difference of 2.0% or more and less than 3.0% on the basis of the refractive index of pure silica glass and a first cladding region provided around the core region and having a relative refractive index difference of ?0.8% or more and less than ?0.3% on the basis of the refractive index of pure silica glass, is drawn into a glass fiber. The glass fiber thus drawn is passed through an annealing furnace 21 installed below a drawing furnace 11, whereby the cooling rate of the glass fiber is restrained as compared with the case where it is cooled by air.

Abstract: Compounds useful as GnRH receptor antagonists are provided. The present inventors have further examined propane-1,3-dione derivatives and confirmed as a result that a propane-1,3-dione having 2-(1,3-dihydro-2H-benzimidazol-2-ylidene), or a compound which has benzene or thiophene ring substituted with a group derived from 1-hydroxymethyl, shows excellent availability, in addition to its excellent GnRH receptor antagonism, thereby accomplishing the invention. Since the compound of the invention shows excellent availability, in addition to its strong GnRH receptor antagonism, it can be expected that it exerts superior drug effect in the living body, and it is useful for the treatment of sex hormone dependent diseases such as prostate cancer, breast cancer, endometriosis, uterine leiomyoma, benign prostatic hypertrophy and the like.

Abstract: In a glass processing method according to the invention, in the case of performing chemical vapor deposition or diameter shrinkage of a substrate glass tube G by relatively moving a heating furnace 20 comprising a heating element 21 for annularly enclosing the circumference of the substrate glass tube in a longitudinal direction of the substrate glass tube G with respect to the substrate glass tube G in which an outer diameter is 30 mm or more and a wall thickness is 3 mm or more and is less than 15 mm and an ovality of the outer diameter is 1.0% or less using a glass processing apparatus 1, a temperature of at least one of the heating element 21 and the substrate glass tube G is measured and the amount of heat generation of the heating element 21 is adjusted based on the measured temperature.

Abstract: In a glass processing method according to the invention, in the case of performing chemical vapor deposition or diameter shrinkage of a substrate glass tube G by relatively moving a heating furnace 20 comprising a heating element 21 for annularly enclosing the circumference of the substrate glass tube in a longitudinal direction of the substrate glass tube G with respect to the substrate glass tube G in which an outer diameter is 30 mm or more and a wall thickness is 3 mm or more and is less than 15 mm and an ovality of the outer diameter is 1.0% or less using a glass processing apparatus 1, a temperature of at least one of the heating element 21 and the substrate glass tube G is measured and the amount of heat generation of the heating element 21 is adjusted based on the measured temperature.

Abstract: The invention relates to an optical fiber employable in an optical communication system using Raman amplification and adapted to improve OSNR and suppress bending loss at the same time, and the like. The optical fiber is a silica-based optical fiber having a depressed refractive index profile constituted by at least a core, an inner cladding having a low refractive index, and an outer cladding, an effective area Aeff of 110 ?m2 or more at the wavelength of 1550 nm, and a fiber cutoff wavelength ?C of 1.3 ?m or more but 1.53 ?m or less. The depressed refractive index profile is designed such that the ratio Ra(=2b/2a) of the diameter of the inner cladding to the diameter of the core is 2.5 or more but 3.5 or less and that the relative refractive index difference ?? of the inner cladding with respect to the outer cladding is at least the relative refractive index difference ??min where the bending loss at the wavelength for use is minimized but not exceeding (??min+0.06) %.

Abstract: There is provided a semiconductor device having a reduced number of external terminals allocated for address input to receive access from outside, while realizing a high-speed response to an access from outside. The semiconductor device employs, in order to allow other external devices to directly access resources it possesses in its own address space, in an external interface circuit, external terminals which input a part of the address signal required for access from outside, a supplementary register which supplements the upper portion of address information that has been input from the external terminals, a mode register accessible from outside, and an address control circuit which generates an address signal to access the address space in a form based on information input from the external terminals, required supplementary information, and mode information of the mode register.

Abstract: It is intended to provide a compound useful as a GnRH receptor antagonist. The inventors further investigated propane-1,3-dione derivatives. As a result, they confirmed that a compound having a benzene ring or a thiophene ring substituted with a group represented by —SO2—R3 in a propane-1,3-dione derivative having 2-(1,3-dihydro-2H-benzimidazol-2-ylidene) has an excellent GnRH receptor antagonistic effect and accomplished the present invention. Because the compound of the present invention has a potent GnRH receptor antagonistic effect, it is useful for the treatment of sex hormone-dependent diseases, particularly GnRH-related diseases. Further, because the compound of the present invention has an excellent metabolic stability in human and few drug interactions, therefore it has preferable characteristics as a pharmaceutical used for the above-mentioned diseases.

Abstract: A reaction solution is mixed in a short period of time with excellent stir efficiency. A stir rod 19 is vertically reciprocated in a reaction solution 7 during the stirring of the solution.

Abstract: An optical fiber having excellent strength that can be manufactured at low cost, as well as a method for making such optical fiber, is provided. An optical fiber 1 is a silica-based optical fiber comprising a core 11, an optical cladding 12 surrounding the core 11, and a jacketing region 13 surrounding the optical cladding 12 and having a uniform composition throughout from the internal circumference to the outer circumference. A compressive strained layer having a residual compressive stress is provided at the outermost circumference of the jacketing region 13.

Abstract: To provide a novel and excellent method for treating and/or preventing prostatic cancer, benign prostatic hyperplasia, acne, seborrhea, hirsutism, baldness, alopecia, precocious puberty, adrenal hypertrophy, polycystic ovary syndrome, breast cancer, lung cancer, endometriosis, leiomyoma and the like based on selective inhibitory activity against 17?HSD type 5. It was found that an N-sulfonylindole derivative, where the indole ring is substituted by a carboxy group, a carboxy-substituted lower alkyl group or a carboxy-substituted lower alkenyl group at its carbon atom, has potent selective inhibitory activity against 17?HSD type 5 and may become a therapeutic agent and/or preventive agent for benign prostatic hyperplasia, prostatic cancer and the like without accompanying adverse drug reactions due to a decrease in testosterone, and the present invention has thus been completed.

Abstract: A fiber optic device outputs, at high conversion efficiency, an idler lightwave having a wavelength ?2 different from the wavelength of a signal lightwave by converting the signal lightwave having an optional wavelength ?1 in a wide wavelength band. The fiber optic device comprises a wavelength tunable pump light source for outputting a pump lightwave having a wavelength of 2×(?1?1+?2?1)?1; a optical coupler for coupling and outputting the pump lightwave and the signal lightwave; and an optical fiber having a length of 450 m or less, the zero-dispersion wavelength thereof being in the wide wavelength band, the dispersion slope thereof at the zero-dispersion wavelength being +0.01 ps/nm2/km or more and +0.045 ps/nm2/km or less, wherein the optical fiber allows propagation of the signal lightwave and the pump lightwave output from the optical coupler, and generates an idler lightwave by means of the nonlinear optical phenomenon that occurs during such propagation.

Abstract: The present invention relates to an optical fiber which has a structure for further increasing an FOM (=|dispersion|/loss) and which can be applied to a dispersion compensation module. The optical fiber is mainly composed of silica glass and has a core region including a center of an optical axis, a depressed region surrounding the core region, a ring region surrounding the depressed region, and a cladding region surrounding the ring region and doped with F. As compared with the refractive index of pure silica glass, a relative refractive index difference of the core region is greater than 2% but less than 3%, a relative refractive index difference of the depressed region is ?1% or more but ?0.5% or less, a relative refractive index difference of the ring region is 0.01% or more but 0.24% or less, and a relative refractive index difference of the cladding region is ?0.3% or more but ?0.1% or less. The FOM at the wavelength of 1550 nm is 250 ps/nm/dB or more.