Abstract:
There is provided a process for producing aerolein, acrylic acid, methacrolein, methacrylic acid in a safe and steady manner and in high yields, which avoids a phenomenon of occurrence of an abnormal reaction attributable to the fact that the temperature at a raw material gas outlet side becomes considerably higher than the temperature at a raw material gas inlet side, with regard to the temperature of a catalyst packed in a reaction tube at vapor-phase catalytic oxidation of propylene, isobutylene, or the like.In the process of using a reaction tube on which a plurality of catalyst layers formed in a raw material gas flow direction, a catalyst and a catalyst packing schedule are designed so that a relation between the raw material conversion rate at which the yield of the objective product becomes maximum and the raw material conversion rate at which a high and low correlation between maximum temperature of the catalyst layer present closest to a reaction gas inlet side Zin and maximum temperature of the catalyst layer present closest to a reaction gas outlet side Zout is reversed satisfies a specific condition of 0.5≦Cmax−Ccrs≦5, in which Cmax: a raw material conversion rate at which yield of the objective products becomes maximum; and Ccrs: a raw material conversion rate at which, when maximum temperature of the catalyst layer Zin is regarded as Tin, maximum temperature of the catalyst layer Zout is regarded as Tout, and the raw material conversion rate is changed, a high and low correlation between Tin and Tout is reversed.
Abstract:
A catalyst for the production of unsaturated aldehyde and unsaturated acid, obtained by loading a catalytically active component on a carrier and calcining the loaded catalyst, characterized by an average particle diameter of the catalyst of 4 to 16 mm, an average particle diameter of the carrier of 3 to 12 mm, a calcining temperature of 520 to 600.degree. C. and an amount of the catalytically active component loaded on the carrier of 5 to 80% by weight �weight of the catalytically active component)/(weight of the catalytically active component+weight of the carrier+weight of a strength improver)!, and a process for producing unsaturated aldehyde and unsaturated acid with the catalyst.
Abstract:
There is here provided a convenient bag used at the time when microorganisms which adhere to a specimen containing a solid material are extracted with a saline solution and are then examined. In this bag, a filter sheet is stuck to plastic film sidewalls so as to extend from the opening inlet to the bottom portion of the sidewalls, so that the bag is divided into two chambers. A specimen and a saline solution are poured into one of the two chambers, and the resulting extract is taken out by a pipet from another chamber.
Abstract:
A three-dimensional periodical structure whose period is about 1 μm or smaller is provided. At least two kinds of films which have two-dimensionally substantially periodical projections are successively formed in layers substantially periodical to construct structure which is substantially three-dimensionally periodical. For instance, the films are made of materials different in refractive index. The three-dimensional periodical structure whose period is about 1 μm or smaller can be obtained by a simple fabricating method. By this structure, the propagation of a wave with a specific wavelength in many solid angular directions including several axial directions parallel to the plane and the thickness direction of the layers can be cut off.
Abstract:
A lensed-fiber including a single-mode fiber having a core and a cladding, a coreless fiber having a coreless isotropic refractive index and a convex surface at a first end thereof, and a square-law index fiber having a square-law index profile. The square-law index fiber is positioned between the single-mode fiber and the coreless fiber so as to connect an end of the single-mode fiber to a second end of the coreless fiber. The lensed-fiber may be arranged in a optical module facing an optical semiconductor element which emits a light beam to be propagated through the single-mode fiber.
Abstract:
An optical fiber having a lens formed at an end thereof comprises a fiber body including a core and a cladding, and an incident light guide portion having a uniform refractive index and integrally formed at an end portion of the fiber body, wherein the incident light guide portion has a convex surface, and the core has a distal end located within the incident light guide portion at a position close to a focal point of the incident light guide portion. When the incident light guide portion is arranged in alignment with a light source such that an extremity of the convex surface of the incident light guide portion faces a light-emitting surface of the light source, assuming that an X-Y coordinate system is established wherein the X axis coincides with the optical axis of the fiber body and the Y axis coincides with a radius direction of the fiber body, the relationship expressed by the following equation is fulfilled: ##EQU1## where coordinates of the extremity of the convex surface of the incident light guide portion are (0, 0), coordinates of the light-emitting surface of the light source are (-k, 0), coordinates of the distal end of the core are (L, 0), coordinates of an incident point at which light from the light-emitting surface of the light source falls upon the convex surface of the incident light guide portion are (z, r), and the refractive index of the incident light guide portion is n. Accordingly, no phase difference of laser beams occurs when the optical fiber is connected to a semiconductor laser, making it possible to provide a high coupling efficiency optical fiber.
Abstract:
An object of the present invention is to provide a process for stably producing a catalyst for methacrylic acid production exhibiting high activity and high performance. The process for producing a catalyst for methacrylic acid production of the invention is characterized in that the water content of the catalyst ingredient powder for use in molding, temperature and humidity of a molding step, humidity and temperature of a baking step are individually controlled in the case where molding is performed by a coating method using an Mo—V—P—Cu-based hetero polyacid as an active ingredient and water or an alcohol and/or an aqueous solution of an alcohol as a binder.
Abstract:
An object of the present invention is to provide a process for stably producing a catalyst for methacrylic acid production exhibiting high activity and high performance. The process for producing a catalyst for methacrylic acid production of the invention is characterized in that the water content of the catalyst ingredient powder for use in molding, temperature and humidity of a molding step, humidity and temperature of a baking step are individually controlled in the case where molding is performed by a coating method using an Mo—V—P—Cu-based hetero polyacid as an active ingredient and water or an alcohol and/or an aqueous solution of an alcohol as a binder.
Abstract:
Disclosed is a field distribution converting optical fiber which can be massproduced and enables mutual conversion elliptical field distribution to circular field distribution or vice versa, and a laser diode module in which the field distribution converting optical fiber is used. The optical axis is assumed to be Z, either of the refractive index profiles of a core in the X and Y directions of the orthogonal three axes X, Y and Z is made into a square-law distribution profile, a slope of the refractive index profile in the corresponding X direction is made different from a slope of the refractive index profile in the Y direction. The optical axis propagating in the XZ and XY planes is caused to cyclically change in the Z direction, wherein these cycles are made different from each other to cause the cross-sectional profile of the field distribution of the optical fiber to be cyclically changed. The optical fiber length is made almost coincident with the length of the common multiple between a one-fourth cycle length of a field distribution change cycle of a light beam propagating in the XZ plane in the Z direction and a one-fourth cycle length of a field distribution change cycle of a light beam propagating in the YZ plane in the Z direction, whereby optical waves having elliptical field distribution, which are made incident into the incident side of the optical fiber are caused to outgo from the outgoing side as circular field distribution optical waves.
Abstract:
A lensed optical fiber and a semiconductor laser module, characterized in that first and second optical fibers, each including a core and a cladding, are connected to one end of a single-mode fiber, including a core and a cladding, in the order named. The core of the first optical fiber has a first square-low index distribution and a length substantially equal to 1/4 of the meandering period of light propagating through the core or an odd multiple thereof. The core of the second optical fiber has a second square-low index distribution and a meandering period different from that of the first optical fiber.