Abstract: An objective lens for a pickup optical system for optically reading out information recorded in a recording medium , includes a first lens body and a second lens body integrally attached to a surface of the first lens body and having a micro Fresnel portion for focusing light to a predetermined position of the recording medium. When the objective lens is used for a pickup optical system, the micro Fresnel portion faces away from an accommodation region for accommodating the recording medium to prevent dust from attaching to the micro Fresnel portion.

Abstract: An optical lens made of plastic comprises an optically functioning part, a flange part disposed around the optically functioning part, and a gate-removed part located at an outer circumferential face of the flange part. The gate-removed part is defined by removing a residual gate part projecting from the outer circumferential face. The surface of the gate-removed part is covered with a hygroscopicity adjusting part. The hygroscopicity adjusting part is made of a material less hygroscopic than the plastic of which the optical lens is made.

Abstract: A method for molding optical glass elements including the steps of injecting molten glass material into a mold cavity through an injection port, runner and gate; cooling molten glass material in the mold cavity to a solidified state; and applying vibrations to solidified glass material in the mold cavity through a gate-forming member inserted into the mold assembly to form a gate to make a gate cut by concentration of stresses at boundary regions between the gate and the mold cavity.

Abstract: The lubricating oil for refrigerator according to the present invention is a lubricating oil for refrigerator using 1,1,1,2-tetrafluoroethane refrigerant. Having esters as base oil, its viscosity range is between 2-30 mm/s at 100.degree.C. By adding esters alone or by adding esters having different viscosity to esters base oil, or by adding polymer, the viscosity is adjusted to obtain the lubricating oil suitable for various types of refrigerators. The lubricating oil thus obtained has excellent compatibility with 1,1,1,2-tetrafluoroethane refrigerant, which is an alternative to freon, and has low hygroscopic property and high heat-resistant property.By reducing the total acid number to 0.05 mg KOH/g or less, the corrosion-resistant property and insulating property of lubricating oil are not decreased, and the lubricating oil for refrigerator having having high refrigerant stability, hydrolytic stability and insulating property can be obtained.

Abstract: When vinyl chloride resin slurry containing vinyl chloride monomer is contacted with steam in counterflow manner in a column provided with at least one perforated plate having a downcomer to remove the monomer, the lower surface of the plate is washed by hot water injection, whereby clogging of the small holes of the perforated plate is prevented.

Abstract: An attenuator for use in filtering high-frequency waves propagated in a transmission line, comprising ferrite beads having a conductor passed therethrough which are enclosed firmly within a mixture having powder of ferrimagnetic material dispersed in an organic high polymer.

Abstract: A signal editing and processing technique for converting a plurality of continuous signals, especially long term continuous audio signals respectively relating to short term still picture signals, to a transmitting signal in which signal transmission periods and pause periods are provided, having an integer ratio of time duration with each other, wherein other signals, especially the picture signals, should be transmitted. All continuous signals are sequentially converted to digital signals addressed in accordance with relevant continuous signals, and once stored in arbitrary positions of a memory, and then read out in a given multiplexed sequence corresponding to the transmission periods of the transmitting signal. The read out multiplexed digital signals are sequentially stored in another memory, and then read out with a given high speed equal to that of the signal transmission.

Abstract: A transmission system for transmitting a plurality of information signals having arbitrary time lengths through a plurality of transmission channels, wherein at a transmitter end said plurality of information signals are allotted to said plurality of transmission channels in such a manner that in each transmission channel an information signal is followed by other information signal and a control signal comprising an index of an information composed of one or more information signals, a transmission channel or channels through which said one or more information signals are transmitted and one or more timings of transition of said one or more information signals is transmitted in addition to said information signals and at a receiver end a desired information signal is selectively extracted and reproduced under the control of said control signal.

Abstract: A receiver for receiving a composite signal including a multivalue pulse code modulated information signal and a binary pulse code modulated synchronizing signal and for regenerating the information signal. The receiver comprises an identification circuit for the identifying binary pulse code signal and an identification circuit for identifying the multivalue pulse code signal to both of which the received composite signal is supplied. The synchronizing signal is detected and regenerated by using the identified signal identified by the identification circuit for identifying the binary pulse code signal. Also by using the regenerated synchronizing signal, the composite signal is pulse clamped and the pulse clamped composite signal is supplied to the identification circuit for identifying the multivalue pulse code signal and the identification is effected.

Abstract: A signal transmission system for transmitting programed information such as a programed instruction comprising at a transmitter end circuitry for producing a number of program materials and a control signal which is used at a receiver end to control the manner of sequentially connecting program materials in accordance with a response input of a student to construct at least one significant program. The system comprises at the receiver end circuitry for detecting the control signal, circuitry for extracting desired program materials in a desired sequence with the aid of the control signal in accordance with the response input of the student and apparatus for displaying the extracted desired program materials.

Abstract: A multiplex signal transmission system in which a plurality of information signals, having respectively arbitrary time durations and being arranged in time-serial form, are sequentially divided into a plurality of signal portions by a predetermined time period, said signal portions being successively allocated in time-parallel form to a plurality of transmission channels, each of which has a time duration of said predetermined time period, and being transmitted repeatedly through respectively allocated channels every said time duration, comprises a channel shift means for shifting sequentially the channel allocation of said signal portions at predetermined time periods, and a signal transmitting means for transmitting in time-parallel form said signal portions derived from said channel shift means repeatedly through every preceding channels.