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R & D Review


No.97 January 2001

Development of ITS Technologies

ITS (Intelligent Transport Systems) is a worldwide project that dissolves various problems in the traffic society by connecting vehicle and road and person over the network, also creating ITS related industries. In Japan, five Ministries, the Ministry of Construction, the National Police Agency, the Ministries International Trade and Industry, Transport, and Posts and Telecommunications, have leadership for research and development which is promoted as a state project. Our technology has been classified into three networks systems; wired, wireless, and in-vehicle networks. We have decided on projects which should be promoted the most. Integration of various technology through immediate intra-office cooperation decides the success of ITS business.
[Key words] ITS, Vehicle, Road, Wired network, Wireless network, In-vehicle network

Long-distance Real-time Moving Picture Communications System on the Ethernet Network

We have developed a long-distance real-time moving picture communications system on the Ethernet network. Moving picture is transmitted through the Ethernet network, a LAN (Local Area Network) which is most widely used.
On this system, moving picture is encoded by MPEG2 (Moving Picture Experts Group 2), and multicast through the Ethernet network consisting of SMF (Single Mode Optical Fiber) and communication equipment.
This system has easy access to moving picture by GUI (Graphic User Interface).
This paper describes the network architecture and the function of device.
[Key words] Ethernet, MPEG2, Moving picture transmission, Long-distance transmission, Optical fiber, IP multi- cast

Development of Bi-Directional Optical Transmission Unit MP-6000A

Recently, in the hi-tec world, various optical transmission equipments have been widely deployed. Optical transmission system using optical fiber instead of ordinary metallic communication cable has superior low attenuation properties and immunity from electro-magnetic interference.
We have been developing various optical equipments which can transmit multiplexed analog and digital signals over fibers. One of the such equipments is the model MP-6000.
The model MP-6000 has larger capacity and higher optical output power and higher bit rates transmission speed than our conventional model MP-5000.
Model MP-6000 adopts a redundant system and self diagnosis system to increase reliability, and can tansmit 1536 digital signals and 512 analog signals using a pair of single mode fibers.
In this report, we introduce our latest model MP-6000A. The model MP-6000A consists one CPU board and up to eight(8) I/O boards and a power supply unit. The CPU board and various I/O boards are installed in a 19 inch unitcase. The MP-6000A can transmit 288 digital signals and 96 analog signals up to 30km over a pair of single mode fibers. This is a down-sized compact model of the MP-6000, and the redundancy is omitted.
We are confident that a suitable optical transmission system satisfying any requirement can be easily constructed using our model MP-6000A.
[Key words] Single mode optical fiber, Multiplexing, Unit constitution

Development of the SZ Slotted Core Cable with 4-Fiber Ribbons Divisible into Fiber Units

Recently, fiber ribbon slotted core type cables are the most popular optical fiber cable for trunk lines or wiring facilities . Especially the 4-fiber ribbon is very popular. When branching off this 4-fiber ribbon to a user facility normally it is divided into two core units to be connected to the other optical fibers extending to different lines. However, dividing the cable into two core units and the connection work which follows is difficult. To solve these problems, we have developed the SZ-slotted Divisible 4-fiber ribbon which can easily be divided into two core units. A 4-fiber ribbon with 2× 2-fiber ribbons is laid side by side. 2-fiber ribbons are wrapped as an unit by a binding layer to prevent separation of individual core when dividing. The 4-fiber ribbons are accommodated in the SZ slotted rod is superior in structure for dividing afterward. While the 4-fiber ribbon has not been used for optical fiber cables in cold districts where the temperature is below -20 °C, the 2-fiber ribbon is used instead. However our durability test of our divisible 4-fiber ribbon cable in cold districts which were implemented under cooperation of Hotnet showed satisfactory durability.
[Key words] Optical fiber cable , Fiber ribbons , SZ , Dividing afterward, Durability test in cold districts

Multi-Cable Installation of Optical Cables

We have developed a remarkable installation method and tool with which two or more optical fiber cables can be additionally and easily installed without putting new cables beneath or affecting the pre-installed cables under operation in a cable duct.
[Key words] Optical cable, Installation method, Multi-cable installation, Less frictional

A Study on Optical Fiber Cable Sheath Materials for Multi-Cable Installation

With demand for optical access network increasing rapidly, multi-cable installation is means for effectively making use of the conduit line and using optical fibers efficiently. To realize this kind of installation, we have evaluated sheath materials with low friction. In this paper, we introduce our experiments on decreasing the friction by adding lubricants to sheath materials using the conventional linear low density polyethylene (L-LDPE) and high density polyethylene (HDPE) as the base polymers. We evaluated the reliability of lubricant added sheath materials and performed a test installment to a simulation conduit line.
Lubricant evaluation results used in L-LDPE sheath materials showed that fatty acid amide lubricant was more effective than silicone. Because HDPE has a higher degree of crystallinity than L-LDPE, it is more durable against abrasion and therefore is a suitable material for multi-cable installation. Results of evaluation of the friction coefficient and the effect of lubricant showed that HDPE sheath materials with no lubricant had equal or superior friction coefficient than L-LDPE sheath materials added with the optimum amount of lubricant. With certain fatty acid amide lubricant, even though its effect was less than on L-LDPE, it was able to decrease friction in HDPE. We confirmed that both L-LDPE and HDPE added with lubricant had sufficient characteristics necessary for sheath materials. From the simulation conduit line having nominal diameter of 75mm, length of 50m, we obtained results which matched well with the sheet experiment.
HDPE sheath materials are ideal for multi-cable installation as they have very low friction without the need of additives. They are also durable against abrasion and have superior mechanical characteristics, enabling very thin sheaths. Having no additives is also a merit for recycling the material.
[Key words] Polyethylene, HDPE, L-LDPE, Lubricant, Fatty acid amid, Sheath material, Friction, Abrasion, Multi-cable installation, Installation conduit line

Installation of Molded Joint by Curable PE Block Insulation for 275kV XLPE Cables in the Kitayono Line

In demand of increasing electric power, large capacity transmission lines with 275kV XLPE insulated cable has been installed since 1989 in Japan.
Extruded and molded joint (EMJ) are now used for the extra-high-voltage XLPE insulated cable which have excellent electrical performance, high long-term reliability and simpler and more compact construction than conventional types.
However, EMJ requres numerous machine operation, specialized and skilled workmanship and consumes assembly time.
We have developed a new type of joint, called the Block Molded Joint (BMJ), which combines the advantages of EMJ, but shortens the time taken for jointing and simplifies the jointing quality items. The BMJ is formed with curable polyethylene insulation pre-molded block (CPEI, BLOCK) is made of the same material as the cable insulation in the factory, the cables are then inserted into the BLOCK and crosslinked together on site.
This paper reports on the BMJ and its simplified quality control and skills of jointing work. It has shortened assembly time compared with the EMJ. We also report on its first application to 275 kV long distance transmission line (Kitayono Line of The Tokyo Electoric Power Co. Inc.).
[Key words] XLPE cable, Cross-linked polyethylene, Joint, Pre-molded joint (PMJ), Molded joint, Extruded molded joint (EMJ), Taping molded joint (TMJ), Block molded joint (BMJ)

Development of a Compact Type Y-Joint for 66/77kV XLPE Cables

We have developed the compact type Y-joint for 66/77kV XLPE cables to minimize the cost and space for manholes and to simplify the assembly.
Although the new Y-joint is classified in one group for cable sizes 500mm2 and below, compared to conventional types, it has been outstandingly downsized i.e. by 400mm in length, 300mm in width and 100mm in height, and its wight has been reduced to a fourth.
Further more, we have also confirmed that the joint can be applied to up to cable sizes of 600mm2.
[Key words] Y-joint, Simplifying the assembly, Minimizing space for manholes, Applicable up to the cable size of 600mm2

Development of Cable Locators for Control Cables

In power stations and substations, central control panels are connected to other equipment by thousands of cables. These cables go through the walls and the floors by several hundred meters from several meters long. Under such conditions, a cable locator that can locate cables among thousands outside the control room is desirable. Usually electromagnetic induction-types, or electrostatic coupling-types (a pulse wave-type and a sinusoidal wave-type) are used as the cable locator. But both are not applicable when the far-end of the cable is not accessible. The cable can not be located by the electromagnetic induction-type when the conductor is not connected at the far-end by the ground or the conductor of the adjoining cable and a loop is not formed. With the electrostatic coupling-type (sinusoidal wave-type), if the conductor is grounded at the far-end the cable can not be located. If the length of the cable is fully long, it can be located with the pulse wave-type regardless of the condition at the end of others. However, it can not be located with the short cable, because a signal is denied by the negative reflection pulse wave from the far-end. To overcome these problems, we have developed a cable locator, which can locate a cable when the conductor of the cable, is either grounded or released at the far-end. The cable locator is used with an electromagnetic induction-type and an electrostatic coupling-type together. It can locate without switching from electrostatic coupling to the electromagnetic induction.
[Key words] Central control panel, Cable, Cable locator, Electromagnetic coupling, Electrostatic coupling, Sinusoidal wave-type, Pulse wave-type, Far-end, Transmitter, Receiver

The Degradation Diagnosis of Low Voltage Cables Used at Nuclear Power Plants

Low voltage cables which have been used for the supply of electric power and the propagation of control signals in nuclear power plants must be sound for safe and stable operation. The long use of nuclear power plants has been reviewed, and the degradation diagnosis to estimate the soundness of low voltage cables has been emphasized. Mitsubishi Cable Industries has established a degradation diagnosis method of cables which convert the velocity of ultrasonic wave in the surface layer of the cable insulation or jacket into breaking elongation, and has developed a degradation diagnosis equipment of low voltage cables used at nuclear power plants in cooperation with Mitsubishi Heavy Industries.
This equipment can be moved by an ultrasonic probe by sequential control and measure the ultrasonic velocity automatically. It is capable of a fast and sensitive diagnosis of the cables.
We report the outline of this degradation diagnosis equipment and an example of the adaptability estimation at an actual nuclear power plant.
[Key words] Nuclear power plant, Low voltage cable, Polyvinyl chloride, Ethylene-propylene rubber, Degradation diagnosis, Ultrasonic wave

Seals Used for Semiconductor Manufacturing Devices

In the semiconductor manufacturing, various kinds of gases and liquids have been used under vacuum condition and irradiation of plasma. Accordingly, seals used for semiconductor manufacturing devices were required low leakage under vacuum condition, and also good resistance for chemicals, plasma and high temperature. Corresponding to such needs, various kinds of metal and rubber seals were developed by using our technology.
In the metal seals, an ultra lapping Metal-O-Ring for mass flow controller, SUNCUP® for integrated gas system, and an aluminum jacket seal which suppressed gas permeation were developed. Rubber materials such as SUNELAST® I , SUNELAST® II , material number 1364-70, and 1349-80 were also developed. Further, TRI seal that uniquely designed for gate valve was created.
In this report, characteristics of these newly developed seals were explained.
[Key words] Seal, Semiconductor, Vacuum, Metal O Ring, SUNCUP, Chemical Resistance, Plasma Resistance, Fluorocarbon Elastomer, Sticking, SUNELAST, UE Modify, RE-O Modify, Particle, Dovetail Groove

Development of Low-Temperature and High-Rate Lithium-Ion Batteries

Lithium-ion batteries have weak points in low-temperature and high-rate performance. We take aim at overcoming these weak points and have developed lithium-ion batteries durable under low-temperature and high-rate. The minimum operating temperature of the newly developed MC-18650A(cylindrical type, diameter:18mm, height:65mm) is 10°C lower than that of our former types. We also confirmed high-rate discharge performance (maximum operating current is about twice larger than our old type battery). In order to develop a high performance battery, it is important that the elements of positive electrode, negative electrode, and electrolyte are improved. We report on the outline of technical points of low-temperature and high-rate performance battery and then report the performance (low-temperature, rate, cycle life, storage, and safety property) of the MC-18650A.
[Key words] Lithium-ion battery, Low-temperature, High-rate, Positive electrode, Negative electrode, Electrolyte

Development of Ultraviolet AlGaN Photodiodes

With the progress of the information technology (IT) revolution and rapid expansion of information volumes, the demand for more highly integrated LSIs which can be incorporated into computers has increased. The establishment of a smaller design rule of electronic circuits is essential to promote the highly integrated LSIs, while the wavelength of a light source incorporated into a stepper, which is one type of exposure tools on photo-lithography systems, is required to be shortened further. A stepper in which the ArF excimer laser (wavelength: 193 nm) is incorporated as the exposure light source will be the main one in use in the next generation. Meanwhile, for the measurement of ultraviolet (UV) rays, photodetector components (photodiodes) with Si are used. However, light sensitivity often deteriorates due to radiation damage, particularly in the far-UV region which presents a high photon energy with 200 nm or shorter wavelength. Our recently developed UV photodetector was manufactured with an AlGaN-based chemical compound semiconductor which exhibits an exceptionally high chemical bonding strength and is highly resistant to mechanical and heat stresses compared to Si. Results of a harsh endurance test in which far-UV rays (wave length: 193 nm) were irradiated revealed that the sensitivity of the Si-based photodetector was reduced by 40%, while that of the AlGaN UV photodetector remained unchanged. Accordingly, the AlGaN UV photodetector developed by us was confirmed to present sensitivity and endurance sufficient to be used for the measurement of far-UV rays of lasers such as the ArF exicmer laser.
[Key words] Ultraviolet rays, Photodetector, Shottkey barrier, Photodiodes, Exicmer laser

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