Nippon Steel Corporation

Fujitsu Corporation

Yoshihiro Kaneda

Ryoichi Yoshihara

Ryousuke Wake

Hiromasa Shoji

Kenichiro Tadokoro

Tadashi Sakon

Masao Sakashita

Takashi Sekiguchi

Yoshihiro Onoda

Takao Sumiya

The invention relates to an optical transmitting device. Particularly, the invention provides a loss-of-signal detecting device that detects a loss of an optical signal received by a terminal station or a relay station, in the order of an SD and an SF. The loss-of-signal detecting device includes: an optical input unit that outputs received-optical-power reduction information and a LOS alarm based on a measuring of received optical power of an optical input signal; a synchronizing unit that extracts a synchronous clock contained in the optical input signal, and outputs an LOL alarm when the clock is asynchronous; and a loss-of-signal detecting unit that determines the presence or absence of the received-optical-power reduction information, sets the LOS alarm valid based on the output of the LOL alarm when the received-optical-power reduction information is present, and immediately sets the LOS alarm valid when the received-optical-power reduction information is absent, thereby detecting a loss of signal based on a valid LOS alarm.

Loss-of-signal detecting device

Surface treated metal materials with corrosion-resistant coating layers composed mainly of oxyacid compounds of rare earth elements (lanthanum, cerium, etc.) or Group IVA elements (zirconium, etc.), oxyacids or mixtures thereof. The corrosion resistant coating layers may also contain resins. Also provided are corrosion resistant coating layers containing rare earth element and Group IVA element compounds in resin matrixes. The corrosion resistant coating layers, particularly inorganic layers, may be covered with resin layers.

Surface treated metal material and surface treating agent

A surface-treated steel sheet is provided, at a low cost, which has high weldability and is useful for a material of containers of foods and beverages. The surface treatment is conducted by applying flattened granular tin coating deposits having a specified diameter and high adhesion on a steel sheet surface at a specified plated area ratio, and applying thereon a metallic chromium coating and a chromium hydrate oxide coating. In the surface treatment, firstly, the surface of a steel sheet is subjected to tin-plating in an acidic tin plating bath containing a conventionally used brightener in an amount of from 0,001 to 0.05 g/l so as to form flattened granular tin coating deposits having a diameter of 0.4-2.4 .mu. at a plated area ratio of 5 to 30% and to improve the adhesion to the steel sheet and decrease falling-off of the granular tin coating deposits until completion of chrome-plating, thereby the variation of the amount of tin coating being decreased. Subsequently, the sheet is plated with metallic chromium in an amount of 50-150 mg/m.sup.2, and further chromium hydrate oxide layer is formed in an amount of 2-40 mg/m.sup.2 as chromium. Thus a surface-treated steel sheet, which has satisfactory surface appearance, paint adhesiveness, under-paint-coating corrosion resistance of conventional tin-free steel sheets, and stable weldability, is producible at a low cost.

Process for producing surface-treated steel sheet superior in

A surface-treated steel sheet is provided, at a low cost, which has high weldability and is useful for a material of containers of foods and beverages. The surface treatment is conducted by applying flattened granular tin coating deposits having a specified diameter and high adhesion on a steel sheet surface at a specified plated area ratio, and applying thereon a metallic chromium coating and a chromium hydrate oxide coating. In the surface treatment, firstly, the surface of a steel sheet is subjected to tin-plating in an acidic tin plating bath containing a conventionally used brightener in an amount of from 0.001 to 0.05 g/1 so as to form flattened granular tin coating deposits having a diameter of 0.4-2.4 .mu. at a plated area ratio of 5 to 30% and to improve the adhesion to the steel sheet and decrease falling-off of the granular tin coating deposits until completion of chrome-plating, thereby the variation of the amount of tin coating being decreased. Subsequently, the sheet is plated with metallic chromium in an amount of 50-150 mg/m.sup.2, and further chromium hydrate oxide layer is formed in an amount of 2-40 mg/m.sup.2 as chromium. Thus a surface-treated steel sheet, which has satisfactory surface appearance, paint adhesiveness, under-paint-coating corrosion resistance of conventional tin-free steel sheets, and stable weldability, is producible at a low cost.

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Kawasaki, Japan

Yoshihiro Kaneda