New fault locating system for air-insulated substations usingoptical current detector

The authors present the basic philosophy, construction, design features, and test results of a new fault locating system. This fault locating system helps to shorten the time required for restoration of service after the occurrence of a busbar fault in an air-insulated distribution substation. Recent optical and electronic technologies allow the design of a highly accurate and compact fault locating system which consists of optical current detectors using the Faraday effect and a fault locating processor using a digital data processing technique. The fault location is carried out by discriminating between the directions of zero-sequence currents. Through various tests and field operations, it has been confirmed that the system has sufficient performance for practical applications     

Revolving Vernier Mechanism Controls Size of Linear Homomultimer

A new kind of the Vernier mechanism that is able to control the size of linear assembly of DNA origami nanostructures is proposed. The mechanism is realized by mechanical design of DNA origami, which consists of a hollow cylinder and a rotatable shaft in it connected through the same scaffold. This nanostructure stacks with each other by the shape complementarity at its top and bottom surfaces of the cylinder, while the number of stacking is limited by twisting angle of the shaft. Experiments have shown that the size distribution of multimeric assembly of the origami depends on the twisting angle of the shaft; the average lengths of the multimer are decamer, hexamer, and tetramer for 0°, 10°, and 20° twist, respectively. In summary, it is possible to affect the number of polymerization by adjusting the precise shape and movability of a molecular structure.     

Magnetic Torque Measurements on Bi2201 Single Crystal in High Magnetic Fields

The magnetic field direction dependence of the magnetic torque in the superconducting state of Bi ₂ Sr _1.65 La _0.35 CuO ₆₊ (Bi2201) single crystal has been measured in several static magnetic fields up to 200 kOe. The applied field dependence of the anisotropy parameter, , defined by the square root of the effective mass ratio has been obtained by fitting the magnetic torque curves at 17 K by means of the effective mass model. For Bi ₂ Sr ₂ CaCu ₂ O ₈₊ (Bi2212), the values up to 210 kOe were reported previously. At each field, for Bi2201 is larger than that for Bi2212. Since the value decreases as the field increases both for Bi2201 and Bi2212, the reduction of by the application of the high magnetic field is considered to be common for Bi-based layered superconductors.     

Spinal amino acid release and precipitated withdrawal in rats chronically infused with spinal morphine

Glutamate receptors are implicated in the genesis of opioid tolerance and dependence. Factors governing release of amino acids in systems chronically exposed to opiates, however, remain undefined. Using rats, each prepared with a spinal loop dialysis catheter and with a chronic lumbar intrathecal infusion catheter connected to a subcutaneous minipump, the release of amino acids before and during antagonist-precipitated withdrawal in unanesthetized rats was examined. Spinal infusion of morphine (20 nmol/micro l/hr) for 4 d had little effect on resting release of amino acids. In morphine-infused, but not saline-infused, rats naloxone (2 mg/kg, i.p.) evoked an immediate increase in the release of L-glutamate (299 +/- 143%) and taurine (306 +/- 113%) but not other amino acids. The magnitude and time course of the release of these amino acids significantly correlated with behavioral indices of withdrawal intensity. Acute intrathecal pretreatment immediately before naloxone with clonidine (20 microg; alpha2 agonist), MK-801 (3 microg; noncompetitive NMDA antagonist), or aminophosphonopentanoic acid (AP-5; 3 microg; competitive NMDA antagonist) suppressed naloxone-induced increases in spinal L-glutamate and taurine release and behavioral signs of withdrawal in spinal morphine-infused rats. Results point to a correlated increase in spinal L-glutamate release, which contributes to genesis of the opioid withdrawal syndrome. Agents such as clonidine that suppress opioid withdrawal may owe their action to an inhibition of excitatory amino acid release. The effects of MK-801 and AP-5 suggest a glutamate-evoked glutamate release.     

Measurement method using coupled transmission lines for voltage transients on the distribution line

It is well known that voltage transients are caused by the operation of switchgears in a power system. The voltage transients travel along the power line as a traveling wave, and cause malfunction of electrical devices, communication systems, and the operational error of a control system. The voltage transients at the making operation of switchgear were examined to obtain the fundamental data for considering the immunity of communication systems used on a power system. However, it was difficult to observe the voltage transients using the potential transformer and the capacitance potential device because the transients were very rapid. Therefore, a measurement method using the coupled transmission line system is proposed to measure the high-speed and high-voltage transients, and the actual experimental results on the 6.9-kV power system are presented. This method enables the measurement of high-speed voltage transients in out of contact with the power system.     

In-Plane Anisotropy of the Upper Critical Field of La2−x Sr x CuO4 in the Underdoped and Overdoped Regimes

For La_2–x Sr _x CuO₄ single-crystals in the underdoped and overdoped regimes, we have measured the electrical resistivity along the c-axis, _c , under constant magnetic fields, changing the field direction in the ab-plane. At x=0.08, 0.12 and 0.16 in the underdoped and almost optimally-doped regimes, clear anisotropy of _c with the fourfold symmetry in the ab-plane has been observed. This symmetry is regarded as the fourfold symmetry of the upper critical field, H _c2, and explained as being mainly due to the anisotropy of the superconducting energy gap owing to the d_x ^{2-y 2} pairing. The magnitude of the fourfold component of H _c2, H _c2/H _c2, is largest in x=0.08 among the three crystals. At x=0.20 in the overdoped regime, no clear fourfold symmetry has been observed. It appears that the fourfold symmetry is easy to observe in the underdoped regime rather than in the overdoped regime.     

On Active Noise Control Systems With Online Acoustic Feedback Path Modeling

The presence of strong acoustic feedback degrades the convergence speed of the active noise control (ANC) filter, and in the worst case the ANC system may become unstable. A fixed feedback neutralization filter, obtained offline, can be used to neutralize the acoustic feedback. The feedback path, however, may be time varying, and we may need continual adjustments during online operation of the ANC system. This paper proposes a new method for online modeling of the acoustic feedback path in ANC systems. The proposed method uses three adaptive filters; a noise control filter, a feedback path modeling (FBPM) filter, and an adaptive noise cancelation (ADNC) filter. The objective of ADNC filter is to remove the disturbance from the desired response of FBPM filter. In comparison with the existing method, which works only for predictable noise sources, the proposed method can work, as well, with the broadband noise sources. The computer simulations are carried out for narrowband (predictable) (case I) and broadband (random) noise sources (case II). It is demonstrated that the proposed method performs better than the existing method in both cases     

Long-term observations of uterine contractions in nonpregnant dogs

Uterine contractile activity in nonpregnant conscious dogs was investigated based on 2- to 6-mo-long continuous recording by means of a chronically implanted force transducer. We found that nonpregnant uterine contractile activity could be classified into six major patterns: sporadic contractions, weak and strong tonic contractions, weak and strong phasic contractions, and phasic contraction bursts. The contractile patterns during proestrus and estrus were the most active, with strong phasic and tonic contractions and phasic contraction bursts. The phasic and tonic contractions were inhibited dose-dependently by a beta 2 adrenergic agonist, ritodrine, and reproduced by an alpha 2 adrenergic agonist, clonidine. In contrast, the cholinergic inhibitors atropine and hexamethonium did not affect the spontaneous occurrence of these contractions, although bethanechol evoked uterine contractions. Oxytocin and prostaglandin F2 alpha-induced contractions were phasic during estrus, whereas they showed tonic increases with phasic contractions during proestrus, diestrus, and anestrus, and these contractions did not resemble the spontaneous contractions. In conclusion, the nonpregnant uterus contracts continuously in harmony with the estrous cycle phases, and its contractile activity is enhanced by alpha adrenergic receptors and inhibited by beta 2 adrenergic receptors.     

Application of a power line maintenance information system usingOPGW to the Nishi-Gunma UHV line

Tokyo Electric Power Company, Inc. began operation of the Nishi-Gunma UHV trunk line, the first 1000 kV designed power line in Japan, in April, 1992. This line is expected to be the key line in a major trunk-line system that is being developed. It traverses high-altitude mountainous areas subject to severe environmental and meteorological conditions for a long distance. A system using composite fiber-optic overhead ground wire (OPGW) is constructed to obtain precise information on this line for maintenance purposes. This system comprises three major functions: (1) meteorological and facility's monitoring for gathering meteorological data on such elements as winds, and icing and snow accretion, and for evaluating the corresponding reaction of the components such as conductor tension, and strain in the tower structure; (2) industrial TV monitoring for visual observation of weather, surrounding conditions and site facilities; and (3) fault section location for pinpointing faults quickly and determining the maintenance office that should respond to the faults. This is done by estimating the fault section accurately around the boundaries of the maintenance jurisdictions. This paper describes the development of these functions and results obtained from practical operation