Utilization of Precast Concrete Elements in Building

Precast concrete components can be used in building construction within a comprehensive “closed” system, or as separate elements in conjunction with any building method. The feasibility of this second possibility was examined within the framework of a conventional building system and the following alternatives of elements utilization: prestressed modular floor slabs, exterior walls, and a combination of slabs and exterior walls. Each of these alternatives was compared to the conventional system without precast elements. The following criteria were used as a basis for the comparison: the labor requirement, the direct building cost (labor and materials), the construction time, and other considerations of more subjective nature. The findings of the study indicated that the utilization of precast elements might considerably reduce the labor requirement on site, and the project construction time. The direct building costs were almost unaffected by the alternative solutions.     

A novel frequency-multiplication device based on three-terminalballistic junction

In this letter, a novel frequency-multiplication device based on a three-terminal ballistic junction is proposed and demonstrated. A 100 nm-size, three-terminal ballistic junction and a one-dimensional (1D), lateral-field-effect transistor with trench gate-channel insulation are fabricated from high-electron-mobility GaInAs/InP quantum-well material as a single device. The devices show frequency doubling and gain at room temperature. The performance of these devices up to room temperature originates from the nature of the device functionality and the fact that the three-terminal device extensions are maintained below the carrier mean-free path. Furthermore, it is expected that the device performance can be extended up to THz-range     

Liquid helium cooled sample stage for scanning electron microscope

A cryogenic stage is described for use with a Cambridge S4-10 scanning electron microscope. The stage is operated with liquid helium in direct contact with the back of the sample to be irradiated by the electron beam. This bath cryostat principle will work at temperatures between 1.5 K and 4.2 K with good cooling performance. The installation of the stage within the microscope does not require any modification of the microscope chamber or the detector arrangement. A precision adjustment of the sample perpendicular to the electron beam is achieved by micrometric screws.     

Resistive state and charge imbalance waves in superconducting indium bridges with large cross section

We have investigated the Josephson behavior in indium microbridges with 2 µm thickness, 5–8 µm width, and 9–21 µm length. The resistive behavior of the bridges can be described by a dynamic model consisting of an ideal Josephson oscillator emitting charge imbalance waves into the adjacent superconductor. From the analogy between the charge imbalance wave equation and the telegraph equation a useful equivalent circuit is obtained, as pointed out recently by Kadin et al. The Josephson behavior in the different regimes of amplitude and frequency of the rf current superimposed upon the dc current is discussed.     

Endoscopic injection of botulinum toxin for biliary sphincter of Oddi dysfunction

A 66-year old man was admitted to our hospital because of vomiting, diarrhea and progressive dyspnea. Acute respiratory distress syndrome (ARDS) due to bilateral pneumonia was diagnosed and he was also in septic shock. The patient had a history of partial hepatectomy for hepatoma, and suffered from liver cirrhosis. Emergency bronchoalveolar lavage (BAL) revealed abundant gram-positive cocci and polymorphonuclear leukocytes in the collected sample. Blood culture revealed corynebacterium. Treatment consisted of mechanical ventilation and administration of fluids, effective antibiotics, and high-dose methylprednisolone (MPS). MPS was administered from the onset of ARDS with a starting dose of 1,000 mg, which was gradually reduced to 60 mg over 8 days. Pulmonary infiltrates shown on the chest X-ray film were alleviated, and arterial blood gas data rapidly improved. The patient was successfully extubated on the 10th hospital day, and discharged on the 30th hospital day. Serial BAL and plasma levels of inflammatory cytokines decreased rapidly in parallel with the improvement of the patient's clinical condition. This is a case report of severe bacterial pneumonia that was successfully treated with effective antibiotics and high-dose MPS for several days from the onset of ARDS.     

Surface-acoustic-wave pulse transducer

Short pulses of surface acoustic waves are launched efficiently by an inline assembly of several finger-pair interdigital transducers, which are connected to successive taps of an electrical delay line, where the electrical time lag between two taps is equal to the acoustic delay between corresponding transducers.     

Indirekte polarographische Bestimmung von Kobalt

Zusammenfassung Es wurde eine Methode zur polarographischen Bestimmung von Co ausgearbeitet. Das Prinzip dieser Methode besteht in der Reaktion von Co^2÷ mit-Nitroso--Naphthol (N-N) im Natriumacetatmedium. Die Mengenabnahme des N-N, die eine Veränderung der Höhe der durch Reduktion von N-N auf der Hg-Tropfelektrode entstandenen polarographischen Welle hervorruft, ist der Konzentration von Co²⁺ der zu analysierenden Lösung direkt proportional. Die Reaktion findet unter gegebenen Bedingungen quantitativ im stöchiometrischen Verhältnis 3 Mol N-N zu I g-Atom Kobalt statt. Die ausgearbeitete Methode ist also sehr empfindlich, denn der Umsatz von I g-Atom Co ruft den Verlust von 3 Mol N-N hervor, was dem Verlust von 12 Elektronen bei der Reduktion auf der Hg-Tropfelektrode entspricht.Die störende Wirkung von Cu²⁺ wird durch Ausschütteln von Cu²⁺ in die Chloroformlösung von Bleidiäthyldithiocarbaminate aufgehoben; die Austauschreaktion Cu-Pb kann zur indirekten polarographischen Bestimmung von Cu auf Grund der Pb^2÷Reduktion ausgenutzt werden. Die stöde Wirkung des Eisens wird durch Zusatz von Sulfosalicylsäure aufgehoben.Die Methode ist bei der gegebenen Co-Konzentration (0,05-0,35 g/ml) ausreichend genau und empfindlich und scheint zur Co-Bestimmung in Lebensmitteln und natüchen Materialien besonders geeignet zu sein.

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Indirect polarographic determination of cobalt

Summary The method of indirect Polarographic determination of Co was elaborated. The reaction Co²⁺ with-nitroso--naphthol (N-N) in the medium of natrium acetate is the principle of this method. The decrease of concentration of N-N, that induces the change of the Polarographic wave created by reduction of N-N on Hg-dropelectrode, is proportional to the concentration of Co²⁺ in the analysed solution. The reaction is going under these experimental conditions in stoichiometric relation 3 moles of N-N to 1 g-atom Co. The elaborated method is very sensitive, because the reaction of 1 g-atom Co causes decrease of 3 moles N-N, what corresponds to the decrease of 12 electrones during reduction on Hg-electrode.The interfering Cu²⁺ are removed after extraction into the chloroform solution of Pb²⁺-diethyldithiocarbamate; it is possible to take use of the exchange reaction Cu-Pb for the indirect polarographic determination of Cu. The interfering Fe^3÷ are complexing with sulphosalicylic acid. The method is sufficiently precise and sensitive for this range of concentration (0.05 to 0.35 g Co/ml) and seems to be suitable for the determination of Co in foodstuffs and other natural materials.