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This paper reports a study of the sorption properties of thin Ta 2 O 5 films to NH 3 vapors. The films are deposited using electron beam evaporation. In order to determine the sorption ability of Ta 2 O 5 to NH 3 , a quartz crystal microbalance (QCM) with a thin Ta 2 O 5 film is investigated. The Ta 2 O 5 film is used as a receptor for the NH 3 gas. The AT-cut, 14 MHz quartz resonators allow conversion of the additional mass loading that occurs as a result of sorption into a frequency shift. The experiments are carried out by measuring the resonant frequency shift of the QCM to vapors from an aqueous solution of NH 3 with different concentrations from 10 to 10 000 ppm. The obtained experimental results indicate that the variations of the resonant frequency are a function of the ammonia concentration and the thickness of the Ta 2 O 5 layer. The process of sorption is found to be reversible. The reported investigation shows that a QCM covered with a thin Ta 2 O 5 layer is sensitive to ammonia vapors at room temperature and is able to detect NH 3 concentrations in the investigated range (10-10000 ppm).

Ta2O5 is a material with good perspectives for many applications in modern electronics and information technologies. Several deposition techniques of thin Ta2O5 films have been suggested. Reliable information is still needed, however, on structural, electrical and optical parameters of the films, and their dependence on the deposition technique. We have deposited Ta2O5 thin films by electron-beam evaporation of Ta2O5 powder onto Si, tantalum and glass substrates. The resistivity of the films with various thicknesses was measured by four-point probe method before and after annealing in an oxygen atmosphere. The reflectance in the IR region depending on the substrate and film thickness was shown. 14th Biannual International Summer School on Vacuum, Electron and Ion Technologies, Sep 12-16, 2005, Burgas, Bulgaria

Aim: To present the results from one clinic’s experience of using small intestinal submucosa (SIS) in augmentation urethroplasty for management of strictures of the bulbar urethra. Methods: Urethral surgery was performed in nine men with strictures 4–6 cm. All of the patients were evaluated by history, physical examination, retrograde urethrogram, and uroflowmetry. Four layers of SIS were soaked in saline or Ringer’s solution for 15 minutes at 37°C, and the inner surface of the patch was gently fenestrated with a thin scalpel. The patch was spread-fixed onto the tunica albuginea. The mucosa was sutured to the submucosal graft first at 2–3 mm inwards from the SIS margins, then the spongiosum tissue was attached to the margins with interrupted absorbable sutures. Results: Of the nine patients who underwent augmentation urethroplasty using SIS, only one had re-stricture at 6 months due to urethral infection. At 18 months after the surgery the uroflowmetry of the other eight patients was 20–21 mL/s. In terms of complications, six patients reported having post-micturition dribbling, and seven patients reported lack of morning erections for 35–69 days after surgery. Conclusions: Using SIS is a safe procedure; however, long-term follow-up is needed to substantiate the good short-term results.