We demonstrate Q-switched pulse generation in thulium-doped fiber lasers by introducing piezoelectric-driven microbend with preloaded stress. We employed a pair of corrugated chips each attached on ...piezoelectric actuators (PAs) to clamp the fiber in a ring laser resonator. The thulium-doped fiber is pumped by a laser diode emitting at 1.63 μm and generates the Q-switched laser pulses at around 1.9 μm by switching off the PAs. The laser pulse performance is improved by optimizing the preload and switch-off period for the PAs. The Q-switched pulses with a peak power of 2.8 W and a pulsewidth of 900 ns are observed for a launched pump power of 161 mW. We expect that the in-fiber Q-switching technique will provide efficient laser systems for environmental sensing and medical applications.
The d.c. electrical conductivity and optical properties of undoped zinc oxide films prepared by the sol-gel process using a spin-coating technique were investigated. The ZnO films were obtained by 10 ...cycle spin-coated and dried zinc acetate films followed by annealing in air at 500–575°C. The films deposited on the Pyrex glass substrate were polycrystalline and
c-axis oriented. A minimum film resistivity gave 28.2 Ω cm at an annealing temperature of 525°C. The temperature dependence of the conductivity indicated electron transport in the conduction band due to thermal excitation of donor electrons for temperatures from 250 to 300 K. The grain boundary scattering effect due to thermionic emission was confirmed. For temperatures below 250 K nearest-neighbor hopping conduction was dominant in the films. The films were transparent in the visible range above 400 nm and had sharp ultraviolet absorption edges at 380 nm. The absorption edge analysis revealed that the optical band gap energy for the films was 3.20–3.21 eV and the electronic transition was of the direct transition type. From the Urbach tail analysis the width of the localized state
E
e
=0.07–0.08 eV.
We report the single crystal growth and superconducting transition of a misfit layered compound (SbS)1.16TaS2. We succeed in the single crystal growth with flux method. The electrical resistivity ...measurements revealed the superconducting transition temperature of this material as 2.9 K, which was consistent with the previous research. Scanning tunneling microscopy measurements show two kinds of surfaces corresponding to TaS2 and SbS layers, indicating successful growth of the single crystal consist of stacking of these layers.
Transition metal dichalcogenides 2H-TaS2 and 2H-TaSe2 show charge density wave (CDW) state and superconductivity. It has been reported that elemental substitution of chalcogenide suppresses the CDW ...and enhances superconductivity. However, how the CDW order is suppressed by the substitution has not been clarified yet. To clarify this, we performed real space observation of the CDW state in the commensurate phase of 2H-TaS1.8Se0.2 by scanning tunneling microscopy. The existence of domains separated by walls at which the phase of the CDW shifts was observed. The change in the electronic state on the domain boundaries in 2H-TaS1.8Se0.2 was not as drastic as that in 1T-FexTa1-xS2.
Undoped ZnO films were post-annealed in hydrogen at 350°C for 3h after sol–gel spin-coating film fabrication followed by annealing from 500 to 575°C, and their electrical and optical properties were ...investigated. The post-annealed films indicated c-axis oriented polycrystalline zinc oxide including metallic zinc as interstitial atom in the lattice as well as those before H2 annealing. The films were n-type semiconductors. The minimum resistivity of the films was 0.22Ωcm. Donor levels for the films Ed=0.04–0.08eV were estimated from the temperature dependence of the conductivity above 250K. The conduction mechanism of the post-annealed ZnO films was shifted from band conduction including ionized impurity scattering and grain boundary scattering at temperatures between 250 and 300K to variable-range hopping conduction below 250K. The films were transparent in the visible range above 400nm and had sharp ultraviolet absorption edges at 380nm. The optical band gap energy was evaluated to be Eopt=3.20–3.21eV, and the width of the localized state Ee was obtained to be Ee=0.08–0.09eV from the Urbach tail analysis.
The passively Q-switched operation of all-fibre thulium fibre lasers using UV-curing resin doped with multi-walled carbon nanotubes as a saturable absorber is demonstrated. A single-mode ...thulium-doped silica fibre is pumped by a laser diode emitting at 1.63 µm through a wavelength-division multiplexing coupler. Unidirectional laser output from the fibre ring resonator is attained by using the retroreflector at the counter-directional output port. The fibre laser exhibits 1.9 µm wavelength pulsed oscillation at a repetition rate of 7.2 kHz. When the pump power is increased to 161 mW, the output pulse power is measured by 150 mW with a pulse width of 3.2 µs.
Summary
Background
Idiopathic mesenteric phlebosclerosis (IMP) is a rare disease, characterised by thickening of the wall of the right hemicolon with calcification of mesenteric veins. However, the ...aetiology remains unknown.
Aim
To investigate the possible association of herbal medicines with IMP.
Method
The clinical data of four of our own patients were collected. Furthermore, we searched for previous reports about similar patients with detailed descriptions of herbal prescriptions that they had taken. We compared herbal ingredients to identify the toxic agent as a possible aetiological factor.
Results
Clinical data on a total of 25 patients were summarised. Mean age was 61.8 years and there was female predominance (6 men and 19 women). The used Kampo prescription, the number of cases, and the mean duration of use were as follows: kamisyoyosan in 12 cases for 12.8 years, inshin‐iseihaito in 5 cases for 13.4 years, orengedokuto in 4 cases for 14.3 years, inchinkoto in 1 case for 20 years, kamikihitou in 1 case for 19 years, seijobofuto in 1 case for 10 years and gorinsan in 1 case for an unknown duration. Only one ingredient, sansisi, was common to the herbal medicines of all 25 patients. This crude drug called geniposide in English is a major constituent of the Gardenia fruits.
Conclusion
The long‐term use of geniposide in herbal medicines appears to be associated with mesenteric phlebosclerosis.
Aims: To evaluate the efficacy of insulating the limbs and thorax of cats with a combination of bubble wrap and an absorbent, plastic-lined pad in reducing heat loss during ovariohysterectomy.
...Methods: A preliminary study was performed to compare heat loss of 1 L bags of Hartmann's solution heated to 38°C which were either wrapped in two layers of bubble wrap and an absorbent pad (n = 6) or were unwrapped (n = 6). Bags were allowed to cool in a temperature-controlled room and the temperature of the bags was measured every 10 minutes for 60 minutes. The clinical study, included 16 intact female cats undergoing ovariohysterectomy. The cats were premedicated with I/M morphine and either medetomidine or dexmedetomidine, and anaesthesia was induced with I/V propofol and maintained with isoflurane in 100% oxygen. Cats were randomly assigned to either the treatment group (n = 8) whose limbs and thorax wrapped with two layers of bubble wrap and an absorbent pad immediately after induction, or the control group (n = 8) which were unwrapped. Body temperature (measured with an oesophageal temperature probe), heart rate, respiratory rate, mean arterial pressure and partial pressure of end-tidal CO
2
were recorded immediately after induction (T
start
), before surgery started (T
surgery
), and at the end of isoflurane administration (T
end
). The times from T
end
to extubation, from T
end
to when the cat could maintain sternal recumbency and from T
end
to when the cat was able to stand, were also recorded.
Results: In the preliminary study of heat loss by fluid bags, the mean temperature at 60 minutes was higher in wrapped bags (35.4 (SD 0.2)°C) compared to unwrapped bags (33.0 (SD 0.3)°C; p < 0.01). For cats undergoing ovariohysterectomy, mean body temperature of wrapped cats was higher than that of unwrapped cats both at T
surgery
(36.0 (SE 0.3) vs. 34.5 (SE 0.3)°C; p = 0.001) and at T
end
(37.2 (SE 0.5) vs. 36.0 (SE 0.5)°C; p = 0.01). Wrapped cats regained the ability to stand more rapidly that unwrapped cats (26.4 (SE 5.8) vs. 47.0 (SE 5.8) minutes p = 0.01).
Conclusions: Wrapping the limbs and thorax of cats undergoing ovariohysterectomy in a combination of bubble wrap and absorbent pads reduced heat loss, which in turn improved recovery time from general anaesthesia.
Clinical relevance: This inexpensive and practical method may reduce perioperative hypothermia, in cats undergoing abdominal surgery.
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