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Wyszukujesz frazę "Bock, W." wg kryterium: Autor


Wyświetlanie 1-7 z 7
Tytuł:
Unique anatomy of lagomorph calcaneus
Autorzy:
Bleefeld, A R
Bock, W.J.
Powiązania:
https://bibliotekanauki.pl/articles/21813.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Lagomorpha
lagomorph calcaneus
mammal
calcaneus
anatomy
Opis:
The mammalian order Lagomorpha (hares, rabbits, pikas) comprises two families (Ochotonidae and Leporidae; McKenna and Bell 1998; Nowak 1999), and Recent members have a nearly world−wide distribution (Hoffman 1993; Nowak 1999). Detailed examination of the pedal morphology of extant and fossil lagomorphs revealed a unique channel (the “calcaneal canal”) running diagonally through the lagomorph calcaneus. The ancientness, ubiquity, and appearance of the calcaneal canal in all, including the earliest recognized lagomorph calcanea, and its absence from the pedes of other mammalian taxa, may indicate a long evolutionary separation of lagomorphs from other, previously suggested lagomorph relatives.
Źródło:
Acta Palaeontologica Polonica; 2002, 47, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Towards tuning of thermal sensitivity of the long period fiber gratings using a liquid crystal layer
Autorzy:
Czapla, A.
Bock, W.
Mikulic, P.
Woliński, T.
Powiązania:
https://bibliotekanauki.pl/articles/200642.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
long period fiber grating
liquid crystal
sensors
Opis:
A high-efficiency thermal tuning filter based on a long-period fiber grating (LPFG) combined with a low-birefringence liquid crystal (LB LC) cladding layer is presented. Two types of LPFGs were studied and compared: the LPFGs based on a standard telecommunication fiber produced by an electric arc technique, and the LPFGs based on a boron co-doped fiber written by a UV technique. Both types of LPFGs when enhanced with an external LB LC layer exhibit two different temperature sensitivities, which depend on the temperature range of operation. For the LPFGs based on standard telecommunication fiber we can conclude that the presence of the LB LC cladding increases the thermal tuning efficiency by more than one order of magnitude over the value for the LPFGs in air. In the case of the LPFGs based on the boron co-doped fiber we discovered it is possible to obtain either a temperature-independent attenuation band or the attenuation bands with high temperature sensitivities, just by careful choice of the order of the cladding mode and the operating wavelength.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2010, 58, 4; 503-508
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Novel Electrically Tunable Long-Period Fiber Grating Using a Liquid Crystal Cladding Layer
Autorzy:
Czapla, A.
Woliński, T.
Nowinowski-Kruszelnicki, E.
Bock, W.
Powiązania:
https://bibliotekanauki.pl/articles/1506728.pdf
Data publikacji:
2010-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.81.Cn
42.79.Dj
42.81.Pa
42.79.Kr
Opis:
The main aim of the presented work is the integration of a long-period fiber grating and a liquid crystal into a hybrid structure, in order to develop an innovative fiber optic device controlled by an external electric field. The studied long-period fiber grating was fabricated using UV irradiation in a boron co-doped fiber (PS1250/1500, manufactured by Fibercore). As a liquid crystal we used a typical 5CB nematic liquid crystal. The sensing mechanism of the proposed loss filter relies on long-period fiber grating attenuation bands sensitivity to optical properties of the liquid crystal layer. The results obtained show that the long-period fiber grating with a nanosized liquid crystal layer exhibits one order of magnitude higher electrical sensitivity and a lower level of the voltage control than the long-period fiber grating with a micro-sized liquid crystal layer.
Źródło:
Acta Physica Polonica A; 2010, 118, 6; 1104-1107
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature Cross-Sensitivity for Highly Refractive Index Sensitive Nanocoated Long-Period Gratings
Autorzy:
Grochowski, J.
Myśliwiec, M.
Mikulic, P.
Bock, W.
Śmietana, M.
Powiązania:
https://bibliotekanauki.pl/articles/1399344.pdf
Data publikacji:
2013-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Ce
42.79.Gn
07.07.Df
81.20.Fw
Opis:
There is a demand for highly refractive index sensitive devices simultaneously insensitive to temperature (T) changes. We investigate both T and refractive index sensitivity of long-period gratings coated with 100 nm thin high refractive index (n ≈ 1.9 at λ = 1550 nm) silicon nitride $(SiN_{x})$ film. The long-period gratings with period of 500 μm were induced in standard Corning SMF28 fibre using electric arc and nanocoated with $SiN_{x}$ by radio frequency plasma enhanced chemical vapour deposition method. As a sensorial effect we investigated resonance shift with temperature variations (from 30 to 70°C) for measurement in deionized water ($n_{D}$ = 1.33) and glycerine ($n_{D}$ = 1.46). In case of measurements in water for resonance observed at λ = 1510 nm, refractive index sensitivity of - 85 nm/RIU and temperature sensitivity of 0.09 nm/C $(H_2O)$ were obtained which gives refractive index-T sensitivity ratio (RI/T) of - 944°C/RIU. Refractive index and T sensitivity of sensor covered with $SiN_{x}$ film increased to - 618 nm/RIU and 0.22 nm/°C, respectively. Thanks to nanocoating deposition, refractive index-T sensitivity ratio was improved by factor of 3. In case of measurements in glycerine significant influence of glycerine's thermo-optic coefficient on obtained results was observed. It is worth noticing that $SiN_{x}$ coating stabilizes sensing behaviour of the sensor.
Źródło:
Acta Physica Polonica A; 2013, 124, 3; 421-424
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectral Tuning of the Long-Period Fiber Gratings by Using Low Birefringence Liquid Crystals
Autorzy:
Czapla, A.
Bock, W.
Woliński, T.
Dąbrowski, R.
Nowinowski-Kruszelnicki, E.
Powiązania:
https://bibliotekanauki.pl/articles/1493037.pdf
Data publikacji:
2011-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.81.Cn
42.79.Dj
42.81.Pa
42.79.Kr
Opis:
The work presented in this paper is focused on investigation of the spectral properties of the long-period fiber gratings combined with the liquid crystals, named liquid crystal long-period fiber gratings. The experiments carried out showed that the proposed designs of the liquid crystal long-period fiber gratings can offer very interesting spectral properties and can introduce a new level of sensitivity. In particular, a high-efficiency thermal tuning of the long-period fiber gratings coated with low-birefringence liquid crystal layers could be achieved and gave rise to a fast and wide switching ability of the attenuation bands within their transmission spectrum.
Źródło:
Acta Physica Polonica A; 2011, 120, 4; 589-592
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Wet Etching of Arc-Induced Long-Period Gratings on Their Refractive Index Sensitivity
Autorzy:
Myśliwiec, M.
Grochowski, J.
Krogulski, K.
Mikulic, P.
Bock, W.
Śmietana, M.
Powiązania:
https://bibliotekanauki.pl/articles/1399391.pdf
Data publikacji:
2013-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Ce
42.79.Gn
07.07.Df
81.20.Fw
Opis:
The paper presents highly refractive index sensitive operation of long-period gratings enhanced by wet etching of the fiber cladding. Long-period gratings with period of 283 μm were induced in Corning SMF28 optical fibre using electric arc technique. Then etching in hydrofluoric (HF) acid solution has been applied to improve operation of the sensor. Sensitivity improvement effect induced by fiber cladding reduction has been numerically simulated. The developed numerical model enables quick estimation of cladding thickness reduction essential to achieve dispersion turning point. At this point long-period gratings reaches maximum sensitivity to external medium refractive index. Simulation showed that dispersion turning point for this long-period grating is achieved by cladding thickness reduction of 1.7 μm. We obtained good simulation match with experimental results, where approximately the same thickness was etched. The refractive index sensitivity of the long-period grating-based sensor has been improved by factor of 5. Since long-period grating period is limited when using electric arc fabrication method, this physical limitation makes difficult achievement of dispersion turning point and reaching maximum sensitivity of the long-period grating. We show that sensitivity of electric arc induced long-period grating can be significantly improved by post processing techniques such as wet etching.
Źródło:
Acta Physica Polonica A; 2013, 124, 3; 521-524
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Długookresowe siatki światłowodowe jako czujniki drgań w materiałach kompozytowych
Long period fiber gratings as vibration sensors in composite materials
Autorzy:
Domański, A. W.
Czapla, A.
Prokopczuk, K.
Poczęsny, T.
Bock, W.
Woliński, T. R.
Powiązania:
https://bibliotekanauki.pl/articles/154785.pdf
Data publikacji:
2010
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
światłowodowe siatki długookresowe
światłowód
czujnik
drgania
naprężenia
materiały kompozytowe
long period fiber gratings
optical fiber
sensor
vibration
stress
composite materials
Opis:
Użycie czujników opartych na siatkach LPFG otwiera nowe możliwości diagnostyczno-pomiarowe, takie jak na przykład monitorowanie w czasie rzeczywistym stanu zużycia materiałów kompozytowych. Dzięki zatopieniu włókna w takim materiale możliwe jest monitorowanie drgań i naprężeń nie powodując przy tym znaczących zmian parametrów eksploatacyjnych i wytrzymałościowych kompozytu. W prezentowanej pracy przedstawiono zastosowanie siatek LPFG do detekcji deformacji geometrycznych oraz przeprowadzono badania porównawcze czujników światłowodowych z siatkami LPFG zatopionych w materiale kompozytowym z tego samego typu czujnikami pracującymi w swobodnej przestrzeni.
Vigorously growing fiber-optic technology allows constructing sophisticated sensors to monitor vibrations and stress. Application of long period fiber gratings (LPFG) enables making an optical fiber sensitive to various external parameters caused by longitudinal or transverse stress changes in material. An additional advantage of sensors based on LPFG is the measuring part insensitivity to electromagnetic disturbance and lack of electric noise and interference emission. The manufacturing of optical fiber with LPFG is based on precise heating or exposition a part of the fiber to ultraviolet radiation thereby inducing a periodic change of the refraction index along the fiber core. As a result, the transmission spectrum of LPFG is characterized by a number of attenuation bands induced by coupling between the elementary mode propagating in the core and cladding modes. Location of the attenuation bands in the LPFGs transmission spectrum is dependent on external physical factors. This paper presents application of LPFG to geometric deformation detection. The use of sensors based on LPFG opens new diagnostic and measuring possibilities like real-time monitoring of composite material wear. Due to sinking the LPFGs in this material, it is possible to monitor the vibrations and stresses without causing significant changes in operational performance and durability of the composite. The paper also presents a comparative study on LPFGs sunk in composite material with the same type of LPFGs operating in free space.
Źródło:
Pomiary Automatyka Kontrola; 2010, R. 56, nr 7, 7; 809-811
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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