Wyniki wyszukiwania - Biblioteka Nauki

1

A stack multilayer high reflectance optical filter produced on polyester substrate with the PECVD technique

100%

Kowalski J. , Szymanowski H. , Sobczyk-Guzenda A. , Gazicki-Lipman M.

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2009

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tom Vol. 57, nr 2

171-176

EN

The present work reports results of an effort to produce a stack multilayer optical filter on a poly(ethylene terephtalate) (PET) substrate, using a PECVD technique. Titanium dioxide type of material (n550 = 2.3) has been selected for high refractive index layers while that of silicon dioxide type (n550 = 1.4) served as low refractive index films. For a synthesis of the former material, titanium tetrachloride with an excess of gaseous oxygen was taken as a precursor system, and a mixture of oxygen and hexamethyldisiloxane (HMDSO) was used as a precur-sor system for a deposition of the latter one. The entire deposition process was carried out in the same parallel plate PECVD reactor, with all the consecutive layers being synthesized in one vacuum run. In the first part of the work, the deposition processes of both types of materials were optimized separately using polyester film as a substrate. The main goal of this step was to obtain high refractive index and low refractive index materials of good optical quality, remaining as close as possible to that of, respectively, titanium dioxide and silicon dioxide, without jeopardizing the optical quality of the polymer support. A construction of the filter was the next stage of the work. The design concerned high reflectance (HR) type filter consisting of five high refractive index layers, separated by four low refractive index films. Before an actual deposition, a performance of such system had been simulated, using the TFCalcTM 3.5 optical software. As a final step, the real structure, consisting of nine films, was produced, and the optical properties of the so obtained filter have been compared with those of the simulated system.

2

Acoustic spectroscopy and electrical characterization of SiO2/Si structures with ultrathin SiO2 layers formed by nitric acid oxidation

88%

Bury P. , Kobayashi H. , Takahashi M. , Imamura K. , Sidor P. , ÄŒernobila F. e.

Open Physics

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2009

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tom 7

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nr 2

237-241

EN

Ultrathin silicon dioxide (SiO2) layers formed on Si substrate with nitric acid have been investigated using both acoustic deep-level transient spectroscopy (A-DLTS) and electrical methods to characterize the interface states. The set of SiO2/Si structures formed in different conditions (reaction time, concentrations of nitric acid (HNO3), and SiO2 thickness [3â€“9 nm]) was prepared. The leakage current density was decreased by post-oxidation annealing (POA) treatment at 250Â°C in pure nitrogen for 1 h and/or post-metallization annealing (PMA) treatment at 250Â°C in a hydrogen atmosphere for 1 h. All structures of the set, except electrical investigation, current-voltage (I - V), and capacitance â€” voltage (C - V) measurements, were investigated using A-DLTS to find both the interface states distribution and the role of POA and/or PMA treatment on the interface-state occurrence and distribution. The evident decreases of interface states and shift of their activation energies in the structures with PMA treatment in comparison with POA treatment were observed in most of the investigated structures. The results are analyzed and discussed.

3

Copolymerization of ethylene with 1-hexene over supported zirconocene catalysts

63%

Echevskaya L. G. , Zakharow V. A. , Semikolenowa N. V. , Mikenas T. B.

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2001

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tom T. 46, nr 1

40-43

EN

Two supported zirconocene catalysts were prepared: (I) SiO2/MAO/Me2Si(Ind)2ZrCl2 (0.1 wt. % Zr, 9.0 wt. % Al) and (II) MgCl2/Me2Si(Ind)2ZrCl2 (0.2 wt. % Zr, 1.6 wt. % Al). Ethylene was homopolymerized and copolymerized with 1-hexene (70-90°C, 6 bar, TIB A as cocatalyst) over (I) and (II). Catalyst (I) incorporated the comonomer as much as did the homogeneous catalyst of the same composition. MgCl2 used as support resulted in reduced copolymerization reactivity of the catalyst. Copolymer crystallinity and catalyst activity were studied in relation to the concentration of 1-hexene.

PL

Zbadano przebieg procesów homopolimeryzacji etylenu i kopolimeryzacji etylenu z 1-heksenem wobec układów katalitycznych SiO2/MAO/Me2Si(Ind)2ZrCl2 + TIBA (układ I, gdzie MAO = metyloaluminoksan, Ind = indenyl, TIBA = triizobu-tyloglin) oraz MgCl2/Me2Si(Ind)2ZrCl2 + MAO (układ II) w temp. 70-90°C (tabele 1-3, rys. 1 i 2). Wprowadzenie 1-heksenu jako komonomeru znacznie zwiększa katalityczną aktywność układu I oraz zmniejsza stopień krystaliczności produktu. Wzrost stężenia 1-heksenu w kopolimeryzacji wobec układu II powoduje zmniejszenie aktywności katalizatora. Określono też wpływ rodzaju nośnika (SiO2 lub MgCl2) na współczynnik reaktywności etylenu (r1) w kopolimeryzacji (tabela 4); jest on większy w przypadku zastosowania MgCl2.

4

Jonitowe odkrzemianie wody kotłowej

63%

Kaleta J.

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2003

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tom z. 35 [204]

107-113

PL

Krzemionkę usuwano z wody, stosując następujący układ technologiczny: kationit silnie kwaśny + anionit słabo zasadowy + anionit silnie zasadowy. Efektywność zastosowanych procesów była bardzo duża; krzemionkę usuwano do ilości śladowych. Zdolność wymienna kationitu silnie kwaśnego wyniosła 4,5 mval/g, natomiast zdolność wymienna anionitu silnie zasadowego w odniesieniu do krzemionki wyniosła 0,6 mval/g. Oczyszczona w ten sposób woda odpowiada wymaganiom stawianym kotłom wysokoprężnym.

EN

Silicon dioxide is removed from water using the following technological configuration: strongly acidic cation exchanger + weakly basie anion exchanger + strongly basie anion exchanger. The effectiveness of the employed process was very high; silicon dioxide was redu-ced to trace amounts. The exchange capacity of the strongly acidic cation exchanger was 4,5 mval/dm3, while the exchange capacity of the strongly basie anion exchanger with respect to silicon dioxide was 0,6 mval/dm3. Water purified in this manner fulfills the stated reąuirements for supply to high-pressure boilers.