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1.
Seetharam Shettigar G. Umesh K. Chandrasekharan Ganesh Rai B. Kalluraya 《应用聚合物科学杂志》2008,108(5):3218-3224
We report the measurements of the third-order susceptibilities and two-photon absorption in three different polymers doped with p-phenyl sydnone moiety viz., 2-benzylhydrazono-5-(3-p-tolylsydnone-4-yl)1,3,4,-thiadiazine, which is recently synthesized and characterized, with the prospective of reaching a good compromise between processability and high nonlinear optical properties. The measurements were done using nano second Z-scan at 532nm. The Z-scan spectra reveal a large negative nonlinear refraction coefficient n2 of the order 10−14 cm2/W and a two-photon absorption β, which is determined to be the order of cm/GW. The absorption cross section is 10−46 cm4 s/photon. The molecular second-order hyperpolarizability in PMMA matrix was calculated to be 1.47 × 10−31 esu, comparable with stilbazolieum derivatives, a well-known class of optical materials for photonics and biophotonics applications. The chromophore shows its optical power limiting behavior in all the three polymer matrices. All these results suggest that this moiety has potential for the application of all-optical limiting and switching devices. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
2.
Gordon McKay 《American Institute of Chemical Engineers》1984,30(4):692-697
An analytical solution for a two resistance mass transfer model explaining the adsorption of Astrazone Blue dye (Basic Blue 69) onto Sorbsil silica has been developed. The model includes a film mass transfer coefficient, kf1 = 80 × 10−6cm·s−1, and an internal effective diffusivity, Deff = 18×10−9cm2·s−1 which controls the internal mass transport processes based on a pore diffusion mechanism. 相似文献
3.
Silylated poly(4-hydroxystyrene)s and radical polymerized 4-tert-butyldimethylsilyloxystyrene (TBDMSOSt) were examined as electron beam resists. Commercial poly(4-hydroxystyrene) (PHS) with Mw = 1.69 × 104 and Mw/Mn = 5.41 was silylated with 1-(trimethylsilyl)imidazole and tert-butylchlorodimethylsilane. Both silylation reactions proceeded quantitatively to afford trimethylsilylated PHS with Mw = 3.93 × 104 and Mw/Mn = 4.91, and tert-butyldimethylsilylated PHS with Mw = 4.08 × 104 and Mw/Mn = 3.81. These 2 silyl ether polymers acted as a negative working resist to electron beam (EB) exposure. Sensitivity and contrast of tert- butyldimethylsilylated PHS were not affected by prebake temperature around its Tg of 97°C, while those of PHS were dependent on prebake temperature around its Tg of 160°C. At a prebake temperature of 125°C, the sensitivity parameter and the contrast γ value were obtained as follows: 3.93 × 10−4 C cm−2 and 0.91 for PHS; 1.49 × 10−4 C cm−2 and 1.06 for trimethylsilylated PHS; 1.84 × 10−4 C cm−2 and 1.44 for tert-butyldimethylsilylated PHS. The silylation procedures obviously improved the sensitivity of PHS. TBDMSOSt was polymerized in bulk at 60°C with 2,2′-azobisisobutyronitrile (AIBN) as an initiator. The resultant poly(TBDMSOSt) possessed Mw = 3.01 × 105 and Mw/Mn = 1.92 and exhibited a sensitivity of 1.60 × 10−5 C cm−2 and a γ value of 1.47. More than 10 times enhancement of sensitivity was observed compared with tert-butyldimethylsilylated PHS. Such a high sensitivity is probably due to the high molecular weight of the bulk polymerized material. Poly(TBDMSOSt) resolved an isolated line of 0.20 μm width and 0.5 μm line and space patterns. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 1151–1157, 1998 相似文献
4.
A new polymeric Ag(I) complex {[Ag2(pbbt)3](NO3)2·0.5H2O}n [where pbbt = 1,1′-(1,3-propylene)-bis-1H-benzotriazole] was synthesized as a good optical limiter. Single-crystal X-ray diffraction determined that the complex assumed a rare, two-dimensional lamellar structural motif with isolated cavities of [Ag6(pbbt)6]. The Z-scan measurements of an 8-ns pulsed laser at 532 nm revealed that the presented complex in dimethylformamide exhibited very strong third-order optical nonlinear absorption. The optical-limiting (OL) performance was investigated in the sample of the complex induced by 8-ns and 30-ps pulses at 532 nm. The results show that this complex exhibited large OL effects with a very low limiting threshold value of 0.16 J/cm2 under 8-ns pulse and 0.56 J/cm2 under 30-ps pulses, among those of the best OL materials. Density functional theory calculation results further confirmed the cooperative contributions of Ag ions and bridge ligands to the optical nonlinearities of Ag(I)-containing metal–organic complex. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
5.
The nonlinear optical properties of an azobenzene‐containing ionic liquid crystalline polymer were investigated using single‐beam Z‐scan and optical Kerr effect (OKE). The polymer film exhibited large nonlinear absorption (~10?6 cm W?1) and nonlinear refraction (~10?11 cm2 W?1) under 532 nm ps excitation. The femtosecond time‐resolved OKE results suggested that the nonlinear optical response time in off‐resonant region was as fast as 300 fs. Moreover, stable molecular reorientation and a large photoinduced birefringence ( ) were achieved in the polymer film with a 405 nm continous wave (CW) laser as pump light. The large optical nonlinearity, ultrafast response, and effective photoinduced molecular reorientation of the polymer films indicated their potential applications in nonlinear photonic devices and optical storage. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
6.
《Gas Separation & Purification》1991,5(1):11-15
The effective diffusivities of carbon dioxide through the Tiva Canyon tuff and the lower lithophysal zone of the Topopah Spring tuff (outcrop samples of the layer above the proposed nuclear repository site layer) were determined using a steady-state method (counter diffusion). The diffusivity of carbon dioxide through the Tiva Canyon and lithopysal zone tuffs increased with temperature. The following correlation was obtained to estimate the effective diffusivity of carbon dioxide through the Tiva Canyon tuff in cm2 s−1 as a function of temperature (K). De = 1.22 × 10−2 − 3.77 × 10−5T + 9.95 × 10−8T2The effective diffusivity of carbon dioxide through the lower lithophysal zone of the Topopah Spring tuff (layer right above the proposed repository site) also increased with temperature. For this layer, the following correlation was obtained to estimate the effective diffusivity of carbon dioxide in cm2 s−1 as a function of temperature (K). De = − 1.11 × 10−3 + 1.25 × 10−5T + 1.83 × 10−9T2 相似文献
7.
S. Vijayakumar Adithya Adhikari Balakrishna Kalluraya K. N. Sharafudeen K. Chandrasekharan 《应用聚合物科学杂志》2011,119(1):595-601
We investigated the third‐order nonlinear optical properties of donor–acceptor substituted hydrazones doped into PMMA matrix using single beam Z‐scan technique at 532 nm. The magnitude of third‐order susceptibility, χ(3) is of the order of 10−13esu. The nonlinear refractive index, n2 and the molecular second order hyperpolarisability, γh are of the order of 10−11esu and 10−32esu, respectively. The compounds exhibit larger third‐order NLO properties in PMMA host when compared to the pure compounds. The study reveals that these hydrazones are a good candidate of nonlinear optical materials for photonic applications. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
8.
Louis J. Kirschenbaum Edward T. Borish James D. Rush 《Israel journal of chemistry》1985,25(2):159-163
Kinetic and stoichiometric data are reported for the reduction of Ag(OH)−4 with Fe(CN)4−6, MnO2−4 and Mo(CN)4−8. The rate constants for reduction to Ag(II) are 1.1 × 105 M−1 s−1, 1.3 × 104 M−1 s−1 and < 1 × 102 M−1 s−1, respectively, at 25°C and μ = 1.2 M. Reaction with Mo(CN)4−8 results in an apparent one-electron equilibrium, indicating a Ag(OH)−4/[Ag(II)]n potential near that of the Mo(V)/MO(IV) couple. In the Fe(CN)4−6 and MnO2−4 reactions, there is a competition between transfer of a second electron to silver and polymerization of silver(II). A general mechanism for these reactions is presented. 相似文献
9.
A series of iron‐based perovskite oxides BaFe1−xCuxO3−δ (x = 0.10, 0.15, 0.20 and 0.25, abbreviated as BFC‐10, BFC‐15, BFC‐20 and BFC‐25, respectively) as cathode materials have been prepared via a combined EDTA‐citrate complexing sol‐gel method. The effects of Cu contents on the crystal structure, chemical stability, electrical conductivity, thermal expansion coefficient (TEC) and electrochemical properties of BFC‐x materials have been studied. All the BFC‐x samples exhibit the cubic phase with a space group Pm3m (221). The electrical conductivity decreases with increasing Cu content. The maximum electrical conductivity is 60.9 ± 0.9 S cm−1 for BFC‐20 at 600 °C. Substitution of Fe by Cu increases the thermal expansion coefficient. The average TEC increases from 20.6 × 10−6 K−1 for BFC‐10 to 23.7 × 10−6 K−1 for BFC‐25 at the temperature range of 30–850 °C. Among the samples, BFC‐20 shows the best electrochemical performance. The area specific resistance (ASR) of BFC‐20 on SDC electrolyte is 0.014 Ω cm2 at 800 °C. The single fuel cell with the configguration of BFC‐20/SDC/NiO‐SDC delivers the highest power density of 0.57 W cm−2 at 800 °C. The favorable electrochemical activities can be attributed to the cubic lattice structure and the high oxygen vacancy concentration caused by Cu doping. 相似文献
10.
Kimiaki Tsutsui Hiroaki Yoshimizu Yoshiharu Tsujita Takatoshi Kinoshita 《应用聚合物科学杂志》1999,73(13):2733-2738
The permeability coefficients of O2, N2, and CO2 gases at 25°C were examined for composite membranes that were prepared by filling poly(ethylene oxide)(PEO) with different molecular weights into a porous membrane. The permeability coefficients of O2, N2, and CO2 were 2 × 10−10 – 4 × 10−10, 5 × 10−11 – 9.5 × 10−11, and 6 × 10−10 – 1 × 10−9 (cm3 STPcm/cm2 s cmHg), respectively. The higher permeability coefficients of CO2 are explained in terms of high solubility of CO2 in filled PEO. The permeability coefficient of CO2 was affected by the degree of crystallinity of PEO in the composite. On the other hand, there was little effect of crystallinity on O2 and N2 permeability coefficients. Some probable relationships between selectivities of O2 to N2 and CO2 to N2 and the degree of crystallinity of PEO were observed. The CO2 gas permeability coefficients of the composite membrane for PEO50000 (Mw = 5 × 104) showed a marked change due to melting or crystallization of PEO. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2733–2738, 1999 相似文献
11.
The technique of simultaneous pulse radiolysis and photolysis, PRAP, has been utilized to study the reactions of various radicals with ground state ZnTPPS and the triplet state ZnTPPST in aqueous solutions. The radicals H and OH add to both states with k ∼ 1 × 1010 M−1 s−1. The CH2C(CH3)2OH radical from t-BuOH is relatively inert toward ZnTPPS but reacts rapidly (k = 1.8 × 109 M−1 s−1) with ZnTPPST to form an adduct. Electron transfer reactions are found to be about an order of magnitude faster with the triplet than with the ground state. The (CH3)2COH radical reduces both ZnTPPS (k = 1 × 108 M−1 s−1) and ZnTPPST (k = 3 × 109 M−1 s−1) to the anion radical (ZnTPPS)−. The radical Br−2 oxidizes both states to the cation radical (ZnTPPS)+ with k = 8 × 108 M−1 s−1 for the ground state and 5 × 109 M−1 s−1 for the triplet. The transient cation Cd+ reduces both states with a diffusion-controlled rate (k = 1 × 1010 M−1 s−1) to produce the anion radical. The above mechanisms of radical addition and electron transfer are also supported by the product spectra. 相似文献
12.
Alkylsilane-modified styrene-butadiene-styrene (SBS) polymers were prepared via two steps. In the first step, dimethylchlorosilane HSi(CH3)2Cl and SBS (Korea Kumho Petrochem. Co.; 35% vinyl content; Mo = 48,000, Mo/Mn = 1.05) were reacted in toluene using H2PtCl6 catalyst to produce a hydrosilylated polymer. In the second step, chloride in the silyl group was replaced with alkyl by reaction with RLi (R = Me, n-Bu). Under severe conditions, silylation occurs on all the double bonds of the polymer so that their elastomeric nature disappears. However, under mild conditions, selective hydrosilylation of the pendant vinyl groups of SBS could be accomplished so that the polymer retained its elastomeric properties with two low Tg values. These modified SBS polymers were easily dissolved in THF, and thus could be formed into film-type membranes by solvent casting on teflon plates. From the measurements of their gas permeability for O2 and N2, they showed higher selectivity for O2 compared with the unmodified SBS. The permeability for oxygen was dependent on the size of the alkylsilyl group. Methylsilane and butylsilane-modified SBS membranes showed the higher permeability values of 31.2 and 37.5 barrer (1 barrer = 1 × 10−10 cm3 (STP) cm cm−2 s−1 cmHg−1) at 30°C, respectively, compared with 2.39 barrer of the unmodified SBS. Furthermore, their selectivities for O2 over N2 were increased to 3.0 and 3.2, respectively, from 2.5 of the unmodified SBS case. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1117–1122, 1997 相似文献
13.
This article reports experimental work on the effect of N+ ion implantation on third‐order nonlinear optical properties of POT films. Using K2Cr2O7 as oxidizing agent, poly‐ortho‐toluidine (POT) was synthesized in 1 M hydrochloric. The POT films were prepared by spin‐coating method and then implantated by N+ ions (15–30 KeV) at a dose 1.9 × 1016 ions/cm2. The films were characterized by FT‐IR spectroscopy, visible spectroscopy and SEM, their third‐order nonlinear optical susceptibility (χ(3)) were also examined by a degenerate four‐wave mixing (DFWM) system at 532nm. Compared to pristine POT films, the optical band gap obtained from visible spectra decreased from 3.58 to 3.48 eV when the energy was 30 KeV. Also, The χ(3) value of implantated POT films increased from 3.31 × 10−10 esu to 4.04 × 10−9 esu when the implantated energy was 25 KeV. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers 相似文献
14.
Lenka Belh
ov Josef Krýsa Josef Geryk Jaromír Jirkovský 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1999,74(2):149-154
A laboratory flow‐through photoreactor with an immobilized layer of TiO2 (total volume of the liquid 5000 cm 3, photoactive area 60 cm long and 30 cm wide; irradiation source UV lamps Eversun, Osram, light intensity from 0.9 to 6.2×10−9 Einstein cm−2 s −1) was tested for the inactivation of Escherichia coli (strain DH5α) and bacteriophage λNM1149. The kinetics of the deactivation were approximately first order and the initial reaction rate depended on the light intensity. At maximum intensity, the rate constants of the bacteria and viruses inactivation were 2.3×10−4 and 7.2×10−4 s−1, respectively. Bacterial inactivation was also accomplished with solar excitation. © 1999 Society of Chemical Industry 相似文献
15.
Nafion® membrane blended with polyacrylonitrile nanofibers decorated with ZrO2 was successfully fabricated. The composite membrane showed improved proton conductivity, swelling ratio, thermal and mechanical stability, reduced methanol crossover, and enhanced fuel cell efficiency. The nanocomposite membranes achieved a reduced methanol crossover of 5.465 × 10−8 cm2 S−1 compared to 9.118 × 10−7 cm2 S−1 of recast Nafion® membrane using a 5 M methanol solution at 80°C. The composite membrane also showed an ion conductivity of 1.84 compared to 0.25 S cm−1 recast Nafion® at 25°C. The composite membranes showed a peak power density of 68.7 mW·cm−2 at 25°C, these results show a promising composite membrane for fuel cell application. 相似文献
16.
Anjana Jain 《Polymer Engineering and Science》2008,48(2):211-215
The effect of in situ heating on the unit cell dimensions of crystalline aramid fiber (Twaron® fibers) has been studied in the temperature range 20–280°C. The changes in the unit cell dimensions have been used to estimate the coefficients of thermal expansion along the axial directions. On heating, the a and b axes expand, the coefficients of thermal expansion being αa = 35.84 × 10−6/°C and αb = 38 × 10−6/°C at room temperature. The c-axis contracts on heating, giving negative coefficient of thermal expansion αc = −5.38 × 10−6/°C at room temperature. Volume coefficient of thermal expansion αV however is positive, being 101.22 × 10−6/°C. POLYM. ENG. SCI., 2008. © 2007 Society of Plastics Engineers 相似文献
17.
John Eckelt Anja Knopf Thomas Röder Hedda K. Weber Herbert Sixta Bernhard A. Wolf 《应用聚合物科学杂志》2011,119(2):670-676
The intrinsic viscosities, [η], of nine cellulose samples, with molar masses from 50 × 103 to 1 390 × 103 were determined in the solvents NMMO*H2O (N‐methyl morpholin N‐oxide hydrate) at 80°C and in cuen (copper II‐ethlenediamine) at 25°C. The evaluation of these results with respect to the Kuhn–Mark–Houwink relations shows that the data for NMMO*H2O fall on the usual straight line in the double logarithmic plots only for M ≤ 158 103; the corresponding [η]/M relation reads log ([η]/mL g−1) = –1.465 + 0.735 log M. Beyond that molar mass [η] remains almost constant up to M ≈ 106 and increases again thereafter. In contrast to NMMO*H2O the cellulose solutions in cuen behave normal and the Kuhn–Mark–Houwink relation reads log ([η]/mL g−1) = −1.185 + 0.735 log M. Possible reasons for the dissimilarities of the behavior of cellulose in these two solvents are being discussed. The comparison of three different methods for the determination of [η] from viscosity measurements at different polymer concentrations, c, demonstrates the advantages of plotting the natural logarithm of the relative viscosities as a function of c. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
18.
Microwave dielectric and nonlinear optical studies on radio‐frequency sputtered Dy2O3‐doped KNN thin films
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Mahesh Peddigari Vivek Patel Gyan Prakash Bharti Alika Khare Dobbidi Pamu 《Journal of the American Ceramic Society》2017,100(7):3013-3023
We report the effect of oxygen mixing percentage (OMP) on structural, microstructural, dielectric, linear, and nonlinear optical properties of Dy2O3‐doped (K0.5Na0.5)NbO3 thin films. The (K0.5Na0.5)NbO3 + 0.5 wt%Dy2O3 (KNN05D) ferroelectric thin films were deposited on to quartz and Pt/Ti/SiO2/Si substrates by RF magnetron sputtering. An increase in the refractive index from 2.08 to 2.21 and a decrease in the optical bandgap from 4.30 to 4.28 eV indicate the improvement in crystallinity, which is also confirmed from Raman studies. A high relative permittivity (εr=281‐332) and low loss tangent (tanδ=1.2%‐1.9%) were obtained for the films deposited in 100% OMP, measured at microwave frequencies (5‐15 GHz). The leakage current of the films found to be as low as 9.90×10?9 A/cm2 at 150 kV/cm and Poole‐Frenkel emission is the dominant conduction mechanism in the films. The third order nonlinear optical properties of the KNN05D films were investigated using modified single beam z‐scan method. The third order nonlinear susceptibility (?χ(3)?) values of KNN05D films increased from 0.69×10?3 esu to 1.40×10?3 esu with an increase in OMP. The larger and positive nonlinear refractive index n2=7.04×10?6 cm2/W, and nonlinear absorption coefficient β=1.70 cm/W were obtained for the 100% OMP film, indicating that KNN05D films are good candidates for the applications in nonlinear photonics and high‐frequency devices. 相似文献
19.
Effects of atomic oxygen (AO) and ultraviolet (UV) on a polymer film with surface energy of 8.0 mJ m−2 derived from poly(1H,1H‐perfluorooctyl methylacrylate) were investigated by contact angle measurements, X‐ray photoelectron spectroscopy, and atomic force microscope. The film was exposed to AO with a flux of 6.73 × 1015 atoms cm−2 s−1 and UV with intensity of 15.8 mW cm−2 at wavelength of 200–450 nm, respectively. It is found that AO and UV irradiation resulted in the reduction of film thickness, change of wettability, and increase of surface energy, and AO exhibited more serious effects than UV on the fluorinated polymer film. Reduced rate of thickness of the film was almost proportional to the AO exposure time. After exposed to AO and UV irradiation, the surface energy of the film increased to 17.3 mJ m−2 and 11.0 mJ m−2, respectively. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
20.
Yongbao Xiao Yao Ji Yichen Ye Shujing Huang Weichao Wang 《Journal of the American Ceramic Society》2020,103(9):5013-5027
Alkali-earth-metaphosphate-based fluoro-sulfo-phosphate M(PO3)2–AlF3–MSO4 (MPFS, M = Ca, Sr, Ba) glasses have been developed via simultaneously incorporating fluoride and sulfate into metaphosphate glass. Their glass-forming regions were efficiently determined under the guidance of thermodynamic calculation method. The physical and structural properties of BaPFS glass were investigated in detail. Furthermore, near-infrared spectroscopic properties of Er3+-doped BaPFS (Er–BaPFS) glass were studied. Physical parameters, such as Abbe's number νd (55-75) and nonlinear refractive index n2 (1.17-1.86 × 10−13 esu), of BaPFS glass are strongly depended on P/F/S ratio. The structure of BaPFS glass gradually depolymerizes and tends to become multianionic when Ba(PO3)2 is substituted by AlF3 and BaSO4. Anion-substitution strategy effectively modulates the property and structure of glass, providing a scheme to derive glass materials. In addition, enhanced emission at ~1.5 μm has been observed from Er–BaPFS glass along with large emission cross section (5.0-5.5 × 10−21 cm2) and long lifetime (6.7-7.3 ms), resulting in large figure of merit (3.46-3.84 × 10−23 cm2·s), which is a promising candidate for solid-state laser. 相似文献